目前,数字控制技术被大量应用到实际生产过程中.PLC电气控制技术具有经济、高效的特点,以此备受重视.组合机床是对于某些指定工件,根据指定工序实现批量加工的组合专用设备,此种设备具有较高的生产效率,并且机床结构较为复杂,要求电气设计稳定.基于此,文章就在组合机床中使用PLC技术,分析组合机床中PLC电气控制系统的设计和使用.
随着经济全球化进程的不断推进,经济发展也是日益强大,经济工作自然也是受到广大求职者的追捧.众所周知,高职院校与普通高校的区别在于,高职院校旨在培养具有专业技能的应用型人才,高校会计电算化课程在互联网的推进下,又进一步对广大师生与企业提出新的要求,文章将从当代高职教育中国学徒制的内涵,高职电算化人才培养的现状出发,并提出几点关于当代学徒制人才培养在高职会计电算化教学中的具体应用建议.
Ethoxyethyl cyanoacetate is a principal raw material for making the ethoxyethyl-α-cyanoacrylate instantaneous adhesive with low whitening and low oder and was synthesized using transesterification with 2-ethoxyethanol and ethyl cyanoacetate as the raw materials and dibutyltin dilaurate as catalyst.The effect of the reactant mole ratio,reaction time,and catalyst on the product yield was investigaled.The results indicated that the optimum conditions are mole ratio of 2-ethoxyethanol to ethyl cyanoacetate 2:1,mass ratio of catalyst to ethyl cyanoacetate reactant 2.5% and reaction time 10 h.The product yield can reach 85%and the purity is 97.3%.
通过二滩水电站水垫塘底板和护坦多年的抗冲磨修补工程实践,对环氧砂浆修补材料的抗冲击磨蚀性能和施工工艺等进行了持续改进,研制出一种低放热、低热变形温度、耐冲击、抗磨蚀的JME改性环氧砂浆抗冲磨修补材料。有效地解决了二滩水垫塘高温环境对施工的要求和高水头、高流速环境下水垫塘底板、护坦的薄层破损修补问题,对维护电站的安全运营起到了重要作用。
A series of waterborne polyurethane adhesives (WPUAs) for laminated composites was synthesized from isophorone diisocyanate (IPDI),polybutylene adipate (PBA),dimethylolpropionic acid (DMPA),KH550,etc.And the influences of the content of KH550 on the properties of WPUA was discussed. The results showed that when the amount of KH550 increased,the viscosity of the WPU emulsion increased and the stability of WPUA decreased gradually.Moreover,the water resistance of film was much better than that of unmodified WPUA,the tensile strength of film and the T-style peel strength of laminated composites increased when the amount of KH550 increased.
The fast cruable and storage stable ketone-oxime type RTV-1 silicone sealant was prepared with α,ω-dihydroxy polydimethyl siloxane,ketoximosilane crosslinking agent,special curing accelerator and storage stabilizer.The results showed that when the content of special curing accelerator was 0.4% by weight,the tack-free time was shortened to three minutes from ten minutes and the deep section curing speed was increased from 3.1 mm/24 h to 3.4 mm/24 h.The conventional mechanical properties and performance after hygrothermal aging (85℃,85% RH for 1 000 h) were also increased greatly.The storage life was improved from 3 days to 14 days in 70℃ accelerated aging test by adding storage stabilizer.The producing process is stable and easy for operation.
In recent years,the environment-responsive microspheres have attracted much attention due to their widely application prospects in various fields.The recent research progress of environment-responsive microspheres at home and abroad was reviewed and the microspheres with a single function and multi-function were classified described in this paper.At the same time,systematic summary of the practical application of microspheres was presented.Finally,the research directions of environment-responsive microspheres in future were also prospected.
一元复始,万象更新.伴随着清脆的新年钟声,沐浴着冉冉升起的朝阳,《粘接》杂志编辑部全体同仁向每一位关心和支持我们的朋友们,致以新年的问候和祝福:祝您在新的一年里工作顺利,健康快乐.
<正>人无信不立,企业亦是如此。市场经济的实质就是信用经济,其发展程度越高越要求企业讲求诚信经营,只有诚实守信,才能以信用在市场生存、发展。可见,诚实守信是企业发展的动力源,应该在当前企业战略转型中占据重要地位。企业以诚信在市场生存、发展;不讲诚信的企业,不可能维持长久。诚信是企业的无形财富,是市场经济的黄金法则,更是企业管理、生产经营的行为准则。企业对外都声称诚信经营,可做得却不够。因此,企业应切实坚持"诚信为先,以信誉求发展"的理念,以推动企业的可持续发展。
In this paper,using phosphoric acid and wheat starch as the main raw materials the esterified starch adhesive was prepared.The effects of contents of starch and phosphoric acid,reaction temperature,reaction time and pH value on the properties of the adhesive were investigated.In addition,the structure of esterified starch adhesive was characterized by FT-IR.The results showed that the overall performance of the esterified starch adhesive was optimal under the conditions of 7 wt% wheat starch,6 wt% phosphoric acid,reaction time 4 h,reaction temperature 70 ℃ and pH=5.
Polyaniline is one of the most widely used conductive polymer materials,and is also a kind of new materials with special functions.It has been applied in stealth materials,anticorrosion materials,antistatic materials and so on.This paper mainly expounded the structure and conducting mechanism of polyaniline as well as the effect of some factors,such as different acid doping and polymerization process,on its conductive properties,at the same time,and looked forward to the promising application of conductive polyaniline.
The underwater curing agents (JA-I,JA-I S,and JA-I D) and the high-flexible toughening agent (JE-312) were utilized to design the crack repairing adhesive.The obtained repairing adhesive can bond the wet surfaces,repair the wet road cracks with large size and meet the requirements of Chinese standard GB50367.The effect of curing agents and toughening agent on the curing rate and tensile properties was carefully studied and the appropriate curing system and the toughening agent content were suggested.
<正>1前言自由基聚合与α-烯烃的配位聚合是2种在工业上极重要、应用很广的合成方法。但是,在自由基中间体中由于存在二分子终止(自由基再结合及歧化)现象,所以长期以来普遍认为,从原理上讲,自由基聚合的精密控制是很困难的。自20世纪80年代以来,研究者们开展了"精细自由基"(活性自由基)聚合的研究(见图1,2)。日本泽本光男等进行了过渡金属催化自由基聚合研究(图3),使这一课题迎来了新局面。泽本等人认为,以下3点值得关注:
The effects of environmental condition,mainly the temperature and humidity,on the skin drying time,curing rate,green shearing strength and adhesion performance were investigated.The results showed the temperature and relative humidity of construction environment of the adhesives Sika 265,221 and 252 should be 15-35 ℃ and 30%-70%,respectively,for the components having adhesion level A1 and level A2;and the construction environment temperature and relative humidity should be 10-40 ℃ and 10%-80%,respectively,for the components mainly used for sealing function.
In the article,E-51 epoxy resin was used as the main material,while diethylenetriamine and homemade modified polyamides 380T were used as the curing agent. The optimum experimental formulation and conditions were determined through the study of proportion of 380T and diethylenetriamine,curing agent amount,and type and content of fiiler.The tensile strength and shear strength of the structural adhesive after curing for 7 days at room temperature reached 52 MPa and 19.2 Mpa,respectively,when the proportion of E51,380T,diethylenetriamine and quartz sand was 100:26:4:200～300 by weight.The two compoment epoxy structural adhesive has high mechanical properties,bonding properties and toughness,and better thixotropy and wetting properties.
The surface of HTV SR was treated with plasma.The effect of medium gas,treating time and standing time on the chemistty state of surface and the bonding properties between silicone rubber and hydroxy-terminated polybutadiene polyurethane (HTPB-PU) was studied.The results indicated that after plasma treating some new chemical groups were generated on the surface of silicone rubber and the bonding properties between silicone rubber and HTPB-PU was improved obviously.The effect of the medium gas kind,treating time and standing time on the bonding properties was not obvious.
The hydrogenated mitrile butadiene rubber (HNBR) based sealant with better resistance to thermo-oxidative ageing was prepared by compounding HNBR as the basic rubber material,fillers,tackifying resins and plasticizers etc.The effects of different brand HNBR,fillers,resins and plasticizers on the sealant performance were studied by single-factor experiments.The optimization of formulation was carried out by orthogonal experiments.The results showed that when the formulation by weight contains 15% Therban A3406,50% fumed silica,36% phenolic resin and 2.5% tricresyl phosphate,the obtained HNBR-based sealant has excellent comprehensive performamce.
<正>2013年我国化工产品对外贸易可能会面临严峻的挑战,在已经预见到困难的情况下,未雨绸缪、早思量、早准备就成为当务之急。有这样一则故事,一个人到某地开了家餐馆,另一个人见餐馆很赚钱,就在旁边开了家旅店,再一个人过去开了个电影院,后来当地的配套设施逐渐完善,大家生意都很兴隆。而与之形成对比的是,一个人到某地开了家餐馆,另一个人见餐馆很赚钱,就又
<正>日前,一位化工企业安监部门的朋友忧虑地对笔者说,他们在安全检查中,常常是检查哪些项目,哪些部位,被检查的企业早已安排妥当,且由企业的领导和迎检人员全程陪同。碍于面子,很多时候安监人员只好被动地"牵着鼻子走"。这样的安检确实让人感到忧虑。企业为什么要设定好安检路径、预先设定检查地点岗位?显然是怕被查出问题。这种检查路径、地点由被检单位说了算,无疑会漏掉企业真正的不足之处,
