检索结果-南通市图书馆

Implementation of a multiple round quantum dense coding using nuclear magnetic resonance

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2005年第6期48卷 706-715页

作者： ZHANG Jingfu1, XIE Jingyi2. WANG Chuan1, DENG Zhiwei3. LU Zhiheng4, & LONG Guilu1,5 1. Key Laboratory For Quantum Information and Measurements of MOE, Department of physics, Tsinghua University, beijing 100084,{2. 2. Department of Materials Science and Engineering, beijing Normal University, beijing 100875, china 3. Testing and Analytical center, beijing Normal University, beijing 100875,{2. 4. Department of physics, beijing Normal University, beijing 100875, china 5. Key Laboratory For atomic and Molecular Nanosciences, Tsinghua University, beijing 100084,{2. Key Laboratory For Quantum Information and Measurements Department of Physics Tsinghua University Beijing 100084 China Department of Materials Science and Engineering Beijing Normal University Beijing 100875 China Testing and Analytical center Beijing Normal University Beijing 100875 China Department of physics Beijing Normal University Beijing 100875 China Key Laboratory for Atomic and Molecular Nanosciences Tsinghua University Beijing 100084 China

A multiple round quantum dense coding scheme based on the quantum phase estimation algorithm is proposed and implemented in a three qubit nuclear magnetic resonance (NMR) quantum computer. Using an m + 1 qubit system, Bob can transmit one of 2.+1 messages to Alice, through manipulating only one qubit and exchanging it between Alice and Bob for m rounds. The information capacity is enhanced to m + 1 bits as compared to m bits in a classical scheme. The scheme has been demonstrated in NMR system, and the experimental results show a good agreement between theory and experiment.

关键词： quantum dense coding, multiple round, nuclear magnetic resorance

Characterization of different-Al-content AlGaN/GaN heterostructures on sapphire

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1期53卷 49-53页

作者： DING GuoJian , GUO LiWei, XING ZhiGang, CHEN Yao, XU PeiQiang, JIA HaiQiang, ZHOU JunMing & CHEN Hong beijing National Laboratory of condensed {2.{3., institute of physics, Chinese Academy of Sciences, beijing 100190, china beijing National Laboratory of condensed {2.{3. Institute of Physics Chinese Academy of Sciences Beijing China

Al x Ga 1-x N/GaN high-electron-mobility transistor (HEMT) structures with Al composition ranging from x = 0.13.to 0.3. are grown on sapphire substrates by low-pressure metalorganic chemical vapor deposition (LP-MOCVD). The effects of Al content on crystal quality, surface morphology, optical and electrical characteristics of the AlGaN/GaN heterostructures have been analyzed. Although high Al-content (3.%) heterostructure exhibits a distinguished photoluminescence peak related to recombination between the two-dimensional electron gas and photoexcited holes (2.EG-h), its crystal quality and rough surface morphology are poor. 2.EG mobility increases with the Al content up to 2.% and then it apparently decreases for high Al-content (3.%) AlGaN/GaN heterostructure. The increase of sheet carrier density with the increase of Al content has been observed. A high mobility at room temperature of 2.05 cm 2./V s with a sheet carrier density of n s = 1.10 × 10 13.cm -2., for a 2.% Al-content AlGaN/GaN heterostructure has been obtained, which is approaching state-of-the-art for HEMT grown on SiC. Sheet resistance as low as 2.4 Ω/□ has also been achieved.

关键词： AlGaN Hall-effect luminescence

The unconditional stable and convergent difference methods with intrinsic parallelism for quasilinear parabolic systems

在线全文

学校读者我要写书评

暂无评论

Science china Mathematics 2004年第3期47卷 453-472页

作者： ZHOU Yulin YUAN Guangwei SHEN Longjun Laboratory of Computational physics, center of Nonlinear Studies, {2. of Applied physics and Computational Mathematics, beijing 100088, china Laboratory of Computational physics Center of Nonlinear Studies Institute of Applied Physics and Computational Mathematics Beijing China

A kind of the general finite difference schemes with intrinsic parallelism for the boundary value problem of the quasilinear parabolic system is studied without assuming heuristically that the original boundary value problem has the unique smooth vector solution. By the method of a priori estimation of the discrete solutions of the nonlinear difference systems, and the interpolation formulas of the various norms of the discrete functions and the fixed-point technique in finite dimensional Euclidean space, the existence and uniqueness of the discrete vector solutions of the nonlinear difference system with intrinsic parallelism are proved. Moreover the unconditional stability of the general finite difference schemes with intrinsic parallelism is justified in the sense of the continuous dependence of the discrete vector solution of the difference schemes on the discrete data of the original problems in the discrete W 2.(2.1) norms. Finally the convergence of the discrete vector solutions of the certain difference schemes with intrinsic parallelism to the unique generalized solution of the original quasilinear parabolic problem is proved.

关键词： difference scheme, intrinsic parallelism,quasilinear parabolic system, convergence, stability.

Pressure-induced crystallite breaking in La_(0.7)Sr_(0.3.Mn_(0.9)Fe_(0.1)O_3.nanosolids

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1998年第6期43卷 458-461页

作者： ZHENG Fanlei 1, 2. SUI Yu 1, 3. XU Dapeng 1 and SU Wenhui 1, 4 1. Department of physics, Jilin University, Changchun 13.02.,{3. 2. Changchun{2., Chinese Academy of Sciences, Changchun 13.02.,{3. 3. institute of Metal R Department of physics Jilin University Changchun Chinas Changchun institute of physics Chinese Academy of Sciences Changchun China institute of Metal Research Chinese Academy of Sciences Shenyang China International center for Materials physics Chinese Academy of Sceinces Shenyang China center for condensed {2. and Radiation{3. CCAST (World Lab.) Beijing China

In the compacting process of the La 0.7Sr 0.3.n 0.9Fe 0.1O 3.nanosolids under the pressure range of 0.0-4.5 GPa, the apparent pressure-induced crystallite breaking phenomenon in these nanosolids was observed. With increasing pressure up to 4.5 GPa, the average grain size decreases by 46% while the magnetization of nanosolids decrease by 40% and their coercive increases by 3.%. This kind of breaking has a close relation to the existence of oxygen deficiency in La 0.7Sr 0.3.n 0.9Fe 0.1O 3.nanoparticles. A simple and convenient method for preparing the bulk nanosolids with a large number of clean interfaces has been suggested.

关键词： nanosolid pressure-induced breaking high pressure.

The study of two-color excitation upconversion of Pr(0.5)Yb(3.:ZBLAN

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2期49卷 169-177页

作者： CHEN Xiaobo1 & SONG Zengfu2.1. Applied Optics beijing Area Major Laboratory, Analysis and testing center, beijing Normal University, beijing 100875, china 2. Peking University, physics School, beijing 100871, china Applied Optics beijing Area Major Laboratory Analysis and testing center Beijing Normal University Beijing China physics School Peking University Beijing China

The excited state absorption upconversion of Pr(0.5)Yb(3.:ZBLAN glass material, under two-color excitation of the 960 nm semiconductor laser and the Xe lamp light simultaneously, is reported in this article. It was found that the upconversion emission spectra of 480.1, 519.0, 601.9 and 63..8 nm coincide with the common emission spectra. Meanwhile, the upconversion-excitation spectrum has three obvious peaks under two-color excitation, and they respectively correspond to the 856.0 nm upconversion ex-citation transition [1G4(Pr3.)→1I6(Pr3.) and 1G4(Pr3.)→3.1(Pr3.)], the 789.0 nm upconver-sion excitation transition 1G4(Pr3.)→3.2.Pr3.), and the 803.7 nm upconversion excitation transition 3.6(Pr3.)→1D2.Pr3.). The upconversion excitation transition 1G4(Pr3.)→1I6(Pr3.) is strong because its oscillator strength f = 2..040×10?6 is large, which results in a large peak appearing in the upconversion excitation spectrum. That is just the new interesting two-color excitation upconversion luminescence phenomenon of Pr(0.5)Yb(3.:ZBLAN induced by one laser and one continuous normal light simultaneously.

关键词： upconversion volumetric three-dimensional display two-color excitation.

Improvement of refrigerant capacity of La_(0.67)Ca_(0.3.)MnO_(3. single crystal with a few percent Fe doping

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2009年第6期52卷 809-812页

作者： LI GuoKe, ZHANG XiangQun, KOU ZhiQi, LI QingAn, SUN Young & CHENG ZhaoHua State Key Laboratory of Magnetism, beijing National Laboratory of condensed {2.{3. and institute of physics, Chinese Academy of Sciences, beijing 100190, china State Key Laboratory of Magnetism Beijing National Laboratory of Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences Beijing China

Large low-field-induced magnetic entropy changes, ΔSM, are observed in La0.67Ca0.3.MnO3.and La0.67-Ca0.3.Mn0.96Fe0.04O3.single crystals. The peaks of ΔSM broadened asymmetrically to high temperatures under higher magnetic fields for two materials should be attributed to the first-order magnetic phase transition at Tc. A small amount of iron doping results in an increase in the refrigerant capacity of the material though the magnetic entropy change decreases. The discovery of excellent magnetocaloric features of these single crystals in the low magnetic field can provide some ideas for exploring novel magnetic refrigerants operating under permanent magnet rather than superconducting one as magnetic field source.

关键词： single crystal magnetic entropy refrigerant capacity

Synthesis of superheavy nuclei with ^(2.8)U target

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2009年第10期52卷 1482-1488页

作者： LIU ZuHua1,3.& BAO JingDong2.4 1 Key Laboratory of Beam Technology and Material Modification of Ministry of Education,beijing Normal University,beijing 100875,{2. 2.Department of {3.,beijing Normal University,beijing 100875,{2. 3.9} institute of Atomic Energy,beijing 102.13.{2. 4 center of Theoretical Nuclear {3.,National Laboratory of Heavy Ion Accelerator of Lanzhou,Lanzhou 73.000,{2. Key Laboratory of Beam Technology and Material Modification of Ministry of Education Beijing Normal University Beijing China china institute of Atomic Energy Beijing China Department of physics Beijing Normal University Beijing China center of Theoretical Nuclear physics National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou China

The production of superheavy nuclei with Z=108-116 via hot fusion reactions of the neutron-rich projectiles with 2.8U target is systematically *** results show that the production cross sections of superheavy nuclei do not decrease monotonously as the atomic number Z *** cross sections of the superheavy nuclei at Z = 112.and 115 are enhanced as compared with the whole Z-trend in synthesis of the superheavy nuclei,which clearly illustrates that the reactions with large negative Q-value and shell correction are more favorable to synthesize superheavy nuclei.

关键词： superheavy nuclei fusion reaction cross section 2.8U target

How random are matrix elements of the nuclear shell model Hamiltonian?

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2009年第10期52卷 1477-1481页

作者： SHEN JiaJie1 & ZHAO YuMing1,2.3.4 1 Department of physics,Shanghai Jiao Tong University,Shanghai 2.02.0,china 2.{2. of Theoretical Nuclear physics,National Laboratory of Heavy Ion Accelerator,Lanzhou 73.000,china 3.Nishina {2.,institute of Physical Chemical Research(RIKEN),Hirosawa 2.1,Wako-shi,Saitama 3.1-0198,Japan 4 CCAST,World Laboratory,beijing {13.,china Department of physics Shanghai Jiao Tong University Shanghai China center of Theoretical Nuclear physics National Laboratory of Heavy Ion Accelerator Lanzhou China Nishina center Institute of Physical Chemical Research (RIKEN) Saitama Japan

In this paper we study the general behavior of matrix elements of the nuclear shell model *** find that nonzero off-diagonal elements exhibit a regular pattern,if one sorts the diagonal matrix elements from smaller to larger *** correlation between eigenvalues and diagonal matrix elements for the shell model Hamiltonian is more remarkable than that for random matrices with the same distribution unless the dimension is small.

关键词： nuclear shell model geometry property linear correlation randomize

High-sensitivity photovoltage based on the interfacial photoelectric effect in the SrTiO_(3.δ)/Si heterojunction

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11期53卷 2080-2083页

作者： WEN Juan 1,GUO HaiZhong 1,XING Jie 2.Lü HuiBin 1,JIN Kui-Juan 1,HE Meng 1 & YANG GuoZhen 1 1 beijing National Laboratory for condensed {2. {3.,institute of {3.,Chinese Academy of Sciences,beijing 100190,china 2.School of Materials Sciences and Technology,china University of Geosciences,beijing 100083.china beijing National Laboratory for condensed {2.{3. Institute of Physics Chinese Academy of Sciences Beijing China School of Materials Sciences and Technology China University of Geosciences Beijing China

A high sensitivity photovoltaic effect has been observed in a heterojunction composed of n-type wide bandgap oxide SrTiO 3.δ and p-type Si fabricated by laser molecular beam *** responsivity of open-circuit photovoltage can reach 10 4 V/W without any amplification under zero bias for the wavelength range from visible to near infrared light in nW-μW *** attribute the high performance of the photovoltage responsivity to the interfacial photoelectric effects in the SrTiO 3.δ /Si *** the experimental results,some ideas can be generalized to improve photovoltaic efficiency and develop high sensitivity photodetectors with wide bandgap oxide materials and Si.

关键词： SrTiO 3.δ/Si heterojunction interfacial photoelectric effect photovoltage