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PALES: Optimizing Secure Data Deletion in SSDs via Page Group and Reprogram Speedup

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Chinese Journal of Electronics 2022年第1期31卷 40-51页

作者： NIE Shiqiang WU Weiguo zhang Chi ZHANG Chen Department of Computer Science and Technology Xi’an Jiaotong University

As solid-state drives(SSD) have been widely adopted, secure data deletion becomes an essential component for ensuring user privacy, preventing sensitive data leakage. Due to the erase-before-write property,erasure operation and scrub operation substituting for overwriting technologies are proposed to meet the requirements. However, both methods bring the severe page-copying issue, declining read/write performance, and shortening the lifetime of SSD. In this paper, this issue is alleviated by reserving pages at the page allocation stage to mitigate program disturbance and increasing program step voltage during reprogramming operation to reduce the reprogram latency. The proposed scheme is evaluated by a series of experiments; the results show that the proposed scheme could achieve significant deletion time reduction and alleviate page-copying overhead.

关键词： NAND flash Data deletion Reprogram Program voltage

Extreme Risk Measurement of Carbon Market Considering Multifractal Characteristics

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Journal of Systems Science & Complexity 2023年第6期36卷 2497-2514页

作者： ZHU Dandan ZHANG Chen PAN Di School of Management Hefei University of TechnologyHefei230009China School of Economics and Management Shanghai University of Political Science and LawShanghai201701China Key Laboratory of Process Optimization and Intelligent Decision-Making Hefei University of TechnologyHefei230009China

Influenced by the global economy,politics,energy and other factors,the price of carbon market fluctuates sharply.It is of great practical significance to explore a suitable measurement method of extreme risk of carbon market.Considering that the return series of carbon market has the characteristics of leptokurtosis,fat tail,skewness and multifractal,and there maybe many extreme risk values in the carbon market,this paper introduces the Skewed-t distribution which can describe the characteristics of leptokurtosis,fat tail and skewness of return series into MSM model which can describe multifractal characteristic of return series to model volatility of carbon market.On the basis,based on the extreme value theory,this paper constructs Skewed-t-MSM-EVT model to measure extreme risk of carbon market.This paper chooses EUA market as the object to study extreme risk of carbon market,and draws the following conclusions:Skewed-t-MSM-EVT model has significantly higher prediction accuracy for carbon market's Va R than MSM-EVT models under other distributions(including normal distribution,t distribution,GED distribution);Skewed-t-MSM-EVT model is superior to traditional Skewed-t-FIGARCH-EVT and Skewed-t-GARCH-EVT models in predicting carbon market's Va R.This research has important practical significance for accurately grasping the risk of carbon market and promoting energy conservation and emission reduction.

关键词： Carbon market extreme value theory multifractal Skewed-t distribution VaR

Experimental investigation for ultra-precision cutting of nickel based superalloy with the assistance of magnetic field

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Science China(Technological Sciences) 2022年第9期65卷 2170-2177页

作者： XIAO JunFeng GUO Feng ZHANG Chen chen Xiao zhang JianGuo XU JianFeng State Key Laboratory of Digital Manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China School of Mechanical Engineering Hubei University of TechnologyWuhan 430068China

Nickel based superalloy is an important material because of its excellent properties under high temperatures.However,it is a difficult-to-machine material due to its low thermal conductivity,which can cause undesired localized high temperatures in the processing area.In this study,magnetic field-assisted end face turning experiments of nickel-based superalloy is carried out under the assistance of external magnetic fields of different strengths formed by permanent magnets.The experiment results show that,compared with ordinary machining,the chip morphology is improved,the oscillation of cutting force F_(c),F_(a),and Ffare significantly reduced by 90%,88%,and 78%,and the surface roughness Ra is improved from 23 to 13 nm,the P-V value of the fan-shaped area of the machined surface is reduced,and hardness and ductility are improved after the magnetic field is applied.The experiment results indicate that the application of a magnetic field is an efficient and convenient approach to improve the cutting performance of nickel based superalloy.

关键词： magnetic field assisted cutting nickel based superalloy ultra-precision cutting

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微囊泡与糖尿病视网膜病变相关性研究现状

中华眼底病杂志 2017年第3期33卷 321-324页

作者：张惟陈松天津市眼科医院天津市眼科学与视觉科学重点实验室天津市眼科研究所天津医科大学眼科临床学院 300020

微囊泡（MV）是机体各种细胞在正常或病理状态下从细胞膜表面直接出芽脱落形成的小囊泡样物质，可通过多种途径激活凝血、炎症反应并影响血管内皮细胞功能。MV可介导内皮细胞损伤、血栓形成、促进新生血管形成等病理过程在糖尿病视网膜... 详细信息

微囊泡（MV）是机体各种细胞在正常或病理状态下从细胞膜表面直接出芽脱落形成的小囊泡样物质，可通过多种途径激活凝血、炎症反应并影响血管内皮细胞功能。MV可介导内皮细胞损伤、血栓形成、促进新生血管形成等病理过程在糖尿病视网膜病变（DR）发病机制中发挥重要作用；血浆MV水平可能成为监测DR发生发展的有效指标。进一步深入研究MV形成机制、组成成分及其在DR血管病变中的作用，探讨MV作为反映DR进展与程度的新的生物标志物和药物治疗靶点的可能性，将为DR血管病变诊断治疗开辟新的前景。

关键词：糖尿病视网膜病变纠芮因学脂质体炎症内皮,血管综述

Fast Fading Channel Estimation for OFDM Systems with Complexity Reduction

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Chinese Journal of Electronics 2021年第6期30卷 1173-1177页

作者： ZHANG Chen LI Dan College of Electronic Science and Technology National University of Defense Technology

Channel estimation plays a significant role in the Inter-carrier interference(ISI) mitigation and symbol detection in Orthogonal frequency division multiplexing(OFDM) systems. As the speed of mobile terminal increases, the channel changes rapidly, causing fast fading which will degrade the system performance. In this paper, a low complexity fast fading channel estimation method suited for scattered pilot OFDM systems is proposed. This method is characterized by estimating channel matrix directly in the frequency domain, which can significantly reduce the channel estimation complexity with good system performance. Simulation results verify its superiority over the existing estimation methods.

关键词： OFDM Fast fading channel Basis expansion model

Multifunctional photon conversion materials for enhancing silicon solar cells

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Light(Science & Applications) 2024年第4期13卷 598-601页

作者： Yiyan zhang Guanying chen MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage School of Chemistry and Chemical EngineeringHarbin Institute of Technology150001 HarbinChina

A type of multifunctional erbium(Er^(3+))and ytterbium(Yb^(3+))codoped NaY(WO4)2 phosphors,with simultaneous photon upconversion,photon quantum cutting,and luminescence ratiometric temperature sensing abilities,have b... 详细信息

关键词： photon luminescence quantum

Roles of organelle-specific autophagy in hepatocytes in the development and treatment of non-alcoholic fatty liver disease

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Chinese Medical Journal 2022年第14期135卷 1673-1681页

作者： Yizhi zhang Yu chen Fourth Department of Liver Disease(Difficult and Complicated Liver Diseases and Artificial Liver Center) Beijing You’an Hospital Affiliated to Capital Medical UniversityBeijing 100069China Beijing Municipal Key Laboratory of Liver Failure and Artificial Liver Treatment Research Beijing 100069China

Non-alcoholic fatty liver disease(NAFLD)is a disorder of lipid metabolism.The lipotoxic intermediates of lipid metabolism cause mitochondrial dysfunction and endoplasmic reticulum stress.Organelle-specific autophagy is responsible for the removal of dysfunctional organelles to maintain intracellular homeostasis.Lipophagy contributes to lipid turnover by degrading lipid droplets.The level of autophagy changes during the course of NAFLD,and the activation of hepatocyte autophagy might represent a method of treating NAFLD.

关键词： Autophagy Lipophagy Mitophagy Reticulophagy Non-alcoholic fatty liver disease

Advances in Mn‑Based Electrode Materials for Aqueous Sodium‑Ion Batteries

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纳微快报:英文版 2023年第11期15卷 19-60页

作者： Changsheng Ding ZHANG Chen Chuanxiang Cao Yu Liu Yanfeng Gao School of Materials Science and Engineering Shanghai UniversityShanghai 200444People’s Republic of China Shanghai Institute of Ceramics Chinese Academy of SciencesShanghai 200050People’s Republic of China Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources Qinghai Institute of Salt LakesChinese Academy of SciencesXining 81000People’s Republic of China

Aqueous sodium-ion batteries have attracted extensive attention for large-scale energy storage applications,due to abundant sodium resources,low cost,intrinsic safety of aqueous electrolytes and eco-friendliness.The electrochemical performance of aqueous sodium-ion batteries is affected by the properties of electrode materials and electrolytes.Among various electrode materials,Mn-based electrode materials have attracted tremendous attention because of the abundance of Mn,low cost,nontoxicity,eco-friendliness and interesting electrochemical performance.Aqueous electrolytes having narrow electrochemical window also affect the electrochemical performance of Mn-based electrode materials.In this review,we introduce systematically Mn-based electrode materials for aqueous sodium-ion batteries from cathode and anode materials and offer a comprehensive overview about their recent development.These Mn-based materials include oxides,Prussian blue analogues and polyanion compounds.We summarize and discuss the composition,crystal structure,morphology and electrochemical properties of Mn-based electrode materials.The improvement methods based on electrolyte optimization,element doping or substitution,optimization of morphology and carbon modification are highlighted.The perspectives of Mn-based electrode materials for future studies are also provided.We believe this review is important and helpful to explore and apply Mn-based electrode materials in aqueous sodium-ion batteries.

关键词： Sodium-ion batteries Aqueous electrolytes Mn-based electrode materials Electrochemical performance Improvement methods

Silicon-processes-compatible contact engineering for twodimensional materials integrated circuits

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Nano Research 2023年第11期16卷 12471-12490页

作者： Li Gao zhangyi chen Chao chen Xiankun zhang Zheng zhang Yue zhang Academy for Advanced Interdisciplinary Science and Technology Beijing Advanced Innovation Center for Materials Genome EngineeringUniversity of Science and Technology BeijingBeijing 100083China School of Materials Science and Engineering Peking UniversityBeijing 100871China Key Laboratory of Advanced Materials and Devices for Post-Moore Chips Ministry of EducationUniversity of Science and Technology BeijingBeijing 100083China

Two-dimensional(2D)semiconductors,especially transition metal dichalcogenides(TMDCs),have been proven to be excellent channel materials for the next-generation integrated circuit(IC).However,the contact problem between 2D TMDCs and metal electrodes has always been one of the main factors restricting their development.In this review,we summarized recent work on 2D TMDCs contact from the perspective of compatible integration with silicon processes and practical application requirements,including the contact performance evaluation indicators,special challenges encountered in 2D TMDCs,and recent optimization methods.Specifically,we sorted out and highlighted the performance indicators of 2D TMDCs contacts,including contact resistance(RC),contact scaling,contact stability,and contact electrical/thermal conductivity.Special challenges of 2D TMDCs and metal contact,such as severe Fermi level pinning,large RC,and difficult doping,are systematically discussed.Furthermore,typical methods for optimizing 2D TMDCs RC,edge contact strategies for scaling contact lengths,and solutions for improving contact stability are reviewed.Based on the current research and problems,the development direction of 2D TMDCs contacts that meet the silicon-based compatible process and application performance requirements is proposed.

关键词： two-dimensional(2D)semiconductors transition metal dichalcogenides field effect transistors contact engineering