光纤光栅反射谱的放缩特性

利用介质光波导耦合模理论,证明了弱扰动的光纤光栅具有一个重要特性--放缩特性;即如果光纤光栅的折射率扰动分布沿光纤轴放大α倍,同时扰动强度缩小α倍,那么光栅的反射谱就以共振波长为中心在波长轴上缩小α倍.     

Effect of a rhombohedral phase on lithium intercalation capacity in graphite

Five natural graphites with different rhombohedral phase (3R phase) content have been investigated as anode materials for rechargeable lithium-ion batteries. The reversible capacity varies from 250 mA h/g to 350 mA h/g for the same intercalation conditions depending on the content of the 3R-phase. With increasing rhombohedral phase in the graphite, the intercalation capacity will be high. A peak at about 10 mV in the cyclic voltammograms (CV) of a sample with a large 3R-phase content is caused by lithium ions occupying boundaries between the rhombohedral (3R) phase and the hexagonal (2H) phase and is responsible for a capacity exceeding the theoretical value.     

稀土钻酸盐的电子和红外光谱研究

本文考察了具有钙钛矿型晶体结构的稀土钴酸盐LnCoO_3(Ln=La～Er)的电子和红外光谱,用晶体学和Ln-O,Co-O键的共价性讨论了实验结果,发现中心离子Co~(3+)的电子跃迁受到稀土离子Ln~(3+)的有规律的影响。LnCoO_3有其特定的CoO_6基团振动光谱,Ln-O的共价性随着稀土元素原子序数的增大而加强:重稀土的红外光谱比轻稀土更丰富,有的还出现分裂现象。用IR技术考察了制备等过程中晶体结构的变化。     

Mitrinovi -Djokovi 不等式的推广

本文中,我们把Mitrinovi -Djokovi 不等式推广成:若x_k>0(K=1,…,n),x_1+…+x_n=S≤n-2+2(2+5~(1/2))~(1/2),且a>0,则 sum from k=1 to n(x_k+1/x_k)~a≥n(s/n+n/s)~a。     

Ⅱ—Ⅵ族稀磁半导体Cd1—xMnxTe／Cd1—yMnyTe超晶格的光调制反 …

本文报道用分子束外延技术生长的Ｃｄ１－ｘＭｎｘＴｅ／Ｃｄ１－ｙＭｎｙＴｅ超晶格样品在８０Ｋ下的光调制反射谱实验结果，观测到１１Ｈ，２２Ｈ，３３Ｈ和１１Ｌ等激子跃迁结构。计及晶格失配导致的应力效应，对子能级结构进行了理论计算。     

The Second Law of Thermodynamic in Quantum System

The second law of thermodynamics is one of the most fundamental and for-reaching laws of physics. It teaches us that when a closed system undergoes a thermodynamic process the entropy of the system never decreases; it increases, or at least remains constant. If the entropy increases the thermodynamic process is irreversible, otherwise it is reversible. Only ideal thermal process is reversible. In classical world a great number of facts have proved the second law is true. But in quantum world since the quantum coherence and correlations exist we are not sure the second law is still true, at least in principle. This is because that： 1. on the microscopic level the irreversibility is conflict with the reversibility of all fundamental physical laws ; 2. there are not enough evidences to show it is true in quantum world.     

Isobar separation at FRS-ESR – a development towards pure isomeric stored beams

One important goal of the ILIMA project at FAIR is the study of masses and decay properties of relativistic isomeric beams stored and cooled in the planned storage-ring complex. A new scheme is described, where a storage-cooler ring is used for high-resolution mass separation. Experimental results on the separation of the isobaric pair ¹⁴⁰Pr-¹⁴⁰Ce are presented. P. Beller, deceased.     

界面动力学对过冷熔体中球晶生长界面形态的影响

考虑了在非平衡凝固条件下球晶生长过程中界面动力学系数随界面温度的变化,利用渐近分析方法求出了在过冷熔体中球晶生长温度场和界面的近似解析解,研究了非线性界面动力学过冷对于过冷熔体中球晶界面形态和生长速度的影响.研究表明,界面动力学系数越大,球晶的生长速度越快; 反之,表明界面动力学系数越小,球晶的生长速度越慢.与忽略界面动力学的情形比较,在球晶生长过程中依赖于界面温度变化的界面动力学显著地减缓了晶体生长的速度. 关键词： 球晶 界面形态 渐近分析     

原子吸收光谱法测定不同采收时间栽培与野生羌活药材中微量元素的含量

利用空气-乙炔火焰原子吸收光谱法测定了不同采收时问(5月、6月、7月、8月和9月)的野生与栽培宽叶羌活药材中微量元素Ca,Mg,Fe,Mn,Cu和Zn的含量,应用SPSS16.0分析软件对结果进行统计分析.结果发现:羌活药材含有丰富的微量元素,栽培与野生宽叶羌活药材中微量元素的含量均以Ca元素的含量最高,Cu元素含量最...     

光纤分布式扰动传感器中瑞利和受激布里渊散射光谱特性及其影响研究

针对光纤分布式扰动传感器长距离应用定位误差增大的问题,研究了传感器长距离光纤中的瑞利散射和受激布里渊散射的光谱特性及其对系统定位精度的影响.建立了长距离光纤中瑞利和受激布里渊散射的数学模型,通过仿真研究发现散射光波的杂波干涉和强度噪声会严重降低干涉仪的光学信噪比,从而导致定位误差.通过实验验证了仿真结果的正确性.研究结...