Mechanical properties of high-strength concrete after fire

With compressive strength grade of C40, C60, and C70, respectively, normal-strength concrete (NSC) and high-strength concrete (HSC) were used to investigate compressive strength, splitting tensile strength, and bending strength after high temperature. The oil furnace is used in this study. Its temperature-time curve is close to standard curve, which conforms to Chinese standard GB/T 9978-1999. After being heated to temperatures of 200, 400, 600, 800, and 1000 °C, respectively, the mechanical properties of HSC were tested. The influence of temperature, water content, specimen size, strength grade, and temperature profiles on mechanical properties of HSC are discussed.     

堆场疏浚泥颗粒分选特性初步量化方法

为了准确评估堆场存储能力和合理选择疏浚泥处理工艺,以泥沙运动学为理论基础,将疏浚泥颗粒分为d0.005 mm、0.005 mm≤d≤0.01 mm和d0.01 mm 3个粒组,分析了各粒组相对含量的沿程变化规律,明确了堆场疏浚泥分选的主要原因是d0.01 mm粒组与0.005 mm≤d≤0.01 mm粒组的相对运动;以分选系数量化堆场疏浚泥分选的显著程度,以偏离系数量化原泥颗粒组成对堆场疏浚泥分选的影响,分析了分选系数、偏离系数分布与堆场疏浚泥土性分布的关系,提出了堆场疏浚泥分选特性的初步量化方法。研究结果表明:随着离吹填口距离的增大,分选系数沿程减小,呈幂函数分布,堆场疏浚泥分选性沿程减弱,吹填口附近分选系数最大,颗粒分选显著,粒度差异大,退水口附近分选系数趋近于零,分选不明显,颗粒分布均匀;偏离系数沿程先减小后增大,呈勺形分布,反映堆场前、后段疏浚泥土性与原泥相差较大,而堆场中段疏浚泥土性与原泥接近;分选系数、偏离系数的沿程分布与堆场疏浚泥土性分区具有良好的相关性。     

Differential geometry based active fault tolerant control for aircraft

This work shows how to use a differential geometry tool to design a novel nonlinear active fault tolerant flight control system for aircraft. The proposed control scheme consists of two main subsystems: a controller, which is designed for the nominal plant, and a fault detection and diagnosis module, which provides fault estimation. A further feedback loop exploits the fault estimation to accommodate faults affecting the system. The estimate convergence and the stability of the active fault tolerant flight controller are theoretically proved. Finally, high fidelity simulations show the effectiveness of the scheme.     

ITS无线接入网业务建模和调度方法设计

首先介绍了面向智能交通系统(Intelligent Transportation System,ITS)的无线接入网网络结构和主要业务,对车路协同业务和PTT语音业务进行了分析和建模。然后根据不同业务的特点及QoS需求提出具有针对性的调度方案:对于车路协同业务,采用适应车速的动态调度方法;对于PTT语音业务,采用基于状态转换的调度方法;对于视频和其他对时延不敏感的数据业务,采用缓存请求的调度方式。最后在OPNET平台上对调度方法进行仿真,针对各种ITS业务得出延时、丢包率等性能曲线,验证了算法的有效性,这也为ITS接入网的网络设计提供了参考。     

基于概率支持向量回归的产品设计时间预测模型

为使产品设计时间预测既克服小样本、异方差噪声问题,又提供除预测值以外的其他有用信息,建立概率支持向量回归(PSVR)模型。首先,在异方差回归模型基础上设计概率约束条件,以使预测值以较大概率位于真实值的某邻域,结合具有参数不敏感损失函数的支持向量回归确定优化目标,提出PSVR。然后,将最大完工时间知识嵌入进PSVR的约束条件,用以确定真实值邻域的宽度,将交叉验证与遗传算法相结合以确定PSVR的相关参数。最后,以注塑模具设计的实例进行分析,结果表明基于PSVR的时间预测方法可同时提供有效的预测值和预测区间。     

臭氧-生物活性炭工艺处理黄浦江微污染原水的中试研究

以黄浦江原水为研究对象,对臭氧-生物活性炭（O3-BAC）组合工艺去除有机污染物的性能、机理进行了中试研究。结果表明,该工艺对各指标的去除率为：CODMn 24%,UV25435%,三卤甲烷前体物31%,AOC 63%,且对各分子量区间的有机物的去除有互补性。O3-BAC组合工艺一方面可以有效去除黄浦江原水中的微量有机污染物、消毒副产物前体物,减少后加氯量,降低消毒副产物生成量,保障饮用水的化学安全性;另一方面能明显降低水中的可同化有机碳（AOC）浓度,提高饮用水的生物稳定性。     

Dielectric and pyroelectric characteristics of the infrared sensitive (Pb1?xSrx)TiO3 ceramics

PST ferroelectric ceramics were fabricated successfully by a two-step method, i e first, PbTiO₃ and SrTiO₃ were sintered respectively, then mixed and sintered together. The process and characteristics of PST ferroelectric ceramics were introduced and researched. Their dielectric and pyroelectric characteristics are as follows dielectric constant 10⁴ order, low dielectric loss (lower than 3.0% in the working frequency range of 1–1 000 kHz), saturation polarization intensity 10⁻¹ C/m² order, and pyroelectric coefficient 10⁻³ C/m²·K order.     

信号交叉口影响区路边停车的交通流延误模型

为了提高路边停车带的利用率和减小其对路段交通流的影响,以城市一幅路为研究对象,从分析路边停车带的车辆驶出、汇入时对道路动态交通流的影响入手,考虑路边停放车辆及信号控制的共同作用,运用稳态理论分析车辆在信号交叉口的延误时间,建立了停车带第i个泊位车辆驶出影响下,单位时间内机动车流在信号交叉口的延误-Di与停车带离开停车线的距离L0、路段交通流量以及信号周期时长C和红灯时间r的关系模型.以南京市天津路路边停车带为例,重点分析了距离交叉口停车线最近停车位的车辆驶出引起的延误时间-D1随L0、信号周期时长C、红灯时间r变化的规律,结果表明,随着交叉口饱和流率的不同,停车带与交叉口的距离可分别在60m和90m区间设定,而交叉口信号周期长度和红灯时间比例均对延误结果存在显著影响.     

Fault location for parallel transmission lines using one-terminal current traveling waves

With proper phase module transformation,parallel lines can be decomposed to the same directional net and the reverse directional net. The propagation characteristics of traveling waves in the reverse directional net were analyzed,and the refraction coefficient at the fault point for a single phase fault was derived. In addition,the module selection was discussed. Simulation results show that satisfying accuracy can be achieved with the proposed method. Moreover,it is immune to fault types,fault resistances,and outside system parameters.