• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.20 no.4
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• pp.217-224
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• 2010

The purity methods to determine LOD/LOQ using standard deviation of the residual, intercept and blank by IUPAC and ACS describe many of the pitfalls and pose significant challenges to analytical chemists. Therefore, the aim of this study is the development of the simple, easy, convenient and statistically significant method to determine LOD in quantitative analysis of organic solvents by GC. The new approaching method by linearization in the given concentration range used coefficient of variation ; ${\sigma}_{n-1}$/S(standard deviation, ${\sigma}_{n-1}$ and average, S) of sensitivity(Response/concentration). The comparison of results among the purity methods(IUPAC and ACS) and the linearization have been fulfilled the F-test for standard deviations and t-test for LOD range values. The results of F-test and t-test are satisfied within 95 % confidence level, respectably. The LOD values determined by the new procedure are n-Hexane 0.0116 mg/$m^3$, Toluene 0.0807 mg/$m^3$, and o-Xylene 0.0494 mg/$m^3$. Because the standard deviation of the residual, intercept and blank and the slope of calibration curve are not calculated and the new approaching method use the coefficient of variation of sensitivity by linearization, this new method is simple, easy, convenient and statistically significant. In future, many chemical analysts will expect to applicate and routinely use this method in the all quantitative analysis.

• The Korean Journal of Zoology
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• v.35 no.2
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• pp.219-225
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• 1992

The genetic variation in mitochondrial DNA (mtDNA) was analysed within and between two species of tree frogs. Hyla japonica and H. suweonensis from South Korea. Purified mtDNAs were digested with each of 11 restriction enLvmes which cleave at six base recognition sequences. The genome size of H. iaponica revealed ho types (20.0 $\pm$ 0.3 and 19.6 $\pm$ 0.3 kb) and this difference is explained by either addition or deletion of about 0.4 kb fragment. On the other hand, the genome sire of H. suueonensis was about 19.0 $\pm$ 0.4 kb only. For the analysis, level of fragment homology (F) and nucleotide sequence divergence (p) were estimated from comparisons of digestion profiles. Among four populations of H. iaponica, substantial mean sequence divergence was 0.017 (range 0.001-0.026); between identical types, 0.001 IslilaRl type) and 0.004 (Large type) respectively; between different ones, 0.024 (range 0.023-0.026). The level of sequence divergence between he species was 0.142 (range 0.131-0.146). This result suggested that he species ㅂwere distinctly differentiated species. The divergence time between ko species was estimated 7.1 million years.

• Ocean and Polar Research
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• v.28 no.4
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• pp.395-405
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• 2006

We measured the fugacity of $CO_2$ $(fCO_2)$, temperature, salinity, nutrients and chlorophyll a in the surface water of the western North Pacific $(4^{\circ}30'{\sim}33^{\circ}10'N,\;144^{\circ}20'{\sim}127^{\circ}35'E)$ in September 2002. There were zonally several major currents which have characteristics of specific temperature and salinity (NECC, North Equatorial Counter Current; NEC, North Equatorial Current; Kuroshio etc.). Surface $fCO_2$ distribution was clearly distinguished into two groups, tropical and subtropical areas of which boundary was $20^{\circ}N$. In the tropical Int surface $fCO_2$ was mainly controlled by temperature, while in the subtropical area, surface $fCO_2$ was dependent on total inorganic carbon contents. Air-sea $CO_2$ flux showed a large spatial variation, with a range of $-0.69{\sim}0.79 mmole\;m^{-2}day^{-1}$. In the area of AE (Anticyclonic Eddy), SM(Southern Mixed region) and NM (Northern Mixed region), the ocean acted as a weak source of $CO_2$ $(0.6{\sim}0.79 mmole\; m^{-2}day^{-1})$. In NECC, NEC, Kuroshio and ECS (East China Sea), however, the fluxes were estimated to be $-0.3mmole\; m^{-2}day^{-1})$ for the first three regions and $-1.2mmole\; m^{-2}day^{-1})$ for ECS respectively, indicating that these areas acted as sinks of $CO_2$. The average air-sea flux in the entire study area was $0.15mmole\;m^{-2}day^{-1})$, implying that the western North Pacific was a weak source of $CO_2$ during the study period.

• Fisheries and Aquatic Sciences
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• v.11 no.2
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• pp.98-102
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• 2008

Relationships between total length (TL) and fecundity, body weight and fecundity, ovary length and fecundity, and ovary weight and fecundity of hilsa shad, Tenualosa ilisha Hamilton, collected from Kuakata, Patuakhali, Bangladesh, were studied. During the sampling period, the fecundity of hilsa was found to range from 169,000 (fish TL=28.0cm, weight=250g) to 1,088,000 (fish TL=40.5cm, weight=955g) with a mean of $520{\pm}53{\times}1,000$. The number of eggs per gram of ovary for samples collected from the anterior, middle, and posterior regions of the ovary were also recorded, but no significant variation was found among ovary regions at the 5% level of significance. Fecundity increased with fish TL and weight. The regression equations obtained in arithmetic forms of relationships between TL and fecundity (F), body weight (BW) and fecundity, ovary length (OL) and fecundity, and ovary weight (OW) and fecundity were $F=-887,896+40,511{\times}TL(r=0.85)$, $F=67,577+755.44{\times}BW(r=0.85)$, $F=-562,070+87,668{\times}OL(r=0.75)$ and $F=124,815+6,596.7{\times}OW (r=0.84)$, respectively. The relationships between fecundity and TL, body weight, ovary length, and ovary weight were linear, and the 'r' values were highly significant (p<0.01). These results provide valuable data for the restoration of hilsa resources, which are economically important but have shown reduced productivity in nations adjacent to the Bay of Bengal.

• Journal of the korean academy of Pediatric Dentistry
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• v.41 no.3
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• pp.218-224
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• 2014

This study was designed to evaluate the effectiveness of 5% sodium fluoride-polyvinyl alcohol (NaF-PVA) tape influencing enamel remineralization by analysing enamel surface microhardness (SMH) and variation of ${\Delta}F$ of QLF. After enamel demineralizing of specimen, these 60 specimens with average KHN of microhardness ranging from 50 to 100 and with ${\Delta}F$ of QLF ranging from -15 to -25 were divided into four groups : group 1 (control group), group 2 (NaF-PVA), group 3 (fluoride varnish, FluoroDose$^{(R)}$ varnish), group 4 (Casein phosphopeptide-amorphous calcium phosphate, Tooth mousse plus$^{TM}$). These specimens were treated with materials and then immersed in artificial saliva. We measured remineralization rate each using surface microhardness (SMH) and Quantitative light-induced fluorescence digital (QLF-D). As a result, NaF-PVA tape is better than group 1, 4 and have comparable remineralization effect with group 3 (p < 0.05).

• Phonetics and Speech Sciences
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• v.9 no.3
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• pp.85-91
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• 2017

The present study aimed to investigate the changes of acoustic parameters of the aspirated voice in stroke patients. The eighty-eight subjects diagnosed with cerebro-vascular accident were divided into 32 penetration/aspiration (P/A) and 56 Non-P/A groups according to the videofluroscopic swallowing study (VFSS) results, and 26 control subjects participated. All subjects preformed VFSS and vowel /a/ was recorded three times pre- and post VFSS. Since the variation in the acoustic parameters within a single phonation has been observed, we proposed a delta formula for the acoustic parameters which can reflect the temporal changes of the each parameter in an utterance. We measured from the voice data eight acoustic parameters: fundamental frequency (F0), standard deviation of F0 (F0_SD), Jitter, relative average perturbation (RAP), Shimmer, amplitude perturbation quotient (APQ), harmonic to noise ration (HNR), noise to harmonic ratio (NHR). Then we found parameters which show the meaningful biggest temporal change in an utterance using the suggested delta parameter. Among them, the deltas of shimmer and APQ were significantly different pre- and post VFSS. These deltas of the P/A and the control group were increased after VFSS, while those of the Non-P/A group was descended. The variation patterns of the P/A and the control group were similar but the change width of the P/A group was larger. The large variations in an aspirated phonation of the P/A group are thought to be caused by irregular changes in air resistance due to residual food on the vocal cords.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.5
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• pp.495-498
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• 1995

Records taken on 372 young beef bulls tested at the Ellerslie Bull Test Station, Alberta, Canada from November 1981 to April 1987 were analyzed to quantify the effects of age of dam, on-test age, on-test liveweight and herd of origin of bull on feed efficiency (feed/gain, kg/kg) in the test period (n = 231) and ultrasonic measurement of bakcfat thickness (mm) at the end of the test (n = 372). The reduction in $R^2$ due to each influencing factor (i.e. the variation accounted for by the factor) was used to indicate the importance of the influencing factor. Age of dam and on-test age of bull were not important factors on feed/gain and ultrasonic backfat thickness, as they accounted for less than 0.5% of the variation in feed/gain and ultrasonic backfat thickness, respectively (p > 0.1). On-test liveweight had some influence on feed/gain and ultrasonic backfat thickness, accounting for 3.5% (p < 0.01) and 0.4% (p < 0.05) of the total variation, respectively. The regression coefficients of feed/gain and ultrasonic backfat thickness on on-test liveweight were 0.016 (kg/kg)/kg and .013 mm/kg, respectively, both being significant (p < 0.05), indicating that lighter bulls entering the test were generally more efficient in feed utilization in the test period and had less backfat at the end of the test than heavier entering bulls. Herd of origin of bull accounted for a substantial amount of the total variation (> 16%) in feed/gain and ultrasonic backfat thickness (p = 0.08), indicating that a prolonged aqjustment period was needed to reduce the influence of herd of origin when assessing aggregate genetic merit of beef bulls for growth rate, feed efficiency and lean meat production using a central station performance testing program.

• Nuclear Engineering and Technology
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• v.43 no.1
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• pp.83-88
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• 2011

To define the effect of strain rate variation from 0.04% to 0.004%/s on environmental fatigue of CF8M cast stainless steel, which is used as a primary piping material in nuclear power plants, low-cycle fatigue tests were conducted at operating pressure and temperature condition of a pressurized water reactor, 15 MPa and $315^{\circ}C$, respectively. A high-pressure and high-temperature autoclave and cylindrical solid fatigue specimens were used for the strain-controlled low-cycle environmental fatigue tests. It was observed that the fatigue life of CF8M stainless steel is shortened as the strain rate decreases. Due to the effect of test temperature, the fatigue data of NUREG-6909 appears a slightly shorter than that obtained by KEPRI at the same stress amplitude of $1{\times}10^3$ MPa. The environmental fatigue correction factor $F_{en}$'s calculated with inputs of the test data increases with high strain amplitude, while the $F_{en}$'s of NUREG-6909 remain constant regardless of strain amplitude.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.5
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• pp.616-624
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• 2011

The flow characteristics and heat transfer augment on the periodically arranged semi-circular ribs in a rectangular channel for turbulent flow has been investigated numerically. The aspect ratio of the rectangular channel was AR=5, the rib height to hydraulic diameter ratio were 0.07 and rib height to channel height ratio was set as e/H=0.117 for various PR(rib pitch-to-rib height rate) between 8~14, respectively. The SST k-${\omega}$ turbulence model and v2-f turbulence model were used to find out the heat transfer and the flow characteristics of near the wall which are suited to obtain realistic phenomena. The numerical analysis results show turbulent flow characteristics, heat transfer enhancement and friction factor as observed experimentally. The results predict that turbulent kinetic energy(k) is closely relative to the diffusion of recirculation flow. and v2-f turbulence model simulation results have a good agreement with experimental values.

• Korean Journal of Optics and Photonics
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• v.9 no.3
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• pp.168-174
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• 1998

We have measured nonlinear refractive index and nonlinear absorption coefficient of optical materials by using a far-field phase modulation technique. The phase variation of the probe beam in the nonlinear material is transformed into the spatial phase modulation in the far-field so that the spatial distribution of the optical intensity in conjunction with the computer simulation analysis can give the nonlinear optical constants. We have obtained the nonlinear refractive indices and nonlinear absorption coefficient of $CS_2$ and $BaF_2$ by fitting the experimental values and numerical simulation analysis of far-field measurements. The nonlinear refractive indices of $CS_2$ and $BaF_2$were obtained as $1.2{\times}10^{-11}$ esu and $1.0{\times}10^{-13}$ esu, respectively at 616 nm, and the nonlinear absorption coefficient of BaF$_2$as $5.0{\times}10^{-11}$cm/W at 308nm. These measured values were in good agreement with previous reports.