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Rising utilization of stable isotopes in tree rings for climate change and forest ecology

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Journal of Forestry Research 2024年第1期35卷 103-116页

作者： ru huang Chenxi Xu Jussi Grießinger Xiaoyu Feng Haifeng Zhu Achim Bräuning National Institute of Natural Hazards Beijing 100085People’s Republic of China Key Laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029People’s Republic of China CAS Center for Excellence in Life and Paleoenvironment Beijing 100044People’s Republic of China Institute of Geography Friedrich-Alexander-University of Erlangen-Nuremberg91058 ErlangenGermany State Key Laboratory of Tibetan Plateau Earth System Environment and Resources(TPESER)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101People’s Republic of China University of Chinese Academy of Sciences Beijing 100049People’s Republic of China

Analyses of stable isotopes(C,O,H)in tree rings are increasingly important cross-disciplinary *** rapid development in this field documented in an increasing number of publications requires a comprehensive *** study includes a bibliometric analysis-based review to better understand research trends in tree ring stable isotope ***,1475 publications were selected from the Web of Science Core Collection for *** findings are that:(1)numbers of annual publications and citations increased since *** 1974 to 1980,there were around two relevant publications per ***,from 2020 to 2022,this rose sharply to 109 publications per ***,average article citations were less than four per year before 1990,but were around four per article per year after 2000;(2)the major subjects using tree ring stable isotopes include forestry,geosciences,and environmental sciences,contributing to 42.5%of the total during 1974-2023;(3)the top three most productive institutions are the Chinese Academy of Sciences(423),the Swiss Federal Institute for Forest,Snow and Landscape Research(227),and the University of Arizona(204).These achievements result from strong collaborations;(4)review papers,for example,(Dawson et al.,Annu Rev Ecol Syst 33:507-559,2002)and(McCarroll and Loader,Quat Sci Rev 23:771-801,2004),are among the most cited,with more than 1000 citations;(5)tree ring stable isotope studies mainly focus on climatology and ecology,with atmospheric CO_(2) one of the most popular *** 2010,precipitation and drought have received increasing *** on this analysis,the research stages,key findings,debated issues,limitations and direc-tions for future research are *** study serves as an important attempt to understand the progress on the use of stable isotopes in tree rings,providing scientific guid-ance for young researchers in this field.

关键词： Tree rings Stable isotopes Web of Science Bibliometric

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An isolated symmetrical 2T2R cell enabling high precision and high density for RRAM-based in-memory computing

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Science China(Information Sciences) 2024年第5期67卷 287-294页

作者： Yaotian LING Zongwei WANG Yuhang YANG Lin BAO Shengyu BAO Qishen WANG Yimao CAI ru huang School of Integrated Circuits Beijing Advanced Innovation Center for Integrated Circuits Peking University State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications

In-memory computing(IMC), leveraging emerging memories, holds significant promise in overcoming memory limitations and improving energy efficiency. However, the prevailing IMC array structure based on serially connected transistors and memory cells(1T1R/2T2R), along with the signed weight mapping scheme, can lead to asymmetrical weight sensing issues(AWS) due to electrical asymmetry within the1T1R/2T2R structure, particularly in highly scaled cells where the transistor's resistance becomes significant. In this paper, we propose and fabricate an electrically symmetric memory cell based on a physically isolated 2T2R structure for IMC. This design aims to enhance the precision and density of RRAM-based IMC arrays. The 2T2R cells are manufactured using the back-end-of-line(BEOL) process of a commercial40 nm technology platform. The feasibility of this design is verified through measured and simulated results,showcasing its capability to address the issue of AWS. Compared to conventional 2T2R cells, this design achieves a considerably smaller transistor footprint without compromising accuracy, while also improving integration density by 42.2%. These innovative memory cell advancements have the potential to further advance high-energy-efficient IMC technology.

关键词： RRAM 2T2R multi-level storage weight asymmetry in-memory computing

Urolithiasis: From pathogenesis to management (part two)

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Asian Journal of Urology 2024年第2期11卷 137-138页

作者： Guohua Zeng Wei Zhu ru huang Department of Urology The First Affiliated Hospital of Guangzhou Medical UniversityGuangzhouChina

Embarking on a scholarly exploration of the intricate landscape of urolithiasis,the second part of the special section in the Asian Journal of Urology serves as a continuum to the scholarly discourse initiated in its *** is a common condition affecting 5%-10%of the global population[1].Despite significant progress in understanding the pathogenesis and management of urolithiasis,it remains a substantial public health *** objective of the special section in the Asian Journal of Urology is to provide an updated knowledge on the pathogenesis,diagnosis,and management of *** this part two of the special section,we stillfocus on the aspects of stone pathogenesis,treatment,complications prevention,and the application of new technologies.

关键词： pathogenesis prevention diagnosis

Post-layout simulation driven analog circuit sizing

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Science China(Information Sciences) 2024年第4期67卷 289-300页

作者： Xiaohan GAO Haoyi ZHANG Siyuan YE Mingjie LIU David Z.PAN Linxiao SHEN runsheng WANG Yibo LIN ru huang School of Integrated Circuits Peking University School of Computer Science Peking University Department of Electrical and Computer Engineering University of Texas at Austin Institute of Electronic Design Automation Peking University

Post-layout simulation provides accurate guidance for analog circuit design, but post-layout performance is hard to be directly optimized at early design stages. Prior work on analog circuit sizing often utilizes pre-layout simulation results as the optimization objective. In this work, we propose a post-layoutsimulation-driven(post-simulation-driven for short) analog circuit sizing framework that directly optimizes the post-layout simulation performance. The framework integrates automated layout generation into the optimization loop of transistor sizing and leverages a coupled Bayesian optimization algorithm to search for the best post-simulation performance. Experimental results demonstrate that our framework can achieve over 20% better post-layout performance in competitive time than manual design and the method that only considers pre-layout optimization.

关键词： analog EDA transistor sizing Bayesian optimization post-layout simulation

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Predictive value of intracranial high-density areas in neurological function

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World Journal of Psychiatry 2024年第7期14卷 1080-1086页

作者： Zhi-Juan Lu Jin-Xing Lai Jing-ru huang Shu-Hua Xie Zhao-Hui Lai Department of Neurology Ganzhou People’s HospitalGanzhou 341000Jiangxi ProvinceChina

BACKGROUND Intracranial high-density areas(HDAs)have attracted considerable attention for predicting clinical outcomes;however,whether HDAs predict worse neurological function and mental health remains controversial and unclear,which requires further *** this prospective study,96 patients with acute ischemic stroke(AIS)who accepted endovascular mechanical thrombectomy(EMT)were *** enrolled patients underwent cranial computed tomography(CT)examination within 24 hours after *** data in terms of National Institutes of Health Stroke Scale(NIHSS),the 3-month modified Rankin Scale(mRS),self-rating depression scale(SDS),and self-rating anxiety scale(SAS)scores were collected and compared between patients with HDAs and non-HDAs and between patients with good and poor clinical *** to patients without HDAs,patients with HDAs presented severe neurological deficits(admission NIHSS score:18±3 vs 19±4),were more likely to have post-stroke disabilities(mRS<3:35%vs 62%),and suffered more severe depression(SDS score:58±16 vs 64±13)and anxiety disorder(SAS score:52±8 vs 59±10).Compared to patients with a good prognosis,patients with a poor prognosis presented severe neurological deficits(admission NIHSS score:17±4 vs 20±3),were more likely to have HDAs on CT images(64%vs 33%),and suffered more severe depression(SDS score:55±19 vs 65±11)and anxiety(SAS score:50±8 vs 58±12).Multivariate analysis revealed that HDAs were independent nega-tive prognostic *** In conclusion,HDAs on CT images predicted poor prognosis and severe depressive and anxiety symptoms in patients with AIS who underwent EMT.

关键词： Acute ischemic stroke Endovascular mechanical thrombectomy High-density areas Depressive disorder Anxiety disorder

Tuning the ferroelectricity of Hf0.5Zr0.5O2 with alloy electrodes

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Science China(Information Sciences) 2024年第8期67卷 321-330页

作者： Keqin LIU Bingjie DANG Zhiyu YANG Teng ZHANG Zhen YANG Jinxuan BAI Zelun PAN ru huang Yuchao YANG Beijing Advanced Innovation Center for Integrated Circuits School of Integrated Circuits Peking University School of Electronic and Computer Engineering Peking University Center for Brain Inspired Chips Institute for Artificial Intelligence Peking University Center for Brain Inspired Intelligence Chinese Institute for Brain ResearchBeijing

Tuning ferroelectricity of Hf0.5Zr0.5O2is crucial for facilitating its practical applications in various fields, including in-memory and neuromorphic computing. Previous studies have revealed that the electrodes have a significant influence on ferroelectricity, and changing electrode materials can realize different but discrete ferroelectric polarization values. Here, we introduce an alloy-electrode method, in order to achieve gradual and accurate modulation of ferroelectric polarization, especially useful for matching the polarization charges at the interface of ferroelectric insulators and ferroelectric semiconductors. Au and W electrodes are chosen as baselines for realizing weak and strong ferroelectric polarization, where the intermediate states can be achieved by adjusting the ratio of metals in the Au-W alloy. To demonstrate the generality of this approach, the Cu-W alloy electrode is also realized for tuning ferroelectric polarization. The effect of alloy electrodes on device leakage current, endurance, and retention is evaluated. In addition, the temperature stability of ferroelectric capacitors is tested, where limited changes in both remnant polarization and coercive voltages are observed, showing the great potential of the ferroelectric hafnium oxide. Such gradual modulation of ferroelectric polarization could facilitate the application of Hf0.5Zr0.5O2in in-memory and neuromorphic computing.

关键词： ferroelectric hafnium oxide alloy electrode gradual modulation temperature stability

Hole mobility enhancement in monolayer WSep-type transistors through molecular doping

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Science China(Information Sciences) 2024年

作者： Shiyuan LIU Xiong XIONG Xin WANG Xinhang SHI ru huang Yanqing WU Wuhan National High Magnetic Field Center and School of Integrated Circuits Huazhong University of Science and Technology School of Integrated Circuits and Beijing Advanced Innovation Center for Integrated Circuits Peking University

Two-dimensional(2D) transition metal dichalcogenide(TMDC) semiconductor materials exhibit extraordinary electrical properties, holding promise for the realization of next-generation complementary metal-oxide-semiconductor(CMOS) devices at ultimate scaling. However, constrained by effective device doping strategies, the hole mobility and device performance of tungsten diselenide(WSe2) p-type transistors,especially monolayer chemical vapor deposition(CVD)-grown WSe2, have not met expectations. In this paper, an effective performance enhancement of monolayer WSe2p-type transistor was achieved through a molecular doping strategy. Synthesizing monolayer WSe2directly on SiO2back-gated substrates and leveraging energy band alignment design, 4-nitrobenzenediazonium tetrafluoroborate(4-NBD) molecular dopant with a concentration of 10 mM was utilized to modulate the Fermi level position of monolayer WSe2for hole doping. The devices demonstrated a more than 98% increase in hole mobility, reaching up to97 cm2·V-1·s-1while maintaining the current on/off ratio of 108. Monolayer p-type WSe2transistors with 1 μm channel length exhibit a high drive current surpassing 176 μA· μm-1, exceeding previous CVDWSe2devices with similar channel length. This straightforward and effective approach to improving the electrical performance of WSe2transistors paves the way for advanced logic technologies based on transition metal dichalcogenide semiconductors.

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Investigation and mitigation of Mott neuronal oscillation fluctuation in spiking neural network

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Science China(Information Sciences) 2024年第2期67卷 291-301页

作者： Lindong WU Zongwei WANG Lin BAO Linbo SHAN Zhizhen YU Yunfan YANG Shuangjie ZHANG Guandong BAI Cuimei WANG John ROBERTSON Yuan WANG Yimao CAI ru huang School of Integrated Circuits Peking University Beijing Advanced Innovation Center for Integrated Circuits State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications Department of Engineering University of Cambridge

Mott devices, featuring low hardware cost and high energy efficiency, have been demonstrated as a key oscillatory element in artificial neurons to enable spiking neural networks(SNNs) such as conversionbased SNNs(CSNNs). However, there will be inevitably non-ideal fluctuation in the oscillation behavior,causing the accuracy degradation of networks. In this paper, we investigate the Mott neuronal oscillation fluctuation(NOF) through experiments and modeling. The results show that the NOF phenomenon conforms to Gaussian distribution and originates from thermal fluctuation induced switching voltage variations. We construct a two-layer CSNN for image recognition tasks to study the NOF effect and propose the activation function boundary(AFB) method to strengthen the stability of the network. The results indicate that AFB can improve the accuracy of CSNN by up to 15.5% by tightening output distribution.

关键词： Mott neuron oscillation fluctuation variation-aware Mott neuronal model conversion-based spiking neural network activation function boundary

Tungsten chalcogenides as anodes for potassium-ion batteries

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Tungsten 2024年第2期6卷 278-292页

作者： Yu-Han Wu Wei-Hao Xia Yun-Zhuo Liu Peng-Fei Wang Yu-Hang Zhang Jin-ru huang Yang Xu De-Ping Li Li-Jie Ci School of Environmental and Chemical Engineering Shenyang University of TechnologyShenyang 110870China Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education) Nankai UniversityTianjin 300071China State Key Laboratory of Advanced Welding and Joining School of Materials Science and EngineeringHarbin Institute of Technology(Shenzhen)Shenzhen 518055China Department of Chemistry University College LondonLondon WC1H 0AJUnited Kingdom

Potassium-ion batteries(PIBs)by virtue of their strong cost competitiveness and similar electrochemical properties to lithiumion batteries have been deemed to be a promising electrochemical energy storage *** promote the application in the commercial market,developing electrode materials with high specifi c capacities,superior cycling stability,and reliable safety is of great *** materials as an important component of PIBs play a decisive role,among which twodimensional transition metal chalcogenides(2D TMCs)have attracted wide attention owing to their unique material and electrochemical *** the 2D TMCs’family,molybdenum chalcogenides as fl agship are the most studied materials and demonstrated the potential as *** the deepening of research on 2D TMCs,another shining member that possesses similar properties to molybdenum chalcogenides,tungsten chalcogenides(WS_(2),WSe_(2),and WTe_(2)),has aroused tremendous *** many inspiring results,various challenges remain to be further addressed;meanwhile,some results are still unclear and ***,this review fi rst introduces their material properties and electrochemical storage ***,we systematically overview the research progress and put forward promoting improvement ***,challenges and opportunities that would be future research directions are discussed.

关键词： Electrochemical energy storage Potassium-ion batteries Anodes Tungsten chalcogenides

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