• Journal of Advanced Marine Engineering and Technology
• /
• v.28 no.8
• /
• pp.1211-1224
• /
• 2004

Two round jets. impinged and pulsed. were measured with high-resolution 3D-PTV technique. The measurement system consists of three CCD cameras, Ar-ion laser, an image grabber and a host computer. Two fitness functions were introduced in a genetic algorithm in order to enhance the correspondences of the particles. One was based on a concept of the continuum theory and the other one was based on a minimum distance error. The velocity profiles of the impinged jet obtained by the constructed 3D-PTV system were compared with those of LDV measurements made in this study. The head vortex of the jet was visualized by LIF and was reconstructed by the constructed high-resolution 3D-PTV system for comparisons.

• Korean Journal of Medicinal Crop Science
• /
• v.10 no.4
• /
• pp.237-242
• /
• 2002

It was found that the purified extract from A. gigas Nakai (polysaccharide, M.W., 25 kD) controled differentiating human ES cells. Its optimal supplementation concentration was decided as 0.8 $({\mu}g/ml)$ to efficiently control the differentiation. It also enhanced the cell growth, compared to the control. However, most widely used and commercially available differentiating agent, Leukemia Inhibitory Factor (LIF) negatively affected on the cell growth even though it controls the differentiation of ES cells, down to 40-50 % based on morphological observation and telomerase activity. It was presumed that the extract first affected on cell membrane and resulted in controlling signal system, then amplify gene expression of telomere, which enhanced the telomerase activity up to three times compared to the control. LIF only increased the enzyme activity up to two times. It was confirmed that the extract from A. gigas Nakai could be used for substituting currently used differentiation controlling agent, LIF from animal resources as a cheap plant resource and not affecting the cell growth. It can broaden the application of the plants not only to functional foods and their substitutes but also to fine chemicals and most cutting-edge biopharmaceutical medicine.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.20 no.2
• /
• pp.710-719
• /
• 1996

Laser applied combustion diagnostic techniques-laser induced fluorescence (LIF) and coherent anti-Stokes Ramann spectroscopy (CARS)-are demonstrated. The profiles of hydroxyl radical (OH) and temperature in the counterflow burner are measured and compared with the numerical results. OH radical is excited on the Q$_1$(6) line of the $A^2$$\sum^+$$\leftarrow$$X^2{\prod}$(1, 0) band transition (281.1 nm) and LIF signal is measured at the the bands of (0, 0) and (1, 1) transition (306~326 nm). Absolute OH radical is obtained by using the laser absorption technique. The quenching effects are considered. Temperature is measured using broadband CARS system. Two dimensional OH radical profile is also obtained. The profiles of OH radical and temperature are found to agree well with those of numerical calculation.

• Journal of the Korean Society of Visualization
• /
• v.10 no.1
• /
• pp.34-39
• /
• 2012

In the present study, oxygen transfer process across gas-liquid interface in a Y-shape micro-channel is quantitatively visualized using the micro laser induced fluorescence (${\mu}$-LIF) technique. Diffusion coefficient of Oxygen ($D_L$) is estimated based on the experimental results and compared to its theoretical value. Tris ruthenium (II) chloride hexahydrate was used as the oxygen quenchable fluorescent dye. A light-emitting diode (LED) with wavelength of 450 nm was used as the light source and phosphorescence images of fluorescent dye were captured by a CMOS high speed camera installed on the microscope system. Water having dissolved oxygen (DO) value of 0% and pure oxygen gas were injected into the Y-shaped microchannel by using a double loading syringe pump. In-situ pixel-by-pixel calibration was carried out to obtain Stern-Volmer plots over whole flow field. Instantaneous DO concentration fields were successfully mapped according to Stern-Volmer plots and DL was calculated as $2.0675{\times}10^{-9}\;m^2/s$.

• 한국가시화정보학회:학술대회논문집
• /
• 2002.11a
• /
• pp.43-44
• /
• 2002

A pulsed jet was measured with high-definition 3D-PTV technique. The measurement system consists of three CCD cameras, Ar-ion laser, an image grabber and a host computer. Two fitness functions were introduced in a genetic algorithm in order to enhance the correspondences of the particles. One was based on a concept of the continuum theory and the other one was based on a minimum distance error. The head vortex of the jet was visualized by LIF and was reconstructed by the constructed high-resolution 30-PTV system for comparisons.

• Development and Reproduction
• /
• v.13 no.1
• /
• pp.1-11
• /
• 2009

Implantation itself is governed by an array of endocrine, paracrine and autocrine modulators, of embryonic and maternal origin. Window of implantation is the unique temporal and spatial expression of factors allows the embryo to implant via signaling, appositioning, attachment, and invasion in a specific time frame of $2{\sim}4$ days. When the embryo has arrived in the uterine cavity, a preprogrammed sequence of events occurs, which involves the production and secretion of a multitude of biochemical factors such as cytokines, growth factors, and adhesion molecules by the endometrium and the embryo, thus leading to the formation of a receptive endometrium. Cytokines such as LIF, CSF-1, and IL-1 have all been shown to play important roles in the cascade of events that leads to implantation. Integrin, L-selectin ligands, glycodelin, mucin-1, HB-EGF and pinopodes are involved in appositioning and attachment. The embryo also produces cytokines and growth factors (ILs, VEGF) and receptors for endometrial signals such as LIF, CSF-1, IGF and HB-EGF. The immune system and angiogenesis play an important role. The usefulness of these factors to assess endometrial receptivity and to estimate the prognosis for pregnancy in natural and artificial cycles remains to be proven. Integrins, pinopodes, glycodelin and LIF (from biopsies) are promising candidates; from uterine flushings, glycodelin and LIF are also candidates. The ideal serum marker is not available, but VEGF, glycodelin and CSF have some clinical implications. Further evaluation that includes larger groups of infertile women and fertile controls are needed to elucidate whether their presence in plasma, flushing fluid, or endometrial samples can be used as some kind of a screening tool to assess endometrial function and prognosis for pregnancy before and after artificial reproductive therapy. A better understanding of their function in human implantation may lead to therapeutic intervention, thereby improving the success rate in reproduction treatment. New molecular techniques are becoming available for measuring both embryonic and endometrial changes prior to and during implantation. The use of predictive sets of markers may prove to be more reliable than a single marker. Ultimately, the aim is to use these tools to increase implantation in artificial cycles and consequently improve live-birth rates.

• Particle and aerosol research
• /
• v.13 no.1
• /
• pp.25-31
• /
• 2017

This paper offer the characteristics for the detection and classification of biological and non-biological aerosol particles in the air by using laser-induced-fluorescence (LIF) based Bio-aerosol Detection System (BDS). The BDS is mainly consist of an optical chamber, in-outlet nozzle system, 405 nm diode laser, an avalanche photo detector (APD) for scattering signal and photomultiplier tubes (PMT) for fluorescence signals in two different wavelength range ; F1, 510-600 nm and F2, 435-470 nm. The detection characteristics, especially ratio of fluorescence signal intensity were examined using well-known components : polystylene latex (PSL), fluorescence PSL, $2{\mu}m$ of SiO2 micro sphere, dried yeast, NADH, ovalbumin, fungicide powder and standard dust. The results indicated that the 405 nm diode laser-based LIF instrument can be a useful bio-aerosol detection system for unexpected biological threaten alter in real-time to apply for dual-use technology in military and civilian fields.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.18 no.1
• /
• pp.55-60
• /
• 2012

In order to investigate the effect of n-heptane mixing on PAH and soot formation, small amount of n-heptane has been mixed in counterflow ethylene diffusion flame. Laser-induced incandescene and laser-induced fluorescene techniques were employed to measure soot volume fraction and polycyclic aromatic hydrocarbon(PAH) concentration, respectively. Results showed that the mixing of n-heptane in ethylene diffusion flame produces more PAHs and soot than those of pure ethylene flame. However, signals of LIF for 20% n-heptane mixture flame were lower than that of pure ethylene flame. It can be considered that the enhancement of PAH and soot formation by the n-heptane mixing of ethylene can be explained by methyl($CH_3$) radical in the low temperature region. And it can be found that reaction rate of H radical for 10% n-heptane plays a crucial role for benzene formation.

• Bulletin of the Korean Chemical Society
• /
• v.23 no.2
• /
• pp.184-188
• /
• 2002

Unsaturated $Cr(CO)_x(1{\leq}x{\leq}5)$molecules were generated in the gas phase from photolysis of $Cr(CO)_6$vapor in He using an unfocussed weak UV laser pulse and their reactions with $O_2$ and $N_2O$ have been studied. The formation and disappearance of the ground state CrO molecules were identified by monitoring laser-induced fluorescence(LIF) intensities vs delay time between the photolysis and probe pulses. The photolysis laser power dependence as well as the delay time dependence of LIF intensities from the CrO orange system showed different behavior as those from ground state Cr atoms, suggesting that the ground state CrO molecules were generated from the reaction between $O_2/N_2O$ and photo-fragments of $Cr(CO)_6$ by one photon absorption. The depletion rate constants for the ground state CrO by $O_2$ and $N_2O$ are $5.4{\pm}0.2{\times}10^{-11}$ and $6.5{\pm}0.4{\times}10^{-12}cm^3molecule^{-1}s^{-1}$, respectively.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.18 no.5
• /
• pp.817-826
• /
• 2023

In this paper, a fault determination methodology based on an artificial neural network was proposed to protect the system from faults on the lines in the smart grid distribution system. In the proposed methodology, first, it was designed to determine whether there is a low impedance line fault (LIF) based on the magnitude of the current RMS value, and if it is determined to be a normal current, it was designed to determine whether a high impedance ground fault (HIF) is present using Normal/HIF classifier based on artificial neural network. Among repetitive DSP module-based algorithm verification tests, the normal/HIF classifier recognized the current waveform as normal and did not show reclosing operation for the cases of normal state current waveform simulation test where the RMS value was smaller than the minimum operating current value. On the other hand, for the cases of LIF where RMS value is greater than the minimum operating current value, the validity of the proposed methodology could be confirmed by immediately recognizing it as a fault state and showing reclosing operation according to the prescribed procedure.