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Building Simulation 2024年第4期17卷 525-542页

作者： Fusuo Xu Dongdong Tian zhi gao Jianshun Jensen Zhang Department of Mechanical and Aerospace Engineering Syracuse UniversitySyracuseNY13210USA School of Architecture and Urban Planning Nanjing University22 Hankou RoadNanjingJiangsu Province210093China

Building surface cool materials are novel materials that can reduce urban heat island intensity and decrease building energy consumption.This study investigated the impact of radiative properties of materials,façade orientation,and morphological parameters on energy consumption in six typical residential neighborhoods in Nanjing,China.The neighborhood energy consumption of 16 application schemes considering the façade orientation factor is compared to determine the best energy-saving scheme.Seasonal and annual energy-saving rates,savings in electricity costs,and the price ceiling for materials per unit area are analyzed.The results show that for low-rise buildings,using cool materials only on the roof can reduce the annual energy consumption by 1%.When cool or super cool materials are also used on the building façade,the annual energy saving rate can be up to 3.4%and 4.3%,respectively.Using cool materials on the south façade of buildings is not recommended due to significant heat loss in winter.Considering savings in electricity costs and the price ceiling for materials per unit area,the price of cool and super cool materials should be less than 3.0 and 3.7 RMB/m2,respectively,assuming a lifespan of eight years in Nanjing.

关键词： cool materials building energy saving neighborhood morphology façade orientation

Influence of friction-lubrication characteristics varying with rolling speed on instability of chatter and slip in cold tandem rolling process

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Journal of Iron and Steel Research(International) 2024年第4期31卷 894-908页

作者： Yan-li Xin zhi-ying gao Bo Tian Qing-dong Zhang School of Mechanical Engineering University of Science and Technology BeijingBeijing 100083China

In the high-speed cold tandem rolling process of thin plate,chatter or slip instability gives rise to the deterioration of equipment and product quality.Macroscopic instability behavior is closely related to interfacial friction-lubrication con-dition which is generally characterized by the friction coefficient.However,with higher and higher speed requirements,the commonly used model of friction coefficient is no longer applicable and accurate.A novel approach is suggested to calculate the speed-dependent friction coefficient,in which the viscosity-pressure-temperature effects of the lubricant,surface roughness states of work rolls and rolled piece are comprehensively involved and the mixed flm lubrication theory is applied.Subsequently,the influences of friction coefficient on the instability of slip and chatter are investigated for a five-stand cold tandem rolling mill.On one side,the critical friction coefficient for each stand is determined by calculating the corresponding slip factor;on the other hand,the friction coefficient varying with rolling speed is combined with the model of theoretical critical rolling speed presented under constant friction coefficient,so that the speed threshold is determined.Furthermore,the stable and unstable regions corresponding to the rear three stands are individually discussed,and the technical strategies are proposed to suppress both slip and chatter frequently occurring in the actual rolling process.

关键词： Cold tandem rolling:Oil film thickness Speed-dependent friction coefficient-Slip:Chatter

Thiazoloisoindigo-based Polymer Semiconductors: Synthesis,Structure-Property Relationship, Charge Carrier Polarity, and Field-Effect Transistor Performance

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Chinese Journal of Polymer Science 2024年第1期42卷 24-31,I0006页

作者： Bo-Wen Li Miao Xiong Mei-Hua Liu zhi-gao Li Long Sang Zi-Han Xiong Biao Xiao Jian Pei Xiao-Bo Wan Key Laboratory of Optoelectronic Chemical Materials and Devices Ministry of EducationSchoolofOptoelectronic Materials&TechnologyJianghan UniversityWuhan430056China Bejing National Laboratoryfor Molecular Sciences the Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of EducationCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

Developing new polymeric semiconductors with excellent device performance is essential for organic electronics. Herein, we synthesized two new thiazoloisoindigo(Tz II)-based polymers, namely, P(Tz II-d Th-d Th) and P(Tz II-d Th-d Tz), by copolymerizing thiophene-flanked Tz II with bithiophene and bithiazole, respectively. Owing to the more electron-deficient nature of bithiazole than bithiophene, P(Tz II-d Th-d Tz)possesses deeper LUMO/HOMO levels of-3.45/-5.47 e V than P(Tz II-d Th-d Th)(-3.34/-5.32 e V). The organic field-effect transistor(OFET) devices based on P(Tz II-d Th-d Th) exhibited p-type behaviors with an average hole mobility value as high as 1.43 cm^(2)·V^(-1)·s^(-1), while P(Tz II-d Th-d Tz)showed typical ambipolar characteristics with average hole and electron mobilities of 0.38 and 0.56 cm^(2)·V^(-1)·s^(-1). In addition, we compared the performances of both polymers with other Tz II-based polymers reported in our previous work, and showed that the charge carrier polarity can be manipulated by adjusting the number of the thiophene units between the acceptor unit. As the increase of the number of thiophene rings,charge carrier polarity shifts from electron-dominated ambipolar transport to hole-dominated ambipolar transport and then to unipolar hole transport in OFETs, which provides an effective molecular design strategy for further optimization of polymer OFET performance.

关键词： Field-effect transistor Charge carrier polarity Thiazoloisoindigo

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Effect of aging treatment on the precipitation transformation and age hardening of Mg-Gd-Y-Zn-Zr alloy

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Journal of Magnesium and Alloys 2023年第12期11卷 4628-4643页

作者： Mu Meng Honglei Zhang zhi gao Genxing Lei Jianmin Yu College of Materials Science and Engineering North University of ChinaXueyuan Road 3Taiyuan 030051China Beijing North Vehicle Group Corporation ZhuJiaFen 5th LiBeijing 100072China

In this study, the precipitation transformation and age hardening of solution-treated Mg-9Gd-4Y-2Zn-0.5Zr(wt.%) alloy were investigated at different aging treatment parameters. The precipitation sequences of the alloy aged at 200℃, 250℃ and 300℃ are β’’(DO19) → β’(BCO) → β(FCC), β’’(DO19) → β’(BCO) → β_(1)(FCC) → β(FCC) and β(FCC), respectively. The streaks sequences of the alloy aged at 200℃, 250℃ and 300℃ are SF, SF → 14H-LPSO and SF → 14H-LPSO, respectively. For the alloy aged at 200℃ and 250℃, the increase in hardness with increasing aging time is contributed from the increase in precipitate volume fraction and the transformation from β’’ to β’ phase with basal → prismatic and spherical → spindle-like precipitate changes. The decrease in hardness after the peak-aging stage is attributed to the appearance of micro-sized β precipitates. Because of the smaller size of precipitates and the triangular arrangement of β’ precipitate, the hardness of the alloy aged at 200℃ is higher than that aged at 250℃. For the alloy aged at 300℃, the appearance of only micro-sized β precipitate and its coarsening with increasing aging time leads to the lowest hardness and an overall decrease in hardness with the aging time.

关键词： Mg-Gd-Y-Zn-Zr alloy Aging treatment Precipitation transformation Age hardening

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Severe pediatric COVID‑19:a review from the clinical and immunopathophysiological perspectives

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World Journal of Pediatrics 2024年第4期20卷 307-324页

作者： Yi‑Kan Sun Can Wang Pei‑Quan Lin Lei Hu Jing Ye zhi‑Gang gao Ru Lin Hao‑Min Li Qiang Shu Li‑Su Huang Lin‑Hua Tan Children's Hospital Zhejiang University School f MedicineHangzhou 310052China The Second Affiliated Hospital Zhejiang University School of MedicineHangzhou 310030China Surgical Intensive Care Unit Children’s HospitalZhejiang University School of MedicineHangzhou 310052China Department of General Surgery Children’s HospitalZhejiang University School of MedicineHangzhou 310052China Department of Cardiopulmonary and Extracorporeal Life Support Children’s HospitalZhejiang University School of MedicineHangzhou 310052China Clinical Data Center Children’s HospitalZhejiang University School of MedicineHangzhou 310052China Department of Cardiac Surgery Children’s HospitalZhejiang University School of MedicineHangzhou 310052China National Clinical Research Center for Child Health Children’s HospitalZhejiang University School of MedicineHangzhou 310052China Department of Infectious Diseases Children’s HospitalZhejiang University School of MedicineHangzhou 310052China

Background Coronavirus disease 2019(COVID-19)tends to have mild presentations in children.However,severe and critical cases do arise in the pediatric population with debilitating systemic impacts and can be fatal at times,meriting further attention from clinicians.Meanwhile,the intricate interactions between the pathogen virulence factors and host defense mechanisms are believed to play indispensable roles in severe COVID-19 pathophysiology but remain incompletely understood.Data sources A comprehensive literature review was conducted for pertinent publications by reviewers independently using the PubMed,Embase,and Wanfang databases.Searched keywords included“COVID-19 in children”,“severe pediatric COVID-19”,and“critical illness in children with COVID-19”.Results Risks of developing severe COVID-19 in children escalate with increasing numbers of co-morbidities and an unvaccinated status.Acute respiratory distress stress and necrotizing pneumonia are prominent pulmonary manifestations,while various forms of cardiovascular and neurological involvement may also be seen.Multiple immunological processes are implicated in the host response to COVID-19 including the type I interferon and inflammasome pathways,whose dysregulation in severe and critical diseases translates into adverse clinical manifestations.Multisystem inflammatory syndrome in children(MIS-C),a potentially life-threatening immune-mediated condition chronologically associated with COVID-19 exposure,denotes another scientific and clinical conundrum that exemplifies the complexity of pediatric immunity.Despite the considerable dissimilarities between the pediatric and adult immune systems,clinical trials dedicated to children are lacking and current management recommendations are largely adapted from adult guidelines.Conclusions Severe pediatric COVID-19 can affect multiple organ systems.The dysregulated immune pathways in severe COVID-19 shape the disease course,epitomize the vast functional diversity of the pediatric immune system and highlight the immun

关键词： Immunopathophysiology MIS-C Pediatric critical care Severe pediatric COVID-19

Application of CFD plug-ins integrated into urban and building design platforms for performance simulations:A literature review

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Frontiers of Architectural Research 2023年第1期12卷 148-174页

作者： Yongyu Hu Yunlong Peng zhi gao Fusuo Xu School of Architecture and Urban Planning Nanjing UniversityNanjing 210093China

The transformation of urban and building design into green development is conducive to alleviating resource and environmental problems.Building design largely determines pollutant emissions and energy consumption throughout the building life cycle.Full consideration of the impact of urban geometries on the microclimate will help construct livable and healthy cities.Computational fluid dynamics(CFD)simulations significantly improve the efficiency of assessing the microclimate and the performance of design schemes.The integration of CFD into design platforms by plug-ins marks a landmark development for the interaction of computer-aided design(CAD)and CFD,allowing architects to perform CFD simulations in their familiar design environments.This review provides a systematic overview of the classification and comprehensive comparison of CFD plug-ins in Autodesk Revit,Rhinoceros/Grasshopper,and SketchUp.The applications of CFD plug-ins in urban and building design are reviewed according to three types:single-objective,multi-objective,and coupling simulations.Two primary roles of CFD plug-ins integrated into the design process,including providing various micro-scale numerical simulations and optimizing the original design via feedback results,are analyzed.The issues of mesh generation,boundary conditions,turbulence models,and simulation accuracy during CFD plug-in applications are discussed.Finally,the limitations and future possibilities of CFD plug-ins are proposed.

关键词： Urban design Building design Computational fluid dynamics(CFD) Performance simulation Integration Optimization

Unraveling magnetic properties and martensitic transformation in Mn-rich Ni-Mn-Sn alloys:first-principles calculations and experiments

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Rare Metals 2024年第4期43卷 1769-1785页

作者： Yu Zhang Jing Bai Ke-Liang Guo Jia-Xin Xu Jiang-Long Gu Nicola Morley Qui-zhi gao Yu-Dong Zhang Claude Esling Xiang Zhao Liang Zuo Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education) School of Material Science and EngineeringNortheastern University Key Laboratory of Dielectric and Electrolyte Functional Material Hebei Province School of Resources and Materials Northeastern University at Qinhuangdao Department of Material Science and Engineering University of Sheffield State Key Laboratory of Metastable Materials Science and Technology Yanshan University Laboratoire d'Etude des Microstructures Et de Mecanique des Materiaux University of Lorraine

We have investigated the phase stability,magnetic properties,and martensitic transformation thermodynamics/kinetics of the Ni24-xMn18+x+ySn6-y（x,y=0,1,2） system by combining the first-principles calculations and experiments.The calculation results show that the optimized lattice parameters are consistent with the experimental data.Respectively,we obtain the relation equation for the austenite formation energy(Eform-A) and Mn content(XMn):Eform-A=507.358XMn-274.126,as well as for the six-layer modulated（6M） martensite formation energy(Eform-6M) and Ni content(XNi):Eform-6M=-728.484XNi+264.374.The ternary phase diagram of the total magnetic moment was established.The excess Mn will reduce the total magnetic moment of 6M（Mag6M） and non-modulated（NM）(MagNM) martensites,with the following equations relating the total magnetic moment and Mn content:Mag6M=-15.905XMn+7.902and MagNM=-14.781XMn+7.411,while the effect on austenite is complex.The variation of total magnetic moment is mainly dominated by the Mn atomic magnetic moment.The 3d electrons of MnSn（Mn at Sn sublattice）play an important role in magnetic properties from the perspective of the electronic density of states.Based on the thermodynamics of martensitic transformation,the alloys will likely undergo austenite?6M?NM transformation sequence.Combining the thermodynamic and kinetic results,the martensitic transformation temperature decreases with x increasing and increases with y increasing.These results are expected to provide reference for predicting the phase stability and magnetic properties of NiMn-Sn alloys.

关键词： Ni–Mn–Sn First-principles calculations Martensitic transformation Magnetic property Kinetics

On the effects of urban-like intersections on ventilation and pollutant dispersion

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Building Simulation 2022年第3期15卷 419-433页

作者： Xin Guo Riccardo Buccolieri zhi gao Mingjie Zhang Tong Lyu Liyan Rui Jialei Shen School of Architecture and Urban Planning Nanjing University22 Hankou RoadNanjing 210093Jiangsu ProvinceChina Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali Laboratory of MicrometeorologyUniversity of SalentoS.P.6 Lecce-Monteroni73100LecceItaly Department of Green Building and Low-Carbon Development Shanghai Research Institute of Building Sciences568 Shenfu RoadShanghai201108China Department of Mechanical and Aerospace Engineering Syracuse UniversitySyracuseNY13210USA

Focusing on the effect of street morphology on the ventilation efficiency,this paper presents 3D computational fluid dynamics(CFD)simulations of airflow and pollutant dispersion within urban-like three-way intersections,four-way intersections and roundabouts.The steady-state Reynolds-averaged Navier-Stokes(RANS)k-εturbulence model is adopted and eight directions of the approaching wind are considered.The ventilation efficiency is evaluated using the ventilation indices purging flow rate(PFR)and the net escape velocity(NEV).Results show the sensitivity of the ventilation efficiency to the type of intersection,to the wind direction and to the number of branches.Specifically,the ventilation efficiency of the investigated three-way intersections is found to be better than that of the other intersections,especially when the angle between the streets is large,while that of roundabouts is also considerable,even with a similar average wind velocity,among the cases evaluated in this paper.Further,the influence of the wind direction for the three-way and four-way intersections is greater than that on roundabouts.Studies on the ventilation efficiency at urban intersections are not common in the literature and this work may help urban planners to better design such hub nodes of urban traffic,where traffic-related pollutants are not easily dispersed,thus avoiding harm to the health of pedestrians and surrounding residents.

关键词： urban-like intersections ventilation efficiency CFD simulations traffic-related pollutants

Constructing dual-functional porphyrin-based thorium metal-organic framework toward photocatalytic uranium(Ⅵ)reduction integrated with organic oxidation

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Science China Chemistry 2022年第8期65卷 1544-1551页

作者： zhi gao Yue Wang Yuzhi Lin zhijian Zheng Yao Liu Qiqi Jing Feng Luo Jiangxi Province Key Laboratory of Synthetic Chemistry East China University of TechnologyNanchang 330013China

The rational fabrication of photocatalysts with dual functions upon visible light, such as photocatalytic radioactive U(Ⅵ)reduction and value-added organic oxidation, is highly desirable but remains huge challenge. Here, we couple the photocatalytic U(Ⅵ) reduction with the oxidative organic synthesis to one system using novel extended π-conjugated framework(Cu@ThTCPP) without the expense of sacrificial reagents. Noticeably, the as-prepared Cu@Th-TCPP linked by tetratopic tetrakis(4-carboxyphenyl)porphyrin(TCPP) ligand and unique Th(μ-O)(HCOO)(HO)secondary building unit(SBU) exhibits significantly enhanced activity when the photocatalytic U(Ⅵ) reduction and thioanisole oxidation were integrated to one system.Further experimental characterizations demonstrate that the highly conjugated framework of Cu@Th-TCPP is good for the charge transfer and separation, while incorporating Cusite further accelerates the charge-carrier dynamics, thus giving rise to the dual-functional property. Apparently, this strategy conforms to atomic economy, opens a new horizon to address radioactive environmental pollution in natural water systems and soils, and simultaneously produces valuable chemicals.

关键词： radioactive U(Ⅵ)reduction oxidative organic synthesis charge separation dual-functional Th-MOF photocatalysis

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MFVNet: a deep adaptive fusion network with multiple field-of-views for remote sensing image semantic segmentation

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Science China(Information Sciences) 2023年第4期66卷 93-106页

作者： Yansheng LI Wei CHEN Xin HUANG zhi gao Siwei LI Tao HE Yongjun ZHANG School of Remote Sensing and Information Engineering Wuhan University

In recent years, the remote sensing image(RSI) semantic segmentation attracts increasing research interest due to its wide application. RSIs are difficult to be processed holistically on current GPU cards on account of their large field-of-views(FOVs). However, the prevailing practices such as downsampling and cropping will inevitably decrease the quality of semantic segmentation. To address this conflict,this paper proposes a new deep adaptive fusion network with multiple FOVs(MFVNet), which is specially designed for RSI semantic segmentation. Different from existing methods, MFVNet takes into consideration the differences among multiple FOVs. By pyramid sampling the RSI, we first obtain images on different scales with multiple FOVs. Images on the high scale with a large FOV can capture larger spatial contexts and complete object contours, while images on the low scale with a small FOV can keep the higher spatial resolution and more detailed information. Then scale-specific models are chosen to make the best predictions for all scales. Next, the output feature maps and score maps are aligned through the scale alignment module to overcome spatial misregistration among scales. Finally, the aligned score maps are fused with the help of adaptive weight maps generated by the adaptive fusion module, producing the fused prediction. The performance of MFVNet surpasses the previous state-of-the-art semantic segmentation models on three typical RSI datasets, demonstrating the effectiveness of the proposed MFVNet.

关键词： semantic segmentation remote sensing image (RSI) field-of-view (FOV) adaptive fusion convolutional neural network