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Numerical simulation of pulsatile non-Newtonian flow in the carotid artery bifurcation

Acta Mechanica Sinica 2009年第2期25卷 249-255页

作者： Yubo Fan Wentao Jiang yuanwen zou Jinchuan Li Junkai Chen Xiaoyan Deng School of Biological Science and Medical Engineering Beihang University 100191 Beijing China Biomechanical Engineering Laboratory Sichuan University610065 Chengdu China

Both clinical and post mortem studies indicate that, in humans, the carotid sinus of the carotid artery bifurcation is one of the favored sites for the genesis and development of atherosclerotic lesions. Hemodynamic factors have been suggested to be important in atherogenesis. To understand the correlation between atherogenesis and fluid dynamics in the carotid sinus, the blood flow in artery was simulated numerically. In those studies, the property of blood was treated as an incompressible, Newtonian fluid. In fact, however, the blood is a complicated non-Newtonian fluid with shear thinning and viscoelastic properties, especially when the shear rate is low. A variety of non-Newtonian models have been applied in the numerical studies. Among them, the Casson equation was widely used. However, the Casson equation agrees well only when the shear rate is less than 10 s-1. The flow field of the carotid bifurcation usually covers a wide range of shear rate. We therefore believe that it may not be sufficient to describe the property of blood only using the Casson equation in the whole flow field of the carotid bifurcation. In the present study, three different blood constitutive models, namely, the Newtonian, the Casson and the hybrid fluid constitutive models were used in the flow simulation of the human carotid bifurcation. The results were compared among the three models. The results showed that the Newtonian model and the hybrid model had verysimilar distributions of the axial velocity, secondary flow and wall shear stress, but the Casson model resulted in significant differences in these distributions from the other two models. This study suggests that it is not appropriate to only use the Casson equation to simulate the whole flow field of the carotid bifurcation, and on the other hand, Newtonian fluid is a good approximation to blood for flow simulations in the carotid artery bifurcation.

关键词： Casson equation Hybrid fluid Newtonianfluid Carotid artery bifurcation

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人脸识别任务中角边距损失函数的对比研究

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智能计算机与应用 2024年第7期14卷 160-164页

作者：陈琳邹远文四川大学生物医学工程学院

深度卷积神经网络(DCNNs)和嵌入(Embedding)学习人脸特征是人脸识别任务的常用方法。在DCNNs网络中广泛使用Softmax损失函数，将欧几里得边距强加到DCNNs学习到的特征矩阵中，获得较好人脸识别正确率，但是仍具有较大的提高空间。近年... 详细信息

深度卷积神经网络(DCNNs)和嵌入(Embedding)学习人脸特征是人脸识别任务的常用方法。在DCNNs网络中广泛使用Softmax损失函数，将欧几里得边距强加到DCNNs学习到的特征矩阵中，获得较好人脸识别正确率，但是仍具有较大的提高空间。近年来提出的角边距损失函数进一步提升了人脸识别任务的正确率，但是人脸识别任务中角边距损失函数的对比研究较少，且缺乏在不同类别人脸数据集上对比角边距损失函数对人脸识别正确率的影响。本文使用MS1MV2数据集训练ResNet50模型，以Softmax损失函数为基准，对比研究ArcFace、CosFace、Combined Margin(CM)3种角边距损失函数在3个不同类别人脸数据集LFW、CFP-FP和AGEDB-30上的识别准确率，并调整角边距损失函数的参数值，讨论其对人脸识别任务性能的影响。实验结果表明，角边距损失函数较Softmax损失函数可以显著提升模型人脸识别正确率。在不同数据集和不同任务条件下，选择合适的角边距损失函数和参数设置可以提高人脸识别性能。

关键词：角边距损失函数人脸识别深度卷积神经网络

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Zirconium metal-organic framework nanocrystal as microwave sensitizer for enhancement of tumor therapy

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Chinese Chemical Letters 2019年第2期30卷 481-484页

作者： yuanwen zou Wei Zhang Hongqiao Zhou Changhui Fu Longfei Tan Zhongbing Huang Xiangling Ren Jun Ren Xudong Chen Xianwei Meng College of Materials Science and Engineering Sichuan University Second Clinical Medical College of Jinan University Shenzhen People's Hospital Laboratory of Controllable Preparation and Application of Nanomaterials CAS Key Laboratory of Cryogenics Technical Institute of Physics and Chemistry Chinese Academy of Sciences (CAS)

Although surgical resection and chemotherapy were widely applied in tumor therapy, the dysfunction of normal cells resulted in the side effects (such as anorexia, nausea). MW thermal therapy is a non-invasive anticancer strategy under the help of MW sensitizer, with the safety and higher efficacy. Zirconium metal-organic framework nanocubes (ZrMOF NCs) modified with polyethylene glycol, were prepared via one pot method and carbodiimide technique, resulting in their large specific surface area and porosity.Our results showed that non-ion-loaded ZrMOF NCs in 0.9% NaCl solution exhibited better heating effect,higher than that in pure water, due to the robust collision among the ions under MW irradiation. The in vivo experiments confirmed that ZrMOF-PEG NCs + MW group exhibited the higher temperature in the tumor region than that of only MW treatment, suggesting a better MW thermal therapeutic anticancer efficacy. This work provides a new preparation strategy of biosafety nanomaterial as MW sensitizer for enhancing MW thermal anticancer therapy.

关键词： Microwave thermal therapy Zirconium metal-organic framework nanocubes Microwave sensitizer Tumor therapy Biosafety

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Controlled release of dexamethasone from fibrin sealant for intratympanic administration in inner ear therapy

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Journal of Otology 2024年第1期19卷 55-58页

作者： Jing zou Department of Otolaryngology-Head and Neck Surgery Changhai HospitalSecond Military Medical UniversityShanghai200433China Faculty of Information Technology and Communication Sciences Tampere UniversityTampereFinland

The aim of the present work was to show the sustainability of fibrin sealant in releasing dexamethasone and adjust the protocol for clinical application of the novel method in the treatment of Meniere’s disease (MD) and sudden sensorineural hearing loss (SSHL).Gelation occurred shortly after mixing dexamethasone-containing fibrinogen with thrombin.Dexamethasone was constantly released for at least 16 d at a stable level after 7d in protocol 1 (low-dose),while it was robustly released within 4 d and slowed afterward until 10 d in protocol 2(high-dose).There were significant differences among the time points in Protocol 2 (p<0.01,ANOVA),and the exponential model with the formula y=15.299*e~(-0.483*t) fits the association.The estimated concentration of dexamethasone released on 7 d in protocol 2 was slightly lower than that observed in protocol 1.The fibrin sealant is capable of constantly releasing dexamethasone with adjustable dynamics.Targeted and minimally invasive administration of the material can be achieved in the clinic by sequential injections of the fluids using a soft-tipped catheter.

关键词： Intratympanic drug delivery Controlled release Corticosteroids Meniere's disease Sudden sensorineural hearing loss

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Conceptual transition from molecular to atomic: unleashing a new era in hydrogen therapy for chronic disease

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National Science Review 2024年第4期11卷 17-18页

作者： Zhigang zou Eco-materials and Renewable Energy Research Center (ERERC) Jiangsu Key Laboratory for Nano Technology National Laboratory of Solid State Microstructures and Department of PhysicsNanjing University

The dysregulated overexpression of reactive oxygen and nitrogen species (RONS)intricately links to the occurrence and development of diverse chronic diseases[1–3]. Hydrogen therapy stands out as a promising treatment methodology recognized for effectively mitigating RONS and maintaining intracellular redox equilibrium, thereby yielding therapeutic benefits [4,5].

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Westerhof阻力器计算阻值的一种校正方法

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生物医学工程学杂志 2017年第4期34卷 627-631页

作者：杨云姝邹远文四川大学材料科学与工程学院生物医学工程系成都610065

人体血液模拟循环系统(MCS)的目标是重现心血管血流动力学的特性。Westerhof阻力器在MCS中担任层流液阻器的角色,用来模拟心血管系统的外周阻力。Westerhof阻力器的理论计算结果较实际的液阻值有较大的误差,如果将理论公式计算的液阻值... 详细信息

人体血液模拟循环系统(MCS)的目标是重现心血管血流动力学的特性。Westerhof阻力器在MCS中担任层流液阻器的角色,用来模拟心血管系统的外周阻力。Westerhof阻力器的理论计算结果较实际的液阻值有较大的误差,如果将理论公式计算的液阻值当作实际的液阻值,那么精确度明显达不到设计目标和性能要求。为了减少阻力器液阻值理论计算结果与实际值之间的误差,本文提供了一种有效的Westerhof阻力器计算阻值的校正方法,并且开发了仿真模拟软件。仿真软件可以较为准确地预测毛细管数量、总长度、液阻值,降低和简化了设计阻力器的难度和复杂度,使得Westerhof阻力器制作更为精准,为各种循环模拟系统的构建提供了支持。

关键词：人体血液模拟循环系统 Westerhof阻力器泊肃叶方程阻值模拟仿真

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Security-Reliability Tradeoff Analysis for Jamming Aided Decode-and-Forward Relay Networks

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China Communications 2024年第5期21卷 218-228页

作者： zou Ronggui zou Yulong Zhu Jia Li Bin School of Telecommunications and Information Engineering Nanjing University of Posts and TelecommunicationsNanjing 210003China

In this paper,we explore a cooperative decode-and-forward(DF)relay network comprised of a source,a relay,and a destination in the presence of an eavesdropper.To improve physical-layer security of the relay system,we propose a jamming aided decodeand-forward relay(JDFR)scheme combining the use of artificial noise and DF relaying which requires two stages to transmit a packet.Specifically,in stage one,the source sends confidential message to the relay while the destination acts as a friendly jammer and transmits artificial noise to confound the eavesdropper.In stage two,the relay forwards its re-encoded message to the destination while the source emits artificial noise to confuse the eavesdropper.In addition,we analyze the security-reliability tradeoff(SRT)performance of the proposed JDFR scheme,where security and reliability are evaluated by deriving intercept probability(IP)and outage probability(OP),respectively.For the purpose of comparison,SRT of the traditional decode-and-forward relay(TDFR)scheme is also analyzed.Numerical results show that the SRT performance of the proposed JDFR scheme is better than that of the TDFR scheme.Also,it is shown that for the JDFR scheme,a better SRT performance can be obtained by the optimal power allocation(OPA)between the friendly jammer and user.

关键词： decode-and-forward relay friendly jammer physical layer security power allocation security-reliability tradeoff

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A pseudoclassical theory for the wavepacket dynamics of the kicked rotor model

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Science China(Physics,Mechanics & Astronomy) 2024年第3期67卷 34-43页

作者： Zhixing zou Jiao Wang Department of Physics and Key Laboratory of Low Dimensional Condensed Matter Physics(Department of Education of Fujian Province) Xiamen UniversityXiamen 361005China Lanzhou Center for Theoretical Physics Lanzhou UniversityLanzhou 730000China

In this study, we propose a generalized pseudoclassical theory for the kicked rotor model in an attempt to discern the footprints of the classical dynamics in the deep quantum regime. Compared with the previous pseudoclassical theory that applies only in the neighborhoods of the lowest two quantum resonances, the proposed theory is applicable in the neighborhoods of all quantum resonances in principle by considering the quantum effect of the free rotation at a quantum resonance. In particular, it is confirmed by simulations that the quantum wavepacket dynamics can be successfully forecasted based on the generalized pseudoclassical dynamics, offering an intriguing example where it is feasible to bridge the dynamics in the deep quantum regime to the classical dynamics. The application of the generalized pseudoclassical theory to the PT-symmetric kicked rotor is also discussed.

关键词： quantum-classical correspondence kicked rotor model pseudoclassical theory wavepacket dynamics

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Design of Robust Var Reserve Contract for Enhancing Reactive Power Ancillary Service Market Efficiency

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 767-771页

作者： Yunyang zou Yan Xu School of Electrical and Electronic Engineering Nanyang Technological UniversitySingapore 639798Singapore

In a deregulated Var market, market power issue is more serious than in an energy market since reactive power cannot be transmitted over long distances. This letter designs a multi-timescale Var market framework, where market power that may arise in the hourly-ahead Var support service market due to system configuration deficiency and market structure flaws can be eliminated by day-ahead contract-based Var reserve service market. Settlement of day-ahead Var reserve contract is formulated as a two-stage robust optimization (TSRO) model considering worst case of uncertainty realization and potential market power that may arise in hourly-ahead market. TSRO with integer recourses is then solved by a new column and constraint generation algorithm. Results show a robust Var reserve contract can fully eliminate market power, and prevent suppliers from manipulating market prices.

关键词： Market efficiency market power reactive power ancillary service two-stage robust optimization Var reserve

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Set-Membership Filtering Approach to Dynamic Event-Triggered Fault Estimation for a Class of Nonlinear Time-Varying Complex Networks

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IEEE/CAA Journal of Automatica Sinica 2024年第3期11卷 638-648页

作者： Xiaoting Du Lei zou Maiying Zhong the College of Electrical Engineering and Automation Shandong University of Science and TechnologyQingdao 266590China IEEE the College of Information Science and Technology Donghua UniversityShanghai 201620 the Engineering Research Center of Digitalized Textile and Fashion Technology Ministry of EducationShanghai 201620China

The present study addresses the problem of fault estimation for a specific class of nonlinear time-varying complex networks,utilizing an unknown-input-observer approach within the framework of dynamic event-triggered mechanism(DETM).In order to optimize communication resource utilization,the DETM is employed to determine whether the current measurement data should be transmitted to the estimator or not.To guarantee a satisfactory estimation performance for the fault signal,an unknown-input-observer-based estimator is constructed to decouple the estimation error dynamics from the influence of fault signals.The aim of this paper is to find the suitable estimator parameters under the effects of DETM such that both the state estimates and fault estimates are confined within two sets of closed ellipsoid domains.The techniques of recursive matrix inequality are applied to derive sufficient conditions for the existence of the desired estimator,ensuring that the specified performance requirements are met under certain conditions.Then,the estimator gains are derived by minimizing the ellipsoid domain in the sense of trace and a recursive estimator parameter design algorithm is then provided.Finally,a numerical example is conducted to demonstrate the effectiveness of the designed estimator.

关键词： Dynamic event-triggered mechanism(DETM) fault estimation nonlinear time-varying complex networks set-member-ship filtering unknown input observer

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