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46篇 您的检索式:作者名="YAN JunHua"
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1Climate and litter C/N ratio constrain soil organic carbon accumulation显示文摘Soil organic carbon(SOC) plays critical roles in stabilizing atmospheric CO2 concentration, but the mechanistic controls on the amount and distribution of SOC on global scales are not well understood. In turn, this has hampered the ability to model global C budgets and to find measures to mitigate climate change. Here, based on the data from a large field survey campaign with 2600 plots across China’s forest ecosystems and a global collection of published data from forested land, we find that a low litter carbon-to-nitrogen ratio(C/N) and high wetness index(P/PET, precipitation-to-potentialevapotranspiration ratio) are the two factors that promote SOC accumulation, with only minor contributions of litter quantity and soil texture. The field survey data demonstrated that high plant diversity decreased litter C/N and thus indirectly promoted SOC accumulation by increasing the litter quality. We conclude that any changes in plant-community composition, plant-species richness and environmental factors that can reduce the litter C/N ratio, or climatic changes that increase wetness index, may promote SOC accumulation. The study provides a guideline for modeling the carbon cycle of various ecosystem scales and formulates the principle for land-based actions for mitigating the rising atmospheric CO2 concentration.Guoyi Zhou Shan Xu Philippe Ciais Stefano Manzoni Jingyun Fang Guirui Yu Xuli Tang Ping Zhou Wantong Wang Junhua Yan Gengxu Wang Keping Ma Shenggong Li Sheng Du Shijie Han Youxin Ma Deqiang Zhang Juxiu Liu Shizhong Liu Guowei Chu Qianmei Zhang Yuelin Li Wenjuan Huang Hai Ren Xiankai Lu Xiuzhi Chen 2019National Science Review2019,6,4:21
2Traditional Chinese medicine in COVID-19显示文摘COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2(SARSCo V-2)has spread across the globe,posing an enormous threat to public health and safety.Traditional Chinese medicine(TCM),in combination with Western medicine(WM),has made important and lasting contributions in the battle against COVID-19.In this review,updated clinical effects and potential mechanisms of TCM,presented in newly recognized three distinct phases of the disease,are summarized and discussed.By integrating the available clinical and preclinical evidence,the efficacies and underlying mechanisms of TCM on COVID-19,including the highly recommended three Chinese patent medicines and three Chinese medicine formulas,are described in a panorama.We hope that this comprehensive review not only provides a reference for health care professionals and the public to recognize the significant contributions of TCM for COVID-19,but also serves as an evidence-based in-depth summary and analysis to facilitate understanding the true scientific value of TCM.Ming Lyu Guanwei Fan Guangxu Xiao Taiyi Wang Dong Xu Jie Gao Shaoqin Ge Qingling Li Yuling Ma Han Zhang Jigang Wang Yuanlu Cui Junhua Zhang Yan Zhu Boli Zhang 2021Acta Pharmaceutica Sinica B2021,11,11:14
3Nitrogen Deposition and Its Spatial Pattern in Main Forest Ecosystems along North-South Transect of Eastern China显示文摘A continuous three-year observation(from May 2008 to April 2011)was conducted to characterize the spatial variation of dissolved inorganic nitrogen(DIN)deposition at eight main forest ecosystems along the north-south transect of eastern China(NSTEC).The results show that both throughfall DIN deposition and bulk DIN deposition increase from north to south along the NSTEC.Throughfall DIN deposition varies greatly from 2.7 kg N/(ha·yr)to 33.0 kg N/(ha·yr),with an average of 10.6 kg N/(ha·yr),and bulk DIN deposition ranges from 4.1 kg N/(ha·yr)to 25.4 kg N/(ha·yr),with an average of 9.8 kg N/(ha·yr).NH4+-N is the dominant form of DIN deposition at most sampling sites.Additionally,the spatial variation of DIN deposition is controlled mainly by precipitation.Moreover,in the northern part of the NSTEC,bulk DIN deposition is 17%higher than throughfall DIN deposition,whereas the trend is opposite in the southern part of the NSTEC.The results demonstrate that DIN deposition would likely threaten the forest ecosystems along the NSTEC,compared with the critical loads(CL)of N deposition,and DIN deposition in this region is mostly controlled by agricultural activities rather than industrial activities or transportation.ZHAN Xiaoyun YU Guirui HE Nianpeng FANG Huajun JIA Bingrui ZHOU Mei WANG Chuankuan ZHANG Junhui ZHAO Guangdong WANG Silong LIU Yunfen YAN Junhua 2014Chinese Geographical Science2014,24,2:10
4A new paleoenvironmental index for anoxic events—Mo isotopes in black shales from Upper Yangtze marine sediments显示文摘This paper investigates the high-solution of Mo isotopes and uses trace-element analyses for fresh and representative black shales and siliceous shales collected from the transition between the Late Ordovician and the Early Silurian at the Wangjiawan section in Yichang and the Late Permian Dalong Formation in the Shangsi Section of Sichuan. The applicability of different geochemical parameters used as paleo-oxygenation indices are also compared. The preliminary results show that V/(V+Ni), U auth (auth U), V/Cr, Ce anom and U/Th have a scattered variation range, but most samples plot within the suboxic-anoxic fields. The suboxic-anoxic environment was dominant during the deposition and formation of the two anoxic facies. These redox indicators show little correspondence to the δ 98 Mo values. The U/Mo ratio can be used as a potential proxy for the paleo-redox conditions due to the possibility that Mo is enriched relative to U at different redox gradients during early diagenesis. This evidence is more significant for the euxinicity condition and corresponds to positive δ 98 Mo (>1.5‰) values with low U/Mo ratios. This evidence is likely related to the depositional conditions near the boundary between anoxic and euxinic environments, which are characterised by low bioturbation or water circulation. Other samples reveal a wide scatter of U/Mo ratios and δ 98 Mo <1.5‰. These results are likely due to punctuated improvements in oxygenation with intense bioturbation or water circulation, which led to the redistribution of trace element.ZHOU Lian SU Jie HUANG JunHua YAN JiaXing XIE XiNong GAO Shan DAI MengNing Tonger 2011Science China Earth Sciences2011,54,7:9
5Aboveground biomass and corresponding carbon sequestration ability of four major forest types in south China显示文摘We estimated aboveground biomass carbon (TABC) and net carbon accumulation rates (TNEP) for trees in four major forest types based on national forest inventory data collected in 1994-1998 and 1999-2003. The four types were Pinus massoniana forest, Cunninghamia lanceolata forest, hard broad-leaved evergreen forest and soft broad-leaved evergreen forest. We analyzed variations in TABC and TNEP for five stand ages (initiation, young, medium, mature and old). In both time periods, estimated TABC in all four forest types increased consistently with forest stand age and the oldest stage had the largest TABC compared with other stages. Broad-leaved forests (hard and soft) had higher TABC than needle-leaved forests (Pinus massoniana and Cunninghamia lanceolata) for each of the five age stages. The difference of TABC between broad-leaved and needle-leaved forests increased with forest stand age. Comparison of estimated TNEP by age category indicated TNEP increased from the initiation stage to the young stage, and then decreased from the mature stage to old stage in all four forest types. TNEP for any particular stage depended on the forest type; for instance, broad-leaved forests at both the mature and old stages had greater TNEP than in needle-leaved forests. A logistic curve was applied to fit the relationship between TABC and forest stand age. In each period, correlations in all four forest types were all statistically significant (P < 0.01) with R2 > 0.95. TABC was therefore predicted by these regression functions from 2000 to 2050 and the mean TNEP during the predicted period was estimated to be about 41.14, 31.53, 75.50 and 75.68 gCm-2a-1 in Pinus massoniana forest, Cunninghamia lanceolata forest, hard broad-leaved forest and soft broad-leaved forest, respectively. Results from both forest inventory and regression prediction suggest broad-leaved forests are greater carbon sinks, and hence have greater carbon sequestration ability especially in the mature and old stages when compared to needle-leaved forests. Broad-leaved forests should have high levels of carbon sequestration when compared with needle-leaved forests in south China.CHEN QingQing XU WeiQiang LI ShengGong FU ShengLei YAN JunHua 2013Chinese Science Bulletin2013,58,13:8
6Clinical practices s of Traditional Chinese Medicine for acute upper respiratory tract infection in children显示文摘OBJECTIVE:To develop Clinical practice s of Traditional Chinese Medicine(TCM) for acute upper respiratory tract infection(AURI) in children;TCM is usedalone or administered together with antibiotics.METHODS:Under the guidance of evidence-based medicine concept,in strict accordance with the rules of international s development,as well as on the basis of evidence of clinical research of TCM,the s solicited opinions from clinical experts and methodologists in TCM and Western Medicine.GRADE standard was applied to form experts' consensus.RESULTS:The s standardized classification of TCM patterns and TCM treatments in children with AURI,including prescription,Chinese patent medicine,non-drug treatment and prevention.CONCLUSION:Follows the principle of 'evidence based,consensus supplemented,and experience referred',these s were formulated,but the quality of evidence of included studies were relatively low.Further refinement of the s should be needed as deeper clinical studies as available in future.Rong Ping Li Li Zhang Xilian Liu Quanhui Yan Huimin Xin Deli Xue Zheng Ren Xianqing Wu Zhenqi Ma Rong Zhang Junhua 2018Journal of Traditional Chinese Medicine2018,38,4:7
7Geobiological approach to evaluating marine carbonate source rocks of hydrocarbon显示文摘Evaluating the pre-Jurassic marine source rocks in China has been difficult because these rocks are generally too highor over-maturated for most traditional methods to work.As to the remaining parameter TOC (%),its lower limit for recognizing the carbonate source rocks in China has been in dispute.Nineteen Phanerozoic sections in the Middle-Upper Yangtze Platform and the Guizhou-Hunan-Guangxi Basin have been studied in search for a different approach to complementing the traditional evaluation method for these source rocks.We have applied a geobiological approach to tracing the organic carbon (OC) output and accumulation from the living stage (primary productivity) to the post-mortem deposited remains,and finally to the preserved burial organics.Four biological and geological parameters are employed to represent the OC of the three stages.A series of proxies of these parameters are discussed and integrated to establish a geobiological evaluation system independent of TOC and other traditional methods.Here we use the Guangyuan section in Sichuan as an example for the geobiological evaluation.Our results indicate that in the argillaceous rocks,the geobiological parameters show the qualified source rocks in accordance with high TOC values;but in the carbonates,the good source rocks delineated by the geobiological parameters have a wide range of TOC,from 0.03% to 1.59%,mostly<0.3%.We suggest that it is still premature to set TOC=0.3% or 0.5% as the lower limit for the pre-Jurassic carbonate source rocks in South China.YIN HongFu XIE ShuCheng YAN JiaXin HU ChaoYong HUANG JunHua Tenger QIE WenKun QIU Xuan 2011Science China Earth Sciences2011,54,8:7
8Effect of W on microstructure of high strength and toughness steels显示文摘The effect of W on the microstructure and the mechanical properties of ultrahigh strength low alloy steels was carried out. The microstructure of 30Cr3Si2Mn2NiMoNb and 30Cr3Si2Mn2NiMoNbW steels under quenched conditions were investigated by metallographic microscope, scanning electron microscope (SEM), X-ray diffraction (XRD), and transmission electron microscope (TEM). Thermodynamic calculation was also conducted. The results showed that the addition of W made undissolved carbides more and finer, which exerted strong pinning force on migrating packet boundary and improved tensile strength significantly. M 6 C particles in 30Cr3Si2Mn2NiMoNb steel were disappeared above 1193 K, while the M 6 C particles in 30Cr3Si2Mn2NiMoNbW steel were disappeared above 1253 K, the calculation results were in agreement with the experimental.Yan LU Jie SU Junhua WANG Gang XIE Zhuoyue YANG 2011Acta Metallurgica Sinica(English Letters)2011,24,6:4
9Effects of precipitation on soil organic carbon fractions in three subtropical forests in southern China显示文摘Aims The aim of this study was to investigate the effects of precipitation changes on soil organic carbon(SOC)fractions in subtropical forests where the precipitation pattern has been altered for decades.Methods We conducted field manipulations of precipitation,including ambient precipitation as a control(CK),double precipitation(DP)and no precipitation(NP),for 3 years in three forests with different stand ages(broadleaf forest[BF],mixed forest[MF]and pine forest[PF])in subtropical China.At the end of the experiment,soil samples were collected to assay SOC content,readily oxidizable organic carbon(ROC)and non-readily oxidizable organic carbon(NROC),as well as soil microbial biomass carbon(MBC),pH and total nitrogen content.Samples from the forest floors were also collected to analyze carbon(C)functional groups(i.e.alkyl C,aromatic C,O-alkyl C and carbonyl C).Furthermore,fine root biomass was measured periodically throughout the experiment.Important Findings Among the forests,ROC content did not exhibit any notable differences,while NROC content increased significantly with the stand age.This finding implied that the SOC accumulation observed in these forests resulted from the accumulation of NROC in the soil,a mechanism for SOC accumulation in the mature forests of southern China.Moreover,NP treatment led to significant reductions in both ROC and NROC content and therefore reduced the total SOC content in all of the studied forests.Such decreases may be due to the lower plant-derived C inputs(C quantity)and to the changes in SOC components(C quality)indicated by C functional groups analyses under NP treatment.DP treatment in all the forests also tended to decrease the SOC content,although the decreases were not statistically significant with the exception of SOC and ROC content in PF.This finding indicated that soils in MF and in BF may be more resistant to precipitation increases,possibly due to less water limitations under natural conditions in the two forests.Our results therefore highlight the different responses of SOC and its fractions to precipitation changes among the forests and suggest that further studies are needed to improve our understanding of SOC dynamics in such an important C sink region.Xiaomei Chen Deqiang Zhang Guohua Liang Qingyan Qiu Juxiu Liu Guoyi Zhou Shizhong Liu Guowei Chu Junhua Yan 2016Journal of Plant Ecology2016,9,1:4
10Formation and crystallization behavior of Fe-based amorphous precursors with pre-existingα-Fe nanoparticles-Structure and magnetic properties of high-Cu-content Fe-Si-B-Cu-Nb nanocrystalline alloys显示文摘Structure,crystallization behavior,and magnetic properties of as-quenched and annealed Fe_(81.3)Si_(4)O_(13)Cu_(1.7)(Cu1.7)alloy ribbons and effects of Nb alloying have been studied.Three-dimensional atom probe and transmission electron microscopy analyses reveal that high-number-density Cu-clusters and Pre-existing Nano-sized a-Fe Particles(PN-a-Fe)are coexistence in the melt-spun Cu1.7 amorphous matrix,and the PN-α-Fe form by manners of one-direction adjoining and enveloping the Cu-clusters.Two-step crystallization behavior associated with growth of the PN-a-Fe and subsequent nucleation and growth of newly-formedα-Fe is found in the primary crystallization stage of the Cu1.7 alloy.The number densities of the Cu-clusters and PN-a-Fe in melt-spun Fe8_(1.3-x)Si_(4)B_(13)Cu_(1.7)Nb_(x)alloys are gradually reduced with enriching of Nb,and a fully amorphous structure forms at 4 at.%Nb,although smaller Cu-clusters still exist.After annealing,2 at.%Nb coarsens the average size(D_(α-F)e)of theα-Fe grains from 14.0 nm of the Nb-free alloy to 21.6 nm,and 4 at.%Nb refines the D_(α-Fe)to 8.9 nm.The mechanisms of theα-Fe nucleation and growth during quenching and annealing for the alloys with large quantities of PN-α-Fe as well as after Nb alloying have been discussed,and an annealing-induced oc-Fe growth mechanism in term of the barrier co-contributed by competitive growth among the PN-a-Fe and diffusion-suppression effect of Nb atoms has been proposed.A coercivity(HC)αDα-Fe^(3)correlation has been found for the nanocrystalline alloys,and the permeability is inverse with the H_(C).Yanhui Li Xingjie Jia Wei Zhang Yan Zhang Guoqiang Xie Zhiyong Qiu Junhua Luan Zengbao Jiao 2021Journal of Materials Science & Technology2021,,6:3
11Unveiling the roles of interspecific competition and local adaptation in phenotypic differentiation of parapatric frogs显示文摘Understanding how ecological processes affect phenotypic evolution has been and continues to be an important goal of ecology and evolutionary biology. Interspecific competition for resources can be a selective force driving phenotypic differentiation that reduces competition among sympatric species (character divergence), enabling closely-related species to coexist. However, although patterns of character divergence are well documented in both empirical and theoretical researches, how local adaptation to abiotic environment affects trait evolution in the face of interspecific competition is less known. Here, we investigate how patterns in morphological traits of 2 parapatric frog species, Feirana quadranus and F. taihangnica, vary among allopatric and sympatric regions using range-wide data derived from extensive field surveys. Feirana quadranus was overall larger than F. taihangnica in body size (i.e., snout-vent length [SVL]), and the difference between SVL of both species in sympatry was larger than that in allopatry. From allopatry to sympatry, the 2 species diverged in foot and hand traits, but converged in eye size and interorbital span, even when we controlled for the effects of geographic gradients. Sympatric divergence in SVL, hand and foot traits is likely acting as a case of evolutionary shift caused by interspecific competition. In contrast, sympatric convergence of eye-related traits may derive at least partly from adaptation to local environments. These results imply the relative roles of interspecific competition and local adaptation in shaping phenotypic diversification. Our findings illustrate how traits evolve in parapatric species pair due to sympatric divergent and convergent evolution. It thus provides insights into understanding underlying evolutionary processes of parapatric species, that is, competition and local adaptation.Yan HUANG Xiaoyi Wang Xin Yang Jianping Jiang Junhua Hua 2020Current Zoology2020,66,4:2
12Role of Fe oxides in corrosion of pipeline steel in a red clay soil显示文摘Maocheng Yan Cheng Sun Jin Xu Junhua Dong Wei Ke 2013Corrosion Science2013,,:1
13Recent advances based on Mg anodes and their interfacial modulation in Mg batteries显示文摘Magnesium(Mg)batteries(MBs),as post-lithium-ion batteries,have received great attention in recent years due to their advantages of high energy density,low cost,and safety insurance.However,the formation of passivation layers on the surface of Mg metal anode and the poor compatibility between Mg metal and conventional electrolytes during charge-discharge cycles seriously affect the performance of MBs.The great possibility of generating Mg dendrites has also caused controversy among researchers.Moreover,the regulation of Mg deposition and the enhancement of battery cycle stability is largely limited by interfacial stability between Mg metal anode and electrolyte.In this review,recent advances in interfacial science and engineering of MBs are summarized and discussed.Special attention is given to interfacial chemistry including passivation layer formation,incompatibilities,ion transport,and dendrite growth.Strategies for building stable electrode/interfaces,such as anode designing and electrolyte modification,construction of artificial solid electrolyte interphase(SEI)layers,and development of solid-state electrolytes to improve interfacial contacts and inhibit Mg dendrite and passivation layer formation,are reviewed.Innovative approaches,representative examples,and challenges in developing high-performance anodes are described in detail.Based on the review of these strategies,reference is provided for future research to improve the performance of MBs,especially in terms of interface and anode design.Fanfan Liu Guoqin Cao Jinjin Ban Honghong Lei Yan Zhang Guosheng Shao Aiguo Zhou Li zhen Fan Junhua Hu 2022Journal of Magnesium and Alloys2022,10,10:1
14Estimates of soil respiration and net primary production of three forests at different succession stages in South China 显示文摘Yan Junhua Wang Yingping Zhou Guoyi 2006Global Change Biology2006,12,:1
15Direct growth of hexagonal boron nitride films on dielectric sapphire substrates by pulsed laser deposition for optoelectronic applications显示文摘Recently,hexagonal boron nitride(h-BN),an ultra-wide bandgap semiconductor,has attracted considerable atten-tion owing to its excellent properties.In thin films grown on metal catalysts,contamination and damage induced by a transfer process cannot be avoided.Therefore,synthesizing h-BN films on non-catalytic dielectric substrates is desirable for electronic applications.In this study,we demonstrate the direct growth of high-quality h-BN films with a controllable thickness on sapphire substrates by using the pulsed laser deposition(PLD)technique.The effects of the deposition conditions and laser parameters on the growth of the h-BN films are systematically investigated by evaluating their characteristic Raman peaks.Among the various growth parameters studied,the substrate temperature has the greatest influence on the crystalline quality of the h-BN films,and the optimal pres-sure varies depending on the target-substrate distance.The h-BN film grown under optimal conditions exhibits a narrow Raman line width of∼30 cm^(−1),indicating a high crystalline quality.The photodetectors fabricated from the PLD-grown h-BN films exhibit superior deep-ultraviolet detection performance with a large on/offratio of>104,high photoresponsivity,and a sharp cut-offwavelength of 220 nm.This study presents the possibility of producing high-quality h-BN films by applying PLD on dielectric substrates for optoelectronic applications.Gaokai Wang Jingren Chen Junhua Meng Zhigang Yin Ji Jiang Yan Tian Jingzhen Li Jinliang Wu Peng Jin Xingwang Zhang 2021Fundamental Research2021,1,6:1
16A reliable intelligent system for real-time dynamic security assessment of power systems显示文摘Xu Yan Dong Zhaoyang Zhao Junhua 2012IEEE Transactions on Power Systems2012,27,3:1
17Coordinated Control of Fine-Particle and Ozone Pollution by the Substantial Reduction of Nitrogen Oxides显示文摘1.Introduction In recent years,the air quality in China has improved significantly.In many cities,however,the concentration of fine particulate matter(PM_(2.5))remains higher than the secondary-level national ambient air quality standard(NAAQS level-2,35μg·m^(-3),GB3095-2012[1])and much higher than the first-level NAAQS(15μg·m^(-3),GB3095-2012[1])and the World Health Organization(WHO)air quality guidelines(5μg·m^(-3)).Biwu Chu Yan Ding Xiang Gao Junhua Li Tingyu Zhu Yunbo Yu Hong He 2022Engineering2022,8,8:1
18Potential Treatment of COVID-19 with Traditional Chinese Medicine: What Herbs Can Help Win the Battle with SARS-CoV-2?显示文摘Traditional Chinese medicine(TCM)has been successfully applied worldwide in the treatment of coronavirus disease 2019(COVID-19),which is caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2).However,the pharmacological mechanisms underlying this success remain unclear.Hence,the aim of this review is to combine pharmacological assays based on the theory of TCM in order to elucidate the potential signaling pathways,targets,active compounds,and formulas of herbs that are involved in the TCM treatment of COVID-19,which exhibits combatting viral infections,immune regulation,and amelioration of lung injury and fibrosis.Extensive reports on target screening are elucidated using virtual prediction via docking analysis or network pharmacology based on existing data.The results of these reports indicate that an intricate regulatory mechanism is involved in the pathogenesis of COVID-19.Therefore,more pharmacological research on the natural herbs used in TCM should be conducted in order to determine the association between TCM and COVID-19 and account for the observed therapeutic effects of TCM against COVID-19.Lin Li Yuzheng Wu Jiabao Wang Huimin Yan Jia Lu Yu Wang Boli Zhang Junhua Zhang Jian Yang Xiaoying Wang Min Zhang Yue Li Lin Miao Han Zhang 2022Engineering2022,,12:1
19Temperature and precipitation control of the spatial variation of terrestrial ecosystem carbon exchange in the Asian region显示文摘Zhi Chen Guirui Yu Jianping Ge Xiaomin Sun Takashi Hirano Nobuko Saigusa Qiufeng Wang Xianjin Zhu Yiping Zhang Junhui Zhang Junhua Yan Huimin Wang Liang zhao Yanfen Wang Peili Shi Fenghua Zhao 2013Agricultural and Forest Meteorology2013,,:1
20Multi- criteria decision making method based on possibility degree of interval type-2 fuzzy number显示文摘Junhua Hu Yan Zhang Xiaohong Chen 2013Knowledge- Based Systems2013,43,5:1
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