900℃空气退火对L-MBE生长的ZnO薄膜发光特性的影响

采用激光分子束外延法在蓝宝石衬底(0001)上生长了高度c轴择优取向的高质量ZnO薄膜,在空气中对生长的薄膜进行900℃退火处理,并对退火前后样品的结晶质量、发光特性采用X射线衍射(XRD)、变温光致发光(PL)研究.退火处理后的ZnO薄膜(0002)面XRDθ-2θ扫描曲线强度明显增强.在光致发光实验中,观测到薄膜分别在3.352,3.309和3.237eV附近有3个明显的近紫外发光峰,分别对应自由激子发射、中性施主或受主束缚激子I9及其声子伴线1Lo.随着温度升高,峰位逐渐向长波方向移动(即所谓"红移"),半高宽(FWHM)逐渐展宽;在发光谱中,来自于晶体缺陷的深能级(DL)区发光强度极小.     

曲线光顺在惯导平台自标定中的应用

提出了一种新的惯导平台自标定数据处理方法——曲线光顺法。根据自标定数据特点给出了适于自标定数据的曲线光顺准则。分析了野值对曲线二阶差商的影响规律,提出了一种野值剔除算法。通过将最小二乘与B样条结合得出二阶差商参考值,并使实际差商与参考差商距离达到最小从而得到野值修改值。实验结果表明,该文的算法能很好地解决惯导平台自标定数据的野值剔除问题,可通过调节参数来控制光顺精度,并具有算法简便、易于操作的优点。     

高效无损岩心孔隙度精确测量新方法

将微纳米CT图像与微图像拼接技术相结合,识别出干酪根内微纳米尺度孔隙,从而对岩心孔隙度进行精确测量。首先利用微纳米CT图像,识别出其中的宏观连通孔隙度、孤立孔隙度以及干酪根区域（无法辨识的干酪根孔隙）所占体积百分比;然后借助扫描电镜或FIBSEM图像,对微纳米CT图像中的干酪根区域进行超高分辨率成像,识别出干酪根孔隙空间,并通过九格法测量有代表性的样品点计算出干酪根本身的平均孔隙度;最后将超高分辨率下得到的干酪根孔隙度信息,返回到微纳米CT图像中的干酪根区域内,修正微纳米CT图像宏观总孔隙度。整个测量过程操作简便,并且不对岩心造成实质性伤害。     

TM1300多媒体DSP的百兆以太网通信接口的设计实现

主要研究TM1300多媒体数字信号处理器(DSP)在pSOS嵌入式操作系统下的100 Mbit/s高速以太网接口的设计与实现.硬件方面,介绍了TM1300系统与RTL8139以太网驱动芯片通过PCI总线互连的实现方式,重点介绍了其中PCI仲裁器的设计和PCI配置空间地址的设置方法;软件方面,介绍了在DSP端内嵌的pSOS操作系统下开发软件驱动RTL8139芯片的方法,重点描述了pSOS的pNA 网络组件的NI接口、RTL8139芯片收发数据的控制方式、驱动程序的发送缓存管理、TM1300访问PCI空间的途径以及内存与数据缓存一致性等要点.最后从速率、可靠性、效率3个方面对实现的以太网通信接口进行了测试,给出了详细的实测结果.测试结果显示,与基于RTL8029芯片开发的以太网接口相比,各项性能均有较大提高.     

镍基裂解汽油一段加氢催化剂研究进展

介绍了镍基裂解汽油一段加氢催化剂的工业应用状况及研究进展,指出了提高裂解汽油一段镍基催化剂加氢性能的途径及该领域最新发展趋势。     

A new technique for boosting efficiency of silicon solar cells

A new type of photovoltaic system with higher generation power density has been studied in detail. The feature of the system is a V-shaped module (VSM) with two tilted monocrystalline solar cells. Compared to solar cells in a flat orientation, the VSM enhances external quantum efficiency and leads to an increase of 31% in power conversion efficiency. Due to the VSM technique, short-circuit current density was raised from 24.94 to 33.7 mA/cm², but both fill factor and open-circuit voltage were approximately unchanged. For the VSM similar results (about 30% increase) were obtained for solar cells fabricated by using mono-crystalline silicon wafers with only conventional background impurities.     

多学科视野下中国近代造园理论的源流与建构研究

造园是一种"综合的技术"、一门"综合之科学",这成为中国近代一些接受或接触过造园专业教育的学者的共识;同时,园艺、林业、市政、建筑等近代业已确立的学科开展了与造园相关的教育活动,相应则有汲取外来理论、立足本土传统的诸多理论探索与建设.这种知识进展与汇聚的"量变"是1951年"造园组"创立这一"质变"的历史基础.通过回溯...     

Nanocarrier‐Mediated Codelivery of Small Molecular Drugs and siRNA to Enhance Chondrogenic Differentiation and Suppress Hypertrophy of Human Mesenchymal Stem Cells

Cartilage loss is a leading cause of disability among adults, and effective therapy remains elusive. Human mesenchymal stem cells (hMSCs), which have demonstrated self‐renewal and multipotential differentiation, are a promising cell source for cartilage repair. However, the hypertrophic differentiation of the chondrogenically induced MSCs and resulting tissue calcification hinders the clinical translation of MSCs for cartilage repair. Here, a multifunctional nanocarrier based on quantum dots (QDs) is developed to enhance chondrogenic differentiation and suppress hypertrophy of hMSCs simultaneously. Briefly, the QDs are modified with β‐cyclodextrin (β‐CD) and RGD peptide. The resulting nanocarrier is capable of carrying hydrophobic small molecules such as kartogenin in the hydrophobic pockets of conjugated β‐CD to induce chondrogenic differentiation of hMSCs. Meanwhile, via electrostatic interaction the conjugated RGD peptides bind the cargo siRNA targeting Runx2, which is a key regulator of hMSC hypertrophy. Furthermore, due to the excellent photostability of QDs, hMSCs labeled with the nanocarrier can be tracked for up to 14 d after implantation in nude mice. Overall, this work demonstrates the potential of our nanocarrier for inducing and maintaining the chondrogenic phenotype and tracking hMSCs in vivo.     

Process optimization of a deep trench isolation structure for high voltage SOI devices

In this work, the process reasons for weak point formation of the deep trench on SOI wafer have been analyzed in detail. The optimized trench process is also proposed. It is found that there are two main reasons: one is over-etching laterally of silicon on the surface of buried oxide caused by fringe effect; the other is slowly growth rate of isolation oxide in the concave silicon corner of trench bottom. In order to improve the isolation performance of deep trench, two feasible ways for optimizing trench process are proposed. The improved process thickens the isolation oxide and rounds sharp silicon corner at weak point, increasing the applied voltage by 15-20V at the same leakage current. The proposed new trench isolation process has been verified in foundry’s 0.5-μm HV SOI technology.     

太阳能半导体空调制冷装置模块化实验研究

建立了以水为热交换媒介的太阳能热电模块制冷实验系统.系统配置了双位能量存储装置,用以储存昼夜温差能和太阳光电转换电能,以备无日照或日照不足时系统能够连续工作.热电制冷装置模块化,用以适应制冷功率变化较大的空间制冷,并在制冷启动与温度维持不同阶段实现较大功率的切入或撤出.制冷模块以半导体热电元件为核心,冷热端均以导热性能良好的紫铜作为热交换材料,以热容量较大的水作为冷却液和散热循环液.热交换装置采取集合散热冷却分流的集散一体化热交换系统.对制冷模块制冷性能进行了实验分析,并对制冷效果进行了模拟实验,实验结果基本达到了设计的预期.