• 대한설비공학회지:설비저널
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• 제3권3호
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• pp.185-190
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• 1974

Floor panel heating system is popular in Korea as dwelling house heating system. There are two methods for keeping floor surface warm. One method is delivering warm air under the floor such as Roman Hypocaust and Korean traditional Ondol. The other method is imbedding hot water pipes into the concrete floor slab. This paper gives basic equations for steady and transient solutions of heat conduction from hurried pipes. For steady-state solution, fin Efficiency Method and Sink and Source Method were introduced. Sink and Source Method is applied to transient state and basic solution is given in the form of Exponential Integral Function. Numerical solutions can be solved easily by digital computer from these equations.

• 한국식품영양과학회지
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• 제20권6호
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• pp.559-564
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• 1991

동치미의 저장성 향상효과를 보기 위하여 동치미 제조시와 발효시 열처리 및 염 첨가 등을 같이 행하여 >$25^{\circ}C$에서 발효시키면서 이들이 동치미의 pH, 산도, 텍스쳐, 환원당 및 관능적 품질 변화에 미치는 영향을 측정하였다. 그 결과 열처리와 무기산염 및 인산염을 같이 처리한 방법 B 및 C 처리구가 대조구에 비해 약 2~2.5배의 저장 연장 효과를 보였으며 총산도에서는 열처리 및 KCI, $CaCl_2 첨가를 같이한 방법 A구가 가장 낮은 함량을 나타내었다. 텍스쳐에서는 대체로 대조구에 비해 처리구의 견고성이 높았으며 환원당은 열수담금을 했던 방법 A, B, C는 담금초기부터 환원당의 농도가 높았으나 발효가 진행되면서 감소하여 대조구와 반대현상을 보여주었다. 한편 동치미의 관능적 평가에서는 처리구의 품질이 대조구보다 더 신선하여 같은 발효일에서 생무우내와 생무우맛은 많은 반면 신내와 신 맛은 적은 것으로 나타났다.

• 제어로봇시스템학회논문지
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• 제22권8호
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• pp.627-632
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• 2016

In this paper, we propose a new vision-based defect inspection system for the surface of hot slabs. To minimize the influence of self-emission from slab surfaces with high temperature, an optic method based on blue LED light and a blue pass filter is proposed. Because the slab surface is partially covered with scales, which are unavoidable oxidized substances caused during manufacturing, it is difficult to distinguish between vertical cracks and scale. In order to resolve this problem and to improve the detection performance, the use of a Gabor filter and dynamic programming are proposed. Finally, the effectiveness of the proposed method is shown by means of experiments conducted on images of hot slabs that were obtained from an actual slab production line.

• 대한기계학회논문집
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• 제16권8호
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• pp.1451-1457
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• 1992

본 연구에서는 작업롤의 온도분포를 정상 상태에서 롤의 길이 방향만을 고려 한 경우에 대하여 구한 다음 Fouries 급수로 전개하여 이 온도분포에 따른 작업롤의 축대칭 3차원 열-탄성문제를 해석함으로서 롤의 크라운 양과 열응력을 구하여 이 결과 를 유한요소법에 의한 결과와 비교 검토 하였다.

• 소성∙가공
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• 제32권2호
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• pp.81-86
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• 2023

The hot stamping process is widely used for high strength of vehicle parts, with heating 900 ℃ or higher in a furnace and in-die quenching to achieve strength above 1.5 GPa of the quenchable boron alloyed steel 22MnB5. First of all, the hot stamping process consisted of heating, forming, quenching and trimming. In the trimming process case, the laser method has been conventionally adopted. For laser trimming process, it has the problems pertaining to low productivity and high cost while the hot stamping process, accordingly the trimming process need to investigate the research for alternative method. In order to overcome these issues, many research groups have studied the mechanical trim solution on the hot stamped parts at high temperature. In this study, the mechanical piercing was performed during the hot stamping process at the high temperature for overcome the disadvantages of laser cutting. Also, the process parameters such as piercing time after die closing, clearances of between die and punch were controlled for obtaining the reasonable shear characteristics.

• 한국세라믹학회지
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• 제14권3호
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• pp.163-168
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• 1977

As a wet chemical drying process "hot petroleum drying method" was applied and developed for preparing uniformly fine oxide powder with high purity and sinterreactivity. Using this method solution of sulfates was dried in hot petroleum bath (~17$0^{\circ}C$) to sulfate powder from which corresponding mullite doped by Fe3+ ion was formed. Particle size, shape, decomposition by heat, and phase identification of sulfate andoxide powders determined by DTA, TGA, X-ray diffraction, analysis and electron microscopy: sulfate powder prepared by this drying method is an intimate mixture of the amorphous form of uniformly and finely distributed spherical particles (0.05-0.1$\mu$). Mullitization with the sulfate powder occurs at 110$0^{\circ}C$ in air. The morphology of mullite particle made by firing the sulfate powder at 135$0^{\circ}C$ in oxygen atmosphere is granular of 0.1-0.3$\mu$ in size. This drying process proved to be a very effective method for preparing fine, homogeneous, and highly sinterreactive multicomponent oxide powder without conventional ceramic process of mixing, milling, and granulating. This process can be also applied for preparing electronic ceramic materials which are requisite for high purity and homogeneity.mogeneity.

• 한국세라믹학회지
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• 제35권10호
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• pp.1078-1084
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• 1998

금속 질산염과 urea를 사용하여 연소합성법에 의해 LaCrO3 분말을 제조하고, 용액의 pH를 HNO3와 NH4OH로 조절한 후, 용매의 가열방법에 따른 연소 생성물인 LaCrO3의 형상을 고찰하였다. 연소생성물의 수율은 용액의 pH에 의해 크게 좌우되었다. 용액의 pH가 0.7~4 사이에서는 90% 이상의 수율이 얻어졌으나, 5 이상 또는 0.5 이하의 pH에서는 수율이 크게 감소하였다. 한편, 연소생성물의 형상은 용액의 pH에 무관하였고 용액의 가열방법에 좌우되었다. 용액을 저항가열법으로 가열하여 연소반응시킨 경우의 분말은 미세한 일차입자들이 2차원적으로 연결된 응집체를 형성하고 있었으나, 마이크로파를 인가하여 가열한 경우에는 용액의 pH에 관계없이 미세한 LaCrO3 분말이 얻어졌다. BET 분석 결과, 마이크로파 가열에 의해 얻어진 입자의 비표면적은 25~32m2/g으로 저항가열법으로 가열한 경우의 10-14m2/g에 비해 더 큰 값을 보였다. 이러한 결과는 마이크로파에 의한 연소반응물의 균일한 가열이 연소생성물의 2차원적인 강항 응집체 형성을 억제할 수 있음을 보여 주었다.

• Fisheries and Aquatic Sciences
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• 제6권4호
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• pp.172-179
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• 2003

The safety of pufferfish (Lagocephalus gloveri) liver oil and the contents of some nutritional components were examined to obtain important information on their use as high valued functional foods. Pufferfish liver oil was extracted by the hot-water method using $1\%$ NaOH solution to remove toxic compounds, and then purified using a general purifying method of fish oil. Any extraordinary clinical symptoms were not observed from all groups administrated with pufferfish liver oil throughout the test period. None of the rats died when administrated the highest concentration of 10 mL/kg of the pufferfish liver oil. Vitamin A content was 114.2 ppm, as a retinal equivalent in the oil extracted using hot-water, but the content was higher (169.3 ppm) in oil extracted using n-hexane. Vitamin D and E were not detected in ppm in oil extracted using hot-water. Vitamin D in the pufferfish liver oil extracted using n-hexane was also undetected, but vitamin E was at 32.5 ppm. Among the 18 minerals detected, the sodium content was the highest at 253.5 ppm, followed by 13.9 ppm ofpotassium, 1.5 ppm of calcium, 0.2 ppm of magnesium, and other trace minerals. The contents of EPA and DHA were $0.8\%\;and\;14.8\%$, respectively, in the pufferfish liver oil extracted using hot-water. Considering these results, there is potential that pufferfish liver oil could be used as a functional food.

• 대한기계학회논문집B
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• 제37권12호
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• pp.1147-1152
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• 2013

본 논문에서는 절연된 열선을 이용한 비정상열선법에서 열선의 절연코팅이 선형구간의 초기시점에 미치는 영향을 살펴보기 위하여 이론적인 연구를 수행해 보았다. 이를 위해, 절연된 열선의 온도상승에 관한 해석적 해에서 선형구간의 초기시점에 영향을 미치는 중요한 인자들을 파악해 보았으며, 이러한 인자들의 영향이 무시할 만큼 작아지는 임계시간(critical time)에 대한 연구를 수행해 보았다. 이론적인 연구 결과, 열선의 반경 및 코팅의 두께가 작을수록 절연코팅의 영향이 빠르게 감소하였고, 또한 절연물질의 열전도도가 크고 열확산계수가 작을수록 절연코팅의 영향이 빠르게 감소함을 알 수 있었다. 본 연구의 결과는 절연된 열선을 이용한 비정상열선법에서, 선형구간의 초기시점을 결정하는데 도움이 될 것으로 사료된다.

• 한국잠사곤충학회지
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• 제43권1호
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• pp.37-40
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• 2001

This study was carried out to investigate the optimum condition for silk sericin collection from degumming solution using some aluminium salts with various treatment conditions and examine the thermal properties of silk sericin collected from degumming solution. Silk sericin was precipitated by treatment of aluminium metal compound from degumming solution. The best optimum collecting conditions of silk sericin from degumming solution are the concentration of 2 $m\ell$/l of polyaluminium chloride (PAC), pH range of 5~7 and room temperature. The reduction of water pollution was evaluated by decreasing the chemical oxygen demand (COD) and nitrate ion (NO$_3$￣). Thermal stability of silk sericin collected from degumming solution was a little lower than that of hot water.