• Korean Journal of Materials Research
• /
• v.9 no.3
• /
• pp.240-243
• /
• 1999

Piezoelectric properties of O.9PMN-0.1PT relaxor ferroe1ectrics were investigated in the temperature range of $-40^{\circ}C~$100^{\circ}C$. After poled at $-40^{\circ}C$, electro-mechanical properties of the samples were measured by resonance antiresonance method. As the resonance behavior was shown in impedance spectrum obtained below $0^{\circ}C$, it can be c conduded that 0.9PMN-0.1PT is bona-fide ferroelectrics below the phase transition temperature. It is very noteworthy that electro-mechanical resonance occurs at the temperatures far above the phase transition temperature. It is coneluded that ferroelectricity in 0.9PMN-0.1PT relaxor were verified far above the phase transition temperature.

• Biomedical Science Letters
• /
• v.12 no.3
• /
• pp.197-200
• /
• 2006

We analyzed total protein (TP), albumin (AL), aspartic aminotransferase (AST), alanine aminotransferase (ALT), urea nitrogen (UN), creatinine (CRE) and serum protein electrophoretic fractions in sera of rural elderly patients to evaluate the health status in rural elderly patients. We observed that the frequencies of patients showed lower level of total protein, albumin, and both total protein and albumin than them of reference range were 20.3%, 22.8% and 19.0%, respectively. The rates of patients showed higher level of AST, ALT, both of AST and ALT, UN, creatinine and both of UN and creatinine than them of reference range were 33.8%, 40.0%, 30.0%, 17.7%, 15.2% and 7.9%, respectively. Comparison of protein fractions of each patient to reference range showed that 77.2% of patients showed normal in all of patterns. Few of patients showed abnormal pattern in albumin (13.6%), ${\alpha}1-globulin (0.0%),\;{\alpha}_2-g10bulin(1.1%),\;{\beta}-globulin(1.9%)\;and\;{\gamma}-globulin(6.2%)$. These data suggest that many of rural elderly patients may suffer from heart, liver and kidney diseases. The serum protein fractions are not typical criterion to evaluate the disease, but production of proteins in rural elderly patients may be affected by liver disease and kidney disease.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.23 no.1
• /
• pp.37-43
• /
• 2013

Conductivity of LSGMC materials were affected by secondary phase segregation, composition and synthetic route. $La_{0.8}Sr_{0.2}Ga_{0.8}Mg_{0.1}Co_{0.1}O_{3-{\delta}}$ (LSGMC) powders were prepared using the glycine nitrate process to produce high surface area and compositionally homogeneous powders. The powders were synthesized with different 0.5, 1, 1.5, 2, 2.5 of glycine/cation molar ratios. A single perovskite phase from the synthesized powders was characterized with X-ray diffraction patterns. The obtained sintered pellets showed the dense grain microstructure. In case of 1.5 molar ratio, its density was higher than the others. The electrical conductivity measured at $800^{\circ}C$ was observed to be 0.131 $Scm^{-1}$. In addition, the linear thermal expansion behavior was indicated between $25^{\circ}C$ and $800^{\circ}C$.

• Microbiology and Biotechnology Letters
• /
• v.11 no.3
• /
• pp.193-199
• /
• 1983

Systematic bioconversion process for the production of xylose from agricultural wastes such as barley straw and corn cobs was studied. After the pretreatment in 1 % NaOH solution for 24 hours at 3$0^{\circ}C$, enzymatic hydrolysis of barley straw for 48 hours at 3$0^{\circ}C$ resulted in the liberation of 15.8% of reducing sugar which is equivalent to 87% of total D-xylose content. Among various agricultural wastes, corn cob as well as barley straw was demonstrated to be potent sources for the production of D-xylose by the process of enzymatic conversion.

• Proceedings of the Korean Ceranic Society Conference
• /
• 2003.10a
• /
• pp.102.1-102
• /
• 2003

• Journal of Welding and Joining
• /
• v.25 no.3
• /
• pp.57-63
• /
• 2007

Electrochemical migration characteristics of Pb-free solder alloys are quantitatively correlated with corrosion characteristics in harsh environment conditions. In-situ water drop test and corrosion resistance test for Sn-3.0Ag-0.5Cu solder alloys were carried out in NaBr and NaF solutions to obtain the electrochemical migration lifetime and pitting potential, respectively. Sn-3.0Ag-0.5Cu solder alloy shows similar ionization and electrochemical migration behavior with pure Sn because of Ag and Cu do not migrate due to the formation of resistant intermetallic compounds inside solder itself. Electrochemical migration lifetime in NaBr is longer than in NaF, which seems to be closely related to higher pitting potential in NaBr than NaF solution. Therefore, it was revealed that electrochemical migration lifetime of Sn-3.0Ag-0.5Cu solder alloys showed good correlation to the corrosion resistance, and also the initial ionization step at anode side is believed to be the rate-determining step during electrochemical migration of Pb-free solders in these environments.

• Journal of Animal Science and Technology
• /
• v.64 no.3
• /
• pp.462-470
• /
• 2022

The addition of dietary proteases (PRO) to weaner diets hydrolyzes soybean-based anti-nutritive factors and improves weaned pig's dietary digestibility and growth performance. Therefore, this study explores the effects of PRO in a lower crude protein (CP) level diet than that in a commercial diet on the growth performance, nutrient digestibility, and intestinal morphology of weaned pigs. A total of 90 weaned pigs were randomly assigned to 3 dietary treatments with 6 pigs per pen and 5 replicated pens per treatment using a randomized complete block design (block = body weight [BW]): 1) a commercial weaner diet as a positive control (PC; phase1 CP = 23.71%; phase2 CP: 22.36%), 2) lower CP diet than PC as a negative control (NC; 0.61% less CP than PC), and 3) an NC diet with 0.02% PRO. Pigs fed PC and PRO had higher (p < 0.05) final BW, average daily gain, and/or gain to feed ratio for the first three weeks and the overall experimental period than NC. The PC and PRO groups had greater (p < 0.05) apparent ileal digestibility of dry matter, CP, and energy than the NC group. Moreover, pigs fed PC and PRO increased (p < 0.05) apparent total tract digestibility of CP compared with those fed NC. In addition, the PRO group had a higher number of goblet cells than the PC and NC groups. However, pig fed PC and PRO increased (p < 0.05) villus height and height to crypt depth ratio in the ileum compared with those fed NC. In conclusion, PRO supplementation in a commercial weaner diet with low CP levels improves growth rate and nutrient digestibility by modulating the intestinal morphology of weaned pigs.

• Proceedings of the KSAR Conference
• /
• 2001.03a
• /
• pp.39-39
• /
• 2001

Effects of Barodon$^{(R)}$ on body growth, histological changes in seminiferous tubules of testes and serum level of testosterone and FSH were examined in juvenile rats from 5 to 38 wks of age. All rats supplied feed and Barodon-added water(0, 0.1, 0.15, 0.3 and 1.0%) available ad libitum. DNA distribution of testicular cells from control rats obtained by flow cytometry was characterized by 4 peaks representing I : elongated, II round spermatids(1N), III: a variety of 2N cells and IV: 4N cells. Frequencies of 4 testicular cell types were calculated using cumulative DNA frequency distributions. Body growth from 18wk of age was significantly accelerated in rats supplied water with 0.15% Barodon compared to other groups. Testes weights tended to be greater in 0.15% Barodon-treated rats than in control, without significant difference. Diameter of seminiferous tubules advanced in 0.15-0.3% Barodon till 26 wk of age, but there was not significant different. Proportion of spermatids in seminiferous tubules was 48.4% at 6wk of age(round: 81.2% and elongated: 18.8% as proportion of total spermatids) and frequency of spermatids was higher in 0.3% Barodon group(57.1%) than in control(44.0%), but there was no significant difference. Serum testosterone of all groups significantly elevated at 18wk of age and level in 0.15% Barodon group was greatly higher than in others. Serum FSH at 10wks was greatly higher in 0.1-0.3% Barodon groups compared to control, but there were no significant differences. It is concluded that 0.15-0.3% Barodon treatment tended to induce precocious puberty in rats.

• Journal of the Korean Ceramic Society
• /
• v.44 no.4 s.299
• /
• pp.214-218
• /
• 2007

The decrease of polarization resistance in cathode is the key point for operating at intermediate temperature SOFC (solid oxide fuel cell). In this study, the influence of Co substitution in B-site at complex perovskite on the electronic conductivity of PSCM ($Pr_{0.3}Sr_{0.7}Co_xMn_{(1-x)}$) was investigated. The PSCM series exhibits excellent MIEC (mixed ionic electronic conductor) properties. The ASR (area specific resistance) of PSCM3773 was $0.174{\Omega}{\cdot}cm^2\;at\;700^{\circ}C$. The activation energy of PSCM3773 was also lower than other compositions of PSCM. The TEC(thermal expansion coefficient) was decreased by addition of Mn. The ASR values were increased gradually during the thermal cycling test of PSCM37773 due to the delamination between electrolyte and cathode materials. The delamination was caused by the difference of TEC.

• Bulletin of the Korean Chemical Society
• /
• v.14 no.1
• /
• pp.86-91
• /
• 1993

A synthetic route to (+)-isocarbacyclin starting from (-)-tricyclo[3.3.0.0$^{2.8}$]octan-3-one 6 is described. The key intermediate 4 has been synthesized from 6 by a sequential introduction of methoxycarbonyl group at C-12 and the oxygen functionality at C-9${\alpha}$(PG numbering) for the construction of ${\alpha}-and\;{\omega}$-side chain, and then converted to isocarbacyclin methyl ester 2.