同位旋非对称核物质性质与扩展的BHF方法(Ⅴ)三体核力对质子和中子单粒子势的影响

在扩展的同位旋相关的Brueckner Hartree Fock理论框架内 ,研究了三体核力对同位旋非对称核物质中质子与中子的单粒子势及其同位旋依赖性的影响 .

Study of the LED based light calibration system for neutron wall detector

The light calibration system is one of the key components of Neutron Wall detector. It is used to calibrate the electronics and to monitor the long-term stability of the detector modules. With the detaile investigations, a calibration system with high-power LED (3W) driven by the fast pulses has been carried out. It is also tested together with the detector module of the Neutron Wall and the result of the preliminary calibration demonstrates that it fulfills the needs. It's a new design proposal to the light calibration system of the fast scintillator detector.

基于RIBLL束线开展超重核合成的可行性研究

超重元素合成研究是当今国际上核物理研究的热点领域之一，也是中国科学院近代物理研究所的一个重要研究方向。根据实际情况，我们确定了两步走的发展方案。针对第一步发展方案，我们对RIBLL放射性束流线进行了改造。具体做法就是在RIBLL入口的前段增加一个速度选择器，并将原束流传输线的前半段改造为充气谱仪。本论文详细论述了RIBLL改造所涉及到的硬件设计和建造以及改造后系统的各项性能测试。硬件部分主要包括反应靶室、转靶系统、速度选择器、充气及气压控制系统、焦平面的衰变探测器等。性能测试方面主要开展了以下工作：(1) 利用放射源对速度选择器的接收立体角和动量接收度进行了测试；(2) 测量了铀离子经不同厚度碳膜后的电荷态分布，并与经验公式计算进行了比较；(3) 利用已知截面的反应道和靶反冲核分别对系统的传输效率、充气谱仪的最佳气压值和重离子在氦气中的平衡电荷态进行了研究。基于以上测试的结果，论文对在改造后的RIBLL上开展超重核合成研究的可行性进行了讨论。结论是由于RIBLL的二极磁铁的分析能力太强，大大降低了系统的传输效率，因此该谱仪只可用于原子序数Z≤107的超重核合成研究和生成截面较高的短寿命滴线核的合成及性质研究，对于更高原子序数的超重核合成研究应该放到正在建造的SHANS谱议上进行

Calorimetric study on two biphenyl liquid crystals

The molar heat capacities of the two biphenyl liquid crystals, 3BmFF and 3BmFFXF3, with a purity of 99.7 mol% have been precisely measured by a fully automated precision adiabatic calorimeter in the temperature range between T = 80 and 350 K. Nematic phase-liquid phase transitions were found between T = 297 K and 300 K with a peak temperature of T-peak = (298.071 +/- 0.089) K for 3BmFF, and between T = 316 and 319 K with a peak temperature of T-peak = (315.543 +/- 0.043) K for 3BmFFXF3. The molar enthalpy (Delta(trs)H(m)) and entropy (Delta(trs)S(m)) corresponding to these phase transitions have been determined by means of the analysis of the heat capacity curves, which are (15.261 +/- 0.023) U mol(-1) and (51.202 +/- 0.076) J K-1 mol(-1) for 3BmFF, (31.624 +/- 0.066) kJ mol(-1) and (100.249 +/- 0.212) J K-1 mol(-1) for 3BmFFXF3, respectively. The real melting points (TI) and the ideal melting points (TO) with no impurities of the two compounds have been obtained from the fractional melting method to be (298.056 +/- 0.018) K and (298.165 +/- 0.038) K for 3BmFF, (315.585 +/- 0.043) K and (315.661 +/- 0.044) K for 3BmFFXF3, respectively. In addition, the transitions of these two biphenyl liquid crystals from nematic phase to liquid phase have further been investigated by differential scanning calorimeter (DSC) technique; the repeatability and reliability for these phase transitions were verified. (C) 2004 Elsevier B.V. All rights reserved.

黄土丘陵沟壑区林地水文生态效应

根据安塞水土保持试验站1993～2002年林地径流小区的降雨产流产沙的定位观测资料及2002年土壤含水量资料,分析了不同树种对坡面尺度降雨产流产沙及土壤水分的影响。结果表明:场降雨径流小区的产流量、产沙量与降雨量具有较好的相关性;多元回归分析表明,场降雨产流量和产沙量与降雨量和最大30min雨强的乘积呈正相关,与植被覆盖度呈负相关,场降雨产沙量回归方程复相关系数为0.253,各处理场降雨产流量回归方程复相关系数的变化范围为0.465～0.723,均达到了极显著的水平(P<0.01)。同时,各树种均具有良好的减流减沙功能,与农地相比,年均产流量和产沙量分别减少4.8%～52.9%和26.8%～86.0%;沙棘纯林及其混交林的减流减沙效益优于油松纯林。同时,沙棘纯林及其各混交林在造林初期就表现出良好的减流减沙效益,随着树龄的增长,其作用更加明显;而油松纯林在造林初期作用不明显,甚至出现产流量和产沙量大于农地的现象,但随着树龄的增长,减流减沙作用逐渐呈现并增大。沙棘纯林及其混交林30cm以下土壤含水量在整个生长季中均呈递减趋势,生长季初(4月份)土壤含水量最高,而生长季末(10月份)降到最低值。2002年沙棘纯林的...

利用GIS和RS确定长白山自然保护区森林景观分布的环境范围

在对遥感数据进行景观分类和对环境因子进行空间表达基础上 ,在地理信息系统的支持下 ,确定长白山自然保护区森林景观分布的环境 (包括年均温、年降水量、坡度和坡向 )范围 .结果表明 ,从苔原、岳桦、云冷杉到阔叶红松林 ,最适海拔高度范围依次为 1780～ 2 2 12、170 5～ 195 6、10 4 2～ 16 2 5、82 3～ 1184m ;最适温度范围分别为 - 4 .75～ - 2 .4 0℃、- 3.4 2～ - 2 .0 7℃、- 1.4 9～ 1.39℃、0 .71～ 2 .37℃ ;最适降水范围分别为 10 34～ 1110、10 14～ 10 6 0、883～ 10 17、82 4～ 92 5mm ;长白山自然保护区的森林景观主要分布在平、缓坡地上 ,并与坡向关系密切 ,苔原在各个坡向上均有分布 ,且在各个坡向上分布面积的变化不大 ;岳桦、云冷杉林、阔叶红松林、山杨白桦林主要呈现北、西北向分布 ,其次为东北、西向分布 ;落叶松林主要为东北向分布 ,其次为东和北向分布 ;疏林主要为西向分布 ,其次为西南、西北和南向分布 ;风倒区主要为西、西南、西北向分布 .

Phase behavior of rare earth manganites

Among complex oxides containing rare earth and manganese BaLn(2)Mn(2)O(7)( Ln = rare earth) with the layered perovskite type and Ln(2)(Mn, M)O-7 with pyrochlore-related structure were studied since these compounds show many kinds of phases and unique phase transitions. In BaLn(2)Mn(2)O(7) there appear many phases, depending on the synthetic conditions for each rare earth. The tetragonal phase of so-called Ruddlesden-Popper type is the fundamental structure and many kinds of deformed modification of this structure are obtained. For BaEu2Mn2O7 at least five phases have been identified from the results of X-ray diffraction analysis with the space group P4(2)/mnm, Fmmm, Immm and A2/m in addition to the fundamental tetragonal I4/mmm phase. In the pyrochlore-related type compounds, Ln(2)Mn(2-x)M(x)O(7)(M = Ta, Nb, W etc), there also appear several phases With different crystal structures. With regard to every rare earth, Ln(2)MnTaO(7) phase is stable only for excess Ta and can be obtained under high oxygen partial pressure process. This group has trigonal structure with zirkelite type ( P3(1)21 space group).

烯烃共聚酯的合成与表征

通过环辛烯、环辛二烯和降冰片烯与ω-十一烯酸乙二醇二酯的易位共聚合及氢化反应合成了烯烃共聚酯 .改变聚合条件 ,可控制烯烃共聚酯的分子量、极性单体插入率和熔融温度等性质 .两段聚合过程适于制备高分子量的烯烃共聚酯 ,聚合物收率达 90 %,极性单体的插入率大于 1 0 %,熔融温度高达 120℃.

Patterning and optical properties rhodamine B-doped organic-inorganic silica films fabricated by sol-gel soft lithography

Rhodamine B (RB)-doped organic-inorganic silica films and their patterning were fabricated by a sol-gel process combined with a soft lithography. The resulted film samples were characterized by atomic force microscope (AFM), optical microscope and UV/Vis absorption and photoluminescence excitation and emission spectra. The effects of the concentration of the RB dye and heat treatment temperature on the optical properties of the hybrid silica films have been studied. Four kinds of patterning structures with film line widths of 5, 10, 20 and 50 mum have been obtained by micromolding in capillaries by a soft lithography technique. The RB-doped hybrid silica films present a red color, with an excitation and emission bands around 564 and 585 mum, respectively. With increasing the RB concentration, the emission intensity of the RB-doped hybrid silica films increases and the emission maximum presents a red shift. The emission intensity of the films decreases with increasing the heat treatment temperatures.

Construction and control of plasmid DNA network

The influences of different cations on plasmid DNA network structures on a mica substrate were investigated by atomic force microscopy (AFM). Interactions between the DNA strands and mica substrate, and between the DNA strands themselves were more strongly influenced by the complex cations (Fe(phen)(3)(2+), Ni(phen)(3)(2+), and Co(phen)(3)(3+)) than by the simple cations (Mg2+, Mn2+, Ni2+, Ca2+, Co3+). The mesh height of the plasmid DNA network was higher when the complex cations were added to DNA samples. The mesh size decreased with increasing DNA concentration and increased with decreasing DNA concentration in the same cation solution sample. Hence, plasmid DNA network height can be controlled by selecting different cations, and the mesh size can be controlled by adjusting plasmid DNA concentration.