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排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
基于XML和N层VSM的Web信息检索 总被引:2,自引:1,他引:1
基于XML文档格式良好、层次清晰,可以方便地操纵、分析其结构的特点。文中在将Web上的HTML文档转化为XML文档的基础上,通过Java中的DOM树,分析文档的层次结构。把文档分为层次化的文本段,对传统的VSM算法进行改进,把每个文本段转换为空间向量,实现了N层VSM算法,通过试验证明,改进后算法的查全率和查准率都要优于传统的VSM算法。 相似文献
993.
Yu. P. Pyt’ev I. I. Falomkin A. I. Chulichkov 《Pattern Recognition and Image Analysis》2006,16(3):523-528
A new method for compression of grayscale images containing a small number of graphical elements is proposed. The method is
characterized by high compression ratios, small losses, and good readability of the processed images. It is based on morphological
methods of image analysis and could be used to store images of documents produced by fax machines, scanners, etc.
Igor I. Falomkin. Born 1979. Graduated from the Faculty of Physics, Moscow State University, in 2001. Scientific interests: image analysis
and recognition, analysis and interpretation of experimental data. 相似文献
994.
A. I. Ageev I. V. Bogdanov V. V. Zubko S. S. Kozub P. I. Slabodchikov V. V. Sytnik L. M. Tkachenko P. A. Shcherbakov K. Blachet J. Cauhertz G. Moritz 《Atomic Energy》2002,93(6):957-960
The superconducting dipoles developed as part of the UNK project have reached a magnetic field 6 T at a rate of up to 0.8 T/sec. Experimental data are presented on the conditioning, rate dependences, and dynamic losses for magnets with two types of superconducting cable (zebra and oxide). Possible ways to decrease the heat release in a dipole operating in rapid-cycling magnetic fields are examined. The results of an analysis of heat release and temperature conditions are presented for a dipole with a winding made of improved current-carrying components. 相似文献
995.
V. A. Melent'ev I. M. Mityushina 《Power Technology and Engineering (formerly Hydrotechnical Construction)》1985,19(5):241-246
Conclusion On the basis of the foregoing conditions about the design of hydraulic-fill dams and technology of their construction and also with consideration of the results of comparative calculations of the permeability of these dams, for the upper reservoirs of pumped-storage stations we can recommend dams which have reliable impervious elements, namely, a diaphragm, facing, or placed clay core.Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 5, pp. 31–35, May, 1985. 相似文献
996.
Translated from Izmeritel'naya Tekhnika, No. 7, pp. 40–41, July, 1989. 相似文献
997.
The use of well characterized laboratory animals in biomedical research is of importance for quality securing and reproducibility of animal experiments. Therefore, breeders should not only have in mind the reproduction of their animal stocks, but they should also be interested to achieve an optimal resemblance of the animals in the main traits characterizing them as a model of human diseases. Specific software applications which helps the breeders in monitoring the main breeding parameters, selecting suitable breeding pairs and data processing are practically not available. This prompted us to develop a computer program for management of breeding and experimental data, which we called BB_RADABA. In this report we want to give a short survey on this computer program. 相似文献
998.
Vardiambasis I.O. Tsalamengas J.L. Fikioris J.G. 《Antennas and Propagation, IEEE Transactions on》1998,46(10):1571-1579
Plane wave scattering by single or double slots loaded with semicircular dielectric cylinders is investigated in the most general case of oblique incidence and arbitrary polarization. To this end, systems of singular integral-integrodifferential equations of the first kind are constructed and discretized on the basis of recently developed algorithms. Several internal tests and extensive comparisons with available results were made in order to validate the numerical codes. Plotted results both for the surface magnetic current densities and the radar cross sections reveal how the scattering properties may be controlled by changing several physical and geometrical parameters of the structure 相似文献
999.
1. At a holding potential of -40 mV, carbachol (50 microM) produced a complex pattern of inward currents in single smooth muscle cells freshly isolated from the mouse anococcygeus. Membrane currents were monitored by the whole-cell configuration of the patch-clamp technique. Previous work has identified the first, transient component as a calcium-activated chloride current (ICl(Ca)) and the second sustained component as a store depletion-operated non-selective cation current (I(DOC)). The object of the present study was to examine the cellular mechanisms underlying the third component, a series of inward current oscillations (I(oscil)) superimposed on I(DOC). 2. Carbachol-induced I(oscil) (amplitude 97 +/- 11 pA; frequency 0.26 +/- 0.02 Hz) was inhibited by the chloride channel blocker anthracene-9-carboxylic acid (A-9-C; 1 mM), and by inclusion of 1 mM EGTA in the patch-pipette filling solution. 3. In calcium-free extracellular medium (plus 1 mM EGTA), carbachol produced an initial burst of oscillatory current which lasted 94 s before decaying to zero; I(oscil) could be restored by re-admission of calcium. The frequency, but not the amplitude, of I(oscil) increased with increasing concentrations of extracellular calcium (0.5-10 mM). 4. Inclusion of the inositol triphosphate (IP3) receptor antagonist heparin (5 mg ml(-1) in the patch-pipette filling solution, or pretreatment of cells with the sarcoplasmic reticulum (SR) calcium ATPase inhibitor cyclopiazonic acid (CPA; 10 microM), prevented the activation of I(oscil) by carbachol. Caffeine (10 mM) activated both ICl(Ca) and I(DOC) and prevented the induction of I(oscil) by carbachol. Caffeine and CPA also abolished I(oscil) in the presence of carbachol, as did both a low (3 microM) and a high (30 microM) concentration of ryanodine. 5. Carbachol-induced I(oscil) was abolished by the general calcium entry blocker SKF 96365 (10 MM) and by Cd2+ (100 microM), but was unaffected by La3+ (400 microM). As found previously, I(DOC) was also blocked by SKF 96365 and Cd2+, but not La3+; the inhibition of I(DOC) preceded the abolition of I(oscil) by 27 s with SKF 96365 and by 30 s with Cd2+. Nifedipine (1 microM) produced a partial inhibition of the carbachol-induced I(oscil) frequency at holding potentials of -20 mV and -60 mV and, in addition, reduced I(DOC) at -60 mV by 18%. 6. It is concluded that carbachol-induced inward current oscillations in mouse anococcygeus cells are due to a calcium-activated chloride current, and reflect oscillatory changes in cytoplasmic calcium ion concentration. These calcium oscillations are derived primarily from the SR stores, but entry of calcium into the cell is necessary for store replenishment and maintenance of the oscillations. Capacitative calcium entry (via I(DOC) appears to be important not only for sustained contraction of this tissue, but also as a route for re-filling of the SR and, therefore, represents an important target for the development of novel and selective drugs. 相似文献
1000.
G Fernl?f I Gadhasson K P?dra PO Darnerud A Thuvander 《Canadian Metallurgical Quarterly》1997,90(2-3):189-197
The structural similarities between polybrominated diphenyl ethers and immunotoxic halogenated aromatic compounds suggest that the polybrominated diphenyl ethers might affect the immune system. The present study was undertaken to investigate the immunological effects of some purified PBDE-congeners on human lymphocyte function in vitro. Polychlorinated biphenyl congeners were also included in the study. Mitogen-induced DNA synthesis and immunoglobulin synthesis by lymphocytes from blood donors were examined following polybrominated diphenyl ether or polychlorinated biphenyl exposure in vitro in order to determine the immunotoxic potential of these substances. No effects on mitogen-induced proliferation or immunoglobulin synthesis were observed after exposure of cells to concentrations up to 10(-5) M. The negative findings in this study indicate that certain functions of human peripheral lymphocytes, i.e. proliferation and immunoglobulin synthesis, are insensitive to the direct action of polybrominated diphenyl ethers and polychlorinated biphenyls. Our results are in accordance with other recent studies in which no effects on immunological parameters were demonstrated by exposure of lymphocytes to polyhalogenated aromatic hydrocarbons in vitro. 相似文献