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张景奇 《精密制造与自动化》1989,(4):16-22
一、简介参加本届中国国际机床展览会制造三坐标测量机和测量系统的公司约有十三家,其中美国四家:Sheffield公司、Cincinnalti公司、Starrett公司和Moore公司等;英国三家;Ferrenti公司、Keeling Metrology(Kemeo)公司和Eley Warren公司等;西德三家:Wild- 相似文献
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数控机床配置的数控系统品牌繁多,性能和结构也不尽相同。德国SIEMENS公司和日本FANUC公司是世界上主要的数控系统生产厂商,此外.国外厂商还有法国NUM公司、德国HEIDENHAIN公司、日本MITSUBISHI公司、西班牙FAGOR公司等。近年来,随着数控机床在我国迅速发展. 相似文献
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数控机床配置的数控系统品牌繁多,性能和结构也不尽相同。德国SIEMENS公司和日本FANUC公司是世界上主要的数控系统生产厂商,此外.国外厂商还有法国NUM公司、德国HEIDENHAIN公司、日本MITSUBISHI公司、西班牙FAGOR公司等。近年来,随着数控机床在我国迅速发展. 相似文献
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公司称称美国PAEXUS公司美国哈挺公司瑞士FRIBOSA公司美国EXTRUDE HONE公司西德HERTEL公司日本牧野公司美国BROWN七SHAFPE公司日本牧野公司瑞士CHARMILLES公司日本东京贸易公司日本铃木公司日本东源机械公司日本ASHINO公司日本牧野公司瑞士COSA公司日本1515公司日本JAPAX日本三菱公司日本SODICK公司西德COSA公司美国LAMKO美国MOORE公司机械计算机辅助设计系统带数显公/英制工具车床数字式转台,高度仪、显示器挤压研磨机T7C万能撞头数控仿型铣床FDNC128一A沁平面磨床肚8数控电火花机床及附件线切割机… 相似文献
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尤秀珍 《精密制造与自动化》1989,(4):54-57
GMN公司是西德的轴承制造公司,也是世界著名的生产磨头的公司,该公司生产的高频电主轴更为著名,是世界先进水平的少数几个厂家之一,为了深入了解GMN公司磨头的技术水平,把收集到的专有技术资料进行了整理,发现GMN公司从七十年代到八十年代初共申请 相似文献
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《流体机械》2013,(11)
通过对自然工质R290蒸气珠状凝结传热过程的微尺度特性分析得出,在一定的过冷度、液珠半径和分形维数下,液珠的导热热阻随接触角的增大而增大,促进层的热阻在接触角为90°时最小,气液界面的热阻随着接触角的增大而减小,单个液珠的总传热热阻随着接触角的增大呈现出先减小后增大的变化规律,即存在最佳接触角,在此最佳接触角下,单个液珠的总传热热阻最小,单个液珠的传热量最大,换热表面的热流密度最高。随着液珠半径的增大,最佳接触角减小。随着过冷度的增加和分形维数的增大,换热表面液珠成核中心密度增大,表面的热流密度增加。在一定的过冷度下,液珠半径增大,液珠分布密度减少,分形维数增大,液珠的分布密度增加。在一定的分形维数和过冷度下,随着液珠半径的减小,换热表面的热流密度增大。 相似文献
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Suo T Peng P Feng M Liu H Ai Z Tong S Yang X Qin X 《Microscopy research and technique》2012,75(3):294-299
By investigating the identities, amounts, and distributions of the major components of human gallstones, the formation mechanism of calculi may be elucidated. Using FT-IR specular reflection spectroscopy, the compositions of five common types of gallstones, including cholesterol calculus, bile pigment calculus, cholesterol-bilirubin calculus, mixed calculus, and black stones, were positionally, qualitatively, and quantitatively analyzed. Several organic and inorganic substances were found in human gallstones, including cholesterol, calcium bilirubinate, calcium carbonate, calcium phosphate, and calcium stearate. Among them, cholesterol and calcium bilirubinate were the main components. The amounts of these substances varied in different types of gallstone. The distributions of cholesterol and calcium salts (with the exception of calcium bilirubinate) were also closely associated with location. In the various calculi, the amounts of cholesterol and calcium bilirubinate in the cores, the layered structures outside the cores, and the outer shells were higher than those of other substances. The identities of the major components of calculi were similar in different types of gallstones, but their amounts and distributions were significantly different. The analytical method used in this study, which was able to accurately determine the location, quality, and quantity of the major components of gallstones, would be an effective tool to study the formation mechanism of calculi. 相似文献
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Cadmium, zinc, selenium, and copper were administered, singly or in combination, orally or subcutaneously. Experiment I included 32 calves of both sexes; six received Cd (two groups), Zn, Cd, and Zn, and Cd and Se (two groups) and one group was a control. In Experiment II (21 bulls), three were given Cd, Cd, and Cu, and Cd and Zn, respectively, and one group was a control. For light microscopy, in Experiment I the highest amounts of silver granules were present in the samples of liver, small intestine, and vesicular gland of all the exposed groups; in Experiment II the most affected organs were liver, kidney, and small intestine. For electron microscopy, in Experiment I, after administration of Cd and Zn, the highest amounts of granules were seen in the cytoplasm of hepatocytes and cells of the proximal and distal renal tubules and the lowest amounts were found in glandular cells of the pancreas. Administration of Cd and Se resulted in the presence of large numbers of granules in the nuclei and nucleoli of spermatogonies. In Experiment II, ingestion of Cd and Zn in feed led to the appearance of highest amounts of granules in the nucleoli, nuclei, and cytoplasm of cells in testes, kidneys, and pancreas. Following Cd intake, the highest accumulation of granules was observed in the nucleoli of hepatocytes and cells of the proximal and distal renal tubules. Combined Cd and Cu produced the highest number of granules in cells of the proximal and distal renal tubules and in the nucleoli and nuclei of germinal epithelium. 相似文献
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热管废热回收蒸发器在浊水余热回收中的应用 总被引:1,自引:1,他引:0
针对污水的特性,为避免生活污水与热泵工质R22产生交叉污染,从而导致系统不能正常运行的可能性,提出在污水与热泵系统工质R22之间采用一个热管换热器,得出在系统增加了一个热管换热器的情况下,污水流量一定时,热泵制热量,性能系数COP值,热泵系统R22工质蒸发温度,污水废热回收热量随污水进口温度的增大而增大,其中热泵工质蒸发温度的增幅最大,达到65.79%,废热回收热量的增幅最小,为6.8%,污水入口温度一定时,热泵制热量,性能系数COP值,热泵工质蒸发温度,废水回收热量随着污水流量的升高而升高,但是热泵工质蒸发温度的和性能系数COP值的增幅减少,热泵制热量,热管工质蒸发温度以及废水回收热量的增幅缓慢增加. 相似文献
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Wang Xiankui 《Frontiers of Mechanical Engineering in China》2007,2(3):251-262
Advanced manufacturing consists of continuity of manufacturing, its broad sense, and the core of the manufacturing process.
The technology of continuous manufacturing is discussed according to both historical and modern perspectives. The relationship
between human development and manufacturing technology is also discussed. Manufacturing is a continuously evolving topic.
It is not only the foundation and means of imagination, conception, the science, and the technology of material change, but
also the expression of national economy, national defense, and the support industries. The broad sense of manufacturing theory,
which extends the concept of manufacturing, is an important development in the 20th century. The sense is analyzed in connection
with design, material forming theory, synthesis of manufacturing technology, manufacturing modes, life cycle of product, hardware
and software, and support environment, etc. At the same time, the core action and the development of the theory and technology
of process is also discussed. At the end of this paper, the development directions of mechanical manufacturing science and
technology are mentioned. 相似文献
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随着科技的发展和进步,石油、天然气和页岩气等能源已成为全球所有国家的命脉。然而想要拥有足够的能源,就必须具备先进的开采技术,因此钻井泵的发展尤为重要。钻井泵被誉为钻机的“心脏”,对于钻机来说至关重要,而对于钻井泵来说其液力端易损件的使用寿命与钻井泵的工作效率和使用寿命息息相关,因此只有提高钻井泵液力端易损件的使用寿命才能确保钻井泵的正常钻进、较高的工作效率和使用寿命。随着信息技术的发展和各行各业的相互促进与相互影响,在未来钻井泵也会向着信息化、自动化、轻量化、人性化和智能化的方向发展。 相似文献
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以Delta机器人为分析对象,研究了动平台的位置误差模型,并对误差源的耦合特性进行了分析。首先,利用从动臂的位置特性,依据几何空间矢量法,建立了Delta机器人机构误差模型;其次,以数理统计与空间矢量原理为基础,推导出Delta机器人关节间隙误差模型;然后,基于空间有限元理论,在建立系统弹性动力学模型的基础上建立了其柔性误差模型;综合考虑这3种误差源,建立了Delta机器人综合位置误差模型;最后,利用Adams与Workbench联合仿真、Matlab数值计算和FARO激光跟踪仪的现场试验验证了位置误差模型的正确性,并对误差源的耦合特性进行了分析,阐述了方向位置误差与坐标轴方位之间的关系。结果表明,影响Delta机器人动平台位置误差的各个误差源间并不是简单的叠加,而是具有明显的耦合特性,并且动平台方向位置误差会随着坐标轴方位的变化而变化。 相似文献
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针对传统固体反射面机构主反射面型面精度和收拢率较低的问题,设计了一种可展开固体反射面机构。首先,提出4种固体反射面机构可展单元构型并对其机构自由度进行分析,对比分析构型方案优缺点确定构型方案4作为可展单元基础构型,并对其结构和展开原理进行详细设计。通过D-H坐标变换建立该机构可展单元的运动学模型,根据几何约束条件建立机构位置矢量方程,利用向量封闭投影法解出各回转角间的关系,结合MATLAB软件编程对机构的位置、速度和加速度进行分析。应用ADAMS软件建立机构仿真模型,验证了机构运动学分析的正确性。最后根据机构中回转角的限制条件和结构尺寸关系,分析回转角和结构尺寸对可展开固体反射面机构收拢率的影响,确定2.2m可展开固体反射面机构的回转角和旋转角分别为78°和30°,中心圆盘半径、铰支座一孔纵向尺寸、切换连杆横向尺寸、纵向尺寸分别为245,8,40,18mm,收拢率为0.326,从而为可展开固体反射面机构的设计提供参考。 相似文献