2014年 第31卷 第1期
在原子核熔合反应或裂变反应的动力学过程中，颈部变量都起着非常重要的作用。通常情况下，模型中变量的定义根据各种描述宏观形变的参数的不同而不同。为了进一步研究颈部增长在核熔合反应中的作用，通过引入弹核和靶核的形变参量来拓展哑铃模型。在此框架下，计算了从两个接触核到生成一个复合核过程的核熔合反应系统在不同形变下的势能曲面，同时又对核熔合反应体系的惯性张量和粘滞张量进行了计算，这些物理量的计算都为以后的朗之万动力学研究打下了基础。计算结果表明，在改进后的五参数哑铃模型之中，颈部变量是不稳定度并在核反应中起重要作用。The neck variable plays a key role in the dynamical processes of nuclear fusion or fission. Generally speaking, the definition for this variable is different for various parameterizations describing macroscopic nuclear shapes. In order to investigate the effects of increased neck in nuclear fusion, we extend the dumbbell parameterization by taking deformations of both the target and projectile into account. The potential energy surface (PES) with different shapes of nuclei is calculated, as well as the inertia mass and friction tensors. These calculations lay the foundation for Langevin dynamics. Analysis of the results shows that the neck variable in the proposed five-parameter dumbbell model is an unstable degree of freedom and play an important role in nuclear fusion.
在p+p 碰撞中，只有两个带头粒子，一个处在弹碎裂区，另一个处在靶碎裂区。研究表明:如同核-核碰撞一样，修正的Landau 流体力学模型本身不足以对p+p 碰撞中带电粒子赝快度分布的实验测量给出很好的描述，只有在考虑了带头粒子效应后，理论才能很好地与实验结果相一致。在ps=23.6~900 GeV 的整个能量范围内，理论与现有实验数据符合得很好。In a p+p collision, there are only two leading particles. One is in projectile fragmentation region,the other is in target fragmentation region. The investigation of present paper shows that, just like in nucleus-nucleus collisions, the revised Landau hydrodynamic model alone is not enough to have a good description to the measured pseudorapidity distributions of charged particles in p+p collisions. Only after the leading particles are taken into account as well, can the experimental data be matched up properly. The theoretical model works well in p+p collisions in the whole available energy region from ps=23.6 to 900 GeV.
基于微扰量子色动力学(pQCD)，计算了考虑核遮蔽效应和喷注淬火效应的pp 和PbPb 碰撞中大横动量K和π的光生过程的产额。在光生过程中可以看到K+/π+ 的增强。数值计算结果表明，所考虑的光生过程对K和 产生是一个很好的修正。By taking into account the effects of shadowing and jet quenching, the production of high-pT kaon and pion originating from photoproduction processes in pp and PbPb collisions is calculated based on perturbative quantum chromodynamics(pQCD). The enhancement of K+/π+ is found in photoproduction processes. The numerical results indicate that the photoproduction processes considering in our calculation are a good modification for kaon and pion production.
在非相对论的框架内和应用描述了高动量过程的巴黎势所产生的氘核的波函数，计算了氘核的电磁形状因子A(Q2)。A(Q2) 因子化为氘核的结构凾数Z(t) 和偶极形状GD(t) 之积。结构函数Z(t) 是用巴黎势的波函数做数值计算而得到的。对A(Q2) 的预言跟实验数据的分析非常一致，这一对实验结果的成功描述说明：氘核形状因子A(Q2) 这一简单的理论描述是非常成功的，并且可以用到氘核的其他静态性质的研究。Within non-relativistic framework and using deuteron wave function produced by the Paris potential which is designed just for describing nuclear process at high momentum transfers, we calculate deuteron electromagnetic form factor A(Q2) which is formulized as a product of the deuteron structure function Z(t) and dipole form factor GD(t). The structure function Z(t) is obtained numerically from the Paris potential wave function calculations. Our theoretical prediction for A(Q2) is in a good agreement with experimental data available. This successful t to data shows that the simple theoretical description of deuteron form factors A(Q2) works quite well, and could be applied to studying other static properties of deuteron.
鉴于量子场论中普遍存在的粒子产生和湮灭，把描述场量的独立变量个数从量子力学波函数的4 个常规时空坐标推广到了5 个，其中第5 个独立变量对应为粒子的内禀固有时，但是粒子运动的背景还是4 维的常规时空。在场函数中固有时之所以可以看作为独立于常规时空坐标的变量，不仅是量子物理所特有的概率性描述语言所允许的，而且有可能是描述量子场论中广泛存在的粒子产生和湮灭现象所必需的。与此对应，在量子场论中，引入了质量算符。由此，自由费米场在推广到五维概率分布空间和引入质量算符的基础上，根据相互作用的规范原理，引入了矢量规范相互作用和标量规范相互作用，同时所有的基本粒子的质量项都由质量算符自然地呈现。在此物理图像下，原则上基本粒子的质量应该通过求解相互作用耦合下的质量算符的本征值得到。此外，理论中存在普遍耦合的标量规范场和质量算符天然地联系在一起，有可能和引力作用对应起来。To investigate the mass generating problem without Higgs mechanism we present a model in which a new scalar gauge coupling is naturally introduced. Because of the existence of production and annihilation for particles in quantum eld theory, we extend the number of independent variables from conventional four space-time dimensions to ve ones in order to describe all degrees of freedom for eld functions while the conventional space-time is still retained to be the background. The potential fth variable is nothing but the proper time of particles. In response, a mass operator should be introduced. After that, the lagrangian for free fermion elds in terms of ve independent variables and mass operator is written down. By applying the gauge principle, three kinds of vector
gauge couplings and one kind of scalar gauge coupling are naturally introduced. In the current scenario,the mass spectrum for all fundamental particles is accounted for in principle by solving the eigenvalue of mass operator under the function of all kinds of interactions. Moreover, there no any auxiliary mechanism including spontaneous symmetry breaking get involved in the model. Therefore, traditional problems in the standard model such as the vacuum energy problem are removed from our model, as well as the hierarchy problem on the mass spectrum for fundamental particles.
研究设计了一种用于硼中子俘获治疗(BNCT) 的紧凑型固定磁场交变梯度(FFAG) 加速器。首先采用FFAG 加速器磁铁的线性简化模型，计算确定了加速器的基本结构参数；再用INAGILE 程序进行了磁聚焦结构的设计和优化，得到了Beta 函数、色散函数、包络函数及工作点等；采用MAD程序对设计结果进行了复算，并对两种程序的计算结果作了进一步的对比分析；最后采用ZGOUBI 程序进行非线性磁场下粒子追踪。FFAG加速器的超周期为6，能量为11 MeV，场指数k 为1.9，周长为11.179 5 m，结构紧凑。分析结果表明，优化设计的FFAG加速器达到了预期的设计目标。A compact FFAG accelerator for Boron Neutron Capture Therapy (BNCT) has been designed.Firstly, a linear simpli ed magnet model has been applied to calculate the basic parameters of FFAG accelerator; Then the WINAGILE program is used to design and optimize the lattice, as well as to obtain the critical parameters such as the Beta functions, the dispersion functions, the envelopes and the tunes; Also, the MAD program is used to check the design scheme; Finally, the ZGOUBI program is used to simulate the particles movement in the nonlinear magnetic eld. The super period of the FFAG accelerator is 6. The energy is 11 MeV and the eld index k is 1.9. The structure is compact with the circumference of 11.179 5 m. The results show that this optimized design has achieved the proposal object.
为满足C-ADS 项目建设对超导轮辐腔Spoke021 的需求，对Spoke021 进行了详细的电磁参数优化。对Spoke021 的参数化模型进行参数扫描，针对腔体的关键电磁特征量寻找可能存在的极值，详细分析、解释了优化过程中各个参数发生变化的物理意义。在Spoke021 各参数达到最终优化值时，表征腔体性能的两个关键比值分别为：Ep/Eacc = 3:14，Bp/Eacc = 4:77 mT/(MV/m)。考虑到次级电子倍增(Multipacting，MP)对Spoke021 运行中所能达到的性能指标有很重要影响，对腔体的MP进行了建模分析。结果表明，当Spoke021 工作在Eacc =10 MV/m情况下，没有发生MP，优化得到的参数可以满足Spoke021 工程设计的需要；最后计算了腔体的TTF曲线，表明该腔体具有较宽的速度接受度。The electromagnetic optimizations of a superconducting Spoke021 cavity is studied in detail for C-ADS project, in this paper. The cavity model has been parameterized, in order to find the possible maxima or minima of the key electro-magnetic parameters, the parameter sweep is performed. The cavity model has been parameterized. For finding the key electromagnetic feature, the geometric parameter sweep is performed. The physical interpretation for the variation of these electromagnetic parameters has been elaborated. The electromagnetic simulation gives the optimum parameters Ep/Eacc of 3.14 and Bp/Eacc of 4.77 mT/(MV/m).In addition, the Multipacting(MP) has a great effect on the electromagnetic properties of superconducting Spoke021 cavity. So the MP simulations have been done for this cavity, which shows that there is no MP phenomenon at 10 MV/m accelerator gradient. Therefore, the optimized cavity parameters can satisfy the requirements of the C-ADS project. Finally, the TTF(Transit Time Factor) curve of this cavity is calculated and it shows that this cavity has wide velocity acceptance.
中国科学院近代物理研究所在现有DG系列电子加速器技术的基础上，通过改进加速结构，研制了一台低能强流电子加速器，其设计指标为500 keV/150 mA。该加速器采用高压发生器倒置的结构，并增加了中磁圆盘，提高了电能转换效率。采用了较短的加速管结构，有利于强流电子束的传输，同时使加速器整体更为紧凑。加速器束流调试结果为500 kV/170 mA，完全优于设计指标。Based on the technology of the DG series electron accelerator, a 500 kV/150 mA electron accelerator was designed and manufactured at IMP(Institute of Modern Physics, Chinese Academy of Sciences). The new structure of high voltage and shorter accelerating tube have been used in this accelerator for high current. The specific features of this accelerator are compact of structure and higher power conversion efficiency. It has already passed the running test of 500 kV/170 mA, and the parameter is better than the designed value.
针对兰州重离子加速器冷却储存环(HIRFL-CSR) 复杂的现场环境和对现场故障精确检测报警的迫切需求，以TI 公司的MSP430 混合信号处理器为核心，采用负反馈电路稳定工作点，并结合RS-485现场总线技术完成了故障诊断报警电路的设计。结果表明：该诊断报警电路具有稳定性好、灵敏度高、耗电量小、价格低、使用方便、定位精确的优点，适合各种复杂的工作环境，可广泛应用于开关量诊断报警。现已成功应用于HIRFL-CSR 漏水检测报警系统中。In view of the complexity environment and the urgent need of eld fault diagnosis for Heavy Ion Research Facility in Lanzhou-Cooling Storage Ring(HIRFL-CSR), the detection alarm circuit for equipment fault is designed by using TI's MSP430 mixed signal processor, and using negative feedback to the stability of the circuit, and combining with RS-485 eld bus technology. The hardware system is introduced mainly in this paper, including the constitution and the working principle of the system, the function of the controller, the design of hardware and software. The circuit have the characteristics of fast response, high accuracy, good stability, high reliability, strong adaptability and ascendant quality-to-cost, etc. It can be widely used in the elds of switch quantity diagnosis and alarm system. It has been successfully used in the leakage detection alarm system of HIRFL-CSR.
在弹性散射实验中，探测器的位置校准是非常重要的。结合兰州放射性束流线(RIBLL) 的实际情况，以低能轻炮弹在重靶上的弹性散射截面在前角区为卢瑟福散射的事实为依据，发展了一种简单而有效的位置校准方法。通过蒙特卡洛模拟来检测弹性散射角分布与不同方向上位置未校准时的依赖关系。该方法成功地应用在7Be 与重靶的弹性散射实验中，得到了正确的微分截面角分布。In a typical nuclear elastic scattering experiment, differential cross section is very sensitive to the scattered angle and therefore the main source of systematic errors come from a millimetric uncertainties in the position measurement of detectors. A method for detector misalignment correction has been successfully applied to the elastic scattering of 7Be on Pb target at Elab=17.9 MeV/u at Radioactive Ion Beam Line in Lanzhou (RIBLL) at Heavy Ion Research Facility in Lanzhou (HIRFL). The correction method is based on the fact that the ratio of elastic scattering and Rutherford cross sections should be independent of scattering angle, and equal to unity for very forward angles. A Monte Carlo simulation was performed to examine the angular distribution of cross sections for a given shift of detector position.
采用外标转换谱指数(tSIE) 作为淬灭校正因子，通过研究闪烁液及样品总体积、闪烁液用量的影响获得液闪测氚时的最佳计数条件。结果表明，对于22 mL标准玻璃计数瓶，最佳计数体积为717 mL，体积过少或过多可导致高到10% 以上的测量误差，这主要是由液闪谱仪光电倍增管的面响应特性引起的。在获得的最佳计数体积基础上，对闪烁液的用量进行了研究。为了获得好的测量结果，闪烁液与样品的比例应高于2.4。另外，还通过实验研究了光照对测量结果的影响。在实验室条件下，实验室灯光及自然光所引起的本底辐射在样品静置2 h 后将不会对测量结果构成影响。The influence of sample volume and cocktail quantity on tritium measurement in liquid scintillation counter (LSC) was investigated experimentally in this paper to optimize the counting conditions. Results indicate that the optimal counting volume is between 7 mL and 17 mL using 22 mL glass vials, which should be mainly attributed to the sensitive character of photon multiplier tubes(PMTs) in LSC. With the obtained optimal volume, we also present the detailed procedure to determine the influence of cocktail quantity, which shows that the ratio of cocktail and sample water should be kept higher than 2.4 to obtain accurate results. In addition, experiments on the influence of light were also performed with pure cocktail and results indicate that 2 h is long enough to eliminate luminescence before counting.
硅微条探测器因具有很强的位置分辨率与能量分辨率而在世界各大核物理实验室得到广泛应用。中国科学院近代物理研究所研制了性能优越、位置精度达到0.5 mmx0.5 mm的双面硅微条探测器，用于HIRFL-CSR 的外靶实验终端谱仪(ETF) 上，用作径迹测量以及ΔE-E 望远镜系统ΔE 的探测。硅微条探测器体积小、集成度高，利用柔性印刷电路板(FPCB) 引出信号，配合ASIC 芯片的前端电路，能够方便地给出每一条的能量信息和位置信息。在此详细阐述了在HIRFL-CSR 的ETF 上双面硅微条探测器阵列的搭建，并测量了放射源在真空中探测单元的能量分辨本领。结果表明，该硅条探测器的每个探测单元对5~9 MeV能量的 粒子的能量分辨率在1% 左右。Silicon micro-strip detectors have been widely used in the world-famous nuclear physics laboratories due to their better position resolution and energy resolution. Double-sided silicon micro-strip detectors with a position resolution of 0.5 mm0.5 mm, have been fabricated in the IMP(Institute of Moder Physics,CAS) by using microelectronics technology. These detectors have been used in the ETF (External Target Facility) of HIRFL-CSR, as ΔE detectors of the ΔE-E telescope system and the track detectors. With the help of flexibility printed circuit board (FPCB) and the integrated ASIC chips, a compact multi-channel front-end electronic board has been designed to fulfill the acquisition of the energy and position information of the Silicon micro-strip detectors. It is described in this paper that the build-up of the Silicon micro-strip detector array in ETF of HIRFL-CSR, the determination of the energy resolution of the detector units, and the energy resolution of approximately 1% obtained for 5~9 MeV particles in vacuum.
基于硼转换的GEM(Gas Electron Multiplier) 探测器性能突出，计数率高达10 MHz以上，耐辐射，信号读出方式简单、灵活，位置与时间分辨率高，是下一代中子束流监测器极具优势的候选者。这种新型中子束流监测器主要由硼中子转换层、气体电离粒子放大的GEM以及二维读出电极组成。通过Geant4 程序包对探测器物理过程进行蒙特卡罗(Monte Carlo) 模拟，主要研究了硼中子转换层转换效率与厚度及中子波长的关系、出射粒子的能谱、不同气体比分不同气体厚度中的能量沉积、以及的能量沉积，计算比较了不同厚度GEM膜对快中子产生的影响。模拟结果表明，出射粒子在漂移区的能量沉积几乎与气体比分无关，硼层厚度取0.1 μm以下，漂移区厚度6 mm时，可以确保出射粒子在漂移区能量完全沉积，同时具有最佳n/γ 区分能力。The performance of a boron-coated GEM (Gas Electron Multiplier) neutron beam monitor is outstanding, with the counting rate up to 10 MHz, radiation resistance, flexible readout patterns, high resolution in position and time, which is considered as a good candidate for the next generation of neutron beam monitor. This new kind of neutron beam monitor mainly consists of boron convertor, GEM and two-dimensional readout electrode. In this paper, the Monte Carlo simulation on the physical process of the detector has been carried out by using Geant4 package, including the conversion efficiency of the boron layer influenced by the thickness and the neutron wavelength, the spectrum of emitted ions, and the energy deposition of the ions and the gamma in the different gas thickness of several gas volume ratio. Besides, the effect by the fast neutrons with GEM foils has also been calculated. The results show that the ions energy deposited in the drift region is almost independent of the gas volume ratio, the thickness 6 mm of the drift region is adequate for the full energy deposition and the boron thickness smaller than 0:1 m is the best choice for n/ separation. This work would be helpful for the detector design and provide an optimized option for the development of the boron-coated GEM neutron beam monitor.
运用密度泛函理论(DFT) 的B3LYP方法，优化了NpO，NpO2，NpO3 和Np2O3 分子的几何构型，分析了电子从Np 到O的转移情况。结果表明：NpO，NpO2，NpO3 和NNp2O3的自旋多重度分别为6，2，2 和9，对称性分别为Cv，Dh，Cv 和Dh 时相应分子处于稳定结构；对所有分子而言，分子能级在􀀀50 eV 左右的态主要由Np-6s 轨道形成，在􀀀20 eV 附近的态主要由Np-6p 和O-2s 轨道混合组成，而大于􀀀11 eV 的态主要由Np-5f 和O-2p 轨道混合组成。同时，根据相关计算给出了分子基态结构的振动频率和光谱数据，并对红外光谱最大峰值的振动模式进行了指认。The NpO, NpO2, NpO3 and Np2O3 molecules geometric configurations have been optimized by using the B3LYP method of density functional theory (DFT), and the information of the electron transfers from Np to O atoms has also been analyzed. The results show that NpO, NpO2, NpO3 and Np2O3 molecules stay in the stable structure when their spin multiplicities are 6, 2, 2 and 9, and symmetries are C∞v, D∞h, C2v and D3h, respectively; For all molecules, molecular orbitals were formed from Np-6s orbital when energy near 50 eV, formed from Np-6p mixture with O-2s orbitals when the energy near 20 eV, and formed from Np-5f mixture with O-2p orbitals when the energy greater than 11 eV. Meanwhile, the vibrational frequencies and spectral data of the ground state structure have been given. We also identified vibrational modes corresponding to the maximal peaks of infrared spectrum.
随着微电子器件集成度增加，由入射离子在器件灵敏区内引起的 电子分布对器件单粒子效应的影响越来越显著; 尤其是它极易引发多位翻转，严重影响设计加固的有效性。首先利用蒙特卡罗软件包Geant4 模拟得到重离子在器件灵敏区内产生的 电子分布，分析得出以下规律: 入射离子单核能越高，其产生δ电子分布的径向范围越大; 单核能相同的不同种离子，原子序数越大其产生的 电子密度越大。其次，通过模拟一款45 nm 静态随机存储器的单粒子翻转效应，说明 电子和灵敏区分布共同影响器件的多位翻转。当器件灵敏区间距一定时，多位翻转率随入射离子能量的升高先上升后下降；在多位翻转率峰值和布喇格峰之间，多位翻转率随入射离子线性能量传输(LET) 值的升高而降低，在该区域两侧多位翻转率随离子LET值的升高而升高。As the size of the transistor sensitive volume is decreased with the technology generation, the radial distribution of -electrons around the ion path has become more and more important to SEE(Single Event Effects) in semiconductor devices. Because it tends to, by causing MBU(Multiple-bit Upsets), invalidate error correcting codes which allow the device to work properly even when errors occur. In this work, Geant4 toolkit was used to simulate the radial ionization profile of heavy ions with different parameters. From the simulation,the certain rules were deduced: the higher the ion energy per nucleon, the wider the radial ionization track;for an identical energy per nucleon, the heavier the ion, the higher the electron density in track core. Then by simulating SEU(Single Event Upsets) of a 45 nm static random access memory (SRAM), effects of ion track structure on its MBU were illustrated. The maximum value of the MBU probability is determined not only by the structure of the device but also by the distribution of the -electrons generated by the incident ion. For ion energies between the top of the curve and the Bragg Peak, the MBU probability of the device decreases with the increasing LET values. For other ion energies, the probability increases as LET increasing.
对PAN/PEO 凝胶(5% PAN，5% PEO) 在1.0 MeV 电子束下进行了不同剂量的辐照。红外光谱测量表明，PAN/PEO凝胶辐照后发生了化学交联。分析结果指出，PAN/PEO的凝胶分数随着辐照剂量的增加而不断增加；其凝胶分数增长率的变化可以分为3 个阶段，即快速增加阶段(0 s 39kGy)、下降阶段(39s130 kGy) 和稳定阶段(>130 kGy)。拟合发现，引入材料刚性参数 的半经验修正方程与未考虑材料刚性的Charlesby-Pinner 方程相比，更符合实际测量值( 对于该配比PAN/PEO，为0.166)。交联度-辐照剂量曲线显示，交联度随辐照剂量的增加而增加，为设计新型能功能材料中所需的固定交联度的PAN/PEO凝胶提供了辐照剂量参考值。Polyacrylonitrile/polyethylene oxide (PAN/PEO, 5% PAN and 5% PEO) was irradiated by 1.0 MeV electron beam with different doses in this work. FTIR result indicated that PAN/PEO crosslinked after irradiation. It was pointed outby analysis that gel fraction of PAN/PEO increased with EB irradiation dose.The increasing rate of gel fraction could be divided into three stages, which were rapidly increasing stage (0 s 39 kGy), decreasing stage (39 s 130 kGy) and stable stage (more than 130 kGy). Theoretical calculation results showed that the values fitting by half-experience equation presented by Zhang Wanxi were closer to the measured values than Charlesby-Pinner equation fitting ones because of the introduction of rigidity parameter in the half-experience equation (for PAN/PEO, was 0.166). The curve of crosslinking degree vs irradiation dose showed that the crosslinking degree increased with the irradiation dose, and it could provide a referential irradiation dose when materials with fixed crosslinking degree were needed in new functional materials.
测量了入射能为1.9 ~11.3 keV/u 的O2+ 离子穿过碳膜诱导的前向、后向(分别对应出射表面和入射表面)电子发射产额。实验中，通过改变入射离子的能量和流强，系统地研究了电子能损和离子束流强度对前向、后向电子发射产额的影响。结果表明，在本实验的能量范围内，前向、后向电子发射产额与对应表面的电子能损有近似的正比关系，而与束流强度无关。分析还发现引起后向电子发射的动能阈值约为0.2 keV/u，势能电子发射产额约为1 e-/ion。We have measured the secondary electron emission yields in forward and backward directions from the carbon foils, which are penetrated by O2+ ion of the energy form 1.9 to 11.3 keV/u. In the experiment, the role of electronic energy loss and ion beam intensity in forward and backward electron emission yields have been systematically studied by changing the projectile ion energy and ion beam intensity. The results show that,forward and backward electron emission yields are approximately proportional to the electron energy loss at the exit surfaces and entrance surfaces respectively, and they are independent of the ion beam intensity. Further analyses show that, the kinetic energy threshold for the backward electron emission is about 0.2 keV/u, where the electron emission yield due to the potential energy deposition was roughly 1 e-/ion in the experiment.
荧光量子点由于具有发射荧光效率高、光稳定性好、无光漂白等优良特性，因此在生物学研究中得到广泛应用。用量子点标记细胞，通过量子点荧光可以对细胞进行长时程观察，实现活细胞动态示踪。利用量子点和DiO 荧光染料对A549 细胞膜双染，直观展示了量子点优于有机荧光染料的抗光漂白特性，并阐述了一种利用量子点对细胞A549 进行标记并观测在 粒子辐照下细胞损伤动态变化过程的方法，这种方法对于阐明粒子辐射作用细胞的过程、了解辐射损伤的机理有一定的优势。Owing to the excellent optical properties such as high quantum yield of emission, photo-stability and anti-photobleaching, uorescent quantum dots(QDs) now have been extensively applied in bioscience research. Labeling cells by quantum dots allow long-term observation of the cellular processes. In this paper, we employed both QDs and DiO dye to label cells and thus showed the superior anti-photobleaching property of QDs directly, and also reported the method of application of QDs in observing the damage process of A549 cells induced by particle irradiation, demonstrating the advantage of application of QDs in the radiobiology research.
探讨姜黄素(Curcumin，简称Cur) 对重离子辐射损伤小鼠睾丸组织的防护作用。小鼠灌胃不同剂量的Cur 后给予4 Gy 剂量12C6+离子束全身单次照射。24 h 后对小鼠睾丸组织形态学变化进行观察，并测定丙二醛(MDA) 含量、超氧化物歧化酶(SOD) 活性和过氧化氢酶(CAT) 活性。结果显示：中、高浓度Cur 预处理组对小鼠睾丸组织的形态具有较好的保护作用；低、中浓度Cur 预处理组MDA 含量显著降低(P < 0:05)；与单纯照射组相比，低浓度Cur 预处理组SOD 活性水平和中浓度Cur 预处理组CAT 活性水平显著提高(P < 0:05)。结果表明：Cur 对重离子全身辐射小鼠的抗氧化系统有一定的激活效应，对辐射损伤有一定的防护作用，其机制可能与Cur 清除自由基，保护脂质和蛋白质有关。The protective effect of Curcumin (Cur) against the irradiation damage of testis in mice induced by 12C6+ ion beams was studied. Male Kung-Ming mice were exposed to whole body uniformly irradiated with 12C6+ ion beams at 4 Gy after pretreated with Cur of different concentration. Then histological alterations were observed. Moreover, malonaldehyde (MDA) level, superoxide dismutase (SOD) activity and catalase (CAT) activity were also measured at 24 h after irradiation. The result showed that middle and high dose Cur pretreated have a good protective effect. Compared with irradiated group, MDA level decreased dramatically in the group of pretreatment with low and middle dose Cur (P < 0:05). On the contrary, SOD activity in the pretreated group with low dose Cur significantly increased (P <0:05). Similarly, CAT activity in the pretreated group with middle dose Cur significantly increased (P <0:05). Data suggested that Cur could activate antioxidant system of testis in mice induced by12C6+ ion beams, it have some protective effect to radiation damage. The mechanism may involve in its scavenging reactive oxidant species and thenprotecting lipid and protein capability.
采用100 MeV 的12C6+ 离子束和1.2 MeV 的电子束辐照薰衣草干种子，研究了2 个品种的薰衣草干种子对不同辐射源的辐照生物学效应，以期找到薰衣草干种子的最佳诱变参数。结果表明：不论是薰衣草701 还是702，经12C6+ 离子辐照后，其发芽率表现为先增大后减小的趋势；经电子束辐照后，发芽率随着剂量的升高而降低，电子束辐照后的发芽率要低于12C6+ 离子束。另外，2 个品种的薰衣草经12C6+ 离子辐照后，其胚轴胚根长度以及幼苗鲜重也较电子束辐照后的大。由此可知，重离子的辐照效果优于电子束的，有利于后期筛选出新的薰衣草突变株。To determine the optimal mutagenic parameters to Lavendula, the biological effects on the development of dry seeds of two Lavendula varieties (701 and 702) were comparatively studied between 100 MeV 12C6+ ion and 1.2MeV electron beam. The results showed that the germination percentage of 701 and 702 increased firstly and then decreased with the dose increased by using carbon ion irradiation. However, the germination percentage of 701 and 702 decreased with the increment of radiation dosage after being irradiated by electron beam. Furthermore, the results also showed that the germination percentage of Lavendula irradiated by electron beam was lower than that of carbon ion irradiation. In addition, the length of hypocotyl, embryonic root and fresh weight of seedlings of 701 and 702 irradiated by carbon ions were superior to those of electron beam irradiation. In brief, carbon ions are moresuitable for the mutation breeding of Lavendula compared to electron beams, which would contribute to obtain more novel mutants in the future.
嫦娥一号携带的 射线谱仪传回大量能谱数据，对其分析与解谱是一个比较复杂的过程。针对此问题，提出按照月表 射线来源的物理过程，分为月球表面天然放射元素、中子非弹性散射和中子俘获三部分。用MCNP 程序模拟其在GRS 中的能谱数据，将模拟结果叠加并与实测谱线对比，结果表明，模拟 谱线能帮助辨识出实测谱线中的部分关键元素，例如40K、214Bi 等。It is a more complex data processing problem of the data of -ray spectrum, which were collected by Chang'E-1 from lunar surface. It is presented that MCNP simulation for the spectra, according to three kinds of physical events, such as natural radioactive elements emission, the rays induced by inelastic neutron scattering and neutron capture on the lunar surface in this paper. The simulated results were superimposed and compared with the measured spectrum by Chang'E-1. The results show that 40K and 214Bi can be identi ed
from the measured data with our MCNP models.