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Study on DNA Damage Induced by Neon Beam Irradiation in Saccharomyces Cerevisiae
No full textYeast strain Saccharornyces cerevisiae was irradiated with different doses of 85 MeV/u Ne-20(10+) to investigate DNA damage induced by heavy ion beam in eukaryotic microorganism. The survival rate, DNA double strand breaks (DSBs) and DNA polymorphic were tested after irradiation. The results showed that there were substantial differences in DNA between the control and irradiated samples. At the dose of 40 Cy, the yeast cell survival rate approached 50%, DNA double-strand breaks were barely detectable, and significant DNA polymorphism was observed. The alcohol dehydrogenase II gene was amplified and sequenced. It was observed that base changes in the mutant were mainly transversions of T-->G and T-->C. It can be concluded that heavy ion beam irradiation can lead to change in single gene and may be an effective way to induce mutation
PbWO_4晶体的光输出与能量分辨研究；Study on Light Output and Energy Resolution of PbWO_4 Crystal
No full text研究了多种包装材料和包装工艺对钨酸铅(PbWO4)晶体光输出和能量分辨的影响,测量结果与基于GEANT4的模拟结果符合很好,并由此确定了晶体的最佳包装方法
Longitudinal scaling property of the charge balance function in Au plus Au collisions at root s(NN)=200 GeV
No full textWe present measurements of the charge balance function, from the charged particles, for diverse pseudorapidity and transverse momentum ranges in Au + Au collisions at root S-NN = 200 GeV using the STAR detector at RHIC. We observe that the balance function is boost-invariant within the pseudorapidity coverage vertical bar-1.3, 1.3 vertical bar. The balance function properly scaled by the width of the observed pseudorapidity window does not depend on the position or size of the pseudorapidity window. This scaling property also holds for particles in different transverse momentum ranges. In addition, we find that the width of the balance function decreases monotonically with increasing transverse momentum for all centrality classes. (c) 2010 Elsevier B.V. All rights reserved
HIRFL-CSR电源数字控制系统硬件平台设计
No full text论述用于兰州重离子加速器冷却存储环(HIRFL-CSR)磁铁电源控制系统的数字控制系统硬件平台设计。该系统基于1mmBGA封装的ALTER corporation的cycloneⅢFPGA芯片,嵌入运行数字调节器软件算法,满足了针对具体被控对象参数要求的调节控制。用ARM(Advanced RISC Machines)作调节控制系统的核心处理器,完成系统的多线程任务处理;同时嵌入千兆光纤接口,实现外接DSP板处理数据的直接传输,提高了系统的实时性。该硬件平台实现了HIRFL-CSR电源系统的稳定、可靠和实时控制
Biosorption of uranium by chemically modified Rhodotorula glutinis
No full textThe present paper reports the biosorption of uranium onto chemically modified yeast cells, Rhodotorula glutinis, in order to study the role played by various functional groups in the cell wall. Esterification of the carboxyl groups and methylation of the amino groups present in the cells were carried out by methanol and formaldehyde treatment, respectively. The uranium sorption capacity increased 31% for the methanol-treated biomass and 11% for the formaldehyde-treated biomass at an initial uranium concentration of 140 mg/L The enhancement of uranium sorption capacity was investigated by Fourier transform infrared (FTIR) spectroscopy analysis, with amino and carboxyl groups were determined to be the important functional groups involved in uranium binding. The biosorption isotherms of uranium onto the raw and chemically modified biomass were also investigated with varying uranium concentrations. Langmuir and Freundlich models were well able to explain the sorption equilibrium data with satisfactory correlation coefficients higher than 0.9. (C) 2010 Elsevier Ltd. All rights reserved
80 MeV/u C-12离子诱变选育PHB高产菌株；A strain of high PHB output by mutagenesis of 80 MeV/u C-12 ions
No full text用80MeV/u12C6+离子对一株积累聚β-羟基丁酸酯(PHB)的芽孢杆菌(BacillusP-9)进行诱变选育,最终获得PHB高产株菌G15,其PHB产量达2.93g/L,与出发菌株相比较,PHB积累量提高了1.5倍。研究结果表明,本试验辐照最佳剂量为15Gy。重离子辐照诱变育种效果显著,具有广阔的发展应用前景
An untuned MA-loaded cavity for HIRFL-CSR
No full textIn order to realize high energy density physics and plasma physics research at HIRFL-CSR, a magnetic alloy (MA)-loaded cavity has been studied. According to the theoretical calculation and simulation for the MA-loaded cavity, we achieved a better result. The MA-loaded cavity had a higher mu Q f value, with a higher shunt impedance and a higher accelerating gradient. The accelerating gradient was about 95 kV/m at 1.8003 MHz, 130 kV/m at 0.9000 MHz. Compared with the ferrite-loaded cavities that are used at HIRFL-CSR, with about 10 kV/m accelerating gradient, the MA-loaded cavity obviously has an advantage. The results of the theoretical calculation and the simulation, which meet the design requirements are in good agreement
Commissioning of electron cooling in CSRe
No full textThe 400 MeV/u C-12(6+) ion beam was successfully cooled by the intensive electron beam near 1 A in CSRe. The momentum cooling time was estimated near 15 s. The cooling force was measured in the cases of different electron beam profiles, and the different angles between the ion beam and electron beam. The lifetime of the ion beam in CSRe was over 80 h. The dispersion in the cooling section was confirmed as positive close to zero. The beam sizes before cooling and after cooling were measured by the moving screen. The beam diameter after cooling was about 1 mm. The bunch length was measured with the help of the signals from the beam position monitor. The diffusion was studied in the absence of the electron beam
Investigation of the energy resolution with a RETGEM detector
No full textA novel Micro-pattern gaseous detector (MPGD), thick GEM with electrodes made of a resistive material (RETGEM) is presented. In this paper we mainly investigate the energy resolution of a RETGEM in Ar+CO2 with different gas mixtures. The results indicate that an energy resolution 30% in single and double mode can be obtained. The existence of an optimum energy resolution is discussed
Controlled crystallinity and crystallographic orientation of Cu nanowires fabricated in ion-track templates
No full textThe hallmark of materials science is the ability to tailor the structures of a given material to provide a desired response. In this work, the structures involving crystallinity and crystallographic orientation of Cu nanowires electrochemically fabricated in ion-track templates have been investigated as a function of fabrication condition. Both single crystalline and polycrystalline nanowires were obtained by adjusting applied voltages and temperatures of electrochemical deposition. The anti-Hall-Petch effect was experimentally evidenced in the polycrystalline nanowires. The dominant crystallographic orientations of wires along [111], [100], or [110] directions were obtained by selecting electrochemical deposition conditions, i.e., H2SO4 concentration in electrolyte, applied voltage, and electrodeposition temperature