在几种约束模式下氘核对氘核的势垒贯穿

分别对游离态的氘氘核系统,磁阱位形下的氘等离子体,共有电子对约束的氘氘核系统,以及在晶格强力约束下实现了高密度积累的氘氘核系统中氘核间库仑相互作用的位能曲线进行了讨论,并以此为基础在一维方势垒近似下研究了在上述几种约束模式下氘核对氘核的势垒贯穿,以及因此而引起的核反应率随相关参数的变化情况.研究表明,冷聚变在物理上是说得通的,但聚变率太低,看不出有任何现实意义. 关键词： 势垒贯穿 核聚变 冷聚变     

冷聚变的全原子论

早在1989年我首先就以原子分子物理和晶体物理为基础,提出了一个冷聚变机理的初步理论.按照此理论,在晶体中两个氘核可以实现冷聚变,产生超热和聚变产物~4He.在此理论提出后,我们在实验研究中观测到以Pd或Ti为阴极电解重水过程中产生的明显的超热效应与聚变产物~4He.这表明我们提出的理论预言是正确的.但在过去长时间里,仍有很多学者对冷聚变产生的机理一直很不理解.为了对冷聚变机理有一个更清楚的解释,使其易于被理解和接受,我们在过去的20年中进行了反复深入的理论与实验研究.经过进一步深入分析,我们发现晶体中的冷聚变实际上是两个氘原子以全原子状态相互作用而产生的.因此提出了冷聚变的全原子论,并在本文中详细阐述.按照此理论进行分析,发现我们还可以用冷聚变的办法,得到~3He产物.这是很重要的发现,因为我们可以在地面上人造出核能原料~3He,就不一定要跑到月球上面去开采~3He了.     

凝聚态物质中冷核聚变可能性的理论探讨

本文对凝聚态物质中可能的冷核聚变现象,提出了强耦合冷等离子体模型。通过电化学分析,考虑到强Coulomb屏蔽效应和微热核效应,建立了冷聚变率表达式并导出其近似显式。理论结果表明,聚变率对氘核的低温度和高密度不很灵敏,而对局域氘核的屏蔽修正因子η是敏感的。当η>2时,冷聚变就可观测到。     

常温核聚变研究进展评述

早在1989年芶清泉教授就以原子分子物理和晶体物理为基础提出了冷聚变机理的理论.按照此理论,在晶体中可以实现冷聚变,产生超热和聚变产物4He.在此理论提出后,我们在实验研究中观测到了以Pd或Tin为阴极电解重水过程中产生的明显的超热效应与聚变产物4He.这表明我们提出的理论预言是正确的,在过去的18年中我们进一步进行了反复深入的理论和实验研究,所得结果将在本文中进行系统总结和讨论.     

低能氘团簇离子(d_3~ )诱发固体靶内D-D核聚变过程中的团簇效应研究

通过对由三个氘原子组成的氘团簇离子（ｄ＋３）与三个分立的氘核（３ｄ＋）在轰击吸氘固体靶时所发生的ＤＤ聚变反应率的差别的研究，进而揭示氘团簇离子在与固体靶中的氘核发生聚变反应时所体现出的团簇效应．实验结果显示，在１０—４０ｋｅＶ／ｄ能区，每个氘团簇中的氘核（ｄ＋３／３）所产生的聚变反应率高于具有相同速度的独立氘核（ｄ＋）所产生的聚变反应率．反之，在５０—１００ｋｅＶ／ｄ能区，独立氘核比之于氘团簇中的单个氘核所产生的聚变反应率要高．两者之间的比值具有非常明显的能量相关性．这种团簇特性与团簇离子本身特性及固体靶环境等多方面因素有关．对其作用过程和实验中观测到的现象的实质做了具体讨论．     

低能氘团簇离子(d+3)诱发固体靶内D-D核聚变过程中的团簇效应研究

通过对由三个氘原子组成的氘团簇离子(d⁺₃)与三个分立的氘核(3d⁺)在轰击吸氘固体靶时所发生的D-D聚变反应率的差别的研究，进而揭示氘团簇离子在与固体靶中的氘核发生聚变反应时所体现出的团簇效应.实验结果显示，在10—40keV/d能区，每个氘团簇中的氘核(d⁺₃/3)所产生的聚变反应率高于具有相同速度的独立氘核(d⁺)所产生的聚变反应率.反之，在50—100keV/d能区，独立氘核比之于氘团簇中的单个氘核所产生的聚变反应率要高.两者之间的比值具有非常明显的能量相关性.这种团簇特性与团簇离子本身特性及固体靶环境等多方面因素有关.对其作用过程和实验中观测到的现象的实质做了具体讨论. 关键词：     

核爆氘-氘聚变能电站——聚变能和平利用的一种可能的途径

简要地分析了利用核爆氘 氘聚变能发电的可行性及优点， 按10 kt TNT核爆氘 氘聚变的规模， 估算了热载体钠的储能作用及用量， 核爆冲击波对爆室壁的作用强度及爆室壁的承受能力。     

飞秒激光氘团簇库仑爆炸引发核聚变的机理研究

在超强飞秒激光与氘团簇的相互作用中，利用库仑爆炸模型，分析了可以引发核聚变的高能氘核产生的机理，提出了氘离子团簇膨胀尺寸与时间的关系式，计算了多种尺寸的氘团簇库仑爆炸时氘核的动能以及氘团簇的解体时间． 关键词： 飞秒强激光 氘团簇 库仑爆炸 核聚变     

核聚变中的核物理问题

采用标准的量子力学方位阱加库伦位垒,计算了氘-氘聚变截面。给出了0．2～280keY能区内的截面数据。与实验符合得很好。此模型说明了不可用Breit-Wigner公式来讨论轻核聚变反应。将此模型运用于束缚态带电粒子之间的核反应。可以解释一系列“异常现象”。并展现了开发不带强放射性的聚变能的前景。     

超强超短脉冲激光诱发大尺度氘团簇聚变

 利用低温脉冲气阀获得了平均含有3×103氘原子的氘团簇。在飞秒激光装置上实现了氘团簇聚变,每发中子产额为1×10³。中子产额对激光功率密度敏感,保持激光能量不变,随着激光焦斑的变大,DD聚变中子产额逐渐增加,最大值出现在激光焦斑为470 mm时;继续增大激光焦斑,没有观察到中子信号。实验结果还表明激光氘团簇聚变发生的区域主要是激光辐照的等离子体热区,此区域内邻近氘团簇库仑爆炸发射的高能氘离子碰撞引发聚变反应。     

Guided-Wave Two-Dimensional Acousto-Optic Scanner Using Proton-Exchanged Lithium Niobate Waveguide

Two-dimensional scanning of a 0.6328 mum guided-light beam has been realized using noncolinear acousto-optic (AO) coplanar Bragg diffraction together with colinear AO guided-mode to substrate radiation-mode conversion in a Z-cut Xpropagation LiNbO3 proton-exchanged (PE) waveguide. The two surface acoustic (SAW) waves utilized are at the center frequencies of 500 and 200 MHz, propagating in the Y and X axes, respectively. Two-dimensional scanning of approximately 720 resolvable light beam spots, namely, 18 40 (horizontal vertical) scanning, has been demonstrated using a light beam of 1.0 mm aperture. The total number of resolvable beam spots can be greatly increased from 720 by simply utilizing SAW transducers of larger bandwidth and a light beam of greater aperture. It should also be possible to significantly increase the diffraction efficiency from 3 % by optimizing the parameters of the PE waveguide and the SAWs.     

Femtosecond Transform-Limited Pulse Generation by Compensating for the Linear Chirp of SPM Spectra in Dispersion Shifted Fibers

A simple technique of pulse compression, based on the linear chirp compensation of self-phase modulation (SPM) spectra in dispersion shifted fibers, is demonstrated. The optimization procedure is carried out, for a short span of a single-mode fiber, using a parabolic law, which describes the behavior of the squared output pulse width versus the pump peak power in the case of Gaussian pulses. The experimental results give a minimum pulse duration of 233 fs, which is in good agreement with the model. Shorter and coherent pulses, down to 90 fs, have been obtained by inserting an interference filter at the optical output.     

Effect ofγ-radiation on the spectral luminescence characteristics of impure cadmium tungstate crystals

Results of a study of the effect of γ-radiation on the spectral luminescence properties of cadmium tungstate crystals doped with silver, bismuth, and molybdenum cations are presented. Spectral characteristics of the nondnnnoped crystals are briefly described. Absorption and photo and X-ray luminescence spectra of the crystals taken before and after exposure to γ-radiation (5.5·10⁴ Gy) are compared. It is found that the spectral characteristics of the crystals doped with silver, bismuth, and molybdenum cations do not change markedly after the exposure. The relation between the type of impurity-induced defects, individual characteristics of the impurity cations, and the character of the effect of γ-radiation on the spectral luminescence properties of impure crystals is analyzed (preliminarily). Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 1, pp. 55–60, January–February, 1997.     

Sorting of bending magnets for the SSRF booster

The Shanghai Synchrotron Radiation Facility(SSRF)booster ring,a full energy injector for the storage ring,is deigned to accelerate the electron beam energy from 150MeV to 3.5GeV that demands high extraction efficiency at the extraction energy with low beam loss rate when electrons are ramping.Closed orbit distortion(COD)caused by bending magnet field uniformity errors which affects the machine performance harmfully could be effectively reduced by bending magnet location sorting.Considering the affections of random errors in measurement,both ideal sorting and realistic sorting are studied based on measured bending magnet field uniformity errors and one reasonable combination of bending magnets which can reduce the horizontal COD by a factor of 5is given as the final installation sequence of the booster bending magnets in this paper.     

Theoretical analysis and simulation of conjugate heights for dual-conjugate AO system in lidar

A multi-conjugate adaptive optics （MCAO） can offer a possibility of widening field of view （FOV） characterized by the isoplanatic angle, and the choose of conjugate height becomes a basic problem for MCAO, which influences the size of iosplanatic angle. Considering the application of lidar, the isoplanatic angle＇s expressions of two deformable mirrors （DMs） MCAO for uplink and downlink are deduced. The effects of conjugate heights for dual-conjugate AO are thoughtfully discussed, and the isoplanatic angles are further analyzed. The results show that the isopanatic angle varies with the conjugate height and reaches the maximum as the conjugate height is at the optimal altitude. Moreover, the optimal conjugate height changes with the propagation distance.     

Quick single-photon detector with many avalanche photo diodes working on the time division

Due to the limit of response speed of the present single-photon detector, the code rate is still too low to come into practical use for the present quantum key distribution (QKD) system.A new idea is put up to design a quick single-photon detector.This quick single-photon detector is composed of a multi-port optic-fiber splitter and many avalanche photo diodes (APDs).Au of the ports with APDs work on the time division and cooperate with a logic discriminating and deciding unit driven by the clock signal.The operation frequency lies on the number N of ports, and can reach N times of the conventional single-photon detector.The single-photon prompt detection can come true for high repetition-rate pulses.The applying of this detector will largely raise the code rate of the QKD, and boost the commercial use.     

Measurement of nonlinear coefficient of optical fiber based on small chirped soliton transmission

We measure the waveform and phase curves of short optical pulses before and after transmission over different lengths of fibers by use of the pulse analyzer with the frequency-resolved optical gating (FROG),and numerically simulate pulse evolution under the experimental conditions.The nonlinear coefficient of the fiber is given by comparing the experimental results with the numerical ones.Difference between the experiment and numerical simulation is analyzed.     

Resonance scattering of canonical elastic shells in absorbing fluid medium

Resonance scattering of elastic spherical shell and cylindrical shell while the surrounding fluid medium has absorption is studied. The normal mode solution derived using exact elastic theory and the separation of variables is still applicable. However, the scattering form function has to be modified for the absorbing medium, otherwise the unreasonable result would be obtained. The backscattering form function in the absorbing medium is redefined, and the form function of elastic spherical and cylindrical shell with vacuum or solid matter filled is calculated in various absorption conditions. The results show that the absorption of surrounding fluid leads to notable attenuation of the coincidence resonances in the mid-frequency, but it has a little influence on the low-frequency resonance scattering induced by the filler inside the shell.