• Tribology and Lubricants
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• 제9권2호
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• pp.36-48
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• 1993

This study is concerned with the changes (deterioration) of the mechanical properties of used oil in the gasoline engine. The analysed properties of used oil were friction, antiwear, wear debris, load-carrying ability and the formation of surface film. From this study, it was found that the oil used in engine was deteriorated to increase the wear and fricion and decrease the load-carrying ability as the running distance of oil was increased. Also the main cause of deterioration was related to the formation of the protective film on the contact zone. When the film was composed with rich additives (sulfur), this could properly protect contact zone from the increase of wear and friction. But as oil was deteriorated, it could not form such a film and therefore the protective ability of sliding surface diminished.

• 한국공작기계학회논문집
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• 제16권2호
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• pp.106-111
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• 2007

In this research work attempts were made to study the bonding of thermo-plastics with adhesives using solar radiation. In order to study the curing behaviour necessary experiments were conducted under varying conditions of temperature, exposure time and power of solar energy. The cured samples were then studied under the optical microscope before subjecting to tensile testing in order to study their mechanical properties of thermo-plastics. The fracture surfaces were further studied under the Scanning Electron Microscopy(SEM) in order to research the microstructural changes that are taken place during curing. In order to measure the performance of solar energy cured joints the parameters such as; bond strength, surface morphology, the microstructual changes, variation in properties of adhesives bonded joints are compared to that of specimen cured at ambient conditions and specimen cured using microwave techniques.

• 펄프종이기술
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• 제48권2호
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• pp.68-74
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• 2016

Nanofibrillated cellulose (NFC) was prepared from cotton linter after electron beam irradiation to investigate its effects on the manufacturing efficiency of the NFC preparation and the property changes by the treatment. Mechanical device (Super Masscolloider) was used to prepare the NFC and its passing frequency for each NFC preparation was recorded. More electron beam irradiation resulted in less passing frequency. Alpha cellulose content, molecular weight, crystallinity index, and thermal decomposition behavior of each treatment were lowered by electron beam treatment (10 and 100 kGy) and grinding process. NFC films were prepared to investigate their mechanical properties. There were little changes in tensile properties of the NFC films.

• 동아시아식생활학회지
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• 제20권1호
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• pp.69-76
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• 2010

This study was performed to examine the effects of salt addition level on changes in the physicochemical properties and color values of salted shrimp during fermentation. Fresh shrimp were salted with different concentrations (8, 18, 28%) of Chunil salt and fermented at $20^{\circ}C$ for 160 days. In the 8% salted shrimp treatment, volatile basic nitrogen (VBN), amino nitrogen (AN), and trimethylamine (TMA) contents rapidly increased during the fermentation period, while in the 18 and 28% salt groups these increases were reduced throughout the 160 days of fermentation. Thiobarbituric acid (TBA) values increased rapidly for 120 days of fermentation and then decreased. The thiobarbituric acid values of the 18, and 28% salted and fermented shrimp groups were lower than the that of the 8% group. In addition, Hunter's color L, a, and b values decreased as the fermentation period increased.

• KCI Concrete Journal
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• 제14권4호
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• pp.161-169
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• 2002

The mechanical properties of fiber reinforced porous concrete for use as a planting material were investigated in this study. Changes in physical and mechanical properties, subsequent to the addition of carbon fiber and silica fume, were studied. The effects of recycled aggregate were also evaluated. The applicability as planting work concrete material was also assessed. The results showed that there were no remarkable changes in the void and strength characteristics following the increase in proportion of recycled aggregate. Also, the mixture with 10% silica fume was found to be the most effective for strength enforcement. The highest flexural strength was obtained when the carbon fiber was added with $3\%$. It was also noticed that PAN-derived carbon fiber was superior to Pitch-derived ones in view of strength. The evaluation of its usage for vegetation showed that the growth of plants was directly affected by the existence of covering soil, in case of having the similar size of aggregate and void.

• 한국수소및신에너지학회논문집
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• 제5권1호
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• pp.33-39
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• 1994

The changes of hydrogenation properties of $LaNi_5$ by hydrogen charging condition were investigated using the P-C-isotherm curves, DSC(Differential Scanning Calorimetry), GC(Gas Chromatograph), X-ray diffractometer. As a results of static hydrogen charging, the hydrogen storage capacity gradually decreased and the plateau region severly slopped. Most of the degraded properties could be restored by the annealing treatment. The degradation of hydrogen storage capacity was related with the formation of stable hydride, which was not dehydrided at room temperature.

• Journal of Photoscience
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• 제6권4호
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• pp.171-176
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• 1999

The spectral and photophysical properties of trans-1-pyrazinyl-2-(3-quinolinyl)ethylene (trans-3- PyQE) are investigated under various conditions in order to obtain information on ground and excited states. The absorption spectrum of trans-3-PyQE changes slightly with varying degree of solvent polarity ; the. fluorescence spectrum is shifted to the red and becomes broad and structureless as the solvent polarity increases. The fluorescence quantum yield increases with increasing solvent polarity. The fluorescence intensity of trans-3-PyQE decreases as the concentration of methyl iodide increases. The fluorescence spectra of trans-3-PyQE changes markedly upon the variation of the excitation wavelength, presumably due to an equilibrium between conformers originating from the rotation of a quasi-single bond between the quinolinyl group and ethylenic carbon atom. These results indicate that the spectral and photophysical properties of trans-3-PyQE are strongly influenced by solvent, heavy atom, and an equilibrium between conformers

• 한국식품영양학회지
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• 제23권1호
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• pp.114-117
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• 2010

The effects of isolated soy protein(ISP) content on the physicochemical properties of extrudates from rice flour produced by a single-screw extruder were evaluated. The integrity index(II), nitrogen solubility index(NSI), rehydration ratio(RR), and density were measured as indices of the changes of physicochemical properties of rice extrudates. Increased amounts of ISP resulted in increased II but decreased RR and density. There was no change in the NSI value. It was concluded that the addition of ISP to the raw material could be helpful in texturization of rice extrudate.

• 한국식품조리과학회지
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• 제12권3호
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• pp.300-304
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• 1996

증편반죽의 증자과정 중에 일어나는 변화양상을 규명하고자 발효시간을 0에서 10시간까지 달리한 증편제품들을 비교 검토하였다. 발효시간에 따른 증편제 품의 화학적 성질들의 변화양상은 반죽시료의 경우와 유사하였으나 증자과정 중 pH는 약간 증가한 반면에 적정산도, lactic acid, 총 당과 환원당, 가용성 단백질 과 총 유리아미노산은 감소하였고 특히 환원당이 크게 감소하였으며 또한 유리아미노산의 종류별로는 다소 증가 혹은 감소하여 일정한 경향을 보이지 않았다.

• 말소리와 음성과학
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• 제2권4호
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• pp.93-100
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• 2010

The purpose of this study was to compare the acoustic properties of fricatives, /ㅅ, ㅆ/ produced by children with functional articulation disorder and normal children (N=20, aged 6-7). All subjects showed significant differences in both the length of friction intervals and breathing intervals of fricatives according to the changes in the environment presented within each group. However, there is a difference in the extent of variation in length between the two groups. This means that children with functional articulation disorder have greater difficulty in adjusting fricative noises according to changes in the CV VCV environment than normal children.