检索结果-南通市图书馆

Chinese Journal of Chemistry 1997年第1期15卷 54-59页

作者： LI, Shu-Lan LIU, De-Xin YANG, Zhao-HeDepartment of Chemistry, shandong university, jinan, {2. 2501.0, china national laboratory of crystal materials, shandong university, jinan, {2. 2501.0, china Department of Chemistry Shandong University Jinan Shandong 250100 China national laboratory of {2. materials Shandong University Jinan Shandong 250100 China [*]Department of Chemistry Shandong University Jinan Shandong 250100 China

Monoaqua salicylaldehyde-o-aminobenzoic acid Ni(Ⅱ) monohydrate (cp1) and monoaqua o-vanillin-o-aminobenzoic acid Ni(Ⅱ) monohydrate (cp2. were synthesized. The composition and structures of these two compounds were analyzed. Their thermal stability and non-isothermal kinetics were also investigated by use of TG and DTG curves. The possible reaction mechanisms in their first steps of thermal decomposition reactions were deduced by means of integral and differential methods. Thermodecomposition kinetic equations of the compounds are as follows:Cp1: da/At = A . exp(-E/RT) . 3/2.1 - a)4/3 . [1/(1 - a)1/3 -1]-1 Cp2.: da/At = A . exp(-E/RT) . (1 - a)

关键词： Schiff base compound amino acid nickel(Ⅱ) kinetics nonisothermal

Ground state and polaron and bipolaron excited states in polydiacetylene

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2006年第4期49卷 430-439页

作者： LI Yuan1, HU Guichao1, XIA Caijuan1, LIU Desheng1,2.& XIE Shijie1,2.1. School of Physics and Microelectronics, shandong university, jinan 2501.0,{2. 2. national key laboratory of crystal materials, shandong university, jinan 2501.0,{2. 1. School of Physics and Microelectronics Shandong University Jinan 250100 China 2. national key laboratory of crystal materials Shandong University Jinan 250100 China

The electronic properties of ground state and charged excited states of nondegenerate polydiacetylene were investigated by means of a tight-binding model. The parameters of the model were obtained by comparison of the experimental and other theoretical results. It was found that there is a stable dimerized structure of polydiacetylene in ground state and the doping induces the nonlinear excitations, such as polarons and bipolarons. In order to compare the stability of polaron and bipolaron, the creation energy and binding energy were separately defined. By neglecting the electron-electron Coulomb interaction, a bipolaron is more stable than two independent polarons.

关键词： dimerization, polaron, bipolaron, binding energy.

Experimental Investigation of Thermal Lensing in End-pumped Nd∶YVO4 crystal Using a New Simple Approach

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Lasers 1999年第2期8卷 8-13页

作者： LIU Junhai LU Jianren LU Junhua SHAO Zongshu JIANG Minhua (national laboratory of {2. materials, shandong university, jinan 2501.0, china) 山东大学晶体材料国家重点实验室山东济南 250100 山东大学晶体材料国家重点实验室山东济南

１ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｈｉｇｈｐｏｗｅｒｓｏｌｉｄｓｔａｔｅｌａｓｅｒｓ，ｐｕｍｐｉｎｄｕｃｅｄｔｈｅｒｍａｌｆｏｃｕｓｉｎｇｉｓｏｆｐｒｉｍａｒｙｉｍｐｏｒｔａｎｃｅｂｅｃａｕｓｅｏｆｉｔｓｓｉｇｎｉ... 详细信息

１ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｈｉｇｈｐｏｗｅｒｓｏｌｉｄｓｔａｔｅｌａｓｅｒｓ，ｐｕｍｐｉｎｄｕｃｅｄｔｈｅｒｍａｌｆｏｃｕｓｉｎｇｉｓｏｆｐｒｉｍａｒｙｉｍｐｏｒｔａｎｃｅｂｅｃａｕｓｅｏｆｉｔｓｓｉｇｎｉｆｉｃａｎｔｉｎｆｌｕｅｎｃｅｓｏ...

关键词： thermal lensing thermal focal length Nd∶YVO 4 crystal resonator stability

Efficient 15-W CW Nd:YVO4 Solid-state Laser Single-end-pumped by a Fiber-coupled Diode-laser-array

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Lasers 1999年第5期8卷 3-5页

作者： LIU Junhai LU Junhua LI Guangming SHAO Zongshu JIANG Minhua(national laboratory of {2. materials,shandong university, jinan 2501.0, china) 山东大学晶体材料国家重点实验室山东济南 250100 山东大学晶体材料国家重点实验室山东济南

A dedes-laser-array single-end-pumped CW Nd: YVO4 laser, capable of preducing max0imum TEM00 mode output power of 15 W, has been demonstrated. At the incident pumping power of 2. W, the output power of 13. 8 W was obtained, leading to an optical converson effciency of 57. 5%, and the slope efficiency of 66. 7%. It is shown that only with Nd: YVO4 crystals of low Nd3+ concentration, the laser can be operated efficiently under high pump power levels.

关键词： diode-laser-array end-pumped high-power Nd:YVO4 laser thermal lensing

Growth, structure and upconversion mechanisms of Ba_2.rCl_7 crystal

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2000年第11期45卷 981-984页

作者： HAN Jianru, ZHOU Guangyong, ZHANG Shujun, CHENG Zhenxiang & CHEN HuanchuState key laboratory of {2. materials, Institute of {2. materials of shandong university, jinan 2501.0, china Stale key laboratory of {2. materials Institute of Crystal Materials of Shandong University Jinan China

The methods to grow a novel upconversion crystal Ba2.rCI7 are reported in this note. Ba2.rCI7 material was synthesized with Er2.3, BaCI2.2.2. and NH4CI by using a so-called "direct synthesis method". High quality Ba2.rCI7 single crystals with size up to 4 mm×8 mm×15 mm were grown by using the Czochralski and the Bridgman methods. Intense yellow-green luminescence was detected when the crystal was pumped by an 803 laser diode (LD). Transmittance spectrum was measured by using HITACH U-3500 spectrophotometer at room temperature for the first time, in which one can see that the transmittance is high in the range from 350 to 1 600 nm and the cut-off wavelength of the crystal was 2.0 nm. The upconversion mechanisms were discussed.

关键词： Ba2.rCl2 single crystal growth transmittance spectra upconversion mechanisms.

Geometric and Electronic Structure of Squaric Acid from DFT Calculation

在线全文

学校读者我要写书评

暂无评论

Journal of materials Science & Technology 2004年第2期20卷 206-208页

作者： Xuyan XUE, Chunlei WANG and Weilie ZHONGSchool of Physics and Microelectronics, State key laboratory of {2. materials, shandong university, jinan 2501.0, china shandong Univ Sch Phys & Microelect State Key Lab Crystal Mat Jinan 250100 Peoples R China

The crystal and electronic structure of antiferroelectric squaric acid is studied using density functional theory method, and the exchange correlation effects are treated by the generalized approximation. In order to understand the ferroelectricity of H2.Q in the molecular plane and the antiferroelectricity in whole crystal, the density of states, charge density distribution and band structure are calculated. The result showed that O2. and C2. play important roles in the interactions between layers. The hybridizations of 02.-Hls and 02.-Hls are responsible for the tendency to ferroelectricity within each layer.

关键词： Antiferroelectricity Electronic structure Squaric acid

Electron transport properties of boron-doped capped-carbon-nanotube-based molecular junctions

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 2010年第36期55卷 4104-4107页

作者： ZHAO Peng1 & LIU DeSheng2.1 School of Science, university of jinan, jinan 2.002., china 2.School of Physics, State key laboratory of crystal materials, shandong university, jinan 2501.0, china School of Science University of Jinan Jinan 250022 China School of Physics State Key Laboratory of Crystal Materials Shandong University Jinan 250100 China

Using the Landauer formalism that combines both the non-equilibrium Green’s function and first-principles density functional theory, the electron transport properties of a one-dimensional molecular junction based on capped carbon nanotubes with boron doping at various sites are investigated. The results show that the electron transport properties are strongly dependent on the boron-doping site. Negative differential resistance behavior can be observed when boron-atom dopants are present in the tip region.

关键词： carbon nanotube doping non-equilibrium Green’s function density functional theory

Study on the cluster of floating dross before nucleating during hot-dipping process

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 Chemistry 2005年第1期48卷 83-88页

作者： WEI Yunhe1, ZHANG Changqiao1, QIN Jingyu2.& LIU Chengbu1 1. School of Chemistry and Chemical Engineering, shandong university, jinan 2501.0,{2. 2. The key laboratory of Liquid Structure and Heredity of materials of Ministry of Education, shandong university, jinan 2.0061,{2. 1. School of Chemistry and Chemical Engineering Shandong University 250100 Jinan China 2. The key laboratory of Liquid Structure and Heredity of {2. of Ministry of Education Shandong University 250061 Jinan China

During hot-dipping in molten Zn-55Al, the forming of “floating” dross is closely re- lated with the interaction between the Al and the Fe atoms. Utilizing the thita-thita X-ray diffraction and the Percus-Yevick hard sphere model, this paper investigates the structure of molten Al3Fe that is an approximant of partial melt in practical Zn-55Al alloy melt. It is found that in the melt there exist clusters that resemble the structure of intermetallic compound Al3Fe. The strong in- teraction between Al and Fe atoms is also indicated by the deficiency of the coordination number from 12.and the shrinkage of averaged atomic diameter. Based on such information, it is specu- lated that in the molten Zn-55Al, with the accumulation of Fe, Al3Fe-like clusters form with priority, then grow into dross. On the other hand, after deflating of the effective hard sphere diameter of pure Al atom and enlarging that of the pure Fe atom, the modified model can achieve reasonable fit to the experimental structure factor. Hard sphere modeling also gave a good estimation of the mass density 3.65 g/cm3 of liquid Al3Fe alloy at 1550℃. Compared with the density of 3.7 g/cm3 of Zn-55Al, the reason for dross floating is satisfactorily understood.

关键词： hot-dipping, dross, Al3Fe alloy, molten structure, P-Y model.

Dominant point detecting based non-uniform B-spline approximation for grain contour

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 90-96页

作者： ZHAO XiuYang1, YIN YanSheng1,2.& YANG Bo3 1 shandong key {2. of Engineering Ceramics, shandong university, jinan 2.0061, china 2.School of materials, Ocean university of china, Qingdao 2.6003, china 3 State key {2. of Advanced Technology for materials Synthesis and Processing, Wuhan university of Science and Technology, Wuhan 430070, china 1. shandong key {2. of Engineering Ceramics Shandong University Jinan 250061 China 2. School of materials Ocean University of China Qingdao 266003 China 3. State key laboratory of Advanced Technology for {2. Synthesis and Processing Wuhan University of Science and Technology Wuhan 430070 China

Three-dimension reconstruction from serial sections has been used in the last decade to obtain information concerning three-dimensional microstructural ge-ometry. One of the crucial steps of three-dimension reconstruction is getting compact and fairing grain contours. Based on the achievement of closed raw con-tours of ceramic composite grains by using wavelet and level set, an adaptive method is adopted for the polygonal approximation of the digitized raw contours. Instead of setting a fixed length of support region in advance, the novel method computes the suitable length of support region for each point to find the best es-timated curvature. The dominant points are identified as the points with local maximum estimated curvatures. Periodic closed B-spline approximation is used to find the most compact B-spline grain boundary contours within the given tolerance. A flexible distance selection approach is adopted to obtain the common knot vector of serial contours consisting of less knots that contain enough degrees of freedom to guarantee the existence of a B-spline curve interpolating each contour. Finally, a B-spline surface interpolating the serial contours is generated via B-spline surface skinning.

关键词： composite B-spline dominant points control points grain contour

A first-principles study of dihydroazulene as a possible optical molecular switch

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & Astronomy) 2011年第3期Mechanics & Astronomy) .卷 437-441页

作者： XIA CaiJuan1, LIU DeSheng2.3 & LIU HanChen1 1 School of Science, Xi’an Polytechnic university, Xi’an 710048, china 2.School of Physics, State {2. laboratory of crystal materials, shandong university, jinan 2501.0, china 3 Department of Physics, Jining university, Qufu 2.3155, china 1. School of Science Xi’an Polytechnic University Xi’an 710048 China2. School of Physics State Key Laboratory of Crystal Materials Shandong University Jinan 250100 China3. Department of Physics Jining University Qufu 273155 China

By applying nonequilibrium Green's function formalism combined with first-principles density functional theory, we investigate the electronic transport properties of the dihydroazulene optical molecular switch. Three kinds of adsorption sites including the hollow, bridge and top sites are studied. The two forms of this molecule, namely the open form and the closed form, can reversibly switch from each other upon photoexcitation. Their transmission spectra are remarkably distinctive. Theoretical results show that the current of the closed form is always significantly larger than that of the open form for all three adsorption sites, which promises this system as possibly one of the good candidates for optical switches due to its unique advantage, and which may have some potential applications in the future molecular circuit.

关键词： molecular switch nonequilibrium Green’s function electronic transport density functional theory