• 제목/요약/키워드: Harmful Effect

검색결과 907건 처리시간 0.03초

유해물질 및 공업용 분진 제거를 위한 산업용 후드 개선에 관한 연구 (A Study on Improvement of Industrial Hood in Ventilation System for Elimination of Harmful Material and Dust)

  • 김영선;오율권
    • 설비공학논문집
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    • 제20권4호
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    • pp.238-244
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    • 2008
  • This study investigates on the improvement of inhalation effect of hood which attached new device named as "gas-guide-device" in local exhaust ventilation system for the effective elimination of harmful material and dust in manufacturing factory. The gas-guide-device having a diamond shape is composed of width (b) and two sides of a device (X, Y) and its size is selected the industrial hood under application in manufacturing factory after due consideration. In order to investigate the effect of gas-guide-device, numerical and experimental study is performed that the flow velocity is calculated and is measured by a commercial program "COMSOL $Multiphysics^{TM}$" and a hot wire type of anemometer, respectively. The numerical and experimental results are revealed is a similar pattern and flow velocity has improved to hood attached gas-guide-device. Also, the numerical method and result is also verified the dependance. Moreover, the optimum shape and size of gas-guide-device is revealed that the width (b) and the ratio of two sides of gas-guide-device (X, Y) has 125mm and 4 to 6.

숲길 조성공사 작업자의 작업자세 분석에 관한 연구 (Analysis of working posture of forest trail construction)

  • 이명교;박범진;이준우;최성민
    • 농업과학연구
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    • 제42권2호
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    • pp.117-124
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    • 2015
  • In forest work, working conditions are very hard to improve. The good posture is believed to bring about direct improvements such as accident prevention. Therefore, this research carried on analysis of working posture in forest work (construct in stepping-stone) using OWAS analysis system. According to the analytical results provided by OWAS, the ratio of category III (Work posture has a distinctly harmful effect on the musculoskeletal system) has shawn that worker 2 was 32.2%, worker 1 was 25.2% and worker 3 was 15.5%. Furthermore, the ratio of category IV (Work posture with an extremely harmful effect on the musculoskeletal system) has shown that worker 2 was 9.8%, worker 3 was 1.4% and worker 1 was 1.2%. According to the OWAS method, percentage of OWAS action categories III and IV in the worker 2 was higher than another workers.

생균제와 제올라이트를 혼합한 축분첨가제가 돈분 슬러리에서 발생하는 유해 가스 발생량에 미치는 영향 (Effect of Manure Additives Mixed with Probiotics and Zeolite on Harmful Gas Production Released From Pig Slurry)

  • 장우환;최인학
    • 한국환경과학회지
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    • 제31권1호
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    • pp.99-102
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    • 2022
  • The aim of this study was to investigate the effect of manure additives mixed with probiotics and zeolite on harmful gas production generated by pig slurry. A total of 180 crossbred pigs ([Yorkshire × Land race] × Duroc, live weight 70±3.21 kg) were allotted to a completely randomized design with 3 treatments and 3 replications (20 heads per replicate). The treatments consisted of 0% (control), 0.05% (T1), or 1% (T2) of manure additives mixed with probiotics and zeolite. Manure additives were added weekly to pig slurry pits (2 m × 4.5 m × 1.2 m) on a volumetric basis. For ammonia measured at both 10 cm and 90 cm above the pig slurry pit, a statistical significance (p<0.05) was found in probiotics and zeolite-treated manure additives at weeks 1 - 3, except for week 0. In addition, hydrogen sulfide levels measured at 10 cm above the pig slurry pit were not affected by the manure additive at weeks 0 and 1, but showed a significant statistical difference at weeks 2 and 3 (p<0.05). Therefore, supplementing pig slurry with 0.05% and 0.1% manure additives mixed with probiotics and zeolite was found to be effective in reducing environmental pollution in pig facilities.

Characteristics of Bovine Teeth Whitening in Accordance with Gas Environments of Atmospheric Pressure Nonthermal Plasma Jet

  • Sim, Geon Bo;Kim, Yong Hee;Kwon, Jae Sung;Park, Daehoon;Hong, Seok Jun;Kim, Young Seok;Lee, Jae Lyun;Lee, Gwang Jin;Lim, Hwan Uk;Kim, Kyung Nam;Jung, Gye Dong;Choi, Eun Ha
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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    • pp.250.2-250.2
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    • 2014
  • Currently, teeth whitening method which is applicable to dental surgery is that physician expertises give medical treatment to teeth directly dealed with a high concentration of hydrogen peroxide and carbamide peroxide. If hydrogen peroxide concentration is too high for treatment of maximized teeth whitening effect [1], it is harmful to the human body [2]. To the maximum effective and no harmful teeth whitening effect in a short period of time at home, we have observed the whitening effect using carbamide peroxide (15%) and a low-temperature atmospheric pressure plasma jet which is regulated by the Food and Drug Administration. The gas supplied conditions of the non-thermal atmospheric pressure plasma jet was with the humidified (0.6%) gas in nitrogen or air at gas flow rate of 1000 sccm. Also, the measurement of chemical species from the jet was carried out using the optical emission spectroscopy (OES), the evidence of increased reactive oxygen species compared to non-humidified plasma jet. We have found that the whitening effect of the plasma is very excellent through this experiment, when bovine teeth are treated in carbamide peroxide (15%) and water vapor (0.2 to 1%). The brightness of whitening teeth was increased up to 2 times longer in the CIE chromaticity coordinates. The colorimetric spectrometer (CM-3500d) can measure color degree of whitening effect.

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정신지체장애인의 구강보건교육 효과에 관한 연구 (A Study on the Effect of Oral Health Education on the Mentally Retarded Children)

  • 김영숙
    • 한국치위생학회지
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    • 제1권1호
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    • pp.19-37
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    • 2001
  • The purpose of this study was to develop effective oral health education programs for mentally retarded children and promote their oral health, by offering oral health education for 45 mentally retarded children between age 6 to 20, tracking the change of their knowledge depending on the frequency of education, and examining the educational effect before and after oral health education. The children with mental retardation attended a special school for idiots in Gweonseon-gu, Suwon, Kyonggi Province, being able to take training(IQ 25-49). The education program was designed to be suitable for their cognitive power after consultation with a special school teacher. A teacher provided the same education seven times, once a week, and an interview was held with each of them to assess their correct answer rate. The findings of this study were as below: 1. The repeated oral health education served to have the children with mental retardation acquire better knowledge about harmful food for the teeth, what had to be done after eating cookies or candies between meals, the right time for toothbrushing, the concept of dental caries, and how to cope with dental caries(p<0.01). But after that education was offered four times, the frequency of that education made no difference. 2. The repeated oral health education increased, their knowledge on the role of the teeth and the right choice of toothbrush(p<0.01), yet there was no significant difference in their knowledge about oral health behavior, because they had already been familiar with that. 3. As a result of investigating the change of their oral health know-ledge before and after oral health education according to the type of handicap, the type of handicap made no significant difference to the change of their oral health knowledge. 4. The oral health education for the children with menial retardation had a significantly different effect on their knowledge about harmful food for the teeth, what had to be done after eating between meals, the right time for toothbrushing, the role of the teeth. the right choice and use of toothbrush, how to do toothbrushing, and fluorine(p<0.01).

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항균성 펩타이드인 mastoparan B의 살조효과 (The Algicidal Effect of Antimicrobial Peptide, Mastoparan B)

  • 서정길;김찬희;배윤정;문호성;김근용;박희연;윤호동;김창훈;변대석;홍용기;박남규
    • 한국어병학회지
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    • 제16권3호
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    • pp.193-201
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    • 2003
  • Mastoparan B (MPB)는 벌독으로부터 정제된 양친매성 $\alpha$-helical 구조를 취하면서 14개의 아미노산 잔기로 구성된 염기성 항균성 펩타이드로서 여러가지 생물막과 작용한다. 본 연구에서는 우리 나라 연안의 적조 (HABs, harmful algal blooms)를 일으키는 4종의 적조생물 (Alexandrium tamarense, Chattonella marina, Cochlodinium polykrikoides 및 Gymnodinium catenatum)에 대한 MPB의 살조효과를 조사하였다. MPB의 4종의 적조생물에 대한 살조효과는 31.3 $\mu{g}$/mL부터 500 $\mu{g}$/mL에서 세포의 lysis 또는 ecdysis와 같은 형태로 현미경으로 관찰할 수 있었다. 또한 MPB는 C. marina 및 C. polykrikorides에 대해서 A. tamarense와 G. catenatum보다 더욱 강한 살조효과를 나타내었다. 이러한 MPB의 HABs에 대한 살조효과연구는 새로운 살조물질을 개발하기 위한 자료가 될 것으로 생각된다.

항균성 펩타이드인 Apidaecin Ib의 살조효과 (The Algicidal Effect of Antimicrobial Peptide, Apidaecin Ib)

  • 김찬희;김은정;고혜진;김인혜;이병우;박남규
    • 한국어병학회지
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    • 제17권2호
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    • pp.123-130
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    • 2004
  • 꿀벌 (Apis mellifera)의 lymph 액으로부터 정제된 항균성 펩타이드인, Apidaecin Ⅰb는 18개의 아미노산 잔기로 구성된 염기성 non-helical 펩타이드이다. 본 연구에서는 우리나라 연안의 적조 (HABs, harmful algal blooms)를 일으키는 4종의 적조생물 (Alexandrium tamarense, Chattonella marina, Cochlodinium polykrikoides 및 Gymnodinium catenatum)에 대한 Apidaecin Ⅰb의 살조효과를 조사하였다. Apidaecin Ⅰb의 4종의 적조생물에 대한 살조효과는 12.5$\mu{g}/mL$부터 50$\mu{g}/mL$에서 세포의 lysis 또는 ecdysis와 같은 형태로 현미경으로 관찰할 수 있었다. 또한 Apidaecin Ⅰb는 C. marina에 대해서 A. tamarense, C. polykrikorides 및 G. catenatum보다 더욱 강한 살조효과를 나타내었다. 이러한 HABs에 대한 Apidaecin Ⅰb의 살조효과 연구는 새로운 살조물질을 개발하기 위한 자료가 될 것으로 생각된다.

근채류의 기호도와 장내세균의 유해효소 억제효과 (The Preference and Inhibitory Effect of Root Vegetables on β-Glucuronidase and Tryptophanase of Human Intestinal Bacteria)

  • 한명주;김나영
    • 한국식품조리과학회지
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    • 제15권6호
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    • pp.555-564
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    • 1999
  • 식이섬유를 함유한 근채류의 기호도를 조사하고 장내유산균 증식효과와 장내유해균이 생산하는 ${\beta}$-glucuronidase와 tryptophanase 저해효과를 측정한 결과는 다음과 같다. 1. 조사대상자가 가장 선호하는 근채류는 고구마(4.05)였으며 남자의 선호도는 감자(3.88), 고구마(3.68), 더덕(3.77), 무(3.59), 양파(3.56)의 순으로 나타났으며 여자는 고구마(4.17), 감자(4.03), 양파(3.76), 무(3.61), 더덕(3.55)의 순으로 나타났다. 2. 여자가 남자보다 '근채류가 건강에 좋다'고 인식하고 있었으며 건강에 좋다고 생각하는 근채류는 남자의 경우 마늘 26.4%, 당근 16.7%, 감자 15.3%, 더덕 12.5%의 순으로 나타났고 여자의 경우 마늘 26.7%, 더덕 17.3%, 감자 13.9%, 당근 10.4%의 순으로 나타났다. 3. 근채류 추출물 0.5%를 첨가한 배지에서 장내유익균인 B. breve K-110의 증식효과는 감자(139%), 더덕(145%), 마(164%), 토란(144%), 연근(147%)에서 높았다. 장내유익균(B. breve K-110)과 유해균(E. coli HGU-3와 Bacteroides JY-6)을 혼합배양시 근채류 추출물 0.5% 첨가한 배지에서 장내유해균이 생산하는 유해효소인 ${\beta}$-glucuronidase와 tryptophanase 활성저해 효과는 감자, 더덕, 마, 토란에서 높게 나타났다. 감자, 더덕, 마, 토란추출물을 0.5% 첨가한 배지에 사람의 장내세균총을 배양하였을 때 이들 유해효소의 활성은 50%이상의 억제효과가 나타났다. 4. Sephadex G-100 column chromatography에 의하여 분리한 감자, 마, 더덕, 토란추출물의 고분자 분획에서 장내유익균인 B. breve K-110의 증식효과와 ${\beta}$-glucuronidase와 tryptophanase 활성저해 효과가 높게 나타났다. 5. 분리한 고분자 분획의 ninhydrin 발색반응은 감자, 마, 더덕, 토란에서 음성을 나타내어 아미노산이 아닌 것을 확인하였고 요오드반응은 마, 더덕, 토란에서 음성을 나타내었고 감자에서는 양성을 나타내었다. 이상과 같은 결과에 의하면 근채류중 감자, 마, 더덕, 토란이 유산균을 효과적으로 증식시켜 장내 pH를 저하시킴에 의해 ${\beta}$-glucuronidase, tryptophanase와 같은 장내의 유해효소를 억제할 것이라고 기대되어진다. 그러므로 이들 근채류는 장내의 유해효소에 의해 발생하는 대장암등의 질병예방과 장내균총의 불균형에 의해 야기될 수 있는 설사와 변비같은 질병의 예방에도 효과를 나타낼 것으로 생각된다.

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Effect of alloying Copper on the Corrosion Resistance of Stainless Steels in Chloride Media

  • Ujiro, T.;Satoh, S.;Staehle, R.W.;Smyrl, W.H.
    • Corrosion Science and Technology
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    • 제2권3호
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    • pp.127-134
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    • 2003
  • In order to explain the effect of alloying Cu on the corrosion resistance of stainless steels in chloride media for both ferritic and austenitic stainless steels, the corrosion behavior of Cu-bearing stainless steels was investigated. Alloying Cu showed beneficial effect in an active potential range and harmful effect in a noble potential range. The beneficial effect of alloying Cu was explained by the stability of deposited Cu on an anodic surface. Difference in the effect of alloying Cu between the ferritic and austenitic steels was ascribed by the differences in their corrosion potentials and the morphology of the deposited Cu.

Protective effect of metabolized Chungpesagan-tang on Hypoxia/Reperfusion induced-PC12 cell damage

  • Lee, Eun-Su;Park, Jung-Ran;Sohn, Nak-Won;Soh, Yun-Jo
    • 대한약학회:학술대회논문집
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    • 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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    • pp.94.1-94.1
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    • 2003
  • This research was performed to investigate the protective effect of Chungpesagan-tang (CPS) against ischemic damage in PC12 cells. To elucidate the mechanism of the protective effect of CPS on ischemic insult, cell viability and changes in activities of Superoxide dismutase, Glutathione Peroxidase, Catalase, Caspase 3 and the production of Malondialdehyde were observed after treating PC12 cells with CPS which was metabolized by rat liver homogenate. Pretreatment of CPS with liver homogenate increased its protective effect against ischemic insult by reducing the harmful effect of CPS itself. (omitted)

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