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1The discovery of Palaeoproterozoic volcanic rocks in the Bulunkuoler Group from the Tianshuihai Massif in Xinjiang of Northwest China and its geological significance显示文摘In the Dabudaer region of the Tianshuihai Massif (Xinjiang, Northwest China), metavolcanic rocks within the mainly meta-sedimentary Bulunkuoler Group are basalt, basaltic andesite, and rhyolite. In situ zircon U-Pb LA-ICP-MS dating on rhyolite magmatic zircons yielded an age of 2481±14 Ma, interpreted as the eruption age of the Bulunkuoler Group volcanic rocks. The basalt and basaltic andesite are low-Al tholeiite series and the rhyolite is low-Al calc-alkaline series. All of rocks are charac-terized by enrichment of LREE and LILE (Rb, Th and Ba), depletion of P, Nb, Ta and Ti, and absence of Eu anomalies. The εNd(t) of basalts ranges from 3.14 to 4.88 indicating a depleted mantle source. The trace element signatures show that these magmas experienced intense crustal contamination during their ascent. Direct evidence for crustal contamination is the xenocrystic zircons in the ryholite, with ages back to ca. 3300 Ma. The primitive-mantle normalized and Zr/Y-Zr diagrams for the basic volcanic rocks show that they formed in an intra-continental tectonic setting. Combined with the previous studies and compared with North China Craton Neoarchean basic volcanic rocks, it is supposed that the Bulunkuoler Group volcanic rocks reflect the Palaeoproterozoic mantle magma underplating and interaction with felsic crust.JI WenHua LI RongShe CHEN ShouJian HE ShiPing ZHAO ZhenMing BIAN XiaoWei ZHU HaiPing CUI JiGang REN JuanGang 2011Science China Earth Sciences2011,54,1:22
2Accelerated Degradation Reliability Modeling and Test Data Statistical Analysis of Aerospace Electrical Connector显示文摘As few or no failures occur during accelerated life test,it is difficult to assess reliability for long-life products with traditional life tests.Reliability assessment using degradation data of product performance over time becomes a significant approach.Aerospace electrical connector is researched in this paper.Through the analysis of failure mechanism,the performance degradation law is obtained and the statistical model for degradation failure is set up;according to the research on statistical analysis methods for degradation data,accelerated life test theory and method for aerospace electrical connector based on performance degradation is proposed by improving time series analysis method,and the storage reliability is assessed for Y11X series of aerospace electrical connector with degradation data from accelerated degradation test.The result obtained is basically consistent with that obtained from accelerated life test based on failure data,and the two estimates of product's characteristic life only have a difference of 8.7%,but the test time shortens about a half.As a result,a systemic approach is proposed for reliability assessment of highly reliable and long-life aerospace product.CHEN Wenhua LIU Juan GAO Liang PAN Jun ZHOU Shengjun 2011Chinese Journal of Mechanical Engineering2011,24,6:22
3Changes of protein oxidation,lipid oxidation and lipolysis in Chinese dry sausage with different sodium chloride curing salt content显示文摘The effect of sodium chloride(NaCl)curing salt content on protein oxidation,lipid oxidation and lipolysis of Chinese dry sausage was investigated.Two groups Chinese dry sausages with 2%and 4%(m/m)salt content were studied.The degree of protein oxidation increased during the processes in two groups sausages,while the content of phospholipids decreased,neutral lipids and free fatty acids increased.The degree of protein oxidation,lipid oxidation and lipolysis in 4%NaCl content group was higher than those in 2%NaCl content group,while 4%NaCl content group has higher lipase activity.In conclusion,4%NaCl may facilitate the protein oxidation,lipid hydrolysis and oxidation in Chinese dry sausage,and the protein oxidation had strong correlation with lipid oxidation and lipolysis.The results could provide a basis for improving the technology of industrial production.Bing Zhao Huimin Zhou Shunliang Zhang Xiaoqian Pan Su Li Ning Zhu Qianrong Wu Shouwei Wang Xiaoling Qiao Wenhua Chen 2020Food Science and Human Wellness2020,9,4:22
4Time-dependent categorization of volatile aroma compound formation in stewed Chinese spicy beef using electron nose profile coupled with thermal desorption GC–MS detection显示文摘In the present study,flavor profiles of Chinese spiced beef in the cooking process were comparatively analyzed by electronic nose,gas chromatography–mass spectrometry(GC–MS)with a thermal desorption system(TDS),and solid-phase microextraction(SPME).A total of 82 volatile compounds were identified,and 3-methyl-butanal,pentanal,hexanal,-xylene,heptanal,limonene,terpinene,octanal,linalool,4-terpinenol,-terpineol,and(E)-anethole were identified as the characteristic flavor compounds in Chinese spiced beef.Variation in the content of volatile components produced by different cooking processes was observed.In general,a cooking time of 4 h resulted in optimal flavor quality and stability.Results indicated that the electronic nose could profile and rapidly distinguish variation among different cooking time.The volatile profiling by TDS-GC–MS and responses from the electronic nose,in combination with multivariate statistical analysis,are a promising tool for control the cooking process of spiced beef.Hui Gong Zhen Yang Meng Liu Zhijia Shi Jiapeng Li Wenhua Chen Xiaoling Qiao 2017Food Science and Human Wellness2017,6,3:21
5A step metallogenetic model for gold deposits in the northwestern Shandong Peninsula, China显示文摘Based on our study of the nature and variation of mineralization-controlling faults in their deep extension and the spatial distribution of gold orebodies in the northwestern Shandong Peninsula (NSP), here we propose that the gold deposits in the Jiaojia gold belt are controlled by listric faults and the gold deposits in the NSP are controlled by extensional fault system. We also suggest that there is a multiple mineralization space in the deep part of the NSP gold belt. As steps or benches occur along the deep extention of the listric fault where its dipping angle changes from steep to gentle, a number of gold deposits are correspondingly distributed as a steplike pattern, which is named as a step metallogenetic model for gold deposits in the NSP. The gold deposits in Shandong Peninsula were formed in the Cretaceous when the crust in the region experienced extention and thinning following the strong collision between North China Plate and Yangtze Plate during the Triassic. Crust anataxis, fluid remobilization, and extention-detachement of the crust are the leading factors for the gold mineralization.SONG MingChun YI PiHou XU JunXiang CUI ShuXue SHEN Kun JIANG HongLi YUAN WenHua WANG HuaJiang 2012Science China Earth Sciences2012,55,6:21
6Optimization of heat transfer and heat-work conversion based on generalized heat transfer law显示文摘Examples of heat transfer and heat-work conversion are optimized with entropy generation and entransy loss,respectively based on the generalized heat transfer law in this paper.The applicability of entropy generation and entransy loss evaluation in these optimization problems is analyzed and discussed.The results show that the entransy loss rate reduces to the entransy dissipation rate in heat transfer processes,and that the entransy loss evaluation is effective for heat transfer optimization.However,the maximum heat transfer rate does not correspond to the minimum entropy generation rate with prescribed heat transfer temperature difference,which indicates that the entropy generation minimization is not always appropriate to heat transfer optimization.For heat-work conversion processes,the maximum entransy loss rate and the minimum entropy generation rate both correspond to the maximum output power,and they are both appropriate to the optimization of the heat-work conversion processes discussed in this paper.CHENG XueTao WANG WenHua LIANG XinGang 2012Science China(Technological Sciences)2012,55,10:19
7Forest Ecosystem Services and Their Values in Beijing显示文摘As the most important ecosystem in Beijing, the forest supports a lot of ecosystem services to local and around communities, which plays a key role in the maintenance of urban ecological security.However, the valuation on the forest ecosystem services based on regional scale could not provide precise and reasonable values for forestry sector management.In this study, we estimated the magnitudes and economic values of the forest ecosystem services in Beijing at sublot level.The economic value of forest ecosystem services in Beijing was estimated to be 19 339.71×10 6 yuan(RMB) in 2004.Among all the ecosystem services indicators we estimated in this study, only fruit, timber and part of the recreation(which only include the tourism income from the forest parks and scenic areas, but not include that from other forest types) were measured in the social economic system.As estimated in this study, more than 82.19% of the economic value of forest ecosystem services could not be measured in the socio-economic statistical system.The importance of forest ecosystem services in Beijing to human welfare was underestimated by the socio-economic system.Therefore, the policies about the eco-compensation of forest ecosystem services should be established to maintain the sustainable supply of the forest ecosystem services in Beijing.XIE Gaodi LI Wenhua XIAO Yu ZHANG Biao LU Chunxia AN Kai WANG Jixing XU Kang WANG Jinzeng 2010Chinese Geographical Science2010,20,1:18
8Adsorption behavior of phosphate on Lanthanum(Ⅲ) doped mesoporous silicates material显示文摘A series of lanthanum doped meosoporous MCM-41(LaxM41,x is Si/La molar ratio) was prepared by sol-gel method.The surface structure of the materials was investigated with X-ray diffraction and N2 adsorption/desorption technique.The content of La in the materials was determined by ICP.It was found that the La content of La25M41,La50M41 and La100M41 was 7.53%,3.89% and 2.32%,respectively.The phosphate adsorption capacities increased with increasing amount of La incorporation.With 0.40 g La25M41 99.7% phosphate could be removed.The effects of Si/La molar ratio,LaxM41 dose,pH,initial concentration of phosphate solution,co-ions on phosphate adsorption were also evaluated.The phosphate adsorption kinetics of LaxM41 could be well-described by the pseudo second-order model,and Langmuir isotherm fit equilibrium data much better than the Freundlich isotherm.Jianda Zhang Zhemin Shen Wenpo Shan Ziyan Chen Zhijian Mei Yangming Lei Wenhua Wang 2010Journal of Environmental Sciences2010,22,4:18
9Mesozoic-Cenozoic Multi-Stage Intraplate Deformation Events in the Langshan Region and their Tectonic Implications显示文摘In the Langshan region, northwestern China, marked multi-stage intraplate deformation events have occurred since the Mesozoic, including(1) northeast-striking ductile left-lateral strike slip during the Middle-Late Triassic, which is closely related to the collision between the North China and the Yangtze plates;(2) top-to-the-southeast thrust with northwest-southeast trending maximum compression during the Late Jurassic;(3) nearly eastward detachment during the Early Cretaceous;(4) top-to-the-northwest thrust with northwest-southeast trending maximum compression during the Late Cretaceous and Early Cenozoic;(5) northeast-striking brittle left-lateral strike slip with nearly north-south trending maximum compression; and(6) northwest-southeast extension during the Middle-Late Cenozoic. All these deformation events belong to the intraplate deformation across the entire Central Asian region and respond to the tectonic events along the plate boundaries or deep tectonics. The structures developed in early events in the crust were the most important factors controlling the later deformation styles, and few new structures have later developed. Based on previous research and our results, the paleostress inversion in the Langshan region shows that the Mesozoic intraplate deformations in the study region mainly resulted from the tectonic events from the Paleo-Pacific region and have no or a weak relation to the Tethys region. During the Late Jurassic, the maximum compression from the Mongolia-Okhotsk region cannot be excluded. The Langshan region is the bridge between southern Mongolia and the western Ordos tectonic belt and is thus important to understand the nature and relationship between both regions.ZHANG Jin LI Jinyi LI Yanfeng QI Wenhua ZHANG Yiping 2014Acta Geologica Sinica(English Edition)2014,88,1:18
10Adaptive fuzzy tracking control for a class of uncertain MIMO nonlinear systems using disturbance observer显示文摘In this paper,the adaptive fuzzy tracking control is proposed for a class of multi-input and multioutput(MIMO)nonlinear systems in the presence of system uncertainties,unknown non-symmetric input saturation and external disturbances.Fuzzy logic systems(FLS)are used to approximate the system uncertainty of MIMO nonlinear systems.Then,the compound disturbance containing the approximation error and the timevarying external disturbance that cannot be directly measured are estimated via a disturbance observer.By appropriately choosing the gain matrix,the disturbance observer can approximate the compound disturbance well and the estimate error converges to a compact set.This control strategy is further extended to develop adaptive fuzzy tracking control for MIMO nonlinear systems by coping with practical issues in engineering applications,in particular unknown non-symmetric input saturation and control singularity.Within this setting,the disturbance observer technique is combined with the FLS approximation technique to compensate for the efects of unknown input saturation and control singularity.Lyapunov approach based analysis shows that semi-global uniform boundedness of the closed-loop signals is guaranteed under the proposed tracking control techniques.Numerical simulation results are presented to illustrate the efectiveness of the proposed tracking control schemes.CHEN Mou CHEN WenHua WU QinXian 2014Science China(Information Sciences)2014,57,1:17
11Entransy analysis of open thermodynamic systems显示文摘The concept of entransy developed in recent years can describe the heat transport ability.This paper extends this concept to the open thermodynamic system and defines the concept of enthalpy entransy.The entransy balance equation of steady open thermodynamic systems,as well as the concept of entransy loss,is developed.The entransy balance equation is applied to analyzing and discussing the air standard cycle.It is found that the entransy loss rate can describe the change in net power output from the cycle but the entropy generation rate cannot when the heat absorbed by the working medium is from the combustion reaction of the gas fuel.When the working medium is heated by a high temperature stream,both the maximum entransy loss rate and the minimum entropy generation rate correspond to the maximum net power output from the cycle.Hence,the concept of entransy loss is an appropriate figure of merit that describes the cycle performance.CHENG XueTao WANG WenHua LIANG XinGang 2012Chinese Science Bulletin2012,57,22:16
12Effect of tannic acid on corrosion behavior of carbon steel in NaCl solution显示文摘Corrosion behavior of unrusted Q235 carbon steel was investigated in 3.5% NaCl solutions with 1–5 wt%tannic acid addition, using electrochemical methods including electrochemical impedance spectra(EIS),potentiodynamic polarization and scanning vibrating electrode technique(SVET) combined with surface analysis. Results show that the corrosion rate decreases with increasing tannic acid concentration. As compared with tannic acid-free solution, 1% tannic acid does not provide inhibition effect during the whole immersion, while inhibition effect is observed for 3% tannic acid after 8 h and for 5% tannic acid after 4 h. The inhibition efficiency by weight loss measurements(áw) for 1%, 3%, and 5% tannic is around-17.2%, 40.3%, and 51.5%, respectively. Corrosion of unrusted carbon steel in the presence of tannic acid is attributed to the joint effect of tannic acid adsorption and pH decrease. Formation of ferric-tannates is verified by X-ray photoelectron spectroscopy(XPS) and Raman spectra. The reaction mechanism between tannic acid and unrusted carbon steel is proposed.Wenhua Xu En-Hou Han Zhenyu Wang 2019Journal of Materials Science & Technology2019,35,1:16
13Environment-ecosystem dynamic processes of Spartina alterniflora salt-marshes along the eastern China coastlines显示文摘Spartina alterniflora is ecologically important in its original habitat; however, it has caused controversy since it was introduction into China(now it has been spreading rapidly on the Jiangsu, Shanghai, Zhejiang and Fujian coasts). The purpose of the present contribution is, on the basis of an analysis and synthesis of existing data sets, to evaluate the environmental-ecological effects of S. alterniflora, and to identify the relevant scientific problems that require further research in the future. Investigations have shown that, by reducing the near-bed shear stress associated with tidal currents, S. alterniflora can enhance the settling flux of suspended sediment and deposition rate on the tidal flats over the region. Further, field survey and analysis indicate that the S. alterniflora salt-marsh has a high primary production and provides a new type of habitat for the native benthic fauna. Some macro-, meio- and micro-fauna that used to live in the native salt-marshes have adapted to the S. alterniflora salt-marsh, forming a new ecosystem. Under the influences of a number of background factors, such as latitude variations and the coastal type, the environmental-ecological changes induced by Spartine have regional differentiations. To the north of Hangzhou Bay, with a high position of the pre-Holocene stratum base, a large width of the tidal flats, and a gentle bed slope, only a small part of the intertidal zone is occupied by the S. alterniflora salt-marsh. Here, the S. alterniflora salt-marshes mainly play a positive role in coastal protection and ecosystem functioning. In contrary, to the South of Hangzhou Bay, The pre-Holocene deposits are situated in relatively deeo waters, and the width of the tidal flats formed within coastal embayments is relatively narrow. As such, the expansion of S. alterniflora has squeezed the living space of other intertidal organisms, thus has a negative ecological effect. Therefore, the regional differentiation of the Spartina effects should be sufficiently considered in coastal development and management. Furthermore, in order to predict the future evolution of the S. alterniflora wetlands over the region, in addition to in situ monitoring and measurements, an ecosystem dynamic model should be established, taking into account the coupling of the rerrestrial and marine environmental-ecological processes.GAO Shu DU YongFen XIE WenJing GAO WenHua WANG DanDan WU XiaoDong 2014Science China Earth Sciences2014,57,11:15
14Modeling and power performance improvement of a piezoelectric energy harvester for low-frequency vibration environment显示文摘A novel oscillator structure, bimorph piezoelectric cantilever beam with two-stepped variable thicknesses,is proposed to improve the energy harvestingperformance of the vibration energy harvester (VEH) under low-frequency vibration environment. Firstly, the piezoelectric cantilever is segmented to obtain the energy functions based on the Euler-Bernoulli beam assumptions, and the Galerkin approach is utilized to discretize the energy functions. Applying boundary conditions and continuity conditions enforced at separation locations, the electromechanical coupled governing equations for the piezoelectric energy harvesterareintroduced by means of the Lagrange equations. Furthermore, the steady state response expressions are obtained for harmonic base excitations at arbitrary frequencies. Numerical results are computed and the effects ofthe lengths-ratio, thicknesses-ratio,end thicknessand load resistance on the output voltage, harvested power and power density are discussed. Moreover, to verify thecorrectness ofanalytical results, the finite element method (FEM)simulationis also conducted to analyze performance of the proposed VEH, where a good agreement is presented. All the results show thatthe present oscillator structureis moreefficient than the conventional uniform beam structure, specifically, for vibration energy harvesting in low-frequency environment.Dongxing Cao Yanhui Gao Wenhua Hu 2019Acta Mechanica Sinica2019,35,4:15
15Evaluating Beijing’s human carrying capacity from the perspective of water resource constraints显示文摘As the demands on limited water resources intensify, concerns are being raised about the human carrying capacity of these resources. However, few researchers have studied the carrying capacity of regional water resources. Beijing, the second-largest city in China, faces a critical water shortage that will limit the city’s future development. We developed a method to quantify the carrying capacity of Beijing’s water resources by considering water-use structures based on the proportions of water used for agricultural, industrial, and domestic purposes. We defined a reference structure as 45:22:33 (% of total, respectively), an optimized structure as 40:20:40, and an ideal structure as 50:15:35. We also considered four domestic water quotas: 55, 75, 95, and 115 m 3 /(person·yr). The urban carrying capacity of 10–12 million was closest to Beijing’s actual 2003 population for all three water-use structures with urban domestic water use of 75 m 3 /(person·yr). However, after accounting for our underlying assumptions, the adjusted carrying capacity is closer to 5–6 million. Thus, Beijing’s population in 2003 was almost twice the adjusted carrying capacity. Based on this result, we discussed the ecological and environmental problems created by Beijing’s excessive population and propose measures to mitigate these problems.Yingxuan Zhang Min Chen Wenhua Zhou Changwei Zhuang Zhiyun Ouyang 2010Journal of Environmental Sciences2010,22,8:14
16Step-stress Accelerated Degradation Test Modeling and Statistical Analysis Methods显示文摘In order to get a rapid assessment on the storage reliability of high-reliable and long-life products within the storage period,accelerated degradation test data with a large amount of reliability information of product is adopted.Conducting a constant-stress accelerated degradation test(CSADT)is generally very costly as it requires a large sample size and long time for test.To overcome this problem,it is necessary to carry out research on modeling and statistical analysis methods of step-stress accelerated degradation test(SSADT).Taking electrical connectors as the object,a research is conducted on statistical model and assessment method for SSADT.On the basis of mixed-effect degradation path model,the statistical model of SSADT for electrical connectors is presented,the maximum likelihood method for SSADT data based on mixed-effect degradation model is proposed.SSADT accelerated by temperature stress is conducted to Y11X-1419 type of electrical connectors,and the storage reliability is assessed with the SSADT data.Compared with the result obtained from accelerated life test,the reliability estimation of 32-year storage period for electrical connectors obtained from SSADT data only have a difference of 0.869%,which validates the accuracy of the degradation model and the feasibility of the test data statistic analysis method put forward.CHEN Wenhua LIU Juan GAO Liang PAN Jun LU Xianbiao 2013Chinese Journal of Mechanical Engineering2013,26,6:14
17Compound Zhebei granules combined with chemotherapy for the treatment of refractory acute leukemia: a randomized clinical trial显示文摘OBJECTIVE: To observe the effect of compound Zhebei granules(CZBG) with chemotherapy in the treatment of refractory acute leukemia.METHODS: In this multicenter, double-blind, placebo-controlled clinical trial, we used a central(online) randomization system to assign 235 patients to two treatment groups. A total of 118 patients received chemotherapy combined with CZBG(4 g,twice daily) and 117 patients received chemotherapy plus placebo. The clinical efficacy was evaluated at the end of one chemotherapeutic cycle.RESULTS: In the full analysis set, in which deaths due to disease progression were regarded as inefficacy, the rates of complete remission(CR) and partial remission(CR + PR) were 32.35% and 50.00%,respectively, for the chemotherapy combined with CZBG group, and 23.08% and 35.58%, respectively,for the chemotherapy plus placebo group. There was a statistically significant difference between the two groups according to a ysis set(PPχ2test(P < 0.05). In the per protocol analS), the CR(33.67%),CR+PR(52.04%) response rates for the chemotherapy plus CZBG group were significantly different from the response rates of the control group(CR:24.24% and CR+PR: 37.37%), respectively(P < 0.05).CONCLUSION: CZBG plus chemotherapy can improve the clinical remission rate of refractory acute leukemia after one just one therapeutic cycle.Hou Li Yang Shulian Yang Wenhua Zhou Yuhong Liu Feng Yang Hongyong Sun Weizheng Li Dongyun Xu Yamei Chen Xinyi 2016Journal of Traditional Chinese Medicine2016,36,5:13
18Extracellular Signal-Regulated Kinase in Nucleus Accumbens Mediates Propofol Self-Administration in Rats显示文摘Clinical and animal studies have indicated that propofol has potential for abuse,but the specific neurobiological mechanism underlying propofol reward is not fully understood.The purpose of this study was to investigate the role of extracellular signal-regulated kinase(ERK) signal transduction pathways in the nucleus accumbens(NAc) in propofol self-administration.We tested the expression of p-ERK in the NAc following the maintenance of propofol self-administration in rats.We also assessed the effect of administration of SCH23390,an antagonist of the D1 dopamine receptor,on the expression of p-ERK in the NAc in propofol self-administering rats,and examined the effects of intra-NAc injection of U0126,an MEK inhibitor,on propofol reinforcement in rats.The results showed that the expression of p-ERK in the NAc increased significantly in rats maintained on propofol,and pre-treatment with SCH23390 inhibited the propofol selfadministration and diminished the expression of p-ERK in the NAc.Moreover,intra-NAc injection of U0126(4 μg/side) attenuated the propofol self-administration.The data suggest that ERK signal transduction pathways coupled with D1 dopamine receptors in the NAc may be involved in the maintenance of propofol self-administration and its rewarding effects.Benfu Wang Xiaowei Yang Anna Sun Lanman Xu Sicong Wang Wenxuan Lin Miaojun Lai Huaqiang Zhu Wenhua Zhou Qingquan Lian 2016Neuroscience Bulletin2016,32,6:12
19Mineralogy,distribution,occurrence and removability of trace elements during the coal preparation of No.6 coal from Heidaigou mine显示文摘Optical microscopy and scanning electron microscopy in conjunction with energy dispersed X-ray spectrometry(SEM–EDX)were used to study the minerals and the concentrations of 33 trace elements in No.6 coal from Heidaigou mine.The distributions,organic affinity and removability of 18 trace elements were studied by float-sink experiments.A determination of the maceral groups was also undertaken.A high mineral content,dominated by kaolinite,was found in No.6 coal from Heidaigou mine.The bauxite content was relatively high and it was mainly present as individual particles in fusinite lumens or was intimately intergrown with carbonate minerals.The pyrite and quartz contents were low.Some marcasite with a parallel twin structure was observed by cross-polar reflected light.A small amount of bean-like goyazite was present in the calcite.The weighted trace element content in Heidaigou formations is relatively low,which is beneficial for coal processing and utilization.The concentrations of Ga,Hg,Pb,Se,Th,Ta are relatively high compared with the average values of Chinese coals.As,Hg,Mo,Ge,Ga,Ta,Ti,W,Mn are mainly present in minerals while B,Be,Th,P,Sc,Sr,V,Y,Yb are mainly found in organic matter.As,Ge,Hg,Mo are mainly present in sulfides and Be,Th,P,Sc,Sr,Y,Yb are mainly present in inertinite.B and V are mainly present in vitrinite.The high organic affinity and the low theoretical removability of most trace elements cause difficulties in removing them during coal preparation.Xiangfei Bai Yue Wang Wenhua Li 2014International Journal of Coal Science & Technology2014,1,4:12
20Potential influence of water level changes on energy flows in a lake food web显示文摘Large seasonal water-level fluctuations may influence isotopic signatures of primary producers and the types and amounts of these potential food sources accessible to aquatic fauna of Poyang Lake,the largest freshwater lake in China.In this study,the isotopic signatures of primary producers and consumers were determined,stable carbon and nitrogen isotope analysis and mixing models were combined to investigate the influence of water levels on the diet and isotopic composition of Poyang Lake fish and invertebrates.Five potential food sources (seston,benthic organic matter,aquatic macrophytes,attached algae,and terrestrial plants),4 species of invertebrates,and 10 species of fish were collected from the lake area during dry and wet seasons between January 2009 and April 2010.The δ 13C values of invertebrates and most fish were within the range of δ 13C values of the potential food sources for both seasons.The δ 13C values of invertebrates and most fish were lower in the dry season than in the wet season,whereas the δ 15N values exhibited different patterns for different species.Mixing models indicated that the most important food sources for common lake fauna were seston in the dry season and aquatic macrophytes and terrestrial plants in the wet season.The fauna were more omnivorous in the wet season than in the dry season.The food web dynamics of Poyang Lake are strongly influenced by changes in the abundance and accessibility of different basal food sources that occur because of seasonal flood pulses.The trophic links within the aquatic communities of Poyang Lake are modified by water-level fluctuations.WANG YuYu YU XiuBo LI WenHua XU Jun CHEN YuWei FAN Na 2011Chinese Science Bulletin2011,56,26:11
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