MOVPE生长Al（0.35）Ga（0.65）As/GaAs量子阱结构的光致发光

于2010-11-23批量导入

16-channel 0.35 mu m CMOS/VCSEL optoelectronic devices

We report some investigations on vertical cavity surface emitting laser (VCSEL) arrays and VCSEL based optoelectronic smart photonic multiple chip modules (MCM), consisting of 1 x 16 vertical cavity surface emitting laser array and 16-channel lasers driver 0.35 mum CMOS circuit. The hybrid integrated multiple chip modules based on VCSEL operate at more than 2GHz in -3dB frequency bandwidth.

Summer monsoon intensity controls C-4/C-3 plant abundance during the last 35 ka in the Chinese Loess Plateau: Carbon isotope evidence from bulk organic matter and individual leaf waxes

IEECAS SKLLQG

Isospin diffusion and equilibration for Sn plus Sn collisions at E/A=35 MeV

Equilibration and equilibration rates have been measured by colliding Sn nuclei with different isospin asymmetries at beam energies of E/A = 35 MeV. Using the yields of mirror nuclei of Li-7 and Be-7, we have studied the diffusion of isospin asymmetry by combining data from asymmetric Sn-112 + Sn-124 and Sn-124 + Sn-112 collisions with those from symmetric Sn-112 + Sn-112 and Sn-124 + Sn-124 collisions. We use these measurements to probe isospin equilibration in central collisions where nucleon-nucleon collisions are strongly blocked by the Pauli exclusion principle. The results are consistent with transport theoretical calculations that predict a degree of transparency in these collisions, but inconsistent with the emission of intermediate mass fragments by a single chemically equilibrated source. Comparisons with quantum molecular dynamics calculations are consistent with results obtained at higher incident energies that provide constraints on the density dependence of the symmetry energy.

35 A×MeV 40Ar + 159Tb/197Au 反应中高激发核性质与反应机制研究

中能重离子碰撞的反应机制及其形成的高激发核的性质研究是当前中能重离子核物理研究的重要领域。本文通过对35 MeV/u~(40)Ar+~(159)Tb/~(197)Au反应中出射的轻粒子、中等质量碎片(IMF)和复合核裂变碎片的符合测量，研究了中等质量碎片的发射机制、类靶核的形成机制及其裂变时标、复合核的温度与激发能以及两者之间的关系等。利用前角探测器组的测量对前角区出射的IMF的单举和关联数据进行了分析。由弹核碎裂理论中的Gozdhaber关系式拟合了类弹碎片的能谱，由此提取的弹核的动量分布约化宽度为σ_0 ≈ 100MevV/c。通过Gemini模拟与IMF-IMF关联数据的对比揭示出激发的类弹碎片的裂变是关联IMF的一个重要来源。由IMF与裂变碎片以及IMF与后角轻粒子的关联数据显示出，在前角区域，当IMF的能量低于10 MeV/u时，复合核的蒸发对较轻IMF有较大的贡献；当IMF能量在10-24 MeV/u的区域时，IMF能量与复合核平均速度以及激发能之间存在着很强的依赖关系，说明这些IMF主要来源与弹靶之间的耗散反应；当IMF的能量超过24 MeV/u后，IMF能量与复合核平均速度以及激发能之间没有关联或关联很弱，说明在弹核碎裂的同时，靶核也发生了碎裂，它们共同贡献出部分核子形成了"中速源"或"颈部"。通过对复合核裂变时出射的关联裂片以及后角轻带电粒子的测量，提取了复合核的激发能以及在不同激发能能下所对应的核温度。对于中心碰撞，Au靶形成了E~* = 4MeV/u、T_(init) = 7.1 MeV的热核，Tb靶形成了E~* = 4.7MeV/u、T_(init) = 7.7MeV的热核。对其量热曲线的研究显示出，在当前入射能下没有观测到原子核液气相变的特征。由类弹碎片（PLF)与类靶核两个裂片的关联数据，提取了类靶核裂变轴在反应平面内的转动角度，并由此计算出类靶核的、裂变时标。在对称裂变时，类靶核的寿命约5 * 10~(-20) s，在非对称裂变（η =0.6）时降为约1.7 * 10~(-21) S。同时我们认为类靶核的裂变存在两种机制，即动力学裂变和统计裂变，分别对应于裂变轴在反应平面内的非各相同性分别和各相同性分布。

The regional types of China's floating population: Identification methods and spatial patterns

With the rapid increase of the number and influence of floating population in China, it is urgently needed to understand the regional types of China's floating population and their spatial characteristics. After reviewing the current methods for identifying regional types of floating population, this paper puts forward a new composite-index identification method and its modification version which is consisted of two indexes of the net migration rate and gross migration rate. Then, the traditional single-index and the new composite-index identification methods are empirically tested to explore their spatial patterns and characteristics by using China's 2000 census data at county level. The results show: (1) The composite-index identification method is much better than traditional single-index method because it can measure the migration direction and scale of floating simultaneously, and in particular it can identify the unique regional types of floating population with large scale of immigration and emigration. (2) The modified composite-index identification method, by using the share of a region's certain type of floating population to the total in China as weights, can effectively correct the over- or under-estimated errors due to the rather large or small total population of a region. (3) The spatial patterns of different regional types of China's floating population are closely related to the regional differentiation of their natural environment, population density and socio-economic development level. The three active regional types of floating population are mainly located in the eastern part of China with lower elevation, more than 800 mm precipitation, rather higher population densities and economic development levels.

温度对Ti_(45)Zr_(35)Ni_(20)合金电化学贮氢性能的影响

采用真空熔炼法制备了Ti45Zr35Ni20合金,研究了合金在不同温度下的电化学贮氢性能。结果表明,Ti45Zr35-Ni20电极的电化学性能随着温度而变化,温度从323 K升高到343 K时,电极的活化次数从22次减少到8次,放电容量从86.1 mAh/g增到135.0 mAh/g,快速放电能力也有所提高,然而,高温使电极的循环稳定性显著下降,自放电率增大。

Infrared spectroscopic study on thermal behavior of Langmuir-Blodgett films of octadecyl ammonium octadecanoate and octadecylammonium octadecanoate-d(35)

Langmuir-Blodgett (LB) films of octadecylammonium octadecanoate (C(18)H(37)j7NH(3)(+)C(17)H(35)COO(-),ODASA) and octadecylammonium octadecanoate-d(35) (C18H37+NH3+C17D35COO-, ODASA-d(53)) were prepared and their thermal behaviors were investigated by variable-temperature Fourier transform infrared transmission spectroscopy. It was found that the two hydrocarbon chains of ODASA molecule in LB films are highly ordered while that protonated (H) chain in ODASA-d(35) is partially disordered with some gauche conformers introduced at room temperature.