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Ultrafast flash memory with large self-rectifying ratio based on atomically thin MoS_(2)-channel transistor

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Materials Futures 2022年第2期1卷 153-162页

作者： liwei liu Yibo Sun Xiaohe Huang Chunsen liu Zhaowu Tang Senfeng Zeng David Wei Zhang Shaozhi Deng Peng Zhou Frontier Institute of Chip and System Fudan UniversityShanghai 200433People’s Republic of China State Key Laboratory of ASIC and System School of MicroelectronicsFudan UniversityShanghai 200433People’s Republic of China State Key Laboratory of Optoelectronic Materials and Technologies Guangdong Province Key Laboratory of Display Material and TechnologySchool of Electronics and Information TechnologySun Yat-sen UniversityGuangzhou 510275People’s Republic of China

Flash memory with high operation speed and stable retention performance is in great demand to meet the requirements of big *** addition,the realisation of ultrafast flash memory with novel functions offers a means of combining heterogeneous components into a homogeneous device without considering impedance *** report proposes a 20 ns programme flash memory with 10^(8) self-rectifying ratios based on a 0.65 nm-thick MoS_(2)-channel transistor.A high-quality van der Waals heterojunction with a sharp interface is formed between the Cr/Au metal floating layer and h-BN tunnelling *** addition,the large rectification ratio and low ideality factor(n=1.13)facilitate the application of the MoS_(2)-channel flash memory as a bit-line select ***,owing to the ultralow MoS_(2)/h-BN heterojunction capacitance(50 fF),the memory device exhibits superior performance as a high-frequency(up to 1 MHz)sine signal *** results pave the way toward the potential utilisation of multifunctional memory devices in ultrafast two-dimensional NAND-flash applications.

关键词： ultra-fast flash memory metal floating gate atomic sharp interface atomic thin channel self-rectification transistor high-frequency rectifier

Effect of active species in crude oil on the interfacial tension behavior of alkali/synthetic surfactants/crude oil systems

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Petroleum Science 2008年第4期5卷 353-358页

作者： liu liwei Hou Jirui Yue Xiang＇an Zhao Ji Key Laboratory of Petroleum Engineering Ministry of Education China University of Petroleum Beijing 102249 China China Petrochemical Corporation Beijing 100029 China

The effect of active species present in crude oil on the interfacial tension （IFT） behavior of alkali/synthetic surfactants/crude oil systems was studied. The system consisted of heavy alkyl benzene sulfonate, sodium chloride, sodium hydrate and Daqing crude oil. Experimental results indicated that active species would diffuse from oil/aqueous interface to aqueous phase and finally an equilibrium could be reached in the system with increasing contact time. Moreover, the minimum IFT and equilibrium IFT values increased with increasing contact time and a linear relationship existed between dynamic IFT and f^-1/2 when IFT value approaching the minimum and after the minimum IFT was reached. This indicated that the dynamic IFT-time behavior was diffusion controlled. The oil and aqueous phases were analyzed by infrared （IR） spectroscopy. IR spectra of oil and aqueous phases illustrated that the content of active species in the oil phase decreased, but the content of active species in the aqueous phase increased after alkali reacted with crude oil. This indicated that the active species present in oil played an important role in reducing IFT.

关键词： Contact time diffusion alkali interfacial tension

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Some Identities Involving the High-Order Cauchy Polynomials

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Journal of Applied Mathematics and Physics 2022年第4期10卷 1126-1145页

作者： liwei liu Wuyungaowa Department of Mathematics College of Sciences and Technology Inner Mongolia University Hohhot China

In this paper, we consider the Cauchy numbers and polynomials of order k and give some relation between Cauchy polynomials of order k and special polynomials by using generating functions and the Riordan matrix methods. In addition, we establish some new equalities and relations involving high-order Cauchy numbers and polynomials, high-order Daehee numbers and polynomials, the generalized Bell polynomials, the Bernoulli numbers and polynomials, high-order Changhee polynomials, high-order Changhee-Genocchi polynomials, the combinatorial numbers, Lah numbers and Stirling numbers, etc.

关键词： High-Order Daehee Numbers and Polynomials The Bernoulli Numbers and Polynomials High-Order Changhee Polynomials Stirling Numbers The Lah Numbers

Interseismic and coseismic displacements of the Lushan Ms 7.0 earthquake inferred from leveling measurements

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Chinese Science Bulletin 2014年第36期59卷 5129-5135页

作者： Ming Hao Qingliang Wang liwei liu Qi Shi Second Monitoring Center China Earthquake Administration Geodetic Data Processing Center National Administration of SurveyingMapping and Geoinformation

By using precise leveling data observed between 1985 and 2010 across the south section of the Longmenshan fault zone,and eliminating the coseismic displacements caused by the Wenchuan Ms 8.0 earthquake,the interseismic vertical deformation field was *** result shows that the Lushan region,located between the Shuangshi–Dachuan fault(front range of the Longmenshan fault) and the Xinkaidian fault(south section of the Dayi fault),is situated in the intersection zone of positive and negative vertical deformation gradient zones,indicating that this zone was locked within 25 years before the Lushan *** on leveling data across the rupture zone surveyed between 2010 and 2013,and by eliminating the vertical deformation within 3 years before the earthquake,the coseismic vertical displacement was *** coseismic vertical displacement for the benchmark DD35,which is closest to the epicenter,is up to198.4 mm(with respect to MY165A).The coseismic displacement field revealed that the northwest region(hanging wall) moved upwards in comparison with the southeastern region(foot wall),suggesting that the seismogenic fault mainly underwent thrust *** comparing the coseismic and interseismic vertical deformation fields,it was found that the mechanisms of this earthquake are consistent with the elastic rebound theory; the elastic strain energy(displacement deficit) accumulated before the Lushan earthquake was released during this quake.

关键词：同震位移测量数据地震前庐山龙门山断裂带弹性应变能垂直变形发震断层

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Investigating molecular orbitals with submolecular precision on pristine sites and single atomic vacancies of monolayer h-BN

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Nano Research 2020年第8期13卷 2233-2238页

作者： liwei liu Thomas Dienel Gino Günzburger Teng Zhang Zeping Huang Cong Wang Roland Widmer Wei Ji Yeliang Wang Oliver Gröning School of Information and Electronics MIIT Key Laboratory for Low-Dimensional Quantum Structure and DevicesBeijing Institute of TechnologyBeijing100081China Empa Swiss Federal Laboratories for Materials Science and TechnologyDuebendorfCH-8600Switzerland Department of Materials Science and Engineering Cornell University and NSF-MIP Platform for the Accelerated RealizationAnalysisand Discovery of Interface Materials(PARADIM)IthacaNY14853USA Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials&Micro-nano Devices Renmin University of ChinaBeijing100872China

Understanding the influence of adsorption sites to the electronic properties of adsorbed molecules on two-dimensional(2D)ultrathin insulator is of essential importance for future organic-inorganic hybrid ***,the adsorption and electronic states of manganese phthalocyanine(MnPc)on a single layer of hexagonal boron nitride(h-BN)have been comprehensively studied by low-temperature scanning tunneling microscopy/spectroscopy and tight binding *** frontier orbitals of the MnPc can change drastically by reversible manipulation of individual MnPc molecules onto and away from the single atomic vacancies at the h-BN ***,the change of the molecular electronic configuration can be controlled depending on whether the atomic vacancy is below the metal center or the ligand of the *** findings give new insight into defect-engineering of the organic-inorganic hybrid nanodevices down to submolecular level.

关键词： hexagonal boron nitride phthalocyanine single atomic vacancy molecular orbital scanning tunneling microscopy

Effects of linker amino acids on the potency and selectivity of dimeric antimicrobial peptides

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Chinese Chemical Letters 2018年第7期29卷 1163-1166页

作者： Ming Kai Wei Zhang Huan Xie liwei liu Sujie Huang Xiao Li Zhengzheng Zhang Yuyang liu Bangzhi Zhang Jingjing Song Rui Wang School of Life Sciences Lanzhou University Lanzhou 730000 China Laboratory of Preclinical Study for New Drugs of Cansu Province School of Basic Medical Sciences Lanzhou University Lanzhou 730000 China

Dimerization is an effective strategy for designing antimicrobial peptides that combine the advantages of different native peptides. In this study, we explored the effects of different linker amino acids, including leucine, proline and aminocaproic acid, on the anticancer, antimicrobial and hemolytic activities of the heteromeric antimicrobial peptides AM-1, AM-2, and AM-3. Proline and aminocaproic acid are ideal linkers for increasing the potency and selectivity of heteromeric antimicrobial peptides. The results of MD simulations provided a rationalization for this observation. Both AM-2, which had a proline linker,and AM-3, which had an aminocaproic acid linker, adopted a compact conformation in water and a bent conformation in membranes. This change in the flexible structures of AM-2 and AM-3 could have resulted in decreased binding of these peptides to zwitterionic lipid bilayers and increased damage to mixed lipid bilayers containing acidic phospholipids. In short, these findings obtained via assessing the effects of linker amino acids will contribute to the design of ideal heteromeric antimicrobial peptides with high selectivity and potency.

关键词： Linker amino acid Flexibility Heteromeric antimicrobial peptides Potency and selectivity

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Raman spectra evidence for the covalent-like quasi-bonding between exfoliated MoS2 and Au films

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Science China(Information Sciences) 2021年第4期64卷 157-165页

作者： Xinyu HUANG Lei ZHANG liwei liu Yang QIN Qiang FU Qiong WU Rong YANG Jun-Peng LV Zhenhua NI Lei liu Wei JI Yeliang WANG Xingjiang ZHOU Yuan HUANG Institute of Physics Chinese Academy of Sciences Department of Materials Science and Engineering College of Engineering Peking University College of Materials Science and Engineering Key Laboratory of Advanced Functional MaterialsMinistry of Education of China Beijing University of Technology School of Information and Electronics MIIT Key Laboratory for Low-Dimensional Quantum Structure and DevicesBeijing Institute of Technology Songshan Lake Materials Laboratory School of Science Beijing University of Posts and Telecommunications School of Physics Southeast University Department of Physics and Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices Renmin University of China

Gold-enhanced mechanical exfoliation method attracts broad interests in recent years, which has been widely used for preparing large-area and high-quality 2D single crystals. Even many calculations predict that there is strong interaction between Au film and the exfoliated 2D crystals, direct experimental evidence is still lacking. Here, we perform Raman spectroscopy measurements for few layer MoSwith and without Au film underneath. The main peaks of MoSon Au film show no obvious change at higher frequency,however, the breathing and shear modes at low-frequency are suppressed, especially for breathing *** contrast, both breathing modes and shear modes can be detected on suspended MoSand the samples are transferred from Au film to SiO/Si. These comparison results provide direct evidence for the existence of covalent-like quasi-bonding at the interface of Au film and the exfoliated MoScrystal. This MoS/Au interface interaction presents a special pinning-effect for low-frequency rigid vibration. Similar pinning-effect is also discovered in WS/Au system. Our work reports the suppression of low-frequency Raman modes of MoS, WSon Au film, which will deliver new inspiration for studying other interactions between layered materials and solid surfaces.

关键词： MoS$_{2}$ Raman spectroscopy gold-enhanced mechanical exfoliation low-frequency raman modes covalent-like quasi-bonding

Toxicity assessment and long-term three-photon fluorescence imaging of bright aggregation-induced emission nanodots in zebrafish

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Nano Research 2016年第7期9卷 1921-1933页

作者： Dongyu Li Xinyuan Zhao Wei Qin Hequn Zhang Yue Fei liwei liu Ken-Tye Yong Guangdi Chen Ben Zhong Tang Jun Qian State Key Laboratory of Modern Optical Instrumentation Centre for Optical and Electromagnetic Research Zhejiang Provincial Key Laboratory for Sensing Technologies Zhejiang University Hangzhou 310058 China Bioelectromagnetics Laboratory Institute of Environmental Health Zhejiang University School of Medicine Hangzhou 310058 China Department of Chemistry The Hang Kong University of Science & Technology Clear Water Bay Kowloon Hong Kong China Changchun University of Science and Technology (CUST) Changchun 130022 China School of Electrical and Electronic Engineering Nanyang Technological University Singapore 639798 Singapore

Aggregation-induced emission （AIE） luminogen displays bright fluorescence and has photobleaching resistance in its aggregation state. It is an ideal fluorescent contrast agent for bioimaging. Multiphoton microscopy is an important tool for bioimaging since it possesses the ability to penetrate deep into biological tissues. Herein, we used AIE luminogen together with multiphoton microscopy for long-term imaging of zebrafish. A typical AIE luminogen, 2,3-bis（4-（phenyl（4- （1,Z2-triphenylvinyl） phenyl）amino）phenyl） fumaronitrile （TPE-TPA-FN or TTF）, was encapsulated with 1,2-distearoyl-sn-glycero-3-phosphoethanola-mine-N- [methoxy（polyethylene glycol）-2000] （DSPE-mPEG2000） to form nanodots that exhibited bright three-photon fluorescence under 1,560 nm-femtosecond （fs） laser excitation. The TTF-nanodots were chemically stable in a wide range of pH values and showed no in vivo toxicity in zebrafish according to a series of biological tests. The TTF-nanodots were microinjected into zebrafish embryos, and the different growth stages of the labeled embryos were monitored with a three-photon fluorescence microscope. TTF-nanodots could be traced inside the zebrafish body for as long as 120 hours. In addition, the TTF-nanodots were utilized to target the blood vessel of zebrafish, and three-photon fluorescence angiogram was performed. More importantly, these nanodots were highly resistant to photobleaching under 1,560 nm-fs excitation, allowing long-term imaging of zebrafish.

关键词： biocompatible organicnanodots aggregation-inducedemission three-photon fluorescence bioimaging zebrafish

Halogen-doped phosphorescent carbon dots for grayscale patterning

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Light(Science & Applications) 2022年第7期11卷 1464-1474页

作者： Yanfeng liu Mahmoud Al-salihi Yong Guo Roman Ziniuk Songtao Cai Luwei Wang Yuan Li Zhigang Yang Dengfeng Peng Kai Xi Zhongfu An Xudong Jia liwei liu Wei Yan Junle Qu Center for Biomedical Photonics and College of Physics and Optoelectronic Engineering Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong ProvinceShenzhen UniversityShenzhen 518060China School of Chemistry and Chemical Engineering Nanjing University163 Xianlin RoadNanjing 210023China Key Laboratory of Flexible Electronics(KLOFE)and Institute of Advanced Materials(IAM) Nanjing Tech University(NanjingTech)30 South Puzhu RoadNanjing 211816China

Flexible organic materials that exhibit dynamic ultralong room temperature phosphorescence(DURTP)via photoactivation have attracted increasing research interest for their fascinating functions of reversibly writing-reading-erasing graphic information in the form of a long ***,due to the existence of a nonnegligible activation threshold for the initial exposure dose,the display mode of these materials has thus far been limited to binary *** resorting to halogen element doping of carbon dots(CDs)to enhance intersystem crossing and reduce the activation threshold,we were able to produce,for the first time,a transparent,flexible,and fully programmable DURTP composite film with a reliable grayscale display *** of promising applications in UV photography and highly confidential steganography were constructed,partially demonstrating the broad future applications of this material as a programmable platform with a high optical information density.

关键词： activation resort negligible