退火处理对SnO2薄膜光致发光性质的影响

实验研究表明,SnO2薄膜经过退火处理后其光致发光谱有明显的变化。在氧和氮两种不同气氛中进行热处理,其变化也有差异。这种变化主要是由于SnO2膜中氧空位和自由载流于浓度变化所致。     

A CHARACTERIZATION OF THE SOLUTIONS OF p－ORDER FEIGENBAUM＇S FUNCTIONAL EQUATION WITH TOPOLOGICAL ENTROPY 0

ＡＣＨＡＲＡＣＴＥＲＩＺＡＴＩＯＮＯＦＴＨＥＳＯＬＵＴＩＯＮＳＯＦｐ－ＯＲＤＥＲＦＥＩＧＥＮＢＡＵＭ＇ＳＦＵＮＣＴＩＯＮＡＬＥＱＵＡＴＩＯＮＷＩＴＨＴＯＰＯＬＯＧＩＣＡＬＥＮＴＲＯＰＹ０（廖公夫）￥ＬｉａｏＧｏｎｇｆｕ（Ｄｅｐｔ．ｏｆＭａｔｈ．，Ｊｉ...     

应用分形理论探讨炸药的撞击感度

 根据分形几何的周长-面积公式及线性回归原理,对TATB等六种炸药样品的落锤试验的分幅图像进行了图像处理和分形维数计算。从中发现,越钝感的炸药样品,分形维数越大。因此,可以认为,用炸药样品的分形维数来鉴别撞击感度是基本可行的。     

聚乙烯-碘化铯中子阴极的最佳化

本文的中子阴级由聚乙烯、导电基底(Al)和碘化铯二次电子发射体组成.文中建立了一个此中子阴级的新的物理模型,并采用Monte Carlo方法模拟了中子同阴极作用产生低能二次电子的物理过程.模拟得到的出射二次电子能谱和产额与实验结果和理论分析符合得较好.我们还得到了最大探测效率时各中子阴极组分的最佳厚度.     

Near Infrared Spectroscopy of the Cretaceous Red Beds in Inner Mongolia DongshengmiaoSCIEI北大核心CSCD

Take the cores and surface weathered soil from the Cretaceous red beds in the western of Dongshengmiao mine of Inner Mongolia and analysis with near-infrared spectroscopy. The result shows that near-infrared spectroscopy can identify mineral quickly through the characteristic absorption peaks of each group. The Cretaceous red beds in the western of Dongshengmiao mine is argillaceous cementation, it is mainly composed of quartz, feldspar, montmorillonite, illite, chlorite, muscovite etc, the mineral composition is mainly affected by the upstream source area. The clay mineral like montmorillonite water swelling and uneven drying shrinkage expands the original crack and creates new cracks, reduces its strength, which is the mainly reason of its disintegration. According to the composition of clay mineral, we speculate its weathering process is mainly physical weathering, the climate during the weathering is cold and dry. The results can not only improve the geological feature of the mining area, but also show that the near-infrared spectroscopy technology can analyze the mineral composition of soil and rock effectively on the basis of Mineral spectroscopy, which demonstrates the feasibility of the near-infrared spectroscopy can analyze minerals in soil and rock quickly, that shows the feasibility in geology study, provides new ideas for the future research of soil and rock.     

THE NONLINEAR SCHR?DINGER EQUATION AND THE CROSS-PHASE MODULATION IN ERBIUM-DOPED FIBER AMPLIFIERS

The nonlinear Schr$\ddot{o}$dinger equation(NLSE) in erbium-doped fiber(EDF) was obtained. The cross-phase modulation (XPM) in the erbium-doped fiber amplifiers (EDFA) was studied based on this NLSE and the rate equations. A more generalized form of the propagation equation in EDFA was obtained which included the phase shifts the EDFA induced. An analytical expression was given to the XPM in the EDFA. It was found that the XPM in the EDFA dose not change very much with the wavelength except at the neighboring wavelengths (around 1531 nm) where the absorption and emission cross-sections of the erbium ions reach their maxima, and the XPMs have opposite signs on the two sides around 1531 nm. Furthermore, it was found that the XPM increases with the increase of the length of EDF.     

NxHy-Fe(x=0～2,y=0～3)配位簇的DFT计算

采用杂化密度泛函（ＤＦＴ）之Ｂ３ＬＹＰ／６－３１１Ｇ＊＊方法研究了ＮｘＨｙ－Ｆｅ（ｘ＝０～２,ｙ＝０～３）配位簇的几何结构和振动光谱,讨论了在纯铁催化剂上,氮分子和氢分子逐步合成氨的反应机理,结果表明,合成氨过程可能经历Ｎ２和Ｎ２Ｈ２物种,在优化结构的基础上,计算了各个模型的振动频率并解释了有关实验结果。     

基于分数阶流变模型的铁基块体非晶合金黏弹性行为研究

采用分数阶黏弹单元替代经典模型中的黏壶, 结合非晶合金在外加载荷作用下的微观结构演化, 建立了以分数阶微积分表示的非晶合金黏弹性本构模型. 并根据Hertz弹性理论及分数阶黏弹性本构模型, 推导了块体非晶合金在纳米压痕球形压头下的位移与载荷及时间关系式. 基于推导的解析式, 对铁基块体非晶合金在表观弹性区的纳米压痕位移与载荷及时间曲线进行了非线性拟合分析. 相较于整数阶模型, 分数阶模型不仅具有较高的拟合精度, 其拟合参数能敏锐地反应加载速率对块体非晶合金黏弹性行为的影响, 且参数的变化规律与载荷作用下非晶合金微观结构演化呈现出较强的相关性.     

Nd:YAG陶瓷与单晶4F3/2–4I13/2跃迁的弱谱线多波长激光性能对比

报道了基于半导体激光端面抽运Nd:YAG的⁴F_3/2–⁴I_13/2 跃迁的弱谱线多波长激光输出. 实验对比了透明陶瓷与单晶材料的激光输出特性, 表明透明陶瓷和单晶材料荧光谱强度的略微差异, 导致了多波长输出时相同两个波长之间的激光强度比在两种材料中的差异. 基于两种耦合输出镜片, 激光阈值都在2 W左右. 在13.5 W的抽运功率下, 基于Nd:YAG透明陶瓷获得了输出功率4.05 W、强度比1 :2的1338与1356 nm双波长激光和输出功率3.65 W、强度比13 : 1的1356与1414 nm 双波长激光, 斜率效率分别达33.9% 和31.9%.     

复杂地理环境的图像分割及电波传播特性

复杂地理环境是电波传播不可避免的传播环境,不仅不规则地形会对电波传播产生影响,不同的地表媒质对电波传播也会产生不同的影响。为了使得电波传播特性的预测结果更加地准确有效,通过图像分割算法实现地表环境的简单分类,同时对不同的媒质赋予不同的电磁参数,并结合数字高程模型（DEM)数据,实现了既具有地形起伏信息又具有地表电磁环境参数的复杂地理环境建模。在此基础上,对地表电磁环境信息做了网格剖分处理,利用抛物方程（PE）模型对复杂地理环境下的电波传播特性进行了预测。