• Journal of Environmental Health Sciences
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• v.47 no.4
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• pp.303-309
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• 2021

Background: Humidifier disinfectant is a biocidal product used in the water tanks of humidifiers to prevent the growth of microorganisms. Although there are a huge number of cases of reported humidifier disinfectant-related health effects across the entire Korean population, their numbers are distributed differently depending on the region. Objectives: This study aimed to investigate the regional distribution of enrollment cases who reported humidifier disinfectant-related health effects. Methods: This study used data on 6,240 subjects who experienced humidifier disinfectant-related health effects and who enrolled their cases which is conducted by the Korea Ministry of Environment. We examined the regional distribution of the enrolled cases based on sixteen administrative divisions and assessed the: 1) crude number; 2) proportional rate; and 3) age-standardized proportional rate of enrollment by region. Results: When we examined the crude number of enrollments by region, the highest number were in Gyeonggi-do Province (n=1,896), followed in order by Seoul (n=1,405), Incheon (n=436) Busan, Daegu, Gyeongsangnam-do Province, Daejeon, Chungcheongnam-do Province, Gyeongsangbuk-do Province, Jeollabuk-do Province, Gwangju, Chungcheongbuk-do Province, Gangwon-do Province, Jeollanam-do Province, Ulsan, and Jeju-do. When we examined proportional rate of the regional enrollment (cases per 100,000 population), Daejeon (n=16.2) was the region with the highest rate, followed in order by Gyeonggi-do Province (n=16.1), Incheon-do Province (n=15.9), Seoul, Daegu, Gwangju, Jeollabuk-do Province, Chungcheongnam-do Province, Busan, Chungcheongbuk-do Province, Gangwon-do Province, Gyeongsanbuk-do Province, Gyeongsangnam-do Province, Ulsan, Jeju-do, and Jeollanam-do Province, which is inconsistent with the order in terms of crude numbers. However, when we examined the age-standardized proportional rate of regional enrollment (cases per 100,000 population), their ranked distribution is consistent with the crude rate. Conclusions: This study observed that the regional distribution of the enrolled cases who reported humidifier disinfectant-related health effects is inconsistent with the regional distribution of the proportional rate of enrollment cases, which may be caused in part by the volume of the inherent population of each region.

• Journal of Environmental Health Sciences
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• v.20 no.3
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• pp.78-84
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• 1994

The effects of heavy metal, Cd on the degradation of the herbicide butachlor (N-Butoxymethyl-2-chlor-2',6'-diethylacetanilide) in soils were examined the laboratory. The degradation of the herbicide in soil was greatly inhibited by the amendment of the heavy metal, Cd. The inhibited rate of Cd concentration was high in the order of 30 ppm>20 ppm> 10 ppm>0 ppm. And tile degradation rate of butachlor was high in order of 80 $\mu$M>40 $\mu$M>20 $\mu$M. The effects of Cd on the degradation of the butachlor in soil varied with concentration of heavy metal and butachlor.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.9
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• pp.853-860
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• 2017

To evaluate the effects of mode II on the crack initiation and propagation stages, the effects in the fatigue threshold region under a mixed-mode I+II loading state was experimentally investigated. In the case of mixed-mode I + II, during the crack initiation stage, as the loading application angle (${\theta}$) increased, cracks occurred in the lower load owing to the effects of mode II, while the crack propagation rate decreased. The effects of mode II were experimentally investigated in the crack propagation stage by means of multilevel loading direction variation. Following mixed-mode I+II ($0^{\circ}{\rightarrow}{\theta}{\rightarrow}60^{\circ}$), as the load application angle increased, the fatigue crack propagation rate decreased, as did the fatigue crack propagation rate, which occurred later. Following mixed-mode I + II in case of(${\theta}{\geq}75^{\circ}$), the fatigue crack propagation rate was found to increase, while the fatigue life decreased.

• Nuclear Engineering and Technology
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• v.53 no.9
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• pp.3003-3011
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• 2021

A FAC (flow-accelerated corrosion) test was performed for a straight pipe composed of the SA335 Gr P22 and SA106 Gr B (SA106-SA335-SA106) types of steel with welds as a function of the flow rate in the range of 7-12 m/s at 150 ℃ and with DO < 5 ppb at pH levels ranging from 7 to 9.5 up to a cumulative test time of 7200 h using the FAC demonstration test facility. Afterward, the experimental pipe was examined destructively to investigate opposite effects as well as entrance effects. In addition, the FAC rate obtained using a pipe specimen with a 50 mm inner diameter was compared with the rate obtained from a rotating cylindrical electrode. The effects of the complicated fluid flows at the elbow and orifice of the pipeline were also evaluated using another test section designed to examine the independent effects of the orifice and the elbow depending on the distance and the combined effects on orifice and elbow. The tests were performed under the following conditions: 130-150 ℃, DO < 5 ppb, pH 7 and a flow rate of 3 m/s. The FAC rate was determined using the thickness change obtained from commercial room-temperature ultrasonic testing (UT).

• Journal of the Korean Society of School Health
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• v.8 no.2
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• pp.305-314
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• 1995

A comparative study on the effects of the water fluoridation program and fluoride mouth rinsing program in the elementary school children. This study was performed to compare the oral health status of permanent teeth for children of the caries prevention effects by using methods of fluoride 309 children for water fluoridated program, 240 for fluoride mouth rinsing program and 248 for control group. The DMFS rate, DMFT index, soft and hard deposite rate were analysed from the oral examination. And 300 questionares from the parents who lived in Cheong ju city were evaluated to see the situations of using the tap water. The results were as follows; 1. Caries experience rate in permanent dentition was the lowest in fluoride mouth rinsing group. 2. It was estimated that soft deposite rate was comparatively low in the fluoride mouth rinsing group but calculus deposite rate was no significant difference in each other groups. 3. The 72.0 percentage of parents who lived in non fluoridated water area were misunderstood that they lived in water fluoridated area. 4. The 66.8 percentage of residents used the piped water as drinking water. 5. It was recommended that fluoride mouth rinsing program was suggested in rural area, on the other hands, toothbrusing program in urban area with water fluoridation to prevent the dental caries for school children.

• Preventive Nutrition and Food Science
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• v.3 no.3
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• pp.287-291
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• 1998

Brining property and antimutagenic effects of organically cultivaged Chinese cabbage kimchi (OC kimchi) and common Chinese cabbage imchi (CC kimchi) were studied. The salt absorption rate of leaves was faster than that of stems of the Chinese cabbages. Due to the large portion of leaf in organic Chinese cabbage, organic Chinese cabbage(OC) was much faster in terms of salt absorption rate than common Chinese cabbage(CC). The antimutagenic effects of methanol extracts of CC kimchi and OC kimchi were studied against aflatoxin B1(AFB1) using Ames test on Samonella typhimurium TA 100 and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) using SOS chromotest. Methanol extract from 6 -day fermented OC kimchi at 15 $^{\circ}C$ showed 80% inhibition rate against the indirect mutage, aflatoxin B1 induced mutagenicit where as that from 6-day fermented CC kimchi at 15 $^{\circ}C$ showed 54% inhibition rate in the Ames test. Methanol extracts from 6-day fermented CC kimchi and OC kimchi showed 27 % and 58 % inhibition rate against direct mutagen , N-methyl-N'-nitro-N-nitrosoguanidine induced mutagenicity, respectively in SOS chormotest, thus OC kimchi exhibited higher antimutagenic activity than kimchi.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.11
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• pp.1486-1496
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• 2000

The initial flame kernel development and flame propagation in a constant volume combustion chamber is analyzed by the heat release rate and the mass fraction burnt. The combustion pressure is measured with a piezoelectric type pressure sensor. In order to evaluate the effects of ignition system and ignition energy on the flame propagation, four different ignition systems are designed and tested, and the ignition energy is varied by the dwell time. Several different spark plugs are also tested and examined to analysis the effects of electrodes on flame kernel development. The results show that the when the dwell time is increased, and when the spark plug gap is extended, heat release rate and the mass burnt fraction are increased. The materials and shapes of electrodes affect the flame development, because they change the energy transfer efficiency from electrical energy to chemical energy. The diameter of electrodes influences not only the heat release rate but also the mass burnt fraction as well.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.8
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• pp.139-149
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• 2001

The effects of the cutting conditions on the surface roughness of workpiece in turning were studied in this paper. The workpieces made of carbon steel SM20C and SM45C were tamed without the support of the tailstock center. Cutting conditions were changed in three or flour steps in each parameter and cutting fluid was used. The surface roughness results of tests were measured and the effects of the cutting conditions were analyzed by the method of analysis of variance. The summary of the experimental research is as follows. The main parameters were cutting speed, fred-rate, depth of cut, and the interactions between speed and fled-rate, speed and depth of cut, and fred and depth of cut. As cutting speed increased, surface roughness showed lower value. The surface roughnesses of feed-rate 0.102 mm/rev and 0.147 mm/rev were better than those of feed-rate 0.05 mm/rev and 0.2 mm/rev.

• The Korean Journal of Nuclear Medicine
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• v.14 no.2
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• pp.35-40
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• 1980

In order to compare the therapeutic effect as well as side effects between antithyroid therapy and radioiodine therapy in hyperthyroidism, the author evaluated 111 cases of hyperthyroidism which were composed of 57 patients with antithyroid treatment, 23 patients with combined treatment comprising of antithyroid and radioactive iodine ($^{131}I$) and 31 patients with treatment of $^{131}I$ alone. The $^{131}I$ treatment was limited to older age, above 20 years of age, and not employed in patients with pregnancy and lactation. The patients treated with antithyroid belonged to relatively younger age, and also milder in symptoms and thyroid function tests. The remission rate of antithyroid therapy group was 97.8% within 16 months. Among them the early remission rate occured within 4 months was found to be 21.7%. The combined therapy group, having prescribed more severe cases, showed the remission rate to be 75% within 16 months. The remission rate of $^{131}I$ therapy group revealed 90.9% within 16 months. Among them the early remission rate taking place within 4 months disclosed 16.7%. The side effects of antithyroid drug, propylthiouracil, were noted as follows: itching (2.7%) skin rashes (1.3%), and adverse enlargement of goiter (10.7%). The side effects $^{131}I$ therapy were transient hypothyroidism(3.9%) permanent hypothyroidism (7.8%) and itching (2.0%).

• The Journal of Industrial Distribution & Business
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• v.8 no.2
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• pp.5-10
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• 2017

Purpose - The purpose of this paper was to analyze the Chinese government's announcement of the RMB's appreciation on July 1, 2010, and its aim was to ascertain whether the appreciation has affected Chinese export prices by empirically measuring the degree of the exchange rate pass-tough on those prices. Research design, data, and methodology - Using 73 HS trade categories with cross-industry and time-series data, the panel estimation of a fixed-effects model has been applied to measure the degree and stability of any exchange rate pass-through effects. The estimation results show that the export prices of most trade categories were affected by the exchange rate changes. The pass-through effect was generally small, at about -0.485, and statistically significant in most export prices. Results - The empirical results indicate that China would lose its advantage and competitiveness in export if the RMB were appreciated continuously and rapidly because its export goods would no longer operate under strong monopolistic competition. Conclusions - The implications for China's exchange rate policy suggest that it would be better for the RMB to appreciate slowly and gradually rather than radically. It is clear that it would be allow the capital free flow in Chinese overall economic interest to reduce the continuous appreciation pressure on the currency and pave the way for improvements in export distribution competitiveness.