膨胀石墨/LiCl-NaCl复合相变材料导热系数各向异性

用水溶液法制备了膨胀石墨/LiCl-NaCl复合相变储能材料,利用扫描电镜观测了试样的微观形貌,并且利用Hot-Disk热学常数分析仪测试了试样常温下的导热系数。实验结果表明,共晶盐能够被吸附到石墨片层之间,形成稳定、均一的复合相变材料;其导热系数随压力和石墨含量的增加而不断增大,并具有各向异性;成型压力和膨胀石墨掺量是影响其性质的两个重要因素,在一定范围内,其导热系数和各向异性随成型压力的增加而增大,压力超过一定范围,两者变化幅度减小;石墨掺量达不到一定比率时,其导热系数和各向异性变化不显著,当达到一定比率后,两者变化幅度增大;成型压力和膨胀石墨掺量对其导热系数的影响有耦合作用;通过取向度Φ给出了垂直压力和平行压力方向上的导热系数计算公式。     

己二酸/膨胀石墨复合相变材料性能研究

以己二酸为相变材料,膨胀石墨为导热增强相,采用机械混合与熔融吸附的方法,制备出己二酸/膨胀石墨复合相变储热材料。通过FT-IR、DSC、热常数分析仪、TG、FE-SEM及热循环实验对制备的复合材料进行了结构和性能研究。结果表明,膨胀石墨能够有效吸附己二酸,两者之间化学相容性良好;随着膨胀石墨掺量的增加,复合材料的相变潜热有减少趋势,导热系数则相应提高;当膨胀石墨的掺量为8%(质量分数)时,制备的复合材料的熔化、凝固相变潜热分别为237.66,220.49J/g,导热系数为2.99W/(m·K),具有良好的热稳定性。     

储热型吸附式空气取水器吸附剂与储热材料的选择

本文针对太阳能储热型吸附式空气取水器吸附剂和储热材料的选择,分别研究了以膨胀硫化石墨(ENG-TSA)和以活性炭纤维(ACF)毡为基质的复合吸附剂的导热系数和吸附性能,硬脂酸/膨胀硫化石墨(ENG-TSA-SA)复合相变储热材料的导热系数与DSC测试。结果表明:ENG-TSA-LiCl复合吸附剂的导热系数最大可达5.67 W/(m·K),吸水量最大可达1.54 g/g。真空浸渍法获得的ACF-LiCl复合吸附剂的吸水量比大气浸渍法高。ASLi40固化吸附剂的吸水量为1.59 g/g,适用于大批量生产。ENG-TSA-SA的径向导热系数为22.2 W/(m·K),相变温度区间为65.9~77.1℃,适用于太阳能等低品位热能。储热器的添加明显延缓了解吸温度降低的趋势。     

氯化钙/膨胀石墨混合吸附剂导热性能研究

研究出具有良好的导热性能的吸附剂是吸附制冷的关键。利用耐驰LFA447导热仪测试了不同质量配比（氯化钙与膨胀石墨的质量比）和不同固化压力下氯化钙—膨胀石墨固化混合吸附剂的导热性能。实验结果表明：在一定范围内,在相同的质量比下随着固化压力的增大,导热系数不断增大;在相同的固化压力下随着氯化钙—膨胀石墨质量比的增大导热系数不断减小。在测试的所有样品中,当固化压力为1.7KN,氯化钙—膨胀石墨的质量比为2：1时,混合吸附剂的导热性能比较好,导热系数达到2.7 W/(m?K)。     

膨胀石墨对石蜡膨胀石墨复合相变材料热工性能的影响

在石蜡中加入不同含量的膨胀石墨制备了石蜡/膨胀石墨复合相变材料,通过测定不同膨胀石墨掺量的复合相变材料的导热系数、比热容、蓄热系数、热稳定性、热膨胀系数等参数,探究了膨胀石墨对石蜡的热工性能的影响规律。结果表明,膨胀石墨的加入,复合相变材料的导热系数呈线性增大,传热能力增强,蓄热时间缩短,蓄热系数增加,使石蜡的热效率提高;同时,冷热循环过程中,热膨胀系数减小,化学结构稳定,封装效果良好,具有较好的热循环稳定性和热化学稳定性,使石蜡的热稳定性提高。     

不同吸附量条件下氯化锶混合吸附剂-氨的导热系数与渗透率研究

氯化锶作为一种化学吸附剂,其主要特征是在吸附与解吸过程中会出现膨胀与结块现象,这种现象会进一步影响到吸附剂的导热系数与渗透率。为了确定在这种条件下氯化锶的导热系数与渗透率变化规律,研究中先选择膨胀石墨为基质对氯化锶进行了传热强化。即按照3种不同比例、2种不同固化密度配制了氯化锶/膨胀石墨固化混合吸附剂,然后在不同吸附量的条件下采用稳态法以及Ergun模型原理对样品进行了导热系数和渗透率测试。测试结果表明,随着制冷剂含量的升高,氯化锶化学吸附剂导热系数值增加幅度偏大。当配制比例为83%,固化密度为450 kg/m3时,其导热系数可从0.88W/(m?K)最高上升至1.61W/(m?K),同时氯化锶混合吸附剂渗透率随着制冷剂含量的升高而有所下降。     

无机盐/膨胀石墨复合相变材料的制备及性能研究

为了改善单一相变材料易泄露、潜热较低、稳定性差等问题,以三水合乙酸钠作为主要相变材料,十二水合磷酸氢二钠作为成核剂,聚丙烯酸钠作为增稠剂,膨胀石墨作为导热增强剂,通过熔融共混法制备了形状稳定的复合相变材料。通过步冷曲线法、DSC差示扫描量法、SEM扫描电镜及热循环实验对材料特性进行表征和测量。结果表明,膨胀石墨可以较好地吸附基底材料,起到导热桥架的作用,当膨胀石墨的含量逐渐增加时,复合相变材料的相变温度略微降低,过冷度有效减小,导热系数大幅提升,储热性能没有显著变化。综合分析,复合相变材料的最佳配比为n(SAT)∶n(DSP)∶n(PAAS)∶n(EG)=100%∶4%∶1%∶8%,其相变温度为57.1℃,相变潜热为219.2 kJ/kg,具有良好的热稳定性。     

炭化活化法制备木屑氯化钙复合吸附剂

为解决氯化钙吸氨过程中的膨胀结块和性能衰减,以氯化钙和木屑为原料,利用炭化活化造孔的方法在实验室自制了复合吸附剂.考察了炭化活化温度对吸附剂性能的影响,测试了吸附剂的吸氨性能、微观形貌、结晶度和比表面积.研究表明:所制备的吸附剂孔隙发达,氯化钙含量高(达到80%)且分布均匀,解决了吸氨过程中的膨胀结块和性能衰减;吸附剂的吸氨性能随炭化活化温度的升高先增加后减小,600℃下制备的吸附剂具有最好的吸附性能,5 min内其吸附量和对应的SCP(单位质量吸附剂的制冷功率)分别为0.19 g/g和793.9 W/kg.     

TDA-HDA/膨胀石墨复合相变材料的制备及性能研究

脂肪胺作为有机相变材料有着相变焓高、无毒低腐蚀、化学性质稳定等特点，在建筑围护结构的中低温相变储能领域有着广泛的应用前景。利用高导热率的膨胀石墨作为多孔介质，吸附十四胺-十六胺二元共晶相变材料制备了复合相变材料，膨胀石墨质量分数分别为5%、10%、15%和20%,定型后的密度分别为600,700,800和900 kg/m³。采用扫描电镜、DSC、步冷曲线、导热系数测定仪和TG测试仪等对十四胺-十六胺/膨胀石墨复合相变材料的性能进行表征。实验结果表明膨胀石墨质量分数为10%时能完全吸附十四胺-十六胺二元相变材料，融化和凝固温度分别为27.48和21.86℃,相变焓为226.7 W/g,约为十四胺-十六胺相变焓(249 W/g)的90%,导热率可提高到十四胺-十六胺的373%～500%。当密度达到800 kg/m³以后，导热率随密度变化幅度减小。热循环实验表明十四胺-十六胺/膨胀石墨复合相变材料的热稳定性良好。红外光谱测试结果表明二元相变材料与膨胀石墨为物理结合，不存在化学反应；TG测试结果显示在常温范围内，相变材料的存在稳定，适用于建筑围护结构...     

三水醋酸钠导热性能改善实验研究

为了提高以三水醋酸钠为基质的复合相变储热材料（PCM）的导热性能,选用铜粉、碳粉、膨胀石墨作为导热系数改善剂,并进行对比实验,结果表明铜粉、碳粉与复合PCM混合后分层明显,而膨胀石墨的混合效果较好,且当膨胀石墨体的积分率约为10%时,利用其多孔吸附特性和较好的导热性能,对复合PCM（含增稠剂和成核剂）的导热性能改善明显。     

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