高频脉冲微束等离子电弧温度场的测试及分析

本文首次采用单波长激光干涉技术，对恒定直流和高频脉冲电流微束等离子电弧温度场进行了测试，并做了分析比较。以电弧温度分布为基础分析了高频脉冲电流微束等离子电弧收缩、稳定的原因。     

汛期采金船的缆绳牵拉

本文介绍了采金船渡汛时的停泊方向及采金船在洪水中可能产生拖曳力的估算方法，为了防止采金船汛期发生溜船事故，建议采用缆绳牵拉固船的措施，以保障采金船的汛期安全。     

Predicting the shape of organic crystals grown from polar solvents

A method for predicting the shape of organic crystals grown from polar solvents is presented. The model is an improvement of the recent method developed by Winn and Doherty (A.I.Ch.E. Journal 44 (1998) 2501) for predicting the shape of organic crystals grown from solvents in which the energy of adhesion at the interfaces is dominated by dispersive forces (e.g., non-polar solvents). The principal characteristic of the new method is that it can account for the role of hydrogen donor and hydrogen acceptor atoms in forming strong bonds at the interface. This technique is a first step towards predicting the shapes of organic crystals grown from polar solvents, and has been applied successfully to predict the shape of adipic acid grown from water, and succinic acid grown from water and from propanol.     

焊铝合金用IGBT交流矩形波弧焊逆变器

本文介绍了新型开关元件ＩＧＢＴ管作为逆变开关元件的交流矩形波逆变器的原理。并通过实验证明，该电源具有良好的引弧和稳弧性能，在铝合金焊接方面具有较好的工艺性能。     

Suitable test structures for submicron ion beam analysis

For the precise determination of the sizes of submicron beam spots test structures with an excellent edge definition are required. For this purpose a semiconductor heterostructure consisting of an 1.62 μm GaInP epi-layer grown on (0 0 1) GaAs has been made, which provides atomically sharp edges for beam spot size measurements. Since the sample has been thinned down by standard transmission electron microscope (TEM) preparation techniques, it can be used for both PIXE and STIM. The sample has been investigated with a TEM and the ion nanoprobe LIPSION. A one-dimensional beam profile in the low current mode was determined by a STIM measurement using 2 MeV protons and yielded a FWHM of (41±4) nm, which is the smallest value reported so far for high energy nuclear micro- and nanoprobes. Furthermore we present nickel nanowhiskers produced at the GSI Darmstadt by electrochemical preparation of etched ion track membranes that have been used to obtain two-dimensional images of the shapes of submicron beam spots. For these measurements a scan over a single nickel nanowhisker having a diameter of 220 nm and a height of about 6 μm was performed.     

提高20t电弧炉炉衬寿命工艺实践

炉渣碱度、泡沫渣高度、吹氧角度、补炉方式等是影响20t电弧炉炉衬寿命的主要因素。为了提高炉衬寿命,莱钢炼钢厂采取了控制炉渣组成、泡沫渣全程埋弧操作、吹氧、喷补炉衬等多项措施,使炉衬寿命稳定在600炉次以上。     

Quantity,controls and functions of large woody debris in Midwestern USA streams

Large woody debris (LWD) can increase stream habitat heterogeneity by providing structure, altering flow patterns, enhancing sediment deposition, forming pools and retaining organic matter. In North America, the role of LWD has been studied extensively in streams of mature forests (e.g. Pacific Northwest), but few studies have assessed LWD in streams of younger forests (e.g. Midwestern USA). Our objectives were to: (1) quantify the volume and abundance of LWD in a set of Midwestern streams; (2) evaluate possible factors influencing LWD quantity; (3) identify the functional roles of LWD; and (4) compare LWD levels in the upper Midwest to those elsewhere in North America. In 2002 and 2003, we measured LWD and geomorphological variables in 15 low‐gradient streams draining previously logged watersheds in the Upper Peninsula of Michigan. Mean (±SE) LWD volume (0.77 ± 0.12 m³ 100 m⁻²) and abundance (33 ± 3 pieces 100 m⁻¹) were 71% and 10% lesser, respectively, than in streams of similar gradient elsewhere in North America. Channel shape (width:depth ratio) explained 30% of the variation in LWD volume (multiple stepwise regression, P = 0.015) while LWD length and length:channel width combined, explained 72% of the variation in LWD density (multiple stepwise regression, P < 0.0001). About 50% of the LWD either stored sediment or stabilized banks and 14% of the LWD formed pools, although pool density was not significantly related to LWD volume or density. LWD levels, overall, were low in upper Midwestern streams, but the relative importance of that LWD to ecosystem function may be magnified in these wood‐poor systems. Copyright © 2006 John Wiley & Sons, Ltd.     

异形柱框架结构设计方法分析与参数控制

近年来,异形柱框架结构(框轻结构体系),因其能较好地满足建筑使用上和结构性能上的要求,而逐步得到了推广应用,并被列为建设部首批住宅建设新技术推荐目录。但异形柱框架结构设计目前还没有可依据使用的国家标准和行业标准。本文根据对江苏省地方标准《钢筋混凝土异形柱框架结构技术规程》(DB32/512-2002)的理解,结合笔者设计实践经验,提出个人看法,供同行参考。     

工程结构优化设计发展综述

 着重评述了工程结构优化设计研究领域从最初的尺寸优化发展到形状优化、拓扑优化的基本历程及其相关特点，并对优化设计选用的优化算法进行了归类，提出了这一领域今后仍然有待于发展的主要方面．     

电熔氧化镁炉弧压系数与弧流系数的测定

在实际测试的基础上，给出了电熔镁炉的弧压系数和弧流系数，为进一步研究电熔镁炉提供依据。