Thermal hydraulic behaviors during loss of RHR system at mid-loop operation of Chinese 300 MWe PWR NPP

Thermal hydraulic behavior of nuclear power plant (NPP) is analyzed by using mechanistic computer code for loss of residual heat removal (RHR) system during mid-loop operation of Chinese 300 MWe two-loop pressurized water reactor is presented. In the absence of recovery of RHR or other accident management measures, the reactor core will be uncovered for a long term resulting in core heat-up, degradation and relocation to the lower plenum. The effectiveness of available mitigate measures, such as safety injection system, gravity feed from refueling water storage tank (RWST) and steam generator (SG) reflux-condensation, are investigated. Coolant injection is highly effective in halting the accident progression and make the core recovered. The cooling capability of SG reflux-condensation has a relationship with different availabilities of steam generators and decay heat power. 6 days after shutdown, 2SG operation can keep the water level at mid-line of hot leg. 12 days after shutdown, both 2SG operation and 1SG operation can keep the water level at mid-line of hot leg. The analyses also indicate that the cooling mechanism of safety injection system is more effective than gravity feed from RWST and SG reflux-condensation. Through confirming the success criteria of SG reflux-condensation, time windows can be devided. Then, event trees for loss of RHR system under mid-loop operation are built with considering the analysis results and abnormal procedure.     

H∞技术在高速液压控制系统中的应用研究

采用高性能的TMS320LF2407DSP芯片为主处理器,针对非线性特性的液压伺服系统,利用H∞控制技术设计了一种高性能液压控制器,开发出一套新的液压伺服控制系统。同时利用H∞控制器在参数摄动的条件下具有更快的响应和更小的超调,提高了系统的稳定性和快速性,并为DSP在自控领域的实时控制提供了参考依据,得出H∞控制器具有很强鲁棒性的结论。     

Effect of dietary selenium on the progression of heart failure in the ageing spontaneously hypertensive rat

Oxidative stress has been directly implicated in hypertension and myocardial remodelling, two pathologies fundamental to the development of chronic heart failure. Selenium (Se) can act directly and indirectly as an antioxidant and a lowered Se status leads to a higher risk of cardiovascular disease. This study examined the role of Se on the development of hypertension and subsequent progression to chronic heart failure in spontaneously hypertensive rats (SHR). Three dietary groups were studied: (i) Se‐free; (ii) normal Se (50 μg Se/kg food); and (iii) high Se (1000 μg Se/kg food). Systolic blood pressure and echocardiography were used to detect cardiac changes in vivo. At study end, cardiac tissues were assayed for glutathione peroxidase activity, thioredoxin reductase activity, and protein carbonyls. The major finding of this study was the high heart failure‐related mortality rate in SHRs fed an Se‐free diet (70%). Normal and high levels of dietary Se resulted in higher survival rates of 78 and 100%, respectively. Furthermore, high dietary Se was clearly associated with lower levels of cardiac oxidative damage and increased antioxidant expression, as well as a reduction in disease severity and mortality in the SHR.     

气动精密减压阀开发现状及研究方法探讨

简要介绍了精密减压阀的开发现状及研究方向。阐述了减压阀的基本特性和国内外的重点产品及关键技术,继而提出精密减压阀在精度、灵敏性、稳定性和材料等方面的改进需求,最后对精密减压阀的通用研究方法进行了探讨。     

Physiological compliance and team performance

Physiological compliance (PC) refers to the correlation between physiological measures of team members over time. The goals of this study were to examine ways of measuring PC in heart rate variability (HRV) data and the relationship between PC and team performance. Teams were tasked with entering both real and simulated rooms and “shooting” individuals with a weapon and identifying individuals without a weapon. The linear correlation and directional agreement PC methods were shown to be the most sensitive to differences in performance, with greater PC being associated with better performance. The correlation method when applied to a measure of respiratory sinus arrhythmia (RSA) revealed a significant difference between high and low performers (t[8] = −2.31, p = 0.03) and the directional agreement applied to inter-beat-intervals and RSA revealed trend-level differences (t[4.62] = −1.86, p = 0.06 and t[8] = −1.68, p = 0.07). These results suggest that PC may have merit for predicting team performance.     

Social psychophysiological compliance in a four-person research team

A continuous, non-invasive and objective measure of teamwork effectiveness could be very useful to the human factors design community. Social psychophysiological compliance (SPC), estimated by scoring the extent that heart rate variation was synchronous across team members, was explored as a predictor of teamwork effectiveness during 20 real planning meetings over a 6-month period. Speech activity and heart rate variability of all four (2 male, 2 female) team members were continuously monitored. Exploratory analyses tested if team member ratings of various aspects of teamwork effectiveness were predicted by SPC scored (1) over whole meetings, (2) during one team member's speech, (3) during periods in which two team members spoke in sequence or (4) over 30-s periods and averaging highest values. SPC during periods of sequential speech negatively predicted team members' ratings of Team productivity, Quality of communication, and Ability to work together. SPC shows potential as an objective, non-invasive means to monitor teamwork effectiveness but this relationship warrants further investigation and replication before use in ergonomics applications.     

当代城市文化背景下的城市功能再生——另一种生态建筑

本文从现代城市文化的角度着手深入探讨了影响城市功能再生的诸多深层社会因素，指出城市功能的再生便是城市文化的再生，城市文化的再生便是城市人文精神的重塑，建筑学意义上的现代城市人文的重塑便是现代城市人对自身生存空间的心理归属，指出存在于现代建筑空间中的另一种生态体系——心理生态，进而提出基于非物质基础上的另一种生态建筑概念.     

秦山核电厂安全壳系统B、C类密封性试验

叙述了秦山核电厂安全壳系统B、C类密封性能试验概况,主要包括试验范围、泄漏率分配、试验结果和总体评价等。     

汽车空调PSX-A制冷系统

汽车空调,由于车速的变化,车室内冷量会随车速变动而波动,尤其是高速或怠速时,能否稳定室内的温度是世界各国极为关注的课题。为此,本文提出一种汽车空调制冷系统,即 PSX—A制冷系统。该系统能解决上述难题,其在各种车速改变的情况下,能自动保持车室内冷量的恒定,达到车室恒温。PSX—A制冷系统,比美 CCOT [Cycling Clutch OrifriceTube]。M—5斜板式压缩机能量控制,VIR部件[Valves—In—Receives]等系统适应范围更广,系统筒单,性能优越,成本低,维修调试方便,是行之有效的系统。