共查询到20条相似文献,搜索用时 78 毫秒
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清洗印制电路板的传统方法是用有机溶剂清洗,由CFC-113与少量乙醇(或异丙醇)组成的混合有机溶剂对松香助焊剂的残留物有很好的清洗能力,这种有机溶剂对极性污垢和非极性污垢都有很好的溶解能力,但由于CFC-113对大气臭氧层有破坏作用,目前已被禁止使用,目前可选用 相似文献
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之己 《大气与环境光学学报》1997,(1)
地表主要污染源之一为石油产品的存贮及配送设施。汽油、柴油、煤油及飞机燃料等均存贮在地面或地下油罐中,全世界这类油罐数以百万计而且大多数都使用了数十年,有可能产生泄漏。这种泄漏常常是缓慢的,大多数常规手段无法立即探查到。例如地面油罐的液面测量就没有效果,因为缓慢泄漏造成的变化与整个油罐容积相比微不足道,难以察觉。但是长期缓慢泄漏污染了地下及油罐周围的土壤,甚至使土壤饱和并污染了地下水。许多地区都已报道过大型油罐场下面的地下水面漂浮着数英尺的石油产品。以往检测水中的碳氢化合物是在现场或实验室对采样进… 相似文献
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土壤被石油污染之后,使得地里的植物不容易生长的很好,在他们之间存在食物的关系,这就会让人类的身体状况受到影响,所以,我们要实施有用的方法去进行治理。目前,根据研究数据统计,通过超声处理的办法来加强石油的污染物把土壤表面的污染物解决吸收,在超声的功率越来越强下,使得黏土的颗粒所吸附的稠油的数量就会减少,尤其是超声空化的作用,能够把土壤中所残存的油族等组分给去掉,其结果很是显著。 相似文献
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友清 《激光与光电子学进展》1995,32(11):31-32
用染料激光系统探测土壤污染一种用於现场探测土壤和地下水中石油碳氢化合物的快速筛选仪器(ROST)系统(以染料激光为基础的仪器),将可消除钻孔和取样的麻烦,用这种仪器可以通过激光感生荧光法就地探测石油碳氢化合物的污染。在普通取样法中,一般要化几千美元钻... 相似文献
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为了更有效的提高储量和产量,同时降低成本,大型石油公司纷纷开始建设数字石油矿区。数字石油矿区对可持续发展有重要的意义,可以最大化地优化资源配置和产业结构,但是当前的数字石油矿区设计,指导性不强,还有很大的缺陷。本文从当前数字石油现状出发,将办公自动化技术和当前流行的虚拟现实技术引入数字石油矿区的设计之中,提出了一种新的数字石油设计的构想。 相似文献
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《大气与环境光学学报》2000,(2)
石油和燃料维持世界正常运转,但它们也严重地污染了土壤和水。激光诱导荧光光谱已成为探测这些污染的可靠工具,尤其对土壤层的现场监测。现在Erlangen-Nurnberg大学的研究人员通过引入一个相对简单且有效的定标方法改进了这个过程。来自于亮沙土的背向散射光比来自暗泥土的要强得多,这一直是使用激光诱导荧光进行现场监测的一个颇为重要的问题,因为它使荧光信号产生颇大的改变。一些科学家对这些进行了研究,通过把漫反射率光谱组合进这项技术,研究人员能够弥补不同类型土壤引起的变化,从而简化了定标。激光诱导荧光… 相似文献
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Michael Reilly 《半导体技术》2004,29(12)
DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system. 相似文献
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Thomas M.Trexler 《半导体技术》2004,29(5)
From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test. 相似文献
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The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation. 相似文献
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The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high. 相似文献
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Today, micro-system technology and the development of new MEMS (Micro-Electro-Mechanical Systems) are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible. 相似文献
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Qi-jiang Ran Pei-de Han Yu-jun Quan Li-peng Gao Fan-ping Zeng Chun-hua Zhao 《光电子快报》2008,4(4):239-242
This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel's. 相似文献
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Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers
A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it. 相似文献
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A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working. 相似文献
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It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output(MIMO) communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory. 相似文献
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《中国通信》2014,(7)
正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks 相似文献