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In this work, spark ablation method is used to generate silver nanoparticles, which are deposited on a silicon substrate to prepare a silver conductive film. The element, purity, film thickness, microstructure and electrical conductivity of silver conductive film were measured by X-ray diffractometer, energy dispersive spectrometer, step profiler, four-point probe tester and scanning electron microscopy. The conductive film is heated by thermal sintering to promote the agglomeration of silver nanoparticles to reduce the resistivity of the film. The influences of sintering temperature on the conductivity of the films were investigated. The results showed that when the sintering temperature is 300°C and the sintering time is 30min, the silver conductive film deposited for 20min with a thickness of 4 µm and the electrical conductivity of 4.31×106 S m−1 can be attained.

With the increasing requirements of the electronic industry for the performance of packaging and interconnection materials, it is the driving force for the use of metal nanoparticles as chip interconnection materials in the field of microelectronics. Due to the small size effect, metal nanomaterials have the characteristics of “low temperature sintering, high temperature service”, and are considered as a good substitute for tin based solder. High purity and small size metal nanoparticles can be prepared by spark ablation without any chemical reaction. In addition, aerosol lines for gas production are continuous and have the potential to expand production. This method can be used for the preparation of semiconductor, metal, oxide, multicomponent mixed nano materials and alloys. In this paper, the preparation of silver nanoparticles by spark discharge ablation of silver target in inert gas was studied systematically. By adjusting the spark discharge parameters and gas flow rate, dispersed and non agglomerated particles or aggregates with an average size of about 20 nm were prepared. The size distribution, morphology, structure, conductivity and thickness of silver layer were characterized by scanning electron microscope (SEM), four point probe resistance test and profilometer. The experimental results show that the silver nanoparticles produced by high purity gas are very clean and can be sintered at low temperature and low pressure, which can meet the requirements of packaging interconnection performance.

High strength Cu-Cu interconnections of direct bonded copper substrate are achieved by low-temperature and low-pressure sintering of Cu micron-nanoparticles mixed in different mass ratio. The copper micronparticles with a particle size of 1μm and copper nanoparticles with a particle size of 200 nm were mixed in a certain mass ratio (for example, the mass ratio is 0/10, 1/9, 3/7, 5/5, 7/3, 9/1, 10/0). A certain amount of copper micronparticles was added to the Cu nanoparticles solution. After mixing and vacuum homogenization, a copper micron-nanoparticles paste is obtained. When sintering at the temperature of 260°C, a sintering pressure of 2 MPa and a reduced atmosphere of 5 % hydrogen and 95% argon for 30 minutes, the interconnection joints were obtained. The shear test showed the interconnection strength of the 7 different mass ratio copper pastes. Among them, the sintering strength of the copper paste with a mass ratio of 3/7 is 43.66 MPa. In a conclusion, the microstructure analysis demonstrated that the Cu-Cu joints were formed between the copper paste and the pad. Analyzing the shear section, the fracture layer of the copper paste was in a tensile fracture state. The copper paste with a mass ratio of 3/7 had the best sintering performance realizing the dense sintering of the copper paste at low temperature and low pressure, and the shear strength can reach 43.66 MPa.

Asian ladybird beetle (Harmonia axyridis) is a kind of tiny flapping insects whose hind wings can be deployable for flight. The folding/unfolding mechanism of the hind wing gives inspiration to design the bionic deployable wing for flapping-wing micro air vehicles (FMAVs). The main veins of H. axyridis are hollow that are helpful for the deformation including hind wing folding and unfolding process. Based on the veins structure morphologies observed by slicing test and inverted fluorescence microscopy, the three-dimensional (3-D) model of wing frame of folding/unfolding wing can be designed for FMAVs and will be static analyzed next. The main wing frame is designed as hollow structure which can decrease the mass of wing and is useful for folding. The static analysis results show the significant factors of the wing structure optimized for FMAVs.

At present, the mainstream method of LCP multi-layer lines is to use a layer of low melting point LCP to bond the lines. However, during the high-temperature compression process, LCP will flow and cause the thickness of the circuit to be uneven, which will affect the impedance of the circuit and cause impedance discontinuities. May drift; the lamination temperature of multi-layer LCP lines is too high, and the LCP pressure flow at high temperature can only be pressed at one time, the alignment accuracy is low, and the reliability of the line is affected, and high temperature presses require high temperature presses, which are expensive .This article provides a method for multi-layer LCP low-temperature lamination. Multi-layer liquid crystal polymer (LCP) circuits are obtained by a thin layer of low-temperature vacuum hot pressing. Multilayer LCP lines have little difference in insertion loss at 5G frequency, and there is no bubble delamination between layers, and the peel strength is high.

For high resolution synthetic aperture radar (SAR) applications, an active phased antenna module has been developed, where a broadband, highly efficient waveguide slot antenna is used as its passive radiator. A prototype has been fabricated and tested. Excellent performance is achieved through experiments, which thereby validates the concept of design.

The folding/unfolding hind wings of Asian ladybird beetle (Harmonia axyridis) show remarkable flight performance and the veins of hind wings have a significant influence on its flight performance. The structure morphologies of the veins of H. axyridis hind wing are investigated to obtain the thickness of wing membrane and the diameter of veins for the design of three-dimensional (3-D) model. Additionally, considering the hollow veins of hind wing observed by scanning electron microscopy (SEM), mechanical properties of hind wing for H. axyridis flight are researched. The static analysis results shown that the variation tendency of the total deformation of the hind wing are almost relationship with −60°, −30°, 0°, 30° and 60° of attack angles and the locations of the pressure setting. The total deformation of H. axyridis hind wings during flight in different attack angles influenced will be helpful to design the flight performance of biomimetic micro air vehicles (MAVs).

The steady and dynamic rheology and thixotropy of corn starch dispersions in pre-gelatinized starch solution were studied using AR500 rheometer. The effects of temperature, concentration and frequency on the viscosity were investigated, respectively, and the rheological mechanism of dispersions was illustrated clearly. The rheological tests indicate that corn starch dispersions experience two stages which are shear thinning and shear thickening. Compared with the temperature, the apparent viscosity is more sensitive to the concentration at low shear rate in steady rheological measurements. It also reveals that angular frequency has more significant effects on the critical oscillatory shear stress. The greater the concentration, the higher the thixotropic energy is, and showing extreme thixotropic behavior. These are mainly due to the internal continuous network structure of dispersions destroyed at low shear rate and starch granules aggregated into particle clusters at high shear rate.

Bacteriophages are ideal recognition elements for bacterium because of specificity and high affinity in the field of biosensors. The effect of bimolecular immobilization directly influences the performance of biosensors, so orientation immobilization of bacteriophages is of great importance to the biosensors. This article reviews the recent progress in biosensors that used a variety of strategies for the immobilization of bacteriophages to make a correct orientation to the host bacterium. We conclude the advantages and disadvantages of different types of immobilization and provided some directions of orientation immobilization for the future. Wherever possible, sensing performance of each immobilization will be evaluated and compared in terms of sensitivity and detection limit.

The special structural and mechanical characteristics of beetle elytral cuticle will be instructive in bionic for designing composites materials. Because the microscale or nanoscale thickness of the beetle cuticle, it was difficult to determine the cuticle's mechanical characteristics until nanoindentation techniques were developed. The nanomechanical characteristics (reduced modulus Er and hardness H) of dung beetle Copris ochus Motschulsky cuticle were investigated by nanoindenter. To understand water's effect, samples were tested immediately or after different amounts of time. The nanoindentation results showed that the mechanical characteristics were strongly influenced by sample aging and that Er and H increased with a decrease in water content. The results were discussed in following about relationship of the mechanical characteristics of the cuticle and its behaviors.

In this paper, we present a novel scheme using dual-wavelength lights to suppress the nonlinear intermodulation distortion in intensity-modulated radio-over-fiber link both theoretically and experimentally. More than 26 dB suppression of the third-order intermodulation distortion (IMD3) is achieved after 5.1km single mode fiber transmission; and the error vector magnitude of the proposed scheme is reduced from 18.26% to 8.06% after linearization.

The paper proposes a method to analyze the sources. Under complicated environments, for example, there are different types of sources existing in the far field or more than one source in the same direction, common array processing methods do not consider these situations. But they will bring difficulty when we want to acquire the characteristics of these sources. Some sources may be indistinguishable in space, but they may be distinguishable in time-frequency domain, which we can use while analyzing the sources. The paper adopts spatial filtering and time frequency distribution (TFD) to deal with these situations. Spatial filtering can keep the sources in a particular direction from being interrupted by sources in other directions and extract the original signals in that direction, while TFD is used to analyze the extracted signals in time-frequency domain to get some information of signals of the sources, such as the frequency range. Simulation results prove the effectiveness of the method.

To verify the ground moving target indication (GMTI) ability of low-frequency multi-channel synthetic aperture radar (SAR), a vehicle-borne experimental system has been set up by National University of Defense Technology. Considering the low frequency property of the system, a signal processing procedure is proposed involved in long coherent processing interval (CPI) methods. Some crucial issues in the pre-process for moving target detection are also discussed in this paper. Through the outfield experiment, it is validated that the system can detect moving targets with small Radar Cross Section (RCS) or slow velocity.

This paper presents the first version of the NIST Cloud Computing Reference Architecture (RA). This is a vendor neutral conceptual model that concentrates on the role and interactions of the identified actors in the cloud computing sphere. Five primary actors were identified - Cloud Service Consumer, Cloud Service Provider, Cloud Broker, Cloud Auditor and Cloud Carrier. Their roles and activities are discussed in this report. A primary goal for generating this model was to give the United States Government (USG) a method for understanding and communicating the components of a cloud computing system for Federal IT executives, Program Managers and IT procurement officials.

The microstructure of chlamys farreri shell was observed by SEM, the results showed that the chlamys farreri shell is a kind of biological ceramic composite, which is composed of calcite, aragonite and collagen. The calcite layer has irregular laminated structure, and the aragonite layer has regular laminated structure which are composed of staight aragonite strips. The chlamys farreri shell was researched by nanoindentation test, it was shown that both hardness and elastic modulus of aragonite layer are larger than those of calcite layer. It was illustrated that the carrying capacity of aragonite layer is higher than that of calcite layer under same conditions. According to the further observation of nanoindentation apperance of chlamys faerreri shell, the crack propagation modes of two materials are different when they are loaded by external force. The crack shape of calcite is irregular, and the cracks extend along with direction of crystal boundaries, and the capacities of anti-failure and deformation are poor; but the crack of aragonite layer is relative straight, and the amount is less, so the capacities of anti-failure and deformation is preferable. The aragonite layer has excellent mechanical properties.

Electric responses of impedance immunobiosensor for E. coli O157 : H7 at multi-frequencies were explored by complex Td factor correction method. The Corrected data were fitted using least-square method to get the Cole-Cole parameters, and then the relationship between the concentration of bacteria and these parameters was researched. The results showed that the complex Td correction could rectify the complex impedance data for the biosensor at all frequencies indeed, thereby eliminate the “Hook Effect” perfectly and reduced the interference of parasitic capacitance satisfactorily. In particular for impedance data at sweeping time equals to 120 seconds, the Cole-Cole parameters (R0, R∞, fc, ±) are very sensitive to the antigen concentrations. This would provide enriched and reliable information for the qualitative and quantitative test of bacteria with the biosensor.

The quality of product development is affected directly by the quality and efficiency of early stage evaluation and decision of product design scheme; therefore, it is necessary to transfer vague requirements information from customer perspective to design, quantity, and engineering data. In this paper, a model of quality function deployment (QFD) was established, aiming at solving the fuzziness and uncertainty of early stage product design scheme. α-cuts fuzzy weighted average method was used to solve the model to transfer customer requirements information to technology data objectively and accurately. This method was tested by empirical study in the end of this paper.

On the basis of analyzing the characteristics of scanning line point cloud and comparing methods already existed, Algorithms for point cloud preprocessing based on divide-and-conquer strategy is presented. It adopts topological spatial neighborhood theory. Firstly point cloud is distributed to little cubes (square is regarded as degraded cube), then according to cube's space 26-neighbor relationship, the maximum connected region (MCR) including scanning line point cloud is generated and the data out of MCR is deleted as noises. Using the layering feature and square's 8-neighbor connection, the combination of point's sensor property and minimum distance criteria is used for outliers abridging and multi-sensor data integration. Presented algorithms only need to setup the length of cube edge d and the time used for preprocessing of scanning line data including 200,000 points or so does not exceed 8s on common computer. The data preprocessing results and reconstructed surface model show that the algorithms is so effective and efficient that can meet subsequent requirements.

Taking into account ultra-fast carrier dynamics, we have numerically analyzed 640Gbit/s to 80Gbit/s demultiplexing scheme based on nonlinear polarization rotation (NPR) in a single semiconductor optical amplifier (SOA) in detail. Simulated results show that there is a trade-off in the width and amplitude of switching window induced by clock pulse in terms of the input clock pulse energy. The rise time of switching window does not strongly depend on clock pulse energy, whereas the FWHM and fall time of switching window are increasing with the increase of the clock pulse energy. We have also obtained demultiplexing results from 640Gbit/s to 80Gbit/s based on NPR with a clear open eye diagram. From the simulated analyses, it is clear that for the higher output channel suppression ratio, the input clock signal with TE mode is required.

Taking into account ultra-fast carrier dynamics, we model 640Gbit/s wavelength conversion based on nonlinear polarization rotation (NPR) in a single semiconductor optical amplifier (SOA) and investigate the performance of three kinds of wavelength conversion schemes: one only based on NPR and the other two based on NPR assisted with sideband filtering. Simulated results show that the three kinds of wavelength conversion schemes are achieved with clear open eye diagrams and have signal regeneration capability at 640Gbit/s. To further investigate the performance of three kinds of wavelength conversion schemes, the dependence of output extinction ratio (ER) on some key parameters used in simulation is illustrated. Simulated analyses show that the wavelength conversion based on NPR assisted with blue-shifted filtering scheme exhibits the best performance in terms of the maximum output ER for wavelength conversion and the maximum dynamic range of input power for signal regeneration.

Natural biomaterials are complex composites in hierarchical structure and multifunction. They have some special structures and functions because of their evolution through the exchanges of energy, matter and information with their surroundings over millions of years. The cuticle represents 25% of the dry weight of the entire insect body. It is tenacity, waterproof and lightweight which is an excellent crude composite material. An increasing interest in bionic design of materials based on structures of natural biomaterials has led to the nanomechanical characterization of biomaterials. Quantitive measurement of mechanical properties of insect cuticle will help to develop biomimetic materials suitable for industrial products. Field emission scanning electron microscopy (FESEM) was used to investigate the detail structure of elytra cross section in transverse direction and longitudinal direction. Shown in transverse direction, the fibers of the deeper layers of the endocuticle are orientated in rotation angle and neighbor fibers are rotated in relation to the each other in the same direction. While the fibers in longitudinal direction show the epicuticle, exocuticle and endocuticle clearly hierarchically structure in parallel. In this work, the mechanical properties of the elytra cuticle of dung beetle Copris ochus Motschulsky, reduced modulus and hardness in nano-scale, were investigated by using a nanoindenter. The reduced modulus (E v ) and hardness (H v ) of surface cuticle in the vertical direction obtained by nanoindentation was 5.96 ± 0.32GPa and 0.32 ± 0.09GPa, respectively. The nanoindentation result was shown that the reduced modulus (E t , E l ) and hardness (H t , H l ) of each layer was gradually reduced from the outer layer to the inner layer in the transverse direction and the longitudinal direction, respectively. E v was less than the largest E t presented at outer layer (7.34 ± 0.27GPa) and was larger than that of E l (6.05 ± 1.12GPa) which shows the anisotropy of chitin fibers. It was supposedly formed as a result of the composite effect of the hierarchically structure.

The surface materials and structures of insect cuticle can provide useful information for designing anti-adhesion components material. Quantitive measurement of mechanical properties of insect cuticle will help to develop biomimetic materials suitable for industrial products. In this work, the mechanical properties of the cuticle of dung beetle Copris ochus Motschulsky, reduced modulus and hardness in nano-scale, were investigated by using a nanoindenter. It was shown that the nanomechanical properties of the cuticle were change with each layer of the cuticle. The modulus and hardness in cross section was gradually reduced from the outer layer to the inner layer. And the value in the outer layer is larger than that in vertical direction. So we can suppose that its vertical nanoindentation was resulted from the composite effect of the all layers.

There are many factors which may effect network blocking probability in Automatically Switched Optical Network (ASON), such as call rate, average connection holding time, bandwidth etc. In this paper, the ASON network is simulated by Network Simulator 2 (NS2) and two uniform models which contain these factors are proposed to investigate ASON blocking probability. One model is focused on the call characteristic and another model is focused on the resource occupation. The simulation result shows that the two models can reflect ASON network blocking well. Other factors which may influence ASON blocking probability but cannot put into the models are also discussed, including: link time delay, control plane topology and transport plane topology. These models and factors can give an overall description of network blocking in ASON.

Network processor (NP) is a kind of programmable processor performing network computing, usually used to build a router. It is a new challenge that NP is used to build not only a router but also a data stream shaper. In this paper, the combination of routing algorithm and QoS assembly algorithm for OBS network is implemented using NP, besides, some key design issues such as the fast packet forwarding, the implementation of assembly algorithm and queuing discipline are also discussed in detail. The result shows that the edge router designed is capable of forwarding data streams coming from Ethernet at the average speed of about 880 Mbps.

In the optical burst-switching (OBS) system, IP-over-WDM network has been paid great attention due to its bandwidth efficiency and adaptive traffic load accommodation. However, the abrupt burst for large traffic loads will result in unbearable performance degradation in the traditional JET network. To combat with the load sensitivity, a wavelength-routed OBS (WR-OBS) network architecture was confirmed effective. We have proposed a distributed control WR-OBS network architecture combining JET protocol with a two-way reservation method. Based on this architecture, two new resource reservation protocols are compared by evaluating performance. Computer simulation results demonstrate that improvement of burst blocking probability can be achieved in backward reservation protocol and all these two control protocols outperform traditional JET OBS network.

In this paper, a new method for timing estimation and delay spread estimation using subblock correlation in OFDM systems is proposed. We use the subblock correlation between the cyclic prefix and copied data to estimate symbol timing. The subblock correlations also give information about the delay spread. When the channel variation is slow, we can periodically reset the length of the cyclic prefix, which is just long enough to cover intersymbol interference (ISI). The efficiency of these techniques is demonstrated by the simulation results.

In a traditional time-hopping multiple access ultra-wideband communication system, the orthogonal time-hopping sequence can be designed to improve system performance. However, system capacity is restrictive. We propose a new multiple access system model for a UWB downlink and deploy orthogonal design in three dimensions: time-hopping code, multiuser code, and pulse waveform, or equivalently the position, polarity, and shape of a basic pulse. Such a system provides more freedoms than a traditional time-hopping system. Thus, it is more robust to multiple access interference and can support more users. Performance of the system is analyzed and verified by simulations.