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Dynamical Equation of Post Newtonian Quasi-rigid Body
XU Chong-Ming, TAO Jin-He, HUANG Tian-Yi, WU Xue-Jun
Chin. Phys. Lett. 2004, 21 (10):
1884-1886
.
We derive the dynamical equation of a post Newtonian (PN) quasi-rigid body from the general rotational equation of motion, i.e. the PN rotational equation of motion for a quasi-rigid body. It is emphasized that a rotational angular velocity vector and a figure axis besides the first post Newtonian (1PN) spin vector can be defined and realized for the model of a PN quasi-rigid body model constructed recently. Actually, we have shown that the moment of inertia tensor of a quasi-rigid body can be transformed into a diagonal form by an orthogonal transformation, which defines the principal axes of inertia of the body. As an example, its torque-free motion is discussed and a PN Poinsot configuration, which is similar to the Newtonian one with a small 1PN correction, is solved.
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Strangeness Production in Ultrarelativistic Nucleus-Nucleus Collisions
LONG Jia-Li, HE Ze-Jun, , MA Yu-Gang, , MA Guo-Liang,
Chin. Phys. Lett. 2004, 21 (10):
1900-1903
.
Based on the relaxation equations describing the chemical quilibration of gluons, quarks and s quarks at finite baryon ensity derived from the Jüttner distribution of partons, with the help of a rapid phase transition scenario from quark hase to hadron phase, we calculate strangeness production in the quark phase and hadron phase. It is found that the K-/π- ratio is enhanced to be larger than that in pp collisions by about a factor 3.
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High-Spin Structure in Neutron-Rich 108Ru Nucleus
CHE Xing-Lai, ZHU Sheng-Jiang, J. H. Hamilton, A. V. Ramayya, J. K. Hwang, U Yong-Nam, LI Ming-Liang, ZHENG
Rang-Chen, I. Y. Lee, J. O. Rasmussen, Y. X. Luo, W.C.Ma
Chin. Phys. Lett. 2004, 21 (10):
1904-1907
.
High spin states in the neutron-rich 108Ru nucleus have been studied through measuring prompt γ-ray coincidences following the spontaneous fission of 252Cf with the Gammasphere detector array. The yrast band has been confirmed. The one-phonon γ-vibrational band and the two-quasiparticle band based on the 5- level have been extended up to 13+ and 15-, respectively. In addition, two levels at 1644.8keV and 1826.5keV excitation energies are newly identified and proposed to be the members of a two phonon γ-vibrational band. It is shown that the 108Ru nucleus has triaxial deformation with parameters β2~0.29 and γ=-22°from the total Routhian surface calculations. The observed band crossing in the yrast band is due to the alignment of a pair of h11/2 neutrons according to the cranked shell model calculations. The possible configuration for the two-quasiparticle band has been discussed.
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Highly Sensitive Tunable Diode Laser Absorption Spectroscopy of CO2 Around 1.31μm
SHAO Jie, GAO Xiao-Ming, DENG Lun-Hua, HUANG Wei, YANG Yong, PEI Shi-Xin, YUAN Yi-Qian, ZHANG Wei-Jun
Chin. Phys. Lett. 2004, 21 (10):
1908-1910
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Fifteen new absorption lines are observed when studying CO2 absorption spectroscopy by wavelength modulation (WM) technique with a distributed feedback laser. The overtone spectra of CO2 around 1.31μm and the corresponding spectral parameters (i.e. positions, intensities, self-broadening coefficients) are presented. The intensity of the weakest line detected is 2.25163×10-27cm-1/(molecule.cm-2 at the pressure of 5Torr, with a corresponding absorption of 3.88×10-8
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Angular Distribution and Angular Dispersion in Collision of 19F+27Al at 114MeV
WANG Qi, DONG Yu-Chuan, LI Song-Lin, DUAN Li-Min, XU Hu-Shan, XU Hua-Gen, CHEN Ruo-Fu, WU He-Yu, HAN Jian-Long, LI Zhi-Chang, LU Xiu-Qin, ZHAO Kui, LIU Jian-Cheng, SERGEY Yu-Kun,
Chin. Phys. Lett. 2004, 21 (10):
1911-1913
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Angular distributions of fragments B, C, N, O, F, Ne, Na, Mg and Al induced by the collision of 19F+27Al at 114MeV have been measured. Angular dispersion parameters are extracted from the experimental data and compared with the theoretical ones. The dynamic dispersions for dissipative products depend strongly on the charge number Z of the fragments.
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Isospin Effect of Coulomb Interaction on Momentum Dissipation in Intermediate Energy Heavy Ion Collisions
LIU Jian-Ye, , GUO Wen-Jun, XING Yong-Zhong, LI Xi-Guo,
Chin. Phys. Lett. 2004, 21 (10):
1914-1917
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We investigate the isospin effect of Coulomb interaction on the momentum dissipation or nuclear stopping in the intermediate energy heavy ion collisions by using the isospin-dependent quantum molecular dynamics model. The calculated results show that the Coulomb interaction induces obviously the reductions of the momentum dissipation. We also find that the variation amplitude of momentum dissipation induced by the Coulomb interaction depends sensitively on the form and strength of symmetry potential. However, the isospin effect of Coulomb interaction on the momentum dissipation is less than that induced by the in-medium nucleon--nucleon cross section. In this case, Coulomb interaction does not change obviously the isospin effect of momentum dissipation induced by the in-medium two-body collision. In particular, the Coulomb interaction is preferable for standing up the isospin effect of in-medium nucleon--nucleon cross section on the momentum dissipation and reducing the isospin effect of symmetry potential on it, which is important for obtaining the feature about the sensitive dependence of momentum dissipation on the in-medium nucleon--nucleon cross section and weakly on the symmetry potential.
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Accuracy Measurements of the CAS-LIBB Single-Particle Microbeam for Single Cell Irradiation
WANG Xu-Fei, HU Zhi-Wen, WANG Xiao-Hua, CHEN Lian-Yun, ZHANG Jun, LI Jun, CHEN Bin, XU Ming-Liang, WU Yu, WU Li-Jun, YU Zeng-Liang
Chin. Phys. Lett. 2004, 21 (10):
1922-1925
.
A single-particle microbeam facility has been constructed at the Laboratory of Ion Beam Bioengineering (LIBB), Chinese Academy of Sciences. The system is designed to deliver the defined number of hydrogen ions, covering a range of energy from 1.0 to 3.5MeV, into an area smaller than the nuclei of individual living cells. Accuracy of the particle detection system and the cell targeting system in the facility has been assessed using CR39 (nuclear track detector) for 2.3MeV protons. The results demonstrate that the particle detection efficiency is above 98%, and the overall targeting accuracy of the microbeam is limited within 3μm for more than 90% hits.
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High-Power Red Light Generation by Intra-Cavity Frequency-Doubling of a Side-Pumped Nd:YAG Laser in a LiB3O5 Crystal
SUN Zhi-Pei, LI Rui-Ning, BI Yong, YANG Xiao-Dong, BO Yong, HOU Wei, ZHANG Ying, WANG Gui-Ling, ZHAO Wu-Li, ZHANG Hong-Bo, CUI Da-Fu, XU Zu-Yan
Chin. Phys. Lett. 2004, 21 (10):
1951-1953
.
We report the generation of high-power red light radiation of 11.2W in a LiB3O5(LBO) crystal with intra-cavity frequency doubling of two compact and simple side-pumped Nd:YAG laser modules under a repetition rate of 3.5kHz. The pulse width of output is about 180±20,ns. The beam quality of the M2 value is 15±3 in both the directions. This excellent laser performance demonstrates that the Nd:YAG laser with LBO intracavity frequency doubling is an promising method for generating red light with high brightness.
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High Two-Beam Coupling Coefficients of Monolithic Small Molecule at Low Electric Field
ZHANG Jie, CHEN Zhi-Jian, HUANG Mao-Mao, LI Fu-Shan, WEI Qun, LIU Yi-Hong, GONG Qi-Huang
Chin. Phys. Lett. 2004, 21 (10):
1958-1960
.
A novel full-functional photorefractive small molecular material,(9-ethyl-9H-carbazol-3-ylmethylene)-(4-nitro-phenyl)-amine (ECYENPA), was synthesized and its photorefractivity was studied by two-beam coupling experiments at a wavelength of 632.8nm. The glass transition temperature of ECYENPA, as low as -5°C, results in the chromophore being orientated easily at room temperature. High two-beam coupling coefficient was obtained to be 232cm-1 at an electric field of 44.6V/μm.
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A Random Number Generator Based on Quantum Entangled Photon Pairs
MA Hai-Qiang, WANG Su-Mei, ZHANG Da, CHANG Jun-Tao, JI Ling-Ling, HOU Yan-Xue, WU Ling-An
Chin. Phys. Lett. 2004, 21 (10):
1961-1964
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A new scheme for a random number generator based on quantum entangled photon pairs is demonstrated. Signal photons produced by optical parametric down-conversion are detected at two single-photon detectors after transmission or reflection at a 50/50% beamsplitter, to form a truly random binary sequence. Their arrival is signalled by their twin idler photons, so that a cw laser source may be used instead of attenuated laser pulses. Coincidence measurement is employed to obtain the bit sequences, which are shown to fully satisfy the standard tests for randomness.
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All-Optical Photorefractive Effect in Bihole-Transporting System Polymeric Composites
HUANG Mao-Mao, CHEN Zhi-Jian, ZHANG Jie, WEI Qun, LIU Yi-Hong, GONG Qi-Huang, BAI Yao-Wen, CHEN Xiao-Fang, WAN Xin-Hua, ZHOU Qi-Feng
Chin. Phys. Lett. 2004, 21 (10):
1969-1972
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Photorefractive (PR) composites based on poly(N-vinylcarbozale) and azobenzene have been fabricated. Two-beam-coupling and four-wave-mixing phenomena were observed in the absence of an external electric field or prepoling. The maximum two-beam-coupling gain coefficient and the refractive index modulation were measured to be 79cm-1 and 2.2×10-4 respectively. The all-optical-PR phenomenon is explained based on the photoassisted poling of the azo dye by the synergism of the photoisomerization and the longitudinal electric field due to longitudinal intensity gradient of writing light beams. The bi-hole-transporting system provides more charge-carrier traps resulting in improvement of PR performance.
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Structures and Properties of Zr--N Films Prepared by ECR-Microwave Plasma Source Enhanced Direct-Current Magnetron Sputtering Under Different N2 Partial Pressures
LIU Tian-Wei, DENG Xin-Lu, WAN Xiao-Ying, WANG Ying-Min, ZOU Jian-Xin, DONG Chuang
Chin. Phys. Lett. 2004, 21 (10):
2008-2011
.
ZrN thin films were prepared on 45# steel by using ECR-microwave plasma source enhanced dc magnetron sputtering. The increase of the N2 partial pressure PN2 leads to phase transitions from ZrN and an orthorhombic ZrNx phase to an amorphous phase. At PN2=1.1×10-2Pa to 4.5×10-2Pa, the films contain both ZrN and ZrNx (a=0.3585, b=0.4443, c=0.5798nm). At PN2=5.0×10-2Pa, the film shows a strong tendency towards the amorphous phase. The N concentration at different PN2 varies from 7.73 to 66.96% according to electron probe analysis. The microhardness of the samples, varying from 19.82GPa to 26.73GPa, first increases and then decreases with increasing PN2. The hardest sample has a wear rate of about 4.5×10-5mg/min. The property changes are relative to the film structure due to different N2 partial pressures.
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Field Dependence of Magnetization and dM/dH for Sm- and Gd-Doped Bi1.7Pb0.3Sr2Ca2-xRExCu3O10+y Compounds
Atilla COSKUN, Ahmet EKICIBIL, Bekir ö, ZCELIK, Kerim KIYMAC
Chin. Phys. Lett. 2004, 21 (10):
2041-2044
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We have performed magnetization measurements as a function of magnetic fields up to 4kOe on Bi1.7Pb0.3Sr2Ca2-xRExCu3O10+y (RE: Gd0.01, Sm0.03, at different fixed temperatures T< Tc in the range 15≤T≤75K. We have observed three important features. Firstly, the dM-dH curves of both the Sm- and Gd-doped samples are similar and each shows a minimum of M at a certain critical field Hc, above which there appears to be a monotonic decrease in magnitude. Secondly, the magnitude of the initial susceptibility dM/dH, related to the superconducting volume, decreases with increasing temperature. In other words, the decrease of dM/dH with T indicates that the superconducting regions reduce in size and the paramagnetic domains probably grow at the expense of superconductivity. The third feature is the fast decrease of hysteresis loops in both the Gd and Sm doped samples with increasing temperature, which implies existence of flux pinning centres. Thus the results show that the Ca2+→ Sm3+ and Gd3+ substitution decreases the hole carrier concentration and hence the volume fraction of the superconducting phase.
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Full Aging in Spin Glass State of Y0.90Na0.10MnO3
CHEN Wei-Ran, ZHANG Fu-Chang, MIAO Jun, XU Bo, DONG Xiao-Li, CAO Li-Xin, QIU Xiang-Gang, ZHAO Bai-Ru
Chin. Phys. Lett. 2004, 21 (10):
2045-2048
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We study the decays of the thermoremanent magnetization in Y0.90Na0.10MnO3 for different waiting times at the measuring temperature 33K, well below the spin glass (SG) transition temperature 42K. The results demonstrate that almost perfect full aging can appear even in the case of the cooling time as long as 700s from 60K to 33K. By subtracting the stationary component A(τ0t)a (A is a dimensionless constant, t represents the time, τ0 is the microscopic spin flipping time, and α is a parameter always in the rang of 0.1-0.01), the value of α is found to be much smaller than that reported in other SG systems, which is well consistent with the behaviour of the ac susceptibility. All of them are discussed based on the intrinsic geometric magnetic frustration for the present system.
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Identification of Three Weak Lines and Their Influences on Diagnostics of Electron Temperature and Density in Astrophysical Plasmas
LIANG Gui-Yun, ZHAO Gang, SHI Jian-Rong, ZENG Jiao-Long, BIAN Xia
Chin. Phys. Lett. 2004, 21 (10):
2063-2066
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By comparing of the spectra from the Chandra LETGs observation with the synthetic spectra of argon, we identify two weak emission lines, that is, the Ar XV 27.470Å line with transition 2s3p 1P1-2s2 1S0 and the Ar XVI 27.872Å line with transition 3d 2D3/2-2p2P1/2, which blend with the N VII Lyα emission line. Several second-order spectral lines are also identified, one of which is the second-order Fe XVIII 14.534Å line with transition 2p4(3P)3d2F5/2-2p5 2P3/2, which blends with the inter-combination line of He-like N VI. In order to study the effects of these new identified weak lines on the electron temperature and density, we diagnose the two parameters using the intensity ratio of triplets of the He-like N VI and that of resonance lines of H- and He-like N. In the literature, there is a discrepancy of the temperatures deduced from N VI from other He-like ions, such as C V and O VII. The discrepancy disappears after the contribution of these weak lines is taken into account.
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58 articles
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