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11.
Analysis and design of modified Wollaston prisms   总被引:6,自引:0,他引:6  
Montarou CC  Gaylord TK 《Applied optics》1999,38(31):6604-6616
An exact analysis of the working parameters of a modified Wollaston prism is presented. Parameters include the output splitting angle, the retardation, and the location of the plane of the interference fringes (plane of apparent splitting). Results are presented for the entire range of optical axis inclinations and wedge angles. Approximate expressions from the literature are evaluated. An angle of incidence that causes the plane of the interference fringes to be perpendicular to the axis of the optical system is found for each configuration analyzed. This is then applied to the design of modified Wollaston prisms for Nomarski differential interference contrast microscopy.  相似文献   
12.
A theory of the stress-induced crystallization of polymeric networks is presented which takes into account 1) the free energy of fusion, 2) crystal surface energies and 3) entropic changes in the amorphous sections of crystallizing chains. It is assumed that the vector running from one end to the other of the crystallite is oriented in the direction of network extension, irrespective of crystal morphology, thus minimizing the free energy of crystallization. Assuming that the network assumes the crystal morphology which minimizes the free energy of the network at a given degree of crystallinity and that the crystallization proceeds along this lowest free energy path, it is predicted for simple network extension that growth of a perfectly oriented extended-chain crystal occurs initially, changing to a one-fold crystal oriented perpendicular to extension at low extension and to a two-fold crystal having nearly perfect orientation at High extension. The stress is predicted to decay initially and then to rise as the network chains switch from an extended-to a folded-chain morphology. Spatial factors which may trap chains in the ex tended-chain morphology or prematurely stopping the crystallization process can result in a mixed crystal morphology. At high extension, the structure is similar to that of the shish kebab.  相似文献   
13.
14.
Regimes of parallel and turbulent flow in a parallel plate precipitator are discussed as theoretical idealizations. Particle trajectories and resultant efficiency of an ideal parallel flow device are described and compared with the Deutsch equation analysis, based upon complete mixing in turbulent flow, for a single mobility species. A relationship is developed between particle size and mobility which incorporates field and diffusion charging and the Cunningham correction to Stoke's drag. Log normal distributions of particle size are transformed into mobility distribution functions. Efficiencies based upon parallel flow and turbulent mixing are expressed for the particle mobility distributions by finding incremental efficiencies for each segment of a given distribution and weighting each segment by its relative proportion of the whole. These efficiencies are compared with each other and with the result obtained by inserting the mean mobility into the Deutsch equation. It is shown that, for relatively high standard deviation, use of an average mobility value in the Deutsch equation can result in device efficiency characteristics quite similar to those resulting from collection of the various mobility species in parallel flow. A much lower efficiency results from incremental analysis of the same distribution under the assumption of turbulent mixing.  相似文献   
15.
A summary of electrical and optical approaches to clock distribution within high-performance microprocessors is presented. System-level properties of intrachip electrical clock distribution networks corresponding to three microprocessor families are summarized. It is found that global clock interconnect performance and short-term jitter present the greatest challenges to the continued use of conventional clock distribution methodologies. An extrapolation of trends describing the percentage of clock period consumed by global skew and short-term jitter identifies the 32-nm technology generation of the 2002 International Technology Roadmap for Semiconductors (ITRS) as the first technology generation within which alternate methods of clock distribution may be warranted. Research efforts investigating interboard through intrachip optical clock distribution are also summarized. An optical distribution network compatible with high volume manufacturing in conjunction with a suitable means of providing optical-to-electrical signal conversion comprise the two fundamental challenges facing successful implementation of an optical clock distribution network. It is found that a global guided-wave distribution capable of efficient input and output coupling of optical power is required to meet the first challenge. The identification of a suitable means of optical-to-electrical conversion, however, remains an active topic of research.  相似文献   
16.
An electrical-optical chip input-output (I/O) interconnection technology called sea of polymer pillars (SoPP) is presented. SoPP provides highly process-integrated and mechanically flexible (compliant) electrical-optical die-to-board interconnections that mitigate thermo-mechanical expansion mismatches. The I/O density of SoPP exceeds 10/sup 5//cm/sup 2/. The compliance of the polymer pillars is shown to be 3-5 /spl mu/m/mN. Approximately 50% input optical coupling efficiency into a volume grating coupler through a set of polymer pillars is demonstrated.  相似文献   
17.
The predictions of several entanglement models of rubber elasticity for the uniaxial stress-strain response of crosslinked polymer networks are examined. It is found that the Gaylord tube model and the Flory constrained junction fluctuation model both agree well with the experimental data.  相似文献   
18.
A numerical method is described that provides the means for optimizing any objective function representing a general multilayer integrated optics waveguide. In this way, the physical parameters of the multilayer structure can be set so that the performance of the device is optimized. The method uses any standard numerical minimization algorithm in conjunction with the argument principle method. The method has been successfully applied for the optimization of a multilayer immunosensor and a TE-mode polarizer. The advantages of the method are its generality, its efficiency, its accuracy, and its applicability to a wide range of planar integrated optics devices  相似文献   
19.
Summary Theoretical interpretations of the viscoelastic relaxation behavior of cross-linked elastomers are discussed. The dangling chain retracing mechanisms of deGennes and Pearson-Helfand, which assume that the stress contribution of a dangling chain decreases as it assumes successively lower entropy configurations, are replaced by an alternative relaxation mechanism, based on the hopping model of hindered diffusion.  相似文献   
20.
Memorializes Frederick Duane Sheffield and his work, which reflected a lifelong commitment to the contiguity theory of learning under the tutelage of E. R. Guthrie. His published experimental work and interactions with colleagues and students during his career at Yale are highlighted. Sheffield is remembered for his 1951 Psychological Review article, "The Contiguity Principle in Learning Theory," in which he defended and expanded Guthrie's views, and for his criticism of the need and drive-reduction theories that dominated Yale in the 1940s. In 3 experiments in the early 1950s, he showed that neither need nor drive reduction was necessary to induce learning. The findings were interpreted as showing that it was the onset of stimulation, not the reduction in drive or need, that was reinforcing. This became broadly known as Sheffield's drive-induction theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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