A Single Mode 980nm InGaAs/GaAs/AlGaAs Large Optical Cavity Quantum Well Laser with Low Vertical Divergence Angle

To achieve high optical power as well as low vertical divergence angle, a new kind of optimized large optical cavity (LOC) structure is applied to a ridge waveguide 980nm InGaAs/GaAs/AlGaAs multi-quantum well laser. The optical power density in the waveguide is successfully reduced. The maximum output power is more than 400mW with a slope efficiency of 0.89W/A and the far-field vertical divergence angle is lowered to 23°.

Formation mechanism of defects in annealed InP

Dynamical formation mechanism of defects in the annealed nominally undoped semi-insulating InP obtained by high pressure, high temperature annealing of high purity materials is proposed. Local vibrational modes in tenths of InP samples reveal clearly existence of complexes related to hydrogen. Complexes of vacancy at indium site with one to four hydrogen atoms and isolated hydrogen or hydrogen dimers, complexes of hydrogen with various impurities are investigated by FTIR. Hydrogen can acts as an actuator for generation of antistructure defects. Fully hydrogenated indium vacancy dissociates leaving large lattice relaxation behind, deep donors, mainly larger complexes involving phosphorus at indium site and isolated hydrogen defects are created in nominally undoped InP after annealing. Also created are acceptor levels such as vacancy at indium site. Carrier charge compensation mechanism in nominally undoped InP upon annealing at high temperature is given. Microscopic models of hydrogen related defects are given. Structural, electronic and vibrational properties of LVMs related to hydrogen as well as their temperature effect are discussed.

Optical anisotropy of InAs submonolayer quantum wells in a (311) GaAs matrix

The steplike density of states obtained from reflectance-difference spectroscopy demonstrates that ultrathin InAs layers should be regarded as two-dimensional quantum wells rather than isolated clusters, even for the sample with only 1/3 monolayer InAs in (311)-oriented GaAs. The degree of anisotropy is within the intrinsic anisotropy of (311)-oriented ultrathin quantum wells, indicating that there is little structural or strain anisotropy in the InAs islands. (C) 1998 Elsevier Science B.V.

地下结构的爆炸振动效应与冲击破坏行为研究

对爆源近区地下混凝土管道结构在爆炸冲击载荷作用下的动力学响应开展探索性实验研究。选用钢筋混凝土管道模拟地下结构，尺寸为：$\phi_{\hbox{内}}$800mm$\times$2000mm$\times$100mm。通过实验研究定量确定爆炸振动波载荷对地下结构产生的振动效应；定性确定爆炸冲击波载荷对地下管道结构和混凝土材料产生的动态破坏效应。爆炸当量分别为50 g和100 g TNT，爆炸距离取为0.1，0.3，1，7和10m。实验主要涉及地下管道结构在小药量爆炸点近区的破坏效应与爆炸药量和爆炸距离间关系的确定；混凝土材料破坏行为与药量和爆炸距离关系的确定；爆炸冲击波的影响范围以及爆炸振动波的有效影响范围与爆源特性的关系及爆炸响应函数的确定。从小当量地下结构爆炸实验观察到：地下结构的爆炸振动响应，即振动波波长和频率不同于土介质地表的波长和频率。与地表面上建筑物的波长和频率相比，振动波长持续作用时间明显缩短，且振动频率显著提高。这与地下结构的爆炸动力学响应，特别是爆源近距离的结构动力学响应存在着本质的区别。不同的爆炸距离和当量，地下爆炸对地下结构可以产生振动和冲击两种不同特征的动力学效应。在折算距离大于0.22$\sim$0.25 m/W$^{1/3}$时，100 g TNT当量的爆炸以产生振动效应为主。在折算距离小于0.22$\sim$0.25 m/W$^{1/3}$时，爆炸主要产生冲击效应；在爆炸距离小于1.5m/W$^{1/3}$时，地下爆炸振动波对结构产生的动力学响应的明显特征是管道结构发生径向变形。而且，管道上与爆源最近点是管道变形的对称点。管道的轴向和环向动力响应表现为相应方向上的刚体振动。在爆炸距离大于1.5 m/W$^{1/3}$，如等于2.15m/W1/3的情况下，爆炸振动波对管道结构产生的动力学响应主要表现为整体振动。结构的变形特征基本消失；地下爆炸冲击波载荷对爆源近区管道结构和混凝土材料可以产生三种破坏效应：在折算距离等于0.065 m/W$^{1/3}$时，低强度的冲击波载荷仅产生结构破坏效应。实验中观察到混凝土管道只沿其轴线方向上形成贯穿性裂纹，管道内外表面均无损伤和破碎现象；当折算距离等于0.027 m/W1/3时，较强冲击波载荷既引起管道的结构破坏，也产生混凝土材料的破坏。这时观察到沿混凝土管道轴线方向上，以及与轴线成30$^\circ$至50$^\circ$范围内形成贯穿性裂纹。同时在管道内表面出现直径约为210 mm的层裂区，最大层裂厚度约为8$\sim$12 mm；当折算距离等于0.022 m/W$^{1/3}$时，爆炸强冲击波载荷主要引起的混凝土材料破坏形式表现为破碎。即在管道上以爆源最近点为中心形成直径约为370 mm的贯穿性孔洞，还观察到该孔洞周边不同方向上有长度为230$\sim$410 mm不等的数条细裂纹形成。

钮子瓜和袋花忍冬的化学成分研究

钮子瓜（Zehneria maysorensis Arn.）是一种常用的中草药，其性味苦、凉，主要功效为清热利湿、散风止痛，主治膀胱炎、头痛。体外活性筛选实验表明，袋花忍冬（Lonicera saccata Rehd.）95%乙醇提取物的乙酸乙酯部分对血管紧张素转化酶显示较强的抑制活性。为明确钮子瓜的药用物质基础和袋花忍冬中具有ACE抑制活性的成分，首次对两个植物的成分进行了研究。 1. 从钮子瓜95%乙醇提取物中主要通过色谱方法首次分离了14个化合物，通过波谱方法鉴定为(2S,3S,4R,10E)-2-[(2R)-2-羟基二十四烷酰基氨基]-10-十八烷-1,3,4-三醇（1）、(2S,3S,4R)-2-二十四烷酰基氨基-十八烷-1,3,4-三醇 （2）、胡萝卜苷（3）、swertish （4）、苯甲酸（5）、水杨酸（6）、loliolide （7）、胸腺嘧啶（8）、尿嘧啶（9）、(23Z)-9,19-环阿尔廷-23-烯-3β,25-二醇（10）、(20S,22E,24R)-5α,8α-表二氧-麦角甾-6,22-二烯-3β-醇（11）、十六烷酸 1-甘油酯（12）、大豆脑苷Ⅰ（13）和(22E,24S)-24-甲基-5α-胆甾-7,22-二烯-3β,5α,6β-三醇（14）。其中化合物4为一黄酮碳苷，具有旋转异构现象，有止痛作用；化合物6具有抗炎、镇痛、减热的活性，它们可能是钮子瓜药用物质基础的一部分。 2. 从袋花忍冬95%乙醇提取物中首次分离并鉴定了16个已知化合物：胡萝卜苷（3）、(20S,22E,24R)-5α,8α-表二氧-麦角甾-6,22-二烯-3β-醇（11）、十六烷酸 1-甘油酯（12）、E-p-coumaryl behenate (15)、谷甾醇（16）、2,6-dihydroxyhumula-3(12), 7(13),9(E)-triene (17)、环阿尔廷-25-烯-3β,24ξ-二醇 (18)、二十四烷酸 (19)、2,4-二羟基-3,6-二甲基苯甲酸甲酯 (20)、乌苏酸 (21)、柚皮素 (22)、木犀草素 (23)、柏双黄酮（24）咖啡酸 (25)、洋芹素（26）和木犀草素-7-O-β-D-葡萄糖苷 (27)。其中木犀草素（23）和咖啡酸（25）含量较高，它们为抑制ACE活性的成分。 3．综述了黄酮碳苷的旋转异构现象。 Zehneria maysorensis is a folk medicine for the treatment of cystitis and headache. The ethyl acetate soluble fraction of the 95% ethanol extract of Lonicera saccata showed obvious ACE inhibitory activity in vitro. To reveal their active constitutents, they were subjected to chemically study. From the 95% ethanol extract of the whole plants of Zehneria maysroensis fourteen compounds were isolated for the first time. On the basis of spectral data and/or by comparison with authentic samples, they were characterized to be (2S,3S,4R,10E)-2-[(2R)-2-hydroxytetracosanoylamino]-10-octadecene-1,3,4-triol (1), (2S,3S,4R)-2-tetracosanoylamino-1,3,4-octadecanetriol (2), daucosterol (3), swertish (4), benzoic acid (5), salicylic acid (6), loliolide (7), thymine (8), uracil (9), (23Z)-9,19-cycloart-23-ene-3β,25-diol (10), (20S,22E,24R)-5α,8α-epidioxy-ergosta- 6,22-diene-3β-ol (11), 2,3-dihydroxypropyl hexadecoate (12), soya-cerebroside (13) and (22E,24S)-24-methyl-5α-cholesta-7,22-diene-3β,5α,6β-triol (14). Compound 4, a C-glycosylflavone, showed a very interesting rotational isomerism. Compounds 4 and 6 may be the active constituents of Zehneria maysorensis considering their sedative and anti-inflammation activity, respectively. From the whole plants of Lonicera saccata, sixteen compounds were isolated for the first time. On the basis of spectral data and/or by comparison with authentic samples, they were identified to be daucosterol (3), (20S,22E,24R)-5α,8α-epidioxy- ergosta-6,22-diene-3β-ol (11), 2,3-dihydroxypropyl hexadecoate (12), E-p-coumaryl behenate (15), β-sitosterol (16), 2,6-dihydroxyhumula-3(12),7(13),9(E)-triene (17), cycloart-25-ene-3β,24ξ-diol (18), tetracosanoic acid (19), methyl 2,4-dihydroxy- 3,6-dimethylbenzoate (20), ursolic acid (21), naringenin (22), luteolin (23), cupressuflavone (24), caffeic acid (25), apigenin (26) and luteolin-7-O-β-D- glucopyranoside (27). Luteolin (23) and caffeic acid (25) were the ACE inhibitory active constituents. Rotational isomerism for C-glycosylflavonoid was reviewed.

兰州放射性次级束流线数据获取系统的改造

为兰州放射性次级束流线(RIBLL)实验需求升级改造1套基于PC-Linux的数据获取系统。系统采用PCI-CAMAC总线标准,CAMAC插件与计算机间的通讯通过CC32机箱控制器和PCIADA卡来实现。数据在线分析程序可直接连接CERN的PAW/ROOT分析平台。经多次实验检验,系统工作稳定可靠,最大数据获取速率达到了930 KB/s。

快重离子在聚合物潜径迹中引起的损伤效应研究

在室温和真空环境下利用不同的快重离子(1.158GeV Fe56、1.755GeV Xe136及2.636GeV U238)对多层堆叠的聚对苯二甲酸乙二醇酯(PET)、聚碳酸脂(PC)和聚酰亚胺(PI)进行了辐照,结合X射线衍射(XRD)、傅立叶红外光谱(FTIR)及紫外可见光谱测量技术,在较宽的电子能损(1.9-19.0 keV·nm-1)和注量范围(1×1010-6×1012 cm-2)研究了离子在不同聚合物潜径迹中引起的损伤过程,观测到了主要官能团的降解、炔基生成、非晶化及紫外吸收边缘的红移等现象随辐照注量及电子能损的变化趋势。通过对损伤过程的定量分析,应用径迹饱和模型假设,分别给出了Fe、Xe和U离子在不同电子能损下辐照PC时的平均非晶化径迹半径和炔基形成半径,并用热峰模型对实验结果进行了检验。