• Proceedings of the Korea Society of Design Studies Conference
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• 2001.10a
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• pp.54.1-54
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• 2001

• Bulletin of the Korean Chemical Society
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• v.7 no.6
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• pp.481-482
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• 1986

• Transactions of Materials Processing
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• v.16 no.1 s.91
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• pp.61-66
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• 2007

Powder injection molding(PIM) is widely used for many parts in the field of automotives, electronics and medical industries, due to the capability of net shaping for complex 3-D geometry. Powder injection mold design for the dental scaler tip, a component of medical appliance, was presented. In comparison with conventional machining process, powder injection molding has many advantages, specially in price and dimensional stability, for molding dental scaler tip which has complex geometry. Both product design and mold design for dental scaler tip were presented. A PIM feedstock was made of stainless series(17-4PH, 316L, 440C) powder and a wax based binder. The 'rapid mold' concept was applied to manufacture the various forms and materials of dental scaler tip including vibration characteristics.

• Journal of the Korean Applied Science and Technology
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• v.12 no.2
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• pp.59-64
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• 1995

Two aromatic polysulfones, poly(PhC-co-SDA)-2 and poly(TPhC-co-SDA)-2, were synthesized by interfacial polycondensation of phthaoyl chloride(PhC) and terephthaloyl chloride(TPhC) with P, P'-sulfonyldianiline(SDA), respectively. The properties of the aromatic polysulfones synthesized were as follows : inherent viscosity, $0.32{\sim}0.35dL/g$:glass transition temperature, $220{\sim}240^{\circ}C$:tensile strength, $308{\sim}336Kg/cm^2$:and 5% weight loss temperature by TGA thermogram in the air, $500{\sim}530^{\circ}C$. As the result, thermal properties of the synthesized copolymers proved to be excellent.

• Bulletin of the Korean Chemical Society
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• v.31 no.1
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• pp.41-46
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• 2010

In this work, we report on the characterization of six low-$T_g$ poly[methyl-3-(9-carbazolyl) propylsiloxane] based photorefractive (PR) composites sensitized with poly(3-hexylthiophene) (P3HT) in different concentrations, ranging from 0.2 to 1 wt %. At 632.8 nm, photoconductivity, space charge field, refractive index modulation, and grating buildup time were measured versus external electric field. The photoconductivity was strongly dependent on the visible light absorption and mobility. The magnitude of space charge field was affected by the conductivity contrast $\sigma_{ph}/(\sigma_{ph}+\sigma_d)$. The refractive index modulation increased with the magnitude of space charge field and the PR grating buildup speed increased with the photoconductivity.

• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.2947-2952
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• 2013

Three coordination polymers, [$ML_2(H_2O)_2$] (M = Co (1), Ni (2), Mn (3)), were prepared from metal acetates ($M(CH_3COO)_2{\cdot}4H_2O$) and 3-pyridinepropionic acid ($HL=(3-py)-CH_2CH_2COOH$) by solvent-layer methods. By contrast, a discrete molecular compound, trans-[$Pd(HL)_2Cl_2$] (4), was synthesized by replacing benzonitrile (PhCN) ligands in trans-[$Pd(PhCN)_2Cl_2$] with HL under microwave-heating conditions. Compounds 1-3 have a 2D framework, and compound 4 contains a square-planar Pd metal.

• Bulletin of the Korean Chemical Society
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• v.22 no.8
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• pp.833-836
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• 2001

Infrared absorption spectra of $\alpha\omega-diphenylpolyenyl$, anions Ph(CH)nPh- (DPn-, n=7, 9, and 13) in the tetrahydrofuran-d6 solutions was measured in the range of 1700 and 1200 cm-1 . The infrared spectra obtained from anions (DPn) showed considerable difference from their neutral species (DPn); their intensities were enhanced at least two orders of magnitude stronger than their neutral species. The in-plane CH bending modes at 1464 and 1375 cm-1 are correspondingly strengthened with the chain length increased, but the C=C stretching at 1541 cm-1 is weakened and frequencies are not changed. We provide an IR evidence for the first time that the bond order or bond alternations of the anions (soliton) are different from those of radical anions (polaron) as well as neutral species.

• Bulletin of the Korean Chemical Society
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• v.15 no.12
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• pp.1103-1107
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• 1994

Interaction of triethylsilane and diphenylsilane ($Ph_2$$SiH_2$, $Ph_2$$SiD_2$) with the surfaces of rhodium has been examined by trapping the reaction intermediates with 2,3-dimethyl-l,3-butadiene. 1,4-Hydrosilylation of the diene is predominantly observed to occur under mild condition over the rhodium catalyst. It is inferred from the product analyses that silylene and silyl radicals bonded to rhodium surfaces are the intermediates for addition of silylene to the diene, and for 1,4-hydrosilylation, respectively.

• Proceedings of the Technology Innovation Conference
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• 1996.12a
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• pp.77-98
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• 1996

This study is a critical assessment of research productivity through publication among scientists and engineers. This study scrutinizes previous findings on the correlates and determinant3 of publication productivity: Provides overview and organization of that knowledge ; indicates gape and shortcomings n the research; and identifies the questions and issues which are both answered and unanswered. through the analysis of the 223 mail questionnaires collected from professors of mechanical engineering, electrical engineering, chemistry and physics, this study obtains the particular determinants of publication productivity at the science and engineering schools in Korea. Especially, early research productivity and the number of doctoral students are very important to publish good research articles. Also the qualities of professors' Ph. D. institution and employing university are critical influencing factors to publication productivity. The data are analyzed using correlation, ANOVA, and multiple regression analysis and all the regression models are statistically significant. All the variables in this study are focused on the socialization of individual research scientists and any psychological or personal background variables are excluded, because the perspective of this article is not that of scientific sociologist but of science and technology Policy interest. This study proves that there exists an scriptive advantage according to the individual background such as his Ph. D. institution and employing university in Korea. This study also shows that all research resources and research performances are unequally distributed. This result proposes that supporting basic research at university must begins with relative assessment of researchers, departments, and institutions in consideration with their research environment and to evaluate researchers in compared with excellent research university like SNU, KAIST, POSTECH is unequal and inadequate.

• Computational Structural Engineering : An International Journal
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• v.1 no.2
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• pp.117-130
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• 2001

Investigations of low-rice unbounded reinforced concrete shear walls with or without openings are performed with comparison of analytical and experimental results. Theoretical analysis is based on nonlinear finite element algorithm, which incorporates concrete failure criterion and nonlinear constitutive relationships. Studios focus on the effects of height-to-length ratio of shear walls, opening ratio, horizontal and vertical reinforcement radios, and diagonal reinforcement. Analytical solutions conform well with experimental results. Equations for cracking, yielding and ultimate loads with corresponding lateral displacements are derived by regression using analytical results and experimental data. Also, failure modes of low-rise unbounded shear walls are theoretically investigated. An explanation of change in failure mode is ascertained by comparing analytical results and ACI code equations. Shear-flexural failure can be obtained with additional flexural reinforcement to increase a wall's capacity. This concept leads to a design method of reducing flexural reinforcement in low-rise bounded solid shear wall's. Avoidance of shear failure as well as less reinforcement congestion leer these walls is expected.