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A STABILIZED EQUAL-ORDER FINITE VOLUME METHOD FOR THE STOKES EQUATIONS

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Journal of Computational Mathematics 2012年第6期30卷 615-628页

作者： wanfu tian Liqiu Song Yonghai Li School of Science Shenyang Aerospace University Shenyang 110136 China Institute of Mathematics Jilin University Changchun 130012 China School of Mathematics Jilin University Changchun 130012 China

We construct a new stabilized finite volume method on rectangular grids for the Stokes equations. The lowest equal-order conforming finite element pair （piecewise bilinear veloc- ities and pressures） and piecewise constant test spaces for both the velocity and pressure are employed in this method. We show the stability of this method and prove first optimal rate of convergence for the velocity in the H1 norm and the pressure in the L2 norm. In addition, a second order optimal error estimate for the velocity in the L2 norm is derived. Numerical experiments illustrating the theoretical results are included.

关键词： Stokes equations Equal-order finite element pair Finite volume method Errorestimate.

A Finite Volume Method Based on the Constrained Nonconforming Rotated Q_(1)-Constant Element for the Stokes Problem

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Advances in Applied Mathematics and Mechanics 2012年第1期4卷 46-71页

作者： Jing Qi wanfu tian Yonghai Li Jilin University Changchun 130012China School of Mathematics Jilin UniversityChangchun 130012China School of Science Shenyang Aerospace UniversityShenyang 110136China

We construct a finite volume element method based on the constrained nonconforming rotated Q_(1)-constant element(CNRQ_(1)-P_(0))for the Stokes *** meshes are needed,which are the primal mesh and the dual *** approximate the velocity by CNRQ_(1)elements and the pressure by piecewise *** errors for the velocity in the H^(1)norm and for the pressure in the L^(2)norm are O(h)and the error for the velocity in the L^(2)norm is O(h^(2)).Numerical experiments are presented to support our theoretical results.

关键词： Stokes problem finite volume method constrained nonconforming rotated Q_(1)element

Rotordynamic characteristics prediction for scallop damper seals using computational fluid dynamics

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Chinese Journal of Aeronautics 2022年第8期35卷 92-106页

作者： wanfu ZHANG Lu YIN Li YANG Haoyang tian Chun LI School of Energy and Power Engineering University of Shanghai for Science and TechnologyShanghai 200093China Electric Power Research Institute of State Grid Shanghai Municipal Electric Power CompanyShanghai 200437China

Enhancing damping characteristic is one of the effective methods to solve the instability problem of the rotor *** three-dimensional numerical analysis model of scallop damper seal was established,and the effects of inlet pressures,preswirl ratios,rotational speeds,interlaced angles and seal cavity depths on the rotordynamic characteristics of scallop damper seal were studied based on dynamic mesh method and multi-frequencies elliptic whirling *** show that the direct stiffness of the scallop damper seal increases with decreasing inlet pressure and increasing rotational speed and cavity *** the seal cavity is interlaced by a certain angle,which shows positive direct *** effective damping of the scallop damper seal increases with the increasing inlet pressure,the decreasing preswirl ratio and the rotational speed and cavity *** exists an optimal interlaced angle to maximize the effective damping and the system *** leakage of the scallop damper seal is significantly reduced with decreasing inlet *** preswirl will reduce the leakage flowrate,and the rotational speed has a slight effect on the leakage *** leakage of the scallop damper seal decreases with increasing seal cavity depth.

关键词： Computational Fluid Dynamics(CFD) Effective damping Rotordynamic characteristics Scallop damper seal Stability

广义Nekrasov矩阵的一组改进的判别条件

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数值计算与计算机应用 2022年第3期43卷 307-313页

作者：吕振华孙旭田万福温立书沈阳航空航天大学理学院沈阳110136

综合运用细节分析、指标集划分以及不等式的放缩技巧,给出了广义Nekrasov矩阵的新的判定方法,推广了郭爱丽、刘建州2009年和2016年提出的相关结论,并利用数值算例说明了判定条件的有效性.这样的改进思路同样适用于其他的广义Nekrasov矩... 详细信息

综合运用细节分析、指标集划分以及不等式的放缩技巧,给出了广义Nekrasov矩阵的新的判定方法,推广了郭爱丽、刘建州2009年和2016年提出的相关结论,并利用数值算例说明了判定条件的有效性.这样的改进思路同样适用于其他的广义Nekrasov矩阵的判定方法的改进.

关键词：广义Nekrasov矩阵 Nekrasov矩阵若Nekrasov矩阵非奇异H-矩阵特殊矩阵

Research status and prospects of the fractal analysis of metal material surfaces and interfaces

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International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 20-38页

作者： Qinjin Dai Xuefeng Liu Xin Ma Shaojie tian Qinghe Cui Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing 100083China Beijing Laboratory of Metallic Materials and Processing for Modern Transportation University of Science and Technology BeijingBeijing 100083China Laboratory for Advanced Materials Processing of Ministry of Education University of Science and Technology BeijingBeijing 100083China School of Mechanical and Electrical Engineering Xinjiang Institute of EngineeringUrumqi 830023China

As a mathematical analysis method,fractal analysis can be used to quantitatively describe irregular shapes with self-similar or self-affine *** analysis has been used to characterize the shapes of metal materials at various scales and *** methods make it difficult to quantitatively describe the relationship between the regular characteristics and properties of metal material surfaces and ***,fractal analysis can be used to quantitatively describe the shape characteristics of metal materials and to establish the quantitative relationships between the shape characteristics and various properties of metal *** the perspective of two-dimensional planes and three-dimensional curved surfaces,this paper reviews the current research status of the fractal analysis of metal precipitate interfaces,metal grain boundary interfaces,metal-deposited film surfaces,metal fracture surfaces,metal machined surfaces,and metal wear *** relationship between the fractal dimensions and properties of metal material surfaces and interfaces is *** from three perspectives of fractal analysis,namely,research scope,image acquisition methods,and calculation methods,this paper identifies the direction of research on fractal analysis of metal material surfaces and interfaces that need to be *** is believed that revealing the deep influence mechanism between the fractal dimensions and properties of metal material surfaces and interfaces will be the key research direction of the fractal analysis of metal materials in the future.

关键词： metal material surfaces and interfaces fractal analysis fractal dimension homogeneity

Nanocarrier-mediated siRNA delivery:a new approach for the treatment of traumatic brain injury-related Alzheimer's disease

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Neural Regeneration Research 2025年第9期20卷 2538-2555页

作者： Jie Jin Huajing Zhang Qianying Lu Linqiang tian Sanqiao Yao Feng Lai Yangfan Liang Chuanchuan Liu Yujia Lu Sijia tian Yanmei Zhao Wenjie Ren Institute of Disaster and Emergency Medicine Tianjin UniversityTianjinChina Key Laboratory for Disaster Medicine Technology TianjinChina Henan Medical Key Laboratory for Research of Trauma and Orthopedics The Third Affiliated Hospital of Xinxiang Medical UniversityXinxiangHenan ProvinceChina Clinical Medical Center of Tissue Engineering and Regeneration Xinxiang Medical UniversityXinxiangHenan ProvinceChina Institutes of Health Central Plain Xinxiang Medical UniversityXinxiangHenan ProvinceChina School of Public Health Xinxiang Medical UniversityXinxiangHenan ProvinceChina

Traumatic brain injury and Alzheimer's disease share pathological similarities,including neuronal loss,amyloid-βdeposition,tau hyperphosphorylation,blood-brain barrier dysfunction,neuroinflammation,and cognitive ***,traumatic brain injury can exacerbate Alzheimer's disease-like pathologies,potentially leading to the development of Alzheimer's *** offer a potential solution by facilitating the delive ry of small interfering RNAs across the blood-brain barrier for the targeted silencing of key pathological genes implicated in traumatic brain injury and Alzheimer's disease.U nlike traditional approaches to neuro regeneration,this is a molecula r-targeted strategy,thus avoiding non-specific drug *** review focuses on the use of nanocarrier systems for the efficient and precise delive ry of siRNAs,discussing the advantages,challenges,and future *** principle,siRNAs have the potential to target all genes and non-targetable protein s,holding significant promise for treating various *** the various therapeutic approaches currently available for neurological diseases,siRNA gene silencing can precisely"turn off"the expression of any gene at the genetic level,thus radically inhibiting disease progression;however,a significant challenge lies in delivering siRNAs across the blood-brain *** have received increasing attention as an innovative drug delive ry tool fo r the treatment of brain *** are considered a potential therapeutic strategy with the advantages of being able to cross the blood-brain barrier,targeted drug delivery,enhanced drug stability,and multifunctional *** use of nanoparticles to deliver specific modified siRNAs to the injured brain is gradually being recognized as a feasible and effective *** this strategy is still in the preclinical exploration stage,it is expected to achieve clinical translation in the future,creating a new field of molecular tar

关键词： blood-brain barrier cognitive dysfunction exosomes gene silencing immunotherapy inorganic nanomaterials liposome nanoparticles neuroinflammation polymer nanoparticles stem cells

Coagulation indices and fibrinogen degradation products as predictive biomarkers for tumor-node-metastasis staging and metastasis in gastric cancer

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World Journal of Gastrointestinal Oncology 2025年第1期17卷 110-120页

作者： Yi-Qing Shen Qiu-Wan Wei Yi-Ren tian Yun-Zhi Ling Min Zhang Clinical Laboratory Civil Aviation Shanghai HospitalGubei Branch of Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of MedicineShanghai 200000China Clinical Laboratory Tongji Hospital of Tongji UniversityShanghai 200000China

BACKGROUND Gastric cancer(GC)is a prevalent malignancy with a substantial health burden and high mortality rate,despite advances in prevention,early detection,and *** with the global average,Asia,notably China,reports disproportionately high GC *** disease often progresses asymptoma-tically in the early stages,leading to delayed diagnosis and compromised ***,it is crucial to identify early diagnostic biomarkers and enhance treatment strategies to improve patient outcomes and reduce *** Retrospectively analyzed the clinical data of 148 patients with GC treated at the Civil Aviation Shanghai Hospital between December 2022 and December *** associations of coagulation indices-partial thromboplastin time(APTT),prothrombin time(PT),thrombin time(TT),fibrinogen,fibrinogen degradation products(FDP),fasting blood glucose,and D-dimer(D-D)with TNM stage and distant metastasis were *** Prolongation of APTT,PT,and TT was significantly correlated with the GC TNM ***,abnormal coagulation system activation was closely related to disease *** FDP and D-D were significantly associated with distant metastasis in GC(P<0.05),suggesting that increased fibrinolytic activity contributes to increased metastatic *** Our Results reveal coagulation indices,FDPs as GC biomarkers,reflecting abnormal coagulation/fibrinolysis,aiding disease progression,metastasis prediction,and helping clinicians assess thrombotic risk for early intervention and personalized treatment plans.

关键词： Coagulation indexes Fibrinogen degradation products Gastric cancer Tumor-node-metastasis staging Distant metastasis

Obesity paradox in patients with community-acquired pneumonia:Have you fully considered the confounding factors?

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World Journal of Clinical Cases 2025年第9期13卷 53-55页

作者： Jin-Ke Sun Hui tian Department of Pulmonary and Critical Care Medicine Affiliated Hospital of Shandong University of Traditional Chinese MedicineJinan 250000Shandong ProvinceChina Department of Critical Care Medicine Liaocheng People’s HospitalLiaocheng 252000Shandong ProvinceChina

There exists a notion that there is an obesity paradox in the prognosis of community-acquired *** other words,obese individuals with communityacquired pneumonia have a better *** study by Wang et al supports this claim,but we believe that the obesity paradox should not be proposed hastily as it is influenced by numerous subjective and objective confounding factors.

关键词： Community-acquired pneumonia Mortality Body mass index Overweight Obesity paradox

Ultra‑High Sensitivity Anisotropic Piezoelectric Sensors for Structural Health Monitoring and Robotic Perception

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Nano-Micro Letters 2025年第2期17卷 432-446页

作者： Hao Yin Yanting Li Zhiying tian Qichao Li Chenhui Jiang Enfu Liang Yiping Guo State Key Laboratory of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240People’s Republic of China Beijing Vacuum Electronics Research Institute Beijing 100015People’s Republic of China Fundamental Science On Vibration Shock and Noise LaboratoryState Key Laboratory of Mechanical System and VibrationSchool of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240People’s Republic of China

Monitoring minuscule mechanical signals,both in magnitude and direction,is imperative in many application scenarios,e.g.,structural health monitoring and robotic sensing ***,the piezoelectric sensor struggles to satisfy the requirements for directional recognition due to the limited piezoelectric coefficient matrix,and achieving sensitivity for detecting micrometer-scale deformations is also ***,we develop a vector sensor composed of lead zirconate titanate-electronic grade glass fiber composite filaments with oriented arrangement,capable of detecting minute anisotropic *** as-prepared vector sensor can identify the deformation directions even when subjected to an unprecedented nominal strain of 0.06%,thereby enabling its utility in accurately discerning the 5μm-height wrinkles in thin films and in monitoring human pulse *** ultra-high sensitivity is attributed to the formation of porous ferroelectret and the efficient load transfer efficiency of continuous lead zirconate titanate ***,when integrated with machine learning techniques,the sensor’s capability to recognize multi-signals enables it to differentiate between 10 types of fine textures with 100%*** structural design in piezoelectric devices enables a more comprehensive perception of mechanical stimuli,offering a novel perspective for enhancing recognition accuracy.

关键词： Flexible piezoelectric filaments Anisotropic Ultra-high sensitivity Structural health detection Texture recognition