Proxy Multisignature Scheme with （t, m） Threshold Shared Verification

A proxy multisignature scheme with （t, m） threshold shared verification is first proposed based on elliptic curve. In proposed scheme, a proxy signer can sign a message on behalf of n original signers for specific group of verifiers and only any t or more verifiers together in the specific group of verifiers are able to verify the validity of the proxy multisignature on behalf of the group of specific verifiers, but t-1 or fewer verifiers can not. Since the proposed scheme is constructed based on elliptic curve, it requires smaller bandwidth and achieves more secrecy of data transmission; it is more etffcient for signature and verification etc.     

A high-performance narrowband high temperature superconducting filter

Recent development of a high-performance narrowband high-temperature superconducting (HTS) filter is presented. A 10-pole quasi-elliptic function response filter with two pairs of transmission zeros (for high selectivity), which has a center frequency of 2.185 GHz and a 3 dB bandwidth of 10 MHz (a fractional bandwidth of 0.45%), is introduced. The filter was fabricated on a 40 mm×16 mm×0.5 mm MgO wafer with double-sided YBCO films. The measured results show that the filter has 0.15 dB insertion loss at the ...     

Top-gated graphene field-effect transistors on SiC substrates

We report on a demonstration of top-gated graphene field-effect transistors(FETs) fabricated on epitaxial SiC substrate.Composite stacks,benzocyclobutene and atomic layer deposition Al2O3,are used as the gate dielectrics to maintain intrinsic carrier mobility of graphene.All graphene FETs exhibit n-type transistor characteristics and the drain current is nearly linear dependence on gate and drain voltages.Despite a low field-effect mobility of 40 cm2/(V s),a maximum cutoff frequency of 4.6 GHz and a maximum oscillation frequency of 1.5 GHz were obtained for the graphene devices with a gate length of 1 μm.     

High pulse energy femtosecond large-mode-area photonic crystal fiber laser

A high pulse energy femtosecond fiber laser based on a large-mode-area photonic crystal fiber is demonstrated. A segment of Yb-doped single-polarization large-mode-area photonic crystal fiber with extremely low nonlinearity is explored as gain media of this fiber laser, resulting in intrinsically envi- ronmentally stability. The fiber laser is based on a linear cavity with dispersion compensation free con- figuration, and the stable mode-locking is obtained by a semiconductor saturable absorber mirror （SESAM）. The fiber laser directly generates 2.5 W of average power at a repetition rate of 51.4 MHz, corresponding to a single pulse energy of 50 nJ. The output pulse duration is 4.2 ps, which is dechirped to 410 fs after extracavity dispersion compensation. The nonlinear absorption of SESAM determines the pulse shaping at low output power, while the mode-locking mechanism is under the balance between spectrum broadening from self-phase-modulation and gain filtering at the high output power.     

Enhanced conversion efficiency of Yb2＋-Yb3＋-codoped glass as spectral converter for photovoltaic application

We propose a kind of Yb2＋-Yb3＋-codoped glass, which is used as spectral converter layer to adjust AM1.5 solar spectrum for a better match with silicon bandgap. The energy-level rate equations and power transmission equations are established to analyze the down-conversional effect of the codoped glass on solar spectrum. The numerical results show that with proper doping concentration and thickness the glass layer may improve conversion efficiency by about 12 %. Moreover, we also apply the modified spectrum as excitation source of solar cell in a simulation platform, and reveal that there is about 15 % improvement in practical cells.     

Persistence in a Stochastic SEIR Model with Constant Immigration in Incubation Period

A kind of stochastic susceptible-exposed but not infectiousinfectious-removed (SEIR) model with constant immigration in incubation period is presented, based on a deterministic SEIR model, via the technique of parameter perturbation which is standard in stochastic population modeling. The influence of the environmental noise as a standard Gaussian white noise on the epidemics' transmission is studied. Furthermore,the condition for the epidemics' persistence is obtained by formulating the corresponding function and using It 's formula. And the asymptotic behavior of the model near the endemic disease equilibrium is also studied. In this way, the decision support is provided in the application of this kind of stochastic SEIR model on the epidemics' prevention and control.     

Application of Six-Sequence Fault Components in Fault Location for Joint Parallel Transmission Line

A new fault location method based on six-sequence fault components was developed for parallel lines based on the fault analysis of a joint parallel transmission line. In the six-sequence fault network, the ratio of the root-mean square value of the fault current from two terminals is the function of the line impedance, the system impedance, and the fault distance away from the buses. A fault location equation is given to relate these factors. For extremely long transmission lines, the distributed capacitance is divided by the fault point and allocated to the two terminals of the transmission line in a lumped parameter to eliminate the influence of the distributed capacitance on the location accuracy. There is no limit on fault type and synchronization of the sampling data. Simulation results show that the location accuracy is high with an average error about 2%, and it is not influenced by factors such as the load current, the operating mode of the power system, or the fault resistance.     

Multipolar model for collisional quantum interference on rotational energy transfer

A theoretical model of collisional quantum interference ( CQI) is developed in a diatom-diatom system based on the first-order Born approximation of time-dependent perturbation theory and the multipolar interaction potential. The transition cross section is obtained. The relations between the differential and integral interference angles are discussed. The key factors on the determination of the differential and integral interference angles are obtained. The changing tendency of the interference angles with the experimental temperatures is obtained.     

Intelligent Control on Hot Strip Coiling Temperature

A new intelligent control scheme for hot strip coiling temperature is presented. In this scheme, the prediction model of finishing temperature and the presetting model of main cooling zone are establish based on BP neural network, the feed-forward open-loop control model of main cooling zone is constructed based on T-S fuzzy neural network, a new improved structure of T-S fuzzy neural network is developed, and the feedback close-loop control model of precision cooling zone is obtained based on fuzzy control. The effectiveness of the proposed scheme has been demonstrated by computer simulation with a satisfactory result.     

A model for assessing effects of climate change on runoff in China

A model is established for assessing the effects of climate change on runoff in China based on the land surface parameterization scheme variable infiltration capacity (VIC). The entire area of China is represented by 2604 cells with a resolution of 60 km×60 km for each cell. Forcing data, soil and vegetation parameters needed by the VIC model for the entire area of China are prepared. Daily forcing data, which are obtained from 740 stations between 1980 and 1990, are interpolated to the 60 km×60 km grid system. The VIC model is run on every grid cell over the whole China, and a routing scheme is run offline with daily input of surface runoff and drainage from the VIC to get hydrograph at basin outlets. The spatial patterns of simulated runoff and mean annual precipitation are consistent very well. The results of monthly streamflow simulations over the Huaihe and Weihe River basins indicate that there is a good agreement between the observed and simulated values, and also initially indicate the rationality and feasibility of the evaluation model.     

An electrical-filtered optical heterodyne technique for tuning speed measurement of DBR lasers

A new scheme based on the electrical-filtered optical heterodyne technique is proposed for measuring the tuning speed of tunable distributed Bragg reflector (DBR) lasers. In this scheme, a 10 GHz high-pass electrical filter is used and the wavelength switching time of a tunable DBR laser for different tuning frequencies corresponding exactly to different delay lines is measured. The switching time is measured to be nearly 300 ns and can be improved by reducing the equivalent resistance-capacitance (RC) time constant of the device. The distribution of the beat signal of the DBR laser in the time domain is also obtained, and is a good match with the waveforms measured using an optical filter.     

Multipliers on weighted Hardy spaces over locally compact Vilenkin groups

A weighted Hpω(G) multiplier theorem on the multiplier operator T associated with a function m∈ L∞ (Γ) is shown and the atomic decomposition of functions fin Hp*(G) is obtained, where G is a Vilenkin group, r its dual, 0 < p≤1 and ω is a weight on G which is more general than that proposed by C. W. Onneweer et al.     

Global Asymptotic Stability of Neural Networks with Time Delay

The global asymptotic stability problem of Cellular neural networks with delay is investigated.A new stability condition is presented based on Lyapunov-Krasovskii method,which is dependent on the size of delay.The result is given in the form of LMI,and the admitted upper bound of the delay can be obtained easily.The time delay dependent and independent results can be obtained,which include some results in the former literature.Finally,a numerical example is given to illustrate the effectiveness of the main results.     

Spatial separation of spectrum inside the tapered metamaterial optical waveguide

In this work,the optical metamaterials based on silver dendritic cells are prepared by electrochemical deposition,and its transmission and focusing behaviors are investigated.The experimental results show that the optical metamaterials reveal a multiple pass-band transmission spectrum and a prominent focusing effect at the wavelength corresponding to the maximum transmission coefficient.Two optical metamaterial samples are combined into a tapered optical waveguide,and the spectra of transmitted light at the surface of the tapered optical waveguide is measured by using the fiber spectrometer along the light propagation direction.The results demonstrate that each frequency component of the wave packet is stopped at a different waveguide thickness,leading to the spatial separation of its spectrum.The spatial separation of spectrum can be effectively tuned by adjusting the inclination of the tapered optical waveguide,which can be used for storing photons and slow-light research.     

Performance of a 60 F carbon nanotubes-based supercapacitor for hybrid power sources

A supercapacitor based on charge storage at the interface between a high surface area carbon nanotube electrode and a LiClO₄/PC electrolyte was assembled. The performance of the capacitor depends on not only the material used in the cell but also the construction of the cell. From a constant charge-discharge test, the capacitance of 60 F was obtained. The performance of the power capacitor for pulse power sources was described. The specific energy (0.8 W·h·kg-1) and the specific power (0.75 kW·kg-1) of the power supercapacitor were demonstrated with a cell of the maximum operating voltage of 2.5 V. A hybrid power source consisting of a lithium ionic battery and the 60 F supercapacitor was demonstrated to power successfully a simulated power load encountered in GSM portable communication equipment. The addition of the supercapacitor to the power train of a cellular phone results in significantly more energy from the battery being used by the load. The experiments indicate that more than 33.8% energy is utilized by load and less stored energy is dissipated within the battery for each charge-discharge cycle.     

Study on ceramic photonic bandgap structure with three-dimensional diamond lattice

A novel process,which was based on powder injection molding,was investigated for the fabrication of ceramic photonic bandgap structure with three-dimensional diamond lattice. The SiO₂-TiO₂ ceramic powder was mixed with a water-soluble agent to produce slurry. The slurry was then injected into an epoxy mold with inverse diamond lattice,fabricated by the stereolitographic rapid prototyping process. To increase the density of the green compact,cold isostatic pressing was applied on the unit. Using thermal de-binding,the water-soluble agent and the epoxy were extracted at 360 and 650 K,respectively. Sintering was immediately done at 950 K for 5 h and the desired three-dimensional ceramic structure was obtained. The calculated band diagram for this structure indicated the existence of an absolute photonic bandgap for all wave vectors. At 14.7-18.5 GHz,a complete band gap was located with a maximum attenuation of 30 dB at 17 GHz,when transmission was measured in the <100> direction between 10 and 20 GHz.     

Event-driven Dynamic and Intelligent Scheduling for Agile Manufacturing Based on Immune Mechanism and Expert System

Based on the biological immune concept, immune response mechanism and expert system, a dynamic and intelligent scheduling model toward the disturbance of the production such as machine fault, task insert and cancel etc. is proposed. The antibody generation method based on the sequence constraints and the coding rule of antibody for the machining procedure is also presented. Using the heuristic antibody generation method based on the physiology immune mechanism, the validity of the scheduling optimization is improved, and based on the immune and expert system under the event-driven constraints, not only Job-shop scheduling problem with multi-objective can be solved, but also the disturbance of the production be handled rapidly. A case of the job-shop scheduling is studied and dynamic optimal solutions with multi-objective function for agile manufacturing are obtained in this paper. And the event-driven dynamic rescheduling result is compared with right-shift rescheduling and total rescheduling.     

A 5.3-GHz 32-bit accumulator designed for direct digital frequency synthesizer

A 32-bit pipeline accumulator with carry ripple topology is implemented for direct digital frequency synthesizer.To increase the throughout while hold down the area and power consumption,a method to reduce the number of the pre-skewing registers is proposed.The number is reduced to 29% of a conventional pipeline accumulator.The propagation delay versus bias current of the adder circuit with different size transistors is investigated.We analyze the delay by employing the open circuit time constant method.Compared to the simulation results,the maximum error is less than 8%.A method to optimum the design of the adder based on the propagation delay is discussed.The clock traces for the 32-bit adder are heavily loaded,as there are 40 registers being connected to them.Moreover,the differential clock traces,which are much longer than the critical length,should be treated as transmission lines.Thus a clock distribution method and a termination scheme are proposed to get high quality and low skew clock signals.A multiple-type termination scheme is proposed to match the transmission line impedance.The 32-bit accumulator was measured to work functionally at 5.3 GHz.     

A thermal insulation method for a piezoelectric transducer

This study deals with the sources of signal distortion of a piezoelectric transducer heated by measured gas flow. These signal distortions originate from both unloading of preload on a piezocrystal because of expansion of a diaphragm in the test apparatus and the pyroelectric effect of a heated piezoelectric crystal. A plastic film on the diaphragm of the transducer can effectively insulate the diaphragm and the piezocrystal within transducer from heating by gas flow, eliminating the sources of distortion. A method for evaluating the thickness of the film is proposed.