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Impact of chosen force fields and applied load on thin film lubrication

Friction 2021年第5期9卷 1259-1274页

作者： Thi d.ta hien d.ta Kiet A.TIEU Bach H.TRAN School of Mechanical MaterialsMechatronicsand Biomedical EngineeringUniversity of WollongongNSW 2522Australia Ho Chi Minh City University of Technology and Education Ho Chi Minh City 800010Vietnam

The rapid development of molecular dynamics(Md)simulations,as well as classical and reactive atomic potentials,has enabled tribologists to gain new insights into lubrication performance at the fundamental ***,the impact of adopted potentials on the rheological properties and tribological performance of hydrocarbons has not been researched *** extensive study analyzed the effects of surface structure,applied load,and force field(FF)on the thin film lubrication of *** lubricant film became more solid‐like as the applied load *** particular,with increasing applied load,there was an increase in the velocity slip,shear viscosity,and *** degree of ordering structure also changed with the applied load but rather *** was also significantly dependent on the surface *** chosen FFs significantly influenced the lubrication performance,rheological properties,and molecular *** adaptive intermolecular reactive empirical bond order(AIREBO)potential resulted in more significant liquid‐like behaviors,and the smallest velocity slip,degree of ordering structure,and shear stress were compared using the optimized potential for liquid simulations of united atoms(OPLS‐UAs),condensed‐phase optimized molecular potential for atomic simulation studies(COMPASS),and ***,classical potentials,such as OPLS‐UA and COMPASS,exhibit more solid‐like behavior than reactive potentials ***,owing to the solid‐like behavior,the lubricant temperatures obtained from OPLS‐UA and COMPASS were much lower than those obtained from AIREBO and *** increase in shear stress,as well as the decrease in velocity slip with an increase in the surface potential parameterζ,remained conserved for all chosen FFs,thus indicating that the proposed surface potential parameterζfor the COMPASS FF can be verified for a wide range of atomic models.

关键词： molecular dynamics simulation force fields applied load tribofilm hydrocarbon

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Coexistence Between Massive MIMO and Radar Communications:Performance Analysis

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Journal of Communications and Information Networks 2023年第1期8卷 37-47页

作者： Mohamed Elfiatoure hien Quoc Ngo Michail Matthaiou Centre for Wireless Innovation(CWI) Queen’s University BelfastBelfast BT39DTUK

Frequency spectrum sharing between radar and communication systems has recently attracted substantial *** consider the coexistence between a massive multiple-input multiple-output(MIMO)downlink system and MIMO radar to enable the operation of these two systems with minimal mutual *** an asymptotic analysis,we show that by using more antennas at the base station(BS),we can improve the performance of massive MIMO,while keeping the interference to the radar system ***,if we use a large number of antennas at the BS and make the transmit power inversely proportional to the number of antennas,we can avoid the interference from the massive MIMO system to the radar system,with no compromise in the performance of the massive MIMO ***-form expressions for the probability of detection of the radar system and the downlink spectral efficiency of the massive MIMO system,are ***,we propose a power allocation scheme which selects the transmit powers at the MIMO radar and BS to maximize the probability of detection for the MIMO ***,the optimal power allocation can be determined in *** results provide valuable insights into the practical coexistence between massive MIMO and radar systems.

关键词： massive MIMO radar-communication coexistence spectrum sharing

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Thiol-yne Click Adamantane Monolithic Stationary Phase for Capillary Electrochromatography

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Chinese Journal of Chemistry 2012年第10期30卷 2281-2284页

作者： dao,Thi Thu hien Guerrouache,Mohamed Carbonnier,Benjamin Institut de Chimie et des Materiaux Paris Est UMRCNRS 7182&Universite Paris-Est Creteil2-8 rue Henri Dunant94320 ThiaisFrance

A porous crosslinked organic polymer based on N-acryloxysuccinimide （NAS） and ethylene dimethacrylate （EdMA） was prepared inside 75 μm i.d. fused silica capillary as functionalizable monolithic stationary phase for electrochromatographic applications. Succinimide groups on the monolith surface provide reactive sites able to re- act readily through standard electrophile-nucleophile chemistry. Propargylamine was used to prepare alkyne func- tionalized poly（NAS-co-EdMA）. Onto this thiol-reactive polymer surface was grafted adamantane units via a photochemically-driven addition reaction. Chemical characterization was performed in situ after each synthetic step by means of Raman spectroscopy and grafting kinetics was investigated to ensure quantitative grafting of 1-adamantanethiol. The as-designed monolithic stationary phase exhibited typical reversed-phase separation mechanism as evidenced by the linear increase of the logarithm of retention factor of neutral aromatic solutes with the increase of the aqueous buffer content in the mobile phase.

关键词： adamantane electrochromatography porous monolith surface chemistry thiol-yne click

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dynamic behavior of stormwater quality parameters in South Texas

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Frontiers of Environmental Science & Engineering 2012年第6期6卷 825-830页

作者： Xubin PAN Jingyi ZHANG Wei-ta FANG Kim d.JONES Institute of Plant Quarantine Chinese Academy of Inspection and QuarantineBeijing 100029China department of Environmental Engineering Texas A&M University-KingsvilleKingsvilleTX 78363USA Graduate Institute of Environmental Education Taiwan Normal UniversityTaipei 116China

To control water impairment in urban storm- water, it is important to evaluate changing patterns of water quality parameters in stormwater runoff. Thus, the authors performed a series of experiments to investigate the dynamics of common water parameters during storm events in semi-arid areas, with multiple samples collected and analyzed in field stormwater applications. At this field monitoring site within McAuliffe Park, McAllen, Texas, in the United States, a storm event increased the concentra- tions of Escherichia coli （E. coli）, but this event represented a decreasing trend over the entire event period. Besides, peak intensity of different pollutants in the stormwater runoff occurred at different times other than at any peak flows, representing a complexity of the temporal and spatial measurements. Multi-sample per- event approaches recommended based on the complexity of the hydrograph and different peak intensity times of pollutants. In addition, high bacteria and total suspended solids （TSS） concentrations in the initial stage of the storm event should be considered when designing Best Manage- ment Practices （BMPs） and Low Impact developments （LIds）. New strategies and solutions for addressing ecohydrological challenges should be proposed to avoid collateral damages to their both common wealth in ecosystems and human well-beings.

关键词： event mean concentration first flush multi-sample per event ecohydrology

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Advances in haemostatic sponges: Characteristics and the underlying mechanisms for rapid haemostasis

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Bioactive Materials 2023年第9期27卷 231-256页

作者： Akriti Nepal Huong d.N.Tran Nam-Trung Nguyen Hang Thu ta Queensland Micro-and Nanotechnology Centre Griffith UniversityNathanQueensland4111Australia Australian Institute for Bioengineering and Nanotechnology University of QueenslandSt LuciaQueensland4072Australia Bioscience discipline School of Environment and ScienceGriffith UniversityNathanQueensland4111Australia

In traumatized patients, the primary cause of mortality is uncontrollable continuous bleeding and unexpected intraoperative bleeding which is likely to increase the risk of complications and surgical failure. High expansion sponges are effective clinical practice for the treatment of wound bleeding (irregular/deep/narrow) that are caused by capillaries, veins and even arterioles as they possess a high liquid absorption ratio so can absorb blood platelets easily in comparison with traditional haemostasis treatments, which involve compression, ligation, or electrical coagulation etc. When in contact with blood, haemostatic sponges can cause platelet adhesion, aggregation, and thrombosis, preventing blood from flowing out from wounds, triggering the release of coagulation factors, causing the blood to form a stable polymerized fibre protein, forming blood clots, and achieving the goal of wound bleeding control. Haemostatic sponges are found in a variety of shapes and sizes. The aim of this review is to facilitate an overview of recent research around haemostatic sponge materials, products, and technology. This paper reviews the synthesis, properties, and characteristics of haemostatic sponges, together with the haemostasis mechanisms of haemostatic sponges (composite materials), such as chitosan, cellulose, gelatin, starch, graphene oxide, hyaluronic acid, alginate, polyethylene glycol, silk fibroin, synthetic polymers silver nanoparticles, zinc oxide nanoparticles, mesoporous silica nanoparticles, and silica nanoparticles. Also, this paper reviews commercial sponges and their properties. In addition to this, we discuss various in-vitro/in-vivo approaches for the evaluation of the effect of sponges on haemostasis .

关键词： Haemostatic sponge Characteristics Mechanism Haemostasis Nanoparticles

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A Raman Study of the Origin of Oxygen defects in Hexagonal Manganite Thin Films

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Chinese Physics Letters 2012年第12期29卷 148-151页

作者： CHEN Xiang-Bai hien Nguyen Thi Minh YANG In-Sang LEE daesu NOH tae-Won department of Nano Science&Mechanical Engineering and Nanotechnology Research Center Konkuk UniversityChungju 380-701Korea 2Department of Physics and Division of Nano-SciencesEwha Womans UniversitySeoul 120-750Korea 3ReCFIDepartment of Physics and AstronomySeoul National UniversitySeoul 151-747Korea

Oxygen defects are usually unavoidable when synthesizing oxide thin *** study the origin of the oxygen defects in hexagonal manganite HoMnO_(3) epitaxial thin films through Raman scattering *** results show that the oxygen defects in hexagonal HoMnO_(3) thin films have distinct effects on different phonon modes and on magnon *** analyses indicate that the oxygen defects in hexagonal HoMnO_(3) thin films mainly originate from the basal O3 and/or O4 oxygen ***,our analyses of oxygen defects predict that the Mn 3d orbitals would be more strongly hybridized with the apical O1 and/or O22p orbitals than the basal O3 and/or O42p *** prediction is consistent with our resonant Raman scattering study and earlier first-principle calculations of the electronic structures of hexagonal manganites.

关键词： spectroscopy. hexagonal Oxygen

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Unit-cell design for two-dimensional phase-field simulation of microstructure evolution in single-crystal Ni-based superalloys during solidification

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Progress in Natural Science:Materials International 2017年第6期27卷 678-686页

作者： dongjia Cao Na ta Lijun Zhang State Key Lab of Powder Metallurgy Central South University Interdisciplinary Centre for Advanced Materials Simulation (ICAMS) Ruhr-University Bochum

Phase-field simulation serves as an effective tool for quantitative characterization of microstructure evolution in single-crystal Ni-based superalloys during solidification nowadays. The classic unit cell is either limited to γdendrites along crystal orientation or too ideal to cover complex morphologies for γ dendrites. An attempt to design the unit cell for two-dimensional(2-d) phase-field simulations of microstructure evolution in single-crystal Ni-based superalloys during solidification was thus performed by using the MICRESS(MICRostructure Evolution Simulation Software) in the framework of the multi-phase-field(MPF) model,and demonstrated in a commercial TMS-113 superalloy. The coupling to CALPHAd(CALculation of PHAse diagram) thermodynamic d.tabase was realized via the TQ interface and the experimental diffusion coefficients were utilized in the simulation. Firstly, the classic unit cell with a single γ dendrite along crystal orientation was employed for the phase-field simulation in order to reproduce the microstructure ***, such simple unit cell was extended into the cases with two other different crystal orientations, i.e., and . Thirdly, for crystal orientations, the effect of γ dendritic orientations and unit cell sizes on microstructure and microsegregation was comprehensively studied, from which a new unit cell with multiple γdendrites was proposed. The phase-field simulation with the newly proposed unit cell was further performed in the TMS-113 superalloy, and the microstructure features including the competitive growth of γ dendrites,microsegregation of different solutes and distribution of γ′ grains, can be nicely reproduced.

关键词： Ni-based superalloys Solidification Microstructure Phase-field simulation Unit cell

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Piaoac Granites Related W-Sn Mineralization, Northern Vietnam: Evidences from Geochemistry, Zircon Geochronology and Hf Isotopes

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Journal of Earth Science 2019年第1期30卷 52-69页

作者： Tuan Anh Nguyen Xiaoyong Yang hien Vu Thi Lei Liu Insung Lee School of Earth and Space Sciences University of Science and Technology of China Institute of Geological Sciences Vietnam Academy of Science and Technology(VAST) department of Geology Hanoi University of Mining and Geology School of Earth and Environmental Sciences Seoul National University

Piaoac granites exposed in the Cao Bang region, northern Vietnam, are S-type granite, which are associated with W-Sn-Mo-Be-F mineralization. Zircon U-Pb ages, major and trace elements, mineral chemical and Hf isotopic compositions of the W-Sn-bearing granites from the Piaoac district have been investigated in d.tail. LA-ICP-MS U-Pb dating of zircon grains from these granites yielded ages of 82.5±2.3 and 82±1.8 Ma, representing an episode of Late Cretaceous magmatic event. These granites are characterized by high peraluminous and have typical S-type geochemical signatures with high SiO_2(72.37 wt.%–73.07 wt.%), high A/CNK values(1.61–1.65) and Al_2O_3(14.4 wt.%–15 wt.%). They are enriched in Rb, U, K, Th, ta and Pb and display pronounced negative Ba, Sr, Nb, Ti and Eu(Eu/Eu*=0.19–0.24) anomalies. The high degree of fractional crystallization is characterized by low Rb, Sr, Ba and Eu concentrations with high ratios of La/Sm and Eu/Eu*. Zircon grains show εHf(t) values from-9.69 to-0.9 and the corresponding TdM2 range from 1.2 to 1.7 Ga, indicating that these granites could be derived from the Proterozoic basement rocks with minor input from mantle-derived magmas. The calculation of Fe^(3+) and Fe^(2+) of biotites indicates a low oxygen fugacity condition(log fO_2 ranging from 10-17 to 10-18 bars, below MH), which is favorable for the W-Sn mineralization. Tungsten and tin have been enriched in granitic magmas through fractionation, and low oxygen fugacity conditions have promoted the accumulation and transportation of W-Sn in the hydrothermal fluids, leading to deposition of mineral phases. The geochemical d.ta suggest that Piaoac granites formed in an extensional setting related with the Late Cretaceous magmatism occurring large-scale lithospheric extensional in South China Block.

关键词： geochemistry zircon U-Pb age Hf isotope Piaoac granite W-Sn mineralization Northern Vietnam

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Soil Respiration, Microbial Biomass and Nutrient Availability in Soil After Addition of Residues with Adjusted N and P Concentrations

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Pedosphere 2017年第1期27卷 76-85页

作者： Trung ta NGUYEN Petra MARSCHNER School of Agriculture Food and Wine The University of Adelaide Adelaide 5005 (Australia)

Microbial activity and nutrient release are known to be influenced by organic matter properties,but it is difficult to separate the effect of C/N ratio from that of C/P ratio because in most plant residues both ratios are either high or *** incubation experiment was conducted to investigate the effects of reducing the C/N and C/P ratios of slowly decomposable plant residues(young eucalyptus leaves,mature wheat straw,and sawdust) to those of rapidly decomposable residues(young kikuyu shoots) on soil respiration,microbial biomass,and N and P *** C/N and C/P ratios of the former were adjusted to 15 and 89,respectively,by adding N as(NH_4)_2SO_4,P as KH_2PO_4 or both and residues were added at 10 g C kg-1 to a silt *** respiration was measured over21 d;microbial biomass C(MBC) and available N and P were measured on days 0,7,and *** to the unamended soil,addition of kikuyu increased cumulative respiration 20-fold,MBC concentration 4 to 8-fold,and available P concentration up to4-fold,whereas the increase in available N concentration was small and *** respiration and MBC concentration were low in the sawdust-amended soil and were not influenced by reducing the C/N and C/P *** respiration with original wheat and eucalyptus was 30%-40%of that with *** the C/N ratio alone or both C/N and C/P ratios increased cumulative respiration and MBC concentration 2-fold compared to the original wheat and eucalyptus,whereas reducing the C/P ratio had little *** the experiment,the available N concentration after addition of residues with reduced C/N ratio increased in the following order of eucalyptus dependently lowering the C/N and C/P ratios,microbial activity was more limited by C and N than ***,lowering the C/N ratio of very slowly decomposable sawdust had no effect on soil respiration and MBC concentration,suggesting that other properties such as concentration of poor

关键词： C/N ratio C/P ratio microbial activity nutrient immobilisation nutrient mineralisation

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THE C_M-EMBEddEd PROBLEM ANd OPTIMALITY CONdITIONS

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Acta Mathematicae Applicatae Sinica 1990年第1期6卷 22-34页

作者：夏尊铨 STROdIOT J.-J. NGUYEN V.hien Facultes Universitaires N.d.de la Paix Facultes Universitaires N.d.de la Paixn this paper the C_M-embedded problem which is also called the design centering problem inother papers will be described and new optimality conditions and some results associated withoptimality conditions will be presented. These results hold for general non-convex regions. To acertain extent they provide the possibility to develop search techniques. It should be pointed outthat in this paper the only case where the Minkowski norm is just the Euclidean norm is treated.

In this paper the C_M-embedded problem which is also called the design centering problem inother papers will be described, and new optimality conditions and some results associated withoptimality conditions will be presented. These results hold for general non-convex regions. To acertain extent they provide the possibility to develop search techniques. It should be pointed outthat, in this paper, the only case where the Minkowski norm is just the Euclidean norm is treated.

关键词：一夕

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