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Conduction-convection coupled heat transfer around a hollow cylinder under different buoyancy forces

Chinese Journal of Aeronautics 2024年第4期37卷 216-228页

作者： Wanyu ZHANG Jingyi WU guang yang Institute of Refrigeration and Cryogenics Shanghai Jiao Tong UniversityShanghai 200240China

In order to clarify the effect of a buoyancy force on conduction–convection coupled heat transfer in a hollow cylinder, the flow and thermal characteristics we.e analyzed using an RNG k-ε turbulence model. The Reynolds number was fixed at 1.014 × 10^(6), and the Rayleigh number varied from 1.122 × 10^(10)to 1.088 × 10^(11). Results have shown that, when considering the effect of an opposed buoyancy force, increasing the Rayleigh number has a positive impact on the rate of change and uniformity of the cylinder temperature. The temperature distributions along the axial and circumferential directions are similar for different Rayleigh numbers, but extreme values *** the axial direction, the maximum temperature is obtained at the interface betwe.n the variable-diameter part and the constant-diameter part. The maximum dimensionless temperature value decreases to 0.12 when the Rayleigh number increases to 1.088 × 10^(11). Along the circumferential direction, the temperature distribution is affected by the buoyancy force, which results in the temperature of the upper part being higher than that of the lowe. part. After nondimensionalization of the temperature and time, a correlation was proposed to illustrate the transient heat transfer process quantitatively. The standard deviation of the maximum relative temperature, representing the temperature uniformity, was also calculated. It was found that the difference in the direction of the buoyancy force made a huge difference. Compared with the opposed buoyancy force, the maximum dimensionless temperature is almost two times higher with an assisted buoyancy force. Similarly, the heat transfer coefficient with an assisted buoyancy force is half of that with an opposed buoyancy force. Overall, an assisted buoyancy force plays a negative role in terms of thermal characteristics. The flow field around the hollow cylinder was also illustrated to reveal the mechanism of the buoyancy force on magnitude and direction aspects

关键词： Buoyancy Conduction-convection heat transfer Transient analysis Hollow cylinder Non-dimensionalization

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B cell development and antibody responses in human immune system mice:current status and future perspective

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Science China(Life Sciences) 2024年第4期67卷 645-652页

作者： Tao Zhang we.tao Liu Yong-guang yang Key Laboratory of Organ Regeneration&Transplantation of the Ministry of Education The First Hospital of Jilin UniversityChangchun 130061China National-Local Joint Engineering Laboratory of Animal Models for Human Diseases Jilin UniversityChangchun 130061China International Center of Future Science Jilin UniversityChangchun 130061China

Humanized immune system(HIS)mice have been developed and used as a small surrogate model to study human immune function under normal or disease *** variations are found betwe.n models,most HIS mice show robust human T cell ***,there has been unsuccessful in constructing HIS mice that produce high-affinity human antibodies,primarily due to defects in terminal B cell differentiation,antibody affinity maturation,and development of primary follicles and germinal *** this review,we.elaborate on the current knowledge about and previous attempts to improve human B cell development in HIS mice,and propose a potential strategy for constructing HIS mice with improved humoral immunity by transplantation of human follicular dendritic cells(FDCs)to facilitate the development of secondary follicles.

关键词： humanized immune system mouse humoral immunity germinal center B cell follicular dendritic cell

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Current status and challenges of pig-to-human organ xenotransplantation

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Science China(Life Sciences) 2024年第4期67卷 829-831页

作者： Minghui Fang Yong-guang yang Zheng Hu Key Laboratory of Organ Regeneration&Transplantation of Ministry of Education and National-Local Joint Engineering Laboratory of Animal Models for Human DiseasesThe First Hospital of Jilin UniversityChangchun 130061China

Organ shortage is a global *** collected by the Global Observatory on Donation and Transplantation reveals that over 150,000 solid organ transplants are conducted globally each year,a 52%increase from 2010(http://***/... 详细信息

关键词： globally global shortage

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Self-cleaning effect and secondary swirling clean gas for suppressing particle deposition on vortex finder of gas cyclones

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Particuology 2024年第7期90卷 72-87页

作者： Zhanpeng Sun Huandi yang Kaixuan Zhang Zhiyuan Wang Zhenyuan Hong guang yang School of Mechanical Engineering Hebei University of Science&TechnologyShijiazhuang050018China

In order to suppressing the particle deposition on vortex finder,a series of gas cyclones with the secondary swirling clean gas we.e developed inspired by the gas purge *** of the width and extension length of the flow channel as we.l as the secondary inlet velocity and running time on the particle deposition pattern,the deposited particle mass and the cyclones'performance we.e experimentally investigated,*** results show that the ultrafine particles(Stokes number Stk<0.0358)are mainly loose deposited on the walls under the secondary *** to the conventional cyclone with single tangential inlet,the total deposited particle mass of the improved cyclone has a maximum reduction more than 60%,and the collecting efficiency is increased up to 97.5%under the basically same pressure *** corresponding no-deposition area is increased by about 13%,and remains constant in spite of extending the running ***,an interesting phenomenon named"self-cleaning effect"of the vortex finder was captured for the gas cyclones,and mechanism of the secondary clean gas on the particle deposition is preliminarily *** results can deepen the understanding of the particle deposition on the vortex finder and guide the design of the anti-coking gas cyclones.

关键词： Cyclones Vortex finder Particle deposition Gas purge effect Self-cleaning effect

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Micro/nanosystems for controllable drug delivery to the brain

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The Innovation 2024年第1期5卷 139-157页

作者： Mingzhen Tian Zhichao Ma guang-Zhong yang Institute of Medical Robotics School of Biomedical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Drug delivery to the brain is crucial in the treatment for central nervous system *** significant progress has been made in recent years,there are still major challenges in achieving controllable drug delivery to the *** clinical needs arise from various factors,including controlled drug transport,handling large drug doses,methods for crossing biological barriers,the use of imaging guidance,and effective models for analyzing drug *** advances in micro/nanosystems have shown promise in addressing some of these *** include the utilization of microfluidic platforms to test and validate the drug delivery process in a controlled and biomimetic setting,the development of novel micro/nanocarriers for large drug loads across the blood-brain barrier,and the implementation of micro-intervention systems for delivering drugs through intraparenchymal or peripheral *** this article,we.present a review of the latest developments in micro/nanosystems for controllable drug delivery to the *** also delve into the relevant diseases,biological barriers,and conventional *** addition,we.discuss future prospects and the development of emerging robotic micro/nanosystems equipped with directed transportation,real-time image guidance,and closed-loop control.

关键词： equipped doses barriers

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Online task planning method of anti-ship missile based on rolling optimization

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Journal of Systems Engineering and Electronics 2024年第3期35卷 720-731页

作者： LU Faxing DAI Qiuyang yang guang JIA Zhengrong College of we.ponry Engineering Naval University of EngineeringWuhan 430033China

Based on the wave attack task planning method in static complex environment and the rolling optimization framework, an online task planning method in dynamic complex environment based on rolling optimization is proposed. In the process of online task planning in dynamic complex environment,online task planning is based on event triggering including target information update event, new target addition event, target failure event, we.pon failure event, etc., and the methods include defense area reanalysis, parameter space update, and mission re-planning. Simulation is conducted for different events and the result shows that the index value of the attack scenario after re-planning is better than that before re-planning and according to the probability distribution of statistical simulation method, the index value distribution after re-planning is obviously in the region of high index value, and the index value gap before and after re-planning is related to the degree of posture change.

关键词： target allocation of anti-ship missile defense area rolling optimization task re-planning

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Extreme value theory applied to the auroral electrojet indices

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Earth and Planetary Physics 2024年第2期8卷 375-381页

作者： Si Chen Hong Yuan Yong we. guang yang FengZheng Yu Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

The study of extreme we.ther and space events has gained paramount importance in modern society owing to rapid advances in high *** and describing exceptional occurrences plays a crucial role in making decisive assessments of their potential impact on technical,economic,and social aspects in various *** research focuses on analyzing the hourly values of the auroral electrojet(AE)geomagnetic index from 1957 to 2019 by using the peak over threshold method in extreme value *** fitting the generalized Pareto distribution to extreme AE values,shape parameter indices we.e derived,revealing negative values that establish an upper bound for this time ***,it became evident that the AE values had reached a plateau,suggesting that extreme events exceeding the established upper limit are *** a result,although the need for diligent precautions to mitigate the consequences of such extreme events persists,surpassing the upper limit of AE values becomes increasingly *** is also possible to observe an aurora in the middle-and low-latitude regions during the maximum period of the AE index.

关键词： auroral electrojet indices extreme value theory extreme events

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Highly Improved Creep Resistance in Polypropylene Through Thermally Reduced Graphene Oxide and Its Creep Lifetime Prediction

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Chinese Journal of Polymer Science 2024年第2期42卷 256-266,I0010页

作者： Can-Can Zhang Jun-Long yang Ya-Jiang Huang guang-Xian Li College of Polymer Science and Engineering State Key Laboratory of Polymer Materials Engineering of ChinaSichuan UniversityChengdu610065China

Polypropylene(PP) exhibits suboptimal creep resistance due to the presence of methyl groups on its main chain, leading to irregular chain segment distribution, diminished inter-chain interaction, and crystallinity. This structural feature causes chain slippage in PP under stress,significantly constraining its service lifetime. In this study, thermally reduced graphene oxide(TrGO) nanosheets we.e incorporated into the PP matrix, yielding a nanocomposite with exceptional creep resistance performance. Results demonstrated that at a stress of 25 MPa, a 2.0 wt% TrGO content could enhance the creep failure lifetime of PP by 21.5 times compared to neat PP. Rheology, transmission electron microscopy(TEM),and scanning electron microscopy(SEM) characterization techniques we.e employed to analyze the mechanism of TrGO's influence on PP's creep behavior. It was observed that when TrGO content exceeded 1.0 wt%, an effective particle network structure formed within the PP matrix. This homogeneously dispersed TrGO-formed particle network structure restricted the migration and rearrangement of PP molecular chains, enabling prolonged stress resistance without structural failure. By combining the time-strain superposition method with the critical failure strain as a criterion, generalized creep compliance curves for PP and its composites we.e established, facilitating the prediction of material creep failure lifetimes, with a strong agreement betwe.n experimental and predicted lifetime values. This research proposes a novel strategy aimed at developing polypropylene materials and products with enhanced long-term stability and durability, thus extending service life, reducing failure risk, and broadening their potential across various application domains.

关键词： Thermally reduced graphene oxide Polypropylene Creep failure and lifetime prediction

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Advances in depressants for flotation separation of Cu–Fe sulfide minerals at low alkalinity:A critical review

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 1-17页

作者： Qicheng Feng we.hang yang Maohan Chang Shuming we. Dianwe. Liu guang Han State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization Faculty of Land Resource EngineeringKunming University of Science and TechnologyKunming 650093China Yunnan Key Laboratory of Green Separation and Enrichment of Strategic Mineral Resources Kunming University of Science and TechnologyKunming 650093China

The flotation separation of Cu–Fe sulfide minerals at low alkalinity can be achieved using selective *** the flotation system of Cu–Fe sulfide minerals,depressants usually preferentially interact with the pyrite surface to render the mineral surface hydrophilic and hinder the adsorption of the *** review summarizes the advances in depressants for the flotation separation of Cu–Fe sulfide minerals at low *** advances include use of inorganic depressants (oxidants and sulfur–oxygen compounds),natural polysaccharides (starch,dextrin,konjac glucomannan,and galactomannan),modified polymers (carboxymethyl cellulose,polyacrylamide,lignosulfonate,and tricarboxylate sodium starch),organic acids (polyglutamic acid,sodium humate,tannic acid,pyrogallic acid,salicylic acid,and lactic acid),sodium dimethyl dithiocarbamate,and *** potential application of specific inorganic and organic depressants in the flotation separation of Cu–Fe sulfide minerals at low alkalinity is *** advances in the use of organic depressants with respect to the flotation separation of Cu–Fe sulfide minerals are comprehensively ***,the depression performances and mechanisms of different types of organic depressants on mineral surfaces are ***,several perspectives on depressants vis-à-vis flotation separation of Cu–Fe sulfide minerals at low alkalinity are proposed.

关键词： Cu–Fe sulfide minerals flotation separation selective depressants depression mechanism

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Effect of MgO-Cr_(2)O_(3) and Mg0-MgAl_(2)0_(4)-based refractories on refractory-steel interface reaction and cleanliness of pipeline steel

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Journal of Iron and Steel Research(International) 2024年第4期31卷 849-860页

作者： guang-mei yang Cheng Yuan Chang Liu Qiang Wang guang-qiang Li Yong-shun Zou Ao Huang 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

The interaction of MgO-MgAl_(2)O_(4)-based and MgO-Cr_(2)O_(3)-based refractories with X70 molten steel was studied by immersion experiments at 1560℃.The effects of immersion time(30 and 60 min)on the contents of total oxygen(TO),Al,Nb,Si,Mn,and Cr as we.l as the composition,number density,and size distribution of inclusions in the molten steel we.e *** influence of the penetration and erosion degree of the molten steel to the refractory on the steel-refractory interface layer was *** results show that,at 1560℃,the MgO-MgAl_(2)O_(4)-based refractory can better control the contents of TO and the composition of molten steel compared with the MgO-Cr_(2)O_(3)-based *** TO content is only 16×10^(-4) wt.%in the molten steel after reacted with the Mg0-MgAl_(2)O_(4)-based refractory at the end point of refining,4 accounting for 11.5%of that reacted with the MgO-Cr_(2)O_(3)-based refractory(139×10^(-4) wt.%).The number density of inclusions is only 14 mm^(-2),and the average size ofinclusions is only 1.31μm,with thelargest proportion of inclusions in 1-2μm(70%).The Al_(2)O_(3)-MnS-CaO complex inclusions in the original steel changed to complex inclusions dominated by Cr-Nb-Mn-S-O and ***_(2)O_(3),corresponding to the MgO-Cr_(2)O_(3)-based and MgO-MgAl_(2)O_(4)-based refractories,*** ***_(2)O_(3) layer was formed at the reaction interface betwe.n MgO-MgAl_(2)O_(4)-based refractory and molten steel,which is helpful to restrict the erosion of refractories and the pollution of molten *** damage mechanism of the MgO-Cr_(2)O_(3)-based refractory is mainly permeation and chemical reaction,while the damage of the MgO-MgAl_(2)O_(4)-based refractory is mainlyscouring erosion.

关键词： MgO-Cr_(2)O_(3)-based refractory MgO-MgAl O_(4)-based refractory Nonmetallic inclusion Erosion interface layer Steel penetration

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