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Peakon and Foldon Excitations In a (2+1)-Dimensional Breaking Soliton System
ZHENG Chun-Long, , ZHANG Jie-Fang, HUANG Wen-Hua, CHEN Li-Qun
Chin. Phys. Lett. 2003, 20 (6):
783-786
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Starting from the standard truncated Painlevé expansion and a variable separation approach, a general variable separation solution of the breaking soliton system is derived. In addition to the usual localized coherent soliton excitations like dromions, lumps, rings, breathers, instantons, oscillating soliton excitations, and previously revealed chaotic and fractal localized solutions, some new types of excitations, peakons and foldons, are obtained by introducing appropriate lower dimensional piecewise smooth functions and multiple valued functions.
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Thermal Charmed Quark Contribution to Dileptons in Chemically Equilibrating Quark-Gluon Matter
HE Ze-Jun, , LONG Jia-Li, LU Zhao-Hui, MA Yu-Gang, LIU Bo
Chin. Phys. Lett. 2003, 20 (6):
836-838
.
We find that in a chemically equilibrating baryon-rich quark-gluon matter, due to the slow cooling rate, high initial temperature, large gluon density as well as large fusion cross section of gg → cc in the intermediate mass region, the gluon fusion gg → cc provides a dominant contribution to dileptons with intermediate masses, resulting in the significant enhancement of intermediate mass dileptons.
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Experimental Scaling for Mass Ablation Rate in Planar Targets Irradiated by Smoothed 0.351μm Laser Beam
YANG Jia-Min, DING Yao-Nan, ZHANG Bao-Han, YANG Guo-Hong, ZHENG Zhi-Jian, ZHANG Wen-Hai, HU Xin, WANG Yao-Mei, ZHANG Ji-Yan, LI Jun
Chin. Phys. Lett. 2003, 20 (6):
877-880
.
Layered planar targets, consists of Al and Au layers, were irradiated by smoothed 0.351-μm-high power laser with relatively large focus spot on Xingguang II laser facility. The burnthrough time of laser ablation to Al sample has been obtained by measuring the delay time of Au N-Band x-ray emission with respect to the Al K-Band x-ray emission. The scaling law of mass ablation rate with the laser flux has been obtained by only varying the laser energy on the target surface on different shots. The experimental scaling law is greatly different from the results of Key et al. [Phys. Fluids 23(1983) 2011] and is in good agreement with the analytical model.
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Mesoscopic Transport Characteristics of a Normal-Metal-Superconducting-Grain- Superconductor System
FENG Jin-Fu, XIONG Shi-Jie
Chin. Phys. Lett. 2003, 20 (6):
897-900
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We investigate transport properties of a normal-metal-superconducting-grain-superconductor system by the use of the equivalent single-particle multi-channel networks, taking into account the multi-level structure, the Coulomb interaction, and the pair potential on the grain. The dependence of the current on the gate voltage shows oscillating behaviour with a period related to 2e of the charge on the grain, reflecting the charge transfer in units of Cooper pairs. The conductance can be enhanced when the pairing parameter is near the Coulomb energy e2/2C, due to the resonance of the Andreev reflection through the grain. The magnitude of the Andreev reflection as a function of the bias voltage exhibits complicated structures, reflecting the multiple levels, the spin orientations, and the interaction energy on the grain.
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Spectral Properties of Erbium-Doped Oxyfluoride Silicate Glasses for Broadband Optical Amplifiers
XU Shi-Qing, YANG Zhong-Min, DAI Shi-Xun, YANG Jian-Hu, WEN Lei, HU Li-Li, JIANG Zhong-Hong
Chin. Phys. Lett. 2003, 20 (6):
905-908
.
The new oxyfluoride silicate glasses of Er3+-doped 50SiO2-(50-x)PbO-xPbF2 were prepared. With increasing PbF2 content in the glass composition, the fluorescence full width at half max maximum and lifetimes of the 4I13/2 level of Er3+ increase, while the refractive indices and densities decrease. Er3+-doped 50SiO2-50PbF2 glass showed broad fluorescence spectra of 1.55μm with a large stimulated emission cross-section and long lifetimes of 4I13/2 level of Er3+. Compared with other glass hosts, the gain bandwidth properties of Er3+-doped 50SiO2-50PbF2 glass are close to those of tellurite and bismuth glasses, and have advantages over those of silicate, phosphate and germante glasses. The broad and flat 4I13/2 → 4I15/2 emission of Er3+ around 1.55μm can be used as host material for potential broadband optical amplifier in wavelength-division-multiplexing network system.
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Magnetic Properties and Magnetoresistance of HfFe6Ge6-Type Er1-xGdxMn6Ge6 and Ho1-xGdxMn6Ge6 (0.2 ≤ x ≤ 0.9) Compounds
ZHANG Li-Gang, WANG Ru-Wu, LI-Lu, ZHANG Shao-Ying, YAO Jin-Lei, SHEN Bao-Gen
Chin. Phys. Lett. 2003, 20 (6):
915-918
.
Magnetic properties and magnetoresistance effects of the Er1-xGdxMn6Ge6 and Ho1-xGdxMn6Ge6 (0.2 ≤ x ≤ 0.9) compounds have been studied by magnetic property and resistivity measurements in applied magnetic field up to 5 T. For increasing Gd content, two series display a transition from the antiferromagnetic state to the ferrimagnetic state. The Er1-xGdxMn6Ge6(x = 0.2 and 0.5) and Ho1-xGdxMn6Ge6 (x = 0.2 and 0.4) compounds order antiferromagnetically at 430, 432, 423 and 425 K, respectively. The Er1-xGdxMn6Ge6 (x = 0.8 and 0.9) and Ho1-xGdxMn6Ge6 (x = 0.7, 0.8 and 0.9) compounds order ferrimagnetically at 462, 471, 450, 463 and 470 K, respectively. The Er1-xGdxMn6Ge6 and Ho1-xGdxMn6Ge6 compounds undergo the second transitions below 71 and 82 K, respectively. The magnetoresistance curves of the Er0.1Gd0.9Mn6Ge6 and Ho0.1Gd0.9Mn6Ge6 compounds in a field of 5 T are presented and the magnetoresistance effects are related to the metamagnetic transitions.
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Synthesis and Strong Blue-Green Emission Properties of ZnO Nanowires
LIU Dong-Fang, TANG Dong-Sheng, CI Li-Jie, YAN Xiao-Qin, LIANG Ying-Xin, ZHOU Zhen-Ping, YUAN Hua-Jun, ZHOU Wei-Ya, WANG Gang
Chin. Phys. Lett. 2003, 20 (6):
928-931
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ZnO nanowires were catalytically grown on Au-coated silicon substrates by the carbon thermal reduction method. The process involved addition of a low partial pressure of hydrogen sulfide to the argon carrier flow. The addition of H2S led to the higher yield and longer nanowires without any morphology change, and no sulfuric content was observed by the energy dispersive x-ray spectroscopy in the resulting nanowires. The nanowires exhibited strong blue-green emission at room temperature and an increasing intensity when the partial pressure of H2S was raised. The temperature-dependent photoluminescence spectra show that intensity of the blue-green emission, almost without shift, decreases slowly with increasing temperature. Heat treatments indicated that quenching resulted in a higher ratio of blue-green emission to ultraviolet emission.
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Field Emission from Amorphous Carbon Nitride Films Deposited on Silicon Tip Arrays
LI Jun-Jie, ZHENG Wei-Tao, SUN Long, BIAN Hai-Jiao, JIN Zeng-Sun, ZHAO Hai-Feng, SONG-Hang, MENG Song-He, HE Xiao-Dong, HAN Jie-Cai
Chin. Phys. Lett. 2003, 20 (6):
944-946
.
Amorphous carbon nitride films (a-CNx) were deposited on silicon tip arrays by rf magnetron sputtering in pure nitrogen atmosphere. The field emission property of carbon nitride films on Si tips was compared with that of carbon nitride on silicon wafer. The results show that field emission property of carbon nitride films deposited on silicon tips can be improved significantly in contrast with that on wafer. It can be explained that field emission is sensitive to the local curvature and geometry, thus silicon tips can effectively promote field emission property of a-CNx films. In addition, the films deposited on silicon tips have a smaller effective work function (F = 0.024 eV) of electron field emission than that on silicon wafer (F = 0.060 eV), which indicates a significant enhancement of the ability of electron field emission from a-CNx films.
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High-Efficiency Organic Double-Quantum-Well Light-Emitting Devices Using 5,6,11,12-Tetraphenylnaphthacene Sub-monolayer as Potential Well
XIE Wen-Fa, LI Chuan-Nan, LIU Shi-Yong
Chin. Phys. Lett. 2003, 20 (6):
956-958
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The double-quantum-well organic light-emitting devices of indium-tin-oxide (ITO)/NPB (50 nm)/rubrene (0.05 nm)/ NPB(4 nm)/rubrene (0.05 nm)/Alq3 (50 nm)/LiF (0.5 nm)/Al were fabricated, in which N,N-bis-(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine (NPB) is used as a barrier potential or hole transport layer, tris (8-hydroxyquinoline) aluminum (Alq3) used as electron transport layer, and 5,6,11,12-tetra\-pheny\-lnaphthacene(rubrene) as a potential well and emitter. The brightness can reach 18610 cd/m2 at 13 V. The maximum electroluminescent efficiency of the device was 6.61 cd/A at 7 V, which was higher than that of common dope-type devices. In addition, the electroluminscence efficiency is relatively independent of the drive voltage in the range from 5 to 13 V.
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57 articles
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