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Based on the study of microcavity-taper coupling system,the impacts of the coupling distance from the exterior vibration noise is introduced,and the relation between the coupling distance and the coupling state is analyzed systematically.To further validate the stability of the system and to avoid the disruption from the exterior vibration noise,two methods are taken to suppress the effect specially.One is to cover the coupling system with a designed isolation mantle.The other one is to package the tapered fiber with the microcavity into an entire body by using the UV mucus.The experimental results show that both the two methods are feasible and can make the system stable.Especially in the second scheme,the integrated microsphere-taper system is completely isolated from the outside,and it will not be interfered by the exterior vibration noise.This structure paves the way for the follow-up experiment.

Bipolar junction transistors (BJTs) are generally employed in spacecraft, due to their current drive capability, linearity and excellent matching characteristics. High-energy particles and cosmic rays in space environment remarkably affect electronic devices, especially in BJTs producing total ionizing dose, displacement damage or single event effect. Among them, ionizing irradiation effects on BJTs dominates. For BJTs, ionization damage can induce the oxide trapped charges in SiO2 layer and interface traps in Si/SiO2, resulting in more recombination base current and the degradation of current gain. Consequently, the accumulation of both oxide charges and interface traps causes an increase in the base current.#br#Passivation layer is also an important factor of the irradiation effects of BJTs. Previous works only studied the degradation of electrical properties of the devices with/without passivation layer induced by irradiation, and did not give an influence mechanisms of passivation layer on the irradiation respond of devices. Therefore, the irradiation damage mechanisms of the BJTs with or without nitride passivation layer are not clear so far.#br#In this paper, the impact of Si3N4 passivation layer on ionizing irradiation damage on lateral PNP bipolar transistors (LPNP) was studied by using 60Co gamma irradiation source. The KEITHLEY 4200-SCS semiconductor parameter analyzer was used to measure the relationship between the electrical properties of LPNP transistors and ionization dose, including the Gummel characteristics, the degradation of current gain, etc. The irradiation defects of the LPNP transistors with/without passivation layer structure were analyzed by the deep level transient spectroscopy (DLTS). The experimental results show that the electrical properties of the LPNP transistors with and without passivation layer exhibit similar characteristics. For all samples, the base current increases with increasing the total dose, while the collector current does not almost change. Compared with the LPNP transistors without Si3N4 passivation layer, the degradation of LPNP transistor with Si3N4 passivation layer is severe.#br#Based on the excess base current as a function of base-emitter voltage for the LPNP transistors with/without nitride passivation layer, the degradation of bipolar transistors with nitride passivation layer is severe under the same irradiation conditions. The DLTS analyses show that compared with the bipolar transistors without nitride passivation layer, the signal peak located at about 300 K is shifted to low temperature for the bipolar transistors with nitride passivation layer. The above results show that the LPNP transistors with nitride passivation could produce a large number of interface states with the energy level is closer to the middle of the forbidden band during the irradiation, which is attributed to a large number of hydrogen presence during the processing of fabricated passivation layer.

Objective: to investigate the species and breeding density of acaroid mites in stored fruit-derived Chinese medicinal materials in Anhui province. Methods: samples of stored fruit-derived Chinese medicinal materials were collected from 30 herb stores and storehouses in 17 Anhui cities, where the breeding acaroids mites were detected. Results: 20 species of acaroids mites were found in 33 samples, belonging to 15 genus, 5 families of the acaridae respectively, among which T. putrescentiae, A. farinae, C. lactis, and C. berlesei are predominant species. Conclusion: stored fruit-derived Chinese medicinal materials in Anhui areas suffer from serious acaroid mites pollution. Therefore, proactive measures should be taken to control acaroid mites from breeding in an effort to reduce the harm on medicinal materials.

We investigated the current-voltage characteristic of InAs/GaAs quantum dot intermediate band solar cells (QD IBSCs) with different n-type doping density in the QD layer. The n-type doping evidently increases the open circuit voltage, meanwhile decreases the short circuit current density, and leads to the conversion efficiency approaching that of the control solar cell, that is the major role of n-type doping is to suppress the effects of QDs on the current-voltage characteristic. Our model adopts practical parameters for simulation rather than those from detailed balanced method, so that the results in our simulation are not overestimated.

Blind source separation attempts to recover unknown independent sources from a given set of observed mixtures. The two adaptive algorithms -EASI and RLS are introduced in this chapter, the separation simulation of a set of stationary signals is constructed. Through the comparative analysis, the result shows that the RLS algorithm has better convergence speed and the steady state performance than the EASI algorithm for blind signal separation of stationary signal. In the RLS algorithm, we need select appropriate forgetting factor to meet the demand of convergence speed and steady state performance.

Determination of the benchmark interest rate is the core under the marketization of the interest rate. Shibor is established for cultivating the standard rate in our country. It is essential to see whether Shibor can be the standard rate in our monetary market. In this paper, we will get solutions to this issue and make further suggestions by researching the relationship between Shibor and other market interest rates.

The stochastic resonance is investigated in the generalized Langevin equation with exponential memory kernel subjected to the joint action of internal noise, external noise and external sinusoidal forcing. The system is converted into three-dimensional Markovian Langevin equations. Furthermore, using the Shapiro-Loginov formula and the Laplace transformation technique, the exact expressions of the first moment and the steady response amplitude are obtained. The research results show that with the variations of external sinusoidal force frequency and the parameters of memory kernel and external noise, the system presents bona-fide stochastic resonance, conventional stochastic resonance and stochastic resonance in a broad sense under the condition of Routh-Hurwitz stability. In addition, the stochastic resonance can be weakened as the memory time increases. Moreover, the numerical results of power spectrum of system are in agreement with the analytic results.

In this paper, second-moments of the responses are analytically solved by the Laplace transform in a coupling two-degree-of-freedom system with a biexponentical dissipative memory kernel function driven by a thermal broadband noise. The mean square displacement x2(t)> is different from anomalous diffusion (i.e. x2(t)> ∝ tα (0αα≠1)), which is produced by the single-degree-of-freedom generalized Langevin equation. The oscillation-diffusion of x2(t)> with the change of time and noise parameters is observed generally. According to our analysis, a particle confined by the harmonic potential can escape with the help of the coupling-damping factor B. The diffusion of x2(t)> aggravates with B increasing. However, x2(t)> tends to the stationary state with the increase of the friction coefficient Further, if the two thermal noises are in cross-correlation, smaller cross-correlation time has a deeper influence on second-moments. Meanwhile, the diffusion aggravates and the cross-correlation between two displacements strengthens markedly with cross-correlation strength increasing. It is consistent with physical intuition.

We demonstrate a technique of temperature compensation for 1.3μm InAs/GaAs quantum-dot (QD) lasers by facet coating design. The key point of the technique is to make sure that the mirror loss of the lasers decreases as the temperature rises. To realize this, we design a type of facet coating by shifting the central wavelength of the facet coating from 1310nm to 1480nm, whose reflectivity increases as the emission wavelength of the lasers red-shifts. Consequently, the laser with the new facet coating exhibits a characteristic temperature doubled in size and a more stable slope efficiency in the temperature range from 10°C to 70°C, compared with the traditional one with a temperature-independent mirror loss.

We present a systematic investigation of calculating quantum dots (QDs) energy levels using the finite element method in the frame of the eight-band k p method. Numerical results including piezoelectricity, electron and hole levels, as well as wave functions are achieved. In the calculation of energy levels, we do observe spurious solutions (SSs) no matter Burt–Foreman or symmetrized Hamiltonians are used. Different theories are used to analyse the SSs, we find that the ellipticity theory can give a better explanation for the origin of SSs and symmetrized Hamiltonian is easier to lead to SSs. The energy levels simulated with the two Hamiltonians are compared to each other after eliminating SSs, different Hamiltonians cause a larger difference on electron energy levels than that on hole energy levels and this difference decreases with the increase of QD size.

We demonstrate 10 Gb/s directly-modulated 1.3 μm InAs quantum-dot (QD) lasers grown on GaAs substrates by molecular beam epitaxy. The active region of the QD lasers consists of five-stacked InAs QD layers. Ridge-waveguide lasers with a ridge width of 4 μm and a cavity length of 600 μm are fabricated with standard lithography and wet etching techniques. It is found that the lasers emit at 1293 nm with a very low threshold current of 5 mA at room temperature. Furthermore, clear eye-opening patterns under 10 Gb/s modulation rate at temperatures of up to 50° C are achieved by the QD lasers. The results presented here have important implications for realizing low-cost, low-power-consumption, and high-speed light sources for next-generation communication systems.

We report the molecular beam epitaxy growth of 1.3 mu m InAs/GaAs quantum-dot (QD) lasers with high characteristic temperature T-0. The active region of the lasers consists of five-layer InAs QDs with p-type modulation doping. Devices with a stripe width of 4 mu m and a cavity length of 1200 mu m are fabricated and tested in the pulsed regime under different temperatures. It is found that T-0 of the QD lasers is as high as 532K in the temperature range from 10 degrees C to 60 degrees C. In addition, the aging test for the lasers under continuous wave operation at 100 degrees C for 72 h shows almost no degradation, indicating the high crystal quality of the devices.