Papers by Mau Nguyen Dang
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This study represents a pioneering effort to establish a downscaling framework named "land-surfac... more This study represents a pioneering effort to establish a downscaling framework named "land-surface-physics-based downscaling" (LSP-DS) for agricultural meteorological prediction in the tropical-monsoon region of the Red River Delta, Vietnam. The primary focus of this article is to evaluate the performance of LSP-DS on meteorological variables, specifically temperature and humidity. In details, LSP-DS, which is based on the NCAR's Noah Multi-Parameterizations land surface model, incorporated by recently developed land use/cover data for Vietnam released by JAXA, is forced by ERA5 data for 2013; and the results are compared with ground-based station observations. The results exhibit excellent performance of LSP-DS versus observations with consistently high correlation coefficient between the two, highlighting the high potential of using LSP-DS for realtime operational forecast. The LSP-DS performance varies with different sub land use/cover categories, implying that the proper parameter settings could be key point for improvement. The findings of this research underscore the dual strengths of the LSP-DS approach: its computational efficiency and its remarkable efficacy in predicting spatial heterogeneity of local climates. These attributes render it well-suited for agrometeorological forecasting in a tropical monsoon climate, exemplified by the Red River Delta in Vietnam.
Http Www Theses Fr, 1994
Nous avons entrepris une etude systematique sur le comportement rheologique, la percolation et l&... more Nous avons entrepris une etude systematique sur le comportement rheologique, la percolation et l'endommagement de materiaux contenant la phase intergranulaire eutectique. Cette etude a ete realisee a des temperatures englobant la temperature de fusion de la phase eutectique en vue d'obtenir deux types de joints: solide ou liquide. Tout au long de cette etude, nous nous sommes attaches a comparer le comportement du materiau a joints solides visqueux a celui du materiau a joints liquides. Un modele morphologique des grains avec des poches liquides a ete propose, ce qui permet de determiner la fraction volumique de l'interphase. Le comportement du materiau peut etre presente dans un diagramme de type ashby en prenant en compte la nature des joints de grains. Le mecanisme de dissolution-diffusion-precipitation du a la contrainte normale est important lorsque l'interphase est liquide. Ceci provoque une croissance de la surface des contacts entre les grains lors des essais en compression, notamment en compression triaxiale. L'etude de la percolation de la phase intergranulaire montre que cette percolation est provoquee par le gradient de la contrainte locale et depend de la viscosite de l'interphase. L'endommagement se produit dans les joints solides visqueux ou liquides et depend de la contrainte locale en traction s'exercant sur ces joints. Cette contrainte en traction peut etre compensee par la pression effective au cours de deformation en compression triaxiale, ce qui reduit l'endommagement. Comme la percolation est un mecanisme d'accomodation, moins il y a de liquide, plus la percolation est difficile et plus l'endommagement est important
Annales d'endocrinologie, 1997
The aim of a cancer registry is to study the incidence of cancer in a well-determined population ... more The aim of a cancer registry is to study the incidence of cancer in a well-determined population and to allow epidemiological research to the setting up of diagnosis and therapeutic strategies. The Belgian Thyroid Cancer Study Group (BTCSG) was founded in 1990. In the present study we report data collected from 1988 to 1995 in 397 patients with a differentiated (papillary and follicular) thyroid carcinoma living in the french-speaking area of Belgium. The sex ratio female/male is 3.5 and the median ages at the diagnosis, is similar (45 yrs, 12-82) in both sexes. Seven cases of thyroid cancer were registered in young patients less than 18 yrs old. Thyroid carcinoma were associated with multinodular goiter in more than 50% cases. Cancer was bilateral in 17%. Papillary histological type accounts for 84% in our series while its diagnosis was established in 45% at early clinical stages (TO-T1). These observations could probably be related with 1) broader indications and more aggressive o...
Advances in Natural Sciences: Nanoscience and Nanotechnology, 2014
In this paper we present silver nanoparticles ink synthesis targeting conductive patterns for mic... more In this paper we present silver nanoparticles ink synthesis targeting conductive patterns for micro fabricated devices by inkjet printing technology. The well dispersed nanoparticles ink was composed of silver colloid with an average particle diameter less than 10 nm. These nanoparticles were protected by a capping layer of poly(N-vinylpyrrolidone) (PVP) even at silver concentration of 20 wt%. Stable aqueous inks were formulated by using a combination of solvent and co-solvents and under vigorous stirring. Various factors affecting the adhesion between the ink and the substrate were investigated, such as solvent and co-solvent content. The ink containing 20 wt% silver has a viscosity of about 9.5 cP and a surface tension of 32 to 36 mN m−1 at room temperature, meeting inkjet printer requirements. The ink stored under ambient conditions was stable against aggregation for more than one month. Silver nanoparticles patterns have been successfully printed on various substrates.
Revue médicale de Liège, 2006
Different factors can have deleterious effect the inspiratory muscles: increased intrinsic mechan... more Different factors can have deleterious effect the inspiratory muscles: increased intrinsic mechanical loading of the inspiratory muscles, functional inspiratory muscle weakness, increased ventilatory demand related to capacity... These muscle changes influence exercise tolerance and contribute to dyspnea.
The European Physical Journal Applied Physics, 2014
Application of the radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) technique... more Application of the radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) technique was studied to fabricate amorphous and nanocrystalline silicon (a-Si and nc-Si) thin films for photovoltaic devices at substrate temperature of 200 • C. Amorphous-crystalline transition of silicon thin films in working conditions of PECVD system was shown as a function of deposition parameters, i.e., dilution ratio of silane (SiH4) in hydrogen, total gas pressure during deposition and RF excitation power density. The crystalline volume as well as grain size of nanocrystalline silicon films could be successfully controlled by tuning those deposition parameters. Micro Raman scattering spectroscopy and spectroscopic ellipsometry (SE) methods were used to characterize the structure and crystallization of the deposited silicon thin films. We could make nc-Si thin films with various crystalline volumes. Nc-Si grain size was also controlled and was in the range of 3-5 nm.
Advances in Natural Sciences: Nanoscience and Nanotechnology, 2013
Inkjet printing is an advanced technique which reliably reproduces text, images and photos on pap... more Inkjet printing is an advanced technique which reliably reproduces text, images and photos on paper and some other substrates by desktop printers and is now used in the field of materials deposition. This interest in maskless materials deposition is coupled with the development of microfabrication techniques for the realization of circuits or patterns on flexible substrates for which printing techniques are of primary interest. This paper is a review of some results obtained in inkjet printing technology to develop microfabrication techniques at Laboratory for Nanotechnology (LNT). Ink development, in particular conductive ink, study of printed patterns, as well as application of these to the realization of radio-frequency identification (RFID) tags on flexible substrates, are presented.
Advances in Natural Sciences: Nanoscience and Nanotechnology, 2012
In this study, silver nanoparticles were synthesized from silver nitrate via a polyol method in a... more In this study, silver nanoparticles were synthesized from silver nitrate via a polyol method in ambient atmosphere. In our synthesis route, polyvinylpyrrolidone (PVP) is used as both size controller and capping agent, ethylene glycol acts both as solvent and reducing agent. The obtained silver nanoparticles were characterized by ultraviolet-visible spectrophotometry which indicated the formation of nanoparticles. Investigation of Fourier transform infrared spectroscopy clearly demonstrated the coordination between silver nanoparticles and PVP. Transmission electron microscopy (TEM) contributed to the particle size analysis. The surface plasmon resonance peak in absorption spectra of silver colloidal solution showed absorption from 406 to 409 nm. The average size of the resulting silver nanoparticles was below 10 nm with a dependency on the PVP concentration.
Advances in Natural Sciences: Nanoscience and Nanotechnology, 2014
ABSTRACT Compared to the conventional silicon-based technology, the solution process appears to b... more ABSTRACT Compared to the conventional silicon-based technology, the solution process appears to be a revolution in the field of micro/nanofabrication due to its advantages of high efficiency in material and energy consumption and the use of low cost material. In this paper, we introduce a new approach to fabricate BioMEMS devices using this novel technology to make microcavity. Zirconium oxide patterns were formed on the silicon substrate simply by spin coating its precursor and thermal imprinting technique. We used poly-propylene carbonate (PPC) for the sacrificial material due to its unique pyrolysis property. The PPC was coated on the ZrO patterns and excess film was etched by oxygen plasma but retaining PPC structure between the lines of ZrO pattern. Then another ZrO layer was coated to encapsulate the PPC. The final microcavity structures were obtained by just baking the substrate by pyrolyzing the PPC. The obtained results show the approach's prospect of becoming an ideal alternative for the current BioMEMS micro/nanofabrication technologies
Advances in Natural Sciences: Nanoscience and Nanotechnology, 2010
Nanocrystalline N-doped SiO 2/TiO 2 visible-light photocatalyst thin films were synthesized using... more Nanocrystalline N-doped SiO 2/TiO 2 visible-light photocatalyst thin films were synthesized using the sol-gel method on glass substrates. The synthesized catalysts were then characterized using several analytical techniques like x-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AFM), and UV–vis absorption spectroscopy (UV–vis). The experimental results revealed that the maximum optical response of the synthesized SiO 2/TiO 2 thin films shifted from the ultraviolet (UV) to the visible-light region (λ⩾420 nm). The photocatalytic activity of N-doped SiO 2–TiO 2 photocatalyst was considerably higher than that of SiO 2–TiO 2, and this result was obtained with an optimal concentration of 40 mol% of N. The enhanced photocatalytic activity was attributed to the increasing surface area and forming more hydroxyl groups in the doped catalyst.
Respiration, 2006
Background: Long-term oxygen therapy (LTOT) is the cornerstone mode of treatment in patients with... more Background: Long-term oxygen therapy (LTOT) is the cornerstone mode of treatment in patients with chronic obstructive pulmonary disease (COPD). Objectives: The present study aims to investigate the effect of two oxygen sources (concentrator and liquid oxygen) on quality of life, exercise tolerance and compliance to LTOT in patients with COPD. Methods: The survey included 104 patients with COPD (31 on concentrator treatment and 73 on liquid oxygen). Patients were subjected to pulse oximetry, basic spirometry, measurement of health-related quality of life by the St. George’s Hospital respiratory questionnaire instrument and assessment of dyspnoea severity by the modified Borg category scale. Exercise tolerance was evaluated by the SaO2 value after 3 min of walking. SaO2 was measured before and after treatment with each device. Compliance with therapy was defined by the daily duration of oxygen use. Results: The two LTOT groups did not differ significantly concerning pulmonary function...
Advances in Meteorology
Central Vietnam is characterized by severe flooding associated with heavy rainfall events caused ... more Central Vietnam is characterized by severe flooding associated with heavy rainfall events caused by interactions between multiscale atmospheric circulations and the complex local terrain. Previous studies believed rainfall in central Vietnam is closely related to the cold surge; however, it fails to explain the cause of the early rainfall occurrence in August in the subregion. For the first time, this study investigates the detailed atmospheric mechanisms associated with rainfall variations in central Vietnam using the empirical orthogonal function (EOF) applied to the recently developed high-resolution Vietnam gridded precipitation (VnGP) dataset. Reanalysis data NCEP/NCAR is used to associate the rainfall changes with respective atmospheric mechanisms. EOF analysis detected two dominant rainfall modes. The primary mode explains the rainfall variation from October to November over the central and is directly related to the interaction of cold surges and tropical disturbances. The s...
Advances in Natural Sciences: Nanoscience and Nanotechnology, 2013
ABSTRACT The use of carbon nanotubes (CNTs) in radio frequency identification (RFID) applications... more ABSTRACT The use of carbon nanotubes (CNTs) in radio frequency identification (RFID) applications offers a very large range of possibilities to exploit the incredible properties of CNTs. However, due to their entanglement state, their size and the different interacting forces between nanotubes bundles present at nanometric scale, CNTs debundling is very hard to achieve, requiring specific equipment and chemicals. Our purpose was to reduce as small as possible CNTs bundles, in order to realize ink to print on an RFID antenna. The size of the head printer nozzles required very small particles, about a few micrometers, in order to be able to print on the sensitive position of the antenna. To reduce the size of the bundles and stabilize the solution, an ultrasonic horn with an ultrasonic bath were combined as mechanical stress for CNT dispersion, and some chemicals such as sodium dodecyl sulfate (SDS)—a surfactant, N-methyl-2-pyrrolidone (NMP)—a solvent, or chitosan were used to meet our requirements.
Advances in Natural Sciences: Nanoscience and Nanotechnology, 2014
Functional screen printed radio frequency identification tags on flexible substrates, facilitatin... more Functional screen printed radio frequency identification tags on flexible substrates, facilitating low-cost and integrated point-ofcare diagnostics Suzanne Smith, Adelaide Oberholzer, Kevin Land et al.-Inkjet printing technology and conductive inks synthesis for microfabrication techniques
Advances in Natural Sciences: Nanoscience and Nanotechnology, 2010
In this work, the surface of platinum (Pt) nanowires was modified by using several chemicals, inc... more In this work, the surface of platinum (Pt) nanowires was modified by using several chemicals, including a compound of gelatin gel with SiO 2, polyvinyl alcohol (PVA) with Prussian blue (PB) mediator and cysteamine self-assembled monolayers (SAM). Then, glucose oxidase (GOD) enzyme was immobilized on the modified surfaces of Pt nanowire electrodes by using techniques of electrochemical adsorption and chemical binding. The GOD immobilized Pt nanowires were used for application in glucose detection by performing a cyclic voltammetry measurement. The detection results showed that GOD was immobilized on all of the tested surfaces and the highest glucose detection sensitivity of 60 μM was obtained when the Pt nanowires were modified by PVA with PB mediator. Moreover, the sensors showed very high current response when the Pt nanowires were modified with the cysteamine SAM. The stability and catalyst activity of GOD are also reported here. For instance, the catalyst activity of GOD retained...
Advances in Natural Sciences: Nanoscience and Nanotechnology, 2011
A diode-pump solid-state laser system emitting a 532 nm beam has been developed. The pump source ... more A diode-pump solid-state laser system emitting a 532 nm beam has been developed. The pump source is an 808 nm diode laser, which has gained wide acceptance in research as well as in commercial production due to its effectiveness and reasonable price. The active medium was chosen to be Nd:YVO 4 (neodymium-doped yttrium orthovanadate), a material with many advantages over traditional Nd:YAG (neodymium-doped yttrium aluminum garnet) such as a low lasing threshold and linearly polarized beam. However, the thermal conductivity of Nd:YVO 4 is not as good as Nd:YAG, thus the thermal lens effect inside Nd:YVO 4 under high pumping intensity becomes severe and detrimental to the laser performance. Our work showed that careful adjustments of Nd:YVO 4 temperature as well as of the cavity's parameters played an important role in the performance of the laser. Potassium titanyl phosphate (KTP), a nonlinear optics crystal, was used to convert the fundamental 1064 nm laser radiation from Nd:YVO ...
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Papers by Mau Nguyen Dang