基于表面分析技术和铁谱技术的某重载履带车辆主离合器摩擦副失效机理研究

利用扫描电子显微镜、能量色散谱仪及铁谱仪分析了某重载履带车辆主离合器分离机构中的活动盘弹子槽的磨损失效机理.结果表明:磨损表面存在明显的犁沟痕迹和点蚀坑,而粘着磨损迹象不明显;铁谱分析结果表明润滑脂中的磨粒主要包括典型的粘着磨粒、接触疲劳磨粒和腐蚀磨粒;磨损表面的主要失效机制为磨料磨损、粘着磨损、接触疲劳磨损和腐蚀磨损的综合作用;采用联合表面分析技术和铁谱技术研究材料表面磨损失效机理具有一定的优越性.     

Preparation and characterization of optically active polymers containing pendent and terminal chiral units via atom transfer radical polymerization

Optically active homopolymers and copolymers, bearing chiral units at the side chain and end chain, were prepared via atom transfer radical polymerization (ATRP) techniques. The well‐defined optically active polymers were obtained via the ATRP of pregnenolone methacrylate (PR‐MA), β‐cholestanol acrylate (CH‐A), and 20‐(hydroxymethyl)‐pregna‐1,4‐dien‐3‐one acrylate (HPD‐A) with ethyl 2‐bromopropionate as the initiator and CuBr/N,N,N′,N″,N″‐pentamethyldiethylenetriamine as the catalytic system. The experimental results showed that the polymerizations of PR‐MA, CH‐A, and HPD‐A proceeded in a living fashion, providing pendent chiral group polymers with low molecular weight distributions and predetermined molecular weights that increased linearly with the monomer conversion. Furthermore, the copolymers poly(pregnenolone methacrylate)‐b‐poly[(dimethylamino)ethyl methacrylate] and poly(pregnenolone methacrylate‐co‐methyl methacrylate) were synthesized and characterized with ¹H NMR, transmission electron microscopy, and polarimetric analysis. In addition, when optically active initiators estrone 2‐bromopropionate and 20‐(hydroxymethyl)‐pregna‐1,4‐dien‐3‐one 2‐bromopropionate were used for ATRPs of methyl methacrylate and styrene, terminal optically active poly(methyl methacrylate) and polystyrene were obtained. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1502–1513, 2006     

光电经纬仪测量精度指标的确定

光电经纬仪测量元素误差是外弹道测量中最主要的误差源。为了保证外弹道的测量精度，就应对光电经纬仪的测量精度进行合理设计。通过数学解析的方法，推导建立了2个简洁的公式：1）单站定位体制下弹道点位精度和光电经纬仪测角、测距精度以及目标斜距、高角之间的数学表达式；2）对称交会测量体制下弹道点位精度和光电经纬仪测角精度以及目标斜距、交会角之间的数学表达式。这2个公式为光电经纬仪精度指标的设计论证提供了理论依据。     

Linear operators in finite dimensional probabilistic normed spaces

In this paper, we consider strongly bounded linear operators on a finite dimensional probabilistic normed space and define the topological isomorphism between probabilistic normed spaces. Then we prove that every finite dimensional probabilistic normed space which is a topological vector space is complete.     

X射线驻波及其应用

介绍了Ｘ射线驻波的产生原理、实验技术及其在表面和界面以及低维材料微结构探测等方面的应用新进展     

非紧致一秩对称空间Cartan运动群上的Radon变换

本文研究与非紧致一秩Riemann对称空间相应的Cartan运动群上的Radon变换,用Weyl分式积分求出了这种变换的逆,并用这种逆Radon变换导出Fourier代数中元素的局部正则性,最后证明了任一正则K-轨道不是Fourier代数的谱综合集。     

非紧致一秩对称空间上某种极大函数的可和性

ＮｏěｌＬｏｈｏｕé证明了复对称空间上某种极大函数ｆ＋（ｘ）＝ｓｕｐｔ＞０（１＋ｔ）３２｜Ｐｔｆ（ｘ）｜的可和性可归结为‖（Δ０）１２ｆ‖（ｘ）的可和性．作者证明了上述结果对奇数维实双曲空间成立．由于偶数维实双曲空间的热核表达式不同，因此有必要对偶数维实双曲空间的情形单独给出证明．本文的目的就是证明上述结果对偶数维实双曲空间亦成立．     

One pot synthesis of <Emphasis Type="Italic">N</Emphasis>-ethylaniline from nitrobenzene and ethanol

A novel method for the one pot synthesis of N-alkyl arylamines from nitro aromatic compounds and alcohols is proposed through the combination of the aqueous-phase reforming of alcohol for hydrogen production, the reduction of nitro aromatic compounds for the synthesis of aromatic amine and the N-alkylation of aromatic amine for the production of N-alkyl arylamine over an identical catalyst under the same conditions of temperature and pressure in a single reactor. In this process, hydrogen generated from the aqueous-phase reforming of alcohols was used in-situ for the hydrogenation of nitro aromatic compounds for aromatic amine synthesis, followed by N-alkylation of aromatic amine with alcohols to form the corresponding N-alkyl arylamines at a low partial pressure of hydrogen. For the system composed of nitrobenzene and ethanol, under the conditions of 413 K and P _N2 = 1 MPa, the conversion degrees of nitrobenzene and aniline were 100%, the selectivity to N-ethylaniline and N, N-diethylaniline were 85.9% and 0%–4%, respectivity, after reaction for 8 h at the volumetric ratio of nitrobenzene:ethanol:water = 10:60:0. The selectivity for N, N-diethylaniline production is much lower than that through the traditional method. In this process, hydrogen and aromatic amines generated from the aqueous-phase reforming of alcohols and hydrogenation of nitro aromatic compounds, respectively, could be promptly removed from the surface of the catalyst due to the occurrence of in-situ hydrogenation and N-alkylation reactions. Thus, this may be a potential approach to increase the selectivity to N-alkyl arylamine. Supported by the Program for New Century Excellent Talents in University (Grant No. NCET-04-0557), and the Specialized Research Fund for the Doctoral Program of High Education (Grant No. SRFDP-20060337001)     

无穷维动力系统

本文简要介绍了无穷维动力系统研究中的一些重要问题。     

DIAGONAL REDUCTION OVER sπr IDEALS

This article introduces a new class of ideals, namely, the sπr ideals. It is shown that every regular square matrix over sπr ideals of a ring admits a diagonal reduction.