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C_2h_4-O_2混合气体直接起爆的临界能量

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爆炸与冲击 2012年第2期32卷 113-120页

作者：张博 lee J h s 白春华北京理工大学爆炸科学与技术国家重点实验室北京100081 Department of Mechanical Engineering McGill University

主要基于化学动力学和Ng模型,对C2h4-O2混合气体的爆轰胞格尺寸进行预测;结合lee表面积能量模型,预测物质在不同初始压力和化学当量比的条件下,直接起爆引起球面爆轰的临界起爆能量。直接起爆实验主要采用高压电点火提供起爆能量,起爆... 详细信息

主要基于化学动力学和Ng模型,对C2h4-O2混合气体的爆轰胞格尺寸进行预测;结合lee表面积能量模型,预测物质在不同初始压力和化学当量比的条件下,直接起爆引起球面爆轰的临界起爆能量。直接起爆实验主要采用高压电点火提供起爆能量,起爆能量通过放电过程中电流的输出信号确定。结果表明,理论预测与实验值较吻合。首先,通过化学动力学计算得出ZND模型的爆轰参数,利用Ng模型得出爆轰胞格尺寸与ZND诱导区长度之间的比例因数A在不同初始压力与当量比的条件下分别为:A=43.815(1+p1/p0)-0.123 71和A=8.531exp(φ/3.135)+28.644,在此基础上对爆轰胞格尺寸进行定量预测。胞格尺寸的理论预测与实验结果吻合。其次,把爆轰胞格尺寸作为中间特征参数并结合lee的表面积能量模型,提出可以预测临界起爆能量的定量模型,并得出C2h4-O2混合气体直接起爆的临界起爆能量与初始压力和化学当量比的参量拟合关系分别为Ec=0.332(p1/p0)-2.017和Ec=exp[3.951(φ-1.401)2-1.9]。

关键词：爆炸力学临界起爆能直接起爆 C2h4-O2混合气体胞格尺寸化学动力学电火花点火

高浓度氩气稀释对C2h2-2．5O2气体直接起爆临界能量影响的实验研究

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高压物理学报 2012年第1期26卷 55-62页

作者：张博 lee John h s 白春华北京理工大学爆炸科学与技术国家重点实验室北京100081 Department of Mechanical Engineering McGill University Montreal H3A 2K6Canada

采用高压电点火进行直接起爆,通过放电过程中电流的输出信号确定起爆能量,实验测定了C2h2-2.5O2气体和加入摩尔浓度为70%氩气的C2h2-2.5O2混合气体直接起爆的临界起爆能量,研究了高浓度氩气稀释对C2h2-2.5O2混合物临界起爆能量的影响。... 详细信息

采用高压电点火进行直接起爆,通过放电过程中电流的输出信号确定起爆能量,实验测定了C2h2-2.5O2气体和加入摩尔浓度为70%氩气的C2h2-2.5O2混合气体直接起爆的临界起爆能量,研究了高浓度氩气稀释对C2h2-2.5O2混合物临界起爆能量的影响。实验测得的混合物临界起爆能量实验值与lee等人的表面积能量理论值基本吻合。研究表明:C2h2-2.5O2气体和加入摩尔浓度为70%氩气的C2h2-2.5O2混合气体的临界起爆能量均依赖于初始压力,并呈反相关指数关系;在相同实验条件下,高浓度氩气稀释极大提高了混合气体直接起爆的临界起爆能量。分析认为,由于临界起爆能量正比于诱导区长度的3次方,因此在相同初始压力下,高浓度氩气的稀释增加了C2h2-2.5O2混合气体爆轰诱导区长度,并最终导致其临界起爆能量的显著上升。

关键词：直接起爆临界起爆能量诱导区长度电火花点火氩气

superplasticity of fine-grained Mg-10Li alloy prepared by severe plastic deformation and understanding its deformation mechanisms

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Journal of Magnesium and Alloys 2024年第1期12卷 316-331页

作者： h.T.Jeong s.W.lee W.J.Kim Department of Materials science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul 121-791Republic of Korea

The superplastic behavior and associated deformation mechanisms of a fine-grained Mg-10.1 Li-0.8Al-0.6Zn alloy(LAZ1011)with a grain size of 3.2μm,primarily composed of the BCCβphase and a small amount of the hCPαphase,were examined in a temperature range of 473 K to 623 *** microstructural refinement of this alloy was achieved by employing high-ratio differential speed *** best superplasticity was achieved at 523 K and at strain rates of 10^(-4)-5×10^(-4)s^(-1),where tensile elongations of 550±600%were *** the heating and holding stage of the tensile samples prior to tensile loading,a significant increase in grain size was observed at temperatures above 573 ***,it was important to consider this effect when analyzing and understanding the superplastic deformation behavior and *** the investigated strain rate range,the superplastic flow at low strain rates was governed by lattice diffusion-controlled grain boundary sliding,while at high strain rates,lattice diffusion-controlled dislocation climb creep was the rate-controlling deformation *** was concluded that solute drag creep is unlikely to *** the late stages of deformation at 523 K,it was observed that grain boundary sliding led to the agglomeration of theαphase,resulting in significant strain *** mechanism maps were constructed forβ-Mg-Li alloys in the form of 2D and 3D formats as a function of strain rate,stress,temperature,and grain size,using the constitutive equations for various deformation mechanisms derived based on the data of the current tests.

关键词： Magnesium-lithium alloy superplasticity severe plastic deformation Grain size Grain growth

术中麻醉方法对全膝置换术后镇痛效果和吗啡使用的影响:一项网状荟萃分析

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临床骨科杂志 2024年第1期27卷 136-136页

作者： YOO J D hUh M h lee s h 胡孔足(摘译) 不详

作者使用网状荟萃分析方法,纳入40项研究。结果发现,切口周围浸润麻醉结合隐神经阻滞麻醉对全膝置换患者术后第1、2天镇痛效果最好,对术后第1、3天吗啡需要量最少。股神经阻滞麻醉术后第3天镇痛效果最好,布比卡因神经阻滞麻醉术后第2天... 详细信息

作者使用网状荟萃分析方法,纳入40项研究。结果发现,切口周围浸润麻醉结合隐神经阻滞麻醉对全膝置换患者术后第1、2天镇痛效果最好,对术后第1、3天吗啡需要量最少。股神经阻滞麻醉术后第3天镇痛效果最好,布比卡因神经阻滞麻醉术后第2天吗啡需要量最少。

关键词：神经阻滞麻醉浸润麻醉荟萃分析镇痛效果布比卡因术中麻醉全膝置换吗啡

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 have been widely used owing to their high energy density, extended cycle lifespan, and minimal self-discharge 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

Construction of a broad-host-range Anderson promoter series and particulate methane monooxygenase promoter variants expand the methanotroph genetic toolbox

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synthetic and systems Biotechnology 2024年第2期9卷 250-258页

作者： Etash h.Bhat Jessica M.henard spencer A.lee Dustin Mchalffey Mahith s.Ravulapati Elle V.Rogers Logan Yu David skiles Calvin A.henard Department of Biological sciences and BioDiscovery Institute University of North TexasDentonTXUSA

Methanotrophic bacteria are currently used industrially for the bioconversion of methane-rich natural gas and anaerobic digestion-derived biogas to valuable *** bacteria may also serve to mitigate the negative effects of climate change by capturing atmospheric greenhouse *** genetic tools have previously been developed for genetic and metabolic engineering of ***,the available tools for use in methanotrophs are significantly underdeveloped compared to many other industrially relevant bacteria,which hinders genetic and metabolic engineering of these *** such,expansion of the methanotroph genetic toolbox is needed to further our understanding of methanotrophy and develop biotechnologies that leverage these unique microbes for mitigation and conversion of methane to valuable ***,we determined the copy number of three broad-host-range plasmids in Methylococcus capsulatus Bath and Methylosinus trichosporium OB3b,representing phylogenetically diverse Gammaproteobacterial and Alphaproteobacterial methanotrophs,***,we show that the commonly used synthetic Anderson series promoters are functional and exhibit similar relative activity in *** and *** OB3b,but the synthetic series had limited ***,we mutagenized the native *** particulate methane monooxygenase promoter and identified variants with activity that expand the activity range of synthetic,constitutive promoters functional not only in ***,but also in Escherichia ***,the tools developed here advance the methanotroph genetic engineering toolbox and represent additional synthetic genetic parts that may have broad applicability in Pseudomonadota bacteria.

关键词： Methanotroph Methane monooxygenase Promoter Metabolic engineering synthetic biology

MgO-attached graphene nanosheet(MgO@GNs)reinforced magnesium matrix nanocomposite with superior mechanical,corrosion and biological performance

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International Journal of Minerals,Metallurgy and Materials 2024年第9期31卷 2062-2076页

作者： s.Abazari A.shamsipur h.R.Bakhsheshi-Rad M.s.soheilirad F.Khorashadizade s.s.Mirhosseini Department of Materials and Metallurgical Engineering Amirkabir University of TechnologyTehran ***Iran Iranian National standards Organization of hormozgan HormozganIran Advanced Materials Research Center Department of Materials EngineeringNajafabad BranchIslamic Azad UniversityNajafabadIran Department of Materials and Metallurgical Engineering Iran University of Science and TechnologyTehranIran

Magnesium(Mg)alloys are gaining great consideration as body implant materials due to their high biodegradability and ***,they suffer from low corrosion resistance and antibacterial *** this research,semi-powder metallurgy followed by hot extrusion was utilized to produce the magnesium oxide@graphene nanosheets/magnesium(MgO@GNs/Mg)composite to improve mechanical,corrosion and cytocompatibility *** have revealed that the incorporation of MgO@GNs nanohybrids into Mg-based composite enhanced microhardness and compressive *** vitro,osteoblast cell culture tests show that using MgO@GNs nanohybrid fillers enhances osteoblast adhesion and apatite *** presence of MgO@GNs nanoparticles in the composites decreased the opening defects,micro-cracks and micro-pores of the composites thus preventing the penetration of the corrosive solution into the *** demonstrated that the MgO@GNs/Mg composite possesses excellent antibacterial properties because of the combination of the release of MgO and physical damage to bacterium membranes caused by the sharp edges of graphene nanosheets that can effectively damage the cell wall thereby facilitating penetration into the bacterial lipid ***,the MgO@GNs/Mg composite with high mechanical strength,antibacterial activity and corrosion resistance is considered to be a promising material for load-bearing implant applications.

关键词： metal matrix composites MgO@GNs nanohybrid strengthening mechanisms antibacterial activity biocompatibility

A Comprehensive Review on Charging Topologies and Power Electronic Converter solutions for Electric Vehicles

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Journal of Modern Power systems and Clean Energy 2024年第3期12卷 675-694页

作者： Abdelfatah Ali hossam h.h.Mousa Mostafa F.shaaban Maher A.Azzouz Ahmed s.A.Awad the Department of Electrical Engineering American University of Sharjah26666 SharjahUnited Arab Emirates the Department of Electrical Engineering South Valley University83523 QenaEgypt the Department of Electrical and Computer Engineering University of WindsorWindsorON N9B 3P4 Canada Electrical Engineering Department Qatar UniversityDoha 2713Qatar Department of Electrical and Computer Engineering Sultan Qaboos UniversityMuscat123Oman

Electric vehicles(EVs)are becoming more popular worldwide due to environmental concerns,fuel security,and price *** performance of EVs relies on the energy stored in their batteries,which can be charged using either AC(slow)or DC(fast)***,EVs can also be used as mobile power storage devices using vehicle-to-grid(V2G)*** electronic converters(PECs)have a constructive role in EV applications,both in charging EVs and in ***,this paper comprehensively investigates the state of the art of EV charging topologies and PEC solutions for EV *** examines PECs from the point of view of their classifications,configurations,control approaches,and future research prospects and their impacts on power *** can be classified into various topologies:DC-DC converters,AC-DC converters,DC-AC converters,and AC-AC *** address the limitations of traditional DC-DC converters such as switching losses,size,and high-electromagnetic interference(EMI),resonant converters and multiport converters are being used in high-voltage EV ***,power-train converters have been modified for high-efficiency and reliability in EV *** paper offers an overview of charging topologies,PECs,challenges with solutions,and future trends in the field of the EV charging station applications.

关键词： Charging station charging topology electric vehicle power electronic converter vehicle-to-grid

A high-Order Localized Artificial Diffusivity scheme for Discontinuity Capturing on 1D Drift-Flux Models for Gas-Liquid Flows

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Advances in Applied Mathematics and Mechanics 2024年第1期16卷 47-74页

作者： Adyllyson h.Nascimento Eugenio s.Rosa Department of Energy School of Mechanical EngineeringUniversity of CampinasCampinasBrazil

A computational code is developed for the numerical solution of onedimensional transient gas-liquid flows using drift-flux models,in isothermal and also with phase change *** these two-phase models,classical upwind schemes such as Roe-and Godunov-type schemes are generally difficult to derive and expensive to use,since there are no treatable analytic expressions for the Jacobian matrix,eigenvalues and eigenvectors of the system of *** the other hand,the highorder compact finite difference scheme becomes an attractive alternative on these occasions,as it does not make use of any wave propagation information from the system of *** present paper extends the localized artificial diffusivity method for high-order compact finite difference schemes to solve two-phase flows with *** numerical method has simple formulation,straightforward implementation,low computational cost and,most importantly,*** numerical methodology proposed is validated by solving several numerical examples given in the *** simulations are sixth-order accurate and it is shown that the proposed numerical method provides accurate approximations of shock waves and contact *** is an essential property for simulations of realistic mass transport problems relevant to operations in the petroleum industry。

关键词： Compressible two-phase flows drift-flux model localized artificial diffusivity highorder numerical methods