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Nanosecond pulsed dielectric barrier discharge (DBD) has great application prospects for in situ resource utilization (ISRU) on Mars. In the low-pressure environment similar to Mars' atmosphere, the characteristics of CO2 DBD driven by two different types of nanosecond pulsed power supplies were compared. Also, the effect of different system parameters on the discharge was studied through univariate experiments. The results showed that the discharge characteristics driven by different power supplies were significantly different, and different relationships between the energization conditions and discharge parameters were obtained: the current and deposited energy of a single discharge (occurring on either the rising or falling edge) increased with increasing voltage rise rate and decreased with increasing repetition frequency, but were irrelevant to plateau duration; increasing the voltage rise rate, decreasing the plateau duration and discharge gap, and proper gas flow rate all increased the single pulse energy.

In recent years, the field of unmanned aerial vehicle (UAV) tracking has grown rapidly, finding numerous applications across various industries. While the discriminative correlation filters (DCF)-based trackers remain the most efficient and widely used in the UAV tracking, recently lightweight convolutional neural network (CNN)-based trackers using filter pruning have also demonstrated impressive efficiency and precision. However, the performance of these lightweight CNN-based trackers is still far from satisfactory. In the generic visual tracking, emerging vision transformer (ViT)-based trackers have shown great success by using cross-attention instead of correlation operation, enabling more effective capturing of relationships between the target and the search image. But to best of the authors’ knowledge, the UAV tracking community has not yet well explored the potential of ViTs for more effective and efficient template-search coupling for UAV tracking. In this article, we propose an efficient ViT-based tracking framework for real-time UAV tracking. Our framework integrates feature learning and template-search coupling into an efficient one-stream ViT to avoid an extra heavy relation modeling module. However, we observe that it tends to weaken the target information through transformer blocks due to the significantly more background tokens. To address this problem, we propose to maximize the mutual information (MI) between the template image and its feature representation produced by the ViT. The proposed method is dubbed TATrack. In addition, to further enhance efficiency, we introduce a novel MI maximization-based knowledge distillation, which strikes a better trade-off between accuracy and efficiency. Exhaustive experiments on five benchmarks show that the proposed tracker achieves state-of-the-art performance in UAV tracking. Code is released at: https://github.com/xyyang317/TATrack.

The increase in the mechanical performance of Al-Cu alloys through TiC particle reinforcement represents a significant improvement in the field of aluminum alloy strengthening. However, the precipitation behavior at the aluminum matrix and TiC interface requires further exploration. In this study, the induced precipitation mechanisms at the TiC interface and the impact of interface precipitates on bonding were investigated through scanning transmission electron microscopy (STEM) and first-principles calculations. The results indicate that θ'-Al2Cu exhibits heterogeneous nucleation on the TiC substrate, and the (100) Al/(110) θ'-Al2Cu /(100) TiC interface structure possesses the lowest formation energy. Consequently, the precipitation of θ'-Al2Cu at the Al/TiC interface demonstrates thermodynamic preference and energy stability. Tensile simulations reveal that the presence of interface precipitates effectively enhances the strength of the interface structure. Electronic structure analysis indicates a “barrel effect” in the stretched interface model, with fracture occurring in the weakest-bonded Al lattice near the phase interface. Additionally, θ'-Al2Cu, acting as an interface adhesive, enhances the chemical bond strength between Al and TiC interface atoms. This work provides novel insights into particle-induced interface precipitation behavior and interface fracture mechanisms.

Cryogenic rolling is a promising method to improve the mechanical properties of Al–Mg–Si alloys. In this paper, the effect of artificial aging treatment on the mechanical properties and microstructures of cryogenic rolled Al–Mg–Si sheet is investigated. The hardness and yield strength of cryogenic rolled alloys decrease at the early aging stage, but the hardness and yield strength of room temperature rolled alloys increase at the early aging stage. Besides, substructures (such as dislocations) are observed in cryogenic rolled alloys but not in room temperature rolled alloys after solution treatment, the degree of recrystallization in the cryogenic rolled alloy is inferior to that in room temperature rolled alloy. The differences lead to the difference in strength between cryogenic rolled alloys and room temperature rolled alloys at the early aging stage. A precipitation mechanism is proposed to explain how these substructures promote precipitate nucleation and growth during artificial aging treatment. Based on the precipitation strengthening theory, a precipitation model is used to explain the strengthening contribution from precipitation during aging treatment, the capacity of precipitation strengthening in cryogenic rolled alloy is much higher than that in room temperature rolled alloy.

The negative hyperconjugation (NHC) of sp2and sp3hybrid nitrogen atoms were studied based on the calculation of quinoxaline derivatives containing piperazine moiety. The energy level, electronic density and spatial position of acceptor orbital are all important factors of NHC. NHC of nitrogen atom does not limit in the case that the σ*-acceptor orbital is in the anti-staggered positon of donor orbital, but it will switch off when nitrogen atom loses its lone pair electron. These results are proved by the crystal structure and the calculation of vibration frequencies. At last, two quinoxaline derivatives synthesized in this work show good anticancer activities against leukemia cell lines.

3D integration utilizing TSV (Through-Silicon Via) is a promising technology to achieve high performance 3DIC (three-dimentional integrated circuit), not only because it exponentially increases connection efficiency between dies, but also because it can be practically integrated into current IC manufacture processes with minimal impact on both FEOL and BEOL design and processing. During construction of TSV, CMP (Chemical-Mechanical Polishing) is required to reveal the vias and finish the wafer surface for future processing. Reported in this paper is our recent effort in developing a series of slurries for TSV front-side polishing by close collaboration in device design, slurry formulation and process fine-tuning. Specifically, high through-put and well performed Cu slurries, along with high SiO2/Si3N4 selectivity barrier slurries, are introduced. These slurries are tested on laboratory-scale instruments as well as foundry CMP tools. Polishing results from both blanket and pattern wafers are discussed.

Based on the detection method of optical inspection tool, an in-situ Cu residue detection method was developed to check all the wafers through the optical endpoint system. This method will help to block the wafer which suffered Cu residue defect flowing to the next process step and monitor the hardware variation, consumable variation and process variation. It will also help to improve manufacture efficiency

In this paper, a silicon CMP process has been developed inside semiconductor fabrication to reclaim bare silicon wafers for cost and time reductions. Firstly, the high level defect after CMP was encountered and mainly particle; after related polishing and cleaning processes were optimized, the defect count was much reduced but still higher than the specification; finally, the defect count was dramatically decreased and met the specification by adding a surfactant (TMAH) in polishing. The effect of surfactant on defect reduction is also discussed in this paper.

Cold ^87Rb atom's loading in an integrating sphere with diffuse light is analyzed theoretically and experimentally. The experimental results show that diffuse light cooling has the greatest efficiency to cool the most atoms when the red detuning between the frequencies of cooling light and atom transition is about 3.3\Γ (Γ is the natural linewidth, 6.065 MHz). Theoretical analysis using rate equation and numerical calculations on the cold atom number and loading time agree with the experimental results. This integrating sphere cooling would be a novel method for cooling atoms and lead to a new and robust cold atom source for atomic clock.

To follow the Moore’s law, the advanced Cu slurry needs to continue the trend of cost reduction and performance improvement at the same time. With the technology node shrinking, there is a need to develop a Cu slurry with fast rate for high throughput and low dishing for minimal within die and within wafer variation, and stringent defect requirement such as residue, corrosion, and micro scratches. In this paper, we introduce a high performance Cu CMP slurry to overcome these performance challenges in Cu CMP process. The impact of slurry formulation on the slurry performance will be presented under different process conditions, including blanket removal rates/profiles, static etch rates, dishing, Cu residue clearance capability and corrosion status. Electrochemical study was also conducted to support the results and performance. With the optimized formulation and polishing process, the slurry achieves dishing under 300A at near 1 um Cu polishing rate. For multiple layers stacking, the slurry also has tunable dishing to provide a wide process integration window.

Backside illumination (BSI) is an uprising technology to achieve high performance of CMOS (Complementary Metal-Oxide Semiconductor) imaging. Si CMP (Chemical-Mechanical Polishing) process is required in BSI application to remove grinding masks and dislocations from bonded wafer with typical 1.0~3.0um removal amount. BSI CMP appears easy compared to traditional IC CMP in that there is much less integration requirements from pre/post CMP steps. The challenges lie in CMP profile control to compensate incoming thickness variation from grinding for low TTV (total thickness variation), low surface roughness and supreme surface quality for optical path, and low cost for mass production. There is a need to develop slurries/process to conquer all the challenges. Reported in this paper is our recent effort to address such challenges in Si CMP process for BSI application by combining CMP slurry selection and process optimization together. The performances of these approaches were tested on laboratory-scale instruments and further optimized on 8” and 12” CMP tools. Polishing results from both blanket Si (EPI) wafers and SOI wafers are discussed to set up the final process conditions.

The Ramsey fringe contrast of a pulsed optically pumped cold atom clock is strongly affected by the transverse decay of the atomic sample. This letter calculates the Ramsey fringe with focus on transverse decay, and analyzes the Ramsey fringe contrast with different transverse decay rates. By fitting the experimental data, we obtain the transverse decay rate in a cold atom sample at an approximate value of 30.5 s^-1, which is much smaller than that in a cell.

We cool ^85Rb atoms in an integrating sphere directly from a vapor background using diffuse light generated by multiple reflections of laser beams in the inner surface of the integrating sphere. We compare and analyze the different features of cold ^85Rb atoms and cold ^87Rb atoms in diffuse light cooling, which are important in applying ^85Rb and ^87Rb isotopes in many experiments on testing fundamental physics.

3D integration utilizing TSV (Through-Silicon Via) is a promising technology to achieve high performance 3DIC (three-dimentional integrated circuit), not only because it exponentially increases connection efficiency between dies, but also because it can be practically integrated into current IC manufacture processes with minimal impact on both FEOL and BEOL design and processing. During construction of TSV, CMP (Chemical-Mechanical Polishing) is required to reveal the vias and finish the wafer surface for future processing. Reported in this paper is our recent effort in developing a series of slurries for TSV front-side polishing by close collaboration in device design, slurry formulation and process fine-tuning. Specifically, high through-put and well performed Cu slurries, along with high SiO2/Si3N4 selectivity barrier slurries, are introduced. These slurries are tested on laboratory-scale instruments as well as foundry CMP tools. Polishing results from both blanket and pattern wafers are discussed.

Based on the detection method of optical inspection tool, an in-situ Cu residue detection method was developed to check all the wafers through the optical endpoint system. This method will help to block the wafer which suffered Cu residue defect flowing to the next process step and monitor the hardware variation, consumable variation and process variation. It will also help to improve manufacture efficiency

In this paper, a silicon CMP process has been developed inside semiconductor fabrication to reclaim bare silicon wafers for cost and time reductions. Firstly, the high level defect after CMP was encountered and mainly particle; after related polishing and cleaning processes were optimized, the defect count was much reduced but still higher than the specification; finally, the defect count was dramatically decreased and met the specification by adding a surfactant (TMAH) in polishing. The effect of surfactant on defect reduction is also discussed in this paper.