共查询到20条相似文献,搜索用时 62 毫秒
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我国首台25MN单动轻合金型材挤压机试制成功太原重型机械集团公司为江南铝业公司设计、制造和安装的我国首台25MN单动轻合金型材挤压机,于1994年8月18日在江苏省昆山仪表成套厂通过了总装负荷试车,成功地挤出了合格的硬铝合金棒材LY12Φ150mm、... 相似文献
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沈阳重型机器厂自1991年以来已为天津大港铝合金总厂等11个厂家设计制造了12台16MN、12.5MN、8MN、5MN铜、铝挤压机,同时还承担了挤压机技术改造及配置装置。为挤压机的设计制造做出了贡献。在消化吸收国内外先进技术的基础上,挤压机技术水平不断提高,主要有以下几点。 相似文献
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江苏太仓市华宇机械有限公司设计制造出中国国产第一台双头直线电机式牵引机,安装于鑫鑫铝业有限公司的3600吨铝型材挤压机上,自2002年10月至今运行情况良好。 双头牵引机在国外的铝挤压机上应用较多,也曾有外国公司到中国作技术交流时介绍过,只是在中国尚未有企业引进过双头牵引机,以往引进的牵引机都是单头牵引机。 江苏太仓市华字机械有限公司的前身,原太仓通用设备厂曾是国内最早制造生产铝挤压机用牵引机和铜管挤压机用牵引机及其它铝铜挤压的辅助设备的工厂。 相似文献
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试验研究建立了同一试料溶液连续、同时测定铂饰品中各成分的分析方法。主体Pt以氯铂酸铵称量法及火焰原子吸收光谱(FAAS)法或电感耦合等离子发射光谱(ICP-AES)法测定滤液中残留Pt进行补差而测定。主成分Pd,Au,Ag,Cu和焊料成分Ni,Zn,Fe以FAAS法或ICP-AES法测定。其方法回收率分别为:Pt99.9%~100%;Pd99.3%~99.7%;Au99.5%~l01.5%;Ag98.0%~100%;Cu97.7%~99.3%;Zn98.0%~99.0%;Ni94.0%~105%;Fe95.0%~99.0%。实际试样分析时,各成分质量分数之和一般在99.12%~l01.2%之间,接近于100%,间接说明方法的可靠性。本法适用于Pt-Pd二元体系和Pt-Pd-Au-Cu多元复杂体系的铂饰品的破坏分析,可用于校正X荧光光谱法无损检测铂饰品的分析结果。 相似文献
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稀土金属中14种非稀土杂质的ICP-MS法同时测定 总被引:1,自引:0,他引:1
本文研究了用 ICP- MS仪器同时测定稀土金属中 Mg、Al、Ti、Cr、Mo、Mn、Co、Ni、Cu、Zn、Pb、W、Nb、Ta等 14种非稀土杂质。研究了各稀土基体对被分析元素的基体效应 ,选择了相匹配的内标元素。比较了标准曲线法与标准加入法的测定结果。确定了用内标元素校正基体效应及仪器漂移 ,以标准曲线法直接测定。进行了加料回收和精密度实验 ,回收率在 94%~ 113%之间 ,RSD<10 %。被分析元素的检出限为 0 .0 1~ 0 .2 0 ng/ m L,测定下限为1~ 2 0 μg/ g。 相似文献
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MR Thompson R Venkatesan K Kuppusamy A Celik W Lin DK Kido EM Haacke 《Canadian Metallurgical Quarterly》1999,210(1):253-259
An insertable head gradient coil with a maximum gradient amplitude of 45 mT/m and a rise time of 150 musec along all three major axes was used to collect high-spatial-resolution, single-shot, spin-echo, echo-planar, diffusion-weighted magnetic resonance images with b values ranging from 0 to 2,200 sec/mm2. Improvements in spatial resolution allowed better visualization of large white matter tracts and their relation to adjacent anatomic structures. Excellent contrast and anatomic detail were revealed for most structures in the brain when a sufficient number of acquisitions were collected. 相似文献
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Agar dilution MICs of 10 agents against 410 non-Pseudomonas aeruginosa gram-negative nonfermentative rods were determined. MICs at which 50 and 90% of the isolates were inhibited, respectively, were as follows (in micrograms per milliliter): sparfloxacin, 0.5 and 8.0; levofloxacin, 1.0 and 8.0; ciprofloxacin, 2.0 and 32.0; ofloxacin, 2.0 and 32.0; D-ofloxacin, 32.0 and > 64.0; ceftazidime, 8.0 and 64.0; piperacillin with or without tazobactam, 16.0 and > 64.0; trimethoprim-sulfamethoxazole, 0.5 and > 64.0; imipenem, 2.0 and > 64.0. With the exception of those for Stenotrophomonas maltophilia, Burkholderia cepacia, and Alcaligenes faecalis-A. odorans, agar dilution MICs for all strains tested were within 1 dilution of inhibitory (bacteriostatic) levels as determined by time-kill methodology. 相似文献
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JC Leonard HL Drwinga CH Kim LH Toji PK Bender RA Mulivor JC Beck 《Canadian Metallurgical Quarterly》1997,46(3):530-534
The erm family of 23S rRNA adenine-N6-methyltransferases confers resistance to all macrolide-lincosamide-streptograminB (MLS) antibiotics, but not all MLS antibiotics induce synthesis of Erm methyltransferase with equal efficiency in a given organism. The induction efficiency of a test panel of MLS antibiotics was studied by using two translational attenuator-lac reporter gene fusion constructs, one based on ermSV from Streptomyces viridochromogenes NRRL 2860 and the other based on ermC from Staphylococcus aureus RN2442. Four types of responses which were correlated with the macrolide ring size were seen, as follows: group 1, both ermSV and ermC were induced by the 14-membered-ring macrolides erythromycin, lankamycin, and matromycin, as well as by the lincosamide celesticetin; group 2, neither ermSV nor ermC was induced by the 12-membered-ring macrolide methymycin or by the lincosamide lincomycin or the streptogramin type B antibiotic ostreogrycin B; group 3, ermSV was selectively induced over ermC by the 16-membered-ring macrolides carbomycin, chalcomycin, cirramycin, kitasamycin, maridomycin, and tylosin; and group 4, ermC was selectively induced over ermSV by the 14-membered-ring macrolide megalomicin. These data suggest that the leader peptide determines the specificity of induction by different classes of MLS antibiotics and that for a given attenuator, a major factor which determines whether a given macrolide induces resistance is its size. 相似文献
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