Vehicle stability control system design using optimal allocation of yaw moment

In order to improve vehicle handling stability,a control system using optimal allocation of yaw moment was designed.The first layer is a linear quadratic regulator (LQR) controller,which optimizes a desired yaw moment to work on the vehicle and calculates reference wheel slip for the target wheel.The second layer of the control system is a PID controller which can track the reference wheel slip rate,and then apply braking torque on the target wheel to make the vehicle stable.Simulations are carried out by using an 8-dof nonlinear vehicle model under different conditions.The simulation results indicate that the designed control system can effectively improve vehicle handling stability.     

Distribution Regularities and Influencing Factors of Shear Stress in High Grade Asphalt Pavement Layers

Based on the Linear Elastic Multi-layer Theory, using the pavement finite-element program, this article discussed the shear stress distribution regularities and influencing factors in high grade asphalt pavement layers. The results demonstrate that the max shear stress appears in surface to 3cm depth span regardless of the material characteristic and thickness in each layer. The major influencing factors on the shear stress are modulus and Poisson ratio of asphalt layer, modulus of base layer. By comparing the database with testing results, to three asphalt layers pavement structure, it is necessary to check the shear strength in wearing layer and midlayer. When checking, the precious position must be found to calculate the max shear stress in each layer.     

豫西黄土区夏玉米非充分灌溉制度研究

豫西黄土区水资源紧缺,为充分利用当地的雨水资源,以非充分灌溉原理和节水农业理论为指导,采用Jensen模型,以夏玉米生长各阶段单位面积上实际产量与可能最大产量之比最大为目标函数,灌溉水量与实际腾发量为决策变量,可分配的水量和计划湿润层内可供利用的水量为状态变量,用动态规划逐次逼近法求解该模型,推求夏玉米的非充分灌溉优化制度。结果表明：优化结果与试验数据相吻合,说明Jensen模型在该地区的适用性。     

Analyse critique d'une methode d'estimation de la conductivite thermique d'un sol in situ

A numerical method for determining the thermal conductivity of a soil in situ is proposed. It requires the measure of the temperature at three levels in the soil. From the knowledge of the boundary conditions (temperatures at the top and the bottom of the soil layer) and an estimation of the initial the mal profile, the temperature at the intermediate level can be calculated by integration of the monodimensional heat conduction equation with a numerical method (finite elements method). The boundary conditions are interpolated by the FOURIER series. The heat capacity is calculated according to the model of DE VRIES. The thermal conductivity is estimated by minimizing the residual sum of squares between calculated and measured temperatures at the intermediate level. The soil layer can be considered either homogeneous or stratified in two sub-layers. Using simulated temperature data, the optimal conditions of use of the method are defined and the sensitivity of the method to errors made on the measure of the temperature and on the position of the temperature probes is studied.In the case of an homogeneous soil layer, the method yields a good estimation of the thermal conductivity (error ≤1%) with a 4 hours period of estimation, whatever the position of the intermediate probe. The more precise estimation is obtained with an intermediate probe placed at the middle of the layer and with a high thermal amplitude. The method is not sensitive to errors made on temperature measures (biased or truncated measures) if the estimation is made on a period of 24 hours. It is highly sensitive to errors made on the position of the temperature probes.In the case of a stratified layer, the method allows to estimate the thermal conductivity of each sub-layer whatever the position of the intermediate probe if the period of estimation is at least 12 hours. The method is very sensitive to errors made on temperature measures (whatever the duration of the estimation period), on the position of the temperature probes and on the position of the limit between the two sub-layers. Therefore, its use for a stratified soil layer seems delicate.     

Distribution Network Structure Planning Based on Multi-population Immune Genetic Algorithm

Distribution Network Structure planning is a complex combinatorial optimization problem, which is difficult to solve properly by using traditional optimization methods. The authors put forward Multiple Population Immune Genetic Algorithm (MPIGA)for optimal planning of distribution network structure, and do optimal search to different aspects of optimization goals. During the genetic evolution process, biologic immune mechanism is introduced to do some immune operator operation on chromosomes of each population, which can interact mutually by the shift of excellent units. By this way, it can effectively prevent population retrogression, promote diversity and the whole optimal searching ability of genetic algorithm. In order to minimize network annual expenditure, a mathematic model is established. The optimal solution is obtained by this algorithm, which has been illustrated effectively by specific examples at the same time.     

ENERGY-SAVING AND OPTIMAL HIERARCHICAL CONTROL OF WATER PLANT

In this paper, on condition that the production processes in water plant are related with each other, a new coordinative algorithm is presented, using a hierarchical control structure and taking the equivalent efficiency of the pump station as coordinative variable. In this way, the problem of optimal control of the complex delay system is solved. Simulation shows that great energy-saving efficiency may be obtained by the above method.     

Determination of the Binding Constant Between Sodium Houttuyfonate and Human Serum Albumin by Capillary Electrophoresis

The objective function of minimum cost is established for double layer torsional reticulated shell, taking the rise-span ratio, grid size and shell thickness as design variables. Based on the exhaustion and 0.618 methods, the computing program LSD has been developed. For the double layer torsional reticulated shell with the span of 50 m to 80m, the optimal grid size and thickness have been obtained for systems of light roof materials with different spans. Empirical formulas are deduced from the results.     

春秋季冷空气过程对不同养殖水体水温的影响分析

为了探讨冷空气活动对不同大小的水体水温造成的影响,利用2011～2012年春秋季冷空气资料及两个不同水体在冷空气发生前后时段的逐层水温资料,采用统计分析法,研究分析了各层水温对冷空气活动的响应和变化,建立了逐层水温降幅模型。结果表明：1）冷空气过后,浅表层水温比深层水温降幅大,大水体的水温极低值出现时间比小水体明显偏晚;2）冷空气强度越大,大小水体的水温降幅差异越大,小水体更容易降温;3）小水体的水温降幅与气象要素的相关性要好于大水体,且浅层水温更易受气象要素的影响,深层水温尤其是大水体的深层水温受外界环境影响明显较小;4）建立的水温降幅模型中,小水体模拟效果较好,大水体的浅层10～50cm层模拟效果相对较好,而深层100～150cm效果相对较差。据此,利用相关气象要素建立的预报模型可在春秋季水产养殖关键期有冷空气活动时提供生产指导和预警服务。     

生态农业观光园景观评价体系研究

为了建立适用于各种类型的生态农业观光园的景观评价系统,了解各景观元素在生态农业观光园景观营造中的作用,笔者应用层次分析法的原理,构建一套完整的生态农业观光园景观评价指标体系,运用专家咨询法和萨蒂(Satty)制定的1~9标度法构造判断矩阵,计算出各评价因子的权重。系统运算结果表明,项目层中自然景观的权重远大于人文景观和生产景观,因素层中农业景观权重最大,其重要性高于同项目层下园林植物景观,在指标层中,农业景观总体意象权重最大,其次是物种的多样性,农事体验、农事活动、民风民俗展示、园林建筑总体风格也占有一定的地位。该研究为生态农业观光园的景观设计与营造、等级评定及分级管理和分级指导提供理论依。     

花期不同打尖层数对蚕豆农艺性状及产量的影响

对2个蚕豆品种进行花期打尖处理,研究其主要农艺性状及产量的差异,提出花期打尖处理的最适层数,为蚕豆高产高效栽培提供科学依据。结果表明,随着花期打尖层数的增加,蚕豆株高逐渐增加;单株总荚数、总分枝数（达蚕1号）、有效分枝数和百粒重均先增后减;始荚高度、单荚粒数、总分枝数（成胡15）、主茎节数和荚长受打尖处理影响较小;产量也呈先增加后降低的趋势,并在打尖层数为第8层时达到最大值。相关性分析表明,蚕豆产量与百粒重、有效分枝数和单株总荚数呈显著正相关（P<0.05）;株高与百粒重也呈显著正相关（P<0.05）。回归分析表明,打尖层数与蚕豆产量的关系均为开口向下的抛物线,最适打尖层数为第8~9层。     

3种提取方法对南瓜多糖得率及抗氧化性质的影响

采用热水浸提法、超声法及复合酶法提取南瓜多糖,并对3种方法进行比较。采用乙醇沉淀法得到南瓜粗多糖,比较3种方法所得粗多糖对羟基自由基(.OH)和超氧阴离子自由基(O2-.)的清除效果。结果表明,热水浸提法、超声法及复合酶法的提取率分别为14.8%,15.87%和20.13%,即酶法为最佳方法;复合酶法提取得到的多糖对羟基自由基(.OH)和超氧阴离子自由基(O2-.)的清除效果最好。     

Optimizing Design of Planar Transformers Based on Integrated Software Platform

A method of optimizing planar transformers' design based on integrated software platform iSIGHT is presented.Through integrating the circuit simulation tool Saber and Maxwell 3D to the optimization tool iSIGHT,the parasitic effects on planar transformers are studied carefully.Changing the thickness of the insulator layer between the primary and the secondary can obtain different values of parasitic parameters and a new method to avoid parasitic oscillations with dangerous high voltage spikes to improve the SMPS performance is established.Hence an optimal design of planar transformer is obtained.The final optimal simulation analysis results verify the correctness of above theoretical study.     

应用数字图像技术估测冬小麦冠层生物量垂直分布特征的研究

用数字图像技术研究了冬小麦冠层生物量的垂直分布。表明用一行小麦图像比多行小麦图像估测小麦生物量能更好地满足线性回归关系,估测效果更佳,以此为基础进一步研究了分层像素数估测小麦冠层分层现存生物量和有效生物量的方法。利用分层绿色像素数(LGPN)指标定性分析了不同栽培模式下冬小麦群体有效生物量的垂直分布和动态变化,并确定了基于图像特征的可用于定量分析的小麦群体垂直分布指数（I）。     

在干旱条件下保水剂保水效果及其对棉花产量的影响

研究在干旱条件下保水剂保水效果,及其对棉花产量和产量带来经济效益的影响。本次研究设5个处理,即土壤保水剂施用量为0 (CK)、15 (T1)、30 (T2)、45 (T3)和60 kg/hm² (T4),每个处理3个重复,在和田策勒县进行试验。结果表明：（1）各处理与对照的土壤含水量在0~30 cm的土层中差异不显著(P＞0.05),其中0~10 cm土层中各处理保持在14.62%~15.53%之间,10~30 cm保持在16.35%~17.95%之间;而在30~40 cm土层中,对照与各处理间的土壤中含水量差异明显(P＜0.05),T1、T2、T3和T4土壤含水量较CK分别增加了6.6%,7.45%,7.9%和7.8%。（2）相比CK,T1、T2、T3和T4产量达到显著差异水平(P＜0.05),籽棉产量最高为2868.90 kg/hm² (T2)。从经济效益分析可知,处理T1、T2、T3和T4分别比对照增加了6600.30、9649.80、6937.50、6543.45元/hm²,其中30 kg/hm² (T2)处理的投入产出比为16.08。试验区施用保水剂后土层土壤水分有增加的趋势,施用量在30 kg/hm²时棉花产量最高,此时经济效益也达到最高水平。     

基于数字图像的番茄黄化曲叶病毒病色彩分析研究

为实现番茄黄化曲叶病毒病的快速无损监测,利用计算机图像处理技术对番茄叶片图像进行研究。在3种颜色系统中比较9种颜色参数,发现其中5种色彩参数存在显著差异,通过进一步的分布统计研究,发现了各参数的最优区分区间。其中G、Y、Cb 3个值对感病叶片的区分率均达到70%以上,最优区分点分别在135、121和110,可以作为TYLCVD的特征参数应用于识别模型为后续研究识别模型提供重要的参数依据。试验结果表明,基于色彩分析法对番茄黄化曲叶病毒病进行识别是可行的。     

Modal parameters identification for short data sequences based on stratified sampling and optimism complex Morlet wavelet

A novel modal parameter identification method based on stratified sampling and optimism complex Morlet wavelet is proposed for short data sequences. Stratified sampling is applied to divide the structure response signal into different layers which called sub samples with different thresholds, and then free decrement response signal of each layer is extracted by random decrement technique. The optimism complex Morlet wavelet transform is applied to identify modal parameter of each layer, and the weight of the layer is also determined based on the sample standard deviation. The modal parameter of the structure can be obtained by weighted calculation.The engineering application shows that the proposed method has the ability to identify modal parameter accurately, decouple low frequency intensive modal composition and restrain high frequency fake modal effectively.     

客土基盘造林法对滨海盐渍土水盐动态的影响

为了使得客土基盘造林技术在滨海泥质盐碱地造林绿化应用中有充分的理论依据,以河北唐山市南堡开发区盐渍化土壤为研究对象,通过野外试验,研究了客土基盘造林法对滨海盐渍土水盐运移规律的影响,并比较了不同客土配比方式的排盐、降盐效果。结果表明,对照组（未经改造的原状土）土壤含水量变化规律与降水量变化规律相同或稍有滞后,处理组（以不同客土配比方式制作的客土基盘A1、A2、A3、A4）同样受降水规律的影响,但各土层含水量变化幅度差异较大,且峰值的出现时间不同,不同客土配比方式对0~20 cm、40~60 cm土层含水量影响具有显著性差异,对20~40 cm、60~80 cm影响无显著性差异。对照组含盐量变化与含水量变化存在显著负相关关系,观测结束时,返盐程度剧烈;而处理组则无显著相关关系,总体含盐量保持持续降低。4种不同客土配比方式对各土层含盐量变化影响具有显著性差异,平均含盐量均有大幅下降,总体降盐效果：A1>A3>A2>A4,植物根区含盐量下降效果：A1>A2>A4>A3。综合分析,以A1处理方式,即原状土与基质土以1:2配比制作的客土基盘排盐降盐效果最好。     

梨星毛虫性信息素的研究Ⅲ——性信息素分泌腺体形态结构的观察

采用扫描电镜及透射电镜技术对梨星毛虫成虫性信息素分泌腺体部位的外部形态及内部构造进行了研究。结果表明，该虫雌蛾性信息素分泌腺体是由两部分组成的。（１）翅部周缘上特化的深分叉的长鳞片；（２）腹部第３￣６节背、腹板的皮细胞层散生的腺体单位，是由腺细胞和间细胞组成。     

流固耦合的多元结构深厚覆盖层透水地基的力学特性

深厚覆盖层多元结构坝基在渗流过程中各土层力学差异明显,分析时关注的具体问题也不尽相同,需要深入研究。基于比奥固结理论,考虑土体的非线性流变以及土体固结变形过程中孔隙度、渗透系数、弹性模量及泊松比的变化;借助ADINA流固耦合模块来模拟西藏达嘎水电站坝基渗流场与应力场耦合过程,分析各层力学特性及相互作用。研究表明,透水性较强的表层土体是渗流主要通道,也是渗流进出区和沉降变形体现区,应在上游采取措施提高其压缩模量,下游区域增设反滤层和排水设施;坝基中的粉细砂层是坝基沉降的主要原因,对坝基沉降起主导作用,同时应注意其液化特性对坝基的不利影响;坝基中的承压含水土层对下游上部结构产生向上顶托力,若位置较深,则破坏性较小;坝基深部土层对整个坝基的渗流破坏影响较小,但对沉降和渗流量的影响不可忽视;表层砂卵砾石层和粉细砂层的渗透系数相差较小时,土层间不会发生接触冲刷。此外,还发现坝基孔隙水压力在快速衰减阶段被消散,期间土体固结较快。垂直防渗墙能有效降低渗透坡降和渗流量,将坝基沉降变形控制在防渗墙上游区域,但上游坝基变形对防渗墙产生较大的水平推力,应加大防渗墙尺寸或者采用辅助渗控措施。     

并流引风式远红外蔬菜脱水机的改进设计

现有的远红外蔬菜脱水机各层干燥箱均由同一台风机串流引风,因此各层箱体内的空气流量相等。针对这一问题,采用并流引风技术方案,将引风管从各层干燥箱同时引风,并且各连接管直径自上而下依次减小,从而使风机从各层干燥箱的引风量自上而下地相应减小,既可满足最上层干燥箱因物料水分蒸发速度快、风量需求大的要求,又可避免将下层接近干燥的、密度较小的物料吹起等现象的发生。