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排序方式: 共有1731条查询结果,搜索用时 9 毫秒
61.
JP Dubey KR Dorough MC Jenkins S Liddell CA Speer OC Kwok SK Shen 《Canadian Metallurgical Quarterly》1998,28(8):1293-1304
Clinical signs, diagnosis, treatment and isolation of Neospora caninum from two littermate dogs are described. Three of six pups from a Labrador bitch developed paralysis. Neosporosis was diagnosed ante mortem by serological examination in two of the affected pups. At necropsy, tissue cysts were seen in unstained smears and in histologic sections of their brains. Tissue cysts were often thin-walled (approximately 1 micron) but antigenically and ultrastructurally identified as N. caninum. Furthermore, N. caninum (isolates NC-4, NC-5) was isolated in mice and in cell cultures inoculated with neural tissues of these two dogs. Serological diagnosis of neosporosis using a variety of tests is discussed. 相似文献
62.
63.
In this paper, a cost analysis of recovery block scheme has been presented. This study provides us the selection criterion for alternates and the software granularity under perfect acceptance tests. Two performance evaluation measures: a) cost-reliability index (CRI); b) cost of failure (COF) are studied and compared. CRI is shown to be a move restricted measure than COF. An experimental study has been carried out to supplement the analysis. Efficient placement of recovery blocks and the design of alternates has been discussed with reference to real-time applications.This work has been carried out under contract DOT-RC-92031. 相似文献
64.
Nanomechanical characterization of multilayered thin film structures for digital micromirror devices
The digital micromirror device (DMD), used for digital projection displays, comprises a surface-micromachined array of up to 2.07 million aluminum micromirrors (14 μm square and 15 μm pitch), which switch forward and backward thousands of times per second using electrostatic attraction. The nanomechanical properties of the thin-film structures used are important to the performance of the DMD. In this paper, the nanomechanical characterization of the single and multilayered thin film structures, which are of interest in DMDs, is carried out. The hardness, Young's modulus and scratch resistance of TiN/Si, SiO2/Si, Al alloy/Si, TiN/Al alloy/Si and SiO2/TiN/Al alloy/Si thin-film structures were measured using nanoindentation and nanoscratch techniques, respectively. The residual (internal) stresses developed during the thin film growth were estimated by measuring the radius of curvature of the sample before and after deposition. To better understand the nanomechanical properties of these thin film materials, the surface and interface analysis of the samples were conducted using X-ray photoelectron spectroscopy. The nanomechanical properties of these materials are analyzed and the impact of these properties on micromirror performance is discussed. 相似文献
65.
Thermal decomposition of powdered ammonium perchlorate (AP), polystyrene (PS) and propellant, catalysed by freshly-prepared CuCr2O4 and mixtures of CuCr2O4 and CuO, has been studied with a low concentration (1% by mass) of the catalysts. It appears that decomposition is increased due to heterogeneous catalysis. The kinetics of thermal decomposition of AP in the presence of CuCr2O4 in the orthorhombic region of AP have also been studied. 相似文献
66.
M. Lal 《International Journal of Engineering Science》1983,21(7):825-832
The present paper seeks to solve the problem of an elastic half space under torsion by a flat annular rigid stamp in the linear micropolar elasticity. The problem is reduced to the solution of a system of four Fredholm integral equations of the second kind in four unknown functions. An iterative solution of these integral equations has been obtained for for the case of simple rotation through a small angle and the corresponding classical results have been obtained. 相似文献
67.
M. Lal 《Polymer International》1971,3(5):240-243
A computer technique for simulating configurational behaviour of chains, developed previously, was used to study the nature of the distribution of the magnitude of end-to-end vectors of excluded-volume chains constrained to two dimensions. The study revealed that the above distribution in the limit of infinite chain length deviates greatly from Gaussian behaviour and that the deviation is much greater than for three-dimensional chains. The probability distribution function A exp (—αR5.8) was derived. 相似文献
68.
Spatio-kinetic variation of methane oxidizing bacteria in paddy soil at mid-tillering: effect of N-fertilizers 总被引:2,自引:0,他引:2
S.K. Dubey 《Nutrient Cycling in Agroecosystems》2003,65(1):53-59
Laboratory experiments were conducted to evaluate the variation ofpopulation size of methanotrophs (MOB) and CH4 oxidation pattern inflooded rice soils sampled at three spatial points (rhizosphere, bulk and baresoils). Rhizosphere soil had higher MOB population size (301.1 ×105 cells g–1 dry soil) than bulk(37.2× 105 cells g–1 dry soil) andbare soil (19.1 × 105 cells g–1dry soil). The population size of MOB followed a decreasing trend with respectto fertilizer (urea NH4NO3 NH4Cl control). The result indicated that rhizosphere soil presented thestrongestCH4 oxidation activities, as shown by the highest values of the twokinetic parameters (K
m(app) andV
max). K
m andV
max increased significantly from bare to bulkto rhizosphere soil in control and fertilized soil and ranged from 6.2 to 133.2g g–1 dry soil and from 0.03 to 0.41g h–1 g–1 dry soil,respectively. The differences in K
m andV
max among the three soils (rhizosphere, bulkand bare) in this study could be due to differential species composition ofmethanotrophic community and/or to conditioning of MOB under different soilmicroenvironments. The present study has demonstrated a competitive inhibition effectof NH4
+-N on CH4 oxidation. 相似文献
69.
This paper provides a demonstration of harnessing the power of the Internet to enable collaborative manufacturing in such a setup where the key components such as the human resource personnel and the manufacturing equipment are geographically separated. As part of the framework a platform independent and cost-effective means of remotely operating a 3-axis computer numerical control (CNC) drilling machine securely via the Internet has been developed. In addition, an infrastructure to allow remote manufacturers to collaborate on a product design as well to monitor the drilling process in real time is presented. The framework rests on sound security foundation implemented using technologies such as firewall, authentication modules and transport layer security (TLS) protocol to promote safe usage of the drilling machine. It is worth mentioning that the architectural design is generic and modular in nature and as such, any other genre of CNC machine such as milling and turning could be substituted in place of drilling with only machine-specific changes to the existing system. 相似文献
70.
Abhishek Dubey Steve Nordstrom Turker Keskinpala Sandeep Neema Ted Bapty Gabor Karsai 《Innovations in Systems and Software Engineering》2007,3(1):33-52
Designing autonomic fault responses is difficult, particularly in large-scale systems, as there is no single ‘perfect’ fault
mitigation response to a given failure. The design of appropriate mitigation actions depend upon the goals and state of the
application and environment. Strict time deadlines in real-time systems further exacerbate this problem. Any autonomic behavior
in such systems must not only be functionally correct but should also conform to properties of liveness, safety and bounded
time responsiveness. This paper details a real-time fault-tolerant framework, which uses a reflex and healing architecture
to provide fault mitigation capabilities for large-scale real-time systems. At the heart of this architecture is a real-time
reflex engine, which has a state-based failure management logic that can respond to both event- and time-based triggers. We
also present a semantic domain for verifying properties of systems, which use this framework of real-time reflex engines.
Lastly, a case study, which examines the details of such an approach, is presented. 相似文献