氧化镍位于510～610 nm的激光诱导荧光光谱 (cited: 1)

采用激光诱导荧光技术在510～650 nm研究了超声射流冷却下的氧化镍光谱,观测了55个振转谱带. 通过转动分析发现激发态的同位素位移、振转间隔和转动常数都表现出高度的不规则性,26个[Ω=0,1]-X³∑^-₀的跃迁谱带被暂时归属为5个振动序列. 此外实验中还观测了部分谱带的色散谱和寿命.     

一种改进的对力形式

通过引进一个关联因子提出了一种改进的对力形式,更合理地反映出短程关联的特点.解释了¹⁵⁷Tm的基态自旋为[411]1/2⁺这一实验事实.     

7Li和12C离子致DNA链断裂的研究

选用HI-13串列加速器产生的不同传能线密度的⁷Li和¹²C重离子,以不同的剂量对纯化的质粒DNA水溶液进行了辐照.利用原子力显微镜对这两种重离子诱发的DNA损伤进行了纳米水平的结构分析,并用ScionImage分析软件完成了DNA碎片长度的测量.得到了DNA分子超螺旋、开环和线性三种形态随剂量的变化情况以及DNA碎片长度的分布函数,并用Tsallis熵统计理论对实验结果进行了拟合.     

两体衰变径迹

在19MeV/u ⁴⁰Ar+²⁰⁹Bi反应中,云母片固体径迹探测器记录了几例连续两次衰变径迹.分析表明,这些事件两次衰变的时间间隔约为10^－13s.根据位垒穿透的WKB理论,这样的裂变是可能的.     

带三体势的IBM1的O(6)极限对偶偶Pt核的应用

通过在IBMI哈密顿中,引入一种简单的等效三体势,O(6)核能谱可得到不同程度的修正.本文具体计算了^192—198Pt偶偶同位素核的能谱和E2跃迁几率,理论计算值与实验数据符合较好.     

MSM结构GaAs探测器的抗辐照性能

研究一种双金属接触的GaAs半导体探测器在14MeV中子辐照下的性能.测量了探测器经过10¹²n/cm²中子辐照剂量后的反向漏电流、电荷收集效率和最小电离粒子能谱,并且与⁶⁰Co 1.25MeV光子辐照的测量结果相比较.对中子辐照引起探测器时间性能变化和辐照损伤机制进行了探讨.并根据实验结果提出了这种双金属接触GaAs探测器灵敏层分布的一种假设,理论计算和实验数据相符合.     

奇特原子核6,8He的电荷形状因子研究

应用相对论Eikonal近似计算了用不同模型给出的^6,8He的电荷半径和电荷分布的形状因子, 并将结果与⁶He和⁴He的实验结果进行了比较. 结果显示不同模型给出的电荷半径和电荷形状因子差别很大, 表明不同模型给出的晕中子与α核芯的关联有很大的差异. 计算和讨论结果为在下一代电子-原子核对撞机上可能进行的实验提供了理论参考, 同时, 也为现有讨论奇特原子核的理论模型提供了检验.     

铷原子蒸汽中的光偏振旋转效应

对铷原子(⁸⁷Rb)蒸汽中的法拉第旋转、光学偏振自旋转以及二者的叠加旋转效应进行了理论和实验研究.对三种情况下旋转现象建立了简单而有效的理论模型. 实验中把铷原子泡置于自行设计的磁屏蔽腔内, 以屏蔽地磁场的影响.实验选择⁸⁷Rb F=2→F'=3能级D2跃迁线并采用零多普勒光谱 实验结构消除多普勒展宽对实验光谱的影响. 实验中分别观测到了三种旋转现象,实验结果与理论模拟结果非常符合.     

重离子Bragg峰的研究及其应用

实验测定了由HIRFL引出的25、30MeV/u ⁴⁰Ar,离子经不同厚度降能片后的相对电离(Bragg曲线),并将实验结果同TRIM88程序的计算结果进行了比较,发现⁴⁰Ar离子贯穿深度较浅时,实验结果与程序计算符合很好. 并对中能重离子在水中贯穿深度与相对电离关系的计算,提出了一种对浅层且体积不大肿瘤的重离子治疗方案.     

133Sm和149Yb的β缓发质子衰变

利用⁴⁰Ca+⁹⁶Ru融合蒸发反应产生了近质子滴线核¹³³Sm, 配合氦喷嘴带传输系统采用“质子-γ”符合方法观测了它们的β缓发质子衰变, 其中包括半衰期、质子能谱、第二代子核低位态之间的γ跃迁, 并估计出衰变到第二代子核不同低位态的分支比. 通过统计理论拟合上述实验数据, 指认了¹³³Sm的自旋宇称的可能范围. 并用Woods-Saxon Strutinsky方法计算了限制组态的¹³³Sm的核势能面, 通过对比发现¹³³Sm的自旋宇称可能有两种成分:5/2⁺和1/2^－. 这一结果与2001年发表的¹³³Sm(EC+β⁺)衰变的简单衰变纲图是相容的. 此外用同一方法分析了2001年Eur. Phys.J.A12:1—4中发表的有关¹⁴⁹Yb的β缓发质子衰变实验数据, 由此指认了¹⁴⁹Yb的基态自旋宇称为1/2^－.     

打点计时器电源的改进

根据振荡电路产生不同周期的计时信号，对打点计时器的供电电源进行了改进。改进后，实验者可根据不同的运动速度来选择适宜的打点计时单位，使纸带上的点疏密程度较为合理，从而减少测量误差。     

Conditions for the weak energy dependency of effective interactions

We discuss the possibilities for the existence of effective interactions depending weakly on the energy in a given interval. These interactions may be used in computing matrixelements of the Greenoperator in a modelspace. To show that the interval in which the model is valid may principally be chosen at random, we introduce effective interactions with poles at the eigenvalues of the operatorH+λV ¹ and consider the necessary properties ofV ¹. The operatorV ¹ determines the modelspace, and there-fore the matrixelements of the Greenoperator which can be computed within the model.     

Neural mechanism for a cognitive timer

To examine a possible biological mechanism for a cognitive timer, the stochastic dynamics of a network of neurons possessing two stable states ("on" and "off" states) is studied. The fraction of on neurons existing at t = 0 remains large for an extended interval, and then abruptly falls. The distribution of the lengths of the interval is scale invariant in the following sense: The ratio (k root of (mu(k))/m, with m and mu(k) being the mean and the kth central moment, respectively, is invariant under scale transformations of m and mu(k). In the special case k = 2, this gives Weber's law, a hallmark of cognitive timing.     

Relaxation processes of water confined to AlMCM-41 molecular sieves. Influence of the hydroxyl groups of the pore surface

A series of AlMCM-41 molecular sieves was prepared with constant composition (Si/Al = 14.7) and presumably same pore structure but different pore diameters (from 2.3 to 4.6 nm). The pore size distribution is narrow for each sample. The rotational fluctuations of water molecules confined inside the pores were investigated applying broadband dielectric spectroscopy (10⁻²–10⁷ Hz) over a large temperature interval (213–333K). A relaxation process, slower than that expected for bulk water, was observed which is assigned to water molecules forming a surface layer on the pore walls. The estimated relaxation time has an unusual non-monotonic temperature dependence, which is rationalized and modeled assuming two competing processes: rotational fluctuations of constrained water molecules and defect formation (Ryabov model). This paper focuses on the defects and notably the influence of the hydroxyl groups of the pore walls. The Ryabov model is fitted to the data and characteristic parameters are obtained. Their dependence on pore diameter is considered for the first time. The found results are compared with those obtained for other types of molecular sieves and related materials.     

A New Model for The Formation of Mini Black Holes

A new model different from the Hawking model is suggested to describe the formation of mini (primordial) black holes. It is based on an idea that the fluids, which fill in the universe at the beginning just after the big bang, are separated into mini clusters, moving with supersonic velocities and colliding with each other under the forces of gravitational attractions. We show that between the time era from 10^–43 to 10^–8 sec. about 36 various generations of mini black holes with masses ranging in the interval 10^–5—10^–30 gm are possible.     

HL-2A 装置 2MW 低杂波反射保护技术研究

为提高 HL-2A 装置低杂波电流驱动系统的实验效率,研制了高反射保护系统。使用 Verilog 硬件描 述语言设计数字信号处理电路,选择 EPM240T100C4 型可编程逻辑器件(CPLD)实现数字信号处理;使用一个 14 位计数器,实现了在低杂波系统反射保护动作后间隔 3.6ms 后重启的功能。测试结果表明,该保护系统实现了设 计要求。     

On the maximum in hall coefficient temperature dependence in medium-doped n-GaAs

Hall coefficient and conductivity are measured in a wide temperature interval from 14.5 to 295 K in order to characterize n-type GaAs bulk monocrystals with moderate donor concentration 10¹⁷–10¹⁸ cm^–3. The weak temperature dependence of the Hall coefficient, showing a slight maximum at 120 K, is analyzed for the first time in terms of the model developed by Klotynsh and Bariss of discrete local levels degenerate with the continuum. For that purpose the presence of a discrete donor level degenerate with the conduction band is supposed and its energy position is calculated using the model. The concentration and the degeneracy factor of this level are determined by fitting the theoretical temperature dependence of the free electron concentration to the experimental one, the former being calculated using the charge neutrality equation. In addition, a qualitative interpretation of the Hall mobility temperature dependence is given.     

Comparison of measured and calculated high-resolution spectra of far-infra-red stratospheric emission

Summary Far-infra-red stratospheric emission spectra obtained from a balloon-borne platform at 38 km altitude with a spectral resolution of 0.0033 cm⁻¹ are compared with calculated spectra obtained with a radiative-transfer model. The overall agreement between the model and the measurements shows that a good understanding of this spectral interval has been obtained. Differences larger than the measurement error are observed in a few cases. The possible causes of these differences and the work that is needed in order to improve the data base of the model are discussed. Paper presented at the 1^o Congresso del Gruppo Nazionale per la Fisica dell'Atmosfera e dell'Oceano, June 19–22, 1984, Rome.     

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HT-7中性束诊断电源系统的计算机控制系统由PLC、工控机、逻辑控制和定时单元等组成。对起弧、束流引出等实验进行了研究。在多种参数下,通过调节弧压、进气量等观察了其对弧流的影响。初步实验结果表明,在高压35kV、弧流80A的情况下,束电流可以达到3.6A,引出的中性束流功率可以稳定地达到50kW以上。     

Energy dependence of optical-model parameters for the interaction of 6Li and 7Li Ions with 28Si nuclei at low energies

The results of a joint analysis of experimental data (angular distributions for scattering and total reaction cross sections) are presented for the case of the interaction of ^6,7Li ions with ²⁸Si nuclei at energies between 7.5 and 32 MeV. The respective calculations were performed on the basis of a deformed potential of the optical model by using the SPI-GENOA code. The energy dependences of the parameters of the macroscopic optical model and the total cross section for the (^6,7Li+²⁸Si) reactions were obtained over the energy interval from 7.5 to 32 MeV. The calculated angular distributions and total reaction cross sections are in good agreement with experimental data.