Fabrication and Characteristics of GaN-based Blue VCSEL

利用金属有机物气相沉积技术(MOCVD)在(0001)蓝宝石衬底上生长了Ga N基垂直腔面发射激光器(VCSEL)的多量子阱腔层结构。X射线衍射测量显示该多量子阱具有良好周期结构和平整界面。运用键合及激光剥离技术将该外延片制作成VCSEL,顶部和底部反射镜为极高反射率的介质膜分布布拉格反射镜(DBR)。在室温、紫外脉冲激光的泵浦条件下,观察到了VCSEL明显的激射现象,峰值波长位于447.7 nm,半高宽为0.11 nm,自发辐射因子约为6.0×10-2,阈值能量密度约为8.8 m J/cm2。在大幅度降低制作难度的情况下,得到目前国际最好结果同样数量级的激射阈值。降低器件制作难度有利于制备的重复性,有利于器件的产品化。Ga N-based multiple quantum wells( MQWs) were epitaxially grown on( 0001)-oriented sapphire substrate by metal organic chemical vapor deposition( MOCVD) technique. X-ray diffraction measurements indicated that the MQWs had good periodic structure and smooth interface. By employing bonding and laser lift-off techniques,the MQW structure was sandwiched between two high reflectivity dielectric distributed Bragg reflectors( DBRs),forming a vertical-cavity surfaceemitting laser( VCSEL). Under optical pumping,the VCSEL achieved laser action at room temperature with a threshold pumping energy density of about 8. 8 m J / cm2. The laser emitted a blue light at 447. 7 nm with a narrow linewidth of 0. 11 nm,and had a high spontaneous emission factor of about 6. 0 × 10- 2.国家自然科学基金(61307115);; 福建省教育厅A类科技项目(JA12249);; 厦门理工学院高校高层次人才基金(YKJ11026R);; 福建省自然科学基金(2013J05104)资助项

Polishing of Laser Lift-off-Induced GaN Surface

激光剥离(llO)技术是研制新型氮化镓(gAn)基谐振腔结构光电子器件的关键技术。然而llO后的gAn表面往往具有较大的粗糙度,而制作谐振腔结构器件需要很高的表面平整度,因此需要对llO后的gAn表面进行抛光。分别采用金刚石粉抛光液和胶粒二氧化硅抛光液进行机械抛光和化学机械抛光(CMP),并对比了两种方法获得的抛光结果,研究发现前者会在抛光后的gAn表面引入划痕,而采用后者可以得到亚纳米级平整度的表面。进一步的实验结果表明,胶粒二氧化硅抛光液同样适用于图形化衬底外延片激光剥离后的gAn表面抛光。Laser lift-off( LLO) is a key technology in development of new GaN-based resonant-cavity optoelectronic devices.For cavity-dependent devices,a smooth surface is highly required.However,the GaN surface after LLO is usually rough,and the polishing is necessary.The mechanical polishing of diamond powder and the chemical mechanical polishing of colloidal silica were compared.It is found that diamond powder leads to scratches on the GaN surface whereas colloidal silica leads to smooth surface with sub-nanometer roughness.The experiment results indicate that polishing with colloidal silica solutions can be applied to smoothen the LLO-produced GaN surface from an epitaxial wafer grown on patterned-sapphire substrate.国家自然科学基金资助项目(61274052;61106044); 中国科学院纳米器件与应用重点实验室开放课题资助项目(14ZS02

一种高效、稳定的分泌型原核表达载体的构建及应用

以本室构建的原核表达载体pTO-T7为基础载体,PCR合成ompT引导序列,插入该载体多克隆位点上游,构建了分泌型原核表达载体pTO-OT。将2个外源基因克隆至pTO-OT,2个重组质粒在大肠杆菌中均得以高效表达,表达产量在25％～34％之间。Western blot分析证实了融合蛋白可被大肠杆菌信号肽酶有效地切割,并具有良好的免疫学活性。对重组表达菌株的连续传代实验证实了该表达载体具有良好的表达稳定性,显示了其在基因工程中的应用价值

一种高效、稳定的分泌型原核表达载体的构建及应用

以本室构建的原核表达载体pTO-T7为基础载体,PCR合成ompT引导序列,插入该载体多克隆位点上游,构建了分泌型原核表达载体pTO-OT。将2个外源基因克隆至pTO-OT,2个重组质粒在大肠杆菌中均得以高效表达,表达量为25％-30％。Western印迹分析证实了重组蛋白在大肠杆菌中表达后可被信号肽酶有效识别,切割后的重组蛋白具有良好的免疫学活性。对重组表达菌株的连续传代实验证实了该表达载体具有良好的遗传稳定性,显示了该原核表达载体在基因工程中的应用价值

水蒸气改性H-FER分子筛在催化丁烯异构化反应中的应用

为了进一步提高FER分子筛的催化性能及稳定性,以水蒸气对H-FER分子筛进行改性处理。结果表明,水蒸气处理可以有效调变对H-FER分子筛孔结构和酸性,且保持其晶型相对完整。在水蒸气流量和处理温度分别为1.0 mL/min和370℃下,处理30 min后的H-FER具有最佳的催化性能。X射线衍射和氮气吸脱附等表征结果表明,较高的水蒸气处理温度（370～420℃）和较大的水蒸气流量（1～3 mL/min）可同时调控微孔和介孔的结构。另一方面,介孔与微孔的合理匹配对H-FER催化剂的稳定性影响处于主要地位,酸性变化的影响则处于次要地位。而且,对于丁烯、异丁烯等反应物/产物,H-FER分子筛的微孔孔径不宜过大（<1.45 nm）,dmicro/dmeso也不应大于0.19,即微介孔的连通性相当重要。中央高校基本科研业务费专项(20720170029

Effects of Moxibustion on Gastric Stress Ulcer Rats' Apoptosis Protein Phosphorylation

目的:研究艾灸对应激性胃溃疡大鼠胃黏膜细胞凋亡蛋白质磷酸化的影响,探讨艾灸促进胃黏膜损伤修复的信号转导机制。方法:将大鼠随机分为正常组、模型组、胃经穴组和对照点组,采用束缚冷应激法制作应激性胃溃疡大鼠模型,肉眼观察大鼠胃黏膜损伤程度,APOPTOSIS MICrOArrAy SlIdES芯片检测胃黏膜细胞凋亡蛋白质磷酸化水平。结果:与模型组比较,胃经穴组和对照点组大鼠胃黏膜损伤指数值均显著降低(P<0.05);与对照点组比较,胃经穴组大鼠胃黏膜损伤指数显著降低(P<0.05);APOPTOSIS MICrOArrAy SlIdES芯片检测结果显示:与模型组比较,胃经穴组大鼠胃黏膜细胞10种蛋白质磷酸化水平上调,其中bCl-Xl、MCl-1、bCl-2、IAPS 4种蛋白磷酸化水平差异有统计学意义(P<0.01,P<0.05);18种蛋白质磷酸化水平下调,其中Tnf、fAS、APAf-1、CASPASE-3、CASPASE-9、bAX 6种蛋白质磷酸化水平差异有统计学意义(P<0.01,P<0.05)。结论:艾灸可促进胃黏膜的损伤修复,调节多种凋亡相关信号蛋白质的磷酸化水平,并且存在一定的经脉脏腑相关性。Objective: To study the effects of moxibustion on apoptosis protein phosphorylation in rats with gastric stress ulcer and to explore the signal transduction mechanisms promoting gastric mucosal injury and repairing moxibustion.Methods: The rats were randomly divided into normal group,model group,stomach meridian group and the control point groups and each group had 10 rats.The stress ulcer rat model was established by using restraint cold stress method.We observed the rat gastric mucosa injury degree and Apoptosis Microarray Slides microarray was used to observe the gastric apoptosis protein phosphorylation levels.Results: Compared with the model group,the gastric mucosa injury index values of control point and meridian groups were significantly lower( P < 0.05).Compared with the control point group,a significant reduction in rat gastric mucosa injury index was in meridian group( P < 0.05).Apoptosis Microarray Slides microarray results showed that 10 kinds of protein phosphorylation levels increased,among which Bcl- XL,Mcl- 1,Bcl-2 and IAPs protein phosphorylation levels were statistically significant( P < 0.01,P < 0.05) and 18 kinds of protein phosphorylation levels decreased,among which TNF,Fas,Apaf- 1,Caspase- 3,Caspase- 9 and Bax protein phosphorylation levels were statistically significant( P < 0.01,P < 0.05).Conclusion: Moxibustion can promote gastric mucosal injury and repair and regulate phosphorylation of several proteins related to apoptotic signals and there is a certain correlation between the meridians organs.国家自然科学基金项目(30960484;81260556

The exciton-longitudinal-optical-phonon coupling in InGaN/GaN single quantum wells with various cap layer thicknesses

This paper studies the exciton-longitudinal-optical-phonon coupling in InGaN/GaN single quantum wells with various cap layer thicknesses by low temperature photoluminescence (PL) measurements With increasing cap layer thickness, the PL peak energy shifts to lower energy and the coupling strength between the exciton and longitudinal-optical (LO) phonon, described by Huang-Rhys factor, increases remarkably due to an enhancement of the internal electric field With increasing excitation intensity, the zero-phonon peak shows a blueshift and the Huang-Rhys factor decreases These results reveal that there is a large built-in electric field in the well layer and the exciton-LO phonon coupling is strongly affected by the thickness of the cap layerNational Natural Science Foundation of China [60876007, 10974165]; Xiamen Municipal Science and Technology Bureau, China [2006AA03Z110

Damage to mangroves from extreme cold in early 2008 in southern China

通讯作者Author for correspondence (E-mail: [email protected])2008年初,我国南方19个省经历了50年一遇的持续低温雨雪冰冻天气。极端气候对华南沿海各省的红树林区造成不同程度的危害。2008年3月,在我国南方各省红树林区的10个代表性地点,对这次寒害造成的红树植物伤害程度进行了系统的调查。结果表明:冬季低温对红树林的影响极为显著,特别是在低纬度的海南、广西和广东湛江,由于极端低温正值夜间退潮,对红树林的影响更为显著;在纬度较高的福建,本地红树种类秋茄(Kandelia obovata)、桐花树(Aegiceras corniculatum)和白骨壤(Avicennia marina)及引种的木榄(Bruguiera gymnorrhiza)等,由于长期适应于冬季较低的气温或在种植前经过抗寒锻炼,具有较强的抗寒能力。各地主要红树植物中,广布种秋茄、桐花树和白骨壤最为耐寒,其耐寒性均大于红树科的木榄、海莲(Bruguiera sexangula)和红海榄(Rhizophora stylosa)。海桑(Sonneratia caseolaris)对温度的敏感性最强,抗寒能力最低,因此,即使在其原产地海南也受到较为严重的寒害,在纬度更高的引种地出现大面积受害甚至全部死亡,而从孟加拉国引种的无瓣海桑(Sonneratia apetala)却显示出一定的抗寒能力。同一地点的红树植物幼苗的抗寒能力低于大树。此次寒害也造成了苗圃场的种苗大量死亡,成熟的植株提前落花落果,这势必会影响后继一两年内红树林的自然更新和人工造林。因此,在未来红树林造林或人工引种中,一定要考虑到红树植物的抗寒能力。国家自然科学基金(30671646和30700092);厦门大学“闽江学者”启动基

河北省产业结构现状的实证分析及对策研究

产业结构的演进与优化直接制约着经济的发展与增长。近年来,伴随着经济的发展,河北省产业结构得到了很大的调整和完善。但从总体上看,产业结构低级化、重复化的问题依旧突出。文章通过对河北省产业结构的现状进行实证分析,分析其内在的不足和问题,在此基础上寻求其产业结构优化调整的战略