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Vacancy healing for stable perovskite solar cells via bifunctional potassium tartrate

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Journal of Energy Chemistry 2024年第1期88卷 64-70,I0002页

作者： Jing dou Yue Ma Xiuxiu Niu Wentao Zhou Xueyuan Wei Jie dou Zhenhua Cui Qizhen Song tinglu Song Huanping Zhou Cheng Zhu Yang Bai Qi Chen Experimental Centre for Advanced Materials School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China Beijing Key Laboratory for Theory and Technology of Advanced Battery Materials Key Laboratory of Polymer Chemistry and Physics of Ministry of EducationBIC-ESATSchool of Materials Science and EngineeringPeking UniversityBeijing 100871China

Perovskite solar cell has gained widespread attention as a promising technology for renewable ***, their commercial viability has been hampered by their long-term stability and potential Pb leakage. Herein, we demonstrate a bifunctional passivator of the potassium tartrate(PT) to address both challenges. PT minimizes the Pb leakage in perovskites and also heals cationic vacancy defects, resulting in improved device performance and stability. Benefiting from PT modification, the power conversion efficiency(PCE) is improved to 23.26% and the Pb leakage in unencapsulated films is significantly reduced to 9.79 ppm. Furthermore, the corresponding device exhibits no significant decay in PCE after tracking at the maximum power point(MPP) for 2000 h under illumination(LED source, 100 mW cm^(-2)).

关键词： Perovskite Potassium tartrate Lead leakage Long-term stability

High-Precision DOA Estimation Method Based on Synthetic Aperture Technique

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Journal of Beijing Institute of Technology 2024年第2期33卷 111-118页

作者： Yongjia dou Guangcai Sun Yuqi Wang Mengdao Xing National Key Laboratory of Radar Signal Processing Xidian UniversityXi’an 710071China School of Communication and Information Engineering Xi’an University of Science and TechnologyXi’an 710054China

The existing direction-of-arrival(DOA)estimation methods only utilize the current received signals,which are susceptible to *** this paper,a method for DOA estimation based on a motion platform is proposed to achieve high-precision DOA estimation by utilizing past and present *** concept of synthetic aperture is introduced to construct a linear DOA estima-tion model.A DOA fine-tuning method based on the linear model is proposed to eliminate the lin-ear DOA variation,achieving a non-coherent accumulation of DOA ***,the baseband modulation and the phase modulation caused by the range history are compensated to achieve the coherent accumulation of all the DOA *** results show that the proposed method can significantly improve the DOA estimated accuracy at low signal-to-noise ratios(SNR).

关键词： synthetic aperture direction-of-arrival(DOA)estimation coherent accumulation

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Operational requirements analysis method based on question answering of WEKG

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Journal of Systems Engineering and Electronics 2024年第2期35卷 386-395页

作者： ZHANG Zhiwei dou Yajie XU Xiangqian MA Yufeng JIANG Jiang TAN Yuejin College of Systems Engineering National University of Defense TechnologyChangsha 410073China

The weapon and equipment operational requirement analysis(WEORA) is a necessary condition to win a future war,among which the acquisition of knowledge about weapons and equipment is a great challenge. The main challenge is that the existing weapons and equipment data fails to carry out structured knowledge representation, and knowledge navigation based on natural language cannot efficiently support the WEORA. To solve above problem, this research proposes a method based on question answering(QA) of weapons and equipment knowledge graph(WEKG) to construct and navigate the knowledge related to weapons and equipment in the WEORA. This method firstly constructs the WEKG, and builds a neutral network-based QA system over the WEKG by means of semantic parsing for knowledge navigation. Finally, the method is evaluated and a chatbot on the QA system is developed for the WEORA. Our proposed method has good performance in the accuracy and efficiency of searching target knowledge, and can well assist the WEORA.

关键词： operational requirement analysis weapons and equipment knowledge graph(WEKG) question answering(QA) neutral network

Numerical analysis on seismic response and failure mechanism of articulated pile−structure system in a liquefiable site from shaking-table experiments

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Frontiers of Structural and Civil Engineering 2024年第7期18卷 1117-1133页

作者： Pengfei dou Hao LIU Chengshun XU Jinting WANG Yilong SUN Xiuli DU Department of Hydraulic Engineering Tsinghua UniversityBeijing 100084China Key Laboratory of Urban Security and Disaster Engineering of the Ministry of Education Beijing University of TechnologyBeijing 100124China

This study investigates the seismic response and failure mode of a pile-structure system in a liquefiable site by employing a numerical simulation model combined with the shaking-table results of a soil-pile-structure dynamic *** pile and soil responses obtained from the numerical simulations agreed well with the experimental *** slopes of the dynamic shear-stress-shear-strain hysteretic curves at different positions also exhibited a decreasing trend,indicating that the shear strength of the soil in all parts of the foundation *** peak acceleration of the soil and pile was not clearly amplified in the saturated sand layer but appeared to be amplified in the top *** maximum bending moments appeared in the middle and lower parts of the pile shaft;however,the shear forces at the corresponding positions were not *** can be observed from the deformation mode of the pile-group foundation that a typical bending failure is caused by an excessive bending moment in the middle of the pile shaft if the link between the pile top and cap is articulated,and sufficient attention should be paid to the bending failure in the middle of the pile shaft.

关键词： numerical simulation soil liquefaction pile foundation shaking-table experiment seismic responses failure model

Assessment of International GNSS Service Global Ionosphere Map products over China region based on measurements from the Crustal Movement Observation Network of China

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Earth and Planetary Physics 2024年第2期8卷 400-407页

作者： Jin Hu HaiBing Ruan FuQing Huang ShengYang Gu XianKang dou Institute of Space Weather Nanjing University of Information Science and TechnologyNanjing 210044China State Key Laboratory of Space Weather Chinese Academy of Sciences(CAS)Beijing 100190China School of Electronic Information Wuhan UniversityWuhan 430072China Wuxi Research Institute Nanjing University of Information Science and TechnologyWuxi Jiangsu 214000China CAS Key Laboratory of Geospace Environment School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China

The global ionosphere maps(GIM)provided by the International GNSS Service(IGS)are extensively utilized for ionospheric morphology monitoring,scientific research,and practical *** the credibility of GIM products in data-sparse regions is of paramount *** this study,measurements from the Crustal Movement Observation Network of China(CMONOC)are leveraged to evaluate the suitability of IGS-GIM products over China region in *** indices of mean error(ME),root mean square error(RMSE),and normalized RMSE(NRMSE)are then utilized to quantify the accuracy of IGS-GIM *** revealed distinct local time and latitudinal dependencies in IGS-GIM errors,with substantially high errors at nighttime(NRMSE:39%)and above 40°latitude(NRMSE:49%).Seasonal differences also emerged,with larger equinoctial deviations(NRMSE:33.5%)compared with summer(20%).A preliminary analysis implied that the irregular assimilation of sparse IGS observations,compounded by China’s distinct geomagnetic topology,may manifest as error *** results suggest that modeling based solely on IGS-GIM observations engenders inadequate representations across China and that a thorough examination would proffer the necessary foundation for advancing regional total electron content(TEC)constructions.

关键词： International GNSS Service(IGS)Global Ionosphere Maps(GIM) Crustal Movement Observation Network of China(CMONOC) total electron content(TEC) data assessment

Ballistic performance of spherical fragments penetrating PCrNi3MoV target plates

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Defence Technology（防务技术） 2024年第3期33卷 295-307页

作者： dou Hong Wenbin Li Yu Zheng Yiming Li Ning Jiang Kebin Zhang Ministerial Key Laboratory of ZNDY Nanjing University of Science and TechnologyNanjingChina

PCrNi3MoV steel is a medium-carbon,low-alloy quenched and tempered steel that finds its applications in military gun barrels due to the high wear resistance and ablation *** study the penetration and failure modes of PCrNi3MoV plates impacted by tungsten spheres,tungsten spheres of various diameters(5 mm,8 mm,and 10 mm)were used to impact PCrNi3MoV steel plates with thicknesses of 6 mm,9 mm,and 14 *** penetration performance of the spheres was analyzed for different velocities,and the ultimate penetration velocity of the plate was *** was found that the primary failure modes of the PCrNi3MoV plate were compression pitting failure and shear *** the dimensional analysis method,a relationship between the bulge height of the steel plate and the fragment velocity,an equation for the ultimate penetration velocity,and a relationship between the target penetration energy and the fragment velocity were ***,a projectile-target action index was proposed to describe the process of tungsten spheres with different velocities impacting target *** results suggested that under the same thickness of the target plate,a larger-diameter fragment required more kinetic energy to obtain the same ultimate penetration effect as a smaller-diameter *** equations obtained through dimensional analysis predicted values that agreed well with experimental values,indicating that these equations can be applied to engineering applications.

关键词： Impact damage Ultimate penetration velocity Bulge height Target penetration energy Failure modes

Nano-sized stationary phase packings retained by single-particle frit for microchip liquid chromatography

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Chinese Chemical Letters 2024年第4期35卷 486-489页

作者： Wangyan Hu Ke Li Xiangnan dou Ning Li Xiayan Wang Center Excellence for Environmental Safety and Biological Effects Beijing Key Laboratory for Green Catalysis and SeparationDepartment of ChemistryBeijing University of TechnologyBeijing 100124China Center for Environmental Metrology National Institute of MetrologyBeijing 100029China

Modern chromatography is increasingly focused on miniaturization and integration. Compared to conventional liquid chromatography, microfluidic chip liquid chromatography(microchip-LC) has the potential due to its zero-dead volume connection and ease of integration. Nano-sized packings have the potential to significantly enhance separation performance in microchip-LC. However, their application has been hindered by packing difficulties. This study presents a method for packing nano-sized silica particles into a microchannel as the stationary phase. The microchip-LC packed column was prepared by combining the weir and the porous silica single-particle as frit to retain the packing particles. A surface tensionbased single-particle picking technique was established to insert porous single-particle frit into glass microchannels. Additionally, we developed a slurry packing method that utilizes air pressure to inject nano-sized packing into the microchannel. Pressure-driven chromatographic separation was performed using this nano-packed column integrated into a glass microchip. The mixture of four PAHs was successfully separated within just 8 min using a 5 mm separation channel length, achieving high theoretical plates(10~6plates/m). Overall, these findings demonstrate the potential of utilizing nano-sized packings for enhancing chromatographic performance in microchip systems.

关键词： Nano-size packing Single-particle frit Packed column Microchip LC Chromatographic separation

Large Deviations for a Critical Galton-Watson Branching Process

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Acta Mathematicae Applicatae Sinica 2024年

作者： dou-dou LI Wan-lin SHI Mei ZHANG College of Statistics and Data Science Faculty of Science Beijing University of Technology Laboratory of Mathematics and Complex Systems (Ministry of Education) School of Mathematical SciencesBeijing Normal University Department of Mathematics and Physics North China Electric Power University

In this paper, a critical Galton-Watson branching process{Zn}is considered. Large deviation rates of SZn:=∑i=1ZnXiare obtained, where{Xi, i≥1}is a sequence of independent and identically distributed random variables and X1is in the domain of attraction of an α-stable law with α∈(0, 2). One shall see that the convergence rate is determined by the tail index of X1and the variance of Z1. Our results can be compared with those ones of the supercritical case.

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Cobalt-nanoparticle catalysts derived from zeolitic imidazolate framework@MXene composites for efficient oxidative self-coupling of benzylamines

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Frontiers of Chemical Science and Engineering 2024年第1期18卷 95-106页

作者： Jie Chen Mingyuan Jian Deqiong Xie Kecan dou Deli Chen Weidong Zhu Fumin Zhang Key Laboratory of the Ministry of Education for Advanced Catalysis Materials Institute of Physical ChemistryZhejiang Normal UniversityJinhua 321004China

In this study,we synthesize a catalyst comprising cobalt nanoparticles supported on MXene by pyrolyzing a composite in a N2 ***,the composite comprises a bimetallic Zn/Co zeolitic imidazole framework grown in situ on the outer surface of *** catalytic efficiency of the catalyst is tested for the self-coupling of 4-methoxybenzylamine to produce value-added imine,where atmospheric oxygen(1 atm)is used as the *** on the results,the catalyst displayed impressive catalytic activity,achieving 95.4%yield of the desired imine at 383 K for 8 ***,the catalyst showed recyclability and tolerance toward benzylamine substrates with various functional *** outstanding performance of the catalyst is primarily attributed to the synergetic catalytic effect between the cobalt nanoparticles and MXene support,while also benefiting from the three-dimensional porous ***,a preliminary investigation of potential reaction mechanisms is conducted.

关键词： MXene sacrificial template oxidative self-coupling Co nanoparticles imine