Parameter determination from current–voltage characteristics of HgCdTe photodiodes in forward bias region

Current–voltage characteristics of HgCdTe photodiodes in the forward bias region have been modeled considering mechanisms including drift-diffusion current, recombination current, metal-semiconductor contact and constant series resistance. Moreover, a fitting method based on the genetic algorithm has been developed to obtain values of related physical parameters from the measured dynamic resistance–voltage curves. Fitting results of $n^+$ -on- $p$ planar devices with different cutoff wavelengths are presented to illustrate the model and method, which are available and promising in acquiring device parameter values and evaluating the electrode contact quality.     

Label-free high-throughput and real-time detections of protein interactions by oblique-incidence reflectivity difference method

Selected Mouse IgG of 1 mg/mL as target was fabricated on microarray for 500 sample dots.Label-free and real-time reaction dynamic processes were detected between the microarrays with Goat Anti-mouse IgG of 0.02 mg/mL using the obliqueincidence reflectivity difference(OIRD)method.We obtained the reaction results and the reaction dynamic curves of 500 protein dots.In addition,we also used label-free detection of protein microarrays of 10080 sample dots,including BSA and different concentrations of Mouse IgG and Rabbit IgG,by OIRD.The obtained reaction results between the protein microarray with 1 mg/mL Goat Anti-mouse IgG and 1 mg/mL Goat Anti-rabbit IgG are reported herein.Experimental results show that OIRD can be not only label-free high-throughput detection method for biological microarrays but also label-free real-time detection in the interaction processes of biomolecules.     

The solution of the characteristic equation of circular-rectangular groove guide

Circular-rectangular groove guide is a new type of structure we have presented for coupling between circular groove guide and rectangular groove guide. In this paper, as the continuity of our previous work, the characteristic equation of circular-rectangular groove guide has been solved and the numerical results have been given and discussed.The Project Supported by National Natural Science Foundation of P. R. China     

Second-harmonic generation in thermally poled chalcohalide glass

Second-harmonic generation in 60GeS(2)-20Ga(2)S(3)-20KBr chalcohalide glass was investigated by the thermal poling method. A large second-order nonlinear susceptibility, as high as 7.0 pm/V, was obtained in a poled sample by Maker fringe analysis. We believe this to be the first time that a clear second-harmonic wave was observed in chalcohalide glasses containing large amount of alkali ions (6.25 at. %). Such observation is of great potential use in all optical waveguide devices.     

Observation of upconversion fluorescence and stimulated emission based on three-photon absorption

The observations of three-photon-induced frequency-upconversion fluorescence and the highly directional stimulated visible emission in two dyes, 4-[p-(dicyanoethylamino) styryl]-N-methylpyridinium iodide (abbreviated as CEASP) and the complex of CEASP and Ce(NO₃) (abbreviated as CEASP-Ce), are reported. The photographs of the forward amplified spontaneous emissions spots, pumped by an optical parametric oscillator idler with a pulse width of 8 ns and a wavelength of 1.3 μ m, are shown. The upconversion fluorescence produced both in dimethyl formamide solution and 2-hydroxyethyl methacrylate (HEMA) polymer spans from green to red, with a cubic dependence on the pump light intensity. The experimental results imply that the existence of the lanthanide ion Ce^{3 +} sensitizes the nonlinear absorption and emission.     

The Modeling Library of Eavesdropping Methods in Quantum Cryptography Protocols by Model Checking

The most crucial issue of quantum cryptography protocols is its security. There exists many ways to attack the quantum communication process. In this paper, we present a model checking method for modeling the eavesdropping in quantum information protocols. So when the security properties of a certain protocol are needed to be verified, we can directly use the models which are already built. Here we adopt the probabilistic model checking tool—PRISM to model these attack methods. The verification results show that the detection rate of eavesdropping is approximately close to 1 when enough photons are transmitted.     

Vibration of vehicle–pavement coupled system based on a Timoshenko beam on a nonlinear foundation

This paper focuses on the coupled nonlinear vibration of vehicle–pavement system. The pavement is modeled as a Timoshenko beam resting on a six-parameter foundation. The vehicle is simplified as a spring–mass–damper oscillator. For the first time, the dynamic response of vehicle–pavement coupled system is studied by modeling the pavement as a Timoshenko beam resting on a nonlinear foundation. Consequently, the shear effects and the rotational inertia of the pavement are included in the modeling process. The pavement model is assumed to be a linear-plus-cubic Pasternak-type foundation. Furthermore, the convergent Galerkin truncation is used to obtain approximate solutions to the coupled vibratory response of the vehicle–pavement coupled system. The dynamic responses of the vehicle–pavement system with the asphalt pavement on soft soil foundation are investigated via the numerical examples. The numerical results show that the calculation for the coupled vibratory response needs high-order modes. Moreover, the coupling effects between the pavement and the vehicle are numerically examined by using the convergent modal truncation. The physical parameters of the vehicle–pavement system such as the shear modulus are compared for determining their influences on the coupled vibratory response.     

An occlusion-adaptive tracker based on sparse representation using alternating direction method of multipliers

Recently, sparse representation has been applied to visual tracking with satisfactory performance. However, partial occlusion and computational complexity are two main obstructions in developing sparse-based tracking. In this paper, a simple yet robust tracker based on patch-based sparse representation is proposed. An adaptive motion model, including adaptive sampling regions and adaptive particle numbers, is proposed to improve the sampling efficiency. A self-adjustable segmentation approach is proposed to segment the target into local patches. A patch-based observation model, which is occlusion-adaptive, is constructed by solving a set of L1-regularized least squares problems. The L1-regularized least squares problem is solved using the alternating direction method of multipliers (ADMM). Both quantitative and qualitative experiments are conducted on several challenging image sequences and the comparisons with several state-of-the-art trackers demonstrate the effectiveness and efficiency of our tracker.     

Edge and terrace structure of CoTPP on Au(1 1 1) investigated by ultra-high vacuum scanning tunnelling microscopy at room temperature

Edge adsorption and terrace molecular domain structures of Cobalt(II) tetraphenylporphyrin (CoTPP) on Au(1 1 1) were investigated using STM at room temperature. Two different terrace domain structures were observed. These two arrangements were found to be enantiomorphous arrangements of the molecular assemblies, where the molecular rows rotate ±16° with respect to the [1 2 1] direction of Au(1 1 1). In both arrangements, most of the CoTPP molecules were imaged as one bright dot with four legs, corresponding to a planar conformation of the macrocycle. A small proportion of the CoTPP molecules appear as two bright dots, corresponding to a saddle shape of the macrocycle. Our results show that most of the saddle-deformed CoTPP molecules are distributed in the vicinity of the bridging sites of the reconstructed gold surface. Besides terrace domains, we found that several edge adsorption structures of CoTPP are also stable enough to be imaged and analysed in detail. Furthermore, the relationship between edge structures and terrace domains was revealed.