检索结果-南通市图书馆

同方期刊数据库

Recent progress in single crystal perovskite X-ray detectors

在线全文

学校读者我要写书评

暂无评论

Science China(information Sciences) 2024年第3期67卷 5-19页

作者： Xiao LIU Jun REN Yu-Ang CHEN Xiangshun GENG Dan XIE Tian-Ling REN School of Integrated Circuits Tsinghua University Beijing National research center for information Science and Technology (BNRist)

Perovskites have attracted extensive attention as radiation detection material due to their long carrier diffusion length and lifetime, high absorption coefficient, and flexible manufacturing process. Compared with polycrystalline structures, single crystal perovskites improve the performance of optoelectronic devices due to their low defect state density, better photoelectric characteristics, and chemical ***, we review the recent progress of single crystal perovskite X-ray detectors. First, we briefly introduced the basic concepts, detection mechanisms, figure of merits of perovskite X-ray detectors, and the preparation methods of single crystal perovskites. Then, we summarized the significant advancements in single crystal perovskite X-ray detectors in recent times. Finally, we discussed the critical challenges and some practicable solutions for developing high-performance X-ray detectors.

关键词： single crystal perovskites carrier transport radiation detection X-ray detectors X-ray imaging

Geometry characteristics and wide temperature behavior of silicon-based GaN surface acoustic wave resonators with ultrahigh quality factor

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(information Sciences) 2024年第2期67卷 267-278页

作者： Guofang YU Renrong LIANG Haiming ZHAO Lei XIAO Jie CUI Yue ZHAO Wenpu CUI Jing WANG Jun XU Jun FU Tianling REN School of Integrated Circuits Tsinghua University Beijing National research center for information Science Technology Tsinghua University

Surface acoustic wave(SAW) resonators with an ultrahigh Q-factor are designed and fabricated on silicon-based gallium nitride(GaN/Si). The temperature-dependent performance is characterized over a wide range, from 10 to 500 K. Finite element analysis is employed to guide the design of the SAW resonator from indications of the Rayleigh mode and weak propagation direction dependence of SAW in the c-plane of GaN/Si. The SAW resonator with 100 pairs of interdigital transducers(IDT), 100 pairs of grating reflectors(GR) for each side, aperture size of 80 μm, metallization ratio of 0.5, and electrode width of 500 nm resonates at 1.9133 GHz accordingly with an ultrahigh Q-factor of 7622 at room temperature, which contributes the fr× Qr, up to 14.583×1012Hz. A resonator operating over 10 to 500 K indicates an approximately linear decreasing temperature dependence above 280 K while being approximately constant below 40 K. The fitting to resonator characteristics using the modified Butterworth Van Dyke(m BVD) model reveals a reduction in both the electrode and mechanical losses while worsening the dielectric loss with cooling down.

关键词： GaN/Si SAW resonator ultrahigh Q-factor temperature-dependent performance mBVD losses

genome-wide CRISPR screening reveals key genes and pathways associated with 20-hydroxyecdysone signal transduction in the silkworm(Bombyx mori)

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Insect Science 2024年第1期31卷 47-58页

作者： Hao Sun Jingya Chen Ruolin Wang Dan Liu Na Zhang Tong Zhang Ling Jia Sanyuan Ma Qingyou Xia State Key Laboratory of Silkworm genome Biology Southwest UniversityChongqingChina Biological Science research center Southwest UniversityChongqingChina

Metamorphosis is a complex developmental process involving multiple pathways and a large number of genes that are regulated by juvenile hormone(JH)and 20-hydroxyecdysone(20E).Despite important progress in understanding various aspects of silkworm biology,the hormone signaling pathway in the silkworm remains poorly ***-wide screening using clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-associated protein 9(Cas9)-based libraries has recently emerged as a novel method for analyzing genome function,enabling further research into essential genes,drug targets,and virus-host ***,we constructed a genome-wide CRISPR/Cas9-based library of the silkworm(Bombyx mori)and successfully revealed the genes involved in biotic or abiotic stress factor *** this study,we used our silkworm CRISPR library and large-scale genome-wide screening to analyze the key genes in the silkworm 20E signaling pathway and their mechanisms of *** annotation showed that 20E regulates key proteins in processes that mainly occur in the cytoplasm and *** enrichment analysis showed that 20E can activate phosphorylation and may affect innate immunity,interfere with intracellular nutrition and energy metabolism,and eventually cause cell *** screening results were experimentally validated by generating cells with knockout alleles of the relevant genes,which had increased tolerance to *** findings provide a panoramic overview of signaling in response to 20E in the silkworm,underscoring the utility of genome-wide CRISPR mutant libraries in deciphering hormone signaling pathways and the mechanisms that regulate metamorphosis in insects.

关键词： CRISPR/Cas9 CRISPR library screening ecdysone 20E signal transduction silkworm whole genome editing

Multi-performance evaluation of high-throughput accelerated corrosion test for high-strength low-alloy 921A steel

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel research(International) 2024年第5期31卷 1260-1278页

作者： Cong-cong Du Ming-hua Qin Zhan-fang Wu Dong-ling Li Lei Zhao Xiang-yang Li Hai-zhou Wang Beijing Advanced Innovation center for Materials genome Engineering National Center for Materials Service SafetyUniversity of Science and Technology BeijingBeijing100083China China Iron and Steel research Institute Group Co. Ltd.Beijing100081China Beijing Advanced Innovation center for Materials genome Engineering Central Iron and Steel Research InstituteBeijing100081China

The corrosion behavior of high-strength low-alloy 921A steel in a simulated marine atmospheric environment was studied using a high-throughput experimental *** corrosion behavior,corrosion morphology,and corrosion products of 921A steels were analyzed using various techniques,including corrosion mass loss method,polarization curve,white-light interferometry,scanning electron microscopy,energy-dispersive spectrometry,microbeam X-ray fluorescence spectrometry,X-ray diffraction technique,and X-ray photoelectron *** test results indicated that 921A steel exhibits better corrosion resistance than Q450NQR1 steel in simulated harsh atmospheric environments,as evidenced by a lower corrosion mass loss rate throughout the corrosion *** corrosion products of both steels consisted ofα-FeOOH,Fe_(3)O_(4),andγ-FeOOH,withα-FeOOH being more prevalent in the rust layer of 921A steel than in Q450NQR1 *** inner rust layer of 921A steel also exhibited an appositional enrichment region of Cr,Ni,Mo,and V,leading to its superior corrosion resistance compared to that of Q450NQR1 *** efficacy of high-throughput accelerated corrosion experimental methods was highlighted for evaluating the corrosion resistance of steel materials in harsh environmental *** findings suggest that 921A steel exhibits better corrosion resistance compared to Q450NQR1 steel and has the potential to be more suitable in harsh marine atmospheric *** characterization of the rust layer structures and composition reveals the parallel enrichment of certain elements in the inner rust layer of 921A steel,which enhances its corrosion resistance.

关键词： Atmospheric corrosion High-throughput experimental method High-strength low-alloy steel Corrosion characteristics Rust layer Element enrichment

Challenges and prospects for room temperature solid-state sodiumsulfur batteries

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano research 2024年第3期17卷 1402-1426页

作者： Yashuang Qiu Jing Xu research center of Grid Energy Storage and Battery Application School of Electrical and Information EngineeringZhengzhou UniversityZhengzhou 450001China

Room temperature sodium-sulfur(Na-S)batteries,known for their high energy density and low cost,are one of the most promising next-generation energy storage ***,the polysulfide shuttling and uncontrollable Na dendrite growth as well as safety issues caused by the use of organic liquid electrolytes in Na-S cells,have severely hindered their ***-state electrolytes instead of liquid electrolytes are considered to be the most direct and effective solution to solve the above ***,its practical application is still greatly challenged due to the poor interfacial compatibility between the all-solid-state electrolytes and the anode/cathode,ionic conductivity,and the shuttle effect caused by the presence of liquid phase in the quasi-solid-state *** paper presents a comprehensive review of solid-state Na-S batteries from the perspective of regulating interfacial compatibility and improving ionic conductivity as well as suppressing polysulfide *** to different components,solid-state electrolytes were divided into five categories:solid inorganic electrolytes,solid polymer electrolytes,polymer/inorganic solid hybrid electrolytes,gel polymer electrolytes,and liquid–solid inorganic hybrid ***,the prospect of developing high performance solid-state electrolytes to improve the cycling stability of room temperature Na-S cells is envisaged.

关键词： sodium-sulfur batteries solid-state electrolytes ionic conductivity polysulfide shuttling interfacial compatibility

Electric-controlled pressure relief valve for enhanced safety in liquid-cooled lithium-ion battery packs

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第3期90卷 98-109,I0004页

作者： Yuhang Song Jidong Hou Nawei Lyu Xinyuan Luo Jingxuan Ma Shuwen Chen Peihao Wu Xin Jiang Yang Jin research center of Grid Energy Storage and Battery Application School of Electrical and Information EngineeringZhengzhou UniversityZhengzhou 450001HenanChina

The liquid-cooled battery energy sto rage system(LCBESS) has gained significant attention due to its superior thermal management ***,liquid-cooled battery pack(LCBP) usually has a high sealing level above IP65,which can trap flammable and explosive gases from battery thermal runaway and cause *** poses serious safety risks and challenges for *** this study,we tested overcharged battery inside a commercial LCBP and found that the conventionally mechanical pressure relief valve(PRV) on the LCBP had a delayed response and low-pressure relief efficiency.A realistic 20-foot model of an energy storage cabin was constructed using the Flacs finite element simulation *** studies were conducted to evaluate the pressure relief efficiency and the influence on neighboring battery packs in case of internal explosions,considering different sizes and installation positions of the ***,a newly developed electric-controlled PRV integrated with battery fault detection is introduced,capable of starting within 50 ms of the battery safety valve ***,the PRV was integrated with the battery management system and changed the battery charging and discharging strategy after the PRV was *** tests confirmed the efficacy of this method in preventing *** paper addresses the safety concerns associated with LCBPs and proposes an effective solution for explosion relief.

关键词： Pressure relief valve Liquid-cooled battery pack Explosion Flacs

维普期刊数据库

Constructing the Impossible Differential of Type-II GFN with Boolean Function and Its Application to WARP

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2024年第1期33卷 80-89页

作者： Jiali SHI Guoqiang LIU Chao LI College of Liberal Arts and Sciences National University of Defense Technology Hunan Engineering research center of Commercial Cryptography Theory and Technology Innovation State Key Laboratory of information Security Institute of Information Engineering

Type-Ⅱ generalized Feist el network(GFN) has attracted a lot of attention for its simplicity and high *** differential attack is one of the powerful cryptanalytic approaches for word-oriented block ciphers such as Feistel-like *** deduce the impossible differential of Type-Ⅱ GFN by analyzing the Boolean function in the middle *** main idea is to investigate the expression with the variable representing the plaintext(ciphertext) difference words for the internal state *** adopting the miss-in-the-middle approach,we can construct the impossible differential of Type-Ⅱ *** an illustration,we apply this approach to WARP,a lightweight 128-bit block cipher with a 128-bit key which was presented by Banik et *** SAC *** structure of WARP is a 32-branch Type-Ⅱ ***,we find two 21-round truncated impossible differentials and implement a 32-round key recovery attack on *** the 32-round key recovery attack on WARP,some observations are used to mount an effective *** the advantage of the early abort technique,the data,time,and memory complexities are 2125.69chosen plaintexts,2126.6832-round encryptions,and 2100-bit,*** the best of our knowledge,this is the best attack on WARP in the single-key scenario.

关键词： Ciphers Boolean functions Parallel processing Complexity theory

Resource Allocation for Channel Estimation in Reconfigurable Intelligent Surface-Aided Multi-Cell Networks

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Communications and information Networks 2024年第1期9卷 64-79页

作者： Yining Xu Sheng Zhou Department of Electronic Engineering Beijing National Research Center for Information Science and TechnologyTsinghua UniversityBeijing 100084China

Reconfigurable intelligent surface(RIS)is a promising solution to deal with the blockage-sensitivity of millimeter wave band and reduce the high energy consumption caused by network densification. However, deploying large scale RISs may not bring expected performance gain due to significant channel estimation overhead and non-negligible reflected *** this paper,we derive the analytical expressions of the coverage probability, area spectrum efficiency(ASE)and energy efficiency (EE)of a downlink RIS-aided multi-cell *** order to optimize the network performance, we investigate the conditions for the optimal number of training symbols of each antenna-to-antenna and antenna-to-element path (referred to as the optimal unit training overhead) in channel *** study shows that:1)RIS deployment is not“the more, the better”, only when blockage objects are dense should one deploy more RISs;2) the coverage probability is maximized when the unit training overhead is designed as large as possible;3)however,the ASE-and-EE-optimal unit training overhead exists. It is a monotonically increasing function of the frame length and a monotonically decreasing function of the average signal-to-noise-ratio (in the high signal-to-noise-ratio region). Additionally,the optimal unit training overhead is smaller when communication nodes deploy particularly few or many antennas.

关键词： reconfigurable intelligent surface multi-cell network directional transmissions channel estimation resource allocation stochastic geometry

FSCIL-EACA: Few-Shot Class-Incremental Learning Network Based on Embedding Augmentation and Classifier Adaptation for Image Classification

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2024年第1期33卷 139-152页

作者： Ruru ZHANG Haihong E Meina SONG School of Computer Science Beijing University of Posts and Telecommunications Education Department information Network Engineering research center Beijing University of Posts and Telecommunications

The ability to learn incrementally is critical to the long-term operation of AI systems. Benefiting from the power of few-shot class-incremental learning(FSCIL), deep learning models can continuously recognize new classes with only a few samples. The difficulty is that limited instances of new classes will lead to overfitting and exacerbate the catastrophic forgetting of the old classes. Most previous works alleviate the above problems by imposing strong constraints on the model structure or parameters, but ignoring embedding network transferability and classifier adaptation(CA), failing to guarantee the efficient utilization of visual features and establishing relationships between old and new classes. In this paper, we propose a simple and novel approach from two perspectives: embedding bias and classifier bias. The method learns an embedding augmented(EA) network with cross-class transfer and class-specific discriminative abilities based on self-supervised learning and modulated attention to alleviate embedding bias. Based on the adaptive incremental classifier learning scheme to realize incremental learning capability,guiding the adaptive update of prototypes and feature embeddings to alleviate classifier bias. We conduct extensive experiments on two popular natural image datasets and two medical datasets. The experiments show that our method is significantly better than the baseline and achieves state-of-the-art results.

关键词： Training Adaptation models Visualization Image recognition Prototypes Self-supervised learning Power capacitors