|
|
|
题名
|
作者
|
年代
|
出处
|
被引量
|
| 1 | Climate 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 | 2019 | National Science Review2019，6，4： | 21 |
| 2 | Characteristics of Settings and Etiologic Agents of Foodborne Disease Outbreaks—China,2020显示文摘Introduction:Foodborne diseases are a growing public health problem and have caused a large burden of disease in China.This study analyzed epidemiological characteristics of foodborne diseases in China in 2020 to provide a scientific basis for prevention and control measures.Methods:Data were collected from 30 of 31 provincial-level administrative divisions(PLADs)in the mainland of China,excluding Xizang(Tibet)Autonomous Region,via the National Foodborne Disease Outbreaks Surveillance System・The number and proportion of outbreaks,illnesses,hospitalizations,deaths by setting,pathogen-food category pairs and etiology were calculated.Results:In 2020,7,073 foodborne disease outbreaks were reported,resulting in 37,454 illnesses and 143 deaths.Among the identified pathogens,microbial pathogens were the most common confirmed etiology,accounting for 41.7%of illnesses.Poisonous mushrooms caused the largest proportion of outbreaks(58.0%)and deaths(57.6%).For venues where foodborne disease outbreaks occur,household had the highest number of outbreaks(4,140)and deaths(128),and catering service locations caused the largest proportion of illnesses(59.9%).Outbreaks occurring between June and September accounted for 62.8%of total outbreaks.Conclusions:Foodborne disease outbreaks mainly occurred in households・Microbial pathogens remained the top cause of outbreak-associated illnesses.Poisonous mushrooms were ranked the top cause of deaths in private homes in China.The supervision and management of food safety and health education should be strengthened to reduce the burden of foodborne diseases・Publicity should be increased to reduce the incidence of mushroom poisonings in families,and supervision and management of food should be strengthened to reduce microbial contamination. | Hongqiu Li Weiwei Li Yue Dai Yuyan Jiang Junhua Liang Santao Wang Maoqiang Zhuang Zheng Huang Lizi Xu Bo Xue Jikai Liu Haihong Han Sara M.Pires Ping Fu Yunchang Guo | 2021 | China CDC weekly2021，3，42： | 14 |
| 3 | Numerical simulation of gas flow process in mining-induced crack network显示文摘The exploitation of coal bed methane or coal gas is one of the most effective solutions of the problem of coal gas hazard.A better understanding of gas flow in mining-induced cracks plays an important role in comprehensive development and utilization of coal gas as well as prevention of coal gas hazard.This paper presents a case study of gas flow in mining-induced crack network regarding the situation of low permeability of coal seam.A two-dimensional physical model is constructed on the basis of geological background of mining face No.1122(1) in coal seam No.11-2,Zhangji Coal Mine,Huainan Mining Group Corporation.The mining-induced stress and cracks in overburden rocks are obtained by simulating an extraction in physical model.An evolution of mining-induced cracks in the process of advancing of coal mining face is characterized and three typical crack networks are taken from digital photos by means of image analysis.Moreover,the numerical software named COMSOL Multiphysics is employed to simulate the process of gas flow in three representative crack networks.Isograms of gas pressure at various times in mining-induced crack networks are plotted,suggesting a shape and dimension of gas accumulation area. | Zhou Hongwei Liu Jinfeng Xue Dongjie Yi Haiyang Xue Junhua | 2012 | International Journal of Mining Science and Technology2012，22，6： | 14 |
| 4 | Endothelial-specific m^6A modulates mouse hematopoietic stem and progenitor cell development via Notch signaling显示文摘 | Junhua Tv Yifan Zhang Suwei Gao Chunxia Zhang Yusheng Chen Wei Li Yun-Gui Yang Qi Zhou Feng Liu | 2018 | Cell Research2018，28，2： | 12 |
| 5 | Nitrogen 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 | 2014 | Chinese Geographical Science2014，24，2： | 10 |
| 6 | Dynamic assessment method of air target threat based on improved GIFSS显示文摘As the air combat environment becomes more complicated and changeable, accurate threat assessment of air target has a significant impact on air defense operations. This paper proposes an improved generalized intuitionistic fuzzy soft set (GIFSS) method for dynamic assessment of air target threat. Firstly, the threat assessment index is reasonably determined by analyzing the typical characteristics of air targets. Secondly, after the GIFSS at different time is obtained, the index weight is determined by the intuitionistic fuzzy set entropy and the relative entropy theory. Then, the inverse Poisson distribution method is used to determine the weight of time series, and then the time-weighted GIFSS is obtained. Finally, threat assessment of five air targets is carried out by using the improved GIFSS (I-GIFSS) and comparison methods. The validity and superiority of the proposed method are verified by calculation and comparison. | FENG Jinfu ZHANG Qiang HU Junhua LIU An | 2019 | Journal of Systems Engineering and Electronics2019，30，3： | 9 |
| 7 | Effects of rare earth modifying inclusions on the pitting corrosion of 13Cr4Ni martensitic stainless steel显示文摘In this study,the pitting corrosion behavior of 13Cr4Ni martensitic stainless steel(BASE)and that modified with rare earth(REM)in 0.1 mol/L Na Cl solution were characterized.Techniques such as automatic secondary electron microscope(ASPEX PSEM detector),scanning electron microscope(SEM),transmission electron microscope(TEM),scanning Kelvin probe force microscope(SKP),potentiodynamic and potentiostatic polarizations were employed.The results obtained indicate that BASE steel contains Al_(2)O_(3)/Mn S,Al_(2)O_(3) and Mn S inclusions,while REM steels contain(La,Ce,Cr,Fe)-O and(La,Ce,Cr,Fe)-O-S inclusions.Compared with BASE steel,REM steel is more susceptible to induce the metastable pitting nucleation and repassivation,whereas it restrains the transition from metastable pitting to stable pitting.Adding 0.021%rare earth element to BASE steel can reduce the number and area of inclusions,while that of 0.058%can increase the number and enlarged the size of inclusions,which is also the reason that pitting corrosion resistance of 58 REM steel is slightly lower than that of 21 REM steel.In the process of pitting corrosion induced by Al_(2)O_(3)/Mn S inclusions,Mn S is preferentially anodic dissolved,and also the matrix contacted with Al_(2)O_(3) is subsequently anodic dissolved.For REM steels,anodic dissolution preferentially occurs at the boundary between inclusions and matrix,while(La,Ce,Cr,Fe)-O inclusions chemically dissolve in local acidic environment or are separated from steel matrix.The chemically dissolved substance(La^(3+) and Ce^(3+))of(La,Ce,Cr,Fe)-O inclusions are concentrated in pitting pits,which inhibits its continuous growth. | Changgang Wang Rongyao Ma Yangtao Zhou Yang Liu Enobong Felix Daniel Xiaofang Li Pei Wang Junhua Dong Wei Ke | 2021 | Journal of Materials Science & Technology2021，，34： | 8 |
| 8 | Clinical 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 | 2018 | Journal of Traditional Chinese Medicine2018，38，4： | 7 |
| 9 | Design and Experimental Research on Seedling Pick-Up Mechanism of Planetary Gear Train with Combined Non-circular Gear Transmission显示文摘Currently, transplanting mechanisms for dryland plug seedlings in China are mainly semiautomatic and have low efficiency. The rotary seedling pick-up mechanism with a planetary gear train for non-uniform intermittent transmission, and a concave and convex locking arc device, has a large rigid impact. To solve these problems, according to the design requirements for a dryland plug seedling transplanting mechanism, a rotary seedling pick-up mechanism of a planetary gear train with combined non-circular gear transmission of incomplete eccentric circular and noncircular gears was proposed. This has the characteristics of two-times greater fluctuation of the transmission ratio in a cycle, and can achieve a non-uniform continuous drive. Through analysis of the working principle of the seedling pick-up mechanism, its kinematics model was established. The human–computer interaction optimization method and self-developed computer-aided analysis and optimization software were used to obtain a set of parameters that satisfy the operation requirements of the seedling pick-up mechanism. According to the optimized parameters, the structure of the seedling pick-up mechanism was designed, a virtual prototype of the mechanism was created, and a physical prototype was manufactured. A virtual motion simulation of the mechanism was performed, high-speed photographic kinematics tests were conducted, and the kinematic properties of the physical prototype were investigated, whereby the correctness of the theoretical model and the optimized design of the mechanism were verified. Further, laboratory seedling pick-up tests were conducted. The success ratio of seedling pick-up was 93.8% when the seedling pick-up efficiency of the mechanism was 60 plants per minute per row, indicating that the mechanism has a high efficiency and success ratio for seedling pick-up and can be applied to a dryland plug seedling transplanter. | Yaxin Yu Jikun Liu Bingliang Ye Gaohong Yu Xuejun Jin Liang Sun Junhua Tong | 2019 | Chinese Journal of Mechanical Engineering2019，32，3： | 7 |
| 10 | Effect of tin addition on corrosion behavior of a low-alloy steel in simulated costal-industrial atmosphere显示文摘The effect of tin addition on the atmospheric corrosion behavior of a low-alloy steel in sim ulated coastalindustrial atm osphere has been investigated by indoor wet/dry cyclic corrosion test (CCT). The results indicate that tin addition can obviously make the steel substrate more resistant to atmospheric corrosion by suppressing the cathodic H^+ reduction reaction, and but tin addition is not of obvious beneficial effect when the steel is covered with a thicker rust layer during long-term corrosion process. The reason lies in the fact that the presence of un-reduced H^+ can lower the electrolyte pH value and lead to a loose and porous rust layer on tin-containing steel sample than that on tin-free steel sample. In addition, the 120 CCT cycles corrosion process of the two steels can be divided into three stages. Both the tin-free and tin-containing steels show an increasing corrosion rate during the initial corrosion stage and then exhibit a decreasing corrosion rate during the second and third corrosion stages. Moreover, tin addition makes the tin-containing steel rust layer have a higher amount of α-FeOOH and lower am ount of γ-FeOOH and Fe3O4 than the tin-free steel rust layer. | Bo Liu Xin Mu Ying Yang Long Hao Xueyong Ding Junhua Dong Zhe Zhang Huaxing Hou Wei Ke | 2019 | Journal of Materials Science & Technology2019，35，7： | 6 |
| 11 | Adsorptive hemofiltration for sepsis management: expert recommendations based on the Asia Pacific experience显示文摘To the Editor:In sepsis,bacterial endotoxins play a central role by inducing a dysregulated and exaggerated release of inflammatory mediators and cytokines,often described as the“cytokine storm”or“cytokinemia.”[1]Both endotoxins and cytokines have been implicated in the development of organ dysfunction,including acute kidney injury(AKI).[2]Removing circulating endotoxins and excess cytokines from the circulation restores chemotactic gradients,localizing the immune response to the principal site of infection and re-establishing a regulated immune response.[1,3]Therefore,using hemofilters with enhanced endotoxin and cytokine adsorptive properties may bring about additional therapeutic benefits compared with conventional continuous renal replacement therapy(CRRT)filters. | Ling Zhang Matthew Cove Binh G.Nguyen Nuttha Lumlertgul Kartik Ganesh Alfred Chan Giang T.H.Bui Chunwen Guo Junhua Li Songqiao Liu Mian Peng Kit W.Foong Jian Zhang Minmin Wang Jacques Goldstein Kai Harenski | 2021 | Chinese Medical Journal2021，，18： | 6 |
| 12 | Global Calibration Method of Multi-sensor Vision System Using Skew Laser Lines显示文摘Multi-sensor vision system plays an important role in the 3D measurement of large objects.However,due to the widely distribution of sensors,the problem of lacking common fields of view(FOV) arises frequently,which makes the global calibration of the vision system quite difficult.The primary existing solution relies on large-scale surveying equipments,which is ponderous and inconvenient for field calibrations.In this paper,a global calibration method of multi-sensor vision system is proposed and investigated.The proposed method utilizes pairs of skew laser lines,which are generated by a group of laser pointers,as the calibration objects.Each pair of skew laser lines provides a unique coordinate system in space which can be reconstructed in certain vision sensor's coordinates by using a planar pattern.Then the geometries of sensors are computed under rigid transformation constrains by taking coordinates of each skew lines pair as the intermediary.The method is applied on both visual cameras with synthetic data and a real two-camera vision system;results show the validity and good performance.The prime contribution of this paper is taking skew laser lines as the global calibration objects,which makes the method simple and flexible.The method need no expensive equipments and can be used in large-scale calibration. | LIU Qianzhe SUN Junhua LIU Zhen ZHANG Guangjun | 2012 | Chinese Journal of Mechanical Engineering2012，25，2： | 6 |
| 13 | Implementing single-scale wavelet transform processor with magnetostatic surface wave device显示文摘When the envelope of the conducting strips for the input transducer of magnetostatic surface wave(MSSW) device is designed according to the wavelet-function envelope,the impulse-response function of the input transducer for MSSW device is equal to the wavelet function,so that single-scale wavelet-transform processor of MSSW type is fabricated.First,according to the envelope function of the wavelet,the length function of the conducting strips is defined,then,the lengths of the conducting strips can be calculated from the length function of the conducting strips,finally,the input transducer can be designed according to the lengths and widths for the conducting strips.The compensation method of the insertion loss for single-scale wavelet trans-form processor of MSSW type is also given in the paper.When the output end of single-scale wavelet transform processor of MSSW type is connected to the amplifier,its insertion loss can be compensated. | LU WenKe ZHU ChangChun KUANG Lun ZHANG Ting LIU JunHua | 2011 | Science China(Technological Sciences)2011，54，6： | 6 |
| 14 | Electroacupuncture Alleviates Motor Symptoms and Up-Regulates Vesicular Glutamatergic Transporter 1 Expression in the Subthalamic Nucleus in a Unilateral 6-Hydroxydopamine-Lesioned Hemi-Parkinsonian Rat Model显示文摘Previous studies have shown that electroacupuncture(EA) promotes recovery of motor function in Parkinson's disease(PD). However the mechanisms are not completely understood. Clinically, the subthalamic nucleus(STN) is a critical target for deep brain stimulation treatment of PD, and vesicular glutamate transporter 1(VGlu T1) plays an important role in the modulation of glutamate in the STN derived from the cortex. In this study,a 6-hydroxydopamine(6-OHDA)-lesioned rat model of PD was treated with 100 Hz EA for 4 weeks. Immunohistochemical analysis of tyrosine hydroxylase(TH) showed that EA treatment had no effect on TH expression in the ipsilateral striatum or substantia nigra pars compacta,though it alleviated several of the parkinsonian motor symptoms. Compared with the hemi-parkinsonian rats without EA treatment, the 100 Hz EA treatment significantly decreased apomorphine-induced rotation and increased the latency in the Rotarod test. Notably, the EA treatment reversed the 6-OHDA-induced down-regulation of VGlu T1 in the STN. The results demonstrated that EA alleviated motor symptoms and up-regulated VGlu T1 in the ipsilateral STN of hemi-parkinsonian rats, suggesting that up-regulation of VGlu T1 in the STN may be related to the effects of EA on parkinsonian motor symptoms via restoration of function in the cortico-STN pathway. | Yanyan Wang Yong Wang Junhua Liu Xiaomin Wang | 2018 | Neuroscience Bulletin2018，34，3： | 5 |
| 15 | Beam Measurement System in NSRL显示文摘This paper describes the beam measurement system for the accelerator of the National Synchrotron Radiation Laboratory (NSRL). The design considerations of the beam measurement instrumentation system for the NSRL are aided by the commissioning of the machine and provide sufficient machine parameters for machine study as well as the common operation. The beam measurement system includes the part for the linac and transport line and the part for the storage ring. The measurement results are presented in the paper. | Sun, Baogen Lu, Ping Wang, Junhua Fang, Zhigao Liu, Jianhong | 2000 | Journal of Systems Engineering and Electronics2000，11，3： | 4 |
| 16 | Morphological adaptation of sheep's rumen epithelium to high-grain diet entails alteration in the expression of genes involved in cell cycle regulation, cell proliferation and apoptosis显示文摘Background: The objectives of this study were to characterize changes in the relative m RNA expression of candidate genes and proteins involved in cell cycle regulation, cell proliferation and apoptosis in the ruminal epithelium(RE) of sheep during high-grain(HG) diet adaptation.Results: Twenty sheep were assigned to four groups with five animals each. These animals were assigned to different periods of HG diet(containing 40% forage and 60% concentrate mix) feeding. The HG groups received an HG diet for7(G7, n = 5), 14(G14, n = 5) and 28 d(G28, n = 5), respectively. In contrast, the control group(CON, n = 5) was fed the forage-based diet for 28 d. The results showed that HG feeding linearly decreased(P < 0.001) the ruminal p H, and increased the concentrations of ruminal total volatile fatty acid(linear, P = 0.001), butyrate(linear, P < 0.001), valerate(quadratic P = 0.029) and the level of IGF-1(quadratic, P = 0.043) in plasma. The length(quadratic, P = 0.004), width(cubic, P = 0.015) and surface of the ruminal papillae(linear, P = 0.003) were all enlarged after 14 d of HG diet feeding.HG feeding cubically increased the number of cell layers forming the stratum corneum(SC, P < 0.001) and the thickness of the SC(P < 0.001) and stratum basale(P < 0.001). The proportion of basal layer cells in the RE decreased(linear, P < 0.001) in the G0/G1-phase, but it increased linearly(P = 0.006) in the S-phase and cubically(P = 0.004) in the G2/M-phases. The proportion of apoptosis cells in G7, G14 and G28 was reduced compared to the CON(quadratic, P <0.001). HG diet feeding linearly decreased the m RNA expression of Cyclin E1(P = 0.021) and CDK-2(P = 0.001) and(P = 0.027) the protein expression of Cyclin E1. Feeding an HG diet linearly increased the m RNA expression of genes IGFBP-2(P = 0.034) and IGFBP 5(P < 0.009), while linearly decreasing(P < 0.001) the IGFBP 3 expression. The expression of cell apoptosis gene Caspase 8 decreased(quadratic, P = 0.012), while Bad m RNA expression tended to decrease(cubic, P = 0.053) after HG feeding.Conclusions: These results demonstrated sequential changes in rumen papillae size, cell cycle regulation and the genes involved in proliferation and apoptosis as time elapsed in feeding a high-grain diet to sheep. | Lei Xu Yue Wang Junhua Liu Weiyun Zhu Shengyong Mao | 2018 | Journal of Animal Science and Biotechnology2018，9，3： | 4 |
| 17 | Research on dynamic characteristics of multi-sensor system in the case of cross-sensitivity显示文摘In this study, the dynamic characteristic of a multi-sensor system made up of such sensors as are sensitive to several parameters is discussed, and the effect of cross-sensitivity on the precision of a measurement system is also discussed. A multi-sensor system is looked as a serial of a linear filter and a memoryless nonlinear system, i.e. Wiener system, and the subsequent information fusion system is regarded as a Hammerstein system, i.e. a serial of a memoryless nonlinear system and a linear filter. On the basis of static calibration, it is presented to determine the inverse filter in a Hammerstein system using blind deconvolution. In order to control the uncertainty of amplitude of signals recovered by blind deconvolution well, a regulation approach to regulating the inverse linear filter coefficient matrixes is presented according to the identity between inverse filter coefficient matrixes and static calibrating matrix. So the approximate inverse dynamic model of multi-sensor system is obtained, the degree of distortion of dynamic measurement result is reduced, the measurement precision is improved, and the need of practice can be reached. Simulation example and simulation result show that the recovered error of the inputs of sensor system, the frequency of which is 1/10 of sampling frequency, is 1/20 of the measurement results without dynamic compensation, and is one half of the measurement results with sole dynamic compensation, and the rapidity is improved 2 times. The dynamic compensation results of a metal oxide semiconductor methane sensor show that the dynamic measurement error is less than one half of that without dynamic compensation. So this method expands the bandwidth of multi-sensor system. | TANG Xiaojun LIU Junhua | 2005 | Science China(Technological Sciences)2005，48，1： | 4 |
| 18 | Effects 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 | 2016 | Journal of Plant Ecology2016，9，1： | 4 |
| 19 | Analysis and Identification of Chemical Constituents of Fenugreek by UPLC-IT-MSn and UPLC-Q-TOF-MS显示文摘 | WANG Jiaqi JIANG Wenyue LIU Zhongying WANG Junhua FU Tianyue WANG Yongsheng | 2017 | Chemical Research in Chinese Universities2017，33，5： | 4 |
| 20 | Study on the Coincident-Loop Transient Electromagnetic Method in Seafloor Exploration——Taking Jiaodong Polymetallic Mine as a Model显示文摘The transient electromagnetic(TEM)method becomes more urgent than ever for marine ex-ploration due to abundant resource reserves and the increasing undersea engineering construction activities,especially in the offshore exploration of mineral deposits such as Sanshandao gold mine.However,the re-search and application of TEM method in marine environment are still challenged by many problems.Such contradiction motivates our study on the coincident-loop TEM in seafloor exploration.The TEM response of coincident loops is firstly derived in the integral form,based on the potential functions in Helmholtz equ-ations for a magnetic source locating in the whole-space layered model.The frequency-domain vertical magnetic field is described as the Hankel integral with double first-order Bessel functions of first kind.Se-condly,the time-domain induced voltage is obtained by transforming the frequency-domain response through the cosine transform and then taking the derivative of time.To simultaneously solve the Hankel transform and the cosine transform,a novel algorithm is introduced by adapting the fixed-point quadra-ture and extrapolation via the Shanks transformation.Finally,a typical conductivity model for marine po-lymetallic deposit is designed to investigate the characteristic of TEM response under various conditions.Numerical results demonstrate that existence of conductive seawater causes the TEM response to increase significantly and decay slower.The air-sea reflected electromagnetic waves lead to a significantly large fake negative response(NR)in shallower seawater with depth less than 300 m.Increase in the height of loops will weaken and delay the anomaly response and shorten the observation time-window.The height of configu-ration should be no more than 100 m for shallower targets and 50 m for deeper targets,respectively.The observation time-window should cover 10-1000 ms.Increase in the radius of loops only enhances the TEM response proportionally but hardly improves the relative anomaly.The vertical resolution on the low-resistivity target approximates 20 m for the configuration considered in the study.Decreases in D.C.resistivity and chargeability cause the positive response(PR)to increase significantly and decay more ra-pidly.Meanwhile,the NR is advanced and enlarged significantly and decays slower compared with the PR.The influence of time constant is not monotony and there exists an optimal value for producing the maxi-mum NR.As the frequency parameter increases,the PR is caused to decay more rapidly without magni-tude change and the NR is advanced and decays more rapidly with significant increase in magnitude.The influence of frequency parameter is more pronounced than that of time constant. | Yixing Ma Junhua Hu Yanjun Chang Zujian Liu | 2021 | Journal of Earth Science2021，32，1： | 3 |
您所在的机构暂未开通此部分的功能，请联系管理员