• Journal of Digital Convergence
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• v.10 no.8
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• pp.201-210
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• 2012

Because sensing odor varies depending on each person, even if the odor is released in line with the legal emission permission concentration levels, it can still become a social issue if a civil complaint is made. The purpose of this research is to study the possibility of putting Mn-Cu metallic oxide catalysts into practical use to economically eliminate acetaldehyde which produces a odor in the industrial process. An optimal operating parameter to eliminate acetaldehyde was deduced through a performance evaluation in the research laboratory and the performance was verified by applying the parameter into an actual facility as an on-the-site experiment through a Scale-up of pilot size. The operating temperature of the metallic oxide catalysts researched so far was at the minimum close to $220^{\circ}C$, and the $220^{\circ}C$ elimination efficiency was 50% or below. However, having experimented by using a Mn-Cu metallic oxide catalyst in this research, optimum elimination efficiency showed when space velocity (GHSV) was equal to or below 6,000 $hr^{-1}$. The average elimination efficiency was 61.2% when the catalyst controlling temperature was $120^{\circ}C$, 93.3% when the catalyst controlling temperature was $160^{\circ}C$, and 94.9% when catalyst controlling temperature was $180^{\circ}C$, thereby reflecting high elimination efficiency. The specific surface area of the catalyst was $200m^2/g$ before use, however, was reduced to $47.162m^2/g$ after 24 months and therefore showed that despite the decrease in specific surface area as time passed, there was no significant influence on the performance. Having operated Mn-Cu metallic oxide catalyst systems for at least two years on a site where there was no inflow of toxins like sulfur compounds and acidic gases, we were able to confirm that elimination efficiency of at least 90% was maintained.

• Clean Technology
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• v.28 no.2
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• pp.131-137
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• 2022

The semiconductor process currently emits various by-products and unused gases. Emissions containing pollutants are generally classified into categories such as organic, acid, alkali, thermal, and cabinet exhaust. They are discharged after treatment in an atmospheric prevention facility suitable for each exhaust type. The main components of organic exhaust are volatile organic compounds (VOC), which is a generic term for oxygen-containing hydrocarbons, sulfur-containing hydrocarbons, and volatile hydrocarbons, while the main components of alkali exhaust include ammonia and tetramethylammonium hydroxide. The purpose of this study was to determine the combustion characteristics and analyze the NO_X reduction rate by maintaining a direct combustion and temperature to process organic and alkaline exhaust gases simultaneously. Acetone, isopropyl alcohol (IPA), and propylene glycol methyl ether acetate (PGMEA) were used as VOCs and ammonia was used as an alkali exhaust material. Independent and VOC-ammonia mixture combustion tests were conducted for each material. The combustion tests for the VOCs confirmed that complete combustion occurred at an equivalence ratio of 1.4. In the ammonia combustion test, the NO_X concentration decreased at a lower equivalence ratio. In the co-combustion of VOC and ammonia, NO was dominant in the NO_X emission while NO₂ was detected at approximately 10 ppm. Overall, the concentration of nitrogen oxide decreased due to the activation of the oxidation reaction as the reaction temperature increased. On the other hand, the concentration of carbon dioxide increased. Flameless combustion with an electric heat source achieved successful combustion of VOC and ammonia. This technology is expected to have advantages in cost and compactness compared to existing organic and alkaline treatment systems applied separately.

• Journal of dental hygiene science
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• v.11 no.3
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• pp.213-220
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• 2011

To examine the relationship between occurrence of oral malodor and smoking, drinking, oral health behavior characteristics. A total of 144 adults were measuring the malodor by use of Oral Chroma volatile sulfur compounds. Data were analyzed with t-test, one-way of variance and multiple regression analysis using SPSS 12.0. hydrogen sulfide($H_2S$) was indicated to be so higher concentration in the group of carrying out scaling sometimes than the regularly group(p<0.01). methyl mercaptan($CH_3SH$) was indicated to be higher concentration in previous smoker than non-smoker and smoker(p<0.05), smoking for over 20 years was higher than the under 20 years group(p<0.05). The group of drinking over 5 times a week was indicated to have higher concentration than the under once-twice a week group(p<0.01). The group of not toothbrushing before going to sleep had higher concentration than the group of toothbrushing before going to sleep(p<0.05). The group of scaling sometimes was indicated to have higher concentration than the group of scaling regularly(p<0.05). dimethyl sulfide($(CH_3)_2S$) was indicated to be higher concentration in the group with over 2 bottles of Soju than in the group with under 1 bottles of Soju(p<0.01). The regular scaling will need to be carried out in the preventive dimension for managing oral malodor. The guidance on non-smoking and moderation in drink will need to be surely included.

• Journal of Conservation Science
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• v.31 no.3
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• pp.243-254
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• 2015

In this study, the stability of the adhesive was determined through the Oddy Test that is Verification Test for potential damage by various materials. And to find the factor causing the corrosion of the metal samples, the adhesives and coatings those are usually used in the metal preservation process were selected and treated on the samples. Six kinds of adhesives and four kinds of metal specimens Fe, Pb, Cu, Ag were used. As results, the weight change showed high increasement in the rate of weight change 29.87% of Fe sample. The chromaticity measurement showed the high change value of the Cellulose-based adhesive. In case of the VOCs test from adhesive by using GC-MS, Acetic acid was detected from all six kinds of the adhesives. Compared to cellulose-based adhesives and the other adhesives, the amount of VOCs per 1mg concentration is higher than 900 times and was detected small amount of Formic acid. This is assumed to be facilitated by acid impurities and the light. This reaction was considered as the result of reducing a large amount of molecular and of generating a large amount of Nox. And thus the reacted sulfur changes was considered as the factor for causing corrosion.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.40 no.2
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• pp.187-193
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• 2014

Dental caries are one of the most common oral diseases and Streptococcus mutans (S. mutans) plays an important role in the initiation and progression of dental caries. Oral malodor is primarily the result of microbial metabolism such as Porphyromonas gingivalis (P. gingivalis) that produce volatile sulfur compounds (VSCs), causing oral malodor. Prevotella intermedia (P. intermedia) is known as typical periodontopathic bacteria, and periodontal disease is chronic inflammatory disease that leads to damage of gingival connective tissue and alveolar bone, eventually loss of teeth. In this study, we investigated antimicrobial effect of mouthwash containing cetylpyridinium chloride (CPC), sodium fluoride (NaF), green tea water extract and pine needles water extract against cariogenic and periodontopathic bacteria sucn as S. mutans, P. gingivalis and P. intermedia. As a result, the reduction ratios of S. mutans and P. gingivalis were 4.00 Log and 4.68 Log reduction for 30 s, and P. intermedia were 2.40 Log reduction for 30 s and 2.70 Log reduction for 60 s. Dentocult SM Strip mutans (SM Strip) provides easy detection of visual data showing a significant inhibition on S. mutans. In conclusion, we expected that mouthwash containing CPC, NaF, green tea water extract and pine needles water extract could help preventing the dental disease like dental caries and oral malodor.

• Journal of Korea Port Economic Association
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• v.36 no.3
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• pp.21-38
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• 2020

Currently, in-port emissions are a serious problem in port cities. However, emissions, especially non-greenhouse gases, from the operation of cargo handling equipment (CHE) have received significant attention from scientific circles. This study estimates the amount of emissions from on-land port diesel-powered CHE in the Port of Incheon. With real-time activity data provided by handling equipment operating companies, this research applies an activity-based approach to capture an up-to-date and reliable diesel-powered CHE emissions inventory during 2017. As a result, 105.6 tons of carbon monoxide (CO), 243.2 tons of nitrogen oxide (NOx), 0.005 tons of sulfur oxide (Sox), 22.8 tons of particulate matter (PM), 26.0 tons of volatile organic compounds (VOCs), and 0.2 tons of ammonia (NH3) were released from the landside CHE operation. CO and NOx emissions are the two primary air pollutants from the CHE operation in the Port of Incheon, contributing 87.71% of the total amount of emissions. Cranes, forklifts, tractors, and loaders are the four major sources of pollution in the Port of Incheon, contributing 84.79% of the total in-port CHE emissions. Backward diesel-powered machines equipped in these CHE are identified as a key cause of pollution. Therefore, this estimation emphasizes the significant contribution of diesel CHE to port air pollution and suggests the following green policies should be applied: (1) replacement of old diesel powered CHE by new liquefied natural gas and electric equipment; (2) the use of NOx reduction after-treatment technologies, such as selective catalytic reduction in local ports. In addition, a systematic official national emission inventory preparation method and consecutive annual in-port CHE emission inventories are recommended to compare and evaluate the effectiveness of green policies conducted in the future.

• The Journal of Internal Korean Medicine
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• v.28 no.1
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• pp.97-105
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• 2007

Objectives : This study investigated the correlation between dry mouth and comprehensive diagnosis of Qi xu and Qi yu in patients with halitosis. Methods : We surveyed 124 halitosis patients by reviewing the questionnaires from the Halitosis Clinic in the Hospital of Oriental Medicine, Kyunghee University from January 2004 to March 2006. The halitosis questionnaires contained self-awareness of halitosis, self-assessed severity of halitosis, dry mouth and taste abnormality. Among comprehensive diagnosis of Qui Xue Shui, Qi xu and Qi yu parts were investigated by questionnaire and physical examination, and each Qi xu and Qi yu part scores were summed. Winkel tongue coating index was estimated by investigator, the level of volatile sulfur compounds were measured by halimeter, and salivary function was assessed by salivary scan test. All patients were divided into two groups based on salivary scan test (salivary function normal and decreased). Results : Qi xu score of halitosis patients with decreased salivary function was higher than normal halitosis patients. There was highly significant correlation between Qi yu score and dry mouth, and another significant correlation between self-assessed halitosis severity and dry mouth was noted. Conclusions : The results of this study suggest that Qi yu condition influences dry mouth in halitosis patients, and halitosis is affected by dry mouth. Therefore. we assume that treating Qi yu condition can be a potentially effective way of treating dry mouth and halitosis.

• The Journal of Korean Medicine
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• v.31 no.1
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• pp.23-29
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• 2010

Objective: The aim of this prospective, case-controlled study was to assess the difference of the amount of tongue coating between halitosis and non-halitosis patients using a digital tongue diagnosis system (DTDS). Methods: Sixty-five patients complaining of oral malodor were recruited for the study. The level of volatile sulfur compounds (VSC) in the oral cavity of the patients was measured by a portable gas chromatography. All patients were then divided into two groups, the halitosis group ($H_2S{\geq}1.5ng$/10ml, or $CH_3SH{\geq}0.5ng$/10ml) and the non-halitosis group ($H_2S$<1.5ng/10ml and $CH_3SH$<0.5ng/10ml), according to the VSC level criteria published by Tonzetich. Tongue images of the two groups were acquired and analyzed by DTDS, followed by the analysis of the tongue coating scores. Results: The tongue coating scores of the halitosis group were significantly higher than of the non-halitosis group (P=0.033). Furthermore, the difference of the posterior tongue coating between the two groups was more significant (P=0.000). Conclusions: Halitosis patients were shown to have a thicker tongue coating than those in the non-halitosis group. Moreover, the posterior dorsum of the tongue should be observed more cautiously when dealing with halitosis patients. Also, the progress and state of the patient's symptom of halitosis as diagnosed objectively by the portable gas chromatography could also possibly be analyzed instead by the DTDS tongue coating score.

• Journal of Life Science
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• v.23 no.3
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• pp.443-447
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• 2013

This study was conducted to investigate the antimicrobial and anti-oral malodor effect of Schizandra chinensis extracts against oral pathogens. S. chinensis methanol (MeOH) extract showed better antimicrobial activities against oral pathogens than the S. chinensis hot water extract did. In particular, ethylacetate (EA) fraction of S. chinensis MeOH extract had the greatest effects against Streptococcus mutans, S. sanguinis, S. salivaris subsp. thermophols and Porphyromons gingivalis. The anti-malodor effect of S. chinensis against the generation of volatile sulfur compounds (VSC), such as hydrogen sulfide, methyl mercaptan, and dimethyl sulfide, was estimated using oral chroma in a practical study. The results showed that 2% MeOH extract of S. chinensis against the production of hydrogen sulfide, methyl mercaptan, and dimethyl sulfide had inhibitions of 91.15, 78.72 and 71.58%, respectively. These results showed that Schizandra chinensis extract had antimicrobial activity against several oral pathogens and exhibited significant effects on the inhibition of VSCs. Thus, Schizandra chinensis extract could be an alternative to available synthetic chemicals and oral hygiene products.

• Journal of Korean society of Dental Hygiene
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• v.23 no.2
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• pp.91-103
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• 2023

Objectives: This case study was conducted to assess changes in the concentration of volatile sulfur compounds (VSCs) of older adults following home oral health care interventions based on community care. Methods: The participants were three elderly people with the halitosis. An oral health intervention programs including oral massage, oral hygiene care, and oral muscle training strenghtening were conducted for 12 weeks. Halitosis was measured using an oral malodor-checking device. Results: The program showed positive effects on changes in halitosis. The concentration of VSCs of the first case decreased rapidly from 44.5 Refres Oral Volume (ROV) on pre-test to 15.5 ROV on the first post-test. In the second case, the score decreased from 14.5 ROV on pre-test to 12 ROV on 2nd post-test. In the third case, the score decreased slightly from 6.5 ROV on pre-test to 6 ROV on the first post-test. Conclusions: Oral health care interventions contributed to decreasing the concentration of VSCs and improving the quality of life of older adults. The active promotion and customization of these programs are required.