复掺钢丝绒纤维/水镁石纤维沥青胶浆性能研究

通过改变纤维总掺量和两种纤维的体积比,采用廷度试验、锥入度试验、布氏旋转粘度试验和动态剪切流变试验研究了混杂纤维沥青胶浆的低温延展性能、抗剪切性能、粘度特性及高温流变特性,同时借助扫描电镜(SEM)对其试样断面进行观察分析.结果表明:沥青胶浆的低温延展性随纤维掺量的增大而降低;在6％纤维总掺量范围内,随着纤维掺量的增大粘度逐渐增大,且增大的幅度减小;当钢丝绒纤维与水镁石纤维体积比为6/4时,沥青胶浆的车辙因子(G*/sinδ)、抗剪强度达烈最佳值;将两种纤维混杂掺入沥青胶浆中,充分分散,其与沥青粘结良好,发挥了增粘和桥接作用,提高了沥青胶浆的整体稳定性和抵抗永久变形的能力.     

复掺钢丝绒纤维/水镁石纤维沥青胶浆性能研究

通过改变纤维总掺量和两种纤维的体积比,采用延度试验、锥入度试验、布氏旋转粘度试验和动态剪切流变试验研究了混杂纤维沥青胶浆的低温延展性能、抗剪切性能、粘度特性及高温流变特性,同时借助扫描电镜(SEM)对其试样断面进行观察分析。结果表明:沥青胶浆的低温延展性随纤维掺量的增大而降低;在6%纤维总掺量范围内,随着纤维掺量的增大粘度逐渐增大,且增大的幅度减小;当钢丝绒纤维与水镁石纤维体积比为6/4时,沥青胶浆的车辙因子(G*/sinδ)、抗剪强度达到最佳值;将两种纤维混杂掺入沥青胶浆中,充分分散,其与沥青粘结良好,发挥了增粘和桥接作用,提高了沥青胶浆的整体稳定性和抵抗永久变形的能力。     

矿粉对沥青胶浆流变性能影响及微观分析

为探究矿粉对沥青胶浆流变特性的影响规律,采用动态剪切流变仪分别对四种矿粉组成的沥青胶浆进行了不同加载模式下的流变试验,采用低温弯曲梁流变仪对胶浆进行低温小梁弯曲试验,分析了粉胶比、温度、荷载频率对沥青胶浆高低温流变特征参数的影响。借助X射线衍射(XRD)和扫描电镜(SEM),测试矿粉岩性特征和胶浆的微观形貌。结果表明:花岗岩矿粉对胶浆的增效行为最强,石灰岩胶浆的高低温性能最佳;矿粉的比表面积对胶浆的流变性能影响大于其矿料酸碱性组分对胶浆的流变性能影响;随着粉胶比的增加,沥青胶浆的复数剪切模量随之增加,但相位角变化微小;推荐四种胶浆的合理粉胶比为1.2;最佳粉胶比状态下,胶浆微观界面粘结状况最好。研究结果可为不同种类的填料在沥青路面的应用提供技术指导和理论支撑。     

泡沫温拌沥青胶浆的流变特性及微观机制分析

为了全面探究泡沫温拌沥青(以下简称泡沫沥青)胶浆的流变特性,分别针对不同粉胶比的泡沫沥青胶浆进行温度和频率两种扫描模式下的动态剪切流变(DSR)和弯曲梁流变(BBR)试验,分析了粉胶比对泡沫沥青胶浆高、低温性能的影响,利用van Gurp Palmen(vGP)图分析了泡沫沥青胶浆时温等效原理的有效性,基于此建立了泡沫沥青胶浆在频率扫描模式下的主曲线,并运用此主曲线分析了其在较宽的温度和频域下的流变特性。此外,通过扫描电子显微镜(SEM)的微观结构识别和差示扫描量热(DSC)的热特性测试分析了泡沫沥青胶浆的微观机制。结果表明:矿粉的添加对泡沫沥青的高、低温性能均有显著影响,随着粉胶比的增大,泡沫沥青胶浆的高温性能逐渐增强,低温性能逐渐降低;泡沫沥青胶浆适用于时温等效原理,在较宽的温度域及频率域内,泡沫沥青胶浆较基质沥青胶浆具有更优的高温性能。此外,泡沫沥青胶浆与基质沥青胶浆的低温等级温度基本一致;泡沫沥青胶浆中矿粉的分散性优于基质沥青胶浆中矿粉的分散性,且泡沫沥青胶浆中含有更多的微孔洞;基质沥青较泡沫沥青具有更好的热稳定性,但在相同的粉胶比下,泡沫沥青胶浆较基质沥青胶浆具有更好的热稳定性;粉胶比不大于1.0时,泡沫沥青胶浆较基质沥青胶浆具有更高的玻璃化转变温度。综合流变特性及微观机制分析得到泡沫沥青胶浆的粉胶比不宜大于1.0。     

活化煤矸石改性沥青胶浆粉胶比确定及粘温特性研究

煤矸石是我国目前排放量最大的工业固体废弃物之一,但鲜见其活化以改善沥青性能的研究成果.采用动态剪切流变仪(DSR)、弯曲梁流变仪(BBR)和布氏粘度仪(BV)对活化煤矸石改性沥青胶浆的流变特性进行测试,分析了重复蠕变劲度的粘性部分Eμ和蠕变劲度模量S与粉胶比之间的关系,通过流变学手段及双直线简化模型,得到活化煤矸石改性沥青胶浆的合理粉胶比范围及最佳粉胶比;借助扫描电镜(SEM)和红外光谱试验仪(IR)对其作用机理进行分析.研究结果表明,确定出的活化煤矸石改性沥青胶浆粉胶比能较好地平衡沥青胶浆的高低温性能;活化煤矸石可有效改善沥青胶浆的温度敏感性,其改性沥青胶浆粘温特性的效果较矿粉更为显著;平均粒径小、比表面积大及表面多孔层状结构是主要原因.研究成果为拓宽固体废弃物煤矸石在沥青路面工程中的资源化利用途径提供了依据.     

活化煤矸石改性沥青胶浆粉胶比确定及粘温特性研究

煤矸石是我国目前排放量最大的工业固体废弃物之一,但鲜见其活化以改善沥青性能的研究成果。采用动态剪切流变仪(DSR)、弯曲梁流变仪(BBR)和布氏粘度仪(BV)对活化煤矸石改性沥青胶浆的流变特性进行测试,分析了重复蠕变劲度的粘性部分Eμ和蠕变劲度模量S与粉胶比之间的关系,通过流变学手段及双直线简化模型,得到活化煤矸石改性沥青胶浆的合理粉胶比范围及最佳粉胶比;借助扫描电镜(SEM)和红外光谱试验仪(IR)对其作用机理进行分析。研究结果表明,确定出的活化煤矸石改性沥青胶浆粉胶比能较好地平衡沥青胶浆的高低温性能;活化煤矸石可有效改善沥青胶浆的温度敏感性,其改性沥青胶浆粘温特性的效果较矿粉更为显著;平均粒径小、比表面积大及表面多孔层状结构是主要原因。研究成果为拓宽固体废弃物煤矸石在沥青路面工程中的资源化利用途径提供了依据。     

活化煤矸石改性沥青胶浆流变性能实验研究

煤矸石是我国目前排放量最大的工业固体废弃物之一,以粉体煤矸石为填料对沥青进行改性在国内外鲜有研究涉及。采用锥入度实验、动态剪切流变实验(DSR)和弯曲梁流变实验(BBR),研究了不同粉胶比条件下活化煤矸石改性沥青胶浆的剪切强度及高、低温流变性能变化规律,并与矿粉改性沥青胶浆进行对比;在此基础上,初探了活化煤矸石改性沥青胶浆作用机理。结果表明,采用活化煤矸石替代矿粉后,沥青胶浆的抗剪强度和高温性能大幅提高,低温性能则基本相当。研究成果为活化煤矸石替代矿粉作为沥青混合料填料的可行性提供了依据。     

PEG/SiO_2相变颗粒对沥青胶浆性能实验研究

利用相变材料在相变过程中吸收或释放大量热量而保持温度不变的特性,用溶胶-凝胶法制备了聚乙二醇(PEG)/SiO_2相变颗粒,并分别以不同比例的PEG/SiO_2相变颗粒等体积代替矿粉,对沥青胶浆做针入度、软化点、动态剪切流变等实验,研究相变颗粒代替矿粉后对沥青胶浆常温及高温流变性能的影响。结果表明,以一定比例的相变材料替代矿粉可有效地改善沥青胶浆的高温性能,但对常温性能改善效果不明显。     

填料对橡胶沥青胶浆高低温性能的影响

为研究填料对橡胶沥青胶浆高低温性能的影响,选取矿粉和水泥作为填料,制备不同粉胶比(矿粉为0.25,0.4,0.6和0.8;水泥为0.4,0.6)的橡胶沥青胶浆。通过蠕变恢复实验和弯曲梁流变实验对橡胶沥青胶浆的高温性能和低温性能进行研究。结果表明,随着粉胶比的增加,矿粉和水泥均能使橡胶沥青胶浆的高温性能得到提高,并且矿粉比水泥的改善效果好;随着粉胶比的增加,矿粉橡胶沥青胶浆和水泥橡胶沥青胶浆的低温性能均逐渐降低,在低温-12和-18℃时,矿粉使橡胶沥青胶浆的低温性能降幅更大。为了均衡橡胶沥青胶浆的高低温性能,矿粉橡胶沥青胶浆的最佳粉胶比范围宜为0.4~0.6。     

矿粉性能及其对浇注式沥青胶浆高温性能的影响分析

浇注式沥青混合料的矿粉含量较高，0.075 mm筛孔通过率为20%～30%,为满足混合料施工流动性而确定矿粉用量后，可提高其高温稳定性的措施除了沥青结合料，主要取决于矿粉的质量。通过六种矿粉样本的性能测试，并与浇注式沥青混合料常用的聚合物复合改性沥青配制沥青胶浆，进行200℃旋转黏度及60～95℃的动态剪切流变试验。基于随机森林法，对与沥青胶浆性能相关的矿粉关键性能指标影响程度进行分析，并建立两者之间的相关性，最后采用遗传算法，确定了沥青胶浆性能在较优条件下的沥青和矿粉关键指标组合取值范围。结果表明，同为石灰岩磨制的矿粉，化学组成差异较大，其塑性指数、细度及比表面积有一定的相关性，并与SiO₂含量成为矿粉性能的四项关键指标，其中比表面积对沥青胶浆的车辙因子及黏度影响最大；当聚合物复合改性沥青的指标软化点为113～117℃、针入度为20.3～21(0.1 mm)、黏度为87 3.9～893.7 MPa·s时，矿粉的比表面积控制在1.7～1.8 m²/g、细度D50控制在10～12μm、塑性指数控制在2.6～5、SiO₂含量...     

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