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New insights into hydraulic fracturing fluids used for hightemperature wells

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Petroleum 2021年第1期7卷 70-79页

作者： Tariq Almubarak Leiming li Jun Hong ng Hisham Nasr-El-Din Mohammed AlKhaldi Texas A&M University USA Aramco Services Company Saudi Arabia Saudi Aramco EXPEC ARC Saudi Arabia

Current interest in deep,low-permeability formations(<10 md)demands accelerated development of high-temperature hydraulic fracturing *** guar systems break down above 300°F and require higher polymer loadings to main... 详细信息

Current interest in deep,low-permeability formations(ydraulic fracturing *** guar systems break down above 300°F and require higher polymer loadings to maintain thermal ***,higher polymer loadings generate more residue and damage to the proppant pack and the *** resolve these problems,a variety of high-temperature stabilizers are added to enhance the thermal stability of these fracturing fluids at temperatures above 300*** focus of this work is to:(1)identify those additives that best enhance temperature stability of fracturing fluids and(2)study the rheological influence of incorporating these additives on the fracturing fluid *** experimental fracturing-fluid solutions were prepared at a total polymer concentration of 30 and 40 lb/1000 *** such as synthetic polymer,oxygen scavengers,crosslinkers,crosslinker delay additives,and pH buffers were examined in this *** polymer solutions were crosslinked with a metallic crosslinker between 200 and 400°*** measurements were carried out in a highpressure/high-temperature(HP/HT)rheometer to evaluate rheology and thermal *** show that adding a synthetic polymer and a crosslinker with the slowest reaction rate improves the fracturing fluid thermal *** the three other additives tested,oxygen scavengers showed the greatest enhancement to thermal stability while pH buffers showed the *** the addition of high-temperature stabilizing additives,the fracturing fluid in this work was able to maintain a stable performance at temperatures up to 400°*** the thermal stability of fracturing fluids at a lower polymer loading remains a challenge in the *** work proposes techniques that can be used to enhance the thermal stability of fracturing *** knowledge about these different techniques will allow for better additive development and a

关键词： Oxygen scavenger Crosslinker Crosslinker delay Shear tolerance High temperature Synthetic polymer CMHPG Buffers

Multi-relaxation-time lattice Boltzmann simulations of lid driven flows using graphics processing unit

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Applied Mathematics and Mechanics(English Edition) 2017年第5期38卷 707-722页

作者： Chenggong li J.P.y.MAA National Engineering Laboratory for Methanol to Olefins Dalian National Laboratory for Clean EnergyDalian Institute of Chemical PhysicsChinese Academy of Sciences College of William and Mary Virginia Institute of Marine Science

Large eddy simulation （LES） using the Smagorinsky eddy viscosity model is added to the two-dimensional nine velocity components （D2Q9） lattice Boltzmann equation （LBE） with multi-relaxation-time （MRT） to simulate incompressible turbulent cavity flows with the Reynolds numbers up to 1 × 10^7. To improve the computation efficiency of LBM on the numerical simulations of turbulent flows, the massively parallel computing power from a graphic processing unit （GPU） with a computing unified device architecture （CUDA） is introduced into the MRT-LBE-LES model. The model performs well, compared with the results from others, with an increase of 76 times in computation efficiency. It appears that the higher the Reynolds numbers is, the smaller the Smagorinsky constant should be, if the lattice number is fixed. Also, for a selected high Reynolds number and a selected proper Smagorinsky constant, there is a minimum requirement for the lattice number so that the Smagorinsky eddy viscosity will not be excessively large.

关键词： large eddy simulation (LES) multi-relaxation-time (MRT) lattice Boltzmann equation (LBE) two-dimensional nine velocity components (D2Q9) Smagorinskymodel graphic processing unit (GPU) computing unified device architecture (CUDA)

Intratumoral Bacteria Dysbiosis Is Associated with Human Papillary Thyroid Cancer and Correlated with Oncogenic Signaling Pathways

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Engineering 2023年第9期28卷 179-192页

作者： Shuang yu yanqiang Ding Xuejie Wang Siu Kin ng Siting Cao Weixin liu Zhuming Guo yubin Xie Shubin Hong lixia Xu Xiaoxing li Jie li Weiming Lv Sui Peng yanbing li Joseph J.y.Sung Jun yu Haipeng Xiao Department of Endocrinology The First Affiliated Hospital of Sun Yat-Sen UniversityGuangzhou 510080China Institute of Digestive Disease and Department of Medicine and Therapeutics State Key Laboratory of Digestive DiseaseThe Chinese University of Hong KongHong Kong 999077China Department of Head and Neck Surgery Sun Yat-Sen University Cancer CenterGuangzhou 510060China Clinical Trials Unit The First Affiliated Hospital of Sun Yat-Sen UniversityGuangzhou 510080China Institute of Precision Medicine The First Affiliated Hospital of Sun Yat-Sen UniversityGuangzhou 510080China Department of Oncology The First Affiliated Hospital of Sun Yat-Sen UniversityGuangzhou 510080China Department of Breast and Thyroid Surgery The First Affiliated Hospital of Sun Yat-Sen UniversityGuangzhou 510080China Lee Kong Chian School of Medicine Nanyang Technology UniversitySingapore 308232Singapore

Emerging evidence suggests that microbial dysbiosis plays vital roles in many human ***,knowledge of whether the microbial community in thyroid tumor is related to tumorigenesis remains *** this study,we aimed to explore the microbial community in thyroid tissues and its contribution to papillary thyroid cancer(PTC).In parallel,we performed microbial profiling and transcriptome sequencing in the tumor and adjacent normal tissues of a large cohort of 340 PTC and benign thyroid nodule(BTN)*** microbial signatures were identified in PTC,BTN,and their adjacent nontumor ***-thyroid tissue bacteria were verified by means of bacteria staining,fluorescence in situ hybridization,and immunoelectron *** found that 17 bacterial taxa were differentially abundant in PTC compared with BTN,which included enrichment in PTC of the pathobionts Rhodococcus,Neisseria,Streptococcus,Halomonas,and Devosia,and depletion of the beneficial bacteria *** differentially abundant bacteria could differentiate PTC tumor tissues(PTC-T)from BTN tissues(BTN-T)with an area under the curve(AUC)of 81.66%.Microbial network analysis showed increased correlation strengths among the bacterial taxa in PTC-T in comparison with ***-corresponding bacteria(i.e.,Erwinia,Bacillus,and Acinetobacter)were found to be enriched in PTC with Hashimoto’s ***,our integrative analysis revealed that the PTC-enriched bacteria had a positive association with key PTC-oncogenic pathway-related genes,including BRAF,KRAS,IRAK4,CTNNB1,PIK3CA,MAP3K7,and *** conclusion,our results suggest that intratumor bacteria dysbiosis is associated with the thyroid tumorigenesis and oncogenic signaling pathways of PTC.

关键词： Papillary thyroid cancer Benign thyroid nodule Bacteria Transcriptome Hashimoto’s thyroiditis

Mobile technology:Usage and perspective of patients and caregivers presenting to a tertiary care emergency department

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World Journal of Emergency Medicine 2020年第1期11卷 5-11页

作者： Zhenghong liu Mingwei ng Dinesh V.Gunasekeran Huihua li Kishanti Ponampalam R Ponampalam SingHealth Emergency Medicine Residency Programme Singapore Health ServicesSingapore Ministry of Health Holdings Singapore Health Services Research Unit Singapore General HospitalSingapore University of Newcastle Australia Department of Emergency Medicine Singapore General HospitalSingapore

BACKGROUND:Developments in information technology(IT)have driven a push in healthcare innovation in the emergency department(ED).Many of these applications rely on mobile technology(MT)such as smartphones but not everyone is comfortable with MT *** study aims to characterize the technology usage behavior of users in the ED so as to guide the implementation of IT interventions in the ***:A cross-sectional survey was conducted in the emergency department of a tertiary *** and their caregivers aged 21 and above were *** survey collected demographic information,technology usage patterns,and participant reported comfort level in the usage of *** performed descriptive statistics and multivariate logistic regression to identify factors differentially associated with comfort in usage of ***:A total of 498 participants were recruited,and 299(60%)were *** was the most commonly written and read language(66.9%)and 64.2%reported a comfort level of 3/5 or more in using *** that were associated with being comfortable in using MT include having a tertiary education,being able to read and write English,as well as being a frequent user of *** were more likely to display these ***:A large proportion of ED patients are not comfortable in the usage of *** that predicted comfort level in the usage of MT were common amongst *** interventions should take this into consideration in the design of MT interventions.

关键词： Mobile health technology Information technology Emergency department

In vitro Study on Biodegradable AZ31 Magnesium Alloy Fibers Reinforced PLGA Composite

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Journal of Materials Science & Technology 2013年第6期29卷 545-550页

作者： y.H.Wu N.li y.Cheng y.F.Zheng y.Han Center for Biomedical Materials and Tissue Engineering Academy for Advanced Interdisciplinary StudiesPeking University Department of Materials Science and Engineering College of EngineeringPeking University State Key Laboratory for Mechanical Behavior of Materials Xi'an Jiaotong University

AZ31 magnesium alloy fibers reinforced poly（lactic-co-glycolic acid）（PLGA） composites were prepared and their mechanical property, immersion corrosion behavior and biocompatibility were studied. The tensile test showed that with the addition of AZ31 fibers, the composites had a significant increment in tensile strength and elongation. For the direct cell attachment test, all the cells showed a healthy morphology and spread well on the experimental sample surfaces. The immersion results indicated that pH values of the immersion medium increased with increasing AZ31 fiber contents. All the in vitro experimental results indicated that this new kind of magnesium alloy fibers reinforced PLGA composites show a potential for future biomedical applications.

关键词： Biomaterials Corrosion Polymeric composites AZ31 magnesium fiber

Statistical moment-based structural damage detection method in time domain

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Earthquake Engineering and Engineering Vibration 2013年第1期12卷 13-23页

作者： J.Zhang y.L.Xu J.li y.Xia J.C.li Department of Civil and Environmental Engineering The Hong Kong Polytechnic University Department of Building Engineering Tongji University Faculty of Engineering University of Technology Sydney

A novel structural damage detection method with a new damage index,i.e.,the statistical moment-based damage detection（SMBDD） method in the frequency domain,has been recently *** aim of this study is to extend the SMBDD method in the frequency domain to the time domain for building structures subjected to non-Gaussian and non-stationary *** applicability and effectiveness of the SMBDD method in the time domainis verified both numerically and *** buildings with various damage scenarios are first numerically investigated in the time domain taking into account the effect of measurement *** applicability of the proposed method in the time domain to building structures subjected to non-Gaussian and non-stationary excitations is then experimentally investigated through a series of shaking table tests,in which two three-story shear building models with four damage scenarios *** identified damage locations and severities are then compared with the preset *** comparative results are found to be satisfactory,and the SMBDD method is shown to be feasible and effective for building structures subjected to non-Gaussian and non-stationary excitations.

关键词： damage detection statistical moment time domain non-Gaussian non-stationary experimental investigation

COUPLED SIMULATION OF 3D ELECTRO-MAGNETO-FLOW FIELD IN HALL-HEROULT CELLS USIng FINITE ELEMENT METHOD

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Acta Metallurgica Sinica(English Letters) 2006年第2期19卷 105-116页

作者： J. li W. liu y.Q. Lai Q.y. li y.X. liu School of Metallurgy Science and Engineering Central South University Changsha 410083 China Chemistry Department Guangxi Normal University Guilin 531400 China

Two full 3D steady mathematical models are developed by finite element method （FEM） to calcalate coupled physics fields. the electro-magnetic model is built and solved first and so is the fluid motion model with the acquired electromagnetic force as source body forces in Navier-Stokes equations. Effects caused by the ferromagnetic shell, busbar system around, and open boundary problem as well as inside induced current were considered in terms of the magnetic field. Furthermore, a new modeling method is found to set up solid models and then mesh them entirely with so-called structuralized grids, namely hex-mesh. Examples of 75kA prebaked cell with two kinds of busbar arrangements are presented. Results agree with those disclosed in the literature and confirm that the coupled simulation is valid. It is also concluded that the usage of these models facilitates the consistent analysis of the electric field to magnetic field and then flow motion to the greater extent, local distributions of current density and magnetic flux density are very much dependent on the cell structure, the steel shell is a shield to reduce the magnetic field and flow pattern is two dimensional in the main body of the metal pad.

关键词： coupled simulation electromagnetic field flow field aluminum reduction cell finite element analysis

Motion of the moonlet in the binary system 243 Ida

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Acta Mechanica Sinica 2018年第1期34卷 214-224页

作者： L.Lan y.Ni y.Jiang J.li School of Aerospace Engineering Tsinghua University State Key Laboratory of Astronautic Dynamic Xi'an Satellite Control Center

The motion of the moonlet Dactyl in the binary system 243 Ida is investigated in this paper. First, periodic orbits in the vicinity of the primary are calculated, including the orbits around the equilibrium points and large-scale orbits. The Floquet multipliers’ topological cases of periodic orbits are calculated to study the orbits’ stabilities. During the continuation of the retrograde near-circular orbits near the equatorial plane, two period-doubling bifurcations and one Neimark–Sacker bifurcation occur one by one, leading to two stable regions and two unstable regions. Bifurcations occur at the boundaries of these regions. Periodic orbits in the stable regions are all stable, but in the unstable regions are all unstable. Moreover, many quasi-periodic orbits exist near the equatorial plane. Long-term integration indicates that a particle in a quasi-periodic orbit runs in a space like a tire. Quasi-periodic orbits in different regions have different styles of motion indicated by the Poincare sections. There is the possibility that moonlet Dactyl is in a quasi-periodic orbit near the stable region I, which is enlightening for the stability of the binary system.

关键词： Binary system Bifurcation Periodic orbits Quasi-periodic orbits

Multi-stage Sensitivity Analysis of Distributed Energy Systems: A Variance-based Sobol Method

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Journal of Modern Power Systems and Clean Energy 2020年第5期8卷 895-905页

作者： Shangshang Wei yiguo li Xianhua Gao Kwang y.Lee li Sun Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education and Department of Energy and Environment Southeast UniversityNanjing 210096China IEEE Department of Electrical&Computer Engineering Baylor UniversityWacoTX 76798USA

In the face of the pressing environmental issues,the past decade witnessed the booming development of the distributed energy systems(DESs).A notable problem of DESs is the inevitable uncertainty that may make DESs deviate significantly from the deterministically obtained expectations,in both aspects of optimal design and economic *** thus necessitates the sensitivity analysis to quantify the impacts of the massive parametric *** paper aims to give a comprehensive quantification,and carries out a multi-stage sensitivity analysis on DESs from the perspectives of evaluation criteria,optimal design and economic ***,a mathematical model of a DES is developed to present the solutions to the three stages of the ***,the Monte-Carlo simulation is carried out subject to the probabilistic distributions of the energy,technical and economic *** on the simulation results,the variance-based Sobol method is applied to calculate the individual importance,interactional importance and total importance of various *** comparison of the multi-stage results shows that only a few parameters play critical roles while the uncertainty of most of the massive parameters has little impact on the system *** addition,the influence of parameter interactions in the optimal design stage are much stronger than that in the evaluation criteria and operation strategy stages.

关键词： Sensitivity analysis uncertainty operation design optimization parameter characteristic distributed energy system(DES)