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Probing proton halo of the exotic nucleus ^(28)S by elastic electron scattering

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Science china(physics,Mechanics & Astronomy) 2004年第1期47卷 42-51页

作者： WANG Zaijun1 & ren zhongzhou1’2 1. department of physics, nanjing university, nanjing 210008, china 2. Center of Theoretical Nuclear physics, National Laboratory of Heavy-Ion Accelerator at Lanzhou, Lanzhou 730000, china Correspondence should be addressed to ren zhongzhou (email: zren@*** zren99@***) Received June 16, 2003 department of physics Nanjing University Nanjing 210008 China Center of Theoretical Nuclear physics National Laboratory of Heavy-Ion Accelerator at Lanzhou Lanzhou 730000 China

Elastic electron scattering on the exotic light nucleus 28S is investigated in the plane wave Born approximation. The variation of the squared form factors of 28S with momentum transfer is compared with that of 32S. It is found that the behavior of the form factors near the second minimum (with a moderate momentum transfer) is sensitive to the alteration of the charge density distribution of halo protons in 28S. This indicates that elastic electron scattering can be a good probe of the structure of proton-halo nuclei.

关键词： elastic electron scattering, cross section, form factor, proton-halo nucleus.

Simple Formula of β^+-Decay Half-Lives of Nuclei Far From β-Stable Line

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Communications in Theoretical physics 2007年第12期48卷 1072-1080页

作者： ZHANG Xiao-Ping~1 ren Zhong-Zhou~(1,2)and ZHI Qi-Jun~1~1 department of physics,nanjing university,nanjing 210008,china~2 Center of Theoretical Nuclear physics,National Laboratory of Heavy-Ion Accelerator,Lanzhou 730000,china department of physics Nanjing University Nanjing 210008 China Center of Theoretical Nuclear physics National Laboratory of Heavy-Ion Accelerator Lanzhou 730000 China

We generalize the formula of β^+-decay half-lives [***.C 78 (2006) 014305] to include all availabledata of nuclei far from the β-stable line. Good agreement with experimental data is obtained by taking into accountthe even-odd (e-o) *** is shown that the e-o effect on β^+-deeay half-life is apparent for the allowed β^+-transition,whereas it is not apparent for the first and second forbidden *** demonstrates that the allowed β^+-transitionis more sensitive to the nuclear even-odd effect than the forbidden β^+-*** underlying physics is *** formula can be used to predict the β^+-decay half-lives of the nuclei far from β-*** is useful to experimentalphysicists for analyzing the data of β^+-decay.

关键词： β^+-decay half-lives formula even-odd effect

Effects of different concentrations of nicotinamide on hematopoietic stem cells cultured in vitro

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World Journal of Stem Cells 2024年第2期16卷 163-175页

作者： Yan ren Yan-ni Cui Hong-Wei Wang The Second Clinical Medical College Shanxi Medical UniversityTaiyuan 030001Shanxi ProvinceChina department of Hematology The Second Hospital of Shanxi Medical UniversityTaiyuan 030001Shanxi ProvinceChina department of Hematology Key Laboratory of Molecular Diagnosis and Treatment of Blood Diseases in Shanxi ProvinceTaiyuan 030001Shanxi ProvinceChina

BACKGROUND In vitro expansion to increase numbers of hematopoietic stem cells(HSCs)in cord blood could improve clinical efficacy of this vital ***(NAM)can promote HSC expansion ex vivo,but its effect on hematopoietic stem and progenitor cells(HSPCs,CD34^(+)CD38)and functional subtypes of HSCs-shortterm repopulating HSCs(ST-HSCs,CD34^(+)CD38CD45RACD49f^(+))and long-term repopulating HSCs(LT-HSCs,CD34^(+)CD38CD45RACD49f^(+)CD90^(+))is not yet *** a sirtuin 1(SIRT1)inhibitor,NAM participates in regulating cell adhesion,polarity,migration,proliferation,and ***,SIRT1 exhibits dual effects by promoting or inhibiting differentiation in different tissues or *** propose that the concentration of NAM may influence proliferation,differentiation,and SIRT1 signaling of *** To evaluate the effects and underlying mechanisms of action of different concentrations of NAM on HSC proliferation and *** CD34^(+)cells were purified from umbilical cord blood using MacsCD34 beads,and cultured for 10-12 d in a serum-free medium supplemented with cytokines,with different concentrations of NAM added according to experimental *** cytometry was used to detect phenotype,cell cycle distribution,and apoptosis of the cultured ***-time polymerase chain reaction was used to detect the transcription levels of target genes encoding stemness-related factors,che mokines,components of hypoxia pathways,and antioxidant ***-dihydro-fluorescein diacetate probes were used to evaluate intracellular production of reactive oxygen species(ROS).Determination of the effect of different culture conditions on the balance of cytokine by cytometric bead *** Compared with the control group,the proportion and expansion folds of HSPCs(CD34^(+)CD38)incubated with 5 mmol/L or 10 mmol/L NAM were significantly increased(all Pnificantly

关键词： Hematopoietic stem cells nicotinamide Concentration Proliferation Differentiation Sirtuin 1

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Science china Chemistry 2004年第6期47卷 466-479页

作者： SONG Huajie1,2, XIAO Heming1 & DONG Haishan2 1. department of Chemistry, nanjing university of Science and Technology, nanjing 210094, china 2. Institute of Chemical Materials, china Academy of Engineering physics, Mianyang 621900, china department of Chemistry Nanjing University of Science and Technology Nanjing China Institute of Chemical Materials China Academy of Engineering Physics Mianyang China

The symmetry-adapted perturbation theory (SAPT) that has the ability in decompo- sition of the total interaction energy into physically meaningful components is used to provide a more fundamental understanding of intermolecular forces. This work was motivated by the diffi- culty of standard SAPT in computing the intermolecular interactions for large energetic dimer systems. SAPT based on Kohn-Sham orbitals (SAPT(DFT)) proves computationally efficient for these large systems, but has been shown to perform poorly for interaction energy components. The deficiencies of SAPT(DFT) result from wrong asymptotical behaviors of commonly used exchange-correlation potentials. To remove the deficiencies, two asymptotic corrections by means of van Leeuwen and Baerends (LB) model potential and Fermi-Amaldi (FA) type potential were applied into three small test systems comprising He2, HF2 and (N2)2 and a set of larger ni- tramide dimers at several separations. The results showed that when utilizing newly developed frequency-dependent density susceptibilities (FDDS) technique for computing dispersion energy, the FA asymptotic correction is very effective to circumvent these deficiencies in SAPT(DFT) and yields a good accuracy over the LB correction. The FA corrected SAPT(DFT) approach is capa- ble of correctly predicting all the quantitative trends in binding energies for all test cases and substantially reduces computational cost as compared with the standard SAPT calculations. The successful application of the approach to nitramide dimer demonstrates that it potentially pro- vides a good means to calculate accurately intermolecular forces in larger system such as en- ergetic systems.

关键词： intermolecular interaction, density functional theory (DFT), symmetry adapted perturbation theory (SAPT), asymptotic correction, frequency-dependent density susceptibilities (FDDS).

Quantum statistical entropy corresponding to cosmic horizon in five-dimensional spacetime

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Science china(physics,Mechanics & Astronomy) 2008年第2期51卷 140-146页

作者： ZHAO ren1,2 & ZHANG ShengLi1 1 department of Applied physics, Xi’an Jiaotong university, Xi’an 710049, china 2 department of physics, Shanxi Datong university, Datong 037009, china department of Applied physics Xi’an Jiaotong University Xi’an China department of physics Shanxi Datong University Datong China

The generalized uncertainty relation is introduced to calculate the quantum statis-tical entropy corresponding to cosmic horizon. By using the new equation of state density motivated by the generalized uncertainty relation, we discuss entropies of Bose field and Fermi field on the background of five-dimensional spacetime. In our calculation, we need not introduce cutoff. There is no divergent logarithmic term in the original brick-wall method. And it is obtained that the quantum statistical en-tropy corresponding to cosmic horizon is proportional to the area of the horizon. Further it is shown that the entropy corresponding to cosmic horizon is the entropy of quantum state on the surface of horizon. The black hole's entropy is the intrinsic property of the black hole. The entropy is a quantum effect. In our calculation, by using the quantum statistical method, we obtain the partition function of Bose field and Fermi field on the background of five-dimensional spacetime. We provide a way to study the quantum statistical entropy corresponding to cosmic horizon in the higher-dimensional spacetime.

关键词： quantum statistical entropy generalized uncertainty relation high-dimensional spacetime

An iterative wavefront sensing algorithm for high-contrast imaging systems

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Research in Astronomy and Astrophysics 2011年第2期11卷 198-204页

作者： Jiang-Pei Dou 1,2,De-Qing ren 1,2,3 and Yong-Tian Zhu 1,2 1 National Astronomical Observatories/nanjing Institute of Astronomical Optics & Technology,Chinese Academy of Sciences,nanjing 210042,china 2 Key Laboratory of Astronomical Optics & Technology,nanjing Institute of Astronomical Optics & Technology,Chinese Academy of Sciences,nanjing 210042,china 3 physics & Astronomy department,California State university Northridge,18111 Nordhoff Street,Northridge,California 91330-8268,USA National Astronomical Observatories / nanjing Institute of Astronomical Optics & Technology Chinese Academy of Sciences Nanjing 210042 China Key Laboratory of Astronomical Optics & Technology Nanjing Institute of Astronomical Optics & Technology Chinese Academy of Sciences Nanjing 210042 China physics & Astronomy department California State University Northridge 18111 Nordhoff Street Northridge California 91330-8268 USA

Wavefront sensing from multiple focal plane images is a promising technique for high-contrast imaging ***,the wavefront error of an optics system can be properly reconstructed only when it is very *** paper presents an iterative optimization algorithm for the direct measurement of large static wavefront errors from only one focal plane *** first measure the intensity of the pupil image to get the pupil function of the system and acquire the aberrated image on the focal plane with a phase error that will be *** we induce a dynamic phase on the tested pupil function and calculate the associated intensity of the reconstructed image on the focal *** algorithm will then try to minimize the intensity difference between the reconstructed image and the aberrated test image in the focal plane,where the induced phase is a variable of the optimization *** simulation shows that the wavefront of an optical system can theoretically be reconstructed with high precision,which indicates that such an iterative algorithm may be an effective way to perform wavefront sensing for high-contrast imaging systems.

关键词： techniques: image processing -- methods: numerical -- planetarysystems

Toughened (Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B_(2)–SiC composites fabricated by one-step reactive sintering with a unique SiB_(6) additive

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Journal of Advanced Ceramics 2024年第1期13卷 86-100页

作者： Wei Hao Xinzhe Lu Ling Li Tao Wang Guoliang ren Huangyue Cai Xiaofeng Zhao Dongyun Wang Na ni Zhejiang Provincial Key Laboratory of Urban Rail Transit Intelligent Operation and Maintenance Technology&Equipment Zhejiang Normal UniversityZhejiang 321004China Key Lab of Education Ministry for Power Machinery and Engineering School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China

High-entropy diboride has been arousing considerable interest in recent ***,the low toughness and damage tolerance limit its applications as ultra-high-temperature structural *** we report that a unique SiB_(6) additive has been first incorporated as boron and silicon sources to fabricate a high-entropy boride(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B_(2)–SiC composite though one-step boro/carbothermal reduction reactive sintering.A synergetic effect of high-entropy sluggish diffusion and SiC secondary phase retarded the grain growth of the(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B_(2)–51SiC *** small grain size was beneficial to shorten the diffusion path for mass transport,thereby enhancing the relative density to~99.3%.These results in an increase of fracture toughness from~5.2 in HEBS-1900 to~7.7 MPa·m^(1/2) in HEBS-2000,which corresponded to a large improvement of 48%.The improvement was attributed to a mixed mode of intergranular and transgranular cracking for offering effective pinning in crack propagation,resulting from balanced grain boundary strength collectively affected by improved densification,solid solution strengthening,and incorporation of SiC secondary phase.

关键词： high-entropy diboride silicon hexaboride boro/carbothermal reduction reactive sintering fracture toughness

Stochastic parallel gradient descent based adaptive optics used for a high contrast imaging coronagraph

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Research in Astronomy and Astrophysics 2011年第8期11卷 997-1002页

作者： Bing Dong De-Qing ren Xi Zhang physics ＆ Astronomy department California State University Northridge CA 91330-8268 USA National Astronomical Observatories/nanjing Institute of Astronomical Optics ＆ Technology Chinese Academy of Sciences Nanjing 210042 China

An adaptive optics （AO） system based on a stochastic parallel gradient descent （SPGD） algorithm is proposed to reduce the speckle noises in the optical system of a stellar coronagraph in order to further improve the contrast. The principle of the SPGD algorithm is described briefly and a metric suitable for point source imaging optimization is given. The feasibility and good performance of the SPGD algorithm is demonstrated by an experimental system featured with a 140-actuator deformable mirror and a Hartrnann-Shark wavefront sensor. Then the SPGD based AO is applied to a liquid crystal array （LCA） based coronagraph to improve the contrast. The LCA can modulate the incoming light to generate a pupil apodization mask of any pattern. A circular stepped pattern is used in our preliminary experiment and the image contrast shows improvement from 10^-3 to 10^-4.5 at an angular distance of 2A/D after being corrected by SPGD based AO.

关键词： instrumentation: adaptive optics -- methods: laboratory -- techniques: image processing coronagraph

Quantum Inequality Bounds for Free Rarita-Schwinger Field in Flat Spacetime

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Communications in Theoretical physics 2006年第7期 87-90页

作者： SHU Wei-Xing,~1 YU Hong-Wei,~2 LI Fei,~1 WU Pu-Xun,~2 and ren Zhong-Zhou~1 ~1department of physics, nanjing university, nanjing 210093. china ~2department of physics, Hunan Normal university, Changsha 410081, china

Although quantum field theory allows the local energy density negative, it also places severe restrictions on the negative energy. One of the restrictions is the quantum energy inequality (QEI), in which the energy density is averaged over time, or space, or over space and time. By now temporal QEIs have been established for various quantum fields, but less work has been done for the spacetime quantum energy inequality. In this paper we deal with the free Rarita-Schwinger field and present a quantum inequality bound on the energy density averaged over space and time. Comparison with the QEI for the Rarita-Schwinger field shows that the lower bound is the same with the QEI. At the same time, we find the quantum inequality for the Rarita-Schwinger field is weaker than those for the scalar and Dirac fields. This fact gives further support to the conjecture that the more freedom the field has, the more easily the field displays negative energy density and the weaker the quantum inequality becomes.

关键词： negative energy density quantum inequality