中能强子－核物理的现状与问题

中能强子与核的散射研究发现,４００ＭｅＶ以上似乎普遍存在着截面理论值偏低的现象,例如,质子－核（ＰＡ）散射、π介子－核（πＡ）散射、ｋ分子－核（ｋＡ）散射的微分戳面传统理论值比实验结果约低２０％．引入相对论动力学可使ＰＡ散射理论结果大为改善。然而,在核子层次上的各种修正对介子－核散射的理论结果改善甚小．人们正在从更深入的非核子自由度寻找原因. Traditional theoretical investigations of the hadron-scattering cross sections ina wide range of nuclei in the intermediate-energy region (above 400MeV) have revealed obvious discrepancies with the existing experimental data. It is about 20% lower than the datafor hadronic probes such as proton,pion and kaon. For proton-nucleus sacattering, an agreement with experiment may significantly be improved by introduction of relativistic dynamices. For meson probes, however...     

逆运动学弹性共振散射方法在非束缚核结构研究中的应用

简要介绍了近几年发展起来的厚靶逆运动学弹性共振散射方法在非稳定核结构测量中的应用。它是研究非束缚态核结构的实验方法之一。通过测量反冲轻核的激发函数，提取共振态的能量、自旋宇称和衰变宽度等。主要用于研究非稳定核素的结构、核天体物理中相关核的阈能共振态的能级参数测量等。The method of elastic resonance scattering in inverse kinematics, which was progressed in recent years, is briefly introduced. It is a novel experimental technique to perform meaningful experiments under conditions of the very short-lived nuclides and the beam intensities only 1 000 atoms/s. The excitation function of recoil proton has been measured in experiment; the shape of proton energy spectrum can be also used to uniquely deter- mine the energy of resonant states, spin-parity, partial decay width and spectroscopic factors of the states. This method is mainly used in the investigation of unstable nuclei and the level parameters measurement of near threshold resonant state of the nuclear astrophysics related nuclei.     

超重核合成截面计算中几个问题的探讨

讨论了超重核形成截面计算中的耦合道效应、壳效应的阻尼效应、能级密度的集体运动增强因子以及蒸发残余核的自旋分布等几个重要问题,并给出相应的实验结果.因这些因素都可能对截面有数量级的影响,正确处理与否直接关系到超重核合成截面理论预言的可靠性. .Several important aspects in the cross section calculations for the synthesis of superheavy nuclei have been inquired. They are the effects of the coupled channels, the damping of shell correction energy, the collective enhancements in the level density and the spin distributions of evaporation residues. The channel coupling of relative motion with internal degrees of freedom will enhance significantly the capture cross section at sub barrier energies. However, recent measurements of spin distributions for ...     

超核物理学进展

简要评述超核物理学近几年的发展,包括常规超核和非常规超核两个方面.对于包含通常超子的常规超核,重点介绍近来在日本KEK完成的一批超核实验及其理论分析.对其中关于超子杂质效应和超子平均自由路程等实验测量结果进行了理论分析,得到一些有意义的结果.并对奇异数为S=-2的Ξ超核的结构和性质进行了若干研究.对于包含C夸克或B夸克的其他味超核,以及可能的包含pentaquark的θ+超核也做了适当的介绍. Progress and recent status of experimental and theoretical investigations on hypernuclear physics are briefly reviewed, including conventional hypernuclear physics and unconventional hypernuclear physics. We introduce the recent progress of hypernuclear experiments in KEK, Japan and the studies of fine structure in γ-ray spectroscopy of Λ hypernuclei. The spin-flip transition between the ground-state spin doublet of light hypernuclei has been observed and the transition energy provides important..     

关于93Mo中21/2+晕阱的来源(英文)

本研究通过壳模型计算研究了N=51的同中子素91Zr、93Mo和95Ru中高自旋晕态21/2+的同核异能态现象。计算发现,低角动量的p_1/2轨道上的质子是仅在93Mo中存在21/2+晕阱的主要原因。同时,本工作还研究了N=52的同中子素92Zr、94Mo和96Ru中10₁+-12₁+能级结构的系统性,发现94Mo中的10₁+-12₁+能级间隙相对最小,考虑到与93Mo的17/2₁+-21/2₁+能级相似的组态,这一结果为93Mo中出现21/2+晕阱提供了补充性的论证。Isomerism of the high-spin yrast 21/2+ states of the N=51 isotones 91Zr, 93Mo and 95Ru has been investigated using the shell model calculations. It is found that the low-j πp_1/2 is responsible for the only yrast trap in 93Mo. In addition, the relatively smaller 10₁+-12₁+ level spacing in 94Mo has been found by investigating the systematics of the 10₁+-12₁+ level structures in the N=52 isotones 92Zr, 94Mo and 96Ru. This result provides a supplementary argument to the origin of the 21/2+ yrast trap in 93Mo from the viewpoint of the similarity between the configurations of 10₁+-12₁+ states in 94Mo and those of 17/2₁+-21/2₁+ states in 93Mo.     

中能强子—核物理的现状与问题

中能强子与核的散射研究发现，400MeV以上似乎普遍存在着截面理论的现象，例如，质子－核（PA）散射、π介子－核（πA）散射、k介子－核（kA）散射的微分截面传统理论值比实验结果约代20％，引入相对论动力学可使PA散射理论结果大为改善，然而，在核子层次上的各种修正对介子－核散射的理论结果改善甚小，人们正在从更深入的非核子自由度寻找原因。     

不同能量下核束缚能的影响

在不同能量下， 利用核束缚能对虚光子四动量的平方项进行修正， 分别计算了Sn核碰撞中核束缚能对反应截面中湮灭项和康普顿散射项及K因子的影响。 结果表明， 核束缚能在小x区域对反应截面中湮灭项和康普顿散射项及K因子的影响明显， 并且能量越低这种影响越显著， 随着x2增大影响逐渐消失。 We made a revision of square of virtual photon four momentum by means of using nuclear bin ding energy formula in different energy， and we also made an accurate calculation for the effect of nuclear binding energy on K factor and Compton term and annihilate term in the Drell Yan process of the Sn Sn collision. The outcome indicates that the effect of nuclear binding energy on the annihilate term and the Compton term is marked in little x region and the effect will become more obvious with decrease of the energy and come to disappear with increase of the x.     

Squeezed back-to-back correlations of K~+K~- in d+Au collisions at sNN~(1/2)=200 GeV and Au+Au collisions at sNN~(1/2)=62.4 GeV

We investigate the squeezed back-to-back correlations(BBC) of K~+K~-, caused by the mass modification of particles in the dense medium formed in d + Au collisions at sNN~(1/2)= 200 GeV and Au + Au collisions at sNN~(1/2)= 62.4 GeV. Considering that some kaons may not be affected by the medium, we further study the BBC functions of K~+K~-when parts of all kaons have a mass-shift. Our results indicate that the BBC functions of K~+K~-can be observed when only ～10% of all kaons have a mass-shift in d + Au collisions at sNN~(1/2) = 200 GeV and the peripheral collisions of Au + Au at sNN~(1/2)= 62.4 GeV. Since the BBC function is caused by the mass-shift due to the interactions between the particle and the medium, the successful detection of the BBC function indirectly marks that the dense medium has formed in these collision systems. We suggest the experimental measurement of the BBC function of K~+K~- in d + Au collisions at sNN~(1/2) = 200 GeV and peripheral collisions of Au + Au at sNN~(1/2) = 62.4 GeV.     

核物理中的π介子

在强子层次上,原子核或强子物质的基本组元是核子和介子.弄清这些强子的结构,并由基本原理出发研究它们的性质,是当代核物理的重要课题.在各种介子中,π介子是最轻且最重要的介子.关于自由空间中π介子的结构与性质、核介质内π介子的性质、π 核子相互作用与π 核相互作用等问题,始终受到相当多的关注.π介子在核物理中的作用直接联系着手征对称性,汤川秀树关于π介子的最初概念已经大大发展了.有清楚的实验证据表明,核内存在π介子的集体模式,这种集体模式与以前观测到的所有核集体运动模式截然不同.拟对π 核物理的研究现状及值得进一步研究的主要问题予以简要评述. At the hadronic level, nucleons and mesons are constituents of nuclei and hadronic matter. Understanding the structures of hadrons, finding the physics of how the properties of these particles arise from the first principle, are major interests in modern nuclear physics. Among mesons, the lightest and most important one is certainly the pion, thus it is no accident that its structure, properties (both in free space and in nuclear matter) and interactions with nucleons and nuclei have gotten considerable ...     

超重核合成中的靶核形变效应

利用额外推力模型研究了48Ca+238U超重核合成过程中的靶核形变效应.计算表明,在近垒和垒下能区,靶核形变使超重核合成截面明显增强.对于48Ca+238U反应,由于靶核形变蒸发残余截面增大了几倍.同时与球形靶核相比,形变靶核时蒸发残余激发函数的峰位移向较低能量.Effects of target deformation on the synthesis of superheavy nucleus~(283)112 are investigated in the framework of extra-push model. Our results show that the cross sections of the 3n evaporation residue in the~(48)Ca+~(238)U reaction for the case of β_2=0.275 are several times larger than those of β_2=0. Meanwhile, the peak position of ER excitation function in the case of deformed target is shifted to the lower energy as compared to the one of spherical target.     

The effect of sound level on perception of reproduced soundscapes

The aim of this work was to investigate the perception of soundscape reproduced by an ambisonic reproduction system on a horizontal plane, how the experience of space affected the perception of soundscape reproduction, and how the sound level adjustment on soundscape reproduction affected the perception of soundscape compared with actual conditions. There were three experiments conducted: a soundwalk in situ in Manchester (United Kingdom) city centre, listening tests in Salford (United Kingdom), and listening tests in Bandung (Indonesia). The listening tests used material recorded from four locations on the soundwalk route in Manchester. The Salford listening tests were performed at the in-situ measured sound level, and the participants were asked to adjust the sound level to the level that represents actual locations. The listening test in Bandung was conducted to understand the effect of participants who never come to the actual location to the perception of soundscape and the sound level adjustment. The listening tests in Bandung were conducted at the in situ sound level, at 9.5 dB below the in situ sound level (based on the preference sound level from the experiment in Salford), and the participants were also requested to adjust the sound level to the level that represents the actual space (to examine the consistency with the experiment in Salford). In each case, soundscape perception was measured on 19 semantic differential scales. Analysis of the semantic differential results showed that the ambisonic reproduction produced a similar subjective experience to the in situ soundwalk when the reproduction sound level was 9.5 dB lower than the actual sound level in situ. Reproduction at the actual sound level in situ produced a different dimensional space. The study shows that the sound level adjustment of soundscape reproduction in laboratory experiment produces more ecologically valid results compared to the reproduction at the actual sound level in situ.     

光泵亚毫米波激光的理论模型及计算方法(Ⅱ)--多能级分子系统的激光增益系数

为了便于对光泵亚毫米波激光进行理论计算,从量子系统的密度矩阵方程出发,分别详细推导了三能级和四能级分子系统的激光增益系数表达方式以及多组独立三能级系统的增益迭加原理.     

Effect of ambient noise on the vocal output and the preferred listening level of conversational speech

The effect of ambient noise on vocal output and the preferred listening level of conversational speech was investigated under conditions typical of everyday speech communication. For a speaker-listener distance of 1 m, vocal output and the preferred listening level in quiet were both about 50 dB(A). Deviations from this value were observed when the noise level exceeded a level of about 40 dB(A). The regression lines for the data points above this level showed a 3 dB rise for a 10 dB rise in noise level. The experiments further suggest that both speaker and listener (when the latter is able to control the playback level of recorded speech) try to compensate for the noise interference by raising the level of speech in order to keep the (subjective) loudness of speech in noise equal to the loudness of speech in quiet.     

基于发射光谱的DF激光器光腔温度与粒子数分布

 建立了谱线增益系数与温度、粒子数分布之间及谱线增益系数与谱线强度之间的关系式,对一台燃烧驱动DF激光器的发射光谱进行了测量,利用发射光谱数据计算得到光腔温度为381.4 K,分布在振动态能级1与0,振动能级2与1,振动能级3与2的粒子数之比分别为0.60～0.62, 0.676 4, 0.71～0.74。     

推进剂用超声液位仪

一类发射体的推进剂具有剧毒,强腐蚀,易挥发,易燃易等特点,一般贮存在密封容器中,如运用通常的接触式仪器对其储罐中的液位进行检测,则仪器使用寿命很短,本文介绍了运输,贮存容器中的液位,能进行非接触式精确测量超声液位仪。     

基于高帽变换算法的液位检测技术的研究

将数学形态学中的高帽变换算法应用于液位高度的检测之中。利用形态学高帽变换,并选用大结构元素,对具有复杂背景的比色皿中的液位图像和分层液位图像进行处理,实现了液位高度的快速准确检测。实验结果表明,该方法适用于医学生化分析仪比色皿中样品液位高度的检测,其原理也可以用于其他工业装置中的液位高度检测。     

Phase modulated gray-scale data pages for digital holographic data storage

We propose a method for gray level holographic digital data storage by using three-gray levels in the phase mode. Gray level data pages are displayed on a SLM operating in the phase mode to obtain a homogenized Fourier spectrum by suppressing the extremely high intensity DC component in the Fourier spectrum of conventional amplitude based binary/gray level data pages. Holographic interferometry has been used to recover the gray level amplitude data page from phase data page. Numerical simulation results are presented for three-gray level data pages. Fourier plane homogeneity, bit-error-rate, storage density, phase modulation error of the SLM, and misalignment tolerances are investigated through computer modeling. A comparison of the present method with the amplitude-modulated gray level case with and without using a phase mask in conjunction with the data page is carried out. An experimental demonstration of the proposed three-gray level phase data page method is also presented.     

The effect of carrier level on tuning in amplitude-modulation masking

The effect of carrier level on tuning in modulation masking was investigated for noise and tonal carriers. Bandwidths of the modulation filters, estimated from the masked detection thresholds using an envelope power spectrum model, were independent of level for the noise carrier but seemed to decrease with increasing level for the tonal carrier. However, the apparently sharper tuning could be explained by increased modulation sensitivity and modulation dynamic range with increasing level rather than improved modulation-frequency selectivity. Consistent with this interpretation, the addition of a high-pass noise with a level adjusted to maintain the same threshold for the detection of the signal modulation for each carrier level used eliminated the effect of level on tuning. Overall, modulation filters estimated from psychophysical data do not depend on level in contrast to the modulation transfer functions obtained from neural recordings in the inferior colliculus in physiological studies. The results highlight differences between the characteristics of modulation processing obtained from neural data and perception. The discrepancies indicate the need for further investigation into physiological correlates of tuning in modulation processing.     

Level mixing resonances on oriented nuclei

The level crossing and level mixing resonance methods have been developed in order to enable the measurement of quadrupole interaction frequencies of nuclei with lifetimes between microseconds and minutes in solids. Both methods are shown to be better suited for application 1n this lifetime region than the existing ones. Only the level mixing resonance method can be applied to nuclei with lifetimes up to several minutes. A review of our level crossing and level mixing experiments is also given in this paper.     

Development of the liquid level meters for the PandaX dark matter detector

The two-phase xenon detector is at the frontier of dark matter direct search. This kind of detector uses liquid xenon as the sensitive target and is operated in two-phase (liquid/gas) mode, where the liquid level needs to be monitored and controlled in sub-millimeter precision. In this paper, we present a detailed design and study of two kinds of level meters for the PandaX dark matter detector. The long level meter is used to monitor the overall liquid level while short level meters are used to monitor the inclination of the detector. These level meters are cylindrical capacitors that are custom-made from two concentric metal tubes. Their capacitance values are read out by a universal transducer interface chip and are recorded by the PandaX slow control system. We present the developments that lead to level meters with long-term stability and sub-millimeter precision. Fluctuations (standard deviations) of less than 0.02 mm for the short level meters and less than 0.2 mm for the long level meter were achieved during a few days of test operation.