Objective:To assess the effectiveness and adverse drug reactions of all-oral regimens for patients with multidrug-resistant tuberculosis.Methods:This retrospective study was conducted at 10 Programmatic Management of ...Objective:To assess the effectiveness and adverse drug reactions of all-oral regimens for patients with multidrug-resistant tuberculosis.Methods:This retrospective study was conducted at 10 Programmatic Management of Drug Resistant Tuberculosis sites in Punjab province of Pakistan.Patients receiving treatment for drug resistant tuberculosis from July 2019 to December 2020 with at least interim result i.e.6th month culture conversion or final outcomes(cured,complete,lost to follow-up,failure,death)available,were included in the study.Data was extracted from electronic data management system.For the reporting and management of adverse drug events,active tuberculosis drug safety monitoring and management was implemented across all sites.All the data was analyzed using SPSS version 22.Results:Out of 947 drug resistant tuberculosis patients included in this study,579(68%)of the patients had final outcomes available.Of these,384(67.9%)successfully completed their treatment.Out of 368(32%)patients who had their interim results available,all had their 6th month culture negative.Combining new medications was thought to result in serious adverse outcomes such as QT prolongation.However,this study did not record any severe adverse events among patients.Conclusions:All-oral regimens formulation guided by overall treatment effectiveness resulted in treatment outcomes comparable to those obtained with traditional injectable treatment.展开更多
Objective:To explore the clinical effect of long-term aerobic exercise combined with resistance training in patients with myocardial ischemia caused by coronary heart disease and its influence on cardiac function, exe...Objective:To explore the clinical effect of long-term aerobic exercise combined with resistance training in patients with myocardial ischemia caused by coronary heart disease and its influence on cardiac function, exercise endurance and quality of life. Methods:100 patients with myocardial ischemia caused by coronary heart disease from January 2017 to January 2019 were randomly divided into control group (n = 50 cases) and observation group (n = 50 cases). The control group was given resistance training, while the observation group was combined with long-term aerobic exercise on the basis of the control group. The two groups were treated for 3 months. The cardiac function, exercise endurance and quality of life were compared between the two groups. Results:The levels of IVST (8.20+1.32) mm, LVDD (46.43+4.13) mm and LVSD (32.59+3.15) mm in the observation group were lower than those in the control group at 3 months after treatment. The level of LVEF (67.49+5.77)% in the observation group was higher than that in the control group at 3 months after treatment. The difference between the two groups was significant (P<0.05). The ET (55.42+2.9) in the observation group was higher than that in the control group (P<0.05). 2) The levels of ng/L and TXB2 (93.23 + 6.26) ng/L were significantly lower than those of the control group, and the difference between the two groups was statistically significant (P<0.05). The 6-minute walking distance (561.25 +43.64) m and the quality of life score (95.31 +6.39) in the observation group were higher than those in the control group 3 months after treatment, and the difference between the two groups was statistically significant (P<0.05). Conclusions:Long-term aerobic exercise combined with resistance training can improve cardiac function, exercise tolerance and quality of life in patients with myocardial ischemia caused by coronary heart disease, which is worthy of popularization and application.展开更多
The service performance of heat resistance steels is largely determined by the precipitation kinetics.The nucleation-growth-coarsening behaviors of precipitates in G115 martensitic heat resistance steel during long-te...The service performance of heat resistance steels is largely determined by the precipitation kinetics.The nucleation-growth-coarsening behaviors of precipitates in G115 martensitic heat resistance steel during long-term aging at 650℃ have been systemically investigated.The microstructural characteristics,precipitate morphology and alloying element distribution were studied by scanning electron microscopy,transmission electron microscopy and scanning transmission electron microscopy.The lognormal distribution fitting combined with the multiple regression analysis was adopted to evaluate the precipitate size distributions.Laves phase has longer incubation time,and its coarsening rate is almost one order of magnitude higher in comparison with that of M_(23)C_(6) carbide.Furthermore,the nucleation rate,number density,average radius,and volume fraction of two precipitates are simulated based on the classical nucleation theory and the modified Langer-Schwartz model.The precipitation behavior of Laves phase can be well explained with the Fe-W system as the interfacial energy takes 0.10 J/m^(2).In contrast,the simulation results of M_(23)C_(6) carbide in the Fe-Cr-C system are significantly overestimated,which results from the inhibitory effect of boron on coarsening.展开更多
The pull-out capacities for soil nailing systems comprising of one single 29 mm diameter(type A) and four 16 mm diameter(type B) rebars with grouted cement were examined.A field test and numerical analysis for the typ...The pull-out capacities for soil nailing systems comprising of one single 29 mm diameter(type A) and four 16 mm diameter(type B) rebars with grouted cement were examined.A field test and numerical analysis for the type A and type B systems were carried out to investigate the pull-out capacities and the slope stability reinforcement efficiency in soil and rock slopes.The results of the pull-out tests show the mobilized shear force and load transfer characteristics with respect to soil depth.The load-displacement relationship was examined for both type A and type B systems.Slope stability analyses were carried out to study the relationships between soil and nail reinforcement and bending stiffness as well as combined axial tension and shear forces.Factors of safety were calculated in relation to the number of nails and their outside diameters.Both soil and rock slopes were included in this evaluation.展开更多
A convenient approach was proposed by which to evaluate and monitor the permeability of a rock fracture by verifying the quantitative correlation between the electrical resistivity and permeability at laboratory scale...A convenient approach was proposed by which to evaluate and monitor the permeability of a rock fracture by verifying the quantitative correlation between the electrical resistivity and permeability at laboratory scale.For this purpose,an electrical resistivity measurement system was applied to the laboratory experiments using artificial cells with the shape of a single rock fracture.Sixty experiments were conducted using rock fractures according to the geometry,aperture sizes,wavelengths,and roughness amplitudes.The overall negative relationship between the normalized electrical resistivity values and the aperture sizes directly linked with the permeability,was well fitted by the power-law function with a large determination coefficient(≈0.86).The effects of wavelength and roughness amplitude of the rock fracture on the electrical resistivity were also analyzed.Results showed that the electrical resistivity was slightly increased with decreasing wavelength and increasing roughness amplitude.An empirical model for evaluating the permeability of a rock fracture was proposed based on the experimental data.In the field,if the electrical resistivity of pore groundwater could be measured in advance,this empirical model could be applied effectively for simple,quick monitoring of the fracture permeability.Although uncertainty may be associated with the permeability estimation due to the limited control parameters considered in this research,this electrical resistivity approach could be helpful to monitor the rock permeability in deep underground facilities such as those used for radioactive waste repositories or forms of energy storage.展开更多
Background Insulin resistance(IR)is significantly associated with coronary artery disease and cardiovascular events in patients with or without type 2 diabetes mellitus.This study aimed to evaluate the influence of ...Background Insulin resistance(IR)is significantly associated with coronary artery disease and cardiovascular events in patients with or without type 2 diabetes mellitus.This study aimed to evaluate the influence of IR on long-term outcomes of patients undergoing percutaneous coronary intervention(PCI)with sirolimus-eluting stent(SES)implantation.Methods A total of 467 consecutive patients undergoing SES-based PCI were divided into lR group(n=104)and non-IR group(n=363).The patients were followed up for one year.The rate of major adverse cardiac events(MACEs) including death, non-fatal myocardial infarction and recurrent angina pectoris was compared by the log-rank test,and the independent risk factors were identified by the Cox regression analysis.Results MACEs occurred more frequently,and cumulative survival rate was lower in the IR group than in the non-IR group during the follow-up (all P〈0.05).IR was an independent risk factor for the occurrence of cardiac death and non-fatal myocardial infarction(OR=2176,95% CI=1.35-5.47,P=0.034).Old age,diabetes,and multi-vessel disease were determinants for recurrent angina pectoris after PCI(P〈0.05).Subgroup analysis revealed that IR(OR=3.35,95% CI=1.07-13.59,P=0.013)and multi-vessel disease(OR=2.19,95%CI=1.01-5.14,P=0.044)were independent risk predictors for recurrent angina pectoris in patients with diabetes after PCI.Conclusions IR is associated with reduced MACE-free survival and remains an independent predictor for recurrent angina pectoris after PCI with SES implantation.展开更多
Although laser ablation is considered as a facile technique to fabricate bio-inspired super-hydrophobic surfaces,the issue is that the initial laser treated metallic surfaces show super-hydrophilic property.It will ta...Although laser ablation is considered as a facile technique to fabricate bio-inspired super-hydrophobic surfaces,the issue is that the initial laser treated metallic surfaces show super-hydrophilic property.It will take a long period to reach super-hydrophobic state under ambient air.It is reported that these super-hydrophobic surfaces could be easily damaged by thermal heating effect or interaction with other liquids,causing uncontrolled loss of super-hydrophobicity.In this study,a stable super-hydrophobic aluminum surface was rapidly fab-ricated via the hybrid laser ablation and surface chemical modification of(heptadecafluoro-1,1,2,2-tetradecyl)triethoxysilane(AC-FAS).Surface morphology and chemistry were systematically investigated to explore the generation mechanism of super-hydrophobicity.The water contact angle of the treated surfaces can reach up to 160.6°±1.5°with rolling angle of 3.0°±1.0°,exhibiting perfect self-cleaning capability,long-term stability,and excellent chemical stability in acidic as well as alkaline solutions.The potentiodynamic polarization tests implied that the super-hydrophobic surfaces showed better anti-corrosion performance.This hybrid laser ablation and surface chemical modification are very time-saving and low-cost,which offers a rapid way for quantity production of super-hydrophobic surface on aluminum material.展开更多
The grain-size dependence of wear resistance of WC-Co cemented carbides(with mean WC grain sizes of 2.2μm,1.6μm,0.8μm and 0.4μm,respectively)was investigated under different tribological conditions.The results sho...The grain-size dependence of wear resistance of WC-Co cemented carbides(with mean WC grain sizes of 2.2μm,1.6μm,0.8μm and 0.4μm,respectively)was investigated under different tribological conditions.The results showed that the grain size had opposite effects on wear resistance of the cemented carbides in dry sliding wear and microabrasion tests.In the former condition,with decrease of WC grain size hence the increase of hardness,plastic deformation,fracture,fragmentation and oxidation were all mitigated,leading to a drastic decrease in the wear rate.In the latter condition,pull-out of WC grains after Co removal dominated the wear,so that the hardness of cemented carbide was not a core factor.As a result,the wear resistance of the cemented carbide generally showed a decreasing trend with decrease of the grain size,except for a slight increase in the ultrafine-grained cemented carbide.Single-pass scratching of the cemented carbides under various loads indicated the same failure mechanism as that in the sliding wear tests.Furthermore,the reasons for severe surface oxidation of the coarse-grained cemented carbides were disclosed.展开更多
The paper presented first results elaborated during the European Research Project Re-road which aims at the development of techniques for increasing the recycling rates of reclaimed asphalt. During service life surfac...The paper presented first results elaborated during the European Research Project Re-road which aims at the development of techniques for increasing the recycling rates of reclaimed asphalt. During service life surface asphalt courses are subjected to aging due to oxidation effects which causes the hardening of the binder and thereby a change in the chemical, physical and mechanical properties of the material. Surface courses often contain highly modified binders as well as special additives for improving the performance characteristics. As these layers inhibit the shortest service lives compared to other road construction layers every year high amounts of reclaimed surface asphalt are available for recycling. The question is raised how the reclaimed asphalt consisting of high quality and costly material components can be recycled for optimal added value. To analyze the asphalt mix service life performance and its recyclability during mix design a laboratory method was developed to simulate the real in-situ aging. First the effects of site aging on the binder and asphalt characteristics were presented. Three laboratory aging methods were discussed which aimed the accelerated aging which meets similar property changes as site aging. At last the effects of two different laboratory aging methods on the same SMA mixture were compared.展开更多
A series of novel dense mixed conducting ceramic membranes based on K2NiF4-type(La1-xCax)2(Ni0.75Cu0.25)O4+δwas successfully prepared through a sol-gel route.Their chemical compatibility,oxygen permeability,CO and CO...A series of novel dense mixed conducting ceramic membranes based on K2NiF4-type(La1-xCax)2(Ni0.75Cu0.25)O4+δwas successfully prepared through a sol-gel route.Their chemical compatibility,oxygen permeability,CO and CO2 tolerance,and long-term CO2 resistance regarding phase composition and crystal structure at different atmospheres were studied.The results show that higher Ca contents in the material lead to the formation of CaCO3.A constant oxygen permeation flux of about 0.63 mL·min−1·cm−2 at 1173 K through a 0.65 mm thick membrane was measured for(La0.9Ca0.1)2(Ni0.75Cu0.25)O4+δ,using either helium or pure CO2 as sweep gas.Steady oxygen fluxes with no sign of deterioration of this membrane were observed with increasing CO2 concentration.The membrane showed excellent chemical stability towards CO2 for more than 1360 h and phase stability in presence of CO for 4 h at high temperature.In addition,this membrane did not deteriorate in a high-energy CO2 plasma.The present work demonstrates that this(La0.9Ca0.1)2(Ni0.75Cu0.25)O4+δmembrane is a promising chemically robust candidate for oxygen separation applications.展开更多
Environmentally-friendly magnetic metallic absorbers with high-performing antioxidant property,thermal stability,and anticorrosion capability have attracted great attention in real-world applications.A surface modific...Environmentally-friendly magnetic metallic absorbers with high-performing antioxidant property,thermal stability,and anticorrosion capability have attracted great attention in real-world applications.A surface modification technology of magnetic metallic absorbers with dense and inert materials has been an effective strategy to solve the aforesaid problem.Herein,fluorinefree core–shell carbonyl iron-organic silicon absorbers(CI@SiO_(2)/1,1,1,3,3,3-hexamethyl disilazane(HMDS))were fabricated via a facile one-pot synthesis using tetraethyl orthosilicate(TEOS)and HMDS as the precursor of protective layer(SiO_(2)/HMDS),and CI@SiO_(2)/HMDS hybrid reveals its long-term corrosion resistance and excellent microwave absorption performance with a minimum reflection loss value of−44.3 dB and an effective absorption bandwidth of 5.3 GHz at a thin thickness of 2.0 mm after immersion in 5.0 wt.%NaCl acidic solutions for 2,160 h.Meanwhile,CI@SiO_(2)/HMDS hybrid can still achieve the maximum radar cross-sectional(RCS)reduction values about 16.5 dB·m^(2) at the detectionθof 0°.The exceptional microwave absorption performance and structural stability are largely due to the extraordinary wave-transparent property and shielding ability against corrosive medium of SiO_(2)/HMDS hydrophobic protective layer with a contact angle of 132.5°.The research paves the way for the large-scale and batch production of high-performance magnetic metallic absorbers and increases their survivability and reliability in the harsh environments.展开更多
文摘Objective:To assess the effectiveness and adverse drug reactions of all-oral regimens for patients with multidrug-resistant tuberculosis.Methods:This retrospective study was conducted at 10 Programmatic Management of Drug Resistant Tuberculosis sites in Punjab province of Pakistan.Patients receiving treatment for drug resistant tuberculosis from July 2019 to December 2020 with at least interim result i.e.6th month culture conversion or final outcomes(cured,complete,lost to follow-up,failure,death)available,were included in the study.Data was extracted from electronic data management system.For the reporting and management of adverse drug events,active tuberculosis drug safety monitoring and management was implemented across all sites.All the data was analyzed using SPSS version 22.Results:Out of 947 drug resistant tuberculosis patients included in this study,579(68%)of the patients had final outcomes available.Of these,384(67.9%)successfully completed their treatment.Out of 368(32%)patients who had their interim results available,all had their 6th month culture negative.Combining new medications was thought to result in serious adverse outcomes such as QT prolongation.However,this study did not record any severe adverse events among patients.Conclusions:All-oral regimens formulation guided by overall treatment effectiveness resulted in treatment outcomes comparable to those obtained with traditional injectable treatment.
基金Natural Science Fund Project of Shaanxi Provincial Education Department(No.12JK0707)regular project of Shaanxi Provincial Sports Bureau(No.2019029).
文摘Objective:To explore the clinical effect of long-term aerobic exercise combined with resistance training in patients with myocardial ischemia caused by coronary heart disease and its influence on cardiac function, exercise endurance and quality of life. Methods:100 patients with myocardial ischemia caused by coronary heart disease from January 2017 to January 2019 were randomly divided into control group (n = 50 cases) and observation group (n = 50 cases). The control group was given resistance training, while the observation group was combined with long-term aerobic exercise on the basis of the control group. The two groups were treated for 3 months. The cardiac function, exercise endurance and quality of life were compared between the two groups. Results:The levels of IVST (8.20+1.32) mm, LVDD (46.43+4.13) mm and LVSD (32.59+3.15) mm in the observation group were lower than those in the control group at 3 months after treatment. The level of LVEF (67.49+5.77)% in the observation group was higher than that in the control group at 3 months after treatment. The difference between the two groups was significant (P<0.05). The ET (55.42+2.9) in the observation group was higher than that in the control group (P<0.05). 2) The levels of ng/L and TXB2 (93.23 + 6.26) ng/L were significantly lower than those of the control group, and the difference between the two groups was statistically significant (P<0.05). The 6-minute walking distance (561.25 +43.64) m and the quality of life score (95.31 +6.39) in the observation group were higher than those in the control group 3 months after treatment, and the difference between the two groups was statistically significant (P<0.05). Conclusions:Long-term aerobic exercise combined with resistance training can improve cardiac function, exercise tolerance and quality of life in patients with myocardial ischemia caused by coronary heart disease, which is worthy of popularization and application.
基金financially supported by the National Key Research and Development Program of China(Grant Nos.2020YFB0311000 and 2017YFB0305201)the Fund of Key Laboratory of Advanced Materials of Ministry of Education(ADV22-12)the Jiangsu Funding Program for Excellent Postdoctoral Talent.
文摘The service performance of heat resistance steels is largely determined by the precipitation kinetics.The nucleation-growth-coarsening behaviors of precipitates in G115 martensitic heat resistance steel during long-term aging at 650℃ have been systemically investigated.The microstructural characteristics,precipitate morphology and alloying element distribution were studied by scanning electron microscopy,transmission electron microscopy and scanning transmission electron microscopy.The lognormal distribution fitting combined with the multiple regression analysis was adopted to evaluate the precipitate size distributions.Laves phase has longer incubation time,and its coarsening rate is almost one order of magnitude higher in comparison with that of M_(23)C_(6) carbide.Furthermore,the nucleation rate,number density,average radius,and volume fraction of two precipitates are simulated based on the classical nucleation theory and the modified Langer-Schwartz model.The precipitation behavior of Laves phase can be well explained with the Fe-W system as the interfacial energy takes 0.10 J/m^(2).In contrast,the simulation results of M_(23)C_(6) carbide in the Fe-Cr-C system are significantly overestimated,which results from the inhibitory effect of boron on coarsening.
文摘The pull-out capacities for soil nailing systems comprising of one single 29 mm diameter(type A) and four 16 mm diameter(type B) rebars with grouted cement were examined.A field test and numerical analysis for the type A and type B systems were carried out to investigate the pull-out capacities and the slope stability reinforcement efficiency in soil and rock slopes.The results of the pull-out tests show the mobilized shear force and load transfer characteristics with respect to soil depth.The load-displacement relationship was examined for both type A and type B systems.Slope stability analyses were carried out to study the relationships between soil and nail reinforcement and bending stiffness as well as combined axial tension and shear forces.Factors of safety were calculated in relation to the number of nails and their outside diameters.Both soil and rock slopes were included in this evaluation.
基金supported by the National Research Foundation of Korea(KRF)grant funded by the Korea government(MSIT)(No.NRF-2019R1G1A1100517)the Basic Research and Development Project of the Korea Institute of Geoscience and Mineral Resources(KIGAM),which was funded by the Ministry of Science and ICT,Korea。
文摘A convenient approach was proposed by which to evaluate and monitor the permeability of a rock fracture by verifying the quantitative correlation between the electrical resistivity and permeability at laboratory scale.For this purpose,an electrical resistivity measurement system was applied to the laboratory experiments using artificial cells with the shape of a single rock fracture.Sixty experiments were conducted using rock fractures according to the geometry,aperture sizes,wavelengths,and roughness amplitudes.The overall negative relationship between the normalized electrical resistivity values and the aperture sizes directly linked with the permeability,was well fitted by the power-law function with a large determination coefficient(≈0.86).The effects of wavelength and roughness amplitude of the rock fracture on the electrical resistivity were also analyzed.Results showed that the electrical resistivity was slightly increased with decreasing wavelength and increasing roughness amplitude.An empirical model for evaluating the permeability of a rock fracture was proposed based on the experimental data.In the field,if the electrical resistivity of pore groundwater could be measured in advance,this empirical model could be applied effectively for simple,quick monitoring of the fracture permeability.Although uncertainty may be associated with the permeability estimation due to the limited control parameters considered in this research,this electrical resistivity approach could be helpful to monitor the rock permeability in deep underground facilities such as those used for radioactive waste repositories or forms of energy storage.
文摘Background Insulin resistance(IR)is significantly associated with coronary artery disease and cardiovascular events in patients with or without type 2 diabetes mellitus.This study aimed to evaluate the influence of IR on long-term outcomes of patients undergoing percutaneous coronary intervention(PCI)with sirolimus-eluting stent(SES)implantation.Methods A total of 467 consecutive patients undergoing SES-based PCI were divided into lR group(n=104)and non-IR group(n=363).The patients were followed up for one year.The rate of major adverse cardiac events(MACEs) including death, non-fatal myocardial infarction and recurrent angina pectoris was compared by the log-rank test,and the independent risk factors were identified by the Cox regression analysis.Results MACEs occurred more frequently,and cumulative survival rate was lower in the IR group than in the non-IR group during the follow-up (all P〈0.05).IR was an independent risk factor for the occurrence of cardiac death and non-fatal myocardial infarction(OR=2176,95% CI=1.35-5.47,P=0.034).Old age,diabetes,and multi-vessel disease were determinants for recurrent angina pectoris after PCI(P〈0.05).Subgroup analysis revealed that IR(OR=3.35,95% CI=1.07-13.59,P=0.013)and multi-vessel disease(OR=2.19,95%CI=1.01-5.14,P=0.044)were independent risk predictors for recurrent angina pectoris in patients with diabetes after PCI.Conclusions IR is associated with reduced MACE-free survival and remains an independent predictor for recurrent angina pectoris after PCI with SES implantation.
基金Program of International S&T Cooperation(No.2016YFE0112100)National Key R&D Program of China(No.2017YFBl104700)+1 种基金H2020 Project(FabSurfWAR-644971)National Natural Science Foundations of China(Nos.51675371,51675376 and 51675367).
文摘Although laser ablation is considered as a facile technique to fabricate bio-inspired super-hydrophobic surfaces,the issue is that the initial laser treated metallic surfaces show super-hydrophilic property.It will take a long period to reach super-hydrophobic state under ambient air.It is reported that these super-hydrophobic surfaces could be easily damaged by thermal heating effect or interaction with other liquids,causing uncontrolled loss of super-hydrophobicity.In this study,a stable super-hydrophobic aluminum surface was rapidly fab-ricated via the hybrid laser ablation and surface chemical modification of(heptadecafluoro-1,1,2,2-tetradecyl)triethoxysilane(AC-FAS).Surface morphology and chemistry were systematically investigated to explore the generation mechanism of super-hydrophobicity.The water contact angle of the treated surfaces can reach up to 160.6°±1.5°with rolling angle of 3.0°±1.0°,exhibiting perfect self-cleaning capability,long-term stability,and excellent chemical stability in acidic as well as alkaline solutions.The potentiodynamic polarization tests implied that the super-hydrophobic surfaces showed better anti-corrosion performance.This hybrid laser ablation and surface chemical modification are very time-saving and low-cost,which offers a rapid way for quantity production of super-hydrophobic surface on aluminum material.
基金supported financially by the National Natural Science Foundation of China (Nos.51601004,51631002,51425101 and 51621003)the China Scholarship Council (201806545002)the Program of Top Disciplines Construction in Beijing (No. PXM2019_014204_500031)
文摘The grain-size dependence of wear resistance of WC-Co cemented carbides(with mean WC grain sizes of 2.2μm,1.6μm,0.8μm and 0.4μm,respectively)was investigated under different tribological conditions.The results showed that the grain size had opposite effects on wear resistance of the cemented carbides in dry sliding wear and microabrasion tests.In the former condition,with decrease of WC grain size hence the increase of hardness,plastic deformation,fracture,fragmentation and oxidation were all mitigated,leading to a drastic decrease in the wear rate.In the latter condition,pull-out of WC grains after Co removal dominated the wear,so that the hardness of cemented carbide was not a core factor.As a result,the wear resistance of the cemented carbide generally showed a decreasing trend with decrease of the grain size,except for a slight increase in the ultrafine-grained cemented carbide.Single-pass scratching of the cemented carbides under various loads indicated the same failure mechanism as that in the sliding wear tests.Furthermore,the reasons for severe surface oxidation of the coarse-grained cemented carbides were disclosed.
基金Funed by the Europeans Community’s Seventh Framework Program(FP7/2007-2013) (No. SCP-GA-2008-218747)
文摘The paper presented first results elaborated during the European Research Project Re-road which aims at the development of techniques for increasing the recycling rates of reclaimed asphalt. During service life surface asphalt courses are subjected to aging due to oxidation effects which causes the hardening of the binder and thereby a change in the chemical, physical and mechanical properties of the material. Surface courses often contain highly modified binders as well as special additives for improving the performance characteristics. As these layers inhibit the shortest service lives compared to other road construction layers every year high amounts of reclaimed surface asphalt are available for recycling. The question is raised how the reclaimed asphalt consisting of high quality and costly material components can be recycled for optimal added value. To analyze the asphalt mix service life performance and its recyclability during mix design a laboratory method was developed to simulate the real in-situ aging. First the effects of site aging on the binder and asphalt characteristics were presented. Three laboratory aging methods were discussed which aimed the accelerated aging which meets similar property changes as site aging. At last the effects of two different laboratory aging methods on the same SMA mixture were compared.
基金This work is part of the project “Plasma-induced CO2-conversion”(PiCK,project number:03SFK2S3B)and financially supported by the German Federal Ministry of Education and Research in the framework of the“Kopemikus projects for the Energiewende”.The authors are thankfUl to B.Sc.Laura Steinle(University of Stuttgart)for her assistance during the CO stability tests,and Christine Stefani and Prof.Dr.Robert Dinnebier(Max Planck Institute for Solid State Research,Stuttgart)for the in situ PXRD measurements,respectively.G.C.thanks Frank Hack and Dr.Angelika Veziridis for their kind support during experiments and discussions.
文摘A series of novel dense mixed conducting ceramic membranes based on K2NiF4-type(La1-xCax)2(Ni0.75Cu0.25)O4+δwas successfully prepared through a sol-gel route.Their chemical compatibility,oxygen permeability,CO and CO2 tolerance,and long-term CO2 resistance regarding phase composition and crystal structure at different atmospheres were studied.The results show that higher Ca contents in the material lead to the formation of CaCO3.A constant oxygen permeation flux of about 0.63 mL·min−1·cm−2 at 1173 K through a 0.65 mm thick membrane was measured for(La0.9Ca0.1)2(Ni0.75Cu0.25)O4+δ,using either helium or pure CO2 as sweep gas.Steady oxygen fluxes with no sign of deterioration of this membrane were observed with increasing CO2 concentration.The membrane showed excellent chemical stability towards CO2 for more than 1360 h and phase stability in presence of CO for 4 h at high temperature.In addition,this membrane did not deteriorate in a high-energy CO2 plasma.The present work demonstrates that this(La0.9Ca0.1)2(Ni0.75Cu0.25)O4+δmembrane is a promising chemically robust candidate for oxygen separation applications.
基金supported by the National Natural Science Foundation of China(Nos.51972045 and 5197021414)the Fundamental Research Funds for the Chinese Central Universities,China(No.ZYGX2019J025)+2 种基金Sichuan Science and Technology Program(Nos.2020JDRC0015 and 2020JDRC0045)the Natural Science Foundation of Sichuan(No.2022NSFSC0347)Sichuan Science and Technology Innovation Talent Project(No.2021JDRC0021).
文摘Environmentally-friendly magnetic metallic absorbers with high-performing antioxidant property,thermal stability,and anticorrosion capability have attracted great attention in real-world applications.A surface modification technology of magnetic metallic absorbers with dense and inert materials has been an effective strategy to solve the aforesaid problem.Herein,fluorinefree core–shell carbonyl iron-organic silicon absorbers(CI@SiO_(2)/1,1,1,3,3,3-hexamethyl disilazane(HMDS))were fabricated via a facile one-pot synthesis using tetraethyl orthosilicate(TEOS)and HMDS as the precursor of protective layer(SiO_(2)/HMDS),and CI@SiO_(2)/HMDS hybrid reveals its long-term corrosion resistance and excellent microwave absorption performance with a minimum reflection loss value of−44.3 dB and an effective absorption bandwidth of 5.3 GHz at a thin thickness of 2.0 mm after immersion in 5.0 wt.%NaCl acidic solutions for 2,160 h.Meanwhile,CI@SiO_(2)/HMDS hybrid can still achieve the maximum radar cross-sectional(RCS)reduction values about 16.5 dB·m^(2) at the detectionθof 0°.The exceptional microwave absorption performance and structural stability are largely due to the extraordinary wave-transparent property and shielding ability against corrosive medium of SiO_(2)/HMDS hydrophobic protective layer with a contact angle of 132.5°.The research paves the way for the large-scale and batch production of high-performance magnetic metallic absorbers and increases their survivability and reliability in the harsh environments.