• Journal of Aquaculture
• /
• v.17 no.1
• /
• pp.46-50
• /
• 2004

In the present study, attempts were made to cryopreserve sea urchin, Anthocidaris crassispina sperm in liquid nitrogen, to evaluate the effects of various cryoprotectants and freezing rates on motility, survival rate and fertilization rate of the post-thawing sperm, and the ultrastructural changes of sperm after cryopreservation were observed. The highest values of sperm motility (motility index: 3.3$\pm$0.37) and survival rate (72$\pm$3.5%) were obtained with 15% dimethyl sulfoxide (DMSO), and these values were significantly higher than those of sperm preserved with glycerol. Comparisons of motilities and survival rates between treatments of difference freezing rates showed that there was no difference between procedures (a) 5$0^{\circ}C$/min to -8$0^{\circ}C$ (motility index: 3.3$\pm$0.31 ; survival late 70$\pm$2.7%) and (b) 3$0^{\circ}C$/min to -8$0^{\circ}C$ (motility index: 3.1$\pm$0.29; survival rate 69$\pm$3.7%), while the results of (c) 1$0^{\circ}C$/min to -8$0^{\circ}C$ were significantly lower than the others (motility index: 2.2$\pm$0.33 ; survival rate 42$\pm$4.6%). There was no significant difference in fertilization rate between fresh sperm and sperm preserved with 15% DMSO as cryoprotectant and freezing rate (3$0^{\circ}C$/min to -8$0^{\circ}C$). Some ultrastructural changes of sperm, such as the detachment of plasma membrane, the destruction of mitochondria, and the flagellum rolling up head, were observed after cryopreservation. Morphological normality of the sperm in 15% DMSO frozen at the ratio of 5$0^{\circ}C$/min to -8$0^{\circ}C$ was better than the others.

• Korean Journal of Food Science and Technology
• /
• v.14 no.2
• /
• pp.125-129
• /
• 1982

Four peroxidase isozymes from horseradish roots (isozymes A, B, C and D) were isolated by chromatography and were thermally inactivated at $70{\sim}97^{\circ}C$ and pH 7.0. The four isozymes had different inactivation rates and the inactivation of each isozymes did not follow first order kinetics. D values of isozymes A, B, C, D and crude enzyme were 594s, 1850s, 2050s, 78s, 130s and z values were $24.0^{\circ}C$, $12.5^{\circ}C$, $18.0^{\circ}C$, $23.7^{\circ}C$ and $24.0^{\circ}C$, respectively. Sephadex gel chromatogram of the thermally treated isozyme C indicated that the shape and molecular weight of the native isozyme changed during inactivation.

• Nuclear Engineering and Technology
• /
• v.8 no.1
• /
• pp.19-27
• /
• 1976

The strain ageing behaviour of Zircaloy-4 has been studied in the temperature range 175$^{\circ}C$ to 575$^{\circ}C$ for both quenched and annealed specimens. The strain ageing in quenched Zircaloy-4 was found in the temperature range 175$^{\circ}C$ to 50$0^{\circ}C$ and its Peak occured at 3$25^{\circ}C$ while the strain ageing in annealed specimens occured in the temperature range 175-575$^{\circ}C$, showing two peaks, one at 323$^{\circ}C$ and a higher one at 45$0^{\circ}C$. The peak at 3$25^{\circ}C$ in both quenched and annealed specimens is considered to be due to the segregation of interstitial oxygen atoms to cell walls during ageing. The peak at 45$0^{\circ}C$ in annealed specimens is considered to he due to the interaction of dislocations with Fe atoms. It has been found that strain ageing stress at ~30$0^{\circ}C$ in zirconium alloys is proportional to the square root of oxygen content.

• Journal of Electrochemical Science and Technology
• /
• v.3 no.4
• /
• pp.185-189
• /
• 2012

A.c. impedances of mechanically polished CP-Ti specimens were measured at open-circuit potential (OCP) with immersion time and under applied anodic potentials between -0.2 and 1 $V_{Ag/AgCl}$ in 0.1 M NaOH solution. Capacitances of native oxide films ($C_{ox,na}$) grown naturally and capacitances of anodic oxide films ($C_{ox,an}$) formed under applied anodic potentials were obtained to examine the growth of native and anodic oxide films in 0.1 M NaOH solution and how to use $C_{ox,na}$ for the surface area measurement of Ti specimen. $1/C_{ox,na}$ and $1/C_{ox,an}$ appeared to be linearly proportional to OCP and applied potential ($E_{app}$), with proportional constants of 0.086 and 0.051 $uF^{-1}\;V^{-1}$, respectively. The $C_{ox,na}$ also appeared to be linearly proportional to geometric surface area of the mechanically polished CP-Ti fixture specimen, with proportional constants of 11.3 and $8.5{\mu}F\;cm^{-2}$ at -0.45 $V_{Ag/AgCl}$ and -0.25 $V_{Ag/AgCl}$ of OCPs, respectively, in 0.1 M NaOH solution. This linear relationship between $C_{ox,na}$ and surface area is suggested to be applicable for the measurement of real surface area of Ti specimen.

• Journal of the Korean Ceramic Society
• /
• v.36 no.9
• /
• pp.901-908
• /
• 1999

Effects of LPMOCVD process parameters on the properties of TiO2 thin film were investigated. Depositions were made in the range of temperature 300-67$0^{\circ}C$ with various TTIP(Titanium Tetraisopropoxide) concentrations by contrlling bubbler temperature(40-8$0^{\circ}C$) and/or flow rate(30-90 sccm). Post annealing treatments were carried out at 500-80$0^{\circ}C$ range in the air. Films deposited at 40$0^{\circ}C$ have denser morphology than those of films deposited at 50$0^{\circ}C$ and $600^{\circ}C$ due to slower deposition rate. Bubbler temperature can affect on the deposition rate in mass transfer controlled regime such as 50$0^{\circ}C$ or higher but not below 50$0^{\circ}C$ where surface reaction rate becomes important. On the contrary for films deposited above 50$0^{\circ}C$ flow rate can raise deposition rate but eventually saturate it at the 50 sccm and above due to retarded adhesion of decomposed species. But for films deposited at 40$0^{\circ}C$ deposition rate increases stadily with flow rate. As the film becomes more porous A(200) texture can not be developed and AnataselongrightarrowRutile transition kinetics increases.

• The Korean Journal of Zoology
• /
• v.32 no.3
• /
• pp.242-251
• /
• 1989

Morphometric and genetic analyses on six populations of the two subspecies of Cobitis koreensis were performed to investigate the geographic variation and to clarify their taxonomic status. No significant differences between subspecies were found. Puan population of C. k. pumilus tends to be smaller in numbers of cross bars and dorsal spots, than those of C. k. koreensis populations with no statistical significance. Average degree of genic variation among six populations of the two subspecies was A=1.5, P =37.3%, HD=0.053, and HG=0.097. Marginal populations of Samchog (C. k. koreensis) and Puan(C. k. pumilus) were least variable: A= 1.3, P=23.8%, HD=0.0l0, HG=0.043, and A= 1.2, P=19.0%, HD=0.029, HG=0.078 respectively.The difference between HD and HG in all populations may indicate a patchness distribution between demes within each population. Genetic similarities between the two subspecies were, on the average, S=0.894, and this value correspond to the average genetic similarities among five populations of C. k. koreensis (5=0.899). Chongup population of C. k. koreensis and Puan population of C. k. pumilus was most similar genetically (5 =0.931). The results of morphometric and genetic analysis in this study indicate that C. k. pumilus is not a valid subspecies and should be considered as a population of C. koreensis.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.36 no.5
• /
• pp.589-594
• /
• 2007

The effect of synergists having chelating ability on inhibiting browning were studied with a giucose-glutamic acid model for doenjang containing citric acid as the anti-browning agent and iron ion. The model solutions were prepared by dissolving 0.1 M glucose, 0.1 M glutamic acid, 50 mM citric acid, 0.2 mM $FeCl_2$ and synergist in 1 M phosphate buffer (pH 7.0), heating at $50^{\circ}C$ for 24 hr and storing at $30^{\circ}C\;or\;40^{\circ}C$ for four weeks. Synergists were chitosan, gallic acid, methyl benzoate, pyrophosphate and tannic acid; they were used at the following concentrations: gallic acid, pyrophosphate and tannic acid at 0.015% and 0.15%; chitosan and methyl benzoate at 0.0075% and 0.015%. Anti-browning capacities had a tendency to decrease greatly after three weeks in the case of storage at $30^{\circ}C$, whereas they decreased with storage time during storage at $40^{\circ}C$. However, anti-browning capacities of samples containing 0.015% tannic acid and 0.15% pyrophosphate were higher than that of sample without synergist by 32% after storage at $30^{\circ}C$ for four weeks. Gallic acid, tannic acid and pyrophsphate also inhibited the formation of Maillard reaction intermediates such as fluorescent compound and 3-deoxyglucosone due to the high chelating ability with iron ion after four weeks of storage at $30^{\circ}C$. The effect of these compounds on the inhibition of formation of Maillard reaction intermediates was higher at 0.15% than at 0.015%. Moreover, gallic acid increased the browning by forming colored complexes, and tannic acid generated black precipitates. Therefore, pyrophosphate of food additives was found to be the most useful synergist of citric acid, the anti-browning agent for doenjang.

• Korean Journal of Materials Research
• /
• v.7 no.3
• /
• pp.180-187
• /
• 1997

$La_{0.68}Ca_{0.32}Cr_{0.97}O_{3}$ interconnector films ior pimar rypn solid oxide fuel (,ells were prepared under various sinteririg conditions and their bending strength. relative ilerisit~. m t l c:lec ~ ~ - i i ; i l condl~cti\.lt\ were niexiureti in order to study their mechanical and electrical propertics Th' Irndirig sriength of $La_{0.68}Ca_{0.32}Cr_{0.97}O_{3}$ lt the room temperature \vas increased with increasing sinrering temperature dnfl tinic. The relative densit\- of more than 94% was ohtained 1)). sintering at $1400^{\circ}C$ for 5hrs. The present irlvestigiition rovcals thcit sirileririg of $La_{0.68}Ca_{0.32}Cr_{0.97}O_{3}$ at lorn. temperature xyvas greatly assisted by formation oi Ca,,,(CrO,),, Also the i,leitriczl conductivity at $1000^{\circ}C$ \vas more than 100S; cm d t e r heating at $1400^{\circ}C$ for 7hrs.

• The Korean Journal of Malacology
• /
• v.19 no.2
• /
• pp.133-142
• /
• 2003

For the effective seedling production of flat oyster, Ostrea denselamellosa, dietary value of live food, densities, water temperature and salinity on growth and survival rate of the larvae were examined. In rearing larvae by feeding them phytoplankton diets, the optimal survival rate and growth rate of larvae were found using a mixed phytoplankton diet which was mixed with Isochrysis galbana, Chaetoceros calcitrans and Chlorella sp. The highest growth and survival rates of the larvae were 208.4% and 38.8% with the phytoplankton diet. In growth and survival rates of larvae with various rearing densities, the highest survival and growth rates were 228.1% and 29.0% at the density of 2 individuals/ml. In observing rearing experiments of the flat oyster larvae under various temperature conditions, average growth rates of the larvae in respect to shell length were 202.2%, 240.4%, 250.6% and 121.3% in natural water temperatures (18-22$^{\circ}C$), 24$^{\circ}C$, 28$^{\circ}C$ and 32 $^{\circ}C$, respectively. And average survival rates of the larvae were 16.0%, 32.0%, 13.0% and 0% in natural water temperatures (18-22$^{\circ}C$), 24$^{\circ}C$, 28$^{\circ}C$ and 32$^{\circ}C$, respectively. In rearing at various salinities, the highest growth rates of the larvae in shell length was 240.0% at 30.0 psu and the highest survival rate was 31.0% at 25 psu.

• Journal of Life Science
• /
• v.15 no.6 s.73
• /
• pp.972-978
• /
• 2005

The present study was carried out to investigate the blood markers of Jeju horses. The redcell cypes (blood groups) and blood protein types (biochemical polymorphisms) were tested from 102 Jeju horses by serological and electrophoretc procedure, and their phenotypes and gene frequencies were estimated. The blood group and biochemical polymorphism phenotypes observed with high frequency were $A^{af}\;(27.45\%$), $C^{a}\;(99.02\%$), $K^{-}\;(97.06\%$), $U^{a}\;(62.75\%$), $P^{b}\;(36.27\%$), $Q^{c}\;(47.06\%$), $D^{cgm/dghm}\;(13.73\%$), $D^{adn/cgm}\;(9.80\%$), $D^{ad/cgm}$\;(8.82\%$), $D^{dghm/dghm}(7.84\%$), $D^{cgm/cgm}(7.84\%$), $AL^{B}\;(48.04\%$), $GC^{F}\;(99.02\%$), $AlB^{K}\;(97.06\%$), $ES^{FI}\;(36.27\%$), $TF^{F2}\;(25.49\%$), $HB^{B1}\;(45.10\%$), and $PGD^{F}\;(86.27\%$) in Jeju horses, respectively. Alleles observed with high gene frequency were $A^{af}$ (0.3726), $A^{C}$ (0.2647), $C^{-}$ (0.5050), $K^{-}$ (0.9853), $U^{-}$ (0.6863), $P^{b}$ (0.4657), $Q^{c}$ (0.5294), $D^{cgm}$ (0.3039), $HB^{B1}$(0.6863), $PGD^{F}$ (0.9265), $AL^{B}$ (0.6912), $ALB^{K}$ (0.9852), $GC^{F}$ (0.9950), $ES^{I}$ (0.5000) and $TF^{F2}$ (0.4950) in Jeju horses, and sfecific alleles, $D^{cgm(f)}$ (0.0196), $HB^{A}$ (0.0147), $HB^{A2}$ (0.0196), $ES^{G}$ (0.0441), $ES^{H}$ (0.0098), $TF^{E}$TF'(0.0246), $TF^{H2}$ (0.0049) and $PGD^{D}$ (0.0098) were detected in Jeju horses. These preliminary results present basic information for detecting the genetic markers in Jeju horse. and developing a system for parentage verification and individuals identification in jeju horses.