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Optical and electrical nano eco-sensors using alternative deposition of charged layer

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Frontiers of Materials Science 2011年第1期5卷 40-49页

作者： Syed Rahin AHMED Seong Cheol HONG Jaebeom LEE department of Nanomedical Engineering College of Nanoscience and Nanoengineering Pusan National University Miryang 627-709 Korea

This review focuses on layer by layer （LBL） assembly-based nano ecological sensor （hereafter, eco-sensor） for pesticide detection, which is one of the most versatile methods. The effects of pesticides on human health and on the environment （air, water, soil, plants, and animals） are of great concern due to their increasing use. We highlight two of the most popular detecting methods, i.e., fluorescence and electrochemical detection of pesticides on an LBL assembly. Fluorescence materials are of great interest among researchers for their sensitivity and reliable detection, and electrochemical processes allow us to investigate synergistic interactions among film components through charge transfer mechanisms in LBL film at the molecular level. Then, we noted some prospective directions for development of different types of sensing systems.

关键词： pesticides fluorescence electrochemistry layer by layer (LBL)

Metastability of π-π stacking between the closed-shell ions of like charges

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Chinese Journal of Structural Chemistry 2024年第5期43卷 22-29页

作者： Jiayao Li Xinru Peng Shiwei Yin Changwei Wang Yirong Mo Key Laboratory for Macromolecular Science of Shaanxi Province School of Chemistry&Chemical EngineeringShaanxi Normal UniversityXi'an710119China department of nanoscience Joint School of Nanoscience&NanoengineeringUniversity of North Carolina at GreensboroGreensboroNC 27401USA

Planar cations or anions can form stacks in crystals or solutions,where the surrounding or environment plays a decisive role as demonstrated in previous ***,it remains unclear whether these counterintuitive interactions possess any inherent stability or are thoroughly repulsive if the constraint of environment is *** this work,we explored the inherent stability ofπ-πstacking between closed-shell ions of like charges with prototypes derived from experimental *** inherent metastability was identified by the characteristic local minima and the transition states preventing their dissociation and verified by ab initio molecular dynamics(AIMD)*** nature of involved interactions was deciphered with the energy decomposition approach based on the block-localized wavefunction method(BLW-ED).Like the conventional neutralπ-πstacking interactions,electron correlation is the most attractive energy *** it is overturned by the Coulombic repulsion between net charges for all modes of dimerization,resulting in the overall repulsive inter-cation or anion *** from van der Waals interactions were also observed in the reduced density gradient *** origin of the metastability was elucidated by examining the contributions of individual physical factors to the *** inherent metastability originates from the electron correlation,which dramatically increases due to the enhanced overlap between ions from a transition state to its corresponding minimum.

关键词： π-πstacking interactions Metastability Valence bond theory Energy decomposition analysis Electron correlation

Wear Resistance and Non-Magnetic Layer Formation on 316L Implant Material with Plasma Nitriding

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Journal of Bionic Engineering 2014年第4期11卷 620-629页

作者： Ali Fatih Yetim Mustafa Yazici department of Mechanical Engineering Faculty of Engineering and Architecture Erzurum Technical University Erzurum 25700 Turkey department of nanoscience and nanoengineering Ataturk University Erzurum 25240 Turkey

In this study, the applicability of plasma nitriding treatment in the production of non-magnetic and corrosion resistant layer on 316L stainless steel implant material was investigated. 316L stainless steel substrates were plasma nitrided at temperatures of 350 ℃, 375 ℃, 400 ℃, 425 ℃ and 450 ℃ for 2 h in a gas mixture of 50% N2-50% H2, respectively. It was determined that the treatment temperature is the most important factor on the properties of the corrosion resistant layer of 316L stainless steel. The results show that s-phase formed at the temperatures under 400 ℃, and at the temperatures above 400 ℃, instead of s-phase, CrN and y＇-Fe4N phases were observed in the modified layer. The electrical resistivity and surface roughness of the modified layer increase with treatment temperature. Under 400 ℃ the corrosion resistance increased with the temperature, above 400 ℃ it decreased with the increase in treatment temperature. It was analyzed that the electrical resistivity and the soft （ideal） ferro- magnetic properties of 316L stainless steel increased with treatment temperature during nitriding treatment. Also, plasma ni- triding at low temperatures provided magnetic behavior close to the ideal untreated 316L stainless steel.

关键词： 316L stainless steel biomaterials plasma nitriding magnetic properties wear electrical resistivity

Level of polycyclic aromatic hydrocarbon emission in the ambient air and residual ash from a typical municipal solid waste open burning site in Nigeria

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Waste Disposal and Sustainable Energy 2020年第2期2卷 105-111页

作者： Olusola Adedayo Adesina Adeyinka Olumide Adesina Jamiu Adetayo Adeniran department of Chemical and Petroleum Engineering Afe Babalola UniversityAdo-EkitiNigeria department of nanoscience joint school of nanoscience and nanoengineering University of North CarolinaGreensboroUSA Climate and Ocean-Atmosphere Studies Laboratory Department of Atmospheric and Oceanic SciencesPeking UniversityBeijingChina Environmental Engineering Research Laboratory Department of Chemical EngineeringUniversity of IlorinIlorinNigeria

Open burning of municipal solid waste(MSW)is a common practice in *** of compounds of polycyclic aromatic hydrocarbon(PAHs)in ambient air and ash residues from burning of these wastes pose a great danger to the *** study investigated the contribution of open burning of MSW to the levels of PAHs in ambient air and ash residues from the burning *** samples were obtained from six sampling locations at a MSW burning *** foam passive samplers were used in collecting ambient air *** of PAHs was carried out using GC-MS operated in selected ion monitoring *** trend of ambient concentration of PAHs was;ΣPAHs AS-A(4.023)>AS-B(3.798)>AS-D(3.468)>AS-C(3.288),while average concentration of PAHs in the ash was 6.12 mg/*** of PAHs in ash samples ranged from 5.69-6.34 mg/*** component analysis(PCA)showed that most of the PAHs in the ambient were from MSW *** results obtained suggest that concerted effort of the government and the relevant stakeholders is required to safeguard the environment and humans from PAH pollution from open burning of MSW.

关键词： Pahs Open burning Toxicity equivalent PUF Ash

Advances in the study of the host-guest interaction by using coronene as the guest molecule

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Chinese Chemical Letters 2019年第2期30卷 292-298页

作者： Jianqiao Li Yuxin Qian Wubiao Duan Qingdao Zeng department of Chemistry School of ScienceBeijing Jiaotong University CAS Key Laboratory of Standardization and Measurement for Nanotechnology CAS Center for Excellence in NanoscienceNational Center for Nanoscience and Technology (NCNST)

Host-guest chemistry in two-dimensional (2D) networks has gained much interest for the new functionalities and potential applications, such as separation technology, photogenic crystals and biomimetic surfaces. Nanoporous supramolecular networks are assembled by a range of non-covalent forces like hydrogen bonds, van der Waals interactions and coordinate bonds, to immobilize guest molecules of different sizes and shapes. In this review, we mainly presented the effect of coronene on the host-guest architecture. Coronene (COR) is chosen to be the promising guest molecule and it can embed, cover, or change the host networks in different host-guest systems. All of the research in the review was finished with assistance of scanning tunneling microscope (STM). These studies were called upon impose controlling on host-guest systems and revealed the behaviors of COR clusters as guest molecules.

关键词： Host-guest chemistry Coronene Molecular template 2D self-assembly Scanning tunneling microscopy(STM)

Reduction of Internal Standard Signals in Quantitative MALDI-TOF Mass Spectrometry

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Journal of Analytical Sciences, Methods and Instrumentation 2012年第3期2卷 120-125页

作者： Walter B. Wilson Dickson M. Wambua Norman H. L. Chiu department of Chemistry and Biochemistry University of North Carolina at Greensboro Greensboro USA department of Chemistry and Biochemistry University of North Carolina at Greensboro Greensboro USA 2department of nanoscience Joint School of Nanoscience and Nanoengineering Greensboro USA. department of nanoscience Joint School of Nanoscience and Nanoengineering Greensboro USA.

The advantages of combining qualitative and quantitative analysis on a single analytical technique have further extended the applications of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) to the quantitation of various biomolecules. To achieve absolute quantitation, it is necessary to perform a calibration with standard dilutions. For the purpose of measuring DNA samples, a pure DNA oligonucleotide at different concentrations was chosen as a standard to perform the calibration of MALDI-TOF MS. In order to overcome the variation of signal intensity from repeated measurements of each DNA standard dilution, fixed amount of an internal standard was added into each DNA standard dilution. Instead of maintaining at a constant level, the signals of fixed amount of internal standard were decreased 73% from its initial level while the signals of DNA standard continued to increase within a linear dynamic range for quantitation from 0.20 μM to 12.5 μM of DNA. Attempts to identify the cause of signal reduction were systematically carried out. This is the first report on the extent of signal reduction in quantitative MALDI-TOF MS. These results represent a limitation on using MALDI-TOF MS to monitor the changes in concentration of two different compounds within a chemical or biological system.

关键词： MALDI Mass Spectrometry Quantitation

A carbon-oxygen-bridged ladder-type building block for efficient donor and acceptor materials used in organic solar cells

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Science Bulletin 2017年第19期62卷 1331-1336页

作者： Zuo Xiao Fan Liu Xinjian Geng Jianqi Zhang Shizhe Wang Yujun Xie Zhen Li Huai Yang Yongbo Yuan Liming Ding Center for Excellence in nanoscience (CAS) Key Laboratory of Nanosystem and Hierarchical Fabrication (CAS)National Center for Nanoscience and Technology department of Chemistry Wuhan University College of Engineering Peking University school of Physics & Electronics Central South University

A carbon-oxygen-bridged ladder-type donor unit （CO5） was invented and prepared via an ＂intramolecu- lar demethanolization cyclization＂ approach. Its single crystal structure indicates enhanced planarity compared with the carbon-bridged analogue indacenodithiophene （IDT）. Owing to the stronger electron-donating capability of CO5 than IDT, CO5-based donor and acceptor materials show narrower bandgaps. A donor-acceptor （D-A） copolymer donor （PCO5TPD） and an A-D-A nonfullerene acceptor （COSIC） demonstrated higher performance than IDT-based counterparts, PIDTTPD and IDTIC, respec-tively. The better performance of CO5-based materials results from their stronger light-harvesting capability and higher charge-carrier mobilities.

关键词： Ladder-type unitsCyclization reactionPlanarityCharge-carrier mobilityOrganic solar cells

A Novel Synchronization Method in Terahertz Large-Scale Antenna Array System

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Chinese Journal of Electronics 2021年第5期30卷 956-968页

作者： ZHENG Chen DING Xuhui LIU Dekang BU Xiangyuan AN Sining school of Information and Electronics Beijing Institute of Technology Microwave Electronics Laboratory Department of Microtechnology and Nanoscience Chalmers University of Technology

We focus on the problems of the accurate time delay estimation, the design of training pilots,and hybrid matrix optimization within the large-scale antenna array Terahertz(THz) broadband communication system. In contrast to the existing researches based on narrow-band arrays, we hereby shed light on the time delay estimation of broadband arrays. In THz broadband communication systems, the data symbol duration is relatively short when comparing with the dimension of the antenna array. In large-scale antenna systems,signals received in each antenna are no longer different phase-shifted copies of the same symbol, but completely different symbols in which occasion traditional narrowband structure is no longer suitable. Based on the above conclusion, firstly, we put forward a system model based on large-scale antenna arrays and Time delay line(TDL)structure. Secondly, we deduce the Cramer-Rao lower bound(CRLB) of the time delay estimation, and present a time delay estimation algorithm that could reach the CRLB. Thirdly, by minimizing the CRLB, we address the design of the training pilot and optimized TDL structure under the condition of constant envelope training pilot and modulus TDL structure. Finally, we disclose the numerical simulation results. According to the simulation results, the aforementioned method is workable in reaching the CRLB,the TDL structure can significantly surpass that of the traditional model, and the optimal pilot design method outperforms the pseudo-random pilot structure.

关键词： OFDM modulation time-domain analysis time delay estimation algorithm narrow-band arrays constant envelope training pilot frequency estimation synchronisation hybrid matrix optimization different phase-shifted copies completely different symbols THz broadband communication systems large-scale antenna systems optimal pilot design method Terahertz large-scale antenna array system modulus TDL structure occasion traditional narrow-band structure channel estimation large-scale antenna array Terahertz broadband communication system optimized TDL structure data symbol duration CRLB large-scale antenna arrays array signal processing pseudorandom pilot structure broadband arrays system model accurate time delay estimation antenna arrays Time delay line structure delay estimation

Recent advances in nanomaterials for high-performance Li–S batteries

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Journal of Energy Chemistry 2020年第8期29卷 86-106,I0004页

作者： James E.Knoop Seongki Ahn joint school of nanoscience and nanoengineering North Carolina Agricultural and Technical State UniversityGreensboroNC 27401USA Research Organization for Nano and Life Innovation Waseda University513WasedatsurumakichoShinjuku-kuTokyo 162-0041Japan

This article reviews nanotechnology as a practical solution for improving lithium-sulfur batteries. Lithiumsulfur batteries have been widely examined because sulfur has many advantageous properties such as a high crustal abundance, low environmental impact, low cost, high gravimetric(2600 W h kg-1) and volumetric(2800 W h L-1) energy densities, assuming complete conversion of sulfur to lithium sulfide(Li2S)upon lithiation. However, lithium-sulfur batteries have not yet reach commercialization due to demerits involving the formation of soluble lithium polysulfides(Li2Sn, n=3–8), low electrical conductivity, and low loading density of sulfur. These issues arise mainly due to the polysulfide shuttle phenomenon and the inherent insulating nature of sulfur. To overcome these issues, strategies have been pursued using nanotechnology applied to porous carbon nanocomposites, hollow one-dimensional carbon nanomaterials, graphene nanocomposites, and three-dimensional carbon nanostructured matrices. This paper aims to review various solutions pertaining to the role of nanotechnology in synthesizing nanoscale and nanostructured materials for advanced and high-performance lithium–sulfur batteries. Furthermore, we highlight perspective research directions for commercialization of lithium–sulfur batteries as a major power source for electric vehicles and large-scale electric energy storage.

关键词： Nanotechnology Lithium–sulfur batteries Carbon nanomaterials Nanocomposite sulfur 3D nanostructured materials