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Kinematics of the high-excitation HH 890 jet in the Rosette Nebula

Chinese Journal of Astronomy and Astrophysics 2009年第5期9卷 577-584页

作者： jin-zeng Li National Astronomical Observatory Chinese Academy of Sciences Beijing 100012 China

Photoionized jets immersed in HII regions display special properties, which made them a distinctive category of Herbig-Haro （HH） flows. Detailed studies of such jet systems became one of the key issues in our understanding of jet production and evolution. HH 890, initially called the Rosette HH2 jet, is the second photoionized jet discovered in the spectacular HII region of the Rosette Nebula. Contrary to conventional impressions of a jet, its discrete components are found to be unexpectedly broad and spatially detached from the proposed energy source. The jet displays additional unusual features which point to the disputable nature of the system. Here, we investigate the kinematics of the jet through high-quality echelle spectrograms. It is distinctively resolved into a fast component with a mean approaching velocity of-39 km s^-1 with respect to the systemic rest frame and a slow component with radial velocity centered at -9 km s^-1. The slow component indicates an apparently larger dispersion in radial velocity in various emission lines and is likely dissolving at roughly the speed of sound, which favors a photoevaporated origin. The [SII] doublet ratios indicate an electron density of -1.1×10^3 cm^-3 in the collimated jet and ,-9×10^2 cm^-3 in the HII region. This, along with the diffuse appearance of the extensive part of the jet, leads to a dissipation of the jet in the fully ionized medium of Rosette. In addition, time series of photometric observations provide evidence for remarkable light variations of the energy source. Its amplitudes of variation amount to 〉 1 mag in both R and I, which is commensurate with the young evolutionary status of the source as indicated by a red, late type optical spectrum.

关键词： accretion disks -- ISM jets and outflows -- stars formation -- stars premain-sequence

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Evolutionary Programming for IP/MIP Problems with Linear Constraints

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Journal of Systems Engineering and Electronics 2000年第3期11卷 59-64页

作者： Ren, Qingsheng zeng, jin Qi, Feihu Shanghai Jiaotong Univ Shanghai China

In this paper, we propose a modified evolutionary programming with dynamic domain for solving nonlinear IP/MIP problems with linear constraints, without involving penalty function or any transformation for the problem to a linear model or others. The numerical results show that the new algorithm gives a satisfactory performance in which it works of high speed, and accuracy in IP/MIP problems.

关键词： Algorithms Constraint theory Mathematical models Mathematical transformations Problem solving

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Sequential clustering of star formations in IC 1396

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Research in Astronomy and Astrophysics 2013年第5期13卷 557-570页

作者： Ya-Fang Huang jin-zeng Li National Astronomical Observatories Chinese Academy of Sciences

We present a comprehensive study of the H II region IC 1396 and its star forming activity, in which multi-wavelength data ranging from the optical to the near- and far-infrared were employed. The surface density distribution of all the 2MASS sources with a certain detection toward IC 1396 indicates the existence of a compact cluster spatially consistent with the position of the exciting source of the H II region, HD 206267. The spatial distribution of the sources with excessive infrared emission, selected based on archived 2MASS data, reveals the existence of four sub-clusters in this region. One is associated with the open cluster Trumpler 37. The other three are found to be spatially coincident with the bright rims of the H II region. All the sources with excessive emission in the near infrared are cross-identified with AKARI IRC data. An analysis of the spectral energy distributions （SEDs） of the resultant sample leads to the identification of eight CLASS I, 15 CLASS II and 15 CLASS IH sources in IC 1396. Optical identification of the sample sources with R magnitudes brighter than 17 mag corroborates the results from the SED analysis. Based on the spatial distribution of the infrared young stellar objects at different evolutionary stages, the surrounding sub-clusters located in the bright rims are believed to be younger than the central one. This is consistent with a scenario of sequential star formation in this region. Imaging data of a dark patch in IC 1396 by Herschel SPIRE, on the other hand, indicate the presence of two far-infrared cores in LDN 1111, which are likely to be a new generation of protostellar objects in formation. So we infer that the star formation process in this H II region was not continuous but rather episodic.

关键词： techniques: photometric -- stars: formation -- stars: pre-main sequence-- infrared: stars

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Construction of Paired States in Axially Symmetric Nuclei and Diabolic Pair Transfer

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Chinese Physics Letters 1998年第5期15卷 323-325页

作者： LEI Yi-an zeng jin-yan Department of Physics Peking UniversityBeijing 100871

In axially symmetric nuclei,three forms of paired states can be constructed,i.e.,monopole pair,signature pair and±Ωpair,which are the eigenstates of(J^(2),Jz),(J^(2)_(z),R_(x)(π)),and Jz,*** the cranked shell model,though the energy spectra atω=0 are the same for three types of pair interactions,the spectra and spin alignments forω≠0 are different to a certain *** is found that theωvariation of the pair transfer amplitude,particularly the diabolic pair transfer,is quite different for different pair interactions.

关键词： spectra signature states

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Possibility of Quantum Teleportation and the Reduced Density Matrix

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Chinese Physics Letters 2001年第7期18卷 860-863页

作者： ZHU Hong-Bo zeng jin-Yan Department of Physics Peking UniversityBeijing 100871

It is shown that only the maximally entangled two-particle(spin 1/2)states whose one-particle reduced density matrix isρ(i)=(1/2)I2 can realize the teleportation of an arbitrary one-particle spin *** on this,to teleport an arbitrary k-particle spin state,one must prepare an N-particle entangled state whose k-particle(kk≥2)state,except for special states with only two components.

关键词： state matrix arbitrary

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Modification of Bertrand’s Theorem and Extended Runge-Lenz Vector

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Chinese Physics Letters 1999年第11期16卷 781-783页

作者： WU Zuo-bing zeng jin-yan Department of Physics Peking UniversityBeijing 100871 Laboratory for Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100080

It is shown that for a particle with suitable angular momenta in the screened Coulomb potential or isotropic harmonic potential, there still exist closed orbits rather than ellipse, characterized by the conserved aphelion and perihelion vectors, i.e. extended Runge-Lenz vector, which implies a higher dynamical symmetry than the geometrical symmetry O_(3). The closeness of a planar orbit implies the radial and angular motional frequencies are commensurable.

关键词： Runge implies symmetry

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Dynamic modeling and coupling characteristics of rotating inclined beams with twisted-shape sections

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Frontiers of Mechanical Engineering 2020年第3期15卷 374-389页

作者： jin zeng Chenguang ZHAO Hui MA Bangchun WEN School of Mechanical Engineering and Automation Northeastern UniversityShenyang 110819China Key Laboratory of Vibration and Control of Aero-Propulsion System Ministry of Education Northeastern UniversityShenyang 110819China

In the existing literature, most studies investigated the free vibrations of a rotating pre-twisted cantilever beam;however, few considered the effect of the elastic-support boundary and the quantification of modal coupling degree among different vibration directions. In addition, Coriolis, spin softening, and centrifugal stiffening effects are not fully included in the derived equations of motion of a rotating beam in most literature, especially the centrifugal stiffening effect in torsional direction. Considering these deficiencies, this study established a coupled flapwise–chordwise–axial–torsional dynamic model of a rotating double-tapered, pre-twisted, and inclined Timoshenko beam with elastic supports based on the semi-analytic method. Then, the proposed model was verified with experiments and ANSYS models using Beam188 and Shell181 elements. Finally, the effects of setting and pre-twisted angles on the degree of coupling among flapwise, chordwise, and torsional directions were quantified via modal strain energy ratios. Results showed that 1) the appearance of torsional vibration originates from the combined effect of flapwise–torsional and chordwise–torsional couplings dependent on the Coriolis effect, and that 2) the flapwise–chordwise coupling caused by the pure pre-twisted angle is stronger than that caused by the pure setting angle.

关键词： elastic-support boundary pre-twisted beam semi-analytic method modal strain energy ratio torsional vibration

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A dynamic modeling approach for nonlinear vibration analysis of the L-type pipeline system with clamps

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Chinese Journal of Aeronautics 2020年第12期33卷 3253-3265页

作者： Qingdong CHAI jin zeng Hui MA Kun LI Qingkai HAN School of Mechanical Engineering and Automation Northeastern UniversityShenyang 110819China Key Laboratory of Vibration and Control of Aero-Propulsion Systems Ministry of Education of China Northeastern UniversityShenyang 110819China

There exists a lot of research on the nonlinear vibration of the pipeline system with different boundary *** the best of our knowledge,little research on the actual constraint of the clamp has been *** this paper,according to hysteresis loops of the clamp obtained from experimental test,the simplified bilinear stiffness and damping model is *** the Finite Element(FE)model of L-type pipeline system with clamps is established using Timoshenko beam theory in combination with aforementioned stiffness-damping *** hammering and shaker tests verify the FE model via the comparisons of natural frequencies and vibration *** results show that the maximum errors of natural frequencies and vibration responses are about 8.31%and 17.6%,*** proposed model can simulate the dynamic characteristics of the L-type pipeline system with clamps well,which is helpful to provide some guidance for the early design stage of pipeline in aero-engine.

关键词： Clamp Dynamic modeling Experimental test Finite element Nonlinear vibration Pipeline

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Stress redistribution in multi-stage hydraulic fracturing of horizontal wells in shales

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Petroleum Science 2015年第4期12卷 628-635页

作者： Yi-jin zeng Xu Zhang Bao-Ping Zhang Sinopec Research Institute of Petroleum Engineering

Multi-stage hydraulic fracturing of horizontal wells is the main stimulation method in recovering gas from tight shale gas reservoirs, and stage spacing deter- mination is one of the key issues in fracturing design. The initiation and propagation of hydraulic fractures will cause stress redistribution and may activate natural fractures in the reservoir. Due to the limitation of the analytical method in calculation of induced stresses, we propose a numerical method, which incorporates the interaction of hydraulic fractures and the wellbore, and analyzes the stress distri- bution in the reservoir under different stage spacing. Simulation results indicate the following：（1） The induced stress was overestimated from the analytical method because it did not take into account the interaction between hydraulic fractures and the horizontal wellbore. （2） The hydraulic fracture had a considerable effect on the redis- tribution of stresses in the direction of the horizontal wellbore in the reservoir. The stress in the direction per- pendicular to the horizontal wellbore after hydraulic frac- turing had a minor change compared with the original in situ stress. （3） Stress interferences among fractures were greatly connected with the stage spacing and the distance from the wellbore. When the fracture length was 200 m, and the stage spacing was 50 m, the stress redistribution due to stage fracturing may divert the original stress pat- tern, which might activate natural fractures so as to generate a complex fracture network.

关键词： Shale gas - Horizontal well Multi-stagefracturing Complex fracture Stage spacing - Inducedstress

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Nonlinear Dynamics in a New Double Chain-Model of DNA

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Communications in Theoretical Physics 2001年第12期36卷 737-742页

作者： KONG De-Xing LOU Sen-Yue zeng jin Department of Applied Mathematics Shanghai Jiao Tong University Shanghai 200030 China Department of PhysicsShanghai Jiao Tong UniversityShanghai 200030China Department of Applied Mathematics Shanghai Jiao Tong University Shanghai 200030 China

We investigate the mechanics ofa new double chain-model of DNA. The model consists of two long elastic homogeneous strands (or rods), which represent two polynucleotide chains of the DNA molecule, connected with each other by an elastic membrane (or some linear springs) representing the hydrogen bonds between the base pairs of the two chains. The nonlinear dynamical equations are derived and some solitary wave solutions are discussed. By the way,our model can be regarded as the mechanical model of cubic nonlinear Klein-Gordon equation and 4-field equation.

关键词： double chain-model of DNA, nonlinear dynamics, solitary wave solutions

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