The current margins of the North China and Yangtze Cratons provide arguably the best examples globally of anomalously high mineral endowment within a 100 km buffer zone,hosting 66 diverse world-class to giant ore syst...The current margins of the North China and Yangtze Cratons provide arguably the best examples globally of anomalously high mineral endowment within a 100 km buffer zone,hosting 66 diverse world-class to giant ore systems that help explain China’s premier position as a producer of multiple metal and mineral commodities.After the cratonization of these crustal blocks during the Neoarchean-Paleoproterozoic,with incorporation of iron ores on assembled micro-block margins,the margins of the cratons experienced multiple convergence and rifting events leading to metasomatism and fertilization of their underlying sub-continental lithospheric mantle.The rifted margins with trans-lithosphere faults provided pathways for Cu-Au(Mo-W-Sn)-bearing felsic to Ni-Cu-bearing ultrabasic intrusions and REE-rich carbonatite magmas,and for the development of marginal sedimentary basins with both Cu-Pb-Zn-rich source units and reactive carbonate or carbonaceous host rocks.There was diachronous formation of hydrothermal orogenic gold,antimony,and bismuth systems in the narrow orogenic belts between the cratons.Complexity in the Mesozoic Paleo-Pacific subduction systems resulted in asthenosphere upwelling and lithosphere extension and thinning in the North China Craton,leading to anomalous heat flow and formation of orogenic gold deposits,including those of the giant Jiaodong gold province on its north-eastern margin.These gold deposits,many of which formed from fluids liberated by devolatilization of previously metasomatized sub-continental lithospheric mantle,helped propel China to be the premier gold producer globally.The thick sub-continental lithospheric mantle of the cold buoyant cratons helped the preservation of some of the world’s oldest porphyry-skarn and epithermal mineral systems.Although craton margins globally control the formation and preservation of a diverse range of mineral deposits,China represents the premier example in terms of metal endowment due to the anomalous length of its craton margins combined with their abnormally complex tectonic history.展开更多
To reveal the affecting mechanism of cooling rate on lamellarαprecipitation,the precipitation behaviors of lamellarαphase in IMI834 titanium alloy during isothermal and non-isothermal heat treatments were quantitati...To reveal the affecting mechanism of cooling rate on lamellarαprecipitation,the precipitation behaviors of lamellarαphase in IMI834 titanium alloy during isothermal and non-isothermal heat treatments were quantitatively characterized using experimental analysis.Critical precipitation temperatures at various cooling rates were obtained using thermal dilatation testing.Using metallographic microscopy,electron microprobe analysis,and data fitting methods,the quantitative evolution models of average width,volume fraction,and solute concentration in theαandβphases were built for different temperatures or cooling rates.A comparison between the two precipitation behaviors showed that the average width and volume fraction of lamellarαphase under non-isothermal conditions were smaller than those under isothermal conditions.With increasing cooling rate,the average width and volume fraction were decreased significantly,and the critical precipitation temperatures were reduced.This phenomenon is mainly attributed to the decreased diffusion velocity of solutes Al,Mo,and Nb with increasing cooling rate.展开更多
There are large volumes of the Phanerozoic granitoid rocks in China and neighboring areas.In recent years,numerous new and precise U-Pb zircon ages have been published for these granitoids,and define many important ma...There are large volumes of the Phanerozoic granitoid rocks in China and neighboring areas.In recent years,numerous new and precise U-Pb zircon ages have been published for these granitoids,and define many important magmatic events,such as ca.500 Ma granitoid events in the West Junggar,Altai orogens in the NW China,and Qinling orogen in the central China.These ages accurately constrain the time of important early Paleozoic,late Paleozoic,early Mesozoic and late Mesozoic magmatic events of the northern,central,western,southern and eastern orogenic Mountains in China.There occur various types of granitoids in China,such as talc-alkaline granite,alkali granite,highly-fractionated granite,leucogranite, adakite,and rapakivi granite.Rapakivi granites are not only typical Proterozoic as in the North China Craton,but were also emplaced during Paleozoic and Mesozoic in the Kunlun-Qinling orogen,a part of the China Central Orogenic Belt (CCOB).Nd-Hf isotopic tracing and mapping show that granitoids inthe southern Central Asian Orogenic Belt (CAOB)in China (or the Northern China Orogenic Belt)are characterized predominantly by juvenile sources.The juvenile crust in this orogenic domain accounts for over 50% by area,distinguishing it from other orogenic belts in the world,and those in central (e.g.,Qinling),southwestem and eastern China.Based on a large amount of new age data,a preliminary granitoid and granitoid-tectonic maps of China have been preliminarily compiled,and an evolutionary framework of Phanerozoic granitoids in China and neighboring areas has been established from the view of assembly and breakup of continental blocks.Research ideas on granitoid tectonics has also been proposed and discussed.展开更多
1.Objectives The porphyry copper deposits (PCD) are usually hosted in a multistage intrusive complex but only causallyrelated tospecific magma of high oxidation state and water content. The copper enrichment of the po...1.Objectives The porphyry copper deposits (PCD) are usually hosted in a multistage intrusive complex but only causallyrelated tospecific magma of high oxidation state and water content. The copper enrichment of the porphyry system is caused by accumulation during magmatic differentiation (Hou ZQ et al., 2015). Thus, study on magmatic evolution and Cu mineralization process is important for understanding the formation of PCD.展开更多
The electric gating on the transport properties of two-dimensional electron gas(2DEG) at the interface of LaAlO_(3)/SrTiO_(3)(LAO/STO) heterostructure has attracted great research interest due to its potential applica...The electric gating on the transport properties of two-dimensional electron gas(2DEG) at the interface of LaAlO_(3)/SrTiO_(3)(LAO/STO) heterostructure has attracted great research interest due to its potential application in fieldeffect devices. Most of previous works of gate effect were focused on the LAO/STO heterostructure containing only one conductive interface. Here, we systematically investigated the gate effect on high-quality LAO/STO superlattices(SLs)fabricated on the TiO_(2)-terminated(001) STO substrates. In addition to the good metallicity of all SLs, we found that there are two types of charge carriers, the majority carriers and the minority carriers, coexisting in the SLs. The sheet resistance of the SLs with a fixed thickness of the LAO layer increases monotonically as the thickness of the STO layer increases. This is derived from the dependence of the minority carrier density on the thickness of STO. Unlike the LAO/STO heterostructure in which minority and majority carriers are simultaneously modulated by the gate effect, the minority carriers in the SLs can be tuned more significantly by the electric gating while the density of majority carriers is almost invariable. Thus, we consider that the minority carriers may mainly exist in the first interface near the STO substrate that is more sensitive to the back-gate voltage, and the majority carriers exist in the post-deposited STO layers. The SL structure provides the space separation for the multichannel conduction in the 2 DEG, which opens an avenue for the design of field-effect devices based on LAO/STO heterostructure.展开更多
A direct asymmetric tandem reaction of a-nitro ketones with b g-unsaturated a-ketoesters was found to be catalyzed by a bifunctional rosin-derived thiourea and gave 5-nitro-2-actoxyl-2-pentenates in excellent ee value...A direct asymmetric tandem reaction of a-nitro ketones with b g-unsaturated a-ketoesters was found to be catalyzed by a bifunctional rosin-derived thiourea and gave 5-nitro-2-actoxyl-2-pentenates in excellent ee values and yields,a much better result than previously reported.Furthermore,through theoretical analysis,literature research and experimental verifications,a new mechanism involving an inverse-electron-demand Diels–Alder（IEDDAR） and a retro-Henry reaction was proposed.展开更多
Background Dengue is a major global health threat with varied clinical manifestations across age groups,countries,and regions.This study aims to estimate global dengue disability weights(DWs)based on clinical manifest...Background Dengue is a major global health threat with varied clinical manifestations across age groups,countries,and regions.This study aims to estimate global dengue disability weights(DWs)based on clinical manifestations data and examine variations across different demographics and geographical areas.These findings will inform public health strategies and interventions to reduce the global burden of dengue.Methods We conducted a systematic search across six databases(Scopus,Web of Science,PubMed,China National Knowledge Infrastructure,Wanfang Data,and Database of Chinese sci-tech periodicals)for studies on human dengue clinical manifestations or infection from the establishment of each database through December 31,2023.DWs were estimated by combining clinical manifestations frequencies with corresponding DW values derived from the Global Burden of Disease(GBD)study,using Monte Carlo simulations to generate uncertainty intervals.Odds ratios(ORs)with 95%confidence intervals(CI)and Chi-square tests were performed to compare clinical manifestations between adults and children.Results A total of 35 adult studies(7109 cases)and 17 pediatric studies(2996 cases)were analysed.Adults had higher rates of muscle pain(OR=9.18;95%CI:8.17–10.33)and weak(OR=4.95;95%CI 4.12–5.98).Children showed higher frequencies of decreased appetite(OR=0.12;95%CI:0.11–0.14)and lymphadenectasis(OR=0.04;95%CI:0.03–0.06).Severe dengue was more prevalent in children(8.2%)than adults(4.6%).The global DW for universal dengue was 0.3258 in adults and 0.4022 in children,with Indian children showing the highest DW for severe dengue(0.6991)and Chinese adult showing the highest DW for severe dengue(0.7214).Regionally,most studies were from South and Southeast Asia,with India contributing the largest number of publications(80 articles).Additionally,India had the highest dengue disease burden in 2021(352,468.54 person-years).Conclusions These findings reveal important age and regional differences in dengue disease burden.There is a relative lack of research on dengue clinical manifestations in several high-burden countries in the Americas,and these gaps may affect the comprehensiveness and accuracy of global dengue disability weight estimates.These highlight the urgent need for targeted interventions and optimized resource allocation to mitigate its global impact.展开更多
Diarrhea can occur at an early or advanced stage of acquired immunodeficiency syndrome(AIDS)as a usual symptom in people with human immunodeficiency virus(HIV)infection.While it is usually not fatal,it can influence p...Diarrhea can occur at an early or advanced stage of acquired immunodeficiency syndrome(AIDS)as a usual symptom in people with human immunodeficiency virus(HIV)infection.While it is usually not fatal,it can influence patients’quality of life seriously.It has shown to be efficacious and improves people’s immune status to a certain extent to treat HIV/AIDS-related diarrhea on the basis of syndrome differentiation and treatment or Chinese herbs plus conventional treatment.Therefore,it may have a good application potential.Here,we outline a protocol for the systematic review of this health-care intervention,with the aim to evaluate the beneficial effects and safety of Traditional Chinese Medicine(TCM)for patients who suffer from HIV/AIDS-associated diarrhea.Randomized controlled trials that compare Chinese herbs with placebo or other effective treatments will be searched and included,in spite of publication status or language.The primary outcomes include diarrhea frequency and fecal character.The databases we will search as follows:China Science and Technology Journal Database(VIP),Chinese Biomedical Literature Database(Sino Med),Wanfang Data,China National Knowledge Infrastructure,Pub Med and the CENTRAL in Cochrane Library.Two authors will respectively conduct the screening of trials,data extraction,and use the Cochrane risk of bias tool to assess the methodological quality.We will analyze the data and perform a meta-analysis if possible.We intend to identify potential therapeutic modalities that may be of benefit to inform clinical practice by supplying existing evidence of the helpful effects and safety of TCM to treat patients suffering from HIV/AIDS-associated diarrhea.展开更多
A ballastless slab track,which is commonly used in the track structures of heavy-haul railway tunnels,was analysed based on field measurement data of the Fuyingzi Tunnel on the Zhangtang Railway.In accordance with the...A ballastless slab track,which is commonly used in the track structures of heavy-haul railway tunnels,was analysed based on field measurement data of the Fuyingzi Tunnel on the Zhangtang Railway.In accordance with the measured data,the dynamic load thresholds and distributions on the surface and bottom of the ballastless slab track were investigated.A fatigue damage analysis of the ballastless slab track was performed based on the dynamic load time–history curve.The results show that the ballastless slab track can accomplish train load attenuation and reduce the dynamic load from heavy-haul trains by 47.22%from the surface to the bottom.In addition,the distribution at the bottom of the ballastless slab track exhibited a triangular shape,and the dynamic load threshold at the line centre accounted for 78.67%of that at the track position.Meanwhile,the distribution at the surface was saddle-shaped;the dynamic load threshold at the track position accounted for 79.55%of that at the line centre position.The fatigue damage of the ballastless slab track was analysed effectively by combining the measured data and the linear fatigue damage theory.Moreover,the accuracy of the calculation results was verified based on the measured dynamic stress of the ballastless slab track structure.The dynamic action of the train load led to more-concentrated damage to the track bed,and the damage occurred earlier than that in the ordinary line.The axle load was the primary influencing factor of the track bed fatigue damage,and the damage mainly occurred in the track position.These results provide a theoretical basis for performing stress analysis and designing parameters for ballastless slab tracks in heavy-haul railway tunnels.展开更多
In a seminal work, Gozar et al. reported on the high-temperature interface superconductivity in bilayers of insulating La2Cu O4 and metallic La2-xSrxCuO4(x=0.45). An interesting question to address is how general and ...In a seminal work, Gozar et al. reported on the high-temperature interface superconductivity in bilayers of insulating La2Cu O4 and metallic La2-xSrxCuO4(x=0.45). An interesting question to address is how general and robust this interface superconductivity is. In the past, the cuprate bilayers were grown in a unique atomic-layer molecular beam epitaxy system, with a Sr doping range of x≤0.47, and the atomically flat interface was thought to be indispensable. Here, we have fabricated bilayers of La2CuO4 and La2-xSrxCuO4 by pulsed laser deposition. We have tried to extend the nominal doping range of Sr from the previous maximum of 0.47 to the present1.70(the nominal Sr content in the targets). X-ray diffraction result indicates that our La2-xSrxCuO4 films with x≤0.60 have very high crystalline quality;but the film crystalline structure degrades gradually with further increasing x, and finally the structure is fully lost when x reaches 1.40 and higher. Although the film quality scatters dramatically, our experiments show that there exists superconductivity for bilayers in nearly the entire over-doped Sr range, except for a non-superconducting region at x^0.80. These observations demonstrate that the interface superconductivity in copper oxides is very general and robust.展开更多
基金partly funded by the National Key Research Program of China(2019YFA0708603)the National Natural Science Foundation of China(42130801,41230311,41572069,41702070)+2 种基金the 111 Project of the Ministry of Science and Technology,China(BP0719021)the MOST Special Fund from the State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences(MSFGPMR201804)the Key Laboratory of Gold Mineralization Processes and Resource Utilization Subordinated to the Ministry of Natural Resources and Key Laboratory of Metallogenic Geological Process and Resources Utilization in Shandong Province,Shandong Institute of Geological Sciences(KFKT201801,KFKT201802)。
文摘The current margins of the North China and Yangtze Cratons provide arguably the best examples globally of anomalously high mineral endowment within a 100 km buffer zone,hosting 66 diverse world-class to giant ore systems that help explain China’s premier position as a producer of multiple metal and mineral commodities.After the cratonization of these crustal blocks during the Neoarchean-Paleoproterozoic,with incorporation of iron ores on assembled micro-block margins,the margins of the cratons experienced multiple convergence and rifting events leading to metasomatism and fertilization of their underlying sub-continental lithospheric mantle.The rifted margins with trans-lithosphere faults provided pathways for Cu-Au(Mo-W-Sn)-bearing felsic to Ni-Cu-bearing ultrabasic intrusions and REE-rich carbonatite magmas,and for the development of marginal sedimentary basins with both Cu-Pb-Zn-rich source units and reactive carbonate or carbonaceous host rocks.There was diachronous formation of hydrothermal orogenic gold,antimony,and bismuth systems in the narrow orogenic belts between the cratons.Complexity in the Mesozoic Paleo-Pacific subduction systems resulted in asthenosphere upwelling and lithosphere extension and thinning in the North China Craton,leading to anomalous heat flow and formation of orogenic gold deposits,including those of the giant Jiaodong gold province on its north-eastern margin.These gold deposits,many of which formed from fluids liberated by devolatilization of previously metasomatized sub-continental lithospheric mantle,helped propel China to be the premier gold producer globally.The thick sub-continental lithospheric mantle of the cold buoyant cratons helped the preservation of some of the world’s oldest porphyry-skarn and epithermal mineral systems.Although craton margins globally control the formation and preservation of a diverse range of mineral deposits,China represents the premier example in terms of metal endowment due to the anomalous length of its craton margins combined with their abnormally complex tectonic history.
基金financial supports from the National Natural Science Foundation of China(No.51675433)the Natural Science Foundation for Distinguished Young Scholars of Shaanxi Province,China(No.2019JC-09)。
文摘To reveal the affecting mechanism of cooling rate on lamellarαprecipitation,the precipitation behaviors of lamellarαphase in IMI834 titanium alloy during isothermal and non-isothermal heat treatments were quantitatively characterized using experimental analysis.Critical precipitation temperatures at various cooling rates were obtained using thermal dilatation testing.Using metallographic microscopy,electron microprobe analysis,and data fitting methods,the quantitative evolution models of average width,volume fraction,and solute concentration in theαandβphases were built for different temperatures or cooling rates.A comparison between the two precipitation behaviors showed that the average width and volume fraction of lamellarαphase under non-isothermal conditions were smaller than those under isothermal conditions.With increasing cooling rate,the average width and volume fraction were decreased significantly,and the critical precipitation temperatures were reduced.This phenomenon is mainly attributed to the decreased diffusion velocity of solutes Al,Mo,and Nb with increasing cooling rate.
文摘There are large volumes of the Phanerozoic granitoid rocks in China and neighboring areas.In recent years,numerous new and precise U-Pb zircon ages have been published for these granitoids,and define many important magmatic events,such as ca.500 Ma granitoid events in the West Junggar,Altai orogens in the NW China,and Qinling orogen in the central China.These ages accurately constrain the time of important early Paleozoic,late Paleozoic,early Mesozoic and late Mesozoic magmatic events of the northern,central,western,southern and eastern orogenic Mountains in China.There occur various types of granitoids in China,such as talc-alkaline granite,alkali granite,highly-fractionated granite,leucogranite, adakite,and rapakivi granite.Rapakivi granites are not only typical Proterozoic as in the North China Craton,but were also emplaced during Paleozoic and Mesozoic in the Kunlun-Qinling orogen,a part of the China Central Orogenic Belt (CCOB).Nd-Hf isotopic tracing and mapping show that granitoids inthe southern Central Asian Orogenic Belt (CAOB)in China (or the Northern China Orogenic Belt)are characterized predominantly by juvenile sources.The juvenile crust in this orogenic domain accounts for over 50% by area,distinguishing it from other orogenic belts in the world,and those in central (e.g.,Qinling),southwestem and eastern China.Based on a large amount of new age data,a preliminary granitoid and granitoid-tectonic maps of China have been preliminarily compiled,and an evolutionary framework of Phanerozoic granitoids in China and neighboring areas has been established from the view of assembly and breakup of continental blocks.Research ideas on granitoid tectonics has also been proposed and discussed.
基金financially supported by the Second Tibetan Plateau Scientific Expedition and Research (2019QZKK0801)the National Natural Science Foundation of China (NSFC programs 41772088, 41773042 and 41773043)the Geological Survey Project (DD20190001).
文摘1.Objectives The porphyry copper deposits (PCD) are usually hosted in a multistage intrusive complex but only causallyrelated tospecific magma of high oxidation state and water content. The copper enrichment of the porphyry system is caused by accumulation during magmatic differentiation (Hou ZQ et al., 2015). Thus, study on magmatic evolution and Cu mineralization process is important for understanding the formation of PCD.
基金Project supported by the National Basic Research Program of China(Grant Nos.2016YFA0300701,2017YFA0206300,2017YFA0303601,and2018YFA0305704)the National Natural Science Foundation of China(Grant Nos.11520101002,51590880,11674378,11934016,and 51972335)the Key Program of the Chinese Academy of Sciences。
文摘The electric gating on the transport properties of two-dimensional electron gas(2DEG) at the interface of LaAlO_(3)/SrTiO_(3)(LAO/STO) heterostructure has attracted great research interest due to its potential application in fieldeffect devices. Most of previous works of gate effect were focused on the LAO/STO heterostructure containing only one conductive interface. Here, we systematically investigated the gate effect on high-quality LAO/STO superlattices(SLs)fabricated on the TiO_(2)-terminated(001) STO substrates. In addition to the good metallicity of all SLs, we found that there are two types of charge carriers, the majority carriers and the minority carriers, coexisting in the SLs. The sheet resistance of the SLs with a fixed thickness of the LAO layer increases monotonically as the thickness of the STO layer increases. This is derived from the dependence of the minority carrier density on the thickness of STO. Unlike the LAO/STO heterostructure in which minority and majority carriers are simultaneously modulated by the gate effect, the minority carriers in the SLs can be tuned more significantly by the electric gating while the density of majority carriers is almost invariable. Thus, we consider that the minority carriers may mainly exist in the first interface near the STO substrate that is more sensitive to the back-gate voltage, and the majority carriers exist in the post-deposited STO layers. The SL structure provides the space separation for the multichannel conduction in the 2 DEG, which opens an avenue for the design of field-effect devices based on LAO/STO heterostructure.
基金the National Natural Science Foundation of China (Nos. 21071068 and 21372107)the Fundamental Research Funds for the Central Universities (No. lzujbky-2012-k08)
文摘A direct asymmetric tandem reaction of a-nitro ketones with b g-unsaturated a-ketoesters was found to be catalyzed by a bifunctional rosin-derived thiourea and gave 5-nitro-2-actoxyl-2-pentenates in excellent ee values and yields,a much better result than previously reported.Furthermore,through theoretical analysis,literature research and experimental verifications,a new mechanism involving an inverse-electron-demand Diels–Alder（IEDDAR） and a retro-Henry reaction was proposed.
基金supported by the National Natural Science Foundation of China(82260655)the National Key Research and Development Program of People’s Republic of China(Grant No.2021YFC2300800 and 2021YFC2300804)+1 种基金the Basic and applied basic research project jointly funded by the University of Guangzhou(Grant No.2023A03J0810)the Key R&D Program of Guangdong Province(Grant No.2022B1111030002).
文摘Background Dengue is a major global health threat with varied clinical manifestations across age groups,countries,and regions.This study aims to estimate global dengue disability weights(DWs)based on clinical manifestations data and examine variations across different demographics and geographical areas.These findings will inform public health strategies and interventions to reduce the global burden of dengue.Methods We conducted a systematic search across six databases(Scopus,Web of Science,PubMed,China National Knowledge Infrastructure,Wanfang Data,and Database of Chinese sci-tech periodicals)for studies on human dengue clinical manifestations or infection from the establishment of each database through December 31,2023.DWs were estimated by combining clinical manifestations frequencies with corresponding DW values derived from the Global Burden of Disease(GBD)study,using Monte Carlo simulations to generate uncertainty intervals.Odds ratios(ORs)with 95%confidence intervals(CI)and Chi-square tests were performed to compare clinical manifestations between adults and children.Results A total of 35 adult studies(7109 cases)and 17 pediatric studies(2996 cases)were analysed.Adults had higher rates of muscle pain(OR=9.18;95%CI:8.17–10.33)and weak(OR=4.95;95%CI 4.12–5.98).Children showed higher frequencies of decreased appetite(OR=0.12;95%CI:0.11–0.14)and lymphadenectasis(OR=0.04;95%CI:0.03–0.06).Severe dengue was more prevalent in children(8.2%)than adults(4.6%).The global DW for universal dengue was 0.3258 in adults and 0.4022 in children,with Indian children showing the highest DW for severe dengue(0.6991)and Chinese adult showing the highest DW for severe dengue(0.7214).Regionally,most studies were from South and Southeast Asia,with India contributing the largest number of publications(80 articles).Additionally,India had the highest dengue disease burden in 2021(352,468.54 person-years).Conclusions These findings reveal important age and regional differences in dengue disease burden.There is a relative lack of research on dengue clinical manifestations in several high-burden countries in the Americas,and these gaps may affect the comprehensiveness and accuracy of global dengue disability weight estimates.These highlight the urgent need for targeted interventions and optimized resource allocation to mitigate its global impact.
基金supported by the National Natural Science Foundation of China(Grant No.81673828)
文摘Diarrhea can occur at an early or advanced stage of acquired immunodeficiency syndrome(AIDS)as a usual symptom in people with human immunodeficiency virus(HIV)infection.While it is usually not fatal,it can influence patients’quality of life seriously.It has shown to be efficacious and improves people’s immune status to a certain extent to treat HIV/AIDS-related diarrhea on the basis of syndrome differentiation and treatment or Chinese herbs plus conventional treatment.Therefore,it may have a good application potential.Here,we outline a protocol for the systematic review of this health-care intervention,with the aim to evaluate the beneficial effects and safety of Traditional Chinese Medicine(TCM)for patients who suffer from HIV/AIDS-associated diarrhea.Randomized controlled trials that compare Chinese herbs with placebo or other effective treatments will be searched and included,in spite of publication status or language.The primary outcomes include diarrhea frequency and fecal character.The databases we will search as follows:China Science and Technology Journal Database(VIP),Chinese Biomedical Literature Database(Sino Med),Wanfang Data,China National Knowledge Infrastructure,Pub Med and the CENTRAL in Cochrane Library.Two authors will respectively conduct the screening of trials,data extraction,and use the Cochrane risk of bias tool to assess the methodological quality.We will analyze the data and perform a meta-analysis if possible.We intend to identify potential therapeutic modalities that may be of benefit to inform clinical practice by supplying existing evidence of the helpful effects and safety of TCM to treat patients suffering from HIV/AIDS-associated diarrhea.
基金the Open-end Fund of Key Laboratory of New Technology for Construction of Cities in Mountain Area(LNTCCMA-20210108)the National Natural Science Foundation of China(5108098)+5 种基金the Chongqing Education Commission Science and Technology Research Project(KJQN201901509)the Chongqing Natural Science Fund General Project(cstc2020jcyj-msxmX0904)the Chongqing Talents:Exceptional Young Talents Project(cstc2021ycjhbgzxm0246)the China Postdoctoral Science Foundation-General Project(2021M693739)Chongqing Talents:Exceptional Young Talents Project(cstc2021ycjhbgzxm0246)China Postdoctoral Science Foundation-General Project(2021M693739).
文摘A ballastless slab track,which is commonly used in the track structures of heavy-haul railway tunnels,was analysed based on field measurement data of the Fuyingzi Tunnel on the Zhangtang Railway.In accordance with the measured data,the dynamic load thresholds and distributions on the surface and bottom of the ballastless slab track were investigated.A fatigue damage analysis of the ballastless slab track was performed based on the dynamic load time–history curve.The results show that the ballastless slab track can accomplish train load attenuation and reduce the dynamic load from heavy-haul trains by 47.22%from the surface to the bottom.In addition,the distribution at the bottom of the ballastless slab track exhibited a triangular shape,and the dynamic load threshold at the line centre accounted for 78.67%of that at the track position.Meanwhile,the distribution at the surface was saddle-shaped;the dynamic load threshold at the track position accounted for 79.55%of that at the line centre position.The fatigue damage of the ballastless slab track was analysed effectively by combining the measured data and the linear fatigue damage theory.Moreover,the accuracy of the calculation results was verified based on the measured dynamic stress of the ballastless slab track structure.The dynamic action of the train load led to more-concentrated damage to the track bed,and the damage occurred earlier than that in the ordinary line.The axle load was the primary influencing factor of the track bed fatigue damage,and the damage mainly occurred in the track position.These results provide a theoretical basis for performing stress analysis and designing parameters for ballastless slab tracks in heavy-haul railway tunnels.
基金supported by the National Key Research and Development Program of Ministry of Science and Technology of China (2017YFA0303002, 2016YFA0300204, and 2016YFA0300701)the Fundamental Research Funds for the Central Universities
文摘In a seminal work, Gozar et al. reported on the high-temperature interface superconductivity in bilayers of insulating La2Cu O4 and metallic La2-xSrxCuO4(x=0.45). An interesting question to address is how general and robust this interface superconductivity is. In the past, the cuprate bilayers were grown in a unique atomic-layer molecular beam epitaxy system, with a Sr doping range of x≤0.47, and the atomically flat interface was thought to be indispensable. Here, we have fabricated bilayers of La2CuO4 and La2-xSrxCuO4 by pulsed laser deposition. We have tried to extend the nominal doping range of Sr from the previous maximum of 0.47 to the present1.70(the nominal Sr content in the targets). X-ray diffraction result indicates that our La2-xSrxCuO4 films with x≤0.60 have very high crystalline quality;but the film crystalline structure degrades gradually with further increasing x, and finally the structure is fully lost when x reaches 1.40 and higher. Although the film quality scatters dramatically, our experiments show that there exists superconductivity for bilayers in nearly the entire over-doped Sr range, except for a non-superconducting region at x^0.80. These observations demonstrate that the interface superconductivity in copper oxides is very general and robust.
