检索结果-南通市图书馆

Image denoising and deblurring: non-convex regularization, inverse diffusion and shock filter

在线全文

学校读者我要写书评

暂无评论

science china(Information sciences) 2011年第6期54卷 1184-1198页

作者： FU ShuJun 1,2.3 , ZHANG CaiMing 2.& TAI XueCheng 3,4 1 school of Mathematics, Shandong university, Jinan 2.0100,{2. 2.school of Computer science and technology, Shandong university, Jinan 2.0101,{2. 3 school of physical and Mathematical sciences, Nanyang Technological university, Singapore 639798, Singapore 4 Department of Mathematics, university of Bergen, Bergen 5008, Norway 1. school of Mathematics Shandong University Jinan 250100 China2. School of Computer Science and Technology Shandong University Jinan 250101 China3. School of Physical and Mathematical Sciences Nanyang Technological University Singapore 639798 Singapore4. Department of Mathematics University of Bergen Bergen 5008 Norway

A large number of applications in image processing and computer vision depend on image quality. In this paper, main concerns are image denoising and deblurring simultaneously in a restoration task by three types of methodologies: non-convex regularization, inverse diffusion and shock filter. We discuss their relations in the context of image deblurring: the inverse diffusion implied by the non-convex regularization, and the superior ability of deblurring edge of the shock filter to that of the inverse diffusion, both in 1D and 2. cases. Finally, we propose a region-based adaptive anisotropic diffusion with shock filter method, which shows advantages of deblurring edges, denoising and smoothing contours in experiments, compared with some related methods. Therein an idea of "divide and rule" is introduced.

关键词： image denoising image deblurring non-convex regularization inverse diffusion shock filter adaptive anisotropic diffusion

Threshold quantum secure direct communication without entanglement

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2008年第2期51卷 176-183页

作者： YANG YuGuang1,3 & WEN QiaoYan2.1 College of Computer science and technology, Beijing {2. of technology, Beijing 10002., china 2.school of science, Beijing {2. of Posts and Telecommunications, Beijing 100876, china 3 State Key Laboratory of Information Security (Graduate school of Chinese Academy of sciences), Beijing 100049, china 1. College of Computer science and technology Beijing University of Technology Beijing 100022 China 3. State Key Laboratory of Information Security (Graduate school of Chinese Academy of sciences) Beijing 100049 China 2. school of science Beijing University of Posts and Telecommunications Beijing 100876 China

For the first time, a threshold quantum secure direct communication (TQSDC) scheme is presented. Similar to the classical Shamir's secret sharing scheme, the sender makes n shares, S1, …, Sn of secret key K and each receiver keeps a share secretly. If the sender wants to send a secret message M to the receivers, he en-codes the information of K and M on a single photon sequence and sends it to one of the receivers. According to the secret shares, the t receivers sequentially per-form the corresponding unitary operations on the single photon sequence and ob-tain the secret message M. The shared shares may be reusable if it can be judged that there is no eavesdropper in line. We discuss that our protocol is feasible with current technology.

关键词： quantum secure direct communication threshold secure direct communication quantum secret sharing

Spinning Deformation Criteria of Thin-walled Tubular Part with Longitudinal Inner Ribs

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan university of technology(Materials {2.) 2006年第4期21卷 169-172页

作者：江树勇 Engineering Training Center Harbin Engineering University Harbin 150001China

As a successive and local plastic deformation process, backward ball spinning was applied for the purpose of prodacing thin-walled tubular parts with longitudinal inner ribs. According to the local plastic deformation theoo,, the application of yield criterion to the spinning process and the influence of the radial spinning force component on the formability of inner ribs were analyzed. Based on yield criterion and plastic mechanics, the stable flow rule of metal material and forming criteria of the inner ribs were obtained aad conformed to the experimental results so as to contribute greatly to improving the ball spinning process and optimizing the process variables, such as the diameter of ball, the reduction in a pass and the wall thickness of tubular blank, which have a significant influenee on the formability of the inner ribs. The knowledge of the influence of the process variables such as the diameter of ball, the reduction in a pass and the wall thickness of tubular blank on the spinning process is essential to preventing the quality defects of the spun parts and obtaining the desired spun parts.

关键词： ball spinning power spinning spinning force criterion

Numerical simulations and experimental investigations on transverse effects of two-wave mixing in a photovoltaic photorefractive crystal

在线全文

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2010年第5期53卷 856-863页

作者： CAI Xin1,2.LIU JinSong1 & WANG ShengLie1 1 Wuhan National Laboratory for Optoelectronics,school of Optoelectronic science and Engineering,Huazhong {2. of science and technology,Wuhan 430074,china 2.school of science,Wuhan {2. of technology,Wuhan 430070,china 1. Wuhan National Laboratory for Optoelectronics School of Optoelectronic Science and Engineering Huazhong University of Science and Technology Wuhan 430074 China2. School of Science Wuhan University of Technology Wuhan 430070 China

The transverse effects of two Gauss waves mixing in a photovoltaic photorefractive crystal,i.e.,the dynamical evolutions of signal beam with different parameters,are traced numerically and *** the one-dimensional numerical simulations and two-dimensional experimental investigations show that the self-focusing effect of signal beam becomes more obvious as the intensity of pump beam and the angle between the signal and pump beams *** accordance with these results,the state of two Gaussian waves mixing is controllable.

关键词： numerical simulation experimental investigation two-wave mixing transverse effects Gaussian distribution

Chemical Extraction Preparation of Delithiated Cathode Materials of Li-ion Battery

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan university of technology(Materials {2.) 2009年第6期24卷 863-866页

作者：闫时建 school of Materials science and Engineering Taiyuan University of Science and Technology

A method of conventional chemical reaction to prepare delithiated cathode materials of Li-ion battery was introduced. The cathode material of Li-ion battery was mixed with oxidizing agent Na2.2.8 in water solution, and the solution was stirred continuously to make the chemical reaction proceed sufficiently, then the reaction product was filtered and finally the insoluble delithiated cathode material was obtained. A series of tests were conducted to verify the composition, crystal structure and electrochemical property of the delithiated cathode materials were all desirable. This method overcomes the shortcomings of battery charging preparation and chemical extraction preparation employing other oxidizing agents.

关键词： chemical extraction delithiated cathode material Li-ion battery

Production of O' -sialon-SiC Composites by Carbon Reduction-Nitridation

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 1998年第1期12卷 26-30页

作者： Haijun Zhang Wenchao Li Xiangcong Zhong (Applied science school, {2. of science and technology Beijing, Beijing 1 0008 3, china) Applied science school University of Science and Technology Beijing Beijing 100083 China

The effect of temperature, soak times, carbon and addition on composites was discussed in the process ofsynthesizing O'-sialon-SiC by carbonthermal reduction-nitration from nature kaolin. It showed that the fracturestrength (MOR) of composites sintered under certain conditions can be up to 140MPa at room temperature. Thetarget parameter optima regions with good mechanical properties of this material were also indicated by usingcomputer pattern recognition program.

关键词： O'-sialon-SiC compostites carbonthermal reduction-nitration pattern recognition program

Sensing characterization of Sn/In/Ti nanocomplex oxides for CO, CH_4 and NO_2

在线全文

学校读者我要写书评

暂无评论

science china(Technological sciences) 2007年第1期50卷 18-26页

作者： BAI ShouLi1, TONG ZhangFa2. LI DianQing1, HUANG XiaoWei3, LUO RuiXian1 & CHEN AiFan1 1 State Key Laboratory of Chemical Resource Engineering, Beijing university of Chemical technology, Beijing 10002.,{2. 2.school of Chemistry and Chemical Engineering, guangxi university, nanning 530004,{2. 3 College of Biochemical Engineering, Beijing Union university, Beijing 10002.,{2. 1. State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical Technology Beijing 100029 China 2. school of Chemistry and Chemical Engineering Guangxi University Nanning 530004 China 3. College of Biochemical Engineering Beijing Union University Beijing 100023 China

The nanocomplex oxides of Sn-In and Sn-In-Ti were prepared by controlled co-precipitation method as sensing materials of semiconductor gas sensors for detection of CO, CH4 and NO2. Through manipulating the Sn/In cation ratio, metal salt total concentration, precipitation pH value and aging time, the nanocrystalline powders were successfully derived with chemical homogeneity and superior thermal stability, compared with the single component oxides. The particle size and morphology, surface area, and thermal and phase stabilities were characterized using TEM, TG-DTA, BET and XRD. The sensing tests showed that the Sn-In com-posites exhibit high sensitivity and selectivity for CO and NO2. The introduction of TiO2.enhanced CH4 sensitivity and selectivity, particularly, additives of Pd and Al2.3 as a dopant and surface modification greatly enhanced the sensing properties. The sensitivity depended on the composition of composites, calcination temperature and operating temperature. The optimal values were (2.%In2.3- 75%SnO2.-2.%TiO2.for ternary composite, 600 and 300℃, respectively. Temperature-programmed de-sorption (TPD) studies were employed to explain the gas adsorption behavior dis-played by the surface of nanocomposites and X-ray photoelectron spectroscopic (XPS) analysis was used to confirm the electronic interactions existing between oxide components. The sensing mechanism of the nanocomposites was attributed to chemical and electronic synergistic effects.

关键词： SnO2.In2.3-TiO2 nanocomposites CO NO2 CH4 gas sensing

Phase transition in the Zr_(60)Al_(15)Ni_(2.) bulk metallic glass subjected to rolling at room temperature

在线全文

学校读者我要写书评

暂无评论

science china(Technological sciences) 2006年第6期49卷 655-662页

作者： YAN Zhijie1, 2. LI Jinfu1, ZHOU Yaohe1 & WU Yanqing3 1. State Key Laboratory of Metal Matrix Composites, school of Materials science and Engineering, Shanghai Jiao Tong {2., Shanghai 2.0030, china 2. school of Materials science and Engineering, Taiyuan {2. of science and technology, Taiyuan 03002., china 3. school of Environmental science and Engineering, Shanghai Jiao Tong {2., Shanghai 2.0030, china State Key Laboratory of Metal Matrix Composites School of Materials Science Engineering Shanghai Jiao Tong University Shanghai 200030 China school of Materials science Engineering Taiyuan University of Science technology Taiyuan 030024 China school of Environmental science Engineering Shanghai Jiao Tong University Shanghai 200030 China

The microstructure evolution of the Zr60Al15Ni2. metallic glass during rolling at room temperature is investigated by X-ray diffraction (XRD), differential scanning calorimetry (DSC); high-resolution transmission electron microscopy (HREM). The results show that the values of full width at half maximum (FWHM) of the XRD patterns; exothermic enthalpy ΔH of DSC plots do not monotonically change with the variation of deformation degrees . As is not large than 2.%, the values of FWHM; ΔH are lower than that of the as-cast state. When reaches 30%, the values of FWHM; ΔH become larger than that of the as-cast state, while their values begin to decrease again as reaches about 85%. These results indicate that the reversible transitions between ordered; disordered atomic configurations occur during rolling, which is further verified by the HREM images. The reversible phase transition can be explained by the competition between the diffusion controlled reordering; shear-induced disordering during rolling.

关键词： metallic glasses, plastic deformation, phase transformations, shear bands.

Effect of Preparation Methods on Mechanical Properties of PVA/HA Composite Hydrogel

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2010年第3期7卷 235-243页

作者： Dekun Zhang~1, Junjie Duan~1, Dagang Wang~2. Shirong Ge~2.1. school of Materials science and Engineering,{2. university of Mining and technology Xuzhou 2.1116, P. R.{2. 2. school of Mechanical and Electrical Engineering,{2. university of Mining and technology, Xuzhou 2.1116, P. R.{2. [a] school of Materials science Engineering China University of Mining technology Xuzhou 221116 P. R. China [b] School of Mechanical Electrical Engineering China University of Mining technology Xuzhou 221116 P. R. China

Poly(vinyl alcohol) (PVA)/hydroxyapatite (HA) composite hydrogel specimens were prepared with 15% PVA and 1%,2., 3%, 4% and 5% HA by repeated freezing-thawing. The tests of static and dynamic mechanical properties were carried out todiscuss the influence of different contents of HA and freezing-thawing cycles on the mechanical properties of PVA/HA compositehydrogel. The results of static mechanical tests showed that the PVA/HA composite hydrogel with 3% HA and ninefreezing-thawing cycles had excellent stress relaxation properties, higher relaxation ratio, lower stress equilibrium value andpresented better properties of creep and recovery. The results of dynamic mechanical test showed that the PVA/HA compositehydrogel with nine freezing-thawing cycles had higher storage modulus and loss modulus, so was the PVA/HA compositehydrogel with 3% HA.

关键词： composite hydrogel HA contents freezing-thawing cycles static properties dynamic properties