检索结果-南通市图书馆

Dynamic Inertia Response Support by Energy Storage System with Renewable Energy Integration Substation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2020年第2期8卷 260-266页

作者： Yeuntae yoo Seungmin jung Gilsoo Jang Korea University SeoulKorea Hanbat National University DaejeonKorea

In recent years,the expansion of renewable energy in electric power systems has been increasing at such a rapid pace that it has started affecting frequency *** generators connected to the grid produce variable amounts of power,and in most cases have no inherent inertia response(IR)to the system ***,the high penetration of renewable generators in the system results in low inertia and frequency *** renewable generators account for a high proportion of the supply in a power system,the use of energy storage systems(ESSs)with frequency-support algorithms(in the place of synchronous generators)can stabilize the *** participation of ESSs in frequency support must be organized precisely,so that they are fully devoted to their own *** this paper,the frequency-support parameters of ESSs are calculated for achieving stable frequency response from a *** estimation and calibration process is conducted during the active power-order change of the ESSs in the substation,and is verified through electromagnetic-transients-including-DC(EMTDC)-based simulations.

关键词： Energy storage system(ESS) frequency response inertia renewable energy substation

High performance of TiO_(2)/Cu_(x)O photoelectrodes for regenerative solar energy storage in a vanadium photoelectrochemical cell

在线全文

学校读者我要写书评

暂无评论

Green Energy & Environment 2022年第4期7卷 704-711页

作者： Harin yoo Doohwan Lee jung Hyeun Kim Department of Chemical Engineering University of Seoul163 SiripdaeroDongdaemun-guSeoul02504South Korea

Photocatalysts for harvesting solar energy to either electricity or chemical fuels have attracted much attention recently, but they have big obstacles such as wide bandgaps and rapid charge recombinations to overcome for final applications. In this study, we investigates a useful method to utilize vanadium redox pairs, which are commonly applied for vanadium redox flow batteries, to diminish charge recombinations and thus to enhance photocurrent response in regenerative solar energy storage. The results reveal significant improvements in photocurrent density by forming cuprous and cupric oxides in TiO_(2)/Cu_(x)O electrodes under solar AM 1.5 illuminations using the vanadium photoelectrochemical storage cell at 0.025 mol L^(-1) of vanadium redox species in the acid electrolytes. In addition, the stabilized photocurrent density of the copper content optimized TiO_(2)/Cu_(x)O electrodes is almost tripled from the TiO_(2) only electrode because the charge recombinations can be mitigated with the content optimized TiO_(2)/Cu_(x)O electrodes. Therefore, the optimized TiO_(2)/Cu_(x)O electrode results in the highest charge storing performance in the catholyte chamber, and the roles of vanadium redox species are also clearly demonstrated.

关键词： Photocatalyst Photoelectrochemical Copper oxide Charge recombination Redox pairs

“Nanospace engineering”by the growth of nano metal-organic framework on dendritic fibrous nanosilica(DFNS)and DFNS/gold hybrids

在线全文

学校读者我要写书评

暂无评论

Nano Research 2020年第3期13卷 775-784页

作者： Ngoc Minh Tran Soeun jung Hyojong yoo Department of Materials Science and Chemical Engineering Hanyang UniversityAnsanGyeonggi-do15588Republic of Korea

Advanced hybrid nanomaterials(nanohybrids)with unique tailored morphologies and compositions have been used for the target-oriented catalysts due to the structural or supportive properties of each moiety and the synergistic properties of the individual *** rational design and development of nanohybrids by integrating highly porous silica into a nano metal-organic framework(NMOF)are expected to enable unique nanospace engineering in the resulting systems to optimize their utility in the target ***,we report the design and fabrication of advanced nanohybrids composed of dendritic fibrous nanosilica(DFNS)and DFNS/gold(DFNS/Au)hybrids as the core and zinc-based NMOF(Zn-NMOF)as the shell(DFNS@Zn-NMOF)through a solution-based *** combined fibrous morphology of DFNS and micropores of NMOF can be directly employed for nanospace engineering in the resulting multi-compositional and hierarchical systems in a controllable *** DFNS/Au dots@Zn-NMOF nanohybrid shows improved catalytic performance in the Knoevenagel condensation reaction,attributed mainly to the cooperative effect stemming from the suitably organized configurations of each component.

关键词： nanohybrids nanospace engineering dendritic fibrous nanosilica nano metal-organic framework cooperative catalytic performance

Metadynamics sampling in atomic environment space for collecting training data for machine learning potentials

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

npj Computational Materials 2021年第1期7卷 1171-1179页

作者： Dongsun yoo Jisu jung Wonseok Jeong Seungwu Han Department of Materials Science and Engineering and Research Institute of Advanced Materials Seoul National UniversitySeoulKorea Samsung Display Co. Ltd.1Samsung-roGiheung-guYongin-siGyeonggi-doKorea

The universal mathematical form of machine-learning potentials(MLPs)shifts the core of development of interatomic potentials to collecting proper training ***,the training set should encompass diverse local atomic environments but conventional approaches are prone to sampling similar configurations repeatedly,mainly due to the Boltzmann *** such,practitioners handpick a large pool of distinct configurations manually,stretching the development period *** overcome this hurdle,methods are being proposed that automatically generate training ***,we suggest a sampling method optimized for gathering diverse yet relevant configurations *** is achieved by applying the metadynamics with the descriptor for the local atomic environment as a collective *** a result,the simulation is automatically steered toward unvisited local environment space such that each atom experiences diverse chemical environments without *** apply the proposed metadynamics sampling to H:Pt(111),GeTe,and Si *** these examples,a small number of metadynamics trajectories can provide reference structures necessary for training high-fidelity *** proposing a semiautomatic sampling method tuned for MLPs,the present work paves the way to wider applications of MLPs to many challenging applications.

关键词： dynamics collective stretching

Stick-and-play system based on interfacial adhesion control enhanced by micro/nanostructures

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2021年第9期14卷 3143-3158页

作者： jung II yoo Seung Hyun Kim Heung Cho Ko School of Materials Science and Engineering Gwangju Institute of Science and Technology(GIST)Gwangju 61005Republic of Korea

The evolution of membrane-type electronics has facilitated the development of stick-and-play systems,which confer diverse electrical functions to various planar or arbitrary curvilinear *** stick-and-play concept is based on the development of thin electronic devices in a printable format and their subsequent transfer to target *** development of this technology requires control of the interfacial adhesion of the electronic prints for retrieval from a carrier and transfer to the target ***,we discuss the transfer printing for membrane-type electronics,starting from an overview of materials available for flexible substrates,transfer printing of electronic prints for retrieval,and assembly for further ***,we explain the stick-and-play concept based on fabricated membrane-type electronics;"stick" and “play"refer to the transfer of electronic devices and the performance of their electronic functions,*** particular,we broadly survey various methods based on micro/nanostructures,including gecko-inspired,interlocking,cephalopod-sucker-inspired,and cilia structures,which can be employed to stick-and-play systems for enhancing interfacial adhesion with complex target surfaces under dynamic and wet ***,we highlight the stick-and-play system application of micro/nanostructures for skin-attachable biomedical electronics,e-textiles,and environmental monitoring electronics.

关键词： transfer printing interfacial adhesion flexible electronics stick-and-play system bioinspired adhesive

Direct synthesis of highly conductive poly（3,4- ethylenedioxythiophene）：poly（4-styrenesulfonate）（PEDOT：PSS）/graphene composites and their applications in energy harvesting systems

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2014年第5期7卷 717-730页

作者： Dohyuk yoo Jeonghun Kim jung Hyun Kim Department of Chemical and Biomolecular Engineering Yonsei University 50 Yonsei-ro Seodaemun-gu Seou1120-749 Republic of Korea Electronic Materials Division R&D Center Dongjin Semichem Co. Ltd. 625-3 Yodang-Ri Yanggam-Myeon Hwaseong-Gun Gyeonggi-Do Republic of Korea

We report for the first time highly conductive poly（3,4-ethylenedioxythiophene）： poly（4-styrenesulfonate）（PEDOT：PSS）/graphene composites fabricated by in situ polymerization and their applications in a thermoelectric device and a platinum （Pt）-free dye-sensitized solar cell （DSSC） as energy harvesting systems. Graphene was dispersed in a solution of poly（4-styrenesulfonate）（PSS） and polymerization was directly carried out by addition of 3,4-ethylenedioxythiophene （EDOT） monomer to the dispersion. The content of the graphene was varied and optimized to give the highest electrical conductivity. The composite solution was ready to use without any reduction process because reduced graphene oxide was used. The fabricated film had a conductivity of 637 ***-1, corresponding to an enhancement of 41%, after the introduction of 3 wt.% graphene without any further complicated reduction processes of graphene being required. The highly conductive composite films were employed in an organic thermoelectric device, and the device showed a power factor of 45.7 μW·m^-1K^-2 which is 93% higher than a device based on pristine PEDOT：PSS. In addition, the highly conductive composite films were used in Pt-free DSSCs, showing an energy conversion efficiency of 5.4%, which is 21% higher than that of a DSSC based on PEDOT：PSS.

关键词： direct synthesis conductive polymer graphene composite thermoelectric material dye-sensitized solar cell

Oxidative coupling of methane over LaAlO3 perovskite catalysts prepared by a co-precipitation method: Effect of co-precipitation pH value

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2019年第8期28卷 1-8,I0001页

作者： Yujin Sim Jihoon yoo Jeong-Myeong Ha Ji Chul jung Department of Chemical Engineering Myongji UniversityYongin 17058 Republic of Korea Clean Energy Research Center Korea Institute of Science and TechnologySeoul 02792 Republic of Korea

Oxidative coupling of methane(OCM) was conducted over LaAlO3X catalysts that were prepared by a coprecipitation method using different co-precipitation pH values(X = 6–10). The aim is to investigate the effect of p H values on the catalytic activity of La AlO3 catalysts in this reaction. The results showed that the co-precipitation pH value affected greatly on the formation of chemical species of precipitate precursors in the co-precipitation step, leading to different phases of the finally obtained LaAlO3 *** the co-precipitation pH value increased up to 8, the lanthanum-related phases such as La2 O3 and La(OH)3 were gradually formed as by-products, preventing the formation of LaAlO3 perovskite crystalline structure and facilitating the formation of oxygen vacancies on catalyst surface. However, at pH value of9 or higher, the lanthanum content in the precipitate precursor was increased greatly. Not LaAlO3 perovskite but lanthanum-related phases were developed as main phases, reducing their catalytic activities in this reaction. Among LaAlO3 catalysts, the one prepared at pH = 8 showed the highest C2 yield due to its well-developed oxygen vacancies and electrophilic lattice oxygen. Therefore, the co-precipitation pH value strongly affected the LaAlO3 catalyst activity in OCM reaction. A precious pH control should be required to prepare various perovskite catalysts for the OCM.

关键词： LaAlO3 Perovskite Oxidative coupling of methane Co-precipitation pH value

Slip-enhanced Reverse Electrodialytic Power Generation in Ion-selective Nanochannels

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2013年第1期22卷 36-41页

作者： Byeongdong Kang Jaisuk yoo Hyun jung Kim Dong-Kwon Kim Department of Mechanical Engineering Ajou University

Power generation by reverse electrodialysis in ion-selective nanochannels is numerically investigated. Especially,in the present study, the influence of hydrodynamic slip at the surface of nanochannels is investigated. The current-potential characteristics of the nanochannels are calculated by solving several governing equations:Nernst-Planck equation for the ionic concentrations, the Poisson equation for the electric potential, and the Navier-Stokes equation for the diffusioosmotic flow. Hydrodynamic slip is applied as the boundary condition at the surface of nanochannels. As the slip length increases, the diffusioosmotic flow velocity and electrical conductance of ions increase because the friction at the surface of nanochannels decreases. It is shown that the power generation is enhanced by 44% with a moderate 100nm slip length by using a nanochannel with 10nm height.

关键词： Reverse electrodialysis Ion-selective nanochannel Power generation Slip length

Self‑Powered Airflow Sensor Based on Energy Harvesting of Ventilation Air in Buildings

在线全文

学校读者我要写书评

暂无评论

Advanced Fiber Materials 2023年第5期5卷 1788-1798页

作者： Moon Hyun Chung Seunghwan yoo Woo‑Nam jung Hakgeun Jeong Kyung‑Hwa yoo Department of Physics Yonsei University50 Yonsei‑RoSeodaemun‑GuSeoul 03722Republic of Korea Energy ICT Convergence Research Department Energy Efficiency Research DivisionKorea Institute of Energy Research152 Gajeong‑RoYuseong‑GuDaejeon 34129Republic of Korea Advanced Combustion Power Lab Energy Efficiency Research DivisionKorea Institute of Energy Research152Gajeong‑RoYuseong‑GuDaejeon 34129Republic of Korea Department of Mechanical Engineering Korea Advanced Institute of Science and Technology(KAIST)291 Daehak‑RoYuseongDaejeon 34141Republic of Korea

Heating,ventilation,and air conditioning(HVAC)systems account for one-third of the total energy consumption in office *** use of airflow measurements to control the operation of HVAC systems can reduce energy consumption;thus,a sensor capable of monitoring airflow in a duct system is *** nanogenerators(TENGs)can be utilized as self-powered sensors in airflow-driven TENGs(ATENGs)as self-powered *** employing ferroelectric materials and surface modifications,the surface charges of TENGs can be *** this study,fibrous-mat TENGs were prepared using ferroelectric materials consisting of poly(vinylidene fluoride-co-trifluoroethylene)(PVDF-TrFE)and polyamide 11(nylon-11).And these materials were subsequently ***(3,4-ethylenedioxythiophene):poly(styrenesulfonate)was added to PVDF-TrFE to enhance the ferroelectric crystalline phase.X-ray diffraction analysis revealed that this incorporation affects theβ*** addition,the surface of nylon-11 was modified using the electrospray technique for post-treatment,thereby improving the interfacial adhesion between the *** materials were then utilized in fibrous-mat ATENGs(FM-ATENGs)to demonstrate their practical *** FM-ATENGs can be effectively used in an Arduino airflowcheck sensor,showcasing their potential for application in HVAC systems,to enhance airflow control and energy efficiency.

关键词： HVAC Airflow-driven triboelectric nanogenerator Building energy harvesting Fibrous mat Airflow sensor