跟踪测量视频的高精度同步采集系统

设计了一种无损实时跟踪测量视频和测控数据同步采集系统。根据测控信息同步信号及其对视频采集时刻的规定,以测控信息采集卡上高精度定时器为时钟,由视频采集卡通过软件修正摄像机曝光信号,实现对曝光时刻的精密调节。采用高速总线实现数据无失真存储和转储、AVI技术组织文件,充分利用了测量视频图像空间。     

机动车超速监测系统现场测速误差检定装置研制

为更准确地检测机动车超速监测系统现场测速误差,以社会车辆为目标速度源,在机动车超速监测系统的临近位置,架设更高精度的测速装置,对相同速度监测和图像采集区域内的社会车辆,进行同步测量和同步图像采集,通过对比两者的速度量值实现对超速监测系统的检定校准。该装置用于检定道路超速监测系统的速度量值线性与误差,可以测量足够多的社会车辆样本,重点选取限速点附近的速度测量值进行对比分析。装置安装简单,使用方便,可以大幅提升检定效率与操作安全性。     

基于跨层设计的机械振动WSNs同步采集多跳累积误差控制方法

针对机械振动无线传感器网络跨层同步采集精度随网络深度增加而急剧降低的问题,建立同步采集关键同步信息传输模型,分析多跳同步误差累积机理,得出嵌入式软件调度实时性不高、晶振随机抖动及无线链路随机迟滞是多跳误差累积主要原因。由此提出基于跨层设计的机械振动无线传感器网络同步采集多跳累积误差控制方法:提出多路硬件跨层设计消除嵌入式软件调度迟滞影响,提高同步任务实时性;采用高精度有源晶振抑制晶振随机抖动;建立无线链路跨层传输随机迟滞数学模型,采用回归分析方法校准由此导致的同步信息随机抖动及传输时延计算误差,提升同步采集精度。最后组建4跳网络进行同步采集对比试验,实验结果表明多跳累积误差得到有效抑制。     

对单反相机TTL测光的认识与选择

对单反相机ＴＴＬ测光的认识与选择王振生摄影爱好者，在选择新单反相机时，多数人往往把注意力放在选择相机有哪些主要曝光功能上；追求相机快门速度是否有１／４０００秒、１／８０００秒，闪光同步速度是否达到１／１２５秒。１／２５０秒，以及自动曝光功能是否有程控...     

用闪光同步速度来检测快门速度的准确性

用闪光同步速度来检测快门速度的准确性影友们都知道，在使用焦平面快门相机进行闪光摄影时，必须将快门至于相机的最高同步速度之内，否则会造成部分底片不能曝光而使其报废。这个最高同步速度，在相机的速度调节盘上都有明显的标志，（大都用红色或橙色的数字表示）一般...     

基于AD7173的多通道数据采集高速存储系统

为解决测试系统中弹内空间狭小、无法同时容纳多套传统数据采集系统的问题,设计基于AD7173的多通道数据采集高速存储系统,实现对多传感器(四轴MEMS加速度计、四轴MEMS陀螺仪、三轴地磁传感器和温度传感器)的高精度采集存储。选用∑-Δ型高精度模数转换芯片AD7173实现对多路传感器信号的模数转换;在转换时实时监测数据的准确性,并通过芯片的RDY引脚作为STM32外部中断来判断是否转换完成,以此来实现高精度的数据采集,并通过流水线设计实现数据的高速存储。试验结果表明:输入角速率与敏感角速率误差控制在±0.0017°/s以内。对多个传感器的采集验证表明该数据采集高速存储系统能够实现对多通道信息的高精度采集存储,具有一定的工程应用价值。     

阳光同步闪光的正确运用

阳光同步闪光,即拍摄时同时使用闪光灯和太阳光两种光线同时曝光,借以达到改善现场照明或取得某种特殊的照明效果。不可否认,许多拍摄现场的照明光线都不太尽人意,改善的手法就是采用阳光同步闪光。例如,在强烈的阳光下将阴影减轻;逆光时想取得背景和人物平衡的曝光;在灰暗的天空下使人物取得明快的照明;拍摄夜     

CCD目标灰度质心算法的动态误差分析

针对传统静态误差分析方法忽略目标运动对测量影响的不足,本文在分析运动对目标形状影响的基础上建立了灰度质心算法误差与灰度噪声、动态目标尺寸的数学模型,该模型表明当曝光时间内目标移动量远小于目标静态尺寸时,动态误差与静态误差接近;而当目标移动量与目标静态尺寸的比值大于6%时,灰度质心算法动态测量误差方差将比静态测量误差方差...     

地震数据采集无线同步技术研究

针对地震勘探中时间同步问题和其他数据采集领域的采集同步问题,设计并完善基于GPS授时技术的同步技术方案,利用GPS授时信号全方位、实时性、连续性和高精度的特点,以GPS的PPS信号为基准来校准本地时钟,采用单片机和无线通信技术实现数据采集同步。通过对无线遥测各道地震数据进行同步处理,解决了当地震勘探仪采集的道数增多时数据采集和存储的实时性问题,特别是解决了未来数字式检波器中独立同步和分时处理等关键问题。     

CMOS图像传感器阵列在μ秒级物理暂态摄像系统中的应用

介绍TCMOSN像传感器阵列在物理暂态摄像系统中的应用方法。通过时序控制火花点阵闪光与传感器阵列曝光保持同步，拍摄到0．5μ火花图像．验证了原理的可行性。CMOS图像传感器阵列为4x4方阵，分时顺序控制，拍摄间隔在0-9999μ内可调，为高速摄像技术提供了新的方法。     

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.……     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

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.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

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 ...