大比转速双吸泵吸水室CFD数值模拟

近年来,计算流体力学(CFD)技术已经成功地运用于数值模拟离心泵内部湍流流动。文章以型号为300S19双吸式离心泵为研究对象,使用FLUENT软件分别计算了多种不同工况条件下的双吸泵内部流场,并在原半螺旋吸水室的基础上进行改进,分别测试了在直锥型,鹅颈弯管型吸水室的各工况的内部流场,从而得到大比转速双吸泵理想的吸水室形状。     

Visual Basic 6.0中正则表达式的应用

介绍了正则表达式及其构造策略,并通过验证字符串中URL地址的合法性以及使用正则表达式查找并替换文本和代码的应用实例,说明正则表达式在Visual Basic 6.0中的应用.     

我矿3号井卤水浓度居高不下原因的探讨

通过对引起浓度居高不下的原因、盐层埋藏情况、卤井建槽期的生产情况、管串组合、卤井生产现状等进行综合分析,提出了解决浓度居高不下的措施,在该卤井生产中取得了较好的效益。     

On-line measurements in pig carcass classification: Repeatability and variation caused by the operator and the copy of instrument

For nearly all pigs slaughtered in the EU, the lean meat content is assessed on-line at the slaughter line. The assessment is made indirectly by an instrument performing a number of informative measurements including the thickness of back fat as one of the most important and common measurements. Several types of instruments are used for making the measurements. The quality of the calibration (the prediction ability) has to be approved by the EU Commission. However, the maintenance of instruments, training of operators, working conditions and other factors influencing the routine are quite as important for the accuracy as the calibration. As a part of an EU funded project, partners representing thirteen European countries have investigated the instruments used in their countries focusing on the precision of indirect measurements. The preconditions have differed considerably between the countries resulting in a wide range of estimates of the repeatability and the reproducibility (precision) of fat and muscle thickness. Totally, there have been three different types of manual instruments - invasive probe instruments from three manufacturers, non-invasive ultrasound and callipers. Furthermore, the precision of two automatic instruments with respect to lean meat content has partly been estimated. Even though neither the aim nor the design of the experiments was set for a direct comparison between different instruments, none of them seemed to deviate notably from the others with respect to the precision of fat thickness. In this study, the only investigated influencing factors were the variations in operators and copies of instruments. Generally, the variations between operators were more important than the variation between copies of the same type of instrument.     

A novel approach for simulation of curling behavior of knitted fabric based on mass spring model

Edge curling is a unique property of knitted fabrics which affects on fashion such as using upper and side curling in cloth design. The purpose of this research is to present a new method to simulate drape behavior of knitted fabric considering difference between single and double jersey knitted fabrics. To this point, at first the bending and torsion moments that applied on the fabric edges and caused curling in single knitted fabric are determined. Also it demonstrated that these moments will be neutralized in double knitted and as the results, leads to a non-curling structure. Then, using the mass spring model, curling shape in fabric wale and course directions are simulated. To show efficiency of the proposed model, real 3D shape of single knitted fabric is compared with experimental results. Also, using the proposed model, the drape behaviors of single and double jersey knitted fabrics hanging from two fixed corners with different properties are simulated and then extend to simulation of skirt. Results of simulation are compared with 3D shapes of actual drape behavior in fabric samples which are achieved by depth camera. The simulated results show good agreement with 3D shapes of actual fabrics.     

String,Space and Surface in the Photography of Vik Muniz

Abstract

This article examines three series of works by the artist Vik Muniz—Pictures of Thread, Piranesi Prisons and Pictures of Wire. These works employ a string-like material to convey pictorial space. The “string” is utilized in different ways: to create a type of landscape tapestry, as a drawing constructed through “string art” techniques, and to make sculptural drawings. The use of string provides a three-dimensional element to the work, yet this apparent three-dimensionality jars with the presentation of the work as photographs of the original drawings. This article proposes an analysis of the work as reflexive examinations of the photograph. The structure of the article follows the movement from the nomadic quality of the string in Pictures of Thread, through to the taut grid construction of Piranesi Prisons and, finally, to the tensile rigid “string” of Pictures of Wire. The first section considers Muniz's Pictures of Thread and Piranesi Prisons series in relation to pictorial space and the haptic. The second section examines Pictures of Wire as an example of trompe l'oeil and simulacra. The article concludes by considering the flatness of the photograph in relation to a Deleuzian account of surface.     

食品检验检测使用浓缩仪的评价验收

食品检验检测实验室在使用溶剂浓缩仪开展实验、检测等活动之前应对其性能指标进行确认。针对旋转蒸发类和氮吹类溶剂浓缩仪的评价验收可分为两方面内容：其一,溶剂浓缩仪的评价。包括仪器工作条件的审核,仪器外观要求,仪器功能评价,仪器的标志、包装、文件、运输、储存,相关质量保证及售后服务等内容,这部分评价方法可参考国家相关标准进行判定。其二,溶剂浓缩仪的质量验证和验收。可采用乙腈和正己烷作溶剂对上述两类溶剂浓缩仪分别进行平行性性能测试。对已有国家标准及行业标准中相关仪器的试验条件进行统计以确认仪器测试条件,通过测试浓缩时间及浓缩时间相应的置信区间,两种溶剂得出的浓缩时间的置信区间分别在0.43～3.38和0.93～5.41之间。该置信区间可作为不同样品浓缩仪平行性合格与否的依据,从而判定溶剂浓缩仪的优劣。完成实验室溶剂浓缩仪的评价验收有助于实验室质量体系的完备,提高实验室日常检测的可靠性。     

活性染料刮涂冷堆染色法在工业用呢上的应用

本文对用于某种仪器的工业用呢进行了国产化研制。该工业用呢与服装面料不同、除了表面要求大红色泽外,织物内部要求仍保持“白芯”,以满足仪器制造工艺的需要,对于这种表面着色的特殊要求,一般染色工艺是达不到的。我们采用活性染料双面刮涂染色,对染料,助剂,工艺条件等进行了筛选和试验,获得了较为满意的效果。     

弦方程的逆谱问题

借助Liouvlle变换,将弦方程转化成势方程.利用研究势方程逆问题的方法研究了弦方程在不同谱信息下的逆谱问题,得到弦方程密度函数与其特征函数的关系,确定了弦方程的密度函数.     

Sawblade design: theory and practical application

It is generally well known that any alteration in sawtooth shape can influence blade performance considerably. While the effect of such general alterations in shape is seldom quantified in practice, the specific quantitative effects of modifications in shape and hardness of the sawtooth apex are virtually unknown. As the sawtooth apex is the major working part of the cutting tool, better understanding of its geometry should lead to significant improvements in sawblade design.     

Mechanical behaviour of carbon and glass filament yarns under high temperatures for composite applications

Fibre composites made with high-performance fibres composed of carbon and glass are used in numerous technical applications due to their physical and chemical properties, which are valued for their high strength capabilities. Also in the construction field, textile fibres are gaining importance as reinforcements for concrete and are being coated to improve their bonding performance. Under thermal loads, these yarns show structural alterations in their mechanical properties. The following paper is concerned with experimental investigations of the strength and elasticity of commonly used textile fibres under high temperatures with the goal of specifying the materials’ parameters relative to thermal conditions.     

A laboratory intercomparison of real-time gaseous ammonia measurement methods

Six different measurement methods (and seven instruments) for the measurement of gaseous ammonia at low part-per-billion levels were compared simultaneously in a laboratory setting. The instruments were the tunable diode laser (TDL) absorption spectrometer, the wet scrubbing long-path absorption photometer (LOPAP), the wet effusive diffusion denuder (WEDD), the ion mobility spectrometer (IMS), the Nitrolux laser acousto-optical absorption analyzer, and a modified chemiluminescence analyzer. With the exception of the modified chemiluminescence analyzer, the instruments performed well and, understable calibration conditions, generally agreed to within about 25% of the expected calibration value. Instrument time response is shown to be sensitive to measurement history as well as the sample handling materials and is shortest for the TDL. The IMS and Nitrolux are commercial instruments used without modification from the manufacturer. These two instruments have significantly slower time response than the TDL (especially in the case of the Nitrolux) and exhibited measurement biases of approximately +25% (IMS) and -25% (Nitrolux). The LOPAP and WEDD instruments, both research instruments using wet chemical methods, performed well in the calibration tests in terms of the absolute accuracy of measured concentrations, but the WEDD instrument suffered from significantly slower time response than the LOPAP.     

The Fabric of Moroccan Life

Abstract

The transformative properties of string are considered via an analysis of string figures, also known as cat's cradles, which are loops of string manipulated to form three-dimensional patterns in sequence. This article looks at the string figures which form part of the collection made by A.C. Haddon in 1888, of everyday objects used by Torres Strait islanders. He promoted the documentation of string figures as a means of ethnographic enquiry, notably via the 1902 publication A method for recording string figures and tricks, co-authored with W.H. Rivers. The article considers how representation of Haddon's string figures and the significance attributed to them have changed. Haddon's string figures are analyzed in their various forms and contexts: as objects acquired by the British Museum in 1889, as published representations of the string figures, and as performance. How meaning is gained during the performance of string figures is understood here as due to the transformative properties of string as a medium.     

白酒生产企业化验室建设

白酒生产企业化验室建设包括硬件建设和软件建设两大部分,其主要内容为：科学合理的化验室设计,必备的现代分析仪器,齐全的化学试剂和高素质的分析化验人员,完整的管理制度。     

气圈形态及张力与倍捻机气圈类型分析

提出用三个特征参数描述气圈形态的方法，并选择出能够最有效反映变化的形态特征参数。利用气圈的形态和张力的关系，分析了倍捻机气圈的三种类型。     

A quick, practical test procedure to evaluate the performance of instruments used for in vitro UV protection measurements

The in vitro determination of the UV protection of sunscreens is usually performed by means of transmission measurements with special photometers. Many different instruments are used. Besides numerous commercially available instruments, which are equipped by the manufacturer for the specific measurement, other modular instruments are used. We present here a quick and practical method to evaluate the performance of these instruments with respect to their measuring ranges and to compare the uniformity and reliability of the results obtained with these instruments.     

Disruption of six unknown open reading frames from Saccharomyces cerevisiae reveals two genes involved in vacuolar morphogenesis and one gene required for sporulation

In this report we describe the construction and basic phenotypic analysis of deletion mutants in six open reading frames (ORFs) of unknown function from the yeast Saccharomyces cerevisiae. Using the dominant kanMX marker and polymerase chain reaction (PCR) methods, deletion cassettes were constructed for five ORFs (YNL099c, YNL100w, YNL101w, YNL106c and YNL242w) located on chromosome XIV and one ORF (YOR109w) located on chromosome XV. The recovery of viable haploid deletant strains among the meiotic products of heterozygous deletants for each ORF demonstrated that none of the analysed ORFs was essential. With the exception of YNL242w, no alterations in growth characteristics or mating and sporulation efficiencies associated with deletion of the ORFs were observed. Homozygous diploid ynl242w delta cells obtained in three different genetic backgrounds were unable to sporulate, indicating that the product of this ORF is required for sporulation. Complementation of the sporulation defect by the cognate gene clone confirmed this observation. YNL106c and YOR109w are very similar and show strong sequence homology with a mammalian phosphatidylinositol-phosphate 5-phosphatase, synaptojanin, known to be involved in synaptic vesicle cycling. Strains bearing single and double deletions of YNL106c and YOR109w were seen to display abnormal vacuolar morphologies of varying degrees. Complementation tests indicated that YNL106c and YOR109w are redundant genes.     

织物导湿排汗性能自动测试方法

针对目前常规织物导湿排汗性能测试仪器自动化程度不高,测试精度低等问题,依据织物干燥与润湿状态下电阻值的显著变化设计了一套高精度、全自动织物导湿排汗测试装置。借助自制仪器对11块Coolmax涤纶针织物的导湿排汗性能进行了测试,并分别将毛细效应法及质量称量法结果与自动测试装置测试结果进行对比。结果表明：织物导湿排汗测试装置测试重复性和再现性好,可完成液滴在织物内部扩散及蒸发情况测试;织物多方向芯吸指标优于纵横2方向芯吸指标,织物干燥时间测试结果较传统质量称量法测试结果准确;液滴在织物不同方向上芯吸速率和干燥时间的最大极差率数值较大,织物各方向芯吸性能和干燥性能差异明显。     

Die Wechselbeziehung von Bauteilverhalten und zeitgeraffter Wettersimulation

Time-lapse weathering of wooden building elements was carried out with the help of a double climate chamber with two sections, one with computer controlled exterior climate, the other with interior climate. This test arrangement enabled reactions of building parts most similar to reactions under natural weather conditions. As related to the building parts construction, time-lapse factors up till 10 were reached (1 year in 36 days). By computerized simulation procedures, which are applied parallel to time-lapsed weathering, building elements, just in their developing state, can be tested for their suitability under certain border conditions. For the technological transfer and for the export of prefabricated houses into regions with deviating climate conditions, the risk of damage can be minimized by this method.     

国产卧式双螺旋辊馒头成形机的分析研究

本文简述了卧式双螺旋辊馒头成形机的主要结构 ,传动原理和成形原理 ,并提出了馒头机需改进和提高的内容