文书档案保管期限表的量化演变

文书档案的保管对于其应用和信息提取具有重要作用和影响。而随着时代的发展,文书档案保管期限表也在发生变化,通过其量化演变则可以窥探到其鉴定标准的掌握,能够看出文书档案保管的发展演变规律。基于此,本文就文书档案保管期限表的量化演变进行分析研究,希望可以为文书档案的更好管理提供借鉴。

坡面细沟侵蚀形态演变与量化研究评述

坡面细沟形态是一个降雨驱动下侵蚀产沙的微地形动态响应系统,这一地形因素体现着坡面侵蚀动力学各要素及其相互作用,是基于物理过程的水蚀预报模型的关键部分。要建立具有物理意义的坡面侵蚀产流产沙预报模型,就必须从地形角度对细沟形态及其演化过程进行深入研究。评述了近年来国内外在坡面细沟形态演变与量化领域的相关研究成果,从理论研究和观测方法两方面剖析了制约研究发展的因素,提出了推动该研究发展的对策,即:构建细沟形态量化参数评价标准,从建立"状态+时间"综合量化模式入手,以坡面细沟形态为切入点,研究一个连续降雨过程中细沟形态的发育过程与降雨侵蚀产沙过程的关系,定量揭示坡面侵蚀响应规律。

Energy conversion of rocks in process of unloading confining pressure under different unloading paths

Based on energy theory and tests of rocks with initial confining pressures of 10, 20 and 30 MPa under different unloading paths, the processes of strain energy conversion were investigated. The absorbing strain energy for axial compression, the dissipating strain energy for plastic deformation and cracks propagation, the expending strain energy for circumferential deformation, and the storing and releasing elastic strain energy were considered. Unloading paths included the condition of fixing axial pressure and unloading axial pressure, increasing axial pressure and unloading confining pressure, as well as unloading axial pressure and confining pressure simultaneously. Results show that expending strain energy for circumferential deformation has mainly evolved from absorbing strain energy for axial compression in three unloading paths during unloading processes. Dissipating strain energy is significantly increased only near the peak point. The effect of initial confining pressure on strain energy is significantly higher than that of unloading path. The strain energy is linearly increased with increasing initial confining pressure. The unloading path and initial confining pressure also have great influence on the energy dissipation. The conversion rate of strain energy in three paths is increased with increasing initial confining pressure, and the effect of initial confining pressure on conversion rate of strain energy is related with the unloading paths.

Identification and Evolution of Groundwater Chemistry in the Ejin Sub-Basin of the Heihe River, Northwest China

Hydro-chemical characteristics of groundwater and their changes as affected by human activities were studied in the Ejin Sub-Basin of the Inner Mongolia Autonomous Region, China, to understand the groundwater evolution, to identify the predominant geochemical processes taking place along the horizontal groundwater flow path, and to characterize anthropogenic factors affecting the groundwater environment based on previous data. The concentrations of major ions and total dissolved solids （TDS） in the groundwater showed a great variation, with 62.5% of the samples being brackish （TDS ≥ 1 000 mg L^-l）. The groundwater system showed a gradual hydro-chemical zonation composed of Na^＋ -HCO3^-, Na^＋ -Mg^2＋ -SO4 ^2 -Cl^-, and Na^＋ -Cl^-. The relationships among the dissolved species allowed identification of the origin of solutes and the processes that generated the observed water compositions. The dissolution of halite, dolomite, and 2- gypsum explained, in part, the presence of Na^＋, K^＋, Cl^-, SO^4 , and Ca^2＋, but other processes, such as mixing, Na^＋ exchange for Ca^2＋ and Mg^2＋, and calcite precipitation also contributed to the composition of water. Human activity, in particular large-scale water resources development associated with dramatic population growth in the last 50 years, has led to tremendous changes in the groundwater regime, which reflected in surface water runoff change, decline of groundwater table and degeneration of surface water and groundwater quality. Solving these largely anthropogenic problems requires concerted, massive and long-term efforts.

Extension of Variable Separable Solutions for Nonlinear Evolution Equations

We give the generalized definitions of variable separable solutions to nonlinear evolution equations, and characterize the relation between the functional separable solution and the derivative-dependent functional separable solution. The new definitions can unify various kinds of variable separable solutions appearing in references. As application, we classify the generalized nonlinear diffusion equations that admit special functional separable solutions and obtain some exact solutions to the resulting equations.

Localized Excitations in a Sixth-Order （1＋1）-Dimensional Nonlinear Evolution Equation

In this letter, by means of the Lax pair, Darboux transformation, and variable separation approach, a new exact solution of a sixth-order (1+ 1)-dimensional nonlinear evolution equation, which includes some arbitrary functions,is obtained. Abundant new localized excitations can be found by selecting appropriate functions and they are illustrated both analytically and graphically.

Exact Solutions of Some （1＋1）-Dimensional Nonlinear Evolution Equations

By means of the variable separation method, new exact solutions of some （1 ＋ 1）-dimensionaJ nonlinear evolution equations are obtained. Abundant localized excitations can be found by selecting corresponding arbitrary functions appropriately. Namely, the new soliton-like localized excitations and instanton-like localized excitations are presented.

Modeling Evolution of Weighted Clique Networks

We propose a weighted clique network evolution model, which expands continuously by the addition of a new clique （maximal complete sub-graph） at. each time step. And the cliques in the network overlap with each other. The structural expansion of the weighted clique network is combined with the edges＇ weight and vertices＇ strengths dynamical evolution. The model is based on a weight-driven dynamics and a weights＇ enhancement mechanism combining with the network growth. We study the network properties, which include the distribution of vertices＇ strength and the distribution o~ edges＇ weight, and find that both the distributions follow the scale-free distribution. At the same time, we also find that the relationship between strength and degree of a vertex are linear correlation during the growth of the network. On the basis of mean-field theory, we study the weighted network model and prove that both vertices＇ strength and edges＇ weight of this model follow the scale-free distribution. And we exploit an algorithm to forecast the network dynamics, which can be used to reckon the distributions and the corresponding scaling exponents. Furthermore, we observe that mean-field based theoretic results are consistent with the statistical data of the model, which denotes the theoretical result in this paper is effective.

Soliton Motion in （1＋1）-Dimensions

By using the variable separation approach, which is based on the corresponding Backlund transformation, new exact solutions of a （1＋1）-dimensional nonlinear evolution equation are obtained. Abundant new soliton motions of the potential field can be found by selecting appropriate functions.

Study of elastic-plastic damage model of cement consolidated soil with high organic content

On the basis of elastic-plastic damage model of cement consolidated soil,the authors took organic contents into reasonable damage variable evolution equation in order to seek relation between the organic contents and parameters in the equation,and established the elastic-plastic damage model of cement consolidated soil considering organic contents.The results show that the parameters change correspondingly with difference of the organic contents.The higher the organic contents are,the less the valves of the parameters such as elastic modulus(E),material parameters(K,n) and damage evolution parameter(ε) become,but the larger strain damage threshold value(εd) of the sample is.Meanwhile,the calculation results obtained from established model are compared with the test data in the condition of common indoors test,which is testified with reliability.

New Exact Solutions of (1+1)-Dimensional Coupled Integrable Dispersionless System

This paper applies the exp-function method, which was originally proposed to find new exact travelling wave solutions of nonlinear evolution equations, to the Riccati equation, and some exact solutions of this equation are obtained. Based on the Riccati equation and its exact solutions, we find new and more general variable separation solutions with two arbitrary functions of （1＋1）-dimensional coupled integrable dispersionless system. As some special examples, some new solutions can degenerate into variable separation solutions reported in open literatures. By choosing suitably two independent variables p（x） and q（t） in our solutions, the annihilation phenomena of the fiat-basin soliton, arch-basin soliton, and fiat-top soliton are discussed.

Temporal Evolution of Carbon Storage in Chinese Tea Plantations from 1950 to 2010

Tea （Camellia sinensis）, an economically important crop grown in mountain regions, has been planted for thousands of years in South China. Tea plantations can potentially act as carbon （C） sink in local agrosystems due to their high plant biomass and provide soil conservation service. To assess the contribution of tea plantations to C sequestration, the chronosequence variations of C storage were assessed in the plants and soils （0-20 cm） of tea plantations in China from 1950 to 2010, and then the inter-annual and decadal variabilities of total C storage were estimated. TotM C stocks in tea plants and soils in 2010 were 34.4 and 93.45 Tg, respectively. Carbon sequestration from 1950 to 2010 was 30.6 and 39.0 Tg in the plants and soils, respectively. The highest C sequestration happened during the 1980s and the lowest during the 1950s. The decadal average C sequestration rate ranged from 20.4 to 113.9 g m2 year-1 in the standing tea plants, and from 54.6 to 98.8 g m-2 year-1 in soils during the period of 1950 to 2010. The average ratio of C storage in soils to that in plants was 3.00 ± 0.35 before 1970 and 2.44 ±0.18 after 1970. The results suggested that tea plantation ecosystems made an important contribution to the C sinks in Chinese tea-producing regions.

On Integrable Properties for Two Variable-Coefficient Evolution Equations

With the help of the extended binary Bell polynomials, the new bilinear representations, Backlund trans- formations, Lax pair and infinite conservation laws for two types of variable-coefficient nonlinear integrable equations are obtained, respectively, which are more straightforward than previous corresponding results obtained. Finally, we obtain new multi-soliton wave solutions of a reduced soliton equations with variable coefficients.