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Scattering correction method for panel detector based cone beam computed tomography system

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Chinese Physics B 2010年第8期19卷 609-613页

作者：贾鹏翔张峰闫镔包尚联 Beijing City Key Lab of Medical Physics and engineering Peking University China national Digital Switching System engineering and Technological research center

A scattering correction method for a panel detector based cone beam computed tomography system is presented. First, the x-ray spectrum of the system is acquired by using the Monte Carlo simulation method. Secondly, scattered photon distribution is calculated and stored as correction matrixes by using the Monte Carlo simulation method according to scanned objects and computed tomography system specialties. Thirdly, scattered photons are removed from projection data by correction matrixes. A comparison of reconstruction image between before and after scattering correction demonstrates that the scattering correction method is effective for the panel detector based cone beam computed tomography system.

关键词： scattering correction Monte Carlo simulation panel detector cone beam computed tomography system

Numerical simulation of aircraft arresting process with an efficient full-scale rigid-flexible coupling dynamic model

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Chinese Journal of Aeronautics 2024年第5期37卷 586-602页

作者： Haoyuan SHAO Daochun LI Zi KAN Lanxi BI Zhuoer YAO Jinwu XIANG School of Aeronautic Science and engineering Beihang UniversityBeijing 100191China Tianmushan Laboratory Hangzhou 310023China

The arresting process of carrier-based aircraft is widely recognized as a challenging task,characterized by the highest accident rate among all carrier-based aircraft *** simulation plays a crucial role in assessing the intricate responses of the arresting process,favoring the design of carrier-based *** efficient and accurate rigid-flexible coupling model for analyzing the dynamic response of the arresting process is *** combining the dynamic characteristics of airframe,landing gear,arresting hook and arresting gear system,the rigid-flexible coupling dynamic model is established to reflect the relative motion of the coupling parts and arresting *** dynamic model is verified through simulations of landing gear landing drops and by comparing the arresting simulation results with corresponding data in the US military ***,simulations of the arresting process under different off-center distance and aircraft yaw angle are conducted to obtain the dynamic response of the aircraft during the arresting *** result indicates that the rigid-flexible coupling dynamic model proposed is effective for analyzing the arresting dynamics response of carrier-based *** axial force of the arresting cable on both sides of the hook engagement point,pitch and yaw angle of aircraft are inconsistent under yaw and off-center *** analysis method and obtained results provide valuable references for assessing the dynamic responses of carrier-based aircraft during arresting process and offer valuable in-sights in the design of carrier-based aircraft.

关键词： Carrier-based aircraft Deck landing Rigid-flexible coupling dynamic model Finite element method Dynamic analysis

Microstructure and Oxidation Behavior of ZrB_(2)-SiC Ceramics Fabricated by Tape Casting and Reactive Melt Infiltration

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无机材料学报 2024年第8期39卷 955-964页

作者： TAN Min CHEN Xiaowu YANG Jinshan ZHANG Xiangyu KAN Yanmei ZHOU Haijun XUE Yudong DONG Shaoming State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China center of Materials Science and Optoelectronics engineering University of Chinese Academy of SciencesBeijing 100049China

ZrB_(2)-based ceramics typically necessitate high temperature and pressure for sintering,whereas ZrB_(2)-SiC ceramics can be fabricated at 1500℃using the process of reactive melt infiltration with *** comparison to the conventional preparation method,reactive synthesis allows for the more facile production of ultra-high temperature ceramics with fine particle size and homogeneous *** this work,ZrSi_(2),B4C,and C were used as raw materials to prepare ZrB_(2)-SiC via combination of tape casting and reactive melt infiltration herein referred to as ZBC *** sample of ZrB_(2)-SiC was also prepared using ZrB_(2) and SiC as raw materials through an identical process designated as ZS *** analysis of both ceramic groups revealed smaller and more uniformly distributed particles of the ZrB_(2) phase in ZBC ceramics compared to the larger particles in ZS *** sets of ceramics underwent cyclic oxidation testing in the air at 1600℃for a cumulative duration of 5 cycles,each cycle lasting 2 *** of the oxidation behavior showed that both ZBC ceramics and ZS ceramics developed a glassy SiO_(2)-ZrO_(2) oxide layer on their surfaces during the *** layer severed as a barrier against *** ZBC ceramics,ZrO_(2) is finely distributed in SiO_(2),whereas in ZS ceramics,larger ZrO_(2) particles coexist with glassy SiO_(2).The surface oxide layer of ZBC ceramics maintains a dense structure because the well-dispersed ZrO_(2) increases the viscosity of glassy SiO_(2),preventing its crystallization during the ***,some SiO_(2) in the oxide layer of ZS ceramics may crystallize and form a eutectic with ZrO_(2),leading to the formation of ZrSiO_(4).This leads to cracking of the oxide layer due to differences in thermal expansion coefficients,weakening its barrier *** analysis of the oxidation resistance shows that ZBC ceramics exhibit less increase in oxide layer thickness and mass compared to ZS ceramics,su

关键词： ultra-high temperature ceramic ZrB2-SiC oxidation behavior reactive melt infiltration

Metochalcone induces senescence-associated secretory phenotype via JAK2/STAT3 pathway in breast cancer

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Oncology research 2024年第5期32卷 943-953页

作者： JIANBO ZHOU FENG WAN BIN XIAO XIN LI CHENG PENG FU PENG Department of Pharmacology West China School of PharmacySichuan UniversityChengduChina State Key Laboratory of Southwestern Chinese Medicine Resources Chengdu University of Traditional Chinese MedicineChengduChina Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry Sichuan Engineering Laboratory for Plant-Sourced Drug and Sichuan Research Center for Drug Precision Industrial TechnologySichuan UniversityChengduChina Chengdu No.1 Pharmaceutical Co. Ltd.PengzhouChina Chengdu Push Bio-Technology Co. Ltd.ChengduChina

Breast and lung cancers are the leading causes of mortality and most frequently diagnosed cancers in women and men,respectively,*** the antitumor activity of chalcones has been extensively studied,the molecular mechanisms of isoliquiritigenin analog 2',4',4-trihydroxychalcone(metochalcone;TEC)against carcinomas remain less well *** this study,we found that TEC inhibited cell proliferation of breast cancer BT549 cells and lung cancer A549 cells in a concentration-dependent *** induced cell cycle arrest in the S-phase,cell migration inhibition in vitro,and reduced tumor growth in ***,transcriptomic analysis revealed that TEC modulated the activity of the JAK2/STAT3 and P53 *** triggered the senescence-associated secretory phenotype(SASP)by repressing the JAK2/STAT3 *** mechanism of metochalcone against breast cancer depended on the induction of SASP via deactivation of the JAK2/STAT3 pathway,highlighting the potential of chalcone in senescence-inducing therapy against carcinomas.

关键词： Metochalcone Breast cancer Lung cancer SASP JAK2/STAT3

Sampling efficiency of a polyurethane foam air sampler:Effect of temperature

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Environmental Science and Ecotechnology 2024年第2期18卷 43-52页

作者： Qiu-Liang Cai Cen-Yan Huang Lei Tong Ning Zhong Xiao-Rong Dai Jian-Rong Li Jie Zheng Meng-Meng He Hang Xiao Key Laboratory of Urban Environment and Health Ningbo Observation and Research StationInstitute of Urban EnvironmentChinese Academy of SciencesXiamen361021China Key Laboratory of Ecological Environment Analysis and Pollution Control in Western Guangxi Region College of Agriculture and Food EngineeringBaise UniversityBaise533000China College of Biological and Environmental Sciences Zhejiang Wanli UniversityNingbo315100China Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control CAS Haixi Industrial Technology Innovation Center in BeilunNingbo315830China Minnan Normal University Zhangzhou363000China

Effective monitoring of atmospheric concentrations is vital for assessing the Stockholm Convention's effectiveness on persistent organic pollutants(POPs).This task,particularly challenging in polar regions due to low air concentrations and temperature fluctuations,requires robust sampling ***,the influence of temperature on the sampling efficiency of polyurethane foam discs remains *** we employ a flow-through sampling(FTS)column coupled with an active pump to collect air samples at varying *** delved into breakthrough profiles of key pollutants,such as polycyclic aromatic hydrocarbons(PAHs),polychlorobiphenyls(PCBs),and organochlorine pesticides(OCPs),and examined the temperature-dependent behaviors of the theoretical plate number(N)and breakthrough volume(VB)using frontal chromatography *** findings reveal a significant relationship between temperature dependence coefficients(KTN,KTV)and compound volatility,with decreasing values as volatility *** distinct trends are noted for PAHs,PCBs,and OCPs in KTN,KTV values exhibit similar patterns across all ***,we establish a binary linear correlation between log(VB/m3),1/(T/K),and N,simplifying breakthrough level estimation by enabling easy conversion between N and ***,an empirical linear solvation energy relationship incorporating a temperature term is developed,yielding satisfactory results for N at various *** approach holds the potential to rectify temperature-related effects and loss rates in historical data from long-term monitoring networks,benefiting polar and remote regions.

关键词： Temperature Theoretical plate number Breakthrough volume Frontal chromatographic theory LSER

Vertical distribution characteristics of soil saturated hydraulic conductivity under different land use patterns in the Mu Us sandy land

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地球环境学报 2024年第4期15卷 665-674页

作者： LIU Xingting QIAO Jiangbo YANG Tao MA Yali TIAN Hanyang HAN Xiaoyang ZHU Yuanjun Institute of Soil and Water Conservation Northwest A&F UniversityYangling 712100China Shaanxi Academy of Forestry Xi’an 710082China engineering Technology research center for Amygdalus Pedunculata National Forestry and Grassland AdministrationYulin 719000China

Background,aim,and scope Soil saturated hydraulic conductivity(K_(s))is a key parameter in the hydrological cycle of soil;however,we have very limited understanding of K_(s)characteristics and the factors that inf luence this key parameter in the Mu Us sandy land(MUSL).Quantifying the impact of changes in land use in the Mu Us sandy land on K_(s)will provide a key foundation for understanding the regional water cycle,but will also provide a scientific basis for the governance of the *** and methods In this study,we determined K_(s)and the basic physical and chemical properties of soil(i.e.,organic matter,bulk density,and soil particle composition)within the first 100 cm layer of four different land use patterns(farmland,tree,shrub,and grassland)in the *** vertical variation of K_(s)and the factors that influence this key parameter were analyzed and a transfer function for estimating K_(s)was established based on a multiple stepwise regression *** The K_(s)of farmland,tree,and shrub increased gradually with soil depth while that of grassland remained *** K_(s)of the four patterns of land use were moderately variable;mean K_(s)values were ranked as follows:grassland(1.38 mm·min^(-1))research has shown that the K_(s)of farmland increases with soil *** root gro

关键词： Mu Us sandy land saturated hydraulic conductivity vertical distribution transfer function

Preparation and luminescence properties of Eu^(2+)-doped CASN-sinoite multiphase system for LED

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Journal of Rare Earths 2010年第S1期28卷 289-291页

作者：申颖庄卫东刘元红何华强何涛 national engineering research center for Rare Earth Materials Grirem Advanced Materials Co.Ltd.General Research Institute for Nonferrous Metals

A series of Eu2+-doped CASN-sinoite multiphase system with a formula of(CaAlSiN3)(1-x)-(Si2N2O)x were successfully synthesized by the high temperature solid-state *** crystal structure and morphology of the phosphors and their photoluminescence(PL) were *** the Eu2+-doped samples the PL intensity approached its maximum when the molar ratio of Si2N2O in the samples was about *** increase of the concentration of Si2N2O,the emission peak shifted from 645 to 605 *** was because the spectroscopic polarizability(αsp) became smaller with the increase of Si/Al ratio or the adding of O atoms,which caused the change of crystal field *** addition,the full width at half maximum(FWHM) widened with the increase of x value,which was favor of the improvement of the color rendering index.

关键词： LED CASN-sinoite multiphase system luminescence properties structure rare earths

Protein Corona Formation on Cadmium-Bearing Nanoparticles:Important Role of Facet-Dependent Binding of Cysteine-Rich Proteins

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Environment & Health 2024年第9期2卷 623-630页

作者： Yu Qi Wenyu Guan Chuanjia Jiang Wei Chen Tong Zhang State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085People’s Republic of China University of Chinese Academy of Sciences Beijing 100049People’s Republic of China College of Environmental Science and engineering Ministry of Education Key Laboratory of Pollution Processes and Environmental CriteriaTianjin Key Laboratory of Environmental Remediation and Pollution ControlNankai UniversityTianjin 300350People’s Republic of China

Cadmium-bearing nanoparticles,such as nanoparticulate cadmium selenide(CdSe)and cadmium sulfide(CdS),widely exist in the environment and originate from both natural and anthropogenic *** assessment of these nanoparticles cannot be accurate without taking into account the properties of the protein corona that is acquired by the nanoparticles upon ***,we show that the compositions of the protein corona on CdSe/CdS nanoparticles are regulated collectively by the surface atomic arrangement of the nanoparticles and the abundance and distribution of cysteine moieties of the proteins in contact with the nanoparticles.A proteomic analysis shows that the observed facet-dependent preferential binding of proteins is mostly related to the cysteine contents of the proteins,among commonly recognized protein properties controlling the formation of the protein *** calculations further demonstrate that the atomic arrangement of surface Cd atoms,as dictated by the exposed facets of the nanoparticles,controls the specific binding mode of the S atoms in the disulfide bonds of the *** protein adsorption experiments confirm that disulfide bonds remain intact during protein adsorption,making the binding of protein molecules sensitive to the abundance and distribution of Cd-binding moieties and possibly molecular rigidity of the *** significant conformational changes of adsorbed proteins evidenced from a circular dichroism spectroscopy analysis suggest that disrupting the structural stability of proteins may be an additional risk factor of Cd-bearing *** findings underline that the unique properties and behaviors of nanoparticles must be fully considered when evaluating the biological effects and health risks of metal pollutants.

关键词： Heavy metal Mineral nanoparticles Exposed facet Protein corona Preferential adsorption

Spatial Perception Reproduction of Sound Event Based on Sound Properties

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Wuhan University Journal of Natural Sciences 2015年第1期20卷 34-38页

作者： ZHANG Maosheng HU Ruimin CHEN Shihong WANG Xiaochen JIANG Lin WANG Heng national engineering research center for Multimedia Software Wuhan University

A new method for estimating gain factors in amplitude panning system is proposed. The method is based on particle ve- locity and balanced sound energy formulation. A scale factor is employed in amplitude panning system and thus, an overdeter- mined system of equation is derived in particle velocity equation. To obtain the analytic solution of the overdetermined equation, the sound energy identical formula is considered and then the unique gain factors are estimated. The proposed method is able to repro- duce sound source direction and control the distance perception in a flexible twoor three-dimension loudspeaker setup. Subjective evaluations show that the proposed technique in an aspheric loudspeaker setup maintains the sound direction and controls the distance perception at the listening point.

关键词： reproduction direction particle velocity perception