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International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 102-110页

作者： Qiang Liu Xiang Li shen du Ming Gao Yanbin Yin Jiongming Zhang State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China

during the continuous casting process of high-Mn high-Al steels,various types of gases such as Ar need to escape through the top of the *** which,the behavior of bubbles traversing the liquid slag serves as a restrictive link,closely associated with viscosity and the thickness of liquid *** contrast to two-dimensional surface observation,three-dimensional(3D)analysis method can offer a more intuitive,accurate,and comprehensive ***,this study employs a 3D X-ray microscope(3D-XRM)to obtained spatial distribution and 3D morphological characteristics of residual bubbles in mold flux under different basicity of liquid slag,different temperatures,and different holding *** results indicate that as basicity of slag increases from 0.52 to 1.03,temperature increases from 1423 to 1573 K,the viscosity of slag decreases,the floating rate of bubbles *** addition,when holding time increases from 10 to 30 s,the bubbles floating distance increases,and the volume fraction and average equivalent sphere diameter of the bubbles solidified in the mold flux gradually *** one word,increasing the basicity,temperature,and holding time leading to an increase in the removal rate of bubbles especially for the *** findings of bubbles escape behavior provide valuable insights into optimizing low basicity mold flux for high-Mn high-Al steels.

关键词： mold flux low basicity bubbles three-dimensional X-ray microscope viscosity

Advances in porous volumetric solar receivers and enhancement of volumetric absorption

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Energy Reviews 2023年第3期2卷 23-44页

作者： Ya-Ling He shen du sheng shen Key Laboratory of Thermo-Fluid Science and Engineering of Ministry of Education School of Energy and Power EngineeringXi'an Jiaotong UniversityXi'anShaanxi710049China Department of Mechanical Engineering Carnegie Mellon UniversityPittsburghPA15213USA

Porous volumetric solar receivers are one type of solar receivers that can volumetrically absorb solar radiation and achieve efficient solar-to-thermal energy *** volumetric solar receivers have been developed since *** this review,we focus on the development progress of the atmospheric and pressurized porous volumetric solar receivers,in which the structural designs,the material selections,the experimental research methods,the comparison of thermal performance,and the transient response characteristic of the receivers were *** the other hand,the theoretical research methods including the direct pore-scale and volume averaging simulations were *** pore-scale reconstruction method and the procedure to investigate the fluid flow and heat transfer processes at the pore-scale were *** the volume averaging method,detailed descriptions for the selection of empirical parameters in the governing equations to be solved were *** research results based on these methods were presented and research limitations were also pointed ***,the methods for the enhancement of volumetric absorption and the improvement of thermal efficiency of the receivers have been comprehensively *** methods including geometrical parameters optimization and spectrally selective absorption were presented in *** review will provide a better understanding of the development and research methods for porous volumetric solar receivers,and inspire future studies for the performance improvement of the receivers.

关键词： Porous media Volumetric solar receiver Experiment progress Direct pore-scale simulation Volume averaging simulation Volumetric absorption enhancement

Numerical investigation on the flow and thermal behaviors of the volumetric solar receivers with different morphologies

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Science China(Technological Sciences) 2024年第9期67卷 2749-2757页

作者： du shen LI Dong LI MengJie HE YaLing National Innovation Platform(Center)for Industry-Education Integration of Energy Storage Technology Key Laboratory of Thermo-Fluid Science and Engineering of Ministry of EducationXi’an Jiaotong UniversityXi’an 710049China

Morphologies of the porous materials influence the processes of solar radiation transport, flow, and thermal behaviors within volumetric solar receivers. A comprehensive comparative study is conducted by applying pore scale numerical simulations on volumetric solar receivers featuring various morphologies, including Kelvin, Weaire-Phelan, and foam configurations. The idealized unit cell and X-ray computed tomography scan approaches are employed to reconstruct pore scale porous *** Carlo ray tracing and pore scale numerical simulations are implemented to elucidate the radiative, flow, and thermal behaviors of distinct receivers exposed to varying thermal boundary conditions and real irradiation situations. The findings demonstrate that the foam structure exhibits greater solar radiation absorptivity, while Kelvin and Weaire-Phelan structures enhance the penetration depth under non-perpendicular solar irradiation. In comparison with Kelvin and Weaire-Phelan configurations, the foam structure presents efficient convective heat transfer, with the Weaire-Phelan structure showing pronounced thermal non-equilibrium phenomena. The variance in convective heat transfer coefficient between Kelvin and Weaire-Phelan configurations is approximately 8.4%. The foam structure exhibits higher thermal efficiency and flow resistance under nonperpendicular irradiation compared to Kelvin and Weaire-Phelan structures, attributed to its smaller pore size and intricate flow channels. An increase of 1.3% in thermal efficiency is observed with a substantial rise in pressure drop of 32.2%.

关键词： volumetric solar receiver porous morphology pore scale method solar radiation absorption thermal performance flow resistance

Numerical study on the effective thermal conductivity and thermal tortuosity of porous media with different morphologies

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Science China(Technological Sciences) 2024年第6期67卷 1685-1694页

作者： du shen LI Dong LI Meng-Jie HE Ya-Ling Key Laboratory of Thermo-Fluid Science and Engineering of Ministry of Education School of Energy and Power EngineeringXi’an Jiaotong UniversityXi’an710049China

Effective thermal conductivity and thermal tortuosity are crucial parameters for evaluating the effectiveness of heat conduction within porous *** direct pore-scale numerical simulation method is applied to investigate the heat conduction processes inside porous structures with different *** thermal conduction performances of idealized porous structures are directly compared with real foams across a wide range of *** foam structures are reconstructed using X-ray computed tomography and image processing techniques,while Kelvin and Weaire-Phelan structures are generated through periodic unit cell *** detailed temperature fields inside the porous structures are determined by solving the heat conduction equation at the pore *** results present that the equivalent thermal conductivity of Kelvin and Weaire-Phelan structures is similar to and greater than that of the real foam structure with the same strut *** thermal tortuosity of real foam structure is relatively larger and the heat conduction path becomes straighter by adopting the anisotropic *** thermal tortuosity of the fluid channels for Kelvin,Weaire-Phelan,and real foam structures is close to *** thermal conductivity of porous structures with heat transfer fluid increases as the thermal conductivity ratio of fluid to solid becomes larger.A small porosity of porous media leads to a larger equivalent thermal conductivity due to the dominant contribution of porous skeleton in the heat conduction *** derived from parallel and series models,as well as the Maxwell-Eucken models,provide decent predictions of effective thermal conductivity,with an average error of less than 8%in the entire range of thermal conductivity ratio.

关键词： volumetric solar receiver porous morphology direct pore-scale simulation equivalent thermal conductivity thermal tortuosity empirical correlation

Comparison of Direct Pore-Scale and Volume-Averaging Methods for the Performance Evaluation of Porous Volumetric Solar Receiver

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Journal of Thermal Science 2024年第5期33卷 1607-1617页

作者： du shen HE Yaling LI Dong LIU Zhanbin LI Mengjie National Innovation Platform(Center)for Industry-Education Integration of Energy Storage Technology Key Laboratory of Thermo-Fluid Science and Engineering of Ministry of EducationXi’an Jiaotong UniversityXi’an710049China

Direct pore-scale and volume-averaging numerical simulations are two methods for investigating the performance of porous volumetric solar *** clarify the difference in the prediction of heat transfer processes,a direct comparison between these two methods was conducted at both steady state and transient *** numerical models were established based on X-ray computed tomography scans and a local thermal non-equilibrium model,*** empirical parameters,which are indispensable to the volume-averaging simulation,were determined by Monte Carlo ray tracing and direct pore-scale numerical *** predicted outlet air temperature of the receiver by the volume-averaging simulation method corresponded satisfactorily to that in the direct pore-scale *** largest discrepancies were observed when the receiver's working temperature was elevated,with differences of 5.5%and 3.68%for the steady state and transient state simulations,***,the volume-averaging method is incapable of capturing the local temperature information of the air and porous *** underestimates the inlet temperature of the receiver,leading to an overestimation of the receiver's thermal efficiency,with the largest difference being 6.51%.The comparison results show that the volume-averaging model is a good approximation to the pore-scale model when the empirical parameters are carefully selected.

关键词： porous media volumetric solar receiver pore-scale method volume-averaging method thermal performance

Experimental and numerical analysis of the hydraulic and thermal performances of the gradually-varied porous volumetric solar receiver

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Science China(Technological Sciences) 2020年第7期63卷 1224-1234页

作者： du shen LI ZengYao HE YaLing LI Dong XIE XiangQian GAO Yang Key Laboratory of Thermo-Fluid Science and Engineering of Ministry of Education School of Energy and Power EngineeringXi'an Jiaotong UniversityXi'an 710049China Science and Technology on Space Physics Laboratory China Academy of Launch Vehicle TechnologyBeijing 100076China

A gradually-varied porous structure is designed to increase the thermal performance of the porous volumetric solar *** on the replica method and multilayer recoating technique, the silicon carbide porous ceramic with linear-changed geometrical parameters is fabricated. The performances of the uniform and gradually-varied porous volumetric solar receivers are studied by both experiment and numerical simulation. An optimization method combining genetic algorithm and computational fluid dynamics analysis is applied to determine the optimum porosity distribution. The results present that porous volumetric solar receiver with linear-changed geometrical parameters exhibits better thermal performance than the uniform porous volumetric solar receivers, especially when the thickness of the receiver is small. Larger porosity in the front is beneficial for increasing the solar radiation penetration depth, which limits the reflectance and thermal radiative losses. Smaller porosity in the rear traps more solar radiation and increases the convective heat transfer. When the receiver’s thickness is larger, the performance of the gradually-varied volumetric solar receiver is nearly identical to that of the uniform receiver with largest porosity. The double-layer configuration is found to be the optimized structure of the gradually-varied porous volumetric solar receiver. The thermal efficiency could be further improved using genetic algorithm with an 11 K increase of the outlet temperature.

关键词： gradually-varied porous volumetric solar receiver replica method local thermal non-equilibrium heat transfer analysis optimization design

Perivascular epithelioid cell tumors of the liver misdiagnosed as hepatocellular carcinoma:Three case reports

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World Journal of Clinical Cases 2023年第2期11卷 426-433页

作者： Yan-Qi Kou Yu-Ping Yang Wei-Xiang Ye Wei-Nan Yuan shen-shen du Biao Nie Department of Gastroenterology The First Affiliated Hospital of Jinan UniversityGuangzhou 510630Guangdong ProvinceChina Department of Gastrointestinal Endoscopy The First Affiliated Hospital of Jinan UniversityGuangzhou 510630Guangdong ProvinceChina

BACKGROUND Hepatic perivascular epithelioid cell neoplasms(PEComas)are *** and treatment experience with hepatic PEComa remains *** SUMMARY Three hepatic PEComa cases are reported in this paper:One case of primary malignant hepatic PEComa,one case of benign hepatic PEComa,and one case of hepatic PEComa with an ovarian mature cystic *** preoperative imaging and pathological assessment of intraoperative frozen samples,patients were diagnosed with hepatocellular carcinoma(HCC),while postoperative pathology and immunohistochemistry subsequently revealed hepatic *** with hepatic PEComa which is misdiagnosed as HCC often require a wider surgical *** is easy to mistake them for distant metastases of hepatic PEComa and misdiagnosed as HCC,especially when it’s combined with tumors in other *** patients eventually underwent partial *** 1-4 years of follow-up,none of the patients experienced recurrence or *** A clear preoperative diagnosis of hepatic PEComa can reduce the scope of resection and prevent unnecessary injuries during surgery.

关键词： Perivascular epithelioid cell neoplasms Hepatocellular carcinoma Case report Diagnoses Coexistence

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The Whole Picture

Beijing Review 2021年第11期64卷 28-29页

作者： shen du 不详

Why it is important to improve Hong Kong's electoral systemThe Central Government holds the power and responsibility to lead improvements in Hong Kong Special Administrative Region (HKSAR)'s electoral *** improvement ... 详细信息

关键词： smoothly Whole holds

Comparison of high order aberration after conventional and customized ablation in myopic LASIK in different eyes of the same patient

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2007年第3期8卷 177-180页

作者： du Chi-xin, shen Ye, WANG Yang (Department of Ophthalmology, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, China) Department of Ophthalmology the First Affiliated Hospital School of Medicine Zhejiang University Hangzhou 310003 China. duchixin@***

Purpose: To verify whether there exists any difference in higher order aberrations after undergoing myopic LASIK (laser in situ keratomileusis) with conventional ablation and customized ablation in different eyes of the same patient. Methods: This was a prospective randomized study of 54 myopic eyes (27 patients) that underwent LASIK using the Nidek EC-5000 ex-cimer laser system (Nidek, Gamagori, Japan). Topography-guided customized aspheric treatment zone (CATz) was used in the first eye of the patient (study group) and the other eye of the same patient was operated on with conventional ablation (control group). Higher order aberrations [root-mean-square (RMS) in the 5-mm zone] of both groups were observed with the Nidek OPD-Scan aberrometer before and 3 months after LASIK. Preoperative mean refractive error was similar between two eyes of the same patient (t=?0.577, P>0.05). Results: Preoperatively, higher order aberrations (RMS in the 5-mm zone) in the CATz ablation and conventional groups were (0.3600±0.0341) μm and (0.2680±0.1421) μm, respectively. This difference was not statistically significant (t=1.292, P>0.05). Three months after LASIK, higher order aberrations (RMS in 5-mm zone) in the CATz ablation and conventional groups were (0.3627±0.1510) μm and (0.3991±0.1582) μm, respectively. No statistically significant difference was noted between pre- and postoperative higher order aberrations in the CATz group (t=?0.047, P>0.05). However, a statistically significant increase in higher order aberrations was observed after conventional ablation (t=?5.261, P<0.05). A statistically sig-nificant difference was noted in the increase of higher order aberrations after LASIK between groups (t=?2.050, P=0.045). Con-clusion: LASIK with conventional ablation and topography-guided CATz ablation resulted in the same BSCVA (best specta-cle-corrected visual acuity) 3 month after LASIK. Higher order aberrations were increased, but the increase of higher order ab-errations afte

关键词： Myopic LASIK (laser in situ keratomileusis) Higher order aberrations Customized ablation

TPD STUDY OF STEAM ADSORPTION ON Ni-RE CATALSTS

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Journal of Energy Chemistry 1992年第4期 352-362页

作者： SONG Ruo-Jun ZHANG Liang-Qu GUO shen-du Chengdu Institute of Organic Chemistry,Academia Sinica Chengdu,Sichuan 610015

Adsorbability to steam of nickel catalysts unpromoted and promot-ed with rare earth for hydrocarbon steam reforming has been comparativelyinvestigated using TPD *** results showed that the adsorptive ca-pacity for steam of promoted Ni catalyst was mainly attributed to the rareearth additive and the amounts of adsorbed steam on reduction state catalystswere 1—1.4 times more than those on oxidation state *** adsorp-tive capacity for steam depended on not only the impregnation mode but alsothe contents of rare *** high contents of rare earth,there were threedifferent adsorption sites on the surface of *** when less than1.3%,the effect on adsorbability to steam became *** promotedNi-catalyst exhibited good coking-resistance and *** mightbe attributed to its great capacity of adsorption to steam.

关键词： TPD STUDY OF STEAM ADSORPTION ON Ni-RE CATALSTS ARN RE mode ANR than Ni