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881.
A novel communication technique is proposed, which utilizes a set ofmutually distinguishable optical pat terns instead of convergent facula to transmit information. Then the capacity is increased by exploiting the optical spatial bandwidth resources. At last, we experimentally demonstrate the proposed communication technique based on four 8 × 8 spatial pattern signals by using lenslet array processor. 相似文献
882.
Xiaobo Deng Rong Luo Hualin Chen Bailing Liu Yujun Feng Yuhai Sun 《Colloid and polymer science》2007,285(8):923-930
Composite latex particles of acrylate and polydimethylsiloxane (PDMS) with high PDMS content was prepared by emulsion copolymerization
and characterized by particle size analyzer, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR).
With gemini surfactant as the co-emulsifier in the system, the PDMS content in the system reached 50%, which was far higher
than the other reported values. Through the characterization of the particle size analyzer, the particle size augmented with
the increase of the amount of PDMS, which could be said that the polysiloxane had participated into the reaction and had been
introduced into the colloid particle. The results of FTIR indicated that almost all the monomer had been exhausted in the
reaction because there was no C=C and D4 characteristic peaks in the spectrum. Besides the surface properties also were measured by surface tension analysis, water
absorption, and the static contact angle, it could be found that with the increase of polysiloxane content, the excellent
properties acquired by PDMS were clearly revealed by the findings, such as the decrease of surface tension and water absorption,
and the increase of static contact angle. All the measurements were consistent with the conclusion that the composite latex
particles of polysiloxane and acrylate with high siloxane content had been prepared successfully. 相似文献
883.
一个近-三角剖分嵌入是指一个曲面上的嵌入图使得几乎所有的面都是三角形,至多只有一个可能的例外.文中作者证明了如下结论:如果一个图G 在球面S0(或环面S1)上有近-三角剖分嵌入,那么G在每一个可定向曲面Sk有近-三角剖分嵌入,其中k=h,h+1,\cdots ,\lfloor\frac{\beta(G)}{2}\rfloor$, 而h=0(或1)并且β(G)是图G的Betti数.特别地,G是上可嵌入的. 相似文献
884.
This paper considers the existence and uniqueness of solutions of an age-structured population model in a spatially heterogeneous bounded environment. The model describes individual organism movement of diffusion and advection in the older life stage but assumes stationarity of individuals in the embryonic stage. The mathematical formulation is a nonlinear degenerate parabolic partial differential problem with non-locally integro-type initial-boundary conditions. 相似文献
885.
886.
A finite difference approximation to a
hierarchical size-structured model with nonlinear growth,
mortality and reproduction rates is developed.
Existence-uniqueness of the weak solution to the model is
established and convergence of the finite-difference approximation
is proved. Simulations indicate that the monotonicity assumption on the
growth rate is crucial for the global existence of weak solutions.
Numerical results testing the efficiency of this
method in approximating the long-time behavior of the model are
presented. 相似文献
887.
探讨了推广EZ模型的可能性,并给出了相应的模型中人群大小分布函数的形式解.研究表明金融市场中不同大小的人群数目的交易人的数目在重新标度后将具有最广泛的普适性行为
关键词:
金融物理
人群效应
主方程 相似文献
888.
We study the dynamic critical behavior of the local bond-update (Sweeny) dynamics for the Fortuin-Kasteleyn random-cluster model in dimensions d=2, 3 by Monte Carlo simulation. We show that, for a suitable range of q values, the global observable S2 exhibits "critical speeding-up": it decorrelates well on time scales much less than one sweep. In some cases the dynamic critical exponent for the integrated autocorrelation time is negative. We also show that the dynamic critical exponent zexp is very close (possibly equal) to the rigorous lower bound alpha/nu and quite possibly smaller than the corresponding exponent for the Chayes-Machta-Swendsen-Wang cluster dynamics. 相似文献
889.
Mathematical Programming - Functional constrained optimization is becoming more and more important in machine learning and operations research. Such problems have potential applications in... 相似文献
890.
Jianpeng Li Dingshu Xiao Peichu Wang Hongyan Chen Minghua Deng Degang Zhu Jie Yu 《Particle & Particle Systems Characterization》2023,40(1):2200141
Transition metal compounds anchored on N-doped carbon (NC) show intrinsic activity and stability for oxygen reduction reaction (ORR). However, the interaction between the transition metal compounds and NC still needs to be strengthened for electron transfer at the compounds/carbon interface. Herein, Fe/Fe3C hybrid nanoparticles encapsulated into N-doped carbon (Fe@NC) are used as high-performance ORR catalysts. Benefiting from the strong interaction at Fe/Fe3C nanoparticles/NC interface, the electrons can transfer from Fe/Fe3C hybrid nanoparticles to NC, redistributing the electron density of active sites and promoting the ORR process. The as-synthesized Fe@NC exhibits outstanding ORR catalytic activity with an onset potential of 1.01 V and a half-wave potential of 0.92 V in alkaline media. It also shows prominent cycling stability and tolerance to methanol crossover, superior to Pt/C catalyst. The theoretical analysis reveals that the Fe nanoparticles have regulated the electron distributions at the heterojunction interface. The Gibbs free energy diagrams for ORR illustrate that the rate-determining step is the conversion of OH* to OH−. In situ Raman spectra give evidence of O-containing intermediates to prove the ORR process. 相似文献