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Effect of geometry simplification and boundary condition specification on flow field and aerodynamic noise in the train head and bogie region of high-speed trains

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第9期25卷 716-731页

作者： Jiawei shi Yuan HE Jiye ZHANG tian li State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu 610031China Institute of Sound and Vibration Research Faculty of Engineering and Physical SciencesUniversity of SouthamptonSouthampton SO171BJUK

The purpose of this study is to determine a suitable modeling method to make computational fluid dynamics(CFD)simulation more efficient for aeroacoustics optimization of the bogie region of high-speed *** this end,four modeling methods are considered,which involve different geometry simplifications and boundary condition *** corresponding models are named the three-car marshalling model,computational domain shortening model,carbody shortening model,and sub-domain *** the detached eddy simulation(DES)model and Ffowcs Williams-Hawkings(FW-H)equation,the unsteady flow field and far-field noise of the four models are *** evaluate the effect of the different modeling methods,the time-averaged flow field,fluctuating flow field,and far-field noise results of the four models are compared and analyzed in detail with the results of the three-car marshalling model used as basis for *** results show that the flow field results of the bogie region predicted by the four models have relatively high ***,the usage of the non-time varying outlet boundary conditions in the computational domain shortening model and sub-domain model could affect the pressure fluctuation on the upstream carbody *** only the bogie region is used as the source surface,the differences between the far-field noise results of the three simplified models and the three-car marshalling model are all within 1 dB;when the train head is used as the source surface,the results of the carbody shortening model and the three-car marshalling model are more consistent.

关键词： Bogie region Train head Flow field Aerodynamic noise Geometry simplification Boundary conditions

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Ferroelectric perovskite PbTiO_(3)for advanced photocatalysis

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Rare Metals 2024年第9期43卷 4038-4055页

作者： Shuang Zhao shi-shi Shen Lu Han Bo-Chao tian Na li Wei Chen Xi-Bao li School of Materials and Metallurgy University of Science and Technology LiaoningAnshan 114051China School of Materials Science and Engineering Nanchang Hangkong UniversityNanchang 330063China Department of Chemistry National University of SingaporeSingapore 117543Singapore

The ferroelectric semiconductor material PbTiO_(3)exhibits remarkable spontaneous polarization and photoelectric properties,positioning it as a promising polar *** internal electric field of ferroelectrics can separate photocarriers and enhance the catalytic performance of ***,when combined with other semiconductors,PbTiO_(3)contributes to the construction of a depolarization field,extending the catalytic applications of PbTiO_(3)***_(3)exhibits optical absorption,semiconductor,and piezoelectric *** piezoelectric polarization field enhances charge separation,modulates band structure,surface charge conduction,and heterojunction interface charge conduction,thereby amplifying photocatalytic *** paper begins by examining the structure,properties,and preparation methods of PbTiO_(3).Subsequently,it delves into the optimization of PbTiO_(3)'s structure and performance,exploring applications in photocatalysis as a ferroelectric *** is placed on the detailed discussion of surface modification,heterostructure formation,and ferroelectric polarization of PbTiO_(3)*** aspects are thoroughly explored for their role in regulating activity and optimizing the performance of photocatalysis and photopiezoelectric *** conclusion,the paper addresses the current research status of PbTiO_(3)ferroelectric materials and highlights the challenges that lie *** intention is to provide valuable references for the ongoing research in PbTiO_(3)ferroelectric materials.

关键词： PbTiO_(3) Ferroelectric polarization Photocatalysis Piezoelectric catalysis Polarization

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Buckling optimization of curvilinear fiber-reinforced composite structures using a parametric level set method

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Frontiers of Mechanical Engineering 2024年第1期19卷 149-160页

作者： Ye tian Tielin shi Qi XIA State Key Laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China

Owing to their excellent performance and large design space,curvilinear fiber-reinforced composite structures have gained considerable attention in engineering fields such as aerospace and *** addition to the stiffness and strength of such structures,their stability also needs to be taken into account in the *** study proposes a level-set-based optimization framework for maximizing the buckling load of curvilinear fiber-reinforced composite *** the proposed method,the contours of the level set function are used to represent fiber *** a composite laminate with a certain number of layers,one level set function is defined by radial basis functions and expansion coefficients for each ***,the fiber angle at an arbitrary point is the tangent orientation of the contour through this *** the finite element of buckling,the stiffness and geometry matrices of an element are related to the fiber angle at the element *** study considers the parallelism constraint for fiber *** the sensitivity calculation of the objective and constraint functions,the method of moving asymptotes is utilized to iteratively update all the expansion coefficients regarded as design *** numerical examples under different boundary conditions are given to validate the proposed *** show that the optimized curved fiber paths tend to be parallel and equidistant regardless of whether the composite laminates contain holes or ***,the buckling resistance of the final design is significantly improved.

关键词： buckling optimization curvilinear fiber composite structure level set method manufacturing constraint

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Regio-and Stereoselective Polymerization of Bio-based Ocimene by Rare-Earth Metal Catalysts

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Chinese Journal of Polymer Science 2024年第2期42卷 223-229,I0008页

作者： Qi-Yuan Wang li-Peng Sang Zhen Zhang Yang Jiang Hui tian Xia Zhao Xiang Guo shi-Hui li State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei230026China Science and Technology on Aerospace Chemical Power Laboratory Hubei Institute of Aerospace ChemotechonologyXiangyang441003China Shanxi Coal Chemical Industry Technology Research Institute Xi’an710000China Hubei Institute of Aerospace Chemotechonology Xiangyang441003China

Coordination polymerization of renewable β-ocimene has been investigated using asymmetric diiminophosphinate lutetium complex1, β-diketiminate yttrium complex 2, bis(phosphino)carbazolide yttrium complex 3, half-sandwich benzyl fluorenyl scandium complex 4 and pyridyl-methylene-fluorenyl rare-metal complexes 5a–5c. Complexes 1, 4 and 5a–5c show trans-1,2-regioselectivities and high activities, of which 5c exhibits excellent isoselectivity(mmmm>99%). Conversely, complexes 2 and 3 promote β-ocimene polymerization to produce isotactic cis-1,4-polyocimenes(cis-1,4>99%, mm>95%). Diblock copolymers cis-1,4-PIP-block-cis-1,4-POc and cis-1,4-PBD-block-cis-1,4-POc are obtained in one-pot reactions of β-ocimene with isoprene and butadiene using complex 3. Epoxidation and hydroxylation of polyocimene afford functionalized polyolefins with enhanced T_(g)(from-20 ℃ to 79 ℃ and 74 ℃) and hydrophilicity.

关键词： Biobased monomer Terpenes Ocimene Rare-earths Polymerization Regio/stereoselectivity Elastomer

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White matter disease derived from vascular and demyelinating origins

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Stroke & Vascular Neurology 2024年第4期9卷 344-350页

作者： lin-Jie Zhang De-Cai tian li Yang Kaibin shi Yaou liu Yilong Wang Fu-Dong shi Department of Neurology Tianjin Medical University General HospitalTianjinTianjinChina National Clinical Research Center for Neurological Diseases of China Beijing Tiantan HospitalCapital Medical UniversityBeijingBeijingChina

Damage or microstructural alterations of the white matter can cause dysfunction of the intrinsic neural networks in a condition termed as white matter disease(WMD).Frequently detected on brain computed tomography and magnetic resonance imaging scans,WMD is commonly presented in inflammatory demyelinating diseases like multiple sclerosis(MS)and vascular diseases such as cerebral small vessel disease(CSVD).Prevention of MS and CSVD progression requires early treatments with drastically different medications and approaches,as such,early and accurate diagnosis of WMD,derived from vascular or demyelinating etiologies,is of paramount ***,the clinical and imaging similarities between MS,especially during the early stage,and CSVD,pose a significant dilemma in differentiating these two *** this review,we attempt to summarize and contrast the distinguishing features of MS and CSVD for aiding accurate diagnosis to ensure timely corresponding management in the early stages of MS and CSVD.

关键词： diagnosis myelin alterations

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Application of Natural Medicinal Plants Active Ingredients in Oral Squamous Cell Carcinoma

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Chinese Journal of Integrative Medicine 2024年第9期30卷 852-864页

作者： REN Qun-li li Xiao-lan tian tian li Shuang shi Rong-yi WANG Qian ZHU Yuan WANG Miao HU Huan liU Jian-guo School of Stomatology Zunyi Medical UniversityZunyiGuizhou Province563000China Microbial Resources and Drug Development Key Laboratory of Guizhou Tertiary Institution Zunyi Medical UniversityZunyiGuizhou Province563000China School of Basic Medicine Zunyi Medical UniversityZunyiGuizhou Province563000China

Oral squamous cell carcinoma(OSCC)is the most common malignant cancer of the head and neck,with high morbidity and mortality,ranking as the sixth most common cancer in the *** treatment of OSCC is mainly radiotherapy,chemotherapy and surgery,however,the prognosis of patients is still poor and the recurrence rate is *** paper reviews the range of effects of natural medicinal plant active ingredients(NMPAIs)on OSCC cancer,including the types of NMPAIs,anti-cancer mechanisms,involved signaling pathways,and clinical *** NMPAIs include terpenoids,phenols,flavonoids,glycosides,alkaloids,coumarins,and volatile *** active ingredients inhibit proliferation,induce apoptosis and autophagy,inhibit migration and invasion of OSCC cells,and regulate cancer immunity to exert anti-cancer *** mechanism involves signaling pathways such as mitogen-activated protein kinase,phosphatidylinositol 3 kinase/protein kinase B,nuclear factor kappa B,miR-22/WNT1/β-catenin and Nrf2/***,NMPAIs can inhibit the growth of OSCC,and the combined drug is more *** medicinal plants are promising candidates for the treatment of OSCC.

关键词： natural medicinal plant active ingredients oral squamous cell carcinoma mechanism signaling pathway review

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Elemene Antitumor Drugs Development Based on "Molecular Compatibility Theory" and Clinical Application: A Retrospective and Prospective Outlook

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Chinese Journal of Integrative Medicine 2024年第1期30卷 62-74页

作者： JIANG Xiao-ying shi li-ping ZHU Jun-long BAI Ren-ren XIE tian School of Pharmacy Hangzhou Normal UniversityHangzhou(311121)China Key Laboratory of Elemene Class Anti-cancer Chinese Medicines Engineering Laboratory of Development and Application of Traditional Chinese MedicinesCollaborative Innovation Center of Traditional Chinese Medicines of Zhejiang ProvinceHangzhou Normal UniversityHangzhou(311121)China Good Clinical Practice Center Affliliated Hospital of Nanjing University of Chinese MedicineNanjing(210000)China

Elemene, derived from Curcuma wenyujin, one of the "8 famous genuine medicinal materials of Zhejiang province," exhibits remarkable antitumor activity. It has gained wide recognition in clinical practice for effectiveness on tumors. Dr. XIE tian introduced the innovative concept of "molecular compatibility theory" by combining Chinese medicine principles, specifically the "monarch, minister, assistant, and envoy" theory, with modern biomedical technology. This groundbreaking approach, along with a systematic analysis of Chinese medicine and modern biomedical knowledge, led to the development of elemene nanoliposome formulations. These novel formulations offer numerous advantages, including low toxicity, well-defined composition, synergistic effects on multiple targets, and excellent biocompatibility. Following the principles of the "molecular compatibility theory", further exploration of cancer treatment strategies and methods based on elemene was undertaken. This comprehensive review consolidates the current understanding of elemene's potential antitumor mechanisms, recent clinical investigations, advancements in drug delivery systems, and structural modifications. The ultimate goal of this review is to establish a solid theoretical foundation for researchers, empowering them to develop more effective antitumor drugs based on the principles of "molecular compatibility theory".

关键词： molecular compatibility theory Chinese integrative medicine elemene antitumor activity drug delivery structural modification

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Wet deposition and scavenging ratio of air pollutants during an extreme rainstorm in the North China Plain

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Atmospheric and Oceanic Science Letters 2017年第5期10卷 348-353页

作者： Pan Yue-Peng Zhu Xia-Ying tian shi-li Wang li-li Zhang Guo-Zhong Zhou Yan-Bo Xu Peng Hu Bo Wang Yue-Si State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC) Institute of Atmospheric Physics ChineseAcademy of Sciences Beijing China National Climate Center China Meteorological Administration Beijing China

Atmospheric wet deposition plays an important role in the supply of nutrients and toxic substances to terrestrial and aquatic environments. Although long-term（e.g. annual, multi-year） wet deposition is recorded well, pronounced and short-term changes in precipitation chemistry are less well investigated. In the present study, the precipitation chemistry and scavenging ratio of air pollutants were observed during an extreme torrential rain event（325.6 mm at the observation site） that occurred over 19–21 July 2016 in the North China Plain（NCP）. The scavenging ratio of particles showed a similar spatial distribution to that of the precipitation amount in the NCP, indicating the efficient removal of particulate matter due to the large amount and precipitation intensity of the storm. In addition, the scavenging ratio of water soluble ions was larger than that of organics and gaseous pollutants such as SO_2 and NO_2, likely due to their differences in water ***, raindrops incorporated more aerosol sulfate than gaseous compounds. Due to the heavy precipitation amount, almost all species in rainwater during this storm showed their lowest concentration but the highest flux compared with other rain events, indicating an important role played by this storm in terms of the substances received by the terrestrial and marine ecosystems of the region. However, the contribution of this storm to the annual chemical flux was lower than that of precipitation amount, indicating that the atmospheric compounds were scavenged below-cloud first and were then diluted by the cloud/rainwater. Future studies are needed in the context of the occurrence of extreme rainfall events in the NCP from the perspective of climate variability.

关键词： Extreme precipitation event rain chemistry wet deposition

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Systematic study of the synthesis of heavy and superheavy nuclei in 48Ca-induced fusion-evaporation reactions

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Nuclear Science and Techniques 2024年第7期35卷 157-172页

作者： shi-Hao Zhu tian-liang Zhao Xiao-Jun Bao Department of Physics Collaborative Innovation Center for Quantum EffectsKey Laboratory of Low Dimensional Quantum Structures and Quantum Control of Ministry of EducationHunan Normal UniversityChangsha410081China School of Nuclear Science and Technology Lanzhou UniversityLanzhou730000China School of Physics Xi’an Jiaotong UniversityXi’an710049China

We systematically studied the evaporation residue cross sections of ^(48)Ca-induced reactions on lanthanide and actinide target nuclei under the Dinuclear System(DNS)model framework to check the reliability and applicability of the *** produce new proton-rich Fl and Lv isotopes through hot fusion reactions in the superheavy element region with Z≥104,we utilized the reactions ^(48)Ca+^(236,238,239) Pu and ^(48)Ca+^(242,243,244,250) ***,owing to the detection limit of available equipment(0.1 pb),only 283Fl and 287−289Lv,which have the maximum evaporation residue cross section values of 0.149,0.130,9.522,and 0.309 pb,respectively,can be ***,to produce neutron-deficient isotopes of actinides near the proton drip line with Z=93−100,we attempted to generate the new isotopes(224−227Pu,228−232,237Cm)using the reactions ^(48)Ca+180,182,183 W and ^(48)Ca+^(184,186,187,192) *** maximum evaporation residue cross section values are 0.07,0.06,0.26,and 0.30 nb for the former set of reactions,and 1.96 pb,5.73 pb,12.16 pb,19.39 pb,54.79 pb,and 6.45 nb for the latter,*** results are expected to provide new information for the future synthesis of unknown neutron-deficient isotopes.

关键词： Dinuclear system(DNS)model Evaporation residue cross section Neutron-deficient isotopes

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Interpretation and characterization of rate of penetration intelligent prediction model

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Petroleum Science 2024年第1期21卷 582-596页

作者： Zhi-Jun Pei Xian-Zhi Song Hai-Tao Wang Yi-Qi shi Shou-Ceng tian Gen-Sheng li College of Petroleum Engineering China University of Petroleum(Beijing)Beijing102249China State Key Laboratory of Petroleum Resources and Prospecting Beijing102249China Kunlun Digital Technology Co. Ltd.Beijing102206China

Accurate prediction of the rate of penetration(ROP)is significant for drilling *** the intelligent ROP prediction model based on fully connected neural networks(FNN)outperforms traditional ROP equations and machine learning algorithms,its lack of interpretability undermines its *** study proposes a novel interpretation and characterization method for the FNN ROP prediction model using the Rectified linear Unit(ReLU)activation *** leveraging the derivative of the ReLU function,the FNN function calculation process is transformed into vector *** FNN model is linearly characterized through further simplification,enabling its interpretation and *** proposed method is applied in ROP prediction scenarios using drilling data from three vertical wells in the Tarim *** results demonstrate that the FNN ROP prediction model with ReLU as the activation function performs exceptionally *** relative activation frequency curve of hidden layer neurons aids in analyzing the overfitting of the FNN ROP model and determining drilling data *** the well sections with similar drilling data,averaging the weight parameters enables linear characterization of the FNN ROP prediction model,leading to the establishment of a corresponding linear representation ***,the quantitative analysis of each feature's influence on ROP facilitates the proposal of drilling parameter optimization schemes for the current well *** established linear characterization equation exhibits high precision,strong stability,and adaptability through the application and validation across multiple well sections.

关键词： Fully connected neural network Explainable artificial intelligence Rate of penetration ReLU active function Deep learning Machine learning

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