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Production of new superheavy Z=108-114 nuclei with U-238, Pu-244, and Cm-248,Cm-250 targets
No full textWithin the framework of the dinuclear system (DNS) model, production cross sections of new superheavy nuclei with charged numbers Z=108-114 are analyzed systematically. Possible combinations based on the actinide nuclides U-238, Pu-244, and Cm-248,Cm-250 with the optimal excitation energies and evaporation channels are pointed out to synthesize new isotopes that lie between the nuclides produced in the cold fusion reactions and the Ca-48-induced fusion reactions experimentally, which are feasible to be constructed experimentally. It is found that the production cross sections of superheavy nuclei decrease drastically with the charged numbers of compound nuclei. Larger mass asymmetries of the entrance channels enhance the cross sections in 2n-5n channels.National Natural Science Foundation of China 10805061
10775061
Special Foundation of the President Fund
Chinese Academy of Sciences
Major State Basic Research Development Program 2007CB81500
Analysis of the xuv photoabsorption spectrum of Au2+, Au3+, and Au4+
No full textThe photoabsorption processes of Au2+, Au3+, and Au4+ have been investigated experimentally and theoretically in the 70-127 eV region. Using the dual laser-produced plasma technique, the 4f and 5p photoabsorption spectrum has been recorded at 50 ns time delay and was found to be dominated by a great number of lines from 4f-5d, 6d and 5p-5d, 6s transitions, which have been identified by comparison with the aid of Hartree-Fock with configuration interaction calculations. The characteristic feature of the spectrum is that satellite lines from excited configurations containing one or two 6s electrons are more important than resonance lines, and with increasing ionization, satellite contributions from states with one 6s spectator electron gradually become more important than those with two 6s spectator electrons. Based on the assumption of a normalized Boltzmann distribution among the excited states and a steady-state collisional-radiative model, we succeeded in reproducing a spectrum which is in good agreement with experiment.National Natural Science Foundation of China 10774122
10876028
China/Ireland Science and Technology Collaboration Research Fund CI-2004-07
Specialized Research Fund for the Doctoral Program of Higher Education of China 20070736001
Foundation of Northwest Normal University NWNUKJCXGC03-2
Development and transition of spiral wave in the coupled Hindmarsh-Rose neurons in two-dimensional space
No full textThe dynamics and the transition of spiral waves in the coupled Hindmarsh-Rose (H-R) neurons in two-dimensional space are investigated in the paper. It is found that the spiral wave can be induced and developed in the coupled HR neurons in two-dimensional space, with appropriate initial values and a parameter region given. However, the spiral wave could encounter instability when the intensity of the external current reaches a threshold value of 1.945. The transition of spiral wave is found to be affected by coupling intensity D and bifurcation parameter r. The spiral wave becomes sparse as the coupling intensity increases, while the spiral wave is eliminated and the whole neuronal system becomes homogeneous as the bifurcation parameter increases to a certain threshold value. Then the coupling action of the four sub-adjacent neurons, which is described by coupling coefficient D', is also considered, and it is found that the spiral wave begins to breakup due to the introduced coupling action from the sub-adjacent neurons (or sites) and together with the coupling action of the nearest-neighbour neurons, which is described by the coupling intensity D
HIRFL-CSR complex
No full textThe construction and commissioning of HIRFL-CSR were finished in 2007. From 2000 to 2005 the subsystem and key devices of CSR were successfully fabricated, such as magnet, power supply, UHV system, e-cooler, electric-static deflector with the septum of 0.1 mm, and the fast-pulse kicker with the rise time of 150 ns. After that the CSR commissioning activities were performed in 2006 and 2007, including the accumulation of those heavy ions of C, Ar, Kr and Xe by the combination of stripping injection (STI) or multiple multi-turn injection (MMI) and e-cooling with a hollow e-beam, wide energy-range synchrotron ramping by changing the RF harmonic-number at mid-energy, the beam stacking in the experimental ring CSRe, the RIBs mass-measurement with the isochronous-mode in CSRe by using the time-of-flight method, and the ion beam slow-extraction from CSRm.Supported by National Natural Science Foundation of China (10635090
EC/beta(+) decay of six medium-heavy nuclei
No full textPrevious experimental results of (EC+beta(+)) decay for the medium-heavy nuclei reported by our group since 1996, including Er-153, Yb-157, Fr-209, Ce-128, Ce-130, and Pr-128 have been briefly summarized. The observed low-lying states in their daughter nuclei have been reviewed in a systematic way and compared with different model calculations. Finally, some questions have been put forward for further study and discussion
Quark distributions in nuclei and nuclear effects on nucleon structure functions
No full textExtended quark distribution functions are presented obtained by fitting a large amount of experimental data of the l-A DIS process on the basis of an improved nuclear density model. The experimental data of l-A DIS processes with A >= 3 in the region 0.0010 <= x <= 0.9500 axe quite satisfactorily described by using the extended formulae. Our knowledge of the influence of nuclear matter on the quark distributions is deepened.Natural Science Foundation of China 100775061
10505016
10575119
CAS Knowledge Innovation Project KJCX-SYW-N02
Major State Basic Research Developing Program of China 2007CB815004
Natural Science Foundation of Hebei Province in China A2005000535
10314
Experimental Study of Spin-exchange Optical Pumping in High-density Polarized 3He Target
No full text本工作搭建3He极化靶系统，研究了关键工艺和靶工作参数，度大
于 5amgs，Rb 和 Rb－K混合介质两类交换介质的3He极化靶进行
究，测量了极化度、3He 极化靶的输运曲线和自旋驰豫曲线，通过拟合
到自旋交换率及其常数和自旋交换效率，并与其他人的实验结果以及
结果进行了比较，主要结论如下：
（1）利用核磁共振方法 NMR 和电子顺磁共振方法分别测得的 3H
度很好符合；
（2）Rb－K 混合介质的 3He 靶与 Rb 介质的 3He 靶相比，极化度
但极化度的波动范围较大，与 D值相关；NMR信号与激光功率关系的
Rb 并没有完全被极化，所以3He 靶的极化度还有提高的空间…
SULFUR IX TO XIII SPECTRAL MEASURMENTS BETWEEN 170 AND 500Å
No full textThis paper reports laboratory measurements of the spectrum of highly ionized sulfur. The spectrum of S Ⅸ–S ⅩⅢ has been observed in the wavelength range 170–500 Å. A total of 54 lines have been measured. Forty-two of them have been classified as 2s22pk–2s2pk+1and 2s2pk–2pk+1 transitions. Twelve other lines have been ascribed to 2s–2p,4p–5s,5p–6s,5d–6p, and 6p–8d transitions. These spectral lines have been identified, among which 22 are new and accurately measured. The analysis of the spectra was based on a comparison with other experimental results and calculated values
高电荷态离子Arq+与Nb作用产生的X射线谱
No full text利用光谱技术在超导离子源SECRAL上研究了10~20keV·q的Arq+(q=16,17)离子入射在金属Nb表面产生的X射线谱.实验结果表明,高电荷态Ar16+离子在金属表面中性化过程中存在着多电子激发,Ar16+的K壳层电子被激发产生空穴,级联退激发射Ar的Kα特征X射线.Ar空心原子的K层发射X射线的强度随入射离子的动能减弱,靶原子Nb的L层发射X射线强度随入射离子动能的增加而增强.Ar17+单离子的Kα-X射线产额比Ar16+单离子的Kα-X射线产额大3个数量级
Radioadaptive Response of Low-Dose Heavy ions on Mice and Radiation Protective Effect of Melatonin
No full text研究目的： 1.研究碳离子辐射对小鼠不同组织抗氧化酶活性及细胞周期进程的影响。 2.研究低剂量碳离子预辐射对离体培养的黑色素瘤B16细胞及正常小鼠诱导的适应性反应。 3. 研究褪黑素（MLT）对碳离子的辐射损伤防护效应。 4. 研究碳离子层叠法辐照对H22荷瘤小鼠的治疗效果。研究方法： 1.采用不同剂量的碳离子辐照小鼠，用黄嘌呤氧化酶法检测外周血、肝脏及脑组织中抗氧化酶活性变化，流式细胞仪检测细胞周期阻滞情况。 2.采用低剂量碳离子预辐射离体培养的黑色素瘤B16细胞及正常小鼠，间隔4h后再以攻击剂量辐照，常规组织切片染色观察各组织器官病理变化，流式细胞仪检测细胞周期阻滞情况，黄嘌呤氧化酶法检测小鼠胸腺、脾脏及B16细胞中抗氧化酶活性，Western-blot法检测胸腺细胞及B16细胞中P53及P21蛋白表达情况，RT-PCR法检测CHK2及CDC25mRNA的表达水平。 3.在碳离子辐照小鼠1h前腹腔注射褪黑素，单细胞电泳方法检测胸腺、脾脏细胞的DNA损伤情况，微核法表征外周血的染色体损伤，黄嘌呤氧化酶法测定胸腺、脾脏细胞的抗氧化酶活性。 4.以碳离子层叠法辐照H22荷瘤小鼠，统计不同剂量照射后的肿瘤体积变化、肿瘤抑制率、肿瘤生长延迟天数及治愈率。结果： 1、小鼠血清和肝脏组织在辐射剂量较低（≤0.75Gy）时SOD活性高于对照组，随着辐射剂量的增高，SOD活性趋于降低；MDA含量在辐射剂量较低（≤0.3Gy）时低于对照，随着辐射剂量的增高其含量趋于升高；脑组织GSH浓度在照射剂量较低（≤0.5Gy）时大于对照组，随着照射剂量的升高其浓度趋于降低；低剂量辐射小鼠引起胸腺G2期细胞比例增加，脾脏G1期细胞比例增加。 2、小鼠肝脏、脾脏、肺脏及脑组织在攻击剂量辐射后，出现明显的病理变化，低剂量预辐射处理后病理变化减轻；低剂量预辐射增加胸腺G2期细胞及脾脏G1期细胞比例；相对于单纯攻击剂量辐射组，低剂量预辐射组胸腺组织P53及P21蛋白表达升高；CHK2 mRNA水平升高，CDC25 mRNA水平降低；脾脏及胸腺组织中SOD活性降低程度减弱，MDA含量升高趋势减弱。B16细胞经低剂量预辐射处理后上述指标均未发生明显变化。 3、与辐照处理组相比，褪黑素处理后小鼠的脾脏胸腺细胞DNA损伤拖尾率及彗尾长度明显降低；SOD活性升高，MDA含量降低，外周血微核率降低。 4、在不同剂量的碳离子辐照处理后观察的12天内，各组肿瘤生长速度减慢，生长延迟，肿瘤抑制率随时间而增加。15Gy照射组肿瘤生长速度最慢，肿瘤抑制率最大，肿瘤生长延迟最为明显，而且肿瘤治愈率达到30%。结论： 1． 低剂量12C6+离子全身辐照小鼠应激激活机体抗氧化系统，随辐射剂量的增加，机体抗氧化能力明显降低，导致脂质过氧化发生；低剂量的碳离子辐射导致小鼠胸腺细胞G2期阻滞，脾脏细胞发生G1期阻滞。 2． 低剂量12C6+离子预辐射引发小鼠正常机体产生适应性反应，减轻随后的大剂量辐射造成的损伤；低剂量12C6+离子预辐射对小鼠黑色素瘤B16细胞未引发适应性反应。 3． 15mg/kg的MLT可以对小鼠的重离子辐射损伤产生明显的防护效果。 4． 12C6+离子适形治疗小鼠移植性肿瘤H22，荷瘤鼠的存活时间、肿瘤体积变化、肿瘤的控制率、治愈率等结果显示，15Gy为最佳治疗剂量研究目的： 1.研究碳离子辐射对小鼠不同组织抗氧化酶活性及细胞周期进程的影响。 2.研究低剂量碳离子预辐射对离体培养的黑色素瘤B16细胞及正常小鼠诱导的适应性反应。 3. 研究褪黑素（MLT）对碳离子的辐射损伤防护效应。 4. 研究碳离子层叠法辐照对H22荷瘤小鼠的治疗效果。研究方法： 1.采用不同剂量的碳离子辐照小鼠，用黄嘌呤氧化酶法检测外周血、肝脏及脑组织中抗氧化酶活性变化，流式细胞仪检测细胞周期阻滞情况。 2.采用低剂量碳离子预辐射离体培养的黑色素瘤B16细胞及正常小鼠，间隔4h后再以攻击剂量辐照，常规组织切片染色观察各组织器官病理变化，流式细胞仪检测细胞周期阻滞情况，黄嘌呤氧化酶法检测小鼠胸腺、脾脏及B16细胞中抗氧化酶活性，Western-blot法检测胸腺细胞及B16细胞中P53及P21蛋白表达情况，RT-PCR法检测CHK2及CDC25mRNA的表达水平。 3.在碳离子辐照小鼠1h前腹腔注射褪黑素，单细胞电泳方法检测胸腺、脾脏细胞的DNA损伤情况，微核法表征外周血的染色体损伤，黄嘌呤氧化酶法测定胸腺、脾脏细胞的抗氧化酶活性。 4.以碳离子层叠法辐照H22荷瘤小鼠，统计不同剂量照射后的肿瘤体积变化、肿瘤抑制率、肿瘤生长延迟天数及治愈率。结果： 1、小鼠血清和肝脏组织在辐射剂量较低（≤0.75Gy）时SOD活性高于对照组，随着辐射剂量的增高，SOD活性趋于降低；MDA含量在辐射剂量较低（≤0.3Gy）时低于对照，随着辐射剂量的增高其含量趋于升高；脑组织GSH浓度在照射剂量较低（≤0.5Gy）时大于对照组，随着照射剂量的升高其浓度趋于降低；低剂量辐射小鼠引起胸腺G2期细胞比例增加，脾脏G1期细胞比例增加。 2、小鼠肝脏、脾脏、肺脏及脑组织在攻击剂量辐射后，出现明显的病理变化，低剂量预辐射处理后病理变化减轻；低剂量预辐射增加胸腺G2期细胞及脾脏G1期细胞比例；相对于单纯攻击剂量辐射组，低剂量预辐射组胸腺组织P53及P21蛋白表达升高；CHK2 mRNA水平升高，CDC25 mRNA水平降低；脾脏及胸腺组织中SOD活性降低程度减弱，MDA含量升高趋势减弱。B16细胞经低剂量预辐射处理后上述指标均未发生明显变化。 3、与辐照处理组相比，褪黑素处理后小鼠的脾脏胸腺细胞DNA损伤拖尾率及彗尾长度明显降低；SOD活性升高，MDA含量降低，外周血微核率降低。 4、在不同剂量的碳离子辐照处理后观察的12天内，各组肿瘤生长速度减慢，生长延迟，肿瘤抑制率随时间而增加。15Gy照射组肿瘤生长速度最慢，肿瘤抑制率最大，肿瘤生长延迟最为明显，而且肿瘤治愈率达到30%。结论： 1． 低剂量12C6+离子全身辐照小鼠应激激活机体抗氧化系统，随辐射剂量的增加，机体抗氧化能力明显降低，导致脂质过氧化发生；低剂量的碳离子辐射导致小鼠胸腺细胞G2期阻滞，脾脏细胞发生G1期阻滞。 2． 低剂量12C6+离子预辐射引发小鼠正常机体产生适应性反应，减轻随后的大剂量辐射造成的损伤；低剂量12C6+离子预辐射对小鼠黑色素瘤B16细胞未引发适应性反应。 3． 15mg/kg的MLT可以对小鼠的重离子辐射损伤产生明显的防护效果。 4． 12C6+离子适形治疗小鼠移植性肿瘤H22，荷瘤鼠的存活时间、肿瘤体积变化、肿瘤的控制率、治愈率等结果显示，15Gy为最佳治疗剂