沉积参数对CVD金刚石晶粒尺寸的影响

采用DC Arc Plasma Jet CVD方法制备了金刚石自支撑膜体,考察了温度分布、沉积腔压和CH4/H2等沉积参数对所制备金刚石膜体中的晶粒尺寸的影响.实验发现沿温度降低的方向和增加腔压会使晶粒尺寸变大,当CH4/H2超过15%后,有带刻面的晶粒出现.本次实验最大的晶粒对角线长度超过1mm.     

Syndrome trellis codes based on minimal span generator matrix

To improve the embedding efficiency of steganography, syndrome coding based on the coding theory has attracted many researchers’ attentions. In this paper, we make use of the relationship between syndrome coding for minimizing additive distortion and maximum likelihood decoding for linear codes to analyze the main parameters of convolutional codes which influence the embedding efficiency. And, the new syndrome trellis codes based on minimal span generator matrix is proposed. It can be considered an alternative construction of the state-of-the-art syndrome trellis codes (STCs) proposed by Filler and Fridrich recently. Experimental results show that the proposed scheme owns the same embedding performance to STCs and achieve the reduced time complexity and storage requirement meanwhile.     

S-band gain flattened distributed fiber Raman amplifier with chirped fiber bragg grating filter

IPTV,video-phone,video-conference,distance learn-ing,distance medical ,e-governmental affairs ,etc .will be-come commonthings in people' s daily life with the fastdevelopment of Internet technology.During this processextra-capacity of fiber communication …     

基于指标改善的家宽业务满意度提升研究

进入5G移动互联网时代,家宽重要性不言而喻。在实际的工作中,家宽端到端的长流程、多样业务形态与不透明的用户侧组网导致家客用户满意度影响因素众多,在提升家宽业务用户满意度过程中遇到了"时效低、定位难、缺抓手、无闭环"四大难题,给运维支撑与满意度提升工作带来较大压力。基于此,文章从客户属性、业务质量、服务质量等三个方面建立家宽业务满意度分析模型,实现对用户满意度问题的精确识别、支撑前移与闭环跟踪。     

Design and fabrication of ultra-small overlapped AWG demultiplexer based on /spl alpha/-Si nanowire waveguides

A novel layout for an ultra-compact arrayed-waveguide grating (AWG) demultiplexer is presented. The present layout has two overlapped free propagation regions, and is more compact than a conventional layout. Using /spl alpha/Si-on-SiO/sub 2/ nanowire waveguides, an ultra-small 4/spl times/4 AWG (about 40/spl times/50 /spl mu/m/sup 2/) with channel spacing of 11 nm is fabricated and characterised.     

全高程脉冲压缩雷达高度表的实现

叙述了线性调频脉冲压缩体制雷达高度表工作原理,介绍了普通脉冲压缩体制雷达高度表在低高度应用中存在的问题和解决途径,实现了脉冲压缩体制雷达高度表从低高度(起飞)到高高度的全程工作,以避免脉压体制和脉冲体制组合使用所带来的系统测高误差.并经机载试验验证,实现了脉冲压缩雷达高度表全高程工作.     

Bone Plate Composed of a Ternary Nanohydroxyapatite/Polyamide 66/Glass Fiber Composite: Biocompatibility In Vivo and Internal Fixation for Canine Femur Fractures

Bone plates have been applied to fix fractures for over a hundred years. Metal plates are the gold standard. However, an increasing number of clinical practices and animal experiments have shown that metal plates have had incidents of failure due to their rigid fixation and long‐term complications. Degradable composites present the advantages of a lower elastic modulus and absorbable properties but are unsuitable for load‐bearing applications. Nondegradable bone plates composed of a nanohydroxyapatite/polyamide 66/glass fiber (n‐HA/PA66/GF) composite are prepared, which have enough strength and a low elastic modulus for an internal fixation device. To better assess its function as a bone plate, animal experiments are conducted using a canine load‐bearing femur fracture model. The results show that the n‐HA/PA66/GF plate can fix fractures effectively. Gross observation, radiographic films, and histological analysis all show that the n‐HA/PA66/GF plate leads to a secondary (indirect) union with obvious callus formation, whereas the titanium plate leads to primary (direct) union due to rigid fixation. Furthermore, the histological results reveal that new bone grows at the interface and that the n‐HA/PA66/GF plate can integrate with native bone tissue. Consequently, the n‐HA/PA66/GF composite shows good potential as a bone plate to fix loading‐bearing bone fractures.     

Size Effects on the Mechanical Properties of Nanoporous Graphene Networks

It is essential to understand the size scaling effects on the mechanical properties of graphene networks to realize the potential mechanical applications of graphene assemblies. Here, a “highly dense‐yet‐nanoporous graphene monolith (HPGM)” is used as a model material of graphene networks to investigate the dependence of mechanical properties on the intrinsic interplanar interactions and the extrinsic specimen size effects. The interactions between graphene sheets could be enhanced by heat treatment and the plastic HPGM is transformed into a highly elastic network. A strong size effect is revealed by in situ compression of micro‐ and nanopillars inside electron microscopes. Both the modulus and strength are drastically increased as the specimen size reduces to ≈100 nm, because of the reduced weak links in a small volume. Molecular dynamics simulations reveal the deformation mechanism involving slip‐stick sliding, bending, buckling of graphene sheets, collapsing, and densification of graphene cells. In addition, a size‐dependent brittle‐to‐ductile transition of the HPGM nanopillars is discovered and understood by the competition between volumetric deformation energy and critical dilation energy.     

Pillar[5]arene-Modified Gold Nanorods as Nanocarriers for Multi-Modal Imaging-Guided Synergistic Photodynamic-Photothermal Therapy

Supramolecular approaches have opened up vast possibilities to construct versatile materials, especially those with stimuli-responsiveness and integrated functionalities of multi-modal diagnosis and synergistic therapeutics. In this study, a hybrid theranostic nanosystem named TTPY-Py⊂CP5@AuNR is constructed via facile host–guest interactions, where TTPY-Py is a photosensitizer with aggregation-induced emission and CP5@AuNR represents the carboxylatopillar[5]arene (CP5)-modified Au nanorods. TTPY-Py⊂CP5@AuNR integrates the respective advantages of TTPY-Py and CP5@AuNR such as the high performance of reactive oxygen species generation and photothermal conversion, and meanwhile shows fluorescence responses to both temperature and pH stimuli. The successful modification of CP5 macrocycles on AuNRs surfaces can eliminate the cytotoxicity of AuNRs and enable them to serve as the nanocarrier of TTPY-Py for further theranostic applications. Significantly, in vitro and in vivo evaluations demonstrate that this supramolecular nanotheranostic system possesses multiple modalities including intensive fluorescence imaging (FLI), photoacoustic imaging (PAI), efficient photodynamic therapy (PDT), and photothermal therapy (PTT), indicating its great potential for FLI-PAI imaging-guided synergistic PDT-PTT therapy. Moreover, TTPY-Py can be released upon activation by the acidic environment of lysosomes and then specifically light up mitochondria. This study demonstrates a new strategy for the design of versatile nanotheranostics for accurate tumor imaging and cancer therapies.     

Comments on “Multiphase systolic algorithms for spectraldecomposition” [and reply]

Comments that the paper by Liu and Yao (see ibid., vol.40, no.1, p.190, 1992) presented an efficient algorithm for spectral decomposition, but the parallel algorithm and architecture for the Hessenberg reduction has a problem. The matrix obtained from the unitary similarity transformation is not necessarily a Hessenberg matrix. The authors reply that the Hessenberg reduction described is not in the Hessenberg form. Only the first column is in its proper form. There are many ways to overcome such a problem. One simple way is to use the multiphase rectangular systolic array