Study of Optical Characteristics of InGaN/GaN MQW LED Depended on Growth Temperature

利用低压MOCVD系统,在蓝宝石衬底上外延生长了InGaN/GaN多量子阱蓝紫光LED结构材料。研究了生长温度对有源层InGaN/GaN多量子阱的合金组分、结晶品质及其发光特性的影响。结果表明当生长温度从730℃升到800℃时,LED的光致发光波长从490 nm移到380 nm,室温下PL谱发光峰的半高全宽从133 meV降到73 meV,表明了量子阱结晶性的提高。高温生长时,PL谱中还观察到了GaN的蓝带发光峰,说明量子阱对载流子的限制作用有所减弱。研究表明,通过改变生长温度可以对LED发光波长及有源层InGaN的晶体质量实现良好的控制。A series of blue-violet LEDs with InGaN/GaN multi-quantum-wells(MQWs) structure were grown by low-pressure metalorganic chemical vapor deposition(LP-MOCVD).The growth temperature of the active layer is very important for the indium concentration,crystal quality and optical properties of the sample.The emission wavelength over the range of 490~380 nm were achieved by varying the growth temperature between 730 ℃ and 800 ℃.And the full width at half of maximum of the photoluminescence and electricaluminescence spectrum were studied as a function(FWHM) of the growth temperature.Analysis of the relation between the emission spectrum and the growth temperature indicated that the high crystal quality and the expected emission wavelength can be achieved by controling the growth temperature of the active layer.国家自然科学基金项目(60276029);; 国家“863”计划项目(2004AA311020,2006AA032409);; 福建省科技项目(2006H0092,A0210006,2005HZ1018

Total Amount Control of Air Pollutant in Building Industrial Area

该文论述了在工业区建设环境管理中实施大气污染物总量控制的必要性,阐述了区域实施大气污染物总量控制的基本条件,提出在工业区建设环境管理中实施大气污染物总量控制的步骤和方法。The paper points out it is necessary that total amount control of air pollutant should be implemented in build ing industrial area.sets forth its basic conditions ,then puts forward its steps and methods

Pollution Characteristics and Ecological Risk of PBDEs in Water and Sediment from an Electronic Waste Dismantling Area in Taizhou

以台州某电子垃圾拆解工业园为圆心,在半径为16 km的范围内,由近及远设计了C(3 km)、S(5~10 km)和R(10~16km)三圈共30个采样点,研究了该区域水及沉积物中多溴联苯醚(PBDEs)的污染特征与生态风险.结果表明,水中PBDEs含量为9.4~57.2 ng·L~(-1),平均值为25.9 ng·L~(-1);沉积物中PBDEs含量为3.7~38 775 ng·g~(-1),平均值为2 779 ng·g~(-1);BDE-209均为主要成分.水及沉积物中PBDEs含量的空间分布态势均为:C圈>S圈>R圈,沉积物中PBDEs含量和离工业园区中心的距离呈极显著负相关(P S > R. Furthermore,the concentrations of PBDEs in sediments showed significant negative correlation against the distance from the industrial park( P < 0. 01). Compared with other regions around the world,the PBDEs contamination was more serious in the area,which indicated that e-waste dismantling activity was one of the significant sources for PBDEs pollution. It was estimated that a total of 30. 7 t PBDEs( including 28. 9 t BDE-209) was discharged into surrounding environment as a result of dismantling industrial activities in last 40 years. A preliminary ecological risk assessment for PBDEs in water and sediments was conducted by hazard quotient method. The results demonstrated that the Penta-BDEs in the center of e-waste dismantling area( a radius of 1. 5 km) was at particularly high risk level and could cause serious influence on the ecological safety and human health.环境保护公益性行业科研专项(201309047

Development on AlInGaN/GaN PIN Ultraviolet Photodetectors

用AlInGaN四元合金代替AlGaN作为PIN探测器的有源层,研制出AlInGaNPIN紫外探测器。详细介绍了该器件的结构设计和制作工艺,并对器件进行了光电性能测试。测试结果表明,器件的正向开启电压约为1.5 V,反向击穿电压大于40 V;室温-5 V偏压下,暗电流为33 pA,350 nm处峰值响应度为0.163 A/W,量子效率为58%。Using AlInGaN instead of AlGaN as the source film of a photodetectors,an AlInGaN-based PIN UV photodetector was developed.Its device structure and fabrication processing are introduced in detail.Measurement results show that its turn-on voltage is about 1.5 V,and VBR>40 V;under-5 V bias voltage at room temperature,the dark current is about 33 pA;the peak responsivity can reach 0.163 A/ W at 350 nm,and the quantum efficiency is 58%.国家自然科学基金项目(60276029);; 国家“863”计划项目(2004AA311020,2006AA032409);; 福建省科技项目和基金项目(2006H0092,A0210006,2005HZ1018

Optimization Electrode of GaN-Based Light-Emitting Diode

针对以蓝宝石为衬底的GaN基发光二极管出现的电流扩展不均的问题,采用有限元方法建立了GaN基发光二极管的三维网络模型,并对四种常见结构的器件进行数值模拟,发现影响二极管电流的因素不仅与发光二极管电极的位置有关,而且依赖于器件的结构参数。以电流扩展不均为指标确定出这四种器件中最佳的电极位置分布,同时对最佳电极位置分布的器件进行了结构参数优化,结果表明当p型金属层方块电阻与n型GaN的方块电阻接近时,电流扩展均匀性最好,且p-GaN的接触电阻和厚度越小,电流扩展越不均匀。A 3D networks model of GaN-based LED on sapphire substrate was built by finite element analysis to simulate the non-uniformity current spreading.Analog modeling was done on the four normal device structures,it was found that the factors effected the current of LED were the position of electrode and the parameters of device structure.Considering the practical structures of GaN-based LED,four LED designs were modeled and the optimal electrode distribution was obtained,meanwhile the structure parameters were optimized.It reveals that the smaller contact resistances and the thickness of p-GaN are,the more non-uniformity of current distribution is.国家自然科学基金(60276029);; 国家863计划(2004AA311020和2006AA032409);; 福建省科技项目和基金(2006H0092,A0210006,2005HZ1018

脱氧胆酸改性普鲁兰多糖纳米粒子制备与表征

通过酯化反应将脱氧胆酸偶联于普鲁兰多糖骨架形成具有两亲性的普鲁兰多糖衍生物(DP),采用纳米沉淀法制备纳米粒子(DPNs),考察制备条件对纳米粒子性质影响,为进一步将其作为药物载体的研究提供基础。衍生物DP结构通过FT-IR和1 H NMR表征,DPNs经透射电镜、动态光散射仪和zeta电位仪表征检测。获得不同取代度脱氧胆酸改性普鲁兰多糖衍生物,制备得到的纳米粒子呈球形,表面光滑规整,平均粒径100～300nm,zeta电位在-20mV左右。脱氧胆酸改性普鲁兰多糖衍生物通过纳米沉淀法能制备出纳米粒子,颗粒性质受制备条件影响

基于DEA模型分析我国公立医院运行效率

目的运用数据包络分析方法评价我国公立医院运行效率及变化,为公立医院提高运行效率、进一步完善和优化卫生资源配置提供决策依据。方法选取2011-2015年《中国卫生统计年鉴》等统计资料中的数据,采用数据包络分析法的CCR模型在规模报酬不变情况下计算综合效率值、BCC模型在规模报酬可变情况下计算纯技术效率值和规模效率值,对全国公立医院的运行效率进行分析,并通过Malmquist模型对生产效率变化趋势进行分析。结果 2014年全国31个省市公立医院平均综合效率值为0.887,综合效率值为1即DEA有效的省市10个,处于规模效率不变状态,其他省市是DEA非有效且处于规模效率递减状态;DEA有效省市主要集中在东部和西部;26个(83.88%)省市公立医院全要素生产率提高;非DEA有效省市若达到DEA有效可节省大量卫生资源投入、获得更多医院产出。结论近五年我国公立医院管理和技术方面效率有很大提高,但由于医院规模扩张过快反而降低了医院运行效率。适度的规模更有利于公立医院效率的提高,应该控制大型公立医院的发展规模,引导医院提高医疗技术和管理水平,促进内涵式发展,改善服务、改进管理,从而提高效率。国家自然科学基金项目(71403229

Engineering practice of the treatment of wastewater from flexible printed circuit board factories

介绍了厦门某电子科技有限公司废水处理工程实例。针对该线路板厂废水来源的不同,依据分类收集、先预处理再综合处理的原则对废水进行合理的细化分类,对不同的水质进行不同的物化处理。工程试车结果表明,采用本工艺路线处理后的柔性印制电路板废水出水水质达到或优于GB8978—1996一级排放标准。An example of the engineering practice of the wastewater treatment at an electronic technology company in Xiamen is introduced. Considering the different characteristics of wastewater sources at the circuit board factory, and based on classifying the collections, the principle of classifying the wastewater is followed and the wastewater is treated properly and detailedly by pre-treatment firstly and then by comprehensive treatment. Wastewater with different water quality is treated by different physicochemical treatment. The practice results show that when flexible printed circuit board wastewater is treated by this process,the effluent water quality meets or superior to the requirement of the first class of the standard,GB 8978—1996

前列腺移行带腺体定量分析

目的通过定量分析良性前列腺增生(BPH)患者前列腺和成人正常前列腺移行带腺体各成分含量及相关组织学形态的变化,探讨良性前列腺增生症治疗方案的选择。方法用计算机图像分析系统对经HE染色的40例良性前列腺增生症患者手术切除的前列腺和10例成人正常前列腺移行带组织标本进行形态学定量分析,分别测定腺体、腺腔、上皮的平均面积及上皮细胞高度。结果(1)正常前列腺和BPH前列腺移行带上皮细胞高度分别为(24.87±4.53)μm和(19.06±5.49)μm(P0.05)。结论BPH前列腺组织主要以基质成分增生为主;BPH的治疗应以α受体阻滞剂和手术治疗为主