共查询到20条相似文献,搜索用时 62 毫秒
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《航空精密制造技术》2009,45(4)
JM:在制造业飞速发展的带动下,中国工具工业也取得了跨越式的发展,请您介绍一下我国工具工业最近几年的发展情况? 沈秘书长:自上世纪90年代我国经济进入市场化改革以来,以国有企业为主体的机床工具企业为了适应市场经济的需要,进行了前所未有的大规模改制和调整. 相似文献
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国际金融危机及其引发的全球经济衰退,使工具工业经受了严重的冲击。随着中国经济的回升和经济结构的调整,现代制造业发展的速度正在加快。由于制造业的加工技术水平受刀具行业整体水平的影响较大,制造业的发展会促进刀具行业的发展,从而为工具企业提供了一个良好的市场机遇。在新的发展形势下,工具行业需要打破资源浪费、低水平扩张、粗放式经营的现状,实施产业结构调整。面对日益增多的难加工材料,根据制造业发展的需要,刀具行业必须改进刀具材料、研发新的刀具材料和更合理的刀具结构。 相似文献
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周梁珠 《航空精密制造技术》1985,(3)
大尺寸平行度检具解决问题我所在研制“海豚”桨毂50吨热压机时,其床身四根相距1500毫米左右的导轨要求相互平行(平行度在0.01毫米内),我们在装配中自制了简单的测量工具,解决了装配中的测量和调整问题。此工具仅有几个零件,结构简单, 相似文献
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彭峰平 《航空精密制造技术》2009,45(5)
贵州西南工具(集团)有限公司是中航工业集团公司所属以机床、工量具和精密零部件为主产品的专业化企业,是在国家对军工企业实施结构性调整和改革脱困的背景下,由贵航集团公司收购西南工具总厂破产有效资产重新组建的一家股份制公司,成立于2003年. 相似文献
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介绍了在万能工具铣床上加工复杂斜面的方法和步骤,以及在合理装夹零件的情况下,依据复杂斜面的有关向量,计算工作台调整角度的向量计算法。 相似文献
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方次尹 《航空精密制造技术》1990,(4)
机器零件抛光去毛刺用的尼龙纤维刷类等工具,分散着SiC、Al_2O_3等磨料。这类工具多用圆形纤维制成。去毛刺时,利用纤维端部来回拨动,使毛刺破断。它的缺点是加工过程纤维损伤以后,使工具的中心点偏移。在人工去毛刺条件下,完全由人的经验调整。美国 相似文献
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从科技论文的特点看科技论文的选题 总被引:3,自引:0,他引:3
姜艳秋 《沈阳航空工业学院学报》1999,16(2):87-90
本文论述了科技文的特点及选师原则。在特点方面主要就科技论文的科学性,创造性,理论性进行了阐述,在选题方面科技论文选题的客观需要与主条件进行阐述,旨在揭示科技论文的特点与课题选择之间的关系,从而了解其特点,并据此选题,写出符合要求的科技论文。 相似文献
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简介了任务计算机调试设备配套软件在任务计算机仿真环境中的重要作用 ,对该软件设计方法和流程进行了详细的说明 ,主要介绍了VC ++6 .0环境下串行通信和显示控制软件的设计技术 ,并讨论了如何提高应用程序性能的途径。 相似文献
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J. Martin Laming 《Space Science Reviews》1994,70(1-2):107-110
The ultraviolet spectrum of a redshifted plasma flow appearing over a sunspot observed during the first flight of the High Resolution Telescope Spectrograph (HRTS I) is analysed, and interpreted as a radiatively cooling plasma. For most of the lines emitted from this plasma, the assumption of ionization equilibrium during the cooling is good. However for He II (and other ions with a single electron outside of closed shells), this is not the case. Integrating differential equations for the various ionization fractions of helium and the temperature allows an approximate determination of the abundance of helium relative to other elements whose lines appear in the spectrum of the plasma flow. 相似文献
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《中国航空学报》2017,(6)
We conducted experiments in a wind tunnel with Mach number 2 to explore the evolution of a transverse plasma jet and its modification effect on a shock wave induced by a ramp with an angle of 24°. The transverse plasma jet was created by arc discharge in a small cylindrical cavity with a 2 mm diameter orifice. Three group tests with different actuator arrangements in the spanwise or streamwise direction upstream from the ramp were respectively studied to compare their disturbances to the shock wave. As shown by a time-resolved schlieren system, an unsteady motion of the shock wave by actuation was found: the shock wave was significantly modified by the plasma jet with an upstream motion and a reduced angle. Compared to spanwise actuation, a more intensive impact was obtained with two or three streamwise actuators working together. From shock wave structures, the control effect of the plasma jet on the shock motion based on a thermal effect, a potential cause of shock modification, was discussed. Furthermore, we performed a numerical simulation by using the Improved Delayed Detached Eddy Simulation(IDDES) method to simulate the evolution of the transverse plasma jet plume produced by two streamwise actuators. The results show that flow structures are similar to those identified in schlieren images. Two streamwise vortices were recognized, which indicates that the higher jet plume is the result of the overlap of two streamwise jets. 相似文献
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Impulse action of a cavitation bubble on a rigid wall is studied depending on the distance between them. We determine the distances at which the periphery pressure maximums on a wall are preserved as well as the distances at which these maximums exceed the water hammer pressure. 相似文献
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R. F. Mardanov 《Russian Aeronautics (Iz VUZ)》2011,54(3):308-313
We suggest a method to solve one of the model problems of aerohydrodynamics, namely, a problem of a flow about a point source,
from which a fluid with density and total pressure, different from the corresponding values in the incoming flow enters. The
calculations are carried out for various values of the determining parameter; and the data are compared with the known results.
We revealed the advantages of the suggested method in comparison with the known ones. 相似文献
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The natural damped frequencies of a viscous liquid in a circular cylindrical container are obtained for slipping and anchored contact line at the container wall r = a. In addition the response to translational forced excitation has been determined. The results may also be applied to viscous liquid in a micro-gravity environment, as long as the contact angle of the liquid surface to the cylindrical container wall is in the vicinity of π/2, indicating, that the free liquid surface equilibrium position remains a plane surface. It could be found that there exists in contrast to frictionless liquid a small filling range, in which the liquid performs only an aperiodic motion. The adherence condition at the side wall was replaced by the somewhat weaker condition of an anchored contact line. 相似文献
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The progress of seakeeping computations requires development of computating codes for unsteady flows around a ship or its elements. In this paper, we present a method of calculation concerning waves radiated by an oscillating surface-piercing flat plate with forward speed, with a yaw angle. By use of Green's third identity, the problem is transformed into the resolution of a Fredholm integral equation of the first kind by a panel method using Green's function. The Green's diffraction-radiation function with forward speed is used. Its numerical values are calculated by an adaptative integration procedure to reduce the computation time. The present method permits determination of the pressure jump distribution across the plate, the total forces and moments. The results obtained are compared with other numerical methods in hydrodynamics and in aerodynamics, and with experimental data obtained in a water tank. 相似文献
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Tadas K. Nakamura 《Space Science Reviews》2006,122(1-4):271-278
The problem of energy-momentum in a body with a finite volume has been causing confusion in the theory of relativity, especially
in relativistic thermodynamics. Its correct understanding has been given since the early years of relativity, however, erroneous
misunderstandings are still found in papers and textbooks to this date. The present paper introduces a simple paradox to demonstrate
the problem, and gives a brief review on a way to handle the energy-momentum correctly. 相似文献
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The intersections of a loxodrome (rhumb line) and a great circle are of interest for some navigational problems, but a closed-form solution cannot be formulated. An algorithm is given for computing approximations to any desired degree of accuracy using Newton's method. By using the equatorial angle φ as an independent variable all solutions can be found rapidly using the modest computational capabilities of a personal computer 相似文献