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Integration of Sequence Stratigraphic Analysis and 3D Geostatistical Modeling of Pliocene–Pleistocene Delta,F3 Block,Netherlands 被引量:1
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作者 Haris Ahmed KHAN Ali Asghar SHAHID +3 位作者 Muhammad Jahangir KHAN Taher ZOUAGHI Maria Dolores ALVAREZ Syed Danial Mehdi NAQVI 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2023年第1期256-268,共13页
This research is focused on the analysis of the sequence stratigraphic units of F3 Block,within a wave-dominated delta of Plio–Pleistocene age.Three wells of F3 block and a 3D seismic data,are utilized in this resear... This research is focused on the analysis of the sequence stratigraphic units of F3 Block,within a wave-dominated delta of Plio–Pleistocene age.Three wells of F3 block and a 3D seismic data,are utilized in this research.The conventional techniques of 3D seismic interpretation were utilized to mark the 11 surfaces on the seismic section.Integration of seismic sequence stratigraphic interpretation,using well logs,and subsequent 3D geostatistical modeling,using seismic data,aided to evaluate the shallow hydrocarbon traps.The resulting models were obtained using System Tract and Facies models,which were generated by using sequential stimulation method and their variograms made by spherical method,moreover,these models are validated via histograms.The CDF curve generated from upscaling of well logs using geometric method,shows a good relation with less percentage of errors(1 to 2 for Facies and 3 to 4 for System Tract models)between upscaled and raw data that complements the resulted models.These approaches help us to delineate the best possible reservoir,lateral extent of system tracts(LST and/or HST)in the respective surface,and distribution of sand and shale in the delta.The clinoform break points alteration observed on seismic sections,also validates the sequence stratigraphic interpretation.The GR log-based Facies model and sequence stratigraphy-based System Tract model of SU-04-2 showed the reservoir characteristics,presence of sand bodies and majorly LST,respectively,mainly adjacent to the main fault of the studied area.Moreover,on the seismic section,SU-04-2 exhibits the presence of gas pockets at the same location that also complements the generated Facies and System Tract models.The generated models can be utilized for any similar kind of study and for the further research in the F3 block reservoir characterization. 展开更多
关键词 sequence stratigraphy facies modeling system tract modeling f3 block North Sea
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基于生物动力学模型的^(18)F-FDGPET扫描患者个体化累积活度分布评估
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作者 何宇涛 倪明 +1 位作者 李晓宇 陈志 《中国医学物理学杂志》 CSCD 2024年第8期931-938,共8页
目的:利用生物动力学模型,在基于单个时间点PET图像的基础上,实现进行^(18)F-FDGPET扫描患者的个体化累积活度分布计算评估。方法:首先,构建目标器官的生物动力学隔室模型,并将各隔室内的活度变化描述为微分方程组。然后,使用每例患者... 目的:利用生物动力学模型,在基于单个时间点PET图像的基础上,实现进行^(18)F-FDGPET扫描患者的个体化累积活度分布计算评估。方法:首先,构建目标器官的生物动力学隔室模型,并将各隔室内的活度变化描述为微分方程组。然后,使用每例患者特定时间点的PET图像数据,采用模拟退火算法对模型系数进行优化,计算各个器官的累积活度情况,分析患者不同排尿情况下对膀胱累积活度的影响。最后,考虑放射性核素在组织器官中分布的异质性,计算人体全身累积活度分布图,并与现有方法进行对比,评估本研究提出方法的准确性。结果:在本研究分析的11例病例中,生物动力学模型的计算结果总体上与实验数据具有良好的一致性,平均差异小于15%。同时,在不同排尿情况下,患者膀胱的累积活度平均值差异最高可达2.4倍,表明强制患者排尿对于降低辐射影响有积极意义。与ICRP128号出版物中获得的生物动力学数据比较显示,脑部和心脏部分器官存在较大差异,标准偏差分别为61.0%和46.3%。结论:基于构建的生物动力学模型能够准确合理地计算PET患者个体化的累积活度分布,提出的评估方法将为进行PET扫描的每例患者的内照射辐射剂量学评估提供有价值的参考。 展开更多
关键词 ^(18)f-fDG 累积活度 生物动力学模型 内照射剂量
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双U/f下垂控制下双极MMC-HVDC系统交流阻抗建模及稳定性分析
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作者 李鹏坤 王跃 +3 位作者 冯伯乐 薛英林 刘熠 李润田 《电网技术》 EI CSCD 北大核心 2024年第3期1214-1223,共10页
基于模块化多电平换流器的高压柔性直流输电系统(modular multilevel converter-based high voltage direct current,MMC-HVDC)常采用双极接线方式以提高系统功率输送能力和可靠性。然而目前对于风电场经柔直外送系统的稳定性研究集中... 基于模块化多电平换流器的高压柔性直流输电系统(modular multilevel converter-based high voltage direct current,MMC-HVDC)常采用双极接线方式以提高系统功率输送能力和可靠性。然而目前对于风电场经柔直外送系统的稳定性研究集中于单极接线方式,孤岛直驱风电场与采用不同双极协调控制的双极MMC-HVDC互联系统小信号稳定性问题还有待进一步探究。该文首先考虑频率耦合特性、参考系初相位和直流侧耦合特性的影响,分别建立了采用双U/f下垂控制和定U/f-P/Q控制的双极MMC-HVDC系统交流侧等效SISO阻抗模型,并详细分析了金属回线阻抗和双极间功率均分度对交流阻抗特性的影响。接着对比研究了两种协调控制中共有控制环路和特有控制环路对交流侧负电阻特性及互联系统稳定性的影响规律。最后,孤岛直驱风电场经两种双极协调控制下双极MMC-HVDC外送系统Matlab/Simulink时域仿真结果和硬件在环半实物实时仿真实验结果验证了所提出的小信号阻抗模型的精确性和稳定性分析结论的有效性。 展开更多
关键词 模块化多电平换流器 孤岛直驱风电场 双极接线 双U/f下垂控制 定U/f-P/Q控制 阻抗建模 稳定性分析
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^(18)F-FDG PET/CT早期动态显像及建模在肺部疾病诊断和疗效评估中应用的研究进展
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作者 孙艺珊 辛军 《现代肿瘤医学》 CAS 2024年第19期3795-3800,共6页
^(18)F-FDG PET/CT早期动态显像描述了^(18)F-FDG自注射时间起在空间和时间上的分布,实时反映早期血流灌注和代谢情况,借助动态PET显像的动力学建模,用于脏器(或病灶组织)早期代谢的定量评估,可作为PET/CT常规全身静态显像的有益补充。... ^(18)F-FDG PET/CT早期动态显像描述了^(18)F-FDG自注射时间起在空间和时间上的分布,实时反映早期血流灌注和代谢情况,借助动态PET显像的动力学建模,用于脏器(或病灶组织)早期代谢的定量评估,可作为PET/CT常规全身静态显像的有益补充。该文将通过^(18)F-FDG PET/CT早期动态显像及建模在肺部疾病诊断和疗效评估中应用的研究进展对其进行系统阐述。 展开更多
关键词 正电子发射断层显像术 早期动态显像 ^(18)f-fDG 动力学模型
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基于工况分类的熟料f-CaO含量预测方法研究
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作者 崔保华 张成伟 +3 位作者 李慧霞 陈克政 郭文洁 孙战军 《水泥工程》 CAS 2024年第1期1-5,15,共6页
为实现游离氧化钙(f-CaO)含量的持续稳定预测,采用集成学习算法研究软测量实现方法。针对烧成系统中的复杂工况,首先展开工况分类,然后对每一类工况构建集成学习预测模型,同时引入在线建模的方式提高模型的泛化能力和时间有效性,解决了... 为实现游离氧化钙(f-CaO)含量的持续稳定预测,采用集成学习算法研究软测量实现方法。针对烧成系统中的复杂工况,首先展开工况分类,然后对每一类工况构建集成学习预测模型,同时引入在线建模的方式提高模型的泛化能力和时间有效性,解决了模型短期有效和重复性建模的问题。集成学习算法基于bagging的思想进行对多种弱学习器构建模型,通过检验发现模型效果显著优于单一模型效果。该算法融合了工艺生产特点和多种回归算法,具有较好的稳定性和提前性,实现了水泥质量的实时控制,助力水泥厂高质量稳定生产。 展开更多
关键词 f-CAO 集成学习 软测量 工况分类 在线建模
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基于长短期记忆网络的扩展F事件短临预测 被引量:1
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作者 孙树计 徐彤 +2 位作者 班盼盼 胡冉冉 陈春 《电波科学学报》 CSCD 北大核心 2023年第4期686-690,720,共6页
考虑到我国区域电离层扩展F发生的物理机制和相关因素以及观测数据的可获取性,利用适宜于时间序列预测的长短期记忆网络建立了我国不同区域电离层扩展F事件的预测模型,对未来3 h是否会发生扩展F事件进行预测.以处于我国典型纬度地区的... 考虑到我国区域电离层扩展F发生的物理机制和相关因素以及观测数据的可获取性,利用适宜于时间序列预测的长短期记忆网络建立了我国不同区域电离层扩展F事件的预测模型,对未来3 h是否会发生扩展F事件进行预测.以处于我国典型纬度地区的满洲里、北京、海口站为例,利用2015和2016年测试数据集对模型预测精度进行了检验,满洲里、北京、海口站平均准确率分别为92.4%、95.3%、96.0%,平均精确率分别为75.0%、61.2%、62.6%,平均召回率分别为73.0%、50.6%、31.5%.由此可见:在某些情况下,比如在低纬度地区的海口站,模型的召回率较低;除此之外,所建立的扩展F模型在多数情况下具有较高的预测能力. 展开更多
关键词 深度学习 扩展f 电离层 长短期记忆(LSTM)网络 预测模型
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Analysis of prompt fission neutron spectrum and multiplicity for ^(237)Np(n, f) in the frame of multi-modal Los Alamos model 被引量:1
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作者 郑娜 丁毅 +2 位作者 钟春来 陈金象 樊铁栓 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第4期1413-1420,共8页
The improved version of Los Alamos model with the multi-modal fission approach is used to analyse the prompt fission neutron spectrum and multiplicity for the neutron-induced fission of 237Np. The spectra of neutrons ... The improved version of Los Alamos model with the multi-modal fission approach is used to analyse the prompt fission neutron spectrum and multiplicity for the neutron-induced fission of 237Np. The spectra of neutrons emitted from fragments for the three most dominant fission modes (standard Ⅰ, standard Ⅱ and superlong) are calculated separately and the total spectrum is synthesized. The multi-modal parameters contained in the spectrum model are determined on the basis of experimental data of fission fragment mass distributions. The calculated total prompt fission neutron spectrum and multiplicity are better agreement with the experimental data than those obtained from the conventional treatment of the Los Alamos model. 展开更多
关键词 237Np(n f prompt neutron spectrum neutron multiplicity multi-modal model LosAlamos model
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Calculation of Prompt Fission Neutron from ^(233)U(n, f) Reaction byMulti-Modal Los Alamos Model 被引量:1
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作者 郑娜 钟春来 樊铁栓 《Plasma Science and Technology》 SCIE EI CAS CSCD 2012年第6期521-525,共5页
An attempt is made to improve the evaluation of the prompt fission neutron emis- sion from 233U(n, f) reaction for incident neutron energies below 6 MeV. The multi-modal fission approach is applied to the improved v... An attempt is made to improve the evaluation of the prompt fission neutron emis- sion from 233U(n, f) reaction for incident neutron energies below 6 MeV. The multi-modal fission approach is applied to the improved version of Los Alamos model and the point by point model. The prompt fission neutron spectra and the prompt fission neutron as a function of fragment mass (usually named "sawtooth" data) v(A) are calculated independently for the three most dominant fission modes (standard I, standard II and superlong), and the total spectra and v(A) are syn- thesized. The multi-modal parameters are determined on the basis of experimental data of fission fragment mass distributions. The present calculation results can describe the experimental data very well, and the proposed treatment is thus a useful tool for prompt fission neutron emission prediction. 展开更多
关键词 233U(n f prompt fission neutron multi-modal model Los Alamos model
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The 9L^(LUC)/Wistar rat glioma model is not suitable for immunotherapy 被引量:1
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作者 Liping Yang Jingxiang Zhao +6 位作者 Guihong Zhou Yunfang Wang Lusi Li Hongfeng Yuan Xue Nan Lidong Guan Xuetao Pei 《Neural Regeneration Research》 SCIE CAS CSCD 2012年第18期1406-1411,共6页
The availability of a well-characterized animal brain tumor model will play an important role in identifying treatments for human brain tumors. Wistar rats bearing 9L glioma cells can develop solid, well-circumcised t... The availability of a well-characterized animal brain tumor model will play an important role in identifying treatments for human brain tumors. Wistar rats bearing 9L glioma cells can develop solid, well-circumcised tumors, and may be a useful animal model for the evaluation of various therapeutic approaches for gliosarcomas. In this study, the 9L/Wistar rat glioma model was produced by intracerebral implantation of 9L^LUC glioma cells syngenic to Fischer 344 (F344) rats. Bioluminescence imaging showed that tumors progressively grew from day 7 to day 21 in 9L^LUC/F344 rats, and tumor regression was found in some 9L^LUC/Wistar rats. Hematoxylin-eosin staining verified that intracranial tumors were gliomas. Immunohistochemistry results demonstrated that no CD4- and CD8-positive cells were found in the syngeneic 9L^LUC/F344 model. However, many infiltrating CD4- and CD8-positive cells were observed within the tumors of the 9L^LUC/Wistar model. Our data suggests that compared with 9L/F344 rats, 9L glioma Wistar rats may not be suitable for evaluating brain glioma immunotherapies, even though the model induced an immune response and exhibited tumor regression. 展开更多
关键词 9L cells GLIOMA f344 rats Wistar rats animal model bioluminescence imaging immune response neural regeneration
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Cf/SiC复合材料铣削加工过程仿真分析及试验研究 被引量:1
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作者 吴逸宇 赵国龙 +4 位作者 李亮 毛东辰 雷梦勇 把圣伟 李晗 《机械制造与自动化》 2023年第2期77-80,100,共5页
针对Cf/SiC复合材料铣削加工过程中刀具磨损快、加工效率低、加工工艺优化试验成本高等问题,开展Cf/SiC复合材料三维铣削仿真分析及试验研究。基于ABAQUS软件建立Cf/SiC复合材料三维铣削加工仿真有限元模型,预测加工过程中的铣削力,通... 针对Cf/SiC复合材料铣削加工过程中刀具磨损快、加工效率低、加工工艺优化试验成本高等问题,开展Cf/SiC复合材料三维铣削仿真分析及试验研究。基于ABAQUS软件建立Cf/SiC复合材料三维铣削加工仿真有限元模型,预测加工过程中的铣削力,通过试验验证该模型的正确性。对比仿真预测的理论值和试验测得的实际值发现二者的平均误差仅为15%,所获取的一组较优的加工参数为Cf/SiC复合材料铣削加工参数优化提供了理论依据。 展开更多
关键词 Cf/SIC复合材料 铣削加工 有限元模型 参数优化
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Study on New Dynamical Model of Sequencing Batch Reactor (SBR) and Its Simulation
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作者 甘树应 刘振鸿 +1 位作者 杨青 陈季华 《Journal of China Textile University(English Edition)》 EI CAS 2000年第4期51-56,共6页
Sequencing Batch Reactor (SBR) was used for the wastewater treatment. A new dynamical model was put forward and developed. The substrate in influent was divided into soluble COD and insoluble COD. The soluble COD is f... Sequencing Batch Reactor (SBR) was used for the wastewater treatment. A new dynamical model was put forward and developed. The substrate in influent was divided into soluble COD and insoluble COD. The soluble COD is further subdivided into EBS, DBS and IOM. By dynamical simulation, many advantages appear in the new model. Furthermore, the proper ttf/tc, F/M and sludge age were suggested for the design and operation of SBR system. 展开更多
关键词 SBR DYNAMICAL SIMULATION model tfltc f/M SLUDGE age
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MRI-Based Patient-Specific Left Ventricular Model to Determine the Effects of Trabeculae Carneae on the Diastolic and Systolic Functions
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作者 Fatemeh Fatemifar Marc Feldman +2 位作者 Geoffrey Clarke Ender Finol Haichao Han 《医用生物力学》 EI CAS CSCD 北大核心 2019年第A01期19-20,共2页
Introduction Trabeculae carneae are irregular structures that cover the endocardial surfaces of both ventricles of human heart and account for a significant portion of the ventricular mass.However,the role of trabecul... Introduction Trabeculae carneae are irregular structures that cover the endocardial surfaces of both ventricles of human heart and account for a significant portion of the ventricular mass.However,the role of trabeculae carneae in left ventricular(LV)function is not well understood.Previous reports suggested that trabeculae help squeeze blood from the apical region during systole[1].Our recent study suggests that trabeculae carneae hypertrophy and fibrosis contribute to increased LV stiffness in patients with diastolic heart failure,and severing free-running trabeculae carneae may improve diastolic compliance of the LV[2].Objective To understand the role of trabeculae carneae in the left ventricular diastolic and systolic functions using anatomically detailed patient-specific finite element models of the human LV.Methods(1)Image acquisition An explanted human heart was collected from a 63 year old female donor with a history of stroke and congestive heart failure within 24 hours postmortem from South Texas Blood and Tissue Center(San Antonio,TX).The heart was de-identified in accordance with Institutional Review Board(IRB)requirements and informed consent for research was obtained from the donor’s family.Three-dimensional MRI scanning was conducted on a 3T(128 MHz)MRI system(TIM Trio,Siemens Medical Solutions),comprised of a superconducting magnet with a 60 cm diameter accessible bore,when the heart was submerged in a saline filled plastic container.(2)Finite element analysis Three distinct LV models were derived from the MR images.The first model was the intact trabeculated model(TM)which contained all trabeculae carneae and papillary muscles.This high-resolution anatomically detailed 3D model of the LV was segmented from 2D MR images in DICOM format using Mimics(Materialise NV,Leuven,Belgium).The second model was the papillary model(PM),in which the papillary muscles remain intact but most of the trabeculae carneae were excluded in the smoothing process.The third model was the smooth model(SM)in which the trabeculae carneae and papillary muscles were excluded during image segmentation.Finite element(FE)models of the TM,PM and SM were created by meshing 3D reconstructions of the acquired MR images using tetrahedral elements(ICEM,Ansys Inc.,Canonsburg,PA).The mesh size was selected after a pilot study on mesh sensitivity.The passive cardiac muscle was characterized as a hyperelastic,incompressible,transversely isotropic material with a Fung exponential strain energy function.The material constants were determined by matching the end-diastolic pressure-volume relationship with the empirical Klotz relation[3].A rule-based myocardial fiber algorithm was adopted to generate the myofiber directions [4].The active contraction(i.e.,systolic contraction)was modeled by the time varying'Elastance'active contraction model.The contractile parameter Tmax was determined and calibrated so that the FE predicted ejection fraction(EF)of TM matched the EF of a normal human heart at the specified end-systolic pressure[3].The analysis of the TM,PM,and SM models were implemented using the open-source finite element package FEBio(www.febio.org).In all models,the rigid body motion was suppressed by constraining the base from moving in all directions.The end-diastolic and end-systolic pressure-volume relationships(EDPVR and ESPVR)were obtained and characterized by an exponential function and the slope,respectively.Results Our simulation results showed that independent of the material model,the EDPVR curve shifts to the right in PM and SM compared to TM.However,the ESPVR curve may shift to the right or left in PM compared to TM,while shifting tothe right in SM for all material models.EDPVR was steeper in TM compared to PM and SM;however,ESPVR was found to be steeper in PM than in TM and SM.The predicted parameters of EDPVR and ESPVR showed lower average exponential term in PM and SM compared to TM,indicating a significant improvement in the compliance and global diastolic function of less trabeculated LV models(P<0.01).Similarly,the higher average elastance EEs and lower volume intersect in PM compared to TM,suggests that mild cutting of trabeculae carneae slightly improves the global systolic function of the LV(P=0.89).However,cutting all trabeculae carneae and papillary muscles in SM had a significant adverse effect on the global systolic function(P<0.01).Discussion and conclusions Most patient-specific LV studies in the literature have used smoothed ventricular geometries.We used high resolution MRI to capture the endocardial details of the LV.Though reproducing very fine trabeculae carneae was restricted by the MRI resolution,our results demonstrated the importance of considering endocardial structures,i.e.papillary muscles and trabeculae carneae,in the assessment of LV global function in patient-specific computational LV models.The present work is consistent with the observation that diastolic performance improved after severing trabeculae carneae due to a reduction in LV stiffness[2].Furthermore,our results also suggest that severing trabeculae carneae(without affecting papillary muscle)may improve LV systolic function.Our model results are consistent with experimental measurements using ex vivo rabbit heart perfusion [5].This improvement would be greater in hypertrophic hearts because trabeculae carneae are also hypertrophic and more fibrotic.Left ventricular hypertrophy is often associated with heart failure with preserved ejection fraction(HFpEF).There is no effective treatment for HFpEF,which is characterized by impaired diastolic relaxation due to increased LV stiffness.Our results indicate that trabecular cutting could be an effective treatment for HFpEF. 展开更多
关键词 Ef MRI-Based PATIENT-SPECIfIC TRABECULAE Carneae the DIASTOLIC and Systolic f model
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Stochastic Four-State Mechanochemical Model of F_1-ATPase
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作者 吴魏霞 展永 +2 位作者 赵同军 韩英荣 陈娅斐 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第10期630-634,共5页
F_1-ATPase, a part of ATP synthase, can synthesize and hydrolyze ATP moleculars in which the centralγ-subunit rotates inside the α_3β_3 cylinder.A stochastic four-state mechanochemical coupling model of F_1-ATPase ... F_1-ATPase, a part of ATP synthase, can synthesize and hydrolyze ATP moleculars in which the centralγ-subunit rotates inside the α_3β_3 cylinder.A stochastic four-state mechanochemical coupling model of F_1-ATPase isstudied with the aid of the master equation.In this model, the ATP hydrolysis and synthesis are dependent on ATP,ADP, and Pi concentrations.The effects of ATP concentration, ADP concentration, and the external torque on theoccupation probability of binding-state, the rotation rate and the diffusion coefficient of F_1-ATPase are investigated.Moreover, the results from this model are compared with experiments.The mechanochemical mechanism F_1-ATPase isqualitatively explained by the model. 展开更多
关键词 f1-ATPase four-state mechanochemical model hydrolysis reaction the master equation
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Thermal Modeling of a Multilayer Integrated LC Filter for Temperature Distribution Calculation
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作者 Somo Coulibaly Diby Kadjo Ambroise Loum Georges 《Engineering(科研)》 2019年第11期759-767,共9页
Thermal behavior of integrated passive components has become an important issue when designing these components. This paper presents the thermal modeling of a multilayer integrated LC filter used in DC-DC step-down co... Thermal behavior of integrated passive components has become an important issue when designing these components. This paper presents the thermal modeling of a multilayer integrated LC filter used in DC-DC step-down converter for temperature distribution calculation. The approach used for this analysis is based on thermal equivalent circuit. Temperature distribution is obtained from algebraic equation, which is in vector and matrix form. The results of analytical calculation are compared with simulation results from finite element method. These results showed a good correlation. 展开更多
关键词 THERMAL modeling INTEGRATED LC fILTER Temperature Distribution f. E. M. Simulation
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One extraction tool for in vitro-in vivo extrapolation?SPME-based metabolomics of in vitro 2D,3D,and in vivo mouse melanoma models
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作者 Karol Jaroch Paulina Taczynska +4 位作者 Marta Czechowska Joanna Bogusiewicz KamilŁuczykowski Katarzyna Burlikowska Barbara Bojko 《Journal of Pharmaceutical Analysis》 SCIE CAS CSCD 2021年第5期667-674,共8页
Solid phase microextraction(SPME)in combination with high-resolution mass spectrometry was employed for the determination of metabolomic profile of mouse melanoma growth within in vitro 2D,in vitro 3D,and in vivo mode... Solid phase microextraction(SPME)in combination with high-resolution mass spectrometry was employed for the determination of metabolomic profile of mouse melanoma growth within in vitro 2D,in vitro 3D,and in vivo models.Such multi-model approach had never been investigated before.Due to the low-invasiveness of SPME,it was possible to perform time-course analysis,which allowed building time profile of biochemical reactions in the studied material.Such approach does not require the multiplication of samples as subsequent analyses are performed from the very same cell culture or from the same individual.SPME already reduces the number of animals required for experiment;therefore,it is with good concordance with the 3Rs rule(replacement,reduction,and refinement).Among tested models,the largest number of compounds was found within the in vitro 2D cell culture model,while in vivo and in vitro 3D models had the lowest number of detected compounds.These results may be connected with a higher metabolic rate,as well as lower integrity of the in vitro 2D model compared to the in vitro 3D model resulting in a lower number of compounds released into medium in the latter model.In terms of in vitro-in vivo extrapolation,the in vitro 2D model performed more similar to in vivo model compared to in vitro 3D model;however,it might have been due to the fact that only compounds secreted to medium were investigated.Thus,in further experiments to obtain full metabolome information,the intraspheroidal assessment or spheroid dissociation would be necessary. 展开更多
关键词 Solid-phase microextraction In vitro-in vivo extrapolation Metabolomics MELANOMA B16f0 C57BL6 mouse model
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矩形顶管隧道F型承插接头抗弯性能试验研究
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作者 许有俊 庞跃魁 +3 位作者 张朝 聂绪致 张旭 刘天宇 《隧道建设(中英文)》 CSCD 北大核心 2023年第7期1099-1108,共10页
为研究矩形顶管隧道在地基沉降及上部荷载变化等情况下F型承插接头的抗弯性能、变形规律及破坏特征,在管节底部布置不同数量的等效地基弹簧来模拟不同地质条件,开展不同地层条件下的接头弯曲试验。试验结果表明:1)加载初期,接头弯曲变... 为研究矩形顶管隧道在地基沉降及上部荷载变化等情况下F型承插接头的抗弯性能、变形规律及破坏特征,在管节底部布置不同数量的等效地基弹簧来模拟不同地质条件,开展不同地层条件下的接头弯曲试验。试验结果表明:1)加载初期,接头弯曲变形主要为钢套环变形,各等效地基下接头抗弯刚度差异较小。2)当位移加载至15~25 mm时,管节顶底板内侧与侧墙外侧出现裂缝,由于管节自身变形使得接头张开量随着加载位移的增大出现减缓,接头抗弯刚度曲线斜率增大,并以0.007 rad张开量为界线划分为2个阶段。3)根据拉线式位移计变化、接头混凝土应变及钢套环应变可知,顶底板中部及侧墙中部挠曲应力最大,且在上方荷载作用下,管节表现出被压扁的趋势。4)接头弯曲变形中,插口端混凝土会与承口端混凝土及钢套环发生挤压,顶板混凝土被压碎,钢套环由于挤压而发生翘曲。 展开更多
关键词 矩形顶管 f型承插接头 模型试验 弯曲刚度 受力性能 变形特征
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A Model for the Sounding Rocket Measurement on an Ionospheric E-F Valley at the Hainan Low Latitude Station
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作者 王铮 史建魁 +4 位作者 关燚炳 刘超 朱光武 Klaus TORKAR Martin FREDRICH 《Plasma Science and Technology》 SCIE EI CAS CSCD 2014年第4期316-319,共4页
To understand the physics of an ionospheric E-F valley, a new overlapping three- Chapman-layer model is developed to interpret the sounding rocket measurement in the morn- ing (sunrise) on May 7, 2011 at the Hainan ... To understand the physics of an ionospheric E-F valley, a new overlapping three- Chapman-layer model is developed to interpret the sounding rocket measurement in the morn- ing (sunrise) on May 7, 2011 at the Hainan low latitude ionospheric observation station (19.5°N, 109.1°E). From our model, the valley width, depth and height are 43.0 km, 62.9% and 121.0 km, re- spectively. From the sounding rocket observation, the valley width, depth and height are 42.2 km, 47.0% and 123.5 km, respectively. The model results are well consistent with the sounding rocket observation. The observed E-F valley at Hainan station is very wide and deep, and rapid deel- opment of the photochemical process in the ionosphere should be the underlying reason. 展开更多
关键词 Chapman theory overlapping three-layer model ionospheric E-f valley
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计算宣传下基于F-V模型的社交机器人“5D”宣传策略研究——以战争情境中的推特文本为例
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作者 荣婷 孙佳倩 《新媒体与社会》 2023年第3期187-206,394,共21页
计算宣传时代,社交机器人在社交媒体舆论操纵与引导中的应用为国际宣传提供了新范式。本文以“契合度验证”模型(Fitness-Validation Model)和“5D”宣传策略为理论基础,选取推特中关于俄乌冲突的四个话题下的3506条社交机器人推文作为... 计算宣传时代,社交机器人在社交媒体舆论操纵与引导中的应用为国际宣传提供了新范式。本文以“契合度验证”模型(Fitness-Validation Model)和“5D”宣传策略为理论基础,选取推特中关于俄乌冲突的四个话题下的3506条社交机器人推文作为分析对象,研究发现俄乌双方的社交机器人为实现说服或劝阻的舆论干扰目的,采取了通过提示有利内容推动受众认同建构的误导(Deceive)策略、转移话题焦点促成态度契合的转移(Divert)策略、提供对冲信息引导新思维建构的中断(Disrupt)策略、调动感情共振促成态度认同的引诱(Decoy)策略以及通过强势提供信息以扰乱既有信息环境的干扰(Disturb)策略五种宣传策略类型。本研究通过透析冲突背景下社交机器人的宣传策略与规律,为我国把握新技术加持下的网络舆论战新形态、有效应对复杂严峻的国际舆论环境具有重要的前瞻意义。 展开更多
关键词 计算宣传 社交机器人 f-V模型 “5D”宣传策略
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F分数模型对房地产企业的适用性分析
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作者 郭素娟 《管理科学与研究(中英文版)》 2023年第11期56-61,共6页
当前房地产企业频频“暴雷”,如何保证现金流充足是相关企业亟待解决的问题。对企业的财务风险进行预警分析有助于提前发现企业经营中存在的问题,以促进其改善现金流情况。本研究首先分析了财务风险预警的概念,然后选取了房地产行业中2... 当前房地产企业频频“暴雷”,如何保证现金流充足是相关企业亟待解决的问题。对企业的财务风险进行预警分析有助于提前发现企业经营中存在的问题,以促进其改善现金流情况。本研究首先分析了财务风险预警的概念,然后选取了房地产行业中20家非ST(正常经营)企业和13家ST(非正常经营)企业的2020-2022年的相关财务指标作为分析基础,运用F分数模型分别计算其F值,然后根据其结果计算得出该模型运用在房地产行业中的预警效果。最终发现,F分数模型对于预测我国房地产行业的企业财务风险具有一定的实践价值,并对房地产企业进行财务风险预警提出建议。 展开更多
关键词 财务风险预警 f分数模型 房地产企业
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黄河流域水-能源-粮食纽带系统效率研究
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作者 高建刚 刘津澔 +1 位作者 徐凯 何丽娜 《人民黄河》 CAS 北大核心 2024年第10期67-71,共5页
为了促进黄河流域高质量发展,考察黄河流域水-能源-粮食(W-E-F)纽带系统效率及其影响因素,并从中探寻提高系统效率的途径。首先借助三阶段DEA模型测算2005—2021年黄河流域及各省(区)W-E-F纽带系统效率,其次对黄河流域整体及各省(区)效... 为了促进黄河流域高质量发展,考察黄河流域水-能源-粮食(W-E-F)纽带系统效率及其影响因素,并从中探寻提高系统效率的途径。首先借助三阶段DEA模型测算2005—2021年黄河流域及各省(区)W-E-F纽带系统效率,其次对黄河流域整体及各省(区)效率测算结果进行时空分析,最后使用双向固定效应模型实证考察W-E-F纽带系统效率的影响因素。研究表明:1)黄河流域整体W-E-F纽带系统效率呈现波动上升趋势,并呈现上、中、下游效率依次上升的空间分布格局;2)黄河流域各省(区)具备一定的资源配置能力,第三阶段规模效率有所下降;3)粮食安全、能源安全、环保支出、研发投入以及人均GDP都对W-E-F纽带系统效率起到显著的正向促进作用。 展开更多
关键词 水-能源-粮食纽带系统 W-E-f纽带系统效率 三阶段DEA模型 黄河流域
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