Precision Mass Measurements of Short-lived Nuclides at the Heavy-ion Storage Ring in Lanzhou

Recent commissioning of the Cooler Storage Ring at the Heavy Ion Research Facility in Lanzhou enabled us to conduct high-precision mass measurements at the Institute of Modern Physics in Lanzhou (IMP). In the past few years, mass measurements were performed using the CSRe-based isochronous mass spectrometry employing the fragmentation of the energetic beams of 58Ni, 78Kr, 86Kr, and 112Sn projectiles. Masses of short-lived nuclides on both sides of the stability valley were addressed. Relative mass precision of down to 10−6 ~ 10−7 is routinely achieved. The mass values were used as an input for dedicated nuclear structure and astrophysics studies, providing for instance new insights into the rp-process of nucleosynthesis in X-ray bursts. In this contribution, we briefly review the so far conducted experiments and the main achieved results, as well as outline the plans for future experiments.     

由58Fe 和209Bi 熔合后的相关衰变过程得到的109号元素的证据

本文报导了合成109号元素的实验。用能量为4.95,5.05和5.15MeV/u 的~(58)Fe 束轰击~(209)Bi 靶,研究了全熔合产物衰变模式的特性。总辐照剂量为7×10~(17)粒子。所用的实验方法是:用静电场速度过滤器在飞行过程中分离向前方向成峰的反应产物,经过飞行时间装置后注入到位置灵敏固态探测器中,测量其动能,估算出质量、入射的时间和位置。以所有的出射粒子的能量和时间来记录很有限的反应产物发生级联α粒子和(或)自发裂变的继发衰变。在5.15 MeV/u 时的一个特别的衰变过程是:在5ms 和22ms 先分别发射两个α粒子,最后,在13s 后发生自发裂变。第一个α粒子的动能为11.10±0.04MeV。对各种可能的解释进行了详细的分析,例如纯属偶然的信号相关,转移反应产物的衰变和从能量上看允许的余核蒸发等。最后表明质量数为266的109号元素的同位素、即全熔合后的单中子蒸发道、从统计的观点看是最好的指定。本文同时也讨论了合成新元素的前景。     

Random-injection-based two-channel chaos with enhanced bandwidth and suppressed time-delay signature by mutually coupled lasers: Proposal and numerical analysis

Simultaneous bandwidth(BW) enhancement and time-delay signature(TDS) suppression of chaotic lasing over a wide range of parameters by mutually coupled semiconductor lasers(MCSLs) with random optical injection are proposed and numerically investigated. The influences of system parameters on TDS suppression(characterized by autocorrelation function(ACF) and permutation entropy(PE) around characteristic time) and chaos BW are investigated. The results show that, with the increasing bias current, the ranges of parameters(detuning and injection strength) for the larger BW(> 20 GHz) are broadened considerably, while the parameter range for optimized TDS(< 0.1) is not shrunk obviously.Under optimized parameters, the system can simultaneously achieve two chaos outputs with enhanced BW(> 20 GHz)and perfect TDS suppression. In addition, the system can generate two-channel high-speed truly physical random number sequences at 200 Gbits/s for each channel.     

Brane world black holes in teleparallel theory equivalent to general relativity and their Killing vectors, energy, momentum and angular momentum

The energy-momentum tensor, which is coordinate-independent, is used to calculate energy, momentum and angular momentum of two different tetrad fields. Although, the two tetrad fields reproduce the same space-time their energies are different. Therefore, a regularized expression of the gravitational energy-momentum tensor of the teleparallel equivalent of general relativity (TEGR), is used to make the energies of the two tetrad fields equal. The definition of the gravitational energy-momentum is used to investigate the energy within the external event horizon. The components of angular momentum associated with these space-times are calculated. In spite of using a static space-time, we get a non-zero component of angular momentum! Therefore, we derive the Killing vectors associated with these space-times using the definition of the Lie derivative of a second rank tensor in the framework of the TEGR to make the picture more clear.     

Quantum fluctuation in excited states of mesoscopic LC circuits at finite temperature

We discuss quantum fluctuation in excited states(named thermo number states) of mesoscopic LC circuits at a finite temperature.By introducing the coherent thermo state into the thermo field dynamics pioneered by Umezawa and using the natural representation of thermo squeezing operator we can concisely derive the fluctuation.The result shows that the noise becomes larger when either temperature or the excitation number increases.     

Pressure effect study on the Ⅰ-Ⅴ property of the GaAs-based resonant tunnelling structure by photoluminescence measurement

This paper discusses the Ⅰ-Ⅴ property of the GaAs-based resonant tunnelling structure(RTS) under external uniaxial pressure by photoluminescence studies.Compressive pressure parallel to the [110] direction,whose value is determined by Hooke's law,is imposed on the sample by a helix micrometer.With the increase of the applied external uniaxial compressive pressure,the blue shift and splitting of the luminescence peaks were observed,which have some influence on the I-V curve of RTS from the point of view of the energy gap,and the splitting became more apparent with applied pressure.Full width at half maximum broadening could also be observed.     

圆周运动公式的圆周图示记忆法

匀速圆周运动是曲线运动章节的教学重点．现行高中及中专教材均以两节的篇幅来讨论这种运动．一节是建立匀速圆周运动的概念,引入描述匀速圆周运动快慢的4个量,即周期(T)、频率(v)、角速度(ω)、线速度(v),并讨论这4个量的关系．另一节则从受力的角度讨论圆周运动的向心力及向心加速度．共涉及6个量．由于这6个量之间彼此存在一定的关系,这就使圆周运动具有较多的公式．如果学生能熟练掌握这些公式以及它们之间相互关系的规律,解题就能     

Function projective synchronization between fractional-order chaotic systems and integer-order chaotic systems

This paper investigates the function projective synchronization between fractional-order chaotic systems and integer-order chaotic systems using the stability theory of fractional-order systems. The function projective synchronization between three-dimensional (3D) integer-order Lorenz chaotic system and 3D fractional-order Chen chaotic system are presented to demonstrate the effectiveness of the proposed scheme.     

An ab initio investigation of the low-lying electronic states of BeH

Potential energy curves(PECs) for the ground state(X 2 Σ +) and the four excited electronic states(A 2 Π,B 2 Π,C 2 Σ +,4 Π) of a BeH molecule are calculated using the multi-configuration reference single and double excited configuration interaction(MRCI) approach in combination with the aug-cc-pVTZ basis sets.The calculation covers the internuclear distance ranging from 0.07 nm to 0.70 nm,and the equilibrium bond length R e and the vertical excited energy T e are determined directly.It is evident that the X2Σ+,A2Π,B2Π,C2Σ+ states are bound and 4Π is a repulsive excited state.With the potentials,all of the vibrational levels and inertial rotation constants are predicted when the rotational quantum number J is set to be equal to zero(J = 0) by numerically solving the radial Schr¨odinger equation of nuclear motion.Then the spectroscopic data are obtained including the rotation coupling constant ω e,the anharmonic constant ωexe,the equilibrium rotation constant Be,and the vibration-rotation coupling constant αe.These values are compared with the theoretical and experimental results currently available,showing that they are in agreement with each other.     

Effects of sea surface temperature, cloud radiative and microphysical processes, and diurnal variations on rainfall in equilibrium cloud-resolving model simulations

The effects of sea surface temperature(SST),cloud radiative and microphysical processes,and diurnal variations on rainfall statistics are documented with grid data from the two-dimensional equilibrium cloud-resolving model simulations.For a rain rate of higher than 3 mm.h 1,water vapor convergence prevails.The rainfall amount decreases with the decrease of SST from 29℃ to 27℃,the inclusion of diurnal variation of SST,or the exclusion of microphysical effects of ice clouds and radiative effects of water clouds,which are primarily associated with the decreases in water vapor convergence.However,the amount of rainfall increases with the increase of SST from 29℃ to 31℃,the exclusion of diurnal variation of solar zenith angle,and the exclusion of the radiative effects of ice clouds,which are primarily related to increases in water vapor convergence.For a rain rate of less than 3 mm.h 1,water vapor divergence prevails.Unlike rainfall statistics for rain rates of higher than 3 mm.h 1,the decrease of SST from 29℃ to 27℃ and the exclusion of radiative effects of water clouds in the presence of radiative effects of ice clouds increase the rainfall amount,which corresponds to the suppression in water vapor divergence.The exclusion of microphysical effects of ice clouds decreases the amount of rainfall,which corresponds to the enhancement in water vapor divergence.The amount of rainfall is less sensitive to the increase of SST from 29℃ to 31℃ and to the radiative effects of water clouds in the absence of the radiative effects of ice clouds.     

Matlab在大学物理教学中的辅助应用

以(线性和非线性)谐振子的求解过程为例,分析如何在大学物理的教学过程中引入Matlab计算工具.利用Matlab的符号计算和数值模拟两方面的强大功能,引导学生如何处理基本物理问题,体现了Matlab的可视化和简洁性对大学物理教学的辅助作用,激发学生学习的热情,提高大学物理教学的整体效率和质量.     

开放性大学物理实验与大学生创新项目

开放性大学物理实验作为大学物理实验的改革方向及当代大学物理实验的重要组成部分,在我国大部分高校正在开展,也得到了各高校的重视。大学生创新项目作为高校科技处或者教务处组织的大学生活动,在培养大学生的创新能力方面起到非常重要的作用。本文介绍了开放性大学物理实验的作用与特点、大学生创新项目的人才培养作用,结合我院实际情况,提出了开放性大学物理实验与大学生创新项目的相辅相成作用。本文认为开放性大学物理实验与大学生创新项目结合,可以对两者的发展都起到非常好的促进作用。     

大学物理实验数字化教学改革的探索

将信息技术应用于物理实验教学,不仅可以丰富实验教学的内容,使一些教学内容变得直观、易懂,从而可以有效提高学生的学习兴趣、创新思维和创造能力,是改善物理实验教学的有效途径。通过数字化教学改革及课程建设,我校大学物理实验中心也于2015年被评为天津市示范实验中心。     

大学基础课程实验教学方案设计的研究与实践

本文探讨了大学基础课程实验教学方案设计的内容和方法,并对常见的实验教学方式进行了界定,以我校开设的《物理学实验》为例,对大学基础课程实验教学方案进行了设计,该研究不仅能进一步提高《物理学实验》的教学效果,也为大学基础课程实验教学方案的设计提供了参考与借鉴。     

从高中物理课选修情况看执行大学物理课程教学基本要求的意义

介绍在北京邮电大学新生中进行高中物理课程选修情况的调查统计结果,从中可以看到大学物理课程执行《非物理类理工学科大学物理课程教学基本要求》的必要性.     

衔接视野下大学物理实验教学改革的探索

师范大学教学改革一定要加强与基础教育的衔接.目前师范大学对物理实验课程重视不够、研究不够、与中学脱节,已经影响大学物理实验课程对物理学专业师范生的培养质量.在探索实验教学改革过程中,结合中学物理实验教学现状和大学一年级新生实验能力现状,实施了预备实验教学,树立了课程衔接的理念,并对实施效果进行了分析讨论.     

大学物理课程思政的问卷调查与分析

采用自编的大学物理课程思政问卷,以笔者所带的湖北文理学院正在学习大学物理课程的学生为样本,实施问卷调查.问卷显示,70%左右的学生需要大学物理课程思政,80%左右的学生接受大学物理课程思政线上教学.分析了学生做出这些选择的原因,同时调研了他们对大学物理课程思政有哪些期许.对如何改进大学物理课程思政具有一定的指导意义.     

大学物理研究性实验探索

对笔者在物理实验教学过程中,所指导学生进行的一些具有创新性的研究性实验进行了探索、研究,归纳和总结,对学生进行研究性实验的情况进行了介绍,以供各位同仁师生参考。     

普通物理力学和理论力学的整合

理顺物理类普通物理力学和理论力学的关系,将理论力学中的牛顿力学部分基本上都归入普物力学,加强分析力学部分,并增加非线性力学,改名为分析力学．     

大学物理实验教学与创新

大学物理实验是理工科大学开设的一门必修基础课,是高等教育的重要组成部分。本文指出了传统大学物理实验教学的弊端,增设计划性实验项目,延长开放时间,改善了大学物理实验教学。