基于数据驱动加权的模糊评价量化方法

模糊评价改变了量化打分的评价方式,使评价者能够更加客观的进行评价,因此在各行各业有着广泛的应用。但是如何将模糊评价转化为量化分值,以便对被评价者进行评价一直是不少学者研究的重点。本文提出一种将模糊评价进行量化评分的新方法,并提出了一种以评价数据来驱动各项指标权重的方法。     

非线性混合似变分不等式的扰动近似点-投影算法

In this paper we introduce a new perturbed proximal-projection algorithm for finding the common element of the set of fixed points of non-expansive mappings and the set of solutions of nonlinear mixed variational-like inequalities. The convergence criteria of the iterative sequences generated by the new iterative algorithm is also given. Our approach and results generalize many known results in this field.     

Levitin-poyak well-posedness of generalized vector equilibrium problems with functional constraints

In this article, we study Levitin-Polyak type well-posedness for generalized vector equilibrium problems with abstract and functional constraints. Criteria and characterizations for these types of well-posednesses are given.     

Global asymptotic stability of positive equilibrium of three-species Lotka–Volterra mutualism models with diffusion and delay effects

In the mutualism system with three species if the effects of dispersion and time delays are both taken into consideration, then the densities of the cooperating species are governed by a coupled system of reaction–diffusion equations with time delays. The aim of this paper is to investigate the asymptotic behavior of the time-dependent solution in relation to a positive uniform solution of the corresponding steady-state problem in a bounded domain with Neumann boundary condition, including the existence and uniqueness of a positive steady-state solution. A simple and easily verifiable condition is given to ensure the global asymptotic stability of the positive steady-state solution. This result leads to the permanence of the mutualism system, the instability of the trivial and all forms of semitrivial solutions, and the nonexistence of nonuniform steady-state solution. The condition for the global asymptotic stability is independent of diffusion and time-delays as well as the net birth rate of species, and the conclusions for the reaction–diffusion system are directly applicable to the corresponding ordinary differential system and 2-species cooperating reaction–diffusion systems. Our approach to the problem is based on inequality skill and the method of upper and lower solutions for a more general reaction–diffusion system. Finally, the numerical simulation is given to illustrate our results.     

A semiclassical dynamics study of the photoisomerization of methyl-substituted azobenzene

A semiclassical dynamics simulation study is reported for a trans–cis photoisomerization cycle of four azo compounds, including azobenzene, 2-methylazobenzene, 2,6-dimethylazobenzene, and 2,2′-dimethylazobenzene. For both trans?→?cis and cis?→?trans isomerization processes, each compound is excited by a 50?fs (fwhm) laser pulse with a photon energy leading to a ππ* excitation. It is found that the compound in both cases follows a rotational path from reactant to product and that the isomerization dynamics is significantly affected by substitution. The relative times for completing a trans–cis isomerization cycle for four compounds, 2,6-dimethylazobenzene?>?2,2-dimethylazobenzene and 2,6-dimethylazobenzene?>?2-methylazobenzene>?azobenzene, follow the same order as for the photoinduced formation of the surface relief grating of polymers based on these four compounds. The simulation results provide a basis for understanding the surface relief grating formation of azobenzene-based materials upon irradiation with laser beams.     

Consensus problems of first-order dynamic multi-agent systems with multiple time delays

Consensus problems of first-order multi-agent systems with multiple time delays are investigated in this paper. We discuss three cases: 1) continuous, 2) discrete, and 3) a continuous system with a proportional plus derivative controller. In each case, the system contains simultaneous communication and input time delays. Supposing a dynamic multi-agent system with directed topology that contains a globally reachable node, the sufficient convergence condition of the system is discussed with respect to each of the three cases based on the generalized Nyquist criterion and the frequency-domain analysis approach, yielding conclusions that are either less conservative than or agree with previously published results. We know that the convergence condition of the system depends mainly on each agent’s input time delay and the adjacent weights but is independent of the communication delay between agents, whether the system is continuous or discrete. Finally, simulation examples are given to verify the theoretical analysis.     

天顶附近三轴光电跟踪系统Z轴运动状态分析

针对三轴光电跟踪系统在地平式盲区内的跟踪策略所具有的多样性,对天顶附近三轴光电跟踪系统Z轴运动状态进行了分析.仿真结果表明：地平式盲区内Z轴做匀角速运动有利于     

有耗介质层上多导体传输线的电磁耦合时域分析方法

目前,针对空间电磁场作用有耗介质层上传输线的电磁耦合,仍缺乏有效的数值分析方法.因此,本文提出一种高效的时域混合算法,很好地解决了有耗介质层上传输线电磁耦合建模难的问题.首先,对经典传输线方程进行改进,推导了适用于有耗介质层上多导体传输线电磁耦合分析的修正传输线方程.然后,结合时域有限差分方法和相应插值技术,求解修正传输线方程,获得多导线及其端接负载上的电压和电流响应,并实现空间电磁场辐射与多导线瞬态响应的同步计算.最后,通过相应计算实例的数值模拟,与CST软件的仿真结果进行对比,验证了时域混合算法的正确性和高效性.     

A super-junction SOI-LDMOS with low resistance electron channel

A novel super-junction LDMOS with low resistance channel(LRC), named LRC-LDMOS based on the silicon-oninsulator(SOI) technology is proposed. The LRC is highly doped on the surface of the drift region, which can significantly reduce the specific on resistance(Ron,sp) in forward conduction. The charge compensation between the LRC, N-pillar,and P-pillar of the super-junction are adjusted to satisfy the charge balance, which can completely deplete the whole drift,thus the breakdown voltage(BV) is enhanced in reverse blocking. The three-dimensional(3 D) simulation results show that the BV and R_(on,sp) of the device can reach 253 V and 15.5 mΩ·cm~2, respectively, and the Baliga's figure of merit(FOM = BV~2/R_(on,sp)) of 4.1 MW/cm~2 is achieved, breaking through the silicon limit.     

Y掺杂WS2二维材料的第一性原理研究

WS₂由于其优异的物理和光电性质引起了广泛关注。本研究基于第一性原理计算方法,探索了本征单层WS₂及不同浓度W原子替位钇(Y)掺杂WS₂的电子结构和光学特性。结果表明本征单层WS₂为带隙1.814 eV的直接带隙半导体。进行4%浓度(原子数分数)的Y原子掺杂后,带隙减小为1.508 eV,依旧保持着直接带隙的特性,随着Y掺杂浓度的不断增大,掺杂WS₂带隙进一步减小,当浓度达到25%时,能带结构转变为0.658 eV的间接带隙,WS₂表现出磁性。适量浓度的掺杂可以提高材料的导电性能,且掺杂浓度增大时,体系依旧保持着透明性并且在红外光和可见光区对光子的吸收能力、材料的介电性能都有着显著提高。本文为WS₂二维材料相关光电器件的研究提供了理论依据。