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排序方式: 共有818条查询结果,搜索用时 140 毫秒
1.
Shannon Lee Scott L. Carnahan Georgiy Akopov Philip Yox Lin-Lin Wang Aaron J. Rossini Kui Wu Kirill Kovnir 《Advanced functional materials》2021,31(16):2010293
Noncentrosymmetric (NCS) tetrel pnictides have recently generated interest as nonlinear optical (NLO) materials due to their second harmonic generation (SHG) activity and large laser damage threshold (LDT). Herein nonmetal-rich silicon phosphides RuSi4P4 and IrSi3P3 are synthesized and characterized. Their crystal structures are reinvestigated using single crystal X-ray diffraction and 29Si and 31P magic angle spinning NMR. In agreement with previous report RuSi4P4 crystallizes in NCS space group P1, while IrSi3P3 is found to crystallize in NCS space group Cm, in contrast with the previously reported space group C2. A combination of DFT calculations and diffuse reflectance measurements reveals RuSi4P4 and IrSi3P3 to be wide bandgap (Eg) semiconductors, Eg = 1.9 and 1.8 eV, respectively. RuSi4P4 and IrSi3P3 outperform the current state-of-the-art infrared SHG material, AgGaS2, both in SHG activity and laser inducer damage threshold. Due to the combination of high thermal stabilities (up to 1373 K), wide bandgaps (≈2 eV), NCS crystal structures, strong SHG responses, and large LDT values, RuSi4P4 and IrSi3P3 are promising candidates for longer wavelength NLO materials. 相似文献
2.
Automation and Remote Control - We consider multicriteria minimax optimization problems with criteria in the form of the maxima of functionals given by the induced norms of linear operators taking... 相似文献
3.
D Brown S Kogan E Lagasse I Weissman M Alcalay PG Pelicci S Atwater JM Bishop 《Canadian Metallurgical Quarterly》1997,94(6):2551-2556
The malignant cells of acute promyelocytic leukemia (APL) contain a reciprocal chromosomal translocation that fuses the promyelocytic leukemia gene (PML) with the retinoic acid receptor alpha gene (RAR alpha). To test the hypothesis that the chimera PMLRAR alpha plays a role in leukemogenesis, we expressed a PMLRAR alpha cDNA in myeloid cells of transgenic mice. PMLRAR alpha transgenic mice exhibited impaired neutrophil maturation early in life, which progressed at a low frequency over the course of several months to overt APL. Both the preleukemic state and the leukemia could be transplanted to nontransgenic mice, and the transplanted preleukemia could progress to APL. The APL recapitulated features of the human disease, including a response to retinoic acid. Retinoic acid caused the leukemic cells to differentiate in vitro and in vivo, eliciting remissions of both the preleukemic state and APL in mice. Our results demonstrate that PMLRAR alpha impairs neutrophil differentiation and initiates the development of APL. The transgenic mice described here provide an apparently accurate model for human APL that includes clear evidence of tumor progression. The model should be useful for exploring the molecular pathogenesis of APL and the mechanisms of the therapeutic response to retinoic acid, as well as for preclinical studies of therapeutic regimens. 相似文献
4.
It is shown that the features of La2–x(Ba,Sr)xCuO4 around x=0.125 can be. treated as a consequence of alternate-layer doping when doped holes are added to each second CuO2 plane. The model of heterovalence doping of high-Tc superconductors (HTSC) is proposed to account for the evolution of HTSC properties with doping. According to this model the transition from insulator to metal state under doping proceeds through the stage of-U-centers formation, which arise when the definite spatial arrangement of the doping atoms is realized. 相似文献
5.
This article presents and evaluates the performance of a location sensing algorithm developed and demonstrated at Carnegie Mellon University. We compare our model with various others based on different architectures and software paradigms. We show comparative results in accuracy, the complexity of training, total power consumption, and suitability to users. Our method reduces training complexity by a factor of eight over previous algorithms, and yields noticeably better accuracy. The algorithm uses less power than previous models, and offers a more secure privacy model. 相似文献
6.
Coffman E.G. Jr. Igelnik B.M. Kogan Y.A. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》1991,37(5):1379-1387
A stochastic model of buffering in a data communication system is considered, with source and sink transmission parameters depending on the number of active sources. For models in this control setting the authors analyze an effective numerical method for evaluating the equilibrium distribution of buffer content. The theoretical basis of the method is established first. Then, it is shown that the method has the same complexity, in terms of the total number of sources, as known analytical methods for the model with constant parameters. Asymptotics for tail probabilities at high buffer levels and under heavy load are also derived, and the complexity of their computation is compared with that of evaluating explicit formulas. In comparison to earlier results this approach reduces the complexity of computing the probability of overflow and its asymptotic estimates. The speed-up stems from the application of interpolation schemes 相似文献
7.
Necessary and sufficient conditions for robust stability of a family of polynomials with complex coefficients are provided. This work generalizes a frequency-domain criteria for robust stability of continuous linear systems reported on by Y.Z. Tsypkin and B.T. Polyak (1991) 相似文献
8.
An optimal control approach to continuous-time aggregate production planning problems is presented. The proposed approach describes the production and capacity evolution (expansion, sell and deterioration) processes in the form of differential equations with regular production, subcontracting and capacity change rates controllable on one hierarchical level. In this way, the traditional disadvantages of the two-level problem consideration (one level for strategic capacity planning and the other for production smoothing) are avoided. Analytical properties for optimal production and capacity control regimes and conditions for their changeover are derived by the maximum principle. Based on these results, an insight into the optimal behaviour of the production system is gained and a fast numerical method is developed to identify and sequence the optimal regimes for arbitrary demand profiles. A computational example illustrates the effectiveness of the approach. 相似文献
9.
10.
Journal of Mathematical Imaging and Vision - A correction to this paper has been published: https://doi.org/10.1007/s10851-021-01028-0 相似文献