深能级缺陷对半绝缘InP材料电学补偿的影响

对铁掺杂和高温退火非掺杂磷化铟制备的两种半绝缘材料的电学补偿和深能级缺陷进行了分析和比较．根据热激电流谱（TSC）测得的深能级缺陷结果，分析了这两种半绝缘InP材料中深能级缺陷对电学补偿的影响．在掺铁半绝缘InP材料中，由于存在高浓度的深能级缺陷参与电学补偿。降低了材料的补偿度和电学性能．相比之下，利用磷化饫气氛下高温退火非掺InP获得的半绝缘材料的深能级缺陷浓度很低，通过扩散掺入晶格的铁成为唯一的深受主补偿中心钉扎费米能级，材料表现出优异的电学性质．在此基础上给出了一个更为广泛的半绝缘InP材料的电学补偿模型．

Optimized logarithmic phase masks used to generate defocus invariant modulation transfer function for wavefront coding system

In a previous Letter [Opt. Lett. 33, 1171 (2008)], we proposed an improved logarithmic phase mask by making modifications to the original one designed by Sherif. However, further studies in another paper [Appl. Opt. 49, 229 (2010)] show that even when the Sherif mask and the improved one are optimized, their corresponding defocused modulation transfer functions (MTFs) are still not stable with respect to focus errors. So, by further modifying their phase profiles, we design another two logarithmic phase masks that exhibit more stable defocused MTF. However, with the defocus-induced phase effect considered, we find that the performance of the two masks proposed in this Letter is better than the Sherif mask, but worse than our previously proposed phase mask, according to the Hilbert space angle. (C) 2010 Optical Society of America

Performance of an improved logarithmic phase mask with optimized parameters in a wavefront-coding system

In two papers [Proc. SPIE 4471, 272-280 (2001) and Appl. Opt. 43, 2709-2721 (2004)], a logarithmic phase mask was proposed and proved to be effective in extending the depth of field; however, according to our research, this mask is not that perfect because the corresponding defocused modulation transfer function has large oscillations in the low-frequency region, even when the mask is optimized. So, in a previously published paper [Opt. Lett. 33, 1171-1173 (2008)], we proposed an improved logarithmic phase mask by making a small modification. The new mask can not only eliminate the drawbacks to a certain extent but can also be even less sensitive to focus errors according to Fisher information criteria. However, the performance comparison was carried out with the modified mask not being optimized, which was not reasonable. In this manuscript, we optimize the modified logarithmic phase mask first before analyzing its performance and more convincing results have been obtained based on the analysis of several frequently used metrics. (C) 2010 Optical Society of America

CSRe团簇内靶的真空与分子泵监测系统的设计

介绍了国家重大科学工程项目——兰州重离子加速器冷却存储环(HIRFL-CSR)的实验环(CSRe)团簇内靶真空与分子泵监测系统。该系统主要通过一个应用程序获取各真空规及分子泵的状态值,并存入、更新Oracle数据库。浏览器上的ActiveX从Oracle中读取各设备状态值进行显示,如果状态值在警戒范围,则做出相应的控制操作。该系统在实验测试中运行良好,能满足实验的要求。

原子吸收光谱法测定膜荚黄芪不同器官矿质元素含量

应用混合酸HNO3-HClO4(4∶1)在常压微沸条件下对膜荚黄芪根系及茎叶样品进行消解,采用原子吸收光谱法测定了膜荚黄芪不同器官即根及茎叶中五种人体必需矿质元素K,Fe,Zn,Mn和Cu含量,并对结果进行了统计分析与比较。该方法标准曲线相关系数为0.997 3~0.999 9,加标回收率为92.88%~109.25%,相对标准偏差(RSD,n=5)为0.393 5%~3.175 2%。方法简单,结果可靠。结果显示,膜荚黄芪根及茎叶中5种矿质元素含量顺序均为K>Fe>Zn>Mn>Cu。膜荚黄芪不同器官矿质元素含量不同,根中富含Fe,Zn,Cu元素,根内Fe含量是茎叶的1.54倍。茎叶中也含有丰富的矿质元素,特别是K和Mn元素。茎叶中K含量是根的1.63倍,这与黄芪的药效相符合。试验结果将为研究矿质元素在黄芪植株中的分布以及矿质元素含量与黄芪药效相关性提供理论依据。

低温下光照对黄瓜叶片光合特性的影响

为揭示低温下光照对黄瓜光合作用的影响，在叶片水平对５℃ １００μｍｏｌｍ·－’·ｓ－１和５℃黑暗处理４ｈ后黄瓜叶片光合－光响应和光合－ＣＯ２响应进行了对比研究、结果表明，５℃黑暗处理４ｈ使黄瓜叶片光饱和光合速率、表观光量子效率、ＣＯ２饱和光合速率以及梭化效率分别降低 ２２．５％、２８．０％、３１．３％和 ３７．２％，５℃ １００μｍｏｌ·ｍ－２·ｓ－１使上述指标分别降低 ５６．１％、６１．０％、５４．０％和 ５４．３％，说明 １００μｍｏｌ·ｍ－２·ｓ－１光照明显加剧５℃低温对黄瓜叶片光合功能的伤害。进一步研究结果显示低温光照处理使黄瓜叶片 ＰＳⅡ光合中心受到较严重的光抑制，类囊体跨膜质子梯度显著降低。对低温下光照对黄瓜叶片光合作用具有不良作用的原因进行了讨论。

小叶锦鸡儿防风固沙林稳定性研究

针对科尔沁沙地小叶锦鸡儿固沙林在持续高温干旱条件下出现稳定性波动的问题 ,选择 2、5、15、35 a人工群落和天然群落进行对比研究 ,探讨了人工小叶锦鸡儿防风固沙林物种多样性在 35 a间的变化以及对大气持续干旱的抵抗力和对外界干扰的恢复能力。流动沙丘固定后 ,固沙林内草本植物迅速侵入 ,其后则缓慢发展并处于相对稳定状态 ,植物种类数保持在 2 0～ 2 3种。但在人工固沙群落中 1年生植物在种类数和数量上始终处于优势地位 ,而天然群落则是多年生植物占优势。人工固沙群落物种多样性指数逐年提高 ,但明显低于天然群落。在受到大气持续高温干旱的干扰时 ,人工群落土壤条件极度恶化 ,出现了明显的干沙层 ,最深达 14 0 cm ,叶片含水量极度降低 ,植物生长停止。沙地植物群落对牲畜取食均具有一定的补偿的能力 ,在啃食较轻时表现为超补偿现象。通过建立数学模型分析 ,人工群落个体的补偿点和超补偿点明显低于天然群落。采用冗余理论对植物群落稳定性机制进行了论述 ,认为冗余结构的变化是导致群落稳定性变化的内在原因。对现有人工小叶锦鸡儿固沙林的稳定性进行了评价 ,并认为 15 a左右人工固沙林正处于相对稳定并缓慢发展状态。对于稳定的人工固沙群落应具备以下条件 :(1)适于当地环境条件 ;(2 )对外界