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Phosphorus Flame Retardant Modified Aramid Nanofiber Separator for Advanced Safety Lithium-Sulfur Batteries

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SSRN 2024年

作者： Liu, Jianwei Zhu, Lei Wang, Jianan Chai, Qinqin Sun, Shiyi Chen, Xin Wang, Xue Zhang, Yating Yan, Wei College of Chemistry and Chemical Engineering Xi’an University of Science and Technology Shaanxi Xi’an710054 China Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiao tong University Shaanxi Xi’an710049 China Xianggui Manganese Industry Co. Ltd. Shaanxi Province Ziyang County725300 China School of Physics and Electrical Engineering Weinan Normal University Shaanxi Weinan714099 China Xi'an Hantang Analysis & Test Co. Ltd Xi’an710201 China

Safety concerns have perennially impeded the large-scale implementation of high-energy-density storage systems. Nevertheless, because the intrinsic drawbacks of the commercial polyolefin separator are poor thermal stability and low flammability with a large thermal contribution, the development of an advanced separator that solves the above questions is imminent. In this work, gradient flame-retardant aramid nanofiber separators (T-PMIA) were synthesized by a single-step electrospinning method. The T-PMIA separator demonstrates excellent Li-ion diffusion and proficiently suppresses the "shuttle effect" through its plentiful multilevel beaded structure and robust anchoring of soluble polysulfides (Li2Sx), achieved by optimizing the functional groups P and -P-O. Moreover, the enhanced separator exhibits a rapid self-extinguishing feature (self-extinguishing time: 0.20 s) and impressive mechanical properties (tensile strength of up to 12.58 MPa and puncture force of 0.94 N). Accordingly, the T-PMIA separator still showed a stable cycling performance (maintain 901.7 mAg-1 after 100 cycles) even at high temperature (80 ℃). This simple separator strategy offers a highly competitive option for the large-scale production of high-safety lithium-sulfur (Li-S) batteries. This uncomplicated separator strategy presents a compelling solution for the large-scale production of high-safety lithium-sulfur (Li-S) batteries © 2024, The Authors. All rights reserved.

关键词： Separators

Phenomenon of fog formation and flow characteristics of droplet-vapor-gas mixture in a cooler-condenser

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Phenomenon of fog formation and flow characteristics of drop...

ASME 2019 International Mechanical engineering Congress and Exposition, IMECE 2019

作者： Gu, Hongfang Guo, Qiwei Li, Changsong Zhou, Qing State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an Shaanxi China

ISBN: (纸本)9780791859452

Fog formation occurs in the process of condensation in the presence of non-condensable gas if the bulk temperature is lower than its saturation temperature (supersaturated). The phenomena of fogging is the formation of small condensate particles mixing with the vapor/gas stream, which creates potential problems of the vapor/gas/condensate separation and environmental pollution. Therefore, understanding of fogging mechanism and prevention of fog droplet entrainment are one of technical concerns for design and operation of cooler-condensers in the process industry. This paper presents the experimental study and numerical simulation of shell-side condensation with fog formation using a mixture of steam/non-condensable gas. The experimental data were collected on the two tube bundles (modified plastic tubes and stainless steel tubes). Using a high-speed photograph technique, the phenomenon of fog formation and flow characteristics of vapor/droplet transport were recorded over a wide range of test conditions. The numerical analysis of film and dropwise condensation, fog formation and droplet particle transport were simulated using different tube geometry and material, and flow velocity of air/droplet mixture. Based on simulation results, a new droplet trapping parameter is proposed to assess the optimal parameters of heat exchanger structural and operation conditions. Comparisons show that the numerical analysis results have a good agreement with experimental data and observations. These findings provide fundamental approach to account for the effect of fog formation, film and dropwise condensation, and droplet transport crossflow in cooler-condensers. Copyright © 2019 ASME.

关键词： Drops

Numerical Investigation of the Thermal Response to Skin Tissue during Laser Lipolysis

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Journal of Thermal Science 2018年第5期27卷 470-478页

作者： CHEN Bin ZHANG Yue LI Dong State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University

Laser lipolysis can effectively treat obesity and its associated diseases, such as hypertension, fatty liver, and hyperlipidemia. However, currently available invasive laser lipolysis, which transmits laser to a fiber-optic catheter inserted into the subcutaneous tissue for irradiation through an incision, may cause hematomas, infections, and empyrosis. The current study presents a novel, noninvasive approach for laser lipolysis, which directly irradiates the intact skin surface without an incision and preferentially targets adipose tissue at the near-infrared band. High laser energy is necessary to damage adipocytes; however, this may carbonate and burn the dermis. Therefore, the introduction of skin cooling is essential to avoid unwanted hyperthermal injury and improve the threshold of radiant exposure. In the current study, we investigated a novel noninvasive approach assisted with skin cooling by establishing a homogeneous multi-layer skin model. In this method, light propagation in the skin was simulated by using the Monte Carlo method. Skin cooling was employed before laser irradiation to protect the epidermis from thermal damage, which was treated as a boundary condition based on Newton's law. The numerical results showed that the photons were deposited in the adipose layer more than in the other layers. Laser can effectively destroy adipose tissue at an energy density of >200 J/cm^2 at 1210 nm wavelength, whereas at least 300 J/cm^2 is required at 1064 nm to achieve the same effect. In this experiment, at >5 s pulse width, the selectivity of adipose was not obvious. Moreover, the results indicated that 60 ms R134a or R404a spray can effectively reduce the temperature of the epidermis. R404a exhibited a stronger cooling effect than R134a. Cold air cooling at -10 °C for 10 s could effectively decrease the skin temperature, and deeper cooling could be achieved by cold air cooling compared with cryogen spray cooling.

关键词： laser lipolysis Nd：YAG laser multi-layer skin model skin cooling

Melt droplet fragmentation behavior during fuel-coolant interaction 18

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Melt droplet fragmentation behavior during fuel-coolant inte...

18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2019

作者： Li, Gen Feng, Haobo Wen, Panpan Zhang, Jun Wang, Jinshi Yan, Junjie State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

During a severe accident of nuclear reactor, the fuel-coolant interaction occurs at the relocation stage of corium melt. Such a mode of contact can result in vigorous thermal interactions, intense steam generation and, potentially, steam explosions. The thermal processes, in their turn, largely depend on hydrodynamic behavior. When melt is pouring into coolant pool, the melt jet fragments into large droplets or blobs, named the primary breakup. The droplets or blobs will experience secondary breakup as a result of shock wave at steam explosion. Either the primary or secondary breakup is governed by interface hydrodynamic instabilities. The droplet size distribution, which affects fuel-coolant areas, is important for evaluating heat transfer and debris coolability. In this study, we modelled melt drops deformation and fragmentation using a meshless Lagrangian MPS method. Fragments amount and size distribution were compared under different Weber numbers, and fragments drag coefficient were also analyzed. The results indicate that the melt drops breakup process could be divided into two phases: initial deformation and fragmentation phase governed by flow inertial force and the subsequent fragments coalescence phase under the impact of fluid surface tension. Fragments amount increased in fragmentation phase but decreased in coalescence phase. A large amount of fragments has a normalized diameter of 0.01 - 0.03, but a small amount of large size fragments (d/d0 > 0.04) also appeared as the crescent-shaped melt broke up and small fragments coalesced. The drag coefficient decreased with time during drop deformation period, and then reached a stable value. It has no significant difference among cases with different Weber numbers. © 2019 American Nuclear Society. All rights reserved.

关键词： Hydrodynamics

Experimental study of auto-ignition of dimethyl ether at low-temperatures and low-pressures 12

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Experimental study of auto-ignition of dimethyl ether at low...

12th Asia-Pacific Conference on Combustion, ASPACC 2019

作者： Huang, Wenlin Sun, Wuchuan Wu, Honghuan Qin, Xiaokang Jiang, Xue Zhang, Yingjia Huang, Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

Dimethyl ether (DME) is a property of alternative fuels to attract due to the special molecular structure in terms of either scientific study or engine application. However, the lack of fundamental data at low pressures and low temperatures impedes to understand thoroughly the chemistry of DME. Ignition delay times of DME/"air" mixtures with various equivalence ratios of 0.5 - 5.0 were measured in a shock tube at pressure of 3.0 atm over temperatures of 625 - 1200 K. Aramco Mech 2.0 was selected to reproduce the experimental observation. In general, the kinetic model remains an uncertainty in predicting the reactivity of DME at equivalence ratios below 2.0 but it tends much better at equivalence ratios over 3.0. Unlike the model predictions, the experimental data did not show obvious NTC behavior for the mixtures with equivalence ratios of 0.5 and 1.0. The selected model almost fails to capture the four-stage ignition feature for the mixtures with equivalence of 2.0 even considering the hot spot caused by pre-ignition energy release. © Asia-Pacific Conference on Combustion, ASPACC *** right reserved.

关键词： Ethers

Theoretical Analysis on the Lifetime of Sessile Droplet Evaporation

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Theoretical Analysis on the Lifetime of Sessile Droplet Evap...

作者： Shen, Yang Cheng, Yongpan Xu, Jinliang Zhang, Kai Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy North China Electric Power University Beijing102206 China School of Energy Power & Mechanical Engineering North China Electric Power University Beijing102206 China

There are two stages for a sessile droplet evaporation on the solid substrate, one is the "constant contact radius" (CR) mode, the other is the "constant contact angle" (CA) mode. In this paper, the theoretical model is built up for sessile droplet evaporation for the two modes, the lifetime of evaporating droplet is obtained under different initial contact radius, initial contact angle and critical contact angle for mode transition. It is found that in the CR mode, the variation of initial contact angle is nonlinear with the time. For both CR and CA modes the lifetime is proportional to R02 (R0 is the initial contact radius of droplet) for two modes. When the critical contact angle for mode transition from CR to CA is increased, the lifetime for CR mode is decreased while the lifetime for CA mode is increased, and the overall lifetime is also increased. This result may be of great significance for sessile droplet evaporation. © Springer Nature Switzerland AG 2020.

关键词： Evaporation

Boosted Photocatalytic Co2 Reduction by Induced Electromotive Force in Rotating Magnetic Field

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SSRN 2023年

作者： Lu, Danchen Ren, Yuqi Yang, Ya Cheng, Miao Wang, Ke Wang, Nan Liu, Maochang Zhou, Jiancheng Chen, Wenshuai Li, Naixu School of Chemistry and Chemical Engineering Southeast University No.2 Dongnandaxue Road Jiangsu Nanjing211189 China CAS Center for Excellence in Nanoscience Beijing Key Laboratory of Micro-nano Energy and Sensor Beijing Institute of Nanoenergy and Nanosystems Chinese Academy of Sciences Beijing101400 China Key Laboratory of Bio-Based Material Science and Technology Ministry of Education Northeast Forestry University No. 26 Hexing Road Harbin150040 China International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University No.28 Xianning West Road Shaanxi Xi'An710049 China

Charge separation plays a crucial role in semiconductor-based photocatalytic CO2 conversion. Herein, we report a unique induced electric field, which can actively manipulate carrier behavior at the minuscule, leading to significantly boosted photocatalytic CO2 reduction in H2O vapor. The success relies on the development a monolithic photocatalyst made of a copper foam substrate and nanosized ZnO/NiO/Au heterostructures that can effectively couple a special rotating magnetic field (RMF). Specifically, the copper foam cuts the magnetic induction line, leading to the periodic generation of induced electric field. This induced electric field could significantly increase the carriers' density by preventing their recombination. Moreover, NiO and Au as the active sites for oxidation and reduction, respective, synergistically magnify this effect. As a result, compared with the photocatalytic reaction without adding RMF, the utilization rate of photogenerated electrons increases by 5.24 times after coupling RMF, with the yield of CO and CH4 improved by 5.50 times and 5.18 times. This strategy by integrating unique RMF into the reaction system provides new insights for improving photocatalytic CO2 conversion. © 2023, The Authors. All rights reserved.

关键词： Carbon dioxide

Physics-Based Probabilistic Assessment of Creep-Fatigue Failure for Pressurized Components by Extended Direct Steady Cycle Analysis-Driven Neural Network

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SSRN 2022年

作者： Wang, Xiaoxiao Ma, Zhiyuan Yang, Jie Chen, Haofeng Xuan, Fuzhen Department of Mechanical & Aerospace Engineering University of Strathclyde James Weir Building 75 Montrose Street GlasgowG1 1XJ United Kingdom Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai200093 China School of Mechanical and Power Engineering East China University of Science and Technology Shanghai200237 China

To achieve a high-reliability design with a feasible balance between accuracy and efficiency, the physics-based probabilistic assessment for creep-fatigue failure is proposed under the probabilistic Linear Matching Method (pLMM) framework. At the physical level, the structural failure mechanism is reflected in the prepared training database, which is generated by the direct method, extended Direct Steady Cycle Analysis (eDSCA) procedures. And to efficiently express the relationship between design parameters and structural responses implicitly, the extended DSCA-driven neural network (EDDNN) is built with the superior fitting quality of damage and lifetime. With the benchmarks of pressurized structures provided, the applicability of the proposed probabilistic analysis approach in solving practical problems is demonstrated, where the reliability-based evaluation diagram is established according to different requirements. Furthermore, a novel data classification scheme is proposed to deal with the randomness in creep damage-dominated probabilistic assessment. © 2022, The Authors. All rights reserved.

关键词： Failure (mechanical)

Compositional Variations in Highly Active Ptsn/Al2o3 Catalysts Derived from Molecular Complexes

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SSRN 2023年

作者： He, Qian Xu, Chaokai Tan, Shengdong Tang, Yaxin Xi, Shibo Yao, Bingqing Wade, Austin Zhao, Binbin Lu, Shangchen Tian, Mingjiao He, Chi Ma, Lu Fu, Xingjie Shi, Jiwei Lu, Jiong Howe, Alexander G.R. Dai, Sheng Luo, Guangfu Du, Yankun Department of Material Science and Engineering College of Design and Engineering National University of Singapore 9 Engineering Drive 1 EA #03-09 Singapore117575 Singapore Department of Materials Science and Engineering Guangdong Provincial Key Laboratory of Computational Science and Material Design Southern University of Science and Technology Guangdong Shenzhen518055 China 1 Pesek Road Jurong Island 627833 Singapore Thermo Fisher Scientific 5350 NW Dawson Creek Drive HillsboroOR United States State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China Brookhaven National Laboratory UptonNY11973 United States Department of Chemistry National University of Singapore 12 Science Drive 2 117549 Singapore Key Laboratory for Advanced Materials Joint International Research Laboratory of Precision Chemistry and Molecular Engineering School of Chemistry and Molecular Engineering East China University of Science & Technology Shanghai200237 China

We investigated the industrially important PtSn/Al2O3 catalysts prepared with uniform particle sizes (~ 1 nm) and varied compositions using molecular complexes of Pt(II) and Sn(II). Our best catalyst, with a Sn:Pt ratio of around 2, exhibited a high initial propylene productivity of about 1.1 mol C3H6 (g catalyst)-1 h-1. Elaborate electron microscopy studies revealed significant compositional variations in the catalyst, highlighting the practical challenges in achieving or confirming the theoretically predicted optimum Sn:Pt ratio. It is also found that the catalytic activities correlate well with the Pt dispersion, suggesting the structure-insensitive nature of the dehydrogenation reaction applies in these ultrasmall Pt-Sn nanoparticles. The presence of Pt-rich particles in the catalysts did not produce noticeable degradations in the reaction selectivity, indicating a wide composition range for Pt-Sn nanoparticles to be effective at the 1 nm size range. These findings emphasize the importance of detailed analysis of compositional distributions for understanding nanoalloys. © 2023, The Authors. All rights reserved.

关键词： Electron microscopy