论复合型表面裂纹准则

本文用理论和试验分析相结合的方法研讨了作者和前人先后提出的表面裂纹复合型断裂准则[G]max、[S]min、[σ_θ]max、[U_v]max、[σ_α]max和[r_p]max六个准则;再次证明了后三个准则优于前三准则;实测出了表面裂纹最深点的起裂角和临界起裂载荷随表面裂纹倾斜角的变化规律;最后指出了断裂准则中断裂参数应建立在相同的力学基准上,从而为工程应用和理论研究提供了可靠的依据。     

全动型变焦距照相物镜的象差优化设计

本文阐述了在微型机上进行全动型变焦距照相物镜优化设计的工作。提出了一种隐含函数控制方法,并对选择间隔作为变量参与优化过程进行了分析,在IBM-PC/XT微型机上编制了该变焦系统的优化设计程序,并以三组元全动型变焦距照相物镜f38～105为例进行了优化设计,结果证明该程序是可行和有效的。     

Preparation of isotropic submicron spherical boron nitride particles by restricted template method

Hexagonal boron nitride (h-BN) has received considerable attention, due to its high thermal conductivity and electrical insulation. However, the intrinsic platelike structure with the strong anisotropic property restricts its applications, and it is necessary to synthesize isotropic spherical h-BN particles (SP-BNs) with submicron size. Till now, methods to prepare (SP-BN) still exist problems, such as high oxygen impurities and pollution, generated by the ammonia and pyrolysis of precursors. Here, a relatively green reaction between the restricted template of carbon nanospheres and boron trioxide (B₂O₃) under elevated temperature is conducted, and the SP-BNs with an average diameter of 200–300 nm (named Nano-BN-s) have been successfully synthesized. Comprehensive scanning electron microscopy, transmission electron microscopy, and X-ray diffraction characterizations confirm the obtained products are spherical boron nitride. With the analysis of X-ray photoelectron spectroscopy and Fourier transform infrared, the reaction mechanism is briefly discussed. These results indicate the reaction occurs on the restricted template of carbon nanospheres, and the C atoms are substituted by B and N atoms as the reaction progress, forming the Nano-BN-s. What is more, the restricted template method plays a key role in the design and improves h-BN-based materials in the future and may also be extended to form other novel materials.     

Synthesis and evaluation of epoxidized vegetable oleic acid as a novel environmental benign plasticizer for polyvinyl chloride

A bio-based plasticizers, acetyl-oleate triethylene glycol (AOT), was successfully synthesized by using oleic acid as a raw material through esterification, epoxidation, and acetylation. Its structure was analyzed by Fourier transform infrared spectroscopy and ¹H nuclear magnetic resonance. The plasticizing performances of this plasticizer was compared with those of two commercial ones: dioctyl terephthalate (DOTP) and dioctyl adipate (DOA). This was done by blending these plasticizers with PVC, respectively. Thermal gravimetric analysis results showed that the 5% weight loss temperature of PVC with AOT was 53°C higher than that of DOA and 36°C higher than that of DOTP. The tensile results showed that the AOT plasticized PVC had excellent stretchability: its elongation at break with 50 phr AOT reached 697.7%. Furthermore, its transmittance was as high as 90%, showing better compatibility of ATO with PVC.     

Crystallization behavior of PHA/PEDEA oligoester blends

The crystallization behavior of oligoester blends prepared from crystalline poly(hexanediol adipate) (PHA) and amorphous poly(ethylene diethylene glycol adipate) (PEDEA) was studied using POM, WAXD, and DSC. The crystal form of both PHA and the blends are spherulites. The crystallinity, melting enthalpies, and crystallization rate increased with increased PHA content in the blends. Two sharp diffraction peaks of each blend were detected at the same position, where, respectively, 2θ = 21.3° and 24.1°. The research on the crystallization kinetics showed that the Avrami exponent of all the oligoester blends is approximately 4. It was demonstrated that the crystallization mechanism of PHA is not disturbed by amorphous PEDEA. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1363–1368, 2002; DOI 10.1002/app.10268     

高氯酸铵的催化热分解

用热分析技术研究了不同压力下几种多元催化剂或含能催化剂对AP热分解的影响，所研究的三种催化剂对AP高温分争的影响与粒度无关；从催化分解动力学参数解释了常压或低压与高压下的催化分解有不同的机理，推进剂燃速压力指数与AP高，低压下催化分解速率的不同有关。     

稀土催化剂的应用

稀土氧化物或稀土复合氧化物加入普通催化剂中 ,使催化剂具有优良的活性 ,本文从稀土催化剂在石油工业、高分子合成、氨合成、汽车尾气净化、橡胶合成、有机合成以及稀土固体超强酸在酯类合成中的应用等几个方面进行了阐述     

基于计算机测控技术的转矩流变仪的研制

介绍了基于计算机测控技术的聚合物转矩流变仪的研制，该仪器具有优良的性能指标，强大的数据文件处理能力、测试功能扩展能力，是高分子材料研究和开发的理想工具。     

星型聚合物破乳剂的合成与性能研究

采用“发散法”合成了以乙二胺为核心 1 0～ 3 0代的系列星型聚合物—聚酰胺 -胺(PAMAM)。采用IR、NMR和端基分析等手段对PAMAM的结构进行了表征并考察了这类聚合物对O/W型模拟原油乳液的破乳性能。结果表明 :随着支化代的增加 ,破乳性能提高。在 4 5℃、添加量为 15 0mg/L、90min的条件下 ,3 0代产品的破乳率达到 98 5 %。     

浅除盐水技术在合成氨水处理工艺中的应用

在合成氨生产过程中，要根据不同的工序要求对用水进行净化处理，很多合成氨生产厂尤其中小合成氨厂的水处理主要采用仅除去硬度的软化水作为一般蒸气锅炉给水和工艺用水。有自备电站的成氨厂锅炉炉水一般采用一级复床除盐水系统制备除盐水（电导率≤１０μｓ／ｃｍ） 工艺软化水制造成本低但其仅除去原水中的硬度而盐分没有减少，作为锅炉给水造成锅炉排污量大热损失大作为工艺用水常引起合成系统变换催化剂的表面结垢等门题，除盐水的水质好，能完全满足合成氨生产工艺用水的需要，但其制造成本为工艺水的几倍。本文主要介绍浅除盐水技术…