一种面向对象体系结构的度量模型

针对面向对象体系结构的软件系统缺乏有效度量方法的现状,通过行为、逻辑、构件和部署4个互为补充的模型,对面向对象的软件进行了架构分析,并确定了度量数据的采集集合.基于架构分析获得的原始系统数据,吸收快速原型与白盒、黑盒的基本原理,作者提出了一种适合面向确定对象系统的功能-结构-原型度量模型FCPMM(Function Configuration Prototype Metric Model).结合面向对象的基本准则与基本遗传算法,导出了该模型的循环收敛算法,从而可动态求解软件系统的最优状态.最后利用Matlab仿真实例,从度量参数适应度和最佳个体解码值两个方面验证了该算法的可行性.     

基于湍流自旋理论的二维方腔旋转流动的数值模拟

基于湍流自旋理论对旋转方腔内不可压流体的流动进行了二维数值模拟,用有限容积法在交叉网格上对控制方程进行离散,采用SIMPLEC算法进行计算,对流项的离散方面采用了延迟修正的QUICK格式,最后采用二维的TDMA算法进行迭代求解,并对边界条件处理采用了Block块技术.同时与经典理论即Navier-Stokes（N-S）方程的模拟情况做了比较.得出下列结论：N-S方程表明方腔旋转时内部流体只会作刚体旋转;而自旋模型表明该类流动具有不平凡性和不稳定性：即流体的内聚力不足以使流体跟随固体边界作刚体运动,旋转边界必然在流体中诱导出小尺度耗散涡旋,这些小尺度涡旋在固壁附近组织出正负相间的拓扑缺陷（涡旋场强）,这一流体定向奇性会与速度场耦合,并容易形成复杂的大尺度的涡旋运动.     

锡崖沟瀑布景观工程水力模型试验研究

根据锡崖沟景区规划设计,沿锡崖沟水库溢洪道下部开凿底洞引水,在水库下游红岩大峡谷常年形成20 m宽大瀑布.以满足瀑布流的重力和紊动阻力相似的原则进行了其正态模型设计.通过模型放水试验表明：流量变化对瀑布水流流态影响很大,溢流槽空间狭小,加之上游进口扇形扩散段扩散角偏大,水流扩散不充分,堰顶溢流不均匀,瀑布景观效果差.将模型的溢流堰顶修改为T型复式断面后,顺应了水流的流动特性,在各级流量下均能获得比较好的瀑布景观效果.     

低雷诺数气液交叉流装置研究（I）——孔流液柱流动特性数值模拟

针对低雷诺数的气液交叉流气体净化过程,提出有效避免二次雾沫夹带的液柱流体力学条件。数值模拟结果表明,液柱表面随着离开孔口的距离而变化,采用公式Lb／d=2．84We^0.694能有效预测液柱的断裂行为。     

管板和传热管胀接应力应变的数值模拟及分析

蒸汽发生器是核电厂一回路与二回路的枢纽,传热管和管板的连接处为事故多发区,而机械加工过程残留的应力是引起裂纹的主要原因.应用有限元软件对某型蒸汽发生器中的传热管和管板的胀接过程进行瞬态模拟,得到不同胀接压力下的管板和传热管的残余应力和残余应变值,为传热管和管板最佳胀接参数的确定以及工作过程中应力腐蚀的预防提供理论依据.研究结果标明,管板孔表面的残余径向应力和残余径向应变值都是随胀接压力的增加而增加,且沿着轴向的变化规律相似.     

微小型工业汽轮机智能交流伺服调节系统研究

为了解决微小型工业汽轮机组调节控制系统设备简陋,动态响应和稳态精确度差的问题,提出了一种采用交流伺服电机和模糊PID控制的自动调节系统．在对调节系统部件特性数据进行分析的基础上,应用机理分析法建立了工业汽轮机交流伺服调节系统的数学模型,建立了以模糊PID控制和常规PID为主的控制器仿真模型,并利用MATLAB（SIMULINK）进行了动态仿真．结果表明,采用交流伺服电机作为执行器比传统的机械式调节系统具有更优良的动态和稳态性;采用模糊PID控制策略的调节系统在减少调节时间、改善动态品质方面均好于常规PID调节器．为工业汽轮机交流伺服调节系统的进一步研究提供了理论基础．     

水电站月度调度函数的模型制定与模拟结果评价

基于统计学中多元逐步回归原理建立了多年调节水电站分月调度函数模型,并根据水电站优化调度特征确定待选自变量,用以指导电站实际优化调度运行。在考虑电站自身各约束及综合利用要求的前提下,进一步采用程序设计模拟调度函数指导水电站长系列调度运行,通过对模拟结果的全面评价,证实所建立的调度函数具有良好的指导意义和实用价值。     

基于有限体积法的G4-73型离心风机三维流场数值模拟

基于有限体积法,利用Fluent软件对G4-73型离心风机内部流场进行了全三维数值模拟。结果表明:蜗壳内的低能流体区沿轴向朝流动方向推进;叶轮内的静压和动压在叶片吸力面靠近叶轮进口处最低,叶轮流道中动压等值线呈"凸"型分布,在叶片压力面靠近叶轮出口处静压和动压达到最大值,且叶轮出口相对总压损失集中在吸力面和前盘侧。     

Root growth and phosphorus and potassium uptake by two corn genotypes in the field

In a field study P and K uptake by two corn (Zea mays L.) genotypes which differed in root growth was investigated. The effect of differences in root growth on P and K uptake was assessed using a mechanistic-mathematical model which describes nutrient uptake by growing plant roots in soil. Nitrogen was applied at 0 and 227 kg ha^–1 to Pioneer 3732 and B73xMo17 corn grown on Raub silt loam (fine-silty, mixed, mesic Aquic Argiudoll) and at 227 kg N ha^–1 to these two genotypes on Chalmers silt loam (finesilty, mixed, mesic, Typic Haplaquoll). Root growth and P and K uptake by the two corn genotypes was measured 31, 47, 75 and 91 d after planting on the Raub and 31, 47, 61 and 75 d after planting on the Chalmers soil.Root growth and P and K uptake by B73xMo17 was greater than that of Pioneer 3732 on N-fertilized Raub soil. On Chalmers soil the difference in root growth between the two genotypes resulted in an increase in K but not P uptake. The higher soil P level of the Chalmers appears to have offset possible differences in P uptake due to root size. There were no differences between the two genotypes in either the percentage of roots with root hairs, or the density or length of root hairs. Phosphorus and K uptake calculated with the simulation models for both corn genotypes on both soils over each of three growth periods agreed with observed P (Y = 0.68X + 1.71; r = 0.944^**) and K (Y = 0.88X + 15.52; r = 0.928^**) uptake. Differences in P and K uptake between B73xMo17 and Pioneer 3732 resulted primarily from the difference in root growth in the topsoil. A high correlation was found between root surface area and P (r = 0.893^**) and K (r = 0.928^**) uptake by both corn genotypes on both the soils.Journal paper No. 10,316 Purdue Univ. Agric. Exp. Stn., W. Lafayette, In 47906. Contribution from the Dep. of Agron. This paper was supported in part by a grant from the Tennessee Valley Authority.     

A Thermo-Mechanical Study of Some Epoxy Adhesives Subjected to Combined Dynamic and Static Stresses

The object of the present study was to investigate the effect of superimposed dynamic and static stresses on mechanical and thermal properties of some epoxy adhesives. It was found that combinations of shear creep and torsional oscillations, applied simultaneously to adhesive joints at temperatures within the glassy range of the adhesive, led to strengthening of the joints in shear and to an increase in the glass transition temperature of the adhesive. Similar loading stresses applied at temperatures close to the T_g of the adhesive, led to opposite effects on the above mentioned properties of the joints. The width of the glassy-rubbery transition of the adhesives increased, in the whole range of temperatures used in this study and for all epoxy compositions, as a result of subjecting the joints to superimposed dynamic and static stresses. The broadening of the glass transition was interpreted as a result of the stiffening of polymer network during the combined stressing experiments. A linear relationship was found between the area of endothermal peaks in the first DSC scan of specimens subjected prior to test to superimposed dynamic and static stresses at temperatures below T_g, and the shear strength of the joints. In agreement with this observation and with literature data, a linear relationship was revealed also between the glass transition temperature of the resins (measured in the first DSC scan) and the shear strength of the joints. Based on experimental observations and on some literature information, it was suggested that the strengthening of the joint, as well as the changes in thermal properties of the adhesives, are mainly due to physical processes, such as short-range orientation of network chains and an increase in intermolecular interaction between highly polar sites of the network. The possibility that superimposed stressing led to changes in chemical crosslinking was discussed but it seems that no such reactions occurred.