초고온용 안테나 덮개의 기계적 특성 시험결과

김재하,황동기,최대근,Kim, Jai-Ha,Whang, Dong-Kee,Choe, Dae-Geun 한국군사과학기술학회 2007 한국군사과학기술학회지 Vol.10 No.4

This paper considers the mechanical properties test results of the ceramic fiber reinforced plastic using hyper temperature. These materials were developed to make antenna cover which should not only protect antenna from high temperature and high pressure but also transmit and receive radio frequency for hypersonic missile. So the bending strength tests under the room temperature and the hyper temperature for new materials were done to evaluate of their performances. Also, the conductivity, specific heat, diffusivity and density were tested.

측추력을 이용한 초기방향전환 및 고고도 고기동 유도탄 설계

김재하,한상설,이동주,송경록,Kim, Jai-Ha,Han, Sang-Sul,Lee, Dong-Ju,Song, Kyoug-Rok 한국군사과학기술학회 2013 한국군사과학기술학회지 Vol.16 No.2

This paper considers the many kinds of attitude control systems including launcher. JVC(Jet vane control), Jet tap, Jetvator and Movable nozzles are used to control the initial attitude of a missile only. Recently side jet thruster and it's applications to control initial turn and to maneuver at high altitude have been increased. How to design and develop the missile for an initial turn and a high maneuver at high altitude using side jet thrust were described in this paper.

뻐터내의 지방함량측정에 있어서의 한 실용적 방법

김재하 ( Jai Ha Kim ) 한국축산학회 1978 한국축산학회지 Vol.20 No.5

Three direct methods (refractive index and weighing method, Tergitol method, and filtering method) for the determination of percentage fat in butter were investigated. For the refractive index and weighing method, the accuracy of the determination of percentage fat was predicted by calculating the theoretical changes in refractive index of fat-solvent mixture and in the weight of 5 ㎖ of mixture for a unit change in the fat percentage in butter. Because of the low accuracies predicted by the calculation and the toxicity of solvents used, this method was not used for further investigation. The fat percentages of seven samples were determined by the Tergitol method and compared with the Mojonnier method for accuracy and time requirement. The precision was ±0.2091 for the Tergitol and ±0.0766 for the Mojonnier method, but the former required only 30-35 minutes while the latter required 40-45 minutes for duplicate analyses. The Tergitol method is as simple as the Kohman method and permits more analyses to he conducted simultaneously with a given amount of space and equipment. If any device or technique which would reduce the final reading error could be achieved, this method could be practical for measuring the fat content of butter during the manufacturing process. For the filtering method an attempt was made in a preliminary investigation to determine its feasibility, and in further investigations an attempt was made to modify the initial procedure in order to reduce the time requirement with a minimum sacrifice of accuracy. The effects of drying temperature, cooling time, drying method and amount of sample on accuracy and time requirement were investigated. The initial conditions of loser temperature (80℃) drying in a convection oven and adequate time (20 minutes) for cooling in an aluminum desiccator gave results with a standard deviation of difference and a mean difference from the Mojonnier method of ±0.1782 and -0.002 respectively and a precision ±0.1375. However, this procedure took approximately 50 minutes and this was considered to be too time-consuming to be practical for a test during the manufacture of butter. Drying at higher temperature resulted in a saving of time, and a loss of accuracy. The time allowed for cooling the dried fat and its container had an effect on the accuracy of the results but the accuracy achieved after 10 minutes cooling was as good as that achieved after 20 minutes cooling. To reduce the time requirement for the drying an infra-red heat lamp was used instead of a convection oven, and this would found to be a satisfactory method for fast drying. Two types of balance, an analytical balance and a moisture balance, were used for the final weighing. Using the analytical balance gave much better accuracy. The determination could be done in 20 minutes with the moisture balance and in 20-25 minutes with the analytical balance. Two different amounts of sample (1g and 5g) were tried when using the analytical balance. Better results were obtained with 5g samples although 25 rather than 20 minutes was required for a single analysis. When using the analytical balance for weighing, the infra-red lamp for drying, and 5g samples, the standard deviation of difference. form the Mojonnier method was ±0.2846, the mean difference was -0.012, and the precision was ±0.1028. This procedure was considered to be the most suitable filtering procedure for the determination of percentage fat in a creamery due to the relatively accurate results and the shorter time requirement. When compared with the presently available Kohman method, it gave slightly less accurate results, but the times required for determinations with these two methods were the same. For the Kohman method, the precision was ±0.0946, and the standard deviation of difference, and mean difference from Mojonnier results were ±0.1398 and ±0.031 respectively.

식중독의 중요성과 이에 대한 Canada 정부의 대책

김재하 ( Jai Ha Kim ) 한국축산학회 1978 한국축산학회지 Vol.20 No.5

It was reviewed what food-borne diseases are, how significant it is, how they are spread, what is the present Canadian situation in this aspect, and what Canadian governments are doing and what endeaver and suggestions are made in an effort to minimize the outbreak of this disease. Recently, recognition of the diseases from microbiological contamination of foods has led to national and international attention in which public health problems have been brought sharply into focus. Some of these are: 1. Despite renewed interest in microbial contamination of foods which endangers public health, current efforts are inadequate to cope with problems associated with rapid changes and new developments in the food supply. 2. The reports of food-borne diseases which submitted to the federal health protection branch by each provinces are only a small part of actual incidences occurred in Canada. Therefore, more thorough investigation and more consistent reporting of these illnesses are needed for the guidance by industry and government in their efforts to protect the public health. 3. Improved methods in microbiological test and rapid methods for isolation of microbes are needed for the establishment of more advanced standard procedures. 4. Continuing evaluation of food protection programs and practices is necessary to keep them abreast of the technological changes. 5. Wide national and international research and educational programs are necessary to promote new knowledge, technology and public understanding for the prevention of food-borne diseases. To solve above problems, following cooperative activities could be proposed as a national program of food protection. 1. Improvement in the investigation and reporting of food-borne disease by: a. Generating more active participation on the part of practicing physicians, through special education and encouragement by medical organization as well as public health agencies. b. Developing greater interest and teamwork among health department personnel by improve leadership, education, and support from the Public Health Service. c. Devising better techniques for the epidemiological study of disease outbreaks. d. More detailed analysis of reported illnesses and publication of findings in a form that will encourage prevention and control by industry. e. Centralization of responsibility in one component of the Public Health Services environmental health structure. 2. Continuous surveys of potentially hazardous foods for objectionable microbial contaminants. 3. Modernization of food protection programs and practices. 4. Major expansion of research and education in food microbiology as well as all other fields concerned with the relation of food to health. It is further recommended that special study be given the evaluation of microbiological hazards associated with new food products and technologies. This study should particularly include microbiological study in the early phases of process development and of distribution and marketing of new products. Finally, before general microbiological specifications, limits, or standards are formulated, it is recommended that surveys of the various branches of industry be made to determine attainable levels of microbiological contamination of foods under conditions of good commercial practice.

전자기 및 광학 센서를 적용한 무기체계의 강수 운용규격 설정을 위한 한반도 강수량 분포에 관한 연구

이동주,김재하,Lee, Dong-Ju,Kim, Jai-Ha 한국군사과학기술학회 2010 한국군사과학기술학회지 Vol.13 No.2

When a weapon system is developed, climate elements such as temperature, rainfall, and so on have an effect on development costs and a developing period. Therefore, effects of environment and climate must be examined throughly before the design of weapon systems and be applied to their developments. And so, operational and storage requirements for weapon systems are determined and are applied to related tests through analyzing not only environmental factors such as vibration, shock, and so on, but also climate factors. In this paper, the distribution and the frequency of occurrence of rainfall were analyzed and were suggested as a good guide to determine standards of tests for weapon systems when it's raining.

放射線照射에 依한 柑橘 貯藏에 關한 硏究

정창조(Chang Cho Chung),김재하(Jai Ha Kim),김수현(Soo Hyun Kim),조한옥(Han Ok Cho) 한국식품영양과학회 1983 한국식품영양과학회지 Vol.12 No.2

柑橘의 貯藏性 向上을 위한 (60)^Co-γ線 照射가 濟州産溫州柑橘에 미치는 影響을 調査하였다. 溫州柑橘 4個 系統을 10.000Ci, (60)^Co-γ線源을 利用 0, 50, 100, 150Krad 水準으로 照射하여 22日間 半地下地 貯藏庫에 貯藏 調査한 結果를 要約하면 아래와 같다.<br/> 1. 貯藏終了時까지의 柑橘ㆍ累積腐敗率은 中生系인 米澤(T₂)74.32%, 早生溫州(T₁)69.67%, 中晩生系林溫州(T₃)61.79%와 晩生系 靑島(T₄)가 64.33%였다. 反面 서울 地域의 腐敗率은 貯藏72日에서 T₁:28%, T₃;25% T₄;24%로 濟州地域에 比해 越等히 낮았다. 柑橘이 腐敗는 貯藏初期에 徐徐히 增加하나 照射後 59日 부터는 急激히 上昇하기 시작하였다. 腐敗率과 柑橘系統 사이에는 高度의 상관관계가 있었으며 貯藏性은 T₃와 T₄가 가장 우수하였다. (T₂:ŷ=0.78x-15.30, T₄;ŷ=0.79x-12.29, T₁;ŷ=0.93x-9.01, T₂;ŷ=0.79x-13.49)<br/> 放射線 高照射水準(100, 150krad)은 貯藏中期까지 柑橘貯藏에 效果가 있었으나 照射 79日 以後에는 對照區와 差가 없었다.<br/> 2. 放射線 照射는 貯藏期間中 柑橘의 酸度를 減少시켰으며 平均酸度는 T₁;1.01%, T₃;1.01%, T₄;0.84% 및 T₂;0.77%로 柑橘系統 및 照射線量 間에는 높은 (p<0.01) 有意差가 認定되었다.<br/> 3. 모든 處理區에서 還元糖과 全糖含量은 增加하고 있었으나 統計的 有意性은 없었고 50krad 調査區에서만은 對照區에 比해 有意的(p<0.01)으로 減少하고 있었다.糖度는 T₁, T₄가 T₂, T₃에 比해 높았으며 高線量水準(100, 150krad)에서 對照에 比해 有意的인 減少가 있었다(p<1.01) ascorbic acid의 含量은 모든 處理區에서 貯藏時期가 經過됨에 따라 減少하였으며 高照射線量 水準에서 對照區에 比해 有意的인 減少가 있었다(p<0.01) A study was conducted to evaluate the effect of (60)^Co-γ irradiation on the preservation on Satauma mandarin in Cheju Island. Four varieties (S. m. early, S. m. Komezawa, S. m. Hayashi and S. m. Aoshima) were irradiated using 10, 000Ci, (60)^Co-γ ray with dosages of 0, 50, 100 and 150Krad. During 92days of storage the effects of irradiation on mandarin porperties were as follows:<br/> At the end of storage period the accumulated fruit rotting percentage were S. m. Komezawa(T₂) ; 74.32%, S. m. early(T₂) ; 69.67%., S. m. Aoshima(T₄) ; 64.33% and S. m. Hayashi (T₃) ; 61.79%. The rottings steadily increased from the early stage of storage and rapid spoilage continued after 59 days of irradiation. A high corelation existed between fruit rotting and varieties (T₃; Y=0, 78x-15.30, T₄; Y=0.79x-12.29, T₁;Y=0.93x-9.01 and T₂;Y=0.79x-13.49)<br/> High dosages(100 and 150 Krad)improved fruit preservation during the mid storage stage. However 76 days after high dose irradiation there was no significant difference a rotting between irradiated fruit and the control.<br/> Irradiation decreased acidity of fruit during storage (p<0.01). The mean acidities of examined varieties were T₁;1.01%, T₃;1.01%. T₄;0.84% and T₂;0.77%. A significant differences were observed in acidity between varieties and dosages(p<0.01)<br/> With one exception in all treatments. the increase in free and total sugar content was not statestically significant. The exception was the 50 Krad treatment where the total sugar content decreased. T₁ and T₄ showed slightly higher value of than Brix T₂ and T₃, and were significantly(p<0.0l) decreased by higher dosage. The ascorbic acid content in all treatments decreased with length of storage and also decreased significantly with a higher dosage.

γ-ray 조사에 의한 제주산 양파의 발아 및 성분변화

Yong-Bong Park(박용봉),Jai-Ha Kim(김재하),Ki Taek Kim(김기택) (사)한국생물환경조절학회 2000 시설원예‧식물공장 Vol.9 No.4

290 ksi 급 고강도강의 고온 인장특성

윤용근(Yong-Kwen Yoon),김재훈(Jae-Hoon Kim),정동희(Dong-hee Joeng),박성호(Sung-ho Park),김재하(Jai-Ha Kim) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.4

해조류 용매별 추출물의 항돌연변이원성

김봉오,박제석,오명철,현재석,김재하,오창경,김수현 濟州大學校工科大學産業技術硏究所 1996 尖端技術硏究所論文集 Vol.7 No.2

톳, 미역 및 다시마를 용매별로 추출하여 이들 추출물의 항돌연변이원성을 검색하였다. 톳 용매별 추출물의 MMS에 대한 항돌연변이 효과는 TA100 균주에서 헥산, 에탄올, 에칠에테르 추출물 순으로 높았고, TA102 균주에서 헥산, 에칠에테르, 에탄올 순으로 높았으나, 미역 및 다시마 추출물은 항돌연변이원성이 거의 없었다. ICR191에 대한 항돌연변이 효과는 시험된 모든 시료에 대한 에탄을 추출물이 높은 항돌연변이 효과를 나타내었고, 에칠에테르와 헥산 추출물은 물 추출물보다도 낮은 효과를 나타냈다. 그러나 톳 추출물은 시험된 모든 용매 추출물에서 60% 이상의 높은 항돌연변이 원성을 나타내어 ICR-191에 의해 유도되는 돌연변이 원성을 저해하는 물질이 수용성 및 비수용성에 걸쳐 다양함을 나타내었다. 한편, 미역, 다시마 및 톳 추출물의 sodium azide에 대한 항돌연변이원성은 없는 것으로 나타났다. Desmutagenic effects against methyl methanesulfonate(MMS)-, 2-methoxy-6-chloro-9-〔3-[2-chloroethyl〕aminopropylamino〕acridine(ICR191)- and sodium azide-induced mutations by the extracts from Hizikia fusiforme. Laminaria japonica and Undaria pinnatifida with different solvents were investigated. The solvent extracts from Hizikia fusiforme were the highest desmutagenic effect against MMS in n-hexane and against ICR191 in ethanol extract. but no against sodium azide in all solvent extracts tested. While the solvent extracts from Undaria pinnatifida and Laminaria japonica were the highest against ICR191 in ethanol extract. but no against sodium azide and MMS in all solvent extracts tested. Moreover. all the solvent extracts from Laminaria japonica were inhibited 60% or more ICR191-induced mutations.

放射線照射에 의한 濟州産 鹽乾옥돔의 貯藏性向上에 관한 硏究

金洙賢,鄭昌朝,趙韓玉,金在河 제주대학교 방사능이용연구소 1985 연구보고 Vol.1 No.-

濟州産 鹽乾옥돔(yellow sea bream ; Branchiostegus japonicus japonicus)을 Vinyl 眞空包裝 0, 0.5, 1.0, 1.5 및 2.0Mrad 水準으로 放射線 照射후 室溫과 冷藏으로 60日間 貯藏하여 鹽乾옥돔의 理化學的變化 및 官能檢査를 수행하였다. 貯藏期間中 總菌數는 放射線 照射水準이 높아짐에 따라 抑制되고 있었으며, 放射線照射와 冷藏處理가 더욱 效果的이었다. TMA의 增加率은 高線量水準에서 적었으며 2.0Mrad水準은 도리어 貯藏初期에 비하여 末期에 이르러 TMA의 含量을 減少시켰다. TMAO의 減少率은 貯藏條件에 관계없이 照射後 20日傾부터는 急激한 減少現象을 나타내었다. Total nitrogen의 減少는 無照射區에서 가장 컸으며, 照射水準이 높아짐에 따라 變化의 폭은 적었다. VBN含量은 各 處理區 모두 D30에서 顯著한 增加를 보이고 있었으며, 放射線處理에 따라 多少 抑制되었다. 放射線照査와 室溫貯藏區에서는 20日까지, 放射線照査 및 冷藏處理區에서는 40日까지 鹽乾옥돔의 鮮度를 유지시킬 수가 있었다. 組織變化, 總菌數, 腐敗 등 要因을 考慮할 때 鹽乾옥돔의 貯藏性向上을 위해서는 1.0Mrad가 適正水準으로 推定되었다. Salted dry yellow sea bream were vaccum packed in a plastic bags and irradiated at differents levels (0.0.5, 1.0, 1.5 and 20 Mrad) using ?? source. The irradiated samples were stored at room temperature and 5℃. Physical and chemical properties were examined during storage. The total bacterial count was depressed according to level of irradiation applied. It was noted that cold storage after irrdiation was more effective than room temperature. TMA contents slowly increased with higher dosage rates up to 1.5 Mrad but there was a gradual decrease of TMA at the 2.0 Mrad level.It was observed that there was a rapid decrease of TMAO 20 days after irradiation irrespective of storage temperature. The reduction of total nitrogen content was highest in the control but to a lesser degree when irradiation was applied. VBN content increased in all treatments 30 days after irradiation but it was also noted that there was a tendency toward depression of VBN by irradiation. The shelf life of salted dry sea bream was extended by 20 days with irradiation plus room temperature, and by 40 days with irradiation plus cold storage. To extend shelf life of salted dry sea bream, the most effective dosage rate was 1.0 Mrad based on tenderness, bacterial count and rancidity.