活性炭混捏成型系统设计

针对活性炭的混捏成型工段设计了一种基于西门子S7-200型PLC的自动控制系统,采用称重传感器配合智能称重仪表进行重量数据采集,对各生产原料进行计量配料,还设计了电气控制原理图以及系统软件,采用MCGS组态软件开发上位机监控界面,活性炭成型工序通过变频器控制造粒机来实现。     

2604表在热处理炉渗碳控制中的应用

较详细的介绍了2604表在热处理行业碳势控制中的应用,详细阐明了有关的工作原理和关键技术。系统具有功能多、结构简洁明了、操作方便等优点,在热处理行业中应用十分广泛。     

Determination of ganciclovir as an antiviral drug and its interaction with DNA at Fe3O4/carboxylated multi-walled carbon nanotubes modified glassy carbon electrode

The electrochemical oxidation of an antiviral drug, ganciclovir (GCV) at Fe₃O₄/carboxylated multi-walled carbon nanotubes modified glassy carbon electrode (Fe₃O₄/cMWCNTs/GCE) was studied by voltammetric techniques. The influence of the effective parameters on the electrochemical behavior of GCV was investigated. Under optimized conditions, the proposed sensor was applied for low level GCV determination. The relationship between peak current and the concentration of GCV was linear in the range of 80–53,000 nM with a detection limit of 20 nM through square wave voltammetry (SWV). The interaction of GCV with calf thymus DNA was also explored by voltammetric and spectrofluorometric methods. Based on the obtained data the mode of binding of GCV to DNA was intercalative binding. The decrease in the SWV peak current of GCV in the presence of DNA was used for the determination of DNA. The modified electrode exhibited a good sensitivity, stability and pleasant reproducibility, and it was applied for the determination of GCV in spiked serum and urine, with satisfactory results.     

A kinetic study of interface reactions for an organic molybdenum compound as a lubricant additive

The kinetics of molybdenum-sulphur compounds as anti-wear and extreme pressure additives are studied on a V-block-pin testing machine. The surface films of pins are analysed by Auger electron spectroscopy (AES). The apparent reaction order in the general kinetic equation can be determined from the experimental data. The results show that the composition of the surface film depends on the relative reaction rates of sulphidation and oxidation and can be found from the AES profile, where k is the reaction rate constant. The surface film of a mixture of iron oxide and sulphide possesses better anti-wear properties than the sulphide film alone.     

TEM observations of SiC-SiC composites with a carbon interphase layer annealed in air at high temperatures

SiC–SiC composites with a carbon interphase layer have been annealed in air at high temperature (800–1400°C) in order to determine the oxidation mechanism. Transmission electron microscopy and high-resolution electron microscopy observations have been performed on thin slices of oxidized specimens. Observations show that, with oxidation above 800°C, the carbon interphase can be replaced totally by a thick silica layer, in agreement with previous work. However, in many cases the modified interphase is heterogeneous. The turbostratic carbon structure disappears and the carbon interphase layer is partially replaced by an amorphous silica layer found preferentially at the contact zone between the fibres and the carbon layer. A very thin silica layer can also be observed on the matrix side at the matrix-fibre interfaces. Some decohesion appears in areas where carbon is still present. For short-duration exposures, decohesion occurs between the fibres and the carbon interphase layer.     

Hydrothermal synthesis of a lamellar zinc dimolybdate hydroxide with application as the anode for lithium-ion batteries

Abstract

A lamellar zinc dimolybdate hydroxide Zn₃Mo₂O₈(OH)₂ was prepared for the first time by a facile hydrothermal synthesis. The electrochemical properties of the lamellar Zn₃Mo₂O₈(OH)₂ as an anode material were investigated by cyclic voltammetry (CV), reversible capacity, cycling stability and rate capability for lithium ion batteries (LIB). The lamellar zinc dimolybdate hydroxide exhibits a reversible capacity of 404.6 mAh g^?1 at a current density of 100?mA g^?1 after 200 cycles. The reversible capacity of the lamellar Zn₃Mo₂O₈(OH)₂ remained at 60 mAh g^?1 even at a current density of 3000?mA g^?1. When the current density was returned to 100?mA g^?1, a discharge capacity of 380 mAh g^?1 was maintained after 200 discharge/charge cycles. The excellent electrochemical performance may be due to its unique lamellar structure, which buffers the volume change during the Li⁺ intercalation/de-intercalation and provides the electrode with convenient lithium ions and electron transport pathways. These results suggest the promising potential application of the lamellar zinc dimolybdate hydroxide in lithium-ion batteries.     

基于碳纤维框架天基目标探测二维跟踪转台结构优化

为满足某星载太阳辐照度光谱仪对太阳的跟踪指向技术要求,设计了一种二维转台系统.本文对该转台进行了结构的拓扑优化设计、有限元仿真及试验验证.首先,通过研究和比较现有的转台方案,确定以基本地平式作为转台的结构形式,选择性能优良的M55J碳纤维复合材料作为转台结构的主要材料,配合TC4镶嵌件来连接部件.根据拓扑优化结果和工程...     

An assessment of beeswax as a thickener for environmentally friendly lubricating grease production

Environmentally friendly lubricants are preferred in many applications where groundwater or soil pollution is possible. The main purpose of the current study was to evaluate the possibility of beeswax use as a thickener for lubricating greases. European beeswax was used as a thickening material for the preparation of lubricating greases. Rapeseed oil and two mineral oils were used as base oils. The consistency, dropping point temperature, and tribological properties of the prepared lubricating greases were investigated and compared with conventional soap‐thickened greases. The prepared greases exhibited good tribological properties, especially the rapeseed‐oil‐based grease. However, tribological properties of conventional lubricating grease were superior to prepared ones. The weakness of the prepared lubricating greases is their narrow working temperature range. However, the beeswax together with rapeseed oil has great potential in the production of environmentally friendly, completely renewable lubricating greases. Copyright © 2014 John Wiley & Sons, Ltd.     

面向生产过程质量控制的汽车空调热交换器散热性能检测装置研究及应用

为了保证汽车空调热交换器生产过程中的产品质量,针对汽车空调热交换器生产过程中质量检测方面存在着的问题,以汽车空调热交换器质量指标-散热性能为研究对象,提出了面向生产过程质量控制的汽车空调热交换器散热性能检测装置的设计原理,完成了热交换器散热性能检测装置的硬件和软件的设计与实现;最后对该检测装置进行了实验验证。实验及研究结果表明,所设计完成的检测装置能够用于判定热交换器生产过程是否发生异常情况,从而可以为汽车空调热交换器生产过程质量保证系统的构建奠定一定的基础。     

Development of amorphous carbon coating with luminescent silica/CdSe/ZnS quantum dots underlayer for wear monitoring

Amorphous carbon (a-C) coating with luminescent wear-sensing underlayer is developed for achieving the tribological coating with wear monitoring capability. Wear monitoring of a-C coating by luminescent spectroscopy to determine the remaining thickness of the coating after the wear test is also demonstrated. The coating structure consists of a-C films deposited by R.F. magnetron sputtering method onto the luminescent layer, which is made from silica coating containing CdSe/ZnS quantum dots (Silica/QD). A thin Si-intermediate layer is added between a-C and silica/QD layer for adhesion improvement. The physical as well as tribological properties of the coatings are analysed. Furthermore, wear monitoring of a-C films is also demonstrated to determine the remaining coating thickness after the tribological test. The demonstration is carried out by firstly formulating a relation between luminescent intensity detected from the coating and coating thickness. Then the luminescent intensity is measured again from the wear track. The remaining thickness is finally determined by using the relationship between luminescent intensity and coating thickness. The fabricated coating exhibits a smooth surface with the average surface roughness of 1.35 nm and a friction coefficient of 0.1. The demonstration of wear monitoring shows that the remaining thickness of the coating after the tribological test determined by luminescent spectroscopy is compared well with the thickness measured by profilometry. This suggests that wear monitoring of a-C films by luminescent spectroscopy technique is feasible.     

Triboreactions of graphite with moisture—a new model of triboreactor for integrating friction and wear

In order to account for the influence of environment on the frictional properties of graphite, a new model of tribocontact considering the confined volume under the pin as a triboreactor is proposed. The heart of the reactor is the mechanical production of debris displaying fresh prismatic surfaces. Both the rate of formation and the rate of deactivation of these latter are influenced by the environment and are mutually influencing each the other. The model combines three distinct mechanisms, seldom considered before: (a) the one step embrittlement of graphite governed by the amount of moisture within the contact; (b) the kinetics of water adsorption outside the contact, considered to obey the Elovich equation; (c) the triboreactions between the water and the active surfaces associated with the prismatic surfaces of the graphite debris. The validity of the model is supported by various experimental results.     

物流运行状态远程监控系统的实现

介绍了PROGEA公司开发的工控组态软件Movicon与三菱PLC组成的监控系统,阐述了该系统的功能、组态过程、三菱PLCI／O驱动程序的实现等。根据某厂显像管流水线的生产要求,在Movicon平台上设计完成了对流水线停机累计时间、产量统计和故障报警等的动态监控。     

High‐temperature laser‐scanning confocal microscopy as a tool to study the interface instability during unsteady‐state solidification of low‐carbon steel

Solidification microstructure is a defining link between production techniques and the mechanical properties of metals and in particular steel. Due to the difficulty of conducting solidification studies at high temperature, knowledge of the development of solidification microstructure in steel is scarce. In this study, a laser‐scanning confocal microscopy (LSCM) has been used to observe in situ and in real‐time the planar to cellular to dendritic transition of the progressing solid/liquid interface in low carbon steel. Because the in situ observations in the laser‐scanning confocal microscopy are restricted to the surface, the effect of sample thickness on surface observations was determined. Moreover, the effect of cooling rate and alloy composition on the planar to cellular interface transition was investigated. In the low‐alloyed, low‐carbon steel studied, the cooling rate does not seem to have an effect on the spacing of the cellular microstructure. However, in the presence of copper and manganese, the cell spacing decreased at higher cooling rates. Higher concentrations of copper in steel resulted on an increased cell spacing at the same cooling rates.     

Implication of scanning electron microscopy as a tool for identification of novel,nonedible oil seeds for biodiesel production

Biodiesel is a promising, bio-based, renewable, nontoxic, environment friendly, and alternative fuel for petroleum derived fuels which helps to reduce dependency on conventional fossil fuels. In this study, six novel, nonedible seed oil producing feedstock were explored for their potential for sustainable production of biodiesel. It is very important to correctly identify oil yielding plant species. Scanning electron microscopy (SEM) was used as reliable tool for authentic identification of oil yielding seeds. Macromorphological characters of seeds were studied with light microscopy (LM). Outcomes of LM of seeds exposed distinctive variation in seed size from 16.3 to 3.2 mm in length and 12.4 to 0.9 mm in width, shape varied from oval to triangular, and color from black to light brown. Oil content of nonedible seed ranged from 25 to 30% (w/w). Free fatty acid content of seed oil varied from 0.32 to 2.5 mg KOH/g. Moreover, ultra structural study of seeds via SEM showed variation in surface sculpturing, cell arrangement, cell shape, periclinal wall shape, margins, protuberances, and anticlinal wall shape. Surface sculpturing varied from rugged, reticulate, varrucose, papillate, and striate. Periclinal wall arrangements confirmed variation from rough, wavy, raised, depressed, smooth, and elevated whereas, anticlinal walls pattern showed variation from profuse undulating, smooth, raised, grooved, deep, curved, and depressed. It was concluded that SEM could be a latent and advanced technique in unveiling hidden micromorphological characters of nonedible oil yielding seeds which delivers valuable information to researchers and indigenous people for precise and authentic identification and recognition.     

Coefficient of friction for aluminum in contact with a carbon fiber epoxy composite

In bolted joints, a large part of the load is transferred by friction. The objective of this investigation is to measure the coefficient of friction for carbon fiber epoxy matrix composite, HTA-6376, in contact with aluminum, 3637-77, in reciprocal sliding. During testing, the coefficient of friction increased initially with number of cycles and after reaching a maximum, slowly decreased. The initial coefficient of friction is approximately 0.23 and the peak coefficient of friction after wear in is approximately 0.68. The coefficient of friction is independent of normal load. During wear, cracks are formed at the fiber–matrix interface, which causes the matrix layer on the original composite surface to break off in pieces. It also causes single fibers or groups of fibers to be broken off and removed from the surface. Pieces of carbon fiber caused depressions in the aluminum surface. The wear debris is reattached to the composite surface but not to the aluminum surface.     

Adsorption effect of a cationic surfactant at carbon paste electrode as a sensitive sensor for study and detection of folic acid

The present study is the first report on the effect of cetyltrimethylammonium bromide (CTAB) on the electrochemical behavior of folic acid (FA) at the surface of carbon paste electrode (CPE) in real samples. The studies were performed by cyclic voltammetry (CV), chronocoulometry and differential pulse voltammetry (DPV). CTAB, with a hydrophobic C–H chain, could absorb at the CPE surface by hydrophobic interaction and then changed the electrode/solution interface, and eventually affects the electrochemical response of FA, confirming from the remarkable oxidation peak current enhancement. For investigation of the electrode properties, CV technique was used at the various scan rates. Electrochemical parameters including diffusion coefficient (D), electron transfer coefficient (α) and ionic exchanging current density (j_o) were determined for the FA at the surface of the electrode. Under optimized conditions, the proposed method showed acceptable analytical performances for FA in terms of linearity (over the concentration range from 0.01 to 1.5 and 1.5 to 10.0 μM), detection limit (2.89 nM), repeatability (1.37%) and stability (13% reduction in peak current after 60 days). After studying on the effect of probable interferences it was found that the method was free of the interferences. Finally, the proposed method was successfully applied for the determination of FA in real samples.     

Platinum/iridium/carbon: a high-resolution shadowing material for TEM,STM and SEM of biological macromolecular structures

Thin Pt/Ir/C coating films (1.5 nm) show a fine granularity and provide a high structural resolution in the transmission electron microscope (TEM) when applied to freeze-dried biological macromolecules. They keep their structure when exposed to atmospheric conditions, without the need of an additional stabilizing carbon layer, in contrast to conventional high-resolution shadowing materials such as Ta/W and Pt/C. However, the correct ratio of the components has turned out to be crucial. When evaporating Pt/Ir/C from the source electrode in an electron-beam-heated evaporator, the ratio of the three elements changes progressively, and, consequently, the properties of such films depend strongly on the mass that has been pre-evaporated. In this paper we present a quantitative analysis of the composition of Pt/Ir/C films by wavelength-dispersive X-ray analysis (WDX) undertaken in association with TEM experiments. We applied Pt/Ir/C shadowing to two regular biological test specimens, the phage T4 type III polyhead and the HPI-layer of Deinococcus radiodurans. It turns out that Pt/Ir/C films containing at least 25% C are three-dimensionally stable on the freeze-dried macromolecular samples. By the dramatically improved resolution power of the latest scanning electron microscopes (SEM) and the invention of the scanning tunnelling microscope (STM), two new surface-sensitive tools for the investigation of biological macromolecular structures became available. The Pt/Ir/C coating has proved to be well suited for STM and SEM imaging of freeze-dried biological structures because of its good electrical conductivity and its direct three-dimensional stability. We compare STM, SEM and TEM images of freeze-dried and Pt/Ir/C-coated polyheads.     

分布式监测系统应用服务器设计

在分析分布式实时监测系统结构及实时数据处理的基础上，提出一种通用实时监测应用服务器设计方案。本应用服务器采有多线程机制，在线采集工业控制的实时数据，通过浏览器可视化组件动态发布设备运转及生产状况信息。本方案具有完善的页面请求、客户请求、以及数据对象的管理和服务功能，其结构灵活，系统维护性强。     

Application of L-DOPA modified carbon nanotubes as a bifunctional electrocatalyst for simultaneous determination of ascorbic acid,adrenaline, acetaminophen and tyrosine

L-DOPA multi-wall carbon nanotube modified glassy carbon electrode (DOPA-MWCNT-GCE) was used as a bifunctional electrocatalyst for simultaneous quantitative determination of ascorbic acid (AA) and adrenaline (AD). Electrochemical experiments show that the modified electrode plays the role of an excellent bifunctional electrocatalyst for the oxidation of AA and AD in two different potentials. The kinetic parameters such as the electron transfer coefficient, α, and the heterogeneous electron transfer rate constant, k′, for the electrocatalytic oxidation of AA and AD at the DOPA-MWCNT-GCE surface were estimated. Through a different pulse voltammetric (DPV) method, the plot of the electrocatalytic current versus AA and AD concentrations emerged to be constituted of two linear segments with different sensitivities. In addition, detection limits of 1.5 μM for AA and 0.62 μM for AD were obtained. In DPV, the proposed bifunctional electrocatalyst could separate the oxidation peak potentials of AA, AD, acetaminophen (AC) and tyrosine (Tyr) present in a mixture though, at the bare GCE, the peak potentials overlap. Finally, DOPA-MWCNT-GCE was satisfactorily used for the determination of AA, AD, AC and Tyr in pharmaceutical preparations.     

选煤厂PLC应用系统设计选型浅析

以近几年实践经验为基础,对选煤厂基于PLC的控制系统进行了分析和研究,探讨了选煤行业PLC应用系统的设计选型原则,期望能推动行业自动化系统设计整体水平再上新台阶.