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Mesoporous molecular sieve confined phase change materials with high absorption,enhanced thermal conductivity,and cooling energy charging/discharging capacity

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Frontiers of Materials Science 2024年第1期18卷 1-14页

作者： Qi Zhang Chongyang Liu Xuehong Wu Xueling Zhang jun song School of Energy and Power Engineering Zhengzhou University of Light IndustryZhengzhou 450007China

The biggest challenge for organic phase change materials(PCMs)used in cold energy storage is to maintain high heat storage capacity while reducing the leakage risk of PCMs during the phase transition *** is crucial for expanding their applications in the more demanding cold storage *** this study,novel formstable low-temperature composite PCMs are prepared with mesoporous materials,namely SBA-15 and CMK-3(which are prepared using the template method),as supporting matrices and dodecane as the *** to the combined effects of capillary forces within mesoporous materials and interactions among dodecane molecules,both dodecane/SBA-15 and dodecane/CMK-3 exhibit outstanding shape stability and thermal cycling stability even after 200 heating/cooling *** comparison to those of dodecane/SBA-15,dodecane/CMK-3 exhibits superior cold storage performance and higher thermal ***,the phase transition temperature of dodecane/CMK-3 is-8.81℃ with a latent heat of 122.4 J·g^(-1).Additionally,it has a thermal conductivity of 1.21 W·m^(-1)·K^(-1),which is 9.45 times that of dodecane *** these highlight its significant potential for applications in the area of cold energy storage.

关键词： cold energy storage phase change material mesoporous molecular sieve CMK-3 SBA-15 cooling energy charging/discharging capacity

Research on high energy efficiency and low bit-width floating-point type data for abnormal object detection of transmission lines

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Global Energy Interconnection 2024年第3期7卷 324-335页

作者： Chen Wang Guozheng Peng Rui song jun Zhang Li Yan China Electric Power Research Institute Beijing 100192P.R.China Information&Telecommunications Company State Grid Shandong Electric Power CompanyJinan 250001P.R.China

Achieving a balance between accuracy and efficiency in target detection applications is an important research *** detect abnormal targets on power transmission lines at the power edge,this paper proposes an effective method for reducing the data bit width of the network for floating-point *** performing exponent prealignment and mantissa shifting operations,this method avoids the frequent alignment operations of standard floating-point data,thereby further reducing the exponent and mantissa bit width input into the training *** enables training low-data-bit width models with low hardware-resource consumption while maintaining *** tests were conducted on a dataset of real-world images of abnormal targets on transmission *** results indicate that while maintaining accuracy at a basic level,the proposed method can significantly reduce the data bit width compared with single-precision *** suggests that the proposed method has a marked ability to enhance the real-time detection of abnormal targets in transmission ***,a qualitative analysis indicated that the proposed quantization method is particularly suitable for hardware architectures that integrate storage and computation and exhibit good transferability.

关键词： Power edge Data format Quantification Compute-in-memory

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Experimental and numerical investigation of the impacts of rotor tip-rake on excitation forces of pump-jet propulsors

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Journal of Hydrodynamics 2024年第1期36卷 142-157页

作者： Xue-qin Ji Xiao-song Zhang Chen-jun Yang Xiao-qian Dong State Key Laboratory of Ocean Engineering Marine Numerical Experiment CentreSchool of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China CSSC Shanghai Marine Energy Saving Technology Co. Ltd.Shanghai200011China China Ship Scientific Research Center Shanghai Branch Shanghai200011China

The tip-clearance flow in a pump-jet propulsor exerts great impacts on the fluctuating pressures and resultant unsteady forces,which are important sources of structural vibrations and radiated noise *** blade geometry close to the tip is an important factor determining the vortex strength in the tip-clearance *** the open-water condition,the effects of raking the rotor tips on the duct-surface fluctuating pressures and the resultant unsteady forces acting on different components of the propulsor are investigated via physical model experiments and the numerical solution of Reynolds-averaged Navier-Stokes(RANS)equations coupled with the SST k-ωturbulence *** measured and simulated results of hydrodynamic pressures are consistent to each other,and the simulated flows help better understand why the fluctuating pressures change with the tip *** strong fluctuations of duct-surface pressures are caused by intensive tip separation *** duct-surface pressure fluctuations are effectively reduced by using the rake distribution near the tip towards blade back side and,for the combination of the five-bladed rotor and the seven-bladed stator,the resultant unsteady horizontal(and vertical)forces acting on the duct and stator are also reduced;while increasing rake leads to negative effect on pressure fluctuations and unsteady horizontal(and vertical)forces acting on all the components of the propulsor.

关键词： Pump-jet tip-clearance tip-rake fluctuating pressures excitation forces

S-scheme regulated Ni_(2)P-NiS/twinned Mn_(0.5)Cd_(0.5)S hetero-homojunctions for efficient photocatalytic H_(2)evolution

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Journal of Materials Science & Technology 2024年第2期169卷 148-157页

作者： Qiqi Zhang Zhen Wang Yuhang song jun Fan Tao Sun Enzhou Liu School of Chemical Engineering/Xi’an Key Laboratory of Special Energy Materials Northwest UniversityXi’an 710069China

Effective bulk phase and surface charge separation is critical for charge utilization during the photo-catalytic energy conversion *** this work,the ternary Ni_(2)P-NiS/twinned Mn_(0.5)Cd_(0.5)S(T-MCS)nanohybrids were successfully constructed via combining Ni_(2)P-NiS with T-MCS solid solution for visible light photocatalytic H_(2)evolution.T-MCS is composed of zinc blende Mn_(0.5)Cd_(0.5)S(ZB-MCS)and wurtzite Mn_(0.5)Cd_(0.5)S(WZ-MCS)and those two alternatively arranged crystal phases endow T-MCS with excellent bulk phase charge separation performance for the slight energy level difference between ZB-MCS and WZ-MCS.S-scheme carriers transfer route between NiS and T-MCS can accelerate the interfacial charge separation and retain the active electrons and holes,meanwhile,co-catalyst Ni_(2)P as electron receiver and proton reduction center can further optimize the H_(2)evolution reaction kinetics based on the surface Schottky barrier *** above-formed homo-heterojunctions can establish multiple charge transfer channels in the bulk phase of T-MCS and interface of T-MCS and Ni_(2)*** the synergistic effect of twinned homojunction,S-scheme heterojunction,and Schottky barrier,the ternary Ni_(2)P-NiS/T-MCS com-posite manifested an H_(2)production rate of 122.5 mmol h^(-1)g^(-1),which was 1.33,1.24,and 2.58 times higher than those of the NiS/T-MCS(92.4 mmol h^(-1)g^(-1)),Ni_(2)P/T-MCS(98.4 mmol h^(-1)g^(-1)),and T-MCS(47.5 mmol h^(-1)g^(-1)),*** work demonstrates a promising strategy to develop efficient sul-fides photocatalyst toward targeted solar-driven H_(2)evolution through homo-heterojunction engineering.

关键词： Photocatalytic H_(2)evolution Twinned Mn_(0.5)Cd_(0.5)S Homojunction S-scheme heterojunction Schottky barrier

Molecular crowding electrolytes for stabilizing Zn metal anode in rechargeable aqueous batteries

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Chinese Chemical Letters 2024年第7期35卷 445-451页

作者： Li Lin song-Lin Tian Zhen-Yu Hu Yu Zhang Li-min Chang Jia-jun Wang Wan-Qiang Liu Qing-Shuang Wang Fang Wang School of Materials Science and Engineering Changchun University of Science and TechnologyChangchun 130022China School of Life Science and Technology Changchun University of Science and TechnologyChangchun 130022China Key Laboratory of Preparation and Applications of Environmental Friendly Materials of the ministry of Education Jilin Normal UniversityChangchun 130103China Zhongshan Institute of Changchun University of Science and Technology Zhongshan 528437China

A solid electrolyte interphase(SEI)with a robust mechanical property and a high ionic conductivity is imperative for high-performance zinc metal ***,it is difficult to form such a SEI directly from an *** this work,a molecular crowding effect is based on the introduction of Zn(OTF)_(2)and Zn(ClO_(4))_(2)to 2 mol/L ZnSO_(4)*** and experiments indicate that the Zn(OTF)_(2)and Zn(ClO_(4))_(2)not only create a molecularly crowded electrolyte environment to promote the interaction of Zn^(2+)and OTF^(-),but also participate in the reduction to construct a robust and high ionic-conductive SEI,thus promoting metal zinc deposition to the(002)crystal *** this molecular crowding electrolyte,a high current density of 1 mA/cm^(2)can be obtained by assembling symmetric batteries with Zn as the anode for over 1000 *** in a temperature environment of-10℃,a current density of 1 mA/cm^(2)can be obtained by assembling symmetric batteries with Zn for over 200 ***//Bi_(2)S_(3)/VS4@C cells achieve a CE rate of up to 99.81%over 1000 ***,the utilization of a molecular crowding electrolyte is deemed a highly effective approach to fabricating a sophisticated SEI for a zinc anode.

关键词： Zinc ion batteries Anode Electrolyte Solid electrolyte interphase Molecular crowding effect

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A New Method for the Aging Evaluation of Oil-Paper Insulation Using η-Butanol and Methanol

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 717-726页

作者： Jianyi Wang Yuanxiang Zhou jun Liu Zhaowei Wang song Bai Jiayu Lu Department of High Voltage China Electric Power Research InstituteBeijing 100192China State Key Laboratory of Power Grid Environmental Protection Beijing 100192China Electrical Engineering Department Tsinghua UniversityBeijing 100084China Solar Storage Division of State Key Lab of Power System and Generation Equipment School of Electrical EngineeringXinjiang UniversityUrumqi 830047China State Grid Wuwei Electric Power Supply Company Wuwei 733000China

To improve the accuracy and efficiency of the aging life prediction and assessment of transformer oil-paper insulation,and to make up for the deficiencies of traditional characterizers,such as 2-furfural,carbon monoxide,and carbon dioxide,a method for the simultaneous determination of methanol,ethanol,n−propanol,and η-butanol in oil with a single injection is established by headspace-gas chromatography-mass *** measured results show that the determination limits of the four alcohol characterizers can be controlled to 10μg/kg *** on this method,the change patterns of the above four alcohols with thermal aging time and degree of polymerization are obtained through thermal aging experimental ***,η-propanol,and η-butanol in oil indicate nearly linear correlations with thermal aging time and degree of polymerization,similar to that of *** analyzing 52 sets of measured data of 500 kV EHV transformers in operation,η-butanol is found to have excellent performance,and a new method to evaluate the aging state of oil-paper insulation employing η-butanol and methanol is proposed along with the aging attention value *** measured data of 500 kV EHV transformers in operation indicate that the combination of η-butanol and methanol as the preferred characterizers can effectively compensate for the shortcoming of traditional characterizers in the early stages of aging,and the feasibility of the method is *** possible pathways for the generation of η-butanol by cellulose cleavage during the aging of oil-paper are proposed from the chemical structure of cellulose.

关键词： Aging characterization determination method methanol η-butanol oil-paper insulation 500 kV transformers

Gas film/regenerative composite cooling characteristics of the liquid oxygen/liquid methane (LOX/LCH4) rocket engine

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第8期25卷 631-649页

作者： Xinlin LIU jun SUN Zhuohang JIANG Qinglian LI Peng CHENG Jie song Science and Technology on Scramjet Laboratory College of Aerospace Science and EngineeringNational University of Defense TechnologyChangsha 410073China

The thermal protection of rocket engines is a crucial aspect of rocket engine *** this paper,the gas film/regenerative composite cooling of the liquid oxygen/liquid methane(LOX/LCH4)rocket engine thrust chamber was investigated.A gas film/regenerative composite cooling model was developed based on the Grisson gas film cooling efficiency formula and the one-dimensional regenerative cooling *** accuracy of the model was validated through experiments conducted on a 6 kg/s level gas film/regenerative composite cooling thrust ***,key parameters related to heat transfer performance were *** results demonstrate that the model is sufficiently accurate to be used as a preliminary design *** temperature rise error of the coolant,when compared with the experimental results,was found to be less than 10%.Although the pressure drop error is relatively large,the calculated results still provide valuable guidance for heat transfer *** addition,the performance of composite cooling is observed to be superior to regenerative *** the gas film flow rate results in higher cooling efficiency and a lower gas-side wall ***,the position at which the gas film is introduced greatly impacts the cooling *** optimal introduction position for the gas film is determined when the film is introduced from a single row of *** optimal introduction position results in a more uniform wall temperature distribution and reduces the peak ***,it is observed that a double row of holes,when compared to a single row of holes,enhances the cooling effect in the superposition area of the gas film and further lowers the gas-side wall *** results provide a basis for the design of gas film/regenerative composite cooling systems.

关键词： Liquid oxygen/liquid methane(LOX/LCH4)rocket engine Gas film cooling Regenerative cooling Heat transfer characteristics

Effect of wire diameter compression ratio on drawing deformation of micro copper wire

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Transactions of Nonferrous Metals Society of China 2024年第8期34卷 2605-2618页

作者： Tao HUANG Han-jiang WU Ke-xing song Yan-min ZHANG Yan-jun ZHOU Shao-lin LI School of Materials Science and Engineering Henan University of Science and TechnologyLuoyang 471023China Henan Key Laboratory of Advanced Conductor Materials Institute of MaterialsHenan Academy of SciencesZhengzhou 450000China

A crystal plasticity finite element model was developed for the drawing deformation of pure copper micro wire,based on rate-dependent crystal plasticity *** impact of wire diameter compression ratio on the micro-mechanical deformation behavior during the wire drawing process was *** indicate that the internal deformation and slip of the drawn wire are unevenly distributed,forming distinct slip and non-slip ***,horizontal strain concentration bands develop within the drawn *** the wire diameter compression ratio increases,the strength of the slip systems and the extent of slip zones inside the deformation zone also ***,the fluctuating stress state,induced by contact pressure and frictional stress,results in a rough and uneven wire surface and diminishes the stability of the drawing process.

关键词： micro copper wire drawing deformation crystal plasticity finite element slip mode

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Multi-Time Scale Operation and Simulation Strategy of the Park Based on Model Predictive Control

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Energy Engineering 2024年第3期121卷 747-767页

作者： jun Zhao Chaoying Yang Ran Li Jinge song Grid Center State Grid Shanxi Electric Power Company Electric Power Science Research InstituteTaiyuan030000China

Due to the impact of source-load prediction power errors and uncertainties,the actual operation of the park will have a wide range of fluctuations compared with the expected state,resulting in its inability to achieve the expected *** paper constructs an operating simulation model of the park power grid operation considering demand response and proposes a multi-time scale operating simulation method that combines day-ahead optimization and model predictive control(MPC).In the day-ahead stage,an operating simulation plan that comprehensively considers the user’s side comfort and operating costs is proposed with a long-term time scale of 15 *** order to cope with power fluctuations of photovoltaic,wind turbine and conventional load,MPC is used to track and roll correct the day-ahead operating simulation plan in the intra-day stage to meet the actual operating operation status of the ***,the validity and economy of the operating simulation strategy are verified through the analysis of arithmetic examples.

关键词： Demand response model predictive control multiple time scales operating simulation