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.     

Revealing pion and kaon structure via generalised parton distributions

Clear windows onto emergent hadron mass(EHM)and modulations thereof by Higgs boson interactions are provided by observable measures of pion and kaon structure,many of which are accessible via generalised parton distributions(GPDs).Beginning with algebraic GPD Ans?tze,constrained entirely by hadron-scaleπand K valence-parton distribution functions(DFs),in whose forms both EHM and Higgs boson influences are manifest,numerous illustrations are provided.They include the properties of electromagnetic form factors,impact parameter space GPDs,gravitational form factors and associated pressure profiles,and the character and consequences of allorders evolution.The analyses predict that mass-squared gravitational form factors are stiffer than electromagnetic form factors;reveal that K pressure profiles are tighter than profiles,with both mesons sustaining near-core pressures at magnitudes similar to that expected at the core of neutron stars;deliver parameter-free predictions for and K valence,glue,and sea GPDs at the resolving scale l=2GeV;and predict that at this scale the fraction of meson mass-squared carried by glue and sea combined matches that lodged with the valence degrees-of-freedom,with a similar statement holding for mass-squared radii.     

Phase relations in the ZnO-V2O5-K2O system

The subsolidus phase relations of a ZnO-V 2 O 5-K 2 O system are investigated by X-ray powder diffraction.There is 1 ternary compound,11 binary compounds and 14 three-phase regions in this system.The phase diagrams of V 2 O 5 K 2 O with the K 2 O content ranging from 0 to 71 mol% and pseudo-binary system of ZnO-K 2 ZnV 2 O 7 are also studied by X-ray powder diffraction and differential thermal analysis methods.     

Lax pair and vector semi-rational nonautonomous rogue waves for a coupled time-dependent coefficient fourth-order nonlinear Schrodinger system in an inhomogeneous optical fiber

Optical fibers are seen in the optical sensing and optical fiber communication. Simultaneous propagation of optical pulses in an inhomogeneous optical fiber is described by a coupled time-dependent coefficient fourth-order nonlinear Schr?dinger system, which is discussed in this paper. For such a system, we work out the Lax pair, Darboux transformation, and corresponding vector semi-rational nonautonomous rogue wave solutions. When the group velocity dispersion(GVD) and fourth-order dispersion(FOD) coefficients are the constants, we exhibit the first-and second-order vector semirational rogue waves which are composed of the four-petalled rogue waves and eye-shaped breathers. Both the width of the rogue wave along the time axis and temporal separation between the adjacent peaks of the breather decrease with the GVD coefficient or FOD coefficient. With the GVD and FOD coefficients as the linear, cosine, and exponential functions, we respectively present the first-and second-order periodic vector semi-rational rogue waves, first-and second-order asymmetry vector semi-rational rogue waves, and interactions between the eye-shaped breathers and the composite rogue waves.     

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。     

Gravitational collapse with standard and dark energy in the teleparallel equivalent of general relativity

A perfect fluid with self-similarity of the second kind is studied within the framework of the teleparallel equivalent of general relativity(TEGR).A spacetime which is not asymptotically flat is derived.The energy conditions of this spacetime are studied.It is shown that after some time the strong energy condition is not enough to satisfy showing a transition from standard matter to dark energy.The singularities of this solution are discussed.     

Breakdown voltage model and structure realization of a thin silicon layer with linear variable doping on a silicon on insulator high voltage device with multiple step field plates

Based on the theoretical and experimental investigation of a thin silicon layer(TSL) with linear variable doping(LVD) and further research on the TSL LVD with a multiple step field plate(MSFP),a breakdown voltage(BV) model is proposed and experimentally verified in this paper.With the two-dimensional Poisson equation of the silicon on insulator(SOI) device,the lateral electric field in drift region of the thin silicon layer is assumed to be constant.For the SOI device with LVD in the thin silicon layer,the dependence of the BV on impurity concentration under the drain is investigated by an enhanced dielectric layer field(ENDIF),from which the reduced surface field(RESURF) condition is deduced.The drain in the centre of the device has a good self-isolation effect,but the problem of the high voltage interconnection(HVI) line will become serious.The two step field plates including the source field plate and gate field plate can be adopted to shield the HVI adverse effect on the device.Based on this model,the TSL LVD SOI n-channel lateral double-diffused MOSFET(nLDMOS) with MSFP is realized.The experimental breakdown voltage(BV) and specific on-resistance(R on,sp) of the TSL LVD SOI device are 694 V and 21.3 ·mm 2 with a drift region length of 60 μm,buried oxide layer of 3 μm,and silicon layer of 0.15 μm,respectively.     

A new complex variable element-free Galerkin method for two-dimensional potential problems

In this paper, based on the element-free Galerkin (EFG) method and the improved complex variable moving least- square (ICVMLS) approximation, a new meshless method, which is the improved complex variable element-free Galerkin (ICVEFG) method for two-dimensional potential problems, is presented. In the method, the integral weak form of control equations is employed, and the Lagrange multiplier is used to apply the essential boundary conditions. Then the corresponding formulas of the ICVEFG method for two-dimensional potential problems are obtained. Compared with the complex variable moving least-square (CVMLS) approximation proposed by Cheng, the functional in the ICVMLS approximation has an explicit physical meaning. Furthermore, the ICVEFG method has greater computational precision and efficiency. Three numerical examples are given to show the validity of the proposed method.     

Phase properties of odd and even circular states

Phase properties of the even and odd circular states are studied within the Hermitian phase formalism of Pegg and Barnett. Exact analytical formulas for the distribution function and the variance of the phase operator are obtained and used to examine whether or not the even and odd circular states exhibit photon-number squeezing and phase squeezing.     

Nanofabrication of 50 nm zone plates through e-beam lithography with local proximity effect correction for x-ray imaging

High resolution Fresnel zone plates for nanoscale three-dimensional imaging of materials by both soft and hard x-rays are increasingly needed by the broad applications in nanoscience and nanotechnology.When the outmost zone-width is shrinking down to 50 nm or even below,patterning the zone plates with high aspect ratio by electron beam lithography still remains a challenge because of the proximity effect.The uneven charge distribution in the exposed resist is still frequently observed even after standard proximity effect correction(PEC),because of the large variety in the line width.This work develops a new strategy,nicknamed as local proximity effect correction(LPEC),efficiently modifying the deposited energy over the whole zone plate on the top of proximity effect correction.By this way,50 nm zone plates with the aspect ratio from 4:1 up to 15:1 and the duty cycle close to 0.5 have been fabricated.Their imaging capability in soft(1.3 keV)and hard(9 keV)x-ray,respectively,has been demonstrated in Shanghai Synchrotron Radiation Facility(SSRF)with the resolution of 50 nm.The local proximity effect correction developed in this work should also be generally significant for the generation of zone plates with high resolutions beyond 50 nm.     

“绿色”液体激光介质的非线性光学特性研究

利用氧化钕和盐酸为原料制得Nd(phen)2Cl3(三氯二邻菲罗啉合钕),测得其光谱特性并以稀土氧化钕、苯甲酸和邻菲罗啉为原料制得绿色液体激光介质钕离子的配合物——NdB3 phen(三苯甲酸-邻菲罗啉合钕).利用飞秒激光器,采用单光束Z-扫描法研究了NdB3 phen的三阶非线性光学特性.结果表明:当入射飞秒激光脉冲...     

基于全保偏八字腔结构锁模的光纤激光器及其功率放大

采用包层泵浦的全保偏八字腔结构搭建了一种脉宽可调的掺镱锁模光纤激光器,实现了中心波长为1 064nm、重复频率为4.683 MHz、脉冲宽度可调范围为0.8~5ns、对应平均功率范围为74.8~429.7mW的耗散孤子共振方波脉冲输出.腔内无需偏振控制器,仅通过调节泵浦输入即可实现锁模状态的自启动,并能够长时间保持稳定,在剧烈振动条件下亦不会失锁.采用两级光纤放大器进行功率放大,实现了100 W的平均功率输出,峰值功率高达26.68kW.     

利用Zemax分析“猫眼效应”的激光反射特性

利用Zemax镜头设计软件建立了共轴的简化"猫眼效应"反射模型,并结合其强大的物理光学传播分析功能,仿真分析了目标镜头的口径、焦距、焦平面反射元件尺寸、倾斜度等主要参数对"猫眼效应"激光反射特性的影响。仿真分析的结果表明,目标镜头的"猫眼效应"激光反射特性是受目标参数和入射激光特性所共同制约的,对于空中目标来说,其"猫眼效应"的激光反射特性完全可以为激光主动探测所用。     

温度对高功率半导体激光器阵列“smile”的影响

用数值模拟与实验测试相结合的方法,研究了温度对"smile"的影响.利用有限元方法分别模拟计算了半导体激光器芯片键合及工作过程中激光器芯片中的热应力,模拟中假设激光器芯片的弯曲仅由热应力引起;计算结果表明,激光器芯片有源区的热应力随工作温度的升高而减小,由热应力导致的芯片的弯曲随温度升高而减小.实验结果表明,对于具有相同芯片、同一封装形式、同批次的器件,"smile"随温度的升高有增大或减小的趋势,这与封装前裸芯片的弯曲形态及封装热应力的综合作用有关;若封装前裸芯片为相对平直的或凸的,则封装后激光器的"smile"将随温度升高而减小;若封装前裸芯片为凹的,封装后的激光器芯片仍为凹的,则"smile"随温度升高而增大.     

"一把尘埃出激光"--介绍一种新的无序激光器

文章简略地介绍了新型无序激光的发现和确证过程，以及它产生相干光的机制．这种激光器没有腔镜，代替腔镜起作用的是无序介质中的光子囚禁效应．实验并显示了被囚禁的光子在介质中的分布．通过这种机制还可制成一个微米大小的微型激光器。     

966nm半导体激光激发下ErYb：ZBLAN玻璃的上转换特征饱和现象

本文研究了单掺Er和ErYb共掺的ZBLAN玻璃的上转换发光现象,发现了一种新颖的“Er(0.3)Yb(0.5):ZBLAN样品上转换发光强度随激光功率变化的双对数曲线的斜率相对于Er(0.3):ZBLAN样品有明显的降低、但都保持着很好的直线”的这种“特征、饱和现象,它的上转换机制是一种新颖的“扩散－传递”机制：即Yb^3 -Yb^3 间能量扩散和随后的Yb^3 -Er^3 间能量传递。其“特征”饱和现象就是由“Yb^3 -Yb^3 ”间能量扩散导致的。     

Laser Wakefield Acceleration Using Mid-Infrared Laser Pulses

We study a laser wakefield acceleration driven by mid-infrared(mid-IR) laser pulses through two-dimensional particle-in-cell simulations.Since a mid-IR laser pulse can deliver a larger ponderomotive force as compared with the usual 0.8 μm wavelength laser pulse,it is found that electron self-injection into the wake wave occurs at an earlier time,the plasma density threshold for injection becomes lower,and the electron beam charge is substantially enhanced.Meanwhile,our study also shows that quasimonoenergetic electron beams with a narrow energy-spread can be generated by using mid-IR laser pulses.Such a mid-IR laser pulse can provide a feasible method for obtaining a high quality and high charge electron beam.Therefore,the current efforts on constructing mid-IR terawatt laser systems can greatly benefit the laser wakefield acceleration research.