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排序方式: 共有10000条查询结果,搜索用时 546 毫秒
991.
A. M. Kut’in V. S. Polyakov M. F. Churbanov G. E. Snopatin 《Inorganic Materials》2007,43(9):1018-1023
Using a flow method, we have measured the vapor pressure of tellurium tetraiodide, an attractive reagent for chemical vapor deposition technology. The results, combined with earlier tensimetric data, have been used to evaluate the basic thermodynamic functions of TeI4 and its thermolysis products. 相似文献
992.
993.
Various influence diagnostics in Multiple Discriminant Analysis can be found in the literature. Almost all of them are based
on the overall probability of misclassification. Two case-deletion diagnostics which evaluate the effect of the omission on
the linear functions which determine Fisher’s Linear Discriminant Rule are proposed in this paper. Both measures are based
on the L
2-norm: The first diagnostic is calculated from the data set and the second diagnostic is calculated in the minimum hypercube
which covers it. 相似文献
994.
A. D. Pogrebnyak M. V. Il’yashenko V. S. Kshnyakin V. V. Ponaryadov Sh. M. Ruzimov Yu. N. Tyurin 《Technical Physics Letters》2003,29(12):1028-1030
Chromium carbide-nickel coatings were deposited onto a technical grade copper substrate by means of a high-velocity plasma
jet of a plasmatron operating in specially selected regimes. An analysis of the coatings showed evidence of the formation
of a Ni-based solid solution, a complex chromium carbide (Cr7C3), and an fcc crystal phase with a lattice parameter of 3.614 Å. The surface of the coatings exhibits a characteristic relief
resulting from a dynamic interaction between melted and fused particles of the initial powder. The local hardness on some
areas of the surface and in depth of the coating reaches 66±4.5 HRC, while the coating adhesion strength varies from 25 to
300 MPa. 相似文献
995.
Geoffrey M. Eggert Paul R. Dawson Kapil K. Mathur 《International journal for numerical methods in engineering》1991,31(6):1031-1054
A forming model based on a viscoplastic flow formulation is derived which includes the effects of small elastic strains. A significant feature of the formulation is its reliance on the dominant inelastic material characteristics in the formation of the stiffness matrix for large strain problems. The resultant non-linear system of equations is solved by an adaptive descent method which combines the rapid convergence of Newton's method near the solution with the robustness of a method of successive approximations. The use of the adaptive descent method effectively extends the viscoplastic flow formulations into the nearly rate-insensitive range of behaviours exhibited, for example, by metals at low temperature, where slow convergence of the non-linear solution algorithm has traditionally hampered their use. 相似文献
996.
M.R. Kermani R.V. Patel M. Moallem 《Mechatronics, IEEE/ASME Transactions on》2005,10(2):181-188
In this paper, the application of high control authority piezostack actuators (PSAs) for active vibration control of large-scale flexible structures is studied. The idea is to add PSAs at appropriate locations of a flexible structure in order to strengthen its stiffness characteristics. In this regard, a flexible link of a macro-micro manipulator system actuated with PSAs is considered. The design of a mechanism for converting the force produced by a PSA to a bending moment is presented and a model for a system consisting of a flexible beam and a PSA is obtained. To this end, the solution of the governing partial differential equation with nonhomogeneous boundary conditions is obtained. Using singular value decomposition of the controllability Grammian of the system, optimum values for actuator parameters are obtained. The experimental results confirm that the suggested method can open up new possibilities in active vibration control of large-scale structures that require a large amount of control authority. 相似文献
997.
The nucleation of gas bubbles in extrusion foaming of high-pressure polyethylene is considered. Experiments show that undissolved gas microbubbles in the solution being foamed can have a significant effect on the number density of pores in the foam. A simple model for estimating the number density of supercritical nuclei is proposed. The effect of the time of mixing of gas and polymer in the extruder, the talc concentration, and the geometric characteristics of the nozzle on the number density of pores in the foam is analyzed. 相似文献
998.
A method for assessing health care technology that models the demand on the clinician's attention exerted by patients' data (diagnostic and therapeutic) can provide a means for simultaneously reducing the cost and improving the quality of health care. The attentional demand exerted by patients' data can be measured by the amount of uncertainty in the data. Uncertainty can be expressed mathematically by the concept of entropy in information theory. 相似文献
999.
Some methods determine the non-indolyl glucosinolates content in rapeseed as their hydrolysates: the isothiocyanates and the
oxazolidinethiones. These methods in their present form underestimate the amount of the glucosinolates content. In this investigation,
a modified method was developed to give a better quantitative estimate, indicating a glucosinolate level five times that obtained
by a typical existing method. 相似文献
1000.
T. Torounidis M. Westlund H. Sunnerud B.-E. Olsson P.A. Andrekson 《Photonics Technology Letters, IEEE》2005,17(2):312-314
Short return-to-zero pulses (/spl sim/2 ps) are generated at bit rates of 40, 80, and 160 Gb/s using a fiber-optical parametric amplifier. The performance of the parametric pulse source is evaluated both back-to-back and in a 110-km transmission link. A receiver sensitivity of -33 dBm back-to-back was achieved after demultiplexing from 160 to 10 Gb/s. The power penalty at 160 Gb/s due to 110-km transmission was less than 2 dB. Very short pulses (0.5 ps) were also achieved when using the parametric amplifier as a compressor. 相似文献