Background:The European Society for Medical Oncology(ESMO)guidelines are among the most comprehensive and widely used clinical practice guidelines(CPGs)globally.However,the level of scientific evidence supporting ESMO...Background:The European Society for Medical Oncology(ESMO)guidelines are among the most comprehensive and widely used clinical practice guidelines(CPGs)globally.However,the level of scientific evidence supporting ESMO CPG recommendations has not been systematically investigated.This study assessed ESMO CPG levels of evidence(LOE)and grades of recommendations(GOR),as well as their trends over time across various cancer settings.Methods:We manually extracted every recommendation with the Infectious Diseases Society of America(IDSA)classification from each CPG.We examined the distribution of LOE and GOR in all available ESMO CPG guidelines across different topics and cancer types.Results:Among the 1,823 recommendations in the current CPG,30%were classified as LOEⅠ,and 43%were classified as GOR A.Overall,there was a slight decrease in LOEⅠ(−2%)and an increase in the proportion of GOR A(+1%)in the current CPG compared to previous versions.The proportion of GOR A recommendations based on higher levels of evidence such as randomized trials(LOEⅠ–Ⅱ)shows a decrease(71%vs.63%,p=0.009)while recommendations based on lower levels of evidence(LOEⅢ–Ⅴ)show an increase(29%vs.37%,p=0.01)between previous and current version.In the current versions,the highest proportion of LOEⅠ(42%)was found in recommendations related to pharmacotherapy,while the highest proportion of GOR A recommendations was found in the areas of pathology(50%)and diagnostic(50%)recommendations.Significant variability in LOEⅠand GOR A recommendations and their changes over time was observed across different cancer types.Conclusion:One-third of the current ESMO CPG recommendations are supported by the highest level of evidence.More well-designed randomized clinical trials are needed to increase the proportion of LOEⅠand GOR A recommendations,ultimately leading to improved outcomes for cancer patients.展开更多
By analyzing the correlation between courses in students’grades,we can provide a decision-making basis for the revision of courses and syllabi,rationally optimize courses,and further improve teaching effects.With the...By analyzing the correlation between courses in students’grades,we can provide a decision-making basis for the revision of courses and syllabi,rationally optimize courses,and further improve teaching effects.With the help of IBM SPSS Modeler data mining software,this paper uses Apriori algorithm for association rule mining to conduct an in-depth analysis of the grades of nursing students in Shandong College of Traditional Chinese Medicine,and to explore the correlation between professional basic courses and professional core courses.Lastly,according to the detailed analysis of the mining results,valuable curriculum information will be found from the actual teaching data.展开更多
This study investigated the aroma-active compounds and compared the differences of three different grades of sesame-flavor Baijiu by headspace solid-phase microextraction(HS-SPME)coupled with gas chromatography-olfact...This study investigated the aroma-active compounds and compared the differences of three different grades of sesame-flavor Baijiu by headspace solid-phase microextraction(HS-SPME)coupled with gas chromatography-olfactometry-mass spectrometry(GC-O-MS).A total of 54 aroma-active compounds were detected.Principal component analysis showed that JZ1,JZ2,and JZ3 were well separated from each other.JZ1 as the premium-grade Baijiu had the highest aroma intensities,concentrations.According to aroma intensities and concentrations,dimethyl trisulfide,butanoic acid,phenylacetaldehyde,2-furylmethanethiol,ethyl hexanoate,2,6-dimethylpyrazine,etc.could be potentially applied as volatile makers to distinguish the three different grades of sesame-flavor Baijiu as their significant difference(P<0.05)in three Baijiu samples.Roasted aroma had the significant difference(P<0.05)in three sample base on aroma profiles.Meanwhile,2-furylmethanethiol,2,6-dimethylpyrazine were related to the roasted aroma,they may be had a significant contribution to the differences of three different grades of sesame-flavor Baijiu.This study has provided a comprehensive understanding of the differences of three different grades of sesame-flavor Baijiu.展开更多
目的运用循证医学方法对腕踝针干预术后疼痛的疗效和安全性进行系统评价和Grade评价。方法计算机检索中国知网、万方、维普、中国生物医学文献数据库、PubMed、Embase、Web of Science、Cochrane Library中关于腕踝针干预术后疼痛的随...目的运用循证医学方法对腕踝针干预术后疼痛的疗效和安全性进行系统评价和Grade评价。方法计算机检索中国知网、万方、维普、中国生物医学文献数据库、PubMed、Embase、Web of Science、Cochrane Library中关于腕踝针干预术后疼痛的随机对照试验,检索时限为建库至2023年10月。采用RevMan 5.4软件进行Meta分析。结果纳入23篇文献,共计1968例患者,Meta分析结果显示,与常规治疗相比,腕踝针能够提高术后疼痛患者的总有效率[OR=4.42,95%CI(2.60,7.50),P<0.001],术后镇痛泵药量使用减少[MD=-9.03,95%CI(-12.09,-5.98),P<0.001],术后疼痛评分降低[MD=-1.39,95%CI(-1.68,-1.09),P<0.001],可减少不良反应发生率[RR=0.40,95%CI(0.32,0.48),P<0.001]以及临床满意度[OR=3.94,95%CI(2.40,6.48),P<0.001]。Grade证据分级结果显示:总有效率、不良反应发生率和临床满意度3项结局指标为中等质量证据,VAS评分指标为低质量证据,镇痛泵药量使用指标为极低质量证据。结论腕踝针可提高总有效率,减少术后镇痛药用量,不良反应少,安全性高,为患者提供了一种安全有效的镇痛方式。展开更多
目的系统评价补肾方剂改善高龄女性自然妊娠结局的临床疗效和安全性。方法检索中国知网、万方数据库、维普数据库、SinoMed、PubMed、Web of Science、Cochrane Library、Embase等数据库建库至2022年6月收录的补肾方剂改善高龄女性自然...目的系统评价补肾方剂改善高龄女性自然妊娠结局的临床疗效和安全性。方法检索中国知网、万方数据库、维普数据库、SinoMed、PubMed、Web of Science、Cochrane Library、Embase等数据库建库至2022年6月收录的补肾方剂改善高龄女性自然妊娠结局的随机对照研究(RCT)。运用偏倚风险工具进行质量评估,使用RevMan软件进行Meta分析。结果共纳入14篇RCT。Meta分析结果显示:补肾方剂联合西药治疗在提高妊娠率[RR=1.71,95%CI(1.45,2.01),P<0.00001]、降低卵泡刺激素(FSH)水平[SMD=-1.63,95%CI(-2.84,-0.43),P=0.008]、提高雌二醇(E_(2))水平[SMD=3.97,95%CI(1.76,6.17),P=0.0004]、增加排卵期子宫内膜厚度[SMD=2.12,95%CI(1.07,3.18),P<0.0001]方面均优于西药组;且补肾方剂单独使用在提高妊娠率[RR=1.94,95%CI(1.31,2.88),P=0.001]、降低FSH水平[SMD=-0.48,95%CI(-0.74,-0.22),P=0.0003]方面也具有显著疗效。结论与西医治疗比较,补肾方剂可以显著改善高龄女性自然妊娠结局,且不良反应较少,但仍需更多高质量、大样本、多中心的RCT予以验证。展开更多
目的:评价温针灸治疗原发性痛经的有效性和安全性。方法:根据PRISMA指南进行系统综述和荟萃分析。收集PubMed、Web of Science、EMBASE、Cochrane Library、中国知网、维普、万方、中国生物医学数据库自建库至2023年5月的随机对照试验...目的:评价温针灸治疗原发性痛经的有效性和安全性。方法:根据PRISMA指南进行系统综述和荟萃分析。收集PubMed、Web of Science、EMBASE、Cochrane Library、中国知网、维普、万方、中国生物医学数据库自建库至2023年5月的随机对照试验。使用Review Manager 5.4对所有获得的数据进行分析。结果:温针灸治疗原发性痛经在提高临床疗效{风险比(RR)=1.21,95%置信区间(CI)[1.16,1.25],P<0.00001},改善阻力指数(RI){均数差(MD)=-0.14,95%CI[-0.19,-0.08],P<0.00001}、搏动指数(PI)(MD=-0.55,95%CI[-0.69,-0.40],P<0.00001)、β-内啡肽(β-EP){标准化均数差(SMD)=1.36,95%CI[0.90,1.82],P<0.00001}、痛经证候积分(MD=-1.82,95%CI[-2.77,-0.87],P=0.0002)、疼痛视觉模拟评分法(VAS)评分(MD=-1.16,95%CI[-1.48,-0.83],P<0.00001)方面的作用优于单独的常规治疗,并且在不良反应发生率(P=0.01)方面低于对照组。证据质量等级评价结果显示临床疗效为中级,其他多为低级。结论:温针灸治疗原发性痛经的疗效明确,并且具有一定的安全性。展开更多
Based on the hourly precipitation data from 4 observation stations of Xining City from June to September during 2005-2011,the temporal and spatial distribution characteristics of short-time precipitation were analyzed...Based on the hourly precipitation data from 4 observation stations of Xining City from June to September during 2005-2011,the temporal and spatial distribution characteristics of short-time precipitation were analyzed.The results show that the precipitation distribution in Xining region exhibited the less-more-less trend from southwest to northeast,while the torrential rain gradually increased from the northwest and southwest to the middle.The hourly general precipitation in Xining region had obviously seasonal characteristics,and its annual distribution showed wavy changes,but the annual variation of short-time heavy precipitation and rainstorm was very obvious.Furthermore,short-time heavy precipitation was concentrated from 18:00 to 24:00,followed by 03:00-07:00 on the following day.The occurrence time of short-time rainstorm accorded with short-time heavy precipitation.It offers a useful reference for the accurate and timely short-term forecast.展开更多
The combination of online teaching and traditional offline teaching can maximize the advantages of both.Based on the blended teaching of English Reading course,39 students were selected as the research subjects to stu...The combination of online teaching and traditional offline teaching can maximize the advantages of both.Based on the blended teaching of English Reading course,39 students were selected as the research subjects to study the relationship between their online learning attitudes and their grades in the final examination.Judged from the number of times for each student to download teaching resources,the number of assignments submitted online,and the quality of the submitted assignments,each student’s attitude toward online learning was examined comprehensively,and a correlation analysis was conducted through SPSS Statistics 21.0 to explore the influence of online learning attitude on English reading performance.Through data collection and analysis of the online learning attitudes over a 16-week period,a significant positive correlation was found between the online learning attitudes and the English reading grades,indicating that the online learning attitude in the blended learning model plays a crucial role in improving the English reading skill,and students should maintain a positive attitude toward online teaching in blended learning.展开更多
Through equilibrium and non-equilibrium molecular dynamics simulations,we have demonstrated the inhibitory effect of composition graded interface on thermal transport behavior in lateral heterostructures.Specifically,...Through equilibrium and non-equilibrium molecular dynamics simulations,we have demonstrated the inhibitory effect of composition graded interface on thermal transport behavior in lateral heterostructures.Specifically,we investigated the influence of composition gradient length and heterogeneous particles at the silicene/germanene(SIL/GER)heterostructure interface on heat conduction.Our results indicate that composition graded interface at the interface diminishes the thermal conductivity of the heterostructure,with a further reduction observed as the length increases,while the effect of the heterogeneous particles can be considered negligible.To unveil the influence of composition graded interface on thermal transport,we conducted phonon analysis and identified the presence of phonon localization within the interface composition graded region.Through these analyses,we have determined that the decrease in thermal conductivity is correlated with phonon localization within the heterostructure,where a stronger degree of phonon localization signifies poorer thermal conductivity in the material.Our research findings not only contribute to understanding the impact of interface gradient-induced phonon localization on thermal transport but also offer insights into the modulation of thermal conductivity in heterostructures.展开更多
In this work,we numerically study the hydrodynamic permeability of new-generation artificial porous materials used as scaffolds for cell growth in a perfusion bioreactor.We consider two popular solid matrix designs ba...In this work,we numerically study the hydrodynamic permeability of new-generation artificial porous materials used as scaffolds for cell growth in a perfusion bioreactor.We consider two popular solid matrix designs based on triply periodic minimal surfaces,the Schwarz P(primitive)and D(diamond)surfaces,which enable the creation of materials with controlled porosity gradients.The latter property is crucial for regulating the shear stress field in the pores of the scaffold,which makes it possible to control the intensity of cell growth.The permeability of functionally graded materials is studied within the framework of both a microscopic approach based on the Navier-Stokes equation and an averaged description of the liquid filtration through a porous medium based on the equations of the Darcy or Forchheimer models.We calculate the permeability coefficients for both types of solid matrices formed by Schwarz surfaces,study their properties concerning forward and reverse fluid flows,and determine the ranges of Reynolds number for which the description within the Darcy or Forchheimer model is applicable.Finally,we obtain a shear stress field that varies along the sample,demonstrating the ability to tune spatially the rate of tissue growth.展开更多
Based on the generalized Hamilton's principle,the nonlinear governing equation of an axially functionally graded(AFG)pipe is established.The non-trivial equilibrium configuration is superposed by the modal functio...Based on the generalized Hamilton's principle,the nonlinear governing equation of an axially functionally graded(AFG)pipe is established.The non-trivial equilibrium configuration is superposed by the modal functions of a simply supported beam.Via the direct multi-scale method,the response and stability boundary to the pulsating fluid velocity are solved analytically and verified by the differential quadrature element method(DQEM).The influence of Young's modulus gradient on the parametric resonance is investigated in the subcritical and supercritical regions.In general,the pipe in the supercritical region is more sensitive to the pulsating excitation.The nonlinearity changes from hard to soft,and the non-trivial equilibrium configuration introduces more frequency components to the vibration.Besides,the increasing Young's modulus gradient improves the critical pulsating flow velocity of the parametric resonance,and further enhances the stability of the system.In addition,when the temperature increases along the axial direction,reducing the gradient parameter can enhance the response asymmetry.This work further complements the theoretical analysis of pipes conveying pulsating fluid.展开更多
This study proposes an effective method to enhance the accuracy of the Differential Quadrature Method(DQM)for calculating the dynamic characteristics of functionally graded beams by improving the form of discrete node...This study proposes an effective method to enhance the accuracy of the Differential Quadrature Method(DQM)for calculating the dynamic characteristics of functionally graded beams by improving the form of discrete node distribution.Firstly,based on the first-order shear deformation theory,the governing equation of free vibration of a functionally graded beam is transformed into the eigenvalue problem of ordinary differential equations with respect to beam axial displacement,transverse displacement,and cross-sectional rotation angle by considering the effects of shear deformation and rotational inertia of the beam cross-section.Then,ignoring the shear deformation of the beam section and only considering the effect of the rotational inertia of the section,the governing equation of the beam is transformed into the eigenvalue problem of ordinary differential equations with respect to beam transverse displacement.Based on the differential quadrature method theory,the eigenvalue problem of ordinary differential equations is transformed into the eigenvalue problem of standard generalized algebraic equations.Finally,the first several natural frequencies of the beam can be calculated.The feasibility and accuracy of the improved DQM are verified using the finite element method(FEM)and combined with the results of relevant literature.展开更多
Limestone is one of the essential raw materials in the cement,paint,steel,ceramic,glass,chemical,pharmaceutical,paper,and fertilizer industries.In India,only 8%of the limestone resources are placed under the reserve c...Limestone is one of the essential raw materials in the cement,paint,steel,ceramic,glass,chemical,pharmaceutical,paper,and fertilizer industries.In India,only 8%of the limestone resources are placed under the reserve category,of which 97%is of cement grade.Thus,India depends on imports to bridge the demand‐supply gap of steel,blast furnace,and chemical‐grade limestone.Efforts of Geological Survey of India(GSI)to locate alternate sources for limestone led to the discovery of enormous quantities of carbonate minerals called limemud from the continental shelf margin of the west coast of India.GSI carried out systematic studies to explore the nature of the disposition,quality,quantity,and suitability of the offshore limemud for various industrial applications.A preliminary estimate of resources using high‐resolution subbottom profiling and sediment core sample studies established the occurrence of more than 172 billion tonnes of high‐grade(The content of CaCO3 is greater than 80 wt%)limemud in 0.4–28.0m thick stratified sediment layers spread over an area of 18000 km2.Chemical,physical,mineralogical,beneficiation,and agglomeration studies found the offshore limemud as a potential replacement for limestone in the cement,filler,blast furnace,steel melting shop,lime production,paint,and Grade‐I steel industries.An assessment of mining and transportation costs indicates that the offshore limemud(USD 5–6/ton)is more cost‐effective than that imported from other countries(USD16‐18/ton).With several advantageous factors like low impurity,mode of occurrence in overburden‐free stratified form,fine‐grained slurry nature,and shallow water depth,sustainable mining of offshore limemud could be a future reality with controllable technological,economic,and environmental challenges.展开更多
文摘Background:The European Society for Medical Oncology(ESMO)guidelines are among the most comprehensive and widely used clinical practice guidelines(CPGs)globally.However,the level of scientific evidence supporting ESMO CPG recommendations has not been systematically investigated.This study assessed ESMO CPG levels of evidence(LOE)and grades of recommendations(GOR),as well as their trends over time across various cancer settings.Methods:We manually extracted every recommendation with the Infectious Diseases Society of America(IDSA)classification from each CPG.We examined the distribution of LOE and GOR in all available ESMO CPG guidelines across different topics and cancer types.Results:Among the 1,823 recommendations in the current CPG,30%were classified as LOEⅠ,and 43%were classified as GOR A.Overall,there was a slight decrease in LOEⅠ(−2%)and an increase in the proportion of GOR A(+1%)in the current CPG compared to previous versions.The proportion of GOR A recommendations based on higher levels of evidence such as randomized trials(LOEⅠ–Ⅱ)shows a decrease(71%vs.63%,p=0.009)while recommendations based on lower levels of evidence(LOEⅢ–Ⅴ)show an increase(29%vs.37%,p=0.01)between previous and current version.In the current versions,the highest proportion of LOEⅠ(42%)was found in recommendations related to pharmacotherapy,while the highest proportion of GOR A recommendations was found in the areas of pathology(50%)and diagnostic(50%)recommendations.Significant variability in LOEⅠand GOR A recommendations and their changes over time was observed across different cancer types.Conclusion:One-third of the current ESMO CPG recommendations are supported by the highest level of evidence.More well-designed randomized clinical trials are needed to increase the proportion of LOEⅠand GOR A recommendations,ultimately leading to improved outcomes for cancer patients.
文摘By analyzing the correlation between courses in students’grades,we can provide a decision-making basis for the revision of courses and syllabi,rationally optimize courses,and further improve teaching effects.With the help of IBM SPSS Modeler data mining software,this paper uses Apriori algorithm for association rule mining to conduct an in-depth analysis of the grades of nursing students in Shandong College of Traditional Chinese Medicine,and to explore the correlation between professional basic courses and professional core courses.Lastly,according to the detailed analysis of the mining results,valuable curriculum information will be found from the actual teaching data.
基金supported by the National Natural Science Foundation of China (32172340)
文摘This study investigated the aroma-active compounds and compared the differences of three different grades of sesame-flavor Baijiu by headspace solid-phase microextraction(HS-SPME)coupled with gas chromatography-olfactometry-mass spectrometry(GC-O-MS).A total of 54 aroma-active compounds were detected.Principal component analysis showed that JZ1,JZ2,and JZ3 were well separated from each other.JZ1 as the premium-grade Baijiu had the highest aroma intensities,concentrations.According to aroma intensities and concentrations,dimethyl trisulfide,butanoic acid,phenylacetaldehyde,2-furylmethanethiol,ethyl hexanoate,2,6-dimethylpyrazine,etc.could be potentially applied as volatile makers to distinguish the three different grades of sesame-flavor Baijiu as their significant difference(P<0.05)in three Baijiu samples.Roasted aroma had the significant difference(P<0.05)in three sample base on aroma profiles.Meanwhile,2-furylmethanethiol,2,6-dimethylpyrazine were related to the roasted aroma,they may be had a significant contribution to the differences of three different grades of sesame-flavor Baijiu.This study has provided a comprehensive understanding of the differences of three different grades of sesame-flavor Baijiu.
文摘目的运用循证医学方法对腕踝针干预术后疼痛的疗效和安全性进行系统评价和Grade评价。方法计算机检索中国知网、万方、维普、中国生物医学文献数据库、PubMed、Embase、Web of Science、Cochrane Library中关于腕踝针干预术后疼痛的随机对照试验,检索时限为建库至2023年10月。采用RevMan 5.4软件进行Meta分析。结果纳入23篇文献,共计1968例患者,Meta分析结果显示,与常规治疗相比,腕踝针能够提高术后疼痛患者的总有效率[OR=4.42,95%CI(2.60,7.50),P<0.001],术后镇痛泵药量使用减少[MD=-9.03,95%CI(-12.09,-5.98),P<0.001],术后疼痛评分降低[MD=-1.39,95%CI(-1.68,-1.09),P<0.001],可减少不良反应发生率[RR=0.40,95%CI(0.32,0.48),P<0.001]以及临床满意度[OR=3.94,95%CI(2.40,6.48),P<0.001]。Grade证据分级结果显示:总有效率、不良反应发生率和临床满意度3项结局指标为中等质量证据,VAS评分指标为低质量证据,镇痛泵药量使用指标为极低质量证据。结论腕踝针可提高总有效率,减少术后镇痛药用量,不良反应少,安全性高,为患者提供了一种安全有效的镇痛方式。
文摘目的系统评价补肾方剂改善高龄女性自然妊娠结局的临床疗效和安全性。方法检索中国知网、万方数据库、维普数据库、SinoMed、PubMed、Web of Science、Cochrane Library、Embase等数据库建库至2022年6月收录的补肾方剂改善高龄女性自然妊娠结局的随机对照研究(RCT)。运用偏倚风险工具进行质量评估,使用RevMan软件进行Meta分析。结果共纳入14篇RCT。Meta分析结果显示:补肾方剂联合西药治疗在提高妊娠率[RR=1.71,95%CI(1.45,2.01),P<0.00001]、降低卵泡刺激素(FSH)水平[SMD=-1.63,95%CI(-2.84,-0.43),P=0.008]、提高雌二醇(E_(2))水平[SMD=3.97,95%CI(1.76,6.17),P=0.0004]、增加排卵期子宫内膜厚度[SMD=2.12,95%CI(1.07,3.18),P<0.0001]方面均优于西药组;且补肾方剂单独使用在提高妊娠率[RR=1.94,95%CI(1.31,2.88),P=0.001]、降低FSH水平[SMD=-0.48,95%CI(-0.74,-0.22),P=0.0003]方面也具有显著疗效。结论与西医治疗比较,补肾方剂可以显著改善高龄女性自然妊娠结局,且不良反应较少,但仍需更多高质量、大样本、多中心的RCT予以验证。
基金Supported by the Key Research and Development and Transformation Project of Science and Technology Department of Qinghai Province in 2021(2021-SF-141-2).
文摘Based on the hourly precipitation data from 4 observation stations of Xining City from June to September during 2005-2011,the temporal and spatial distribution characteristics of short-time precipitation were analyzed.The results show that the precipitation distribution in Xining region exhibited the less-more-less trend from southwest to northeast,while the torrential rain gradually increased from the northwest and southwest to the middle.The hourly general precipitation in Xining region had obviously seasonal characteristics,and its annual distribution showed wavy changes,but the annual variation of short-time heavy precipitation and rainstorm was very obvious.Furthermore,short-time heavy precipitation was concentrated from 18:00 to 24:00,followed by 03:00-07:00 on the following day.The occurrence time of short-time rainstorm accorded with short-time heavy precipitation.It offers a useful reference for the accurate and timely short-term forecast.
文摘The combination of online teaching and traditional offline teaching can maximize the advantages of both.Based on the blended teaching of English Reading course,39 students were selected as the research subjects to study the relationship between their online learning attitudes and their grades in the final examination.Judged from the number of times for each student to download teaching resources,the number of assignments submitted online,and the quality of the submitted assignments,each student’s attitude toward online learning was examined comprehensively,and a correlation analysis was conducted through SPSS Statistics 21.0 to explore the influence of online learning attitude on English reading performance.Through data collection and analysis of the online learning attitudes over a 16-week period,a significant positive correlation was found between the online learning attitudes and the English reading grades,indicating that the online learning attitude in the blended learning model plays a crucial role in improving the English reading skill,and students should maintain a positive attitude toward online teaching in blended learning.
基金Project supported by the National Natural Science Foundation of China (Grant No.12104291)。
文摘Through equilibrium and non-equilibrium molecular dynamics simulations,we have demonstrated the inhibitory effect of composition graded interface on thermal transport behavior in lateral heterostructures.Specifically,we investigated the influence of composition gradient length and heterogeneous particles at the silicene/germanene(SIL/GER)heterostructure interface on heat conduction.Our results indicate that composition graded interface at the interface diminishes the thermal conductivity of the heterostructure,with a further reduction observed as the length increases,while the effect of the heterogeneous particles can be considered negligible.To unveil the influence of composition graded interface on thermal transport,we conducted phonon analysis and identified the presence of phonon localization within the interface composition graded region.Through these analyses,we have determined that the decrease in thermal conductivity is correlated with phonon localization within the heterostructure,where a stronger degree of phonon localization signifies poorer thermal conductivity in the material.Our research findings not only contribute to understanding the impact of interface gradient-induced phonon localization on thermal transport but also offer insights into the modulation of thermal conductivity in heterostructures.
文摘In this work,we numerically study the hydrodynamic permeability of new-generation artificial porous materials used as scaffolds for cell growth in a perfusion bioreactor.We consider two popular solid matrix designs based on triply periodic minimal surfaces,the Schwarz P(primitive)and D(diamond)surfaces,which enable the creation of materials with controlled porosity gradients.The latter property is crucial for regulating the shear stress field in the pores of the scaffold,which makes it possible to control the intensity of cell growth.The permeability of functionally graded materials is studied within the framework of both a microscopic approach based on the Navier-Stokes equation and an averaged description of the liquid filtration through a porous medium based on the equations of the Darcy or Forchheimer models.We calculate the permeability coefficients for both types of solid matrices formed by Schwarz surfaces,study their properties concerning forward and reverse fluid flows,and determine the ranges of Reynolds number for which the description within the Darcy or Forchheimer model is applicable.Finally,we obtain a shear stress field that varies along the sample,demonstrating the ability to tune spatially the rate of tissue growth.
基金Project supported by the National Natural Science Foundation of China (Nos.12002195 and 12372015)the National Science Fund for Distinguished Young Scholars of China (No.12025204)the Program of Shanghai Municipal Education Commission of China (No.2019-01-07-00-09-E00018)。
文摘Based on the generalized Hamilton's principle,the nonlinear governing equation of an axially functionally graded(AFG)pipe is established.The non-trivial equilibrium configuration is superposed by the modal functions of a simply supported beam.Via the direct multi-scale method,the response and stability boundary to the pulsating fluid velocity are solved analytically and verified by the differential quadrature element method(DQEM).The influence of Young's modulus gradient on the parametric resonance is investigated in the subcritical and supercritical regions.In general,the pipe in the supercritical region is more sensitive to the pulsating excitation.The nonlinearity changes from hard to soft,and the non-trivial equilibrium configuration introduces more frequency components to the vibration.Besides,the increasing Young's modulus gradient improves the critical pulsating flow velocity of the parametric resonance,and further enhances the stability of the system.In addition,when the temperature increases along the axial direction,reducing the gradient parameter can enhance the response asymmetry.This work further complements the theoretical analysis of pipes conveying pulsating fluid.
基金Anhui Provincial Natural Science Foundation(2308085QD124)Anhui Province University Natural Science Research Project(GrantNo.2023AH050918)The University Outstanding Youth Talent Support Program of Anhui Province.
文摘This study proposes an effective method to enhance the accuracy of the Differential Quadrature Method(DQM)for calculating the dynamic characteristics of functionally graded beams by improving the form of discrete node distribution.Firstly,based on the first-order shear deformation theory,the governing equation of free vibration of a functionally graded beam is transformed into the eigenvalue problem of ordinary differential equations with respect to beam axial displacement,transverse displacement,and cross-sectional rotation angle by considering the effects of shear deformation and rotational inertia of the beam cross-section.Then,ignoring the shear deformation of the beam section and only considering the effect of the rotational inertia of the section,the governing equation of the beam is transformed into the eigenvalue problem of ordinary differential equations with respect to beam transverse displacement.Based on the differential quadrature method theory,the eigenvalue problem of ordinary differential equations is transformed into the eigenvalue problem of standard generalized algebraic equations.Finally,the first several natural frequencies of the beam can be calculated.The feasibility and accuracy of the improved DQM are verified using the finite element method(FEM)and combined with the results of relevant literature.
基金Geological Survey of India(Data collected as part of annual field programme of Geological Survey of India,Ministry of Mines,Government of India)。
文摘Limestone is one of the essential raw materials in the cement,paint,steel,ceramic,glass,chemical,pharmaceutical,paper,and fertilizer industries.In India,only 8%of the limestone resources are placed under the reserve category,of which 97%is of cement grade.Thus,India depends on imports to bridge the demand‐supply gap of steel,blast furnace,and chemical‐grade limestone.Efforts of Geological Survey of India(GSI)to locate alternate sources for limestone led to the discovery of enormous quantities of carbonate minerals called limemud from the continental shelf margin of the west coast of India.GSI carried out systematic studies to explore the nature of the disposition,quality,quantity,and suitability of the offshore limemud for various industrial applications.A preliminary estimate of resources using high‐resolution subbottom profiling and sediment core sample studies established the occurrence of more than 172 billion tonnes of high‐grade(The content of CaCO3 is greater than 80 wt%)limemud in 0.4–28.0m thick stratified sediment layers spread over an area of 18000 km2.Chemical,physical,mineralogical,beneficiation,and agglomeration studies found the offshore limemud as a potential replacement for limestone in the cement,filler,blast furnace,steel melting shop,lime production,paint,and Grade‐I steel industries.An assessment of mining and transportation costs indicates that the offshore limemud(USD 5–6/ton)is more cost‐effective than that imported from other countries(USD16‐18/ton).With several advantageous factors like low impurity,mode of occurrence in overburden‐free stratified form,fine‐grained slurry nature,and shallow water depth,sustainable mining of offshore limemud could be a future reality with controllable technological,economic,and environmental challenges.