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Working distance and background radiation greatly affect the signal-to-noise ratio of avalanche photodiode (APD) in the lidar detection system. The traditional method cannot adapt to a complex environment by offline compensation or pre-compensation according to the influence factors of the external environment. In this paper, an avalanche photodiode voltage compensation method based on the improved random forest is designed. Firstly, the distance image data is de-noised. Then the weight of each decision tree in the random forest was changed to improve the classification performance. The particle swarm optimization (PSO) algorithm was used to search for the optimal combination of parameters affecting classification accuracy and performance. Finally, the improved random forest algorithm is used to judge the current working state of APD at different distances, compensate for the bias voltage, and make APD work in the optimal state. The proposed method is compared with the k-nearest neighbor, support vector machine, and other commonly used classification algorithms, and the results verify the effectiveness of the proposed method.

Ion confinement technology can be widely used in quantum computation and precision measurement. In ion trapping system, ions are stably trapped in ion trap by the action of external forces.Multi-ion confinement requires the joint action of electric field and magnetic field to make the trapped ions overcome the interaction force between ions and be stably confined in the same specific space. Therefore, the stability of the electric force and the magnetic force determines the stability of ion confinement. Although the electric field and magnetic field provided by traditional commercial instruments is stable, it is not conducive to the miniaturization of the device. According to the previous experiment of ion confinement, we have designed a radio frequency(RF) signal generator that can provide continuous low power and stable high voltage RF electric field for multi-ion confinement system to guarantee the stability of trapped ions in quadrupole linear ion trap, also to improve the tapped ions density.

Recently, a Corbino-geometry type of Josephson junction constructed on the surface of topological insulators has been proposed for hosting and braiding Majorana zero modes. As a first step to test this proposal, we successfully fabricated Corbino-geometry Josephson junctions (JJs) on the surface of Bi2Te3 flakes. Ac Josephson effect with fractional Shapiro steps was observed in the Corbino-geometry JJs while the flux in the junction area was quantized. By analyzing the experimental data using the resistively shunted Josephson junction model, we found that the Corbino-geometry JJs exhibit a skewed current–phase relation due to its high transparency. The results suggest that Corbino-geometry JJs constructed on the surface of topological insulators may provide a promising platform for studying Majorana-related physics.

Geometrical frustration in low-dimensional magnetic systems has been an intriguing research aspect, where the suppression of conventional magnetic order may lead to exotic ground states such as spin glass or spin liquid. In this work we report the synthesis and magnetism study of the monocrystalline Mn2Ga2S5, featuring both the van der Waals structure and a bilayered triangular Mn lattice. Magnetic susceptibility reveals a significant antiferromagnetic interaction with a Curie–Weiss temperature θ w ∼ –260 K and a high spin S = 5/2 Mn2+ state. However, no long range magnetic order has been found down to 2 K, and a spin freezing transition is found to occur at around 12 K well below its θ w. This yields a frustration index of f = –θ w/T f ≈ 22, an indication that the system is highly frustrated. The absence of a double-peak structure in magnetic specific heat compared with the TM 2S4 compounds implies that the spin freezing behavior in Mn2Ga2S5 is a result of the competition between exchange interactions and the 2D crystalline structure. Our results suggest that the layered Mn2Ga2S5 would be an excellent candidate for investigating the physics of 2D magnetism and spin disordered state.

Introduction of spin-orbit coupling (SOC) in a Josephson junction (JJ) gives rise to unusual Josephson effects. We investigate JJs based on a newly discovered heterodimensional superlattice V$_5$S$_8$ with a special form of SOC. The unique homointerface of our JJs enables elimination of extrinsic effects due to interfaces and disorder. We observe asymmetric Fraunhofer patterns with respect to both the perpendicular magnetic field and the current. The asymmetry is influenced by an in-plane magnetic field. Analysis of the pattern points to a nontrivial spatial distribution of the Josephson current that is intrinsic to the SOC in V$_5$S$_8$., 15 pages,5 figures

Arc suppression and resonance elimination device was used more and more widely in distribution power systems. The performance for limiting overvoltage and eliminating arc are better than arc suppression coil. But when the device not work properly,it would cause more great risk on the safe of the distribution network. It was analysed that an event of power failure of pair circuits distribution network installed with arc suppression and resonance elimination device. As an example, the simulation model was established with PSCAD software, and the working mechanism of the device was discussed. The overvoltage risk of the distribution system for water supply pump station was analysed. According to the analysing results, it is proposed that routine maintenance method and typical configuration of the device.

The sparse model plays an important role in many aeras, such as in the machine learning, image processing and signal processing. The sparse model has the ability of variable selection, so they can solve the over-fitting problem. The sparse model can be introduced into the field of support vector machine in order to get classification of the labels and sparsity of the variables simultaneously. This paper summarizes various sparse support vector machines. Finally, we revealed the research directions of the sparse support vector machines in the future.

Systematic calculations of low-lying energy levels, transitions, and g factors of even-even tellurium isotopes with mass numbers from 128 to 140 are performed via the nucleon-pair approximation (NPA) of the shell model with phenomenological multipole-multipole interactions. An optimal agreement is obtained between the calculated results and experimental data. The yrast band structures of nuclei below and above the shell closure are compared and discussed. In particular, the evolutionary differences of values and factors, with respect to the symmetry of , are attributed to the dominant contribution differences in neutron and proton excitations, respectively.

A continuous-wave Nd:KGd(WO4)2 single-longitudinal-mode laser is demonstrated with Fabry–Perot etalons in a simple linear cavity. The thermal lens effect is dramatically lowered by propagating the laser beam along the ‘athermal’ direction inside the laser crystal, which is very beneficial to removing the heat generated in the mode selection process. The maximum single-longitudinal-mode output power obtained is 64.8 mW at incident pump power of 4.7 W, corresponding to an optical conversion efficiency of 1.3% and a slope efficiency of 1.7%.

To solve the problems of low accuracy and low efficiency of B-spline fitting in sunglasses lens contour cutting, a sampling method based on the characteristic function of a weighted combination of arc length and curvature square root was proposed, and then perform B-spline fitting according to the sampling points to improve the accuracy and efficiency. First, read and identify the sunglasses lens data in the DXF file, and disperse it to obtain a series of coordinate points; combine the defined feature function for uniform sampling, and adjust the parameter weight in the feature function to obtain a more reasonable sampling point for the sunglasses lens contour; Then use the LU decomposition and interpolation method to obtain the B-spline curve through all the sampling points; the maximum absolute error (MAE) and the root-mean-square error (RMSE) are used as the accuracy criteria, by increasing the number of sampling points iteratively until the accuracy is satisfied to construct a reasonable fitting curve.

It is challenging to measure the electron density of the unsteady plasma formed by charged particles generated from explosions in the air, because it is transient and on a microsecond time scale. In this study, the time-varying electron density of the plasma generated from a small cylindrical cyclotrimethylenetrinitramine (RDX) explosion in air was measured, based on the principle of microwave Rayleigh scattering. It was found that the evolution of the electron density is related to the diffusion of the detonation products. The application of the Rayleigh microwave scattering principle is an attempt to estimate the electron density in explosively generated plasma. Using the equivalent radius and length of the detonation products in the bright areas of images taken by a high-speed framing camera, the electron density was determined to be of the order of 1020 m−3. The delay time between the initiation time and the start of variation in the electron-density curve was 2.77–6.93 μs. In the time-varying Rayleigh microwave scattering signal curve of the explosively generated plasma, the electron density had two fluctuation processes. The durations of the first stage and the second stage were 11.32 μs and 19.20 μs, respectively. Both fluctuation processes increased rapidly to a peak value and then rapidly attenuated with time. This revealed the movement characteristics of the charged particles during the explosion.

To solve the current problems of waste classification and littering, this kind of BearPi-based waste bin with the functions of speech-controlled classification and locating is invented using the technologies of speech recognition and GPS. The device, with BearPi as its core element, uses solar panels and lithium batteries as power supply, IIC and serial interfaces for the respective control of PCA9685 steering gear driving board, an M5310_A communication module, ATGM332D locating module and SX-ASR-B speech recognition module, and finally, a GPIO and timer for the operation of the HC-SR04 module and an E18-D80NK photoelectric sensor. The devices could classify the waste through speech recognition or leave it for the users. Furthermore, it could detect the remaining capacity and location of the waste bins through the modules and update the cloud data for the users’ convenience in finding and using.

Under the new reform requirements, the transmission and distribution price pricing model changes, the sales side is liberalized and competition is introduced, the incremental power distribution business investment is liberalized, and the company’s permitted income is approved on the basis of effective assets. In this paper, the combination weight TOPSIS theory is used to diagnose and evaluate the physical assets of power grid companies, and the accuracy of the model is verified through analysis, and the system’s asset status diagnostic analysis and evaluation research is carried out, and the optimization strategy and evaluation calculation are scientifically proposed to provide a research and analysis basis.

The issue of campus energy and environment has become one of our increasing concerns. Environmental issues have become an important assessment index restricting the development of schools and students’ self-improvement. Only the sustainable development of the environment can ensure the smooth implementation of school education. For this reason, the development of an efficient energy environment monitoring system based on computer networks is imperative. Based on this research background, the paper analyses the needs of an efficient micro-energy environment monitoring system, and discusses the functions of the monitoring system and related hardware and software. Finally, the system was tested to verify the feasibility of the system.

With the continuous development of the automobile industry, almost every family has a car, so the car safety issue is gradually highlighted. Driving for a long time produce drowsiness; many owners simply sleep in their car, especially younger children who are more prone to the sense of fatigue. In our live, car asphyxiation accidents caused by high temperature and high concentration of carbon monoxide are very common. The automobile has been integrated into people’s life, and its related demands are more diversified. The automobile industry is about to enter the “post-automobile era”. The problem of the interior safety of automobiles is what we need to solve urgently. It is an important means for people to know the safety problems inside the car correctly and take precautions against them. In this document, the status quo of the automotive interior safety problems are described and analyzed. Based on the actual situation, a sensor-based automotive interior safety alarm system is proposed to promote the development of automobile safety industry.

Chalcopyrite was synthesized with various reaction precursors and solvents, and plate-, rod-, and sphere-like chalcopyrite can be obtained. Our results show that rod-like chalcopyrite has higher discharge capacity, better rate capacity and cycle performance than others.

The electric quadrupole moment and the magnetic moment (or the factor) of low-lying states in even-even nuclei 72-80Ge and odd-mass nuclei 75-79Ge are studied in the framework of the nucleon pair approximation (NPA) of the shell model, assuming the monopole and quadrupole pairing plus quadrupole-quadrupole interaction. Our calculations reproduce well the experimental values of and for 72,74,76Ge, as well as the yrast energy levels of these isotopes. The structure of the states and the contributions of the proton and neutron components in and are discussed in the -pair truncated shell-model subspace. The overall trend of and as a function of the mass number , as well as their signs, are found to originate essentially from the proton contribution. The negative value of in 72,74Ge is suggested to be due to the enhanced quadrupole-quadrupole correlation and configuration mixing.

Styrene-terminated polyphenylene oxide (SPPO) and low polar thermosetting polybutadiene (PB) resin were employed to obtain a curing system with excellent electrical properties and enhanced thermal properties. By terminal styrenisation, SPPO is cured with PB, forming a continuous phase in the blend. The SPPO/PB blends have excellent solvent resistance and thermal stability, while the good dielectric performance is retained. Especially, when the mass ratio of PB is 0.5, the curing system has a high T g of 226.5°C and excellent dielectric properties with Dk = 2.46 and Df = 0.0022 at 10 GHz, which is suitable for high frequency electrical applications.

A new type of doubly salient permanent magnet machine with a dual stator structure is proposed. The motor is designed by staggering two stators by 45°on a 4/6 pole structure of double-salient pole motor. The motor has the advantages of high power density, small pulsation and high efficiency. The basic structure and working principle of the motor are introduced. The air-gap flux is calculated by the simple magnetic circuit method. The no-load magnetic field distribution, air gap flux density and permanent magnet Flux, back EMF, inductance characteristics of the machine are analyzed by using finite element simulation software. The inherent cogging torque of permanent magnet machine is analyzed. The simulation results verify the rationality of the new structure machine.

In this paper, an experimental study of collinear geometry double-pulse femtosecond LIBS was performed on a Ni sample in ambient air in an effort to clarify the contributing processes responsible for the signal enhancement observed in comparison with the single-pulse case. Double-pulse LIBS spectra show a very clear enhancement when an optimum inter-pulse delay was used. The influences of the inter-pulse delay between two pulses on the LIBS signal intensity, electron temperature and density were investigated. It is most remarkable that the evolutions of signal enhancement and electron temperature versus the inter-pulse delay showed the same behavior and revealed two main regimes of interaction. These results provide additional insight into the possible emission enhancement mechanisms in the double pulse configuration.

By utilization of different excitation power sources, linear plasma sources can be differentiated into DC, RF, VHF, microwave and dual frequency types. Through installing several linear plasma sources in parallel or adopting the so-called roll-to-roll (air-to-air) process, scale uniform linear plasma sources were realized and successfully applied to the deposition of large area uniform dielectric thin films. Furthermore, the magnetic field system can effectively reduce the recombination losses on the wall of the vacuum chamber and enhance the plasma density. Linear plasma sources with approximately one square meter deposition area with the plasma density of 1011 cm−3 have been developed, some of which have been used for the deposition of dielectric layers and large area plasma etching.

A typical quinolones antibiotic ciprofloxacin (CIP) in aqueous solution was degraded by a gas-liquid discharge non-thermal plasma system. The discharge plasma power and the emission intensity of the excited reactive species (RS) generated in the gas phase were detected by the oscilloscope and the optical emission spectroscopy. The effects of various parameters on CIP degradation, i.e. input powers, initial concentrations addition of radical scavengers and pH values were investigated. With the increase of discharge power, the degradation efficiency increased but the energy efficiency significantly reduced. The degradation efficiency also reduced under high concentration of initial CIP conditions due to the competitive reactions between the plasma-induced RS with the degradation intermediates of CIP. Different radical scavengers (isopropanol and CCl4) on center dot OH and H center dot were added into the reaction system and the oxidation effects of center dot OH radicals have been proved with high degradation capacity on CIP. Moreover, the long-term degradation effect on CIP in the plasma-treated aqueous solution proved that the long-lived RS (H2O2 and O-3, etc) might play key roles on the stay effect through multiple aqueous reactions leading to production of center dot OH. The degradation intermediates were determined by the method of electrospray ionization (+)-mass spectroscopy, and the possible degradation mechanism were presented.

A radio frequency argon plasma reactor with a stirrer was employed for the surface treatment of polypropylene (PP) powders. The changes in the superficial contact angle and the superficial composition of the un-treated and treated PP powders were analyzed by means of water contact angle (WCA) measurement, X-ray photoelectron spectroscopy (XPS) and attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR). The water contact angle changed from the original value of 130.2° before plasma treatment to the value of 73.6° after treatment for 5 minutes. With the increase in plasma treating time, there were a decrease in the water contact angle and an increase in the content of oxygen containing polar functional groups (i.e., C-O, C=O and O-C=O). Both XPS and ATR-FTIR results indicated that the plasma treatment led to the formation of oxygen containing polar functional groups due to oxidation on the surface of the PP powders, and the trend of variation of the water contact angle with plasma treating time was related to the concentration of oxygen atom on the treated PP powders surface. Furthermore, the aging of the plasma-treated PP powders was investigated.

This paper explores the intra-layer synchronization in duplex networks with different topologies within layers and different inner coupling patterns between, within, and across layers. Based on the Lyapunov stability method, we prove theoretically that the duplex network can achieve intra-layer synchronization under some appropriate conditions, and give the thresholds of coupling strength within layers for different types of inner coupling matrices across layers. Interestingly, for a certain class of coupling matrices across layers, it needs larger coupling strength within layers to ensure the intra-layer synchronization when the coupling strength across layers become larger, intuitively opposing the fact that the intra-layer synchronization is seemly independent of the coupling strength across layers. Finally, numerical simulations further verify the theoretical results.

TiO2/C/Fe3O4 magnetic composite catalyst was prepared by using glucose as carbon source to attach an intermediate isolation layer and then wrapping TiO2 directly on Fe3O4 magnetic support. The catalytic performance of the catalyst was studied by photodegradating RhB simulated wastewater under the changed external conditions such as light resource, temperature, pH and ion intensity of the solution. It was found that the photocatalytic performance under uv light was better than that of the catalyst under the visible light. The photocatalytic performance increased with the increase of temperature and acidity of the wastewater, and the decrease of the ion intensity of the wastewater. The optimum photocatalytic reaction condition was under uv light, the temperature was 75°C, pH was 1 and ion intensity was 1mmol/L. The magnetic effect was applied to the reutilization of the catalyst, and the fourth recycled catalyst still had catalytic activity, but with the increase of reusing time, the photocatalytic performance of the catalyst decreased gradually. The photodegradation rate of the recycled catalyst 90 min later was reduced from 76.20% to 57.08%, 41.80%, 28.44%, respectively, while 4 times of repeated use under uv light, 25°C, pH 1, and ion intensity 1 mmol/L.

In this research, an atmospheric-pressure air plasma is used to inactivate the multidrug-resistant Acinetobacter baumannii in liquid. The efficacy of the air plasma on bacterial deactivation and the cytobiological variations after the plasma treatment are investigated. According to colony forming units, nearly all the bacteria (6-log) are inactivated after 10 min of air plasma treatment. However, 7% of the bacteria enter a viable but non-culturable state detected by the resazurin based assay during the same period of plasma exposure. Meanwhile, 86% of the bacteria lose their membrane integrity in the light of SYTO 9/PI staining assay. The morphological changes in the cells are examined by scanning electron microscopy and bacteria with morphological changes are rare after plasma exposure in the liquid. The concentrations of the long-living RS, such as H2O2, and O3, in liquid induced by plasma treatment are measured, and they increase with plasma treatment time. The changes of the intracellular ROS may be related to cell death, which may be attributed to oxidative stress and other damage effects induced by RS plasma generated in liquid. The rapid and effective bacteria inactivation may stem from the RS in the liquid generated by plasma and air plasmas may become a valuable therapy in the treatment of infected wounds.

Atmospheric pressure helium/water dielectric barrier discharge (DBD) plasma is used to investigate the generation of reactive species in a gas–liquid interface and in a liquid. The emission intensity of the reactive species is measured by optical emission spectroscopy (OES) with different discharge powers at the gas–liquid interface. Spectrophotometry is used to analyze the reactive species induced by the plasma in the liquid. The concentration of OH radicals reaches 2.2 μm after 3 min of discharge treatment. In addition, the concentration of primary long-lived reactive species such as H2O2, and O3 are measured based on plasma treatment time. After 5 min of discharge treatment, the concentration of H2O2, , and O3 increased from 0 mg L−1 to 96 mg L−1, 19.5 mg L−1, and 3.5 mg L−1, respectively. The water treated by plasma still contained a considerable concentration of reactive species after 6 h of storage. The results will contribute to optimizing the DBD plasma system for biological decontamination.

We studied the morphological evolution during spinodal phase separation and subsequent coarsening in systems with a strong dependence of elastic constants on the composition. An efficient numerical method is developed for solving the two-dimensional inhomogeneous elastic equilibrium equations by using the conjugate gradient method. A simple model binary system with a symmetric miscibility gap is considered. It is shown that the early stages of spinodal phase separation in a solid solution with a 50-50% composition always result in an interconnected morphology, regardless of the degree of elastic inhomogeneity. For systems with strong elastic inhomogeneity, particle splitting and coalescence take place concurrently during coarsening. In the late stages, the morphology has the characteristics that the hard phase forms precipitates surrounded by the soft phase which forms the matrix, similar to that predicted previously by others using first-order approximations. An analysis of the coarsening kinetics shows that although the growth exponent decreases with the increase in the degree of elastic inhomogeneity, there is no freezing of the coarsening kinetics for all the cases that we studied, in contrast to that predicted previously by others. The effect of an externally applied strain on the two-phase morphology in the elastic regime is also discussed.

Recent experiments of Weisberg et al. (1997. J. Fluid Mech. 348, 141{151) have demonstrated that the onset of the centrifugal instability leading to Taylor vortex ow can be delayed by harmonic oscillations of the inner cylinder in the axial direction. Marques and Lopez (1997. J. Fluid Mech. 348, 153{175) used Floquet analysis to describe the observed control of the instability over a wide range of frequencies and amplitudes of this oscillation; the dynamics remained axisymmetric and the response to the applied periodic control mechanism was synchronous over an extensive range of parameters. Here we implement an accurate and ecient spectral-projection scheme for solving the fully nonlinear axisymmetric Navier{Stokes equations to examine the eects of endwalls on the ow dynamics and the breaking of space-time symmetries. By varying a single parameter we have detected a route to chaos. As the parameter is increased the system undergoes a quasiperiodic Naimark{Sacker bifurcation, goes through a 1:9 resonance horn (Arnold’s tongue), and then chaos. c 2000 The Japan Society of Fluid Mechanics and Elsevier Science B.V. All rights reserved.

Reversible resistance switching behavior was observed in a simple proto-type non-volatile memory cell using GeTi thin film. The film prepared by magnetic sputtering at room temperature was amorphous. The reversible switching phenomenon appeared when applying a property external bias voltage on the cell. The ratio of the high resistance state (off-state) to the low resistance state (on-state) was 10–102. Because of the electric-pulse-induced resistance switching property of GeTi and its simple binary constitution compatible with the semiconductor industry, the application prospect of GeTi as a storage medium for data recording can be predicted.

An actively mode-locked Ho:YAG laser pumped by a diode-pumped Tm-doped fiber laser is reported. For the cw operation, we obtain the maximum output power of 3.43 W with a central wavelength 2022.2 nm at the maximum incident pump power of 11.4 W, corresponding to a slope efficiency of 34.5%. The beam quality factor M2 is 1.16, and the output beam is close to fundamental TEM00. In the case of the CWML operation, a stable pulse train is generated with an average output power up to 3.41 W with a slope efficiency of 34.3% at the incident pump power of 11.4 W and a pulse duration of 294 ps at a repetition rate of 81.92 MHz. In addition, the maximum single pulse energy is 41.6 nJ.

The homotopy analysis method (HAM) is introduced to solve the generalized Boussinesq equation. In this work, we establish the new analytical solution of the exponential function form. Applying the homotopy perturbation method to solve the variable coefficient Boussinesq equation. The results indicate that this method is efficient for the nonlinear models with variable coefficients.

A preliminary study has been carried out to evaluate the possibility of patterning biological molecules on surfaces for scanning tunnelling microscopy and atomic force microscopy. The approach uses the concept of treating surfaces that are suitable for semiconductor lithography with bridging molecules that can be patterned to micrometre and nanometre scales. Indium tin oxide and flame-treated gold have been selected as the immobilization surfaces, and initial results indicate good anchorage of proteins for scanning tunnelling microscope imaging using the bridging procedure developed.

We demonstrate a mid-IR ZnGeP2 (ZGP) optical parametric oscillator (OPO) pumped by a dual-end-pumped actively acousto-optic Q-switched Ho:YAG ceramic laser. The maximum average output power of 35 W is obtained at a pulse repetition frequency of 20kHz from the Ho:YAG ceramic laser. Under the maximum incident pump power of Ho:YAG ceramic laser, the maximum output power of 14 W is obtained from the ZGP OPO, corresponding to the slope efficiency of 49.6% with respect to the incident pump power. The wavelength can be tuned from 3.5 μm to 4.2 μm (signal), corresponding to 5.2–4.1 μm (idler). The beam quality M2 is less than 2.3 from the ZGP OPO.

We demonstrate a high power Ho:YAG ceramic laser resonantly pumped by a Tm:YLF laser at 1908 nm. The lasing characteristics of a 1.0 at.% Ho3+-doped YAG ceramic are investigated and compared with different output couplers. By using an output coupler of 50% transmission and 100 mm radius of curvature, a 26.8 W continuous wave is obtained at 2091 nm, corresponding to a slope efficiency of 57.9% and an optical to optical efficiency of 55.8% with respect to the absorbed pump power.

InGaAs quantum dots (QDs) on GaP are promising for monolithic integration of optoelectronics with Si technology. To understand and improve the optical properties of InGaAs/GaP QD systems, detailed measurements of the QD atomic structure as well as the spatial distributions of each element at high resolution are crucial. This is because the QD band structure, band alignment, and optical properties are determined by the atomic structure and elemental composition. Here, we directly measure the inhomogeneous distributions of In and As in InGaAs QDs grown on GaAs and GaP substrates at the nanoscale using energy dispersive x-ray spectral mapping in a scanning transmission electron microscope. We find that the In distribution is broader on GaP than on GaAs, and as a result, the QDs appear to be In-poor using a GaP matrix. Our findings challenge some of the assumptions made for the concentrations and distributions of In within InGaAs/GaAs or InGaAs/GaP QD systems and provide detailed structural and elemental information to modify the current band structure understanding. In particular, the findings of In deficiency and inhomogeneous distribution in InGaAs/GaP QD systems help to explain photoluminescence spectral differences between InGaAs/GaAs and InGaAs/GaP QD systems.

The inactivation of Bacillus subtilis spores by an Ar plasma jet mixed with different amounts of oxygen is reported. 5.8 × 106 B. subtilis spores are sterilized by an Ar/O2 (8.7%) plasma jet after exposure for 2 min. The densities of ozone and oxygen radicals in the Ar/O2 plasma jet increase with oxygen concentration and are estimated by optical spectroscopy diagnostic. The malondialdehyde (MDA) test shows that oxygen radicals participate in bacterial inactivation. Scanning electron microscopy (SEM) reveals the deformation of the spore shape due to etching by oxygen radicals and the dependence of the degree of deformation on the density of oxygen radicals.

A 2.09-μm in-band pumped passively Q-switched Ho:YAG laser is demonstrated. Single layer graphene deposited on a quartz substrate is used as the saturable absorber for the Q-switched operation. The minimum pulse width of 2.11 μs is obtained at an average output power of 100 mW, corresponding to a pulse repetition frequency of 57.1 kHz and the pulse energy of 1.75 μJ. The beam quality factors M2 of the Q-switched laser are 1.18 and 1.22 in the horizontal and longitudinal direction, respectively. The optical-to-optical conversion efficiency of the passively Q-switched laser is 4.3%, which is the highest conversion efficiency in the 2 μm wavelength, to the best of our knowledge. It shows clearly that the Ho:YAG crystal is a potential gain medium in the 2 μm range for the graphene application.

This work is devoted to the investigation of the discharge characteristics of high-frequency alternating current (ac) plasma torch working with air medium using electrical and spectroscopic techniques. A simple structure and compact ac plasma torch associated with a resonance power supply allows the generation of low power discharges (lower than 1 kW) with high voltage and low current. The discharge shows a negative resistance characteristic, and its curve shifts up with gas flow increased. The effects of power on the emission intensity of NO (A 2 � + → X 2 � ), OH (A 2 � → X 2 � , 0–0), N2 (C 3 � u → B 3 � g), Hα and O (3p 5 P→3S 5 S 0 ) and their spatial distributions in plasma jet axial direction were investigated. It has been found that the emission intensities of NO, OH, N2 ,H α and O rise with an increase in power dissipation. With increasing axial distances of plasma jet from nozzle exit, the emission intensity of OH increases and then decreases, while the emission intensities of other species decrease sharply. The vibrational temperature is much higher than the gas temperature, which demonstrates the ac-driven arc discharge deviation from thermal equilibrium plasma. (Some figures may appear in colour only in the online journal)