几种草酸铁络合物体系光降解酞酸酯比较研究

文章在比较研究了几种草酸铁络合物体系对两种酞酸酯 DBP 和 DEHP 的光催化降解情况。结果表明：草酸铁络合物和草酸铁络合 物／H_2O_2体系在遮光条件下对 DBP 和 DEHP 没有降解作用。在中性 pH 值条件下，DBP 和 DEHP 在几种反应体系中的降解速率依次为：UV/草 酸铁络合物/H_2O_2＞UV/H_2O_2＞UV/草酸铁络合物＞UV＞太阳光/草酸铁络合物。UV 与草酸铁络合物对 DBP 和 DEHP 光降解的协同作用不 强，增强因子 f 分别为1． 20和1． 07。UV、草酸铁络

Molecular cloning of growth hormone receptor (GHR) from common carp (Cyprinus carpio L.) and identification of its two forms of mRNA transcripts

The cDNA of growth hormone receptor (GHR) was cloned from the liver of 2-year common carp (Cyprinus carpio L.) by reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA end (RACE). Its open reading frame (ORF) of 1806 nucleotides is translated into a putative peptide of 602 amino acids, including an extracellular ligand-binding domain of 244 amino acids (aa), a single transmembrane domain of 24 aa and an intracellular signal-transduction domain of 334 aa. Sequence analysis indicated that common carp GHR is highly homologous to goldfish (Carassius auratus) GHR at both gene and protein levels. Using a pair of gene-specific primers, a GHR fragment was amplified from the cDNA of 2-year common carp, a 224 bp product was identified in liver and a 321 bp product in other tissues. The sequencing of the products and the partial genomic DNA indicated that the difference in product size was the result of a 97 bp intron that alternatively spliced. In addition, the 321 bp fragment could be amplified from all the tissues of 4-month common carp including liver, demonstrating the occurrence of the alternative splicing of this intron during the development of common carp. Moreover, a semi-quantitative RT-PCR was performed to analyze the expression level of GHR in tissues of 2-year common carp and 4-month common carp. The result revealed that in the tissues of gill, thymus and brain, the expression level of GHR in 2-year common carp was significantly tower than that of 4-month common carp.

Sonar gain control in echolocating finless porpoises (Neophocaena phocaenoides) in an open water (L)

Source levels of echolocating free-ranging Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis) were calculated using a range estimated by measuring the time delays of the signals via the surface and bottom reflection paths to the hydrophone, relative to the direct signal. Peak-to-peak source levels for finless porpoise were from 163.7 to 185.6 dB re:1 mu Pa. The source levels are highly range dependent and varied approximately as a function of the one-way transmission loss for signals traveling from the animals to the hydrophone. (c) 2006 Acoustical Society of America.

EPITAXIAL LATERAL OVERGROWTH OF GaN ON SILICON-ON-INSULATOR

From a single process, GaN layers were laterally overgrown on maskless stripe-patterned (111) silicon-on-insulator (SOI) substrates by metalorganic chemical vapor deposition. The influence of stress on the behavior of dislocations at the coalescence during growth was observed using transmission electron microscopy (TEM). Improvement of the crystallin equality of the GaN layer was demonstrated by TEM and micro-Raman spectroscopy. Furthermore, the benefits of SOI substrates for GaN growth are also discussed.

Growth and characterization of AlGaN/AlN/GaN HEMT structures with a compositionally step-graded AlGaN barrier layer

A new AlGaN/AlN/GaN high electron mobility transistor (HEMT) structure using a compositionally step-graded AlGaN barrier layer is grown on sapphire by metalorganic chemical vapour deposition (MOCVD). The structure demonstrates significant enhancement of two-dimensional electron gas (2DEG) mobility and smooth surface morphology compared with the conventional HEMT structure with high Al composition AlGaN barrier. The high 2DEG mobility of 1806 cm(2)/Vs at room temperature and low rms surface roughness of 0.220 nm for a scan area of 5 mu m x 5 mu m are attributed to the improvement of interfacial and crystal quality by employing the step-graded barrier to accommodate the large lattice mismatch stress. The 2DEG sheet density is independent of the measurement temperature, showing the excellent 2DEG confinement of the step-graded structure. A low average sheet resistance of 314.5 Omega/square, with a good resistance uniformity of 0.68%, is also obtained across the 50 mm epilayer wafer. HEMT devices are successfully fabricated using this material structure, which exhibits a maximum extrinsic transconductance of 218 mS/mm and a maximum drain current density of 800 mA/mm.

国内外海洋热能转换概况

一、前言海洋热能转换(Ocean Thermal Energy Conversion OTEC)这一概念早在1881年法国物理学家 D~1 Arsonval 就提出来了。他设想在热带海洋表面温海水与深层冷海水之间，设置闭式朗肯循环，把海洋中所储存的太阳热能转换为电能。为实现这一设想，D~1Arsonval 的学生，法国工程师 G.Claude 于1926年在一个海水温差发电的模拟装置上使

南海表层沉积物与水柱中沉降颗粒物对比研究及其古环境再造意义

分析了南海62个表层沉积物样品中生源（有机质、碳酸钙和蛋白石）和非生源

Characterization of recombination centres in n-type Hg1-xCdxTe

The defect levels in Hg1-xCdxTe P+N junction photodiodes (x = 0.4) were first studied using deep-level transient spectroscopy. Two electron traps, E(1)(0.06) and E(2)(0.15), and two hole traps, H-1(0.075) and H-2(0.29), were obtained, Characteristic parameters-the minority lifetime of the devices and the dynamic resistance-area product at zero bias-are estimated according to these levels. Results show that these two minority levels may be important in controlling lifetime. We have studied the recombination mechanism of the hole trap H-2(0.29) further. It has a large activation energy and satisfies the formula sigma(T) = sigma(x) exp(-E(F)/E(T)). This reflects the fact that its recombination mechanism is multiphonon nonradiative recombination, which is rarely reported in narrow-bandgap materials.

高密度排列大功率垂直腔面发射激光器列阵

报道了980nm高密度排列大功率垂直腔面发射激光器列阵的研制.列阵单元为蜂窝状密堆积排列,单元台面直径为70μm,氧化孔径为30μm,相邻单元间隔为100μm.制作了含7,19,37个单元的列阵,讨论了它们的阈值电流和远场特性.在室温连续工作条件下,3种列阵的最大输出功率分别为0.26,0.5和0.6W.其中含37个单元的列阵在6A脉冲电流(脉宽30μs,重复频率100Hz)激发下,输出功率达到1.4W.

Si（113）表面原子结构的低能电子衍射研究

于2010-11-23批量导入

长白植物区维管束植物多样性及其格局研究

本文应用植物区系分析、数量分类（TWINSPAN）、相似性比较和生物多样性指数评估等方法对长白植物区维管束植物多样性及其格局进行了比较系统的研究。 本文对长白植物区维管束植物区系研究表明，本区共有维管束植物142科624属1881种，此区系属于温带性质，地理联系广泛，与东亚其它地区特别是与日本的联系最为密切。 通过对本区物种多样性的水平分布格局研究，提出了全区86县市的植物组成、分化指数、Shannon-Wiener指数、G－F指数和物种重要值IM的分布格局，并着重对本区六大山地和二大平原的物种多样性进行了分析，指出本区长白山植物分布最为集中。长白山、辽东山地、小兴安岭和张广才岭是本区植物多样性较高的地区。长白山、辽东山地和小兴安岭是本区物种分化中心。 对本区代表性山地长白山的物种多样性垂直分布格局研究表明，各植被垂直带的物种多样性指数（G-F指数）随海拔升高而递减。随海拔增高，温带性质的区系成分逐渐减弱，寒带亚寒带性质成分逐渐增强。热带性质的成分只影响到阔叶红松林带和暗针叶林带。 本文的对长白植物区重要山地阔叶红松林的物种多样性做了对比研究，提出长白山的阔叶红松林物种丰富度最高。各主要山地的多样性指数没有随纬度变化而呈单一升降关系。TWINSPAN 以属为单位的聚类结果表明，本区阔叶红松林的24个样地可以分为7个类型，阔叶红松林中的33个乔木树种划分为8个关联组。 本文提出了一种用于大尺度多样性评估的方法——物种重要值比较法。这种方法计算简便，结果可靠，对于改善目前大尺度生物多样性评价方法较少的状况有积极意义。此外本文首次将G－F指数引入植物多样性研究领域，并对G－F指数、Shannon-Wiener指数和IM值的测度结果进行评估，确认F指数和IM值的测度结果最令人满意。