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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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Effects of rhamnolipid biosurfactant JBR425 and synthetic surfactant surfynol465 on the peroxidase-catalyzed oxidation of 2-naphthol

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Journal of Environmental sciences 2013年第7期25卷 1431-1440页

作者： ivanec-Goranina Rūta Kulys Juozas Department of Chemistry and Bioengineering Faculty of Fundamental Sciences Vilnius Gediminas Technical University institute of Biochemistry Vilnius University

The kinetics of the recombinant Coprinus cinereus peroxidase-catalyzed2-naphthol oxidationwas investigated in the presence of rhamnolipid biosurfactant JBR425 and synthetic surfactant surfynol465 at pH 5.5 and25°C,with concentrations of （bio）surfactants both less than critical micelle concentrations （CMC） and larger than CMC. itwas shown that monomers of JBR425 aswell as monomers of surfynol465 had an enhancing effect on the conversion of2-naphthol indose response manner anddid not influence the initial rate of 2-naphthol oxidation. The resultswere accounted by a scheme,which contains a stadium of enzyme inhibition by oligomeric2- naphthol oxidation products. The action of the biosurfactant＇s （or synthetic surfactant＇s） monomerswas explained by avoidance of the enzyme active center clothingwith oligomers. similar results havedemonstrated the potential of rhamnolipid biosurfactant JBR425due to its biodegradability. When biosurfactants＇ concentrations are larger than CMC, （bio）surfactants have an opposite effect on the oxidation of2-naphthol by peroxidase.

关键词： oxidation peroxidase biosurfactant critical micelle concentration

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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 independently 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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sorption of Water-Extractable Organic Carbon in Various Clay subsoils: Effects of soil Properties

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Pedosphere 2016年第1期26卷 55-61页

作者： Trung ta NGUYEN Petra MARsCHNER school of Agriculture Food and Wine The University of Adelaide

Clay-rich subsoils are added to sandy soils to improve crop yield and increase organic carbon （C） sequestration; however, little is known about the influence of clay subsoil properties on organic C sorption and desorption. Batch sorption experiments were conducted with nine clay subsoils with a range of properties. The clay subsoils were shaken for 16 h at 4 ℃with water-extractable organic C （WEOC, 1 224 g C L-1） from mature wheat residue at a soil to extract ratio of 1：10. After removal of the supernatant, the residual pellet was shaken with deionised water to determine organic C desorption. The WEOC sorption was positively correlated with smectite and illite contents, cation exchange capacity （CEC） and total organic C, but negatively correlated with kaolinite content. Desorption of WEOC expressed as a percentage of WEOC sorbed was negatively correlated with smectite and illite contents, CEC, total and exchangeable calcium （Ca） concentrations and clay content, but positively correlated with kaolinite content. The relative importance of these properties varied among soil types. The soils with a high WEOC sorption capacity had medium CEC and their dominant clay minerals were smectite and illite. in contrast, kaolinite was the dominant clay mineral in the soils with a low WEOC sorption capacity and low-to-medium CEC. However, most soils had properties which could increase WEOC sorption as well as those that could decrease WEOC sorption. The relative importance of properties increasing or decreasing WEOC sorption varied with soils. The soils with high desorption had a low total Ca concentration, low-to-medium CEC and low clay content, whereas the soils with low desorption were characterised by medium-to-high CEC and smectite and illite were the dominant clay minerals. We conclude that WEOC sorption and desorption depend not on a single property but rather a combination of several properties of the subsoils in this study.

关键词： cation exchange capacity, clay mineral illite, kaolinite smectite

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ＬＯＣＡＬＥＸＡＣＴＢＯＵＮＤＡＲＹＣＯＮＴＲＯＬＬＡＢＩＬＩＴＹＦＯＲＡＣＬＡＳＳＯＦＱＵＡＳＩＬＩＮＥＡＲＨＹＰＥＲＢＯＬＩＣＳＹＳＴＥＭＳ

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Chinese Annals of Mathematics,series B 2002年第2期23卷 209-218页

作者：ＬＩＴＡ－ＴＳＩＥＮＲＡＯ ВＯＰＥＮＧＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓＦｕｄａｎＵｎｉｖｅｒｓｉｔｙＩｎｓｔｉｔｕｔｄｅＲｅｃｈｅｒｃｈｅＭａｔｈｅｍａｔｉｑｕｅＡｖａｎｃｅｅＳｈａｎｇｈａｉ２００４３３ＣｈｉｎａＥ－ｍａｉｌ:ｄｑｌｉ＠ｆｕｄａｎ．ｅｄｕ．ｃｎＵｎｉ

For a class of mixed initial-boundary value problem for general quasilinear hyperbolic systems, this paper establishes the local exact boundary controllability with boundary controls only acting on one end. As an application, the authors show the local exact boundary controllability for a kind of nonlinear vibrating string problem.

关键词： Exact boundary controllability Quasilinear hyperbolic system Nonlinear vibrating string equation

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Bottomonium spectrum with screened Potential

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Communications in Theoretical Physics 2009年第10期52卷 653-661页

作者： Li Bai-Qing CHAO Kuang-ta Department of Physics and state Key Laboratory of Nuclear Physics and Technology Peking University Beijing 100871 China Department of Physics Huzhou Teachers College Huzhou 313000 China

As a sister work of[Phys. Rev. D 79 （2009） 094004], we incorporate the color-screening effect due to light quark pair creation into the heavy quark-antiquark potential, and investigate the effects of screened potential on the spectrum of bottomonimn. We calculate the masses, electromagnetic decays, and E1 transitions of bottomonium states. We find that the fine splittings between χbJ （J = 0, 1, 2） states are in good agreement with experimental data, and the E1 transition rates of γ（2s） → γχbJ（1P） and γ（3s） →γχbJ（2P）（J = 0, 1, 2） all agree with data within experimental errors. in particular, the mass of γ（6s） is lowered down to match that of the γ（11020）, which is smaller than the predictions of the linear potential models by more than 100 MeV. Comparison between charmonium and bottomonium in some related problems is also discussed.

关键词： color-screening effect Bottomonium

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On the Non-Commutative Neutrix Product of the Distributions x＋^λ and x^＋μ

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Acta Mathematica sinica,English series 2006年第6期22卷 1639-1644页

作者： B.FisHER K.ta■ Department of Mathematics University of Leicester Department of Mathematics Cankaya University

Let f and g be distributions and let gn = （g ＊ δn）（x）, where δn （x） is a certain converging to the Dirac delta function. The non-commutative neutrix product fog of f and g to be the limit of the sequence {fgn }, provided its limit h exists in the sense that sequence is defined N-lim n-∞（f（x）g,, （x）, φ（x）〉 = （h（x）, φ（x）},for all functions p in 2. it is proved that （x^λ＋1n^px＋）0（x^μ＋1n^qx＋）=x＋^λμ1n^p＋qx＋,（x^λ-1n^qx-）=x-^λ＋μ1n^p＋qx-,for λ＋μ〈-1; λ,μ, λ＋μ≠-1,-2…and p,q=0,1,2……

关键词： distribution delta function product of distributions

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Blood Pressure and Heart Rate Measurements Using Photoplethysmography with Modified LRCN

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Computers, Materials & Continua 2022年第4期71卷 1973-1986页

作者： Chih-ta Yen Cheng-Hong Liao Department of Electrical Engineering Taiwan Ocean UniversityKeelung City202301Taiwan Department of Electrical Engineering National Formosa UniversityYunlin County632Taiwan

in this study,single-channel photoplethysmography(PPG)signals were used to estimate the heart rate(HR),diastolic blood pressure(DBP),and systolic blood pressure(sBP).A deep learning model was proposed using a long-term recurrent convolutional network(LRCN)modified from a deep learning algorithm,the convolutional neural network model of the modified inception deep learning module,and a long short-term memory network(LsTM)to improve the model’s accuracy of BP and HR *** PPG data of 1,551 patients were obtained from the University of California irvine Machine Learning *** to design a filter of PPG signals and how to choose the loss functions for deep learning model were also discussed in the ***,the stability of the proposed model was tested using a 10-fold cross-validation,with an MAE±sD of 2.942±5.076 mmHg for sBP,1.747±3.042 mmHg for DBP,and 1.137±2.463 bpm for the *** with its existing counterparts,the model entailed less computational load and was more accurate in estimating sBP,DBP,and *** results established the validity of the model.

关键词： Photoplethysmography(PPG)signal deep learning blood pressure systolic blood pressure(sBP) diastolic blood pressure(DBP) heart rate(HR)

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Design of Floating Mass Type Piezoelectric Actuator for implantable Middle Ear Hearing Devices

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Chinese Journal of Mechanical Engineering 2009年第2期22卷 221-226页

作者： LiU Houguang ta Na MiNG Xiaofeng RAO Zhushi state Key Laboratory of Mechanical system and Vibrations Shanghai Jiao Tong University Shanghai 200240 China

To overcome some of the problems inherent in conventional heating aids such as low gain at high fi＇equencies due to acoustic feedback, discomfort in occlusion of the extemal ear canal and so on, implantable middle ear hearing devices （iMEHDs） have been developed over the past two decades. For such kinds of iMEHDs, this paper presents the design of a floating mass piezoelectric actuator using a PMN-30%PT stack as a new type of vibrator. The proposed piezoelectric actuator consists of only three components of a piezoelectric stack, a metal case and a clamp. For the purpose of aiding the design of this actuator, a coupling biomechanics model of human middle ear and the piezoelectric actuator was constructed. This model was built based on a complete set of computerized tomography section images of a healthy volunteer＇s left ear by reverse engineering technology. The validity of this model was confirmed by comparing the motion of the tympanic membrane and stapes footplate obtained by this model with published experimental measurements on human temporal bones. it is shown that the designed actuator can be implanted on the incus long process by a simple surgical operation, and the stapes footplate displacement by its excitation at 10.5 V root-mean-square（RMs） voltage was equivalent to that from acoustic stimulation at 100 dB sound pressure level（sPL）, which is adequate stimulation to the ossicular chain. The corresponding power consumption is 0.04 mW per volt of excitation at 1 kHz, which is low enough for the transducer to be used in an implantable middle ear device.

关键词： piezoelectric actuator implantable middle ear hearing device floating mass fmite element model

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The long and the short of it： new insights on sperm length help demystify the complexities of sexual selection

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Asian Journal of Andrology 2016年第6期18卷 902-903页

作者： Alexander K Hill Dan ta Eisenberg Department of Anthropology University of Washington Seattle WA 98195 USA

Human sperm are approximately 6000th of a centimeter long, a smallfraction of a man＇s total body length. By contrast, fruit fly （Drosophila spp.） sperm can reach nearly 6 cm, roughly twenty times the total length of their bodies. This dramatic variation in male reproductive biology is explored in a recent paper from the journal Nature.

关键词： @@

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