基于非匀速模型的早期火灾源点定位及强度估计

针对传统匀速模型早期火灾源点定位方法的不足,提出了一种非匀速早期火灾顶棚射流传播距离与时间关系的扩散模型.根据传感器探测信号的延时差,逆向利用该非匀速模型,并结合微粒群算法进行求解,同时实现了对早期火灾源点的准确定位和强度的定量估计.通过应用烟气传感节点所组成的无线传感网络验证了该算法.     

基于可能性分布的无线传感器网络可靠性分析

将传感器节点失效行为用可能性分布来刻画,通过引入结构函数,建立传感器节点与网络状态的关系,构造出了一种无线传感器网络可能可靠性函数.该函数表示无线传感器网络在观察时刻网络状态不低于某一值的可能性.通过实例分析,所构造的函数能够有效评价所部署的无线传感器网络的可靠性.     

综合无线信号传输与多信息融合技术的火警系统设计

本文提出了一种基于多传感器融合技术与无线信号传输的火警系统设计，其中多传感器融合技术有效地提高了火灾探测报警系统的可靠性、降低误报率，缩短火灾探测报警时间，及时采取有效措施灭火：设置无线连接装置，防止在发生火情时造成导线胶皮熔裂，影响设备正常工作，另外，通过现代无线通讯技术实现火情发生立刻报警、告知用户的功能。     

无线通信技术在地铁火灾自动报警系统中的应用

地铁发生火灾会造成极为恶劣的影响,地铁部分区域建筑（车站端头设备房、外挂设备房）走线困难,检修不便,无线通信技术在地铁火灾自动报警系统中有广泛的应用前景。该文通过无线通信技术设计了地铁火灾自动报警系统,以FPGA为核心控制芯片,以ZigBee技术为无线通信协议。每个无线节点上分别设置配置气雾传感器、二氧化碳传感器、显示模块、报警模块以及无线通信功能模块。对每个无线节点的通信功能进行软件设计,给出了具体的流程图。验证试验表明：当模拟火灾发生时,每个节点上的气雾传感器准确地监测到火灾,并能通过显示模块和报警模块以视频和声音的形式报警,而无线通信模块也将火灾监测信息顺利发送到上位机。     

水声网络探测节点的自主式能量检测器

推导了一种适用于水声无线传感器网络探测节点的自主式被动目标检测器，并进行了仿真验证。     

什么是无线传感器网络（WSN）？

无线传感器网络主要由三个部分组成：节点、网关和软件，空间分布的测量节点通过与传感器连接列周围环境进行监控，监测到的数据无线发送至网关．网关可以与有线系统相连接，这样就能使用软件对数据进行采集、加工、分析和显示。路由器是一种特别的测量节点．你可以使用它在WSN中延长距离以及增加可靠性。     

面向机械振动监测的无线传感器网络节点的设计

针对机械振动信号监测的特点和现有无线传感器网络节点的不足,提出了一种基于MEMS加速度传感器的无线传感器网络大容量测振节点的设计.节点采用了模块化的设计思想,主要包括AVR微控制器、可编程逻辑器件CPLD、多通道16位A/D转换器、SD卡存储器和MEMS传感器,初步解决机械振动信号采集和大容量存储的难题.通过实验验证了该设计方案的可行性.     

一种基于多传感器信息融合的火灾探测系统

根据火灾的特征与燃烧产物,设计了一种基于多传感器信息融合的火灾探测系统.该系统以DSP TMS320LF2407A为处理器,包括一氧化碳传感器模块、温度传感器模块和紫外火焰传感器模块.紫外火焰传感器可以很好地区分闪燃火和阴燃火,一氧化碳传感器和温度传感器能够对闪燃火和阴燃火产生不同的反应,因此系统采用两种不同的算法来探测闪燃火和阴燃火.该火灾探测系统在燃烧室中通过了实验验证.实验表明,该火灾探测系统比通用的感烟型探测器具有更快的探测速度和准确度,且不会在常见干扰源的干扰下产生误报警.     

嵌入式无线传感器网络研究

简要叙述了无线传感器网络的发展史,讨论了传感器节点的功耗、成本、组网方面的属性及要求,概述了传感器节点的传感单元、通信单元、处理单元及供电单元等四大基本功能单元和两个辅助单元,介绍了一些常用电池和几款适合嵌入式节点设计的微控制器和射频器件,阐述了无线传感器网络领域一些挑战性的问题以及传感器节点的能量管理问题.     

卡尔曼滤波在无线传感器网络节点定位中的应用

为了减小无线传感器网络节点定位中节点测距误差和定位算法自身引入误差的积累对定位精度的影响,建立了适用于无线传感器网络的卡尔曼滤波模型.采用渐消自适应卡尔曼滤波对基于距离的初始定位算法进行求精,通过一跳节点间的相互制约,在全局范围对未知节点进行定位;基于卡尔曼滤波模型,对无线传感器网络的分布式算法和集中式算法的计算量进行了研究,得出计算量与节点数目的关系.研究结果表明,卡尔曼滤波能够有效提高节点的定位精度,尤其适用于网络节点密度小、信标节点比例低的情况.     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.