共查询到20条相似文献,搜索用时 46 毫秒
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采用直流电弧等离子体法制备了铁、镍、钴及其合金的磁性超微粒子 (UFP) ,平均粒度小于 10 0nm。利用金属或合金超微粒子 ,选择适当的表面活性剂和载液 ,制备了高粘度磁性液体密封材料 (MF) ,常温 (2 5℃ )粘度为 (2 .6~ 3.8)× 10 5mPa·s,高温 (70℃ )粘度为 (1.5~ 2 .2 )× 10 5mPa·s ,室温下饱和磁化强度为FeMF 40 3~ 6 41G/g ,NiMF15 1~ 188G/ g ,Fe-NiFM 44 2~ 6 91G/g。使用高粘度磁性液体密封材料和具有补偿磁流体功能的密封器件 ,实现了对抽油泵的防泄漏密封 ,提高泵效 2 0 %左右 ,延长了泵的运行周期 相似文献
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胶束光度法测定非晶态FeNiCr合金中的镍 总被引:3,自引:0,他引:3
在pH =8 .0、HCl tris缓冲溶液和Tween80胶束介质中 ,研究了 1 亚硝基 2 萘酚 (NN)与Ni(Ⅱ )的显色反应。建立了胶束光度法测定微量Ni(Ⅱ )的新方法。结果表明 ,Ni(Ⅱ ) NN配合物的最大吸收波长为 4 5 5nm ,摩尔吸光系数为1.0 1× 10 4 L/ (mol·cm) ,检出限为 0 .0 4mg/L ,有色溶液的吸光度与Ni(Ⅱ )量在 0 .2~ 1.0mg/L范围内符合比耳定律 ,加标回收率为 96 .2 %~ 10 3.1% (n =6 )。测定了非晶态FeNiCr合金钢中的镍。 相似文献
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7 .1.5 操作条件及其影响( 1)铁丝镀锌线的一些技术参数 (见表 10 )表 10 线材镀锌线的一些技术参数线材规格/mm自动线长度/m电镀槽数/个镀槽尺寸/m同时装载数/根线材速度/(m·min- 1)1 .2 5~ 0 .56 6~ 72 .0× 0 .6 536 382 .4 1~ 1 .4 7(一般 ) 6~ 72 .5× 0 .7532 2 44.1 9~ 2 .776~ 7 6~ 72 .5× 0 .6 52 4 1 8 ( 2 )pH值 镀液的pH值 ,尤其是阴极附近电解液的pH值 ,对镀层耐蚀性和光亮度有很大影响。若pH值过高 ,阴极析氢的结果将导致阴极附近形成氢氧化物或碱式盐沉淀 ,从而使阴极表面形成粗糙甚至疏松… 相似文献
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采用溶胶 -凝胶 (Sol -Gel)工艺在普通Na -Ca -Si玻璃基体上成功地制备出高c轴择优取向性、高可见光透光率以及高电导率的Al3 + 离子掺杂型ZnO薄膜。利用SEM、XRD以及UVS光谱仪等分析方法对不同工艺下制备的薄膜进行了研究 ,结果显示 ,所制备的薄膜为纤锌矿型结构 ,表面均匀、致密 ,薄膜材料晶粒尺寸大约为 5 0~ 2 0 0nm左右 ,薄膜可见光透光率最大可达 99% ;对薄膜的厚度以及电学性能进行了测定后发现 :单次镀膜厚度约为 3 0~ 5 0nm ,Al3 + 离子掺杂型氧化锌薄膜的电阻率在 2 .5 2× 10 -3 ~ 2 .94× 10 -3 Ω·cm范围内 ,其霍尔系数在 6.2 5× 10 -7~ 2 .3 6× 10 -7cm3 /C范围内 ,载流子浓度在 1×10 2 5~ 2 .64× 10 2 5cm-3 范围内 ,霍尔迁移率在 2 .48× 10 -4 ~ 8.0 3× 10 -5cm2 /V·s范围内 ,在太阳能电池透明光电极领域中极具潜在的应用价值。 相似文献
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本文介绍了等度高效液相色谱(HPLC)测定大豆异黄酮中二种主要成份:大豆甙元(Daidzein)和金雀异黄酮(Genistein)的方法。采用Atlantis C18色谱柱和EasyGuard C18,保护柱;以甲醇:0·1%醋酸(pH3·11)=51·5:48·5(v/v)为流动相;检测波长λ=254nm;流速1mL/min。在测定范围内(10-200ng)峰面积与质量浓度线性关系良好。大豆甙元和金雀异黄酮的相关系数分别为0·9984,0·9997·两组份回收率为97·0—102·92%· 相似文献
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改性PVA超滤膜的制备与性能研究 总被引:12,自引:3,他引:9
选用聚乙烯醇、水、乙酸、硫酸铁等为原料 ,用相转化法制备了亲水性超滤膜 .在一定范围内研究了各种不同浓度的膜液组成对超滤膜性能的影响 ,确定了较佳的铸膜液组成 (质量分数 )为 :8%PVA ,6 %乙酸 ,1 5 %~ 2 %硫酸铁 .用此铸膜液制备的超滤膜 ,在操作压力为0 30~ 0 4 5MPa下 ,处理浓度为 10 0 0mg·L- 1的O/W型乳化液 ,透液速率可达 4 3L/(m2 ·h)以上 ,其除油率可达 92 %以上 .研究还表明 ,PVA超滤膜中添加适量硫酸铁 ,可改善膜的结构和耐水性能 . 相似文献
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《上海计量测试》2001,28(3)
根据《中华人民共和国计量法》 ,我局已对下列企业申报的计量器具新产品样品进行样机试验 ,考核合格 ,特此公告。单位名称 :鸿熙电子 (上海 )有限公司负责人 :吴 东地址 :浦东新区东陆路 185 5号电话 :5 85 4116 9 邮编 :2 0 12 0 6证号 :(2 0 0 1)沪技监计样字第 5 7号产品名称 :数字多用表型号 :HH2 10 7技术指标 :直流电压 :2 0 0mV~ 2 0 0V ± (0 .5 %读数 1字 )10 0 0V± (0 .8%读数 2字 )交流电压 :(4 5~ 2 0 0Hz)2 0 0mV ,70 0V± (1.2 %读数 3字 )2~ 2 0 0V± (0 .8%读数 3字 )电阻 :2 0 0Ω± (0 .8%读… 相似文献
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《中国标准化》2003,(Z1)
最近 ,英国食品主管部门首次为儿童食用盐提出建议。这个新的建议是基于营养科学咨询委员会(SACN)的最新报告结果。建议按照不同年龄为儿童每天摄入食盐规定了最大限量。新的建议如下 :·对 0~6个月年龄段的儿童 ,每天食用盐应低于 1g;·对 7~ 1 2个月年龄段的儿童 ,每天食用盐为1g;·对 1~3岁年龄段的儿童 ,每天食用盐为 2g;·对 4~6岁年龄段的儿童 ,每天食用盐为 3g;·对 7~1 0岁年龄段的儿童 ,每天食用盐为 5g;·对 1 1~1 4岁年龄段的儿童 ,每天食用盐为 6g。据调查 ,目前 4岁和 4岁以上的儿童每天食用盐的平均值不同程度高于上… 相似文献
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《International journal for numerical methods in engineering》2018,113(9):1488-1506
In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method. 相似文献
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Standards are the basis for production enterprises to organize production ex-factory inspection trade 《中国标准化(英文版)》2008,25(1):24-25
Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.…… 相似文献
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A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa. 相似文献
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On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.…… 相似文献
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Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß. 相似文献
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C. Qihong W. Zhan‐Wen J. Yi J. Yehua L. Fei F. Hanguang 《Materialwissenschaft und Werkstofftechnik》2014,45(7):582-590
In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M2(B,C), (W,Mo)2(B,C), M3(B,C), M23(B,C)6 type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm2. The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K1 mill housing of bar mill. 相似文献
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Dimiter Hadjistamov 《材料科学与工程:中英文B版...》2019,(2):56-65
The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ... 相似文献
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《中国标准化(英文版)》2014,(4)
正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from 相似文献
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《中国标准化(英文版)》2014,(5)
正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively. 相似文献