流量计的选用

本本文介绍了流量计的分类及如何从数以百计的流量计中选出最为适合自己的流量仪表。为非流量仪表专业人员提供了一种简便易行的选择步序，并从多个角度介绍了影响流量计选择的要素，给出了流量计使用和维护的一些建议。     

智能流量仪表与批量控制

１流量特性对流量计的要求１．１流量特性决定了选用流量计的动作原理在化学反应生产过程中,为了对生产进行指导、控制,流量仪表的使用是必不可少的。根据生产工艺复杂程度的不同,生产要求的各不相同,使用流量仪表的种类也各不相同。在某助剂生产过程中,我们也使用了...     

GE气体超声流量计仪表系数不确定度的评定

超声流量计在工业生产检定校准中的应用越来越多,适用于管径比较大、不易拆装的气体流量计校准场合,那么对气体超声流量计本身的要求就越来越高。本文就检定超声流量计时对瞬时流量仪表系数的不确定度评定提出了一些方法以及影响的量。     

浅谈电磁流量计在使用中应注意的事项

电磁流量计是测量导电液体的流量仪表,由于操作不当,往往影响其测量精度。本文从管路设计、安装、维护等方面介绍电磁流量计在使用过程中应注意的事项。     

2011年流量仪表市场同比保持17．8%增长

2011年中国流量仪表市场表现良好,整体规模达到55．6亿元,市政、化工、石化等主要应用领域的良好增长驱动同比实现17．8％快速增长。质量流量计和电磁流量计依旧是整体流量仪表市场的主要应用种类,整体流量仪表市场格局表现为集中度不高且逐年下降走势。     

复杂工艺管道巧用弯管流量计实现流量测量

介绍了在走向复杂的工艺管道或各种原因工艺管道直管段不符合流量仪表安装要求的情况下,合理利用弯管流量计测量原理,实现工艺介质流量测量的成功案例,是对弯管流量计在工业生产过程中合理使用的一种探索。     

正压法气体流量标定系统的设计与实现

随着非标准流量仪表种类和数量的日益增加,为了保证仪表的测量精度。非标流量仪表的标定要求显得日益迫切。系统采用了国际标准文丘利作为标准表。应用标准流量计“比较法”原理,配合计算机程序控制,建立气体流量标定系统。进行流量计的检定和测试。依据有关的国家检定规程。该装置可对多孔孔板、V锥、楔形、巴类等差压式仪表以及涡轮、涡街、旋进旋涡等流量计进行检定、工业现场流量模拟实验以及风洞实验。通过运行实践证明,该系统测量精度高,稳定性好,标定流量范围宽。     

在线流量比对试验的研究

根据超声波流量计非接触式测量特点,运用已证明的切实可行的操作程序,对在线流量仪表比对,从而达到对在线流量仪表测量准确可靠.     

日本流量仪表的发展动向

详细介绍了日本流量仪表包括差压流量计、电磁流量计、容积式流量计、面积式流量汁、旋涡流量计、超声波流量计及质量流量计的发展动向。     

德尔塔巴流量计在流量测量中的应用

介绍了一种用于流量测量的德尔塔巴流量计,简述了德尔塔巴的测量原理以及基本结构,详细的介绍了德尔塔巴流量计的特点并与孔板、转子流量计、涡街流量计等常见的流量仪表进行了对比,通过实例阐述了德尔塔巴在实际工程应用中的价值。     

高压旋喷灌浆自动记录系统

为了满足动态检测高压旋喷灌浆施工过程的需要,运用传感器技术、电子技术与微机技术成功研制了高压旋喷灌浆自动记录系统,介绍了其硬、软件结构的设计,及其在长沙某工程灌浆试验中的成功应用.实验结果表明:该仪器具有稳定性好、精度和灵敏度高、响应速度快等特点,在高温、潮湿、高灰尘的恶劣施工现场能正常工作.     

基于冗余技术EPB盾构同步注浆控制系统设计

详细阐述了冗余控制技术原理及特点,以提高盾构自动控制系统可靠性为目的,基于硬件冗余控制技术开展土压平衡(EPB)盾构同步注浆控制系统软件的控制回路流程分析,关键控制算法设计,并对同步注浆系统的控制条件的关联性和控制回路流程进行分析研究。通过室内实验对上述设计进行验证、总结。对硬件冗余控制技术在盾构自动控制系统中应用前景进行了展望。     

新型矿用注浆封孔机的设计与研究

为了确保煤矿安全生产,需要在煤层的开采过程中测定煤层瓦斯压力以及抽放瓦斯。钻孔的封堵质量好坏直接影响着瓦斯压力测定和瓦斯抽采的效果。新型矿用注浆封孔机采用手一电双动力方式对瓦斯抽放孔、测定孔进行封堵。通过设计要求的参数利用最jJ~--乘法计算出曲面零件的拟合曲线,拟合曲线的零件能够有效降低设备工作时柔性冲击和整体振动。试验表明新型注浆封孔机注浆压力高、封堵效果好且操作简单、安全方便,可广泛应用于矿井钻孔的封堵及建筑结构的裂缝填补等方面。     

带有调浆装置的双液注浆泵的设计研究

双液注浆泵已广泛应用,但注浆的两种浆液在配比上不能实现很好的控制;通过对工业液压系统及液压泵的研究,提出了一种新的双液注浆泵调浆装置。带有该装置的双液注浆泵能够方便地控制两种浆液的比例,在一定范围内实现了无级调节,很好满足两种浆液配比上的要求,拓展了注浆泵的应用空间。     

直齿轮渗碳层厚度分布与组织改善技术途径

针对传统的“先成形，后渗碳”工艺在硬齿面齿轮渗碳层厚度分布和组织形态方面存的问题，提出齿轮“渗碳一温挤”成形新工艺。实验结果表明，通过调整模具结构(模具圆角半径等)、合理选择成形工艺参数(成形温度等)，可使齿轮渗碳层厚度分布合理、组织改善(晶粒细化)。     

A study on the fault diagnosis of roller-shape using frequency analysis of tension signals and artificial neural networks based approach in a web transport system

Rollers in the continuous process systems are ones of key components that determine the quality of web products. The condition of rollers (e.g. eccentricity, runout) should be consistently monitored in order to maintain the process conditions (e.g. tension, edge position) within a required specification. In this paper, a new diagnosis algorithm is suggested to detect the defective rollers based on the frequency analysis of web tension signals. The kernel of this technique is to use the characteristic features (RMS, Peak value, Power spectral density) of tension signals which allow the identification of the faulty rollers and the diagnosis of the degree of fault in the rollers. The characteristic features could be used to train an artificial neural network which could classify roller conditions into three groups (normal, warning, and faulty conditions). The simulation and experimental results showed that the suggested diagnosis algorithm can be successfully used to identify the defective rollers as well as to diagnose the degree of the defect of those rollers.     

An investigation of the hole machining processes on woven carbon-fiber reinforced polymers (CFRPs) using abrasive waterjets

An investigation of the hole cutting and drilling processes on woven carbon-fiber reinforced polymer sheets using abrasive waterjet (AWJ) is presented. The drilling process uses a stationary AWJ to impinge a target material to make a hole, while the cutting process requires an AWJ to penetrate the workpiece before moving in a circular path to cut a hole. It is found that the holes machined by both the processes exhibit similar geometrical features, where the diameter at the top is greater than at the bottom. It is further found that the holes from the drilling process have a better roundness than those from cutting process primarily due to the jet instability during cutting movement. Plausible trends of the hole characteristics (e.g., diameter and wall inclination) and defects (e.g., delamination) with respect to the process parameters are discussed. It is shown that water pressure is the major parameter affecting hole defects. The hole drilling process yields more severe defects than the cutting process because of the initial impact of the jet. Predictive models for machined hole diameter in both processes are developed. The model predictions are in good agreement with the experimental data under the corresponding conditions.     

高压喷桩在市政工程基坑施工中的应用分析

高压喷桩技术需要建立在注浆法的基础上,由高压喷射技术发展而来,该技术是一种地基加固技术。高压喷桩技术需要进行水泥喷浆,而采取的方式是高压旋转的喷嘴方式进行,在土层中喷注水泥,将水泥与土体混合,从而形成连续搭接的水泥加固技术。文章就高压喷桩在市政工程基坑施工中的应用进行了分析。     

Bacteria-hemocyte interactions and phagocytosis in marine bivalves

Marine bivalves (such as mussels, oysters, and clams) are widespread mollusks in coastal waters at different latitudes; due to their filter-feeding habits, they accumulate large numbers of bacteria from the harvesting waters and may act as passive carriers of human pathogens. To cope with this challenge, bivalves possess both humoral and cellular defense mechanisms with remarkably effective capabilities. The circulating cells, or hemocytes, are primarily responsible for defense against parasites and pathogens; microbial killing results from the combined action of the phagocytic process with humoral defense factors such as agglutinins (e.g., lectins), lysosomal enzymes (e.g., acid phosphatase, lysozyme), toxic oxygen intermediates, and various antimicrobial peptides. In this work, current knowledge of the mechanisms underlying the interactions between bacteria and the hemolymph components of marine bivalves is summarized. Bacterial susceptibility to hemolymph killing in different bivalve species may be a consequence of the different ability of bacterial products to attract phagocytes, the presence or absence of specific opsonizing molecules, the hemocyte capability to bind and engulf different bacteria, and the different bacterial sensitivity to intracellular killing. The role of soluble (e.g., agglutinins and opsonins) and surface-bound factors in bacterial phagocytosis by hemocytes of the most common marine bivalve species is described and the possibility that environmental temperatures and other seasonal factors may influence this process is considered. Moreover, the potential strategies used by bacteria to evade phagocytic killing by hemocytes are discussed. From the available data it is clear that several questions need further investigation; the elucidation of the factors influencing phagocytosis in bivalves and the fundamental strategies used by bacteria to escape hemolymph killing are important not only to understand bivalve immune defenses but also to explain the persistence of pathogenic bacteria in bivalve tissues and to predict the consequent impact on human health.     

大众化教育背景下《机械原理》教学综合改革的实践

在大众化教育背景下,围绕《机械原理》的教学,指出其主线是产品设计,并且提出相应的教学内容体系重组问题和以专业机械为教学过程载体等教学综合改革措施。教学实践效果较好,学生的工程实践、应用及创新能力得到培养。