50 resultados para 1828-1863


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新的2′×2′卫星测高获得的水深数据表明,除了在南海中央海盆扩张脊附近

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采用离子注入、离子沉积及后期退火方法制备了稀磁半导体单晶Mn_xGa_(1-x)Sb,在室温下(300 K)获得了单晶的磁滞回线。用X射线衍射方法分析了铁磁性半导体单晶Mn_xGa_(1-x)Sb的结构,用电化学C-V法分析了单晶的载流子浓度分布。由X射线衍射得知,Mn_xGa_(1-x)Sb中Mn含量逐渐由近表面处的x = 0.09下降到晶片内部的x = 0。电化学C-V测得单晶的空穴浓度高达1 * 10~(21)cm~(-3),表明Mn_xGa_(1-x)Sb单晶中大部分Mn原子占据Ga位,起受主作用。

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An experiment of Mg-22 and Ne-20 beams bombarding on a C-12 target at an energy of 60 similar to 70 A MeV has been performed at the RIKEN projectile fragment separator (RIPS)in the RIKEN Ring Cyclotron Facility to study the two-proton correlated emission from Mg-22 and Ne-20 excited states. The two-protons momentum correlation functions have been obtained for Mg-22 and Ne-20, respectively. The trajectories of the Mg-22 decayed products (Ne-20 + p + p) were also measured to get the angular correlations between the two protons in Center of Mass of decaying system by relativistic-kinematics reconstruction. The results exhibit that Mg-22 has the features of He-2 cluster decay mechanism.

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应用 GIS和 RS技术 ,运用 FRAGSTATS格局分析软件 ,从景观破碎度、分维数和分离度等综合分析了河西走廊武威绿洲的景观格局十多年的变化情况。并通过建立景观类型转移矩阵和转换图 ,详细描述了各类型间的转化情况。武威绿洲各项格局指数的变化都可表明人类影响不断加大 ,发生变化最大的在绿洲边缘地带。从人类活动和水资源的变化找到绿洲景观变化的驱动因子 ,并提出了可持续利用的对策。

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对长白山阔叶红松林 2 0 0 3年生长季的涡动相关实测时间序列进行了去倾修订与超声风速仪倾斜修订 ,并分析了不同修订方法对森林CO2 通量计算值的影响 .结果表明 ,基于未修订时间序列计算得到的森林CO2 通量 (Fcraw)被高估 .线性与非线性去倾对Fcraw的修订量分别为 1 6 %、1 8% ,两者差异很小 .平面拟合坐标变换与流线坐标变换对Fcraw的修订量分别为 3 7%、4 7% ,两者差异较大 .对线性去倾后的时间序列分别进行流线坐标变换与平面拟合坐标变换 ,二者对Fcraw的修订量分别为 5 5 %与 4 6 % .建议对时间序列进行线性去倾与平面拟合坐标变换综合修订 .