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941.
942.
On an Extended Lagrange Claim 总被引:1,自引:0,他引:1
Lagrange once made a claim having the consequence that a smooth function f has a local minimum at a point if all the directional derivatives of f at that point are nonnegative. That the Lagrange claim is wrong was shown by a counterexample given by Peano. In this note, we show that an extended claim of Lagrange is right. We show that, if all the lower directional derivatives of a locally Lipschitz function f at a point are positive, then f has a strict minimum at that point. 相似文献
943.
Transmission spectra of coupled cavity structures (CCSs) in two-dimensional (2D) photonic crystals (PCs) are investigated using a coupled mode theory, and an optical filter based on CCS is proposed. The performance of the filter is investigated using finite-difference time-domain (FDTD) method, and the results show that within a very short coupling distance of about 3λ, where λ is the wavelength of signal in vacuum, the incident signals with different frequencies are separated into different channels with a contrast ratio of 20 dB. The advantages of this kind of filter are small size and easily tunable operation frequencies. 相似文献
944.
945.
946.
The recently proposed quantum control method called self‐fulfilling prophesy is investigated in multi‐level cases, based on a sequence of measurement‐feedback operations. The feedback operation is elaborately designed with respect to the eigenstates of the density matrix of the target state and its post‐measurement state. This design procedure is suitable for the generation of any predefined coherent superpositions of multiple quantum states and elicitation of desired quantum dynamics. For the sake of clearness, arbitrarily prescribed superposition states in three‐ and four‐level systems are prepared, and quantum dynamics achieved as desired. The simulation results indicate that the scheme tolerates modest imprecisions of feedback operation and is robust against sudden perturbations. Thus, the scheme enables new insight on quantum manipulations in a variety of multi‐level systems to be achieved. 相似文献
947.
Lulu Wang Minjie Liu Meifen Jiang Li Wan Weijian Li Prof. Dang Cheng Prof. Fener Chen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(45):e202201420
Diclofenac sodium is a widely used nonsteroidal anti-inflammatory drug (NSAID) as over-the-counter (OTC) medication for the treatment of inflammatory diseases. Herein, the development of an intensified six-step continuous flow synthesis of diclofenac sodium from commercially available aniline and chloroacetic acid is described. A challenging and unprecedented etherification/Smiles rearrangement cascade of 2-chloro-N-phenylacetamide and 2,6-dichlorophenol into hydroxyacetyldiphenylamine operated with the precise control of reaction conditions in continuous flow was realized as the key step in this multistep synthetic chemistry. The undesired amide hydrolysis in Smiles rearrangement was addressed and the extra installation of N-chloroacetyl group in current industrial batch mode was avoided. Diclofenac sodium was obtained in 63 % isolated yield with an average yield of above 90 % for each step in a total residence time of 205 min. 相似文献
948.
949.
论文针对钢铁企业炼钢工序具有高温、高能耗、复杂工况的实际特征,从中提炼出生产批调度问题,其工件根据其实际工艺属性可分为多个簇,基于给定的工件簇,决策工件的分批和调度情况,综合考虑工件之间的切换费用,以及工件提前、拖期所导致的惩罚,使得总的生产成本期望最小化,从而降低生产成本;针对该问题,考虑工件的处理时间、工件的加工属性具有不确定性,基于仿真优化思想,建立数学模型,并基于大数定理,对模型目标函数进行近似;提出基于样本近似方法的求解框架,通过随机抽样的方法获得不同规模的样本,针对不同规模的样本,提出Filter & Fan算法对问题进行求解;最后,通过基于实际数据的计算实验验证所提算法的有效性。 相似文献
950.
《Indagationes Mathematicae》2019,30(6):1006-1022
In connection with the theory of hypercyclicity of bounded linear operators and strongly continuous semigroups of operators on Banach spaces, we make several observations about the following three topics – (i) special types of orbits, (ii) the role of large subsets of , (iii) various spectral conditions – and thereby highlight some nuances of the theory. 相似文献