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     

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.     

Theoretical investigation of band-gap and mode characteristics of anti-resonance guiding photonic crystal fibres

With the full-vector plane-wave method (FVPWM) and the full-vector beam propagation method (FVBPM),the dependences of the band-gap and mode characteristics on material index and cladding structure parameter in antiresonance guiding photonic crystal fibres (ARGPCFs) are sufficiently analysed.An ARGPCF operating in the nearinfrared wavelength is shown.The influences of the high index cylinders,glass interstitial apexes and silica structure on the characteristics of band-gaps and modes are deeply investigated.The equivalent planar waveguide theory is used for analysing such an ARGPCF filled by the isotropic materials,and the resonance and the anti-resonance characteristics can be well predicted.     

Some applications of a new coherent-entangled state in two-mode Fock space

Using the technique of integration within an ordered product of operators,we find a new kind of coherent-entangled state(CES),which exhibits both coherent and entangled state properties.The set of CESs makes up a complete and partly nonorthogonal representation.Using a beam splitter,we propose a simple experimental scheme to produce the CES.Finally,we present some applications of CESs in quantum optics.     

长直组合圆柱面电容器内电势分布的实验研究

对长直组合圆柱面电容器的电势分布进行实验验证。     

环形线电荷的电场分布

给出了圆环形线电荷电场分布的理论公式，并利用计算机计算出其具体分布规律。     

沿轴线的中垂线方向匀速直线运动的电偶极子的电场

本文计算了沿轴线的中垂线方向匀速直线运动的电偶极子的电场.     

带电粒子在径向电场中的电漂移——对一个实验的再认识

本文对文献[1]中的一个问题进行了理论与实验研究，指出了原有解释的不当之处，并采用基于Runge-Kutta-Felhberg算法的Matlab数值方法给出本问题的数值解．     

电场作用下的气泡受力分析

本文在蠕动流近似的基础上分析计算了具有不同介电常数工质的气泡在外电场力作用下的受力状况。计算结果表明电场力的水平分力使气泡沿场强方向伸长,并且液体和气体相对介电常数之比越大的工质所受的电场力越大。从而,沸腾换热过程中外加电场对液体和气体相对介电常数比值较大的工质能够产生更大的影响。     

用▽×Ek=-(e)B/(e)t计算感生电场

本文利用 ×Ek=- B t,对轴对称均变磁场激发的感生电场进行了分析、讨论和计算 .     

不良导体导热系数测定实验中仪表风扇对实验结果的影响

根据对物体冷却规律的分析,并从实验结果比较,指出稳态法测不良导体导热系数实验中,设置散热盘的冷却过程应与其在稳态过程时的强迫对流散热方式保持一致.     

镜象电流选择的唯一性

利用稳恒磁场边值问题解答的唯一性定量和维尔斯特拉斯定理讨论了镜象电流选择的唯一性。     

电容器电容的定义问题

给出并证明了一般情况下电容器电容的计算公式,通过实例说明了公式中各量的意义及应用方法．     

电偶极子与模拟心电图测量

介绍一种利用电偶极子在容积导体中周期性地变化来进行模拟心电图测量的演示实验，说明心电向量概念和心电图的产生原理。