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Convexification of hybrid AC-DC Optimal Power Flow with Line-Commutated Converters

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CsEE Journal of Power and Energy systems 2024年第2期10卷 617-628页

作者： hongyuan liang Zhigang Li J.h.Zheng Q.h.Wu s.h.ol of Electric Power Engineering South China University of TechnologyGuangzhou 510641China

Line-commutated converter (LCC)-based high-voltage DC (hVDC) systems.h.ve been integrated with bulk AC power grids for interregional transmission of renewable power. The nonlinear LCC model brings additional nonconvexity to optimal power flow (OPF) of hybrid AC-DC power grids. A convexification method for the LCC station model could address such nonconvexity but has rarely been discussed. We devise an equivalent reformulation for classical LCC station models that facilitates second-order cone convex relaxation for the OPF of LCC-based AC-DC power grids. We also propose sufficient conditions for exactness of convex relaxation with its proof. Equivalence of the proposed LCC station models and properties, exactness, and effectiveness of convex relaxation are verified using four numerical simulations. simulation results demonstrate a globally optimal solution of the original OPF can be efficiently obtained from relaxed model.

关键词： AC-DC power system convex relaxation linecommutated converter optimal power flow second-order cone programming

Graphdiyne(C_(n)h_(2n-2))as an"electron transfer bridge"boosting photocatalytic hydrogen evolution over Zn_(0.5)Co_(0.5)s/Mos_(2)s-s.h.me heterojunction

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Rare Metals 2024年第5期43卷 1999-2014页

作者： Mei Li Jing-Zhi Wang Zhi-liang Jin s.h.ol of Chemistry and Chemical Engineering North Minzu UniversityYinchuan 750021China s.h.ol of Chemistry and Chemical Engineering Ningxia Key Laboratory of Solar Chemical Conversion TechnologyKey Laboratory for Chemical Engineering and TechnologyState Ethnic Affairs CommissionNorth Minzu UniversityYinchuan 750021China

In the process of photocatalytic water cracking,the migration rate and utilization rate of photogenerated charges determine the hydrogen evolution performance of the *** this paper,a carbon isotope superconducting material graphdiyne(GDY)is prepared by mechanical ball milling and introduced into the s-s.h.me heterojunction Zn_(0.5)Co_(0.5)s/Mos_(2)inorganic *** terms of hydrogen evolution kinetics,GDY acts as an electron bridge,not only accelerating the migration of photogenerated carriers but also improving the utilization of photogenerated ***,the large twodimensional layer provides more loading and anchoring points for Zn_(0.5)Co_(0.5)s/Mos_(2),which increases the number of active *** ternary composite catalyst 20%GDY/Zn_(0.5)Co_(0.5)s/Mos_(2)(20-GCsM)generates 69.94μmol of hydrogen(5 h)in triethanolamine *** is 2.97 and1.80 times.h.gher than Zn_(0.5)Co_(0.5)s and Zn_(0.5)Co_(0.5)s/Mos_(2),*** the cyclic experiment,it still has stable hydrogen evolution performance after standing for24 h(under dark conditions).In addition,the potential mechanism of photocatalytic hydrogen evolution is demonstrated through in-situ X-ray photoelectron *** work provides a reference for further research in the field of introducing carbon materials into photocatalytic systems and improving the utilization of photogenerated charges.

关键词： Graphdiyne s-s.h.me heterojunction Electron transfer bridge hydrogen production

A Preliminary Comparative study on the Centering Algorithms for CassiniIss NAC Images

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Research in Astronomy and Astrophysics 2024年第10期24卷 58-65页

作者： T.liang Q.-F.Zhang G.-M.Liu W.-h.Zhu C.-s.Wang Department of Computer science Jinan UniversityGuangzhou 510632China sino-French Joint Laboratory for Astrometry Dynamics and Space ScienceJinan UniversityGuangzhou 510632China s.h.ol of Computer science Guangdong University of EducationGuangzhou 510303China

Obtaining high precision is an important consideration for astrometric studies using images from the Narrow Angle Camera(NAC)of the Cassini Imaging science subsystem(Iss).selecting the best centering algorithm is key to enhancing astrometric *** this study,we compared the accuracy of five centering algorithms:Gaussian fitting,the modified moments method,and three point-spread function(PsF)fitting methods(effective PsF(ePsF),PsFEx,and extended PsF(x PsF)from the Cassini Imaging Central Laboratory for Operations(CICLOPs)).We assessed these algorithms using 70 Iss NAC star field images taken with CL1 and CL2 filters across different stellar *** ePsF method consistently demonstrated the highest accuracy,achieving precision below 0.03 pixels for stars of magnitude *** to the previously considered best,the modified moments method,the e PsF method improved overall accuracy by about 10%and 21%in the sample and line directions,***,the xPsF model provided by CICLOPs.h.d lower precision than the ***,the ePsF exhibits an improvement in measurement precision of 23%and 17%in the sample and line directions,respectively,over the *** discrepancy might be attributed to the xPsF focusing on photometry rather than *** findings.h.ghlight the necessity of constructing PsF models specifically tailored for astrometric purposes in NAC images and provide guidance for enhancing astrometric measurements using these Iss NAC images.

关键词： methods:analytical techniques:image processing stars:imaging astrometry

A functional hydrogenase mimic that catalyzes robust h_(2) evolution spontaneously in aqueous environment

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Nano Research 2024年第5期17卷 3942-3949页

作者： Ningning song Zhanjun Guo shuo Wang Yongli Li Yunpeng Liu Meishuai Zou Minmin liang Experimental Center of Advanced Materials School of Materials Science&EngineeringBeijing Institute of TechnologyBeijing 100081China s.h.ol of Materials science&Engineering Beijing Institute of TechnologyBeijing 100081China Institute of high Energy Physics Chinese Academy of SciencesBeijing 100049China

Although great progress.h.s been made in improving hydrogen production,highly efficient catalysts,which are able to produce hydrogen in a fast and steady way at ambient temperature and pressure,are still in large ***,we report a[NiCo]-based hydrogenase mimic,NiCo_(2)O_(4) nanozyme,that can catalyze robust hydrogen evolution spontaneously in water without external energy input at room *** hydrogenase nanozyme facilitates water splitting reaction by forming a three-center Ni-Oh-Co bond analogous to the[NiFe]-hydrogenase reaction by using aluminum as electron donor,and realizes.h.drogen evolution with a high production rate of 915 L·h^(-1) per gram of nanozymes,which is.h.ndreds of times.h.gher than most of the natural hydrogenase or hydrogenase ***,the NiCo_(2)O_(4) nanozyme can robustly disrupt the adhesive oxidized layer of aluminum and enable the full consumption of electrons from *** contrast to the often-expensive synthetic catalysts that rely on rare elements and consume high energy,we envision that this NiCo_(2)O_(4) nanozyme can potentially provide an upgrade for current hydrogen evolution,accelerate the development of scale-up hydrogen production,and generate a clean energy future.

关键词： hydrogenase mimic nanozyme hydrogen evolution reaction aluminum activation water-splitting

Processing of a low-costγ-γ'NiPtAl coating with improved oxidation resistance

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Rare Metals 2024年第6期43卷 2832-2841页

作者： Yan Jiang liang-liang Wei Jian he hong-Bo Guo s.h.ol of Materials science and Engineering Beihang UniversityBeijing 100191China Key Laboratory of high-Temperature structural Materials and Protective Coatings Ministry of Industry and Information TechnologyBeihang UniversityBeijing 100191China

A novelγ-γ'(Ni solid solution—Ni_(3)Al)NiPtAl coating was produced on advanced single-crystal(sC)superalloy N5 by electroplating of a thin Pt coating with~3μm in thickness followed by heat treatment at 1000℃in *** comparison,a traditionalγ-γ'NiPtAl coating was also produced by electroplating of a thick Pt coating with~6μm in thickness followed by heat treatment at 1100℃in *** novel coating has a mass gain of~0.5 mg·cm^(-2)after 100 h 1-h cyclic oxidation at 1150℃,showing better oxidation resistance than the traditional *** oxide scale mostly consisting ofα-Al_(2)O_(3)grew on the novel coating because the element Cr from the sC alloy substrate contributes to the formation ofα-Al_(2)O_(3).Pt content in the novel coating has significant effect on the oxidation *** optimized Pt content in the coating is about 16 at%,which is.h.lpful to reduce the diffusion of harmful elements from the substrate into the coating but also to reduce the cost of the coating.

关键词： γ-γ'NiPtAl coating Platinum Oxidation Al_(2)O_(3) superalloy

Masses of the conjectured h-dibaryon at different temperatures

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Chinese Physics C 2024年第8期48卷 83-93页

作者： liang-Kai Wu han Tang Ning Li Xin-Yang Wang s.h.ol of Physics and Electronic Engineering Jiangsu UniversityZhenjiang 212013China Center for Fundamental Physics School of Mechanics and PhysicsAnhui University of Science and TechnologyHuainan 232001China

We present a lattice QCD determination of masses of the conjectured h-dibaryon,denoted as mh,at nine different temperatures:T/T_(c)=0.24,0.63,0.76,0.84,0.95,1.09,1.27,1.52,and *** masses of baryons N,Σ,Ξ,andΛat different temperatures were also *** simulations were performed on an anisotropic lattice with N_(f)=2+1 flavours of clover fermion at a quark mass corresponding to mπ=384(4)*** thermal ensembles were provided by the FAsTsUM collaboration,whereas the zero temperature ensembles were provided by the hadspec *** also calculated the spectral density of the correlation function of those *** spectral density distributions show a rich peak structure at the lowest temperature;at intermediate temperatures,the mass values of those particles obtained by the extrapolation method reflect a two-peak *** the spectral density for the octet baryon becomes smooth at T/T_(c)=1.27,1.52,and 1.90,the spectral density for the h-dibaryon becomes smooth at T/T_(c)=*** T/T_(c)=0.24,the mass difference of the h-dibaryon andΛpair,expressed asΔm=m_(h)−2m_(Λ),was estimated to beΔm=−14.6(6.2)MeV,which suggests the existence of a bound h-dibaryon state.

关键词： lattice QCD h-dibaryon spectral function clover fermion finite temperature

Luminescence regulation of sb^(3+)in 0D hybrid metal halides by hydrogen bond network for optical anti-counterfeiting

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Opto-Electronic Advances 2024年第3期7卷 15-25页

作者： Dehai liang saif M.h.Qaid Xin Yang shuangyi Zhao Binbin Luo Wensi Cai Qingkai Qian Zhigang Zang Key Laboratory of Optoelectronic Technology&systems(Ministry of Education) Chongqing UniversityChongqing 400044China Department of Physics&Astronomy College of SciencesKing Saud UniversityP.O.Box 2455Riyadh 11451Saudi Arabia Department of Chemistry and Chemical Engineering Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong ProvinceShantou UniversityShantou 515063China Department of Oil Army Logistics Academy of PLAChongqing 401311China

The sb^(3+) doping strategy has been proven to be an effective way to regulate the band gap and improve the photophysical properties of organic-inorganic hybrid metal halides(OIhMhs).however,the emission of sb^(3+) ions in OIhMhs is primarily confined to the low energy region,resulting in yellow or red *** date,there are few reports about green emission of sb^(3+)-doped ***,we present a novel approach for regulating the luminescence of sb^(3+) ions in 0D C_(10)h_(2)_(2)N_(6)InCl_(7)·h_(2)O via hydrogen bond network,in which water molecules act as agents for hydrogen ***^(3+)-doped C_(10)h_(2)2N_(6)InCl_(7)·h_(2)O shows a broadband green emission peaking at 540 nm and a high photoluminescence quantum yield(PLQY)of 80%.It is found that the intense green emission stems from the radiative recombination of the self-trapped excitons(sTEs).Upon removal of water molecules with heat,C_(10)h_(2)_(2)N_(6)In_(1-x)sb_(x)Cl_(7) generates yellow emis-sion,attributed to the breaking of the hydrogen bond network and large structural distortions of excited *** water molecules are adsorbed by C_(10)h_(2)_(2)N_(6)In_(1-x)sb_(x)Cl_(7),it can subsequently emit green *** water-induced reversible emission switching is successfully used for optical security and information *** findings expand the under-standing of how the local coordination structure influences the photophysical mechanism in sb^(3+)-doped metal halides and provide a novel method to control the sTEs emission.

关键词： indium-based halides sb^(3+)doping hydrogen bonding network optical anti-counterfeiting

hierarchical FeO_(χ)h_(y)@Ni_(3)B hybrid for efficient alkaline oxygen evolution at high current density

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Journal of Energy Chemistry 2024年第7期94卷 599-607页

作者： Fuxi Liu Qing liang Zhenyu Li Meiqi Liu Nailin Yue Zizhun Wang Xu Zou Wei Zhang Key Laboratory of Automobile Materials Ministry of Education School of Materials Science&EngineeringElectron Microscopy CenterInternational Center of Future ScienceJilin Provincial International Cooperation Key Laboratory of High-Efficiency Clean Energy MaterialsJilin UniversityChangchun 130012JilinChina

Electrocatalysts with high activity and long-term durability are vital toward large-scale hydrogen pro-duction from electrocatalytic water ***,the self-supported electrode(FeO_(χ)h_(y)@Ni_(3)B/NF)with hierarchical heterostructure was simply prepared by using Ni_(3)B chunks grown on nickel foam as sub-strate to in situ form vertical FeO_(χ)h_(y)*** hybrid shows efficient oxygen evolution reaction activity with overpotentials as low as 267 and 249 mV at 100 mA cm^(-2)in 1 M KOh solution and 30 wt%KOh solution,***,it also exhibits excellent catalytic stability,sustaining catalysis at 500 mA cm^(-2)in 1 M KOh solution for 200 h,and even for 200 h at 1000 mA cm^(-2)in 30 wt%KOh *** experimental results reveal that the FeO_(χ)h_(y)@Ni_(3)B/NF is endowed with superhydrophilic and superaerophobic surface properties,which not only provide more mass transport channels,as well as facilitated the diffusion of reaction intermediates and gas ***,it holds faster reaction kinetics,more accessible active sites and accelerated electron transfer rates due to strong synergistic interactions attheheterogeneous interface.

关键词： FeO_(χ)h_(y)@Ni_(3)B/NF hybrid heterostructure Oxygen evolution reaction Electrocatalytic

Optimizing Average Electric Power During the Charging of Lithium-Ion Batteries Through the Taguchi Method

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Transactions of Tianjin University 2024年第2期30卷 152-166页

作者： Mohd h.s.Alrashdan Department of Electrical Engineering Al-Hussein Bin Talal UniversityMaan 71110Jordan

In recent times, lithium-ion batteries.h.ve been widely used owing to their high energy density, extended cycle lifespan, and minimal self-dis.h.rge rate. The design of high-speed rechargeable lithium-ion batteries faces a significant challenge owing to the need to increase average electric power during charging. This challenge results from the direct influence of the power level on the rate of chemical reactions occurring in the battery electrodes. In this study, the Taguchi optimization method was used to enhance the average electric power during the charging process of lithium-ion batteries. The Taguchi technique is a statistical strategy that facilitates the systematic and efficient evaluation of numerous experimental variables. The proposed method involved varying seven input factors, including positive electrode thickness, positive electrode material, positive electrode active material volume fraction, negative electrode active material volume fraction, separator thickness, positive current collector thickness, and negative current collector thickness. Three levels were assigned to each control factor to identify the optimal conditions and maximize the average electric power during charging. Moreover, a variance assessment analysis was conducted to validate the results obtained from the Taguchi analysis. The results revealed that the Taguchi method was an eff ective approach for optimizing the average electric power during the charging of lithium-ion batteries. This indicates that the positive electrode material, followed by the separator thickness and the negative electrode active material volume fraction, was key factors significantly infl uencing the average electric power during the charging of lithium-ion batteries response. The identification of optimal conditions resulted in the improved performance of lithium-ion batteries, extending their potential in various applications. Particularly, lithium-ion batteries with average electric power of 16 W and 17

关键词： Lithium-ion batteries Average electric power during charging Taguchi method COMsOL Multiphysics software C rate L27 orthogonal array