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Turbulent flows over real heterogeneous urban surfaces:Wind tunnel experiments and Reynolds-averaged Navier-Stokes simulations

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Building Simulation 2021年第5期14卷 1345-1358页

作者： wai-chi cheng Chun-Ho Liu Yat-Kiu Ho Ziwei Mo Zhangquan Wu Wenye Li Lilian Y.L.Chan W.K.Kwan Hing Tuen Yau School of Atmospheric Sciences and Guangdong Province Key Laboratory for Climate Change and Natural Disaster StudiesSun Yat-sen UniversityZhuhaiChina Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) ZhuhaiChina Department of Mechanical Engineering The University of Hong KongHong KongChina Information Technology Services The University of Hong KongHong KongChina

Wind tunnel experiment and steady-state Reynolds-averaged Navier-Stokes(RANS)approaches are used to examine the urban boundary layer(UBL)development above Kowloon Peninsula,Hong Kong Special Administrative Region(HKSAR).The detailed urban morphology is resolved by computational fluid dynamics(CFD)and is fabricated by 3D-printing(reduced scale)for wind tunnel *** from the majority existing results based on idealized,homogeneous urban geometries,it was found that the wind and turbulence in the UBL over downtown Kowloon are characterized by the wake behind several high-rise *** particular,local maxima of turbulence kinetic energy(TKE)and shear stress are found at the roof level of those high-rise *** the downstream region where the flows are already adjusted to the urban surfaces,the urban roughness sublayer(URSL)can be further divided into two layers based on the structures of the mixing length/m,effective drag Dx and dispersive *** the lower URSL(z<100 m),lm is rather uniform,and the Reynolds stress and dispersive stress are *** the upper URSL(100 m z s 300 m),on the contrary,lm is peaked at the mid-height and the magnitude of dispersive stress is smaller than that of the Reynolds stress(<30%).The effective drag Dx is negligible in the upper URSL.

关键词： computational fluid dynamics(CFD) real urban morphology urban boundary layer(UBL) urban canopy model(UCM) wind tunnel experiments

Honeycomb-like biochar framework coupled with Fe_(3)O_(4)/FeS nanoparticles as efficient heterogeneous Fenton catalyst for phenol degradation

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Journal of Environmental Sciences 2024年第2期136卷 390-399页

作者： Aihua cheng Yi He Xiaohe Liu chi He Department of Environmental Engineering College of Geology and EnvironmentXi’an University of Science and TechnologyXi’an 710054China State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power EngineeringXi’an Jiaotong UniversityXi’an 710049China National Engineering Laboratory for VOCs Pollution Control Material and Technology University of Chinese Academy of SciencesBeijing 101408China

Achieving an efficient and stable heterogeneous Fenton reaction over a wide pH range is of great significance for wastewater ***,a pollen-derived biochar catalyst with a unique honeycomb-like structure,coupled with the dispersion of magnetic Fe_(3)O_(4)/FeS(Fe/S)nanoparticles,was synthesized by simple impregnation precursor,followed by *** prepared Fe/S-biochar catalyst demonstrated outstanding phenol degradation efficiency across a wide pH range,with 98%of which eliminated even under neutral conditions(pH 7.0).The high catalytic activity was due to the multilevel porous structure of pollenderived biochar provided enough active sites and allowed for better electron transfer,then increases oxidation ability to promote the ***,the acid microenvironment formed by SO_(4)^(2-)group from Fe/S composite extended the pH range for Fenton reaction,and S^(2-)facilitated the conversion of≡Fe^(3+)to≡Fe^(2+),resulting in remarkable degradation ***,biochar can effectively promote cycling stability by limiting Fe *** work may provide a general strategy for designing 3D framework biochar-based Fe/S catalysts with excellent performance for heterogeneous Fenton reactions.

关键词： Biomass Biochar Fenton reaction Fe_(3)O_(4)/FeS(Fe/S) Phenol degradation

Simultaneous dual-region two-photon imaging of biological dynamics spanning over 9 mm in vivo

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Photonics Research 2024年第3期12卷 456-464页

作者： chi LIU cheng JIN JUNHAO DENG JUNHAO LIANG LIcheng ZHANG LINGJIE KONG State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision InstrumentTsinghua UniversityBeijing 100084China School of Life Sciences Tsinghua UniversityBeijing 100084China Senior Department of Orthopedics The Fourth Medical Center of Chinese PLA General HospitalBeijing 100853China IDG/McGovern Institute for Brain Research Tsinghua UniversityBeijing 100084China

Biodynamical processes,especially in system biology,that occur far apart in space may be highly *** study such biodynamics,simultaneous imaging over a large span at high spatio-temporal resolutions is highly *** example,large-scale recording of neural network activities over various brain regions is indispensable in ***,limited by the field-of-view(FoV)of conventional microscopes,simultaneous recording of laterally distant regions at high spatio-temporal resolutions is highly ***,we propose to extend the distance of simultaneous recording regions with a custom micro-mirror unit,taking advantage of the long working distance of the objective and spatio-temporal *** demonstrate simultaneous dual-region two-photon imaging,spanning as large as 9 mm,which is 4 times larger than the nominal FoV of the *** verify the system performance in in vivo imaging of neural activities and vascular dilations,simultaneously,at two regions in mouse brains as well as in spinal cords,*** adoption of our proposed scheme will promote the study of systematic biology,such as system neuroscience and system immunology.

关键词： recording vivo dynamics

Early peripheral perfusion index predicts 28-day outcome in patients with septic shock

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World Journal of Emergency Medicine 2024年第5期15卷 372-378页

作者： cheng chi Hao Gong Kai Yang Peng Peng Xiaoxia Zhang Department of Emergency Peking University People's HospitalBeijing 100044China Department of Emergency Intensive Care Unit the First Affi liated Hospital of Xinjiang Medical UniversityUrumqi 830000China

BACKGROUND:To investigate the prognostic value of the peripheral perfusion index(PPI)in patients with septic ***:This prospective cohort study,conducted at the emergency intensive care unit of Peking University People's Hospital,recruited 200 patients with septic shock between January 2023 and August *** patients were divided into survival(n=84)and death(n=116)groups based on 28-day *** evaluations included laboratory tests and clinical scores,with lactate and PPI values assessed upon admission to the emergency room and at 6 h and 12 h after *** factors associated with mortality were analyzed using univariate and multivariate Cox regression *** operator characteristic(ROC)curve was used to assess predictive *** rates were compared,and Kaplan-Meier survival plots were ***:Compared to the survival group,patients in the death group were older and had more severe liver damage and coagulation dysfunction,necessitating higher norepinephrine doses and increased fl uid *** lactate levels and lower PPI levels at 0 h,6 h,and 12 h were observed in the death *** Cox regression identifi ed prolonged prothrombin time(PT),decreased 6-h PPI and 12-h PPI as independent risk factors for *** area under the curves for 6-h PPI and 12-h PPI were 0.802(95%CI 0.742-0.863,P<0.001)and 0.945(95%CI 0.915-0.974,P<0.001),respectively,which were superior to Glasgow Coma Scale(GCS),Sequential Organ Failure Assessment(SOFA)scores(0.864 and 0.928).Cumulative mortality in the low PPI groups at 6 h and 12 h was signifi cantly higher than in the high PPI groups(6-h PPI:77.52%vs.22.54%;12-h PPI:92.04%vs.13.79%,P<0.001).CONCLUSION:PPI may have value in predicting 28-day mortality in patients with septic shock.

关键词： Peripheral perfusion index Septic shock Prognosis Predictive value

Amine-functionalized metal organic framework@graphene oxide as filler in PAEK-containing carboxyl group membrane for ultrafiltration with ultra-high permeability and strong fouling resistance

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chinese Journal of Chemical Engineering 2024年第6期70卷 93-103页

作者： Zhaoli Wang Wenjing Li Yi Zhang Yanyin cheng Junjian Yu Tianming Dong Xiaoyu chi Di Liu Zhe Wang School of Chemistry and Life Science Changchun University of TechnologyChangchun 130012China Advanced Institute of Materials Science Changchun University of TechnologyChangchun 130012China Key Laboratory of Advanced Functional Polymer Membrane Materials of Jilin Province Changchun 130012China

Achieving high fouling resistance and permeability using membrane separation technology in water treatment processes remains a *** this work,a novel mixed-matrix membrane(MMM)(poly(arylene ether ketone)[PAEK]-containing carboxyl groups[PAEK-COOH]/UiO-66-NH_(2)@graphene oxide[GO])with superb fouling resistance and high permeability was prepared by the nonsolvent-induced phase separation method,by in-situ growth of UiO-66-NH_(2) on the GO layer,and by preparing hydrophilic *** the basis of the structure and performance analysis of the MMM,the maximum water flux reached 591.25 L·m^(-2)·h^(-1) for PAEK-COOH/UiO-66-NH_(2)@GO,whereas the retention rate for bovine serum albumin increased from 85.40%to 94.87%.As the loading gradually increased,the hydrophilicity of the MMMs increased,significantly enhancing their fouling *** strongest anti-fouling ability observed was 94.74%,which was 2.02 times greater than that of the pure *** the same time,the MMMs contained internal amide and hydrogen bonds during the preparation process,forming a cross-linked structure,which further enhanced the mechanical strength and chemical *** summary,the MMMs with high retention rate,strong permeability,and anti-fouling ability were successfully prepared.

关键词： Poly(arylene ether ketone)-containing Carboxyl groups(PAEK-COOH) UiO-66-NH_(2)@graphene oxide Hydrophilic modification Ultra-high selectivity Strong anti-fouling

Deep Transfer Learning Models for Mobile-Based Ocular Disorder Identification on Retinal Images

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Computers, Materials & Continua 2024年第7期80卷 139-161页

作者： Roseline Oluwaseun Ogundokun Joseph Bamidele Awotunde Hakeem Babalola Akande cheng-chi Lee Agbotiname Lucky Imoize Department of Multimedia Engineering Kaunas University of TechnologyKaunas44249Lithuania Department of Computer Science Landmark UniversityOmu Aran251103Nigeria Department of Computer Science Faculty of Information and Communication SciencesUniversity of IlorinIlorin240003Nigeria Department of Telecommunication Science University of IlorinIlorin230003Nigeria Department of Library and Information Science Fu Jen Catholic UniversityNew Taipei City24205TaiwanChina Department of Computer Science and Information Engineering Fintech and Blockchain Research CenterAsia UniversityTaichung City41354TaiwanChina Department of Electrical and Electronics Engineering Faculty of EngineeringUniversity of LagosAkokaLagos100213Nigeria Department of Electrical Engineering and Information Technology Institute of Digital CommunicationRuhr UniversityBochum44801Germany

Mobile technology is developing *** phone technologies have been integrated into the healthcare industry to help medical ***,computer vision models focus on image detection and classification ***2 is a computer vision model that performs well on mobile devices,but it requires cloud services to process biometric image information and provide predictions to *** leads to increased *** biometrics image datasets on mobile devices will make the prediction faster,but mobiles are resource-restricted devices in terms of storage,power,and computational ***,a model that is small in size,efficient,and has good prediction quality for biometrics image classification problems is *** pre-trained CNN(PCNN)MobileNetV2 architecture combined with a Support Vector Machine(SVM)compacts the model representation and reduces the computational cost and memory *** proposed novel approach combines quantized pre-trained CNN(PCNN)MobileNetV2 architecture with a Support Vector Machine(SVM)to represent models efficiently with low computational cost and *** contributions include evaluating three CNN models for ocular disease identification in transfer learning and deep feature plus SVM approaches,showing the superiority of deep features from MobileNetV2 and SVM classification models,comparing traditional methods,exploring six ocular diseases and normal classification with 20,111 images postdata augmentation,and reducing the number of trainable *** model is trained on ocular disorder retinal fundus image datasets according to the severity of six age-related macular degeneration(AMD),one of the most common eye illnesses,Cataract,Diabetes,Glaucoma,Hypertension,andMyopia with one class *** the experiment outcomes,it is observed that the suggested MobileNetV2-SVM model size is *** testing accuracy for MobileNetV2-SVM,InceptionV3,and MobileNetV2 is 90.11%,86.88%,a

关键词： Retinal images ocular disorder deep transfer learning disease identification mobile device

Addressable structured light system using metasurface optics and an individually addressable VCSEL array

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Photonics Research 2024年第6期12卷 1129-1137页

作者： CHENYANG WU XUANLUN HUANG YIPENG JI TINGYU cheng JIAXING WANG NAN chi SHAOHUA YU CONNIE J.CHANG-HASNAIN School of Information Science and Technology Fudan UniversityShanghai 200433China Berxel Photonics Co. Ltd.Shenzhen 518071China Peng cheng Laboratory Shenzhen 518055China chinese University of Hong Kong Shenzhen 518172China

Structured-light(SL)based 3D sensors have been widely used in many *** SL is the most widely deployed among all SL sensors due to its light weight,compact size,fast video rate,and low *** transmitter(known as the dot projector)consists of a randomly patterned vertical-cavity surface-emitting laser(VCSEL)array multiplicated by a diffractive optical element(DOE)with a fixed repeated *** that the separation of any two speckles is only one known and fixed number(albeit random),there are no other known scales to cal-ibrate or ***,typical SL sensors require extensive in-factory calibrations,and the depth resolution is limited to 1 mm at-60 cm *** this paper,to the best of our knowledge,we propose a novel dot projector and a new addressable SL(ASL)3D sensor by using a regularly spaced,individually addressable VCSEL array,multiplicated by a metasurface-DOE(MDOE)into a random pattern of the *** turning on or off the VCSELs in the array provides multiple known distances between neighboring speckles,which is used as a“built-in caliper”to achieve higher accuracy of *** as a precise“vernier caliper,”the addressable VCSEL array enables fine control over speckle positions and high detection *** experimentally dem-onstrated that the proposed method can result in sub-hundred-micron level *** new concept opens new possibilities for applications such as 3D computation,facial recognition,and wearable devices.

关键词： speckle light surface

Existence of long-range magnetic order in Heisenberg spin nanoribbons with edge modification

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Communications in Theoretical Physics 2024年第7期76卷 134-144页

作者： Da-cheng Ma Ling-yi Cui Chu-xiao Sun Xiao-dan chi Zheng-Nan XianYu An Du College of Science Northeastern UniversityShenyang 110819China Department of Basic Science Dalian Naval AcademyDalian 116018China Department of Physics College of SciencesShenyang University of Chemical TechnologyShenyang 110142China National Frontiers Science Center for Industrial Intelligence and Systems Optimization Northeastern UniversityChina Key Laboratory of Data Analytics and Optimization for Smart Industry(Northeastern University) Ministry of EducationChina

Long-range magnetic order appears on a side decorated Heisenberg spin nanoribbon at nonzero temperature,although no spontaneous magnetization exists in a one-or two-dimensional isotropic Heisenberg model at any nonzero temperature according to the Mermin-Wagner *** use of the spin Green's function method,we calculated the magnetizations of Heisenberg nanoribbons decorated by side spins with single-ion anisotropy and found that the system exhibits a nonzero transition temperature,whether the decorated edge spins of the system link together or separate from each *** the width of the nanoribbon achieves infinite limit,the transition temperatures of the system tend to the same finite constant eventually whether one edge or both edges are decorated by side spins in the *** results reveal that the magnetism of a low-dimensional spin system is different from that of a threedimensional spin *** the single-ion anisotropy of edge spins in a Heisenberg spin nanoribbon can be modulated by an electric field experimentally,various useful long-range magnetic orders of the system can be *** work can provide a detailed theoretical basis for designing and fabricating next-generation low-dimensional magnetic random-access memory.

关键词： Nanoribbon magnetic anisotropy long-range magnetic order Heisenberg model transition temperature

A range and depth estimation method using the time delay structure of bottom reflection in deep sea bottom bounce area

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chinese Journal of Acoustics 2024年第3期43卷 275-289页

作者： XIE Qichen chi cheng ZHANG Bo HUANG Haining Institute of Acoustics Chinese Academy of SciencesBeijing100190 Key Laboratory of Science and Technology on Advanced Underwater Acoustic Signal Processing Chinese Academy of SciencesBeijing100190 University of chinese Academy of Sciences Beijing100049

When the source-receiver depth relationship is unknown,using the time delay differences for distance and depth estimation may result in a pseudo *** address the issue,a method for directly estimating distance and depth using four time delay differences has been *** method analyzes the relationship of four time delay differences between multipath,by utilizing the difference in the same time delay difference between the pseudo source and the true position,a fuzzy plane is constructed for *** pseudo source can be eliminated without determining the source-receiver depth relationship,which can be achieved on a single *** effectiveness of the method is verified through simulation experiments and error *** sea experiment shows that the method successfully achieves distance and depth estimation of targets ranging from 11.0 km to 16.5 km on two single hydrophones at different depths,with root mean square errors of less than 1.1 km and 54 m,respectively.

关键词： delay estimation method