新型金属杂冠醚配合物18-MC-6[Mn6(4-Amashz)6(DMF)6]·12DMF的合成

合成了一种新型金属杂冠醚配合物[Mn6(4-amashz)6(DMF)6]·12DMF,并用X射线衍射法对其结构进行了表征.研究了该化合物修饰金电极催化氧还原的性质,结果表明,该化合物具有平面碟状结构,对在碱性溶液中的氧有显著的催化还原作用.     

用废旧锂离子电池制备镍掺杂钴铁氧体

以废旧锂离子电池为原料,采用sol-gel法制备了镍掺杂的钴铁氧体。借助XRD、振动样品磁强计(VSM),就镍掺杂量对钴铁氧体结构和磁性能的影响进行了研究。结果表明:以酒石酸为凝胶剂,采用sol-gel法,用废旧锂离子电池可以制备出性能优良的尖晶石结构镍掺杂钴铁氧体;最佳的镍掺杂摩尔分数x(Ni2+)为0.2。     

Multiconstrained QoS multipath routing in wireless sensor networks

Sensor nodes are densely deployed to accomplish various applications because of the inexpensive cost and small size. Depending on different applications, the traffic in the wireless sensor networks may be mixed with time-sensitive packets and reliability-demanding packets. Therefore, QoS routing is an important issue in wireless sensor networks. Our goal is to provide soft-QoS to different packets as path information is not readily available in wireless networks. In this paper, we utilize the multiple paths between the source and sink pairs for QoS provisioning. Unlike E2E QoS schemes, soft-QoS mapped into links on a path is provided based on local link state information. By the estimation and approximation of path quality, traditional NP-complete QoS problem can be transformed to a modest problem. The idea is to formulate the optimization problem as a probabilistic programming, then based on some approximation technique, we convert it into a deterministic linear programming, which is much easier and convenient to solve. More importantly, the resulting solution is also one to the original probabilistic programming. Simulation results demonstrate the effectiveness of our approach. This work was supported in part by the U.S. National Science Foundation under grant DBI-0529012, the National Science Foundation Faculty Early Career Development Award under grant ANI-0093241 and the Office of Naval Research under Young Investigator Award N000140210464. Xiaoxia Huang received her BS and MS in the Electrical Engineering from Huazhong University of Science and Technology in 2000 and 2002, respectively. She is completing her Ph.D. degree in the Department of Electrical and Computer Engineering at the University of Florida. Her research interests include mobile computing, QoS and routing in wireless ad hoc networks and wireless sensor networks. Yuguang Fang received a Ph.D. degree in Systems Engineering from Case Western Reserve University in January 1994 and a Ph.D degree in Electrical Engineering from Boston University in May 1997. He was an assistant professor in the Department of Electrical and Computer Engineering at New Jersey Institute of Technology from July 1998 to May 2000. He then joined the Department of Electrical and Computer Engineering at University of Florida in May 2000 as an assistant professor, got an early promotion to an associate professor with tenure in August 2003 and to a full professor in August 2005. He holds a University of Florida Research Foundation (UFRF) Professorship from 2006 to 2009. He has published over 200 papers in refereed professional journals and conferences. He received the National Science Foundation Faculty Early Career Award in 2001 and the Office of Naval Research Young Investigator Award in 2002. He has served on several editorial boards of technical journals including IEEE Transactions on Communications, IEEE Transactions on Wireless Communications, IEEE Transactions on Mobile Computing and ACM Wireless Networks. He have also been activitely participating in professional conference organizations such as serving as The Steering Committee Co-Chair for QShine, the Technical Program Vice-Chair for IEEE INFOCOM’2005, Technical Program Symposium Co-Chair for IEEE Globecom’2004, and a member of Technical Program Committee for IEEE INFOCOM (1998, 2000, 2003–2007).     

基于神经网络技术的f0F2短期预报方法

利用神经网络技术并考虑太阳和地磁活动对电离层的影响,提出一种提前1h预报电离层临界频率f0F2的方法.网络的输入包括时间、季节、地磁指数、太阳黑子数.太阳射电流量F10.7以及f0F2偏离月中值的一阶和二阶有限差和相对偏差.分别用广州和兰州站的历史数据进行检验,预报结果与观测数据符合得较好,比国际参考电离层更具有实用性.     

视频交通监控系统

随着城市道路的建设与发展，迫切要求对交通控制和监督功能逐步实现自动化，而视频道路数控技术是实现这一功能的重要手段。本文用VC^ 6．0模拟实现了对车速及车流量的实时检测，具有一定的实用性。     

(Y2.94-xGdxCe0.06)Al5O12荧光粉的温度依赖特性研究

主要研究了Gd的掺杂浓度对(Y2.94-xGdxCe0.06)Al5O12荧光粉发射光谱的影响以及发光光谱的温度依赖特性。结果表明:室温(RT)时,随着Gd掺杂量从0增大到0.6mol,(Y2.94-xGdxCe0.06)Al5O12荧光粉发射光谱的峰值波长从530nm红移到550nm;环境温度升高时,(Y2.94-xGdxCe0.06)Al5O12荧光粉的发光强度呈快速衰减、发射光谱呈宽化趋势,且衰减速率及宽化趋势都随着Gd掺杂量的增加而加剧。采用位形坐标模型讨论认为,由于Gd3+的半径和电负性均大于Y3+,Gd3+取代Y3+后,导致发光中心的简并基态和激发态劈裂加剧,基态和第1激发态间的间距减小,激活能下降,发射光谱呈现红移现象。随着温度升高,电子和声子间的相互作用增强,非辐射跃迁增强,发光快速衰减,光谱宽化。利用发光强度、光谱宽度与温度关系公式解释了Gd掺杂量增加导致热衰减加剧、光谱宽化趋势愈加明显的现象。     

一种双阻带红外频率选择表面

为实现中、远红外大气窗口的双波段低红外透过率,设计了由2层不同尺寸圆环单元构成的双屏红外频率选择表面(FSS),仿真结果表明该FSS在3~5μm和8~12μm波段形成两个平均透过率低于5%的阻带.对FSS表面电流分析的结果说明,谐振单元表面感应出的对称分布电流使散射总场增强,形成增强型反射,而不同尺寸的谐振单元具有不同的谐振波长,两层谐振单元共同作用形成了两个阻带.研究了入射角以及介质层属性(厚度、介电常数和损耗角正切)对FSS传输特性的影响,结果表明FSS在两个大气窗口内具有良好的角度稳定性,介质层介电常数对FSS的传输特性有较大影响.     

TFT-LCD中驱动信号对线残像的改善研究

通过对TFT-LCD去隔行扫描输入信号易产生线残像的问题进行分析,考察线残像产生的原因与驱动信号之间的关联。结果表明,通过改变驱动信号的极性反转方式可以改善线残像,但改善线残像同时却带来了闪烁问题。经过进一步研究分析,通过增加预充电信号以及控制TFT特性的开关比可以有效解决改善输入信号后带来的闪烁问题,并给出了相应的原理解释。为线残像的分析和改善提供了解决方法和理论依据。     

宽带城域网及其增值业务

城市信息化离不开城市信息高速公路 ,宽带城域网的建设为城市信息化提供了高速通道。IP网和ATM网将是宽带城域网的核心平台 ,宽带接入技术将成为城域网接入的主要手段 ,宽带城域网整体解决方案离不开IP软技术的应用 ,三网融合将是宽带城域网发展方向。增值业务是网络不断发展的动力所在     

Cypate‐Conjugated Porous Upconversion Nanocomposites for Programmed Delivery of Heat Shock Protein 70 Small Interfering RNA for Gene Silencing and Photothermal Ablation

Synergistic therapy is an accepted method of enhancing the efficacy of cancer therapies. In this study, cypate‐conjugated porous NaLuF₄ doped with Yb³⁺, Er³⁺, and Gd³⁺ is synthesized and its potential for upconversion luminescence/magnetic resonance dual‐modality molecular imaging for guiding oncotherapy is tested. Loading cypate‐conjugated upconversion nanoparticles (UCNP‐cy) with small interfering RNA gene against heat shock protein 70 (UCNP‐cy‐siRNA) enhances the cell damage. UCNP‐cy‐siRNA exhibits remarkable antitumor efficacy in vivo as a result of the synergistic effects of gene silencing and photothermal therapy, with low drug dose and minimal side effects. This result thus provides an explicit strategy for developing next‐generation multifunctional nanoplatforms for multimodal imaging‐guided synergistic oncotherapy.