• 대한수의학회지
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• 제41권1호
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• pp.89-98
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• 2001

This study was conducted to detect the toxoplasma specific-DNA in circulating blood and organs collected from slaughtered pigs at slaughtering house and experimentally infected pigs with Toxoplasma gondii tachyzoites by polymerase chain reaction(PCR), and also PCR was applied to diagnose for acute phase of swine toxoplasmosis as a newly developed diagnostic test. The sensitivity of oligonucleotide primer, T-1 & T-2, designed from toxoplasma B1 gene amplification method was compared with Tp parasite detection by mouse inoculation(MI). On the other hand, latex agglutination test(LAT) was conducted to detect the serum antibodies comparing with the detection of toxoplasma by PCR and MI. The results obtained were summarized as follows. PCR was able to determine at the lowest level of $10^0/ml$ T. gondii in blood samples which were blended with a serial diluted T gondii in vitro. On the other hand, $10^2/5g$ of T gondii could detect from a variety of tissues including lung, diaphragm, liver, heart, spleen and brain in vitro. The primer was proved to specifically determine T gondii in blood and tissues in vitro but it did not detect Neospora caninum used as a negative control. DNA of T. gondii was effectively extracted by freezing, thawing and grinding twice both tissues mixed with T gondii in vitro and in experimentally infected pig's tissues. PCR detected specific DNA in the blood of experimentally infected pigs at 108 hrs and 120 hrs post-infection, it was the same time that the pigs showed fever and parasitaemia. In case of tissue, specific DNA was, however, detected only lung from experimentally infected pigs. Even though the duration of acute phase was from 3 to 7 days post-infection, but the latex agglutination test (LAT) results appeared from 8 days post-infection. A comparison of sensitivity in determining T gondii in blood samples between PCR and MI, PCR positive rate ranged from 25 to 33.3%, but that of MI covered from 75 to 100%.

• 대한기계학회논문집A
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• 제29권10호
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• pp.1416-1429
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• 2005

In order to meet the increasing competitive pressures coupled with higher demands for component quality, whirling machines have been at the cutting edge of the automobile industry for more than 25 years. The hard whirling process can save on machining time and operation elimination. Hard whirling is done dry, without coolant. The chips carry away nearly all of the heat during cutting, leaving the workpiece cool and minimizing any thermal geometry variations. The surface finish and profile accuracy are close to grinding quality. Whirling machines usually consist of four major parts; 1) loading system that requires the necessary axial speeds, 2) head stock that needs high precision clamping and positioning system at the chuck and tailstock, 3) whirling unit that demands the high cutting speeds and cutting power fer cutting deep thread profiles and 4) unloading system that requires an easy workpiece unloading. Also, capabilities of the whirling machine can be improved by attaching a vision system to the machine. Most of whirling machines in Korean automobile industry are imported from the Leistritz company, Germany and the Hasegawa company, Japan. Tn this paper, a basic research will be performed to improve and enhance the existing whirling machines. Finally, a new Korean whirling machine will be proposed and developed.

• 한국식품과학회지
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• 제24권5호
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• pp.404-407
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• 1992

이 연구의 목적은 식품성분의 분석을 위한 신속간편법으로 근적외선 반사 분광분석을 이용함에 있어 흡광도에 영향을 미치는 시료의 물리적, 화학적 요인을 규명하고자 한다. 온도를 달리한 정육시료를 근적외선 파장 범위인 $1100{\sim}2500\;nm$에서 흡광도를 측정한 결과 온도가 상승함에 따라 흡광도가 대체로 증가하였다. 시료의 세절시간이 길어질수록 흡광도는 감소하였다. 정육, 육단백질, 지방 및 수분의 근적외선 스펙트럼에서 나타난 흡수띠는 분자내의 C-H, N-H, O-H 및 C=O 결합의 overtone과 combination 진동에 의한 것으로 확인되었다. 정육 구성성분 중 육단백질의 흡광도가 가장 낮았으며 지방은 1700 nm와 2300 nm 부근에서 특징적인 ${\cdot}CH_2{\cdot}$ 흡수띠를 보였고 1450 nm와 1930 nm에서 물분자에 의한 강한 흡수띠가 나타났다. 결과적으로 정육의 근적외선 스펙트럼의 흡광도는 함유된 수분과 지방에 의한 영향을 많이 받는 것으로 사료된다.

• Restorative Dentistry and Endodontics
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• 제10권1호
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• pp.85-92
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• 1984

The aim of this study was to examine the influence of the speed of grinding and coolants on mercury vaporization during amalgam removal. Forty amalgam filled stone dies were stored at $37^{\circ}C$ and 100% relative humidity for 7 days prior to the beginning of the mercury vapor experiment and were divided into 4 different groups; In Group I; Used by high speed without coolant & evacuator during amalgam removal. In Group II; Used by high speed with coolant & evacuator during amalgam removal. In Group III; Used by low speed without coolant & evacuator during amalgam removal. In Group IV; Used by low speed with coolant & evacuator during amalgam removal. The amalgam specimens were removed in a 30-second time period and mercury vapor was collected with membrane filter at 27mm from the site of removal and 45 degree above there. Samples in Group II, IV were removed with coolant spray at a flow rate of 30 ml/min with high-velocity evacuator. Mercury vapor collected membrane filter was analysed by Atomic Absorption Spectrophotometer using cold vapor method. The results were as follows; 1. The mercury vapor levels were obtained all of the Groups. 2. The mercury vapor levels of the Group II, IV (with coolant & evacuator) were less than that of the Group I, III (without coolant & evacuator). 3. The highest mercury vapor level recorded during amalgam removal procedure was Group I (used by high speed without coolant & evacuator) and its record was $0.78{\pm}0.09\;mg/m^3$, which exceed the T.L.V. by 15 times. 4. The mercury vapor level of the Group IV (used by low speed with coolant & evacuator) was more than that of the Group II (used by high speed with coolant & evacuator), but its difference was not significant, statistically. (p > 0.05)

• 한국관광식음료학회지:관광식음료경영연구
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• 제12권2호
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• pp.1-41
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• 2001

The effect of smoking on the quality sausage Sausages were prepared from beef, port, chickens, games, fish and shellfish with polyphosphate salt and spices. Sausage history goes back to 3,000 years of age. The procedure of sausage 1) Meat Curing 2) Meat Control 3) Add Spices 4) Permissible Ingredients 5) Grinding 6) Mixing Emulsion 7) Stuffing 8) Showing 9) Smoking 10) Cooking 11) Drying 12) Packaging Sausage Product to get information on the effect of smoking onto the quality of meat produces. Sausage was smoked under a given conditions. Smoking was conducted as 35f$^{\circ}C$to 6$0^{\circ}C$ the related humidity of smokehouse was still at 60 to 70 percent. Results are as follows: 1. The Penetrated smoke in sausage was prolonged < p.<0.02 when sausage was smoked 2hours at 60~$65^{\circ}C$ the penetrated amount of free acetone in sausage was 0.5mg%. 2. Peroxide value of sausage as heating treatment both at 3$0^{\circ}C$ and at 5$0^{\circ}C$ was prolonged. 3. When sausage was heated at 3$0^{\circ}C$, bacteria of sausage increased In number while at 60~$65^{\circ}C$ bacteria of sausage increased In number fourteen hours. 4. When sausage was treated with smoking the distribution of free amino acids in sausage was changed markedly. 5. The longer smoking time of the products was the higher the content. 6. In case of oak wood smoke flavoring all of test samples. 7. Rapid decrease of does-response mutagenic curve of the smoke flavoring of oak wood and apple wood by in the peak of curve and phenol in the smoke flavoring. Continuous efforts are required to make sausages easily in the butcher shops and in the restaurants. 8. Sausage texture evaluation has 13 rules. It is Elasticity, Surface Moisture, Surface Smoothness, Center Hardness, Skin Toughness, Cohesiveness, Denseness, Moisture Release, Cohesiveness of Mass, Lumpiness, Graininess (of Contents), Skin separation, Oiliness and sensory 11 rules evaluation is color, texture, mold, flavor, sweet test, salty, sourness, bitter, and savory taste. 9. Smoked, component, peroxide value, bacteria, color, free amino acid, tenderness, flavor, shrinkage are important values.

• 한국건설관리학회논문집
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• 제7권5호
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• pp.149-158
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• 2006

종래의 깎기식 제거기에 의한 노면표시 제거작업은 인력에 의존하는 단순반복 작업으로 진행된다. 따라서 교통사고, 잔재제거에 사용되는 프로판 가스의 폭발, 작업자의 건강과 환경에 위해한 먼지와 유해가스 발생 등 위험요소가 상존하고 있다. 이러한 노면표시 제거작업의 문제점은 자동화 로봇화의 잇점으로 작용될 수 있다. 본 연구에서는 초고압수를 이용한 모바일 타입 노면표시 제거장비의 프로토타입을 개발하였다. 그 결과는 다음과 같다. 첫째, 현행 노면표시 제거작업 분석결과 노면표시 제거작업은 a)작업준비, b)노면표시제거, c) 현장정리로 구분할 수 있다. 이들 중 b) 노면표시제거작업의 전 공정을 수행할 수 있는 건설기 계장비가 필요함을 알 수 있었다. 둘째, 개발장비는 1일 8시간 작업 기준으로 약 1,400m를 작업할 수 있는 것으로 나타났다. 이 값을 기존방식의 작업량과 비교한 결과 280.0%의 생산성 달성 비율을 얻을 수 있는 것으로 분석되었다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 춘계학술발표대회
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• pp.3.1-3.1
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• 2009

Normal sintering process of producing porous ceramics is not to sinter perfectly, i.e., stop sintering in middle-process. Our porous ceramic materials are a product of complete sintering. For example if one want to make a porous carborundum, raw carborundum powder is sintered at either lower temperatures than normal sintering temperature or shorter sintering periods than normal sintering time to obtain incompletely sintered materials, i.e., porous carborundum. This implies normally sintered porous ceramic materials can mot be used in high vacuum conditions due to dust coming out from uncompleted sintering. We could produce completely sintered porous ceramic materials. For example, we can produce porous carborundum material by using carborundum particles bonded by glassy material. The properties of this material are similar to carborundum. We could make quasi-zero thermal expansion porous material by using carborundum and particles of negative thermal expansion materials bonded by the glassy material. We apply to sinter them also by microwave to sinter quickly. We also use HIP process to introduce closed pores. We could sinter them in large size to produce $2.5m{\times}2.5m$ ceramic plate to use as a precision plate for flat display industries. This flat ceramic plate is the world largest artificial ceramic plate. Precision plates are basic importance to any advanced electronic industries. The produced precision plate has lower density, lower thermal expansivity, higher or similar damping properties added extra properties such as vacuum vise, air sliding capacity. These plates are highly recommended to use in flat display industries. We could produce also cylindrical porous ceramics materials, which can applied to precision roller for polymer film precision motion for also electronic industries.

• 한국재료학회지
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• 제26권3호
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• pp.136-142
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• 2016

To study the dispersion factors of silica sol prepared from fumed silica powder, we prepared silica sol under an aqueous system using a batch type bead mill. The dispersion properties of silica sol have a close relationship to dispersion factors such as pH, milling time and speed, the size and amount of zirconia beads, the solid content of fumed silica, and the shape and diameter of the milling impellers. Especially, the silica particles in silica sol were found to show dispersion stability on a pH value above 7, due to the electrostatic repulsion between the particles having a high zeta potential value. The shape and diameter of the impellers installed in the bead mill for the dispersion of fumed silica was very important in reducing the particle size of the aggregated silica. The median particle size ($D_{50}$) of silica sol obtained after milling was also optimized according to the variation of the size and amount of the zirconia beads that were used as the grinding medium, and according to the solid content of fumed silica. The dispersion properties of silica sol were investigated using zeta potential, turbiscan, particle size analyzer, and transmission electron microscopy.

• Journal of the Korean Wood Science and Technology
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• 제51권1호
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• pp.23-37
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• 2023

One type of biomass that has promising potential for bio pellet production is spent coffee grounds (SCGs). However, previous studies have shown that SCGs in bio pellets cause a lot of smoke. Therefore, they need to be mixed with a material that has a higher calorific value to produce better quality pellets. One material that can be used is pine wood because it has a natural resin content that can increase the calorific value. The aim of this study was to examine the quality of bio pellets produced with SCGs and pine wood charcoal at different particle sizes. The charcoal was ground using either a hammer mill (HM) or a ball mill (BM). Pine wood charcoal was mixed with SCGs at ratios of SCGs to pine wood charcoal of 4:6 and 6:4 by weight, respectively, and the adhesive used a tapioca with a composition ratio 5% of the raw material. The bio pellets were produced using a manual pellet press. The quality of the bio pellets was assessed based on Indonesian National Standard (SNI) 8021-2014, and the physical observations include flame length, burning rate, and compressive strength. The average water content, ash content, and calorific value of the bio pellets were in accordance with SNI 8021-2014, but the density and ash content values were below the standard values. The BM variation of bio pellets had a higher compressive strength than the HM variation, and the 4:6 BM variation had the longest burning time compared with 4:6 HM.

• 자원리싸이클링
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• 제33권2호
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• pp.37-45
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• 2024

몰리브덴은 높은 내열성, 내부식성에 의해 다양한 산업에 적용되어, 우리나라의 핵심광물로 선정된 중요한 금속이다. 그러나 최근 몰리브덴 광맥의 저품위화로 인해 생산에 어려움을 겪고 있어, 몰리브덴 선광 공정에 대한 효율 향상이 필요하다. 본 연구에서는 국내 몰리브덴광 선광 공정의 효율 향상을 위한 기초 선광 특성 평가 연구를 수행하였다. 기초 선광 특성은 광물학적 분석, 분쇄일지수, 부유선별 속도 분석으로 평가되었다. 분석 결과, 단체분리가 가능한 몰리브덴광의 입자 크기는 ~100 ㎛였으며, 분쇄 일지수는 14.57 kWh/t로 산출되었다. 또한 부유선별 속도 분석을 통해, 부유선별 단위 공정 각각의 최적 부유선별 시간을 제공함으로써 최적화를 위한 운영 조건을 확립하였다. 마지막으로 본 연구에서 제공한 몰리브덴광 기초 선광 특성 정보는 향후 산업 규모의 몰리브덴 선광 플랜트의 분쇄 및 부유선별 공정을 진단하는 데 활용될 예정이다.