• Proceedings of the SCSK Conference
• /
• 2003.09b
• /
• pp.528-528
• /
• 2003

The present study was undertaken to develop the in vitro sun protection factor(SPF) test method having good correlation with in vivo method using human. 8% homomentyl salicylate, P3 reference standard and commercially available sunscreen products were measured by the in vitro method using SPF 290S analyzer, and the SPFs were compared with the SPFs measured by in vivo test method. In vitro SPFs of 8% HMS and P3 reference standard were 4.59 $\pm$ 0.12 and 14.94 $\pm$ 0.83. There are good correspondence, correlation coefficients were 0.9506 and 0.9769 respectively, between the in vitro and in vivo SPFs for the sunscreen creams and lotions. Correlation coefficients of makeup base/liquid foundation, lotion labled with "shake before use" and compact powder were 0.8812, 0.8632 and 0.5984 respectively. The optimum mixture ratio of compact powder and cream base represents 1:0.8. These results suggest that the in vitro SPF test method will be able to be used as an alternative method for in vivo SPF in case of lotion and cream.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.26 no.1
• /
• pp.88-95
• /
• 1999

구강내의 교정 장치는 미생물 전파에 있어서 다양한 장소를 제공한다. 치태는 치아 우식증 발생에 있어 매우 큰 역할을 하며 미생물, 비세포성 물질로 구성되어 있다. 본 연구의 목적은 생체외에서 교정용에서의 인공 치태 생성에 영향을 주는 요인을 평가하는 것이다. Streptococcus mutans type c는 $CO_2$ incubator내의 $37^{\circ}C$에서 brain heart infusion broth에서 배양 되었다. 중절치에 사용하는 9개의 $.018"{\times}.025"$ standard edgewise brackets을 3개씩 비이커의 배양액에 매달았다. 3개 비이커의 배양액 pH는 각 각 pH 5.5, 7.0 그리고 8.5로 조절되었다. 5시간 후에 비이커에서 각각의 bracket을 꺼내서, bracket의 평균 무게를 측정하였다. 배지의 stirring effect를 측정하기 위하여 3개씩 $.018"{\times}.025"$ standard edgewise brackets을 2개의 비이커에 위치시켰다. 12개의 brackets을 $CaCl_2$(0.25, 1.0, 4.0 그리고 16.0mM). KCl(2.5, 10, 40 그리고 160mM) 그리고 $MgCl_2$(0.1, 0.4, 1.6, 그리고 6.4mM) 용액에 각각 매달았다. 6개의 $.018"{\times}.025"$ standard edgewise brackets, 6개의 $.022"{\times}.028"$ Roth brackets과 6개의 $.022"{\times}.028"$ Broussard brackets을 각각의 비이커 내에 매달았다. 배양액 내에서 5시간 동안 배양한 후 각각의 brackets을 근사값의 milligram 단위로 측정하였다. 그룹 사이의 차이는 Mann-Whitney와 Kruskal-Wallis tests를 이용하여 비교하였다. p value<0.05의 조건에서 이들의 차이는 통계학적 유의성을 갖는다. 5시간 동안 pH 5.5에서 배양된 Streptococcus mutans에 의해 형성된 인공 치태는 pH 7.0 이나 pH 8.5에서 배양된 것보다 작았다(p<0.05). 인공 치태는 배양하는 동안 저어졌을 때 더 많이 형성되었다(p<0.05). 결론적으로 bracket에 형성된 인공 치태는 좀 더 높은 알칼리성 배지에서 배양됨으로써, 그리고 배양 동안 배지를 저어줌으로써 유의성있게 증가하였다. 그러나 배지의 $CaCl_2,\;KCl,\;MgCl_2$의 농도와 상업적으로 다른 종류의 이용 가능한 교정용 bracket에 대해서는 유의한 차이가 없었다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2006.04a
• /
• pp.402-406
• /
• 2006

The physical and chemical characteristics of ALC were analyzed and showed 2.2 of specific gravity and 9.05 of pH. The results of leaching tests with standard method for soil and waste indicated heavy metals(Cu, Cd, Pb, $Cr^{6+}$) were under maximum concentration level. The anaerobic digestion sludge was attached in the surface of ALC within 90 hours. As the results of batch test, pH of the ALC and Bio-ALC were decreased from initial pH of ALC to 8.7 and 7.8 respectively Also, the concentration of heavy metals was rapidly eliminated in the solution with the batch test. The result of column experiment indicates that the removal efficiency of ALC was showed 66% of T-P, 60% of T-N, and 67% of CODcr. Also, removal efficiency of Bio-ALC was slightly higher than that of ALC in T-N (64%) and CODcr (74%).

• Journal of the Korean Academy of Clinical Electrophysiology
• /
• v.1 no.1
• /
• pp.1-15
• /
• 2003

The purpose of this study was to determine the effect of neuromuscular electrical stimulation(NMES) on the alteration of spinal motor neuron excitability. In this article, I would like to experiment on a standard capacity of clinical electrophysiology, a difference in applying methods and a clinical efficiency of NMES by Nerve conduction velocity. We used normal eight subjects without neuromuscular disease and all subjects participated 3 session, which at least 1 week between session. Participants classified according to each group in Antagonist, Agonist, Antagonist-Agonist by the NMES. The test was measured continuously pre test, post-test, post 20 minute test by EMG including H reflex, F wave, motor nerve conduction velocity(MNCV). The following results were obtained; 1. H-reflex latencies and H/M intervals were significantly increased in agonist and antagonist-agonist group(p<.01). 2. H-reflex amplitudes and H/M ratios were significantly decreased in agonist and antagonist-agonist group(p<.01). In agonist group, H-reflex amplitudes and H/M ratios were more significantly decreased than antagonist group. 3. F-wave latencies were significantly increased in agonist and antagonist-agonist group(p<.01). F/M intervals were significantly increased in antagonist-agonist group(p<.01). F wave conduction velocities were significantly increased in agonist and antagonist-agonist group(p<.01) but F/M ratios were not significant. 4. MNCV were significantly decreased in agonist(p<.01). These results lead us to the conclusion that agonist and Antagonist-agonist was significantly decreased excitability of spinal motor neuron. Conversely, Antagonist does not decreased. Therefore, A further direction of this study will be to provide more evidence that NMES have an effect on excitability of spinal motor neurons in UMN syndrome.

• Corrosion Science and Technology
• /
• v.6 no.5
• /
• pp.257-260
• /
• 2007

In order to further improve the corrosion resistance and wear resistance of the Ni-P coatings of electroless plating, electroless Ni-P/n-$Al_2O_3$ composite deposits were prepared by adding some nano $Al_2O_3$ Particles in Ni-P plating bath. The bath composition and proproties were studied in this paper. The orthogonal test was applied in order to get the new composite solution, taking the initial stable potential as evaluation standard and considering the elements correlation at the same time. The processing parameters have been optimized by single factor experiment in which the depositing speed was chosen as the evaluation standard. The results showed that the process is stable and the composite Ni-P/n-$Al_2O_3$ deposits werebright and smooth, whose hardness and corrosion resistance are much better than simple Ni-P coatings. Furthermore the surface appearance and structure of the composite Ni-P/n-$Al_2O_3$ coating were investigated by SEM and XRD method. It was proved that the coating surface is typical cystiform cells and its structure is amorphous. All test results ofcomposite coating showed that all various physical coating properties had been improved by adding nano-particles. The hardness of optimal coating is more than 600HV and increases to 1000HV after heat-treating, and its hardness is 20~50% higher than Ni-P coating. The rust points appeared in 200 hour by immersing the coating into the 10%HCl solution and the corrosive speed is $3{\times}10^{-3}mg/(cm^2{\cdot}h)$which was obtained after 300 hour. In the same condition Ni-P coating is $5.6{\times}10^{-3}mg/(cm^2{\cdot}h)$. The salt spray resistance of the layers can exceed 600h with the thickness $20{\mu}m$.

• Journal of the Korean GEO-environmental Society
• /
• v.7 no.6
• /
• pp.121-131
• /
• 2006

This study is performed to examine the ground reinforcement effect and the environmental impact of LW injection, which is widely used during the excavation of high-rise apartment buildings. In addition, it proved that by conducting field exploration and laboratory test the engineering ground reinforcement effect of LW injection in the ground has low coefficient of permeability. The environmentally friendly aspect was evaluated through an assessment of environmental impact. The results of laboratory test shows that LW coagulating material with SC type soil structure has significant improvement of uniaxial compressive strength, increasing by three times and the shear strength increasing by twice, coefficient of permeability decreasing six to seven times. And the result of environmental impact tests show that from 6 hour after where the pH increases until 7.96 to initially it diminished, it started and to 80 hour after it recovered a pH 7.25 initially with 7.30. The chemical composition analysis test result that unpolluted water and polluted water hydrogen ion concentration (pH) show that the unpolluted water pH 7.36, polluted water pH 7.85, which is inside the Ministry of Environment standard of drinking water (the pH 5.8~8.5). The assessment of environmental impact and chemical analysis test also demonstrate that the LW coagulating material is environmentally friendly. In the $Cr^{6+}$ and the salinity detection test, it was proven that the salinity is slight and the $Cr^{6+}$ is not detected.

• Proceedings of the KIEE Conference
• /
• 2002.11a
• /
• pp.34-36
• /
• 2002

The objective of this study is to develop the composite insulator for 170kA disconnecting switch. In this paper, we have investigated the test procedure about each component(FRP tube, flange, shed) through technical standard(IEC 61462) and obtained demand characteristics by mechanical & electrical property test.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 1998.11a
• /
• pp.156-161
• /
• 1998

As grouting materials for ground improvement, silicate materials such as water glass, silica-sol and so forth are used worldwide. However, they may pollute underground water. In this study, fish poison test(Korean standard industrial code KS M 0111) which estimates toxicity for fish is applied to evaluate the toxic effect by grouting materials. From the test result of the sample made of LW, LC50(Median Lethal Concentration) reaches within 24 hours. In case of the silica-sol, it does not even in 96 hours. Therefore, we can conclude that the sililca-sol grouting method is more free from the danger of underground water pollution. From the result that the mortality of fish under the condition of pH 8.6 is 0% within 96 hours, the groundwater can be saved by controlling pH below 8.6 for the grouting in the field.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
• /
• v.18 no.2
• /
• pp.102-107
• /
• 2007

Laryngopharyngeal reflux disease (LPRD) is the result of retrograde flow of gastric contents to the laryngopharynx. Laryngoscopic findings and special questionnaires are first step of diagnosis of LPRD. Empiric trials of Proton pump inhibitor' test (PPI test) is recommended as treatment and diagnosis. However confirmation of reflux is then recommended primarily in patients with persistent symptoms despite acid-suppressive therapy. The 24 hour ambulatory double pH monitoring has been a gold standard method in diagnosis of LPRD even though it has some limitation. The combined multichannel intraluminal impedance and pH monitoring is a new-rising test tool. It can detect acid/non-acid, liquid/gaseous reflux and clearance of refluxate. The water siphon test is also used for diagnosis of LPRD.

• Animal Bioscience
• /
• v.35 no.1
• /
• pp.147-152
• /
• 2022

Objective: This study was conducted to obtain an objective index that can be quantified and used for establishing an animal welfare certification standard in Korea. For this purpose rumen pH, ruminating time, milk yield, milk quality, and blood components of cows reared in farms feeding high forage level (90%) and farms feeding low forage level (40%) were compared. Methods: Data on rumen pH, rumination time, milk yield, milk fat ratio, milk protein ratio, and blood metabolism were collected from 12 heads from a welfare farm (forage rate 88.5%) and 13 heads from a conventional farm (forage rate 34.5%) for three days in October 2019. Results: The rumination time was longer in cattle on the welfare farm than on the conventional farm (p<0.01), but ruminal pH fluctuation was greater in the cattle on conventional farm than the welfare farm (p<0.01). Conventional farms with a high ratio of concentrated feed were higher in average daily milk yield than welfare farms, but milk fat and milk production efficiency (milk fat and milk protein corrected milk/total digestible nutrients) was higher in cattle on welfare farms. Blood test results showed a normal range for both farm types, but concentrations of total cholesterol and non-esterified fatty acid were significantly higher in cows from conventional farms with a high milk yield (p<0.01). Conclusion: The results of this study confirmed that cows on the animal welfare farm with a high percentage of grass feed had higher milk production efficiency with healthier rumen pH and blood metabolism parameters compared to those on the conventional farm.