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101.
The ability to utilize fully automated flexible manufacturing systems (FMS) or develop reliable computer-integrated manufacturing (CIM) systems will depend on our ability to develop reliable and reusable software for large complex systems on a timely basis. To date, software design has not gone very far beyond the ad hoc trial-and-error stage. Consequently, the development of software is slow, expensive, unreliable, and unmanageable. The purpose of this paper is to provide a scientific basis for designing software. The approach used here is that of axiomatic design, which is based on two design axioms: the Independence Axiom and the Information Axiom. The axiomatic approach is based on the recognition of the following common elements in design: the existence of independent domains (i.e. the consumer domain, the functional domain, the physical domain, and the process domain); the need to map between various domains during the design process; the decomposition of the characteristic vectors (i.e. functional requirements, design parameters, and process variables) in their respective domains; the zig-zagging required between the domains for decomposition; and the need to satisfy the design axioms during the design process. The axiomatic approach discussed in this paper provides decision making tools for software design in addition to systematic means of knowledge and data representation, synthesis and analysis of software, and the construction of the module-junction structure diagram. 相似文献
102.
103.
新型重整催化剂的研究——Pt/L中沸石酸碱性的作用 总被引:2,自引:0,他引:2
Pt/KL、Pt/BaKL及Pt/HL上的铂与沸石的酸碱位发生相互作用,导致催化剂上存在不同电子状态和粒度分布的铂位,从而产生有着完全不同催化作用、不同抗硫性能的两类催化剂,即以碱性沸石为载体的“单功能”催化剂和以酸性沸石为载体的“双功能”催化剂。在Pt/KL、Pt/BaKL催化剂上,存在着对硫敏感的具有环化脱氢功能和对硫不敏感的仅具有脱氢功能的两类铂活性位。 相似文献
104.
HJ Lee HK Ha MH Kim YK Jeong PN Kim MG Lee JS Kim DJ Suh SG Lee YI Min YH Auh 《Canadian Metallurgical Quarterly》1997,169(2):517-520
OBJECTIVE: The purpose of this study was to evaluate ERCP and CT findings of ectopic drainage of the common bile duct into the duodenal bulb. CONCLUSION: Although rare, the diagnosis of ectopic drainage of the common bile duct into the duodenal bulb is important to prevent inadvertent damage during biliary tract or gastric surgery and to clarify the cause of chronic peptic ulcers. 相似文献
105.
内燃机油添加剂之间相互作用的研究 总被引:3,自引:2,他引:1
探讨了内燃机油添加剂之间的相互作用,磺酸盐与水杨酸盐的相容性差,混合后有沉淀物生产;水杨酸盐与丁二酰亚胺,ZDDP有较弱的相互作用,添加量小时无沉淀物生成,添加量大时才有沉淀物生成;磺酸盐与丁二酰亚胺,ZDDP的相容性好,混合后沉淀物生成。该结论为内燃机油的调配,贮存和全用提供了科学依据。 相似文献
106.
This paper proposes a dynamic Monte Carlo sampling method, called the conditional minimal cut set (COMICS) algorithm, where all arcs are not simulated at each trial and all minimal cut sets need not be given in advance. The proposed algorithm repeats simulating a minimal cut set composed of the arcs which originate from the (new) source node and reducing the network on the basis of the states of simulated arcs until the s-t connectedness is confirmed. We develop the importance sampling estimator, the total hazard estimator and the hazard importance sampling estimator which are all based on the proposed algorithm, and compare the performance of these simulation estimators. It is found that these estimators can significantly reduce the variance of the raw simulation estimator and the usual importance sampling estimator. 相似文献
107.
Microllular plastics are cellular polymers characterized by cell densities greater than 109 cells/cm3 and cells smaller than 10 μm. One of the critical steps in the continuous production of microcellular plastics is the promotion of high cell nucleation rates in a flowing polymer matrix. These high nucleation rates can be achieved by first forming a polymer/gas solution followed by rapidly decreasing the solubility of gas in the polymer. Since, in the processing range of interest, the gas solubility in the polymer decreases as the pressure decreases, a rapid pressure drop element, consisting of a nozzle, has been employed as a continuous microcellular nucleation device. In this paper, the effects of the pressure drop rate on the nucleation of cells and the cell density are discussed. The experimental results indicate that both the magnitude and the cell density are discussed. The experimental results indicate that both the magnitude and the rate of pressure drop play a strong role in microcellular processing. The pressure phenomenon affects the thermodynamic instability induced in the polymer/gas solution and the competition between cell nucleation and growth. 相似文献
108.
Xu You-heng Dong Li-yun Huang Dong-qun Fudan University Shanghai P. R. China 《水动力学研究与进展(B辑)》1998,(3)
In this paper,the oscillation amplitude of the free end of a group of threecylinders are studied.The three cylinders are erected at the vertices of an equilateral trian-gle,and three arrangements are made in this study.One of the three cylinders is served asa working cylinder which is mounted by a flexible cantilever and two accelerometers areattached on the free end in two directions.The results of the three-cylinder arrangementare compared with those of two cylinders in tandem/side-by-side arrangement in the samecondition.The experimental results show that the rear cylinder of a group of three cylin-ders is affected more seriously than that of the corresponding two cylinders in the contrastarrangement.The main direction of oscillation is changed.The transversal oscillation isstronger than the longitudinal oscillation in the three-cylinder arrangement.On the con-trary,the transversal oscillation is much weaker than the longitudinal oscillation in two-cylinder arrangement.The largest transversal oscillat 相似文献
109.
1MotivationsIncreasingdensityofVLSIchipsmakesthecostoftestingveryexpensive.Designfortestabilitycantemperthisproblemdrastically.Therearetwokindsofsolutions:(i)localsolutionl3'2]withlowcomputingcomplexity,whichcannotalwaysgetsatisfactoryresults;(ii)globa.lsolutionwithprohibitivecomputingcomplekityl1'5].T.H.Chen'andM.A.Breuer[1lpresentedanILPmodeltoplacetestpointsglobally.Becauseofitscomputingcomplealty,[1lcanonlydealwithsmallormediumscalecircuits.SCOAPisusedin[1],whichisnotaveryaccuratet… 相似文献
110.