characteristic

摘要： In order to comprehensively understand the water quality in Yinma River Basin,and to analyze the spatial-temporal variation characteristics of water quality over the years and the causes of water pollution,15 sections were selected in the Yinma River Basin.Based on the water quality monitoring data in the past decade,7 evaluation indexes including dissolved oxygen(DO),5-day biochemical oxygen demand(BOD_(5)),permanganate index(COD_(MN)),chemical oxygen demand(COD),ammonia nitrogen(NH_(4)-N),total phosphorus(TP)and total nitrogen(TN)were determined,according to the Environmental Quality Standard for Surface Water(GB3838-2002)and the historical monitoring data of rivers.The water quality of 15 sections in Yinma River Basin was comprehensively evaluated,and the water quality categories and the evolution of river water quality were analyzed.The pollution sources of Yinma River Basin were analyzed,and the constructive countermeasures were put forward according to the conclusions.

摘要： The Alagxa Plateau, in the margin of the northeastern Tibetan Plateau, is one of the most important dust source areas in East Asia, and the widespread sandy desert in the area is important both as a reservoir and a source of eolian silty. The northeastern margin of the Tibetan Plateau is one of the most actively-growing mountain belt on earth, and has large amounts of debris, with masses of fine grained material, which were continuously mobilized and deposited in the Alagxa Plateau by rivers, forming broad alluvial fans. It is possible that the role of fluvial sediments as a source of silty dust in the Alagxa Plateau has been underestimated. In this study, we test this hypothesis by investigating the iron mineralogical and geochemical characteristics of the fluvial sediments and the surface material of the sandy desert in the Alagxa Plateau, and comparing them with paleo-eolian dust deposits(loess) in the adjacent Chinese Loess Plateau(CLP) to investigate the possible linkages among the fluvial sediments, sandy desert and the last glacial loess of the CLP. The results show that sandy desert typically have high contents of goethite, and high ratios of goethite to hematite, similar to the fluvial sediments in the Alagxa Plateau. Based on the major element characteristics, field investigations and the results of previous studies, we found a genetic link between the silt component of the fluvial sediments and the sandy desert in the Alagxa Plateau with high value of Gt(goethite) and similarity of the Gt/(Hm(hematite)+Gt) ratio. But the silt component of the sandy desert main come from the adjacent fluvial sediments. The iron mineralogical characteristics(χ(magnetic susceptibility), χARM(anhysteretic susceptibility), SIRM(saturation isothermal remanent magnetization) and SIRM_(AF100 mT)(SIRM demagnetized at 100 mT)) of the CLP samples overlap with those of the fluvial sediments in the Alagxa Plateau, but there is a mismatch with the sandy desert samples. This suggests that the fluvial sediments are the source of a large amount of silty material which could be transported to the CLP. Therefore, we conclude that the fluvial sediment in the Alagxa Plateau is an important source of eolian silt, which is deposited in downwind region, and that this source has been previously underestimated.

摘要： We prove that the density function of the gradient of a sufficiently smooth function , obtained via a random variable transformation of a uniformly distributed random variable, is increasingly closely approximated by the normalized power spectrum of ?as the free parameter . The frequencies act as gradient histogram bins. The result is shown using the stationary phase approximation and standard integration techniques and requires proper ordering of limits. We highlight a relationship with the well-known characteristic function approach to density estimation, and detail why our result is distinct from this method. Our framework for computing the joint density of gradients is extremely fast and straightforward to implement requiring a single Fourier transform operation without explicitly computing the gradients.

摘要： Tudor dynasty was a transitional period from feudalism to capitalism and was considered as a golden age in the history of British absolute monarchy.During this period,the language English has changed,and the linguistic and cultural characteristics for the great changes with the help of early English communication corpus are worthy of further discussion.

摘要： Soil Water Retention Characteristics (SWRC) models have been widely used in many applications. Presently, there are many models in the literature and many more still being developed so much so that it is confusing which model to prefer. The current choice of the appropriate model to use has not been well guided by any incisive research on the predictive performance of these models. Consequently, SWRC model applications have been largely moved by convenience. This study used a global dataset to evaluate 12 commonly used SWRC models. The measured data onto which the models were evaluated was grouped into different soil depths and different regions of the world. The evaluation used correlation, Nash-Sutcliffe efficiency, and residual standard error statistics to choose the best overall performing model and models for each category. It gives an indication of the type of SWRC models to use in different regions of the world and depths of sampling. The suitability of the models to regions showed that the Fredlund and Xing model had the best performance in subsoils in Africa;Omuto in Southern Asia;and van Genuchten in subsoils of the other regions. It is recommended that many more models be tested using the procedures in this study so that benchmarks can be established on SWRC model selection suitable for various regions.

摘要： In this case study, we would like to illustrate the utility of characteristic functions, using an example of a sample statistic defined for samples from Cauchy distribution. The derivation of the corresponding asymptotic probability density function is based on [1], elaborating and expanding the individual steps of their presentation, and including a small extension;our reason for such a plagiarism is to make the technique, its mathematical tools and ingenious arguments available to the widest possible audience.

摘要： The probability distributions of wave characteristics from three groups of sampled ocean data with different significant wave heights have been analyzed using two transformation functions estimated by non-parametric and parametric methods. The marginal wave characteristic distribution and the joint density of wave properties have been calculated using the two transformations, with the results and accuracy of both transformations presented here. The two transformations deviate slightly between each other for the calculation of the crest and trough height marginal wave distributions, as well as the joint densities of wave amplitude with other wave properties. The transformation methods for the calculation of the wave crest and trough height distributions are shown to provide good agreement with real ocean data. Our work will help in the determination of the most appropriate transformation procedure for the prediction of extreme values.

摘要： Rayleigh wave is an interference wave of longitudinal wave and transverse wave which propagate along the free surface of solids. There remains a dispute about the number of Rayleigh waves in viscoelastic media until now, which is an essential problem of Rayleigh wave propagation. The purpose of this study is to propose a brief way of handling this essential problem within half-space Kelvin viscoelastic media. Starting from the dynamic equations of transverse wave and longitudinal wave based on Kelvin viscoelastic model, this study sets the complex wave number as a variable, introduces complex moduli and complex exponential factors, then a characteristic equation of Kelvin viscoelastic Rayleigh wave in half space is derived and simplified support for analysis of its uniqueness. After reviewing mathematical models describing phenomena of having multiple solutions but uniqueness when a natural condition is taken into account, a conjecture is given that the Rayleigh wave in Kelvin viscoelastic media must be unique if we assume a natural condition in accordance with the natural phenomena.

摘要： Accurate evaluation of unsaturated soil properties is critical for the design of geotechnical and geo-environmental structures such as road pavements, foundations, and earth dams. Water retention activity in soils which is used to predict the stability or seepage problems in the ground is one of the key features in unsaturated soil mechanics. Thus, many experimental works have reported on the unsaturated soil properties, and the soil-water characteristic curve (SWCC) test has contributed significantly to the interpretation of matric suction. Since traditional instruments cannot apply stress in SWCC tests, some researchers have developed suction controlled triaxial apparatus, by which SWCC tests are performed under different stress states. Determination of SWCCs under stress conditions similar to those in the field is key for interpretation of the hydro-mechanical behavior of unsaturated soils. This study conducted SWCC tests of unsaturated silt soil in low matric suction ranges under both drying and wetting conditions. The SWCCs were measured under one-dimensional and isotropic confining stresses ranging from 50 to 450 kPa. The micro porous membrane method was used instead of high air entry ceramic disk for controlling relatively low matric suction. The range of matric suction controlled was from 0 to 20 kPa. The study revealed that the measured SWCC in low matric suction ranges seems to be affected by the influence of stress conditions. Isotropic confining stress caused the void structure of the specimen to become dense and consequently, soil moisture flow movement also decreased. The water retention activity was obviously high, and the point regard to air entry value was larger. The study further suggests that the current methods adopted for estimating unsaturated soil properties require further development to take into account the effect of different stress conditions.

摘要： In this paper, the internal flow field and external spray characteristics of the spray gun were simulated and analyzed by establishing a coupling model of the gas-liquid two-phase flow of the spray gun. The spray particle size and cone angle under different gas path pressures were mainly studied. The calculation results showed that the spray particle size distribution had a large span, but the overall spray particle size was small. The liquid flow and the air pressure had a little influence on the spray cone angle. The spray SMD was tested by a three-dimensional particle dynamic analyzer (PDA), and the spray cone angle was photographed with a high-speed camera. The test data was basically consistent with the simulation results. The experimental results showed that the model can accurately simulate the internal flow field of the spray gun and the atomization process of urea. It can be used to analyze the characteristics of urea spray and provide a theoretical basis for the optimal design of urea spray gun.

摘要： From the dialectical relationship between the values of sport and physical behavior, the author researched the general information and characteristics of sports value of Tangshan urban resident with themethod of literature, questionnaires, statistics and so on. From the point of psychology, sociology andeconomics, the author analyzed the characteristics of sports values of Tangshan urban resident theoretically,in order to provide reference and scientific basis for decision-making departments.

摘要： Customer value is the precondition of triggering the customer to buy；the object of supply chain management is to meet customer needs. Enhancement for customer value based on supply chain should oriented by customer demand, driven healthy exercise of knowledge flow, capital flow and logistics in the entiresupply chain by process management in order to realize the maximization of customer value and enhance thecore competitiveness of enterprises.

摘要： Customer value is the precondition of triggering the customer to buy；the object of supply chain management is to meet customer needs. Enhancement for customer value based on supply chain should oriented by customer demand, driven healthy exercise of knowledge flow, capital flow and logistics in the entiresupply chain by process management in order to realize the maximization of customer value and enhance thecore competitiveness of enterprises.

摘要： Customer value is the precondition of triggering the customer to buy；the object of supply chain management is to meet customer needs. Enhancement for customer value based on supply chain should oriented by customer demand, driven healthy exercise of knowledge flow, capital flow and logistics in the entiresupply chain by process management in order to realize the maximization of customer value and enhance thecore competitiveness of enterprises.

摘要： Customer value is the precondition of triggering the customer to buy；the object of supply chain management is to meet customer needs. Enhancement for customer value based on supply chain should oriented by customer demand, driven healthy exercise of knowledge flow, capital flow and logistics in the entiresupply chain by process management in order to realize the maximization of customer value and enhance thecore competitiveness of enterprises.

摘要： Customer value is the precondition of triggering the customer to buy；the object of supply chain management is to meet customer needs. Enhancement for customer value based on supply chain should oriented by customer demand, driven healthy exercise of knowledge flow, capital flow and logistics in the entiresupply chain by process management in order to realize the maximization of customer value and enhance thecore competitiveness of enterprises.

摘要： The implementation of the Treasury Centralized Paying System in university is an important partof the current financial management system reform in China, bringing about a profound impact on and someissues to the university's financial management and accounting.rn However, due to the traditional concept of financialmanagement from universities and relevant reforms lag-grog behind, not only had it brought to the university'sfinancial management impacts, but also new financial management issues remain to be dealt with.

摘要： The implementation of the Treasury Centralized Paying System in university is an important partof the current financial management system reform in China, bringing about a profound impact on and someissues to the university's financial management and accounting.rn However, due to the traditional concept of financialmanagement from universities and relevant reforms lag-grog behind, not only had it brought to the university'sfinancial management impacts, but also new financial management issues remain to be dealt with.

摘要： The implementation of the Treasury Centralized Paying System in university is an important partof the current financial management system reform in China, bringing about a profound impact on and someissues to the university's financial management and accounting.rn However, due to the traditional concept of financialmanagement from universities and relevant reforms lag-grog behind, not only had it brought to the university'sfinancial management impacts, but also new financial management issues remain to be dealt with.