电沉积铁镍铬合金工艺参数对镀层铬含量的影响

给出了电沉积铁镍铬合金镀层的镀液配方和操作条件：着重研究了配合剂浓度，电流密度三价铬离子浓度，温度和酸度对镀层Ｃｒ含量的影响；通过优化工艺参数，得到了铬含量１５％￣４０％合金镀层。     

铝上铬磷化工艺及促进剂的研究

选择了铬磷化工艺中适宜的溶液组成，并研究了铬磷化的工艺条件和转化膜层的性质，优选了铬磷化液的促进剂。该促进剂能加速铬磷化的反应速度，细化膜层和提高抗蚀性，已明显地提高了转化膜的质量。另外，还对铬磷化过程的电位－时间曲线进行了探讨。     

碳钢与不锈钢表面高浓度渗铬法

在氩气气氛下，应用固体渗铬填料法对碳钢、不锈钢作了表面高铬浓度的渗铬处理，探讨了渗铬温度、时间和渗铬组分对渗层表面铬含量、厚度，试样增重和物相组分影响，碳钢、不锈钢的表面渗铬浓度分别达８０－９４ｗｔ％和７０－８２ｗｔ％。     

镀锌层三价铬银白色钝化工艺现状及无铬钝化发展趋势

介绍了镀锌层银白色三价铬钝化以及无铬钝化的工艺现状和成膜机理,并阐述了未来发展的趋势。指出了三价铬钝化工艺不能从根本上解决铬元素的环境污染问题,无铬钝化工艺为大势所趋,以硅酸钠为主要成膜剂,在镀锌件表面形成银白色钝化膜的无铬钝化工艺具有可行性,应用前景广阔。     

无锡镀铬层及铬水合氧化物层中铬的快速测定

研究用化学退镀法在Ｈ２Ｏ２介质中用５％氢氧化钠溶液退除无锡薄钢板上铬水合氧化物层，用０．５％六次甲基四胺盐酸溶液退除金属铬层，采用正丁醇作增感剂用空氧乙炔火焰原子吸收法测定铬的灵敏度，检出限０．０６μｇ／ｍＬ。本法与日本Ｊ１ＳＧ３３１５相比，快速、灵敏，操作简便，精密度相当。     

高耐蚀性低铬钝化工艺的应用

分析了低铬钝化膜不及高铬钝化膜的原因，提出控制钝化液成分来提高低铬钝化质量的方法，介绍了一种高．耐蚀低铬彩钝化溶液配方。     

铜铬合金直接加铬熔炼和铸造

铬青铜系指含Ｃｒ０．４％～１．０％的铜基合金。是难于熔炼的合金，多以变形材料使用。经试验表明，采用中频感应电炉大气下熔炼，铬以纯金属加入，可获得性能优良的铸造Ｃｕ－Ｃｒ合金。     

粉末冶金高纯铬和铬合金溅射靶材烧结工艺研究

介绍了不同加工方式对铬靶烧结密度的影响.在机压过程中,采用双向压制,不添任何成型剂和脱氧剂.机压+真空烧结铬环靶材密度为78%～80%;冷等静压+真空烧结铬板靶材密度大于82%;而经轧制后,铬板靶材密度提高到90%～95%;铬合金靶材采用热压方式,其密度大于98%.通过优化烧结时间和烧结温度等工艺参数,铬环靶材的烧结成本大大降低.     

铬刚玉物相的研究

对铬刚玉的物相进行较深入研究，鉴定了铬刚玉中的物相，进一步证实铬刚玉中氧铬与氧化铝形成置换固液体，Ｃｒ＾３＋取代Ａｌ＾３＋存在刚玉晶格中，并从理论加以阐述，还首次在铬刚玉中鉴定的β－Ａｌ２Ｏ３。     

无铬达克罗涂料的研究进展

无铬达克罗技术是一种环境友好的高效防腐蚀表面处理工艺。综述了无铬达克罗涂料中铬酐替代物的钝化性能及其研究进展,梳理了无铬达克罗涂料主要成分鳞片状锌粉的制备工艺及国内外研究现状,指出了高性能无铬钝化技术、高活性和大径厚比鳞片状锌粉的制备技术是今后无铬达克罗技术的主要研究方向。     

Agglomeration behavior of chromia nanoparticles prepared by amorphous complex method using chelating effect of citric acid

Chromia (Cr₂O₃, chromic oxide, Eskolaite) nanoparticles were prepared by amorphous complex method using citric acid as a chelating agent. As a precursor for chromic oxide particle, dried gel with a three-dimensional network consisted of the molar ratio of [citrates]/[chromium ions]=2:1 was prepared. Finally, chromic oxide nanoparticles were formed by calcination of precursor gel at 700 °C for 2 h. Obtained chromic oxide particles were characterized by thermogravimetric and differential thermal analysis, X-ray diffraction, field emission scanning electron microscopy, and Brunauer–Emmett–Teller surface area measurement. It turned out that chromic oxide nanoparticles showed highly agglomerated structure consisted of weakly attached primary particles with each other by van der Waals and capillary adhesive forces. The size distribution of the individual particles was about 20–50 nm. Estimated average particle size from BET surface area was 29.21 nm. The reason for the formation of highly agglomerated structure was discussed.     

pH response of carboxy-terminated colorimetric polydiacetylene vesicles

Carboxy-terminated polydiacetylene vesicles are known to undergo dramatic color transitions in response to exposure to external stimuli such as pH, temperature, and receptor-ligand binding. FTIR spectroscopy was used to identify the breakdown in the interfacial hydrogen-bonding interactions of the carboxylic acid headgroups of polymerized 10,12-tricosadiynoic acid (TRCDA) vesicles in aqueous solution during pH chromic transition. The headgroup structure was monitored as the chromic transition takes place and the dissociation dependence of the pKa was determined. Due to the attenuated acidity of the interfacially confined carboxy groups, which exhibit pKa values in the range 9.5-9.9, it was found that the deprotonation-triggered blue-red chromic transition occurred in the pH range 9.0-10.1 and that the mechanism of the transition required interaction with the surface carboxyl group, which is of importance in the design of a biochromic mechanism using PDA assemblies. Transmission electron microscopy and FTIR spectroscopy revealed that the surface ionization and the pH-induced chromogenic transition was also accompanied by a dramatic vesicle-planar morphological transition alongside subtle changes to the alkyl chain conformation and packing. A two-step mechanism was implicated as causing the chromic transition that first involves surface deprotonation and then specific cation binding, which can aid the design of sensitive surface-ligand chemistry for new PDA structures.     

有机敏感变色功能材料的研究

综述了有机敏感变色材料的基本类型，探讨了材料的各种变色效应光致变色，热致变色，电致变色和压致变色等的内在关联，总结了有机敏感变色材料的基本分子结构类型并讨论了分子结构与敏感变色性质之间的关系。     

Surface characterization and platelet adhesion studies on polyethylene surface with hirudin immobilization

Hirudin, a protein composed of 65 or 66 amino acid, is a newly risen anticoagulant agent and has been considered as the most potent thrombin inhibitor. Hirudin can block the active site of thrombin by means of its carboxylic acid reaction with the active regime of thrombin, and becomes a tightly bound complex, and thus controls the formation of thrombus. Hirudin was covalently immobilized onto the water-soluble carbodiimide preactivated and chromic acid oxidized PE surface. Surface chemistry analysis indicated that a certain amount of carboxylic acid groups was generated on the polyethylene surface after oxidation with chromic acid solution. The amount of carboxylic acid functional group increased with the oxidation time. In addition, polyethylene surface was etched by chromic acid solution, and a rougher surface was created. The morphology of oxidized polyethylene surface was similar to each other among the samples with oxidation time from 1 to 8 min. ESCA results indicated the number of hirudin molecules immobilized was constant at the reaction time studied. In vitro platelet adhesion assay indicated the number of adhered platelets on the oxidized polyethylene surface increased significantly after oxidation. In contrast, surface with hirudin immobilization showed a reduction in adhered platelet density than the chromic acid oxidized counterpart due to the decrease of platelet-activating capability by the hirudin–thrombin complex and the differences in the adsorbed protein composition. © 2001 Kluwer Academic Publishers     

铬酸酐物料桶自动紧箍封盖机设计

目的 针对铬酸酐有腐蚀性与有毒有害性，及其手动封装环境给人身体带来安全隐患的问题，迫切需要设计一种安全、高效的铬酸酐物料桶封装工艺。方法 提出一种基于三坐标桁架的自动封装系统，其中机械臂实现自动抓取桶盖完成桶盖自动上料的工序，螺杆和螺母供料器由重力效应完成螺杆和螺母顺序供料的工序，螺栓封盖机构完成螺栓紧固物料桶桶盖的工序，从而实现三坐标绗架封装系统的自动封装功能，并通过数字模拟和试验的方式验证封装工艺的合理性。结果 在封装环节，精密设计的螺栓封盖机构实现了自动供货和高负载精确的螺栓封装工艺。设计的自动封装系统的封装速度高达1.2个/min，试验阶段封装成功率高达100%。结论 该设备结构合理，在保证铬酸酐物料封装质量的前提下，合理规避了人工生产带来的安全隐患，推动了化工企业的自动化进程，为桶的自动封装提供了一种解决方案。     

Homogeneous arc ablation behaviors of CuCr cathodes improved by chromic oxide

Cathode ablation is one of the dominant limitations for extending the maximum operating time of arc heaters.In this work,the arc ablation behaviors and mechanisms of commercial CuCr10,CuCr25,and CuCr50 cathodes were investigated for pure copper and pure chromium cathodes.The discharging homo-geneity was improved with the increase of chromium content in the cathodes,which was attributed to the formed chromic oxide layer.The CuCr50 cathodes exhibited the lowest ablation rate with a reduction of 27.0％ compared to the copper cathodes.The chromic oxide formed in the pit protected the bottom matrix,leading to a homogeneous ablation process.The mechanism for the improved homogeneous ablation behaviors of the CuCr50 cathodes was proposed and featured by the suppression of deep pits and the dispersion of arc foot.Future attention will be focused on designing composite cathodes with an anti-ablation surface layer and a good conductive matrix.     

Design and implementation of a navigation control system for slag pot carriers based on combination of active RFID and WiFi technologies

The supervision and management of staff and equipment will always result in performance enhancement. In Mobarakeh Steel Company which is located in Iran, the produced slag at electric arc furnaces was transported using slag pot carriers. In the absence of a control system to supervise the performance of these vehicles, managing replacement of slag pots was a challenging and difficult task. Although maintenance of slag pot carriers was expensive and needed specific expertise, there was no online supervisory system to avoid probable failures in vehicles. In order to improve the performance of the supervisory system of the slag pot carriers, a WiFi network was developed in the trajectory of slag pot carriers. Furthermore, the installed RFID-tags alongside the path of the travelling carriers have been read via the RFID-readers installed on the slag pot carriers. Then, the position and speed of the slag pot carriers were calculated and transmitted to the developed software. The performance of the slag pot carriers was improved by implementing the proposed new technology. In addition, stop time rate caused by obstruction of the roads was reduced by 80%. Thereby, systematic, efficient, and optimized slag pot replacement and personnel rotation schedules were developed and the desired productivity was achieved..     

超高分子量聚乙烯纤维复合表面改性及其橡胶基复合材料的力学性能

针对超高分子量聚乙烯(UHMWPE)纤维与基体之间界面结合强度低的问题,采用超声波结合铬酸溶液氧化的复合工艺对UHMWPE纤维进行表面处理,并将处理后的纤维加入到天然橡胶(NR)中制备短切UHMWPE纤维/NR复合材料。结果表明:复合改性工艺可有效增加纤维表面粗糙度及表面含氧官能团含量,最佳改性工艺条件为:按照重铬酸钾、水及浓硫酸的质量比7∶12∶150配置铬酸溶液,将含有一定质量UHMWPE纤维的铬酸溶液放入35℃的超声波清洗仪中氧化5min,其中超声波频率为100kHz。与纯NR样品相比,在UHMWPE纤维与NR的质量比为0~6∶100范围内,随着处理后短纤维含量的增加,复合材料的拉伸强度逐渐减小,最大损失量达到50%;复合材料的硬度不断增大,最大增加量达到96%;复合材料的撕裂强度先增大后减小,在UHMWPE纤维与NR的质量比为5∶100时达到最大值,最大增加量达到49%。     

Effects of a combined admixture of slag powder and thermally treated flue gas desulphurization (FGD) gypsum on the compressive strength and durability of concrete

In this paper, the effects of a combined admixture of slag powder and thermally treated flue gas desulphurization (FGD) gypsum on the compressive strength and durability of concrete were explored. The gypsum was baked at a proper temperature of 200°C for 60 min; it was then mixed with slag powder to form the type-G slag powder in which SO₃ content was controlled at the optimum ratio of 3.5%. Concretes containing the type-G slag powder or ordinary slag powder were further contrasted on the compressive strength and durability. The results showed that the compressive strength, resistance to chloride, and resistance to gas permeability of concrete with the type-G slag powder were higher than that with ordinary slag powder. Additionally, there were no negative effects on concrete against sulfate attack. The combination of the two byproducts, slag powder and thermally treated FGD gypsum, provided synergistic benefits above that of ordinary slag powder alone.     

简单蚀刻法制备具有可控高度的金属纳米线阵列

采用多孔阳极氧化铝(AAO)作为模板,运用电化学沉积法在模板的微孔中组装金属Ni纳米线,然后用磷铬酸蚀刻表层AAO模板,暴露出规整有序、具有可控长度的Ni纳米线阵列.分别用SEM、TEM与SAED对Ni纳米线阵列进行了表征.研究了蚀刻时间与AAO模板质量的减少及暴露出来的Ni纳米线阵列长度之间的关系.结果表明,磷铬酸是较NaOH溶液更为温和有效的AAO模板蚀刻剂,通过控制模板溶解时间,可以实现对裸露于AAO模板外纳米线长度的精细有效控制.该蚀刻方法普遍适用于以AAO为模板所制得的准一维纳米阵列结构.