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검색결과 16,776건 처리시간 0.044초

Estimation of the relationship between below-ground root and above-ground canopy development by measuring dynamic change of soil ammonium-N concentration in rice

  • Fushimi, Erina;Yoshida, Hiroe;Tokida, Takeshi;Nakagawa, Hiroshi
    • 한국작물학회:학술대회논문집
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    • 한국작물학회 2017년도 9th Asian Crop Science Association conference
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    • pp.183-183
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    • 2017
  • In the early part of rice growth, root volume primarily limits the amount of plant-accessible nitrogen (N). Therefore, knowledge of the root development is important for modeling N uptake of rice. The timing when the volume of rhizosphere cover the whole soil is also important to carry out timely top dressing. However, information about initial root expansion and associated N uptake is limited due to intrinsic technical difficulties in assessing below-ground processes. Some studies, however, showed a close relationship between below-ground root and above-ground leaf development, suggesting a possibility that above-ground attributes could serve as surrogates for the root processes. In this study, we investigated the relationship between below-ground and above-ground development of rice. Field experiments were conducted where we cultivated Koshihikari (a leading cultivar in Japan) for four different cropping schedules in 2012. In 2016, Gimbozu (HEG4) and three flowering time mutant lines of Gimbozu (X61 (se13), HS276 (ef7), DMG9 (se13, ef7)) were examined for a single season. Experiments were performed with three replications in a completely randomized design. We monitored ammonium-N concentration ([NH4+-N]) in soil solution by repeatedly taking samples from a porous tubing (10-cm long) vertically inserted at the most distant point from surrounding rice hills. Samples were taken in triplicate (= triplicate tubes) and every three days from transplanting in each experimental unit. For above-ground attributes, leaf area index (LAI) was measured in 2012, whereas soil coverage ratio was estimated by image processing in 2016. Results showed that [NH4+-N] increased gradually after transplanting and then rapidly decreased from a certain day. This distinct drop in [NH4+-N] informed us the timing at which the rice root system reached the point of porous tubing and thus essentially covered the whole soil volume. The LAI at the dropping point was about 0.43 regardless of the cropping schedules in 2012 experiment. In 2016, the coverage ratio at the N dropping point was within the range of 0.12 to 0.19 for four genotypes having different growth durations. In addition, the coverage ratios at seven weeks after the transplanting showed a good correspondence to LAI across the four genotypes. We therefore conclude that both LAI and coverage ratio may serve as robust indicators for root development and might be useful to estimate the timing when the root system fully cover the soil volume. Results obtained here will also contribute to develop models that can predict not only above-ground canopy development but also associated below-ground processes.

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CO2 용접에서 용접변수의 변화에 따른 용접흄 제어방법에 관한 연구 (A Study on Control of Fume for Various Parameters in CO2 Welding)

  • 오광중;김현수;손병현;지해성
    • 한국산업보건학회지
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    • 제8권1호
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    • pp.76-87
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    • 1998
  • The concentration of welding fume was measured by 221 welders themselves in chassis frame workplace of the manufactory from February, 1, 1996 to May, 31, 1997. Welding parameters were the welding current and the distance between helmet and arc. Those two optimum conditions were proposed by excess probability analysis using logistic regression, so the best position in the workplace was proposed considering two factors to control the welding fume. The results are as followings; 1) The excess proability of welding fume TLV was over 99% in above 260 Amperes of welding current and also in below 30cm of distanced between helmet and arc. 2) The equation from logistic regression analysis using SPSS/PC+5.02 had the welding current as a independent variable and the excess of welding fume TLV as a dependent variable (p<0.05). Logit(welding fume TLV) = 0.1296 ${\times}$ wlding currnet - 28.8750 3) The equation from logistic regression analysis using SPSS/PC+5.02 had the distance between helmet and arc as a independent variable and the excess of welding fume threshold limit value a, a dependent variable (p<0.05). Logit (welding fume TLV) = -0.6809 ${\times}$ distance between helmet and arc +25.1665 4) Considering both cases or 2) and 3). the result equation is following. (p<0.05). Logit (welding fume TLV) = 0.1346 ${\times}$ welding current -0.3859 ${\times}$ distance between helmet and arc -15.7382 5) The excess probability of welding fume threshold limit value was 100% in above 240 Ampere of welding current. Thus, below 220 Ampere can be suggested to reduce the 40% number of welders who have a excess welding fume threshold limit value. 6) The excess probability of welding fume TLV was 100% in below 34cm of distance between helmet and arc. Thus, over 38cm can be suggested to reduce the 33% number of welders who have a excess welding fume TLV. 7) Considering both 5) and 6) cases, first of all, the best welding current can be 200 Ampere to have a below 15% of welding fume excess probability for the welders who works in distance of 34-37cm. Secondly, to have a below 30% excess probability of welding fume TLV, the working distance must be over 38cm in 220 Ampere and 32cm in 200 Ampere. 8) To reduce the average exposure concentration of welding fume ($8.21{\pm}5.83mg/m^3$), the movable local exhaust system equipped with flexible hoods can be used.

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독일가문비나무(Picea abies [L.] Karst)의 지상부(地上部)와 지하부(地下部) 생체량(生體量)에 관(關)한 연구(硏究) : 흉고직경(胸高直徑)에 의한 뿌리생체량(生體量) 추정(推定) (Relationship Between Above-and Below-Ground Biomass for Norway Spruce (Picea abies) : Estimating Root System Biomass from Breast Height Diameter)

  • 이도형
    • 한국산림과학회지
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    • 제90권3호
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    • pp.338-345
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    • 2001
  • 본 연구는 독일가문비나무의 지하부인 뿌리구조와 지상부인 수관과의 상호관계를 밝혀, 어렵게 뿌리를 굴취하거나 침엽 생체량을 측정하지 않고도 수고와 흉고직경에 의한 상대적인 뿌리와 침엽 생체량 추정을 위한 회귀식을 구하기 위하여 실시하였다. 독일 중부 Harz 지방의 Barbis 임분에서 30~40년생의 우세목 5본과 준우세목 3본을 선발한 후 조사목의 지상부에 대하여 수고, 흉고직경, 지하고, 침엽량, 가지량, 횡단면, 변재면 등을 조사하였다. 그리고 5본에 대해서는 지하부의 뿌리길이, 뿌리수, 뿌리무게, 뿌리횡단면 등을 수평과 수직뿌리로 구분하여 조사하였다. 조사된 염분에서 독일가문비나무의 지상부(수고, 흉고직경, 침엽량, 가지량 등)와 지하부(뿌리길이, 무게, 수, 횡단면 등) 생체량 사이에는 서로 밀접한 상관을 나타내었다. 측정이 용이한 흉고직경에 대한 지하부 뿌리생체량은 Y = 3.56X - 45.94의 관계식으로 결정계수가 0.96으로 매우 높은 상관관계를 나타내었다. 가지량, 침엽량과 수고에 있어서도 지하부 생체량과 높은 상관관계를 나타내었다. 본 연구에서 얻어진 회귀식은 30~40년생 독일 가문비나무 임분에서 흉고직경을 이용하여 지하부의 상대적인 뿌리 생체량을 추정하는데 유용하게 이용될 수 있을 것이다.

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10년간 우리나라 운항승무원의 혈중 지질과 관련요인 분석 (10-Year Analysis of Blood Lipid Profile and Other Risk Factors Among Aircrew Members in Korea)

  • 곽인호;이용호
    • Journal of Preventive Medicine and Public Health
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    • 제26권3호
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    • pp.387-399
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    • 1993
  • This study was conducted to analyze blood lipid profile and other risk factors among crew members who are currently active and had more than 10 years of experience as crew members. Data was analyzed using medical record files in an airline medical department. The results are as follows. 1. The total number of crew members studied was 392. Among age groups, those below age 40 consisted of 26(6.9% of the total), those in age $41{\sim}50$ were 135 (34.4%) and those over age 51 were 230 (58.7%). 263 were former air force pilots consisting 66.9%. Those who had captain status numbered 21 I comprising 53.7% of the total. The type of aircraft most of the crew members involved were large size aircraft which totaled 268 (68.2%). With respect to the number of working years as crew members, 488(48.9%) comprised the largest group with $11{\sim}15$ years. 2. The rate of smoking among crew members has shown gradual decrease with 50.3% smoking in 1983 to 33.6% in 1993. Among $41{\sim}50$ age group the rate has shown a decrease from 20.9% to 13.3% In those group over age 51 it decreased from 25.5% to 16.6%. But group below age 40 were within the range of 3.6~3.8% with no significant change in the rate of smoking. 3. Body Mass Index in age group over 51 was slightly higher than other age groups. On the whole, BMI over 25 was not found. 4. The total cholesterol levels of those below age 40 were $196.9{\pm}38.5mg/dl,\;216.2{\pm}39.2mg/dl$ in ages $41{\sim}50$, and $225.1{\pm}42.5mg/dl$ in age group over 51. No significant difference was found among age groups. 5. HDL-cholesterol levels of over age 50 were higher than other age group and ranged from $40{\sim}55mg/dl$. 6. LDL-cholesterol levels of those over 51 were $126.7{\pm}37.7mg/dl$ higher than other age groups. But there were no significant changes in all age during 10 years of follow up. 7. Cardiac index of age group below age 40 was 3.8, 4.3 in age group $41{\sim}50$ and 4.5 in those over age 51 group. No significant changes among groups were found during the follow up period. 8. Triglyceride levels of age group below age 40 was $142.2{\pm}70.1,\;167.3{\pm}77.5$ in age group of $41{\sim}50$ and $113.6{\pm}897$ in age group over 50 showing that triglyceride levels increased with age. No significant changes in pattern were noted.

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광중합형 복합레진의 중합시간과 거리에 따른 중합도의 변화 (A STUDY ON THE CHANGES IN POLYMERIZATION OF LIGHT-ACTIVATED COMPOSITE RESIN WITH VARIOUS EXPOSURE TIME AND DISTANCE)

  • 안명기;정태성;김신
    • 대한소아치과학회지
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    • 제28권2호
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    • pp.293-299
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    • 2001
  • 본 연구에서는 광중합형 복합레진을 대상으로 중합거리와 시간의 변화에 따른 중합도와 거리에 따른 적절한 중합시간을 알아보기 위하여 일정 중합 광도하에서 중합거리와 시간을 달리하여 재료의 표면과 2mm 하방의 미세경도를 측정한 후 이를 통하여 간접적으로 중합도를 평가하였다. 광중합형 복합레진으로 Z100과 Z250을 사용하였고 각 재료별로 조사단과의 거리가 0, 2, 4, 6mm인 상태에서 20, 30, 40, 60, 80초간 광조사를 시행하였다. 중합 후 표층과 내층의 경도를 미세경도 측정기로 측정하였다. 측정치를 통계처리하여 다음과 같은 결과를 얻었다. 1. 거리의 증가에 따라 상대광도는 2mm이상에서 급격히 감소하였다(p<0.05). 2. 미세 경도는 상대광도와 조사시간의 증가에 따라 표층 및 내층에서 모두 증가하였다(p<0.05). 3. 내층이 표층에 비해 상대적으로 중합거리와 시간의 영향을 많이 받았다(p<0.05). 4. 조사 시간의 증가에도 불구하고 Z100 시편에서 중합거리가 4mm 이하군과 6mm군에서, Z250 시편에서는 2mm 이하군과 4mm 이상군에서 내층의 미세 경도 차이가 비교적 크게 나타났다(p<0.05).

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강원지역 1영급 금강소나무에 대한 천연림과 인공림의 지상부와 지하부 상관관계 (Correlation of Above- and Below-ground Biomass Between Natural and Planted Stands of Pinus densiflora for. erecta of One Age-class in Gangwon Province)

  • 나성준;김장수;우관수;김혜진;이도형
    • 한국산림과학회지
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    • 제100권1호
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    • pp.42-51
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    • 2011
  • 본 연구는 강원지역 1영급 금강소나무를 대상으로 천연적으로 갱신된 임분과 인공식재에 의해 성립된 임분의 지상부와 지하부 생체량간 상호관계를 비교 분석하고, 성립방법과 생육환경이 상이한 1영급 금강소나무의 임목 생체량 추정에 적합한 회귀식을 구하기 위해 실시하였다. 두 지역에서 각각 생육중인 천연갱신된 임목과 인공조림된 임목을 각 10본씩 전체 40본을 굴취하여, 수고와 근원직경, 지상부 각 부위별 건중량을 측정하였으며, 지하부인 뿌리에 대하여 주근과 수평근으로 구분하여 각각 길이, 무게, 재적을 조사하였다. 지상부와 지하부 상관관계에서 임분의 성립방법과 생육환경에 따라 다소 차이가 있었지만, 천연림과 인공림 모두에서 수고를 제외한 지상부 인자들은 뿌리 길이를 제외한 대부분 인자들과 밀접한 상관을 나타내었다(p< 0.05). 특히 임목에 있어 측정이 용이한 근원 직경은 모든 조사 임분에서 지상부와 지하부가 높은 상관관계를 나타내어(p< 0.01) 각 지상부 생체량 뿐만 아니라 지하부 생체량 추정에 적합한 인자인 것으로 나타났다. 반면, 수고는 대부분의 지상부와 지하부 인자들과 낮은 상관을 보여, 강원지역 1영급 금강소나무의 임목 생체량 추정에 사용되는 변수로서 미흡한 것으로 나타났다. 또한 본 연구에서 얻어진 회귀식은 근원직경을 이용한 지상부 및 지하부의 생체량 추정에 기초적인 자료로 유용하게 이용될 수 있을 것이다.

주택의 조명과 거주자의 면경착용 실태조사연구 (A Study on the Illumination of Household and Research on the Actual Conditions of Wearing Spectacles in Dwellers)

  • 석호작;남철현
    • 한국환경보건학회지
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    • 제17권2호
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    • pp.54-66
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    • 1991
  • As a result of measuring illumination and making up a question at home visit directly by investigator who trained over twenty days period from October 4 to 24, 1990, in order to render help which illumination problem against house, society against eyes or framing of health instruction potgram by seizing natural lighting actual conditions of house and actual conditions of wearing spectacles and by investigating interrelationship, I can summarize as follows. 1) In property of investigation subject, woman 66.9%, In an age, the twenties was largest of 27.4%, the forties was 20.2%, the fifties was 18.6%, the thirties was 17.4%. In academic career, those of upper secondary school grauates was largest of 28.6%, those who possess university career was 25.9%, those who middle school career was 20.9%, decoding of Korean alphabet was 2%. 2) By a residence area, a big city was 43.3%, farming and fishing villages were 20.3%, the rest was a small town and the administrative office of town, township. In positon of house, the middle area was 43.6%, resident of suburb area was 38.0%. In form of house, a Korean-style house was 40.8%, a western-style house was 34.8%, an apartment house was 11.0%. In the a standard of living, the middle classes 77.2%, the lower classes were 15.3%. In residential house unit of area, from 21 to 30 unit of area was largest of 31.5%, from 10 to 20 unit of area was 19.9%, from 31 to 40 was 18.7%. 3) The wearing spectacles rate of study user was 44.1%. By the area, those who wearing spectacles was more than a half of 50.8% in the resident of big city area. As passing from the farm area to the city, that is being resident of big city was high wearing spectacles rate. In position of house, as being residence in central street showed high wearing spectacles rate. (central street was 51.5%, the middle area was 44.5% and the suburb area was 40.1%.) It seemed similarity difference a variable by position of house from wearing spectacles in standard of 1%. By form of house, wearing spectacles rate those who resident in apartment house was 49.5%, that rate those who resident in a western-style house was high of 49.0%, that rate those who resident in a Korean-style house was the lowest 39.0%. By social position of resident in room, in students case who study showed very high, as university students were very high of 62.3% idn wearing spectacles rate, middle and high school students 'were 50.0%, members of society were 47.6%, workers 20.3%. It seemed similarity difference from academic career in standard of 1%. By an age, the thirties was high of 54.1% in wearing spectacles rate, the twenties was 43.2%, the teenage was the lowest of 11.8%. 4) In illumination of study, over 200Lux was high of 40.1%. but below 99Lux which inappropriate illumination to see the books was 32.4%. Average by area, below 99Lux was 22.7% and over 400Lux was 50.0% in case of wooden floor. As examine by area, below 99Lux was high of 27.0% a case of wooden floor in the big city area, it was not good in illumination passing from the farm area(15.0%) to the city(19.0%). Average illlumination by area of the main living room below 99Lux was high of 37.5%, less than 200Lux was 58.5% of whole. In general, illumination of the main livingroom was inappropriate. By area, the big city was 32.5% below 99Lux, the middle and small city area were 33.8%, town and township area were 45.0%, farming and fishing area were 42.8%. By area, in the big city, illumination of study was 52.5% over 200Lux and 28.9% below 99Lux. In case of the middle and small city, study user of below 99Lux was 38.8% and over 200Lux was 46.9%. In case of the seat of town township, below 99Lux was 34.1% and over 200Lux was 39.7%. In case of farming and fishing area, illumination of study was 33.4% below 99Lux and 48.4% over 200Lux. It tends to high rate of inappropriate illumination. 5) By position of house, in case of wooden floor, less than 100Lux was 24.5% in central street. It was bad illumination than others position of house. In case of the main livingroom, less than 100Lux was 40.4% in the suburb area. It was bad iliumnation than others position of house. In case of study, less than 100Lux was 35.4% in the middle area, it was worse in illumination. In case of the main living room, is seemed similarity difference in standard of 1%. 6) By form of house, in case of wooden floor, illumination of less than 100Lux was 23.8% in a western-style house, it was bad illumination than others form of house. In case of the main livingroom, illumination of less than 100Lux was 47.4% in a Korean-style house, it was remarkably bad illumination than others form of house. In case of study, a Korean-style house was 38.8%, it was very bad illumination than others form of house. In case of the main livingroom and study, it seemed similatrity difference each as P < 0.01 and P < 0.05 in standard of 1%. 7) The wearing spectacles rate of those who use room of illumination over 400Lux was 40.7%, and that of those who use room of illumination less than 100Lux was 28.1%. It seemed similarity differecce in standard of 1%. 8) In period of wearing spectacles, 21.3% of total investigator-highest-was from before five years, 8.6% was from before three years. Among those who use of illumintion less than 99Lux, 34.0% began to wear spectacles from before two years 31.7% was from before five years, 30.3% was from before four years. It seemed similarity difference from period of wearing spectacles by illumination in standard of 1 %. 9) Among cause which sight grow worse, the first was that it was each 33.2% and 27.4% in response rate because watch TV nearly to wearing spectacles person and non-wearing person. The second was that a lot of seeing books was 25.3% in wearing spectacles person and response rate for dark illumination was 7.4% in nonwearing spectacles person. It seemed similarity difference in standard of 1%. (P < 0.01). 10) In experience which take medicine good for eyes, it was 50.1% in wearing spectacles person and 8.5% in non-wearing spectacles person. It seemed similarity difference in standard of 1%(P < 0.01). As we have seen above, inappropriate illumination can be a cause of wearing spectacles. Nevertheless, actually, is realities to indifferent against illumination of house. So it must learn knowledge about health obstacle of illumination through society instruction and school eduction against students as well as general residents. In case that natural lighting is inappropriate structural of house, we must be able to maintain appropriate illumination through artificial illumination. And so eyes which is core of human life have to be protected, related the authorities, related group, and all health medical personnel will organically cooperate with and make efforts.

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Saturn-S 약해발생요인구명에 관한 연구 : 제 2 보 함씨메트린 제초제에 대한 품종간 저항성차이 (Studies on Factors Affecting the Injury Caused by Saturn-S to Rice Plant II. Differential tolerance of rice varieties against herbicides combined with Simetryne)

  • 양환승
    • 한국작물학회지
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    • 제13권
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    • pp.93-105
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    • 1973
  • 수도품종 통일과 만경 또는 밀성을 공시하여 전주(전북대학교), 광주(전남농촌진흥원) 이리(전북농촌진흥원) 밀양(영남작물시험장)의 4개지역에서 SaturnS의 (Saturn 7%, G+Simetryne 1.5%G), 약량수준 10a당 2, 3, 4, 5kg에 따르는 저항성 및 그들 품종간 차이를 추구한 바 그 결과는 다음과 같다. 1. 전주에서 초기약해의 품종간 저항성차이는 고온하($30^{\circ}C$이상)에서 약량(3kg-5kg)이 높아지면서 현저히 나타났다. 즉 통일은 2kg까지는 안전하나 3kg 이상에서 약해가 나타나기 시작 그 후는 약량에 거의 정비례하여 약해는 증가되었고 만경의 약해는 5kg 수준까지도 인정할 수 없었다. 수량은 비닐하우스의 고온조건에 있어서는 SaturnS, Mamate 모두 3kg 수준까지 통일에 있어서 관행구에 비하여 통계적으로 유의차가 없었다. 대기온도 조건에 있어서 통일은 3kg 수준까지 유의차가 없었다. 만경은 5kg 시용수준까지 두 온도조건에서 모두 유의적인 수량감소가 없었다. 2. 광주에서 초기약해는 전주지구와 그 경향이 거의 비슷하나 약제처리 당시 최고온도가 전주지구보다 약 $4^{\circ}C$ 낮은 상태에서 처리되었던 바 약해정도가 다소경미하며 통일의 경우도 3kg 수준까지는 거의 안전하고 4kg-5kg으로 농도가 증대되면서 나타났다. 3. 만경에 있어서는 4kg수준까지 관행구에 대비하여 통계적으로 유의차가 없었다. 만경에 있어서는 5kg수준까지도 유의차가 없었다. 4. 이리에서는 2kg에서 4kg수준까지 초기부터 두 푸종 공히 전혀 약해를 인정할 수 없었다. 따라서 수량에 있어서도 약해에 의한 영향에서 온 감수는 없었다. 밀양에서는 전북농촌진흥원 포장을 제외한 전주, 광주지역보다 약해는 경미하며 밀성에 있어서는 5kg수준까지도 거의 약해가 없었으며 통일에 대한 약해도 5kg수준까지 매우 경미하다. 수량은 2kg에서 5kg 수준까지 만경 통일 다 같이 관행구에 비하여 수량감소가 없었다.

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저수온 양식 넙치 Paralichthys olivaceus의 Cryptocaryoniasis (Cryptocaryoniasis of cultured flounder, Paralichthys olivaceus in low temperatures)

  • 지보영;김기홍;박수일
    • 한국어병학회지
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    • 제10권2호
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    • pp.97-111
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    • 1997
  • 1995년 겨울 경북 구룡포에 있는 축제식 양식장에서 사육중이던 넙치(평균 체장 : 31cm, 평균체중 : 300g)에 백점병이 발생하여 대량 폐사를 일으켰다. 감염 넙치로부터 병리조직학적, 원인충의 형태학적 및 생물학적 특성을 조사한 결과, 아가미 및 지느러미의 병리조직학적 검사에서 많은 섬모충들이 상피 하층으로 뚫고 들어감으로써 기생 부위의 상피 세포와 점액 세포가 증식을 일으킨 것을 볼 수 있었고 병어의 지느러미, 체표 및 아가미에서 작은 백점을 나타낸 충체는 기생성 섬모충 Cryptocaryon irritans의 특징을 갖추고 있었다. 그러나 이 충의 증식 방법은 다분열증식법 이외에도 출아와 다분열을 혼합한 또하나의 증식법(혼합 증식법)을 가진 것으로 조사되었으며 수온 $16^{\circ}C$에서는 위와 같은 두가지의 증식 방법이 약 3대 2의 비율로 나타났고 다분열 증식형의 충체는 8~14일만에, 혼합 증식형의 충체는 13~15일 만에 각각 자충을 방출하였다. 수온 $12\sim24^{\circ}C$의 조건에서 염분 농도 범위 $0\sim35\%_{\circ}$$5\%_{\circ}$ 간격으로 조절하여 충체의 생존능력을 살펴본 결과 다분열 증식형의 총체는 $12^{\circ}C$에서 $30\%_{\circ}$이하, $16^{\circ}C$에서 $20\%_{\circ}$ 이하, $20^{\circ}C$에서 $15\%_{\circ}$이하 그리고 $24^{\circ}C$에서 $25\%_{\circ}$ 이하에서 각각 폐사된 반면 혼합 증식형의 충체는 $12^{\circ}C$에서 $20\%_{\circ}$ 이하, $16\sim20^{\circ}C$에서 $15\%_{\circ}$ 이하 그리고 $24^{\circ}C$에서 $25\%_{\circ}$ 이하에서 각각 폐사를 나타내어 저수온($12\sim16^{\circ}C$)에서 혼합 증식형의 충체가 다분열 증식형의 충체보다 다소 낮은 염분 농도에서 생존이 가능함을 보여주었다. 수온 $12\sim24^{\circ}C$의 조건에서 탈낭 소요 시간 및 탈낭률은 다분열 증식형의 총체가 $12^{\circ}C$에서 8일 및 30%, $16^{\circ}C$에서 6.5일 및 50%, $20^{\circ}C$에서 5.5일 및 75% 그리고 $24^{\circ}C$에서 7일 및 10%를 나타낸 반면 혼합 증식형의 충체는 $12^{\circ}C$에서 15.5일, $16^{\circ}C$에서 14일 및 76.6%, $20^{\circ}C$에서 12일 및 72.2% 그리고 $24^{\circ}C$에서 10일 및 31.6%를 나타내어 모든 수온 조건에서 혼합 증식형의 충체가 다분열 증식형의 충체 보다 탈낭 소요 시간이 길며 수온 $16^{\circ}C$에서 최고의 탈낭율을 나타내어 저수온에 다소 안정적인 것을 보여주었다.

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강산성차아염소산수와 초음파를 병용처리한 조미오징어 반가공품의 미생물 오염도 저감화에 관한 연구 (Study on Reduction of Microbial Contamination on Daruma by Combination Treatment of Strong Acidic Hypochlorous Water and Ultrasonic Waves)

  • 정원희;고준수;신일식
    • 한국식품위생안전성학회지
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    • 제30권2호
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    • pp.166-172
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    • 2015
  • 본 연구는 강산성차아염소산수(SAHW)와 초음파(UW)를 병용한 조미오징어 반가공품의 미생물 오염도 저감 기술을 개발하고자 수행되었다. SAHW의 유효염소농도는 $69.67{\pm}0.58ppm$, ORP는 $1071.33{\pm}4.16mV$, pH는 $2.79{\pm}0.05$이었다. 오징어 반가공품을 중량대비 20배의 SHS에 120분간 침지하였을 때 일반세균은 1.49 log CFU/g, 황색포도상구균은 1.32 log CFU/g 감소하였으며, 대장균은 검출한계 이하로 감소하였다. 오징어 반가공품 중량대비 10배의 SAHW에 120분간 침지한 경우, 일반세균은 2.69 log CFU/g, 황색포도상구균은 1.74 log CFU/g 감소하였으며, 20배의 SAHW에 120분간 침지한 경우, 일반세균은 3.62 log lCFU/g, 황색포도상구균은 3.22 log CFU/g 감소하였으며, 대장균은 검출되지 않아 SAHW가 같은 유효염소농도의 SHS보다 살균력이 높은 것을 알 수 있었다. SAHW 단독 처리만으로는 만족할 만한 미생물 저감효과를 얻을 수 없었기에 조미오징어 반가공품을 SAEW에 1차 침지 처리한 후, SAHW에 2차 침지 처리한 결과, 오징어 반가공품 중량 대비 20배의 SAEW로 60분 처리한 후, SAHW로 처리하였을 때는 중량대비 10배, 120분 처리, 중량대비 20배, 90분 처리로 일반세균수는 약 4.0 log CFU/g, 황색포도상구균은 규제치(log 2.0 CFU/g 이하) 이하로 감소하였으며 대장균은 검출되지 않았다. 초음파 세정기에 오징어 반가공품과 중량대비 20배의 TW, SHS, SAHW를 각각 넣어 UW 처리한 후 미생물 오염도를 조사한 결과, SAHW로 60분간 처리하였을 때 일반세균은 검출한계(< 1.00 log CFU/g) 이하로 감소하였으며 황색포도상구균은 규제치 이하로 감소하여 가장 좋은 저감효과를 나타내었다. 대장균의 경우, SAHW 10분간 처리로도 검출한계 이하로 감소하여 SAHW와 UW의 병용이 조미오징어 반가공품 미생물 저감화에 가장 효과가 좋은 것을 알 수 있었다.