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Formation mechanism of interface reaction layer between microporous magnesia refractories and molten steel and its effect on steel cleanliness

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Journal of Iron and Steel Research International 2023年第9期30卷 1743-1754页

作者： wen-wen Zhang Wan Zheng wen yan Guang-qiang Li The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education Wuhan University of Science and TechnologyWuhan 430081HubeiChina Hubei Provincial Key Laboratory for New Process of Ironmaking and Steelmaking Wuhan University of Science and TechnologyWuhan 430081HubeiChina

The ceramic filter in continuous casting tundish can effectively improve the cleanliness of high-performance steel by regulating tundish flow field to promote the removal of inclusions and adsorbing or blocking fine inclusions in the molten steel into the *** interaction between microporous magnesia refractories used as tundish filter and molten interstitial-free(IF)steel at 1873 K was investigated to reveal the formation mechanism of their interface layer and its effect on steel cleanliness by laboratory research and thermodynamic *** results show that the magnesium–aluminum spinel layer at the interface between the molten IF steel and the microporous magnesia refractories is formed mainly by the reaction of MgO in the refractory with the[Al]and[O]in the molten steel,significantly reducing the total O content,the size and amount of inclusions of the molten *** addition,the interparticle phases of microporous magnesia refractories at high temperature can adsorb Al_(2)O_(3) and TiO_(2) inclusions in the molten steel into interparticle channels of the refractories to form high melting point spinel,impeding the further penetration of the molten *** a result,the consecutive interface layer of high melting point spinel between microporous magnesia refractories and molten steel can improve the cleanliness of the molten steel by adsorbing inclusions in the molten steel and avoid the direct dissolution of refractories of the tundish ceramic filter immersed in the molten steel,increasing their service life.

关键词： Tundish metallurgy Microporous magnesia refractory Interstitial-free steel Formation mechanism Interface reaction layer Inclusion removal

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Amino acids as indicators of seasonal variations in organic matter degradation in surface sediments from a shallow lake

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Journal of Environmental Sciences 2023年第9期131卷 1-10页

作者： yan wen wenqiang Zhang Baoqing Shan Research Center for Eco-Environmental Sciences Chinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China

Degradation of organic matter(OM)in sediments is a key link in nutrient cycling and sedimentation processes in *** aim of this study was to explore the degradation of OM in surface sediments of a shallow lake(Baiyangdian Lake,China)under seasonal temperature *** this,we used the amino acid-based degradation index(DI)and the spatiotemporal distribution characteristics and sources of *** OM in the lake mainly originated from freshwater aquatic plants and terrestrial C4 *** sediment at some sampling sites was affected by surrounding *** organic carbon and total nitrogen contents,and the total hydrolyzed amino acid concentrations in the sediments were highest in summer and lowest in *** lowest DI occurred in spring,which indicated that the OM in the surface sediment at this time was highly degraded and relatively stable,and the highest DI occurred in winter,which showed that the sediment was *** water temperature was positively correlated with the organic carbon content(p<0.01)and total hydrolyzed amino acids concentration(p<0.05).Seasonal variations in the overlying water temperature had a large effect on OM degradation in the lake *** results will facilitate the management and restoration of lake sediments that suffer from endogenous release of OM in a warming climate。

关键词： Sediment Organic matter Amino acid Temperature Degradation

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MODEL ANALYSIS AND PARAMETER EXTRACTION FOR MOS CAPACITOR INCLUDING QUANTUM MECHANICAL EFFECTS

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Journal of Computational Mathematics 2006年第3期24卷 401-411页

作者： Hai-yan Jiang Ping-wen Zhang LMAM CCSE and School of Mathematical Sciences.Peking University Beijing 100871 China

The high frequency CV curves of MOS capacitor have been studied. It is shown that semiclassical model is a good approximation to quantum model and approaches to classical model when the oxide layer is thick. This conclusion provides us an efficient （semiclassical） model including quantum mechanical effects to do parameter extraction for ultrathin oxide device. Here the effective extracting strategy is designed and numerical experiments demonstrate the validity of the strategy.

关键词： Poisson Equation SchrSdinger Equation MOS Capacitor Quantum Effect,Sensitivity Parameter Extraction.

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基于弹丸膛内运动参数和压力测试的火炮膛内燃气温度估算方法

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火工品 2025年第1期 51-54页

作者：赵煜华闫光虎肖霞严文荣梁磊西安近代化学研究所陕西西安710065

为了解决火炮膛内测试环境恶劣而导致发射药燃气温度测试难度大的问题,基于微波干涉仪、压力测试系统,结合发射药配方性能计算理论、装药内弹道性能计算模型等理论,建立了一种基于实测参数的火炮膛内燃气温度估算方法,并开展了试验研究... 详细信息

为了解决火炮膛内测试环境恶劣而导致发射药燃气温度测试难度大的问题,基于微波干涉仪、压力测试系统,结合发射药配方性能计算理论、装药内弹道性能计算模型等理论,建立了一种基于实测参数的火炮膛内燃气温度估算方法,并开展了试验研究。结果表明:火炮膛内燃气温度的最高值约为2631.8 K,随着弹丸运动迅速降低,弹丸出炮口时膛内燃气温度降低到约1858.4 K;建立的火炮膛内发射药燃气温度估算方法可以有效地获得火炮整个内弹道过程中火药燃气温度随时间的变化规律,为低烧蚀发射药及装药的研制提供了一种新的研究手段。

关键词：发射药膛内燃气温度估算方法微波干涉仪

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Non-constant Stationary Solutions to a Prey-predator Model with Diffusion

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Acta Mathematicae Applicatae Sinica 2009年第1期25卷 141-150页

作者： Ming yang wen-yan Chen Department of Mathematics Southeast University Nanjing 210096 China

In this paper, a nonlinear predator reproduction and prey competition model with diffusion is discussed. Some existence and non-existence results concerning non-constant positive steady-states are presented using topo... 详细信息

关键词： Prey-predator model steady states degree method energy method

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Synthesis, Crystal Structure and Biological Activities of 3-[2-(4-Fluoro-phenyl)-ethyl]-5-methyl-4-hydroxyl-4-methyl-7-methylsulfanyl-3,4-dihydro-pyrido[4,3-d]pyrimidine-8-carbonitrile

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Chinese Journal of Structural Chemistry 2007年第2期26卷 172-176页

作者： MO wen-yan HE Hong-Wu College of Chemistry Central China Normal University Wuhan 430079 China

The title compound, 3-[2-（4-fluoro-phenyl）-ethyl]-5-methyl-4-hydroxyl-4-methyl- 7-methylsulfanyl-3,4-dihydro-pyrido[4,3-d]pyrimidine-8-carbonitrile, has been prepared and detemined by single-crystal X-ray diffraction. The crystal belongs to the triclinic system, space group P1 with a = 6.8754（8）, b = 10.2617（12）, c = 13.3491（16） A, α = 93.163（2）, β = 96.704（2）, γ = 102.421（2）°, V= 910.35（19）A^3, Z= 2, Mr= 370.44, Dc= 1.351 g/cm^3,μ = 0.203 mm^-1,F（000） = 388, the final R = 0.0573 and wR = 0.1497. X-ray analysis reveals that the pyridine and pyrimidine rings are almost coplanar.

关键词： pyrido[4,3-d]pyrimidine synthesis crystal structure biological activities

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Effect of nano-carbon black content on wetting phenomenon of molten steel and alumina-carbon ceramic filter substrates

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Journal of Iron and Steel Research International 2024年第8期31卷 1900-1913页

作者： Jin-wen Song wen yan Zhe Chen Ying Liu Shao-song Hong The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina National-provincial Joint Engineering Research Center of High Temperature Materials and Lining Technology Wuhan University of Science and TechnologyWuhan 430081HubeiChina Jiangsu Sheng Nai New Materials Co. Ltd.Taizhou 225503JiangsuChina

The effect of nano-carbon black content(O,8 and 12 wt.%)on the wettability of molten steel on Al_(2)O_(3)-C substrates was investigated by the sessile drop wetting method at 1500℃ under argon *** the beginning of the wetting experiment,the contact angle decreased with the increase in nano-carbon black *** the wetting experiment progressed,FeAl_(2)0_(4) layer and sheet Al_(2)O_(3) layer were found at the interface between the molten steel and the Al_(2)O_(3)-C substrates with O and 8 wt.% nano-carbon black content,and the contact angle deceased with *** the content of nano-carbon black was 12 wt.%,a large number of nano-Al_(2)O_(3) whiskers were observed,which made the contact angle between the molten steel and Al_(2)O_(3)-C substrate become *** on the scanning electron microscope and energy dispersive spectrometry results,the formation mechanism of FeAl2O4 layer and Al_(2)O_(3) layer and the interfacial reaction mechanism were proposed.

关键词： Contact angle Nano-carbon black Al_(2)O_(3)-C substrate Molten steel Interfacial reaction

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Evidence of temperature-controlled dissolved inorganic nitrogen distribution in a shallow lake

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Journal of Environmental Sciences 2022年第12期34卷 105-114页

作者： yan wen wenqiang Zhang Baoqing Shan Jie Qu Research Center for Eco-Environmental Sciences Chinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China

Dissolved inorganic nitrogen(DIN) plays an important role in aquatic ecosystems as an available source of nitrogen(N). Despite recent advances in our understanding of the effects of climate change on DIN in coastal waters, shallow high-latitude lakes exposed to large seasonal temperature differences have received limited research attention. Therefore,in the present study, Baiyangdian Lake(BYDL) was selected as the study area, as a typical high latitude shallow lake in North China. Based on water and sediment samples collected in spring, summer and winter seasons, DIN accumulation in sedimentary pore water and DIN diffusion fluxes at the sediment-water interface were quantified under different temperature conditions. Correlation analysis was used to establish the effects of temperature on DIN concentration and diffusion in different media. Results show that the diffusion of DIN at the lake sediment-water interface exhibited a strongly positive relationship with temperature, suggesting that high temperature conditions lead to greater DIN release from sediments. Cold temperatures cause DIN accumulation in sedimentary pore water, providing sufficient substrate for N-related bacteria in the sediment under cold temperature conditions. Temperature controls the vertical distribution of DIN by affecting its migratory diffusion and transformation at the sediment-water interface. These findings are valuable for understanding the impact of climate change on the distribution of N in inland shallow lakes,especially in high latitude shallow lakes subjected to large seasonal temperature differences throughout the year.

关键词： Shallow lake Temperature Dissolved inorganic nitrogen Vertical distribution Diffusion flux

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On Ekeland's Variational Principle for Set-Valued Mappings

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Acta Mathematicae Applicatae Sinica 2007年第1期23卷 141-148页

作者： Sheng-jie Li wen-yan Zhang College of Mathematics and Science Chongqing University Chongqing 400044 China

In this paper, we derive a general vector Ekeland variational principle for set-valued mappings, which has a dosed relation to εk^0 -efficient points of set-valued optimization problems. The main result presented in ... 详细信息

关键词： Vector Ekeland variational principle nonlinear scalarization function metric space set-valued mapping

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Early acceleration of electrons and protons at the nonrelativistic quasiparallel shocks with different obliquity angles

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Research in Astronomy and Astrophysics 2019年第12期19卷 298-304页

作者： Jun Fang Chun-yan Lu Jing-wen yan Huan Yu Department of Astronomy Key Laboratory of Astroparticle Physics of Yunnan ProvinceYunnan UniversityKunming 650091China Department of Physical Science and Technology Kunming UniversityKunming 650214China

The early acceleration of protons and electrons in the nonrelativistic collisionless shocks with three obliquities are investigated through 1D particle-in-cell simulations. In the simulations, the charged particles possessing a velocity of 0.2c flow towards a reflecting boundary, and the shocks with a sonic Mach number of 13.4 and an Alfven Mach number of 16.5 in the downstream shock frame are *** these quasi-parallel shocks with the obliquity angles θ = 15°, 30° and 45°, some of the protons and the electrons can be injected into the acceleration processes, and their downstream spectra in the momentum space show a power law tail at a time of 1.89 × 10^5ω^-1pe, where ωpe is the electron plasma ***, the charged particles reflected at the shock excite magnetic waves upstream of the shock. The shock drift acceleration is more prominent with a larger obliquity angle for the shocks, but the accelerated particles diffuse parallel to the shock propagation direction more easily to participate in the diffusive shock acceleration. In the early acceleration stage, more energetic protons and electrons appear in the downstream of the shock for θ = 15° compared with the other two obliquities. Moreover, in the upstream region, the spectrum of the accelerated electrons is the hardest for θnB = 45° among the three obliquities, whereas the proton spectra for θnB = 15° and 45° are similar as a result of the competition of the effectiveness of the shock drift acceleration and the diffusive shock acceleration.

关键词： acceleration of particles methods:numerical shock waves

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