Objective:To summarize the treatment strategies of Traditional Chinese Medicine(TCM)for COVID-19 in tropical regions based on the pathogens of dampness and heat.Methods:For heat pathogen,analyzing heat in the superfic...Objective:To summarize the treatment strategies of Traditional Chinese Medicine(TCM)for COVID-19 in tropical regions based on the pathogens of dampness and heat.Methods:For heat pathogen,analyzing heat in the superficies,lung and Yang Ming based on the different locations.Based on the progress of the disease,analyzing the stage of toxin and Qi deficiency induced by heat.For dampness pathogen,analyzing endogenous and external dampness based on the different locations.Analyzing dampness pathogen's special disease location—Moyuan and special symptom of dry cough with less sputum caused by sticky and stagnant characteristic of dampness.Results:The treatment strategies for heat and dampness pathogen were summarized.Conclusion:In the tropics,the pathogens of dampness and heat occur frequently and clinical treatments need to be dialectical.展开更多
Objective:To systemically review the efficacy and safety about the method of enriching qi,activating blood circulation,clearing away dampness and heat combined with western medicine in the therapy of patients with idi...Objective:To systemically review the efficacy and safety about the method of enriching qi,activating blood circulation,clearing away dampness and heat combined with western medicine in the therapy of patients with idiopathy membranous nephropathy(IMN).Methods:We collected the randomized controlled trials(RCTs)of enriching qi,activating blood circulation,clearing away dampness and heat for the treatment of IMN from Pub Med,The Cochrane Library,Medline,China National Knowledge Infrastructure(CNKI),China Biology Medicine disc(CBM),Wanfang Data and Wiper Databases.Bias of risk of retrieval literature was evaluated according to Cochrane Collaboration standard,and Review Manager 5.3 software was used for statistical analysis.Results:Fourteen trials(836 participants)were included in the meta-analysis.This kind of traditional Chinese method combined with western medicine in the treatment of IMN exerted statistical differences in reducing 24-hour urinary protein[WMD=-0.97,95%CI(-1.30,-0.65),Z=5.86(P<0.00001)]and elevating serum albumin[WMD=3.83,95%CI(2.10,5.57),Z=4.33,P<0.0001],lowering serum cholesterol[WMD=-0.82,95%CI(-1.08,-0.56),Z=6.18,P<0.00001],triglycerides[WMD=-0.39,95%CI(-0.67,-0.11),Z=2.77,P=0.006]and reducing the risk of adverse events[OR=0.29,95%CI[0.16,0.50],Z=4.35,P<0.0001]in the patients with IMN as compared with controls.However,there was no statistically significant difference between the method and controls when combining all trials in serum creatinine[WMD=-5.52,95%CI(-18.06,7.03),Z=0.86,P=0.39],when combining all trials in urea nitrogen[WMD=-0.90,95%CI(-2.22,0.41),Z=1.35,P=0.18].Conclusion:The method of enriching qi,activating blood circulation,clearing away dampness and heat combined with western medicine exerts certain advantages and better safety in treating patients with IMN.However,for the inferiority of the included studies,the conclusion still needs high-quality and large-sample prospective randomized controlled trials to verify.展开更多
Objective:To explore the clinical effects of Zhuang Medicine Yangxue Xiaozheng Decoction in treating the combined Ems of dampness and blood stasis in Guangxi;Methods:100 patients with endometriosis treated in Lili Cli...Objective:To explore the clinical effects of Zhuang Medicine Yangxue Xiaozheng Decoction in treating the combined Ems of dampness and blood stasis in Guangxi;Methods:100 patients with endometriosis treated in Lili Clinic of Famous Doctor,Guangxi International Zhuang Medicine Hospital from Mach 2016 to May 2017 were chosen as the research object.According to the random grouping method,patients were randomly divided into the treatment group(The Zhuang Medicine Yangxue Xiaozheng Decoction(ZYF)Group)and the control group(Chinese patent medicine SanJieZhenTongJiaoNang(SJZT)group with 50 cases in each group.After treatment,the TCM syndrome score,changes in pelvic mass size,hepatocyte growth factor(HGP)levels,and clinical effects before and after treatment were evaluated.Results:After two courses of treatment,the total effective rate of patients in the ZYF group was 88%,which were significantly better than 70%of the SJZT group.The difference was statistically significant(P<0.05).Conclusion:With a significant effect on patients with the combined Ems of dampness and blood stasis in Guangxi,Zhuang Medicine Yangxue Xiaozheng Decoction can improve the uterine cavity mass and reduce serum HGP level.展开更多
Based on the characteristics of the epidemic situation and the authors’understanding of the related ancient books and documents,this paper explores the etiology and pathogenesis of Corona Virus Disease 2019(COVID-19)...Based on the characteristics of the epidemic situation and the authors’understanding of the related ancient books and documents,this paper explores the etiology and pathogenesis of Corona Virus Disease 2019(COVID-19)from 5 aspects:abnormal climate in"warm winter",unique geographical location,pathogenesis evolution of cold and dampness mixed with insidious dryness,transmission and change of"triple energizer"of toxic pathogens,and game between healthy Qi and toxic pathogens.Combined with the special treatment of traditional Chinese medicine(TCM),the purpose is to make a modest contribution to curbing the epidemic situation with TCM.展开更多
This work studied the microstructure,mechanical properties and damping properties of Mg_(95.34)Ni_(2)Y_(2.66) and Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloys systematically.The difference in the evolution of the long-period ...This work studied the microstructure,mechanical properties and damping properties of Mg_(95.34)Ni_(2)Y_(2.66) and Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloys systematically.The difference in the evolution of the long-period stacked ordered(LPSO)phase in the two alloys during heat treatment was the focus.The morphology of the as-cast Mg_(95.34)Ni_(2)Y_(2.66)presented a disordered network.After heat treatment at 773 K for 2 hours,the eutectic phase was integrated into the matrix,and the LPSO phase maintained the 18R structure.As Zn partially replaced Ni,the crystal grains became rounded in the cast alloy,and lamellar LPSO phases and more solid solution atoms were contained in the matrix after heat treatment of the Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloy.Both Zn and the heat treatment had a significant effect on damping.Obvious dislocation internal friction peaks and grain boundary internal friction peaks were found after temperature-dependent damping of the Mg_(95.34)Ni_(2)Y_(2.66)and Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloys.After heat treatment,the dislocation peak was significantly increased,especially in the alloy Mg_(95.34)Ni_(2)Y_(2).66.The annealed Mg_(95.34)Ni_(2)Y_(2.66)alloy with a rod-shaped LPSO phase exhibited a good damping performance of 0.14 atε=10^(−3),which was due to the difference between the second phase and solid solution atom content.These factors also affected the dynamic modulus of the alloy.The results of this study will help in further development of high-damping magnesium alloys.展开更多
Objective:To explore the abnormal expression and significance of circ-CBLB/miR-486-5p in patients with rheumatoid arthritis of spleen deficiency and dampness excess type.Methods:The 30 healthy individuals included in ...Objective:To explore the abnormal expression and significance of circ-CBLB/miR-486-5p in patients with rheumatoid arthritis of spleen deficiency and dampness excess type.Methods:The 30 healthy individuals included in the method were from the Physical Examination Center of Anhui Provincial Hospital of Traditional Chinese Medicine,and the 60 rheumatoid arthritis patients included were from the First Affiliated Hospital of Anhui University of Traditional Chinese Medicine.The disease activity score of patients with rheumatoid arthritis was evaluated using VAS score and DAS28 score,joint symptoms and spleen deficiency syndrome score were evaluated using graded quantification method,immune inflammation indicators were detected using relevant instruments,inflammatory cytokines were detected using ELISA method,macrophage markers were detected using FCM method,and pathway gene expression was detected using RT-qPCR;Evaluate the predictive effect of circ-CBLB and miR-486-5p on disease activity in rheumatoid arthritis using ROC curves.Results:(1)miR-486-5p,CD14^(+)CD86^(+),ESR,CRP,RF,Anti CCP Ab,IL-6,TNF in patients with rheumatoid arthritis-αThe levels of circ-CBLB,CD14^(+)CD163^(+),IL-4,and IL-10 were significantly higher than those of healthy individuals;(2)The expression level of circ-CBLB in patients with rheumatoid arthritis is positively correlated with CD14^(+)CD163^(+),and negatively correlated with miR-486-5p and CD14^(+)CD86^(+);The expression level of miR-486-5p is negatively correlated with CD14^(+)CD163^(+)and positively correlated with CD14^(+)CD86^(+);There is a negative correlation between CD14^(+)CD86^(+)and CD14^(+)CD163^(+);ESR is negatively correlated with circ-CBLB,and positively correlated with miR-486-5p,CD14^(+)CD86^(+),CRP;CRP is negatively correlated with circ-CBLB,CD14^(+)CD163^(+),and positively correlated with CD14^(+)CD86^(+),ESR;(3)The expression level of circ-CBLB in patients with rheumatoid arthritis is negatively correlated with joint tenderness,morning stiffness,lack of qi and lazy speech,and postprandial abdominal distension score;The expression level of miR-486-5p is positively correlated with the scores of joint tenderness and decreased appetite.(4)The ROC curve shows that in terms of circ-CBLB,ESR,CRP,VAS,and DAS28 AUC are 0.662(P=0.032),0.658(P=0.035),0.516(P=0.830),and 0.791(P=0.000),respectively.In terms of miR-486-5p,ESR,CRP,VAS,and DAS28 AUC were 0.566(P=0.385),0.511(P=0.883),0.592(P=0.223),and 0.727(P=0.003),respectively.Conclusion:The abnormal expression of circ CBLB and miR-486-5p in peripheral blood mononuclear cell of patients with rheumatoid arthritis of spleen deficiency and dampness excess type is related to inflammatory polarization markers,immune inflammation,disease activity,joint symptoms and spleen deficiency syndrome of rheumatoid arthritis,and the low expression of circ CBLB and high expression of miR-486-5p have certain predictive value for disease activity of rheumatoid arthritis.展开更多
Flexible damping technology considering aseismic materials and aseismic structures seems be a good solution for engineering structures.In this study,a constrained damping structure for underground tunnel lining,using ...Flexible damping technology considering aseismic materials and aseismic structures seems be a good solution for engineering structures.In this study,a constrained damping structure for underground tunnel lining,using a rubber-sand-concrete(RSC)as the aseismic material,is proposed.The aseismic performances of constrained damping structure were investigated by a series of hammer impact tests.The damping layer thickness and shape effects on the aseismic performance such as effective duration and acceleration amplitude of time-domain analysis,composite loss factor and damping ratio of the transfer function analysis,and total vibration level of octave spectrum analysis were discussed.The hammer impact tests revealed that the relationship between the aseismic performance and damping layer thickness was not linear,and that the hollow damping layer had a better aseismic performance than the flat damping layer one.The aseismic performances of constrained damping structure under different seismicity magnitudes and geological conditions were investigated.The effects of the peak ground acceleration(PGA)and tunnel overburden depth on the aseismic performances such as the maximum principal stress and equivalent plastic strain(PEEQ)were discussed.The numerical results show the constrained damping structure proposed in this paper has a good aseismic performance,with PGA in the range(0.2-1.2)g and tunnel overburden depth in the range of 0-300 m.展开更多
Objective:To observe the clinical effect of electroacupuncture on improving polycystic ovary syndrome(PCOS)of kidney deficiency and phlegm dampness type and serum oxidative stress level.Methods:There were 68 patients ...Objective:To observe the clinical effect of electroacupuncture on improving polycystic ovary syndrome(PCOS)of kidney deficiency and phlegm dampness type and serum oxidative stress level.Methods:There were 68 patients with polycystic ovary syndrome were randomly divided into observation group(34 cases)and the control group(34 cases),The observation group was treated by electroacupuncture,while the control group was treated by placebo electroacupuncture.Combined with the evaluation of menstrual cycle,menstrual color,quality,quantity and TCM symptom integral index,the difference of curative effect between the two groups was observed,and the levels of peripheral blood,sex hormones,insulin resistance and oxidative stress were detected before and after treatment for 3 months.Results:The total effective rate in the observation group was better than that in the control group(P<0.01);After intervention,serum LH,FSH,E_(2) and LH/FSH in the observation group were significantly different from those before intervention.The D values of serum LH,FSH,LH/FSH and E_(2) before and after intervention were significantly different between the two groups(P<0.01);Comparing the level of androgen,the serum A4 and T in the observation group were significantly different from those before intervention(P<0.01);After intervention,there was a significant difference in serum A4 and T between the two groups(P<0.01),and there was a significant difference in D value between the two groups before and after intervention;There was a difference in insulin resistance in the observation group before and after intervention(P<0.05),and there was a significant difference in D value between the two groups before and after intervention(P<0.01);After the intervention,the serum SOD,MDA,ROS in the observation group were significantly different from those before the intervention;After intervention,the results of serum SOD and ROS in the observation group were significantly different from those in the control group;There was no significant difference in serum MDA results.There were significant differences in SOD,MDA,ROS between the two groups before and after intervention.Conclusion:Electroacupuncture can improve oxidative stress injury,insulin resistance and hyperandrogenism in PCOS patients.展开更多
Lattice metamaterials based on three-period minimum surface(TPMS)are an effective means to achieve lightweight and high-strength materials which are widely used in various fields such as aerospace and ships.However,it...Lattice metamaterials based on three-period minimum surface(TPMS)are an effective means to achieve lightweight and high-strength materials which are widely used in various fields such as aerospace and ships.However,its vibration and noise reduction,and damping properties have not been fully studied.Therefore,in this study,the TPMS structures with parameterization were designed by the method of surface migration,and the TPMS structures with high forming quality was manufactured by laser powder bed fusion(LPBF).The mechanical properties and energy absorption characteristics of the beam and TPMS structures were studied and compared by quasi-static compression.The modal shapes of the beam lattice structures and TPMS structures were obtained by the free modal analysis,and the damping properties of two structures were obtained by modal tests.For the two structures after heat treatment with the same porosity of 70%,the yield strength of the beam lattice structure reaches 40.76 MPa,elastic modulus is 20.38 GPa,the energy absorption value is 32.23 MJ·m^(-3),the damping ratio is 0.52%.The yield strength,elastic modulus,energy absorption value,and damping ratio of the TPMS structure are 50.74 MPa,25.37 GPa,47.34 MJ·m^(-3),and 0.99%,respectively.The results show that TPMS structures exhibit more excellent mechanical properties and energy absorption,better damping performance,and obvious advantages in structural load and vibration and noise reduction compared with the beam lattice structures under the same porosity.展开更多
Nonlinear energy sink is a passive energy absorption device that surpasses linear dampers, and has gained significant attention in various fields of vibration suppression. This is owing to its capacity to offer high v...Nonlinear energy sink is a passive energy absorption device that surpasses linear dampers, and has gained significant attention in various fields of vibration suppression. This is owing to its capacity to offer high vibration attenuation and robustness across a wide frequency spectrum. Energy harvester is a device employed to convert kinetic energy into usable electric energy. In this paper, we propose an electromagnetic energy harvester enhanced viscoelastic nonlinear energy sink(VNES) to achieve passive vibration suppression and energy harvesting simultaneously. A critical departure from prior studies is the investigation of the stochastic P-bifurcation of the electromechanically coupled VNES system under narrowband random excitation. Initially, approximate analytical solutions are derived using a combination of a multiple-scale method and a perturbation approach. The substantial agreement between theoretical analysis solutions and numerical solutions obtained from Monte Carlo simulation underscores the method's high degree of validity. Furthermore, the effects of system parameters on system responses are carefully examined. Additionally, we demonstrate that stochastic P-bifurcation can be induced by system parameters, which is further verified by the steady-state density functions of displacement. Lastly,we analyze the impacts of various parameters on the mean square current and the mean output power, which are crucial for selecting suitable parameters to enhance the energy harvesting performance.展开更多
SiC particles were added to the Mg97Zn1Y2 alloy to improve its mechanical properties and damping properties.The microstructure,mechanical properties,and strain amplitude dependence of high-damping and high-strength Si...SiC particles were added to the Mg97Zn1Y2 alloy to improve its mechanical properties and damping properties.The microstructure,mechanical properties,and strain amplitude dependence of high-damping and high-strength SiC/Mg97Zn1Y2 magnesium matrix composites were analyzed.The strain amplitude-dependent damping of SiC/Mg97Zn1Y2 composites and the effect of SiC on this property were discussed herein.In anelastic damping,the strain amplitude-dependent damping curves of the composites were mainly divided into two sections,dominated by the G-L model.When the strain amplitude reaches a certain value,the dislocation motion inside the matrix becomes complicated.Moreover,the damping of the material could not be explained using the G-L model,and a new damping model related to microplastic deformation was proposed.In the anelastic damping stage,with the increase in the amount of the added SiC particles,the damping performance first increases and then decreases.Moreover,the damping value of the composite material is larger than that of the matrix alloy.In the microplastic deformation stage,the damping properties of the composites and matrix alloys considerably increase with the strain amplitude.展开更多
The damping properties were improved by preparing Al matrix composites reinforced with glass cenospheres through the pressure infiltration method.Transmission electron microscopy and scanning electron microscopy were ...The damping properties were improved by preparing Al matrix composites reinforced with glass cenospheres through the pressure infiltration method.Transmission electron microscopy and scanning electron microscopy were employed to characterize the microstructure of the composites.The low-frequency damping properties were examined by using a dynamic mechanical thermal analyzer,aiming at exploring the changing trend of damping capacity with strain,temperature,and frequency.The findings demonstrated that the damping value rose as temperature and strain increased,with a maximum value of 0.15.Additionally,the damping value decreased when the frequency increased.Dislocation damping under strain and interfacial damping under temperature served as the two primary damping mechanisms.The increase in the density of dislocation strong pinning points following heat treatment reduced the damping value,which was attributed to the heat treatment enhancement of the interfacial bonding force of the composites.展开更多
Base isolators used in buildings provide both a good acceleration reduction and structural vibration control structures.The base isolators may lose their damping capacity over time due to environmental or dynamic effe...Base isolators used in buildings provide both a good acceleration reduction and structural vibration control structures.The base isolators may lose their damping capacity over time due to environmental or dynamic effects.This deterioration of them requires the determination of the maintenance and repair needs and is important for the long-termisolator life.In this study,an artificial intelligence prediction model has been developed to determine the damage and maintenance-repair requirements of isolators as a result of environmental effects and dynamic factors over time.With the developed model,the required damping capacity of the isolator structure was estimated and compared with the previously placed isolator capacity,and the decrease in the damping property was tried to be determined.For this purpose,a data set was created by collecting the behavior of structures with single degrees of freedom(SDOF),different stiffness,damping ratio and natural period isolated from the foundation under far fault earthquakes.The data is divided into 5 different damping classes varying between 10%and 50%.Machine learning model was trained in damping classes with the data on the structure’s response to random seismic vibrations.As a result of the isolator behavior under randomly selected earthquakes,the recorded motion and structural acceleration of the structure against any seismic vibration were examined,and the decrease in the damping capacity was estimated on a class basis.The performance loss of the isolators,which are separated according to their damping properties,has been tried to be determined,and the reductions in the amounts to be taken into account have been determined by class.In the developed prediction model,using various supervised machine learning classification algorithms,the classification algorithm providing the highest precision for the model has been decided.When the results are examined,it has been determined that the damping of the isolator structure with the machine learning method is predicted successfully at a level exceeding 96%,and it is an effective method in deciding whether there is a decrease in the damping capacity.展开更多
To explore the wide-frequency damping and vibration-attenuation performances in the application of aerospace components,the cylindrical sandwich shell structure with a gradient core of entangled wire mesh was proposed...To explore the wide-frequency damping and vibration-attenuation performances in the application of aerospace components,the cylindrical sandwich shell structure with a gradient core of entangled wire mesh was proposed in this paper.Firstly,the gradient cores of entangled wire mesh in the axial and radial directions were prepared by using an in-house Numerical Control weaving machine,and the metallurgical connection between skin sheets and the gradient core was performed using vacuum brazing.Secondly,to investigate the mechanical properties of cylindrical sandwich shells with axial or radial gradient cores,quasi-static and dynamic mechanical experiments were carried out.The primary evaluations of mechanical properties include secant stiffness,natural frequency,Specific Energy Absorption(SEA),vibration acceleration level,and so on.The results suggest that the vibration-attenuation performance of the sandwich shell is remarkable when the high-density core layer is at the end of the shell or abuts the inner skin.The axial gradient material has almost no influence on the vibration frequencies of the shell,whereas the vibration frequencies increase dramatically when the high-density core layer approaches the skin.Moreover,compared to the conventional sandwich shells,the proposed functional grading cylindrical sandwich shell exhibits more potential in mass reduction,stiffness designing,and energy dissipation.展开更多
Strong impact does serious harm to the military industries so it is necessary to choose reasonable cushioning material and design effective buffers to prevent the impact of equipment.Based on the capillary property en...Strong impact does serious harm to the military industries so it is necessary to choose reasonable cushioning material and design effective buffers to prevent the impact of equipment.Based on the capillary property entangled porous metallic wire materials(EPMWM),this paper designed a composite buffer which uses EPMWM and viscous fluid as cushioning materials under the low-speed impact of the recoil force device of weapon equipment(such as artillery,mortar,etc.).Combined with the capillary model,porosity,hydraulic diameter,maximum pore diameter and pore distribution were used to characterize the pore structure characteristics of EPMWM.The calculation model of the damping force of the composite buffer was established.The low-speed impact test of the composite buffer was conducted.The parameters of the buffer under low-speed impact were identified according to the model,and the nonlinear model of damping force was obtained.The test results show that the composite buffer with EPMWM and viscous fluid can absorb the impact energy from the recoil movement effectively,and provide a new method for the buffer design of weapon equipment(such as artillery,mortar,etc.).展开更多
The problems associated with vibrations of viaducts and low-frequency structural noise radiation caused by train excitation continue to increase in importance.A new floating-slab track vibration isolator-non-obstructi...The problems associated with vibrations of viaducts and low-frequency structural noise radiation caused by train excitation continue to increase in importance.A new floating-slab track vibration isolator-non-obstructive particle damping-phononic crystal vibration isolator is proposed herein,which uses the particle damping vibration absorption technology and bandgap vibration control theory.The vibration reduction performance of the NOPD-PCVI was analyzed from the perspective of vibration control.The paper explores the structure-borne noise reduction performance of the NOPD-PCVIs installed on different bridge structures under varying service conditions encountered in practical engineering applications.The load transferred to the bridge is obtained from a coupled train-FST-bridge analytical model considering the different structural parameters of bridges.The vibration responses are obtained using the finite element method,while the structural noise radiation is simulated using the frequency-domain boundary element method.Using the particle swarm optimization algorithm,the parameters of the NOPD-PCVI are optimized so that its frequency bandgap matches the dominant bridge structural noise frequency range.The noise reduction performance of the NOPD-PCVIs is compared to the steel-spring isolation under different service conditions.展开更多
High-frequency oscillation(HFO)of gridconnected wind power generation systems(WPGS)is one of the most critical issues in recent years that threaten the safe access of WPGS to the grid.Ensuring the WPGS can damp HFO is...High-frequency oscillation(HFO)of gridconnected wind power generation systems(WPGS)is one of the most critical issues in recent years that threaten the safe access of WPGS to the grid.Ensuring the WPGS can damp HFO is becoming more and more vital for the development of wind power.The HFO phenomenon of wind turbines under different scenarios usually has different mechanisms.Hence,engineers need to acquire the working mechanisms of the different HFO damping technologies and select the appropriate one to ensure the effective implementation of oscillation damping in practical engineering.This paper introduces the general assumptions of WPGS when analyzing HFO,systematically summarizes the reasons for the occurrence of HFO in different scenarios,deeply analyses the key points and difficulties of HFO damping under different scenarios,and then compares the technical performances of various types of HFO suppression methods to provide adequate references for engineers in the application of technology.Finally,this paper discusses possible future research difficulties in the problem of HFO,as well as the possible future trends in the demand for HFO damping.展开更多
The application of carbon nanomaterials, particularly graphene and carbon nanotubes, in cement-based composites is highly significant. These materials demonstrate the multifunctionality of carbon and offer extensive p...The application of carbon nanomaterials, particularly graphene and carbon nanotubes, in cement-based composites is highly significant. These materials demonstrate the multifunctionality of carbon and offer extensive possibilities for technological advancements. This research analyzes how the integration of graphene into cement-based composites enhances damping and mechanical properties, thereby contributing to the safety and durability of structures. Research on carbon nanomaterials is ongoing and is expected to continue driving innovation across various industrial sectors, promoting the sustainable development of building materials.展开更多
This paper conducted experimental studies on the damping and mechanical properties of carbon nanotube-nanosilica-cement composite materials with different carbon nanotube contents. The damping and mechanical propertie...This paper conducted experimental studies on the damping and mechanical properties of carbon nanotube-nanosilica-cement composite materials with different carbon nanotube contents. The damping and mechanical properties enhancement mechanisms were analyzed and compared through the porosity structure test, XRD analysis, and scanning electron microscope observation. The results show that the introduction of nanosilica significantly improves the dispersion of carbon nanotubes in the cement matrix. At the same time, the addition of nanosilica not only effectively reduces the critical pore size and average pore size of the cement composite material, but also exhibits good synergistic effects with carbon nanotubes, which can significantly optimize the pore structure. Finally, a rationalization suggestion for the co-doping of nanosilica and carbon nanotubes was given to achieve a significant increase in the flexural strength, compressive strength and loss factor of cement-based materials.展开更多
Objective:To evaluate the efficacy and safety of a Chinese medicine(CM)Modified Qufeng Runmian Powder(加减祛风润面散,MQFRMP)for the treatment of acne vulgaris with CM syndromes of dampness and blood stasis.Methods:In ...Objective:To evaluate the efficacy and safety of a Chinese medicine(CM)Modified Qufeng Runmian Powder(加减祛风润面散,MQFRMP)for the treatment of acne vulgaris with CM syndromes of dampness and blood stasis.Methods:In this multicenter,randomized,double-blind,placebo-controlled clinical trial,220 acne vulgaris patients with CM syndrome of dampness and blood stasis were included and randomly assigned using a central area group random design to receive either MQFRMP or the placebo,with 110 cases in each group.MQFRMP or a placebo at 145 g/bag were administered once daily for 4 weeks,respectively.The primary index of efficacy was the effective rate according to the acne severity score(ASS).The secondary indices of efficacy included the changes in the dermatology life quality index(DLQI)score,VISIA scores(spots,pores,brown spots,porphyrins and red areas)and skin assessment(skin p H,sebum amount and hydration)according to a SOFT skin multianalyzer.Results:(1)Follow-up:a total of 204 patients completed the follow-up,with 103 in the treatment group and 101 in the control group.(2)Effective rate:the total effective rate of the treatment group was significantly higher than the control group[83.5%(86/103)vs.31.7%(32/101),P<0.01)]with 95%confidence interval of 39.3%–66.4%.(3)DLQI:DLQI scores were significantly decreased the treatment and control groups(both P<0.01),but the treatment group was more obvious than the placebo group(P<0.01).(4)VISIA scores:the scores of spots,brown spots and red areas in the treatment group decreased compared with baseline(P<0.05).In the control group,the scores of brown spots and pores decreased compared with baseline(P<0.05).The improvement was more obvious in the treatment group than in the control group for all items(P<0.05).(5)Skin assessment:the p H and sebum score in the both groups decreased drastically compared with the baseline(all P<0.01),however,the improvement was more obvious in the treatment group than in the control group(P<0.01).The hydration amount in the two groups showed no statistically significant difference compared with the baseline(both P>0.05).(6)Safety:two cases of mild drug allergy were observed in the treatment group.Conclusion:MQFRMP was effective and safe for the treatment of acne vulgaris with syndromes of dampness and blood stasis.(No.ChiCTR1900020479).展开更多
基金Science and technology of 2019-nCoV in Hainan medical university(No.XGZX2020006)
文摘Objective:To summarize the treatment strategies of Traditional Chinese Medicine(TCM)for COVID-19 in tropical regions based on the pathogens of dampness and heat.Methods:For heat pathogen,analyzing heat in the superficies,lung and Yang Ming based on the different locations.Based on the progress of the disease,analyzing the stage of toxin and Qi deficiency induced by heat.For dampness pathogen,analyzing endogenous and external dampness based on the different locations.Analyzing dampness pathogen's special disease location—Moyuan and special symptom of dry cough with less sputum caused by sticky and stagnant characteristic of dampness.Results:The treatment strategies for heat and dampness pathogen were summarized.Conclusion:In the tropics,the pathogens of dampness and heat occur frequently and clinical treatments need to be dialectical.
基金Scientific Research Special Project of Capital Health Development in 2018(No.First issues 2018-1-4192)TCM Science and Technology Development Fund of Beijing in 2020(No.JJ-2020-42)。
文摘Objective:To systemically review the efficacy and safety about the method of enriching qi,activating blood circulation,clearing away dampness and heat combined with western medicine in the therapy of patients with idiopathy membranous nephropathy(IMN).Methods:We collected the randomized controlled trials(RCTs)of enriching qi,activating blood circulation,clearing away dampness and heat for the treatment of IMN from Pub Med,The Cochrane Library,Medline,China National Knowledge Infrastructure(CNKI),China Biology Medicine disc(CBM),Wanfang Data and Wiper Databases.Bias of risk of retrieval literature was evaluated according to Cochrane Collaboration standard,and Review Manager 5.3 software was used for statistical analysis.Results:Fourteen trials(836 participants)were included in the meta-analysis.This kind of traditional Chinese method combined with western medicine in the treatment of IMN exerted statistical differences in reducing 24-hour urinary protein[WMD=-0.97,95%CI(-1.30,-0.65),Z=5.86(P<0.00001)]and elevating serum albumin[WMD=3.83,95%CI(2.10,5.57),Z=4.33,P<0.0001],lowering serum cholesterol[WMD=-0.82,95%CI(-1.08,-0.56),Z=6.18,P<0.00001],triglycerides[WMD=-0.39,95%CI(-0.67,-0.11),Z=2.77,P=0.006]and reducing the risk of adverse events[OR=0.29,95%CI[0.16,0.50],Z=4.35,P<0.0001]in the patients with IMN as compared with controls.However,there was no statistically significant difference between the method and controls when combining all trials in serum creatinine[WMD=-5.52,95%CI(-18.06,7.03),Z=0.86,P=0.39],when combining all trials in urea nitrogen[WMD=-0.90,95%CI(-2.22,0.41),Z=1.35,P=0.18].Conclusion:The method of enriching qi,activating blood circulation,clearing away dampness and heat combined with western medicine exerts certain advantages and better safety in treating patients with IMN.However,for the inferiority of the included studies,the conclusion still needs high-quality and large-sample prospective randomized controlled trials to verify.
基金Project for Improving Basic Capabilities of Middle-aged and Young Teachers in Guangxi Institutions of Higher Learning(No.KY2016YB833Open Project for Guangxi First-class Discipline Construction of Guangxi University of Chinese Medicine(No.2019XK038)Funded by Development Program of High-level Talent Team under Qihuang Project of Guangxi University of Chinese Medicine(No.2018005).
文摘Objective:To explore the clinical effects of Zhuang Medicine Yangxue Xiaozheng Decoction in treating the combined Ems of dampness and blood stasis in Guangxi;Methods:100 patients with endometriosis treated in Lili Clinic of Famous Doctor,Guangxi International Zhuang Medicine Hospital from Mach 2016 to May 2017 were chosen as the research object.According to the random grouping method,patients were randomly divided into the treatment group(The Zhuang Medicine Yangxue Xiaozheng Decoction(ZYF)Group)and the control group(Chinese patent medicine SanJieZhenTongJiaoNang(SJZT)group with 50 cases in each group.After treatment,the TCM syndrome score,changes in pelvic mass size,hepatocyte growth factor(HGP)levels,and clinical effects before and after treatment were evaluated.Results:After two courses of treatment,the total effective rate of patients in the ZYF group was 88%,which were significantly better than 70%of the SJZT group.The difference was statistically significant(P<0.05).Conclusion:With a significant effect on patients with the combined Ems of dampness and blood stasis in Guangxi,Zhuang Medicine Yangxue Xiaozheng Decoction can improve the uterine cavity mass and reduce serum HGP level.
基金the funding support from the National Natural Science Foundation of China(No.81774126)Hunan Provincial Innovation Foundation for Postgraduate(No.CX2018B481)Program for First-class Disciplines of Hunan Province in the Direction of Traditional Chinese and Western Medicine(No.2018ZXYJH20).
文摘Based on the characteristics of the epidemic situation and the authors’understanding of the related ancient books and documents,this paper explores the etiology and pathogenesis of Corona Virus Disease 2019(COVID-19)from 5 aspects:abnormal climate in"warm winter",unique geographical location,pathogenesis evolution of cold and dampness mixed with insidious dryness,transmission and change of"triple energizer"of toxic pathogens,and game between healthy Qi and toxic pathogens.Combined with the special treatment of traditional Chinese medicine(TCM),the purpose is to make a modest contribution to curbing the epidemic situation with TCM.
基金funded by the National Natural Science Foundation of China(Nos.51801189)The Central Guidance on Local Science and Technology Development Fund of Shanxi Province(Nos.YDZJTSX2021A027)+2 种基金The National Natural Science Foundation of China(Nos.51801189)The Science and Technology Major Project of Shanxi Province(No.20191102008,20191102007)The North University of China Youth Academic Leader Project(No.11045505).
文摘This work studied the microstructure,mechanical properties and damping properties of Mg_(95.34)Ni_(2)Y_(2.66) and Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloys systematically.The difference in the evolution of the long-period stacked ordered(LPSO)phase in the two alloys during heat treatment was the focus.The morphology of the as-cast Mg_(95.34)Ni_(2)Y_(2.66)presented a disordered network.After heat treatment at 773 K for 2 hours,the eutectic phase was integrated into the matrix,and the LPSO phase maintained the 18R structure.As Zn partially replaced Ni,the crystal grains became rounded in the cast alloy,and lamellar LPSO phases and more solid solution atoms were contained in the matrix after heat treatment of the Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloy.Both Zn and the heat treatment had a significant effect on damping.Obvious dislocation internal friction peaks and grain boundary internal friction peaks were found after temperature-dependent damping of the Mg_(95.34)Ni_(2)Y_(2.66)and Mg_(95.34)Zn_(1)Ni_(1)Y_(2.66)alloys.After heat treatment,the dislocation peak was significantly increased,especially in the alloy Mg_(95.34)Ni_(2)Y_(2).66.The annealed Mg_(95.34)Ni_(2)Y_(2.66)alloy with a rod-shaped LPSO phase exhibited a good damping performance of 0.14 atε=10^(−3),which was due to the difference between the second phase and solid solution atom content.These factors also affected the dynamic modulus of the alloy.The results of this study will help in further development of high-damping magnesium alloys.
基金the Seventh Batch of Inheritance Project of Academic Experience of National Veteran TCM Experts of the National Administration of Traditional Chinese Medicine (GZYYRJH[2022]No. 76)National Natural Science Foundation General Project (No.81973655)+4 种基金National Natural Science Foundation General Project (No.82274501)Anhui Provincial Excellent Youth Talent Support Program for Universities (Anhui Education Secretary [2022]No. 11)Key Laboratory of Xin'an Medical Education Department (No.2020xayx04)Natural Science Research Project of Universities in Anhui Province (No.KJ2020A0397)Anhui NewEra Education Quality Engineering Project (No.2022xscx103)。
文摘Objective:To explore the abnormal expression and significance of circ-CBLB/miR-486-5p in patients with rheumatoid arthritis of spleen deficiency and dampness excess type.Methods:The 30 healthy individuals included in the method were from the Physical Examination Center of Anhui Provincial Hospital of Traditional Chinese Medicine,and the 60 rheumatoid arthritis patients included were from the First Affiliated Hospital of Anhui University of Traditional Chinese Medicine.The disease activity score of patients with rheumatoid arthritis was evaluated using VAS score and DAS28 score,joint symptoms and spleen deficiency syndrome score were evaluated using graded quantification method,immune inflammation indicators were detected using relevant instruments,inflammatory cytokines were detected using ELISA method,macrophage markers were detected using FCM method,and pathway gene expression was detected using RT-qPCR;Evaluate the predictive effect of circ-CBLB and miR-486-5p on disease activity in rheumatoid arthritis using ROC curves.Results:(1)miR-486-5p,CD14^(+)CD86^(+),ESR,CRP,RF,Anti CCP Ab,IL-6,TNF in patients with rheumatoid arthritis-αThe levels of circ-CBLB,CD14^(+)CD163^(+),IL-4,and IL-10 were significantly higher than those of healthy individuals;(2)The expression level of circ-CBLB in patients with rheumatoid arthritis is positively correlated with CD14^(+)CD163^(+),and negatively correlated with miR-486-5p and CD14^(+)CD86^(+);The expression level of miR-486-5p is negatively correlated with CD14^(+)CD163^(+)and positively correlated with CD14^(+)CD86^(+);There is a negative correlation between CD14^(+)CD86^(+)and CD14^(+)CD163^(+);ESR is negatively correlated with circ-CBLB,and positively correlated with miR-486-5p,CD14^(+)CD86^(+),CRP;CRP is negatively correlated with circ-CBLB,CD14^(+)CD163^(+),and positively correlated with CD14^(+)CD86^(+),ESR;(3)The expression level of circ-CBLB in patients with rheumatoid arthritis is negatively correlated with joint tenderness,morning stiffness,lack of qi and lazy speech,and postprandial abdominal distension score;The expression level of miR-486-5p is positively correlated with the scores of joint tenderness and decreased appetite.(4)The ROC curve shows that in terms of circ-CBLB,ESR,CRP,VAS,and DAS28 AUC are 0.662(P=0.032),0.658(P=0.035),0.516(P=0.830),and 0.791(P=0.000),respectively.In terms of miR-486-5p,ESR,CRP,VAS,and DAS28 AUC were 0.566(P=0.385),0.511(P=0.883),0.592(P=0.223),and 0.727(P=0.003),respectively.Conclusion:The abnormal expression of circ CBLB and miR-486-5p in peripheral blood mononuclear cell of patients with rheumatoid arthritis of spleen deficiency and dampness excess type is related to inflammatory polarization markers,immune inflammation,disease activity,joint symptoms and spleen deficiency syndrome of rheumatoid arthritis,and the low expression of circ CBLB and high expression of miR-486-5p have certain predictive value for disease activity of rheumatoid arthritis.
基金supported by the National Natural Science Foundation of China(No.52079133)CRSRI Open Research Program(Program SN:CKWV2019746/KY)+1 种基金the project of Key Laboratory of Water Grid Project and Regulation of Ministry of Water Resources(QTKS0034W23291)the Youth Innovation Promotion Association CAS.
文摘Flexible damping technology considering aseismic materials and aseismic structures seems be a good solution for engineering structures.In this study,a constrained damping structure for underground tunnel lining,using a rubber-sand-concrete(RSC)as the aseismic material,is proposed.The aseismic performances of constrained damping structure were investigated by a series of hammer impact tests.The damping layer thickness and shape effects on the aseismic performance such as effective duration and acceleration amplitude of time-domain analysis,composite loss factor and damping ratio of the transfer function analysis,and total vibration level of octave spectrum analysis were discussed.The hammer impact tests revealed that the relationship between the aseismic performance and damping layer thickness was not linear,and that the hollow damping layer had a better aseismic performance than the flat damping layer one.The aseismic performances of constrained damping structure under different seismicity magnitudes and geological conditions were investigated.The effects of the peak ground acceleration(PGA)and tunnel overburden depth on the aseismic performances such as the maximum principal stress and equivalent plastic strain(PEEQ)were discussed.The numerical results show the constrained damping structure proposed in this paper has a good aseismic performance,with PGA in the range(0.2-1.2)g and tunnel overburden depth in the range of 0-300 m.
基金The Budget Project of Shanghai University of Traditional Chinese Medicine(2020LK083)General Project of Traditional Chinese Medicine Research of Shanghai Hongkou District Health Association(HKQ-ZYY-2021-15)+2 种基金Shanghai Natural Science Foundation Project(19ZR1451700)Shanghai Young Science and Technology Talents Sailing Program Project(20YF1445800)Chinese Medicine Research Project of Shanghai Health and Wellness Committee(2020JQ004)。
文摘Objective:To observe the clinical effect of electroacupuncture on improving polycystic ovary syndrome(PCOS)of kidney deficiency and phlegm dampness type and serum oxidative stress level.Methods:There were 68 patients with polycystic ovary syndrome were randomly divided into observation group(34 cases)and the control group(34 cases),The observation group was treated by electroacupuncture,while the control group was treated by placebo electroacupuncture.Combined with the evaluation of menstrual cycle,menstrual color,quality,quantity and TCM symptom integral index,the difference of curative effect between the two groups was observed,and the levels of peripheral blood,sex hormones,insulin resistance and oxidative stress were detected before and after treatment for 3 months.Results:The total effective rate in the observation group was better than that in the control group(P<0.01);After intervention,serum LH,FSH,E_(2) and LH/FSH in the observation group were significantly different from those before intervention.The D values of serum LH,FSH,LH/FSH and E_(2) before and after intervention were significantly different between the two groups(P<0.01);Comparing the level of androgen,the serum A4 and T in the observation group were significantly different from those before intervention(P<0.01);After intervention,there was a significant difference in serum A4 and T between the two groups(P<0.01),and there was a significant difference in D value between the two groups before and after intervention;There was a difference in insulin resistance in the observation group before and after intervention(P<0.05),and there was a significant difference in D value between the two groups before and after intervention(P<0.01);After the intervention,the serum SOD,MDA,ROS in the observation group were significantly different from those before the intervention;After intervention,the results of serum SOD and ROS in the observation group were significantly different from those in the control group;There was no significant difference in serum MDA results.There were significant differences in SOD,MDA,ROS between the two groups before and after intervention.Conclusion:Electroacupuncture can improve oxidative stress injury,insulin resistance and hyperandrogenism in PCOS patients.
基金financially supported by the Liaoning Province Applied Fundamental Research Program(No.2023JH2/101700039)Liaoning Province Natural Science Foundation(No.2023-MSLH-328)。
文摘Lattice metamaterials based on three-period minimum surface(TPMS)are an effective means to achieve lightweight and high-strength materials which are widely used in various fields such as aerospace and ships.However,its vibration and noise reduction,and damping properties have not been fully studied.Therefore,in this study,the TPMS structures with parameterization were designed by the method of surface migration,and the TPMS structures with high forming quality was manufactured by laser powder bed fusion(LPBF).The mechanical properties and energy absorption characteristics of the beam and TPMS structures were studied and compared by quasi-static compression.The modal shapes of the beam lattice structures and TPMS structures were obtained by the free modal analysis,and the damping properties of two structures were obtained by modal tests.For the two structures after heat treatment with the same porosity of 70%,the yield strength of the beam lattice structure reaches 40.76 MPa,elastic modulus is 20.38 GPa,the energy absorption value is 32.23 MJ·m^(-3),the damping ratio is 0.52%.The yield strength,elastic modulus,energy absorption value,and damping ratio of the TPMS structure are 50.74 MPa,25.37 GPa,47.34 MJ·m^(-3),and 0.99%,respectively.The results show that TPMS structures exhibit more excellent mechanical properties and energy absorption,better damping performance,and obvious advantages in structural load and vibration and noise reduction compared with the beam lattice structures under the same porosity.
基金Project supported by the National Natural Science Foundation of China(Grant No.12002089)the Science and Technology Projects in Guangzhou(Grant No.2023A04J1323)UKRI Horizon Europe Guarantee(Grant No.EP/Y016130/1)。
文摘Nonlinear energy sink is a passive energy absorption device that surpasses linear dampers, and has gained significant attention in various fields of vibration suppression. This is owing to its capacity to offer high vibration attenuation and robustness across a wide frequency spectrum. Energy harvester is a device employed to convert kinetic energy into usable electric energy. In this paper, we propose an electromagnetic energy harvester enhanced viscoelastic nonlinear energy sink(VNES) to achieve passive vibration suppression and energy harvesting simultaneously. A critical departure from prior studies is the investigation of the stochastic P-bifurcation of the electromechanically coupled VNES system under narrowband random excitation. Initially, approximate analytical solutions are derived using a combination of a multiple-scale method and a perturbation approach. The substantial agreement between theoretical analysis solutions and numerical solutions obtained from Monte Carlo simulation underscores the method's high degree of validity. Furthermore, the effects of system parameters on system responses are carefully examined. Additionally, we demonstrate that stochastic P-bifurcation can be induced by system parameters, which is further verified by the steady-state density functions of displacement. Lastly,we analyze the impacts of various parameters on the mean square current and the mean output power, which are crucial for selecting suitable parameters to enhance the energy harvesting performance.
基金Funded by the National Natural Science Foundation of China(No.51665012)。
文摘SiC particles were added to the Mg97Zn1Y2 alloy to improve its mechanical properties and damping properties.The microstructure,mechanical properties,and strain amplitude dependence of high-damping and high-strength SiC/Mg97Zn1Y2 magnesium matrix composites were analyzed.The strain amplitude-dependent damping of SiC/Mg97Zn1Y2 composites and the effect of SiC on this property were discussed herein.In anelastic damping,the strain amplitude-dependent damping curves of the composites were mainly divided into two sections,dominated by the G-L model.When the strain amplitude reaches a certain value,the dislocation motion inside the matrix becomes complicated.Moreover,the damping of the material could not be explained using the G-L model,and a new damping model related to microplastic deformation was proposed.In the anelastic damping stage,with the increase in the amount of the added SiC particles,the damping performance first increases and then decreases.Moreover,the damping value of the composite material is larger than that of the matrix alloy.In the microplastic deformation stage,the damping properties of the composites and matrix alloys considerably increase with the strain amplitude.
基金financially supported by the National Key Research and Development Program of China(No.2022YFE0121400)the National Natural Science Foundation of China(Nos.52071117,52111530297,51601047)+1 种基金the Heilongjiang Provincial Science Fund for Distinguished Young Scholars,China(No.JQ2021E002)the Guangdong Basic and Applied Basic Research Foundation,China(No.2022B1515120016)。
文摘The damping properties were improved by preparing Al matrix composites reinforced with glass cenospheres through the pressure infiltration method.Transmission electron microscopy and scanning electron microscopy were employed to characterize the microstructure of the composites.The low-frequency damping properties were examined by using a dynamic mechanical thermal analyzer,aiming at exploring the changing trend of damping capacity with strain,temperature,and frequency.The findings demonstrated that the damping value rose as temperature and strain increased,with a maximum value of 0.15.Additionally,the damping value decreased when the frequency increased.Dislocation damping under strain and interfacial damping under temperature served as the two primary damping mechanisms.The increase in the density of dislocation strong pinning points following heat treatment reduced the damping value,which was attributed to the heat treatment enhancement of the interfacial bonding force of the composites.
基金the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(2020R1A2C1A01011131)the Energy Cloud R&D Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science,ICT(2019M3F2A1073164).
文摘Base isolators used in buildings provide both a good acceleration reduction and structural vibration control structures.The base isolators may lose their damping capacity over time due to environmental or dynamic effects.This deterioration of them requires the determination of the maintenance and repair needs and is important for the long-termisolator life.In this study,an artificial intelligence prediction model has been developed to determine the damage and maintenance-repair requirements of isolators as a result of environmental effects and dynamic factors over time.With the developed model,the required damping capacity of the isolator structure was estimated and compared with the previously placed isolator capacity,and the decrease in the damping property was tried to be determined.For this purpose,a data set was created by collecting the behavior of structures with single degrees of freedom(SDOF),different stiffness,damping ratio and natural period isolated from the foundation under far fault earthquakes.The data is divided into 5 different damping classes varying between 10%and 50%.Machine learning model was trained in damping classes with the data on the structure’s response to random seismic vibrations.As a result of the isolator behavior under randomly selected earthquakes,the recorded motion and structural acceleration of the structure against any seismic vibration were examined,and the decrease in the damping capacity was estimated on a class basis.The performance loss of the isolators,which are separated according to their damping properties,has been tried to be determined,and the reductions in the amounts to be taken into account have been determined by class.In the developed prediction model,using various supervised machine learning classification algorithms,the classification algorithm providing the highest precision for the model has been decided.When the results are examined,it has been determined that the damping of the isolator structure with the machine learning method is predicted successfully at a level exceeding 96%,and it is an effective method in deciding whether there is a decrease in the damping capacity.
基金Supports from the National Natural Science Foundation of China(Grant No.12272094,No.52205185 and No.51975123)the Natural Science Foundation of Fujian Province of China(Grant No.2022J01541 and No.2020J05102)the Key Project of National Defence Innovation Zone of Science and Technology Commission of CMC(Grant No.XXX-033-01)。
文摘To explore the wide-frequency damping and vibration-attenuation performances in the application of aerospace components,the cylindrical sandwich shell structure with a gradient core of entangled wire mesh was proposed in this paper.Firstly,the gradient cores of entangled wire mesh in the axial and radial directions were prepared by using an in-house Numerical Control weaving machine,and the metallurgical connection between skin sheets and the gradient core was performed using vacuum brazing.Secondly,to investigate the mechanical properties of cylindrical sandwich shells with axial or radial gradient cores,quasi-static and dynamic mechanical experiments were carried out.The primary evaluations of mechanical properties include secant stiffness,natural frequency,Specific Energy Absorption(SEA),vibration acceleration level,and so on.The results suggest that the vibration-attenuation performance of the sandwich shell is remarkable when the high-density core layer is at the end of the shell or abuts the inner skin.The axial gradient material has almost no influence on the vibration frequencies of the shell,whereas the vibration frequencies increase dramatically when the high-density core layer approaches the skin.Moreover,compared to the conventional sandwich shells,the proposed functional grading cylindrical sandwich shell exhibits more potential in mass reduction,stiffness designing,and energy dissipation.
基金supported by the National Natural Science Foundation of China (Grant No.51805086)。
文摘Strong impact does serious harm to the military industries so it is necessary to choose reasonable cushioning material and design effective buffers to prevent the impact of equipment.Based on the capillary property entangled porous metallic wire materials(EPMWM),this paper designed a composite buffer which uses EPMWM and viscous fluid as cushioning materials under the low-speed impact of the recoil force device of weapon equipment(such as artillery,mortar,etc.).Combined with the capillary model,porosity,hydraulic diameter,maximum pore diameter and pore distribution were used to characterize the pore structure characteristics of EPMWM.The calculation model of the damping force of the composite buffer was established.The low-speed impact test of the composite buffer was conducted.The parameters of the buffer under low-speed impact were identified according to the model,and the nonlinear model of damping force was obtained.The test results show that the composite buffer with EPMWM and viscous fluid can absorb the impact energy from the recoil movement effectively,and provide a new method for the buffer design of weapon equipment(such as artillery,mortar,etc.).
基金Project(51978585)supported by the National Natural Science Foundation,ChinaProject(2022YFB2603404)supported by the National Key Research and Development Program,China+1 种基金Project(U1734207)supported by the High-speed Rail Joint Fund Key Projects of Basic Research,ChinaProject(2023NSFSC1975)supported by the Sichuan Nature and Science Foundation Innovation Research Group Project,China。
文摘The problems associated with vibrations of viaducts and low-frequency structural noise radiation caused by train excitation continue to increase in importance.A new floating-slab track vibration isolator-non-obstructive particle damping-phononic crystal vibration isolator is proposed herein,which uses the particle damping vibration absorption technology and bandgap vibration control theory.The vibration reduction performance of the NOPD-PCVI was analyzed from the perspective of vibration control.The paper explores the structure-borne noise reduction performance of the NOPD-PCVIs installed on different bridge structures under varying service conditions encountered in practical engineering applications.The load transferred to the bridge is obtained from a coupled train-FST-bridge analytical model considering the different structural parameters of bridges.The vibration responses are obtained using the finite element method,while the structural noise radiation is simulated using the frequency-domain boundary element method.Using the particle swarm optimization algorithm,the parameters of the NOPD-PCVI are optimized so that its frequency bandgap matches the dominant bridge structural noise frequency range.The noise reduction performance of the NOPD-PCVIs is compared to the steel-spring isolation under different service conditions.
基金supported in part by the Fundamental Research Funds for the Central Universities under Grant 2682023CX019National Natural Science Foundation of China under Grant U23B6007 and Grant 52307141Sichuan Science and Technology Program under Grant 2024NSFSC0115。
文摘High-frequency oscillation(HFO)of gridconnected wind power generation systems(WPGS)is one of the most critical issues in recent years that threaten the safe access of WPGS to the grid.Ensuring the WPGS can damp HFO is becoming more and more vital for the development of wind power.The HFO phenomenon of wind turbines under different scenarios usually has different mechanisms.Hence,engineers need to acquire the working mechanisms of the different HFO damping technologies and select the appropriate one to ensure the effective implementation of oscillation damping in practical engineering.This paper introduces the general assumptions of WPGS when analyzing HFO,systematically summarizes the reasons for the occurrence of HFO in different scenarios,deeply analyses the key points and difficulties of HFO damping under different scenarios,and then compares the technical performances of various types of HFO suppression methods to provide adequate references for engineers in the application of technology.Finally,this paper discusses possible future research difficulties in the problem of HFO,as well as the possible future trends in the demand for HFO damping.
文摘The application of carbon nanomaterials, particularly graphene and carbon nanotubes, in cement-based composites is highly significant. These materials demonstrate the multifunctionality of carbon and offer extensive possibilities for technological advancements. This research analyzes how the integration of graphene into cement-based composites enhances damping and mechanical properties, thereby contributing to the safety and durability of structures. Research on carbon nanomaterials is ongoing and is expected to continue driving innovation across various industrial sectors, promoting the sustainable development of building materials.
文摘This paper conducted experimental studies on the damping and mechanical properties of carbon nanotube-nanosilica-cement composite materials with different carbon nanotube contents. The damping and mechanical properties enhancement mechanisms were analyzed and compared through the porosity structure test, XRD analysis, and scanning electron microscope observation. The results show that the introduction of nanosilica significantly improves the dispersion of carbon nanotubes in the cement matrix. At the same time, the addition of nanosilica not only effectively reduces the critical pore size and average pore size of the cement composite material, but also exhibits good synergistic effects with carbon nanotubes, which can significantly optimize the pore structure. Finally, a rationalization suggestion for the co-doping of nanosilica and carbon nanotubes was given to achieve a significant increase in the flexural strength, compressive strength and loss factor of cement-based materials.
文摘Objective:To evaluate the efficacy and safety of a Chinese medicine(CM)Modified Qufeng Runmian Powder(加减祛风润面散,MQFRMP)for the treatment of acne vulgaris with CM syndromes of dampness and blood stasis.Methods:In this multicenter,randomized,double-blind,placebo-controlled clinical trial,220 acne vulgaris patients with CM syndrome of dampness and blood stasis were included and randomly assigned using a central area group random design to receive either MQFRMP or the placebo,with 110 cases in each group.MQFRMP or a placebo at 145 g/bag were administered once daily for 4 weeks,respectively.The primary index of efficacy was the effective rate according to the acne severity score(ASS).The secondary indices of efficacy included the changes in the dermatology life quality index(DLQI)score,VISIA scores(spots,pores,brown spots,porphyrins and red areas)and skin assessment(skin p H,sebum amount and hydration)according to a SOFT skin multianalyzer.Results:(1)Follow-up:a total of 204 patients completed the follow-up,with 103 in the treatment group and 101 in the control group.(2)Effective rate:the total effective rate of the treatment group was significantly higher than the control group[83.5%(86/103)vs.31.7%(32/101),P<0.01)]with 95%confidence interval of 39.3%–66.4%.(3)DLQI:DLQI scores were significantly decreased the treatment and control groups(both P<0.01),but the treatment group was more obvious than the placebo group(P<0.01).(4)VISIA scores:the scores of spots,brown spots and red areas in the treatment group decreased compared with baseline(P<0.05).In the control group,the scores of brown spots and pores decreased compared with baseline(P<0.05).The improvement was more obvious in the treatment group than in the control group for all items(P<0.05).(5)Skin assessment:the p H and sebum score in the both groups decreased drastically compared with the baseline(all P<0.01),however,the improvement was more obvious in the treatment group than in the control group(P<0.01).The hydration amount in the two groups showed no statistically significant difference compared with the baseline(both P>0.05).(6)Safety:two cases of mild drug allergy were observed in the treatment group.Conclusion:MQFRMP was effective and safe for the treatment of acne vulgaris with syndromes of dampness and blood stasis.(No.ChiCTR1900020479).