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Multi-player and Multi-choice Quantum Game
DU Jiang-Feng, LI Hui, XU Xiao-Dong, ZHOU Xian-Yi, HAN Rong-Dian,
Chin. Phys. Lett. 2002, 19 (9):
1221-1224
.
We investigate a multi-player and multi-choice quantum game. We start from a two-player and two-choice game, and the result is better than its classical version. Then we extend this to N-player and N-choice cases. In the quantum domain, we provide a strategy with which players can always avoid the worst outcome. Also, by changing the value of the parameter of the initial state, the probabilities for players to obtain the best pay-off will be much higher that in its classical version.
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Band (5, 0) in the Red System A2II1 - X2Σ+ of CN Studied by Optical Heterodyne Magnetic Rotation Enhanced Concentration Modulation Spectroscopy
XU Chao-Xiong, WU Ling, LIU Jin-Jun, WU Sheng-Hai, DUAN Chuan-Xi, CHEN Yang-Qin, LIU Yu-Yu,
Chin. Phys. Lett. 2002, 19 (9):
1277-1279
.
We study the CN radical using optical heterodyne magnetic rotation enhanced concentration modulation spectroscopy in the visible region. The radical has been produced in the ac glow discharge of acetonitrile with helium as the carrier gas. The (5, 0) band of the red system A2II1 - X2Σ+ in the range 17450--17830cm-1 has been observed and rotationally analysed. We determine a set of precise molecular constants for the v = 5 vibrational level of CN in the A2II1 state.
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Assignment of Infrared and Far-Infrared Transitions of
CH2CF2
LIU Yu-Yan, HUANG Guang-Ming, SHI Li-Hua, DUAN Chuan-Xi
Chin. Phys. Lett. 2002, 19 (9):
1280-1282
.
Starting from the Watson A-reduced Hamitonian and considering the infrared transitions with ΔKa = 0, ΔKc = ±1 (A-type) or ΔKa = ±1, ΔKc = ±1 (B-type), and the far-infrared transitions with ΔKa = 0,±2 and ΔKc = ±1, we calculate all the possible infrared absorption and far-infrared emission transitions of the v4 and v9 bands of 1,1-difluoroethylene (CH2CF2) pumped by 10P10 and 10P12 CO2 laser lines, and assign four previously unassigned CH2CF2 far-infrared laser lines (291.3μm, 339.3μm, 349.5μm and 657.9μm), where Ka and Kc represent the quantum number K of the limiting prolate top and the limiting oblate top, respectively. The 291.3μm line is identified to be generated from the cascade transition. The assignment of the 288.5μm line by Lafferty et al. (J. Mol. Spectrosc. 87(1981)416) is also confirmed.
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High Spatial Resolution of an Optical Addressing Spatial Light Modulator Made by Photorefractive Semi-insulting Multiple Quantum Wells
CHEN Jing, LI Chun-Yong, HAN Ying-Jun, GUO Li-Wei, HUANG Qi, ZHANG Zhi-Guo, TANG Jun-Xion, DUAN Ming-Hao
Chin. Phys. Lett. 2002, 19 (9):
1291-1292
.
We use nondegenerate four-wave mixing to study the spatial resolution of photorefractive semi-insulating multiple quantum wells grown by molecular beam epitaxy. By optimizing the experimental conditions, we have demonstrated that our sample has spatial resolution up to 2.5μm, which approaches the theoretical limit. We also analyse the factors that affect the spatial resolution of multiple quantum wells.
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High Efficient Laser Operation of the High-Doped Nd:YAG Crystal Grown by Temperature Gradient Technology
MAO Yan-Li, DENG Pei-Zhen, ZHANG Ying-Hua, GUO Ju-Pin, GAN Fu-Xi
Chin. Phys. Lett. 2002, 19 (9):
1293-1295
.
We investigate the optical properties of Nd:YAG crystals grown by temperature gradient technology with different Nd-doping levels. The Nd concentrations used are 1.0at.%, 1.5at.%, 2.0at.%, 2.5at.%, and 3.0at.%, respectively. It is found that the absorption coefficients of Nd:YAG crystals increase with the increasing Nd concentrations. The absorption coefficient of 3.0at.% Nd:YAG is up to 22.1cm-1. The laser performance of these Nd:YAG crystals is compared with that of the traditional Nd:YAG (1.1at.% Nd) grown by the Czochralski (CZ) method. Although concentration quenching exists in highly doped Nd:YAG, 2.0at.% Nd:YAG shows excellent performance with the slope efficiency of 46.7%, which is higher than that (39%) of 1.1at.% Nd:YAG grown by the CZ method.
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Phase Transition and Temperature Dependence of the A1 Low-Frequency Exciton Band Parameters in Quaternary Compound Rb0.5Cs0.5Ag4I5 Thin Films
SUN Jia-Lin, TIAN Guang-Yan, CAO Yang, SHI Shuo, TAN Xiao-Jing, CHEN Tao
Chin. Phys. Lett. 2002, 19 (9):
1326-1328
.
The absorption spectra of the A1 low-frequency exciton band in quaternary compound Rb0.5Cs0.5Ag4I5 thin films have been measured by an UV-2100 spectrophotometer at the temperature (T) range from 78 to 289 K. The measurements at intermediate temperatures are performed within an interval of photon energies from 3.44 to 3.70 eV. The spectra have been computer-processed to separate the A1 band from the interband absorption edges, and to determine their parameters: the spectral peak position (Em), the half-width (G) of the exciton band, and the Gaussian shape ratio in the spectrum. The results show that at T < 107 K, dEm/dT = -6.34 x 10-4 eV.K-1, dG/dT = 3.04 x 10-4 eV.K-1; at T > 107 K, dEm/dT = -3.01 x 10-4 eV.K-1, dG/dT = 5.47 x 10-4 eV.K-1. It is emphasized that the phase transition γ → β in this material is carried out at temperature 107 K.
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Energy and Charge Transfer from Guest to Host in Doped Organic
Electroluminescent Devices
LI Hong-Jian, PENG Jing-Cui, XU Xue-Mei, QU Shu, LUO Xiao-Hua, ZHAO Chu-Jun
Chin. Phys. Lett. 2002, 19 (9):
1356-1358
.
The luminescence properties of doped organic electroluminescent devices are explained by means of a Hamiltonian model. The results show that there is a corresponding relation between the amount of the transferred charge and the change of the energy originated from charge transfer, and the relation can be influenced by dopant concentration. As the amount of the transferred charge increases, the total energy decreases and the luminescence intensity increases. Therefore, we deduce that the energy transfer from guest to host may be derived from the charge transfer. For a given organic electroluminescent device, the maximum value of the conductivities can be observed in a specific dopant concentration. The calculated results show that the greater the transferred charges, the higher the conductivities in doped organic electroluminescent devices. The results agree basically with experimental results.
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Novel Alternating Current Electroluminescent Devices with an
Asymmetric Structure Based on a Polymer Heterojunction
TAN Hai-Shu, YAO Jian-Quan, WANG Xin, WANG Peng, XIE Hong-Quan
Chin. Phys. Lett. 2002, 19 (9):
1359-1361
.
Novel alternating current electroluminescent devices with an
asymmetric structure are successfully fabricated by using a hole-type polymer, poly (2,5-bis (dodecyloxy)-phenylenevinylene) (PDDOPV) and an electron-type polymer, poly (phenyl quinoxaline) (PPQ). The performance of the polymer devices with heterojunction under ac operation is insensitive to thickness of the two polymer layers, compared to that under dc operation. This new advantage means an easy and cheap production facility on a large scale in the near future. Different emission spectra are obtained when our ac devices are operated in an ac mode, forward, or reverse bias. The emission spectrum at reverse bias includes two parts. One from PDDOPV and the other is from PPQ.
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Doping in the Mixed Layer to Achieve High Brightness and Efficiency Organic Light Emitting Devices
GAO Wen-Bao, YANG Kai-Xia, LIU Hong-Yu, FENG Jing, LIU Shi-Yong
Chin. Phys. Lett. 2002, 19 (9):
1362-1364
.
Doping in the mixed layer was introduced to fabricate high brightness and high efficiency organic light-emitting devices, in which a copper phthalocyanine (CuPc) film acts as the buffer layer, a naphthylphenybiphenyl amine (NPB) film as the hole-transport layer and a tris (8-hydroxyquinolinolate)aluminum (Alq3) film as the electron-transport layer. The luminescent layer consists of the mixture of NPB, Alq3 (to be called the mixed layer), and an emitting dopant 5,6,11,12-petraphenylnaphthacene (rubrene), where the concentration of NPB declined and the concentration of Alq3 was increased gradually in the deposition process. Adopting this doping mixed layer, the device exhibites the maximum emission of 49300cd/m2 at 35V and the maximum efficiency of 7.96cd/A at 10.5V, respectively, which have been improved by twice in comparison with the conventional doped devices. We attribute this improvement to the effective confinement of carriers in the mixed layer, which leads to the increase of the recombination efficiency of carriers.
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Microstructure and Optical Absorption Properties of Cu-MgF2 Nanoparticle Cermet Film
SUN Zhao-Qi, , SUN Da-Ming, RUAN Tu-Nan,
Chin. Phys. Lett. 2002, 19 (9):
1365-1368
.
The microstructure and optical absorption spectra of 10-30vol% Cu-MgF2 nanoparticle cermet films prepared by co-evaporation in vacuum are examined. The results show that the Cu-MgF2 cermet films are mainly composed of amorphous MgF2 matrix with embedded fcc-Cu nanoparticles of average size 12-24 nm. The results also show that the optical absorption of the films decreases as the wavelength increases in the range of 200-800 nm. The surface plasmon resonance absorption peaks of Cu nanoparticles in 10, 20, and 30vol% Cu-MgF2 films appear at 578, 588, and 606nm, respectively, and the interband transition absorption of Cu starts from 590 nm downwards. Based on the Maxwell-Garnett theory, the experimental optical absorption properties of the films have been quantitatively evaluated.
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Twins Diamond Crystals Grown at High Temperature and High
Pressure from the Fe-Ni-C System
YIN Long-Wei, YUAN Quan, LI Mu-Sen, LIU Yu-Xian, XU Bin, HAO Zhao-Yin
Chin. Phys. Lett. 2002, 19 (9):
1371-1373
.
Twin diamond crystals grown at high temperature and high pressure (HPHT) in the presence of FeNi catalyst have been xamined by transmission electron microscopy (TEM). Direct observation by TEM shows that there are a large amount of twins which lie on the {111} planes in the HPHT-grown diamonds. The twins in the diamond may be formed and may extend into the inner crystal from the twin nucleus formed in the nucleation process. The twins can be formed due to the carbon atoms falling mistakingly into positions where a twin crystal can form during diamond growth, or condensation of supersaturated vacancies on the {111} plane. Some hexagonal dislocation loops related to supersaturated vacancies are found on the twins. The Moiré fringe image reveals that stacking faults terminate on intersecting twin boundary. This suggests that, at the temperature that the HPHT diamond is grown, the bordering partial has propagated by gliding up to the twin interface, which can be described by the reaction of a Shockley partial dislocation with a twin on the {111} plane.
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High-Tc Superconductor Detection Coils for a Magnetic Resonance System
KANG Lin, WU Pei-Heng, PAN Jun, CAI Wei-Xing, YANG Sen-Zu, CAO Chun-Hai
Chin. Phys. Lett. 2002, 19 (9):
1380-1381
.
Considering that in a magnetic resonance system, if the detection coil contributes dominantly to the system noise, the performance of the whole system can certainly be improved by switching to a detection coil made of high-temperature superconductor, and using YBa2Cu3O7 thin films on 25 x 25mm2 LaAlO3 substrates, we have prepared two kinds of detection coils, i.e., single-coil and two-coil. Encouragingly, their quality factors are measured to be Q > 2500 for two-coil (at 22.566 MHz and 77 K) and Q > 5500 for single-coil (at 92.3 MHz and 77 K), respectively. Here, we describe the details of the design, fabrication and tests of the coils.
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Observation of the in-vivo Reporter of Green Fluorescent Protein in a Plant Root by Scanning Near-Field Optical Microscopy
SUN Jia-Lin, XU Jian-Hua, CHEN Tao, TAN Xiao-Jing, CAO Yang, LIU Jin-Yuan, XIE Ai-Fang, ZHANG Ze-Bo, GUO Ji-Hua
Chin. Phys. Lett. 2002, 19 (9):
1389-1391
.
An in vivo reporter of green-fluorescent protein (GFP) in a living plant root has been imaged by scanning near-field optical microscope (SNOM) in the transmission mode. The exciting light is 488 nm wavelength of the argon ion laser and the bandpass filters (514±10) nm is put into the detecting optical pathway. The results indicate that in the living plant cells, the GFPs gather together and form an area of 2-4μm, rather than being individually distributed. The transmission coefficient of the eigenfunction is incorporated into Bethe's theoretical model modified by Grober, and the near-field excited light intensity along the fibre probe axis (z-axis) in the air medium and biological medium is calculated. Based on that, along the z-axis direction of the GFP detected in the sample, numerous GFPs locate near the epidermal cells wall (in the range of 0-38 nm) in the living root. The experiments show that SNOM has an advantage of optical nanometer-scale resolution along the z-axis.
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56 articles
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