• KIEAE Journal
• /
• v.16 no.6
• /
• pp.115-122
• /
• 2016

Purpose: The study is to measure indoor air pollutants concentration of existing housing and to analyze the causes and assess in accordance with the government's criteria. The research result could be used as data for public health through indoor air quality management of existing housing and more as a reference for new housing. Method: It was investigated 24 middle class housings of metropolitan area in summer which have been built for the past 30 years. Concentration of HCHO, TVOC was investigated in living room at morning and night and concentration of $CO_2$ was investigated in living room and master bedroom at morning and night. SKT100-X5 was used for concentration of HCHO, TVOC and ZGm053UK for concentration of $CO_2$. Result: Average concentration of TVOC was 1.31 times more than that of HCHO and standard deviation of that was 1.73 times higher. Average concentration of $CO_2$ was almost nearly close to 1,000ppm being criteria of the Ministry of Environment.

• Journal of Pharmaceutical Investigation
• /
• v.30 no.4
• /
• pp.283-288
• /
• 2000

The purpose of the present study was to investigate the topical bioavailability of retinol (vitamin A) after its transdermal administration. For this purpose, we developed the convenient HPLC method to measure the retinol concentration in the biological fluids such as plasma and skin tissues. The low detection limit was $0.1\;{\mu}g/ml$ using a gradient HPLC system of UV detection. The initial plasma concentration of retinol was about $20\;{\mu}g/ml$ after its i.v. bolus administration (4.32 mg/kg). The half life $(t_{1/2{\alpha}})$ in the distributive phase was 1.3 min, while retinol was slowly disappeared in the post-distributive phase. On the other hand, the maximum plasma concentration $(C_{max})$ was about 776 ng/ml after appling to rat skin at a dose of 43.2 mg/kg. Furthermore, the concentration of retinol in the skin tissues was about 600 ng/g tissue at 12 hr after its transdermal administration. In conclusion, the initial plasma concentration of retinol was comparable with the skin concentration after its cutaneous absorption, followed by being decreased with the passage of the time.

• International Journal of Automotive Technology
• /
• v.7 no.4
• /
• pp.385-390
• /
• 2006

A fast response $CO_2$ analyzer has been developed to study transient characteristics on an SI engine. The analyzer has the delay time of 4.5 ms and time constant of 2.8 ms, which is fast enough to measure $CO_2$ concentration on a transient condition. Wide range of A/F(Air/Fuel) ratio can be estimated using the analyzer with an additional switch type oxygen sensor. The results of measurement of $CO_2$ concentration and A/F ratio on a transient condition including rapid acceleration/deceleration and EGR(Ehxaust Gas Recirculation) on/off are presented and compared with a commercial exhaust gas analyzer and UEGO(Universial Exhaust Gas Oxyzen) sensor.

• International Journal of Oral Biology
• /
• v.30 no.2
• /
• pp.65-69
• /
• 2005

Periodontitis is a multi-microbial disease and the comparison of a series of periodontopathogenic and non-periodontopathogenic bacteria in terms of microbe-host interaction may provide clues to understand the microbial etiology of the disease better. When we deal with twenty different bacterial species in a study, the first technical issue is how to measure the accurate concentration and use the same number of bacterial cells. We measured bacterial concentration by enumerating bacteria stained with SYTOX green for constant time using a flow cytometer and compared the results with those obtained by plate counting. Concentrations calculated by two different methods were very close. Therefore, flow cytometric counting allowed the rapid analysis of live/dead bacteria, offering the advantage of turbidity measurement and that of colony counting together.

• Proceedings of the KSME Conference
• /
• 2004.11a
• /
• pp.1540-1545
• /
• 2004

Measurement of concentration fields in a micro-channel is the crucial technology in the area of Lab-on-a-chip to be used for various bio-chemical applications. It is wel-known that the only possible way to measure the concentration field in the micro-channel is using micro-LIF(Laser Induced Fluorescence) method. However, an accurate concentration field at a given cross plane in a micro-channel has not been made so far due to the limit of light illumination. The present study demonstrates a novel method to provide an ultra thin laser sheet beam having 5 microns thickness by a micro focus laser line generator. Nile Blue A was used as fluorescent dye for LIF measurement. The laser sheet beam illuminates an exact plane of concentration measurement in the micro-channel to increase the signal to noise ratio and reduce the depth uncertainty considerably.

• Agricultural and Biosystems Engineering
• /
• v.1 no.1
• /
• pp.16-21
• /
• 2000

Measurement of spray deposit is necessary for evaluation of a chemical application technology. However it is not easy and time consuming. A simple method for measuring the deposition amount of spray using a tracer and a spectrophotometer was developed. Various materials were tested to determine an adequate tracer. Food dye was selected as a tracer, because it was cheep and easily treatable. Using NIRS(Near Infrared Reflection Spectrophotometer), a regression curves between maximum absorbance of a solution and concentration of the tracer were obtained. Yellow food dye solution showed a peak of spectrum at 452 nm, and absorbance of peak showed a tendency to increase as concentration increased. Green or pink food dye were tested and judged to be good tracers. However, tracer concentration should not exceed certain limits in order to measure maximum absorption. Using spraying liquid with known tracer concentration and known amount of washing liquid, spray deposit amount on real targets on leaves could be estimated at less than 13% error level.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2002.05a
• /
• pp.349-354
• /
• 2002

Significant improvements in bond strength between new and existing concrete can be achieved through the modification of the new concrete by latex modification. But, no test method has been adopted as a standard to measure the bond strength between the concrete used to repair and the substrate being repaired. The performance of old and the new concrete construction depends upon bond strength between old and the new concrete. Current adhesion strength measurement method ignores the effect of stress concentration by shape of specimens. Therefore, this research calculates stress concentration coefficient using finite element analysis and direction tensile strength test (pull-off test). The result shows that the required core depth is 2.5cm. Elastic modulus and overlay thickness do not influence in stress concentration.

• Journal of the Korean Institute of Rural Architecture
• /
• v.13 no.4
• /
• pp.59-66
• /
• 2011

This study aims to understand the degree of inequality of surveyed rural amenity resources according to resources and region in basic self governing body by estimating the Gini Coefficient and Lorenz Curve. Case Study was performed in Sunchang basic self governing body which full survey of rural amenity resources was completed. The Gini Coefficient was applied to measure the concentration of amenity resources in 11 Eup-Myun regions, Sunchang county of Jeonbuk province. The results demonstrate significantly different variation according to Eup-Myun regions and amenity variables. This result would be used as a basic data for rational rural planning based on amenity resources through identifying distributional concentration of rural amenity resources in basic self governing body.

• International Journal of Air-Conditioning and Refrigeration
• /
• v.9 no.1
• /
• pp.20-28
• /
• 2001

In order to predict thermodynamic performance of refrigeration system, it is required to know the oil concentration of the refrigerant/oil mixture. The current method is to extract the working mixture and then to measure the oil weight. In this study, oil concentration is measured in si.tu way without any extraction of the working fluid. Based on the measurement, a working equation is presented as follows, C=a +b x t +c x $t^2$ +(d + e x t +f x $t^2$) x SG. C is oil concentration, t is temperature($^{\circ}C). SG Is specific gravity of mixture and a~f is coefficients The oil concentration ranges over 0~l2 wt% and the temperature ranges over 20~50$^{\circ}C. The specific gravity and temperature are measured using the on-line densimeter and thermometer. This working equation enables to predict the oil concentration without any extraction of the mixture. This equation can be applied for R-12/Naphthenic oil and R-134a/P0E oil liquid mixtures.

• Journal of Environmental Health Sciences
• /
• v.13 no.2
• /
• pp.9-24
• /
• 1987

This study was conducted to measure the diurnal variation and behaviour of atmospheric mercury in an urban area by gold amalgamation and cold vapour atomic absorption spectrophotometry. The results were as follows: 1. The Hg concentration in ambient air averaged. 21.13ng/m$^3$ for 111 determinations (C.V. 78.5) in urban area and 5.91ng/m$^3$ for 140 determinations (C.V. 21.3) in suburban area. The urban area concentration was significantly higher and fluctuated more than its rural counterpart. 2. Regression analysis of the interaction between mercury concentration and other components showed a significant correlation between mercury concentration and sulfur dioxide also, TSP were found. Mercury concentration was shown to have a similar behaviour, on the whole, with other air pollutants. 3. It demonstrated a positive correlation with sunlight (UV-ray), while it had a negative response to wind speed and humidity. Its concentration showed a tendensy to increase during calm weather specifically. 4. The Hg concentration at the Mt. Dok You inland clean area ranged from 1.33ng/m$^3$ to 2.0ng/m$^3$, with a mean value of 1.63ng/m$^3$.