新乡市居民乡村旅游决策行为及影响因素研究

居民乡村旅游决策行为受众多因素影响,筛选影响乡村旅游决策行为的关键因子,将为景区管理部门提升景区吸引力提供重要依据。本研究筛选了12项观测指标,从4个维度分析了新乡市居民的乡村旅游决策行为,构建了基于AMOS结构方程的决策模型。结果表明：居民收入水平、休闲时间和受教育程度是影响乡村旅游决策的重要因素。景区形象对旅游决策的直接影响最大,表明景区自身因素是促使居民做出最终决策的直接因子。旅游攻略主要通过旅游期望对决策产生影响。提高居民收入水平和乡村旅游景区品牌知名度将对城市居民乡村旅游决策的形成产生正向影响。     

Formal Models for Hybrid Systems

Hybrid systems are reactive systems that intermix discrete and continuous components. Usually, the continuous components are modeled by differential equations, while the discrete components are modeled by discrete event systems or automata. Several important formal models for specifying hybrid systems are introduces, and a new computational model of hybrid systems hybrid transition system(HTS) is presented by extends fair transition systems(FTS).     

Data Analysis Method for Neural Network Based on Short-term Load Forecasting

In neural network based short-term load forecasting, complexity and redundancy of input data have a negative effect on network training efficiency and forecasting precision. Focusing on solving this problem, a multiple method of data processing is developed. Firstly a method called input variable contribution analysis is applied, which divides input variables into primary variables and minor variables according to their contribution to network output. Minor variables are tossed out. Then principal component analysis is applied to primary variables to eliminate linear correlation among them, thus reduce the variable dimension. Based on this method, the main components are gotten, and then simplified network structure is designed. The result shows that after data processing, the training time is reduced noticeably and forecasting precision is enhanced.     

a rational method for defining damage variables in one dimension

To address the issue of whether it is rational to define damage variables through the degradation of elastic modules, we essentially clarified which material module should be used to describe the damage variables in unidimensional cases, and pointed out that the reference undamaged working state of material was needed firstly in order to measure the degree of damage if the strain equivalence hypothesis was used. We maintained it was baseless to consider the linear stress strain working state as an undamaged reference state. We deduced a rational definition of elastic and elasto plastic damage variables. We stated that the degradation of an unloading module can be used to define the damage variables. To illustrate the definition of damage variables, we presented an example of establishing a damage constitutive equation of concrete in compression, validate the elastic strain equivalence hypothesis, and provide an appropriate approach for establishing a damage constitutive model.     

Transform of Orthogonal Double Complex Variables

By article \ the paper puts forward a concept of orthogonal double complex variables space. Its conformal transform and its typical form of transform are doscissed, such as three dimensional complex space square transform, space rukovski transform.     

Hybrid Intelligent Method for Dynamic Reactive Power Optimization

In dynamic reactive power optimization problem(DRPO), action number constraints of discrete variables should be considered.By integrating immune genetic algorithm(IGA) and nonlinear interior point method(NIPM), a hybrid method for DRPO is proposed.First,the original DRPO problem is converted to a continuous optimization problem by relaxing the discrete variables,and the solution is obtained by NIPM.Then,according to the feature of control variables,the original DRPO problem is decomposed into a continuous optimization sub-problem and a discrete optimization sub-problem.The discrete optimization sub-problem is solved by IGA,and the continuous one is solved by NIPM.By solving the two sub-problems alternately,the optimal solution of the DRPO can be obtained.The proposed hybrid method combines advantages of IGA and NIPM,and finds the approximate optimal solution of DRPO.Numerical simulations on the IEEE 14 bus system illustrate that the proposed hybrid method is effective.     

Contribution of Weather Variables to Genotype X Environment Interaction in Grain Sorghum1

Genotype × environment (GE) interactions are a major problem in plant breeding programs that involve testing in diverse environments. These interactions can reduce progress from selection. Few studies have characterized the effects of weather variables on GE interactions in sorghum (Sorghum bicolor [L.] Moench). The present investigation estimated the contribution of environmental index, (?, or mean yield of all cultivars in jth environment minus ?. xor overall mean yield for all cultivars and all environments), rainfall, minimum and maximum temperature, and relative humidity, to GE interaction. Yield means of 5 full-season and 10 medium-season grain sorghum hybrids grown during 1986—1988 at four locations were used in the study. The GE interaction was significant and partitioned into σ²_i, components assignable to each genotype. Weather variables (covariates) were used to remove heterogeneity from the GE interaction. The remainder of the GE interaction variance was partitioned into variance components (s²_i) assignable to each genotype. In both maturity groups, the environmental index removed most, although non-significant, heterogeneity from the GE interaction sums of squares. Of all weather variables, preseason and seasonal rainfall contributed most to the GE interaction sums of squares.     

Simulation of The Torque Control System of Motor for Hybrid Vehicle

A strategy for induction motor control based on the grade of errors is developed to improve the performance of hybrid vehicle drive system. The stator flux error, electric magnetic torque error and flux position angle are used as control variables, and rules for the switching states are chosen according to the errors and the principle of the Direct Torquc Control. This strategy improves efficiently the electric magnetic torque response of the system. The result of simulation shows that this strategy is an ideal control strategy of hybrid vehicle, which can make the motor generate the electric magnetic torque efficiently, steadily and quickly.     

THE INSERTING SYNTHETICAL METHOD FOR COMPILING NETWORK STATE EQUATION

This paper begins with the analysis of factors affecting the esta-blishmet of network state equations. On the basis of characteristics of networkclement, a rational formntation order of elements as twigs and links is proved.According to the order, a best tree can be drawn, which is helpful to for-mulate state equations, Two examples are enumerated On the basis of the besttree, topological equations of network are written. By inserting operationswith both topological equations and characteristic formulas, a standard stateequation is derived as a result of eliminating the undesired variables. Thismethod is simpler and more convenient as compared with the others in theand has advantage of both the topological method and the direct operations,method.     

A Finite Element Method for Quasi Static Problems of Two phase Porous Media

For the quasi static problems of two phase porous media,the velocity variable of fluid phase can be eliminated as the viscosity of fluid is neglected.The corresponding governing equations,with displacement of solid phase and pore pressure as basic variables,as well as the boundary and initial conditions are given out.Finally a mixed finite element formula with u S-p variables is obtained with weighted residual method.This method has lesser nodal variables and higher accuracy of pressure distribution.     

芝麻杂交种生长动态优势的研究

本试验探讨雄性不育二系杂交种豫芝９号生长动态优势，以以亲和豫芝４号为对照，用Ｌｏｇｉｓｔｉｃ生长方程描述其器官生长及干物质积累等１０个怀状的增长过程。比较结果表明，豫芝９号生长发育过程具有的前快后缓有效生长量大的特点。前期持续时间短、中期各器官生长及干物质合成速度愉，形态建成早。各器民干重的ＧＲ１、ＧＲ２和ＧＲｇ与产量显著上关。生长后期即灌浆成熟期持续时间长，根系与生殖器这干物质积累快，盯应ＧＥ３     

Numerical Analysis for Torsion of Prismatic Bars with Sectorial Cross-section

In mechanical design and application, in order to calculate torsion angle and shear stresses of prismatic bars with seetorial cross-section undergoing extemal couples, the numerical method is presented. The torsion equation is nonhomogeneous partial differential equation. First, using the method of separation of variables, torsion stress function is acquired in polar coordinate. Then, the method of boundary collocation is improved to calculate the undetermined parameters. Finally,approximate numerical solutions of stress function and shear stresses in cross-section are obtained. It is given the several calculation results of shear stresses of prismatic bars with different vertex angles. These results show that the method has some precision and application feasibility in engineering design. The method of separation of variables is combinied with the method of boundary collocation simplified calculation process.     

群体密度对提型杂种小麦产量性状及其杂种优势的影响

本文研究了群体密度对提型杂种小麦产量性状及其杂种优势的影响.结果表明:各性状在密度间都存在着显著差异.单株穗数、穗粒数和千粒重随密度增加而下降,籽粒产量与密度呈二次抛物线关系.平均穗粒数和单株穗数的杂种优势在产量杂种优势形成中的直接作用是低密度高于高密度;千粒重的杂种优势在产量杂种优势形成中的直接作用是低密度低于高密度;通过对杂种小麦产量及杂种优势标准化联立方程组求解和对产量回归方程求导的方法,确定了杂种小麦的适宜密度范围为每亩8.5～13万株,最后提出了适当降低杂种小麦密度应采取的栽培措施.     

芝麻杂种优势的生长解析

通过对芝麻杂种8809及其亲本(A和B)各器官干物质积累的系统观测,用微机模拟出各自的Logistic生长方程,以最终生长量、平均生长强度和最大生长强度对各器官的优势表现进行动态分析。结果表明,芝麻杂交种及亲本各器官的生长曲线均呈“S”型;除根茎外,杂交种各器官生长曲线拐点均介于两亲本之间,在最终生长量、平均生长强度和最大生长强度方面,杂种均比亲本表现出较强优势,而且杂种整株和营养器官的生长优势比其生殖生长优势更强。在出苗后53～64天之间,杂种生殖生长强度显著高于两亲本。     

Mixed Finite Element Method for Dynamic Problems of Fluid Saturated Biphasic Porous Media

Based on the fluid saturated biphasic porous media model deduced from mixture theory,a finite element formulation with u S u F p variables for dynamic response analysis is given out.This method overcomes the difficulty of choosing suitable penalty parameter in penalty finite element method,and the accuracy of pressure distribution obtained with the mixed finite element method is higher than the penalty finile element method.An iterative solution method is suggested to solve the system of equations whose coefficient matrices are non positive definite.It is concluded from patch test that the order of interpolation function for pressure variables must be higher than that of displacement variables of solid phase.     

不同林龄杂交楝(Azadirachta indica×Melia azedarach)人工林土壤水土保持功能研究

为了明确林龄对杂交楝（印楝×苦楝）人工林土壤水土保持功能的影响,通过测定土壤持水能力、渗透能力和抗蚀能力来综合评价不同林龄杂交楝人工林保持水土功能。结果表明,随着杂交楝林龄增加,林地土壤孔隙结构得到改善、持水性能增加、渗透能力增大,提高了土壤水稳性指数,增加了土壤抗蚀性,土壤水土保持功能得到增强。3年生杂交楝林分的土壤持水性能、渗透能力和抗蚀性与1年生林分之间无显著差异,5年生杂交楝林地各指标均比1年生和3年生林分有显著提高。5年生杂交楝林地的土壤最大持水量、总孔隙度、非毛管孔隙度、平均渗透速率和水稳性指数分别比1年生林地增加18.6%、11.4%、19.8%、45%、30.1%。因此,种植杂交楝可以在短期内提高林分的土壤水土保持功能,在山地丘陵地区值得大力发展杂交楝。     

Statistical methods for classifying genotypes

In genetic resource conservation and plant breeding, multivariate data on continuous and categorical traits are collected with the objective of selecting genotypes and accessions that best represent the entire population or gene collection with the minimum loss of genetic diversity. Therefore, the best numerical classification strategy is the one that produces the most compact and well-separated groups, that is, minimum variability within each group and maximum variability among groups. In this study, we review geometric classification techniques as well as statistical models based on mixed distribution models. The two-stage sequential clustering strategy uses all variables, continuous and categorical, and it tends to form more homogeneous groups of individuals than other clustering strategies. The sequential clustering strategy can be applied to three-way data comprising genotypes × environments × attributes. This approach groups genotypes with consistent responses for most of the continuous and categorical traits across environments. This revised version was published online in July 2006 with corrections to the Cover Date.     

利用高光谱参数预测水稻叶片叶绿素和籽粒蛋白质含量

通过温室水培试验,测定2个品种、4个供氮水平的水稻剑叶在抽穗期后不同生育期的高光谱反射率,及对应叶片的叶绿素、全氮以及籽粒蛋白等生化组分的含量。结合水稻光谱曲线特征以及氮素营养胁迫特点,利用统计相关分析法,研究了9个植被指数和8个微分参数与叶片叶绿素、全氮含量的相关性,结果表明这些相关性均达到正显著水平     

Truss Structure Shape Optimization withDifferential Evolution Algorithm

Differential Evolution (DE) was introduced to get the global optimum and overcome the difficulties encountered by coupling two types of design variables in the shape optimization of truss structures with stress, geometry, and local stability constraints. The basic principle of DE algorithm was presented in detail first, and then mathematical model for shape optimization of truss structures was presented, in which two types of design variables, such as the node coordinates and section areas, were considered simultaneously. Several classical problems were solved with DE algorithm, and the results were compared with those using the other optimization methods. It was shown that DE algorithm had good convergence and stability and could be applied for shape optimization of truss structures effectively.     

Heat dissipation optimization of DC-DC and IPU for hybrid electric vehicle

Due to the bad heat dissipation of the existing heat dissipation structure of DC-DC and IPU for hybrid electric vehicle(HEV), the temperature of DC-DC and IPU will rise during the running process, which in turn decreases the stability and reliability of the hybrid electric system. Aiming at this problem, a three-dimensional, transient heat dissipation model is built for DC-DC and IPU heat dissipation structure based on the mass, momentum and energy conservation equations. By using computational fluid dynamics (CFD) software, flow field and temperature field of DC-DC and IPU heat dissipation structure are numerically simulated. Based on the simulation, and combined with heat transfer theory, an improvement scheme of heat dissipation structure is proposed. The simulation results and experiment results of thermal performance and temperature rise show that the improvement scheme can improve the thermal performance, and decrease the temperature rise of DC-DC and IPU effectively, thus satisfy the application requirements in HEV.