• Korean Journal of Materials Research
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• v.2 no.6
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• pp.461-467
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• 1992

A fabrication process for SiC whisker preform reinforced AC4A Al composites is being developed. The Al alloy used as the matrix in this study is AC4A. SiC whisker preform made by Tokai Carbon Co. Ltd. Shizuoka, Japan were used. These consisted of $\beta$-type single crystals 0.1 ~ 10${\mu}$m in diameter and 20~10${\mu}$m in length. The most adequate fabrication condition was that whisker preform was preheated up to 750~80$0^{\circ}C$, set into a mould preheated to ~40$0^{\circ}C$, molten Al alloy heated to ~80$0^{\circ}C$ and applied pressure 75MPa. And Si$C_w$reinforced AC4A composite was advanced above twice than AC4AI/M. Also it was not large effect by pressure at Si$C_w$ 20v/o.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.255-255
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• 2017

Sesame has been consumed for centuries as flavoring ingredient in eastern Asian countries, especially Korea. Sesame seeds have been used as health food for traditional medicine to prevent disease in Asian countries for several thousand years. Sesame seed has higher oil content (around 50%) than most of the known oilseeds. Sesame oil is rich in monounsaturated and polyunsaturated fatty acids. Extraction of sesame has developed significantly over the years. The mechanical method was an early means of separation which was physical pressure to squeeze the oil out. Nowadays, solvent extraction becomes the commonly used commercial technique to recover oil from oilseeds. In this study, we investigated extraction efficiency and quality of oil affected by cultivars and extraction methods of sesame seed. Different variables were investigated; roasting temperature ($170{\sim}220^{\circ}C$), extraction methods (solvent and physical pressure), forced ventilation system and cultivars. The Contents of B(a)P in sesame oil after roasting at $170{\sim}220^{\circ}C$ were 0.30~2.53 ppm. When we introduced forced ventilation system during roasting, B(a)P Contents were decreased up to 36%. The Oil extraction efficiency on sesame seed was statistically depending on the cultivars and extraction methods. The oil extraction yields of solvent and physical pressure extraction were 56.3% and 44.6%, respectively. Many of sesame cultivars and genetic resources are linolenic acid content of less than 0.5%. The results supported that we have developed a safe and high quality sesame oil processing methods for small and medium-sized companies.

• International Journal of Precision Engineering and Manufacturing
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• v.8 no.2
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• pp.44-48
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• 2007

In recent years, the size of plane substrates and semiconductor wafers has increased. As conventional contact transportation systems composed of, for example, carrier rollers, belt conveyers, and robot hands carry these longer and wider substrates, the increased weight results in increased potential for fracture. A noncontact transportation system is required to solve this problem. We propose a new noncontact transportation system combining acoustic viscous and aerostatic forces to provide damage-free transport. In this system, substrates are supported by aerostatic force and transported by acoustic viscous streaming induced by traveling wave deformation of a disk-type stator. A ring-type piezoelectric transducer bonded on the stator excites vibration. A stator with a high Q piezoelectric transducer can generate traveling vibrations with amplitude of $3.2{\mu}m$. Prior to constructing a carrying road for substrates, we clarified the basic properties of this technique and stator vibration characteristics experimentally. We constructed the experimental equipment using a rotational disk with a 95-mm diameter. Electric power was 70 W at an input voltage of 200 Vpp. A rotational torque of $8.5\times10^{-5}Nm$ was obtained when clearance between the stator and disk was $120{\mu}m$. Finally, we constructed a noncontact transport apparatus for polycrystalline silicon wafers $(150(W)\times150(L)\times0.3(t))$, producing a carrying speed of 59.2 mm/s at a clearance of 0.3 mm between the stator and wafer. The carrying force when four stators acted on the wafer was $2\times10^{-3}N$. Thus, the new noncontact transportation system was demonstrated to be effective.

• The Korean Journal of Physiology
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• v.23 no.1
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• pp.151-167
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• 1989

The present study was undertaken to investigate modification in electrophysiological characteristics of cat dorsal horn cells resulting from carrageenin-induced inflammation. The followings were studied; 1) the time-course of changes in responses of the WDR (wide dynamic range) cell 1-3h after subcutaneous injection of carrageenin in its receptive field; 2) the responses of the same dorsal hern cells before and after induction of inflammation; 3) the effect of inflammation on the responsiveness of dorsal horn neurons to algogens (bradykinin & potassium); and 4) the effect of inflammation on the activity of WDR cell following administration of indomethacin and clonidine. Though responses of WDR neuron were increased dramatically during first 1h, the maximal enhancement was observed 3h after induction of inflammation especially by repetitive light tactile stimulus. Following carrageenin injection the majority of WDR neurons (10/15 units) showed enhanced responses to all the mechanical stimuli while in 3 cases responsiveness were intensified during activation by one tactile stimulus (brush or pressure). One cell was unaffected by inflammation and in another case the response was enhanced only to noxious stimulus. Five of 9 cells that could initially be driven by noxious stimulus were activated more strongly by same stimulus and even by tactile stimulus (pressure) following inflammation. In 2 cases neurons were sensitized only to noxious stimulus whereas in another 2 cells that did not show enhanced responses to noxious stimulus responses to light tactile stimulus (pressure) appeared after inflammation. Of 16 LT cells tested 6 responded to squeeze while 4 showed the characteristics of WDR cell following inflammation. No modification in responsiveness was recognized in 3 cells whereas response to only brush was enhanced in another 3 neurons. Following carrageenin injection responses of LT cell to bradykinin or $K^{+}$ were not altered whereas those of WOR neurons to bradykinin or $K^{+}$ were suppressed in 22.2% and 33.3% of cases, respectively. In two of 8 activity of HT cells were inhibited by bradykinin while in five of 8 responsiveness to $K^{+}$ were rather enhanced by inflammation. In the rest inflammation was ineffective. In inflammation-induced animal the receptive field of LT cell was not changed whereas those of WDR cell and HT cell were tremendously expanded. The enhanced responses of WDR neurons to mechanical stimuli resulted from inflammation were suppressed by intravenously injected indomethacin and clonidine suggesting that postaglandin is involved in inflammation-induced sensitization of these cells. The involvement of peripheral and central mechanisms in the modification in responsiveness of dorsal horn cells in the carrageenin-induced inflammation was discussed.

• Journal of the Korean Society for Nondestructive Testing
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• v.16 no.4
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• pp.225-233
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• 1997

This study is performed to establish a non-destructive evaluation method for metal matrix composite using ultrasonic technique. The specimen is made of SiC/AC8A metal matrix composite by squeeze-casting method. Three kinds or reinforced particles are prepared as 4.86, 8.09 and $11.44{\mu}m$ to investigate the effect of size on the mechanical and ultrasonic properties of metal matrix composite. In addition, four different volume fractions (14, 22.5, 27.5, 35%) of reinforced particles are prepared per each size to examine the effect of volume fraction on the ultrasonic properties. From this specimen, the availability and precision of measurement of Young's modulus are examined and the evaluation method for microstructure of metar matrix composite using the speed of sound and attenuation factor is also reviewed. The results show that the Young's modulus measured by ultrasonic method is as effective as that measured by mechanical method. It is also known that the size and volume fraction of reinforced fiber are precisely evaluated using the speed of sound and attenuation factor.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.135-139
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• 2017

The main reason for heat accidents occurring at the after stern tube bearing (STB) is excessive local pressure caused by the deflection of the propulsion shaft due to propeller loads. The probability of a heat accident is increased by the low flexibility of the shaft system in very large crude oil carriers (VLCCs) as the engine power and shaft diameter increase and the distance decreases between the forward and after STBs. This study proposed shaft system with only an after STB and no forward STB for a flexibility acquisition method for a VLCC shaft system under hull deformation. A Hertzian contact condition was applied, which assumes a half-elliptical pressure distribution along the contact width for the calculation of the local squeeze pressure. The propeller loads, heat effect, and hull deflection under engine operating conditions are also considered. The results show that the required design criteria were satisfied by building a partial slope at the white metal, which is the material at the axial contact side in the after STB. This system could reduce building cost by simplification of the shaft system.

• Journal of Haehwa Medicine
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• v.12 no.1
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• pp.103-121
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• 2003

Human being can't live without nature, then the changes of nature affect human body. It means that human body has corresponding changes to the KI(vital energy) of nature. There is a stream of changes in human body which circulate mysteriously and punctually by the laws of nature. If this stream of changes fits into human's life style, it would be most effective. It has a certain mode continuously. So if a person has a habit fitting into it, he will get the healthiest body. Then the researcher tries to explain the changes in human body by the time, mainly focused on within 24 hours. it is showing not only the oriental view, but also the western's. The researcher can find the coincidence as followings. At In-Si(3-5 am), the body function and the body temperature get to the bottom, therefore it's good for him to wake up and to run the vital energy. At Sa-Si(9-11 am), the patience on pain anxiety and the psychic concentration get to the top, he'd better start the work. At O-Si(11am-1pm), the heart energy has a vital move, then the blood concentration of Hb(hemoglobin) gets to the top. At Mi-Si(1-3 pm), the muscle strength, the squeeze, and the breathing rate increase. The reflex nerve sensitivity gets to the top. Creativity, observation, and working efficiency go high, so it's time to work hard. At Hae-Si(9pm-1am), the body function falls, sleeping is needed. At Chuck-Si(1-3 am), the cell spontaneity gets to the top, immune lymphocyte moves actively, and the blood concentration of growth hormone gets to the top. These are liver's work. In west, there has been active studies on how to reduce the side effect by using a person's bio-rhythm based on the 'time treatment', and how to reorganize the bio-rhythm by using the machine and the age resistance based on the 'bio-watch'. Though the 'time treatment' means something, the artificial resistance on bio-rhythm seems to give bad effects to human body. If a person lives by regimen of oriental medicine, he will maintain the healthiest body. Regimen is that human body follows the laws of nature, and moves its mysterious, Punctual and periodical changes.

• Horticultural Science & Technology
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• v.28 no.5
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• pp.790-795
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• 2010

This experiment was conducted to clarify the effects of cycloheximide and holding solution on vase life of cut 'Blue Magic' iris. The vase life of iris flowers held in 3% sucrose (S) + $100mg{\cdot}L^{-1}$ hydroxy quinoline sulfate (HQS) + $50mg{\cdot}L^{-1}$ $AgNO_3$ + $100mg{\cdot}L^{-1}$ Benzylaminopurine (BA), 3% S + $100mg{\cdot}L^{-1}$ HQS + $10{\mu}M$ cycloheximide (CHI), or 3% S + $100mg{\cdot}L^{-1}$ HQS + $50{\mu}M$ CHI were much longer than those held in distilled water. Squeeze stem phenomenon that showed at a holding solution containing $200mg{\cdot}L^{-1}$ HQS disappeared at a holding solution containing $100mg{\cdot}L^{-1}$ HQS. The holding solution containing 3% S + $100mg{\cdot}L^{-1}$ HQS + $50mg{\cdot}L^{-1}$ $AgNO_3$ + $100mg{\cdot}L^{-1}$ BA extended the most effective treatments on vase life, fresh weight, water balance, and flowering of cut iris flowers. However, the holding solution containing 3% S + $100mg{\cdot}L^{-1}$ HQS + $10{\mu}M$ CHI and 3% S + $100mg{\cdot}L^{-1}$ HQS + $50{\mu}M$ CHI was not effective in solution uptake or transpiration, but did result in high water balance. Iris flowers treated with CHI at the half-open flower stage showed increases in ornamental value, such as full flower opening and extended vase life. To improve flower quality and prolonging vase life of cut iris flowers, a holding solution containing $50{\mu}M$ CHI can be used continuously from the half-open stage.