期刊文献+
共找到28篇文章
< 1 2 >
每页显示 20 50 100
三水平正交试验用表与三值逻辑 被引量:3
1
作者 刘心平 《遥测遥控》 1991年第2期89-100,共12页
本文采用谱方法的基本思想,把多水平正交试验的主要数学工具——正交表,变换到多值逻辑域中,再利用多值逻辑的运算规则进行处理。这样,把一个极为复杂的数学问题转化成一个简单的多值组合逻辑设计的问题。本文给出了三水平正交用表的逻... 本文采用谱方法的基本思想,把多水平正交试验的主要数学工具——正交表,变换到多值逻辑域中,再利用多值逻辑的运算规则进行处理。这样,把一个极为复杂的数学问题转化成一个简单的多值组合逻辑设计的问题。本文给出了三水平正交用表的逻辑设计公式,同时亦揭示了三水平交互作用用表的逻辑特征,从而进一步促使正交试验方法在各领域中的推广和应用。 展开更多
关键词 ^^+正交表 ^^+值逻辑 ^^+水平 正交试验
下载PDF
Thermodynamic model for equilibrium solubility of gibbsite in concentrated NaOH solutions 被引量:6
2
作者 李小斌 阎丽 +2 位作者 周秋生 刘桂华 彭志宏 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第2期447-455,共9页
The thermodynamic properties of the most important NaOH-NaAI(OH)4-H20 system in Bayer process for alumina production were investigated. A theoretical model for calculating the equilibrium constant of gibbsite dissol... The thermodynamic properties of the most important NaOH-NaAI(OH)4-H20 system in Bayer process for alumina production were investigated. A theoretical model for calculating the equilibrium constant of gibbsite dissolved in sodium hydroxide solution was proposed. New Pitzer model parameters and mixing parameters for the system NaOH-NaAI(OH)4-H20 were yielded and tested in the temperature range of 298.15-373.15 K. The results show that the proposed model for calculating the equilibrium constant of gibbsite dissolution is applicable and accurate. The obtained Pitzer model parameters of β(0)(NaAl(OH)4)、β(1)(NaAl(OH)4)和CΦ(NaAl(OH)4),Al(OH)4 for NaAI(OH)4, the binary mixing parameter of θ(OH-Al(OH)4-) with OH-, and the ternary mixing parameter of ψ(Na+OH-Al(OH)4-) for AI(OH)4- with OH- and Na+ are temperature-dependent. The prediction of the equilibrium solubility of gibbsite dissolved in sodium hydroxide solution was feasible in the temperature range of 298.15-373.15 K. 展开更多
关键词 Pitzer model sodium aluminate solution GIBBSITE equilibrium constant equilibrium solubility
下载PDF
Fuzzy Synthetic Evaluation of Water Quality of Naoli River Using Parameter Correlation Analysis 被引量:14
3
作者 WANG Jianhua LU Xianguo +1 位作者 TIAN Jinghan JIANG Ming 《Chinese Geographical Science》 SCIE CSCD 2008年第4期361-368,共8页
In order to improve the effectiveness of Fuzzy Synthetic Evaluation (FSE) models, a Parameter Correlation Analysis (PCA) was introduced into the FSE and a case study was carried out in the Naoli River in the Sanjiang ... In order to improve the effectiveness of Fuzzy Synthetic Evaluation (FSE) models, a Parameter Correlation Analysis (PCA) was introduced into the FSE and a case study was carried out in the Naoli River in the Sanjiang Plain, Northeast China. The basic principle of the PCA is that the pairs of parameters which are highly correlated and linear with each other would contribute the same information to an assessment and one of them should be eliminated. The method of the PCA is that a correlation relationship among candidate parameters is examined before the FSE. If there is an apparent nonlinear or curvilinear relationship between two parameters, then both will be retained; if the correlation is significant (p<0.01), and the scatter plot suggests a linear relationship, then one of them will be deleted. However, which one will be deleted? For solving this problem, a sensitivity test was conducted and the higher sensitivity parameters remained. The results indicate that the original data should be preprocessed through the PCA for redundancy and variability. The study shows that introducing the PCA into the FSE can simplify the FSE calculation process greatly, while the results have not been changed much. 展开更多
关键词 Parameter Correlation Analysis (PCA) Fuzzy Synthetic Evaluation (FSE) surface water quality Naoli River Sanjiang Plain
下载PDF
Octreotide in Hennekam syndrome-associated intestinal lymphangiectasia 被引量:8
4
作者 Siham Al Sinani Yusria Al Rawahi Hamed Abdoon 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第43期6333-6337,共5页
A number of disorders have been described to cause protein losing enteropathy (PLE) in children. Primary intestinal lymphangiectasia (PIL) is one mechanism leading to PLE. Few syndromes are associated with PIL; Hennek... A number of disorders have been described to cause protein losing enteropathy (PLE) in children. Primary intestinal lymphangiectasia (PIL) is one mechanism leading to PLE. Few syndromes are associated with PIL; Hennekam syndrome (HS) is one of them. The principal treatment for PIL is a high protein, low fat diet with medium chain triglycerides supplementation. Supportive therapy includes albumin infusion. Few publications have supported the use of octreotide to diminish protein loss and minimize hypoalbuminemia seen in PIL. There are no publications on the treatment of PIL with octreotide in patients with HS. We report two children with HS and PLE in which we used octreotide to decrease intestinal protein loss. In one patient, octreotide increased serum albumin to an acceptable level without further need for albumin infusions. The other patient responded more dramatically with near normal serum albumin levels and cessation of albumin infusions. In achieving a good response to octreotide in both patients, we add to the publications supporting the use of octreotide in PIL and suggest that octreotide should be tried in patients with PIL secondary to HS. To the best of our knowledge, this is the first case report on the use of octreotide in HS-associated PIL. 展开更多
关键词 Hennekam syndrome LYMPHANGIECTASIA OCTREOTIDE Protein losing enteropathy
下载PDF
Fruit shape detection by level set 被引量:2
5
作者 GUI Jiang-sheng RAO Xiu-qin YING Yi-bin 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2007年第8期1232-1236,共5页
A novel approach for fruit shape detection in RGB space was proposed,which was based on fast level set and Chan-Vese model named as Modified Chan-Vese model(MCV) . This new algorithm is fast and suitable for fruit sor... A novel approach for fruit shape detection in RGB space was proposed,which was based on fast level set and Chan-Vese model named as Modified Chan-Vese model(MCV) . This new algorithm is fast and suitable for fruit sorting because it does not need re-initializing. MCV has three advantages compared to the traditional methods. First,it provides a unified frame-work for detecting fruit shape boundary,and does not need any preprocessing even though the raw image is noisy or blurred. Second,if the fruit has different colors at the edges,it can detect perfect boundary. Third,it processed directly in color space without any transformations that may lose much information. The proposed method has been applied to fruit shape detection with promising result. 展开更多
关键词 Machine vision Shape detection Level set Fruit sorting
下载PDF
Mechanical Properties of Asphalt Pavement Structure in Highway Tunnel 被引量:4
6
作者 石春香 郭忠印 《Journal of Shanghai Jiaotong university(Science)》 EI 2008年第2期206-210,共5页
A linear full 3D finite element method (FEM) was performed in order to present the key design parameters of highway tunnel asphalt pavement under double-wheel load on rectangular loaded area considering horizontal con... A linear full 3D finite element method (FEM) was performed in order to present the key design parameters of highway tunnel asphalt pavement under double-wheel load on rectangular loaded area considering horizontal contact stress induced by the acceleration/deceleration of vehicles.The key design parameters are the maximum horizontal tensile stresses at the surface of the asphalt layer,the maximum horizontal tensile stresses at the bottom of the asphalt layer and the maximum vertical shear stresses at the surface of the as- phalt layer were calculated.The influencing factors such as double-wheel weight;asphalt layer thickness;base course stiffness modulus and thickness;and the contact conditions among the structure layers on these key design parameters were also examined separately to propose construction procedures of highway tunnel asphalt pavement. 展开更多
关键词 tunnel asphalt pavement structure three-dimensional finite element method horizontal force horizontal tensile stress vertical shear stress
下载PDF
Research on Precise Trigonometric Leveling in Place of First Order Leveling 被引量:7
7
作者 ZHANG Zhenglu ZHANG Kun +1 位作者 DENG Yong LUO Changlin 《Geo-Spatial Information Science》 2005年第4期235-239,共5页
Through the analysis of the principle, error sources and precision of trigonometric leveling, this paper points out the key problems about first order leveling replaced by trigonometric leveling; and for the first tim... Through the analysis of the principle, error sources and precision of trigonometric leveling, this paper points out the key problems about first order leveling replaced by trigonometric leveling; and for the first time puts forward that, in some given conditions, it is not only feasible but also valuable to replace first order leveling by precise trigonometric leveling, and proves it by experimentation as well. The content and conclusion of this paper have consulting significance and practicable value for our setting down relational criterion and production practice. 展开更多
关键词 electronic distance measurements trigonometric leveling first order leveling surveying for deformation monitoring
下载PDF
Response of Regeneration Diversity of Carex Lasiocarpa Community to Different Water Levels in Sanjiang Plain,China 被引量:5
8
作者 WANG Li SONG Changchun +1 位作者 HU Jinmin YANG Tao 《Chinese Geographical Science》 SCIE CSCD 2010年第1期37-42,共6页
The species diversity at the regeneration stage, inflenced by different water levels, is important for community composition in the later growing season.Regeneration diversity of Carex lasiocarpa community under diffe... The species diversity at the regeneration stage, inflenced by different water levels, is important for community composition in the later growing season.Regeneration diversity of Carex lasiocarpa community under different water levels was studied at two stages, recruitment and adult, in the Sanjiang Plain, Heilongjiang Province, China.The results showed that, at the two growing stages, important value of C.lasiocarpa population and species richness of the community decreased with the increasing water level, while the Simpson and Shannon-Wiener diversity indexes and Pielou evenness index increased.Under different water levels, community diversities were higher at the recruitment stage, while population important values of C.lasiocarpa were higher at the adult stage.Indexes in vegetation evaluation must be chosen prudentially for successful restoration and effective management of wetlands, and especially for wetland restoration, the optimal time should be selected according to the restoration objectives and costs. 展开更多
关键词 water level population dominance species diversity marsh wetland Sanjiang Plain
下载PDF
Phase equilibria for the pseudo-ternary system(NaCl+Na2SO4+H2O)of coal gasification wastewater at T=(268.15 to 373.15)K 被引量:8
9
作者 Haijiao Lu Jingkang Wang +5 位作者 Jun Yu Yuefeng Wu Ting Wang Ying Bao Dou Ma Hongxun Hao 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2017年第7期955-962,共8页
The pseudo-ternary system(Na Cl + Na_2SO_4+ H_2O) of coal gasification wastewater was studied at T =(268.15 to 373.15) K. The solubility and density of the equilibrium liquid phase were determined by the isothermal so... The pseudo-ternary system(Na Cl + Na_2SO_4+ H_2O) of coal gasification wastewater was studied at T =(268.15 to 373.15) K. The solubility and density of the equilibrium liquid phase were determined by the isothermal solution saturation method. The equilibrium solids were also investigated by the Schreinemaker's method of wet residues and X-ray powder diffraction(XRD). According to the experimental data, the phase diagrams were determined. It was found that there was no significant solubility difference on the Na Cl-rich side between the ternary system(Na Cl + Na_2SO_4+ H_2O) in coal gasification wastewater and in pure water. However, the solubility on the Na_2SO_4-rich side of coal gasification wastewater was apparently higher than that of pure water. The increase in the solubility of Na_2SO_4 was most likely caused by the effects of other impurities apart from Na Cl and Na_2SO_4 in coal gasification wastewater. The measured data and phase equilibrium diagrams can provide fundamental basis for salt recovery in coal gasification wastewater. 展开更多
关键词 Pseudo-ternary system Phase equilibria THERMODYNAMICS Waste water Recovery
下载PDF
Energy efficient virtual machine migration approach with SLA conservation in cloud computing 被引量:4
10
作者 GARG Vaneet JINDAL Balkrishan 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第3期760-770,共11页
In the age of online workload explosion,cloud users are increasing exponentialy.Therefore,large scale data centers are required in cloud environment that leads to high energy consumption.Hence,optimal resource utiliza... In the age of online workload explosion,cloud users are increasing exponentialy.Therefore,large scale data centers are required in cloud environment that leads to high energy consumption.Hence,optimal resource utilization is essential to improve energy efficiency of cloud data center.Although,most of the existing literature focuses on virtual machine(VM)consolidation for increasing energy efficiency at the cost of service level agreement degradation.In order to improve the existing approaches,load aware three-gear THReshold(LATHR)as well as modified best fit decreasing(MBFD)algorithm is proposed for minimizing total energy consumption while improving the quality of service in terms of SLA.It offers promising results under dynamic workload and variable number of VMs(1-290)allocated on individual host.The outcomes of the proposed work are measured in terms of SLA,energy consumption,instruction energy ratio(IER)and the number of migrations against the varied numbers of VMs.From experimental results it has been concluded that the proposed technique reduced the SLA violations(55%,26%and 39%)and energy consumption(17%,12%and 6%)as compared to median absolute deviation(MAD),inter quartile range(IQR)and double threshold(THR)overload detection policies,respectively. 展开更多
关键词 cloud computing energy efficiency three-gear threshold resource allocation service level agreement
下载PDF
A Preliminary Study on Traditional Level-trench Method to Prevent Rill Initiation in the Three Gorges Region,China 被引量:1
11
作者 YAN Dongchun WEN Anbang +3 位作者 HE Xiubin SHI Zhonglin XIONG Donghong LONG Yi 《Journal of Mountain Science》 SCIE CSCD 2011年第6期876-881,共6页
The level-trench method is a traditional tillage operation to develop a drainage system on slope land in the Three Gorges region. Before crops are planted, farmers prepare the land with level trenches spaced 3-1o m ap... The level-trench method is a traditional tillage operation to develop a drainage system on slope land in the Three Gorges region. Before crops are planted, farmers prepare the land with level trenches spaced 3-1o m apart, depending on the slope gradient: steeper slopes require shorter distances. Little scientific analysis has been done on the use of traditional level trenches for soil conservation. We conducted a field investigation and simulation experiments, and present a comparison between the spacing of level trenches and the slope length required for rill initiation. The results indicate that the spacing of level trenches in farmland is close to the slope length required for rill initiation in the experimental plots, and regression models of trench spacing with the gradient and the slope length required for rill initiation with the gradient have similar formats; the coefficients of determination (R2) for the two equations are 0.99 and 0.88, respectively. There were some differences between the field survey and experiments, but we conclude that the traditional level-trench method has an important role in preventing rill initiation. 展开更多
关键词 Level trench Rill Initiation Purple Soil Three Gorges Region
下载PDF
Three-dimensional land FD-CSEM forward modeling using edge finite-element method 被引量:3
12
作者 LIU Jian-xin LIU Peng-mao TONG Xiao-zhong 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第1期131-140,共10页
A modeling tool for simulating three-dimensional land frequency-domain controlled-source electromagnetic surveys,based on a finite-element discretization of the Helmholtz equation for the electric fields,has been deve... A modeling tool for simulating three-dimensional land frequency-domain controlled-source electromagnetic surveys,based on a finite-element discretization of the Helmholtz equation for the electric fields,has been developed.The main difference between our modeling method and those previous works is edge finite-element approach applied to solving the three-dimensional land frequency-domain electromagnetic responses generated by horizontal electric dipole source.Firstly,the edge finite-element equation is formulated through the Galerkin method based on Helmholtz equation of the electric fields.Secondly,in order to check the validity of the modeling code,the numerical results are compared with the analytical solutions for a homogeneous half-space model.Finally,other three models are simulated with three-dimensional electromagnetic responses.The results indicate that the method can be applied for solving three-dimensional electromagnetic responses.The algorithm has been demonstrated,which can be effective to modeling the complex geo-electrical structures.This efficient algorithm will help to study the distribution laws of3-D land frequency-domain controlled-source electromagnetic responses and to setup basis for research of three-dimensional inversion. 展开更多
关键词 three-dimensional model frequency-domain electromagnetic method horizontal electric dipole forward modeling edge finite-element
下载PDF
3D Multiphase Piecewise Constant Level Set Method Based on Graph Cut Minimization 被引量:2
13
作者 Tiril P Gurholt Xuecheng Tai 《Numerical Mathematics(Theory,Methods and Applications)》 SCIE 2009年第4期403-420,共18页
Segmentation of three-dimensional(3D) complicated structures is of great importance for many real applications.In this work we combine graph cut minimization method with a variant of the level set idea for 3D segmenta... Segmentation of three-dimensional(3D) complicated structures is of great importance for many real applications.In this work we combine graph cut minimization method with a variant of the level set idea for 3D segmentation based on the Mumford-Shah model.Compared with the traditional approach for solving the Euler-Lagrange equation we do not need to solve any partial differential equations.Instead,the minimum cut on a special designed graph need to be computed.The method is tested on data with complicated structures.It is rather stable with respect to initial value and the algorithm is nearly parameter free.Experiments show that it can solve large problems much faster than traditional approaches. 展开更多
关键词 Piecewise constant level set method energy minimization graph cut SEGMENTATION three-dimensional.
下载PDF
Physiological levels of ATP negatively regulate proteasome function 被引量:4
14
作者 Hongbiao Huang Xiaoyan Zhang +16 位作者 Shujue Li Ningning Liu Wen Elan Emily McDowell Ping Zhou Canguo Zhao Haiping Guo Change Zhang Changshan Yang Guangmei Wen Xiaoxian Dong Li Lu Ningfang Ma Weihua Dong Q Ping Dou Xuejun Wang Jinbao Liu 《Cell Research》 SCIE CAS CSCD 2010年第12期1372-1385,共14页
Intracellular protein degradation by the ubiquitin-proteasome system is ATP dependent, and the optimal ATP concentration to activate proteasome function in vitro is -100 μM. IntraceUular ATP levels are generally in t... Intracellular protein degradation by the ubiquitin-proteasome system is ATP dependent, and the optimal ATP concentration to activate proteasome function in vitro is -100 μM. IntraceUular ATP levels are generally in the low millimolar range, but ATP at a level within this range was shown to inhibit proteasome peptidase activities in vitro. Here, we report new evidence that supports a hypothesis that intracellular ATP at the physiological levels bidirectionally regulates 26S proteasome proteolytic function in the cell. First, we confirmed that ATP exerted bidirectional regulation on the 26S proteasome in vitro, with the optimal ATP concentration (between 50 and 100μM) stimulating proteasome chymotrypsin-like activities. Second, we found that manipulating intracellular ATP levels also led to bidirectional changes in the levels of proteasome-specific protein substrates in cultured cells. Finally, measures to increase intracellular ATP enhanced, while decreasing intraceHular ATP attenuated the ability of proteasome inhibition to induce cell death. These data strongly suggest that endogenous ATP within the physiological concentration range can exert a negative impact on proteasome activities, allowing the cell to rapidly upregulate proteasome activity on ATP reduction under stress conditions. 展开更多
关键词 ATP PROTEASOME REGULATION APOPTOSIS
下载PDF
Effects of Nitrogen Addition on Plant Functional Traits in Freshwater Wetland of Sanjiang Plain,Northeast China 被引量:14
15
作者 MAO Rong ZHANG Xinhou SONG Changchun 《Chinese Geographical Science》 SCIE CSCD 2014年第6期674-681,共8页
To clarify the responses of plant functional traits to nitrogen(N) enrichment, we investigated the whole-plant traits(plant height and aboveground biomass), leaf morphological(specific leaf area(SLA) and leaf dry mass... To clarify the responses of plant functional traits to nitrogen(N) enrichment, we investigated the whole-plant traits(plant height and aboveground biomass), leaf morphological(specific leaf area(SLA) and leaf dry mass content(LDMC)) and chemical traits(leaf N concentration(LNC) and leaf phosphorus(P) concentration(LPC)) of Deyeuxia angustifolia and Glyceria spiculosa following seven consecutive years of N addition at four rates(0 g N/(m2·yr), 6 g N/(m2·yr), 12 g N/(m2·yr) and 24 g N/(m2·yr)) in a freshwater marsh in the Sanjiang Plain, Northeast China. The results showed that, for both D. angustifolia and G. spiculosa, N addition generally increased plant height, leaf, stem and total aboveground biomass, but did not cause changes in SLA and LDMC. Moreover, increased N availability caused an increase in LNC, and did not affect LPC. Thus, N addition decreased leaf C∶N ratio, but caused an increase in leaf N∶P ratio, and did not affect leaf C∶P ratio. Our results suggest that, in the mid-term, elevated N loading does not alter leaf morphological traits, but causes substantial changes in whole-plant traits and leaf chemical traits in temperate freshwater wetlands. These may help to better understand the effects of N enrichment on plant functional traits and thus ecosystem structure and functioning in freshwater wetlands. 展开更多
关键词 nitrogen addition Deyeuxia angustifolia Glyceria spiculosa leaf chemical traits leaf morphological traits whole-planttraits Sanjiang Plain
下载PDF
New approach to develop a 3D non-isothermal computational framework for injection molding process based on level set method 被引量:2
16
作者 Xin Zhuang Jie Ouyang +1 位作者 Chuntao Jiang Qingsheng Liu 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2016年第7期832-842,共11页
The simulation of three-dimensional (3D) non-isothermal, non-Newtonian fluid filling process is an extremely difficult task and remains a challenging problem, which includes polymer melt flow with free surface coupl... The simulation of three-dimensional (3D) non-isothermal, non-Newtonian fluid filling process is an extremely difficult task and remains a challenging problem, which includes polymer melt flow with free surface coupled with transient heat transfer. This paper presents a full 3D non-isothermal two-phase flow model to predict the complex flow in melt filling process, where the Cross-WLF model is applied to characterize the rheological behav- ior of polymer melt. The governing equations are solved using finite volume method with SIMPLEC algorithm on collocated grids and the melt front is accurately captured by a high resolution level set method. A domain exten- sion technique is adopted to deal with the complex cavities, which greatly reduces the computational burden. To verify the validity of the developed 3D approach, the melts filling processes in two thin rectangular cavities (one of them with a cylindrical insert) are simulated. The predicted melt front interfaces are in good agreement with the experiment and commercial software prediction. For a case with a rather complex cavity, the dynamic filling process in a hemispherical shell is successfully simulated. All of the numerical results show that the developed numerical procedure can provide a reasonable orediction for injection molding process. 展开更多
关键词 Injection moldingNon-isothermalFinite voIume/SIMPLEC methodDomain extension techniqueHigh resolution level set method
下载PDF
Spatial Variation of Dissolved Organic Carbon in Soils of Riparian Wetlands and Responses to Hydro-geomorphologic Changes in Sanjiang Plain, China 被引量:7
17
作者 XI Min KONG Fanlong +2 位作者 LYU Xianguo JIANG Ming LI Yue 《Chinese Geographical Science》 SCIE CSCD 2015年第2期174-183,共10页
Spatial variation of dissolved organic carbon(DOC) in soils of riparian wetlands and responses to hydro-geomorphologic changes in the Sanjiang Plain were analyzed through in situ collecting soil samples in the Naoli R... Spatial variation of dissolved organic carbon(DOC) in soils of riparian wetlands and responses to hydro-geomorphologic changes in the Sanjiang Plain were analyzed through in situ collecting soil samples in the Naoli River and the Bielahong River. The results showed that the average contents of DOC for soil layer of 0–100 cm were 730.6 mg/kg, 250.9 mg/kg, 423.0 mg/kg and 333.1 mg/kg respectively from riverbed to river terrace along the transverse directions of the Naoli watershed. The content of the soil DOC was the highest in the riverbed, lower in the high floodplain and much lower in the river terrace, and it was the lowest in the low floodplain. The difference in the content and vertical distribution of DOC between the riverbed and the three riparian wetlands was significant, while it was not significant among the low floodplain, the high floodplain and the river terrace. The variability of soil DOC was related to the hydrological connectivity between different landscape position of the riparian wetlands and the adjacent stream. Extremely significant correlations were observed between DOC and total organic carbon(TOC), total iron(TFe), ferrous iron(Fe(II)) whose correlation coefficients were 0.819, –0.544 and –0.709 in riparian wetlands of the Naoli River. With the increase of wetland destruction, soil p H increased and soil DOC content changed. The correlation coefficients between soil DOC and TOC, TFe, Fe(II) also changed into 0.759, –0.686 and –0.575 respectively in the Bielahong River. Under the impact of drainage ditches, the correlations between soil DOC and TFe, Fe(II) were not obvious, while the soil p H was weakly alkaline and was negatively correlated with soil DOC in the previous high floodplain. It indicates that riparian hydro-geomorphology is the main factor that could well explain this spatial variability of soil DOC, and the agricultural environmental hydraulic works like ditching also must be considered. 展开更多
关键词 dissolved organic carbon(DOC) riparian wetlands spatial variation hydro-geomorphologic changes Sanjiang Plain
下载PDF
Three-dimensional simulation of sintering crunodes of metal powders or fibers by level set method 被引量:1
18
作者 谌东东 郑洲顺 +2 位作者 王建忠 汤慧萍 曲选辉 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第7期2446-2455,共10页
The difference of sintering crunodes of metal powders and fibers is discussed. The mathematical model of the surface diffusion described by the difference in mean curvature is defined as a Hamilton-Jacobi-type equatio... The difference of sintering crunodes of metal powders and fibers is discussed. The mathematical model of the surface diffusion described by the difference in mean curvature is defined as a Hamilton-Jacobi-type equation, and the model is numerically solved by the level set method. The three-dimensional numerical simulations of two metal powders and fibers(the fiber angle is 0° or 90°) are implemented by this mathematical model, respectively. The numerical simulation results accord with the experimental ones. The sintering neck growth trends of metal powders and metal fibers are similar. The sintering neck radius of metal fibers is larger than that of metal powders. The difference of the neck radius is caused by the difference of geometric structure which makes an important influence on the curvature affecting the migration rate of atoms. 展开更多
关键词 metal fiber metal powder sintering crunodes mean curvature three-dimensional simulation
下载PDF
Vegetation Development and Water Level Changes in Shenjiadian Peatland in Sanjiang Plain,Northeast China 被引量:8
19
作者 WANG Chunling ZHAO Hongyan WANG Guoping 《Chinese Geographical Science》 SCIE CSCD 2015年第4期451-461,共11页
This paper documents a 7800-year proxy record from the Shenjiadian peatland on the Sanjiang Plain in Northeast China.High-resolution plant macrofossil and colorimetric humification methods were used to reconstruct the... This paper documents a 7800-year proxy record from the Shenjiadian peatland on the Sanjiang Plain in Northeast China.High-resolution plant macrofossil and colorimetric humification methods were used to reconstruct the vegetation and hydrologic history from a 193 cm-long sedimentary profile.Detrended correspondence analysis(DCA) was applied to transform the raw plant macrofossil data into latent indices of peatland water level.The vegetation community transited from an Equisetum fluviatile community to a Carex lasiocarpa community at approximately 3800 cal yr BP and was followed by a Carex-shrub community at approximately 480 cal yr BP.Based on the plant macrofossil DCA axis 1 scores and humification values,we distinguished four hydrologic periods:a wet period from 7800 cal yr BP to 4500 cal yr BP,dry periods up to 1600 cal yr BP,drier periods until 300 cal yr BP,and the driest period from 300 cal yr BP until the present.Through a comparison with other climate records,we suggest that the East Asian summer monsoon(EAM) was the main driving force for vegetation and water level changes to the Shenjiadian peatland through its impacts on precipitation. 展开更多
关键词 plant macrofossils humification Holocene peatland Northeast China
下载PDF
Three Gorges Dam Controls Sediment Coarsening of the Mud Patch on the Inner East China Sea Shelf 被引量:2
20
作者 MIAO Anyang CHU Zhongxin LI Yingkun 《Journal of Ocean University of China》 SCIE CAS 2016年第3期414-422,共9页
The well-known Three Gorges Dam(TGD) within the Yangtze catchment launched its operation in 2003. The effect of the TGD operation on the sediment size on the East China Sea shelf is rarely known. High resolution(0.5 c... The well-known Three Gorges Dam(TGD) within the Yangtze catchment launched its operation in 2003. The effect of the TGD operation on the sediment size on the East China Sea shelf is rarely known. High resolution(0.5 cm sampling) grain size analysis and 137 Cs and 210 Pb dating of the DH8-1 core were conducted with core collected from the distal part of a main sink for the modern Yangtze sediment entering the sea, the Min-Zhe Coastal Mud Deposits(MZCMD) on the inner East China Sea shelf. The 137 Cs dating results show that the core DH8-1 formed during 1946–2012 with a mean deposition rate of 0.65 cm yr^(-1), indicating that the 0.5 cm sampling for grain size analysis in this local area could reflect environmental changes generally on a one-year time scale. The mean grain size of DH8-1 core sediment that deposited after 2003 is significantly larger than that deposited during 1988–2002. After ruling out other possible factors, we infer that the sediment coarsening of DH8-1 core after 2003 is attributed to the TGD operation which causes the erosion of the Yangtze subaqueous delta. Specifically, the TGD operation significantly intensifies the declining trend of the Yangtze sediment loads to the sea despite no decreased water discharge, which results in extensive erosion of the Yangtze subaqueous delta. The relatively coarse sediment of the subaqueous delta is eroded and resuspended by ocean dynamics and then transported by coastal current, finally depositing on the MZCMD area. In addition, the general sediment fining of core DH8-1 that deposited during 1988–2002, comparing with 1946–1987, is mainly caused by dam construction and soil and water conservation within the Yangtze catchment. Our findings are helpful for better understanding the effects of such a huge dam as the TGD on a sediment sink like the MZCMD of such a large river as the Yangtze River. 展开更多
关键词 Three Gorges Dam environmental effect East China Sea grain size analysis isotopic dating
下载PDF
上一页 1 2 下一页 到第
使用帮助 返回顶部