碳纤维增强受电弓滑板制备及其摩擦磨损性能

本文以连续碳纤维和短切纤维为增强相,利用热压技术制备了碳纤维增强受电弓滑板。对试样进行电阻测试、冲击试验以及载流磨损试验,利用SEM对冲击断面和磨损形貌进行观察。结果表明,实验制备的受电弓滑板的电阻率低、抗冲击性能良好,具有良好的抗折抗压能力,能够满足国标对目前广泛使用的受电弓滑板的性能需求;试样的磨损率随着载流密度的提高而逐渐增大,摩擦系数逐渐减少;磨损率随着摩擦速度的增加有所增大,基本呈线性增长;在定载荷70N的条件下,v≤20m/s,J≤80A/cm2时,载流效率均高于75%;且随着电流密度以及摩擦速度的增加,载流效率降低;在J=80A/cm2条件下,载流效率随着载荷的增加而明显变好。碳纤维增强受电弓滑板的载流摩擦磨损形式为粘着磨损、电弧烧蚀氧化磨损以及磨粒磨损。

肉类多功能检测仪的研制

据调查,一些农贸市场的个别商贩销售掺水肉、病死肉及变质肉等劣质肉品,直接影响消费者的健康。为此,我们经过两年多不断改进与完善,研制出以鉴别肉类掺水肉为主的RJY-Ⅱ型肉类多功能数字检测仪。实际使用证明,该仪器能在数秒钟内准确地检出掺水肉、病死肉及腐败变质肉,填补了我国肉类快速检测技术上的空白。 (一)仪器设计原理、结构、技术指标和稳定性 1.探头和测量电路设计原理。

非洲鸵鸟──21世纪的明星

非洲鸵鸟──２１世纪的明星张丙明（广州军区后勤部军事医学研究所５１０５０７）近年来，鸵鸟养殖业正在世界各地特别是西方一些发达国家蓬勃兴起，群体不断扩大，呈现十分诱人的养殖前景。广东省江门市畜牧局经过数年调查考察和精心策划，于１９９２年１１月首次从美国...

影响胆红素提取率因素探讨

本文探讨了胆红素分层法和钙盐法的提取率及胆汁的新鲜度和不同来源的胆汁对提取率的影响。结果分层法的提取率显著高于钙盐法(P<0.01),新鲜胆汁的提取率显著高于冻存胆汁(P<0.05)。

灭滴灵对犬蠕形螨病的疗效

灭滴灵对犬蠕形螨病的疗效马玉海，张丙明（广州军区后勤部军事医学研究所５１０５０７）笔者于１９９２年６月用灭滴灵对大蠕形螨病作了治疗试验，证明该药安全性好，使用简便，疗效高。（一）材料和方法１．药物：为市售的１０％灭滴灵（Ｍｅｔｒｏｎｉｄ－ａｚｏｌｅ）...

Surface resistivity of carbonaceous fiber/PTFE antistatic coatings

PAN(Polyacrylonitrile)-based carbonaceous fibers were prepared at the heat treatment temperature(HTT)range of 650 to 900 oC.The relationships among HTT,carbon content and volume resistivity of the carbonaceous fibers were investigated.The carbonaceous fibers/PTFE(Polytetrafluoroethylene)antistatic coatings were prepared by the spraying technology and the effects of carbonaceous fibers and pigments on surface resistivity of the coatings were systematically discussed.Micrographs provide insight into the antistatic mechanism of the coating.The results show that carbon content of the carbonaceous fibers increases from 68.8% to 74.8%(mass fraction)and the volume resistivity decreases drastically from 1.94×103 to 8.27×10-2 Ω·cm.The surface resistivity of the antistatic coating is adjustable between 105 and 108 Ω to fit the different antistatic materials.Static is dissipated by a conductive network of short fibers and the tunneling effect between the neighboring fibers and conductive pigments.Conductive pigments make the conductive network more perfect and improve the antistatic ability,but insulating pigments acting as barriers for the formation of conductive channel increases the surface resistivity of the coatings.The influence of pigments on the surface resistivity drops gradually with the decrease of the carbonaceous fibers volume resistivity.

华南军(警)犬血液常规指标测定与分析

九0年以来,我们先后对华南三个军(警)犬训练队的161条军(警)犬的血液常规指标进行测定,结果为血红蛋白含量125g/L,红细胞数6.63×10 12/L,白细胞数10.73×10 9/L。白细胞分类计数:嗜中性63.3%,淋巴28.6%,嗜酸性4.4%,单核3.7%,嗜碱性稀少。据对未成年犬和成年犬血常规指标比较的结果,除红细胞数和白细胞数外,其余指标差异显著。本试验样本数大,所得结果与国内外资料相近,可作为中国军(警)犬血常规指标的背景值,供临床诊疗时参考。