Institutional Repository of Institute of Modern Physics, CAS
Not a member yet
5769 research outputs found
Sort by
Measurement of Production Cross Sections ofLight Scalar Mesons a0/f0(980) inProton-Deuteron Reactions withWASA-at-COSY
No full text高频变谐波同步加速的控制装置
No full text本实用新型涉及质子-重离子治癌同步加速器中加速离子的高频变谐波同步加速的控制装置。包括有PC机(1)，PC机(1)上的直接数字频率合成器(2)与分配器(4)相接，分配器(4)的输出口分别与第一相位检测电路(5)、控制放大器(6)和第二相位检测电路(14)相接，控制放大器(6)通过前置放大器(10)与高频发射机(11)相接，高频腔(12)与高频发射机(11)相连；数模转换器(3)分别与调制器(9)和第二相位检测电路(14)相接，调制器(9)分别与高频发射机(11)、高频腔(12)、第二相位检测电路(14)相接，其能够快速的变频，改变谐波次数，满足了实际使用中的需要，其结构简单，操作方便
Behavior of crystalline silicon under huge electronic excitations: A transient thermal spike description
No full textRecent experimental works devoted to the phenomena of mixing observed at metallic multilayers Ni/Si irradiated by swift heavy ions irradiations make it necessary to revisit the insensibility of crystalline Si under huge electronic excitations. Knowing that Ni is an insensitive material, such observed mixing would exist only if Si is a sensitive material. In order to extend the study of swift heavy ion effects to semiconductor materials, the experimental results obtained in bulk silicon have been analyzed within the framework of the inelastic thermal spike model. Provided the quenching of a boiling ( or vapor) phase is taken as the criterion of amorphization, the calculations with an electron-phonon coupling constant g(300 K) = 1.8 x 10(12) W/cm(3)/K and an electronic diffusivity D-e(300 K) = 80 cm(2)/s nicely reproduce the size of observed amorphous tracks as well as the electronic energy loss threshold value for their creation, assuming that they result from the quenching of the appearance of a boiling phase along the ion path. Using these parameters for Si in the case of a Ni/Si multilayer, the mixing observed experimentally can be well simulated by the inelastic thermal spike model extended to multilayers, assuming that this occurs in the molten phase created at the Ni interface by energy transfer from Si. (C) 2009 Elsevier B. V. All rights reserved
Combined study of gamma p ->eta p and pi(-)p ->eta n in a chiral constituent quark approach
No full textWithin a chiral constituent quark model approach, η-meson production on the proton via electromagnetic and
hadron probes is studied. With few parameters, the differential cross section and polarized beam asymmetry
for γp → ηp and differential cross section for π
−
p → ηn processes are calculated and successfully compared
with the data in the center-of-mass energy range from threshold up to 2 GeV. The five known resonances
S11(1535), S11(1650), P13(1720),D13(1520), and F15(1680) are found to be dominant in the reaction mechanisms
in both channels. Possible roles played by new resonances are also investigated; and in the photoproduction
channel, significant contribution from S11 and D15 resonances, with masses around 1715 and 2090 MeV,
respectively, are deduced. For the so-called missing resonances, no evidence is found within the investigated
reactions. The helicity amplitudes and decay widths of N
∗ → πN, ηN are also presented and found to be
consistent with the Particle Data Group values
A quick isolation method for mutants with high lipid yield in oleaginous yeast
No full textA novel method has been developed to easily isolate the mutants with high lipid yield after irradiating oleaginous yeast cells with carbon ions of energy of 80 MeV/u. Pre-selection of the mutants after ion irradiation was performed with culture medium in which the concentration of cerulenin, a potent inhibitor of fatty acid synthetase, was at 8.96 mu mol/l. Afterwards, lipid concentration in the fermentation broth of the pre-selected colonies was estimated by the sulfo-phospho-vanillin reaction instead of the conventional methanol-chloroform extraction. Two mutants with high lipid yield have been successfully selected out by the combined method. This easy and simple method is much less time-consuming but very efficient in the mutant isolation, and it has demonstrated great potential on mutation breeding in oleaginous microorganism
一种大功率开关电源A型芯体
No full text本实用新型公开一种大功率开关电源A型芯体。其结构特征是芯体是由整流桥的输出正极板、整流桥C相输入的板、整流桥B相输入的板、整流桥A相输入的板、电容正极板、电容负极板叠层安装，板间用垫柱支撑，然后与4个整流桥模块和2个IGBT模块套装在同一水冷板上。本实用新型减少了走线，克服导线电感和阻抗的影响，进而减小了电磁干扰，达到了抑制电磁干扰的目的
Radiosensitivity of hepatoma cell lines and human normal liver cell lines exposed in vitro to carbon ions and argon ions at the HIRFL
No full textHuman hepatoma (SMMC-7721) and normal liver (L02) cells were irradiated with c-rays, 12C6+ and
36Ar18+ ion beams at the Heavy Ion Research Facility in Lanzhou (HIRFL). By using the Calyculin-A induced
premature chromosome condensation technique, chromatid-type breaks and isochromatid-type breaks
were scored separately. Tumor cells irradiated with heavy ions produced a majority of isochromatid
break, while chromatid breaks were dominant when cells were exposed to c-rays. The relative biological
effectiveness (RBE) for irradiation-induced chromatid breaks were 3.6 for L02 and 3.5 for SMMC-7721 cell
lines at the LET peak of 96 keVlm 1 12C6+ ions, and 2.9 for both of the two cell lines of 512 keVlm 1
36Ar18+ ions. It suggested that the RBE of isochromatid-type breaks was pretty high when high-LET radiations
were induced. Thus we concluded that the high production of isochromatid-type breaks, induced
by the densely ionizing track structure, could be regarded as a signature of high-LET radiation exposure
Studies of a scintillator-bar detector for neutron wall at externaltarget facility
No full textTo achieve a better time resolution of a scintillator-bar detector for a neutron wall at the external target facility of HIRFL-CSR,we have carried out a detailed study of the photomultiplier,the wrapping material and the coupling media. The timing properties of a scintillator-bar detector have been studied in detail with cosmic rays using a high and low level signal coincidence. A time resolution of 80 ps has been achieved in the center of the scintillator-bar detector
The preparation of 238U targets on 2mm Al foils
No full textPreparation of 238U on 2μm Al foils by molecular plating technique is described. In order to obtain optimum conditions for deposition, several parameters influencing the quality of layers such as current density, distance between the anode and cathode and the deposition time were investigated. The target thickness was determined by spectrophotometry. The uniformity and morphology of the target surface were studied by means of scanning electron microscopy, energy dispersive X-ray spectrometry and Infrared spectra. The results show that uranium is deposited in its oxide or hydroxide form uniformly and adherently onto the foil
Design of general reconfigurable embedded micro-controller for synchrotron s monitor and control systems based on Nios-Ⅱ
No full textFPGA and dedicated micro-controller chips are widely used in HIRFL-CSR monitor and control systems.This paper discusses the characteristics of HIRFL-CSR s dedicated micro-controllers and it s requirement for micro-controllers. Using programmable technology and Nios-Ⅱ processor,we have designed and implemented a reconfigurable embedded micro(controller in altera cycloneⅡ2c35f484 FPGA. The micro-controller which has low hardware cost and 185 MHz maximum operating frequency can replace the dedicated micro-cont...中文文摘：讨论并参考了冷却储存环目前使用的专用微控制器的特点和其对微控制器的需求,采用可编程技术和Nios-Ⅱ处理器,在altera-cycloneII2c35f484芯片内实现可重构微控制器。该微控制器硬件资源消耗少,最大工作频率可达185MHz,可代替目前在监控系统中大量使用的专用微控制器芯片,减小硬件设计复杂度、节约成本