可靠性计算中加快蒙特卡罗仿真收敛速度的方法

针对电力系统概率分析中蒙特卡罗仿真效率不高的问题,考虑到大型发输电组合电力系统可靠性计算的特点,采用改进的控制变量法来减小样本方差,综合考虑了影响抽样结果准确性和计算速度的诸多因素,如系统风险水平、收敛判据、控制变量的选择以及参数选定等,并将评估范围由系统指标扩展到节点指标。在IEEE RTS系统的测试结果表明,所提算法严谨、实用,计算效果明显,具有良好的应用价值。     

一种新型设备用断路器——NDB3的结构原理及应用

介绍了液压-电磁式设备用断路器的工作原理、产品特点及其在典型行业中的应用,阐述了这一区别于传统热磁式断路器的优点,及在通信行业中的典型应用。     

炸药冲击波激励氩气闪光实验研究

建立了对可见光和近红外的瞬态测试记录系统。用实验方法研究了氩气在炸药冲击小励下产生的可见光光强。测得了不同压力下氩气的辐射强度,分析了气体压力对光强的影响。     

广州一中大坦沙校区规划设计

介绍在广州市第一中学规划建筑设计方案构思过程中,对人文精神、校园特色、历史记忆等理念的理解和贯彻。探讨针对高中新建校区对老校区校园文化的归属感和认同感营造的设计语言的运用。     

Neurotoxicity of Chronic Co-Exposure of Lead and Ionic Liquid in Common Carp: Synergistic or Antagonistic?

Previous studies have indicated that the harmful heavy metal lead (Pb) contamination in aquatic systems has caused intelligence development disorders and nervous system function abnormalities in juveniles due to the increased permeability of the blood–brain barrier. Ionic liquids (ILs) are considered “green” organic solvents that can replace traditional organic solvents. Studies have found the presence of ILs in soil and water due to chemical applications or unintentional leakage. Therefore, what would happen if Pb interacted with ILs in a body of water? Could ILs enable Pb to more easily cross the blood–brain barrier? Therefore, we examined the combined exposure of Pb and ILs in common carp at low concentration (18.3 mg L⁻¹ of Pb(CH₃COO)₂•3 H₂O and 11 mg L⁻¹ of the IL 1-methyl-3-octylimidazolium chloride, 5% of their LC₅₀) for 28 days in the present study. The result of a neurobehavioral assay showed that chronic exposure of lead at lower concentrations significantly altered fish movement and neurobehaviors, indicating that lead exposure caused neurotoxicity in the carp. Increases in the neurotransmitter dopamine levels and injuries in the fish brain accounted for neurobehavioral abnormalities induced by lead exposure. Moreover, we also found that lead could easily cross the blood–brain barrier and caused significant bioaccumulation in the brain. Particularly, our study indicated that the ionic liquid could not synergistically promote blood–brain barrier permeability and hence failed to increase the absorption of lead in the fish brain, suggesting that the combined exposure of lead and ILs was not a synergistic effect but antagonism to the neurotoxicity. The results of this study suggested that ILs could recede the Pb induced neurotoxicity in fish.     

邻苯二甲酸二烯丙基酯树脂固化特性的研究

运用示差扫描量热(DSC)法研究了邻苯二甲酸二烯丙基酯(DAP)树脂的固化反应历程。讨论了引发剂对DAP固化特性的影响,并由DSC曲线得到了DAP树脂的固化工艺和动力学参数。通过固化度、FT-IR的测试对DAP树脂在中温条件下的固化情况进行了研究。结果表明:在过氧化二异丙苯(DCP)固化体系中引入BPO可以使DAP树脂在更低温度下引发固化;在BPO、DCP用量均为2%的条件下,确定了体系的凝胶温度、固化温度、后处理温度分别为:100.5℃,124.3℃,137.8℃,表观活化能为129.3 kJ/mol,反应级数为0.950。固化度、FTIR的测试结果表明:DAP树脂在中温条件下可以固化得较完全。     

基于免疫否定选择算法的机场航班延误状态检测与实现

把免疫算法中的否定选择算法运用到航班延误状态的诊断检测与预测中,将生物免疫系统机制与机场航班运行机制联系起来,建立了相应的自体集合、检测细胞、抗原信息及它们之间的匹配模型,给出了检测方法。首先根据机场航班运行数据生成航班检测的成熟检测器和记忆检测器,然后用否定选择算法和航班数据对检测器进行训练和改进,最后利用检测器中的信息对机场航班状态分段进行预测,获得每个时段的航班延误状况,为机场有关部门对航班延误应急处理提供决策支持。仿真实验表明,该方法能较准确地预测航班的延误状态,且实时性好。     

Progressive Linear Precoder Optimization for MIMO Packet Retransmissions Exploiting Channel Covariance Information

This work investigates the design of linear precoders for ARQ packet retransmissions in multi-input multi-output (MIMO) systems. We consider transmitter precoder design based on partial MIMO channel information in the form of their covariance feedback. Our objective is to maximize the ergodic mutual information provided by multiple (re)transmissions of a packet subject to transmission power constraint. We propose a set of near-optimal successive linear ARQ precoders for flat fading MIMO channels. This progressive linear ARQ precoder combines the appropriate power loading and the reverse-order pairing of singular values in the current retransmission with previous transmissions. This reverse-order pairing is a special feature unique to our sequential ARQ preceding approach with demonstrated performance gains.