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The recirculation flow after different cross-section shaped high-rise buildings with applications to ventilation assessment and drag parameterization

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Building Simulation 2024年第4期17卷 509-524页

作者： Keyi Chen Ziwei Mo jian Hang School of Atmospheric Sciences Sun Yat-sen University&Southern Marine Science and Engineering Guangdong LaboratoryZhuhai519082China Key Laboratory of Tropical Atmosphere-Ocean System Ministry of EducationZhuhai519000China

The building cross-section shape significantly affects the flow characteristics around buildings,especially the recirculation region behind the high-rise *** generic building shapes including square,triangle,octagon,T-shaped,cross-shaped,#-shaped,H-shaped and L-shaped are examined to elucidate their effects on the flow patterns,recirculation length L and areas A using computational fluid dynamics(CFD)simulations with Reynolds-averaged Navier-Stokes(RANS)*** sizes and positions of the vortexes behind the buildings are found to be substantially affected by the building shapes and subsequently changing the recirculation *** recirculation length L is in the range of 1.6b-2.6b with an average of *** maximum L is found for L-shaped building(2.6b)while the shortest behind octagon building(1.6b).The vertical recirculation area Av is in the range of 1.5b^(2)-3.2b^(2)and horizontal area Ah in 0.9b^(2)-2.2b^(2).The L,Av and Ah generally increase with increasing approaching frontal area when the wind direction changes but subject to the dent structures of the#-shaped and cross-shaped *** area-averaged wind velocity ratio(AVR),which is proposed to assess the ventilation performance,is in the range of 0.05 and 0.14,which is around a three-fold difference among the different building *** drag coefficient parameterized by Ah varies significantly,suggesting that previous models without accounting for building shape effect could result in large uncertainty in the drag *** findings provide important reference for improving pedestrian wind environment and shed some light on refining the urban canopy parameterization by considering the building shape effect.

关键词： recirculation region cross-section shape ventilation assessment drag parameterization computational fluid dynamics

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Recent progress in self-propelled particles

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Journal of Hydrodynamics 2024年第1期36卷 61-77页

作者： Zhen-yu Ouyang jian-zhong Lin Laboratory of Impact and Safety Engineering Ministry of EducationNingbo UniversityNingbo315201China Department of Mechanics State Key Laboratory of Fluid Power and Mechatronic SystemsZhejiang UniversityHangzhou310027China

Self-propelled particles are commonly found in a large number of planktonic organisms such as bacteria,fungi,and algae in nature,and researchers have taken a long interest in exploring their swimming mechanisms for more than a *** in the past 20 years,with the development of computational fluid dynamics and flow display technology,as well as the need for the design of synthetic self-propelled particles and micro-swimming devices,self-propelled particles have become the forefront and hotspot of current research in the field of fluid *** paper first introduces the swimming characteristics of common self-propelled particles,leading to a classic“squirmer”type self-propelled particle *** this basis,a systematic introduction and summary of the theoretical and numerical simulation research of“squirmer”will be ***,the main challenges and opportunities faced by the current research will be summarized.

关键词： Self-propelled particles multiphase flow hydrodynamic interaction

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Active Fault Tolerant Nonsingular Terminal Sliding Mode Control for Electromechanical System Based on Support Vector Machine

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 189-203页

作者： jian Hu Zhengyin Yang jianyong Yao School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China

Effective fault diagnosis and fault-tolerant control method for aeronautics electromechanical actuator is concerned in this *** borrowing the advantages of model-driven and data-driven methods,a fault tolerant nonsingular terminal sliding mode control method based on support vector machine(SVM)is proposed.A SVM is designed to estimate the fault by off-line learning from small sample data with solving convex quadratic programming method and is introduced into a high-gain observer,so as to improve the state estimation and fault detection accuracy when the fault *** state estimation value of the observer is used for state reconfiguration.A novel nonsingular terminal sliding mode surface is designed,and Lyapunov theorem is used to derive a parameter adaptation law and a control *** is guaranteed that the proposed controller can achieve asymptotical stability which is superior to many advanced fault-tolerant *** addition,the parameter estimation also can help to diagnose the system faults because the faults can be reflected by the parameters *** comparative simulation and experimental results illustrate the effectiveness and advancement of the proposed controller compared with several other main-stream controllers.

关键词： Aeronautics electromechanical actuator Fault tolerant control Support vector machine State observer Parametric uncertainty

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Efficient and selective H_(2)O_(2)production through uranyl-assisted photocatalytic oxygen reduction reaction process in a uranium-organic framework

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Science China Chemistry 2024年第7期67卷 2274-2281页

作者： jianxin Song Chao Liang Baoyu Li Xuemin wang min Lei Lisha jiang Zhenyu Li Yugang Zhang jian Xie Zuju Ma Xing Dai Yanlong wang Shuao wang Wei Liu School of Environmental and Materials Engineering Yantai UniversityYantai 264005China State Key Laboratory of Radiation Medicine and Protection School for Radiological and Interdisciplinary Sciences(RAD-X)and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education InstitutionsSoochow UniversitySuzhou 215123China School of Life and Environmental Sciences Shaoxing UniversityShaoxing 312000China School of Nuclear Science and Technology Xi’an Jiaotong UniversityXi’an 710049China

Harnessing solar energy by photocatalytically converting oxygen and water into high-value-added H_(2)O_(2)is a promising way of alleviating both environmental and energy *** is worth noting that suppressing detrimental side reactions,such as the generation of·O_(2)^(-),is a critical approach to enhancing H_(2)O_(2)***,a 2-fold interpenetrating 3D uranium-organic framework(YTU-W-1)was developed and introduced for photocatalytic H_(2)O_(2)*** material demonstrates a different photocatalytic mechanism when employing uranyl as an initiator,as compared with the conventional semiconductor photocatalytic pathway involving photo-generated charge *** from the strong hydrogen abstraction effect of the U≡O·and the direct one-step oxygen reduction pathway,YTU-W-1 exhibits enhanced photocatalytic performance for H_(2)O_(2)production with yield efficiency of 221μmol h^(-1)g^(-1).Furthermore,YTU-W-1 displays a high H_(2)O_(2)selectivity of 68%,confirmed by rotating ring-disk electrode(RRDE)*** were used to elucidate the critical role of uranyl in the photocatalytic oxygen reduction reaction for H_(2)O_(2)*** research introduces an innovative approach to photo-driven H_(2)O_(2)production,underscoring the potential for heterogeneous catalysts to engage in photocatalytic reactions independently of photogenerated charge carriers.

关键词： uranyl metal-organic frameworks oxygen reduction reaction photocatalytic H_(2)O_(2)synthesis

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Accurate simulations of pure-viscoacoustic wave propagation in tilted transversely isotropic media

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Petroleum Science 2024年第2期21卷 866-884页

作者： Qiang Mao jian-Ping Huang Xin-Ru Mu Ji-Dong Yang Yu-jian Zhang Geosciences Department China University of Petroleum(East China)Qingdao266580ShandongChina Pilot National Laboratory for Marine Science and Technology(Qingdao) Qingdao266207ShandongChina

Forward modeling of seismic wave propagation is crucial for the realization of reverse time migration(RTM) and full waveform inversion(FWI) in attenuating transversely isotropic media. To describe the attenuation and anisotropy properties of subsurface media, the pure-viscoacoustic anisotropic wave equations are established for wavefield simulations, because they can provide clear and stable wavefields. However, due to the use of several approximations in deriving the wave equation and the introduction of a fractional Laplacian approximation in solving the derived equation, the wavefields simulated by the previous pure-viscoacoustic tilted transversely isotropic(TTI) wave equations has low accuracy. To accurately simulate wavefields in media with velocity anisotropy and attenuation anisotropy, we first derive a new pure-viscoacoustic TTI wave equation from the exact complex-valued dispersion formula in viscoelastic vertical transversely isotropic(VTI) media. Then, we present the hybrid finite-difference and low-rank decomposition(HFDLRD) method to accurately solve our proposed pure-viscoacoustic TTI wave equation. Theoretical analysis and numerical examples suggest that our pure-viscoacoustic TTI wave equation has higher accuracy than previous pure-viscoacoustic TTI wave equations in describing q P-wave kinematic and attenuation characteristics. Additionally, the numerical experiment in a simple two-layer model shows that the HFDLRD technique outperforms the hybrid finite-difference and pseudo-spectral(HFDPS) method in terms of accuracy of wavefield modeling.

关键词： Pure-viscoacoustic TTI wave equation Attenuation anisotropy Seismic modeling Low-rank decomposition method

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Xiao Tan San Jie Fang Hampers the Growth of Colon Cancer Stem Cells through the Wnt/β-catenin Signaling Pathway

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World Journal of Traditional Chinese Medicine 2024年第2期10卷 171-179页

作者： Yu-Qi Zhou Jun-Fei Yuan Hong-Shi Shen Ya-Ping wang Han-Fei Shi De-jian Pan min Ye Department of Hematology and Oncology The 904^(th) Hospital of PLA Joint Logistic Support ForceWuxiJiangsuChina Department of Clinical Laboratory The 904^(th)Hospital of PLA Joint Logistic Support ForceWuxiJiangsuChina Department of Traditional Chinese Medicine Second Affiliated Hospital of Naval Medical UniversityShanghaiChina

Objective: The purpose of this research was to examine the potential anticancer properties of Xiao Tan San Jie Fang(XTSJF) and its potential mechanism of action against colorectal cancer. Materials and Methods: HCT116 cells were induced into HCT116 spheres in DMEM/F12 medium by treatment with epidermal growth factor + fibroblast growth factor + leukemia inhibitory factor + B27. The proliferation ability and stemness of HCT116 spheres was examined. Various concentrations of XTSJF were used to treat HCT116 spheres to observe the impact on proliferation, apoptosis, and expression of stem cell markers. Next, Wnt/β-catenin pathway-related factor proteins were detected. Results: The findings revealed that XTSJF suppressed cell growth and induced cell death in HCT116 cells in a dosage-dependent manner. Similarly, XTSJF promotes apoptosis, inhibits cell proliferation, prolongs survival, and maintains the expression of stem cells through the Wnt/-catenin/TCF4 axis. XTSJF also inhibits AKT activity and subsequently activates glycogen synthesis kinase-3β expression, inhibiting Wnt/beta-catenin pathway activity and downstream target gene transcript expression. The Wnt/β-catenin signaling pathway is inhibited by the XTSJF, leading to the suppression of colon cancer stem cell proliferation. Conclusion: Xiaotan Sanjie Prescription inhibited colon cancer stem cell growth through Wnt/β-catenin signaling pathway.

关键词： Apoptosis colorectal cancer proliferation traditional Chinese medicine Wnt/β-catenin signaling

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The evolution and functional divergence of 10 Apolipoprotein D-like genes in Nilaparvata lugens

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Insect Science 2024年第1期31卷 91-105页

作者： Jia-Bao Lu Peng-Peng Ren Qiao Li Fang He Zhong-Tian Xu Sai-Nan wang jian-Ping Chen Jun-min Li Chuan-Xi Zhang Citrus Research Institute Southwest University/Chinese Academy of Agricultural SciencesNational Engineering Research Center for CitrusChongqingChina Technology Center of Wuhan Customs District HubeiChina Institute of Insect Science Zhejiang UniversityHangzhouChina

Apolipoprotein D(ApoD),a member of the lipocalin superfamily of proteins,is involved in lipid transport and stress *** only a single copy of the ApoD gene is found in humans and some other vertebrates,there are typically several ApoD-like genes in *** date,there have been relatively few studies that have examined the evolution and functional differentiation of ApoD-like genes in insects,particularly hemi-metabolous *** this study,we identified 10 ApoD-like genes(NlApoD1−10)with distinct spatiotemporal expression patterns in Nilaparvata lugens(BPH),which is an important pest of ***1−10 were found to be distributed on 3 chromosomes in a tandem array of NlApoD1/2,NlApoD3−5,and NlApoD7/8,and show sequence and gene structural divergence in the coding regions,indicating that multiple gene duplication events occurred during *** analysis revealed that NlApoD1−10 can be clustered into 5 clades,with NlApoD3−5 and NlApoD7/8 potentially evolving exclusively in the Delphacidae *** screening using an RNA interference approach revealed that only NlApoD2 was essential for BPH development and survival,whereas NlApoD4/5 are highly expressed in testes,and might play roles in ***,stress response analysis revealed that NlApoD3−5/9,NlApoD3−5,and NlApoD9 were up-regulated after treatment with lipopolysaccharide,H2O2,and ultraviolet-C,respectively,indicating their potential roles in stress resistance.

关键词： Apolipoprotein D BPH evolution functional divergence gene duplication NIApoD

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A product version of the Hilton-Milner-Frankl theorem

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Science China Mathematics 2024年第2期67卷 455-474页

作者： Peter Frankl jian wang Alfréd Rényi Institute of Mathematics Hungarian Academy of SciencesBudapest H-1053Hungary Department of Mathematics Taiyuan University of TechnologyTaiyuan 030024China

Two families F and G of k-subsets of {1, 2,..., n} are called non-trivial cross t-intersecting if|F ∩ G|≥t for all F ∈ F, G ∈ G and | ∩ {F : F ∈ F}| < t, | ∩ {G : G ∈ G}| < t. In the present paper,we determine... 详细信息

Two families F and G of k-subsets of {1, 2,..., n} are called non-trivial cross t-intersecting if|F ∩ G|≥t for all F ∈ F, G ∈ G and | ∩ {F : F ∈ F}| mine the maximum product of the sizes of two non-trivial cross t-intersecting families of k-subsets of{1, 2,..., n} for n≥4(t + 2)2k2, k≥5, which is a product version of the Hilton-Milner-Frankl theorem.

关键词： extremal set theory cross t-intersecting family product version non-trivial

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Mobility edges and localization characteristics in one-dimensional quasiperiodic quantum walk

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Chinese Physics B 2024年第6期33卷 156-160页

作者：崔鑫辉王慧敏李志坚 Institute of Theoretical Physics State Key Laboratory of Quantum Optics and Quantum DevicesShanxi UniversityTaiyuan 030006China

We construct a one-dimensional quasiperiodic quantum walk to investigate the localization–delocalization *** inverse participation ratio and Lyapunov exponent are employed as two indexes to determine the mobility edge, a critical energy to distinguish the energy regions of extended and localized states. The analytical solution of mobility edge is obtained by the Lyapunov exponents in global theory, and the consistency of the two indexes is confirmed. We further study the dynamic characteristics of the quantum walk and show that the probabilities are localized to some specific lattice sites with time evolution. This phenomenon is explained by the effective potential of the Hamiltonian which corresponds to the phase in the coin operator of the quantum walk.

关键词： quantum walk mobility edges quasiperiodicity

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Endoscopic treatment of extreme esophageal stenosis complicated with esophagotracheal fistula: A case report

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World Journal of Gastrointestinal Surgery 2024年第1期16卷 239-247页

作者： Jia-Heng Fang Wei-min Li Cheng-Hai He jian-Liang Wu Yun Guo Zhi-Chao Lai Guo-Dong Li Department of Gastroenterology Hangzhou Normal University Affiliated HospitalHangzhou 310000Zhejiang ProvinceChina

BACKGROUND At present,there is no unified and effective treatment for extreme corrosive esophageal stenosis(CES)with esophagotracheal fistula(ETF).This case had extreme and severe esophageal stenosis(ES)and ETF after ingesting an enzyme-based chemical detergent,resulting in a serious pulmonary infection and severe *** gastrointestinal imaging showed that he had an ETF,and endoscopy showed that he had extreme and severe esophageal *** case was complex and difficult to *** to the domestic and foreign lite-rature,there is no universal treatment that is *** SUMMARY A patient came to our hospital with extreme ES,an ETF,and severe malnutrition complicated with pulmonary tuberculosis 1 mo after the consumption of an enzy-me-based *** ES was serious,and the endoscope was unable to pass through the *** treated him by endoscopic incision method(EIM),esophageal stent placement(ESP),and endoscopic balloon dilation(EBD)by using the bronchoscope and *** treatment not only closed the ETF,but also expanded the esophagus,with minimal trauma,greatly reducing the pain of the *** to the literature,there are no similar reported *** We report,for the first time,a patient with extreme CES complicated with ETF,where the endoscope could not be passed through his esophagus but he could be examined by bronchoscopy and treated by EIM,ESP,and EBD.

关键词： Extreme corrosive esophageal stenosis Esophagotracheal fistula Endoscopic incision method Esophageal stent placement Endoscopic balloon dilation Case report

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