弱相互作用费米气体的不稳定性判据

根据由赝势法得到的弱相互作用费米气体的自由能，利用热力学方法研究了无外场时弱相互作用费米气体的稳定性.结果表明，无外场情况下理想费米气体与存在弱排斥相互作用的费米气体是稳定的；而具有弱吸引相互作用的费米气体在一定条件下可出现不稳定性.给出了不稳定性的粒子数密度判据和温度判据，就不同逸度情况下临界粒子数密度的具体表达结果以及温度、粒子质量和吸引相互作用对临界粒子数密度的影响进行了讨论. 关键词： 费米气体 相互作用 不稳定性判据     

Status and recent developments in NN → NNπ

We present a summary of the recent developments in pion production in NN collisions within chiral effective field theory.     

ωNN强相互作用的核物质系统在高温下的介电性质

从QHD-1场方程出发,用动力论的方法计算得到ωNN强相互作用的核物质系统的介电函数,并具体分析了在高温下介电函数的特征及其物理背景.     

Models of πNN interactions

A NN model inspired by Quantum Chromodynamics is presented. The model gives an accurate fit to the most recent Arndt NN phase shifts up to 1 GeV and can be applied to study intermediate- and high-energy nuclear reactions.Invited talk to the symposium Mesons and Light Nuclei IV, Bechyn, Czechoslovakia, September 5–10, 1988.This work is supported by the U.S. Department of Energy, Nuclear Physics Division, under contract W-31-109-ENG-38.     

New nuclear three-body clusters φNN

Binding energies of three-body systems of the type φ + 2N are estimated. Due to the strong attraction between φ-meson and nucleon, suggested in different approaches, bound states can appear in systems like φ + np (singlet and triplet), φ + nn and φ + pp. This indicates the principal possibility of the formation of new nuclear clusters.     

将硬盘阵列技术应用于数字化理科数据库构建

目前学校的服务器基本都使用了磁盘阵列技术,在数据存储的空间大小、稳定性、安全性上就具有了保障。随着自媒体时代的到来,个人终端的存储数据量也呈现级数上升。本文就简单的讲述了将服务器上使用的磁盘阵列技术应用到个人终端存储中来,从而为数字化理科数据库的构建增容添翼、保驾护航。     

A search for πNN bound systems

The d(π⁺, π⁻)T⁺⁺⁺ and the d(π⁻, π⁺) T⁻ reactions were studied at an incident pion energy of 260 MeV. Outgoing negative pions were detected at 35° and 55° in the first reaction, and the positive pions at 45° in the second. Indications for structures corresponding to a (π⁺pp) system with a mass of 2003.0±1.0 MeV and a (π⁻nn) system with a mass of 200.1±1.5 MeV were observed with marginal statistical significance. Upper limits for the cross sections are obtained.     

ωNN vertex function and the γπππ anomaly

We show that the empirical ωNN form factor (cut-off 1400–C1500 MeV) can be understood as arising from a combination of a quark model form factor (typical cut-off 700–C800 MeV) and an anomalous form factor ～ q ² arising from the 3π-intermediate state. The anomaly contributes to the Dirac form factor F ₁(q ²) with F ₁(0) = 0, (and sizable), and to the Pauli form factor F ₂(q ²) with F ₂(0) ≠ 0. The resulting tensor coupling F2(0) is sensitive to the cut-off of the pion momenta in the two-loop integrals and turns out to be small for values around 1 GeV. The quark model ωNN tensor coupling F ²(0) vanishes for point-like quarks. The anomaly, however, contributes a non-vanishing tensor coupling which can be seen to effectively enhance the vector coupling in NN models which do not include a tensor coupling.     

REPULSIVE CORE STRENGTH OF THE NUCLEON-NUCLEON INTERACTION

The contributions to the repulsive corestrength of the N-N force from both the quarkpion and quark-gluon interactions in the Chiral(or Cloudy) Bag Model are calculated. These contributions are about several hundred MeV,a great part of which comes from the quark-pion interactions. It is found that when self-energies due to both gluon and pion exchange are considered,the contribution from the self-energy due to pion exchang is more important than that from the direct and exchange energy of guarkpion interactions.     

INTERACTION BETWEEN A LIQUID LAYER AND VIBRATING PLATES: APPLICATION TO THE DISPLACEMENT OF LIQUID DROPLETS

Various experiments have been performed to study the interaction of a liquid layer and vibrating plates. A liquid layer deposited on a vibrating plate exhibits a deformation of the surface with a high amplitude of vibration (larger than 1 μm at 30kHz). Furthermore, a water droplet placed on the vibrating plate moves towards an antinode of vibration. These non-linear phenomena are explained by the action of acoustic radiation pressure. An application to the displacement of droplets is presented.     

冲击加载下材料破坏准则的规范场理论

 本文给出了规范场理论中的Bessel-Hagen散度不变性的广义E. Noether对称定理。应用此定理及缺陷的规范场理论，研究了材料在强动外载作用下的动力学性质，给出了破坏准则的一般公式，此公式定量地反映了缺陷和外载对材料破坏的影响。作为一个例子，研究了强冲击波作用下材料的破坏情况，使一般公式具体化了，而且定量地反映了冲击波的速度、压力和缺陷对材料破坏的影响。     

光声光谱在纤维样品分析中的应用

本文通过不同状态纤维样品的红外光声光谱的比较以及同一样品的红外光声光谱与红外光谱的比较表明：红外光声光谱用于纤维样品的分析，与红外光谱相比具有简单快速，分辨率好，信噪比高等优点，是研究纤维样品很好的分析手段。     

超几何方程的解在函数展开中的应用

本文应用超几何方程在正则奇点邻域的解得到各种与超几何函数石关的函数在该邻域的展开式。对第一、二类完全椭圆积分不仅给出展开形式,而且列举了数值计算结果。     

光纤传感器在旋筒法实验中的应用

利用改进的旋筒和光纤传感器精确测量了液体粘滞系数，使旋筒法实验产生了由定性到定量的转变。     

研究激子-声子相互作用问题的积分算符方法

本文以激子与极性声子的相互作用问题为例,提出采用积分算符方法来讨论激子-声子相互作用的动力学问题。这种方法与以前许多作者讨论该问题时采用的方法不同。本方法的特点是:除了能得到与实验测定值符合得较好的结合能数据外,还可以同时得到激子寿命,质心质量重整因子,以及这些量随温度的变化关系。该方法既适用于讨论1s态激子,也适用于高于1s的态;并且该方法还可较方便地推广到各向异性和简并价带情形。 关键词：     

泡克耳斯效应在电学测量上的应用

对于电场测量,传统上采用的电学方法,会扰乱原有的电场分布,带来若干测量上的问题,应用泡克耳斯效应来测量电场,具有很强的抗电磁干扰性、测量灵敏度高、测量频带宽等电学方法难于相比的优点,文章叙述了泡克耳斯效应在电学测量上的应用,阐述了其测量电场的原理和测量系统,并探讨了为测量所需的电场分量,应如何选择泡克耳斯晶体和电场测定方向。     

LED在物理演示实验中的应用

本文利用发光二极管对电磁感应现象、自感现象等演示实验进行了改进,并用多个发光二极管组成的阵列形式来模拟直流电流流动方向和对电容的充电、电容的放电现象的演示,加强学生对直流电流的方向性的认识,便于学生观察电容的充电、电容放电的整个过程,明显提高了实验的效果。