40 Gbit/s长途WDM系统及其应用前景

40Gbit/s波分复用(WDM)系统是未来技术发展的方向，也是目前技术研究的热点。本将首先分析40Gbit／sWDM系统所面临的关键技术问题，然后介绍美国PhotonEx公司已经商用化的40Gbit／s WDM系统及其主要技术特点，最后提出40Gbit/s WDM在我国的应用前景，包括应用场合及实现步骤等。     

Noise reduction for magnetic resonance images via adaptive multiscale products thresholding

Edge-preserving denoising is of great interest in medical image processing. This paper presents a wavelet-based multiscale products thresholding scheme for noise suppression of magnetic resonance images. A Canny edge detector-like dyadic wavelet transform is employed. This results in the significant features in images evolving with high magnitude across wavelet scales, while noise decays rapidly. To exploit the wavelet interscale dependencies we multiply the adjacent wavelet subbands to enhance edge structures while weakening noise. In the multiscale products, edges can be effectively distinguished from noise. Thereafter, an adaptive threshold is calculated and imposed on the products, instead of on the wavelet coefficients, to identify important features. Experiments show that the proposed scheme better suppresses noise and preserves edges than other wavelet-thresholding denoising methods.     

3.5代通信中链路自适应技术的研究和仿真

3.5代移动通信中的链路自适应技术使用自适应调制编码和快速混合重传技术替代了3代中使用的功率控制技术。仿真结果比较了这两种新技术与功率控制技术的性能,证明了这两个新技术显著地提高了网络平均的吞吐量。     

CATV分支分配器隔离度及末端应用

了解分支、分配器反向隔离与相互隔离度以及在用户终端的正确使用，为减少用户的相互干扰。提高传输质量，应选用高标准的CATV器材，实现信号的反向隔离。     

机动天基平台惯性/天文导航组合模式研究

为了有效提高惯性/天文组合定姿效果,研究了在机动天基平台条件下惯性/天文导航的7种组合模式在姿态控制方面的应用,进行了理论分析,并对不同的组合模式的定姿结果进行了仿真实验。通过仿真分析了惯性/天文各种组合模式的优缺点,提出了不同组合模式的适用场合,当星敏感器识别恒星为两颗时,采用基于光轴指向的组合模式的效果好于使用星光单位矢量的组合模式;当星敏感器识别恒星超过两颗时,采用基于姿态矩阵的惯性/天文组合模式效果最好,能够更充分地利用星光信息、计算精度高、计算实时性好。     

移动通信终端多媒体系统设计

采用中星微VC0858在CDMA移动通信终端开发平台上实现了多媒体系统,详细介绍了硬件结构和软件系统的设计.测试结果证明该方案符合移动通信终端实际使用要求.     

Mechanistic Considerations of Bending‐Strain Effects within Organic Semiconductors on Polymer Dielectrics

The development of organic transistors for flexible electronics requires the understanding of device behavior upon the application of strain. Here, a comprehensive study of the effect of polymer‐dielectric and semiconductor chemical structure on the device performance under applied strain is reported. The systematic change of the polymer dielectric results in the modulation of the effects of strain on the mobility of organic field‐effect transistor devices. A general method is demonstrated to lower the effects of strain in devices by covalent substitution of the dielectric surface. Additionally, the introduction of a hexyl chain at the peripheries of the organic semiconductor structure results in an inversion of the effects of strain on device mobility. This novel behavior may be explained by the capacitative coupling of the surface energy variations during applied strain.     

Ho:YAG激光心肌血管重建术的实验研究

建立狗急性心肌梗塞实验模型,以SPECT观察钬激光心肌血管重建术后心肌缺血的改善情况及激光孔道的组织学变化,确定钬激光心肌血管重建术的有效性及适宜的激光参数,为钬激光心肌血管重建术的临床应用提供资料.     

Fabrication of organic semiconductor crystalline thin films and crystals from solution by confined crystallization

Highly crystalline thin films of organic semiconductors processed from solution for electronic devices are difficult to achieve due to a slow and preferential three-dimensional growth of the crystals. Here we describe the development of a processing technique to induce a preferential two-dimensional crystalline growth of organic semiconductors by means of minimizing one dimension and confining the solution in two dimensions into a thin layer. The versatility of the process is demonstrated by processing small molecules (TIPS-pentacene and C₆₀) and a polymer (P3HT), all from solvents with a relatively low boiling point, to obtain crystalline thin films. The thin films show an improved in-plane packing of the molecules compared to films processed under similar conditions by spin coating, which is beneficial for the use in organic field-effect transistors.     

Pt纳米颗粒辅助化学刻蚀重掺杂p型单晶硅研究

首先在SiO2/Si衬底上磁控溅射了一层超薄Pt薄膜,并通过快速热退火形成了分离的Pt纳米颗粒阵列。接着研究了在氢氟酸和双氧水的混合溶液中Pt纳米颗粒辅助化学刻蚀重掺杂p型单晶硅片的特性。结果表明,当氢氟酸的浓度为1.06 mol/L时,样品表面分布着许多Pt岛链,在硅衬底表面没有观察到任何孔洞;当氢氟酸的浓度上升到5.3 mol/L时,样品表面起伏不平,出现许多大小不一的小丘,岛链状Pt减少;当氢氟酸的浓度增加到26.5 mol/L时,样品表面出现大量的孔洞,Pt岛链进一步减少。通过对样品的剖面结构进行观察,发现硅衬底中形成了致密的介孔,同时还观察到底部含有Pt岛状物的不规则沟槽,并且介孔的生长速率快于沟槽。最后,对上述实验现象的形成机制进行了讨论。