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A Micromixer Using the Chaos of Secondary Flow: Rotation Effect of Channel on the Chaos of Secondary Flow  [PDF]
Yasutaka Hayamizu, Shinichiro Yanase, Shinichi Morita, Shigeru Ohtsuka, Takeshi Gonda, Kazunori Nishida, Kyoji Yamamoto
Open Journal of Fluid Dynamics (OJFD) , 2012, DOI: 10.4236/ojfd.2012.24A021
Abstract: The micromixer, which has a rotor with a curved channel, is studied experimentally. The secondary flow in a curved channel of rectangular cross-section is investigated using PIV (Particle Image Velocimetry) and LIF (Laser Induced Fluorescence) methods. Two walls of the channel (the inner and top walls) rotate around the center of curvature and a pressure gradient is imposed in the direction of the exit of the channel. The non-dimensional channel curvature δ=a/R is taken to be about 0.1, where 2a is the width of the channel, R the curvature radius of the channel. Other non-dimensional parameters concerned are the Dean number De=Reδ1/2, the Reynolds number Re=qdh/v, where q is the mean flow velocity in the channel axis direction, ν the kinematic viscosity, dh the hydraulic diameter of the channel, and the Taylor number Tr=2(2δ)1/2Ωa2/(δv), where Ω is the angular velocity of the rotor. Photographs of the flow in a cross-section at 180° downstream from the curved channel entrance are taken by changing the flux (De) at a constant rotational speed (Tr) of the channel walls. It is found that good mixing performance is obtained in the case of De≤0.1|Tr| and for that case secondary flows show chaotic behaviors. And then we have confirmed the occurrence of reversal of the mean axial flow.
Dependence Study of Optoelectronics Performance on Carefully Differed LiF Thickness in Alq3 Based OLEDs  [PDF]
Shengxun Su, Changxiao Pan, Xi Luo, Wei Chen, Jiarong Lian
Optics and Photonics Journal (OPJ) , 2013, DOI: 10.4236/opj.2013.32B060

The effect of LiF thickness on the electrical and luminescent characteristics in OLEDs has been studied by carefully varying thickness value range from 0 nm to 1.2 nm. It’s interesting to find that the device with 0.2 nm LiF layer performs the largest current and comparative lower luminescent efficiency, while the one with 0.6 nm LiF performs another current peak (lower than that of device with 0.2 nm LiF layer) but the highest luminescent efficiency in all devices. Here the much enhanced electron injection and destructive efficiency for 0.2 nm LiF device are understood by the chemical interaction model at cathode interface, while the fairly increased electron injection and much improved efficiency for 0.6 nm LiF device would be interpreted by other mechanisms, and LiF plays a protective part in preventing the deposition-induce photoluminescence from quenching by Al cathode.

Determina??o da humifica??o da matéria organica de um latossolo e de suas fra??es organo-minerais
Favoretto, Célia Mara;Gon?alves, Daniele;Milori, Débora M. B. P.;Rosa, Jadir Aparecido;Leite, Wellington Claiton;Brinatti, André Maurício;Saab, Sérgio da Costa;
Química Nova , 2008, DOI: 10.1590/S0100-40422008000800015
Abstract: laser-induced fluorescence spectroscopy was used to determine the humification degree of the organic matter of a whole soil, that is, soil without any physical or chemical treatment. particle size was determined in physically separated fractions. the humification of organic matter, the depth of the soil and the planting system can be correlated. on the surface of the soil, no tillage provided the smallest humification in comparison with the conventional tillage and reduced tillage. the fractions of the superficial layer of the soil (0-20 cm) indicated larger humification in the fraction from 20 to 53 μm and the smallest in the fraction of <2 μm.
Preparation of PES Ultrafiltration Membrane using Novel Modified Microwave Casting Solution Technique
Iqbal Ahmed,Faridah Kormin,Ani Idris,Rosli Bin Mohd Yunus
Journal of Applied Sciences , 2010,
Abstract: In this study the influence of anhydrous lithium fluoride (LiF) and the novel modified microwave casting solution technique on membrane performance are investigated. The polyethersulfone (PES) asymmetric membrane was prepared by the dry/wet phase inversion process. In order to observe the effect of microwave dissolution technique on membrane performance, PES concentration in the dope solutions was kept to 20 wt.% through out the experiments. The concentration of lithium fluoride was varied from 1-5 wt.% and N, N-dimethylformamide (DMF) is used as the solvent. Viscosities of the dope solutions were measured and membrane performance was characterized in terms of pure water permeation (PWP), permeation rate (PR) and solute separation of PEG solutions of different molecular weights ranging from 600-35000 Da. The molecular weight cut off (MWCO), mean pore size and pore size distribution of the membranes were subsequently determined. Results disclosed that the addition of lithium fluoride to the PES/DMF solution and the microwave irradiation technique increases the membrane permeability while maintaining their separation properties. However, the LiF concentration was best kept to 2 wt.% concentration.
Temperature Measurement of Air Flow Using Fluorescent Mists Combined with Two-Color LIF  [PDF]
Shumpei Funatani, Koji Toriyama, Tetsuaki Takeda
Journal of Flow Control, Measurement & Visualization (JFCMV) , 2013, DOI: 10.4236/jfcmv.2013.11004
Abstract: This study proposes a two-color laser-induced fluorescence (LIF) technique for measuring the temperature distribution of an airflow by spraying a mist of a fluorescent dye. The mist is generated by using propylene glycol, the vapor pressure of which is much lower than that of water, as the solvent of the fluorescent dyes. A supersonic moisture chamber is used as the atomizer for seeding the tracer particles to be visualized. The proposed technique is applied to the measurement of the temperature distribution in a thermal vertical buoyant plume. The proposed two-color LIF thermometry is found to be very effective for the study of such a thermal structure, and it is well suited for measuring the temperature field of an airflow.
A Micromixer Using the Taylor-Dean Flow: Effect of Inflow Conditions on the Mixing  [PDF]
Toshihiko Kawabe, Yasutaka Hayamizu, Shinichiro Yanase, Takeshi Gonda, Shinichi Morita, Shigeru Ohtsuka, Kyoji Yamamoto
Open Journal of Fluid Dynamics (OJFD) , 2014, DOI: 10.4236/ojfd.2014.45037
Abstract: Chaotic mixing in a curved-square channel flow is studied experimentally and numerically. Two walls of the channel (inner and top walls) rotate around the center of curvature and a pressure gradient is imposed in the direction toward the exit of the channel. This flow is a kind of Taylor-Dean flows. There are two parameters dominating the flow, the Dean number De (∝ the pressure gradient or the Reynolds number) and the Taylor number Tr (∝ the angular velocity of the wall rotation). In the present paper, we analyze the physical mechanism of chaotic mixing in the Taylor-Dean flow by comparing experimental and numerical results. We produced a micromixer model of the curved channel several centimeters long with square cross section of a few millimeters side. The secondary flow was measured using laser induced fluorescence (LIF) method to examine secondary flow characteristics. We also performed three-dimensional numerical simulations for the exactly same configuration as the experimental system to study the mechanism of chaotic mixing. It is found that good mixing performance is achieved for the case of De ≤ 0.1Tr, and that mixing efficiency changes according to the difference in inflow conditions. The flow is studied both experimentally and numerically, and both results agree with each other very well.
Relevance of LIF and EGF on Mouse Preimplantation Embryo Development
Iraj Amiri,Maryam Prvini,Ali Amini,Khadijeh Heidarbeigi
Cell Journal , 2008,
Abstract: Objective: Recent evidence suggests that Leukemia Inhibitory Factor (LIF), a member ofinterleukin-6 family, has biological actions on preimplantation embryo development. Alsoit is established that Epidermal Growth Factor (EGF), a strong mitosis-promoting agent,improves the preimplantation embryo development by increasing the cell metabolism andproliferation. The purpose of the present study is to investigate the effects of these factors,alone and in combination together, on preimplantation and development of the embryo.Materials and Methods: Six to eight weeks old NMRI mice were super ovulated by injectionof 10IU PMSG and 10IU hCG, then the mated mice were killed 46 hours later. Theiroviducts were flushed, two-cell embryos collected and divided randomly to the four groupsas following: Control, treatment 1 (LIF), treatment 2 (EGF), treatment 3 (LIF+EGF). In eachgroup, the embryos were cultured in an incubator at 37°C with 5% CO2 and 90% humidityfor 72hrs. The state of embryo development was evaluated in 24,36,48,60 and 72hrsfollowing the embryos cultures. By the end of the cultures, cell apoptosis was studiedby the terminal deoxynucleotidyl transferas-mediated dUTP nick end-labeling (TUNEL)technique.Results: Significant difference was detected in the rate of hatching in the LIF and LIF+EGFgroups. This difference was also seen in the rate of blastocyst formation after 36hrs(p<0.05) and in the average of the total cell number (p<0.05) after 72hrs. In comparison tothe apoptotic index, there was no significant difference between the control and treatmentgroups.Conclusion: The findings in this study show a beneficial effect of LIF and EGF on theblastocyst formation, hatching and its total cell numbers in vitro.
Laser induced fluorescence study on the growth of maize plants  [PDF]
Marius Hedimbi, Shyam Singh, A. kent
Natural Science (NS) , 2012, DOI: 10.4236/ns.2012.46054
Abstract: The laser induced fluorescence (LIF) spectra from plants give accurate information on the influences of ultraviolet A (UV-A) and ultraviolet B (UV-B) radiation on the growth of maize plants. In this paper, a thorough LIF study has been done on maize plants grown under controlled conditions. The maize (Zea mays) seeds were planted and exposed to UV-A and UV-B radiation from 0 to10 hours. The decrease in the ratios of peaks of LIF confirm a decrease in the height, diameter of stem, number of leaves in the plants exposed to UV-B and UV-A with the increase in the time of exposure.
Temperature measurements by oh lif and chemiluminescence kinetic modeling for ethanol flames
Marques, Carla S. T.;Santos, Leila R. dos;Sbampato, Maria E.;Barreta, Luiz G.;Santos, Alberto M. dos;
Química Nova , 2009, DOI: 10.1590/S0100-40422009000800017
Abstract: oh lif-thermometry was applied to premixed ethanol flames at atmospheric pressure in a burner for three flame conditions. flame temperatures were simulated from energy equation with premix code of chemkin software package for comparison. a kinetic modeling based on a model validated through chemiluminescence measurements and on a set of reactions for nitrogen chemistry was evaluated. marinov's mechanism was also tested. sensitivity analysis was performed for fuel-rich flame condition with φ = 1.34. simulated temperatures from both reaction mechanisms evaluated were higher than experimental values. however, the proposed kinetic modeling resulted in temperature profiles qualitatively very close to the experimental.
First principles investigation of structural stability and electronic and optical properties of LiF and NaF under high pressure

Li Hai-Ming,Wu Xiang,Li Jiong,Chen Dong-Liang,Chu Wang-Sheng,Wu Zi-Yu,

物理学报 , 2007,
Abstract: First principles calculation of LiF and NaF (NaCl phase and CsCl phase) underhigh pressure was carried out with the full potential linearized augmented plane wave plus local orbital method. It was shown that NaCl-type LiF transforms to a CsCl-type phase at about 450 GPa. Calculations of the electronic properties of LiF at high pressure compared with the energy band structural information indicate that a non-structureal transition occurs at about 53GPa, in which the direct band structure transforms to an in-direct band structure. We also calculated the complex electronic dielectric function and the static dielectric constants of LiF as functions of pressure. The results obtained for LiF are also compared with siilar data of NaF system.
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