Time filter

Source Type

Huy V.N.,Viet Nam National University | Ngo Q.-A.,National University of Singapore
Computers and Mathematics with Applications

In this present paper, by considering some known inequalities of Ostrowski-like type, we propose a new way to treat a class of Ostrowski-like type inequalities involving n points and m-th derivative. To be precise, the following inequality ({star operator})| frac(1, b - a) ∫a b f (x) d x - frac(b - a, n) underover(∑, i = 1, n) f (a + xi (b - a)) | ≦ frac(2 m + 5, 4) frac((b - a)m + 1, (m + 1) !) (S - s) holds, where S {colon equals} supa ≦ x ≦ b f(m) (x), s {colon equals} infa ≦ x ≦ b f(m) (x) and for suitable x1, x2, ..., xn. It is worth noticing that n, m are arbitrary numbers. This means that the estimate in ({star operator}) is more accurate when m is large enough. Our approach is also elementary. © 2010 Elsevier Ltd. All rights reserved. Source

Huy V.N.,Viet Nam National University | Ngo Q.-A.,National University of Singapore
Mathematical and Computer Modelling

Based on recent results due to Nenad Ujević, we obtain some new inequalities of Simpson-like type involving n knots and the mth derivative where n, m are arbitrary numbers. Our method is also elementary. © 2010 Elsevier Ltd. Source

Tran D.T.,Viet Nam National University | Alleman L.Y.,University of Lille Nord de France | Coddeville P.,University of Lille Nord de France | Galloo J.-C.,University of Lille Nord de France
Building and Environment

Indoor and outdoor airborne particles were monitored with a 5-s time resolution in three elementary schools presenting different site typologies (rural, urban, and industrial) in the North of France. We studied the influence of the children's activities, outdoor sources, temperature and relative humidity on particle mass concentrations and particle mass-size distribution, and estimated cancer risk regarding particle composition.The indoor weekly mean PM10 mass concentrations during teaching hours varied from 70 to 99μgm-3, exceeding the French daily recommended value of 50μgm-3, implying a potential impact on the respiratory system. However, fine particles (<2μm) were always below French daily recommended value of 25μgm-3 applied to PM2.5.The results showed that children's activities impacted the suspended coarse fraction (2-10μm) more strongly than the fine one (<2μm). The mass distribution of indoor PM10 was extremely variable in association with occupant's activities in classrooms whereas the outdoor one seemed to be only lightly variable. During lessons, average concentrations of indoor PM1, PM1-2, PM2-5, and PM5-10 increased respectively by factors of 2.9, 3.1, 8.7 and 33.8 compared to unoccupied periods.Indoor sources from continuous emission and occupant's activities may lead to lower density of indoor PM10 compared to outdoor ones.The estimation of some potential carcinogen elements such as As, Cd, Cr, and Ni in indoor PM2 showed low concentrations in the range of 0.11-1.71ngm-3. Consequently, the cancer risk of these elements was estimated to be not significant for long-term exposure to both children and teachers. © 2014 Elsevier Ltd. Source

Nam N.D.,Viet Nam National University | Long D.T.,Viet Nam National University | Nhan N.V.,Academy of Defence Force Air Force
Integrated Ferroelectrics

The magnetoresistance is one of the important properties of semiconductors. Starting from the hamiltonian for the electron-acoustic phonon system, we obtained the expression for the electron distribution function and especially the expression for the magnetoresistance in quantum wells with parabolic potential (QWPP) under the influence of electromagnetic wave (EMW) in the presence of magnetic field. We estimated numerical values and graphed for a GaAs/GaAsAl quantum well to see the nonlinear dependence of the magnetoresistance on the temperature of the system T, the amplitude E 0 and the frequency Ω of the electromagnetic waves, the magnetic field B, the parameters of the quantum well and the momentum relaxation time τ clearly. © 2014 Taylor & Francis Group, LLC. Source

Discover hidden collaborations