聚硅烷的热分解动力学研究

用热重法（ＴＧＡ）研究了聚（甲基环己基硅烷）、甲基环己基硅烷与甲基苯乙基硅烷共聚物和聚（甲基苯乙基硅烷）的热分解动力学，计算了热分解动力学参数。结果表明，其热分解活化能分别为２０８ｋＪ／ｍｏｌ、１８７ｋＪ／ｍｏｌ和１１４ｋＪ／ｍｏｌ；这３者的热分解均符合无规引发裂解模型。     

高分辨裂解气相色谱—质谱研究聚吡咙的热分解

用高分辨裂解气相色谱－质谱考察了不同聚吡咙的热分解，分析了其热分解产物的组成，分布和归属，研究了其环化过程以及该过程对热分解的影响，进而详细阐述了聚吡咙的热分解机理。     

聚合反应对共聚甲醛不稳定末端基的影响研究

研究了聚甲醛生产过程中的反应温度、引发剂三氟化硼用量、反应物配合比、反应物二氧五环添加方式及聚合方式等对聚甲醛不稳定末端基(HO)的影响,研究结果表明,在反应温度为89℃,引发剂用量为50×10~(-6),采用引发剂与二氧五环单体先期聚合条件下,不稳定末端基含量最低,为0.86%,此时聚甲醛的热稳定性最好,初始热分解温度为314℃,二氧五环的加入,能够有效地提高聚甲醛分子链的热稳定性,减少不稳定末端基,聚甲醛不稳定末端基对聚甲醛的热分解温度具有较大影响,随着不稳定末端基的升高,聚甲醛的热分解温度随之降低,热稳定性下降;经过对反应条件研究优化后,聚甲醛的热分解温度比原先提高了25℃。     

高分辨裂解气相色谱－质谱研究聚吡咙的热分解

用高分辨裂解气相色谱－质谱考察了不同聚吡咙的热分解，分析了其热分解产物的组成、分布和归属，研究了其环化过程以及该过程对热分解的影响，进而详细阐述了聚吡咙的热分解机理。     

硝铵炸药生产中恶性事故的防范

文章分析了硝铵炸药生产中的火灾和爆炸事故，认为硝铵混合物在高温条件下的热分解是引发这类恶性事故的主要原因，该文还给出了硝酸铵分解的要点，并提出预防事故的措施。     

石油醚对乳化炸药基质热分解动力学的影响

采用TG-DSC联用技术对混有石油醚的乳化基质样品的热分解动力学进行了研究,用Ozawa法和Satava-Sestak法对试验数据进行处理,得到各样品的动力学参数和机理函数.讨论了混入石油醚后乳化基质热分解动力学参数变化的原因,认为石油醚的加入会改变乳化基质的热分解动力学行为,具有促进乳化基质热分解的趋势.     

KH—304热固性聚酰亚胺树脂及其碳纤维复合材料高温热稳定性的研究

用热重分析仪分析了ＫＨ－３０４热固性聚酰亚胺树脂及其碳纤维复合材料在氮气和空气中的热分解过程，计算了它们在氮气和空气中的热分解活化能，比较了两者的高温热稳定性。     

KH－304热固性聚酰亚胺树脂及其碳纤维复合材料高温热稳定性的研究

用热重分析仪分析了ＫＨ－３０４热固性聚酰亚胺树脂及其碳纤维复合材料在氮气和空气中的热分解过程，计算了它们在氮气和空气中的热分解活化能，比较了两者的高温热稳定性。     

酚改性二甲苯甲醛树脂的热分解动力学

用热重法(TGA)分析了酚改性二甲苯甲醛(XF)树脂的热分解过程。运用Ozawa和Kissinger法进行动力学研究,得到其热分解活化能。结果表明:与普通线性酚醛树脂相比,苯酚改性XF树脂和双酚A改性XF树脂这两种改性树脂在热分解过程中的活化能都高,热分解温度也较高,热失重率降低;其中双酚A改性XF树脂的热分解活化能和热分解温度最高,热失重率最低;这说明双酚A改性XF树脂具有优异的耐热性能。     

聚偶氮酰胺热分解性的研究

本文研究了利用Ritter(里特)腈和碳正离子加成方法合成的新型大分子引发剂聚偶氮酰胺PPA(Ⅰ)、PPA(Ⅱ)的热分解行为。结果表明,它们是高活性、低引发效率的引发剂,不具备合成嵌段共聚物的引发剂特性。     

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.