西门子S7-200系列PLC通讯功能与应用

ＳＩＭＡＴＩＣＳ７－２００系列ＰＬＣ（ＰｒｏｇｒａｍｍａｂｌｅＬｏｇｉｃＣｏｎｔｒｏｌｅｒ）是西门子家族中最小型的ＰＬＣ,共有５种基本型号（共１８种）的ＣＰＵ,其基本型号分别为ＣＰＵ２１０、ＣＰＵ２１２、ＣＰＵ２１４、ＣＰＵ２１５、ＣＰＵ２１６,控制...     

西门子 S7-200 系列 PLC 的硬件特点

Ｓ７－２００系列可编程控制器（简称ＰＬＣ）是西门子公司１９９５年底推出的新一代微型ＰＬＣ，由于其性能价格比极高，目前已经在各个领域得到广泛的应用。根据其性能Ｓ７－２００系列可编程控制器可以分５个基本机型：ＣＰＵ２１０、ＣＰＵ２１２、ＣＰＵ２１４、ＣＰ...     

SIEMENS PROFIBUS—PA网络概述（续）

三、ＰＲＯＦＩＢＵＳ－ＰＡ网络之组态３．１软件工具ＰＲＯＦＩＢＵＳ网络之组态主要决定于所使用的主站。笼统地讲,人们必须告知主站,下联网络在它整体中的结构是怎样的。分网络的组态包括有关的现场仪表和部件。将ＰＲＯＦＩＢＵＳ－ＤＰ／ＰＡ部件和ＨＡＲＴ仪表组态到它们的自动化系统中应遵守统一的规则,无论它们是一个标准的Ｉ／Ｏ模块或者一个ＨＡＲＴ模拟模块;无论是一个ＤＰ－从站,还是一个ＰＡ－从站。对于西门子主站系统有若干方便的软件工具可供使用：（１）ＣＯＭＰＲＯＦＩＢＵＳ（适用于ＳＩＭＡＴＩＣＳ５）ＣＯＭＰ…     

新偶氮试剂5－氟偶氮胂I的合成及在铝（Ⅲ）荧光光度法测定中的应用

本文报道了新试剂５－氟偶氮胂Ｉ（５－ＦＡＳＡ－Ｉ）的合成方法，研究了其荧光光度法测定铝的反应条件。Ａｌ（Ⅲ）与试剂在ｐＨ５．６０ＨＡＣ－ＮａＡｃ缓冲介质中形成１∶１型红色配合物并呈现荧光，其λｅｘ／λｅｍ＝３４８．６／３９１．４ｎｍ，线性范围为０～５μｇ／２５ｍｌ，检测限为３．０ｎｇ／ｍｌ。应用于茶叶样品中铝的分析，结果满意     

SP－90泵微机测试系统

ＳＰ－９０泵微机测试系统杭州水泵总厂（３１００１６）沈文治，王寿根一、系统简介ＳＰ－９０工业泵微机测试系统，如图１示，采用双微机系统。其上位机采用ＩＢＭＰＣ／ＸＴ普及型机，ＣＰＵ为８０８８，该机未经任何变动，是完全独立的，可看作一般微机使用、由于同类...     

PC.DCS系统在燕山石化公司化工二厂聚丙烯装置上的应用（二）

本文介绍了在石油化工装置中，采用以智能控制仪表为控制级，以工业ＰＣ为操作站，采用，通信适配器（智能通信卡）所组成的ＰＣ·ＤＣＳ系统，重点讨论了其通信方式、ＰＣ·ＤＣＳ用传统ＤＣＳ的比较，具体给出了１１５吨／年聚丙烯装置ＰＣ·ＤＣＳ的控制系统。     

PC·DCS系统在燕山石化公司化工二厂聚丙烯装置上的应用(一)

本文介绍了在石油化工装置中，采用以智能控制仪表为控制级，以工业ＰＣ为操作站，采用通信适配器（智能通信卡）所组成的ＰＣ·ＤＣＳ系统，重点讨论了其通信方式、ＰＣ·ＤＣＳ同传流ＤＣＳ的比较，并具体给出了１１５万吨／年聚丙烯装置ＰＣ·ＤＣＳ的控制系统。     

ISO/IEC JTC1 SC28第十一届年会

一． ＩＳＯ／ＩＥＣ ＪＴＣ１ ＳＣ２８的第十一届年会 ＩＳＯ／ＩＥＣ ＪＴＣ１ ＳＣ２８的第十一届年会于２０００年６月５日－１７日在德国柏林举行。中国办公设备标准化代表团一行四人参加了本届年会,并访问了德国标准化研究所（ＤＩＮ）。德国质量与认证研究所（ＲＡＬ）和ＳＷＳ软件支持公司。 本次年会的特点是： １．世界上静电复印技术产品主要生产国和知名企业几乎都派出了代表,瑞士和荷兰今年正式成为 ＩＳＯ／ ＩＥＣ ＪＴＣ１ ＳＣ２８的 Ｐ成员。 ２．标准研究和立项的范围明显扩大,标准关注的重点不仅局限于一些基础标准…     

ESQUIRE—LC离子井LC／MS^n

ＥＳＱＵＩＲＥ－ＬＣ离子阱ＬＣ／ＭＳ＾ｎ是将惠普（ＨＰ）与布鲁克（ｂｒｕｋｅｒ）的尖端技术相结合的高效液相色谱／质谱（ＬＣ／ＭＳ＾ｎ）系统。惠普公司成功的１１００系列ＨＰＬＣ和先进的电喷雾电离／大气压化学电离（ＥＳＩ／ＡＰＣＩ）离子源与布鲁克公司最新的多极离子阱ＭＳ和ＭＳ＾ｎ分析器完美结合在一起。ＥＳＱＵＩＲＥ－ＬＣ是一种先进的自动化程度最高的液质联用仪。本文是对该仪器的性能特点、技术指标及应用的     

WEAR TRANSITIONS OF C/Cu COMPOSITE MATERIALS

ＷＥＡＲＴＲＡＮＳＩＴＩＯＮＳＯＦＣ／ＣｕＣＯＭＰＯＳＩＴＥＭＡＴＥＲＩＡＬＳ￥ＢｕＹａｎ；ＸｉａｎｇＺｈｏｎｇｘｉａ（ＴｉａｎｊｉｎＵｎｉｖｅｒｓｉｔｙ）Ａｂｓｔｒａｃｔ：ＡｎｕｎｌｕｂｒｉｃａｔｅｄｓｌｉｄｉｎｇｆｒｉｃｔｉｏｎｔｅｓｔｏｎＣ／Ｃ...     

Experimental investigation on the essential work of mixed-mode fracture of PC/ABS alloy

The mixed-mode fracture of polycarbonate (PC)/acrylonitrile-butadiene-styrene (ABS) alloy is experimentally investigated in this work. The essential work of fracture method is employed to measure the mixed-mode fracture toughness of PC/ABS alloy. Results show that the essential fracture work w _e increases significantly with the decrease in loading angles. Crack initiation angles are measured on the fractured specimens. The deviation of crack growth direction from the initial crack plane also increases with the decrease in loading angles, which corresponds to the increase of shear components. Microfracture processes of PC/ABS alloy with different loading angles are examined in situ by a scanning electron microscope. Crazing structures are clearly seen around the crack tip. The appearance, growth, and coalescence of crazes can be observed in the microfracture processes, and the macrocrack propagation direction is finally determined by the coalesced direction of crazes.     

新型密封材料PTFE／TLCP合金耐磨机理研究

本文将热致型液晶与聚四氟乙烯（ＰＴＦＥ）混合,用模压烧结的方法制备出新型的原位复合材料,实验发现这种改性后的塑料合金的耐磨性比纯ＰＴＦＥ有了很大的提高,是一种有应用前景的密封材料。     

玻璃纤维/PC树脂/LY12铝合金叠层复合材料界面处理及其性能

采用热压固化成型工艺，成功制备了玻璃纤维／PC树脂／铝合金叠层复合材料，并对该材料的界面结合状况与性能进行了分析。结果表明：通过对铝合金表面进行喷丸和酸腐蚀综合处理及对玻璃纤维进行0．5％硅烷偶联剂水溶液涂层处理，叠层复合材料各界面的结合状况良好；抗拉强度达到210．2MPa，抗弯强度达到325MPa，冲击韧度大于173．5kJ／m^2，其阻尼性能尤其突出，自由衰减率达到0．332，可与粘弹性阻尼材料媲美。     

碳纳米管/聚乳酸复合材料的制备与性能

用熔融共混的方法制备了碳纳米管(CNTs)/聚乳酸(PLA)复合材料,观察了其球晶形貌和断面形貌,并研究了不同配比的CNTs/PLA复合材料的结晶性能和水解性能。结果表明:CNTs可以作为异相成核剂提高PLA的结晶速率和结晶度,CNTs质量分数为1%时,复合材料的结晶度达到44.9%,CNTs能够在基体中均匀分散;CNTs质量分数小于1%时,断面呈中间层破形貌;随CNTs含量增多,复合材料的球晶直径变大;CNTs能降低PLA的水解速率。     

聚砜/半芳族热致液晶聚合物原位复合材料的形态及性能

向聚砜 (PSF)中加入 5 %可原位成纤的半芳族热致液晶聚合物 (TL CP1) ,原位复合材料的表观粘度同PSF相比有明显降低 ,聚砜的加工性得到明显改进 ,同时复合材料的拉伸强度、弯曲强度、拉伸模量、弯曲模量均有所提高。形态研究表明 :在 TL CP含量为 5 %～30 %范围内 TL CP1均可在基体中分散并形成具有一定长径比的微纤。当 TL CP1用量高于 10 %时 ,原位复合体系呈现明显的皮 -芯形态 ,抗拉及抗弯曲性能发生劣化 ,但模量显著增加     

Potential of a sensitive uric acid biosensor fabricated using hydroxyapatite nanowire/reduced graphene oxide/gold nanoparticle

In this study, a ternary nanocomposite consisting of gold nanoparticles (AuNPs), hydroxyapatite (HAP) nanowires, and reduced graphene oxide (rGO) is synthesized by a simple one‐step hydrothermal method, which is used to modify glassy carbon electrode (GCE) for detecting uric acid. The nanocomposite is characterized through various methods such as scanning electron microscopy, transmission electron microscopy, and X‐ray diffraction. Electrochemical measurements of the modified GCE are performed in a conventional three‐electrode system. Experimental results show that the obtained HAP nanowire and rGO are mixed homogeneously, and the AuNPs are deposited into this matrix. The GCE modified by the nanocomposites have superior electrocatalytic activities for uric acid. The peak current intensities of UAO (uricase)/HAP‐rGO/AuNPs sensing system linearly increase as the uric acid concentration increases substantially in a range of 1.95 × 10^?5 to 6.0 × 10^?3 M (R² = .9943), with a detection limit of 3.9 × 10^?6 M (S/N = 3) and analytical sensitivity of 13.86 mA/M. The biosensor performs well in determining uric acid concentration in human urine samples.     

A Study on the Sliding Wear of Hybrid PTFE/Kevlar Fabric/Phenolic Composites Filled with Nanoparticles of TiO2 and SiO2

TiO₂ and SiO₂ nanoparticles were introduced into hybrid polytetrafluoroethylene (PTFE)/Kevlar fabric/phenolic composites. The results showed the incorporation of TiO₂ nanoparticles can reduce the wear rate of the fabric/phenolic composite at elevated temperatures, although the wear of hybrid PTFE/Kevlar fabric/phenolic composite did not change much when TiO₂ or SiO₂ nanoparticles were used as filler. The wear behavior was explained in terms of morphology of transfer films and worn surfaces. There was a good correlation between the morphology of transfer film and wear results.     

Quantification of metallic nanoparticle morphology on TiO2 using HAADF-STEM tomography

Electron tomography is applied to photocatalytic gold/titanium oxide and gold/silver/titanium oxide samples. In order to obtain a tilt series for the electron tomography measurement, high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) is used under cryogenic conditions. Dedicated programs have been developed for measuring volume, surface area, thickness distribution and nearest-neighbour distance of metallic nanoparticles on samples. Using these quantification programs, the 3D morphology of gold and silver nanoparticles is accurately characterized. We paid particular attention to the quantitative measurement of surface area. The measurement error of the method and appropriate magnification are defined using spherical nanoparticle models. We measured the 3D morphology of gold nanoparticles supported on titanium oxide (total volume=6.5×10⁵ [nm³], surface area=1.4×10⁵ [nm²], and average nearest-neighbour distance=40 [nm]).     

A 2 MV Van de Graaff accelerator as a tool for planetary and impact physics research

Investigating the dynamical and physical properties of cosmic dust can reveal a great deal of information about both the dust and its many sources. Over recent years, several spacecraft (e.g., Cassini, Stardust, Galileo, and Ulysses) have successfully characterised interstellar, interplanetary, and circumplanetary dust using a variety of techniques, including in situ analyses and sample return. Charge, mass, and velocity measurements of the dust are performed either directly (induced charge signals) or indirectly (mass and velocity from impact ionisation signals or crater morphology) and constrain the dynamical parameters of the dust grains. Dust compositional information may be obtained via either time-of-flight mass spectrometry of the impact plasma or direct sample return. The accurate and reliable interpretation of collected spacecraft data requires a comprehensive programme of terrestrial instrument calibration. This process involves accelerating suitable solar system analogue dust particles to hypervelocity speeds in the laboratory, an activity performed at the Max Planck Institut fu?r Kernphysik in Heidelberg, Germany. Here, a 2 MV Van de Graaff accelerator electrostatically accelerates charged micron and submicron-sized dust particles to speeds up to 80 km s(-1). Recent advances in dust production and processing have allowed solar system analogue dust particles (silicates and other minerals) to be coated with a thin conductive shell, enabling them to be charged and accelerated. Refinements and upgrades to the beam line instrumentation and electronics now allow for the reliable selection of particles at velocities of 1-80 km s(-1) and with diameters of between 0.05 μm and 5 μm. This ability to select particles for subsequent impact studies based on their charges, masses, or velocities is provided by a particle selection unit (PSU). The PSU contains a field programmable gate array, capable of monitoring in real time the particles' speeds and charges, and is controlled remotely by a custom, platform independent, software package. The new control instrumentation and electronics, together with the wide range of accelerable particle types, allow the controlled investigation of hypervelocity impact phenomena across a hitherto unobtainable range of impact parameters.