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Forest Ecosystems 2024年第1期11卷 32-41页

作者： Chen Wang Shuguang liu Yu Zhu Andrew R.Smith Ying Ning deming Deng National engineering Laboratory for Applied Technology of Forestry&Ecology in South China Central South University of Forestry and TechnologyChangsha 410004China Technology Innovation Center for Ecological Conservation and Restoration in Dongting Lake Basin Ministry of Natural ResourcesChangsha 410007China College of Life Science and Technology Central South University of Forestry and TechnologyChangsha 410004China School of Ecology and Environment Hainan UniversityHaikou 570228China School of Natural Sciences Bangor UniversityGwyneddLL572UWUK College of Forestry Central South University of Forestry and TechnologyChangsha 410004China Hunan Prospecting Designing&Research General Institute for Agriculture Forestry&IndustryChangsha 410007China

Understanding the spatial variation,temporal changes,and their underlying driving forces of carbon sequestration in various forests is of great importance for understanding the carbon cycle and carbon management *** carbon density and sequestration in various Cunninghamia lanceolata forests,extensively cultivated for timber production in subtropical China,vary with biodiversity,forest structure,environment,and cultural factors remain poorly explored,presenting a critical knowledge gap for realizing carbon sequestration supply potential through *** on a large-scale database of 449 permanent forest inventory plots,we quantified the spatial-temporal heterogeneity of aboveground carbon densities and carbon accumulation rates in Cunninghamia lanceolate forests in Hunan Province,China,and attributed the contributions of stand structure,environmental,and management factors to the heterogeneity using quantile age-sequence analysis,partial least squares path modeling(PLS-PM),and hot-spot *** results showed lower values of carbon density and sequestration on average,in comparison with other forests in the same climate zone(i.e.,subtropics),with pronounced spatial and temporal ***,quantile regression analysis using carbon accumulation rates along an age sequence showed large differences in carbon sequestration rates among underperformed and outperformed forests(0.50 and 1.80 Mg·ha^(-1)·yr^(-1)).PLS-PM demonstrated that maximum DBH and stand density were the main crucial drivers of aboveground carbon density from young to mature ***,species diversity and geotopographic factors were the significant factors causing the large discrepancy in aboveground carbon density change between low-and high-carbon-bearing *** analysis revealed the importance of culture attributes in shaping the geospatial patterns of carbon *** work highlighted that retaining largesized DBH trees and increasing shade-t

关键词： Carbon density Carbon accumulation rate Forest age Spatial variation Cultural influence

Design of Low-Power Turbo Encoder and Decoder for NB-IoT

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Chinese Journal of electronics 2024年第2期33卷 403-414页

作者： Chong ZHANG Yuhang LIN deming WANG Jianguo HU School of Microelectronics Science and Technology Sun Yat-sen University School of Physics and Telecommunication engineering South China Normal University School of electronics and Information engineering South China Normal University Development Research Institute of Guangzhou Smart City Shenzhen Research Institute of Sun Yat-sen University

Turbo code is an error correction coding scheme close to the Shannon limit, usually used in wireless data transmission. Based on the parallel Turbo code algorithm, a parallel Turbo code circuit design scheme is *** the encoder, the recursive systematic convolutional encoder is multiplexed. The decoder is divided into branch metric, recursive, maximum likelihood ratio, and external information calculation modules. The decoding algorithm is based on Max-Log-MAP, controlling the component decoder in parallel. And the state metric calculation in the decoding circuit is combined to reduce the overall power consumption effectively, enabling the encoder and decoder to be used in narrowband Internet of things(NB-IoT). Finally, the hardware scheme of the main functional modules of Turbo code encoding and decoding is designed and implemented. The results show that the dynamic power consumption is less than 50 m W. The overall on-chip power consumption is reduced by 40% at the frequency of 125 MHz compared with previous jobs.

关键词： Measurement Wireless communication Power demand Systematics Turbo codes System-on-chip Power dissipation

Miniaturized and highly sensitive fiber-optic Fabry–Perot sensor for mHz infrasound detection

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Photonics Research 2024年第5期12卷 969-978页

作者： PEIJIE WANG YUFENG PAN JIANGSHAN ZHANG JIE ZHAI deming liu PING LU Wuhan National Laboratory for optoelectronics(WNLO)and National engineering Research Center of Next Generation Internet Access System School of Optical and Electronic InformationHuazhong University of Science and TechnologyWuhan 430074China Optics Valley Laboratory Wuhan 430074China department of electronics and Information engineering Huazhong University of Science and TechnologyWuhan 430074China

Infrasound detection is important in natural disasters monitoring,military defense,underwater acoustic detection,and other ***-optic Fabry–Perot(FP)acoustic sensors have the advantages of small structure size,long-distance detection,immunity to electromagnetic interference,and so *** size of an FP sensor depends on the transducer diaphragm size and the back cavity ***,a small transducer diaphragm size means a low ***,a small back cavity volume will increase the low cut-off frequency of the ***,it is difficult for fiber-optic FP infrasound sensors to simultaneously achieve miniaturization,high sensitivity,and extremely low detectable *** this work,we proposed and demonstrated a miniaturized and highly sensitive fiber-optic FP sensor for m Hz infrasound detection by exploiting a Cr-Ag-Au composite acoustic-optic transducer diaphragm and a MEMS technique-based spiral micro-flow *** use of the spiral micro-flow hole as the connecting hole greatly reduced the volume of the sensor and decreased the low-frequency limit,while the back cavity volume was not *** with the Cr-Ag-Au composite diaphragm,a detection sensitivity of-123.19 dB re 1 rad∕μPa at 5 Hz and a minimum detectable pressure(MDP)of1.2 mPa∕Hz^(1∕2)at 5 Hz were *** low detectable frequency can reach 0.01 Hz and the flat response range was 0.01–2500 Hz with a sensitivity fluctuation of±1.5 d ***,the size of the designed sensor was only 12 mm×Φ12.7 *** excellent characteristics make the sensor have great practical application prospects.

关键词： sound fiber cavity

Experimental Study on Semiconductor Optical Amplifiers with Angled Facets

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Chinese Journal of Lasers 1999年第1期8卷 8-11页

作者： DUAN Zigang HUANG Dexiu liu deming ZHANG Zemin (department of opto electronics engineering, Huazhong University of Science and Technology, Wuhan 430074, China) 华中理工大学光电工程系湖北武汉 430074 华中理工大学光电工程系湖北武汉

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１ＩｎｔｒｏｄｕｃｔｉｏｎＳＯＡｗｉｌｂｅｏｎｅｏｆｔｈｅｋｅｙｃｏｍｐｏｎｅｎｔｓｉｎｔｈｅａｌｏｐｔｉｃａｌｎｅｔｗｏｒｋｉｎｔｈｅｆｕｔｕｒｅ．ＳＯＡｈａｓｍａｎｙｖｅｒｙｉｍｐｏｒｔａｎｔａｐｐｌｉｃａｔｉｏｎｓ，ｓｕｃｈａｓｗａｖｅｌｅｎ...

关键词： tilted cavity antireflective coating gain semiconductor optical amplifier

DETECTION OF TRANSIENT SIGNAL USING THE DISCRETE WAVELET TRANSFORM

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国防科技大学学报 1995年第3期17卷 114-118,125页

作者： liu Zheng(department of Information electronics,Faculty of engineering,Nagoya University, Nagoya, 464,Japan)

ＤＥＴＥＣＴＩＯＮＯＦＴＲＡＮＳＩＥＮＴＳＩＧＮＡＬＵＳＩＮＧＴＨＥＤＩＳＣＲＥＴＥＷＡＶＥＬＥＴＴＲＡＮＳＦＯＲＭＬｉｕＺｈｅｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＩｎｆｏｒｍａｔｉｏｎＥｌｅｃｔｒｏｎｉｃｓ，Ｆａｃｕｌｔ... 详细信息

ＤＥＴＥＣＴＩＯＮＯＦＴＲＡＮＳＩＥＮＴＳＩＧＮＡＬＵＳＩＮＧＴＨＥＤＩＳＣＲＥＴＥＷＡＶＥＬＥＴＴＲＡＮＳＦＯＲＭＬｉｕＺｈｅｎｇ（ＤｅｐａｒｔｍｅｎｔｏｆＩｎｆｏｒｍａｔｉｏｎＥｌｅｃｔｒｏｎｉｃｓ，ＦａｃｕｌｔｙｏｆＥｎｇｉｎｅｅｒｉｎｇ，Ｎａ...

关键词：信号检测瞬态信号 DWT

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宽角度位相调控反射镜的设计与研制

红外与激光工程 2024年第4期53卷 215-222页

作者：李大琪刘保剑余德明段微波刘定权中国科学院上海技术物理研究所光学薄膜与材料研究室上海200083 上海市光学薄膜与光谱调控重点实验室上海200083 复旦大学信息科学与工程学院光科学与工程系上海200433 重庆理工大学机械工程学院重庆400054

宽角度位相调控反射镜是下一代中高轨量子通信系统中的核心元件,用于宽角度范围内信号光的高效传递与偏振态的精确调控。基于等效多层膜理论,采用介质反射膜堆加非规整位相调控膜的膜系结构,设计了一种宽角度位相调控反射镜。选择Nb2O5... 详细信息

宽角度位相调控反射镜是下一代中高轨量子通信系统中的核心元件,用于宽角度范围内信号光的高效传递与偏振态的精确调控。基于等效多层膜理论,采用介质反射膜堆加非规整位相调控膜的膜系结构,设计了一种宽角度位相调控反射镜。选择Nb2O5和SiO2分别作为高、低折射率薄膜材料,通过误差分析,优化沉积工艺,采用电子束蒸发结合离子辅助沉积的方式,在德国莱宝Lab900-plus设备上制备出该薄膜元件。研制结果表明,反射镜在780 nm处、45°±7.5°入射范围内,其反射率大于99.3%,位相差控制在3°以内,满足量子通信系统的反射率及位相差控制要求,且通过相关环境模拟实验,满足可靠性要求,为该类偏振调控薄膜元件在下一代中高轨量子卫星中的工程应用打下了坚实的基础。

关键词：光学薄膜位相调控反射镜偏振宽角度

Recent advances in halide perovskite memristors:From materials to applications

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Frontiers of physics 2024年第2期19卷 73-104页

作者： Sixian liu Jianmin Zeng Qilai Chen Gang liu department of Micro/Nano electronics School of Electronic Information and Electrical EngineeringShanghai Jiao Tong UniversityShanghai 200240China Aerospace Science&Industry Shenzhen(Group)Co.Ltd. Shenzhen 518000China

With the emergence of the Internet of Things(IoT)and the rapid growth of big data generated by edge devices,there has been a growing need for electronic devices that are capable of processing and transmitting data at low power and high *** Complementary Metal-Oxide-Semiconductor(CMOS)devices are nonvolatile and often limited by their ability for certain IoT applications due to their unnecessary power consumption for data movement in von Neuman architecture-based *** has led to a surge in research and development efforts aimed at creating innovative electronic components and systems that can overcome these shortcomings and meet the evolving needs of the information era,which share features such as improved energy efficiency,higher processing speeds,and increased *** are a novel type of electronic device that has the potential to break down the barrier between storage and *** storing data and processing information within the same device,memristors can minimize the need for data movement,which allows for faster processing speeds and reduced energy *** further improve the energy efficiency and reliability of memristors,there has been a growing trend toward diversifying the selection of dielectric materials used in *** perovskites(HPs)have unique electrical and optical properties,including ion migration,charge trapping effect caused by intrinsic defects,excellent optical absorption efficiency,and high charge mobility,which makes them highly promising in applications of *** this paper,we provide a comprehensive overview of the recent development in resistive switching behaviors of HPs and the underlying ***,we summarize the diverse range of HPs,their respective performance metrics,as well as their applications in various ***,we critically evaluate the current bottlenecks and possible opportunities in the future research of HP memristors.

关键词： halide perovskite memristor mechanism neuromorphic computing non-volatile memory

Effects of sleep deprivation on gamma oscillation of waking human EEG

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Progress in Natural Science:Materials International 2008年第12期18卷 1533-1537页

作者： Ning Li~a Yan Wang~a Mingshi Wang~a Haiying liu~(a,b) a College of Precision Instrument and opto-electronics engineering,Tianjin University,Tianjin 300072,China b department of Radiology University of Minnesota,Minneapolis,MN 55455,USA College of Precision Instrument and opto-electronics engineering Tianjin University Tianjin 300072 China department of Radiology University of Minnesota Minneapolis MN 55455 USA

This study compares and evaluates the effect of sleep deprivation (SD) on human brain cognition by analyzing the recorded EEG data under normal and 24 h sleep deprived *** auditory event-related potentials were collected from 14 healthy volunteers,and the statistical values of wavelet-transformed EEG in gamma band were decomposed by parallel factor analysis (PARAFAC) to identify where the differences appeared in the time,frequency and spatial *** results showed that the changes of brain states caused by SD appeared around 40 Hz at about 400 ms after stimulation on prefrontal and frontal *** effects of SD on neuronal activity and oscillation were *** analysis of the EEG data by the wavelet transform and PARAFAC can be an integrated way to estimate the change of brain states in the three domains.

关键词： Gamma oscillation Sleep deprivation Event-related potential Wavelet transform Parallel factor Neuronal activity

LLM4CP:Adapting Large Language Models for Channel Prediction

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Journal of Communications and Information Networks 2024年第2期9卷 113-125页

作者： Boxun liu Xuanyu liu Shijian Gao Xiang Cheng liuqing Yang State Key Laboratory of Advanced Optical Communication Systems and Networks School of ElectronicsPeking UniversityBeijing 100871China Internet of Things Thrust The Hong Kong University of Science and Technology(Guangzhou)Guangzhou 511400China Internet of Things Thrust and Intelligent Transportation Thrust The Hong Kong University of Science and Technology(Guangzhou)Guangzhou 511400China department of Electronic and Computer engineering and department of Civil and Environmental engineering The Hong Kong University of Science and TechnologyHong KongChina

Channel prediction is an effective approach for reducing the feedback or estimation overhead in massive multi-input multi-output (m-MIMO) systems. However, existing channel prediction methods lack precision due to model mismatch errors or network generalization issues. Large language models (LLMs) have demonstrated powerful modeling and generalization abilities, and have been successfully applied to cross-modal tasks, including the time series analysis. Leveraging the expressive power of LLMs, we propose a pre-trained LLM-empowered channel prediction(LLM4CP)method to predict the future downlink channel state information (CSI) sequence based on the historical uplink CSI sequence. We fine-tune the network while freezing most of the parameters of the pre-trained LLM for better cross-modality knowledge transfer. To bridge the gap between the channel data and the feature space of the LLM,preprocessor, embedding, and output modules are specifically tailored by taking into account unique channel characteristics. Simulations validate that the proposed method achieves state-of-the-art (SOTA) prediction performance on full-sample, few-shot, and generalization tests with low training and inference costs.

关键词： channel prediction massive multi-input multi-output(m-MIMO) large language models(LLMs) fine-tuning time-series