有限温度下的K介子凝聚

我们把Brown等讨论在零温时K介子凝聚的工作推广到有限温度.结果表明温度对于原子核的临界密度影响不大,新物质相有可能在重离子反应中形成.     

Spectral property and its shape transition on ^72-84Kr isotopes in microscopic core plus two-quasiparticle approach

By using a microscopic sdIBM-2 2q.p, approach, the levels of the ground-band, 7-band and partial two-quasi-particle bands for ^72-84Kr isotopes are calculated. The data obtained are in good agreement with the recent experimental results, and successfully reproduce the nuclear shape phase transition of ^72-S4Kr isotopes at zero temperature.The ground-state band is described successfully up to J^π=18^ and Ex=10.0MeV. Based on this model, the aligned requisite minimum energy has been deduced. The theoretical calculations indicate that no distinct change of nuclear states is caused by the abruptly broken pair of a boson, and predict that the first backbending of Kr isotopes may be the result of aligning of two quasi-neutrons in orbit g9/2, which galus the new experimental support of the measurements of g factors in the ^78-86Kr isotopes.     

大学物理学绪论课

自 2 0 0 4年第 4期起 ,本刊拟增加一个新栏目 :特色教案选登 .开辟这个栏目的目的是想进一步加强物理教师间的交流 ,不仅通过教学研究文章交流 ,而且通过教学中实用的教案进行交流 .我们相信 ,不管是谁的教案 ,它总有自己的特色和“闪光点”值得同行们借鉴、学习或引起有益的讨论 .因此 ,我们恳请广大读者关注这个新的栏目 ,提出你的建议和意见 .我们特别欢迎全国各高校的老师们 ,把您的具有一定特色的物理课程的教案向本栏投稿 ,绪论课、讲课、辅导课、讨论课、总结课、实验课等各种类型的教案我们都欢迎 .教案拟采用原讲稿的版式 (powerpoint版式或word版式等 )刊登 ,这样做也可以节省投稿者的时间     

走近纳米科技

 纳米科技于20世纪70年代兴起,进入21世纪越来越被大家耳熟。纳米科技在促进科技进步,提高社会文明程度,改善人类生存质量,更新对物质世界的认知及观念上扮演了举足轻重的角色。纳米是长度单位。一纳米为一米的十亿分之一,如果你的拇指指甲盖宽14毫米,这个比例就相当于拇指指甲盖宽度与地球直径间的比例。纳米科技所接触、研究、开发的是100纳米～0.1纳米范围内物质的性质和应用。一个分子或一个原子大小的数量级大致在10纳米。因此,纳米科技也可以说是在分子水平上观察、分析、研究物质的物理、化学性质并加以开发利用。     

美与天文学革命

 著名天文学家陈建生在一次报告中,曾深情地吟诵:“宇宙是美丽的,艺术家感受它,是因为它很美;诗人感受它,是因为它很深邃;科学家感受它,是因为它能让人施展才华……”的确,星空庄严而又绚丽,神秘而又和谐,令人陶醉、令人神往。仰望星空,常常会引起我们无尽的遐想和无限的激情,一种探讨宇宙奥秘的欲望会油然而生。爱因斯坦认为,科学家从事科学探索的动机有三种类型,一种人爱好科学是因为科学研究给他们以超乎常人智力的快感,科学是他们自己的特殊娱乐,他们在这种娱乐中寻求生动活泼的经验和雄心壮志的满足;第二种人是为了纯功利的目的;第三种人,按爱因斯坦的看法,是素养极高的科学     

超短脉冲超强激光与固体靶相互作用中高能离子的产生

 用2D3V PIC粒子模拟方法得到了超短脉冲超强激光与固体靶相互作用中高能离子产生的图像，并对其机理进行了研究。在靶前后表面都观察到了高能离子的产生，并诊断了离子能谱。模拟结果表明，在靶前表面所产生的高能离子，角分布较大，在向靶内输运过程中会损失能量；在靶后表面产生的高能离子，定向性很好，能获得很高的能量。模拟得到的离子能量和实验观测结果在量级上相符。     

Multiple Scattering Effects of Ag Particles in Random Ag-SiN Film

A layer of 40nm-thick Ag-SiN film with Ag nano-particles embedded and distributed randomly in the SiN thin film were deposited by the method of radiant-frequency magnetron sputtering. Specimens orderly comprising a random Ag-SiN film and an optical phase change recording layer were exposed to a focused laser beam with wavelength of 69Ohm. It is shown that, with a random Ag-SiN layer deposited above the recording layer. Calculation by the finite difference time domain method of a 4Ohm-thick SiN film under a Gaussian beam irradiation has been carried out to simulate the near-field distribution in the film, which showed a huge local near-field intensity enhancement of about 200 times if small Ag particles with diameter of 6 nm were modelled inthe SiN film in the central region of the in cident laser spot.     

Theoretical Calculation of Rotational Bands of ^179Pt in the Particle-Triaxial-Rotor Model

Theoretical calculations have been performed for nucleus ^179Pt in the particle-triaxial-rotor model with variable moment of inertia. The obtained energy spectrum agrees with the experimental data quite well. The calculated results indicate that the bands 1/2^- and 7/2^ are triaxial deformation bands and originate mainly from the v[521]1/2^- and v[633]7/2^ configurations respectively.     

Multi-Partite EPR Entangled State Representation for Continuous Variables and Its Application in Squeezing Theory

By extending the Einstein-Podolsky-Rosen (EPR) bipartite entanglement to an n-partite case, we construct the common eigenstate of the n-partite total coordinate and relative momenta for the continuous variables. The entanglement property of the state is shown. The classical dilation transform of variables in such a state induces a new n-mode squeezing operator related to an n-mode bosonic operator realization of SU(1,1) Lie algebra.     

Theoretical Study on the Rotational Bands and Shape Coexistence of^179，181，183Au in the Particle-Triaxial-Rotor Model

We perform a series of theoretical calculations and investigation for nuclei 179，181，183Au in the particle-triaxialrotor model with variable moment of inertia. The calculated energy spectra in^179,181,183Au agree well with the experimental data globally. The obtained results indicate that the nuclei^179,181,183Au have prolate deformation and involve shape coexistence with different deformation parameters in different bands. The main configuration of bands 1, 2, 3 and 5 in these nuclei are identified as [541]1/2^- (πh9/2, α = 1/2), [541]1/2- (πh9/2, α= -1/2),[530] 1/2- (πf7/2) and [660] 1/2^ (πi13/2), respectively.