高速电机驱动的逆升压式空气循环制冷系统研究

介绍了高速电机驱动技术在空气循环制冷系统中的2种主要应用形式--悬臂式和紧凑式方案,讨论了高速电机驱动的新型逆升压式空气循环制冷系统的工作原理,并对小功率高速电机驱动的逆升压式空气循环制冷系统进行了性能计算和试验研究.结果表明,该方案可提供2.5 kW等级的制冷量,是一种新型制冷系统.     

户式中央空调制冷系统探讨

目前,户式中央空调越来越被人们关注.本文对户式中央空调常规单向膨胀阀制冷系统与常规双向膨胀阀制冷系统进行论述,并针对常规双向膨胀阀制冷系统的缺点,提出了改进意见.     

制冷装置的Yong效率分析

本文讨论了Yong分析法在制冷循环中的应用，分析子制冷系统中各装置的Yong平衡，导出了各装置的Yong损的计算式。     

侧壁式气垫船水压场试验研究

在拖曳水池中对侧壁式气垫船的水压场进行了系统测量，得到不同水深，不同航速和不同横向位置水底扰动压力系数的纵向通过特性曲线，分析总结了侧壁式气垫船水压场规律。     

中小型渔船制冷技术的研究进展

远洋渔船带有制冷装置，而100吨以下的中小型渔船因其柴油机的限制，无法安装压缩机式制冷机。出海作业时，均需携带冰块做渔产保鲜。本文介绍压缩式渔船制冷的现状，回收渔船尾气余热的吸收式制冷系统，吸附制冷的冷冻水系统，吸附式制冰系统等实验装置。其中吸附式制冷系统具有良好的开发价值。     

自复叠制冷系统中套管式冷凝器的应用研究

自复叠制冷系统广泛应用于小型制冷装置,制取-40℃~-150℃之间的低温环境。套管式冷凝器在自复叠制冷系统中常用作冷凝设备,其特性与结构深刻地影响着制冷装置系统。自动复叠制冷系统用套管式冷凝器为研究对象,研究其冷凝过程特性和结构尺寸;在冷凝压力2.0 MPa,当R600a和R23混合工质的质量分数为7∶3时,计算其冷凝负荷为1610 W;根据混合工质和冷却水的换热系数,确定套管式冷凝器长度为4.842 m。最后对不同冷凝水流量的吸气温度、排气温度、蒸发温度,以及冷却水进出口温度进行了对比分析。     

气垫船噪声及其阻尼降噪

一、气垫船概况 气垫船(Air Cushion Vehecls)是五十年代发展起来的新型而独特的交通工具之一。这是根据英国工程师克里斯托弗·科克雷尔(Chinstopher cockerell)首创的气垫理论而发展起来的。 气垫船的工作原理如图1和图2所示。它可分为全垫升式气垫船(Hovercraft)和侧壁式气     

小型制冷压缩机瞬态起动特性研究

在小型制冷系统中，转子式压缩机的制冷效果不及往复式压缩机，因而限制了转子式压缩机的推广应用。利用作者研制的起动电流测试装置，对不同结构的小型压缩机的瞬态起动特性进行了实验研究，提出了阻止工质在停机后的质量迁移来提高转子式压缩机制冷效果的观点．并进行了压差起动可靠性试验。本研究工作为转子式压缩机在小型制冷系统上的推广应用提供了理论依据。     

速冻装置及其制冷系统技术参数的确定

本文论述了速冻装置及其配套制冷系统主要技术参数的确定。其中速冻装置包括负速设计；风速场设计；温度及温度场设计；发器及其传热温差的设计等。制冷系统包括制冷系统的划分；冷藏温度的确定；冷藏器娄面积的确定，速冻装置对制冷系统的特殊要求。     

制冷系统用节流装置特性及应用分析

介绍了制冷系统用节流装置的特性、工作原理和应用场合,对手动节流阀、浮球式节流阀、毛细管、热力膨胀阀、电子膨胀阀及节流孔板进行了详细的工作原理分析,同时根据不同节流装置的实际应用组合方式的应用方法给出了解释和建议。     

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.     

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.     

新闻(英文)

正China and Greece Sign the Standardization Cooperation Agreement Witnessed by Chinese Premier Li Keqiang and Greek Prime Minister Antonis Samaras,AQSIQ Minister Zhi Shuping and ELOT Chairman and Executive Director Angelos Tolkas signed the SAC-ELOT Standardization Cooperation Agreement.The Agreement is one of the critical cooperation documents signed during Li Keqiang’s visit in Greece,encouraging China and Greece to