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991.
论述了模块化设计方法及电子专用设备设计的实际特点,并结合模块化设计在电子专用设备研制中的实际应用,阐明了模块化设计的实用性和指导性以及现实意义。 相似文献
992.
To rapidly explore the design space of a real-time embedded system, it is essential to be able to efficiently analyze the timing behaviors of different system architectures. This includes not only determining if a design can satisfy all the timing constraints but also comparing the timing performance of different designs for tradeoff purposes. Understanding the exact timing behavior of a large system can be computationally prohibitive. Previous work in this area has mostly focused on producing a yes/no answer to the schedulability of a system architecture under the worst-case scenario. This not only often leads to overly pessimistic designs, but also provides no insight as how to rank different architectural designs with respect to their timing performance. In this paper, we present several metrics that may be used to measure the timing performance of a design. The metrics were analyzed using workloads from both real-world task systems and randomly generated task systems. A superior metric has been identified through analysis of large sets of experiments. We also show, through an example, how this metric can be used effectively during a design exploration process. 相似文献
993.
Clear effects criterion is an important criterion for selecting fractional factorial designs [1]. Tang et al. [2] derived upper and lower bounds on the maximum number of clear two-factor interactions (2fi's) in 2n-(n-k) designs of resolution Ⅲ and Ⅳ by constructing 2n-(n-k) designs. But the method in [2] does not perform well sometimes when the resolution is III. This article modifies the construction method for 2n-(n-k) designs of resolution Ⅲ in [2]. The modified method is a great improvement on that used in [2]. 相似文献
994.
Tuvi Etzion 《组合设计杂志》2008,16(2):137-151
A doubly constant weight code is a binary code of length n1 + n2, with constant weight w1 + w2, such that the weight of a codeword in the first n1 coordinates is w1. Such codes have applications in obtaining bounds on the sizes of constant weight codes with given minimum distance. Lower and upper bounds on the sizes of such codes are derived. In particular, we show tight connections between optimal codes and some known designs such as Howell designs, Kirkman squares, orthogonal arrays, Steiner systems, and large sets of Steiner systems. These optimal codes are natural generalization of Steiner systems and they are also called doubly Steiner systems. © 2007 Wiley Periodicals, Inc. J Combin Designs 16: 137–151, 2008 相似文献
995.
P.G. Khalatur A.R. Khokhlov S.A. Prokhorova S.S. Sheiko M. Möller P. Reineker D.G. Shirvanyanz N. Starovoitova 《The European physical journal. E, Soft matter》2000,1(1):99-103
Conformational properties of comb-like polymers strongly adsorbed on a flat solid surface were investigated using computer
simulation and scanning force microscopy. The computer simulation showed that the macromolecules with asymmetric distribution
of the side chains relatively to the backbone are effectively in a collapsed state even under conditions of a good solvent.
They formed peculiar helical superstructures which could be observed by scanning force microscopy of cylindrical brushes of
polymethylmethacrylate on mica.
Received 13 September 1999 相似文献
996.
ZENGYun YANMin YANYong-hong FANWei 《半导体光子学与技术》2005,11(1):52-55
A new bipolar junction field-effect transistor (BJFET) was described. The theoretical analysis and computer simulation of BJFET obstructive characteristic are achieved. The gate bias voltage affects the BJFET obstructive voltage greatly. The BJFET obstructive characteristic is relevant to structure parameters of channel width W and channel length L. The decrease-bias-voltage operation can weaken the device obstructive characteristic. The forward turn in device forward obstructive region can also affect the BJFET obstructive characteristic. BJFET has a good high temperature obstructive characteristic and can be applying to high temperature status as high voltage switch devices. 相似文献
997.
参数设计是日本质量专家田口倡导的一种质量工程方法,调节因子的存在性在参数设计中非常重要.在附加了分布假定的条件下,本文对傅珏生等的定理给出了证明,也指出了从函数结构上研究参数设计的重要性. 相似文献
998.
Novel mesoporous hollow‐flower‐ball‐like Cd4Cl3(OH)5 was selectively synthesized using microwave‐irradiation process. The structure of the resultant Cd4Cl3(OH)5 was characterized by scanning electron microscopy (SEM), X‐ray powder diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and low temperature nitrogen sorption isotherms. The concentration of the reagents and the reaction time affect the formation of this hollow‐flower‐ball‐like structure of this complex. The formation of this interesting structure may be attributed to the self‐assembly of smaller inorganic building blocks during the crystallization process of Cd4(OH)5Cl3 crystals. The photocatalytic activity of as‐prepared Cd4(OH)5Cl3 was evaluated by the degradation of salicylic acid and 4‐chlorophenol in water under UV‐irradiation. 相似文献
999.
cdma 2000是面向下一代移动通信设计的宽带无线技术。它采上层、链路层和物理层三层设计,具有较好的灵活性和可伸缩性,可应用于室内外、步行、车载等多种环境。它实现了从现有TIA/EIA95-B系统到下一代移动通信系统的平滑过渡,同时支持系统的信令协议和消息以及与该系统间的切换。 相似文献
1000.
G.P. Pepe G. Peluso R. Scaldaferri L. Parlato C. Granata E. Esposito M. Russo 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,23(4):421-425
A new fabrication process for three-terminal superconducting devices consisting of two Josephson junctions in a stacked configuration
is reported. The process is based on the deposition of the whole Nb/AlxOy/Nb-Al/AlxOy/Nb multilayer on a Si crystalline wafer without any vacuum breaking. Lift-off techniques, anodization processes and a SiO
film deposition have been adopted for patterning and insulating the two tunnel stacked junctions. Devices have been characterized
in terms of current-voltage (I-V) curves and Josephson critical current vs. the externally applied magnetic field. They show high quality factors (V
m values up to 65 mV at 4.2 K), and good current uniformity.
Received 5 June 2001 相似文献