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Bilayer Compounded Polytetrafluoroethylene Membrane for Enhanced Oil-Water Emulsion Separation

Chinese Journal of Polymer Science 2024年第6期42卷 838-850页

作者： Yu-Liang Yang tai-ran zhang Yan-Ting Han Shao-Yun Guo Qin-Gong Rong Jia-Bin Shen State Key Laboratory of Polymer Materials Engineering Polymer Research Institute of Sichuan UniversitySichuan Provincial Engineering Laboratory of Plastic/Rubber Complex Processing TechnologyChengdu610065China West China Hospital/West China School of Nursing Sichuan UniversityChengdu610041China Shandong Senrong New Materials Co. Ltd.Zibo256401China

In order to achieve efficient and durable oil-water emulsion separation,the membranes possessing high separation efficiency and mechanical strength attract extensive attention and are in great demand.In present study,a kind of polytetrafluoroethylene(PTFE)-based bilayer membrane was fabricated by electrospinning fibrous PTFE(fPTFE)on an expanded PTFE(ePTFE)substrate.The morphological observation revealed that the fibrous structure of the fPTFE layer could be tailored by controlling the formulation of spinning solution.The addition of appropriate polyoxyethylene(PEO)would make the fibers in the fPTFE layer finer and more uniform.As a result,the compounded membrane exhibited a small pore size of approximately 1.25µm and a substantial porosity nearing 80%.This led to super-hydrophobicity,characterized by a high water contact angle(WCA)of 149.8°,and facilitated rapid oil permeation.The water-in-oil emulsion separation experiment further confirmed that the compounded membrane not only had a high separation efficiency closing 100%,but such an outstanding separation capacity could be largely retained,either through multiple cycles of use or through strong acid(pH=1),strong alkali(pH=12),or high-temperature(100°C)treatment.Additionally,the mechanical behavior of the bilayer membrane was basically contributed by that of each layer in terms of their volume ratio.More significantly,the poor creep resistance of fPTFE layer was suppressed by compounding with ePTFE substrate.Hence,this study has laid the groundwork for a novel approach to create PTFE-based compounded membranes with exceptional overall characteristics,showing promise for applications in the realm of emulsion separation.

关键词： ePTFE Electrospinning membrane Bilayer compounding Emulsion separation

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Recent Progress in Improving Rate Performance of Cellulose-Derived Carbon Materials for Sodium-Ion Batteries

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Nano-Micro Letters 2024年第8期16卷 102-147页

作者： Fujuan Wang Tianyun zhang Tian zhang Tianqi He Fen ran State Key Laboratory of Advanced Processing and Recycling of Non‑Ferrous Metals Lanzhou University of TechnologyLanzhou 730050People’s Republic of China School of Materials Science and Engineering Lanzhou University of TechnologyLanzhou 730050People’s Republic of China School of Mechanical and Electronical Engineering Lanzhou University of TechnologyLanzhou 730050People’s Republic of China

Cellulose-derived carbon is regarded as one of the most promising candidates for high-performance anode materials in sodium-ion batteries;however,its poor rate performance at higher current density remains a challenge to achieve high power density sodium-ion batteries.The present review comprehensively elucidates the structural characteristics of cellulose-based materials and cellulose-derived carbon materials,explores the limitations in enhancing rate performance arising from ion diffusion and electronic transfer at the level of cellulose-derived carbon materials,and proposes corresponding strategies to improve rate performance targeted at various precursors of cellulose-based materials.This review also presents an update on recent progress in cellulose-based materials and cellulose-derived carbon materials,with particular focuses on their molecular,crystalline,and aggregation structures.Furthermore,the relationship between storage sodium and rate performance the carbon materials is elucidated through theoretical calculations and characterization analyses.Finally,future perspectives regarding challenges and opportunities in the research field of cellulose-derived carbon anodes are briefly highlighted.

关键词： Cellulose Hard carbon Anode materials Rate performance Sodium-ion batteries

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Reliability ensemble averaging reduces surface wind speed projection uncertainties in the 21st century over China

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Advances in Climate Change Research 2024年第2期15卷 222-229页

作者： Zheng-tai zhang Chang-Ai XU Key Laboratory for Semi-Arid Climate Change of the Ministry of Education College of Atmospheric SciencesLanzhou UniversityLanzhou 730000China

Accurate prediction of future surface wind speed(SWS)changes is the basis of scientific planning for wind turbines.Most studies have projected SWS changes in the 21st century over China on the basis of the multi-model ensemble(MME)of the 6th Coupled Model Intercomparison Project(CMIP6).However,the simulation capability for SWS varies greatly in CMIP6 multi-models,so the MME results still have large uncertainties.In this study,we used the reliability ensemble averaging(REA)method to assign each model different weights according to their performances in simulating historical SWS changes and project the SWS under different shared socioeconomic pathways(SSPs)in 2015-2099.The results indicate that REA considerably improves the SWS simulation capacity of CMIP6,eliminating the overestimation of SWS by the MME and increasing the simulation capacity of spatial distribution.The spatial correlations with observations increased from 0.56 for the MME to 0.85 for REA.Generally,REA could eliminate the overestimation of the SWS by 33%in 2015-2099.Except for southeastern China,the SWS generally decreases over China in the near term(2020-2049)and later term(2070-2099),particularly under high-emission scenarios.The SWS reduction projected by REA is twice as high as that by the MME in the near term,reaching-4%to-3%.REA predicts a larger area of increased SWS in the later term,which expands from southeastern China to eastern China.This study helps to reduce the projected SWS uncertainties.

关键词： Surface wind speed Uncertainty Multi-model ensemble Reliability ensemble averaging CMIP6

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Neighboring optimal guidance using higher-order dynamics approximation with application to orbital injection problem

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Chinese Journal of Aeronautics 2024年第5期37卷 426-440页

作者： Xinglun CHEN ran zhang Huifeng LI School of Astronautics Beihang UniversityBeijing 100191China

Neighboring optimal guidance,a method to obtain a suboptimal guidance law by approximately solving the first-order necessary conditions based on a nominal trajectory,is widely used in the aerospace field due to its high computational efficiency and low resource usage.For more advanced scenarios,the existing methods still have a problem that the guidance accuracy and optimality will seriously degrade when the actual state largely deviates from the nominal trajectory.This is mainly caused by the approximate description of the first-order conditions in terms of total flight time and nonlinear constraints.To address this problem,a higher-order neighboring optimal guidance method is proposed.First,a novel total flight time updating strategy,together with a normalized time scale,is presented that transforms the optimal problem with free total flight time into a more tractable optimal problem with fixed total flight time.Then,using the vector partial derivative method,a higher-order approximation is adopted,instead of the first-order approximation,to accurately describe the nonlinear dynamical and terminal constraints,thus obtaining a polynomially constrained quadratic optimal problem.Finally,to numerically solve the polynomially constrained quadratic optimal problem,a Newton-type iterative algorithm based on the orthogonal decomposition is designed.Through the iterative solution within each guidance period,the corrections to control quantities and total flight time are generated.The proposed method is applied to a launch vehicle orbital injection problem,and simulation results show that it achieves high accuracy of orbital injection and optimality of performance index.

关键词： Optimal control Neighboring optimal guidance Launch vehicles Orbital injection Higher-order approximation

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Compensated acceleration feedback based active disturbance rejection control for launch vehicles

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Chinese Journal of Aeronautics 2024年第4期37卷 464-478页

作者： Xiaoyan zhang Wenchao XUE Zibo LIU ran zhang Huifeng LI Key Laboratory of Systems and Control Institute of Systems ScienceAcademy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China School of Astronautics Beihang UniversityBeijing 100191China

In this paper, the attitude tracking and load relief control problems against wind disturbances and uncertain aerodynamics as well as the engine thrust of launch vehicles are studied.Firstly, a framework of Compensated Acceleration Feedback based Active Disturbance Rejection Control(CAF-ADRC) is established to achieve both desired attitude tracking and load relief performances. In particular, the total disturbance that includes the effects caused by both aerocoefficient perturbations and disturbances is estimated by constructing an Extended State Observer(ESO) to achieve attitude tracking. Furthermore, combined with the normal acceleration due to the engine thrust, the accelerometer measurement is also compensated to enhance the load relief effect.Secondly, the quantitative analysis of ESO and the entire closed-loop system are studied. It can be concluded that the desired attitude tracking and load relief performances can be achieved simultaneously under the proposed approach. Besides, tuning laws of the proposed approach are systematically given, which are divided into ESO, Proportional Derivative(PD) and Compensated Acceleration Feedback(CAF) modules. Moreover, the performances under CAF-ADRC approach can be better than those under CAF based PD(CAF-PD) approach by tuning load relief gain.Finally, the approach presented is applied to a typical control problem of launch vehicles with wind disturbances and parameter uncertainties.

关键词： Launch vehicles Uncertainty analysis Active disturbance rejection control(ADRC) Load relief control Extended state observer(ESO)

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Uncertainty and sensitivity analysis of in-vessel phenomena under severe accident mitigation strategy based on ISAA-SAUP program

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Nuclear Science and Techniques 2024年第1期35卷 108-123页

作者： Hao Yang Ji-Shen Li Zhi-ran zhang Bin zhang Jian-Qiang Shan School of Nuclear Science and Technology Xi’an Jiaotong UniversityXi’an 710049China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China

The phenomenology involved in severe accidents in nuclear reactors is highly complex.Currently,integrated analysis programs used for severe accident analysis heavily rely on custom empirical parameters,which introduce considerable uncertainty.Therefore,in recent years,the field of severe accidents has shifted its focus toward applying uncertainty analysis methods to quantify uncertainty in safety assessment programs,known as“best estimate plus uncertainty(BEPU).”This approach aids in enhancing our comprehension of these programs and their further development and improvement.This study concentrates on a third-generation pressurized water reactor equipped with advanced active and passive mitigation strategies.Through an Integrated Severe Accident Analysis Program(ISAA),numerical modeling and uncertainty analysis were conducted on severe accidents resulting from large break loss of coolant accidents.Seventeen uncertainty parameters of the ISAA program were meticulously screened.Using Wilks'formula,the developed uncertainty program code,SAUP,was employed to carry out Latin hypercube sampling,while ISAA was employed to execute batch calculations.Statistical analysis was then conducted on two figures of merit,namely hydrogen generation and the release of fission products within the pressure vessel.Uncertainty calculations revealed that hydrogen production and the fraction of fission product released exhibited a normal distribution,ranging from 182.784 to 330.664 kg and from 15.6 to 84.3%,respectively.The ratio of hydrogen production to reactor thermal power fell within the range of 0.0578–0.105.A sensitivity analysis was performed for uncertain input parameters,revealing significant correlations between the failure temperature of the cladding oxide layer,maximum melt flow rate,size of the particulate debris,and porosity of the debris with both hydrogen generation and the release of fission products.

关键词： Gen-III PWR Severe accident mitigation Wilks’formula Hydrogen Fission products Uncertainty and sensitivity analysis

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An in-situ polymerized interphase engineering for high-voltage allsolid- state lithium-metal batteries

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Nano Research 2024年第4期17卷 2687-2692页

作者： Lu Nie Shaojie Chen Mengtian zhang Tianyi Gao Yuyao zhang ran Wei Yining zhang Wei Liu School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China Tsinghua-Berkeley Shenzhen Institute&Tsinghua Shenzhen International Graduate School Tsinghua UniversityShenzhen 518055China

All-solid-state lithium batteries(ASSLBs)have attracted great interest due to their promising energy density and strong safety.However,the interface issues,including large interfacial resistance between electrode and electrolyte and low electrochemical stability of solid-state electrolytes against high-voltage cathodes,have restricted the development of high-voltage ASSLBs.Herein,we report an ASSLB with stable cycling by adopting a conformal polymer interlayer in-situ formed at the Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)–cathode interfaces.The polymer can perfectlyﬁll the voids and create a stable interface contact between LLZTO and cathodes.In addition,the electric field across the polymer interlayer is reduced compared with pure solid polymer electrolyte(SPE),which facilitates the electrochemical stability with high-voltage cathode.The all-solid-state Li|LLZTO-SPE|LiFe_(0.4)Mn_(0.6)PO_(4)(LMFP)cells achieve a low interface impedance,high specific capacity,and excellent cycling performance.This work presents an effective and practical strategy to rationally design the electrode–electrolyte interface for the application of high-voltage ASSLBs.

关键词： all-solid-state lithium batteries interface contact electric field electrochemical stability

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Relationship between the Stratospheric Arctic Vortex and Surface Air Temperature in the Midlatitudes of the Northern Hemisphere

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Journal of Meteorological Research 2024年第1期38卷 39-52页

作者： Xue ran Dingzhu HU Yang zhang Mei-Chen LIU Key Laboratory of Meteorological Disaster Ministry of Education(KLME)/Joint International Research Laboratory of Climate and Environmental Change(ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)Nanjing University of Information Science&TechnologyNanjing 210044 School of Atmospheric Sciences Nanjing UniversityNanjing 210023

It is known that different relationships exist between the strength and displacement of the stratospheric polar vortex(SPV),and the surface air temperature(SAT)patterns in Eurasia and North America,but the mechanisms behind these relationships remain unclear,especially on an interannual timescale.Based on empirical orthogonal function(EOF)analysis using NCEP reanalysis data over 1958–2018,this study attempts to ascertain the relationship between the SPV intensity and displacement over the Arctic and the SATs in the midlatitudes of the Northern Hemisphere.Our results indicate that a strengthened SPV corresponds to an SAT increase in Eurasia and a decrease in eastern North America and Greenland.When the SPV is shifted towards Eurasia,however,a corresponding SAT increase occurs in both North America and Eurasia,with a larger increase in North America than in Eurasia.Specifically,a strengthened SPV tends to correspond to a positive North Atlantic Oscillation-like circulation in the troposphere with negative geopotential height(GH)anomalies in Greenland and eastern North American continent and positive GH anomalies to the north of 45°N in Eurasia,which corresponds to lower SATs in North America than in Eurasia.However,when the SPV shifted towards Eurasia,it was accompanied by a positive Pacific/North American-like pattern with a deepened Aleutian low,which corresponds to the increasing SATs in North America.These tropospheric circulation changes are related to the response of tropospheric planetary wave activity to the SPV.A strengthened SPV corresponds to the weakening of tropospheric planetary wave-1 waves,which is accompanied by a negative GH in North America but a positive GH in Eurasia.If the SPV shifted towards Eurasia,the tropospheric planetary wave-1(-2)waves strengthened(weakened),and the combined effects of the planetary wave-1 and wave-2 waves would cause positive GH anomalies in both Eurasia and North America.

关键词： stratospheric polar vortex surface air temperature teleconnection patterns planetary waves

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Yolk free egg substitute improves the serum phospholipid profile of mice with metabolic syndrome based on lipidomic analysis

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Food Science and Human Wellness 2024年第1期13卷 482-493页

作者： Zhihui Yu Lingyu Fan Fei tai Lixin zhang Xiaoyu zhang Yisheng Chen College of Food Science and Engineering Shanxi Agricultural UniversityTaigu 030801China Insitute of Food Nutrition and Safety Shanxi Agricultural UniversityTaiyuan 030031China Shanxi Key Laboratory of Edible Fungi for Loess Plateau Taigu 030801China

In this study,the impacts of egg consumption on mice model of metabolic syndrome(Met S)were comparatively investigated.Mice were divided into five groups(n=8):normal diet group(ND),high-fat diet group(HFD),HFD with whole egg group(WE),HFD with free-yolk egg substitute group(YFES),and HFD with lovastatin group(Lov).Main biochemical indexes and a non-targeted lipidomic analysis were employed to insight the lipid profile changes in serum.It was revealed that WE could significantly improve serum biochemical indexes by reducing body weight,low-density lipoprotein cholesterol(LDL-C)and total cholesterol(TC),while increasing high-density lipoprotein cholesterol.YFES exhibited remarkably better performance in increasing phosphatidylglycerol and phosphatidic acids,while decreasing phosphatidylinositol than WE.A total of 50 differential lipids biomarkers tightly related to glycerophospholipids metabolism were screened out.Carnitine C18:2 and C12:1,SM(d18:0/12:0),and SM(d18:1/14:1)were significantly upregulated in YFES compared to WE.YFES reduced expression of SREBP-1c and Cpt1a,while did not affect the expression of PPAR-α.Sphingomyelin biomarkers were positively related to the TC(|r|>0.6),while PPAR-αwas negatively correlated with triglyceride and LDL-C levels.To sum up,YFES attenuated HFD-induced Met S by improving the serum phospholipids,which account for its modulation of glycerophospholipid metabolism.

关键词： Metabolic syndrome Whole egg Yolk free egg substitute Serum Lipidomics

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A Residual Frequency Offset Estimation Method Based on range Migration Fitting

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Journal of Beijing Institute of Technology 2024年第2期33卷 103-110页

作者： Liting zhang Hao Huan ran Tao Xiaogang Tang School of Information and Electronics Beijing Institute of Technology School of Aerospace Information Space Engineering University

Recently, researchers have proposed an emitter localization method based on passive synthetic aperture. However, the unknown residual frequency offset(RFO) between the transmitter and the receiver causes the received Doppler signal to shift, which affects the localization accuracy. To solve this issue, this paper proposes a RFO estimation method based on range migration fitting. Due to the high frequency modulation slope of the linear frequency modulation(LFM)-modulation radar signal, it is not affected by RFO in range compression. Therefore, the azimuth time can be estimated by fitting the peak value position of the pulse compression in range direction.Then, the matched filters are designed under different RFOs. When the zero-Doppler time obtained by the matched filters is consistent with the estimated azimuth time, the given RFO is the real RFO between the transceivers. The simulation results show that the estimation error of azimuth distance does not exceed 20 m when the received signal duration is not less than 3 s, the pulse repetition frequency(PRF) of the transmitter radar signal is not less than 1 k Hz, the range detection is not larger than 1 000 km, and the signal noise ratio(SNR) is not less than –5 d B.

关键词： passive localization range migration fitting (RMF) residual frequency offset (RFO)

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