用于生产甲基丙烯酸的杂多酸催化剂的研究

以异丁烯为原料的两段直接氧化生产甲基丙烯酸最新工艺有许多优点。其技术关键在于研制出高效的甲基丙烯醛选择性氧化催化剂。本文报道P-Mo-As-Cu杂多化合物催化剂的组成、制备条件对催化剂活性的影响。经优化后获得高选择性、高活性的二段氧化催化剂，其甲基丙烯酸收率达60％以上。     

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本文通过对在用钻机井架的现场实际测试,建立数据库、测评模型,对实测的数据用计算机技术进行分析,提出了初始弯曲应力;数据正态分布检验——x～2检验;建立回归方程;在给定置信度下测评当前承载能力的技术概念。解决了在用钻机A型井架的安全性评估问题,是一种较为合理、可靠、科学的测评技术和方法。     

Inter- and intra-molecular ionic interactions of polyampholyte: Carboxymethyl-2-diethylaminoethylcellulose

Carboxymethyl-2-diethylaminoethylcellulose (CM-DEAE cellulose) was prepared by etherification of carboxymethylcellulose with diethylaminoethyl chloride in a NaOH solution. The behaviour of CM-DEAE cellulose in aqueous solution was studied by viscosity and GPC measurements. The degree of substitution (DS) and existing states of DEAE substituents were examined by the use of proton NMR, and those of the CM substituents were observed with FT-IR. The results reveal that the reduced viscosity and apparent molecular size of CM-DEAE cellulose vary with the concentration of sodium chloride and changes in pH and DS. These phenomena can be explained in terms of inter- and intra-molecular ionic interactions.     

Crystallization behaviour of Ni-Co-base metallic glasses by isochronal and isothermal annealing

The crystallization behaviour of three amorphous alloys, Co₅₀Ni₂₅Si₁₅B₁₀, Ni₅₀Co₂₅Si₁₅B₁₀ and Ni₅₀Co₂₅P₁₅B₁₀, was studied by means of differential thermal analysis in conjunction with scanning transmission electron microscopy. Isochronal annealing showed a strong dependence of crystallization on scan rate over the range of 1.99 to 20.70 K min^–1. At high Co/Ni ratios, a sequential two-stage crystallization process involving primary MS-I phase followed by MS-II phase precipitation was observed. At low Co/Ni ratios MS-I and MS-II crystallization were concurrent and inseparable. Replacement of the metalloid Si with P as the glass-former dramatically reduced the activation energy for crystallization as well as the crystallization temperature. A mechanistic understanding of these findings was pursued in light of TEM/STEM microanalysis     

有扰对称信道平均信息量的计算

照相手机让诺基亚抢了风头，这真是亚洲人的失策。在日本和韩国，内置摄像头的手机早就不是什么值得炫耀的东西了。不过日本人的动作还是很快的，GD88和N8一副后来居上的架势，让人不敢小瞧。     

高含硫钻井液缓蚀剂的合成及性能研究

本文合成了抑制H₂S腐蚀的咪唑啉类缓蚀剂,并研究了它们的性能。正交试验表明,最佳合成条件是:反应温度:190～200℃;酸:胺(mol比)=1:1.05;反应时间以3～5小时为宜。根据以上条件合成的缓蚀剂,在含有3200mg/lH₂S的泥浆中,用量为0.2%时,抑制效果能达到80～90%,与碱式碳酸锌复配使用时,能提高缓蚀效率和降低碱式碳酸锌的用量,并发现缓蚀剂与CaO之间具有明显的协同效应。泥浆流变性能试验表明,缓蚀剂能提高泥浆的动切力和动塑比,对失水量影响不大。此外,利用X-射线衍射试验证明:(1)低碳钢在含H₂S的泥浆中,腐蚀产物的主要组成为Fe₉S₆;(2)H₂S会破坏FCLS的稳定性,分解出Fe²⁺,与H₂S反应生成面心立方的Fe₂S₄。     

Exploratory analysis of brain connectivity with ICA.

Covariance-based methods of exploration of functional connectivity of the brain from functional magnetic resonance imaging (fMRI) experiments, such as principal component analysis (PCA) and structural equation modeling (SEM), require a priori knowledge such as an anatomical model to infer functional connectivity. In this research, a hybrid method, combining independent component analysis (ICA) and SEM, which is capable of deriving functional connectivity in an exploratory manner without the need of a prior model is introduced. The spatial ICA (SICA) derives independent neural systems or sources involved in task-related brain activation, while an automated method based on the SEM finds the structure of the connectivity among the elements in independent neural systems. Unlike second-order approaches used in earlier studies, the task-related neural systems derived from the ICA provide brain connectivity in the complete statistical sense. The use and efficacy of this approach is illustrated on two fMRI datasets obtained from a visual task and a language reading task.     

论GPS星座组成及若干抗AS方案

本文首先讨论GPS星座组成及美国的用政策，阐述了AS措施及其对GPS测量的影响。然后，对抗AS的若干方案进行介绍，分别对平方法、互相关法、码相关干法及P－W技术（Ashtech法）进行叙述和评论，指出它们的优缺点，评述它们在GPS技术发展过程所起的作用。最后，对GPS星座建成后的形势作了小结，并对当前我国GPS事业的有关问题提出四点建议。