检索结果-南通市图书馆

Perturbation of Spectra for a Class of 2×2 Operator Matrices

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2012年第4期28卷 711-720页

作者： ALATANCANG guo-lin hou guo-jun HAI School of Mathematical Sciences Inner Mongolia University

In this paper, we study the perturbation of spectra for 2 ×2 operator matrices such as Mx ={A0 XB） AC and Mz = （Az CB） on the Hilbert space H K and the sets……

关键词： operator matrices point spectrum residual spectrum continuous spectrum perturbation ofspectrum

On Invertible Nonnegative Hamiltonian Operator Matrices

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2014年第10期30卷 1763-1774页

作者： guo Hai JIN guo lin hou Alatancang CHEN De Yu WU School of Mathematical Sciences Inner Mongolia University

Some new characterizations of nonnegative Hamiltonian operator matrices are given. Several necessary and sufficient conditions for an unbounded nonnegative Hamiltonian operator to be invertible are obtained, so that the main results in the previously published papers are corollaries of the new theorems. Most of all we want to stress the method of proof. It is based on the connections between Pauli operator matrices and nonnegative Hamiltonian matrices.

关键词： Hamiltonian operators invertibility nonnegative symplectic elasticity

An Improved Method for Approximating the Infinite-Horizon Value Function of the Discrete-Time Switched LQR Problem

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2024年第1期37卷 22-39页

作者： hou Tan LI Yuanlong lin Zongli Department of Automation Shanghai Jiao Tong UniversityShanghai 200240China Key Laboratory of System Control and Information Processing Ministry of Education of ChinaShanghai 200240China Shanghai Engineering Research Center of Intelligent Control and Management Shanghai 200240China Charles L.Brown Department of Electrical and Computer Engineering University of VirginiaCharlottesvilleVA 22904-4743USA

This paper considers the problem of approximating the infinite-horizon value function of the discrete-time switched LQR *** particular,the authors propose a new value iteration method to generate a sequence of monotonically decreasing functions that converges exponentially to the value *** method facilitates us to use coarse approximations resulting from faster but less accurate algorithms for further value iteration,and thus,the proposed approach is capable of achieving a better approximation for a given computation time compared with the existing *** numerical examples are presented in this paper to illustrate the effectiveness of the proposed method.

关键词： Optimal control switched linear systems switched LQR problem.

A molecular insight into coke formation process of vacuum residue in thermal cracking reaction

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2024年第3期21卷 2130-2138页

作者： Ji-Guang Li Xin guo Huan-Di hou Heavy Oil Processing Department Sinopec Research Institute of Petroleum Processing Co.LtdBeijing100083China

Understanding the coking behaviors has been considered to be really essential for developing better vacuum residue processing technologies.A battery of thermal cracking tests of typical vacuum residue at 410℃ with various reaction time were performed to evaluate the coke formation *** total yields of ideal components including naphtha,atmospheric gas oil(AGO)and vacuum gas oil(VGO)of thermal cracking reactions increased from 10.89%to 40.81%,and the conversion ratios increased from8.05%to 43.33%with increasing the reaction time from 10 to 70 *** asphaltene content increased from 12.14%to a maximum of 22.39%and then decreased,and this maximum of asphaltene content occurred at the end of the coking induction *** asphaltenes during the coking induction period,at the end and after coking induction period of those tested thermal cracking reactions were characterized to disclose the structure changing rules for coke formation process,and the coke formation pathways were discussed to reveal the coke formation process at molecular level.

关键词： Vacuum residue Thermal cracking Asphaltene Coking induction period Sulfur Nitrogen

Structure-guided isolation of anti-neuroinflammatory sesquiterpene coumarins from Ferula sinkiangensis

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Natural Medicines 2024年第7期22卷 643-653页

作者： DANG Wen guo Tingting Zhou Di MENG Qingqi FANG Mingxia CHEN Gang lin Bin hou Yue LI Ning School of Traditional Chinese Materia Medica Key Laboratory of Innovative Traditional Chinese Medicine for Major Chronic Diseases of Liaoning ProvinceKey Laboratory for TCM Material Basis Study and Innovative Drug Development of Shenyang CityShenyang Pharmaceutical UniversityShenyang 110016China College of Life and Health Sciences Northeastern UniversityShenyang 110004China School of Pharmaceutical Engineering Shenyang Pharmaceutical UniversityShenyang 110016China

The resin of Ferula sinkiangensis has been traditionally utilized for treating gastrointestinal disorders,inflammation,tumors,various cancers,and alopecia *** primary bioactive constituents,sesquiterpene coumarins,have demonstrated notable therapeutic potential against *** this study,a structure-guided fractionation method was used to isolate nine novel sesquiterpene coumarins from the resin of *** compounds were characterized and structurally elucidated using comprehensive physicochemical and spectroscopic techniques,including calculated electronic circular dichroism(ECD).Anti-neuroinflammatory assays revealed that compounds 2,3,and 6 significantly inhibited nitric oxide(NO)production in lipopolysaccharide(LPS)-stimulated BV2 microglial cells,with IC_(50)values ranging from 1.63 to 12.25μmol·L^(−1).

关键词： Ferula sinkiangensis Sesquiterpene coumarins Structure elucidation Anti-neuroinflammatory activity

Spatiotemporal variation and freeze-thaw asymmetry of Arctic sea ice in multiple dimensions during 1979 to 2020

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2024年第3期43卷 102-114页

作者： Yu guo Xiaoli Wang He Xu Xiyong hou CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation Yantai Institute of Coastal Zone ResearchChinese Academy of SciencesYantai 264003China Shandong Key Laboratory of Coastal Environmental Processes Yantai 264003China University of Chinese Academy of Sciences Beijing 100049China

Arctic sea ice is broadly regarded as an indicator and amplifier of global climate *** rapid changes in Arctic sea ice have been widely ***,the spatiotemporal changes in the horizontal and vertical dimensions of Arctic sea ice and its asymmetry during the melt and freeze seasons are rarely quantified simultaneously based on multiple sources of the same long time *** this study,the spatiotemporal variation and freeze-thaw asymmetry of Arctic sea ice were investigated from both the horizontal and vertical dimensions during 1979–2020 based on remote sensing and assimilation *** results indicated that Arctic sea ice was declining at a remarkably high rate of–5.4×10^(4) km^(2)/a in sea ice area(SIA)and–2.2 cm/a in sea ice thickness(SIT)during 1979 to 2020,and the reduction of SIA and SIT was the largest in summer and the smallest in ***,compared with other sub-regions,SIA showed a sharper declining trend in the Barents Sea,Kara Sea,and East Siberian Sea,while SIT presented a larger downward trend in the northern Canadian Archipelago,northern Greenland,and the East Siberian *** to the seasonal trend of sea ice on sub-region scale,the reduction rate of SIA exhibited an apparent spatial heterogeneity among seasons,especially in summer and winter,i.e.,the sub-regions linked to the open ocean exhibited a higher decline rate in winter;however,the other sub-regions blocked by the coastlines presented a greater decline rate in *** SIT,the sub-regions such as the Beaufort Sea,East Siberian Sea,Chukchi Sea,Central Arctic,and Canadian Archipelago always showed a higher downward rate in all ***,a striking freeze-thaw asymmetry of Arctic sea ice was also *** sea ice changes in different dimensions,sea ice over most regions in the Arctic showed an early retreat and rapid advance in the horizontal dimension but late melting and gradual freezing in the vertical *** amount of sea ice me

关键词： Arctic sea ice sea ice area sea ice thickness spatiotemporal variation freeze-thaw asymmetry

Torque effect on vibration behavior of high-speed train gearbox under internal and external excitations

在线全文

学校读者我要写书评

暂无评论

Railway Engineering Science 2024年第2期32卷 229-243页

作者： Yue Zhou Xi Wang Hongbo Que Rubing guo Xinhai lin Siqin Jin Chengpan Wu Yu hou School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China CRRC Qishuyan Institute Co. Ltd.No.258Wuyi RoadQishuyanChangzhou 213011China Frontiers Science Center for Smart High-Speed Railway System Beijing Jiaotong UniversityBeijing 100044China

The high-speed train transmission system,experiencing both the internal excitation originating from gear meshing and the external excitation originating from the wheel-rail interaction,exhibits complex dynamic behavior in the actual service *** paper focuses on the gearbox in the high-speed train to carry out the bench test,in which various operat-ing conditions(torques and rotation speeds)were set up and the excitation condition covering both internal and external was *** responses on multiple positions of the gearbox were acquired in the test and the vibration behavior of the gearbox was ***,a stochastic excitation modal test was also carried out on the test bench under different torques,and the modal parameter of the gearbox was ***,the sweep frequency response of the gearbox under gear meshing excitation was analyzed through dynamic *** results showed that the torque has an attenuating effect on the amplitude of gear meshing frequency on the gearbox,and the effect of external excitation on the gearbox vibration cannot be ignored,especially under the rated operating *** was also found that the torque affects the modal param-eter of the gearbox *** torque has a great effect on both the gear meshing stiffness and the bearing stiffness in the transmission system,which is the inherent reason for the changed modal characteristics observed in the modal test and affects the vibration behavior of the gearbox consequently.

关键词： High-speed train Gearbox Bench test Vibration behavior Modal identification

Spatiotemporal transformable nano-assembly for on-demand drug delivery to enhance anti-tumor immunotherapy

在线全文

学校读者我要写书评

暂无评论

Asian Journal of Pharmaceutical Sciences 2024年第1期19卷 103-118页

作者： Chenglin Liang Ge Zhang linlin guo Xinyi Ding Heng Yang Hongling Zhang Zhenzhong Zhang lin hou School of Pharmaceutical Sciences Key Laboratory of Targeting Therapy and Diagnosis for Critical DiseasesZhengzhou UniversityZhengzhou 450001China

Induction of tumor cell senescence has become a promising strategy for anti-tumor immunotherapy,but fibrotic matrix severely blocks senescence inducers penetration and immune cells ***,we designed a cancer-associated fibroblasts(CAFs)triggered structure-transformable nano-assembly(HSD-P@V),which can directionally deliver valsartan(Val,CAFs regulator)and doxorubicin(DOX,senescence inducer)to the specific *** detail,DOX is conjugated with hyaluronic acid(HA)via diselenide bonds(Se-Se)to form HSD micelles,while CAFs-sensitive peptide is grafted onto the HSD to form a hydrophilic polymer,which is coated on Val nanocrystals(VNs)surface for improving the stability and achieving responsive *** arriving at tumor microenvironment and touching CAFs,HSD-P@V disintegrates into VNs and HSD micelles due to sensitive peptide *** can degrade the extracellularmatrix,leading to the enhanced penetration of *** targets tumor cells,releases DOX to induce senescence,and recruits effector immune ***,senescent cells are cleared by the recruited immune cells to finish the integrated anti-tumor *** vitro and in vivo results show that the nanoassembly remarkably inhibits tumor growth as well as lungmetastasis,and extends tumorbearing mice *** work provides a promising paradigm of programmed delivering multi-site nanomedicine for cancer immunotherapy.

关键词： Cells senescence Tumor stroma Structure transformable Programmed delivery Anti-tumor immunotherapy

Bald Eagle Search Optimization Algorithm Combined with Spherical Random Shrinkage Mechanism and Its Application

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2024年第1期21卷 572-605页

作者： Wenyan guo Zhuolin hou Fang Dai Xiaoxia Wang Yufan Qiang Department of Applied Mathematics School of ScienceXi'an University of TechnologyXian 710054ShaanxiChina

Over the last two decades,stochastic optimization algorithms have proved to be a very promising approach to solving a variety of complex optimization *** eagle search optimization(BES)as a new stochastic optimization algorithm with fast convergence speed has the ability of prominent optimization and the defect of collapsing in the local *** avoid BES collapse at local optima,inspired by the fact that the volume of the sphere is the largest when the surface area is certain,an improved bald eagle search optimization algorithm(INMBES)integrating the random shrinkage mechanism of the sphere is ***,the INMBES embeds spherical coordinates to design a more accurate parameter update method to modify the coverage and dispersion of the ***,the population splits into elite and non-elite groups and the Bernoulli chaos is applied to elite group to tap around potential solutions of the *** non-elite group is redistributed again and the Nelder-Mead simplex strategy is applied to each group to accelerate the evolution of the worst individual and the convergence process of the *** results of Friedman and Wilcoxon rank sum tests of CEC2017 in 10,30,50,and 100 dimensions numerical optimization confirm that the INMBES has superior performance in convergence accuracy and avoiding falling into local optimization compared with other potential improved algorithms but inferior to the champion algorithm and ranking *** three engineering constraint optimization problems and 26 real world problems and the problem of extracting the best feature subset by encapsulated feature selection method verify that the INMBES’s performance ranks first and has achieved satisfactory accuracy in solving practical problems.

关键词： Bald eagle search optimization algorithm Spherical coordinates Chaotic variation Simplex method Encapsulated feature selection