检索结果-南通市图书馆

Journal of Systems Engineering and Electronics 2023年第4期34卷 894-905页

作者： CHEN Siyu WANG yong cao Rui School of Electronics and Information Engineering Harbin Institute of TechnologyHarbin 150001China

Ultrahigh resolution synthetic aperture radar(SAR)imaging for ship targets is significant in SAR imaging,but it suffers from high frequency vibration of the platform,which will induce defocus into SAR imaging *** this paper,a novel compensation method based on the sinusoidal frequency modulation Fourier-Bessel transform(SFMFBT)is proposed,it can estimate the vibration errors,and the phase shift ambiguity can be avoided via extracting the time frequency ridge *** constructing the corresponding compensation function and combined with the inverse SAR(ISAR)technique,well-focused imaging results can be *** simulation imaging results of ship targets demonstrate the validity of the proposed approach.

关键词： synthetic aperture radar(SAR) high frequency vibration compensation sinusoidal frequency modulation FourierBessel transform(SFMFBT)

On the Empty Essential Spectrum for Markov Processes in Dimension One

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2006年第3期22卷 807-812页

作者： yong hua MAO Department of Mathematics Beijing Normal University

This paper gives characterizations for diffusion processes on the line and birth-death processes whose generators admit the empty essential spectra. Some equivalent conditions for empty essential spectra for general M... 详细信息

关键词： Markov generator Essential spectrum Compact embedding Hardy-type inequality

On Supercontractivity for Markov Semigroups

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2007年第5期23卷 905-914页

作者： yong hua MAO School of Mathematical Science Beijing Normal University Beijing 100875 P. R. China

In this paper, we study the supercontractivity for Maxkov semigroups and obtain some sufficient and necessary conditions; especially explicit formulae are obtained for birth-death process and diffusion on the line. Sufficient conditions and necessary conditions in terms of isoperimetric inequalities are also presented. Moreover, we prove that the supercontractivity is equivalent to the compact embedding of Sobolev space into an Orlicz space.

关键词： Markov semigroup logarithmic Sobolev inequality supercontractivity compact embedding

L^P-Poincaré Inequality for General Symmetric Forms

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2009年第12期25卷 2055-2064页

作者： yong hua MAO School of Mathematical Science LMCS Ministing of Education Beijing Normal University Beijing 100875 P. R. China

Lp Poincare inequalities for general symmetric forms are established by new Cheeger＇s isoperimetric constants. Lp super-Poincare inequalities are introduced to describe the equivalent conditions for the Lp compact embedding, and the criteria via the new Cheeger＇s constants for those inequalities are presented. Finally, the concentration or the volume growth of measures for these inequalities are studied.

关键词： Lp Poincare inequality symmetric form isoperimetric constant compact embedding concentration

Recent advances and perspective on the synthesis and photocatalytic application of metal halide perovskite nanocrystals

在线全文

学校读者我要写书评

暂无评论

Nano Research 2021年第11期14卷 3773-3794页

作者： yong Xu Muhan cao Shaoming huang Guangzhou Key Laboratory of Low-Dimensional Materials and Energy Storage Devices Collaborative Innovation Center of Advanced Energy MaterialsSchool of Materials and EnergyGuangdong University of TechnologyGuangzhou510006China Institute of Functional Nano&Soft Materials(FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials and DevicesSoochow UniversitySuzhou215123China

Metal halide perovskite nanocrystals have attracted great attention of researchers due to their unique optoelectronic properties such as high photoluminescence quantum yield (PLQY), narrow full width at half-maximum (FWHM), long exciton diffusion length and high carrier mobility, which have been widely used in diverse fields including solar cells, photodetectors, light-emitting diodes, and lasers. Very recently, metal halide perovskites have emerged as a new class of materials in photocatalysis due to their promising photocatalytic performance. In this review, we summarize the recent advances on synthesis, modification and functionalization, with a specific focus on the photocatalytic application of metal halide perovskite nanocrystals. Finally, a brief outlook is proposed to point out the challenges in this emerging area. The goal of this view is to introduce the photocatalytic application of the metal halide perovskites and motivate researchers from different fields to explore more potentials in catalysis.

关键词： metal halide perovskite nanocrystals synthesis modification functionalization photocatalytic application

S空位及非金属掺杂单层Bi_(2)S_(2)Se的第一性原理研究

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

原子与分子物理学报 2025年第1期42卷 127-134页

作者：张建华王敏陈畅曹倩徐银湖北大学资源环境学院武汉430062

Bi_(2)S_(2)Se是一种新兴的具有优异光电性能的材料,因此受到了广泛的关注.本研究采用第一性原理方法和开源程序,研究了本征单层Bi_(2)S_(2)Se以及掺杂非金属元素X(X=P,Cl,Br和I)和S空位的体系的电子结构和光学特性.计算结果表明,改性... 详细信息

Bi_(2)S_(2)Se是一种新兴的具有优异光电性能的材料,因此受到了广泛的关注.本研究采用第一性原理方法和开源程序,研究了本征单层Bi_(2)S_(2)Se以及掺杂非金属元素X(X=P,Cl,Br和I)和S空位的体系的电子结构和光学特性.计算结果表明,改性后出现了晶格缺陷.含S空位和P、Cl、Br掺杂体系的带隙减少,而I掺杂体系的带隙增加.同时,含S空位和Cl、Br、I掺杂体系的费米能级穿过导带底,而P掺杂体系的费米能级穿过价带顶.所有改性体系在费米能级附近都出现了缺陷能级或杂质能级,表现出较高的可见光吸收能力和散射能力,改性体系的对可见光的吸收能力和散射能力有所增加.

关键词： Bi_(2)S_(2)Se 掺杂电子结构光学性质第一性原理

Gas sensor array based on carbon-based thin-film transistor for selective detection of indoor harmful gases

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第9期43卷 4401-4411页

作者： Can Liu Yu Sun Jia-Yi Guo Xiu-Lei Li Lu Tao Jin-yong Hu Jue-Xian cao Ping-hua Tang yong Zhang School of Electrical and Information Engineering Hunan Institute of EngineeringXiangtan 411104China Physics and Optoelectronics&Hunan Institute of Advanced Sensing and Information Technology Xiangtan UniversityXiangtan 411105China

The identification of indoor harmful gases is imperative due to their significant threats to human health and *** achieve accurate identification,an effective strategy of constructing a sensor array combined with the pattern recognition algorithm is ***-based thin-film transistors are selected as the sensor array unit,with semiconductor carbon nanotubes(CNTs)within the TFT channels modified with different metals(Au,Cu and Ti)for selective responses to NH_(3),H_(2)S and HCHO,*** accurate gas species identification,an identification mode that combines linear discriminant analysis algorithms and logistic regression classifier is *** test results demonstrate that by preprocessing the sensor array’s sensing data with the LDA algorithm and subsequently employing the LR classifier for identification,a 100%recognition rate can be achieved for three target gases(NH3,H2S and HCHO).This work provides significant guidance for future applications of chip-level gas sensors in the realms of the Internet of Things and Artificial Intelligence.

关键词： Carbon-based thin-film transistors Gas sensor arrays Semiconductor carbon nanotubes Multi-gas detection Linear discriminant analysis

A new three-dimensional Hoek-Brown strength criterion

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2012年第2期28卷 393-406页

作者： hua Jiang yong-Li Xie Key Laboratory for Bridgeand Tunnel of Shaanxi Province Chang'an University710064 Xi'anChina

The Hoek-Brown （HB） strength criterion has been widely applied to the estimation of strength of intact rock and rock mass, while evolving ever since. However, negligence of the effect of the intermediate principal stress still remains in the criterion＇s latest version. At the same time, several three-dimensional （3D） HB strength, which can takes into account the influence of the intermediate principal stress, have already been proposed, among which the 3D HB criterion proposed by Zhang and Zhu seems to be the most reasonable one. However, the Zhang 3D HB criterion may have problems with some stress path close to triaxial extension state because of the non-convexity characteristic of its failure surface. In this paper, a new 3D HB strength criterion is presented based on a generalized form of the HB criterion, which also considers the effect of the intermediate principal stress and inherits all the merits of the original version of the HB criterion. In addition, this new criterion can remedy to some extent the shortcomings observed in the Zhang 3D HB criterion. Polyaxial tests for five different rocks from pub- lished literatures are used for evaluating this new criterion and comparing it with the Zhang 3D HB criterion. The re- sults show that this new criterion may over-predict or under- predict the polyaxial strength of rocks but the errors are rela- tively small, and similar results are also found for the Zhang 3D HB criterion, which one is better depends on the type of the rock under estimation.

关键词： Hoek-Brown criterion Rock strength Merid-ian plane Octahedral plane

Mesomechanics coal experiment and an elastic-brittle damage model based on texture features

在线全文

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2018年第4期28卷 634-642页

作者： Sun Chuanmeng cao Shugang Li yong School of Electrical and Control Engineering North University of ChinaTaiyuan 030051China National Key Laboratory of Electronic Measurement Technology North University of ChinaTaiyuan 030051China State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing UniversityChongqing 400044China College of Resources and Environmental Science Chongqi ng UniversityChongqing 400044China

To accurately describe damage within coal, digital image processing technology was used to determine texture parameters and obtain quantitative information related to coal meso-cracks. The relationship between damage and mesoscopic information for coal under compression was then analysed. The shape and distribution of damage were comprehensively considered in a defined damage variable, which was based on the texture characteristic. An elastic-brittle damage model based on the mesostructure information of coal was established. As a result, the damage model can appropriately and reliably replicate the processes of initiation, expansion, cut-through and eventual destruction of microscopic damage to coal under compression. After comparison, it was proved that the predicted overall stress-strain response of the model was comparable to the experimental result.

关键词： Mesomechanics experiment Image processing Texture feature Damage variable Damage model

提取方式对微拟球藻蛋白理化性质和功能特性的影响

在线全文

学校读者我要写书评

暂无评论

食品工业科技 2025年第1期46卷 87-96页

作者：黄素艳曹荣刘楠孙永周德庆王珊珊上海海洋大学食品学院上海201306 中国水产科学研究院黄海水产研究所山东青岛266071

以微拟球藻粉为原料,分别采用冻融盐析法、酶提辅助法和碱提酸沉法制备冻融蛋白(Nannochloropsis freeze-thawed extraction protein,NFP)、酶提蛋白(Nannochloropsis enzyme-assisted extraction protein,NEP)和碱提蛋白(Nannochloropsis alkali extraction protein,NAP),并对其理化性质和功能特性进行对比分析。结果表明,碱提酸沉法的提取率为18.70%±0.50%,显著高于其他两种提取方式(P<0.05)。NFP、NEP与NAP中均含有多种人体必需氨基酸,分别占总氨基酸含量的38.75%、38.16%和37.88%;紫外吸收光谱显示三种提取蛋白在200~220 nm处有较强的吸光值;傅里叶变换红外光谱表明三种蛋白均具有典型的蛋白吸收峰,但二级结构发生变化,碱提处理使NAP中β-转角相对含量降低至19.62%±1.48%,β-折叠相对含量增加至32.90%±1.55%;与NEP和NFP相比,NAP的游离巯基含量和Zeta电位绝对值显著上升,粒径显著下降(P<0.05);扫描电镜显示不同提取方式下蛋白的显微结构有差异。功能特性分析显示三种蛋白的溶解性、起泡性及起泡稳定性随pH的变化趋势相似;相比NEP和NAP,NFP具有更好的功能特性。该研究结果为微藻蛋白资源在食品领域的开发利用提供了一定的理论依据。

关键词：微拟球藻蛋白质碱提酸沉理化性质功能特性

维普期刊数据库博看期刊