• Journal of the Korean Home Economics Association
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• v.29 no.3
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• pp.61-69
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• 1991

The relationships between nutrients intake, physical activity and bone mineral density were investigated in 19 elderly men aged 71-80 years. A trained nutritionist interviewed usual dietary intake and daily activity with a questionnaire, and bone mineral density was measured at the lumbar spine and three regions of the proximal femur (femur neck, Ward's triangle and trochanter) with a Luna DP3 dual photon absorptiometry. The correlations between dietary calcium intake and bone mineral density at the lumbar spine and trochanteric region were significant at P<0.05 and P<0.01 level respectively. the significant correlations were also found between vitamin A(P<0.005), riboflavin(P<0.01), and ascorbic acid(P<0.05) intake and bone mineral density at these sites. Higher physical activity was associated with greater bone mineral density of four sites, but this was not significant. But there were significant relationships between total energy expenditure and bone mineral density of the lumbar spine(P<0.01), femur neck (P<0.05) and Ward's triangle(P<0.05). In this study the results revealed that bone mineral density of the lumbar spine and trochanteric region were associated with dietary calcium intake. And bone mineral density of the femur neck and Ward's triangle were related to physical activity but not to nutrients intake. In conclusion, dietary calcium intake seems to be a important factor for greater bone mineral density. Further evidence will be needed that physical activity protects against bone fracture and osteoporosis in the edlerly.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.8 s.173
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• pp.27-33
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• 2005

Polishing pads play an important role in chemical mechanical polishing(CMP) which has recently been recognized at the most effective method to achieve global planarization. In this paper, we have investigated CMP characteristics as a change of groove density of polishing pads. The parameter $(K_n)$ is proposed to estimate groove density of pad. The $K_n$ is defined as groove area divided by pitch area. As the groove density value increased, removal rate increased to some point and then gradually saturated in case of increasing the groove density excessively. In addition Within wafer non-uniformity(WIWNU) worse as groove density increased excessively, although WIWNU improved as groove density increased. Also the uniformity of temperature of pad surface decreased as the groove density increased. It was because that the cooling effect increased as groove density increased. In other words, increasing the groove density which means the apparent contact area of pad has influence on amount of discharge of slurry during polishing process.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.605-609
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• 2001

Low density ceramic supporter was prepared by using fly ash as a starting material for the application to the biological aerated filter (BAF) system, and the effect of additives and sintering atmosphere on the apparent and bulk density of the carrier was examined. Borax, Na$_2$O and glass powders were added to produce liquid phase. The density of the supporter decreased as the amount of borax increased. The bulk density of 0.79 g/㎤ and the apparent density of 1.10 g/㎤ were obtained when the fly ash with 15% of borax was sintered at 116$0^{\circ}C$ for 15 minutes. The density also decreased as the plate glass powders past through 22${\mu}{\textrm}{m}$ size were mixed. When the fly ash with 12% of grass powder was sintered at 128$0^{\circ}C$ for 10 minutes, the bulk and apparent density were 0.90g/㎤ and 1.00 g/㎤, respectively. Apparent density of 1.6~1.8g/㎤ was obtained when the fly ash was sintered at 120$0^{\circ}C$ in a weak reducing atmosphere. By maintaining the reducing atmosphere and sintering at a high heating rate, the liquid phase was farmed from the reduced composition of fly ash. This resulted in the formation of closed pores that enabled the low apparent density.

• Journal of the Korean Society of Clothing and Textiles
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• v.28 no.3_4
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• pp.396-402
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• 2004

The purpose of this study was to investigate the difference of cotton fabric texture perceived between on-line(screening fabric) and off-line(real fabric), and to analyze fabric characteristics having an effect on the difference. The similarity of 55 various cotton fabrics perceived between on-line and on-line were measured showing simultaneously real fabrics and screening fabrics by 7-scale questionnaire. And the characteristics of cotton fabrics such as weave structure, thickness, weight, fabric density, stiffness, Hunter's L, a, b, and hue were measured. Cotton fabrics were classified into 3 groups by extent of similarity. There were no significant differences in weft density, stiffness, Hunter's L, a, b, and hue among 3 groups. But there were significant differences in weave structure, thickness, weight, warp density, and difference of warp ＆ weft density. The fabrics having large similarity were thick and heavy, had small warp density and difference of warp ＆ weft density, and distinct surface texture. The group having medium similarity included fabrics of medium thickness and weight, having weak surface texture, large warp density and difference of warp ＆ weft density. The group having small similarity, which the differences between on-line and off-line were large, included thin and light fabrics having smooth surface and large warp density and difference of warp ＆ weft density.

• Economic and Environmental Geology
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• v.27 no.5
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• pp.479-489
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• 1994

In this paper, the iterative least-squares inversion method is used to determine shapes and density contrasts of 2-D structures from the gravity data. The 2-D structures are represented by their cross-sections of N-sided polygons with density contrasts which are constant or varying with depth. Gravity data are calculated by theoretical formulas for the above structure models. The data are considered as observed ones and used for inversions. The inversions are performed by the following processes: I) polygon's vertices and density contrast are initially assumed, 2) gravity are calculated for the assumed model and error between the true (observed) and calculated gravity are determined, 3) new vertices and density contrast are determined from the error by using the damped least-squares inversion method, and 4) final model is determined when the error is very small. Results of this study show that the shape and density contrast of each model are accurately determined when the density contrast is constant or vertical density gradient is known. In case where the density gradient is unknown, the inversion gives incorrect results. But the shape and density gradient of the model are determined when the surface density contrast is known.

• Applied Microscopy
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• v.19 no.2
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• pp.85-98
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• 1989

The ventricular myocardia of 14, 16, 18 and 20-day-old rat fetuses and newborns have been studies by light and electron microscopic morphometrics. The volume density of the myocyte and interstitial compartments as well as volume, surface and numerical density of nuclei were estimated by light microscopic morphometrics. Whereas, the volume density of myofibrils and glycogen granules as well as the volume, surface and numerical density of mitochondria were assessed by electron microscopic morphometrics. The volume density of myocyte compartment of the ventricular myocardia in developing fetuses decreased, but increased in newborn rats. On the other hand, the volume density of the interstitial compartment increased in growing fetuses and decreased in newborns. In all groups the volume, surface and numerical density of nuclei decreased gradually with elongation of myocytes. Conversely, the volume, surface and numerical density of mitochondria and volume density of myofibrils and glycogen granules in ventricular myocytes incresed. The increase in numerical density of mitochondria probably reflects an increase in metabolic activity. Sarcomere length also increased during development.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.2
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• pp.79-83
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• 2008

In this paper, we introduced a LIF measurement method and summarized the theoretical side. When an altered wavelength of laser and electric power, lamp applied electric power, we measured the relative density of the metastable state in mercury after observing a laser induced fluorescence signal of 404.8nm and 546.2nm, and confirmed the horizontal distribution of plasma density in the discharge lamp. Due to this generation, the extinction of atoms in a metastable state occurred through collision, ionization, and excitation between plasma particles. The density and distribution of the metastable state depended on the energy and density of plasma particles, intensely. This highlights the importance of measuring density distribution in plasma electric discharge mechanism study. The results confirmed the resonance phenomenon regarding the energy level of atoms along a wavelength. change, and also confirmed that the largest fluorescent signal in 436nm, and that the density of atoms in 546.2nm ($6^3S_1{\to}6^3P_2$) were larger than 404.8nm ($6^3S_1{\to}6^3P_2$). According to the increase of lamp applied electric power, plasma density increased, too. When increased with laser electric power, the LIF signal reached a saturation state in more than 2.6mJ. When partial plasma density distribution along a horizontal axis was measured using the laser induced fluorescence method, the density decreased by recombination away from the center.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.2
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• pp.109-115
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• 2004

This paper deals with the behaviors of magnetic flux density near down-conductors by lightning currents. The background on the principle of magnetic flux density measurements using the RL self-integrating magnetic field sensor was described. The magnetic flux density measuring device consisting of RL self-integrating magnetic field sensor and differential amplifier was designed and fabricated. The frequency bandwidth of the magnetic flux density measuring system ranges from 200 Hz to 300 KHz and the response sensitivity was 0.126 $\mu$T/㎷ The distributions of the magnetic flux density near down-conductors due to impulse currents with various rise times were analyzed as a parameter of the bonding conditions and materials of conductor and wiring conduits. The magnetic flux density due to impulse currents was inversely proportional to the distance between the down-conductor and measuring point. The amplitude of the magnetic flux density for PVC Pipe with down-conductor was 72 $\mu$T/㎷ at the distance of 1m and was higher than for steel conduits and coaxial cable. Finally the magnetic flux density is increased with increasing the di/dt it and oscillation frequency of lightning currents in this experimental ranges.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.438-438
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• 2010

The abnormal behavior of the argon metastable density during the E-H mode transition in argon ICP discharge was investigated. Lots of investigations including global models expected that during and after the mode transition of ICP discharge, the density of metastable increases with applied rf power (i.e. electron density). However, recent direct measurement of metastable density revealed that the metastable density of argon decreases with the applied power during and after the mode transition. This result may not be explained by the previous global model which is based on the assumption of the Maxwellian electron energy distribution function (EEDF). In this paper, to explain this abnormal behavior with simple manners, a simple global model taking account of the effect of the non-Maxwellian EEDFs incorporating into a set of coupled rate equations is proposed. The result showed that the calculated metastable density taking account of non-Maxwellian EEDF and its evolution during the transition has an abnormal behavior with electron density and is in good agreement with the previous measurement results, indicating the close coupling of electron kinetics and the behavior of metastable density. The proposed simple model is expected to provide qualitative kinetic insight to understand the behavior of the metastable density in various plasma discharges which typically exhibit non-Maxwellian distribution.

• Journal for History of Mathematics
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• v.17 no.2
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• pp.15-20
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• 2004

We investigate the unbiasedness and consistency as the statistical properties of density estimators. We show histogram, kernel density estimation, and local adaptive smoothing as density smoothing in this paper. Also, the early and recent research on nonparametric density estimation is described and discussed.