非线性偶极-交换表面自旋波的包络孤立子解

介绍了非线性表面自旋波理论研究的新进展 ,并对前人的理论做了推广 ,针对具有非均匀交换各向异性的偶极 交换铁磁介质的非线性表面自旋波的性质和行为进行了较为系统的理论研究. The new progress in the theoretical investigation on nonlinear surface spin waves is reviewed, and the theory mentioned above is generalized. A relatively systematical investigation on the behaviors and properties of the nonlinear surface spin waves in dipole-exchange ferromagnetic media with inhomogeneous exchange anisotropy is developed.     

A new tuning procedure for the DTL RF field pattern

The DTL tank is a multi-cell cavity. In a fabricated tank,the measured average axial field E₀ for each cell may obviously deviate from the designed value. It is generally thought the deviation is due to the errors in fabrication and assembly. But it is not always true. In this paper, it is shown that the deviation may already exist before fabrication in some cases. It is partly due to the imperfection of the current design procedures. A new design method is introduced to reduce the deviation in the design stage.     

Kinematics in Randers-Finsler geometry and secular increase of the astronomical unit

Kinematics in Finsler space is investigated. It is shown that the result based on the kinematics with a special Finsler structure is in good agreement with the reported value of the secular trend in the astronomical unit, dAU/dt=15±4[m/century]. The space deformation parameter λ in this special structure is very small, with a scale of 10^-6, and should be a constant. This is consistent with the reported value of an anomalous secular eccentricity variation of the Moon's orbit.     

Exact solution to two-dimensional isotropic charged harmonic oscillator in uniform magnetic field in non-commutative phase space

In this paper, the isotropic charged harmonic oscillator in uniform magnetic field is researched in the non-commutative phase space; the corresponding exact energy is obtained, and the analytic eigenfunction is presented in terms of the confluent hypergeometric function. It is shown that in the non-commutative space,the isotropic charged harmonic oscillator in uniform magnetic field has the similar behaviors to the Landau problem.     

HYBRID ORBITALS OF CARBON ATOMS IN THE D6hC36 MOLECULE UNDER THE ROTATING ELLIPSOID MODEL

The hybrid orbitals of carbon atoms in the D_6h C₃₆ molecule are studied using two rotating ellipsoid models. The model 1 is 1.66R for the short semi-axis and 2.34R for the long semi-axis, and the model 2 is 1.78R and 2.26R respectively, where R is the C-C bond length. By comparison,we think the model 2 to be more proper in revealing the electronic properties of the D_6h C₃₆ molecule. The component of s orbitals in the π states hybridized for each of the atoms is much larger than C₆₀, in which the s-orbit component is 0.0380 and the p-orbit is 0.9620. The most component is 0.2098 and the least is 0.0482 for model 1; the most is 0.1764 and the least is 0.0656 for model 2.     

OASIS4.0—a new version of the program OASIS for phasing protein diffraction data

<正>The program OASIS4.0 has been released.Apart from the improved single-wavelength anomalous diffraction (SAD) phasing algorithm described in a separate paper,an important new feature in this version is the automation of the iterative phasing and model-building process in solving protein structures.A new graphical user's interface(GUI) is provided for controlling and real-time monitoring the dual-space iterative process.The GUI is discussed in detail in the present paper.     

CO2激光干涉检验轮胎面面形及双曲率半径

A torus is a kind of aspherical surface，different from quadratic rotary surface.It plays an important role in special optical systems.However，up to now there is no effective method to test its wavefront.In this paper，a method is proposed using CO₂ (10.6μm) IR interferometry to test a torus，whose curvature radii is different from submillimeter deducing to micrometer，the principle is also given.Then a example torus is tested in self-developed CO₂ laser spherical interferometer.Some interferograms are shown.According to these interferograms the wavefront error and the difference of two radii can be obtained and shown in this paper.     

Transport for System with Three-Value Poissonian Noise

The transport of the overdamped Brownian particles in a spatially periodic potential subject to the three-value Poissonian noise in the stationary state is considered. We show that for the spatially periodic potential, no matter whether it is asymmetric, or is symmetric, flux can be induced. But the mechanism is different. The former is the common action of broken reflection symmetry and transition among three-value Poissonian noise in a cyclic way; the latter is single behavior of transition among three-value Poissonian noise in a cyclic way.     

Design of a very high frame rate camera based on an asynchronous CCD driving method

A very high frame rate camera is designed based on an innovative CCD driving method. The CCD driving method is mainly implemented on frame transfer CCDs. Asynchronous drive timing sequences are applied in the image and storage section of the CCDs. Several rows of the charge in the image section are binned onto the same row in the storage section, and there are the same number of images to be stored in the storage section before they are read out. Based on the new driving method, the frame transfer CCDs can work at a very high frame rate in acquiring burst images though the reading speed remains at a lower level. A very high frame rate camera is designed in this paper. The innovative CCD driving method is mainly of concern. An e2v's CCD60 is adopted in the camera system, whose full size resolution is 128 × 128, and the up most frame rate is 1000 Hz in the conventional CCD driving method. By using the presented method, the CCD60 based imager is capable of operating at up to 40000 frames per second (fps) at a recognizable resolution of 128 × 32. Comparing cameras using traditional binning and region of interest technologies, the frame rate is normally less than 5000 fps while the resolution is only 32 × 32 left.     

Simulation of the acoustic field emitted from medical linear transducer in a heterogeneous tissue

A numerical model is developed to simulate the acoustic field in heterogeneous tissue from a medical linear transducer.The coupled full-wave equation for nonlinear ultrasound is solved using a staggered-grid finite difference time domain method.The distribution of acoustic pressure and power in human abdominal wall with heterogeneities in sound speed,density,and nonlinear parameter are obtained.Compared with homogeneous medium,when sound speed in tissue is uniform and density unchanged,the acoustic energy decreases only1.8 dB in the focal region;when density in tissue is uniform and sound speed unchanged,the energy decreases 3.8 dB in the focal region,which is almost the same as heterogeneous tissue.Thus,the primary factor of the aberration of focused beam is the heterogeneous distribution of the tissue sound speed.     

Ion Beam Driven Ion Cyclotron Double Layers

We present here a self consistent theory of small amplitude double layers associated with electrostatic ion cyclotron waves in a plasma containing hot electrons, cold ions and traversed by an ion beam. It has been shown that compressive type of double layers solution exists when θ_b (beam temperature) < α_b (beam concentration) < 1.     

用于聚焦离子束系统的离子源

介绍了现阶段两种用于聚焦离子束系统的离子源——液态金属离子源和气体场发射离子源的基本原理, 并对比了它们的优缺点。由于目前这两种离子源都难以满足纳米加工领域不断提高的技术要求, 因此提出了一种用于聚焦离子束的新型离子源——电子束离子源, 并介绍了电子束离子源的基本原理, 给出了设计参数、 模拟结果（20 kV的Ar+离子束, 发射度约为5.8×10-5·mm·mrad, 束斑约为1 μm）和初步的实验结果。 There are two kinds of ion sources, Liquid Metal Ion Source and Gas Field Ion Source, used to provide ion beams for the Focus Ion Beam system. The working mechanism of the two kinds of sources is presented and their advantages and disadvantages are summarized. With the rapid development in the nano technology, the requirements are hardly met with these two kinds of ion sources. Therefore, a new kind of ion source, electron beam ion source, is developed for the Focus Ion Beam system. The basic principle of the electron beam ion source is introduced and the design parameters, the result of the simulation (20 kV Ar+, extracted emittance is 5.8×10-5π·mm·mrad, raduis of the ion beam about 1 μm.) and the primary experimental results are presented     

兰州放射性束流线

兰州放射性束流线（RIBLL）是产生中能重离子放射性束流（RIB）的装置和高精度放射性束物理的实验谱仪．RIBLL的立体角接收度＞65msr、动量接收度达10％;RIBLL可提供极化RIB;RIBLL采用大接收度双消色差反对称结构,既可纯化放射性束,还可作为0°磁谱仪． Radioactive Ion Beam Line in Lanzhou (RIBLL) is a facility to produce intermediate energy radioactive ion beams (RIB), and also a high precision spectrometer for RIB physical experiments. The solid angle acceptance of RIBLL is 6. 5 msr. The momentum acceptance is about 10%. The polarized RIBs will be available. RIBLL is the equipment with double achromatic and asymmetric structure. So that it can not only sublimate the RIBs in pureness, but also operate as 0° magnet spectrometer.     

离子束治疗中的靶区运动补偿方法

相对于被动式束流配送系统,由患者呼吸因素而引起的肿瘤靶区运动会对主动式束流配送系统下的离子束放射治疗带来非常严重的影响,造成离子束辐射场剂量分布的严重畸变,甚至对肿瘤靶区周围的健康组织造成严重损伤,很大程度上影响离子束治疗的疗效。因此,在主动式束流配送系统下,建立针对由呼吸因素引起的运动肿瘤靶区的适形调强照射方法就显得必要,且具有重要意义。系统介绍了呼吸运动探测、4D-CT 以及目前主要的3 种运动补偿方法(多次扫描、呼吸门控和主动跟踪技术),并对这3 种方法在靶区适形度、稳健性以及技术复杂度等方面进行了比较。在靶区适形度方面主动跟踪技术优于门控技术,而门控技术又优于多次扫描技术;在稳健性方面多次扫描技术优于门控技术,而门控技术优于主动跟踪技术;在技术复杂度方面,多次扫描技术最简单,其次是门控技术,而主动跟踪技术最复杂。Active beam scanning results in serious distortion of ion-beam irradiation field in the presence of target motion and causes damage to healthy tissues round tumor target compared to passive beam shaping techniques. Therefore,it is necessary to establish suitable conformal irradiation methods for moving targets caused by the factor such as respiration in active ion beam scanning system. In this paper, motion detection, 4D-CT and three main ion beam specific mitigation techniques, namely rescanning, gating and beam tracking, are introduced. In addition, three motion mitigation techniques are compared comprehensively in terms of target conformation, robustness and mplementation complexity,respectively. For target conformation, the beam tracking is superior to gating, and gating is better than beam rescanning;the robustness decreases in the order rescanning-gating-beam tracking; for implementation complexity, beam rescanning is the most simple technology, followed by gating, while beam tracking is the most complex technique.     

Time Characteristics of the Ion Beam Cooler-Buncher at JYFL

A beam cooler for low-energy ion beams was constructed to improve the ion optical properties of radioactive ion beams produced at the IGISOL facility in Jyväskylä. The beam cooler is a buffer gas filled RF-quadrupole. The delay properties and the possibility to accumulate a continuous IGISOL beam and release it in short bunches is discussed.     

Computer Simulation of an Ion Beam Antenna

The feasibility of using a modulated beam of ions as an antenna in the magnetosphere is discussed briefly. A computer simulation of an ion beam in a plasma is presented in which the motion of the ions is prescribed while the electrons in the surrounding plasma are represented by concentric charged shells, each of which moves in the self-consistent field set up by the beam and the other shells. By following the motion of the shells on a computer, an attempt is made to estimate the sheath current that is induced in the plasma by the beam.     

Ion Beam Mixing for Silicide Formation

Refractory metal silcides are under intensive investigation to be used as contact and interconnect materials in VLSI circuits. Ion beam mixing has been proposed as a technique for simultaneous doping and metal silicide formution. This work presents a theoretical model for calculating the different parameters required for ion beam mixing through ion implantation. The minimum ion beam energy and dose for complete mixing is calculated. A plot of the obtained energy-dose relation shows that the dose increases linearly with energy. The dose-silicide thickness relation is also plotted. It is found that the thickness of the formed metal silicide increases linearly with the square root of the applied dose. A good agreement is found between the values and relations of the proposed model and experimental results.     

放射性核束物理与核天体物理

基于兰州重离子加速器国家实验室 (HIRFL )的中能放射性核束线 (RIBLL)及北京串列加速器国家实验室 (HI- 1 3 )的低能放射性核束线 (GIRAFFE) ,开展放射性核束物理和核天体物理研究 ,拟解决的关键科学问题是 :远离β稳定线核的结构与反应 ;超重新核素及近滴线核素的合成和性质研究 ,极端同位旋非对称核物质特性和关键的天体核反应研究 .研究内容分成 7个课题 :(1 )晕核研究 ;(2 )新核素合成及超重新核素研究 ;(3 )丰中子核结构和反应 ;(4)丰质子核结构和反应 ;(5 )高自旋的同位旋相关性 ;(6 )关键天体核反应 ;(7)系统的理论研究 .上述研究也将是2005年建成的国家大科学工程——兰州冷却贮存环的主要科学目标的研究基础 .简述了近期的主要工作进展. Based on the intermediate energy radioactive Ion Beam Line in Lanzhou (RIBLL) of Heavy Ion Research Facility in Lanzhou(HIRFL) and Low Energy Radioactive Ion Beam Line (GIRAFFE) of Beijing National Tandem Accelerator Lab (HI-13) the radioactive ion beam physics and nuclear astrophysics will be researched in detail. The key scientific problems which will be researched as high priority are: the nuclear structure and reaction for nucleus far from β-stability line; the syntheses...     

ECR离子源束流发射度的实验研究

利用最新自行研制的电扫描发射度探测系统, 在ECR离子源上进行了一系列关于ECR离子源引出束流发射度的研究. 这套电扫描发射度探测系统安装在中国科学院近代物理研究所(兰州)的LECR3试验平台的束运线上. 试验中, 通过测量相关参数, 研究了磁场、微波、掺气效应及负偏压效应等对引出束流发射度的影响. 利用实验所得的结果与关于ECR等离子体和离子源束流发射度的半经验理论, 分析推导了离子源各可调参数与ECR等离子体的直接关系, 这为分析探索ECR离子源的工作机制提供了一定的参考依据.