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Due to the unique self-acceleration, self-healing, and non-diffraction properties, Airy beams have been explored extensively and found applications in various fields. It has been proven as an essential aspect to tune the trajectory of Airy beams for extensive applications. In this paper, we propose a method based on liquid crystal (LC) alignment with metasurfaces, which enables dynamic tuning of the trajectory of Airy beams. Benefiting from both the tunable property of LCs and the compact alignment of metasurfaces, we achieve a sizeable linear potential in a short distance, which leads to the effective tuning of the trajectory of Airy beams dynamically. The introduction of metasurfaces into the alignment of LCs provides a promising method to manipulate the planar optical field.

Aiming at the problem of corrosion detection of buried gathering and transportation pipeline under trenchless conditions，a selfleakage magnetic field model for corrosion defects of buried gathering and transportation pipeline was established based on the magnetic dipole model and considering the magnetic charge distribution of corrosion defects.The waveform characteristics of magnetic induction intensity of corrosion defects and the effects of different height off the ground and size of corrosion defects on the magnetic induction intensity were studied by numerical simulation.Results showed that at the corrosion defect，Bx and Bz presented extreme value characteristics and the direction was opposite，By had the feature of passing zero and the peak value changed the direction；the height off the ground was inversely proportional to the extreme values of Bx and Bz and the peak values of By；the size of corrosion defect was proportional to the extreme values of Bx and Bz and the peak value of By.According to the oilfield field testing data，14 excavation points were selected to verify the distribution characteristics of magnetic induction intensity of corrosion defects，and 3 excavation points were selected to verify the relationship between the height off ground and the size of corrosion defects and magnetic induction intensity.

In order to realize the detection of buried pipes without excavation and provide a theoretical basis for the weak magnetic inspection, the spatial magnetic signal distribution of corroded pipelines under the influences of internal pressure and geomagnetic field was studied using ANSYS finite element software. The effects of varing uplifting heights on the magnetic signal of pipeline defects and the distribution of magnetic signal under different defect depths were analyzed. Furthermore, the pipeline was detected on site by a self - made pipeline weak - magnetic detection instrument, and the detected magnetic signal was compared with the simulated result to verify the consistency. Based on the magnetic signal characteristics regarding corrosion position judgment obtained by simulation analysis, the detected magnetic signal data was analyzed, and the defect location was verified by excavation. Results showed that the recognition of corrosion defects and non-contact detection of buried magnetic pipelines could be realized by using this waveform feature.

The long - term stress damage caused by working load and additional load seriously affects the safe operation of the pipeline. Aimed at the stress detection of buried gas pipelines, the research was carried out on the pipeline weak magnetic stress external detection technology. By establishing the equivalent magnetic dipole model of the pipeline stress concentration zone, the numerical simulation of the normal component By and the tangential component Bx was carried out using Matlab software, and the distribution characteristics of the magnetic field components in stress concentration zone were obtained. A weak magnetic stress external detection on the Nanqi line 2 km gas pipeline under Changqing Oilfield combined with the magnetic field distribution characteristics of the stress concentration area obtained from the above - mentioned simulation analysis, 6 medium - risk stress damages and 14 low - risk stress damages were detected. The contact metal magnetic memory (MMM) detector was used to conduct excavation detection on two selected feature points. The MMM detection results of the two excavated pits were consistent with the pipeline weak magnetic stress external detection results. Results showed that the pipeline weak magnetic stress external detection technology was a new technology that could effectively detect pipeline stress damages, predict pipeline hazards and thus played an important role in assisting the safety management of pipelines.

Objective: This study focuses on improving the stability and water solubility of astaxanthin. Methods: Phytosterol α-linolenic acid ester was synthesized by chemical method with phytosterol and α-linolenic acid as raw materials. Liposomes co-encapsulating astaxanthin and phytosterol α-linolenic acid ester were prepared by employing a thin-film ultrasound technique with the utilization of soybean phospholipid. Results: Based on the structure analysis by infrared spectroscopy and nuclear magnetic resonance, it has been demonstrated that the product was phytosterol α-linolenic acid ester. The purity of phytosterol α-linolenic acid ester was （90.72±2.09）% by gas chromatography. The encapsulation efficiency of liposomes co-encapsulating astaxanthin and phytosterol α-linolenic acid ester were （95.00±0.66）%, the average particle size was （158.70±9.70） nm, the polydispersity index （PDI） was 0.35±0.02, and the average zeta potential was （-33.87±2.48） mV. Transmission electron microscopy revealed that the complex liposomes were spherical with regular shape and uniform particle size distribution. Conclusion: Phytosterol α-linolenic acid ester could be applied in the preparation of astaxanthin-loaded liposomes.

As regression testing size and cost increase,test suite reduction becomes more important to promote its efficiency.Du-ring the selection of test suite subset,we are supposed to consider the representativeness and diversity of subset,and apply an effective algorithm to solve it.Aimed at test suite reduction,a submodular function maximization based algorithm,SubTSR,is proposed in this paper.Although the introduced discrete optimization problem is an NP-hard problem,the heuristic greedy search is used in this paper to find the suboptimal solution with approximation guarantee by exploiting the submodularity of the objective function.To validate the effectiveness of the SubTSR algorithm,the SubTSR algorithm is experimented on fifteen datasets with changes of topic count in LDA and distance for similarity measurement,and compared with other test suite reduction algorithms about the average percentage of fault-detection,fault detection loss rate,first faulty test's index and other metrics.The experiment results show that the SubTSR algorithm has significant improvement in fault detection performance compared with other algorithms,and its performance remains relatively stable on different datasets.Under the text representation change due to topic count change,the SubTSR combined with Manhattan distance keeps relatively stable compared with other algorithms.

We demonstrate a simple, cost-effective method to enhance the photoluminescence intensity of monolayer MoS2. A hexagonal symmetric Au metasurface, made by polystyrene nanosphere lithography and metal coating, is developed to enhance the photoluminescence intensity of monolayer MoS2. By using nanospheres of different sizes, the localized surface plasmon resonances of the Au metasurfaces can be effectively tuned. By transferring monolayer MoS2 onto the Au metasurface, the photoluminescence signal of the monolayer MoS2 can be significantly enhanced up to 12-fold over a square-centimeter area. The simple, large-area, cost-effective fabrication technique could pave a new way for plasmon-enhanced light-mater interactions of atomically thin two-dimensional materials.