To further reveal the failure mechanisms of thick ultra-high molecular weight polyethylene(UHMWPE)laminates,field firing tests were conducted for 10-,20-,and 30-mm thick laminates against 12.7-mm calibre wedge-shaped ...To further reveal the failure mechanisms of thick ultra-high molecular weight polyethylene(UHMWPE)laminates,field firing tests were conducted for 10-,20-,and 30-mm thick laminates against 12.7-mm calibre wedge-shaped fragment simulated projectiles at high velocities between 450 and 1200 m/s.The ballistic performance,deformation process,and staged failure characteristics of the laminates with different thicknesses were compared and analysed.The results demonstrate that the ballistic limits of the UHMWPE laminates increase almost linearly with laminate thickness.The 10-mm thick laminate generally experiences two-stage failure characteristics,whereas three-staged failure occurs in the 20-and 30-mm thick laminates and the progressive delamination is evident.The energy limit concept representing the maximum energy absorption efficiency and the idea of reuse of the thick UHMWPE laminates are proposed in this study.The findings of this research will be useful in the design of flexible and effective UHMWPE-based protective equipment.展开更多
Fast reactors based on thorium fuel have enhanced inherent safety. Fluoride salt performs well as a coolant in high-temperature nuclear systems. In this paper,we present a reference core for a large fluoride-salt-cool...Fast reactors based on thorium fuel have enhanced inherent safety. Fluoride salt performs well as a coolant in high-temperature nuclear systems. In this paper,we present a reference core for a large fluoride-salt-cooled solid-fuel fast reactor(LSFR) using thorium–uranium fuel cycle. Neutronics physics of the LSFR reference core is investigated with 2D and 3D in-core fuel management strategy. The design parameters analyzed include the fuel volume fraction, power density level and continuous removal of fission products with 3D fuel shuffling that obtains better equilibrium core performance than 2D shuffling. A self-sustained core is achieved for all cases,and the core of 60% fuel volume fraction at 50 MW/m^3 power density is of the best breeding performance(average breeding ratio 1.134). The LSFR core based on thorium fuel is advantageous in its high discharge burn-up of 20–30% fissions per initial heavy metal atom, small reactivity swing over the whole lifetime(to simplify the reactivity control system), the negative reactivity temperature coefficient(intrinsically safe for all cases) and accepted cladding peak radiation damage. The LSFR reactor is a good alternative option for the deployment of a self-sustained thorium-based nuclear system.展开更多
Objective:To find out the clinical randomized controlled trials of Tuina in the treatment of insomnia,and to incorporate it into the research results of this subject for meta-analysis.While comparing the clinical effe...Objective:To find out the clinical randomized controlled trials of Tuina in the treatment of insomnia,and to incorporate it into the research results of this subject for meta-analysis.While comparing the clinical effects,we can compare the literature and research related to Tuina treatment of insomnia and other treatments of insomnia,and summarize its characteristics and advantages.Methods:Relevant searches were performed on CNKI,VIP,CBMdisc,WanFang,Embase,Cochrance,PubMed,etc.Find out the effects of related massage therapy on the treatment of insomnia.Clinical Randomized Controlled Medical Research Clinical Trials(RCT).According to the inclusion criteria and exclusion criteria,the literature was screened,and then the included literature was extracted as data after screening.RevMan5.3 software was used to integrate and analyze the data.Results:19 randomized controlled trials that met the criteria were classified as studies,with a total of 1625 patients.The results of Meta-analysis showed that the total effective rate of massage for insomnia(OR=4.20,95%CI:3.00-5.88,P<0.00001),suggesting that the clinical efficacy of Tuina for insomnia is better than traditional Chinese medicine,western medicine,ear point treatment and acupuncture treatment.The difference in experimental effects was statistically significant,and no adverse reactions were found.Conclusion:The use of Tuina methods combined with different types of massage treatments to treat insomnia has a good therapeutic effect and no serious adverse events occurred.However,due to the limitations of this study,more large-sample,multi-center,in-depth clinical studies are needed to provide more reliable evidence-based evidence for the clinic,in order to better serve the development of guidelines.展开更多
A new class of axially chiral aryl-alkene-indole frameworks have been designed,and the first catalytic asymmetric construction of such scaffolds has been established by the strategy of organocatalytic(Z/E)-selective a...A new class of axially chiral aryl-alkene-indole frameworks have been designed,and the first catalytic asymmetric construction of such scaffolds has been established by the strategy of organocatalytic(Z/E)-selective and enantioselective(4+3)cyclization of 3-alkynyl-2-indolylmethanols with 2-naphthols or phenols(all>95:5 E/Z,up to 98% yield,97% ee).This reaction also represents the first catalytic asymmetric construction of axially chiral alkene-heteroaryl scaffolds,which will add a new member to the atropisomeric family.This approach has not only confronted the great challenges in constructing axially chiral alkene-heteroaryl scaffolds but also provided a powerful strategy for the enantioselective construction of axially chiral aryl-alkene-indole frameworks.展开更多
Recently discovered reflective Pancharatnam-Berry phase(PB phase)from chiral anisotropic media(e.g.,cholesteric liquid crystal,CLC)has aroused great interest in the emerging frontier of planar optics.However,the singl...Recently discovered reflective Pancharatnam-Berry phase(PB phase)from chiral anisotropic media(e.g.,cholesteric liquid crystal,CLC)has aroused great interest in the emerging frontier of planar optics.However,the single chirality of common CLCs results in the intrinsic limitation of the same spin-selective PB phase manipulation,which means the reversal of the input spin cannot realize the conjugated PB phase.In this work,an innovative scheme based on opposite-chirality-coexisted superstructures is proposed to simultaneously modulate orthogonal circular polarization and get PB phase reversal.Through refilling CLC into a washed-out polymer network with opposite chirality and delicate photo-patterned structures,reflective optical vortex(OV)with opposite topological charges and vector beams with conjugated spiral PB phases are efficiently generated depending on the incident polarization.Furthermore,OV holograms are encoded to reconstruct polarization-selective OV arrays,indicating the strong capability of such opposite-chirality-coexisted anisotropic media.This work provides a new compact platform for planar optics,and sheds light on the architectures and functionalities of chiral superstructures.展开更多
of main observation and conclusion A new class of indole-based allylic donors have been designed and developed for palladium-catalyzed decarboxylative allylations.In addition,the first application of these indole-base...of main observation and conclusion A new class of indole-based allylic donors have been designed and developed for palladium-catalyzed decarboxylative allylations.In addition,the first application of these indole-based allylic donors in palladium-catalyzed decarboxylative[3+2]cydoaddition and allylic amination has been achieved by reacting with isocyanates and sulfonyl amines,respectively.This approach represents the first design of indole-based allylic donors,which is helpful for settling the challenge of designing and developing new class of heterocycle-based allylic donors for Pd-catalyzed decarboxylative allylation reactions.Moreover,the application of this new class of allylic donors in cycloadditions and substitutions will add new contents to the research field of decarboxylative allylation.展开更多
Purpose The increasing number of deaths due to road traffic accidents(RTAs)has attracted global attention.However,the influence of road types is rarely considered in the study of RTAs.This study evaluates the influenc...Purpose The increasing number of deaths due to road traffic accidents(RTAs)has attracted global attention.However,the influence of road types is rarely considered in the study of RTAs.This study evaluates the influence of different road types in RTAs in northern Guizhou to provide a basis for the formulation of evidence-based policies and measures.Methods We obtained the data from the Zunyi Traffic Management Data Platform for the years 2009–2018.The mortality rates of RTAs were calculated.Descriptive methods and Chi-square tests were used to analyze the characteristics of road traffic collisions on different road types.We also examined the associations between the mortality rate per 10,000 vehicles and the growth of per capital gross domestic product(GDP)with Spearman’s rank correlation analysis.According to the passing volume and the infrastructure,we defined different types of roads,like administrative road,functional road,general urban road and urban expressway.Results In 2012,the traffic mortality rate of administrative roads was 8.9 per 100,000 people,and the mortality rate of functional roads was 7.4 per 100,000 people,which decreased in 2018 to 6.1 deaths per 100,000 people and 5.2 deaths per 100,000 people,respectively.The mortality rate per 10,000 vehicles reached the highest level in 2011(28.8 per 10,000 vehicles and 22.5 per 10,000 vehicles on administrative and functional roads,respectively).The death rate of county roads was the highest among administrative roads(χ^(2)=17.389,p<0.05)and that of fourth-class roads was the highest among functional roads(χ^(2)=21.785,p<0.05).The mortality rate per 10,000 vehicles was negatively correlated with per capital GDP.Conclusion Although our research shows that RTAs in northern Guizhou have steadily declined in recent years,the range of decline is relatively small.Many measures and sustainable efforts are needed to control road traffic death and accelerate the progress in road traffic safety in northern Guizhou.展开更多
基金the financial support from National Natural Science Foundation of China(Grant No.51978166)National Key Research and Development Program of China(Grant No.2019YFC0706105,2021YFC3100703)the Fundamental Research Funds for the Central Universities(Grant No.2242022R10124s)。
文摘To further reveal the failure mechanisms of thick ultra-high molecular weight polyethylene(UHMWPE)laminates,field firing tests were conducted for 10-,20-,and 30-mm thick laminates against 12.7-mm calibre wedge-shaped fragment simulated projectiles at high velocities between 450 and 1200 m/s.The ballistic performance,deformation process,and staged failure characteristics of the laminates with different thicknesses were compared and analysed.The results demonstrate that the ballistic limits of the UHMWPE laminates increase almost linearly with laminate thickness.The 10-mm thick laminate generally experiences two-stage failure characteristics,whereas three-staged failure occurs in the 20-and 30-mm thick laminates and the progressive delamination is evident.The energy limit concept representing the maximum energy absorption efficiency and the idea of reuse of the thick UHMWPE laminates are proposed in this study.The findings of this research will be useful in the design of flexible and effective UHMWPE-based protective equipment.
基金supported by the ‘‘Strategic Priority Research Program’’ of the Chinese Academy of Sciences(No.XDA02010200)the Frontier Science Key Program of Chinese Academy of Sciences(No.QYZDY-SSW-JSC016)
文摘Fast reactors based on thorium fuel have enhanced inherent safety. Fluoride salt performs well as a coolant in high-temperature nuclear systems. In this paper,we present a reference core for a large fluoride-salt-cooled solid-fuel fast reactor(LSFR) using thorium–uranium fuel cycle. Neutronics physics of the LSFR reference core is investigated with 2D and 3D in-core fuel management strategy. The design parameters analyzed include the fuel volume fraction, power density level and continuous removal of fission products with 3D fuel shuffling that obtains better equilibrium core performance than 2D shuffling. A self-sustained core is achieved for all cases,and the core of 60% fuel volume fraction at 50 MW/m^3 power density is of the best breeding performance(average breeding ratio 1.134). The LSFR core based on thorium fuel is advantageous in its high discharge burn-up of 20–30% fissions per initial heavy metal atom, small reactivity swing over the whole lifetime(to simplify the reactivity control system), the negative reactivity temperature coefficient(intrinsically safe for all cases) and accepted cladding peak radiation damage. The LSFR reactor is a good alternative option for the deployment of a self-sustained thorium-based nuclear system.
基金This research is supported by National Demonstration Center for Experimental Education,Acupuncture Demonstration Center Innovation Project,Funded Project Number:201101.Instructor:Xiang-Wen Meng.
文摘Objective:To find out the clinical randomized controlled trials of Tuina in the treatment of insomnia,and to incorporate it into the research results of this subject for meta-analysis.While comparing the clinical effects,we can compare the literature and research related to Tuina treatment of insomnia and other treatments of insomnia,and summarize its characteristics and advantages.Methods:Relevant searches were performed on CNKI,VIP,CBMdisc,WanFang,Embase,Cochrance,PubMed,etc.Find out the effects of related massage therapy on the treatment of insomnia.Clinical Randomized Controlled Medical Research Clinical Trials(RCT).According to the inclusion criteria and exclusion criteria,the literature was screened,and then the included literature was extracted as data after screening.RevMan5.3 software was used to integrate and analyze the data.Results:19 randomized controlled trials that met the criteria were classified as studies,with a total of 1625 patients.The results of Meta-analysis showed that the total effective rate of massage for insomnia(OR=4.20,95%CI:3.00-5.88,P<0.00001),suggesting that the clinical efficacy of Tuina for insomnia is better than traditional Chinese medicine,western medicine,ear point treatment and acupuncture treatment.The difference in experimental effects was statistically significant,and no adverse reactions were found.Conclusion:The use of Tuina methods combined with different types of massage treatments to treat insomnia has a good therapeutic effect and no serious adverse events occurred.However,due to the limitations of this study,more large-sample,multi-center,in-depth clinical studies are needed to provide more reliable evidence-based evidence for the clinic,in order to better serve the development of guidelines.
基金financial support from NSFC(Nos.21772069 and 21831007)Six Kinds of Talents Project of Jiangsu Province(No.SWYY-025).
文摘A new class of axially chiral aryl-alkene-indole frameworks have been designed,and the first catalytic asymmetric construction of such scaffolds has been established by the strategy of organocatalytic(Z/E)-selective and enantioselective(4+3)cyclization of 3-alkynyl-2-indolylmethanols with 2-naphthols or phenols(all>95:5 E/Z,up to 98% yield,97% ee).This reaction also represents the first catalytic asymmetric construction of axially chiral alkene-heteroaryl scaffolds,which will add a new member to the atropisomeric family.This approach has not only confronted the great challenges in constructing axially chiral alkene-heteroaryl scaffolds but also provided a powerful strategy for the enantioselective construction of axially chiral aryl-alkene-indole frameworks.
基金This work was supported by the National Key R&D Program of China(No.2021YFA1202000)the National Natural Science Foundation of China(NSFC)(Nos.62175101,12004175,62035008,and 62105143)+3 种基金the Natural Science Foundation of Jiangsu Province(Nos.BK20212004,and BK20200311)the Innovation Program for Quantum Science and Technology(No.2021ZD0301500)the Fundamental Research Funds for the Central Universities(No.021314380185)the Innovation and Entrepreneurship Program of Jiangsu Province.
文摘Recently discovered reflective Pancharatnam-Berry phase(PB phase)from chiral anisotropic media(e.g.,cholesteric liquid crystal,CLC)has aroused great interest in the emerging frontier of planar optics.However,the single chirality of common CLCs results in the intrinsic limitation of the same spin-selective PB phase manipulation,which means the reversal of the input spin cannot realize the conjugated PB phase.In this work,an innovative scheme based on opposite-chirality-coexisted superstructures is proposed to simultaneously modulate orthogonal circular polarization and get PB phase reversal.Through refilling CLC into a washed-out polymer network with opposite chirality and delicate photo-patterned structures,reflective optical vortex(OV)with opposite topological charges and vector beams with conjugated spiral PB phases are efficiently generated depending on the incident polarization.Furthermore,OV holograms are encoded to reconstruct polarization-selective OV arrays,indicating the strong capability of such opposite-chirality-coexisted anisotropic media.This work provides a new compact platform for planar optics,and sheds light on the architectures and functionalities of chiral superstructures.
基金We are grateful for financial support from NSFC(Nos.21772069,21831007 and 21702077)the Natural Science Founda-tion of Jiangsu Province(No.BK20170227)Six Kinds of Talents Project of Jiangsu Province(No.SWYY-025).
文摘of main observation and conclusion A new class of indole-based allylic donors have been designed and developed for palladium-catalyzed decarboxylative allylations.In addition,the first application of these indole-based allylic donors in palladium-catalyzed decarboxylative[3+2]cydoaddition and allylic amination has been achieved by reacting with isocyanates and sulfonyl amines,respectively.This approach represents the first design of indole-based allylic donors,which is helpful for settling the challenge of designing and developing new class of heterocycle-based allylic donors for Pd-catalyzed decarboxylative allylation reactions.Moreover,the application of this new class of allylic donors in cycloadditions and substitutions will add new contents to the research field of decarboxylative allylation.
基金The study was supported by the National Natural Science Foundation of China(NSFC No.81760233)Science and Technology Project of Guizhou Province(No.[2020]4Y149 and[2019]5661).
文摘Purpose The increasing number of deaths due to road traffic accidents(RTAs)has attracted global attention.However,the influence of road types is rarely considered in the study of RTAs.This study evaluates the influence of different road types in RTAs in northern Guizhou to provide a basis for the formulation of evidence-based policies and measures.Methods We obtained the data from the Zunyi Traffic Management Data Platform for the years 2009–2018.The mortality rates of RTAs were calculated.Descriptive methods and Chi-square tests were used to analyze the characteristics of road traffic collisions on different road types.We also examined the associations between the mortality rate per 10,000 vehicles and the growth of per capital gross domestic product(GDP)with Spearman’s rank correlation analysis.According to the passing volume and the infrastructure,we defined different types of roads,like administrative road,functional road,general urban road and urban expressway.Results In 2012,the traffic mortality rate of administrative roads was 8.9 per 100,000 people,and the mortality rate of functional roads was 7.4 per 100,000 people,which decreased in 2018 to 6.1 deaths per 100,000 people and 5.2 deaths per 100,000 people,respectively.The mortality rate per 10,000 vehicles reached the highest level in 2011(28.8 per 10,000 vehicles and 22.5 per 10,000 vehicles on administrative and functional roads,respectively).The death rate of county roads was the highest among administrative roads(χ^(2)=17.389,p<0.05)and that of fourth-class roads was the highest among functional roads(χ^(2)=21.785,p<0.05).The mortality rate per 10,000 vehicles was negatively correlated with per capital GDP.Conclusion Although our research shows that RTAs in northern Guizhou have steadily declined in recent years,the range of decline is relatively small.Many measures and sustainable efforts are needed to control road traffic death and accelerate the progress in road traffic safety in northern Guizhou.
