柴河电厂设备运行状态显示仪的研制和使用

柴河电厂研制和使用了设备运行状态显示仪,将各种设备的运行状态集中显示在中央控制室,运用设备运行状态显示仪,提高了故障(或事故)的处理速度,为实现微机自动化管理作了前期工作。     

Dynamic expression of matrix metalloproteinases (MMP-2, -9 and -14) and the tissue inhibitors of MMPs (TIMP-1, -2 and -3) at the implantation site during tubal pregnancy

Matrix metalloproteinases (MMPs) are responsible for extracellular matrix (ECM) degradation, and their functions are regulated by tissue inhibitors of MMPs (TIMPs). The evidence for the roles of MMPs and TIMPs in implantation and placentation has remained insufficient in humans, especially during the early stages. Tubal pregnancy has some similarities to normal intrauterine pregnancy and therefore may provide a unique model for implantation studies. In the present study, the expression of MMP-2, -9 and -14, and TIMP-1, -2 and -3 at the feto-maternal interface during tubal pregnancy was examined by immunohistochemistry and in situ hybridization. We found that MMP-9 and TIMP-1, -2 and -3 are produced by all types of extravillous cytotrophoblast (EVCT) cells, while MMP-2 and -14 mainly exist in distal column cytotrophoblast (CCT) cells and invasive EVCT cells. Meanwhile, the intensity of MMP-14 and TIMP-1 and -2 increased along the invasive pathway toward maternal interstitium. In addition, MMP-2, -9 and -14 and TIMP-1, -2 and -3 were all detected in the villous CT (VCT) cells. Furthermore, both the mRNA level and immunoreactivity of MMP-9, TIMP-1 and -3 increased, while those of TIMP-2 decreased concurrent with the progression of pregnancy during weeks 3-9. The unique expression pattern of various MMPs and TIMPs at the feto-maternal interface suggests that they may have roles in regulating the controlled invasion of trophoblasts during implantation and placentation. Meanwhile, the study provides a better understanding of the mechanisms involved in cellular events during human pregnancy, especially at the initiation stage of implantation.     

跨电压等级不接地故障时低电压系统的过电压评估

发生跨电压等级不接地故障时,低电压等级系统出现电压升高的特征变异.针对这个问题,建立了跨电压等级不接地故障的模型,以此为基础探究各关键运行与设计参数对低电压等级系统过电压的影响,并在实际电网中对过电压倍数进行数值评估.研究表明,跨电压等级单相不接地故障时,低电压等级系统过电压情形最严重,此过电压倍数与高电压等级系统电源强度呈正相关,与低电压等级系统电源强度呈负相关;同塔架设位置对过电压倍数影响大,线间互感对过电压倍数影响小.综合以上规律,给出系统安全运行方面的建议.     

Numerical Modeling of a New Flight Simulator Enabling Continuous 360-Degree Spinning and Translational Motion

一种新型可实现360°旋转和平动的飞行模拟器的数值模拟

周跃发¹,李涛¹,毕再林¹,周文博²,陈群凯¹,张治勇1

（1.哈尔滨工程大学 航天与建筑工程学院,哈尔滨 150001;

2.伦敦大学学院 心血管工程实验室,英国）

摘要：

本文提出一种新型的飞行模拟器,介绍了基于逆运动学方法和Newton-Euler方法的模型,对模拟器的运动学和动力学进行理论分析,并在Simulink平台上进行仿真分析。理论和仿真结果表明,该飞行模拟器不仅可以实现六自由度运动,而且座舱可以实现360度空间旋转,在较大程度上恢复了飞机在空中飞行的复杂运动。飞行模拟器有助于飞行员在实验室获得更好的训练,本文的研究成果对飞行模拟器的设计和分析有一定的参考价值。

关键词：三轴转台;多自由度;飞行模拟器;牛顿-欧拉方程;数值模拟

     

Characteristic analysis of the isokinetic strength in lower limbs of the elderly on training for postural control

The principal objective of this study was to assess the characteristic of muscular strength in the lower limbs of elderly subjects after 8 weeks of postural control training with a postural control training system designed specifically for the elderly. In order to verify the characteristic of muscular strength in the lower limbs, 15 elderly volunteers (training group, TG) took part in a balance training regimen using the postural control training system. An additional 15 elderly volunteers (control group, CG), who were employed as the control group, were also tested for comparison with the training group. To evaluate the effects of the training and the characteristic of the muscular strength, we measured the relevant parameters, such as the sway path and the sway area of center of pressure under different visual conditions and the concentric isokinetic strength of the joints in the lower limbs prior to, during, and after training. In this study, we hypothesized that the participants would evidence better balance control, i.e. smaller postural sway and greater concentric isokinetic strength of the ankle and knee joints, than those who did not participate in the training program. We also assessed the relationship of the COP sway area and the concentric isokinetic strength of the ankle, knee, and hip joints of the elderly subjects. The results demonstrated that the correlation between isokinetic strength of the ankle and knee joints and the postural stability dropped significantly in a negative-linear fashion. However, no significant difference was noted between the concentric isokinetic strength of the hip joint and the postural stability of the subjects. The concentric isokinetic strength of the ankle and knee joints was found to be more relevant to the movement of the lower limbs, which is important in terms of the postural strategy. Via these results, we confirmed the characteristics of muscular strength in the lower limbs of the elderly and the relationship between muscular strength and postural stability. Therefore, the elderly that is reinforced muscular strength of the joints of lower limbs can perform increased postural training capability.     

金属小目标对电容近炸引信电极电容的影响

利用导体之间感应系数与自电容、互电容之间关系，从理论上论述了金属小目标靠近电容近炸引信电极时自电容和互电容的变化规律，并且根据有限元计算的方法验证了推导的结论。     

基于改进EEMD-SE-ARMA的超短期风功率组合预测模型

针对风力发电功率时间序列具有非线性和非平稳性的特性,提出了一种改进的集成经验模态分解(Modified Ensemble Empirical Mode Decomposition,MEEMD)-样本熵(Sample Entropy,SE)-ARMA的风电功率超短期组合预测模型。将EEMD分解中添加的白噪声信号改为添加绝对值相等的正负两组白噪声信号,并将MEEMD分解过程中的EMD步骤使用端点延拓和分段三次埃尔米特插值进行改进,形成一种改进的EEMD分解算法(即MEEMD)。利用MEEMD-SE将风力发电功率时间序列分解为一系列复杂度差异明显的风电子序列;针对每一个不同的子序列建立适当的ARMA预测模型;将各预测分量进行叠加重构,得到最终的风电功率预测值。通过算例分析及与其他几种预测模型预测结果的对比,证明MEEMD-SE-ARMA组合预测模型可以有效地提高风力发电功率超短期预测的精度。     

陶瓷挤出和喷射增材制造技术研究进展

增材制造技术被认为是解决复杂结构陶瓷零部件制造的有效新途径之一.其由点-线-面-体累加成型的制造过程还为具有特殊宏微观结构的陶瓷零部件赋予了一体化的结构功能特性.综述了熔融沉积造型、挤出直写、喷墨打印以及粘接剂喷射等四种基于挤出或喷射成型原理的陶瓷增材制造技术的历史起源、工作原理、原材料制备以及打印工艺研究等内容,并结合研究实例探讨打印件性能与应用研究.通过不同技术的特点对比,提出目前陶瓷挤出喷射增材制造技术面临的主要挑战并进行了展望.     

Optimization on the Crosswind Stability of Trains Using Neural Network Surrogate Model

Under the influence of crosswinds,the running safety of trains will decrease sharply,so it is necessary to optimize the suspension parameters of trains.This paper studies the dynamic performance of high-speed trains under cross-wind conditions,and optimizes the running safety of train.A computational fluid dynamics simulation was used to determine the aerodynamic loads and moments experienced by a train.A series of dynamic models of a train,with different dynamic parameters were constructed,and analyzed,with safety metrics for these being determined.Finally,a surrogate model was built and an optimization algorithm was used upon this surrogate model,to find the mini-mum possible values for:derailment coefficient,vertical wheel-rail contact force,wheel load reduction ratio,wheel lateral force and overturning coefficient.There were 9 design variables,all associated with the dynamic parameters of the bogie.When the train was running with the speed of 350 km/h,under a crosswind speed of 15 m/s,the bench-mark dynamic model performed poorly.The derailment coefficient was 1.31.The vertical wheel-rail contact force was 133.30 kN.The wheel load reduction rate was 0.643.The wheel lateral force was 85.67 kN,and the overturning coef-ficient was 0.425.After optimization,under the same running conditions,the metrics of the train were 0.268,100.44 kN,0.474,34.36 kN,and 0.421,respectively.This paper show that by combining train aerodynamics,vehicle system dynamics and many-objective optimization theory,a train's stability can be more comprehensively analyzed,with more safety metrics being considered.