• KSBB Journal
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• v.16 no.6
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• pp.533-537
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• 2001

${\alpha}$-lactalbumin and ${\beta}$-lactoglobulin in whey proteins were separated by high performance membrane chromatography (HPMC). The separation mechanism involved anion-exchange, and the stationary phase was anion CIM (Convective Interaction Media) DEAE, QA disk and cation exchanger SO$_3$(16${\times}$3 mm). Two types of mobile phase were used, buffer A (20 mM Tris-HCI, pH 7.3) and buffer B(buffer A + 1 M NaCl), As the amount of NaCl dissolved in buffer linearly increased, which enabled a gradient elution mode. The optimum mobile phase and operating condition (Buffer A/Buffer B = 100/0 - 30/70 vol%, gradient time 1 min, 30/70 - 10/90 vol.%, gradient time 2 min) were experimentally determined. In this experimental condition, ${\alpha}$-lacta1bumin, ${\beta}$-lactoglobulin were separated within 5 min at a mobile phase flow rate of 4 mL/min.

• Composites Research
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• v.26 no.2
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• pp.123-128
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• 2013

The PVDF (polyvinylidene fluoride) fibers were prepared using the wet spinning processing. To improve ${\beta}$-phase crystalline which closely related piezoelectric property PVDF wet spun fibers conducted post treatment. Post treatment is consisted of heat stretching and annealing process. The heat stretching and annealing conditions were controlled by changing temperature between glass transition temperature and melting temperature. From these experimental data, the resulting crystal structure of the ${\beta}$-phase crystalline was confirmed by FT-IR and XRD experiments. From these analysis results, optimum stretching and annealing conditions of the wet spun PVDF fibers were founded to increase high ${\beta}$-phase crystalline. Furthermore results showed that thermal processing had a direct effect on modifying the crystalline microstructure and also confirmed that heat stretching and annealing could increase the degree of crystallinity and ${\beta}$-phase crystalline. Finally, piezoelectric constant ($d_{11}$) of the post heat treated PVDF fibers reinforced composite were measured to investigate the feasibility for the sensing materials.

• Journal of Technologic Dentistry
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• v.28 no.1
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• pp.27-41
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• 2006

The physical property and phase transformation in a commercial dental casting high gold alloy was investigated as a function of ageing temperature and time using microvickers hardness tester, X-ray diffraction, optical and electron microscopy and EPMA analyser. 1. With increasing ageing time, the hardness of solution-treated gold alloys increased slowly at the initial stage of ageing treatment at an ageing temperature of $300{\sim}400^{\circ}C$, and it reached a maximum value of hardness at the medium stage. Finally, it decreased gradually during further ageing. The maximum value of hardness at was similar with that of the conventional materials and suitable for using as the crown & bridge. 2. During isothermal ageing at a temperature range of $300{\sim}400^{\circ}C$, three phases consisting of the Au-rich ${\alpha}_1$phase with a face-centered cubic structure, the Pt3Zn ${\alpha}_2$phase with an ordered AuCu3(L12) type(f.c.c.) and the Pt-rich ${\alpha}_3$phase with face-centered cubic structure in solution-treated gold alloys were transformed into different three phases consisting of the ${\alpha}_1$phase, the ${\alpha}_3$phase and the PtZn $\beta$phase with an ordered AuCu I(L10) type. 3. The hardening of gold alloys was attributed to the lattice strains of the matrix resulting from the transformation of the ${\alpha}_2$phase to the $\beta$phase. 4. The softening of gold alloys during over-ageing was attributed to the coarsening of the nodules consisting of the $\beta$phase and ${\alpha}_1$matrix.

• Journal of Mechanical Science and Technology
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• v.20 no.1
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• pp.13-18
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• 2006

Ti-8Ta-3Nb, as a new biomaterial, was prepared by cast and swaging process. Their deformation behavior of Ti-8Ta-3Nb alloy has been characterized on the basis of its flow stress variation obtained from the true strain rate compression testing in the temperature of $700-900^{\circ}C$ and strain rate of $0.001-10\;s^{-1}$. At the strain rates lower than $0.1\;s^{-1}$ and the all temperature ranges which consist of two phase ${\alpha}+{\beta}$ as well as single ${\beta}$ phase fields, the flow curves show a small degree of flow softening behavior. In contrast, the shapes of the flow curves at other strain rates indicate unstable behavior. The shapes of the flow curves were similar in both as-cast and swaged specimen as well as in both ${\alpha}+{\beta}$ phase and ${\beta}$ phase. The flow stress data did not obey the kinetic rate equation over the entire regime of testing but a good fit has been obtained in the intermediate range of temperatures ($750-850^{\circ}C$). In this range, a stress exponent value of about 7.7 in as-cast specimens and about 6.2 in swaged specimens with an apparent activation energy of about 300 kJ/mol and about 206 kJ/mol respectively have been evaluated.

• Journal of the Korean Society for Heat Treatment
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• v.27 no.3
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• pp.115-120
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• 2014

Microstructural features were comparatively investigated in AZ91 (Mg-9%Al-1%Zn) and AZ91-0.5%Sn alloys, in order to clarify the reason for the enhancement in room temperature tensile properties by the addition of small amount of Sn in Mg-Al-based alloy. In as-cast state, the Sn-containing alloy showed increased YS, UTS and elongation than the Sn-free alloy. The microstructural examination revealed that various factors including finer cell size, reduction of lamellar (${\alpha}+{\beta}$) phase and morphological change of bulky ${\beta}$ phase from partially divorced shape to fully divorced shape, are likely to be responsible for the improvement in tensile properties for the Sn-containing alloy. It is noted that two alloys showed similar tensile properties after solution treatment. This implies that microstructural evolution related to the ${\beta}$ phase plays a key role in better tensile properties in the Sn-containing alloy.

• Journal of the Korean Society for Heat Treatment
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• v.16 no.2
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• pp.90-96
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• 2003

The effect of betatizing temperature on microstructure and transformation characteristics in a Cu-AI-Ni based pseudoelastic alloy fabricated by heated mold continuous casting by using metallography, XRD and calorimetry. The microstructure of cast rod betatized at $600^{\circ}C$ revealed a ${\beta}_1$ parent phase and a ${\gamma}_2$ phase precipitated along the casting direction. When the cast rod was betatized at the elevated temperature above $600^{\circ}C$, the ${\gamma}_2$ phase is completely dissolved into the matrix so that the volume fraction of the ${\gamma}_2$ phase was decreased. The parent phase was stabilized by betatizing at $600^{\circ}C$. However, the ${\beta}_1$ parent phase was transformed to both ${{\beta}_1}^{\prime}$ and ${{\gamma}_1}^{\prime}$ martensites with increasing betatizing temperatures above $600^{\circ}C$, while $M_s$ and $A_s$ temperatures were decreased. The stress-strain curves for compression test were not same with betatizing temperature; the stress-strain curves of the specimen betatized at $600^{\circ}C$ and $700^{\circ}C$ were linear but those of the specimen betatized at $800^{\circ}C$ and $900^{\circ}C$ were not linear.

• Journal of the Korean Ceramic Society
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• v.23 no.3
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• pp.1-8
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• 1986

The preparation and electrical conductivity of $\beta$-$Al_2O_3$ are investigated as a function of $Na_2O$ content from the-oretical composition of $\beta$-$Al_2O_3$ to that of $\beta$"-$Al_2O_3$. $\beta$-$Al_2O_3$ $\beta$"$Al_2O_3$$\alpha$-Al2O3 and ${\gamma}$-NaAlO2 phases appear in the calcined powder at 125$0^{\circ}C$ for 2 hours. The majoity phase is $\beta$-$Al_2O_3$ in sintered specimens at 155$0^{\circ}C$ and 1$650^{\circ}C$ for 30 mins respectively and ${\gamma}$-4NaAlO_2$ phase also exists when Na2O content is over 10.39w/o ${\gamma}$-4NaAlO_2$ phase does not affect the grain growth of $\beta$-$Al_2O_3$ in sintering at 155$0^{\circ}C$ but acts as a reactive liquid for the abnormal grain growth of $\beta$-$Al_2O_3$in sintering at 1$650^{\circ}C$ The electrical conduction of $\beta$-$Al_2O_3$is predominated by 4Na^+$ ion. Contribution of ionic con-ductivity to total conductivity is gradually decreased with increasing temperature at given oxygen pressure and to -tal conductivity is increased by positive hole due to interstitial oxygen with increasing oxygen pressure.

• Journal of Korea Foundry Society
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• v.9 no.1
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• pp.58-66
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• 1989

The effect of heat treating temperature and ${\alpha}$ phase In the ${\beta}$ phase matrix were investigated for ${\beta}-CuZnAl$ shape memory alloys by tension test, fatigue test, and shape memory effect test. After heat treatment at $677^{\circ}C$, $750^{\circ}C$, $800^{\circ}C$ and $850^{\circ}C$ for 10 min. respectively, static fracture stress(${\sigma}_f$), fatigue fracture stress(${\tau}_{max}$) at $10^6$ cycle, and elongation(${\epsilon}_f$) was $24.2kg/mm^2$, $17.21kg/mm^2$ and 11.8%, respectively. As heat treating temperature decreased, fracture surfaces of the specimens were changed from the intergranular to the transgranular fracture mode. Especially, the a phase precipitated in the ${\beta}$ phase matrix had an effect on crack propagation and the fracture surface was characterized by dimple-like pattern when crack propagated in transgranular cracking mode. Precipitation of the ${\alpha}$ phase in the ${\beta}$ phase matrix lowered the transformation temperature by $10^{\circ}C$, and about 2.5 vol.% ${\alpha}$ phase did not affect the shape memory effect examined by the bending test.

• The Korean Journal of Physiology and Pharmacology
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• v.9 no.1
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• pp.23-27
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• 2005

The present study was performed to investigate the effects of intra-articular injection of interleukin-1${\beta}$ (IL-1${\beta}$) on the formalin-induced temporomandibular joint (TMJ) pain. Under anesthesia, a 30-gauge needle was introduced into the right TMJ region for injection of formalin. Microinjection of 50 ${\mu}l$ of 5% formalin significantly produced noxious scratching behavioral response, and the scratching behavior lasted for 40 min. Although the responses produced by formalin injection were divided into two phases, the response of 1st phase did not significantly differ from the scratching behavior response in the saline-treated group. We examined the effects of intra-articular injection of IL-1${\beta}$ on the number of noxious behavioral responses produced by 50${\mu}l$ of 5% formalin injection. Intra-articular injection of 100 pg and 1 ng of IL-1${\beta}$ significantly increased the number of behavioral responses of the 2nd phase, while 10 pg of IL-1${\beta}$ did not change the formalin-induced behavioral responses. To investigate whether IL-1 receptor was involved in the intra-articular administration of IL-1${\beta}$-induced hyperalgesic response, IL-1 receptor antagonist (IL- ra, 50 ng) was administrated together with IL-1${\beta}$ injection. IL-1${\beta}$ receptor antagonist blocked IL-1${\beta}$- induced hyperalgesic response in the TMJ formalin test. These results suggest that intra-articular injection of IL-1${\beta}$ facilitated the transmission of nociceptive information in the TMJ area.

• YAKHAK HOEJI
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• v.38 no.1
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• pp.78-85
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• 1994

From phase solubility studies bile acids and bile salts were found to form stable inclusion complexes with ${\beta}-cyclodextrin$ in aqueous solution. Stability constant of bile acids were larger than that of bile salts. Phase solubility diagrams of most bile acids showed Higuchi's $A_I$ type but lithocholic acid showed $B_S$ type. Not only the solubility of bile acids but also that of ${\beta}-cyclodextrin$ increased, especially in cases of cholic acid and ursodeoxycholic acid. Solubility increase of bile acids from their ${\beta}-cyclodextrin$ inclusion complex followed the order : cholic acid>ursodeoxycholic acid>chenodeoxycholic acid>deoxycholic acid>lithocholic acid. It seems that solubility of inclusion complexes was directly related with the hydrophilicity of bile acids.