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In order to realize that the fuze micro system has both high security and miniaturization characteristics, the spark gap research of Micro-Electro-Mechanical System safety system is carried out. So that to solve the safe and reliable function of the spark gap switch under the low power supply voltage (35 V) of the fuze micro system, the gas gap size and electrode radius are shown to significantly affect the gas breakdown voltage using streamer theory. Based on these results, a spark gap switch with triggering electrodes is designed. The triggering electrode gap is 2 μm and the main electrode gap is 10 μm. A spark gap switch test circuit is designed based on the RLC circuit. Through finite element simulation, it is verified that the gas breakdown voltage increases nonlinearly with increasing gap size. Pre-breakdown spark gap switches were fabricated based on the surface silicon process and tested. The test results show that the conduction voltage values of the triggering electrode and the main electrode are basically consistent with the simulation and calculation results. The breakdown voltage of the main electrode can be greatly reduced by applying a certain voltage to the triggering electrode, realize the reliable function in the micro fuze system.

3 numerical models of laser deposited TA15/Ti2AlNb gradient composite structure were established to simulate the temperature variation of gradient composite structures with different gradient layers in different regions. Then TA15/Ti2AlNb gradient composite structures with different gradient layers were prepared by laser deposition technology. The microstructure, room-temperature tensile properties and microhardness of the deposited samples were observed by optical microscope, tensile testing machine, scanning electron microscope and microhardness tester. The results showed that as the number of gradient layers increased, the temperature in the deposition process of the transition zone increased, while the microstructure difference in the transition zone decreased gradually. As the number of transition layers increased, the tensile strength decreased, but the elongation after fracture increased. All the fracture locations were in the transition zone, and with the increasing of gradient layers, the fracture location gradually shifted to the Ti2AlNb side. The microhardness of the transition zone increased with the increasing of gradient layers. This study will provide reference for the optimization design of TA15/Ti2AlNb gradient composite structure.

The principle and structure of the 75kW oil-free turbo blower is briefly introduced and the performance of gas foil bearings (GFBs) is tested. According to the test results, the lift-off speed of the gas foil journal bearings (GFJBs) using in 75kW oil-free turbo blower is about 4000rpm, and the gas foil thrust bearings (GFTBs) can provide at least 140N and 200N load capacity at 7200rpm and 9000rpm, respectively. The rotordynamics behavior of oil-free turbo blower is studied. Two proximity probes and speed sensor are installed to monitor the horizontal vibration displacement, vertical vibration displacement and shaft speed, respectively. And the vibration spectrum and the rotor axis orbit are analyzed. It was found that the maximum vibration amplitude of the rotor with dynamic balancing precision of G-1 was only 3.5 μm, and no other low frequency other than low frequency caused by signal interference. The fundamental frequency vibration amplitude of the rotor with dynamic balancing precision of G-2.5 is larger when running stably, but there is no low frequency and high frequency vibration with higher amplitude. Shaft couldn’t lift-off with dynamic balancing precision of G-6.3 In general, oil-free turbo blower with two kinds of dynamic balancing precision rotors can operate well.

It has always been a research hotspot in the field of the transmission engineering to research on the stability of high-voltage transmission lines under strong wind and establish effective measures to prevent the wind disaster. Wind disasters such as the structure deformation, tower collapse and line disconnection affect the safety of transmission lines seriously, which trouble the technicians a lot. The long-span, high-flexibility and strong coupling characteristics of the tower-line system itself determine that it is extremely sensitive to external random loads. From the theoretical perspective, effective conclusion of the analysis on the wind-induced response of the tower-line system can be obtained only by following the inherent coupling characteristics of the tower-line system, the spatial distribution correlation of the strong wind in the large field and the probability characteristics of wind-induced response closely, which is also the focus of this paper. A specific 220kV transmission line was chosen as the research object in this paper. First of all, a refined finite element model of the high-voltage tower-line system was established which takes the tower-line coupling factors into account. Then, considering the non-Gaussian and spatial distribution correlation characteristics, a numerical simulation method of the strong wind in large field was provided. On this basis, the comparative analysis of the wind-induced response of the tower-line system was completed and the probability density function of the key mechanical parameters of the tower-line system was established and analyzed finally. The models and methods proposed in this paper are verified to be correct and more close to the actual working conditions, which can provide reference for the study of the transmission line operation, maintenance and wind disaster prevention.

In this work, PEDOT: PSS 1000 was used as hole transporting layer to fabricate high luminescent perovskite light-emitting diodes. Combined with potassium doping strategy, the according perovskite light-emitting diode reaches a high brightness of 40 000 cd/m2.

2D perovskites, typically with a standard formula of L2An-1MnX3n+1, have recently attracted significant attention due to their promising optoelectronic properties. Normally, they contain a mono cation (e.g., butylammonium (BA+) or phenylethylammonium (PEA+) for “L” and methylammonium (MA+) or formamidinium (FA+) for “A”). In this work, multiple cation-substitution strategy was used to improve the luminescence and emission efficiency of perovskite thin films. As a result, brightly blue emission with a high photoluminescence quantum yield of 26% was achieved. Finally, the according perovskite light-emitting diodes reached a brightness of 110 cd/m2, and a maximum external quantum efficiency of 0.79%.

We report on the micron-sized light-absorbing particle trapping in two configurations (horizontal and vertical), in order to elucidate the laser trapping mechanism based on the photophoretic force. Two types of carbon particles (irregular graphite particles and carbon microspheres) were tested in both Gaussian and hollow beam traps. By comparing the trapping efficiency and stability under various circumstances, we confirmed that there are two types of photophoretic forces: and forces on the laser irradiating particle. Furthermore, the forces and moments exerting the particles in various traps were analyzed, which explained the experimental phenomena very well. It was found that the force due to the thermal accommodation difference among the irregular particles helps the irregular particles to be balanced more easily and of higher trapping efficiency and stability. This work provides important references for people to choose a suitable trapping scheme according to the particles, which would be of significance in the applications of single-particle analysis.

A new linear accelerator system, called the SSC-Linac injector, is being designed at HIRFL (the heavy ion research facility of Lanzhou). As part of the SSC-Linac, the medium energy beam transport (MEBT) consists of seven magnetic quadrupoles, a re-buncher and a diagnose box. The total length of this segment is about 1.75 m. The beam dynamics simulation in MEBT has been studied using the TRACK 3D particle-in-cell code, and the simulation result shows that the beam accelerated from the radio frequency quadrupole (RFQ) matches well with the acceptance of the following drift tube linac (DTL) in both the transverse and longitudinal phase spaces, and that most of the particles can be captured by the final sector focusing cyclotron for further acceleration. The longitudinal emittance of the RFQ and the longitudinal acceptance of the DTL was calculated in detail, and a multi-particle beam dynamics simulation from the ion source to the end of the DTL was done to verify the original design.

A new procedure for the design and simulation of a Radio Frequency Quadrupole (RFQ) accelerator has been developed at the Argonne National Laboratory. This procedure is integrated with the beam dynamics design code DESRFQ and the simulation code TRACK, which are based on three-dimensional field calculations and the particle-in-cell mode beam dynamics simulations. This procedure has been applied to the development of a 162.5 MHz CW RFQ which is capable of delivering a 10 mA proton beam for the Accelerator Driven System (ADS) of the CAS. The simulation results show that this RFQ structure is characterized by the stable values of the beam acceleration efficiency for both the zero current beam and space charge dominated beam. For an average beam current of 10 mA, there is no transverse rms emittance growth, the longitudinal rms emittance at the exit of RFQ is low enough and there is no halo formation. The beam accelerated in the RFQ could be accepted easily and smoothly by the following super-conducting linear accelerator.

The ABC code is an optimization program for the development of matching channels and dynamical matchers in radio frequency quadrupole (RFQ) structures, and a new approach to this code to define the geometry of the radial matching section of the RFQ has been developed. This approach is based on the application of the numerical optimization step by step. This optimization is intended to search for the initial matching condition of a beam, the optimization of parameters of a cell of the channel on given characteristic parameters and traces of a beam in linear channels in both forward and backward directions. To further verify the results of the optimization, multi-particle beam dynamics simulations have been carried out using the BEAMPATH and TRACK codes. The result of the beam dynamics simulation shows that the optimization result of the ABC code is reasonable and this approach provides an opportunity to redesign the structure of the radial matching section of the RFQ.

The electric vehicle market has witnessed a big growth spurt as a result of the promotion of the transportation electrification in the global. Among electric vehicles, electric passenger cars are the most promising fleet to achieve the global climate target in the next decades, which will lead to a vast potential public charging market. Therefore, evaluating the economy of operating the charging infrastructure from the operator's perspective is especially required. The paper aims at providing an economic evaluation of charging infrastructure in public places in China. In the proposed method, the initial investment cost, the subsidy, the operating revenue and the operating cost are all modeled in detail. Using the proposed model, two scenarios representing the electric vehicle charging in the work place and in the fast charging station are assumed, and the cost and revenue of charging operators are calculated and compared. It is shown that under our assumption the payback period of the charging infrastructure in the work place is much shorter than that of fast charging station. Because the calculated payback period of fast charging station is more than ten years, current fast charging stations are unlikely to profit, and the promotion of the fast charging stations requires further policy support and smart grid technology development.

We report micron-sized particle trapping and manipulation using a hollow beam of tunable size, which was generated by cross-phase modulation via the thermal nonlinear optical effect in an ethanol medium. The results demonstrated that the particle can be trapped stably in air for hours and manipulated in millimeter range with micrometer-level accuracy by modulating the size of the hollow beam. The merits of flexibility in tuning the beam size and simplicity in operation give this method great potential for the in situ study of individual particles in air.

This work presents the development of a wettability switching membrane device using the surface roughness effect. We designed and fabricated a roughness switchable membrane device, consisting of a thin poly(dimethylsiloxane) (PDMS) membrane bonded on the top of a rough PDMS substrate. A thin (less than 2 µm) PDMS membrane fabrication technique was developed. The membrane device was tested and it was found that the surface wettability can be switched from medium hydrophobic to superhydrophobic states by deflecting the membrane with a pneumatic method. The reported mechanism is the first demonstration of a wettability switching mechanism using surface roughness modification. Theoretical analysis was used to explain experimental results.

In this paper, the influence of the active layer nanomorphology on device performance for ternary PbS(x)Se(1-x) quantum dot-based solution-processed infrared photodetector is presented. Firstly, ternary PbS(x)Se(1-x) quantum dots (QDs) in various chemical composition were synthesized and the bandgap of the ternary PbS(x)Se(1-x) QDs can be controlled by the component ratio of S/(S + Se), and then field-effect transistor (FET) based photodetectors Au/PbS0.4Se0.6:P3HT/PMMA/Al, in which ternary PbS0.4Se0.6 QDs doped with poly(3-hexylthiophene) (P3HT) act as the active layer and poly(methyl methacrylate) (PMMA) as the dielectric layer, were presented. By changing the weight ratio of P3HT to PbS0.4Se0.6 QDs (K = M(P3HT):M(QDs)) in dichlorobenzene solution, we found that the device with K = 2:1 shows optimal electrical property in dark; however, the device with K = 1:2 demonstrated optimal performance under illumination, showing a maximum responsivity and specific detectivity of 55.98 mA W(-1) and 1.02 × 10(10) Jones, respectively, at low V(DS) = -10 V and V(G) = 3 V under 980 nm laser with an illumination intensity of 0.1 mW cm(-2). By measuring the atomic force microscopy phase images of PbS0.4Se0.6:P3HT films in different weight ratio K, our experimental data show that the active layer nanomorphology has a great influence on the device performance. Also, it provides an easy way to fabricate high performance solution-processed infrared photodetector.

A polarization-independent phase-gradient metasurface (PGM) is proposed, and theoretically as well as experimentally investigated, for realizing spoof surface plasmon polariton (SPP) coupling. The designed PGM is a periodic array comprising a dielectric substrate sandwiched between a metallic split cross structure and a continuous metallic film. The numerical results for the designed PGM indicate that normally incident electromagnetic waves can be efficiently coupled into spoof SPPs, since the additional wave vector generated by the designed PGM is greater than that of the incident waves. Both simulations and experiments demonstrate that the designed PGM, as a spoof SPP coupler, is insensitive to polarization, and highly efficient under normally incident X-band radiation.

A superconducting half-wave resonator (HWR) of frequency=162.5 MHz and {\beta}=0.09 has been developed at Institute of Modern Physics. Mechanical stability of the low beta HWR cavity is a big challenge in cavity design and optimization. The mechanical deformations of a radio frequency superconducting cavity could be a source of instability, both in continues wave(CW) operation or in pulsed mode. Generally, the lower beta cavities have stronger Lorentz force detuning than that of the higher beta cavities. In this paper, a basic design consideration in the stiffening structure for the detuning effect caused by helium pressure and Lorentz force has been presented. The mechanical modal analysis has been investigated with finite element method(FEM). Based on these considerations, a new stiffening structure has been promoted for the HWR cavity. The computation results concerning the frequency shift show that the low beta HWR cavity with new stiffening structure has low frequency sensitivity coefficient, Lorentz force detuning coefficient KL and stable mechanical property., Comment: this work is supported by Strategic Priority Research Program of CAS (Grant No. Y1020700ADS)and National Natural Science Foundation of China (Grant No. 91026001)

A new node-pairs contact algorithm is proposed to deal with a composite material or bi-material interface crack face contact and friction problem (e.g., resistant coating and thermal barrier coatings) subjected to complicated load conditions. To decrease the calculation scale and calculation errors, the local Lagrange multipliers are solved only on a pair of contact nodes using the Jacobi iteration method, and the constraint modification of the tangential multipliers are required. After the calculation of the present node-pairs Lagrange multiplier, it is turned to next contact node-pairs until all node-pairs have finished. Compared with an ordinary contact algorithm, the new local node-pairs contact algorithm is allowed a more precise element on the contact face without the stiffness matrix singularity. The stress intensity factors (SIFs) and the contact region of an infinite plate central crack are calculated and show good agreement with those in the literature. The contact zone near the crack tip as well as its influence on singularity of stress fields are studied. Furthermore, the frictional contacts are also considered and found to have a significant influence on the SIFs. The normalized mode-II stress intensity factors II for the friction coefficient decrease by 16% when f changes from 1 to 0.

We present a robust method of single-photon modulation by directly modulating the single photons and observe its frequency spectrum. Compared with conventional photon counting technique, the single-photon modulation spectrum shows that the method could not only realize high-frequency modulation but also obtain higher signal-to-noise ratio. Moreover, the theoretical calculations show good agreement with the experimental results.

The taper-shaped superconducting quarter wave resonators with frequency of 80.5 MHz, β of 0.041 and 0.085 have been pre-researched. The radio frequency (RF) design of the cavities has been completed, and the structural design is also an important aspect which will be discussed in the following. The frequency shift caused by the etching effects of the surface treatment, the helium bath pressure and the Lorentz force, and the mechanical modes caused by the microphonic excitation have been analyzed. The results show that the frequency variation from the Lorentz force is not serious and stiffening rings are explored aimed at decreasing the deformation brought by the helium pressure and microphonic excitation.

We present a method of directly measuring DBR fiber laser linewidth with the sidebands' interference based on the phase modulations. The interference visibility depending on the modulation frequency difference between the two phase modulators is obtained, and the results are fitted with a Voigt function to extract the Lorentzian and Gaussian linewidths. The experimental result of a DBR fiber laser linewidth is 532 ± 14 Hz. The effects of a 25 km fiber on the Lorentzian and Gaussian broadening have been demonstrated experimentally.

The laser damage resistances of four crystals (CaF2, MgF2, Al2O3, and SiO2) and fused silica (JGS1) irradiated at 355 nm (8 ns, 300-on-1) are reported. The laser-induced damage threshold is measured using a tripled Nd:YAG laser system. The results obtained from the pure crystals are in accordance with their specific optical, mechanical, and thermal properties. An empirical law based on the Franz—Keldysh effect can interpret the experimental results.

The complexities of multi-wing chaotic systems based on the modified Chen system and a multi-segment quadratic function are investigated by employing the statistical complexity measure (SCM) and the spectral entropy (SE) algorithm. How to choose the parameters of the SCM and SE algorithms is discussed. The results show that the complexity of the multi-wing chaotic system does not increase as the number of wings increases, and it is consistent with the results of the Grassberger—Procaccia (GP) algorithm and the largest Lyapunov exponent (LLE) of the multi-wing chaotic system.

A modified Polyacrylamide gel route is applied to synthesize SnO2 nanoparticles. High-quality SnO2 nanoparticles with a uniform size are prepared using different chelating agents. The average particle size of the samples is found to depend on the choice of the chelating agent. The photoluminescence spectrum detected at λex = 230 nm shows a new peak located at 740 nm due to the surface defect level distributed at the nanoparticle boundaries.

High temperature annealing is often used for the stress control of optical materials. However, weight and viscosity at high temperature may destroy the surface morphology, especially for the large-scale, thin and heavy optics used for large laser facilities. It is necessary to understand the thermal behaviour and design proper support systems for large-scale optics at high temperature. In this work, three support systems for fused silica optics are designed and simulated with the finite element method. After the analysis of the thermal behaviours of different support systems, some advantages and disadvantages can be revealed. The results show that the support with the optical surface vertical is optimal because both pollution and deformation of optics could be well controlled during annealing at high temperature. Annealing process of the optics irradiated by CO2 laser is also simulated. It can be concluded that high temperature annealing can effectively reduce the residual stress. However, the effects of annealing on surface morphology of the optics are complex. Annealing creep is closely related to the residual stress and strain distribution. In the region with large residual stress, the creep is too large and probably increases the deformation gradient which may affect the laser beam propagation.

The local structure and dielectric properties of crystalline and amorphous La2Hf2O7 (LHO) thin film were studied by X-ray absorption spectroscopy and infrared spectroscopy. The basic infrared phonon modes with most contributions to the static dielectric constant of crystal LHO are preserved, which causes the considerable value of the static dielectric constant in the amorphous thin film. The preservation of the main infrared phonon modes in the amorphous thin film is because it has similar the nearest local structures around Hf and La atoms as the crystal LHO. This inheritance of the local structural and vibrational features of the crystal phase is the origin of the dielectric constant of the LHO thin film.

Epoxy resins were materials with excellent mechanical, electrical properties and good chemical stability. Thus, they had been used in various fields, especially in electrical and electronic application. However, because they were brittle material, the fields of application were limited. Adding nano-Aluminum Nitride (AlN) into Epoxy resins could improve the toughness of the composites, the thermal behaviors of composites could also be improved, but the influence on dielectric properties was not very clear. In this research, epoxy resin based composites were fabricated. The relationships between the dielectric properties and the nano-AlN particle content were investigated. The results showed that, both relative permittivity (r) and dielectric loss tangent (tanδ) decreased to be less than that of monolithic epoxy when nano-AlN particle content was no more than certain amount, the DC volume resistivity (ρv) and low frequency resistivity decreased with increasing nano-AlN content (in certain range of content). AC breakdown strength (EB) did not have an obvious tendency with nano-AlN content.

Both AlN/ nano h-BN composites and AlN/ micro h-BN composites were fabricated. The high temperature oxidation behaviors were investigated at 1000°C and 1300°C using a cycle-oxidation method. The results showed that there were little changes of both nano composites and monolithic AlN ceramic at temperature of 1000°C. And at 1300°C, the oxidation dynamics curve of composites could be divided into two courses: a slowly weight increase and a rapid weight decrease, but the oxidation behavior of nano composites was better than micro composites. It was due to that the uniform distribution of oxidation production (Al18B4O33) surround the AlN grains in nano composites and the oxidation proceeding was retarded. The XRD analysis and SEM observations showed that there was no BN remained in the composites surface after 1300°C oxidation and the micropores remain due to the vaporizing of B2O3 oxidized by BN.

Single-crystalline Ni-doped ZnO nanorods have been synthesized through a chemical method. The average length and diameter of these nanorods are in the ranges of 400?700?nm and 25?40?nm, respectively. Structural analyses reveal that the Ni-doped ZnO nanorods are of pure wurtzite hexagonal phase and grow along the preferred c-axis direction. X-ray photoelectron spectroscopy (XPS) gives evidence that the Ni dopant is in the +2 valence oxidation state and is uniformly distributed in the nanorods. Full multiple-scattering ab initio calculations of Ni K-edge x-ray absorption near edge structure (XANES) analysis reveal that Ni impurity atoms are substitutionally incorporated into ZnO host without formation of secondary phases (Ni metal and Ni2O3). The comparison of experimental and simulated XANES spectra on Ni K edge shows the presence of the oxygen vacancy (native defect) in the prepared nanorods. Photoluminescence spectrum shows two emission peaks, which are ascribed to near band edge (NBE) transitions and broadened intensive green emission associated with oxygen-vacancy defects. Furthermore, the magnetic measurements reveal that the nanorods exhibit intrinsic room-temperature ferromagnetism. Ferromagnetic ordering is interpreted by the overlapping of polarons mediated through oxygen vacancy based on the bound magnetic polaron (BMP) model.

Cu and Co ions co-doped Zn0.95?xCuxCo0.05O (0 ? x ? 0.08) diluted magnetic semiconductors (DMSs) prepared by the sol?gel method were investigated by x-ray absorption fine structure (XAFS). Although the Co K-edge XAFS data indicate that the doped Co ions are located substitutionally at the Zn sites for all the Zn0.95?xCuxCo0.05O DMSs, the CuK-edge XAFS analysis combined with XRD results reveals that the doped Cu ions are separated to form a CuO phase for samples calcined at 1073?K. After being sintered at a higher temperature of 1473?K, the Cu ions with low Cu concentration (x ? 0.02) are substantially incorporated into the ZnO host lattice, while a small proportion of CuO clusters still coexist in the samples with a higher Cu concentration (x ? 0.05). The solubility of the doped Cu ions in Zn0.95Co0.05O DMS is estimated as about 0.04. The results provide experimental guidance in the synthesis of the co-doped ZnO based DMSs.