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Frequency control of future power systems: reviewing and evaluating challenges and new control methods

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Journal of Modern Power Systems and Clean Energy 2019年第1期7卷 9-25页

作者： Zeyad Assi OBAID Liana M.CIPCIGAN Lahieb ABRAHIM Mazin T.MUHSSIN College of Engineering University of Diyala Institute of Energy School of Engineering Cardiff University School of Engineering South Wales University College of Engineering Mustansiriyah University

Integration of more renewable energy resources introduces a challenge in frequency control of future power systems.This paper reviews and evaluates the possible challenges and the new control methods of frequency in future power systems.Different types of loads and distributed energy resources(DERs) are reviewed.A model representation of a population of the water heater devices for the demand side frequency response is considered.A model representation of a population of battery energy storage system(BESS)-based DERs such as smart electric vehicles(EVs) charging, large-scale BESSs, and residential and non-residential BESSs, are highlighted.The simplified Great Britain power system and the 14-machine South-East Australian power system were used to demonstrate the effectiveness of the new methods in controlling power system frequency following a disturbance.These new methods are effective in recovering the fallen frequency response and present a great potential in controlling the frequency in future power systems.

关键词： Battery energy storage system(BESS) Distributed energy resource(DER) Electric vehicle Home-based BESS large-scale BESS aggregation Demand side response Frequency control Markov chain

A highly efficient Fe-doped Ni_(3)S_(2) electrocatalyst for overall water splitting

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Nano Research 2021年第12期14卷 4740-4747页

作者： Min Wang Li Zhang Jialiang Pan Meirong Huang Hongwei Zhu State Key Lab of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing100084China Key Laboratory of Photochemical Conversion and Optoelectronic Materials Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing100190China

The development of efficient and stable electrocatalysts with earth-abundant elements for both oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)in the same electrolyte is incontrovertibly vital in water electrolysis.However,their large-scale fabrication remains a great challenge.Here,we report a self-supported electrocatalyst in the form of Fe-doped Ni_(3)S_(2) nanoparticles in-situ grown on three-dimensional(3D)conductive Fe−Ni alloy foam(Fe−Ni_(3)S_(2)/AF)by surface-assisted chemical vapor transport(SACVT)method.Homogeneous growth environment and scalability of SACVT method allow Fe−Ni3S2 nanoparticles uniformly growing on AF in large-scale.Fe−Ni_(3)S_(2)/AF exhibits high activity and durability when act as HER catalyst and OER precatalyst in alkaline media.The HER and OER overpotential at 10 mA/cm^(2) is considerably small,only 75 and 267 mV,respectively.Moreover,the electrolyzer assembled by Fe−Ni_(3)S_(2)/AF for overall water splitting exhibits a low cell voltage and high durability in long-term test.Based on experiments and theoretical calculation,the significantly enhanced activity could be originated from the incorporation of Fe,which contributed to increase the electrochemical active surface area,enhance electrical conductivity,optimize the hydrogen and H2O adsorption energy of Ni_(3)S_(2)(101)surface in HER,and form active bimetallic Ni−Fe(oxy)hydroxide in OER.The excellent durability of self-supported Fe−Ni_(3)S_(2)/AF could be benefited from the in-situ growth of Fe−Ni_(3)S_(2) nanoparticles on 3D AF,which could ensure closely mechanical adhesion between active materials and substrate,promote charge transport and increase surface area.This work provides a facile method for large-scale synthesis of electrocatalysts with high activity and long-term durability for efficient water electrolysis in alkaline media.

关键词： sulfide surface-assisted chemical vapor transport large-scale in-situ growth overall water splitting

A non-wetting and conductive polyethylene dioxothiophene hole transport layer for scalable and flexible perovskite solar cells

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Science China Chemistry 2021年第5期64卷 834-843页

作者： Chenxiang Gong Lin Zhang Xiangchuan Meng Zhi Xing Li Rao Hongyu Wang Zengqi Huang Licheng Tan Ting Hu Xiaotian Hu Yiwang Chen College of Chemistry Nanchang UniversityNanchang 330031China Institute of Polymers and Energy Chemistry Nanchang UniversityNanchang 330031China Hunan Key Laboratory for Super Microstructure and Ultrafast Process School of Physics and ElectronicsCentral South UniversityChangsha 410083China School of Materials Science and Engineering Nanchang UniversityNanchang 330031China Institute of Advanced Scientific Research(iASR) Jiangxi Normal UniversityNanchang 330022China

The regulated crystallization of perovskite and highly repeatable preparation are decisive challenges for large-scale flexible perovskite solar cells(PSCs).Herein,we synthesize an oil-soluble poly(3,4-ethylenedioxythiophene)(Oil-PEDOT)as a hole transport layer(HTL).The non-wetting Oil-PEDOT HTL can promote the quality of large-area flexible perovskite films because of its optimized crystallinity and printability.The Oil-PEDOT layer also delivers desirable conductivity and charge transport without a complex doping.Consequently,the flexible PSCs with Oil-PEDOT HTL achieve an efficiency of 19.51%and 16.70%based on 1.05 and 22.50 cm^(2),respectively.Moreover,these large-scale flexible PSCs demonstrate remarkable mechanical robustness,and the efficiency exhibits 93%retention after 7,000 bending cycles.These results show that the Oil-PEDOT is a potentially efficient HTL for fabricating efficient large-scale flexible PSCs.

关键词： non-wetting dopant-free hole transport layer flexible solar cells large-scale

Preparing a re-sequencing DNA library of 2 cancer candidate genes using the ligation-by-amplification protocol by two PCR reactions

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Science China(Life Sciences) 2009年第5期52卷 483-491页

作者： SU YeYang1,2,3, LIN Lin1,2,3, TIAN Geng1,2,3, CHEN Chen2,3, LIU Tao2,3, XU Xingya3, QI XinPeng1,2,3, ZHANG XiuQing2,3& YANG HuanMing2,3 1 Graduate School of Chinese Academy of Sciences, Beijing 100049, China 2 Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100029, China 3 Beijing Genomics Institute, Beijing 101300, China Graduate School of Chinese Academy of Sciences Beijing China Beijing Institute of Genomics Chinese Academy of Sciences Beijing China Beijing Genomics Institute Beijing China

To meet the needs of large-scale genomic/genetic studies, the next-generation massively parallelized sequencing technologies provide high throughput, low cost and low labor-intensive sequencing service, with subsequent bioinformatic software and laboratory methods developed to expand their applications in various types of research. PCR-based genomic/genetic studies, which have significant usage in association studies like cancer research, haven't benefited much from those next-generation sequencing technologies, because the shortgun re-sequencing strategy used by such sequencing machines as the Illumina/Solexa Genome Analyzer may not be applied to direct re-sequencing of short-length target regions like those in PCR-based genomic/genetic studies. Although several methods have been proposed to solve this problem, including microarray-based genomic selections and selector-based technologies, they require advanced equipment and procedures which limit their applications in many laboratories. By contrast, we overcame such potential drawbacks by utilizing a ligation by amplification (LBA) protocol, a method using a pair of Universal Adapters to randomly ligate target regions in a two-step-PCR procedure, whose Long LBA products were easily fragmented and sequenced on the next-generation sequencing machine. In this concept-proven study, we chose the consensus coding sequences of two human cancer genes: BRCA1 and BRCA2 as target regions, specifically designed LBA primer pairs to amplify and randomly ligate them. 70 target sequences were successfully amplified and ligated into Long LBA products, which were then fragmented to construct DNA libraries for sequencing on both a conventional Sanger sequencer ABI 3730xl DNA Analyzer and the next-generation 'synthesis by sequencing technology' Illumina/Solexa Genome Analyzer. Bioinformatic analysis demonstrated the utility and efficiency (including the coverage and depth of each target sequence and the SNPs detection effectiveness) of using the LBA protocol in facilitating PCR-bas

关键词： health genomics the next-generation sequencing techonology sequencing technology large-scale genomics PCR

Numerical simulation of flow separation over a backward-facing step with high Reynolds number

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Water Science and Engineering 2019年第2期12卷 145-154页

作者： Fang-fang Wang Shi-qiang Wu Sen-lin Zhu State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Nanjing Hydraulic Research Institute

large eddy simulation (LES) explicitly calculates the large-scale vortex field and parameterizes the small-scale vortices.In this study,LES and κ-ε models were developed for a specific geometrical configuration of backward-facing step (BFS).The simulation results were validated with particle image velocimetry (PIV) measurements and direct numerical simulation (DNS).This LES simulation was carried out with a Reynolds number of 9000 in a pressurized water tunnel with an expansion ratio of 2.00.The results indicate that the LES model can reveal largescale vortex motion although with a larger grid-cell size.However,the LES model tends to overestimate the top wall separation and the Reynolds stress components for the BFS flow simulation without a sufficiently fine grid.Overall,LES is a potential tool for simulating separated flow controlled by large-scale vortices.

关键词： large eddy simulation κ-ε model Backward-facing step Direct numerical simulation large-scale vortices Particle image velocimetry

Changes of tropical cyclone tracks in the western North Pacific over19792016

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Advances in Climate Change Research 2018年第3期9卷 170-176页

作者： ZHANG Wen-Qian WU Li-Guang ZOU Xu-Kai Pacific Typhoon Research Center Nanjing University of Information Science & Technology Nanjing 210044 China Key Laboratory for Climate Studies National Climate Center China Meteorological Administration Beijing 100081 China

The tropical cyclone （TC） trajectory model has been widely used to investigate the mechanism of the climate change of TC tracks. In thisstudy, the Gaussian weight interpolation method is used to calculate the beta drift in the TC track or trajectory model. By simulating historicalTC tracks, the new calculation can better simulate the spatial distribution of the frequency of TC occurrence. The improved track model isfurther used to understand the TC track change during the period of 1979e2016. In 1979e2016, the TC activity has been suppressed in theSouth China Sea （SCS） while the TC influence along the southeast coastal regions of China has been increased. The sensitivity experimentsindicate that the change of the formation location plays a dominant role in decreasing TC influence in the SCS while the change of theenvironmental steering flows increases the TC influence in the eastern coastal region of China. This study suggests that the ongoing climatechange can affect the TC activity along the coast of China.

关键词： Tropical cyclone Trajectory model Beta drift Formation position large-scale steering flows

Robust decentralized control design for aircraft engines: A fractional type

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Chinese Journal of Aeronautics 2019年第2期32卷 347-360页

作者： Muxuan PAN Liangjin CAO Wenxiang ZHOU Jinquan HUANG Ye-Hwa CHEN College of Energy and Power Engineering Nanjing University of Aeronautics and Astronautics The George W.Woodruff School of Mechanical Engineering Georgia Institute of Technology

A new decentralized control for aircraft engines is proposed. In the proposed control approach, aircraft engines are considered as uncertain large-scale systems composed of interconnected uncertain subsystems. For each subsystem, the time-varying uncertainty, including parameter disturbances and interconnections in/between subsystems, is depicted by a class of general nonlinear functions. A fractional robust decentralized control with two parts, the nominal one and the fractional one, is presented. The nominal control guarantees the asymptotical stability of the engine system without uncertainty. The fractional part aims at overcoming the influences of uncertainty. Compared to the previous studies, the presented control provides not only an extra flexibility for the system performance tuning by the fraction-type gain but also a facility for the control input calculation. The proposed control approach is applied to a turbofan engine with two subsystems. The computer simulation shows that, in the flight envelope, the fractional control not only guarantees the closed-loop system uniform boundedness and ultimate uniform boundedness but also shows good economy.

关键词： Aircraft engines large-scale systems Robust decentralized control Uncertainty Uniform boundedness Uniform ultimate boundedness

Preparation of WO3 thin films by dip film-drawing for photoelectrochemical performance

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Chinese Journal of Chemical Engineering 2019年第5期27卷 1207-1211页

作者： Dongbo Xu Lili Li Weiqiang Fan Fagen Wang Hongye Bai Baodong Mao Weidong Shi School of Energy and Power Engineering Jiangsu UniversityZhenjiang 212013China School of Chemistry and Chemical Engineering Jiangsu University. Zhenjiang 212013China

Here we report the WO3 thin films on F-doped SnO2 conducting glass (FTO) substrates which were prepared by using dip film-drawing method. Dip film-drawing was a simple, convenient, economical method and in largescale to prepare photoanodes for future applications. The FTO substrates were dipped in tungstic acid solution then film-drawn included 3, 6, 9, 12 and 15 times for prepared different thicknesses of WO3 thin film photoanodes. Then the photoa no des were employed as the electrodes in photoelectrochemical property Keywords: WO3 thin films Dip film-drawing Photoelectrochemical Thicknesses large-scale measurements, which include scan linear sweep, repeated on/off illumination cycles, electrochemical impedanee spectroscopy and incident phot on to current conversion efficiency, respectively. The results showed that the WO3 thin films dipped 9 times with 175 nm thicknesses had the best photoelectrochemical performance of 0.067 mA·cm^-2 at 1.23 V versus RHE.

关键词： WO3 thin films Dip film-drawing Photoelectrochemical Thicknesses large-scale

Circulation Features Associated with the Record-breaking Typhoon Silence in August 2014

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Advances in Atmospheric Sciences 2018年第10期35卷 1321-1336页

作者： Jianpu BIAN Juan FANG Guanghua CHEN Chengji LIU Center for Monsoon System Research Institute of Atmospheric Physics Chinese Academy of Sciences Key Laboratory of Mesoscale Severe Weather (MOE) School of Atmospheric Sciences Nanjing University Department of Atmospheric and Oceanic Sciences University of California

Climatologically, August is the month with the most tropical cyclone(TC) formation over the western North Pacific(WNP) during the typhoon season. In this study, the reason for abnormal TC activity during August is discussed—especially August 2014, when no TCs formed. The large-scale background of August 2014 is presented, with low-level large-scale easterly anomalies and anticyclonic anomalies dominating over the main TC genesis region, a weak monsoon trough system,and a strong WNP subtropical high(WPSH), leading to significantly reduced low-level convergence, upper-level divergence,and mid-level upward motion. These unfavorable large-scale conditions suppressed convection and cyclogenesis. In August2014, equatorial waves were inactive within the negative phase of the Madden–Julian Oscillation(MJO), with fewer tropical disturbances. Although the low-level vorticity and convection of those disturbances were partly promoted by the convective envelopes of equatorial waves, the integral evolution of disturbances, as well as the equatorial waves, were suppressed when propagating into the negative MJO phase. Moreover, the upper-level potential vorticity(PV) streamers associated with anticyclonic Rossby wave breaking events imported extratropical cold and dry air into the tropics. The peripheral tropospheric dryness and enhanced vertical wind shear by PV streamer intrusion combined with the negative MJO phase were responsible for the absence of TC formation over the WNP in August 2014.

关键词： large-scale pattern cyclogenesis MJO equatorial waves Rossby wave breaking