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Recent progresses in thermal treatment of β-Ga_(2)O_(3) single crystals and devices

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International Journal of Minerals,Metallurgy and Materials 2024年第7期31卷 1659-1677页

作者： yuchao Yan Zhu Jin Hui Zhang Deren Yang State Key Laboratory of Silicon and Advanced Semiconductor Materials and School of Materials Science and Engineering Zhejiang UniversityHangzhou 310027China Zhejiang Provincial Key Laboratory of Power Semiconductor Materials and Devices ZJU-Hangzhou Global Scientific and Technological Innovation CenterHangzhou 311200China

In recent years,ultra-wide bandgap β-Ga_(2)O_(3) has emerged as a fascinating semiconductor material due to its great potential in power and photoelectric devices.In semiconductor industrial,thermal treatment has been widely utilized as a convenient and effective approach for substrate property modulation and device fabrication.Thus,a thorough summary of β-Ga_(2)O_(3) substrates and devices behaviors after high-temperature treatment should be significant.In this review,we present the recent advances in modulating properties of β-Ga_(2)O_(3) substrates by thermal treatment,which include three major applications:(ⅰ)tuning surface electrical properties,(ⅱ)modifying surface morphology,and(ⅲ)oxidating films.Meanwhile,regulating electrical contacts and handling with radiation damage and ion implantation have also been discussed in device fabrication.In each category,universal annealing conditions were speculated to figure out the corresponding problems,and some unsolved questions were proposed clearly.This review could construct a systematic thermal treatment strategy for various purposes and applications of β-Ga_(2)O_(3).

关键词： β-gallium oxide thermal treatment substrates devices

Could natural phytochemicals be used to reduce nitrogen excretion and excreta‑derived N_(2)O emissions from ruminants?

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Journal of Animal Science and Biotechnology 2024年第2期15卷 490-508页

作者： yuchao Zhao Ming Liu Linshu Jiang Leluo Guan Beijing Key Laboratory of Dairy Cow Nutrition College of Animal Science and TechnologyBeijing University of AgricultureBeijing 102206China College of Animal Science and Technology China Agricultural UniversityBeijing 100193China Department of Agricultural Food and Nutritional ScienceUniversity of AlbertaEdmontonAB T6G 2R3Canada

Ruminants play a critical role in our food system by converting plant biomass that humans cannot or choose not to consume into edible high-quality food.However,ruminant excreta is a significant source of nitrous oxide(N_(2)O),a potent greenhouse gas with a long-term global warming potential 298 times that of carbon dioxide.Natural phytochemicals or forages containing phytochemicals have shown the potential to improve the efficiency of nitrogen(N)utilization and decrease N_(2)O emissions from the excreta of ruminants.Dietary inclusion of tannins can shift more of the excreted N to the feces,alter the urinary N composition and consequently reduce N_(2)O emissions from excreta.Essential oils or saponins could inhibit rumen ammonia production and decrease urinary N excretion.In grazed pastures,large amounts of glucosinolates or aucubin can be introduced into pasture soils when animals consume plants rich in these compounds and then excrete them or their metabolites in the urine or feces.If inhibitory compounds are excreted in the urine,they would be directly applied to the urine patch to reduce nitrification and subsequent N_(2)O emissions.The phytochemicals’role in sustainable ruminant production is undeniable,but much uncertainty remains.Inconsistency,transient effects,and adverse effects limit the effectiveness of these phytochemicals for reducing N losses.In this review,we will identify some current phytochemicals found in feed that have the potential to manipulate ruminant N excretion or mitigate N_(2)O production and deliberate the challenges and opportunities associated with using phytochemicals or forages rich in phytochemicals as dietary strategies for reducing N excretion and excreta-derived N_(2)O emissions.

关键词： Nitrogen metabolism Nitrous oxide Plant bioactive compounds Ruminant Urine patches

Analytical evaluation of steady-state solute distribution in through- diffusion and membrane behavior test under non-perfectly flushing boundary conditions

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第1期16卷 258-267页

作者： Guannian Chen yuchao Li Kristin MSample-Lord Shan Tong School of Civil&Environmental Engineering and Geography Science Ningbo UniversityNingbo315211China MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering College of Civil Engineering and ArchitectureZhejiang UniversityHangzhou310058China Ningbo ZCONE High-tech Company Limited Ningbo315000China Department of Civil and Environmental Engineering Villanova UniversityVillanovaPAUSA

The through-diffusion and membrane behavior testing procedure using a closed-system apparatus has been widely used for concurrent measurement of diffusion and membrane efficiency coefficients of low-permeability clay-based barrier materials.However,the common assumption of perfectly flushing conditions at the specimen boundaries could induce errors in analyses of the diffusion coefficients and membrane efficiencies.In this study,an innovative pseudo three-dimensional(3D)analytical method was proposed to evaluate solute distribution along the boundary surfaces of the soil-porous disks system,considering the non-perfectly flushing conditions.The results were consistent with numerical models under two scenarios considering different inflow/outflow positions.The proposed model has been demonstrated to be an accurate and reliable method to estimate solute distributions along the bound-aries.The calculated membrane efficiency coefficient and diffusion coefficient based on the proposed analytical method are more accurate,resulting in up to 50%less relative error than the traditional approach that adopts the arithmetic mean value of the influent and effluent concentrations.The retar-dation factor of the clay specimen also can be calculated with a revised cumulative mass approach.Finally,the simulated transient solute transport matched with experimental data from a multi-stage through-diffusion and membrane behavior test,validating the accuracy of the proposed method.

关键词： Diffusion testing Membrane behavior Coupled transport Clay barrier Transport modeling

A Tale of Two“Skewness”:Managerial Epidemic Experience,Probability Weighting and Financial Market Stability

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Social Sciences in China 2024年第1期45卷 157-181页

作者： Gu Leilei Ni Xiaoran Peng yuchao Business School Central University of Finance and Economics School of Economics Xiamen University School of Finance and Belt&Road Finance Institute Central University of Finance and Economics

Under probability weighting,entrepreneurs with skewness preference tend to seek rightskewed and avoid left-skewed risks.We show that Chinese firms managed by CEOs with professional epidemic experience,i.e.,who previously experienced the outbreak of SARS during their tenure as high level executives,have a lower stock price crash risk measured by the negative skewness of stock prices in subsequent periods.In particular,those firms intentionally avoid stock price crashes by adopting more conservative strategies in decisionmaking.Overall,we provide the first evidence on the unintended effect of entrepreneurs'subjective judgments of the probabilities of disease outbreaks on financial market stability.These have long-term implications for the financial system.

关键词： SARS epidemic experience probability weighting skewness preference stock price crash risk

Proximal Linearized Minimization Algorithm for Nonsmooth Nonconvex Minimization Problems in Image Deblurring with Impulse Noise

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Journal of Mathematical Research with Applications 2024年第1期44卷 122-142页

作者： Shirong DENG yuchao TANG School of Mathematics and Information Science Guangzhou University Department of Mathematics Nanchang University

Impulse noise removal is an important task in image restoration. In this paper, we introduce a general nonsmooth nonconvex model for recovering images degraded by blur and impulsive noise, which can easily include some prior information, such as box constraint or low rank, etc. To deal with the nonconvex problem, we employ the proximal linearized minimization algorithm. For the subproblem, we use the alternating direction method of multipliers to solve it. Furthermore, based on the assumption that the objective function satisfies the KurdykaLojasiewicz property, we prove the global convergence of the proposed algorithm. Numerical experiments demonstrate that our method outperforms both the l1TV and Nonconvex TV models in terms of subjective and objective quality measurements.

关键词： nonconvex data fidelity term impulse noise total variation proximal linearized minimization

The response and anti-stress mechanisms of nitrifying sludge under long-term exposure to Cd Se quantum dots

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Journal of Environmental Sciences 2024年第1期135卷 174-184页

作者： Linkai Guo Lei Yang Yongxiang Ren Shen Cui Xiaotong Li Jia Wang Jun Lan Haoqi Lu yuchao Wang Shaanxi Key Laboratory of Environmental Engineering Xi’an University of Architecture and TechnologyXi’an 710055China Key Lab of Northwest Water Resource Environment and EcologyMinistry of EducationXi’an University of Architecture and TechnologyXi’an 710055China

The wide application of CdSe quantum dots(QDs)increases its stress risk to sewage treatment systems.This study evaluated the response of nitrification performance,floc characteristics and microbial community of nitrifying sludge under long-term exposure to CdSe QDs.Results showed CdSe QDs(≥1 mg/L)would decrease the activity of ammonia monooxygenase(AMO).Under the stress of 30 mg/L CdSe QDs,the activity of AMO was reduced by 66%,while the activities of hydroxylamine oxidase and nitrite oxidoreductase were enhanced by 19.1%and 26%,respectively.Thus,the final nitrification effects were not adversely affected,and the production rates of NO_(2)^(-)-N and NO_(3)^(-)-N were accelerated.Additionally,CdSe QDs improved biomass concentration in sludge and maintained the stability of sludge settleability.High throughput sequencing analysis showed that CdSe QDs evidently reduced the abundance and diversity of microbial community in nitrifying sludge.The abundances of amino acid metabolism and lipid metabolism were enriched.Moreover,CdSe QDs decreased the fluorescence intensity of tryptophan-like protein from 2,326 to 1,179 a.***.in loosely bound extracellular polymeric substances(EPSs)and from 3,792 to 3,117 a.***.in tightly bound EPSs.To relieve CdSe QD stress,the polysaccharide content increased from0.31 to 0.61 mg/g MLSS and intracellular antioxidant defense was activated.With CdSe QD level increasing to 30 mg/L,the total antioxygenic capacity and the activities of catalase were enhanced up to 411%and 143.2%,respectively.Thereby,CdSe QDs had little adverse effects on cell membrane integrity,microbial metabolism and the abundance of Nitrospirae.

关键词： Quantum dots Activated sludge Extracellular polymeric substances Microbial community Antioxidant effect

supersaturation-driven self-assembly formation of ceftriaxone sodium spherulites:From amorphous form to spherulites

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Particuology 2024年第7期90卷 10-19页

作者： Shankun Liang yuchao Niu Xueyan Hu Wu Xiao Xuehua Ruan Gaohong He Xiaobin Jiang State Key Laboratory of Fine Chemicals Frontiers Science Center for Smart MaterialsSchool of Chemical EngineeringDalian University of TechnologyDalian116024China School of Chemical Engineering at Panjin Dalian University of TechnologyPanjin124221China

Drug particles with spherical morphology possess amazing advantages in terms of particle flowability,mechanical properties,drug solubility,and bioavailability.The growth mechanism of drug spherulite is of great importance for the preparation and regulation of spherulites.Herein,ceftriaxone sodium spherulites were fabricated by the antisolvent crystallization method using dropwise addition of ceftriaxone sodium solution to acetone.Online observation of the whole crystallization process combined with electron microscopy technique revealed the spherical growth process from amorphous form to spherulites.As the supersaturation of the crystallization system was adjusted,the ceftriaxone sodium crystals transformed from amorphous form to spherulites.In the process of antisolvent crystallization with acetone as antisolvent,when the theoretical supersaturation degree S was higher than 2.62,the crystallization system tended to appear amorphous form;when S was between 2.57 and 2.62,the amorphous form transformed into clustered spherulites;when S was less than 2.57,the surface of spherulites will be covered with flaky crystal,which transformed into urchin-like type.With the understanding of the spherical growth mechanism,the ceftriaxone sodium spherulites prepared in this research with modified supersaturation control had a low residue of antisolvent acetone,and the flowability was significantly improved.

关键词： Spherulite Ceftriaxone sodium Antisolvent crystallization supersaturation Online observation

Early chatter identification based on optimized VMD with multi-band information fusion and compression method in robotic milling process

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Chinese Journal of Aeronautics 2024年第6期37卷 464-484页

作者： Sichen CHEN Zhiqiang LIANG yuchao DU Zirui GAO Haoran ZHENG Zhibing LIU Tianyang QIU Xibin WANG School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing 401120China

Undesirable self-excited chatter has always been a typical issue restricting the improvement of robotic milling quality and efficiency.Sensitive chatter identification based on processing signals can prompt operators to adjust the machining process and prevent chatter damage.Compared with the traditional machine tool,the uncertain multiple chatter frequency bands and the band-moving of the chatter frequency in robotic milling process make it more challenging to extract chatter information.This paper proposes a novel method of chatter identification using optimized variational mode decomposition(OVMD)with multi-band information fusion and compression technology(MT).During the robotic milling process,the number of decomposed modes k and the penalty coefficient a are optimized based on the dominant component of frequency scope partition and fitness of the mode center frequency.Moreover,the mayfly optimization algorithm(MA)is employed to obtain the global optimal parameter selection.In order to conquer information collection about the uncertain multiple chatter frequency bands and the band-moving of the chatter frequency in robotic milling process,MT is presented to reduce computation and extract signal characteristics.Finally,the cross entropy of the image(CEI)is proposed as the final chatter indicator to identify the chatter occurrence.The robotic milling experiments are carried out to verify the proposed method,and the results show that it can distinguish the robotic milling condition by extracting the uncertain multiple chatter frequency bands and overcome the band-moving of the chatter frequency in robotic milling process.

关键词： Robotic milling Chatter detection Variational mode decomposition Information fusion and compression Chatter featur

Bias distribution and regulation in photoelectrochemical overall water-splitting cells

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National Science Review 2024年第4期11卷 141-150页

作者： Kun Dang Siqin Liu Lei Wu Daojian Tang Jing Xue Jiaming Wang Hongwei Ji Chuncheng Chen yuchao Zhang Jincai Zhao Key Laboratory of Photochemistry CAS ResearchEducation Center for Excellence in Molecular Sciences Institute of Chemistry Chinese Academy of Sciences University of Chinese Academy of Sciences

The water oxidation half-reaction at anodes is always considered the rate-limiting step of overall water splitting（OWS）,but the actual bias distribution between photoanodes and cathodes of photoelectro chemical（PEC） OWS cells has not been investigated systematically.In this work,we find that,for PEC cells consisting of photoanodes（nickel-modified n-Si [Ni/n-Si] and α-Fe2O3） with low photovoltage(Vph 1V,the bias required for cathode activation can be significantly reduced,exhibiting a kinetics-controlled characteristic.Further investigations show that the bias distribution can be regulated by tuning the electrolyte pH and using alternative half-reaction couplings.Accordingly,a volcano plot is presented for the rational design of the overall reactions and unbiased PEC cells.Motivated by this,an unbiased PEC cell consisting of a simple Ni/n-Si photoanode and Pt cathode is assembled,delivering a photo current density of 5.3±0.2 mA cm-2.

关键词： photoelectrochemistry overall reaction cell bias distribution photoanode water splitting