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We designed, assembled, and tested a reliable laser system for 87Rb cold atom fountain clocks. The laser system is divided into four modules according to function, which are convenient for installing, adjusting, maintaining, and replacing of the modules. In each functional module, all optical components are fixed on a baseplate with glue and screws, ensuring the system’s structural stability. Mechanical stability was verified in a 6.11g RMS randomvibration test, where the change in output power before and after vibration was less than 5%. Thermal stability was realized by optimizing of the structure and appropriate selection of component materials of the modules through thermal simulation. In the laser splitting and output module, the change in laser power was less than 20% for each fiber in thermal cycles from 5 °C to 43 °C. Finally, the functionality of the laser system was verified for a rubidium fountain clock.

A continuous wave (CW) Watt-level wavelength-variable low-noise all-solid-state yellow-green laser was developed by using the Brewster polarizer frequency selection and birefringent crystal filtering methods. The maximum CW output power of the yellow-green laser beams radiating at wavelengths of 556.32 nm, 558.36 nm and 561.63 nm was measured to be 2.922 W, 2.713 W and 2.514 W, respectively. When the CW output power was 2.5 W within 4 h, the power instability of the three yellow-green laser beams from the shortest wavelength to longest wavelength was ±0.55%, ±0.46%, and ±0.69%, respectively. Their corresponding laser noise was 0.65%, 0.48%, and 0.72%. To the best of our knowledge, the Watt-level wavelength-variable all-solid-state yellow-green laser with low noise proposed in this study is the first of its kind.

Significant decoherence of the plasmon-emitter (i.e., plexcitonic) strong coupling systems hinders the progress towards their applications in quantum technology due to the unavoidable lossy nature of the plasmons. Inspired by the concept of spectral-hole-burning (SHB) for frequency-selective bleaching of the emitter ensemble, we propose ‘cavity SHB’ by introducing cavity modes with moderate quality factors to the plexcitonic system to boost its coherence. We show that the detuning of the introduced cavity mode with respect to the original plexcitonic system, which defines the location of the cavity SHB, is the most critical parameter. Simultaneously introducing two cavity modes of opposite detunings, the excited-state population of the emitter can be enhanced by 4.5 orders of magnitude within 300 fs, and the attenuation of the emitter’s population can be slowed down by about 56 times. This theoretical proposal provides a new approach of cavity engineering to enhance the plasmon-emitter strong coupling systems’ coherence, which is important for realistic hybrid-cavity design for applications in quantum technology.

A new algorithm for reconstructing the three-dimensional flow field of the oceanic mesoscale eddies is proposed in this paper, based on variational method. Firstly, with the numerical differentiation Tikhonov regularizer, we reconstruct the continuous horizontal flow field on discrete grid points at each layer in the oceanic region, in terms of the horizontal flow field observations. Secondly, benefitting from the variational optimization analysis and its improvemen, we reconstruct a three-dimensional flow field under the constraint of the horizontal flow and the vertical flow. The results of simulation experiments validate that the relative error of the new algorithm is lower than that of the finite difference method in the case of high grid resolution, which still holds in the case of unknown observational errors or in the absence of vertical velocity boundary conditions. Finally, using the reanalysis horizontal data sourcing from SODA and the proposed algorithm, we reconstruct three-dimensional flow field structure for the real oceanic mesoscale eddy.

The influence of marine environment on the reliability of a certain type of aviation connectors is studied. Firstly, the step-stress accelerated degradation test which simulates marine environment in South China Sea is designed. And the performance parameter data of four material types of aviation connectors: stainless steel, composite cadmium plating, titanium alloy and aluminum alloy cadmium plating are collected. And then, in order to study the degradation of performance parameters, the mixed effect model is adopted. At last, the reliability lifetime of four material types of aviation connectors are evaluated by means of reliability modeling and analysis. This research provides an effective path for reliability evaluation of aviation connectors, meanwhile it also gives a reference for aviation connectors’ selection.

We study the ferromagnetic transition of a two-component homogeneous dipolar Fermi gas with 1D spin–orbit coupling (SOC) at finite temperature. The ferromagnetic transition temperature is obtained as functions of dipolar constant λ d, spin–orbit coupling constant λ SOC and contact interaction constant λ s. It increases monotonically with these three parameters. In the ferromagnetic phase, the Fermi surfaces of different components can be deformed differently. The phase diagrams at finite temperature are obtained.

With the increasing scale and quantity of civil aviation information system, the data carried in the information system is becoming more and more important and sensitive. In the face of a large number of information systems, sorting out and monitoring whether passenger information in the information system has been accessed in violation of regulations is an urgent problem in the civil aviation industry. In this paper, the civil aviation business system is deeply studied, and a method of identifying abnormal access to sensitive data based on network traffic is proposed. Through the collection and analysis of network traffic, and then identify the sensitive information in the network traffic, and use k-means clustering method to classify the access behavior of sensitive information. Finally, combined with expert experience, the malicious access behavior for sensitive data is accurately identified.

In this study, a cetylpyridinium bromide (CPB)/montmorillonite-graphene oxide (GM) composite (GM-CPB) was prepared by loading CPB in a carrier of GM. The chemical structure, elemental composition, morphology, thermogravimetric analysis, antibacterial activity, sustained release property and cytotoxicity were analyzed. The loading rate of CPB in a GM carrier was higher than that of the graphene oxide (GO) carrier under the same loading condition. The antibacterial activity and sustained release performance of GM-CPB were also better than that of GO-CPB; furthermore, GM-CPB showed lower cytotoxicity than CPB.

Full-Heusler compounds have three crystal structures with a different order degree; the highly ordered L21, partially disordered B2, and completely disordered A2 structures. To reveal the effects of the order degree on thermoelectric (TE) properties of the full-Heusler compounds, Mn2VAl samples with varied L21 and B2 order degrees are prepared by changing preparation conditions, and their Seebeck coefficients and electrical conductivities are measured in a wide temperature range. As the B2 order degree becomes higher, the Seebeck coefficient increases, leading to the increase of the power factor (PF). The maximum PF is 2.84 × 10−4 Wm−1 K−2 at 767 K for the Mn2VAl sample with the highest B2 order degree. This study demonstrates that the TE properties of Mn2VAl can be enhanced by increasing the fraction of the B2 phase. A relation between the Seebeck coefficient and crystal structures is also discussed based on the calculation of the electronic density of states of Mn2VAl with the L21 and B2 structures.

We study a homogeneous two-component dipolar Fermi gas with 1D spin-orbit coupling (SOC) at zero temperature and find that the system undergoes a transition from the paramagnetic phase to the ferromagnetic phase under suitable dipolar interaction constant λ d, SOC constant λ SOC and contact interaction constant λ s. This phase transition can be of either 1st order or 2nd order, depending on the parameters. Near the 2nd-order phase transition, the system is partially magnetized in the ferromagnetic phase. With SOC, the ferromagnetic phase can even exist in the absence of the contact interaction. The increase in dipolar interaction, SOC strength, and contact interaction are all helpful to stabilize the ferromagnetic state. The critical dipolar interaction strength at the phase transition can be reduced by the increase in SOC strength or contact interaction. Phase diagrams of these systems are obtained.

At present, aero-engines face a major need to widen the ignition envelope. In order to provide a technical support to expand the high altitude ignition envelope of aero-engines, in this article we propose a novel ignition technology, i.e., “pre-combustion plasma jet ignition technology”. In this paper, we also design a pre-combustion plasma jet igniter. Its discharge characteristics, jet characteristics, and ignition effects are studied. The results show that increasing the equivalent ratio of jet gas can enhance the discharge stability and increase the duty cycle. At the same time, it can reduce working power and energy consumption. The increase of equivalent ratio in jet gas can enhance the length and ignition area of plasma jet. In the process of ignition, the pre-combustion plasma jet igniter has obvious advantages, suchn as shortening the ignition delay time and enlarging the ignition boundary. When the airflow velocity is 39.11 m/s and the inlet air temperature is 80 °C, compared with the spark igniter and the air plasma jet igniter, the pre-combustion plasma jet igniter has an ignition boundary that is expanded by 319.8% and 55.7% respectively.

In this paper, the STM32 microprocessor is used as the central control core, and a 500W photovoltaic inverter is designed. The inverter adopts a two-stage conversion structure. The high-speed timer of the STM32 microprocessor generates high-resolution PWM and SPWM pulses and drives the first-stage DC/DC convertor after driving the chip through UCC27324 and IR2111 respectively. The rectification and the second-stage DC/AC inverter convert the DC signal into a utility frequency. In order to reduce the higher harmonics derived from the DC/AC inverter, the circuit also adopts the principle of LC filter design. Finally, in the Multisim simulation, the operation is stable. The error of the output AC voltage is controlled within 3%. It is said that the inverter has the advantages of high reliability, low harmonic content, and high efficiency.

As the melted iron and zirconia toughened alumina particles are non-invasive, it is always a critical problem to realize the infiltration between melted iron and ceramic particles. The solidification process of high chromium cast iron matrix composites reinforced by zirconia toughened alumina ceramic particles by infiltration casting is simulated using finite element analysis method in this paper. Two physical modules, heat transfer in solid and solid mechanics are used to describe the solidification phenomenon. The variation and distribution of stress field and temperature field during solidification are analyzed. By comparing the stress of different diameter/wall thickness ratio, the optimal diameter/wall thickness ratio for performance is found to be 1.5 to realize the infiltration process. Compared with the experimental results, it shows that the simulation results are in accordance with the experiments results, so the established model and simulation methods are correct, and can provide the foundation for the further research.

Multifunctional theranostic agents are widely applied in cancer diagnosis and treatment. These agents can significantly improve therapeutic outcomes and reduce adverse effects in current cancer therapy. Here, we have designed and synthesized iron-doped copper sulfide nanoparticles with polyvinylpyrollidone (FCS@PVP NPs) for magnetic resonance imaging (MRI) guided photothermal therapy. The biocompatible FCS@PVP NPs with strong near-infrared absorption could be used as the photothermal agent and the magnetic characteristic of Fe3+ ions could be applied to T 1-weighted magnetic resonance imaging (MRI). The T 1-weighted MRI, high photothermal performance, and the biodistribution of FCS@PVP NPs were investigated in mice after intravenous administration. The data showed that there was a high accumulation of FCS@PVP NPs in the tumor sites because of the enhanced permeability and retention (EPR) effect. This result also indicated that the tumors in tumor-bearing mice were effectively suppressed after FCS@PVP NPs treatment under 808 nm laser irradiation. More importantly, FCS@PVP NPs show low cytotoxicity and few side effects because of the quick and safe elimination through the hepatobiliary/fecal route. This work provided a foundation for the clinical application of FCS@PVP NPs as a promising multifunctional theranostic agent for the MRI guided photothermal therapy of cancer.

Micro-TE (thermoelectric) devices have received increasing attention because of their promising applications as energy resources for micro-systems. However, poor performance and complicated fabrication process has limited their application. This work demonstrates that micro-TEGs (thermoelectric generators) with a large output power of 218 μW and output voltage of 34.7 mV under a larger temperature difference of 98 K can be fabricated using electro-deposition based on the multi-channel glass template, which is much higher than that of other reported work. The micro-TEGs consisted of four pairs of thermocouples. Each thermocouple was composited by about 200 p-type legs of Sb2Te3 and 200 n-type legs of Bi2Te3 60 μm in diameter and 200 μm in height, and were well filled in the glass template by impulse voltage deposition. The length of the TE legs can be adjusted by increasing the length of the channel, which led the large temperature difference and high output power and output voltage. Additionally, the glass template which shows low thermal conductivity and is electrically insulating, can be retained after being filled with TE materials, which simplifies the device fabrication process and also helps to enhance the rigidity of the TE modules. Moreover, this work also reveals that the output voltage can be further improved by increasing the numbers of thermocouples via decreasing the numbers of legs in each thermocouple.

A new thermodynamic and kinetic calculation method to be applied to nanocrystalline materials is proposed. The diffusion behavior of Ti atoms in pure nanocrystalline Fe is described by our vacancy model, first-principles calculations, and experimentally. First principles calculation results showed that the diffusion barrier in a one-vacancy structure was 0.659 eV, and in a two-vacancy structure it was 0.353 eV. The diffusion temperature of Ti atoms in pure Fe nanocrystalline was 400 °C, which was significantly lower than the corresponding value in bulk. Pure Fe surface mechanical attrition treatment (SMAT) was performed to increase the surface vacancy concentration and depress the Debye temperature. Experimental results were in good agreement with the theoretical calculations.