多领域优化设计中耦合因素的一种协调方法

由多领域组成的大系统协同优化设计中 ,主要存在两类耦合因素 :一是多个领域都需要对其进行优化设计的变量 ,即系统变量或交叉变量 ;二是某个领域计算的结果作为另一个领域的输入 ,即相关变量或耦合变量。这些耦合因素的存在 ,导致整个系统求解的过程出现混乱和无序。本文根据二级求解技术 ,通过引入一些辅助变量 ,提出一种处理这些耦合因素的方法 ,并给出一个简单算例阐述方法的实现     

ICP-AES法测定GH3128合金中硅、锰、钨、钼、铬、钛、铝、铁和锆等元素

采用ICP-AES法测定GH3128合金中硅、锰、钨、钼、铬、钛、铝、铁、锆等多种合金元素。系统研究了各元素4条分析谱线的光谱干扰情况,根据光谱干扰研究结果和分析谱线的灵敏度、信背比以及等效离子浓度等进行了分析线的选择。采用柠檬酸络合钨,基体匹配法消除共存元素干扰,效果良好。     

Metal-on-metal bearings surfaces: materials, manufacture, design, optimization, and alternatives

When first introduced, total hip replacements offered pain relief and improved mobility in elderly patients. The success of this procedure in terms of long-term durability and restoration of function has led to its use in younger, more active patients. This has resulted in a commensurate increase in patient expectation regarding longevity and the degree to which function and lifestyle is restored. The bearing surface is a key feature of the performance of replacement joints. It is generally accepted that excessive amounts of wear debris preclude their long-term survivorship and hence there is an ongoing requirement for bearing surfaces which minimize debris generation. The purpose of this paper is to review the factors which affect the performance of so-called metal-on-metal bearings, to compare their performance with that of the other commonly used contemporary alternatives, metal and ceramic articulating against highly cross-linked polyethylene, and ceramic-on-ceramic, and finally to consider the potential solutions offered by new developments such as ceramic-on-metal and coatings applied to metal-on-metal bearings.     

冷却塔专用水轮机的数值模拟与性能研究

以冷却塔内额定流量为0.833 m³/s的双级贯流式水轮机为研究对象,基于ANSYS-Workbench操作平台对其进行单向流固耦合分析。采用三维建模软件UG,建立水轮机模型。使用商业CFD软件Fluent,对全流道模型进行三维定常湍流数值模拟,分析了内部流场及各部件的水力损失,得到了转轮叶片上准确的水压力分布。将流场计算结果应用到结构场中,使用有限元分析软件ANSYS,对转轮设计工况下的刚强度进行了计算,得到了转轮的静应力分布和变形情况。     

ICP-AES法测定碳钢、低合金钢中13种元素

本文选择了硝酸、王水、逆王水,进行碳钢、低合金钢溶样条件试验,以谱线强度为指标,溶解酸种类、溶解酸浓度、溶解酸用量、定容酸用量等四因素为变化条件,各因素中有三水平,即按正交实验表L_9(3~4)进行试验,编制计算程序,快速、科学地优选出最佳溶样条件—30ml NHO_3(1+5v/v)和3ml HCl,ICP-AES法同时测定铝、砷、铬、钴、铜、磷、锰、钼、镍、硅、锡、钛和钒13种元素。为确定测试方法的重复性(r)和再现性(R)而进行精密度试验。精密度数据是由10个实验室对7个样品作试验确定的。方法的回收率为94％-105％。精密度在8％以内。     

HPLC Columns,Theory, Technology,and Practice

ABSTRACT

This paper presents some results of experimental research addressing the influence of different thermal insulation fillings on dynamic properties of industrial resistance temperature probes, based on a thin-film platinum resistance temperature detector. The experiments were carried out with four jacket thin-film resistance temperature probes, all having identical protection tube geometry, yet differing in the thermal insulation filling materials. Further, a comparison between transient response characteristics in water established experimentally and those based on simulations with electric–thermal analogy, is given. The results of these analyses can be applied to enhance the dynamic response of temperature measurement made by temperature probes in water.     

HTF对r、d、n、δ、△N微分的计算

本文推导了传递函数MTF对结构参数r、d、n的微分计算公式,给出了MTF对偏心差δ和局部光圈△N的微分表达式,这些对于以MTF为性能指标,优化求解公差和光学自动设计,都是很有用处的。     

利用VisualC＋＋编程实现端面磨损试验机的实时监控和试验数据的实时处理

介绍了一个端面磨损试验系统。利用基于VisualC 编制的程序通过计算机和电路系统来控制试验机,实现对试验机的实时监控和试验数据的实时处理。使它成为一个自动化程度高、效率高、精度高的实验系统。     

Automatic, tracking, peak timer

We have designed an inexpensive instrument for automatically measuring time of flight for repetitive signals. It is stable in the presence of noise resembling the real signal. Specific peaks in a multipeak signal can be timed to an accuracy of about 10 ns with the present design. The output is either a digital word or an analog voltage. Computer control is simple and would make it possible to time several signals with the same instrument.     

电感耦合等离子体质谱法测定大米中砷铅铜锌铬镉镍元素含量

建立电感耦合等离子体质谱法（ICP-MS）一次进样同时测定大米中重金属As、Pb、Cu、Zn、Cr、Cd、Ni元素含量的方法。实验表明,本方法的线性范围宽,线性相关系数在0.9994～0.9999范围内;元素检出限低,7种重金属元素检出限范围为1.52～51.3μg/kg;精密度良好,测定7种重金属元素含量的相对标准偏差均〈5%;采用国家标准物质大米（GBW10010）和玉米（GBW10012）测定对照,评价了方法的准确性,各元素的回收率在91.2%～110%范围内。结果表明,该方法简便、快速、灵敏、准确,适用于大米、玉米中7种重金属元素含量的同时测定。     

密闭消解电感耦合等离子体质谱法测定铝土矿中锂、锶、镓、铌、钽、锆和铪

采用电感耦合等离子体质谱,硝酸-氢氟酸增压密闭消解样品,实现了铝土矿中锂、锶、镓、铌、钽、锆和铪的同时测定。实验中探讨了最佳的消解程序,选择适当的同位素,并用铑、铼做内标元素,有效地抑制了分析信号的漂移。各元素的检出限在0.02～1.00μg.g-1,相对标准偏差在0.63%～1.63%,Nb,Ta,Hf的回收率在99.2%～99.6%;该方法经国家标准物质（GBW07177,GBW07182,GBW07180）验证,各元素测试结果与真值很接近。     

ICP-MS法快速测定化妆品中铬、砷、镉、钕、铅

建立化妆品中铬,砷,镉,钕,铅的电感耦合等离子体质谱测定分析方法。样品预处理采用微波消解,以⁷²Ge、¹¹⁵In、²⁰⁹Bi为内标作定量分析,对3种不同基质的化妆品进行测定,对照分析了参考标准物质。各元素平均回收率为88.8%～108%,相关系数均大于0.999,相对标准偏差（RSD）为1.1%～8.8%。     

Yeast mitochondrial dynamics: fusion, division, segregation, and shape

Mitochondria are essential organelles found in virtually all eukaryotic cells that play key roles in a variety of cellular processes. Mitochondria show a striking heterogeneity in their number, location, and shape in many different cell types. Although the dynamic nature of mitochondria has been known for decades, the molecules and mechanisms that mediate these processes are largely unknown. Recently, several laboratories have isolated and analyzed mutants in the yeast Saccharomyces cerevisiae defective in mitochondrial fusion and division, in the segregation of mitochondria to daughter cells, and in the establishment and maintenance of mitochondrial shape. These studies have identified several proteins that appear to mediate different aspects of mitochondrial morphogenesis. Although it is clear that many additional components have yet to be identified, some of the newly discovered proteins raise intriguing possibilities for how the processes of mitochondrial division, fusion, and segregation occur. Below we summarize our current understanding of the molecules known to be required for yeast mitochondrial dynamics.     

Johns Hopkins University, Baltimore, Maryland

The STEM can be used in one of three modes: 1) to image individual atoms; 2) to measure mass or molecular weight; 3) to collect electron energy loss spectra or x-ray fluorescence data. Heavy atom imaging is used to identify chemical groups in a molecule or macromolecules in an assembly. Specific labels have been developed for bases in nucleic acids. These permit localization of bound proteins on single strand nucleic acids. Pt(gly-L-met)Cl is a specific label for methionine residues of proteins as shown with the SLS aggregate of collagen. Lysine can be labeled as well if first methyl (methyl-thio-acetimidate) is coupled. This labeling procedure permits the localization of individual histones within a nucleosome. Mass determination can be used to answer crucial questions about biological assemblies. This is demonstrated by examples from muscle structure.     

EFFECTS OF TESTING,ANALYSIS, DAMAGE,AND ENVIRONMENT ON MODAL PARAMETERS

Experimental and analytical modal analysis techniques have been widely used in civil engineering for a number of years, mostly in seismic applications. Since the beginning of this decade, these techniques have received considerable attention in non-seismic applications such as structural damage detection, analytical model calibration and remote-monitoring systems. In these applications, most studies have concentrated on correlating modal parameters to changes in structural condition. However, for reliable performance of modal techniques in field situations, it is essential to understand and establish the variability of modal parameters due to test procedures and in-service environments of structures. New York has been researching this subject extensively for the past few years, and has tested several structures including (1) a 1/6-scale model highway bridge, (2) an abandoned fracture-critical highway bridge and (3) an in-service highway bridge. Both the abandoned highway bridge and model bridge were tested under intact and simulated-damage conditions. This paper briefly describes these studies. Results indicate that modal frequencies in conjunction with mode shapes may be used to identify the existence of bridge damage or deterioration of interest, but it is difficult to isolate damage locations using these modal parameters. Operating conditions affect the modal properties and are critical in establishing a baseline for structural monitoring.     

两种做法，两种观念，两种结果——评“百篇优秀博士论文评选”

中国和美国的高等教育实在是太不一样了。就博士培养中的“百篇优秀博士论文的评选”来看，这种差异决非表面的，形式上的，方法上的。中国是“经营者”利益至上而虚晃一枪的“选优”，美国是“消费者”利益至上却实实在在的“去劣”，很不相同。一个是行政权力主导，一个是教授学术主导，主导者十分不同。不是中国人不聪明，不是中国教授不智慧，不是中国大学不争气，一切都在于落后的体制，一切的根本障碍在体制。解答“钱学森之问”的根本就是大学要“去行政化”，要解决“大学究竟由谁来办”的问题。     

ICP-AES法测定铁镍合金中的铬、钴、锰、钼

ICP-AES法测定铁镍合金中的铬、钴、锰、钼,同时对仪器各项参数进行优化,采用基体匹配法克服基体干扰,通过选择合适的分析线和调背景消除共存元素干扰,方法应用于实际样品分析,精密度好,检出限低,回收率高,测定结果与AAS法的测定值相符。     

Mott factors of P,V, Fe,Ga, As,Pd, In,Ta, and W for 500–3000 eV electrons

Mott scattering factors are needed for the quantitative interpretation of elastic scattering phenomena in electron spectroscopy and microscopy. The inelastic mean free path of electrons has been deduced from the elastic peak intensity. The theoretical approach is based on the effective elastic cross section derived from the differential elastic cross sections. In the present work they are calculated using the partial wave expansion method, supplying as well the Mott scattering factors. Tabulated data are presented for a number of elements and 500–3000 eV electrons in steps of 2° or 5° of the scattering angle θ. The effective and total elastic scattering cross sections are also presented.     

CaF2, MgF2, SiO2, Al2O3, SiC, LiF, BaF2, and ZrO2 optical single crystals used in studies in the VUV spectral region

Spectral characteristics of single crystals—fluorite, magnesium fluoride, quartz, sapphire, silicon carbide, lithium fluoride, barium fluoride, and fianite—used as materials for optical windows in studies in the VUV spectral region are presented. Spectral and photometric studies of single crystals in the spectral range 30–700 nm were performed on a BM-70 vacuum spectrophotometer. This instrument is equipped with a vacuum chamber for measuring the light transmission and reflection at radiation angles of incidence between 10° and 70°; this allows both characteristics to be measured sequentially in time without breaking vacuum. Replaceable radiation sources (with and without a window) were used to perform studies in the spectral range 30–700 nm, including measurements in flows of atmospheric and inert gases (Ne, He, Ar, N, and H).