空间-功能-社会:古城保护的三维解读——以江苏省苏州市为例

与我国其他古城一样,苏州古城经历了新与旧、传统与现代、保护与发展的多重考验,也面临更大的发展机遇。而古城保护的内涵比较复杂,不仅是一个空间现象,而且是一个复杂的经济化、社会化过程,不能以牺牲弱势群体的利益为代价,必须与社会和谐相辅相成。从空间维度、功能维度以及社会维度解读苏州的古城保护,有助于全面理解古城保护事业。     

水平衡测试中耗水量测试与计算方法探讨

耗水量的计算是水平衡测试的一项重要内容,也是难点。通过水平衡测试实践总结出耗水量的几种计算方法,对水平衡测试过程中正确计算耗水量具有一定的指导意义。     

一种面向任务优化的多核心星务管理系统设计

为进一步提升小卫星的数据处理能力,对星载电子系统进行了优化设计.在现有可重构星务管理系统的基础上,提出一种多核心处理器星务管理系统设计方法.结合多核心处理器特点,按照硬件资源以及任务模式对星务管理系统的传统任务划分方法进行优化,将单一处理器任务集中处理的模式分解为主、协处理器双核任务处理模式.与哈尔滨工业大学试验卫星三号星载计算机的功能对比表明,多核心可重构星务管理系统在运算速度、控制计算精度方面优于传统的星务管理系统处理方式,有能力替代现有的星载计算机成为未来微型航天器的核心.     

基于Hilbert变换的单边带调制系统及FPGA实现

为解决单边带调制方法因在载波调制技术中难以实现而不被广泛应用的问题,对单边带调制方法进行了研究,提出了基于Hilbert正交变换的单边带调制算法,以及该算法的FPGA（Field Programmable Gate Arrays）实现。建立了Matlab的系统分析模型,采用DSP Builder设计了单边带调制程序,并通过Modelsim对该程序进行了仿真,得到了理想的单边带调制的波形。仿真结果表明,100阶有限冲击响应滤波器可以理想地逼近Hil-bert变换器。该算法共占用了15%的FPGA系统资源,有效降低了使用成本,并且在声频定向扬声器中获得了实际应用。     

Wear performance of Ni/ZrO<Subscript>2</Subscript> infiltrated composite layer

The Ni/ZrO2 was used as raw materials to fabricate the surface infiltrated composite layer with 1-4 mm thickness on cast steel substrate through vacuum infiltrated casting technology. The microstructure indicated that the infiltrated composite layer included surface composite layer and transition layer. Wear property was investigated under room temperature and 450 ℃. The results indicated that the abrasion volume of substrate was 8 times that of the infiltrated composite layer at room temperature. The friction coefficient of infiltrated composite layer decreased with the increasing load. The wear resistance of infiltrated composite layer with different ZrO2 contents had been improved obviously under high temperature. The friction coefficient of infiltrated composite layer was decreased comparing with that at room temperature. The oxidation, abrasive and fatigue abrasion was the main wear mechanism at room temperature. Oxidation abrasion, fatigue wear and adhesive wear dominated the wearing process under elevated temperature.     

Ultrasonic-assisted cloud point extraction for determination of nickel in water samples by flame atomic absorption spectrometry

A novel method for the determination of nickel was established by ultrasonic-assisted cloud point extraction (UA-CPE) prior to flame atomic absorption spectrometry (FAAS) analysis. The nickel reacted with N,N'-bis(salicylidene)-1,2-ethanediamine (BSE) to form hydrophobic chelates, which were extracted into the micelles of alpha-[3,5-dimethyl-1-(2-methylpropyl)hexyl]-omega- poly(oxy-2-ethanediyl) (Tergitol TMN-6). Tergitol TMN-6 was used as green nonionic surfactant. BSE was synthesized and checked by nuclear magnetic resonance (NMR) spectra. The phase diagrams of the binary system, water-surfactant (Tergitol TMN-6), and the ternary systems, water-surfactant-salt, were determined. The effects of experimental conditions including pH of sample solution, concentration of chelating agent and surfactant, ultrasonic power, equilibration temperature and incubation time were evaluated in order to enhance sensitivity of the method. Under the optimal conditions, the calibration graph was linear in the range of 10-500 μg L(-1). The values obtained for the limit of detection and enrichment factor were 1.0 μg L(-1) and 30, respectively. The method was successfully applied to the analysis of nickel in water samples.     

高拱坝安全度计算方法对比分析

超载法、强度储备法和综合法是目前用有限元法分析拱坝整体安全度时采用的主要方法,失稳判据主要有塑性区贯通判据、位移突变判据和屈服体积比突变判据等,分析计算时选择哪种破坏模拟方式和失稳判据目前没有统一的认识.结合工程实例,分析比较了3种计算方法及3种失稳判据的特点.分析结果表明,超载法和强度储备法计算得到的拱坝破坏模式不同;综合法的计算结果与选择的超载、降强的组合形式有关;塑性区贯通判据尚无一个客观指标,受人为因素影响较大;位移突变判据与失稳控制点的选择关系密切;屈服体积比突变判据以坝体及坝基系统的屈服体积为考察对象,受局部材料的强度和结构影响较小.     

基于FPGA的室内智能吸尘平台设计与实现

采用FPGA、多种传感器和其他硬件协同工作的方法;在硬件的选型、仿真和组装,软件的设计、编程与调试等方面做了大量的实验。通过实验找到了软硬件中存在的问题并进行了改善。得到了一个具有遥控和自主吸尘功能、结构简单、成本低、能够智能躲避障碍物的基于FPGA的室内智能吸尘平台。     

Pricing and production decisions in dual-channel supply chains with demand disruptions

This paper develops a two-period pricing and production decision model in a one- manufacturer-one-retailer dual-channel supply chain that experiences a disruption in demand during the planning horizon. While disruption management has long been a key research issue in supply chain management, little attention has been given to disruption management in a dual-channel supply chain once the original production plan has been made. Generally, changes to the original production plan induced by a disruption may impose considerable deviation costs throughout the supply chain system. In this paper, we examine how to adjust the prices and the production plan so that the potential maximal profit is obtained under a disruption scenario. We first study the scenario where the manufacturer and the retailer are vertically integrated with demand disruptions. Then we further assume that the manufacturer bears the deviation costs and obtain the manufacturer’s and the retailer’s individual optimal pricing decision, as well as the manufacturer’s optimal production quantity in a decentralized decision-making setting. We derive conditions under which the maximum profit can be achieved. The results indicate that the optimal production quantity has some robustness under a demand disruption, in both centralized and decentralized dual-channel supply chains. We also find that the optimal pricing decisions are affected by customers’ preference for the direct channel and the market scale change, in both centralized and decentralized dual-channel supply chains.     

Research on multi-robot open architecture of an intelligent CNC system based on parameter-driven technology

This paper presents a multi-robot open architecture of an intelligent computer numerical control (CNC) system based on parameter-driven technology that has been developed for flexible and high-efficiency manipulation. An open architecture control system capable of distributed processing of decision-making and extraction of task information provides a premise for intelligent control and flexible operation. Intelligent detection with database feedback based on real-time assignment of tasks is proposed to achieve dynamic modification of the processing trajectory. In the context of flexible task control, a multi-robot architecture with collision-free path planning and a novel programming approach based on parameter-driven technology are developed. The proposed CNC system has been successfully implemented and demonstrated on an H-beam steel-cutting task that requires flexible and accurate machining.