• 한국농공학회지
• /
• 제45권5호
• /
• pp.133-139
• /
• 2003

Dredged soil from sea has much higher water content than liquid limit of clay and even if small loads apply, it will suffer a great settlement. Therefore it is very difficult to perform a consolidation test with general consolidation apparatus because of high water content. In this study Rowe Cell Apparatus consolidation tests have been performed with 1 remolding clay of water content 56% and 4 slurry clays of a water content of 100%, 120%, 133% and 150%. From the test results the consolidation characteristics such as compression index, secondary compression index and consolidation coefficient have been investigated with a variation of water content of dredged soil. The equations to get consolidation constants such as a compression index, a consolidation coefficient have been proposed with the field water content.

• 한국감성과학회:학술대회논문집
• /
• 한국감성과학회 2000년도 춘계 학술대회 및 국제 감성공학 심포지움 논문집 Proceeding of the 2000 Spring Conference of KOSES and International Sensibility Ergonomics Symposium
• /
• pp.99-103
• /
• 2000

There are two approaches in the study of emotion in the physiological psychology. The first is to clarify the brain mechanism of emotion, and the second is to evaluate objectively emotions using physiological responses along with our feeling experience. The method presented here belongs to the second one. Our method is based on the "level-crossing point detection" method. which involves the analysis of frequency fluctuations of EEG and is characterized by estimation of emotionality using coefficients of slopes in the log-power spectra of frequency fluctuation in alpha waves on both the left and right frontal lobe. In this paper we introduce a new theory of estimation on an individual's emotional state by using our non-invasive and easy measurement apparatus.

• 전기학회논문지
• /
• 제56권1호
• /
• pp.222-226
• /
• 2007

We suggest the fluorescence endoscope system that has light source apparatus providing selectable white or excitation light. White light source generates normal color images and is easily switched over to excitation light with the wide spectrum range from 380 nm to 580 nm. 5-ALA is deposited selectively in the abnormal tissue like cancer and causes fluorescence in the red spectrum range when excited by blue spectrum range. In addition, the others of excitation light make the color background image by reflected light to allow accurate orientation and visualization of the abnormal tissue and around. According to clinical studies, the fluorescence intensity contrast that defines the fluorescence intensity of lesion over the fluorescence intensity of around has more than 2 in tumour. Proposed system is useful and objective way in early diagnosis. Furthermore, it can be used in the biopsy for tumour classification at the highest fluorescence intensity point.

• Smart Structures and Systems
• /
• 제4권3호
• /
• pp.279-290
• /
• 2008

The modeling and parameter estimation of a damped one-degree-of-freedom mass-spring system is examined. This paper presents a method for estimating the system parameters (damping coefficients and natural frequency) from measured free-vibration motion of a system that is modeled to include both subcritical viscous damping and kinetic Coulomb friction. The method applies a commercially available least-squares curve-fitting software function to fit the known solution of the equations of motion to the measured response. The method was tested through numerical simulation, and it was applied to experimental data collected from a laboratory mass-spring apparatus. The mass of this apparatus translates on linear bearings, which are the primary source of light inherent damping. Results indicate that the curve-fitting method is effective and accurate for both perfect and noisy measurements from a lightly damped mass-spring system.

• 분석과학
• /
• 제13권3호
• /
• pp.399-402
• /
• 2000

To determine the concentrations of microcystins present in lake water or in tap water using high performance liquid chromatography, it is necessary to concentrate a large volume of water samples (about 20 L) into very small volume (0.1-0.3 mL). Concentration can be conveniently done when disc type solid phase extraction (SPE) apparatus is used. Using this apparatus we have investigated the recovery rates of three kinds of microcystins, RR, YR, LR. The recovery rates were relatively low and the reproducibilities were not good either. It is expected, however, that the appropriate selection of the disc conditioning and eluting solvents and reproducible reconcentration process after SPE will improve both the recovery rates and the reproducibilities.

• Journal of Astronomy and Space Sciences
• /
• 제33권1호
• /
• pp.55-62
• /
• 2016

Heumgyeonggaknu (欽敬閣漏) is powered by a water-hammering-type water wheel. The technique that maintains the constant speed of the water wheel is assumed to be the one used in the Cheonhyeong (天衡) apparatus in Shui Yun Yi Xiang Tai (水運儀象臺) made by the Northern Song (北宋) dynasty in the 11^th century. We investigated the history of the development and characteristics of the Cheonhyeong apparatus, and we analyzed ways to transmit the power of Heumgyeonggaknu. In addition, we carried out a conceptual design to systematically examine the power control system. Based on the conceptual design, we built a model for a water wheel control system that could be used in experiments by drawing a 3D model and a basic design.

• Geomechanics and Engineering
• /
• 제10권1호
• /
• pp.1-19
• /
• 2016

This paper presents the results of an intensive experimental investigation on cyclic behavior of various sands and structural materials interface. Comprehensive measurements of the horizontal displacement and shear stresses developed during testing were performed using an automated constant normal load (CNL) cyclic direct shear test apparatus. Two different particle sizes (0.5 mm-0.25 mm and, 2.0 mm-1.0 mm) of sands having distinct shapes (rounded and angular) were tested in a cyclic direct shear testing apparatus at two vertical stress levels (${\sigma}=50kPa$, and 100 kPa) and two rates of displacement ($R_D=2.0mm/min$, and 0.025 mm/min) against various structural materials (i.e., steel, concrete, and wood). The cyclic direct shear tests performed during this investigation indicate that (i) the shear stresses developed during shearing highly depend on both the shape and size of sand grains; (ii) characteristics of the structural materials are closely related to interface response; and (iii) the rate of displacement is slightly effective on the results.

• 한국분말재료학회지
• /
• 제20권1호
• /
• pp.48-52
• /
• 2013

A study of oxidation kinetic of Fe-36Ni alloy has been investigated using thermogravimetric apparatus (TGA) in an attempt to define the basic mechanism over a range of temperature of 400 to $1000^{\circ}C$ and finally to fabricate its powder. The oxidation rate was increased with increasing temperature and oxidation behavior of the alloy followed a parabolic rate law at elevated temperature. Temperature dependence of the reaction rate was determined with Arrhenius-type equation and activation energy was calculated to be 106.49 kJ/mol. Based on the kinetic data and micro-structure examination, oxidation mechanism was revealed that iron ions and electrons might migrate outward along grain boundaries and oxygen anion diffused inward through a spinel structure, $(Ni,Fe)_3O_4$.

• 한국전기전자재료학회논문지
• /
• 제19권4호
• /
• pp.328-333
• /
• 2006

In this paper, we developed a pressure measurement apparatus with the parallel structure to improve the measurement efficiency of pressure sensors by reducing the measurement time of pressure. The developed system has two parallel positions for loading Silicon pressure sensor and has a dual valve structure. The semiconductor pressure sensors prepared by Copal Electronics were used to confirm the performance of the developed measurement system. Two stage differential amplifier circuit was employed to amplify the weak output signal and the amplified output signal was improved utilizing a low-pass filter. New apparatus shows the measurement time of pressure two times shorter than that of conventional one with the serial structure, while both structures show the similar linear output versus pressure characteristics.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
• /
• pp.700-702
• /
• 2005

The most electrical apparatus should be able to withstand short-time current and peak current during a specified short time until circuit breakers have interrupted fault current. It defines the short-time withstand ability of electric a apparatus to be remain for a time interval under high fault current conditions. It is specified by both dynamic ability and thermal capability. KERI(Korea Electrotechlology Research Institute) recently constructed the new short-time current and low voltage short circuit testing facilities. This paper shows short- circuit calculation of transformer and describes high current measuring system, and evaluate the result of short-time withstand test used in $3{\phi}$ 90MVA short-time current testing facilities.