钼改性酚醛树脂的制备与表征

采用钼改性酚醛树脂（PF），结果表明，钼改性PF的耐热性比纯PF有明显提高，当钼含量为5％时，合成的PF耐热性最好，初始分解温度约为362℃，比纯PF提高112℃；切线法得到的外延分解温度约为410℃，比纯PF升高了117℃；500℃时失重约38％，比纯PF有明显提高；红外光谱表明钼元素以钼氧键的形式引入到PF结构中。     

纳米铜改性酚醛树脂及其应用性能

采用新发明的原位生成法成功地制备了摩擦材料用纳米铜改性酚醛树脂。利用XRD和TEM对所制备的树脂进行了表征。结果显示,纳米铜的粒径为10~40 nm,呈近球形。进行了TGA、冲击试验和摩擦试验。结果表明,纳米铜改性酚醛树脂的耐热性有较大提高,与纯酚醛树脂相比,其初始分解温度和半分解温度可分别提高31℃和46℃;纳米铜改性酚醛树脂基摩擦材料的韧性和摩擦学性能有明显改善,与纯酚醛树脂基摩擦材料相比,冲击强度提高44%,热衰退率和磨损率分别降低约50%和2/3。建立了酚醛树脂/纳米铜复合材料的界面模型,并探讨了纳米铜改善酚醛树脂及摩擦材料性能的机理。      

原位同生法制备纳米铜改性酚醛树脂

利用新发明的原位同生法成功地制备了摩擦材料用纳米铜改性酚醛树脂。经过X射线衍射分析证实，利用该方法制备的树脂中含有单质铜。用透射电子显微镜表征了铜粒子的形貌：呈球形，粒径为10nm～40nm。通过热重分析和冲击试验，对合成树脂的热性能和韧性进行了研究。结果显示，制备树脂的初始分解温度和半分解温度随纳米铜含量的增加先升高后降低，在含量为7％时分别达到最大值；制备树脂基摩擦材料的冲击强度随纳米铜含量的增加先增大后下降，在含量为5％时达到最大值。建立了纳米铜粒子与酚醛树脂相互作用的物理模型，并分析了纳米铜提高酚醛树脂热性能和韧性的机理。     

钼改性酚醛树脂的制备与表征

采用钼改性酚醛树脂(PF),结果表明,钼改性PF的耐热性比纯PF有明显提高,当钼含量为5%时,合成的PF耐热性最好,初始分解温度约为362℃,比纯PF提高112℃;切线法得到的外延分解温度约为410℃,比纯PF升高了117℃;500℃时失重约38%,比纯PF有明显提高;红外光谱表明钼元素以钼氧键的形式引入到PF结构中。     

蒙脱土插层改性酚醛树脂复合材料及其摩擦磨损性能

利用单体原位插层的方法制备酚醛树脂/蒙脱土复合材料,研究了蒙脱土的有机化改性和不同有机化蒙脱土含量对酚醛树脂耐热性的影响,以及改性后的酚醛树脂对摩擦材料性能的影响,结果表明:经改性的酚醛树脂的耐热性能要明显优于未改性的酚醛树脂,初始分解温度达487.1℃,比未改性的提高了60.9℃,600℃时的质量剩余率达54.84%,提高了38%。100~350℃摩擦系数为0.33~0.40,250℃时未改性树脂基摩擦材料磨损率为0.56×10-7/N·m,改性后树脂基摩擦材料磨损率为0.44×10-7/N·m,下降了27.2%。     

新型水溶性含季铵碱基感光树脂的合成及性能

研究了作为新型水显影阻焊剂的含丙烯酸酯基及季铵盐基的酚醛树脂用碱的醇溶液改性成为水溶性的含季铵碱基及丙烯酸酯基的酚醛树脂的反应条件,并研究了对其感光性能的影响,用TGA测定季铵离子基热分解温度。结果指出,改性转化率可达90％,产物保持水溶性,而其离子热分解温度明显下降至120℃,但感光性能有一些下降。     

摩阻材料用亚麻油改性酚醛树脂的研究

合成了亚麻油改性酚醛树脂(PF),FT-IR谱图说明亚麻油成为PF分子结构的一部分。综合热分析表明改性PF在320℃~600℃间失重53.11%,普通PF失重73.51%;普通PF热分解峰为400℃~425℃和540℃~600℃,而亚麻油改性PF热分解峰在440℃~470℃和600℃~660℃。亚麻油改性PF作基体的摩阻材料的摩擦磨损性能和力学性能测试表明,改性PF的粘接性和韧性均得到提高,摩阻材料摩擦系数大,摩擦性能稳定,磨损率低,冲击强度大,硬度适中,改性PF可作为高性能摩阻材料基体。     

桐油改性线型酚醛树脂的制造及应用研究

介绍桐油改性线型酚醛树脂的制造方法及应用研究。苯酚，甲醛，桐油在酸催化下进行加成缩合聚合反应制得的桐油改性线型酚醛树脂，是国内我未见报导的桐油改性酚醛树脂新品种。用该树肥作为粘接制造的汽车摩擦材料的主要性能指标，均超过国家规定的标准。其中，刹车片衬片的缺口冲击强度平均达到了４．１１ｄＪ／ｃｍ＾２，离合器面片的弯曲强度平均达到了５４．４ＭＰａ，最大应变平均达到了９．２×１０＾－３ｍｍ／ｍｍ。对制品的     

聚醚砜酮薄膜热稳定性及热解动力学规律的研究

采用热重分析法对聚醚砜酮(PPESK)薄膜在氮气氛下的热分解反应进行了研究，结果表明，热分解反应最剧烈的温度区间在400℃～600℃之间，这也是热解炭化阶段的关键温度区间；温度高于600℃分解反应趋于缓和。动力学研究得出，PPESK分解过程为一级反应；以Kissinger最大失重速率法求得表观活化能为211．35kJ／mol；以Ozawa等失重百分率法求得10％～30％的失重率下反应表观活化能在152．31kJ／mol～274．43kJ／mol之间，频率因子1nA值在21．98min^-1-38．75min^-1之间，充分表明PPESK热稳定性很高，这也为炭化过程提供了重要动力学参数。     

桐油改性酚醛树脂的研究：固化特征及其动力学分析

利用ＩＲ、ＤＳＣ分析技术研究了桐没性酚醛树脂的固化过程及其动力学。实验结果表明，这类改性树脂的固化过程分为３个阶段：①在１００～１６０℃范围内出现一个复杂的挥发吸热峰；②在１５０～２４０℃范围内出现了一个宽广、平缓的固化放热峰；③在２４０～２６０℃范围内出现一个较小的第二固化峰。随着甲醛／苯酚摩尔比的增加，改性树脂的表观活化能降低，固化速率加快。在１６０～１８０℃下固化７～１５ｍｉｎ，这类改性树脂     

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.