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101.
运用开关信号理论和有界算术运算理论,对电流镜的多种性质进行了讨论,并系统研究了利用电流镜实现电流信号的各种算术运算,其中倍除运算属于初次提出,最后通过N进制半加电路和N值比较电路等两个设计实例介绍了电流镜技术在I^2L电路开关级设计中的应用。 相似文献
102.
A rectangular cartogram is a type of map where every region is a rectangle. The size of the rectangles is chosen such that their areas represent a geographic variable (e.g., population). Good rectangular cartograms are hard to generate: The area specifications for each rectangle may make it impossible to realize correct adjacencies between the regions and so hamper the intuitive understanding of the map.
We present the first algorithms for rectangular cartogram construction. Our algorithms depend on a precise formalization of region adjacencies and build upon existing VLSI layout algorithms. Furthermore, we characterize a non-trivial class of rectangular subdivisions for which exact cartograms can be computed efficiently. An implementation of our algorithms and various tests show that in practice, visually pleasing rectangular cartograms with small cartographic error can be generated effectively. 相似文献
103.
本文描述了在一台国产0.6m环形抛光机上磨制Φ80×10mm、φ150×12mm、φ220×28mm三块K9材料平面镜及一块φ120×15mm微晶料平面镜的实验过程,从工艺角度归纳出了若干磨制规律。 相似文献
104.
Hoseong Kim Jaeho Choi Kook-Nyung Lee Yong-Kweon Kim Eun-mi Kim Byung-Gee Kim 《Optics and Lasers in Engineering》2006,44(11):1198-1208
A novel optical arrangement for fluorescence detection that employs spatial separation as well as spectral filter to increase the signal to noise ratio is proposed. Using a prism and two mirrors, the elliptical laser beam of a laser diode, as an excitation light, is homogenized and the transmitted excitation light is separated from the fluorescence not to reach the collecting optics. Uncooled CCD can capture the fluorescence image of up to 40 fluorescently-labeled protein patterns without scanning or mechanical translation. This paper presents the simulation, construction and measurement results of the developed optical system. The measurements show that the combination of prism and mirrors converts the excitation light from the laser diode to uniform illumination on the specimen, and provides the separation between excitation and fluorescence light to give high signal to noise ratio. It is also possible to assay various protein concentrations ranging from 1000 to 10 ng/ml reliably. We believe that the proposed fluorescence detection system can be used to build a commercially valuable, low cost, hand-held or miniature fast detection device for point-of-care applications. 相似文献
105.
通过对非线性镜锁模激光器的稳态分析,找到了它的锁模条件及锁模脉冲的强度极限,为该激光器输出高功率的短脉冲提供了理论依据。 相似文献
106.
Fracture of a rectangular piezoelectromagnetic body 总被引:5,自引:0,他引:5
The singular stress, electric fields and magnetic fields in a rectangular piezoelectromagnetic body containing a center Griffith crack under longitudinal shear are obtained. Fourier transforms and Fourier sine series are used to reduce the mixed boundary value problems of the crack, which is assumed to be impermeable, to dual integral equations. The solution of the dual integral equations is then expressed in terms of Fredholm integral equations of the second kind. Expressions for stresses, electric displacements and magnetic inductions in the vicinity of the crack tip are derived. Also obtained are the field intensity factors and the energy release rates. Numerical results obtained show that the geometry of the rectangular body have significant influence on the field intensity factors and the energy release rates. 相似文献
107.
An analytical solution is obtained for the linearized problem of the behavior of a collisional gas plasma in a half-space in an external alternating electric field. It is assumed that the electrons are mirror-reflected from the plasma boundary. The solution is used for finding the screened field. The case of an external field frequency close to the plasma frequency is investigated separately. 相似文献
108.
采用水热法结合银镜反应制备出一系列不同Ag负载量(2.2%、4.0%、6.4%,w/w)改性的3D纳米网状结构Ag@Ti O2薄膜电极。利用电感耦合等离子体技术(ICP)、X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)和X射线能谱(EDX)等表征手段测试所合成材料的形貌及成分,实验结果表明Ag纳米颗粒可以成功沉积在Ti O2纳米线表面。电化学测试数据则表明,4.0%(w/w)负载量的Ag@Ti O2相比于未改性和其他负载量的Ti O2纳米线具有更好的倍率性能和更稳定的可逆容量。在50,100,200,400,800和1 200 m A·g~(-1)的电流密度条件下,该改性电极的放电容量可分别达到261.4,253.7,239.5,216.5,193.1和185.1 m Ah·g~(-1),在200 m A·g~(-1)下循环80次后容量保持率仍能达到99.8%。 相似文献
109.
光学读出式红外成像技术是近年来研究的热点,本文讨论了镜面弯曲对光学检测灵敏度的影响。由双材料微悬臂梁组成的非致冷焦平面阵列通过体刻蚀工艺加工而成,由于残余应力的影响,制成的焦平面阵列将会发生弯曲,应力导致的镜面弯曲将会降低光学探测灵敏度。本文通过傅立叶光学模拟了镜面弯曲对光学探测灵敏度的影响,并通过实验验证了该模型。实验和模拟结果表明,在镜面曲率为0 .1mm-1时,光学探测灵敏度将会降低到理想情况的40 %。最后我们用这个模型评价了通过表面修饰来提高光学性能的效果。 相似文献
110.