• 한국식품과학회지
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• 제22권2호
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• pp.168-171
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• 1990

냉동크릴의 가공처리와 식용에 필수과정인 해동시, 각질로부터 육질에로의 불소이동속도 및 육질내 불소농도를 상온해동, 저온해동, 유수해동 및 초단파해동 등의 해동방법으로 측정한 결과는 다음과 같다. 해동방법에 따라 키틴질부위의 불소가 육질로 이동하는 불소이동속도와 불소이동량에 차이를 보였고, 해동시간에 따라 육질내 불소농도는 유의적으로 증가하였으며 해동완료 후 육질의 최종 불소농도는 탈각대조군인 냉동크릴육질의 불소농도보다 2-5배 정도 높은 값을 보였다. 따라서 크릴을 어획한 후에는 즉시 철저한 탈각처리를 통하여 육질로의 불소이동을 최대한 줄여야 하매, 탈각처리를 거치지 않은 생냉동크릴로 운반, 저장, 가증될 경우에는 최적해동방법을 모색하여 해동시의 불소이동을 최소화시켜야 할 것으로 생각되었다.

• 대한화학회지
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• 제16권1호
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• pp.40-45
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• 1972

An electron spin resonance study has been made on lysozyme in. frozen aqueous solutions irradiated with $_{60}Co$ r-rays in air at $77^{circ}K.$ Water resonances are dominant when the concentration and the temperature are both below 20% and $130^{circ}K$ respectively. More solute radicals are produced in the solution of higher concentration. Majority of the solute radicals results from direct hit of the radiation. The same types of radicals are induced at $77^{circ}K$ whether the substances are irradiated in the dry state or in frozen aqueous solution. Based on these results, it is assumed that the number of ESR centers produced by the secondary intermolecular radical reacions and stabilized in aqueous solutions may depend on the concentration of the solution, and the presence of water may facilitate the secondary radical reactions occuring in the solute molecules after heat treatment. Majority of the solute radicals above around $193^{circ}K$ are believed to react with oxygen to form peroxytype radicals. However, when the solution is subiected to heat-treatment at $265^{circ}K$ after irradiation at $195^{circ}K$ the peroxy-type resonance was not observed, suggestin that an appreciable amount of oxygen is condensed into the ice, at $77^{circ}K.$ in addition to the oxygen that has already been dissolved in solution and react with solute free radicals during the process of heat-treatment. When the solution contains $H_2O_2$, no water resonance but $HO_2$, type resonance was observed probably indicating that the radiation-induced OH radicals are trapped in $H_2O_2$ aggregates and react readily with $H_2O_2$ molecules to poroduce $HO_2$ type radicals even at $77^{circ}K.$.

• Clinical and Experimental Reproductive Medicine
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• 제18권1호
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• pp.81-87
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• 1991

There studies were carried for evaluation of the efficiency of freezing of hamster oocytes for use in a human sperm penetration assay. The hamster oocytes fully equilibrated in various cryoprotectant agents and inseminated with human sperm. After insemination with hamster oocytes, there was no difference in penetrated rates. Cumulus free oocytes equilibrated in 1.5M various cryoprotective agents and slowely cooled to temperature $-30^{\circ}C$ before rapid cooling and storage in nitrozen tank. After rapid thawing, survival rates of frozen oocytes according to cryo-protective agents were examined and the human sperm penetration assay with zona free hamster oocytes was conducted. 1. Survival rates of oocytes after cryoprotectants exposure have no significant difference (range 88-91%) and peneration rate was 51.1%. 2. Recovery and survival rate of frozen-thawed oocytes were 85.1 and 66.8%. There was no significant difference on cryoprotective agents. 3. Penetration rates of the frozen-thawed and intact oocytes were 69.0 and 77.0%, respectively. 4. Hamster oocytes cryopreservation provides a convenient way of supplying and trans-porting hamster oocytes for the assessment of the fertilizing potential of human spermatozoa.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제29회 추계학술대회논문집
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• pp.105-109
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• 2007

로켓 노즐 유동해석에는, 전산 유체 역학 코드와 결합된 동결 유동 해석, 화학 평형 해석, 화학 비평형 해석이 사용되어진다. 고온 로켓 엔진 노즐의 설계에서, 동결 유동 해법과 동일한 수치적 특징을 가지는 화학평형 해석은 노즐의 열역학적 최대 성능을 예측하는 효율적인 설계 도구가 될 수 있다. 본 연구에서는 30톤급 KARI 액체 로켓 엔진 노즐에 대하여 동결유동 해석 및 화학평형 유동 해석을 수행하였다. 유동 해석 결과에 기초한 30톤급 KARI 액체 로켓 엔진 성능 평가는 노즐에서의 열화학적 특성에 대한 이해와 노즐의 성능을 제공할 것이다.

• 한국식품위생안전성학회지
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• 제26권4호
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• pp.283-288
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• 2011

전국 17곳의 식품 냉장 냉동 창고를 대상으로 입고, 교차오염, 보관, 온도 및 기록관리 등 5개 대분류와 20개 세부평가항목으로 분류하여 위생관리 수준을 분석하였다. 5개 대분류 평가항목별 수준에 대한 빈도분석결과, 기록관 리가 가장 높은 수준으로 나타났고, 이어서 온도 및 보관 관리 항목으로 나타났으며, 교차오염관리가 가장 낮은 수준으로 나타나 이 항목이 냉장 냉동창고 위생관리 중 현장에서 가장 잘 수행되지 못하는 항목으로 추정되었다. 총점과의 상관분석결과 교차오염과 보관관리가 높게 나타나 이들 2항목을 잘 관리하는 업소 일수록 전체적으로 냉장 냉동창고 위생관리를 잘 수행하는 것으로 판단되었으며, 20개의 세부평가항목 중 "교차오염과 관련한 발송시 교차 오염 방지를 위한 포장 여부"가 평균 $2.67{\pm}1.80$로 가장 낮게 나타났다.

• Asian-Australasian Journal of Animal Sciences
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• 제19권12호
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• pp.1716-1721
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• 2006

The present study was conducted to observe the effect of osmolality of glycerolated TEST-yolk glycerol extenders on post-thawing sperm kinematics of ram spermatozoa of the native Malpura breed maintained in a semi-arid tropical environment. Good quality semen obtained from adult rams was pooled, split and diluted to 1,000 million spermatozoa per ml in complete TEST-yolk-glycerol extenders of 900, 1,200, 1,500 and 1,800 mOsm/kg osmolality. Diluted semen samples were loaded in 0.25 ml straws and cooled down to $-125^{\circ}C$ freezing temperature at the rate of $-25^{\circ}C$ per minute under controlled conditions before plunging into liquid nitrogen for storage. The thawing of straws was performed at $50^{\circ}C$ in a water bath for 10 seconds and sperm kinematics of the frozen-thawed spermatozoa were assessed by a computer-assisted sperm analysis technique. Osmolality of diluent had no significant effect on post-thawing % motility, % rapid, % medium and % slow moving frozen-thawed spermatozoa but significantly (p< 0.05) affected the % linearity and % straightness. The post-thawing % motility and % rapid motile spermatozoa were highest in samples extended in diluent of 1,500 mOsm/kg osmolality and lowest in 900 mOsm/kg. The curvilinear velocity of spermatozoa was significantly (p<0.05) higher for samples extended in 1,800 mOsm/kg, compared to those in 900 and 1,200 mOsm/kg, but the effect was not significantly different to those extended in diluent of 1,500 mOsm/kg osmolality. The study indicated that ram spermatozoa could tolerate a wide osmolality range for dilution in the complete TEST-yolk-glycerol extender for their cryosurvival. The highest recovery of motile spermatozoa following thawing was achieved in samples extended in the TEST-yolk-glycerol diluent of 1,500 mOsm/kg osmolality.

• 한국분무공학회지
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• 제8권2호
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• pp.1-6
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• 2003

The liquid phase LPG injection (LPLI) system (the third generation technology) has been considered as one of the next generation fuel supply systems for LPG vehicles, since it has a very strong potential to accomplish the higher power, higher efficiency, and lower emission characteristics than the mixer type(the second generation technology) fuel supply system However. when a liquid LPG fuel is injected into the inlet duct of an engine, a large quantity of heat is extracted due to evaporation of fuel. This leads to freezing of the moisture in the air around the outlet of a nozzle, which is called icing phenomenon. It may cause damage to the outlet nozzle of an injector or inlet valve seat. In this work, the experimental investigation of the icing phenomenon was carried out The results showed that the icing phenomenon and process were mainly affected by humidity of inlet air instead of air temperature in the inlet duel. Also, it was observed that the total ice formed around the nozzle weighs at about $150mg{\sim}260mg$ after injection for ten minutes. And some fuel species were found in the ice attached at the front side of a nozzle, while frozen ice attached at the back of a nozzle was mostly' consisted of moisture of inlet air. Therefore, some frozen ice deposit. detached from front nozzle of an injector, may cause a problem of unfavorable air fuel ratio control in the small LPLI engine.

• Safety and Health at Work
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• 제6권1호
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• pp.56-61
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• 2015

Frozen food processing workers work under a cold environment which can cause several adverse health effects.This study explored factors affecting workers' health in the frozen food industry in Thailand. Participants comprised 497 workers exposed to a cold working environment and 255 office workers who served as the controls. Data were collected by a survey on the work environment, and the interview of workers for abnormal symptoms. The exposed group had the following characteristics: 52.7% male, overall average age of 27 (SD 6.6) years old, attained elementary education (Grade 4 and Grade 6) (54.1%), married (48.9%), smokers (21.3%), alcohol consumption (31.0%), duration of work was between 1 and 5 years (65.2%), working 6 days a week (82.7%), 1-5 hours of overtime per week (33.8%), office workers (33.9%); work category: sizing (6.9%), peeling (28.3%) dissecting (22.2%), and in the warehouse (8.6%). The temperature in the work environment ranged from $17.2^{\circ}C$ to $19.2^{\circ}C$ in most sections, $-18.0^{\circ}C$ in the warehouse, and $25^{\circ}C$ in the office areas. Warehouse workers had more abnormal symptoms than controls including repeated pain in the musculoskeletal system (OR 11.9; 95% CI 6.12-23.45), disturbance throughout the body (OR 4.60; 95% CI 2.00-10.56), respiratory symptoms (OR 9.73; 95% CI 3.53-26.80), episodic finger symptoms (OR 13.51; 95% CI 5.17-35.33). The study results suggest that workers' health should be monitored especially with regard to back and muscle pain, respiratory symptoms, episodic finger symptoms, and cardiovascular symptoms. Health promotion campaigns such as antismoking and reduction of alcohol consumption should be established because smoking and alcohol consumption are contributing factors to the pathogenesis of Raynaud's phenomenon and peripheral vascular disorders such as hypertension and heart disease.

• 한국식품과학회지
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• 제33권1호
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• pp.45-49
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• 2001

본 연구는 single-screw extrusion puffing을 이용하여 동태, 탈지콩가루의 양은 고정시키고, 쌀가루와 옥수수가루의 함량을 달리하여 제조한 압출 성형제품의 특성을 알아보고자 실행하였다. 각 제품에 있어 일반성분에서의 통계적인 차이는 나타나지 않았으며 품질특성에서는 쌀가루 100%로 제조한 제품이 다른 제품과 비교했을 때 팽화율이 높고, 밀도가 낮으며 전단력이 가장 낮게 나타나 유의성 있는 차이를 보여주었다(P<0.05). 100% 쌀가루제품이 색도에서도 명도가 가장 높았고, 관능검사의 전반적인 바람직성 검사에서도 선호도가 높게 나타났다. 결론적으로 수산식품인 동태와 탈지콩가루를 쌀가루에 첨가하여 옥수수가루보다 팽창이 잘된 압출성형제품을 전단력이 낮은 좋은 조건에서 생산할 수 있었다. 이 결과는 차후 제품 개발에 동태를 첨가시킨 쌀가루 스낵제품을 만들 수 있는 기초자료가 될 것으로 사료된다.

• 한국식품과학회지
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• 제30권4호
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• pp.842-847
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• 1998

Ohmic heating은 식품에 교류 전류를 흘려줄 때 식품 내부에 전기 저항열이 발생되는 것을 이용한 것으로, 이를 기존의 수해동법에 적용하여 해동시간의 단축과 그에 따른 품질 향상 효과를 연구하였다. 자체 제작한 ohmic 수해동 장치에 동결육$(10{\times}10{\times}10{\;}cm)$을 넣고 해동 실험하였다. 윗면이 개방된 acryl box$(12{\times}12{\times}12{\;}cm)$를 용기로 사용하였으며, stainlesssteel 전극$(10{\times}10{\;}cm)$을 양쪽 벽면에 설치하였다. 용기 내 물의 온도를 $20^{\circ}C$ 또는 $10^{\circ}C$로 고정하였다. 해동시간은 동일한 주파수(60 Hz)에서 전압을 높여줄수록$(60{\sim}210{\;}V)$ 단축되었으며, 수해동만을 한 경우에 비해 최고 1/4 이상 단축되었다. 동일한 전압에서 주파수가 높아질수록 $(60{\sim}60{\;}kHz)$ 해동시간이 단축되었으나 그 효과는 크지 않았다. 수해동만을 한 경우나 높은 전압을 적용한 경우보다 낮은 전압을 적용한 경우 drip loss가 적었고 보수력이 우수하였다.