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Formation mechanism and control of MgO·Al_2O_3 inclusions in non-oriented silicon steel

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International Journal of Minerals,Metallurgy and Materials 2014年第11期21卷 1068-1076页

作者： Yan-hui Sun Ya-nan Zeng Rui Xu kai-ke cai School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

On the basis of the practical production of non-oriented silicon steel, the formation of Mg O·Al2O3 inclusions was analyzed in the process of ＂basic oxygen furnace（BOF） → RH → compact strip production（CSP）＂. The thermodynamic and kinetic conditions of the formation of Mg O·Al2O3 inclusions were discussed, and the behavior of slag entrapment in molten steel during RH refining was simulated by computational fluid dynamics（CFD） software. The results showed that the Mg O/Al2O3 mass ratio was in the range from 0.005 to 0.017 and that Mg O·Al2O3 inclusions were not observed before the RH refining process. In contrast, the Mg O/Al2O3 mass ratio was in the range from 0.30 to 0.50, and the percentage of Mg O·Al2O3 spinel inclusions reached 58.4% of the total inclusions after the RH refining process. The compositions of the slag were similar to those of the inclusions; furthermore, the critical velocity of slag entrapment was calculated to be 0.45 m·s^-1 at an argon flow rate of 698 L·min^-1, as simulated using CFD software. When the test steel was in equilibrium with the slag, [Mg] was 0.00024wt%–0.00028wt% and [Al]s was 0.31wt%–0.37wt%; these concentrations were theoretically calculated to fall within the Mg O·Al2O3formation zone, thereby leading to the formation of Mg O·Al2O3 inclusions in the steel. Thus, the formation of Mg O·Al2O3 inclusions would be inhibited by reducing the quantity of slag entrapment, controlling the roughing slag during casting, and controlling the composition of the slag and the Mg O content in the ladle refractory.

关键词： silicon steel steelmaking inclusions deoxidation slag entrapment thermodynamics kinetics

Longitudinal surface cracks of thin slabs

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International Journal of Minerals,Metallurgy and Materials 2010年第2期17卷 159-166页

作者： Yan-hui Sun You-jin Ni Hai-tao Wang Zhong-bo Xu kai-ke cai School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China

Based on the production practice of medium carbon thin slabs in the CSP plant,the reasons and influencing factors for the formation of longitudinal cracks were investigated,and some industrial measures were taken to eliminate the *** results show that the efficient solutions to reduce longitudinal cracks are improving the performance of the mold powder,stabilizing the mold heat flux,and maintaining a proper taper of the mold during *** pouring temperature and secondary cooling also play important roles in preventing longitudinal surface cracks.

关键词： CSP thin slab medium carbon steel surface cracks

Statistical Research on Megahertz-peaked Spectra Pulsars

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Research in Astronomy and Astrophysics 2025年第1期25卷 116-134页

作者： Hong-Bing cai Li Chen Shi-Dang Li kai Wang Hang Liu JSNU SPBPU Institute of Engineering & SINO RUSSIAN Institute Jiangsu Normal University School of Physics and Electronic Engineering Jiangsu Normal University

Megahertz-peaked spectra(MPS) pulsars are referred as cases whose radio spectra turn over around 100 MHz. We identified 53 MPS pulsars based on the spectral data from the literature, and statistically analyzed the spatial location distribution, the magnetic field-period distribution, peak frequencies, spectral indices, and dispersion measures of these MPS pulsars. We found that there is a strong positive correlation between the dispersion measures and the peak frequencies of MPS pulsars, and negative correlations of the dispersion measures with spectral indices and the ages are also found. Such correlations suggest that the interstellar medium is an important factor that affects observational properties of MPS pulsars.

关键词： (stars:) pulsars: general ISM: general radio continuum: general

Some fundamental issues in buoyancy-driven flows with implications for geophysical and astrophysical systems

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Acta Mechanica Sinica 2025年第1期41卷 1-21页

作者： ke-Qing Xia kai Leong Chong Guang-Yu Ding Lu Zhang Center for Complex Flows and Soft Matter Research Southern University of Science and TechnologyShenzhen 518055China Department of Mechanics and Aerospace Engineering Southern University of Science and TechnologyShenzhen 518055China Shanghai key Laboratory of Mechanics in Energy Engineering Shanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200072China

Buoyancy-driven flows are prevalent in a wide range of geophysical and astrophysical systems. In this review, we focus on threepivotal effects that significantly influence the dynamics and transport properties of buoyancy-driven flows and may have impli-cations for natural systems. These effects pertain to the role of boundary conditions, the impact of rotation, and the effect offinite size. Boundary conditions represent how the fluid flow interacts with different kinds of surfaces. Rotation, as the Earth’srotation in geophysical systems or the whirling of astrophysical systems, introduces Coriolis and centrifugal forces, leading tothe profound vortical structure and distinct transport property. Finite size, representing geometrical constraints, influences thebehavior of buoyancy-driven flows across varying geometrical settings. This review aims to provide a holistic understanding ofthe intricate interplay of these factors, offering insights into the complex natural phenomena from the perspectives of the threeeffects.

关键词： Buoyancy-driven flows Geophysical turbulence Rayleigh-B´enard convection

A novel method for simultaneous measurement of^(222)Rn and^(220)Rn progeny concentrations measured by an alpha spectrometer

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Nuclear Science and Techniques 2025年第1期36卷 127-139页

作者： Zhong-kai Fan Jia-Le Sun Hao-Xuan Li Xiang-Ming cai Hui Yang Shou-Kang Qiu Yan-Liang Tan Jian Shan School of Nuclear Science and Technology University of South ChinaHengyang 421001China College of Physics and Electronic Engineering Hengyang Normal UniversityHengyang 421008China

The accumulation of^(222)Rn and^(220)Rn progeny in poorly ventilated environments poses the risk of natural radiation exposure to the public.A previous study indicated that satisfactory results in determining the^(222)Rn and^(220)Rn progeny concentrations by measuring the total alpha counts at five time intervals within 560 min should be expected only in the case of high progeny concentrations in *** complete the measurement within a relatively short period and adapt it for simultaneous measurements at comparatively lower^(222)Rn and^(220)Rn progeny concentrations,a novel mathematical model was proposed based on the radioactive decay *** model employs a nonlinear fitting method to distinguish nuclides with overlapping spectra by utilizing the alpha particle counts of non-overlapping spectra within consecutive measurement cycles to obtain the concentrations of^(222)Rn and^(220)Rn progeny in *** verification experiments were conducted using an alpha *** experimental results demonstrate that the concentrations of^(222)Rn and^(220)Rn progeny calculated by the new method align more closely with the actual circumstances than those calculated by the total count method,and their relative uncertainties are all within±16%.Furthermore,the measurement time was reduced to 90 min,representing an acceleration of 84%.The improved capability of the new method in distinguishing alpha particles with similar energies emitted from ^(218)Po and^(212)Bi,both approximately 6 MeV,contributed to realizing more accurate *** proposed method has the potential advantage of measuring relatively low concentrations of^(222)Rn and^(220)Rn progeny in air more quickly via air filtration.

关键词： ^(222)Rn ^(220)Rn Progeny concentration Nonlinear fitting method Alpha spectrometer

Processing,microstructure,and mechanical properties of wire arc additively-manufactured AZ91 magnesium alloy using cold arc process

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中国有色金属学报 2025年第1期35卷 91-104页

作者： Bai-hao cai Ji-kang FAN Jie LI Dong-qing YANG Yong PENG ke-hong WANG key Laboratory of Controlled Arc Intelligent Additive Technology Ministry of Industry and Information TechnologyNanjing University of Science and TechnologyNanjing 210094China School of Materials Science and Engineering Nanjing University of Science and TechnologyNanjing 210094China

Thin walls of an AZ91 magnesium alloy with fine equiaxed grains were fabricated via cold arc-based wire arc additive manufacturing(CA-WAAM),and the droplet transfer behaviours,microstructures,and mechanical properties were *** results showed that the cold arc process reduced splashing at the moment of liquid bridge breakage and effectively shortened the droplet transfer *** microstructures of the deposited samples exhibited layered characteristics with alternating distributions of coarse and fine *** layer-by-layer deposition,the β-phase precipitated and grew preferentially along grain boundaries,while the fineη-Al_(8)Mn_(5)phase was dispersed in the α-Mg *** mechanical properties of the CA-WAAM deposited sample showed isotropic *** ultimate tensile strength and elongation in the building direction(BD)were 282.7 MPa and 14.2%,*** microhardness values of the deposited parts were relatively uniform,with an average value of HV 69.6.

关键词： AZ91 magnesium alloy droplet transfer microstructure mechanical properties cold arc process

Retrieval of Ozone Profiles Using a Weighted Multiplicative Algebraic Reconstruction Technique from SCIAMACHY Limb Scattering Observations

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Journal of Earth Science 2025年第1期36卷 314-326页

作者： Fang Zhu Fuqi Si ke Dou kai Zhan Haijin Zhou Yuhan Luo Centre of Environmental Optics Anhui Institute of Optics and Fine MechanicsHefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China School of Physics and Electrical Information Huaibei Normal UniversityHuaibei 235000China

This study describes the use of the weighted multiplicative algebraic reconstruction technique(WMART)to obtain vertical ozone profiles from limb observations performed by the scanning imaging absorption spectrometer for atmospheric chartography(SCIAMACHY).This technique is based on SaskMART(the combination of the multiplicative algebraic reconstruction technique and SaskTRAN radiative transfer model),which was originally developed for optical spectrometer and infrared imaging system(OSIRIS)*** of the objectives of this study was to obtain consistent ozone profiles from the two *** this study,the WMART algorithm is combined with a radiative transfer model(SCIATRAN),as well as a set of measurement vectors comprising five Hartley pairing vectors(HPVs)and one Chappuis triplet vector(CTV),to retrieve ozone profiles in the altitude range of 10–69 *** that the weighting factors in WMART have a significant effect on the retrievals,we propose a novel approach to calculate the pair/triplet weighting factors using wavelength weighting *** results of the application of the proposed ozone retrieval scheme are compared with the SCIAMACHY v3.5 ozone product by University of Bremen and validated against profiles derived from other passive satellite observations or measured by *** 18 and 55 km,the retrieved ozone profiles typically agree with data from the SCIAMACHY ozone product within 5%for tropics and middle latitudes,whereas a negative deviation exists between 35 and 50 km for northern high latitudes,with a deviation of less than 10%above 50 *** of the retrieved profiles with microwave limb sounder(MLS)v5.0 indicates that the difference is within±5%between 18 and 55 km,and an agreement within 10%is achieved in other altitudes for tropics and middle *** of the retrieved profiles with OSIRIS v7.1 indicates that the average deviation is within±5%between 20 and 59 km,and difference of approximately 10%is

关键词： retrievals ozone profiles WMART SCIAMACHY limb

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基于多尺度注意力机制的RAW图像重建

北京航空航天大学学报 2025年第1期51卷 257-264页

作者：张科刘昱胡凯天津大学微电子学院天津300072 天津大学浙江国际创新设计与智造研究院绍兴312000

针对传统图像信号处理(ISP)算法繁琐的问题,基于可取代ISP算法的PyNET网络模型,提出一种端到端的RAW图像重建方法Py-CBAM。通过引入高效的注意力机制,并利用该机制对原有网络的多层级多尺度结构进行重设计,实现不同尺度特征的自适应加权... 详细信息

针对传统图像信号处理(ISP)算法繁琐的问题,基于可取代ISP算法的PyNET网络模型,提出一种端到端的RAW图像重建方法Py-CBAM。通过引入高效的注意力机制,并利用该机制对原有网络的多层级多尺度结构进行重设计,实现不同尺度特征的自适应加权,以较大程度提升图像重建的性能。实验结果表明,所提方法在公开的ZRR数据集上获得的峰值信噪比(PSNR)与PyNET方法相比提升了0.37 dB,结构相似度(SSIM)提升了0.0018。将ZRR数据集和新构建的NRR数据集联合对Py-CBAM重新训练后,PSNR和SSIM分别达到25.73 dB和0.9654。视觉效果上,所提方法解决了RAW图像重建时的噪声高与色彩失真、畸变等问题,增强模型在多场景不同光照环境条件下的重建能力;重建结果较为真实,视觉质量最优,在图像过曝和过暗区域视觉提升效果较为明显。

关键词：图像信号处理图像重建增强网络注意力机制深度学习

Association of stent thrombectomy and conventional treatment with neuroprotection, complications, anxiety, and depression in acute ischemic stroke patients

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World Journal of Psychiatry 2025年第1期15卷 72-82页

作者： kai-Jie Yang Jia-Jian Huang cai-Xia Xuan Department of Neurology Qinzhou Second People's HospitalQinzhou 535000Guangxi Zhuang Autonomous RegionChina

BACKGROUND Acute ischemic stroke(AIS)is an abrupt blood flow cessation to a specific brain region within a vascular zone,causing a subsequent decline in neurological *** thrombectomy is a recently established technique for treating *** provides the benefits of being a relatively simple and safe procedure,capable of partially enhancing a patient’s ***,some patients may experience endothelial damage and recurrent thrombosis,with clinical outcomes that are not always ***,the efficacy of this method remains *** To survey the association of stent thrombectomy vs standard treatment with neurological function protection,complications,and short-term prognosis in patients diagnosed with *** This study assigned 90 patients with AIS to the observation and control groups(n=45 patients)from December 2020 to December *** thrombectomy was conducted in the observation group,whereas routine treatment was provided to the control *** study assessed the therapeutic outcomes of two groups,including a comparison of their neurological function,living ability,anxiety and depression status,plaque area,serum inflammatory factors,serum Smur100βprotein,neuron-specific enolase(NSE),homocysteine(Hcy),and vascular endo-thelial ***,the incidence of complications was calculated and analyzed for each *** The total effective rate of treatment was 77.78%and 95.56%in the control and observation groups,*** 8 weeks of treatment,the scores on the National Institutes of Health Stroke Scale,Hamilton Anxiety Scale,and Hamilton Depression Scale decreased remarkably;the Barthel index increased remarkably,with better improvement effects of the scores in the observation group(P<0.05);total cholesterol,triglyceride,C-reactive protein,and plaque area lessened remarkably,with fewer patients in the observation group(P<0.05);S-100βprotein,NSE,and Hcy levels lessened remarkably,with fewer patients in

关键词： Stent thrombectomy Acute ischemic stroke Neurological function Complications Short-term prognosis