Fabrication of GaN-based LEDs with 22° undercut sidewalls by inductively coupled plasma reactive ion etching＊

We use a simple and controllable method to fabricate GaN-based light-emitting diodes （LEDs） with 22° undercut sidewalls by the successful implementation of the inductively coupled plasma reactive ion etching （ICP-RIE）. Our exper- iment results show that the output powers of the LEDs with 22° undercut sidewalls are 34.8 rnW under a 20-mA current injection, 6.75% higher than 32.6 mW, the output powers of the conventional LEDs under the same current injection.     

Influence of Si doping on the structural and optical properties of InGaN epilayers

Influences of the Si doping on the structural and optical properties of the InGaN epilayers are investigated in detail by means of high-resolution X-ray diffraction （HRXRD）, photolumimescence （PL）, scanning electron microscope （SEM）, and atomic force microscopy （AFM）. It is found that the Si doping may improve the surface morphology and crystal quality of the InGaN film and meanwhile it can also enhance the emission efficiency by increasing the electron concentration in the InGaN and suppressing tile formation of V-defects, which act as nonradiative recombination centers in the InGaN, and it is proposed that the former plays a more important role in enhancing the emission efficiency in the InGaN.     

Mixing MC events in a reactor neutrino experiment

In reactor neutrino experiments, the analysis of time correlations between different physical events is an important task. Such analysis can help to understand the physical mechanisms of the signal and background events as well as the details of event selection and background estimation. This study investigates a "sampling and mixing" method used for producing large MC data samples for the Daya Bay reactor neutrino experiment. We designed a simple, generic mixing algorithm and generated large MC data samples for physics analysis from several samples according to their respective event rates. Basic plots based on the mixed data are shown.     

运用线性约束条件解题两例

r|112、|.、r||zlwe|、由得例’已知’数二，一{ y簇x，x Zy毛4，则y)一2，s一扩 犷 Zx一Zy 2的最小值是( 9 tZ气)二二勺(B)2(C)3 ). (D)涯f(0)~Zb>0，f(l)=a Zb 1<0，f(2)一Za Zb 4>0，b)0，a Zb十1<0，a b 2>0.解画出满足不等式的可行域如图1所示. S一xZ 少， Zx一Zy 2~(x 1)’ (少一1)2的.y巍广”满热戮握袅‘4凛蘸瓢】瓢黔画出满足上述不等式组的平面区域如图2所示.解方程组图1 { a Zb l=0，a十b十2一O，几何意义是表示点A(一1，1)与可行域内的点的距离的平方，丫百的最小值为点A到直线y~x的距离福，从而S的最小值为2，故选(B…     

Technique for Monolithic Fabrication of Microlens Arrays Integrated with Infrared CCD

1　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｔｈｅｉｎｆｒａｒｅｄｃｈａｒｇｅｃｏｕｐｌｅｄｄｅｖｉｃｅ(ＩＲＣＣＤ )ｓｅｎｓｉｔｉｖｅｆｒｏｍ 3ｔｏ 5μｍｈａｓｎｕｍｅｒｏｕｓａｐｐｌｉｃａｔｉｏｎｓｉｎｂｏｔｈｍｉｌｉｔａｒｙａｎｄｃｉｖｉｌｉｎｄｕｓｔｒｉｅｓ[1] .Ｔｏ ｇｅｔｌａｒｇｅａｒｒａｙＩＲＣＣＤ ,ｒｅｃｅｎｔｔｒｅｎｄｓｉｎＩＲＣＣＤｔｅｃｈｎｏｌｏｇｙａｒｅｔｏｒｅｄｕｃｅｂｏｔｈ ｐｉｘｅｌｓｉｚｅａｎｄｔｈｅａｃｔｉｖｅａｒｅａ .Ｗｈｅｒｅａｓｔｈｅｆｏｒｍｅｒｉｎｃｒｅａｓｅｓａｒｒａ…     

问题170——关于等比数列的“分段和”：Sk，S2k-Sk，S3k-S2k，…组成的数列

该问题来稿十分踊跃，至本刊截稿时，共收稿29篇（看来还有来稿之势），均认为解法1结果正确，解法2结果错误．来稿前6名的作者是：南通高等师范学校王兴东，湖南省邵东县金龙南路95号黄旭明，内蒙李国梅，河南省上蔡一高王安寓，江苏省镇江中学陆建根，安徽省淮南市第三中学代银、南佳水（合稿）．     

Study of BESⅢ MUC offine software with cosmic-ray data

Cosmic-ray data of 90 M events have been collected and used for calibration,alignment as well as detector tuning. A special tracking algorithm for the BESⅢ muon counter is developed and verified with Monte-Carlo simulation and then further confirmed with the cosmic-ray data. The obtained strip resolutions are in good agreement with the design values. A new alignment approach for the BESⅢ muon counter is confirmed with the cosmic-ray data and proposed to be used in future analysis of experimental data.     

High-power ultraviolet 278-nm laser from fourth-harmonic generation of an Nd:YAG amplifier in CsB_3O_5 crystal

We report on the experimental investigation and theoretical analysis of a nanosecond pulse high power ultraviolet(UV) 278 nm laser by fourth-harmonic generation(FHG) of a 1112-nm Nd:YAG amplifier in LiB_3O_5(LBO) and CsB_3O_5(CBO) crystals. The UV laser delivers a maximum average power of 10.3 W at 278 nm with peak power of 36.8 k W under input pump power of 41 W at 556 nm. This is, to the best of our knowledge, the highest output power at the specific UV wavelength of 278 nm. We also performed the theoretical investigation on the FHG with a model in the Gaussian approximation of both spatial and temporal profiles, especially accounting for the two-photon absorption effect in CBO crystal for the first time. The average output power, pulse width, and beam spatial distribution of the UV laser were simulated. The theoretical calculations are in close agreement with the experimental results.     

基于丝网印刷工艺的安培型酶免疫传感器的研究

研究了一种一次性安培型免疫传感器,检测辣根过氧化物酶(HRP)。用丝网印刷工艺制备三电极结构的传感器,工作电极是碳电极,银电极是伪参比电极。采用电荷传递系数、评估厚膜电极的一致性。通过戊二醛交联法,把抗HRP酶抗体固定在电极表面。加入底物H2O2和电子介体邻苯二胺,分别用安培法和比色法进行检测和比较分析。安培法测定HRP的测量范围10μg/L~10 mg/L,检出限10μg/L;比色法测定范围为2~40 mg/L,检出限2 mg/L。同时分析了湿度对传感器寿命的影响。