• Journal of The Korean Astronomical Society
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• v.25 no.1
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• pp.23-46
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• 1992

The electrical, mechanical and optical capabilities have been tested of the microdensitometer PDS 1010GMS at the Korea Astronomy Observatory. The highest stage of scan speed 255 csu (conventional speed unit) is measured to be 47 mm/s. At this speed the position is displaced by $4{\mu}m$ to the direction of scanning and the density is underestimated by $0.4{\sim}0.7D$. Standard deviation in the measured density is proportional to $A^{-0.46}$, where A is the area of scan aperture. The accuracy of position repeatability is ${\pm}1{\mu}m$, and that of density repeatability is ${\pm}(0.003{\sim}0.03)D$. Callier coefficient is determined to be 1.37; the semispecular density is directly proportional to the diffuse density up to 3.5D. Because the logarithmic amplifier has a finite response time, the densities measured at high scan speeds are underestimated to the degree that speeds higher than 200 csu are inadequate for making an accurate astronomical photometry. After power is on, an about 5 hour period of warming is required to stabilize the system electrically and mechanically as well. On the basis of this performance test, we have determined the followings as the optimum scan parameters for the astronomical photometry: For the scan aperture $10\;\sim\;20{\mu}m$ is optimal, and for the scan speed. $20\;{\sim}\;50$ csu is appropriate. These parameter values are chosen in such a way that they may keep the density repeatability within ${\pm}0.01D$, the position displacement under $1{\mu}m$, and the density underestimation below 0.1D even in high density regions.

• Journal of the Korean Geotechnical Society
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• v.38 no.10
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• pp.41-48
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• 2022

The mass density of the medium (ρ) used to calculate the maximum shear modulus (G_max) of the saturated ground based on the shear wave velocity is unclear. Therefore, to determine the mass density, a verification formula and five scenarios were established. Laboratory tests were conducted, and the obtained results were compared. The mass density of the medium was assumed to be saturated (ρ_sat), wet (ρ_t), dry (ρ_dry), and submerged conditions (ρ_sub), and the V_s ratios of saturated to dry condition were obtained from each case. Assuming the saturated density (ρ_sat), the V_s ratio was consistent with the value from the resonant column test (RCT) results, and the value from the bender element test results was consistent with the wet density assumption (ρ_t). Considering the frequency range of earthquakes, it is concluded that applying the saturated density (ρ_sat) is reasonable as in the RCT results.

• Proceedings of the Korea Concrete Institute Conference
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• 1994.10a
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• pp.399-404
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• 1994

Heavyweight(or High density) concrete, which is generally for shiedling structures, differs from normal weight concrete by having a higher density and special compositions to improve its attenuation properties. There are setting 7 Beam Ports around the reactor of the KMRR Project(Korea Multi-purpose Research Reactor) conducted by the KAERI(Korea Atomic Energy Research Institute). High density(p=5.0t/$\textrm{m}^3$) and Heavyweight(p=3.5t/$\textrm{m}^3$) concrete were placed around the Beam Ports in order to shield radiation. This paper was discussed about construction of High density concrete. High density concrete was placed with method of Preplace Aggregate. Coarse metallic aggregate(steel shot) was used. Boron, boron carbide(B4C), was used to capture effctively the neutrom. The mock-up test was carried out. And the consturction of High density concrete was performed successfully.

• Journal of the Korean Society of Safety
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• v.25 no.1
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• pp.38-43
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• 2010

The smoke density and noxious gas for phenol foam and polyurethane foam were measured according to test methods in ASTM E 662 and KS F 2271. It was observed that phenol foam had the possibility of application for sandwich panel and board compared with polyurethane foam. In the experimental results, phenol foam showed comparatively excellent property than polyurethane foam in smoke density and noxious gas. The polyurethane foam showed comparatively high smoke density and didn't meet the evaluation standard of noxious gas in KS F 2271. From the experimental results of smoke density and noxious gas, it can be said that phenol foam has both comparatively good safety and high possibility of application than polyurethane foam in the building fire of sandwich panel structure because of lower smoke density and noxious gas.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.53-54
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• 2011

The facilities producing the nuclear energy chosen for resolving the recent global energy problem have been increasingly constructed, and hence more frequent durability tests on radiation shielding concrete are required due to NPP(Nuclear Power Plant) life extension and increase of radioactive waste repositories. Bulk dry density is one of the critical factors ensuring the durability and performance of the radiation shielding concrete because the design of the radiation shielding reinforced concrete structures for NPPs is based on the bulk dry density of the concrete. Bulk density of unconsolidated shielding concrete can be calculated utilizing a test assuring to satisfy the bulk dry density, or existing credible data set. This study evaluated correlation between bulk density and bulk dry density of the concrete used for Korean NPPs (y=1.0913X-0.2458) and developed a correlation expression considering standard deviation of bulk dry density (y=1.0913X-0.3358).

• Journal of IKEEE
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• v.5 no.1 s.8
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• pp.43-51
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• 2001

As the density of memories increases, unwanted interference between cells and coupling noise between bit-lines are increased. And testing high-density memories for a high degree of fault coverage can require either a relatively large number of test vectors or a significant amount of additional test circuitry. So far, conventional test algorithms have focused on faults between neighborhood cells, not neighborhood bit-lines. In this paper, a new test algorithm for neighborhood bit-line sensitive faults (NBLSFs) based on the NPSFs(Neighborhood Pattern Sensitive Faults) is proposed. And the proposed algorithm does not require any additional circuit. Instead of the conventional five-cell or nine-cell physical neighborhood layouts to test memory cells, a three-cell layout which is minimum size for NBLSFs detection is used. Furthermore, to consider faults by maximum coupling noise by neighborhood bit-lines, we added refresh operation after write operation in the test procedure(i.e.,$write{\rightarrow}\;refresh{\rightarrow}\;read$). Also, we show that the proposed algorithm can detect stuck-at faults, transition faults, coupling faults, conventional pattern sensitive faults, and neighborhood bit-line sensitive faults.

• Journal of Naturopathy
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• v.7 no.2
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• pp.63-69
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• 2018

Purpose: The purpose of this study was to investigate the effects of Bacillus fermentation broth (ENM) on the human NK cell activity, and bone matrix density, matrix content and area of hamsters fed ENM. Methods: NK cell activity was tested, and bone mineral density were measured by x-ray. Results: NK cell activity was significantly higher in the control group (644.71 pg/ml) and in the test group (1796.37 pg/ml) (p<.004). Test groups were significantly increased by 1110.37 pg/ml in the pre-test and 1796.37 pg/ml in the post-test(p<.001). Behavioral observations after feeding ENM to hamsters showed normal behavior with no difference between control and test groups. The hamster body weight of the control was 106 g at the initial and final 27 days. In the test group, the initial weight was 96.6 g and the final 27 days was 114 g. No morphological changes were observed in the X-ray photographs of the hamster hind legs. The bone matrix density was 0.059 g/cm³ in control and 0.062 g/cm³ in the test, which was increased by 0.003 g/cm³. The bone matrix content was 0.175 g in the control and 0.196 g in the test. The bone area was 2.95 cm² in the control and 3.19 cm² in the test, which was increased by 0.19 cm². In the autopsy, neither the control nor the test group showed any remarkable abnormality, and each organ was normal. Conclusions: It is thought that ingestion of ENM is useful for immunity enhancement.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.1
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• pp.96-103
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• 2005

To analyze the reason of aging deterioration in transmission line insulators, we performed a various kind of test and investigated mechanical and electrical characteristics of insulators. Test samples consisted of K-1989(36,000lbs), K-1995(36,000lbs) and K-2001(36,000lbs) type insulators which have been used in domestic 154 kV transmission lines. As a result of this test, the facts turned out K-2001 insulator which contain 17 wt.% alumina has better physical characteristics than K-1989 insulator which contain 8 wt% alumina. Relativity density and fracture toughness of K-1989 porcelain are 94.2 % and 1.4 MPa\ulcornerm$^{1}$2// but relativity density and fracture toughness of K-2001 porcelain are 96 % and 1.7 MPa\ulcornerm$^{1}$2//. K-2001 insulators show a good performance not only in a physical property test but also in power arc test and steep front of wave flashover test which is performed to evaluate electrical characteristics.

• Research in Community and Public Health Nursing
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• v.8 no.1
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• pp.31-44
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• 1997

The purpose of this study was to measure and determine the relationship of femoral neck and lumbar bone mineral density with their and related factors. It were measured and determined the relationships among bone mineral density, bone mineral content in the lumbar and femoral neck, muscle strength (arm, back, leg), muscle endurance, instrumental activity of daily living (IADL), quality of life, cognitive perceptual variables(self efficacy, perceived health status), age, age at menopausal period. The twenty five subjects participating in this study consisted of twelve males and thirteen females at a C-institution in Chung Buk province. The mean age of subjects was 73.64 years. The data was collected from August, 1993 to September, 1993. The data was analyzed with $x^2-test$, t-test, Correlation, multiple regression using a SPSS pc+ program. 1. The mean femoral neck bone mineral density was $0.636g/cm^2$, 66.7% of young bone mineral density, the mean lumbar($L_2-L_4$) bone mineral density was $0.807g/cm^2$, 79.86% of young bone mineral density. The mean fermoral neck bone mineral content was 2.906g and the mean lumbar bone mineral content was 36.898g. 2. The mean muscle strength was 17.14kg(grip strength), 32.05kg(back lift strength), 17.14kg (leg lift strength) and the mean muscle endurance was 9.92times. 3. Men showed a significantly higher score (p<0.01) in muscle strength and muscle endurance than women, as well as a significantly higher score on self efficacy and perceived health status(p<0.05). 4. The femur neck bone mineral density had a significant correlation(p<0.0l) with leg lift strength, back lift strength, and their was a significant correlations (p<0.05) with arm strength and muscle endurance. Lumbar ($L_2-L_2$) bone mineral density had a significant correlation(p<0.05) with muscle endurance, grip strength and IADL. 5. With the multiple regression analysis the most significant predictor for lumbar bone mineral density were IADL, the most significant predictor for femoral neck bone mineral density was leg strength. This study concluded: As the mean bone mineral density and bone mineral content were low, the aged showed osteopenia. Bone mineral density, muscle strength and IADL were correlated. The aged could pro mote muscle strength, bone mineral density and IADL through Leg Press exercise which was safe and efficient for the aged. This Leg Press exercise contributed to prevention of osteoporosis and promoted the health of the aged.

• KIEE International Transactions on Electrophysics and Applications
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• v.4C no.2
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• pp.68-72
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• 2004

The performance of copper-tungsten for electrodes used in an ultra high voltage interruption system was evaluated by means of an interruption test, which requires a large-scale apparatus and high cost. In this study, prior to the interruption test, the characteristics of a Cu-W electrode were estimated through the DC arc test, which is a simple, low cost procedure. The DC arc characteristics of a 20wt%Cu-80wt%W electrode were investigated with the change of tungsten powder size distribution and the addition of nickel. In specimens containing a high volume fraction of large sized tungsten particles, the relative density and hardness of sintered Cu-W electrodes increased while the electrical conductivity and the DC arc resistance decreased. Furthermore, the relative density became enhanced with the increase of the amount of nickel while the hardness and electrical conductivity diminished and the DC arc resistance worsened.