离子注入掺铒硅发光中心的光致发光研究

详细地分析了离子注入掺铒硅的光致发光谱，有5个发光峰分别位于1.536μm、1.554μ、1.570μm、1.598μ和1.640μm,其中1.536μm发光峰最强。结合背散射谱，认为其有效的发光中心为处于T_d对称中心的填隙铒Er~(3+)离子。在Er与O、N、C共掺样品应分别存在Er-O、Er-N和Er-C发光中心，其对应的PL发光峰分别为1.570μm、1.536μm和1.608μm。

GaAs/Ga（0.7）Al（0.3）As短周期超晶格中的自电光双稳和多稳态效应

国家自然科学基金

MMI optical couplers and switches with SOI technology

MMI (multimode interference) coupler, modulator and switch based on SOI (silicon- on-insulator) have been become more and more attractive in optical systems since they show important performances. SiO2 thin cladding layers (<1.0mum) can be used in SOI waveguide due to the large index step between Si and SiO2, making them compatible with the VLSI technology. The design and fabrication of multimode interference (MMI) optical coupler, modulator and switche in SOI technology are presented in the paper. The results demonstrated that the modulator has an extinction ratio of -11.0dB and excess loss of -2.5dB, while the optical switch has a crosstalk of -12.5dB and responding time of less than 20 mus.

The role of hydrogen in semi-insulating INP

Complexes of vacancy at indium site with one to four hydrogen atoms and isolated hydrogen or hydrogen dimer and other infrared absorption lines, tentatively be assigned to hydrogen related defects were investigated by FTIR. Hydrogen cam passivate imperfections, thereby eliminating detrimental electronic states from the energy bandgap. Incorporated hydrogen can introduce extended defects and generate electrically-active defects. Hydrogen also can acts as an actuator for creating of antistructure defects. Isolated hydrogen related defects(e.. H-2*) may play an important role in the conversion of the annealed wafers from semiconducting to the semi-insulating behavior. H-2* may be a deep donor, whose energy level is very near the iron deep acceptor level in the energy gap.

Proof of InAs/GaAs self-organized quantum dot lasing and the experimental determination of local Strain effect on the band structures

Confirmation of quantum dot lasing have been given by photoluminescence and electro-luminescence spectra. Energy levels of QD laser are distinctively resolved due to band filling effect, and the lasing energy of quantum dot laser is much lower than quantum well laser. The energy barrier at InAs/GaAs interface due to the built-in strain in self-organized system has been determined experimentally by deep level transient spectroscopy (DLTS). Such barrier has been predicted by previous theories and can be explained by the apexes appeared in the interface between InAs and GaAs caused by strain.

日本落叶松微体繁殖及植株再生的研究

本文以10、13、29年生的日本落叶松(Laxix kaempferi (Lamb.)Carr.) 朝85；38、朝6号无性系的冬芽为材料，经过腑芽诱导、不定茎伸长、生根诱导和培养等阶段，形成了再生植株。文中主要研究了基本培养基种类、激素组合及其浓度、遗传材料（无性系）、外植体年龄、活性炭对芽诱导、茎伸长以及继代、温度、染菌等对植株再生过程的影响。通过实验，选择出微体繁殖过程中茎诱导、茎伸长、生根诱导等各个阶段的优化培养基，它们分别是：茎诱导SH+0.5mg/l Zea+0.05mg/l IAA WPM+1mg/l zea+1mg/l IAA；茎伸长 改良MS+0.1mg/l IBA+0.5mg/l NAA+1% AC; 根诱导 改良MS+0.2mg/l IBA+0.1mg/l NAA+0.15% AC。培养条件诱导、伸长时光照1000－3000Lux，温度 25±1℃；生根时光照不变，温度 20±1℃。对影响外植体发育和器官发生各种因素的研究结果表明：继代可明显提高诱导率，继代、低温处理相结合促进生根；高浓度（1%）活性炭对茎伸长有明显的促进作用，低浓度（0.15）活性炭则促进根的形成；诱导率也随年龄、无性系的变化而不同；在根诱导阶段，细感染并不影响生根。同时，文中还对无菌幼苗的扦插进行了实验，以为成龄树木棰根提供可借鉴的资料。

东北农田生态系统排放CH_4和N_2O的研究

本文首次对我国东北地区稻田和旱田（大豆田）中甲烷（CH_4）和氧化亚氮(N_2O)的排放通量进行观测,研究了环境因素对这两种温室效应气体排放的影响。观测结果表明：稻田在作物生长季节是CH_4的排放源(source)，作物被收割之后则成为甲烷的汇(sink)。在作物生长季，稻田的CH_4排放通量变化在2.41-26.1mgCH_4/m~2·h之间，平均通量为14.82mgCH_4/m~2·h。稻田N_2O通量在-116.89-100.69μgN_2O/m~2·h间变化，平均通量为-6.36 μg/m~2·h。旱田完全是N_2O的排放源，通量在3.99-332.3 μg N_2O/m~2·h之间变化，平均通量是88.54 μgN_2O/m~2·h。旱田主要表现为甲烷的汇。稻田中甲烷主要在0-5cm土层中产生。水稻和大豆分别对CH_4和N_2O的排放起着重要作用。稻田甲烷排放通量与温度(特别是气温)有极显著的正相关性，也与土壤中硝态氮含量呈显著正相关／旱田甲烷排放通量与土壤中铵态氮浓度呈显著负相关，而N_2O通量则与铵态氮浓度呈正相关，但有3-4天的时间滞后现象。旱田甲烷和氧化亚氮的排放受土壤含水量的影响。本文还讨论了实验室条件下施肥对稻田土壤CH_4产生作用的影响。厩肥的施入影响较弱，而稻杆的影响则十分强烈。尿素也促进CH_4的产生。100和200μg/g(土)的尿素加入量增大了产甲烷速率和甲烷产量；300μg/g(土)的尿素加入量没有增大产甲烷速率，却延长产甲烷时间，使甲烷产量增加更多。土壤中CH_4和N_2O的产生过程之间似乎呈相互消长关系。