• Applied Biological Chemistry
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• v.37 no.2
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• pp.94-99
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• 1994

Bran structure and water uptake rate for brown rices of thirteen japonica and twelve Tongil cultivars were investigated. The japonica type was shorter in length and had lower value in the ratio of length to width than Tongil one. No differences were observed in width and weight between the two types. The number of aleurone layer and the thickness of bran layer were higher in dorsal side than in ventral side in all rice cultivars. The structure in ventral side was similar but the number of aleurone layer in dosal side was higher in japonica samples. There were no significant differences in water uptake rates showed no correlation with the bran structure.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.4
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• pp.66-74
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• 2013

In this study, corrosion potential ($E_{corr}$), corrosion rate, and polarization resistance were measured aimed at inorganic inhibitors (passive film type) and organic inhibitors (absorption type). The experiment was conducted using potentiostat for the variable molar ratio and chloride ion concentration of the components of inhibitors in an aqueous solution of saturated calcium hydroxide targeting corrosion. As a result, it was possible to ensure an anticorrosive performance of at least a 1.2 molar ratio of inorganic inhibitors. Also, the organic inhibitors ensured the prevention of the anticorrosive performance of at least about a 0.3 molar ratio. It also showed the tendency that between polarization resistance and corrosion rate, Ecorr and corrosion rate is inversely proportional to the linear. Conversely, the tendency between polarization resistance and Ecorr is proportional to the linear. Also, a distinct difference in organic and inorganic inhibitors' relationship to Ecorr, corrosion rate, and polarization resistance was not shown.

• Journal of Advanced Navigation Technology
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• v.23 no.3
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• pp.245-250
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• 2019

Inertial navigation system has navigation errors because of the error of inertial measurement unit (IMU) and misalignment over time. In order to solve this problem, aided navigation system is performed using global navigation satellite system (GNSS), speedometer, etc. The inertial navigation system equipped with underwater vehicle mainly uses speedometer and performed aided navigation because satellite signals do not pass through underwater. There are DVL, EM-Log, and RPM in the speedometer, and the sensors are applied according to the system environment. This paper describes velocity aided navigation using RPM of inertial navigation system operating in high speed and deep water environment. In addition, we proposes an algorithm to compensate the limit of RPM with straight direction and the current velocity error. There are results of monte-calo simulation to prove performance of the proposed algorithm.

• Progress in Medical Physics
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• v.5 no.1
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• pp.25-39
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• 1994

To measure the velocity of heart wall and local flow transctaneously in blood vessels, we have developed a single channel 3.1 MHz pulsed ultrasonic Doppler velocity meter. Ultrasound pluse width and repetition frequency (PRF) used in the velocity meter is 1 ${\mu}$sec 6kHz reapectively, and the Doppler shift of the backscattered echo signal is sensed in a phase detector by coherent demodulation method. From the output of the phase detector, the Doppler signal corresponding to the mean velocity of acoustic wave scatterers over a small region is obtained by using a range gate, sample holder and band-pass filter. Mean frequency of Doppler signal is estimated by zero-crossing counter and the instantaneous velocity of scatters is displayed as a function of time. It is possible to estimate velocity profile, volume flow and flow acceleration of vessels in man if the number of channels and range resolution in increased.

• Proceedings of the Optical Society of Korea Conference
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• 1989.02a
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• pp.134-139
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• 1989

레이저 도플러 효과를 써서 유체 또는 작은 입자의 속도를 잴수 있는 레이저 도플러 속도측정 장치를 만들었다. 광학계는 레이저 광속을 두 갈래로 나누어 다시 마주치게 하여 두 광속이 겹치는 곳에, 평행한 삼차원 간섭무늬가 생기도록 꾸몄다. 분무기로 작은 물방울을 만들어 두 광속이 겹치는 곳을 지나게 했더니 도플러 신호를 얻을 수 있었다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.95-95
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• 2003

특정한 마찰 또는 윤활조건 하에서 변형율 속도가 마찰인자에 미치는 영향을 관찰하기 위하여, 약 1$\times$$10^{-3}$/sec, 1$\times$$10^{-2}$/sec, 1$\times$$10^{-1}$/sec에 해당되는 3종류의 변형율 속도에서 평활금형, 흑연계윤활제 및 2황화 몰리브덴계 윤활제에 대한 마찰인자를 상온에서 각각 측정하였다. 측정방법으로서는 외경, 내경 및 높이 비가 6 : 3 : 2인 Al 6061 연주재 ring시편을 공칭변형율 65%까지 약 10% 씩 단속적으로 압축한 후 재윤활 하여주는 단속적 상온 압축시험 방법을 적용하였다. 측정결과, 변형율 속도가 증가함에 따라 윤활제를 사용하지 않은 평활금형에서의 마찰인자는 0.25에서 0.31로 증가, 흑연계 윤활제 적용시에는 0.23에서 0.15로 감소하는 경향을 각각 나타내었고, 2황화 몰리브덴계 윤활제 적용시에는 각각의 변형속도에서 측정된 인자는 0.09-0.10 범위 내로써 마찰인자에 미치는 변형율속도 영향이 아주 미미함을 보여주었다. 본 연구 결과에서는 이 측정결과로부터 각각의 변형속도에서 Al 6061 연주재의 원통형 압축시편으로부터 구한 압축측정응력으로부터 상온유동응력을 구하여 상호 비교하고자 하였다.

• Journal of the KSME
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• v.33 no.9
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• pp.793-802
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• 1993

이 글에서는 부 온도저항계수를 갖는 탄소파이버를 열선으로 이용하고 이를 구동한는 증폭회로의 구성에 관한 연구, 3차원 속도측정용 열선프로브의 접지단자를 3개의 열선이 공통으로 사용하는 공통접지 삼축 열선프로브와 유속계의 특성에 대해 고찰한다. 또한 과열비가 다른 두 개의 저 온도형 열선 유속계를 이용하여 유동장의 온도와 속도를 동시에 측정한는 방법과 임의 형태의 유체온도정보를 이용한 열선유속계의 일반적인 온도보상방법에 관하여 논의하여 열선유속계의 원리와 그 응용 등을 간단히 설명함으로써 관심 있는 분들의 이해를 돕고자 한다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.16 no.2
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• pp.69-74
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• 1987

The effects of soaking temperature on hydration and cooking rates of Chunmabyeo(Japonica) and Kayabyeo(J/Indica) rice were investigated. Water uptake and volume increase rates of milled rice were increased as a function of soaking temperature$(4^{\circ}C{\sim}30^{\circ}C)$. The rate of volume increase of milled rice was greater than that of weight increase, which was more pronounced at low soaking temperature. The soaking of milled rice prior to cooking had a definite effect on the degree of gelatinization. The soaked milled rice was more easily gelatinized than unseated one. The water uptake rate, volume increase rate, degree of gelatinization and cooking rate of milled rice were faster in Kayabyeo than Chunmabyeo.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.813-816
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• 2008

Polycarboxylate-type superplasticizer is widely used for producing self-compacting and high-strength concrete and improving concrete durability. This paper discusses the influence of molecular structure of polycarboxylate-type superplasticizer on the fluidity and the rate of heat liberation of ordinary Portland cement paste. The fluidity of cement paste was increased by addition of polycarboxylate-type superplasticizer. The arrival time up to the maximum rate of heat liberation was increased by addition of polycarboxylate-type superplasticizer. The fluidity and the arrival time up to the maximum rate of heat liberation were more influenced by addition of polycarboxylate-type superplasticizer having shorter grafted chain than that having longer grafted chain.

• Journal of Korea Foundry Society
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• v.30 no.5
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• pp.167-173
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• 2010

벌크 비정질 합금의 특성상 점도가 높고, 냉각속도가 빨라 냉각되는 합금의 온도를 직접 측정하는 것은 곤란하므로, 측정에 의하여 냉각속도를 구하는 것은 매우 어렵다. 본 연구에서는 합금의 온도를 직접 측정하는 대신 금형의 온도를 측정하고, 측정된 금형의 온도를 상용 열해석 프로그램을 이용한3차원 계산 결과와 비교, 보정하는 역문제 기법을 사용하여 Cu계와 Zr계 벌크 비정질합금의 냉각속도를 예측하였다. 예측된 냉각속도는 금형온도와 시편의 두께에 따라Cu계의 경우는 284~300 K/s, Zr계는 279~289 K/s로, 초기 금형온도의 영향은 크지 않은 것으로 나타났다. 전산모사 결과와 달리 금형을 수냉한 쪽보다 가열한 쪽의 응고중 냉각속도가 빨라 조직이 더 미세한 것으로 나타났는데, 이는 응고중 금형과 주물간에 에어갭의 형성으로 열전달을 방해 받은 영향으로 사료된다.