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21.
步进式加热炉炉温优化设定模型及软件开发 总被引:1,自引:0,他引:1
针对线材厂步进式加热炉实际工况,提出了基于经验规则的炉温优化设定模型和在线自学习获取知识的思想,并以炉温优化设定模型为核心,开发出加热炉计算机控制系统的优化运行软件。 相似文献
22.
讲述了参观Semicon/west94′展览会及考察美国和西德的5个公司、1所大学所了解到的投影光刻技术、电子束曝光技术、透镜面形测试技术的发展。 相似文献
23.
An approach to solving a linear interpolation problem in a fuzzy information space is proposed. Two different schemes of interpolation
are outlined: a heuristic one, based on the geometrical interpretation of operations, and an optimization one, based on the
expansion principle. The results obtained allow performing fuzzy linear prediction.
__________
Translated from Kibernetika i Sistemnyi Analiz, No. 2, pp. 55–68, March–April 2006. 相似文献
24.
F. D. McDaniel B. L. Doyle C. H. Seager D. S. Walsh G. Vizkelethy D. K. Brice C. Yang P. Rossi M. Nigam M. El Bouanani G. V. Ravi Prasad J. C. Schwartz L. T. Mitchell J. L. Duggan 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2002,190(1-4):1-10
A new ion beam analysis-based, single ion technique called the time to first photon has been developed to measure the decay of the luminescence signal of phosphors. Such measurements are currently needed to study luminescence decay mechanisms following high-density excitations and to identify strongly luminescent phosphor coatings with short lifetimes for ion photon emission microscopy (IPEM). The samples for this technique consist of thin phosphor layers placed or coated on the surface of PIN diodes. Single ions from an accelerator strike this sample and simultaneously create ion beam induced luminescence (IBIL) from the phosphor that is measured by a single-photon-detector, and an ion beam induced charge collection (IBICC) signal in the PIN diode. In this case, the IBICC signal provides the start pulse and the IBIL signal the stop pulse to a time to amplitude converter. It is straightforward to show that this approach also measures a signal proportional to activity versus time with an accuracy of 5% as long as the number of detected photons per ion is less than 0.1, which usually requires the use of absorbers for the IBIL detector or electronic discrimination for the IBIL signals. Details of the new analysis are given together with examples of luminescence decay measurements of several ceramic phosphors being considered to coat IPEM samples. IPEM is currently being developed at Sandia National Laboratory (SNL), the University of North Texas in Denton, and the Universities and INFN of Padova and Torino. 相似文献
25.
磁偏转电子枪研制核靶 总被引:3,自引:3,他引:0
文章叙述了磁偏转电子枪的原理和结构以及用EQD-3型电子枪研制各种核靶的工艺过程。 相似文献
26.
本文提出光束轨迹方程的一般解,导出解析解的存在条件,推广了文献[1]的光线传播理论,文中以一特定梯度折射率棒为例,讨论了高斯光束在棒中的传播特性。 相似文献
27.
甄汉生 《真空科学与技术学报》1993,(2)
微波电子回旋共振等离子体是淀积薄膜、微细加工和材料表面改性的一种重要手段。由于这种等离子体电离水平高,化学活性好,可以用来实现基片上薄膜的室温化学气相淀积和反应离子刻蚀,因此对于微电子学、光电子学和薄膜传感器件的发展,这种等离子体会具有重要的意义。此外,采用微波电子回旋共振等离子体原理,没有灯丝的离子源可以提高离子源的使用寿命,可以增加离子束的束流密度。可以确信,微波电子回旋共振等离子体的发展,将把离子源技术提高到一个新的水平。显然,这必将对材料表面改性工艺,包括离子注入掺杂等工艺的发展发挥作用。自从1985年以来,为了得到大容积等离子体而发展了微波电子回旋共振多磁极等离子体,这些技术在薄膜技术、微细加工以及材料表面改性中的应用前景是乐观的。我们将在本文中,介绍微波电子回旋共振等离子体的原理及其应用。 相似文献
28.
We have utilized a variable energy positron beam and infrared transmission spectroscopy to study defects in GaAs epilayers
grown at low temperatures (LT-GaAs) by molecular beam epitaxy. We have measured the Doppler broadening of the positron-electron
annihilation gamma ray spectra as a function of positron implantation energy. From these measurements, we have obtained results
for the depth profiles of Ga monovacancies in unannealed LT-GaAs and Ga monovacancies and arsenic cluster related defects
in annealed LT-GaAs. We have also studied the effects of the Si impurities in annealed LT-GaAs. The infrared transmission
measurements on unannealed LT-GaAs furnish a broad defect band, related to As antisites, centered at 0.370 eV below the conduction
band. 相似文献
29.
New accurate two-noded shear-flexible curved beam elements 总被引:2,自引:0,他引:2
There are two purposes of this work. One is to present two accurate two-noded finite elements which are derived from the
potential energy principle and the Hellinger–Reissner functional principle respectively. The second is to show the successful
application of the internal displacement parameters in developing a high-order related displacement-rotation interpolation
field. Because the derived interpolation field is capable of accurately modeling deformation modes in extreme thin curved
beams and nearly straight beams, both shear locking and membrane shocking are avoided. Several standard numerical tests display
superior behaviors of the present elements.
Received: 5 February 2002 / Accepted: 16 September 2002 相似文献
30.
Detection of multiple cracks using frequency measurements 总被引:2,自引:0,他引:2
D.P. Patil 《Engineering Fracture Mechanics》2003,70(12):1553-1572
A method for detection of multiple open cracks in a slender Euler-Bernoulli beams is presented based on frequency measurements. The method is based on the approach given by Hu and Liang [J. Franklin Inst. 330 (5) (1993) 841], transverse vibration modelling through transfer matrix method and representation of a crack by rotational spring. The beam is virtually divided into a number of segments, which can be decided by the analyst, and each of them is considered to be associated with a damage parameter. The procedure gives a linear relationship explicitly between the changes in natural frequencies of the beam and the damage parameters. These parameters are determined from the knowledge of changes in the natural frequencies. After obtaining them, each is treated in turn to exactly pinpoint the crack location in the segment and determine its size. The forward, or natural frequency determination, problems are examined in the passing. The method is approximate, but it can handle segmented beams, any boundary conditions, intermediate spring or rigid supports, etc. It eliminates the need for any symbolic computation which is envisaged by Hu and Liang [J. Franklin Inst. 330 (5) (1993) 841] to obtain mode shapes of the corresponding uncracked beams. The proposed method gives a clear insight into the whole analysis. Case studies (numerical) are presented to demonstrate the method effectiveness for two simultaneous cracks of size 10% and more of section depth. The differences between the actual and predicted crack locations and sizes are less than 10% and 15% respectively. The numbers of segments into which the beam is virtually divided limits the maximum number of cracks that can be handled. The difference in the forward problem is less than 5%. 相似文献