窄带空芯反谐振光纤的制备及其模式转换应用研究

空芯反谐振光纤由于其优异的光学特性,如低非线性、超低群速度色散、低温度敏感性和高损伤阈值等,使其在大功率激光传输、量子通信、传感、航空航天等多个领域有着潜在的应用,成为未来最具发展潜力的特种光纤.由于空芯反谐振光纤能够将99.9%以上光场限制在光纤的空芯区域中,这也使其成为光纤滤波器、模式转换等领域的重要光子器件.本文针对980 nm单模激光器的迫切需求,研制了一种应用于980 nm多模激光转980 nm单模激光的空芯反谐振光纤,并对其应用进行了实验验证.     

新产品成败因素多元分析

本文运用方差分析、 ｘ２检验、主成分分析、判别分析，对企业新产品开发成败问题进行了描述性实证研究，揭示了新产品成败的关联因素。研究结果说明，成功地开发新产品，就在于通过合理的开发步骤，开发出质量好创新大的新产品，适时投放到容量大需求强的市场。     

Electroluminescence from the InGaN/GaN Superlattices Interlayer of Yellow LEDs with Large V-Pits Grown on Si(111)

A blue emission originated from In GaN/GaN superlattice(SL) interlayer is observed in the yellow LEDs with V-pits embedded in the quantum wells(QWs), revealing that sufficient holes have penetrated through the QWs into SLs far away from the p-type layer. In the V-pits embedded LEDs, hole transport has two paths: via the flat c-plane region or via the sidewalls of V-pits. It is proved that the holes in SLs are injected from the sidewalls of V-pits, and the transportation process is significantly affected by working temperature, current density, and the size of V-pits. Four motion possibilities are discussed when the holes flow via the sidewalls. All these may contribute to a better understanding of hole transport and device design.     

掀起高考创新题目的"盖头"来——深入剖析高考试题,体会高考题目"创新点"

[问题背景]每年数学高考试题都会出现一些"创新题",这些题目,从形式上跳出已学知识的旧框架,在试卷中临时定义新背景、新知识,对于这类问题,大多考生有雾里看花的感觉,往往在考试中感到很大的阻力.     

侗乡瑶寨双飞凤珠坛教学姐妹花

上个世纪80年代中后期，在广西龙胜各族自治县里，有两个年青姑娘先后走进了小学教师的行列，一个是侗族姑娘蒙仙花，另一个是瑶族姑娘潘春艳。     

化学“单元程序教学法”的深化探研

现代教学论认为:教学的目的在于使学生掌握学科的知识结构,发展学生的智力和培养学生的能力。为此,就必须充分体现“教为主导,学为主体”,即在教师的启迪下,让学生亲自发现问题,探讨和解决问题。化学“单元程序教学法”正是在这种思想指导下产生的综合性教学法。     

具有四项的指数丢番图方程(III)

根据定理1, 2和3,求任何一个方程ax-by =n, ax by±az ±bw±1=0或ax ±by±az ±bw=0 (x,y,z,w∈0)的解都是很简单的,此处a,b是适合2a, b50的互素的两个整数,n是适合1n80000的整数.     

具有四项的指数丢番图方程(Ⅲ)

根据定理 １,２和 ３;求任何一个方程 ａ~ｘ－ｂ~ｙ＝ｎ,ａ~ｘｂ~ｙ±ａ~ｚ±ｂ~ｗ±１＝０ 或ａ~ｘ±ｂ~ｙ±ａ~ｚ±ｂ~ｗ＝０（ｘ,ｙ,ｚ,ｗ∈≥０）的解都是很简单的,此处ａ,ｂ是适合 ２ ≤５ ａ,ｂ≤５０的互素的两个整数,ｎ是适合１≤ｎ≤８００００的整数．     

Effect of AlGaN interlayer on luminous efficiency and reliability of GaN-based green LEDs on silicon substrate

The effect of AlGaN interlayer in quantum barrier on the electroluminescence characteristics of GaN-based green light emitting diodes(LEDs)grown on silicon substrate was investigated.The results show that AlGaN interlayer is beneficial to improve the luminous efficiency of LED devices and restrain the phase separation of In GaN.The former is ascribed to the inserted AlGaN layers can play a key role in determining the carrier distribution and screening dislocations in the active region,and the latter is attributed to the increased compressive stress in the quantum well.However,when the electrical stress aging tests were performed at a current density of 100 A/cm^2,LED devices with AlGaN interlayers are more likely to induce the generation/proliferation of defects in the active region under the effect of electrical stress,resulting in the reduced light output power at low current density.     

铜-钯复合催化膜在甲醇脱氢制甲酸甲酯的应用

研究了常压下甲醇脱氢制甲酸甲酯的膜催化反应．采用离子交换法制备的铜复合膜在１６０～２６０℃表现出较高的反应活性，２４０℃时甲醇转化率和甲酸甲酯收率分别为５７３％和５００％，而相应固定床反应器的甲醇转化率和甲酸甲酯收率分别为４３１％和３６９％．铜钯复合膜反应器能使反应选择分离同时进行，但产物甲酸甲酯的总收率不及铜复合膜．还对铜复合膜的制备条件作了初步探讨．