科创中国

Dual mechanical port machine(DMPM), as a novel electromechanical energy conversion device, has attracted widespread attention. DMPM with spoke type permanent magnet arrangements(STPM-DMPM), which is one of several types of DMPM, has been of interest recently. The unique coupling characteristics of STPM-DMPM are beneficial to improving system performance, but these same characteristics increase the difficulties of control. Now there has been little research about the control of STPM-DMPM, and this has hindered its practical application. Based on a mathematical model of STPM-DMPM, the coupling characteristics and the merits and demerits of such devices are analyzed as applied to a hybrid system. The control strategies for improving the disadvantages and for utilizing the advantage of coupling are researched. In order to weaken the interaction effect of torque outputs in the inner motor and the outer motor that results from coupling in STPM-DMPM, a decoupling control method based on equivalent current control is proposed, and independent torque control for the inner motor and outer motor is achieved. In order to solve address the problem of adequately utilization of coupling, minimizing the overall copper loss of the inner motor and the outer motor of STPM-DMPM is taken as the optimization objective for optimal control, and the purpose of utilizing the coupling adequately and reasonably is achieved. The verification tests of the proposed decoupling control and optimal control strategies are carried out on a prototype STPM-DMPM, and the experimental results show that the interaction effect of torque outputs in the inner motor and the outer motor can be markedly weakened through use of the control method. The overall copper loss of the inner motor and the outer motor can be markedly reduced through use of the optimal control method, while the power output remains unchanged. A breakthrough in the control problem of STPM-DMPM is accomplished by combining the control methods. Good performance in the control of STPM-DMPM will enhance its practicality, particularly as applied to hybrid systems.

The large and complex structures are divided into hundreds of thousands or millions degrees of freedom(DOF) when they are calculated which will spend a lot of time and the efficiency will be extremely low. The classical component modal synthesis method(CMSM) are used extensively, but for many structures in the engineering of high-rise buildings, aerospace systemic engineerings, marine oil platforms etc, a large amount of calculation is still needed. An improved hybrid interface substructural component modal synthesis method(HISCMSM) is proposed. The parametric model of the mistuned blisk is built by the improved HISCMSM. The double coordinating conditions of the displacement and the force are introduced to ensure the computational accuracy. Compared with the overall structure finite element model method(FEMM), the computational time is shortened by 23.86%–31.56% and the modal deviation is 0.002%–0.157% which meets the requirement of the computational accuracy. It is faster 4.46%–10.57% than the classical HISCMSM. So the improved HISCMSM is better than the classical HISCMSM and the overall structure FEMM. Meanwhile, the frequency and the modal shape are researched, considering the factors including rotational speed, gas temperature and geometry size. The strong localization phenomenon of the modal shape's the maximum displacement and the maximum stress is observed in the second frequency band and it is the most sensitive in the frequency veering. But the localization phenomenon is relatively weak in 1st and the 3d frequency band. The localization of the modal shape is more serious under the condition of the geometric dimensioning mistuned. An improved HISCMSM is proposed, the computational efficiency of the mistuned blisk can be increased observably by this method.

In working state, the dynamic performance of dry gas seal, generated by the rotating end face with spiral grooves, is determined by the open force of gas film and leakage flow rate. Generally, the open force and the leakage flow rate can be obtained by finite element method, computational fluid dynamics method and experimental measurement method. However, it will take much time to carry out the above measurements and calculations. In this paper, the approximate model of parallel grooves based on the narrow groove theory is used to establish the dynamic equations of the gas film for the purpose of obtaining the dynamic parameters of gas film. The nonlinear differential equations of gas film model are solved by Runge-Kutta method and shooting method. The numerical values of the pressure profiles, leakage flux and opening force on the seal surface are integrated, and then compared to experimental data for the reliability of the numerical simulation. The results show that the numerical simulation curves are in good agreement with experimental values. Furthermore, the opening force and the leakage flux are proved to be strongly correlated with the operating parameters. Then, the function-coupling method is introduced to analyze the numerical results to obtain the correlation formulae of the opening force and leakage flux respectively with the operating parameters, i.e., the inlet pressure and the rotating speed. This study intends to provide an effective way to predict the aerodynamic performance for designing and optimizing the groove styles in dry gas seal rapidly and accurately.

目的 分析肝小静脉闭塞病的临床特点、影像表现和诊治经验.方法 回顾性分析2005年1月~2011年1月我院收治的5例肝小静脉闭塞病患者的临床资料.结果 根据临床及病理学资料,将肝小静脉闭塞病分为急性期(1例)、亚急性期(1例)和慢性期(3例).CT平扫检查均发现肝脏肿大,肝实质密度降低.彩色B超检查均发现肝静脉变细,血流变缓;4例患者存在腹水.行门-体分流术3例,其中好转2例,死亡1例.行内科保守治疗2例,其中1例治愈,1例好转.结论 肝小静脉闭塞病临床表现以肝脏肿大和腹水为特征.影像学检查对肝小静脉闭塞病诊断有重要价值.急性期患者宜采取内科保守治疗,若出现门脉高压症状时,应行门-体分流术治疗.

随着人类社会的发展,人类活动在一定程度上影响了水文气象要素的变化,导致了干旱地区的扩大与干旱化程度的加重,这一趋势已成为全球关注的问题.在近年我国干旱灾害频繁发生的背景下,分析了河北省农业旱灾特点和发展趋势,研究了其严重危害,根据河北省农业实际提出了应对策略,为进一步应对干旱发生、抗旱减灾、确保农业生产、确保粮食安全具有重要的指导作用.

采用废旧聚乙烯(PE)与硫酸钙晶须为原料,通过熔融挤出共混制得废旧PE/硫酸钙晶须复合材料,比较了经硅烷偶联剂KH-590改性与未改性的硫酸钙晶须用量对废旧PE/硫酸钙晶须复合材料力学性能的影响,分析硫酸钙晶须增强度旧PE的机理和废旧PE/硫酸钙晶须复合材料的微观结构.结果表明:当硫酸钙晶须用量为15%时,未改性硫酸钙晶须使复合材料的拉伸强度、冲击强度提高了23.1%、9.1%;改性硫酸钙晶须使复合材料的拉伸强度、冲击强度、弯曲强度提高了26.7%、15.6%和5 3%,其在废旧PE中分布均匀,能起到明显的增强作用.

采用不同偶联剂对纳米碳化硅进行表面处理后,制备了聚四氟乙烯/纳米碳化硅复合材料,考察了偶联剂种类和含量随载荷变化对复合材料摩擦磨损性能的影响,并利用扫描电子显微镜观察和分析了复合材料磨损表面形貌及其磨损机理.结果表明,经表面处理的纳米碳化硅填充后的复合材料硬度和摩擦磨损性能均有提高,以钛酸酯偶联剂(NDZ101)处理效果最好;随着偶联剂含量的增大,钛酸酯偶联剂(NDZ101)处理的复合材料的磨损量和摩擦因数均增大,偶联剂最佳含量为填料质量的1%;偶联剂处理后的纳米碳化硅与基体之间形成了良好的界面,复合材料的磨损以黏着磨损和磨粒磨损为主.

为了了解和掌握承德市水化学特征,采用统计学分析方法、阿廖金分类法和舒卡列夫分类法对承德市地表水、浅层地下水水化学特征进行了分析.结果表明,承德市地表水中的矿化度、总硬度、Ca^2+、HCO3^-和浅层地下水中的HC03一这些指标的变异系数小于30%,离散程度小,含量比较稳定,地表水中HCO3^-和浅层地下水中的Cl^-、SO4^2-、CO3^2-这些指标变异系数大于90%,离散程度大,稳定性较差;地表水的总硬度及矿化度随地理分布存在定的规律,从西北到南部,总硬度和矿化度的值由低到高分布;承德市地表水和浅层地下水的主要阴阳离子构成基本一致,阳离子以Ca^2+、Mg2+为主,阴离子以HC03一为主.分析原因,沿河打井取水,是承德山区取用浅层地下水的主要方式,地表水是浅层地下水的主要补给来源,两者之间没有一个明显的界限.

河北省引黄输水工程是解决河北省水资源危机的有效措施.从1993年开始的引黄输水工程,为缓解河北省水资源紧张发挥了重要作用.通过对引黄输水水质监测结果分析,通过对8次引黄输水水质评价,在对所监测的项目中.有3次输水没有超标现象,有3次污染物的超标倍数小于或等于1,有2次超标倍数在1.2~2.8之间.从输水水质主要污染物分析,主要污染物为氨氮、挥发酚、总磷、总锰、总镉.根据对黄河水源水质资料分析,氮类污染和金属类污染主要受缓和黄河水源的影响,挥发酚、总磷污染主要受河道环境的污染.通过对引黄调水水质评价,受黄河水源和沿途河道的影响,引黄调水水质存在较大的不确定性.因此应加强对引黄调水水质的监测,为用水部门及时提供调水水质信息,以便制宰相席的用水方案.