Creation and suppression of point defects through a kick-out substitution process of Fe in InP

Indium antisite defect In-P-related photoluminescence has been observed in Fe-diffused semi-insulating (SI) InP. Compared to annealed undoped or Fe-predoped SI InP, there are fewer defects in SI InP obtained by long-duration, high-temperature Fe diffusion. The suppression of the formation of point defects in Fe-diffused SI InP can be explained in terms of the complete occupation by Fe at indium vacancy. The In-P defect is enhanced by the indium interstitial that is caused by the kick out of In and the substitution at the indium site of Fe in the diffusion process. Through these Fe-diffusion results, the nature of the defects in annealed undoped SI InP is better understood. (C) 2002 American Institute of Physics.

Liquid nitrogen flowrate alarm system for MBE

Liquid nitrogen is very important for MBE system. Most MBE systems use the liquid nitrogen to absorb the impurity molecules. If MBE cryoshroud is lack of liquid nitrogen, the pressure of the growth chamber will grow. This will affect the film quality. But too much liquid nitrogen is a waste. We have developed a liquid nitrogen flowrate alarm system to monitor the liquid nitrogen status in MBE cryoshroud. In this method, a temperature sensor is placed at the end of the cryoshroud. The temperature varies with changing of the liquid nitrogen status in cryoshroud. If the liquid nitrogen level in the cryoshroud is too low or too high, the LNFA will send out an alarm to warn the user to adjust the liquid nitrogen flowrate. In our experiments, we found this method works well, and the temperature responds sensitively. With the help of this system, people can view the liquid nitrogen status of the entire growth process. Compare with other method. it is very cheap.

Diffractive Grating Based Out-of-Plane Coupling between Silicon Nanowire and Optical Fiber

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Period Continuous Tuning of an Efficient Mid-Infrared Optical Parametric Oscillator Based on a Fan-out Periodically Poled MgO-Doped Lithium Niobate

We report a period continuously tunable, efficient, mid-infrared optical parametric oscillator (OPO) based on a fan-out periodically poled MgO-doped congruent lithium niobate (PPMgLN). The OPO is pumped by a Nd:YAG laser and a maximum idler output average power of 1.65 W at 3.93 mu m is obtained with a pump average power of 10.5 W, corresponding to the conversion efficiency of about 16% from the pump to the idler. The output spectral properties of the OPO with the fan-out crystal are analyzed. The OPO is continuously tuned over 3.78-4.58 mu m (idler) when fan-out periods are changed from 27.0 to 29.4 mu m. Compared with temperature tuning, fan-out period continuous tuning has faster tuning rate and wider tuning range.

Electron concentration dependence of exciton localization and freeze-out at local potential fluctuations in InN films

InN films with electron concentration ranging from n similar to 10(17) to 10(20) cm(-3) grown by metal-organic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE) were investigated by variable-temperature photoluminescence and absorption measurements. The energy positions of absorption edge as well as photoluminescence peak of these InN samples with electron concentration above 10(18) cm(-3) show a distinct S-shape temperature dependence. With a model of potential fluctuations caused by electron-impurity interactions, the behavior can be quantitatively explained in terms of exciton freeze-out in local potential minima at sufficiently low temperatures, followed by thermal redistribution of the localized excitons when the band gap shrinks with increasing temperature. The exciton localization energy sigma (loc) is found to follow the n (5/12) power relation, which testifies to the observed strong localization effects in InN with high electron concentrations.

Heteroepitaxial Growth of 3C-SiC Films on Maskless Patterned Silicon Substrates

Heteroepitaxial growth of 3C-SiC on patterned Si substrates by low pressure chemical vapor deposition (LPCVD) has been investigated to improve the crystal quality of 3C-SiC films. Si substrates were patterned with parallel lines, 1 to 10μm wide and spaced 1 to 10μm apart, which was carried out by photolithography and reactive ion etching. Growth behavior on the patterned substrates was systematically studied by scanning electron microscopy (SEM). An air gap structure and a spherical shape were formed on the patterned Si substrates with different dimensions. The air gap formed after coalescence reduced the stress in the 3C-SiC films, solving the wafer warp and making it possible to grow thicker films. XRD patterns indicated that the films grown on the maskless patterned Si substrates were mainly composed of crystal planes with (111) orientation.

镇海棘螈和大凉疣螈年龄结构研究

通过趾骨切片可以准确鉴定年龄，了解一个物种的最长寿命，也为我们研究确定一个物种的生长特点、性成熟期,以及一个地区一个物种的年龄结构、种群生态(Marnell，1998)和群落生态提供重要信息(Morrison，et a1.，2004)。 本论文使用骨骼鉴龄法对中国浙江省宁波市北仑瑞岩寺林场的镇海棘螈（Echinotriton chinhaiensis）雌性繁群进行了年龄结构研究。结果显示：第一次参加繁殖的年龄为3龄；繁群中数量占优势的是5龄、6龄。而在6龄以后参加繁殖的雌性个体数便开始随着年龄的增大而逐渐减少。参加繁殖的雌性年龄最大个体为8龄。平均年龄为5.13龄。同时对其年龄和头体长、体全长的相关性检验,发现其年龄与头体长和体全长不相关,镇海棘螈雌性的生长方式表现为性成熟后能量主要用于繁殖。 另外,对李子坪大凉疣螈(Tylototriton taliangensis) 雄性繁群进行了年龄结构研究。结果显示：大凉疣螈雄性第一次参加繁殖的年龄为4龄；繁群中数量占优势的是5龄、6龄、7龄。而在7龄以后参加繁殖的雄性个体数便开始随着年龄的增大而逐渐减少。参加繁殖的雄性中年龄最大的个体为10龄。平均年龄为6.7龄。对其年龄和头体长、体全长的相关性检验,发现其年龄与头体长和体全长不相关,大凉疣螈雄性生长特点也表现为性成熟后生长缓慢的特点。 研究材料方面，本文采用野外采样与标本馆标本相结合的方式获得了中国蝾螈科2个重要保护物种繁殖群体的剪（指）趾材料，使得建立于其上的年龄结构工作更加可靠、更加具有代表性。 此外,本论文讨论了镇海棘螈瑞岩寺种群繁殖总量年度间的差异及其产生原因。将1998、1999、2000、2008、2009年镇海棘螈（Echinotriton chinhaiensis） 瑞岩寺种群的繁殖量进行比较，发现虽然雌性平均窝卵数比较稳定，但繁殖总量小于1998、1999、2000年任何一年总产卵量的50%。对2008年镇海棘螈繁殖量大幅下降的原因分析发现, 2007年9、10月影响严重台风的两次强台风、瑞岩寺景区开发等因素可能是造成近年该种群繁殖量大幅下降的原因。而2008年初50年不遇的低温是否影响镇海棘螈的繁殖值得进一步追踪研究。2009年繁殖量较2008年没有明显的增长，可能是由于2007年的台风影响了其繁殖营养的积累。台风的影响可能存在滞后现象,对此有待进一步监测证明。 本研究首次对中国蝾螈科物种进行的年龄结构鉴定，为进一步了解中国蝾螈科动物的种群生态打下了坚实的基础。 Using skeletochronology, we can know the life span of a species, age of reaching sexual mature, and of course age structure, which are vital(Morrison，et a1.，2004). Skeletochronology was performed on Echinotriton chinhaiensis Ruiyansi female population. The result shows that: The oldest individuals were 8 years old and the youngest ones were 3 years old. Individuals of age class 5(39.13%) and 6(21.74%) were most numerous. The number of individuals participated in reproduction decreased with the increase of age after the sixth year. Average age is 5.13 years. There is no correlation between age and body size (SVL and TL). For female chinhai salamander, energy is devoted to reproduction after reaching sexual maturation. While using skeletochronology to study Tylototriton taliangensis Liziping male population, the oldest individuals is 10 years old, and the youngest ones is 4 years old. Individuals of the age class 5, 6, and 7 dominat this population. The number of individuals decrease with the increase of age also after the seventh year. Average age is 6.7 years old in this population. there is also no correlation between age and body size (SVL and TL).It turned out that T. taliangensis tend to grow slowly after reaching sexual maturation. In this thesis, specimens from both wild and museum were used to gain enough toe clipping samples. A big sample size guarantees the reliability of this study. In the meantime, E. chinhaiensis’s annual reproduction of the year 1998, 1999, 2000 ,2008,and 2009 was compared. The result shows there is a huge decline in E. chinhaiensis’s annual reproduction in 2008,even the egg clutch is very stable. After analyzing, it turned out the huge decline in 2008 was probably caused by typhoon in 2007, besides the effect of tourism development and cash crop planting. While the impact of extreme weather of 2008 on reproduction needs further investigation. In the year 2009, there is no obvious increase in annual reproduction. It maybe due to lasting impact of typhoon in 2007. It is the first age-structure study on these two Chinese salamanders. A solid foundation was laid for further population ecology study of these two species.

一种新奇的甲烷氧化细菌——能兼性营养和厌氧生长的沼气甲基弯菌

经过细心的条件选择实现了无甲烷条件下甲烷氧化菌沼气甲基弯菌81Z(methylosinus methanica 81Z)利用C2化合物的生长，同时 发现二碳代谢中间产物甘氨酸的胞外积累及对生长的抑制作用。又在此基础上从81Z原种中富集得到一株菌81Z-A，兼性生长能力大 幅度提高，而且除乙酸外又能利用丙酮酸、苹果酸、柠檬酸、葡萄糖而生长。对细胞氧化各种有机底物时氧吸收的测定及酶分析结 果发现了在其它甲烷氧化细菌中未曾发现的异柠檬酸裂解酶和苹果酸酶的存在，表明81Z除了具有通常II型菌的碳代谢途径外，具 有特殊的补偿代谢途径——乙醛酸支路以及从乙酸生糖的回补途径。因此推证其兼性生长的能力是固有的，从而说明了甲烷氧化菌 的专一性概念没有普遍意义。说明了81Z还能在含有二碳的培养基中厌氧生长，包括细胞的分裂和增值行为。虽然这种厌氧生长还 很弱，但至少可以说明它不是严格好氧的，这对于传统的关于甲烷氧化菌的严格好氧的概念是一个冲击。81Z正常条件下是利用甲 烷而生长的，当供给它乙酸、乙醛酸和丝氨酸时能促进含C-C键有机物氧化的活性，而对甲烷单加氧酶和其它C2化合物的氧化有抑 制或阻遏作用，对碳同化的丝氨酸途径的关键酶羟基丙酮酸还原酶有阻抑作用。同时也证明了81Z的甲烷单加氧酶和甲醇氧化活性 可被甲烷、甲醇所诱导，而因甲酸而降低。The growth of Methylosinus methanica 81Z on C2-compounds without methane was realized by selecting suitable conditions. The intermediate product Gly from its C2 metabolism was found to accumulate out cells and inhibit its growth. 81Z-A, which was obtained from 81Z by richening, could grow on C2- compounds rapidly. It can even grow on pyruvate, malate, citrate and glucose. The results of measurements of oxygen consumption by cell suspensions in the presence of various organic compounds and the results of enzyme assays of detected activities of isocitrate lyaze and malic enzyme in cell extracts which were not found in other methantrophs showed that 81Z possesses not only the regular carbon metabalic pathways but also some peculiar anaplerotic pathways--the glyoxylate cycle and the gluconeogenic pathway from acetate. As a consequence of these studies, its ability of facultative growth is inherent. Therefore, the concept of obligate dependence on C2- compounds of methanotrophs is not of universal significance. The ability of 81Z's growth(including desintegration and proliferation behaviour) on C2-compounds anaerobically was also demonstrated. Despite of the weakness of this growth, at least it could be said that 81Z is not strictly aerobic. This is a strike to the traditonal concept about the strictly aerobic action of methanotrophs. Regularly, 81Z grows on methane. The presence of acetate, glyoxylate and serine could increaze its ability of oxidizing the organic coumpounds containing C-C ponds. In contrast, they could inhibit the activities of MMO and other C2-compounds oxidation, they also repressed the key enzyme hydroxypyruvate reductase of the serine-pathway for carbon assimilation. At the some time, it was testified that the activities of MMO and methanol oxidation were inducible by methane or methanol and were lower in the presence of formate.

The neutron/proton ratio of squeezed-out nucleons and the high density behavior of the nuclear symmetry energy

Within a transport model it is shown that the neutron/proton ratio of squeezed-out nucleons perpendicular to the reaction plane, especially at high transverse momenta, in heavy-ion reactions induced by high energy neutron-rich nuclei can be a useful tool for studying the high density behavior of the nuclear symmetry energy.

Cultivation of the brown alga Sargassum horneri: sexual reproduction and seedling production in tank culture under reduced solar irradiance in ambient temperature

As a large conspicuous intertidal brown alga, individuals of Sargassum horneri can reach a length of more than 7 m with a fresh weight of 3 kg along the coasts of the Eastern China Sea. The biomass of this alga as a vital component in coastal water ecology has been well documented. In recent years, a steady disappearance of the algal biomass along the once densely populated coastal areas of the Eastern China Sea has drawn attention in China. Efforts have been made to reconstruct the subtidal algal flora or even to grow the alga by use of long-lines. As part of the efforts to establish an efficient technique for producing seedlings of S. horneri, in this investigation a series of culture experiments were carried out in indoor raceway and rectangular tanks under reduced solar irradiance at ambient temperature in 2007-2008. The investigation demonstrated that: (1) sexual reproduction of S. horneri could be accelerated in elevated temperature and light climates, at least 3 months earlier than in the wild; (2) eggs of S. horneri had the potential to be fertilized up to 48 h, much longer than that of known related species; (3) suspension and fixed culture methods were both effective in growing the seedlings to the long-line cultivation stage; and (4) the life cycle of S. horneri in culture could be shortened to 4.5 months, thus establishing this alga as an appropriate model for investigating sexual reproduction in dieocious species of this genus.

Studies on hybridization effects of different geographic populations of Chlamys farreri - II. The medium-term growth and development of Chlamys farreri populations from China and Russia and their reciprocal crosses

Based on the research of juvenile (2, 3, 4 months) growth and survival of three populations of two different geographic areas in Chlamys farreri from Russian and China and their F, hybrids derived from Chinese cultural population (CC) female x Russian population (RW) male, Chinese wild population (CW) female x Russian population (RW) male, Russian population (RW) female x Chinese wild population (CW) the study of the medium-term (6, 8, 10, 12 months) growth and development of Chlamys farreri was carried out. The four determined results indicated that there existed different extent heterosis (3% similar to 52 %) for the growth in three types of F-1 hybrids, and the offspring derived from CC female X Rmale had a stronger heterosis among the crosses at the medium-term; the uptrend among traits are wet weight > shell width > shell length > shell height, Chinese cultural population could be recognized as excellent parent, and seasonal variations influence very much on the daily increment and growth rate of each trait of Chlamys farreri and it is only able to survive and could barely grow in winter (6 similar to 8 months), but grows fast in temperate season (10similar to12 months).

评价水产动物生长性能的生理生化指标和分子生物学指标

以奥利亚罗非鱼(Oreochromis aureus)为实验对象，设计了3种不同的摄食类型，分别是鲜活饵料组、饥饿3周后饱食投喂组和人工饲料组。鲜活饵料组投喂冰冻赤子爱胜蚓，利用蚯蚓体内丰富的营养成分和活性物质，以期获得奥利亚罗非鱼良好的生长状况；饥饿后饱食组是指饥饿3周后，以人工饲料饱食投喂2周，用于研究饥饿与补偿生长获得快速生长时血液理化指标的变化情况；人工饲料组作为对照组。纯淡水条件下养殖，水温25±2℃。测定了奥利亚罗非鱼在3种摄食类型饲喂下某些血液生理生化指标变化的情况，并将指标变化情况与增重率做相关性分析，试图找出能够反映奥利亚罗非鱼生长性能的血液生理生化指标。 研究结果表明，奥利亚罗非鱼在饥饿3周后获得了补偿生长，补偿生长时的增重率和特定生长率显著高于人工饲料组(P<0.05)，高于鲜活饵料组，但差别不显著；相关性分析研究表明血清总蛋白、胆固醇、四碘甲状腺原氨酸（T4）与增重率极显著相关(P<0.01)，血红蛋白显著相关(P<0.05)，红细胞、白细胞、碱性磷酸酶高度相关(相关系数为0.580、0.551和0.557)，因此，建议血清总蛋白、胆固醇和血红蛋白可作为能够反映罗非鱼生长性能的新指标。 根据序列设计引物，PCR反应条件：变性温度：95 ℃，3 min；退火温度：57℃，20 sec；延伸温度：72℃，5 min，共36个循环，从牙鲆、黑鲪和鲈鱼中克隆出胰岛素样生长因子（IGF-Ⅰ）部分序列，首次证实了IGF-Ⅰ在3种海水鱼中的存在。 利用蛋氨酸与ZnSO4•7H2O，在pH 5.5、80℃下，反应1小时，采用蛋氨酸与硫酸锌2：1的配料比，合成出了产物蛋氨酸螯合锌，蛋氨酸螯合锌外观白色，粉状，室温下微溶于水，不溶于乙醇，并用原子吸收光谱法测定其含锌量为15%，螯合率为88.2%。