改善减一线和减二线间的分离效果是增产裂解料的有效途径

根据燕化炼油厂1995年裂解料生产实际，借助Aspen Plus流程模拟软件，侧重模拟分析了减一线油利用上存在的问题，提出减一线和减二线的分离效果差是目前制约裂解料增产和炼厂经济效益的重要原因。通过对减压塔减一至减二段实施改造，可以使减一线直接产出较好的裂解料，而且减一线收率会有明显增加。     

Continuously chirped DFB gratings by specially bent waveguides fortunable lasers

We have implemented and studied a new type of tunable multiple-section semiconductor distributed feedback (DFB) laser using tailored chirped DFB gratings. Arbitrarily and continuously chirped DFB gratings are defined by bent waveguides on homogeneous grating fields with ultrahigh spatial precision. The mathematical bending functions are optimized in this case to provide enlarged wavelength tuning ranges. We present the results of model calculations, the technological device realization and experimental results of the DFB laser characterization e.g. a tuning range of 5.5 nm without wavelength gaps and high side mode suppression ratio     

ATM交换结构的成组输入排队模型

本文提出一种新的ATM交换排队结构——成组输入排队结构(GIQ),其基本思想是将输入端分组,同一组的输入端共享排队缓存。GIQ不仅能提高缓存的利用率和系统的吞吐率(达到96.2％),而且还能大大改善交换结构的抗突发能力。采用计算机仿真模拟的方法,分析了GIQ在均匀连续业务流和突发业务流下的性能,并与其它输入排队结构的性能进行了比较。     

分析恒载效应的有限元方法

本文在Takabatake关于恒载对梁静、动力影响的研究工作的基础上,导出了梁考虑恒载效应的动力分析有限元公式,提出了荷载影响刚度矩阵的概念。分析了分布和集中两种恒载型式对简支梁和悬臂梁自振特性的影响。计算结果表明,用本文方法与Takabatake应用Galerkin方法和近似闭合解方法的结果吻合良好。同时由于本文采用了矩阵形式,不仅便于编制计算机程序,且使方法有更广泛的适用性和灵活性,可更方便地用于各种不同的构造和边界条件下的实际结构。     

In-chain functionalization by alternating anionic copolymerization of styrene and 1-(4-dimethylaminophenyl)-1-phenylethylene

Anionic copolymerizations of styrene (M₁) with excess 1-(4-dimethyl-aminophenyl)-1-phenylethylene (M₂) were conducted in benzene at 25°C for 24h, using sec-butyllithium as initiator. Narrow molecular weight distribution copolymers with M?;_n = 16.1 × 10³ g/mol (M?_w/M?_n = 1.04) and 38.2 × 10³g/mol (M?_w/M?_n = 1.05), and 24 and 38 moles of M₂ per macromolecule, respectively, were characterized by size exclusion chromatography, ¹H NMR spectroscopy and DSC. The monomer reactivity ratio, r₁ = 5.6, was obtained from the copolymer composition at complete consumption of M₁, assuming that the rate constant k₂₂ =0,i.e. r₂ =0. The polymers exhibited T_g values of 128 and 119°C, respectively, which correspond to an estimated T_g = 217°C for the hypothetical homopolymer of M₂.     

含能材料分子结构与感度的相关性

综述了国外近年来含能材料分子结构参数与感度相关关系的最新研究成果。研究表明：某些芳香族硝基化合物的撞击感度与Ｃ－ＮＯ２键强度有关；硝胺及脂肪族硝基化合物的冲击波感度与分子中Ｎ－ＮＯ２键的数目，长度和分子量相关。     

方盒形带凸缘件的板料形状优化设计

本文用大变形刚塑性有限元模拟正方形板料在方冲头拉延下的凸缘变形过程，并以所获得的工件形状与金属流动方向为依据，对初始板料形状进行修正。对修正后的坯料形状进行二次模拟，获得了与给定凸缘形状基本吻合的拉延件形状。文中对不同凸缘圆角对极料优化形状的影响作了计算，讨论了在保证边界轮廓位置不变的条件下网格划分的方法。     

淀积条件对GDa—SiNx薄膜电学特性的影响

本文讨论了用辉光放电法制备氮化硅薄膜时衬底温度、射频功率和气体流量比对薄膜的电导率、介电常数和击穿强度的影响。通过优化生长条件，制备了优质非晶氮化硅薄膜，其介电常数为７．５、击穿强度为５．５ＭＶ／ｃｍ、电导率为１０－１３（Ωｃｍ）－１。     

Geological controls to the indoor radon distribution in southern Belgium

Soils and rocks are the predominant source of indoor radon (Rn) in southern Belgium. We have studied the correlations between geological features and indoor Rn concentrations using an indoor Rn data set of approx. 1700 short-term measurements. The sediments in the study region are divided into 11 geological series or 43 stages and 16 rock types. The results show a striking relation between indoor Rn concentration and the geological factors.