• International Journal of Highway Engineering
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• v.14 no.5
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• pp.93-99
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• 2012

PURPOSES: The purpose of this study is to compare the alkali-silica reactivity for mortar bar and concrete prism specimens using crushed aggregates of 5 types in Korea. And the alkali-silica reactivity for those aggregates are measured by chemical test method. METHODS: The alkali-silica reactivity for those aggregates was measured by chemical test method of KS F 2545, mortar-bar test of KS F 2546, accelerated mortar-bar test method of ASTM C 1260 and concrete prism test method of ASTM C 1293, relatively. RESULTS: The alkali-silica reactivity for those aggregates was verified by chemical test of KS F 2546 and accelerated mortar-bar test of ASTM C 1260. However, it was not by mortar-bar test of KS F 2546 and concrete prism test of ASTM C 1293. CONCLUSIONS: The above results showed that relationship among the four test methods were very low. The results from 3 types of test methods using cement-aggregate combinations appeared to be different. Because the environmental conditions of test methods for measuring the alkali-silica reactivity such as equivalent alkali content(external source), humidity, temperature, and times were different though the aggregates were same. Moreover, alkali-silica reactivity showed the biggest impact when alkalis were supplied form outside and exposed to environmental conditions. The accelerated mortar-bar test method seems to be most appropriate test method for concrete structures exposed to alkali environment.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.4
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• pp.337-343
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• 2000

Prism plane slip {11$\bar{2}$0}1/3{$\bar{1}$120} location velocity in sapphire ($\alpha$-Al$_2$O$_3$) single crystals was measured by etch-pit method. The dislocation velocities were measured as a function of temperature and stress between $1150^{\circ}C$ and $1400^{\circ}C$ for engineering stresses in the range 140 to 250 MPa. The dependence of temperature and stress in dislocation velocity was investigated. The activation energy for dislocation velocity was determined to be 4.2$\pm$0.4 eV. On the other hand, the stress exponent (m) describing the stress dependence of dislocation velocities was in the range of 4.5$\pm$0.8. Through this experiments, it was reconfirmed that the basal plane in sapphire single crystals has the 3-fold symmetry.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.1
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• pp.79-85
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• 2010

Purpose: We studied the relationship between subjective and objective deviating angle. Methods: Those who were diagnosed with strabismus among the patients who had no systemic diseases that fifty-one subjects (Male; 21, Female; 30) were measured between seven to sixty three years, evaluated to alternate cover test after AR/K (Canon RK-FI, Japan) and retinoscope measured refractive errors. Objective deviating angle was measured using prism bar; and subjective and objective deviating angles were measured and compared using the synoptophore. Results: For the correlation between subjective and objective deviating angles. The differences were $2.6{\pm}2.5{\Delta}$, between subjective deviating angle measured using synoptophore and objective deviating angles measured using synoptophore were $0.7{\pm}1.4{\Delta}$, the average with each other were $1.7{\pm}1.8{\Delta}$, with all the differences highly significant. Conclusions: We thought not only reduced angle of deviating errors and identified the significance in the correlation between subjective and objective deviating angles but also considered to be useful in determining deviating angle of patient with strabismus.

• Korean Journal of Optics and Photonics
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• v.18 no.6
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• pp.401-409
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• 2007

A new sheet of back light unit(BLU) to reduce the number of sheets and enhance the optical performances of direct back light unit(BLU) in a liquid crystal display is proposed and designed. In order to improve the straightness and spatial uniformity of brightness of the BLU, we design the new sheet with linear arrays of complicated bar prism by using the fusion of cylindrical lens and bar prism. Then, we investigate and analyze various optical performances of a BLU including the new sheet through an illumination optical system design program. From these results, we determine the optimum geometrical structure of the sheet. Under the optimum condition, the luminance efficiency and spatial uniformity of luminance of the BLU are 53.5% and 83.5% respectively. And the vertical and horizontal widths of the angular luminance distribution are $90^{\circ}$ and $112.5^{\circ}$ respectively. Finally we have fabricated a new BLU sheet according to this design shape by using an ordinary resins.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.197-200
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• 2006

The bond characteristics of three different types of glass fiber reinforced polymer(GFRP) reinforcing bars with different surface deformations were studied experimentally. Each specimen consisted of a concrete prism, 150 by 150 mm on each edge, with the longer axis in the vertical direction. Two rebars were embedded in each specimen, perpendicular to the longer axis and parallel to and equidistant from the sides of the prism. In vertical direction, one rebar was located at 75 mm from the bottom of the prism, and the other 225 mm from the bottom. All testing procedures including specimens preparation, set-up of test equipments and measuring devices were made according to the recommendations of CSA Standard S806-02.It was found that the bottom reinforcements showed higher bond stress than that of the top rebars.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.1 no.1
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• pp.60-65
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• 1991

The hydrothermal growth of $GaPO_{4}$ Single Crystals was carried out by the horizontal temperature gradient method. The most promising solvents for the crystal growth of $GaPO_{4}$ are $H_{3}PO_{4}$ and HCl solutions. Single crystals have been hydothermally grown at temperatures over the range $210-290^{\circ}C$ in these solutions with seed crystals. The glowth rates in HCl solution were higher than that for comparable conditions in $H_{3}PO_{4}$ solution. Morphologies of crystals grown at temperatures below $200^{\circ}C$ tended to be bounded by small major rhombohedral(10$\bar{1}$1) faces. In the temperature range from 200 to $430^{\circ}C$, the single crystals have morphologies bounded by prism (10$\bar{1}$0), small major rhombohedral(10$\bar{1}$1) and minor rhombohedral(01$\bar{1}$1) faces at the early stage, and grew with well developed basal(0001) faces by increasing the growth temperature.

• Computers and Concrete
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• v.18 no.3
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• pp.355-366
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• 2016

This paper reports the testing of concrete slabs reinforced with CFRP prestressed concrete prisms(PCP) on the flexural behavior. Four concrete slabs were tested, a reference slab reinforced with steel bars, and three slabs reinforced with CFRP prestressed concrete prisms (PCP). All slabs were made with dimensions of 600mm in width, 2200mm in length and 150 in depth. All concrete slabs reinforced with CFRP prestressed concrete prisms(PCP) exhibited CFRP bar rupture failure mode. It was shown that the application of the CFRP prestressed prisms can limit service load deflections and crack width, the increased level of prestress in the CFRP prestressed prism positively affected the maximum crack width. The deflection of concrete slabs reinforced with CFRP prestressed prisms decreased as prestress in the CFRP prestressed prism increased.

• Analytical Science and Technology
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• v.20 no.4
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• pp.355-360
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• 2007

The title complex, $(C_3H_{12}N_2)[\{Cd(H_2O)(C_6H_5O_7)\}_2]{\cdot}6H_2O$, I, has been prepared and its structure characterized by FT-IR, EDS, elemental analysis, ICP-AES, and X-ray single crystallography. It is triclinic system, $P{\bar{1}}$ space group with a = 10.236(2), b = 11.318(2), c = $13.198(2){\AA}$, ${\alpha}=77.95(1)^{\circ}$, ${\beta}=68.10(1)^{\circ}$, ${\gamma}=78.12(1)^{\circ}$, V = $1373.5(3){\AA}^3$, Z = 2. Complex I has constituted by protonated 1,3-diaminopropane cations, citrate coordinated cadmium(II) anions, and free water molecules. The central cadmium atoms have a capped trigonal prism geometry by seven coordination with six oxygen atoms of three different citrate ligands and one water molecule. Citrate ligands are bridged to three different cadmium atoms. Each cadmium atom is linked by carboxylate and hydroxyl groups of citrate ligand to construct an one-dimensional ladder-type assembly structure. The polymeric crystal structure is stabilized by three-dimensional networks of the intermolecular O-H${\cdots}$O and N-H${\cdots}$O hydrogen-bonding interaction.