定形相变储能建筑材料的制备与热性能研究

采用真空浸渗的方法,将棕榈酸和十六醇的低共熔物(PA-HD)与膨胀珍珠岩(EP)结合,制备一种新型定形相变材料(PA-HD/EP).环境扫描电子显微镜测试显示相变材料PA-HD进入到珍珠岩的孔道结构中.棕榈酸和十六醇的低共熔物在膨胀珍珠岩的最佳浸渗量为58.0%(质量分数,下同),在此浸渗量下,即使是没有进行包覆,PA-HD也不会在发生相变时从EP中渗漏.差示扫描量热仪测试获得PA-HD/EP的熔点为41.49℃,相变焓值为122.9J/g.通过在PA-HD/EP中添加10%石墨,改善材料的导热性能.该复合相变材料可以很好地与普通建筑材料进行结合,进一步制备成具有温度调节功能的建筑材料.     

癸酸-棕榈酸/SiO_2相变储湿复合材料的制备与表征

以SiO2为载体,癸酸-棕榈酸为相变材料,采用溶胶-凝胶法制备了癸酸-棕榈酸/SiO2相变储湿复合材料,利用等温吸放湿法、步冷曲线法、FTIR、SEM、激光粒度分析仪(LPSA)、BET、TGA和DSC等对其进行性能测试和表征。结果表明:癸酸-棕榈酸/SiO2相变储湿复合材料的载体材料SiO2具有"笼"结构,其大量微孔形成三维空间网格结构既可以通过癸酸-棕榈酸与SiO2的物理嵌合方式包裹与束缚相变材料,又可以通过SiO2的亲水性能吸附水分子,具有良好的热湿性能。癸酸-棕榈酸/SiO2相变储湿复合材料表面光滑圆润无明显凹陷,颗粒粒径较小且均匀性较好(粒径为82.14nm、孔体积为0.010 7mL/g、孔比表面积为25.16m2/g、孔平均直径为26.63nm),属于纳米级有机相变芯材/无机基体复合材料;相变温度为19.88~23.13℃、相变潜热为38.55~42.56J/g,癸酸-棕榈酸的质量分数约为31.59%,满足人体舒适度的温度范围,适合在建筑领域中广泛应用。     

二元脂肪酸/SiO2复合相变储能材料的制备与表征

针对适用于建筑领域的相变储能材料,选用癸酸(CA)分别与月桂酸(LA)、肉豆蔻酸(MA)和棕榈酸(PA)复合制备了二元低共熔脂肪酸作为储能材料。通过施罗德公式计算得到二元低共熔脂肪酸的混合比例和理论相变温度。基于CA-MA优异的性能,采用溶胶-凝胶法制备CA-MA/SiO2定形相变储能材料。采用FT-IR、SEM、DSC、TG对CA-MA/SiO2的结构、形貌、热性能和热稳定性进行了分析。结果表明,制备的3种二元低共熔脂肪酸适合于建筑领域。CA-MA较好地被固定在SiO2多孔网络中,储能材料和SiO2之间仅为物理结合,没有新物质的生成。定形相变储能材料的相变温度为20.96℃,相变焓为70.17J/g,相变温度适中,相变焓高,热稳定性好。     

基于均匀设计优化制备癸酸-棕榈酸/SiO2复合相变材料

以SiO2作为载体材料,癸酸-棕榈酸作为相变材料制备癸酸-棕榈酸/SiO2复合相变材料.基于均匀设计和多元非线性回归法研究了各因素对复合相变材料吸放湿性能和控温性能的影响.结果表明,各因素对性能影响的主次顺序为:溶液pH值＞无水乙醇与正硅酸乙酯的物质的量比＞癸酸-棕榈酸与正硅酸乙酯的物质的量比＞去离子水与正硅酸乙酯的物质的量比＞超声波功率;优化制备方案:溶液pH值为3.62,超声波功率为100W,去离子水与正硅酸乙酯的物质的量比为9.67,无水乙醇与正硅酸乙酯的物质的量比为5.21,癸酸-棕榈酸与正硅酸乙酯的物质的量比为0.52.     

SiO_2基复合相变材料的制备及性能研究

利用正硅酸四乙酯(TEOS)溶胶-凝胶反应制备了SiO2基复合相变材料,采用了DSC、SEM、FTIR分别对复合材料热性能、形貌和结构进行了表征。结果表明:芯材癸酸比PEG1000和棕榈酸更适合用于建筑和纺织领域。转速为800r/min时,癸酸/SiO2复合材料相变焓为105.3J/g。FT-IR和SEM表征了相变材料与SiO2之间的结合方式和形貌特征。     

基于热湿综合性能的棕榈醇-棕榈酸-月桂酸/SiO_2复合材料制备方案的响应面法优化

采用溶胶-凝胶法制备棕榈醇-棕榈酸-月桂酸/SiO_2复合材料。利用响应面法研究了无水乙醇用量、去离子水用量以及棕榈醇-棕榈酸-月桂酸用量对棕榈醇-棕榈酸-月桂酸/SiO_2复合材料热湿综合性能的影响,并对棕榈醇-棕榈酸-月桂酸/SiO_2复合材料的制备工艺参数进行了优化。结果表明,各因素对性能影响的主次顺序为:无水乙醇用量棕榈醇-棕榈酸-月桂酸用量去离子水用量;在本研究的各参数范围内,优化方案是无水乙醇用量(与正硅酸乙酯的物质的量比)为9.11、去离子水用量为5.21、棕榈醇-棕榈酸-月桂酸用量为0.52。优化棕榈醇-棕榈酸-月桂酸/SiO_2复合材料具有良好的热湿综合性能,即相对湿度50%时,平均平衡含湿量为0.102 0g/g,相变温度为26.81~28.52℃,相变焓为95.69J/g,属于微米级有机相变芯材/无机基体复合材料。     

癸酸-棕榈酸-SiO_2/石膏相变储湿复合材料的制备及性能

以抹灰石膏作为基体材料,将癸酸-棕榈酸-SiO_2相变储湿材料掺入抹灰石膏中,制备癸酸-棕榈酸-SiO_2/石膏相变储湿复合材料,对其基本性能、储湿调湿性能、相变调温性能和耐久性能进行测试与分析。利用FTIR和SEM研究癸酸-棕榈酸-SiO_2/石膏相变储湿复合材料的结构组成和微观形貌。结果表明:当癸酸-棕榈酸-SiO_2相变储湿复合材料掺量为40wt%的癸酸-棕榈酸-SiO_2/石膏相变储湿复合材料具有最佳性能和良好耐久性能。其标准扩散度用水量为0.69、初凝时间为37min、终凝时间为51min、体积密度为916.67kg·m~(-3)、拉伸连接强度为0.08 MPa、抗压强度为1.76 MPa;在相对湿度40%~65%的平衡含湿量为0.0620~0.0849g·g~(-1);从30℃至15℃的降温时间为610s,相变平台明显;经过循环试验,吸放湿性能下降了6.44%~9.45%,相变调温性能仅下降了7.2%。     

表面活性剂协同超声分散制备还原氧化石墨烯＠月桂酸Ｇ棕榈酸复合相变材料及其表征

相变储能材料因能有效地解决能量供求中时间和空间不匹配的矛盾而备受关注。本实验首先采用熔融共混法制得月桂酸(LA)-棕榈酸(PA)低共熔混合物后,将其与还原氧化石墨烯(RGO)混合,通过超声分散制得还原氧化石墨烯@月桂酸-棕榈酸(RGO@LA-PA)复合相变材料。FT-IR、Raman、SEM、DSC和形貌稳定性的分析结果表明,RGO与LA-PA是以物理方式结合,所添加的RGO能对材料形成均匀包覆,仅1%(质量分数)的RGO就能使其导热系数提升20%为0.426 W·m-1·K-1,相变潜热为159.9 J·g-1,起始分解温度提高2 ℃;经100次热循环后,其相变潜热仅下降2%,说明RGO包覆相变材料后提高了其导热性能,改善了其渗漏现象,同时该复合相变材料还具有良好的热稳定性。     

优化制备棕榈醇-棕榈酸-月桂酸/SiO_2复合相变调湿材料

以SiO2为载体材料、以棕榈醇-棕榈酸-月桂酸为相变材料制备棕榈醇-棕榈酸-月桂酸/SiO2复合相变调湿材料,基于均匀设计和多元非线性回归法研究了各因素对复合相变调湿材料调湿性能和控温性能的影响。结果表明,各因素对性能影响大小的排序为:无水乙醇与正硅酸乙酯的物质的量比、溶液pH值、棕榈醇-棕榈酸-月桂酸与正硅酸乙酯的物质的量比、超声波功率、去离子水与正硅酸乙酯的物质的量比;优化制备方案为:溶液的pH值为2.68、超声波功率为113W、去离子水与正硅酸乙酯的物质的量比为9.03、无水乙醇与正硅酸乙酯的物质的量比为5.22、棕榈醇-棕榈酸-月桂酸与正硅酸乙酯的物质的量比为0.51。     

癸酸-棕榈酸-硬脂酸/膨胀石墨蓄能复合相变材料的制备与热性能研究

癸酸、棕榈酸、硬脂酸形成的三元低共熔物与膨胀石墨通过真空浸渍法制备出新型癸酸-棕榈酸-硬脂酸/膨胀石墨储能复合相变材料,适宜的质量比为m(癸酸)∶m(棕榈酸)∶m(硬脂酸)=77.0∶11.5∶11.5,m(癸酸-棕榈酸-硬脂酸)∶m(膨胀石墨)=13∶1。采用DSC、FT-IR、TG、SEM、冷热循环实验和蓄/放热实验研究了材料的结构和热性能。SEM和FT-IR分析结果表明低共熔物与膨胀石墨是通过物理吸附方式结合。DSC结果表明复合材料融化和凝固时的相变温度为28.93℃和16.32℃,相变潜热为137.38J/g和141.51J/g。TG结果表明复合相变材料在100℃以下具有良好的热稳定性。500次热循环和蓄/放热实验表明循环前后复合相变材料的热可靠性好,且使用寿命长。膨胀石墨的添加改善了复合材料的热性能和热导率。研究表明制备的新型复合相变材料具有合适的相变温度、较高的相变潜热和热导率,热性能稳定可靠,可用于低温蓄能领域。     

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 ...     

Effect of Oxide Assisted Metal Nanoparticles on Microstructure and Morphology of Gallium oxide Nanowires

Several researches have been reported about the characteristic of β-Ga2O3 nanowires which was synthesized on nickel oxide particle. But indeed, recent researches about synthesis of β-Ga2O3 nanowires on oxide-assisted transition metal are limited to nickel or cobalt oxide catalyst. In this work, Gallium oxide (β-Ga2O3 ) nanowires were synthesized by a simple thermal evaporation method from gallium powder in the range of 700 - 1000℃ using the iron, nickel, copper, cobalt and zinc oxide as a catalyst, respectively. The β-Ga2O3 nanowires with single crystalline without defects were successfully synthesized at the reaction temperature of 850, 900 and 950℃ in all the catalysts. But optimum experimental condition in synthesis of nanowires varied with the kind of catalyst. As increasing synthesis temperature,the morphology of gallium oxide nanowires changed from nanowires to nanorods, and its diameter increased. From these results, we could be proposed that the growth mechanism of β-Ga2O3 nanowires was changed with synthesis temperature of nanowires. Microstructure and morphology of Synthesized nanowire was characterized by HR-TEM, FE-SEM, EDX and XRD.     

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