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Multiuser underwater acoustic communication using single-element virtual time reversal mirror

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Chinese Science Bulletin 2009年第8期54卷 1302-1310页

作者： YIN JingWei WANG YiLin WANG Lei HUI JunYing national laboratory of Underwater Acoustic Technology Harbin Engineering University Harbin 150001 China

Pattern time delay shift coding(PDS) scheme is introduced and combined with spread spectrum tech-nique called SS-PDS for short which is power-saving and competent for long-range underwater acoustic ***-element virtual time reversal mirror(VTRM) is presented in this paper and validated by the lake trial *** single-element VTRM in multiuser communication system based on SS-PDS can separate different users' information simultaneously at master node as indicated in the simulation results.

关键词：时间延迟多用户元素水声通信转镜虚拟综合布线系统 PDS系统

Magnetic field-induced non-linear transport in HfTe5

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national Science Review 2022年第10期9卷 98-104页

作者： Cheng Zhang Jinshan Yang Zhongbo Yan Xiang Yuan Yanwen Liu Minhao Zhao Alexey Suslov Jinglei Zhang Li Pi Zhong Wang Faxian Xiu State Key laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing Fudan University State Key laboratory of Surface Physics and Department of Physics Fudan University Zhangjiang Fudan International Innovation Center Fudan University State Key laboratory of High-performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences School of Physics Sun Yat-Sen University State Key laboratory of Precision Spectroscopy East China Normal University national High Magnetic Field laboratory Anhui Province Key laboratory of Condensed Matter Physics at Extreme Conditions High Magnetic Field Laboratory of the Chinese Academy of Sciences Institute for Advanced Study Tsinghua University Collaborative Innovation Center of Quantum Matter Shanghai Qi Zhi Institute 12. Shanghai Research Center for Quantum Sciences

The interplay of electron correlations and topological phases gives rise to various exotic phenomena including fractionalization,excitonic instability and axionic *** discovered transition-metal pentatellurides can reach the ultra-quantum limit in low magnetic fields and serve as good candidates for achieving such a ***,we report evidence of density wave and metal-insulator transition in HfTe5induced by intense magnetic *** the non-linear transport technique,we detect a distinct non-linear conduction behavior in the longitudinal resistivity within the a-c plane,corresponding to the formation of a density wave induced by magnetic *** high fields,the onset of non-linear conduction in the Hall resistivity indicates an impurity-pinned magnetic freeze-out as the possible origin of the insulating *** frozen electrons can be gradually reactivated into mobile states above a threshold of electric *** experimental evidence calls for further investigation into the underlying mechanism of the bulk quantum Hall effect and field-induced phase transitions in pentatellurides.

关键词： topological state quantum transport electron correlation density wave non-linear transport

Accurate fundamental invariant-neural network representation of ab initio potential energy surfaces

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national Science Review 2023年第12期10卷 26-39页

作者： Bina Fu Dong H.Zhang State Key laboratory of Molecular Reaction Dynamics and Center for Theoretical and Computational Chemistry Dalian Institute of Chemical Physics Chinese Academy of Sciences Hefei national laboratory University of Chinese Academy of Sciences

Highly accurate potential energy surfaces are critically important for chemical reaction dynamics. The large number of degrees of freedom and the intricate symmetry adaption pose a big challenge to accurately representing potential energy surfaces(PESs) for polyatomic reactions. Recently, our group has made substantial progress in this direction by developing the fundamental invariant-neural network(FI-NN)approach. Here, we review these advances, demonstrating that the FI-NN approach can represent highly accurate, global, full-dimensional PESs for reactive systems with even more than 10 atoms. These multi-channel reactions typically involve many intermediates, transition states, and products. The complexity and ruggedness of this potential energy landscape present even greater challenges for full-dimensional PES representation. These PESs exhibit a high level of complexity, molecular size, and accuracy of fit. Dynamics simulations based on these PESs have unveiled intriguing and novel reaction mechanisms, providing deep insights into the intricate dynamics involved in combustion, atmospheric, and organic chemistry.

关键词： FI-NN full-dimensional PESs multi-channel reaction reaction mechanism

Reducing Network Traffic of Token Protocol Using Sharing Relation Cache

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Tsinghua Science and Technology 2007年第6期12卷 691-699页

作者：王海霞汪东升李鹏王惊雷李崇民 Research Institute of Information Technology National Laboratory for Information Science and Technology Tsinghua University

Token protocol provides a new coherence framework for shared-memory multiprocessor systems. It avoids indirections of directory protocols for common cache-to-cache transfer misses, and achieves higher interconnect bandwidth and lower interconnect latency compared with snooping protocols. However, the broadcasting increases network traffic, limiting the scalability of token protocol. This paper describes an efficient technique to reduce the token protocol network traffic, called sharing relation cache. This cache provides destination set information for cache-to-cache miss requests by caching directory information for recent shared data. This paper introduces how to implement the technique in a token protocol. Simulations using SPLASH-2 benchmarks show that in a 16-core chip multiprocessor system, the cache reduced the network traffic by 15% on average.

关键词： token protocol sharing relation cache network traffic

Exploitation of genetic resources based on regulome and gene editing in crops

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Science China(Life Sciences) 2020年第9期63卷 1406-1409页

作者： Yunzhen Li Wenhao Yan national Key laboratory of Crop Genetic Improvement Huazhong Agricultural UniversityWuhan 430070China

Future breeding programs have to meet diverse demands of different consumers, which require massive genetic resources and variations. However, the number of natural existing haplotypes is always limited due to domestication and breeding process (Tanksley and Mc Couch, 1997). Compared with traditional genetic cloning approaches, elucidating how one gene is transcribed and how it regulates downstream workhorses will generate more information on the casual mutation(s) of the gene and its downstream targets.

关键词： breeding crops transcribed

Green synthesis of MnO_x nanostructures and studies of their supercapacitor performance

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Science China Chemistry 2015年第4期58卷 627-633页

作者： Wei Du Xiaoqian Xu Di Zhang Qingyi Lu Feng Gao State Key laboratory of Coordination Chemistry Nanjing national laboratory of Microstructures Coordination Chemistry Institute School of Chemistry and Chemical Engineering Nanjing University Department of Materials Science and Engineering Nanjing University

Manganese oxides with different crystalline phases and morphologies were prepared by calcining Mn CO3 precursors. The Mn CO3 precursors with different morphologies were obtained through a green route under hydrothermal conditions with orange pericarp extracting solution as the reducing agent. By calcining the precursor under different temperatures and atmospheres, Mn Ox with different stoichiometric ratios(i.e., Mn O, Mn O2, Mn2O3, and Mn3O4) can be obtained. Electrochemical studies reveal that among these manganese oxides, Mn O or Mn O2 are more suitable as supercapacitor working electrodes than Mn2O3 or Mn3O4. They exhibit high specific capacitance up to 296.6 F/g and also possess good cycling stability, which make them potential electrode materials for supercapacitors.

关键词： MnOx nanostructures green synthesis supercapacitor

Multi-pair massive MIMO amplify-and-forward relaying system with low-resolution ADCs:performance analysis and power control

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Science China(Information Sciences) 2018年第2期61卷 164-181页

作者： Qimei CUI Yinjun LIU Yinsheng LIU Weiliang XIE Yong ZHAO national Engineering laboratory for Mobile Network Security Beijing University of Posts and Telecommunications State Key laboratory of Rail Traffic Control and Safety Beijing Jiaotong University China Telecom Corporation Limited

In this paper, we focus on a general multi-pair massive MIMO amplify-and-forward(AF) relaying system where the relay antennas employ low-resolution analog-to-digital converters(ADCs) to reduce the hardware cost. First, considering the effect of low quantization on channel estimation, a tight closed form approximation of the system ergodic achievable rate is derived. Second, some asymptotic analysis is presented to reveal the impacts of the system parameters on the achievable rate. Particularly, the generalized power scaling schemes are characterized. The results indicate that in some cases, when the number of relay antennas grows without bound, the impact of the finite resolution ADCs on data transmission can be eliminated. To enhance the achievable rate of the quantized systems, the optimal user and relay power control schemes are proposed. Furthermore, to reap all the benefits of low-resolution ADCs, another power control scheme is also designed to minimize the total power consumption while guaranteeing the quality-of-service(Qo S)requirement of each user, which can help draw some useful insights into the optimal ADC resolution from power saving perspectives. The simulation results confirm the accuracy of our theoretical analysis and the effectiveness of the proposed power control schemes.

关键词： massive MIMO relaying system imperfect CSI low quantization power control

On the use of H-inf criterion in channel estimation and precoding in massive MIMO systems

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Science China(Information Sciences) 2017年第2期60卷 151-164页

作者： Peng XU Dongming WANG Feng QI School of Computer Science and Engineering Northeastern University national Mobile Communications Research laboratory Southeast University Key laboratory of Opto-Electronic Information Processing Institute of AutomationChinese Academy of Science

In this paper, a channel estimation(CE) and precoding scheme by using H-infinity(H-inf) criterion for mitigation of pilot contamination(PC) in massive multiple input multiple output(MIMO) orthogonal frequency division multiplexing(OFDM) systems is investigated. Firstly, different thresholds in H-inf CE and precoding are considered. Secondly, asymptotic analysis is presented to simplify the H-inf precoding, which shows that the complexity of an order of magnitude is reduced. Thirdly, approximate downlink achievable data rates per user are studied for different CE and precoding schemes, such as H-inf and minimum mean square error(MMSE) CE, MMSE, zero-forcing(ZF) and H-inf precoding. The analysis shows that the proposed scheme can provide dual mitigation to the PC. That is, the H-inf CE mitigates the PC by adjusting its thresholds, and the H-inf precoding is utilized to suppress the PC by considering inter-cell interference. The numerical results show that joint use of H-inf CE and H-inf precoding outperforms existing schemes in terms of mitigation to the PC.

关键词： massive MIMO pilot contamination precoding channel estimation H-inf

A review of measurement methods for peracetic acid (PAA)

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Frontiers of Environmental Science & Engineering 2020年第5期14卷 127-136页

作者： Chen Cheng Haodong Li Jinling Wang Hualin Wang Xuejing Yang national Engineering laboratory for Industrial Wastewater Treatment East China University of Science and Technology(ECUST)Shanghai 200237China State Key laboratory of Chemical Engineering ECUSTShanghai 200237China

Peroxyacetic acid has been widely used in food,medical,and synthetic chemical fields for the past several ***,peroxyacetic acid has gradually become an effective alternative disinfectant in wastewater disinfection and has strong redox capacity for removing micro-pollutants from drinking ***,commercial peroxyacetic acid solutions are primarily multi-component mixtures of peroxyacetic acid,acetic acid,hydrogen peroxide,and *** the process of water treatment,peroxyacetic acid and hydrogen peroxide(H2O2)often coexist,which limits further investigation on the properties ofperoxyacetic ***,analytical methods need to achieve a certain level of selectivity,particularly when peroxyacetic acid and hydrogen peroxide *** review summarizes the measurement and detection methods of peroxyacetic acid,comparing the principle,adaptability,and relative merits of these methods.

关键词： Peroxyacetic acid Measurement methods Titration Colorimetric Chromatography NMR