利用电容式传感器测量液位的研究

采用差动电容差压传感器测量液体的压力,利用液体的压力公式计算液位,设计了一种便携式低功耗液位仪。该仪器可以实现液位信号的采集和运算,同时还配有温度检测系统,通过软件编程对液位进行温度补偿,同时计算出液位值,最后结果由LCD显示。     

声速经验公式的适用范围分析

声速经验公式是海水中温度、盐度和静压力的函数,通过对直接测量声速和间接测量声速的分析,并应用近年来收集的南海声速剖面仪SVP和CTD数据,对九种声速经验公式计算的声速与直接测量声速的差异进行了分析,得出了声速经验公式的计算差异范围,结果表明各个声速经验公式各有优势,不同的公式适用的范围也不一样,并给出了在不同的范围内应用何种声速经验公式能获得较高精度的结论。     

基于群延时分析的海水声速测量

在海水声速测量过程中,测量系统存在群延时,影响测量精度.建立声速直接测量系统信号传输模型,分析系统群延时及换能器群延时.建立声速直接测量系统并在恒温水槽中完成测量实验,所测量的声速值与某高精度声速仪测量声速值相差小于0.3 m/s,与经验公式计算声速值相差小于0.1 m/s.实验结果表明,系统群延时分析方法可用于声速测量.     

抚仙湖各个月份的温度剖面

对多年来抚仙湖温度剖面测量数据进行了统计分析,给出了抚仙湖各个月份温度剖面,并利用己有的声速经验公式算出了相应的声速剖面。还对试验中发现的一些现象进行了简要叙述。     

基于冰内孔隙率的冰中声速经验公式的研究

冰介质中的声速特性受温度、盐度、密度等因素影响,是一个随时间和空间变化的不稳定值。研究了冰介质中温度、盐度、密度三个物理量在垂直方向上的变化特性,引入孔隙率作为冰中声速特性的表征因子,利用孔隙率与温度、盐度、密度已有的函数关系,通过大量天然冰的实验数据,得到淡水冰中声速关于温度、盐度和密度的经验公式。进行了河冰声速测量的外场试验,验证了淡水冰中声速的经验公式的有效性,并利用该声速经验公式研究了淡水冰垂直方向上的声速剖面。文中所做的相关研究可为以后研究利用冰介质中的声速特性提供借鉴,为以后利用声学方法,在极地或我国北方高纬度地区进行冰层厚度监测,了解寒地冰层的更替、演化以及气候变迁等工作奠定研究基础。     

关于测量法计算立式罐底部厘米容积的研究

本文根据等面积同心圆的原理,以基准点高h_j力零时的平面作为参照水平面,推导出计算底部基准点(或称为底部下尺点)以下死量的计算公式;并以h~j为变量,利用该公式还可计算出液位为1cm、2cm、……等相应的底部厘米容积。     

爆破振动对岩质边坡累积损伤影响实验研究

通过观测同一地点岩体多次爆破前、后岩体的声速以及爆破振动速度峰值变化规律,由声速测试结合爆破振动测试数据结果计算出岩体损伤系数,实测数据的对比和计算结果表明:在多次爆破振动损伤累积的条件下,爆破振速随岩体的声速呈指数关系衰减.并由声速测试结果确定了边坡在爆破振动作用下的损伤阈值.     

光伏电站智能清洗模型及实例分析

提出了一种光伏电站智能清洗计算模型与方法。利用光伏电站的历史运行数据建立光伏组件清洗前后发电出力的专家数据库,基于该数据库建立智能清洗专家系统,将光伏组件清洗后的实测辐照度代入该模型,计算得出光伏组件以及该光伏电站的实时功率损失及在某时间段内损失的发电量,计算出光伏组件效率。通过利用现场数据模拟计算,验证了该计算模型与方法的有效性,可对浮尘原因造成的光伏电站出力损失做出准确计算。该方法既可提高光伏电站的运行管理水平,还可为光伏电站运营维护提供准确的数据支持。     

基于固定频段声波共振原理的液位测量方法

已有声共振液位测量方法的量程受限于所获取的初始共振频率,这制约了此类方法在长距离测量中的应用。针对该问题,给出一种基于固定频段内共振频率的液位测量新方法。首先将检测初始共振频率变为检测较高频段内出现的一组共振频率。利用相邻共振频率的等差关系及共振频率液位换算公式得到多个测量值,将它们取平均后作为最终液位值,从而有效地降低测量不确定度。此外,提出的检测算法可以快速获取共振频率,增加了测量的实时性。最后,通过实验验证了所提方法量程更长,受液面泡沫、残渣等障碍物影响小,测量精度可达1‰,优于已有声共振测量方法以及一般超声波液位仪3‰~5‰的测量精度。     

南海海底粉质黏土沉积物声速和衰减的全浸式测量

提出了一种宽带声速和声衰减测量方法,该方法利用全浸式传感器测量技术(FITM)在实验室环境下对超细沉积物(平均粒径为5.27 μm,孔隙率为79%)的声速和声衰减进行了测量。为确定该实验室测量方法的可靠性,将该声速与声衰减关系与Kramer-Kronig关系进行了比较。同时,Hamilton经典曲线表明,该实验室测量结果符合声速与孔隙度关系,且声衰减在Hamilton曲线置信区间内。测量数据满足有效密度流体模型和颗粒剪切模型的声速和衰减预测曲线,进一步证明了实验室测量方法的准确性和有效性。     

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.