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排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
J. Jiang Fanghua Mei W. J. Meng G. B. Sinclair Sunggook Park 《Microsystem Technologies》2008,14(6):815-819
For direct imprinting of metals, hard materials such as diamond and SiC have been used to construct mold inserts in preference
to Si, despite the ease in fabricating Si-based micro-/nano- scale structures. In this communication, we demonstrate that
micron scale Al structures can be replicated with good fidelity at room temperature by compression molding with Si inserts
without incurring insert damage. We further report on results of a finite element analysis of the mechanics of the molding
process. The finite element results provide some understanding of the observed lack of damage to the Si inserts. 相似文献
52.
Image preview is a convenient way to browse large or multiple images on small displays. However, current signal-level image
resampling algorithms may remove many features of interest in the preview image. In this paper, we propose perceptual image
preview which retains more perceptual features such that users can inspect features of interest by viewing the preview image
only and without zooming in. This technology has two components, structure enhancement and perceptual feature visualization.
Structure enhancement enhances the image structure while suppressing subtle details using a gradient modulation method, thus
making the succedent perceptual features more apparent. For perceptual feature visualization, features of interest detected
in the picture is visualized on the structure enhanced preview image. We demonstrate with two examples of most commonly used image quality features, image blur and noise. The effectiveness of the proposed method is validated
by experimental results. 相似文献
53.
About 20 years ago, Markus and Robey noted that most research on IT impacts had been guided by deterministic perspectives and had neglected to use an emergent perspective, which could account for contradictory findings. They further observed that most research in this area had been carried out using variance theories at the expense of process theories. Finally, they suggested that more emphasis on multilevel theory building would likely improve empirical reliability. In this paper, we reiterate the observations and suggestions made by Markus and Robey on the causal structure of IT impact theories and carry out an analysis of empirical research published in four major IS journals, Management Information Systems Quarterly (MISQ), Information Systems Research (ISR), the European Journal of Information Systems (EJIS), and Information and Organization (I&O), to assess compliance with those recommendations. Our final sample consisted of 161 theory-driven articles, accounting for approximately 21% of all the empirical articles published in these journals. Our results first reveal that 91% of the studies in MISQ, ISR, and EJIS focused on deterministic theories, while 63% of those in I&O adopted an emergent perspective. Furthermore, 91% of the articles in MISQ, ISR, and EJIS adopted a variance model; this compares with 71% from I&O that applied a process model. Lastly, mixed levels of analysis were found in 14% of all the surveyed articles. Implications of these findings for future research are discussed. 相似文献
54.
55.
This paper reports on recent results in a series of the work of the authors on the stability and nonlinear control for general
dynamical systems described by retarded functional differential and difference equations. Both internal and external stability
properties are studied. The corresponding Lyapunov and Razuminkhin characterizations for input-to-state and input-to-output
stabilities are proposed. Necessary and sufficient Lyapunov-like conditions are derived for robust nonlinear stabilization.
In particular, an explicit controller design procedure is developed for a new class of nonlinear time-delay systems. Lastly,
sufficient assumptions, including a small-gain condition, are presented for guaranteeing the input-to-output stability of
coupled systems comprised of retarded functional differential and difference equations. 相似文献
56.
High fidelity repeater false-target badly affects a radar system’s detecting, tracking, and data processing. It is an available approach of confronting false-target for radar that discriminates firstly and then eliminates. Whereas for the technique progress about the repeater false-target jam, it is more and more difficult to discriminate this jam in the time-domain, frequency-domain, or space-domain. The technique using polarization information to discriminate the target and false-target is discussed in th... 相似文献
57.
Zhixue Wu 《Structural and Multidisciplinary Optimization》2009,37(6):625-634
The goal of this work is to obtain optimal hole shape for minimum stress concentration in two-dimensional finite plates using
parameterized geometry models. The boundary shape for a hole is described by two families of smooth curves: one is a “generalized
circular” function with powers as two parameters; the other one is a “generalized elliptic” function
a and b are ellipse axes) with powers as two parameters and one of the ellipse axes as the third parameter. Special attention is
devoted to the practicability of parameterized equations and the corresponding optimal results under the condition with and
without the curvature radius constraint. A number of cases were examined to test the effectiveness of the parameterized equations.
The numerical examples show that extremely good results can be obtained under the conditions with and without curvature radius
constraint, as compared to the known solutions in the literature. The geometries of the optimized holes are presented in a
form of compact parametric functions, which are suitable for use and test by designers. It is anticipated that the implementation
of the suggested parameterized equations would lead to considerable improvements in optimizing hole shape with high quality. 相似文献
58.
Computational Economics - The study aims to analyze and forecast Internet financial risks based on the model based on deep learning and the Back Propagation Neural Network (BPNN). First, the theory... 相似文献
59.
Yan-kun Tang Qian Yang Xiao-fei Si Jin-kang Han Wei-wei Cao Ya-fei Li Fang Liu Xiaoyan Yao Ya Zhai 《Journal of Superconductivity and Novel Magnetism》2017,30(6):1527-1531
In this study, we report the results of an investigation into the sintering temperature dependence of magnetic and transport properties for GdBaCo2 O 5 + δ synthesized through a sol-gel method. The lowering of sintering temperature leads to the increase of oxygen content and the reduction of grain size. The increase of oxygen content results in the enhancement of magnetic interactions and the weakening of Coulomb repulsion effect, while the reduction of grain size improves the magnetoresistance effect. Metal-insulator transition accompanied with spin-state transition is observed in all samples. 相似文献
60.
The purpose of this study is to analyze the environmental pollution effects elicited by industrial agglomeration and to devise necessary changes before and after China going into the New Normal, a contemporary phase of less rapid but more sustainable economic development. An empirical model is constructed based on the Copeland–Taylor model, and empirical research is conducted using statistical panel data derived from 285 Chinese cities between 2003 and 2014. To study the relationship between industrial agglomeration and industrial pollutant emission both before and after the ‘New Normal,’ the sample data are divided into two time periods: 2003–2008 and 2009–2014. Estimated results are as follows. First, industrial agglomeration exacerbates industrial pollution levels overall although the negative environmental effect of industrial agglomeration is weakened following China’s entry into the New Normal phase of economy. Second, both the interaction term of industrial agglomeration and foreign direct investment (FDI) and the interaction term of industrial agglomeration and environmental regulation are negatively related to industrial agglomeration. These findings indicate that FDI and environmental regulation can indirectly reduce industrial pollutant emissions by way of industrial agglomeration. 相似文献