生物分子结合水的结构与动力学研究进展

生物结合水在维护生物大分子的结构、稳定性以及调控动力学性质和生理功能等方面起着决定性的作用.从分子水平上理解生物结合水分子的结构与性质及其影响生物结构和功能的本质与规律,是揭示生物大分子生理功能机理的关键.目前生物结合水的结构与动力学相关研究尚处于初步阶段.本文从三个方面介绍当前生物结合水的相关研究及其进展:首先介绍结合水对蛋白质折叠、质子给予与迁移、配体结合与药物设计以及变构效应等生物结构和功能的影响;然后介绍生物分子周围的水分子结构研究情况;最后从时间尺度、动力学属性、生物分子与水分子之间的动力学耦合作用、蛋白质表面结合水次扩散运动等角度介绍生物分子水合动力学的研究进展,并归纳出一些目前尚待进一步解决的科学问题.     

Large-scale SiO2 photonic crystal for high efficiency GaN LEDs by nanospherical-lens lithography

Wafer-scale SiO2 photonic crystal （PhC） patterns （SiO2 air-hole PhC, SiO2-pillar PhC） on indium tin oxide （ITO） layer of GaN-based light-emitting diode （LED） are fabricated via novel nanospherical-lens lithography. Nanoscale polystyrene spheres are self-assembled into a hexagonal closed-packed monolayer array acting as convex lens for expo- sure using conventional lithography instrument. The light output power is enhanced by as great as 40.5% and 61% over those of as-grown LEDs, for SiO2-hole PhC and SiO2-pillar PhC LEDs, respectively. No degradation to LED electrical properties is found due to the fact that SiO2 PhC structures are fabricated on ITO current spreading electrode. For SiO2- pillar PhC LEDs, which have the largest light output power in all LEDs, no dry etching, which would introduce etching damage, was involved. Our method is demonstrated to be a simple, low cost, and high-yield technique for fabricating the PhC LEDs. Furthermore, the finite difference time domain simulation is also performed to further reveal the emission characteristics of LEDs with PhC structures.     

Effects of AlN nucleation layer thickness on crystal quality of AlN grown by plasma-assisted molecular beam epitaxy

In this paper,the effects of thickness of AlN nucleation layer grown at high temperature on AlN epi-layer crystalline quality are investigated.Crack-free AlN samples with various nucleation thicknesses are grown on sapphire substrates by plasma-assisted molecular beam epitaxy.The AlN crystalline quality is analysed by transmission electron microscope and x-ray diffraction (XRD) rocking curves in both (002) and (102) planes.The surface profiles of nucleation layer with different thicknesses after in-situ annealing are also analysed by atomic force microscope.A critical nucleation thickness for realising high quality AlN films is found.When the nucleation thickness is above a certain value,the (102) XRD full width at half maximum (FWHM) of AlN bulk increases with nucleation thickness increasing,whereas the (002) XRD FWHM shows an opposite trend.These phenomena can be attributed to the characteristics of nucleation islands and the evolution of crystal grains during AlN main layer growth.     

分子束外延生长InGaN／A1N量子点的组分研究

报道了分子束外延生长的绿光波段InGaN／A1N量子点材料,并综合考虑InGaN量子点的应变弛豫,以及应力和量子限制斯塔克效应对量子点发光波长的影响,提出了一种结合反射式高能电子衍射原位测量与光致荧光测量确定InGaN量子点组分的方法．     

A Novel Multisection Distributed Feedback Laser with Varied Ridge Width for Self-Pulsation Generation

A novel ridge-waveguide multisection （MS） distributed feedback （DFB） laser, which consists of two identical DFB sections but different ridge widths, is proposed to generate beating-type self-pulsations （SPs）. The spatiotemporal dynamic response of such a multisection DFB laser is calculated based on a large-signal travelling-wave model. Self-pulsating output at about 150GHz is predicted, and evidences for the beating mechanism of the SPs are provided. To the best of our knowledge, this is the first report on SP generated by MS-DFB lasers with varied ridge width. Compared to other alternatives, such devices are much easier to implement and also enjoy the advantages of lower cost and higher design freedom.     

气相色谱－原子发射光谱联用仪测定18种安眠镇静药的元素比例及其在中毒病人全血样品中的应用

采用气相色谱－原子发射光谱联用仪（ＧＣ－ＡＥＤ）测定了１８种安眠镇静药的元素组成和元素比例。根据气相色浴－质谱（ＧＣ－ＭＳ）测定的分子量数据推测出它们的分子式，结果与实际值一致。以元素组成、元素比例和保留时间为判据，对一例中毒患者全血样品进行了定性分析，发现血中含有苯巴比妥。     

光折变晶体BaTiO3中二波混频的温度效应

研究了光折变晶体钛酸钡中相向传输的二波混频的温度效应,得到在 BaTiO₃中增益耦合系数随温升而增加、并在85℃左右反向.说明其主要载流子的类型在此温度时发生改变.给出了有效陷阱浓度N(T)的温升模型,其理论预期值与实验数据符合较好.     

Photoluminescence of Mg—doped GaN with Different Mg Concentrations after Annealing at Different Temperatures

The blue band (BB) in low temperature photoluminescence of Mg-doped GaN films with different Mg concentrations is investigated.The BB peak of as-grown samples with higher Mg concentration centres at lower energy.A shift of the BB peak energy is observed after annealing in N2 at different temperatures,meanwhile,the difference between the BB peak energy is observed after annealing in N2 at different temperatures.Meanwhile,the difference between the BB peak energies diminishes for raised annealing temperature,and the BB peaks for different samples converge to 2.92eV after annealing at 850℃.These experimental results can be accounted for by a model based on compensation effect.The shift of BB lines provides a useful criterion for the optimum annealing temperature of the Mg-doped GaN material,and the value is taken to be 850℃ in our case.     

电极维度对单分子器件伏-安特性的影响

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聚磷酸酯的合成及其释药性能研究

以三异丁基铝为引发剂研究了２－氢－２－氧－１，３，２－二氧五环磷酸酯的开环聚合反应。聚合产物经氯化、水解，获得了一种新型的交联聚磷酸酯。用交联聚磷酸酯为载体，采用单植片和夹心片的方法式，对左旋－１８－甲基炔诺酮进行了控制释放研究。