• Journal of Advanced Marine Engineering and Technology
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• 제25권2호
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• pp.331-337
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• 2001

A numerical simulation of the temperature rise for sliding surface in dry contact is based on Jaegers formula combined with a calculated heat input. A gear tooth temperature analysis was performed. The pressure distribution has the Hertzian pressure distribution on the heat source. The heat partition factor is calculated along ling of action. A Temperature distribution of tooth surface is calculated about before and after profile modification. A Temperature of addendum and deddendum in modified gear have reduced.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2005년도 동계학술연구발표회 및 2차 아시안포럼
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• pp.82-83
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• 2005

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1995년도 추계 학술발표회
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• pp.120-121
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• 1995

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 1995년도 추계 학술발표회
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• pp.119-119
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• 1995

• 농업과학연구
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• 제9권1호
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• pp.269-274
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• 1982

Bulk pasteurization system을 농가(農家)에 보급(普及), 실용(實用) 가능성(可能性)을 검토(檢討)하고 동(同) system을 이용(利用)한 퇴비배지(堆肥培地)의 발효방법(醱酵方法)을 확립(確立)하기 위(爲)한 실험(實驗)을 실시한 결과(結果)는 다음과 같다. 1. 양송이배지(培地)의 후발효과정(後醱酵過程)은 bulk pasteurization system으로 실시(實施)하는 것이 관행방법(慣行方法)보다 우수(優秀)하여 자실체수량(子實體收量)이 높았다. 2. Bulk pasteurization system으로 균배양(菌培養)을 한 결과(結果) 관행방법(慣行方法)보다 균사생장(菌絲生長)이 불량(不良)하고 수량(收量)이 낮았는데 이것은 송풍기(送風機)의 결함(缺陷)과 불완전(不完全)한 작업(作業)에 기인(基因)하였다. 3. 기존(旣存) 양송이재배사(栽培舍)를 개수(改修)한 간이(簡易) bulk pasteurization system은 배지(培地)의 발효(醱酵)가 불량(不良)하여 자실체수량(子實體收量)이 낮고 재배(栽培)의 안정성(安定性)이 적었다. 4. 배지(培地)의 후발효(後醱酵)를 bulk pasteurization 방법(方法)으로 할때 정열도달시간(頂熱到達時間), 후발효시간(後醱酵期間) 및 배지(培地)의 성분변화(成分變化)는 기온(氣溫)의 영향(影響)을 받았으나 관행방법(慣行方法)보다는 현저(顯著)한 안정성(安定性)을 보였다. 5. 시설(施設)이 잘된 bulk pasteurization system으로 후발효(後醱酵)할 때 입상시(入床時) 배지(培地)의 수분함량(水分含量)은 발효(醱酵)에 큰 影響을 미치지는 않았으나 배지(培地)의 성분(成分)에 약간 차이(差異)가 있었다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2001년도 추계학술대회 논문집
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• pp.272-276
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• 2001

Multicomponent $Zr_{41.2}Ti_{13.8}Cu_{12.5}Ni_{10}Be_{22.5}$ bulk matallic glass alloy shows good bulk glass forming ability due to its high resistance to crystallization in the undercooled liquid state.1) In this study, DSC and X-ray diffractometry have been performed to confirm the amorphous structure of the master $Zr_{41.2}Ti_{13.8}Cu_{12.5}Ni_{10}Be_{22.5}$ alloy. To investigate the mechanical properties and deformation behaviors of the bulk metallic $Zr_{41.2}Ti_{13.8}Cu_{12.5}Ni_{10}Be_{22.5}$ alloy, a series of compression tests has been carried out at the temperatures ranging from $351^{\circ}C$ to $461^{\circ}C$ and at the various initial strain rates from $2{\times}10^{-4}s^{-1}\;to\;2{\times}10^{-2}s^{-1}$. There are two types of nominal stress-strain curves. The one shows linear stress-strain relationship meaning fracture at maximum stress, the other shows plastic deformation including steady-state flow. Also DSC analysis for the compressed specimens has been performed to investigate the change of thermal stability and crystallization behavior for the various test conditions.

• 한국환경과학회지
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• 제23권6호
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• pp.1199-1211
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• 2014

The momentum flux and the sensible heat flux were measured with the scintillometers and ultrasonic anemometers at 6 sites of which surface characteristics like roughness length and zero-displacement are different each other. We estimated the momentum flux and the sensible heat flux based on the bulk transfer method with the drag coefficient and the heat transfer coefficient calculated from the temperature and wind speed at two heights. The variation of bulk transfer coefficients showed a remarkable difference depending on the atmospheric stability which is less influenced by the zero-displacement than the roughness length. The estimated sensible heat fluxes were in good agreement with those measured at 3 m, showing 23.7 $Wm^{-2}$ of the root mean square error that is less than 10% of its maximum. Since the estimated momentum flux is not only effected by drag coefficient but also by wind speed square, the determination of wind speed in the bulk transfer method is critical.

• 한국공작기계학회논문집
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• 제16권6호
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• pp.193-200
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• 2007

Micro forming is a suited technology to manufacture very small metallic parts(several $mm{\sim}{\mu}m$). Al5083 superplastic alloy with very small grains has a great advantage in achieving micro deformation under low stress due to its relatively low strength at a specific high temperature range. Micro forming of $Zr_{62}Cu_{17}Ni_{13}Al_8$ bulk Metallic glass(BMG) as a candidate material for this developing process are feasible at a relatively low stress in the supercooled liquid state without any crystallization during hot deformation. In this study, the micro formability of Al5083 superplastic alloy and bulk metallic glass, $Zr_{62}Cu_{17}Ni_{13}Al_8$, was investigated with the specially designed micro vibration forming system using pyramid-shape, V-shape and U-shape micro die pattern. With these dies, micro vibration forming was conducted by varying the applied load, time. Micro formability was estimated by comparing the hight of formed shape using non-contact surface profiler system. The vibration load effect to metal flow in the micro die and improve the micro formability of Al5083 superplastic alloy and $Zr_{62}Cu_{17}Ni_{13}Al_8$ bulk Metallic glass(BMG).

• Preventive Nutrition and Food Science
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• 제17권3호
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• pp.203-209
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• 2012

The effects of variable moisture content, screw speed and barrel temperature on the physicochemical properties of red ginseng powder extrudates were investigated. The raw red ginseng powders were processed in a co-rotating intermeshing twin-screw extruder. Primary extrusion variables were feed moisture content (20 and 30%), screw speed (200 and 250 rpm) and barrel temperature (115 and $130^{\circ}C$). Extruded red ginseng showed higher crude saponin contents (6.72~7.18%) than raw red ginseng (5.50%). Tested extrusion conditions did not significantly affect the crude saponin content of extrudates. Increased feed moisture content resulted in increased bulk density, specific length, water absorption index (WAI), breaking strength, elastic modulus and crude protein content and decreased water solubility index (WSI) and expansion (p<0.05). Increased barrel temperature resulted in increased total sugar content, but decreased reducing sugar content in the extrudate (p<0.05). Furthermore, increased barrel temperature resulted in increased amino acid content and specific length and decreased expansion and bulk density of extrudates only at a higher feed moisture content. The physicochemical properties of extrudates were mainly dependent on the feed moisture content and barrel temperature, whereas the screw speed showed a lesser effect. These results will be used to help define optimized process conditions for controlling and predicting qualities and characteristics of extruded red ginseng.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 유기절연재료 전자세라믹 방전플라즈마 일렉트렛트 및 응용기술
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• pp.88-92
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• 2002

$Ba(Zn_{0.8}Co_{0.2})_{1/3}Ta_{2/3}O_3$ [BZCT(80/20)] ceramics were prepared by the conventional mixed oxide method. The ceramics were sintered at the temperature of $1450{\sim}1550^{\circ}C$ for 5hr. in air. The structural properties of BZCT(80/20) ceramics were investigated as a function of sintering temperature. The BZCT(80/20) ceramics sintered at $1550^{\circ}C$ showed a polycrystalline complex perovskite structure without second phases and any unreacted materials. Increasing the sintering temperature, the bulk density and ordering were increased. The bulk density of the BZCT(80/20) ceramics sintered at $1550^{\circ}C$ was 7.50[$g/cm^2$]. Increasing the sintering temperature, the average grain size were increased and pore were decreased.