• Journal of Embryo Transfer
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• v.21 no.4
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• pp.331-338
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• 2006

This survey was carried out to investigate the occurrence of reproductive disorders in Korean native cattle (Hanwoo). The general management status such as barn type, feed intake, parity and type of reproductive disorders were examined in the Hanwoo farms. In this survey, the total incidence of reproductive disorders that was assessed from 54 Hanwoo farms was 11.6% (73/ 631). We first examined the incidence of reproductive disorders following herd size per farm. The rates of reproductive disorders in under 10 heads, 10 to 20 heads and over 20 heads were 25.2%, 9.4% and 8.3%, respectively (P<0.05). The rate of reproductive disorders in tie stall barn was significantly (P<0.05) higher than that in free stall barn (14.9% vs. 8.1%). The major types of reproductive disorders were follicular cysts (21.8%), fat necrosis (21.8%), and repeat breeding (17.8%). The rate of reproductive disorders assessed by the parity tended to decrease as the parity increased. The relationship between incidence of reproductive disorders and body condition score (BCS) was investigated in 203 Hanwoo. The incidence of reproductive disorder was 80.0%, 8.8%, 9.4%, 10.0%, 33.3% and 57.1% at 1.5, 2.0, 2.5, 3.0, 3.5 and 4.0 of BCS, respectively. These data show that the increase of herd size, barn type and BCS affect the incidence of reproductive disorders such as follicular cysts, fat necrosis and repeat breeding in Hanwoo.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.107-108
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• 2008

The spectacular development of AMLCDs, been made possible by a-Si:H technology, still faces two major drawbacks due to the intrinsic structure of a-Si:H, namely a low mobility and most important a shift of the transfer characteristics of the TFTs when submitted to bias stress. This has lead to strong research in the crystallization of a-Si:H films by laser and furnace annealing to produce polycrystalline silicon TFTs. While these devices show improved mobility and stability, they suffer from uniformity over large areas and increased cost. In the last decade we have focused on microcrystalline silicon (${\mu}c$-Si:H) for bottom gate TFTs, which can hopefully meet all the requirements for mass production of large area AMOLED displays [1,2]. In this presentation we will focus on the transfer of a deposition process based on the use of $SiF_4$-Ar-$H_2$ mixtures from a small area research laboratory reactor into an industrial gen 1 AKT reactor. We will first discuss on the optimization of the process conditions leading to fully crystallized films without any amorphous incubation layer, suitable for bottom gate TFTS, as well as on the use of plasma diagnostics to increase the deposition rate up to 0.5 nm/s [3]. The use of silicon nanocrystals appears as an elegant way to circumvent the opposite requirements of a high deposition rate and a fully crystallized interface [4]. The optimized process conditions are transferred to large area substrates in an industrial environment, on which some process adjustment was required to reproduce the material properties achieved in the laboratory scale reactor. For optimized process conditions, the homogeneity of the optical and electronic properties of the ${\mu}c$-Si:H films deposited on $300{\times}400\;mm$ substrates was checked by a set of complementary techniques. Spectroscopic ellipsometry, Raman spectroscopy, dark conductivity, time resolved microwave conductivity and hydrogen evolution measurements allowed demonstrating an excellent homogeneity in the structure and transport properties of the films. On the basis of these results, optimized process conditions were applied to TFTs, for which both bottom gate and top gate structures were studied aiming to achieve characteristics suitable for driving AMOLED displays. Results on the homogeneity of the TFT characteristics over the large area substrates and stability will be presented, as well as their application as a backplane for an AMOLED display.

• Journal of Embryo Transfer
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• v.19 no.3
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• pp.219-227
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• 2004

This study was conducted to develop a serum-free, defined medium of IVM of pig oocytes. The TCM-199 with supplemented with polyvinylalcohol(PVA), polyvinylpyrrollidone(PVP) and porcine follicular fluid(pFF) were used as basal medium. The effects of the these additives on the rates of maturity and development under in-vitro fertilization and in vitro culture were examined and subsequently considered on the possibilities be sustituted for the bovine serum albumin(BSA). Maturation rate of pig oocytes in IVM media containing PVA(82.4％), pFF(89.4％) and BSA(90.0％) were significantly higher(P<0.05) than that of PVP(78.6％). Cleavage rate after IVF of PVP(64％) was significantly lower(P<0.05) than these of PVA(73％), pFF(77％) and BSA(73％) supplements. in vitro development rates to morulae and blastocyst on PVP(54％) were also significantly lower(P<0.05) than these of the supplements of PVA(63％), pFF(69％) and BSA(65％). In comparison of maturation and fertilization rates of pig oocytes in each supplements, the maturity rates of PVA(82.4％), pFF(89.4％) and BSA(90.0％) were significantly lower(P<0.05) than that of PVP(72.4％) and while, the fertilization rates of pFF(87.1％) and BSA(89.1％) were significantly higher(P<0.05) than these of PVA(78.0％) and PVP(70.6％). It may be concluded that PVA and pFF can be substituted far BSA in medium for culturing pig oocytes; however, it may be considered that PVP were limited to for BSA in the in vitro culture of the embryos.

• Journal of Embryo Transfer
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• v.18 no.2
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• pp.115-124
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• 2003

The objective of this study was to compare the effect of four different estrus induction methods in anestrus cows on the estrus induction and pregnancy following artificial insemination (AI). Sixty-five cows (3∼4 years old) were selected and divided into four different estrus induction treatment groups. Group 1, 12 cows were treated by Ovsynch program combined with GnRH and PGF$_2$a. Group 2, 12 cows were treated by "Tow plus Two" program with GnRH and PGF$_2$a. Group 3, 20 cows were treated by "Tow plus Two" program following intravaginal progesterone implantation (CIDR). Twenty one cows in Group 4 were treated by "Tow plus Two" program following follicular rupture and intravaginal progesterone implantation. Cows were then observed estrus induction and inseminated artificially at 12 h and 24 h after standing estrus. The rates of estrus induction in Group 4 (18/21, 86%) was significantly (P<0.05) higher than those in groups 1, 2 and 3 (8/12, 67%; 9/12, 75%; 14/20, 70%). In the mean time of onset of estrus after final administration of GnRH in different hormone-treated cows, the cows in Group 3 (24.2$\pm$2.2) and Group 4 (23.4$\pm$2.0) were significantly (P<0.05) shorter than that in Group 1 (28.5$\pm$4.6) and Group 2 (26.4$\pm$3.3). The rates of pregnancy diagnosed on Day 28 were significantly different between treatment groups. Significantly (P<0.05) higher rate of pregnancy was observed in Group 4 (17/20, 85.0%) than those in Groups 1, 2 and 3 (7/11, 63.6%; 8/12, 66.7%; 15/20, 75.0%, respectetively). The rate of abortion diagnosed on 49 days of gestation was significantly (P<0/05) lower in Group 4 (1/17, 5.9%) than those in Groups 1, 2 and 3 (2/7, 28.7%; 2/8, 25% and 3/15, 20%, respectively). In conclusion, combined treatments with GnRH and PGF$_2$a following follicular rupture and progesterone implant in anestrus cows was considered to be most effective in estrus induction and maintenance of pregnancy. Further studies are needed to verify the functional mechanisms of residual follicles in anestrus ovaries on retarding the response of hormonal treatments.sponse of hormonal treatments.

• Journal of Embryo Transfer
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• v.28 no.1
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• pp.19-24
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• 2013

This study assesses of efficiency of oocyte recovery and in vitro development for during the non breeding season in goat. Thirty-four matured goats, maintained in a pen under natural day length and fed hay ad libitum, were pretreated with progestagen implanted CIDR for 10 days. Superovulation treatment of the goats received twice daily intramuscular injections of a total of 70 mg FSH for 3 days from Day 8 of CIDR. All the gonadotropin treated goats were injected with 10 mg $PGF_2{\alpha}$ on Day 8 and 400~600 IU hCG in the afternoon on Day 10. Oocytes were recovered by follicle aspiration or oviduct flushing at 35 to 40 h after hCG injection through mid-ventral incision. The in vivo matured oocytes were activated by ionomycin (5 min) and 6-DMAP (3.5~4 h). The activated oocytes were cultured in mSOF medium containing 0.8% BSA at $38.5^{\circ}C$ in an atmosphere of 5% $CO_2$, 5% $O_2$, 90% $N_2$ for 7~8 days. There was no significant difference in the mean number of CL and in vivo matured and follicular oocytes recovered. But, quality of I+II grade follicular oocytes was lower (p<0.05) in the prepubertal goat (25.0%) than the adults (52.4%). The same results were also observed in the cleavage and blastocyst rate of activated oocytes. The clavage and blastocyst rate from prepubertal derived oocytes were lower (p<0.05) in the prepubertal goat (54.5%, 23.3%) than the adult goat (86.8%, 46.6%). Considering overall these results, we suggest that maturation of donor goats is a major factor affecting recovered oocytes quality and in vitro development of activated goat oocytes. There was no significant difference in oocyte quality between seasonal treatments.

• Journal of Wetlands Research
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• v.16 no.4
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• pp.379-388
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• 2014

A sewage was treated using a serially combined vertical(VFCW) and horizontal flow double media (sand and zeolite for VFCW and sand and waste oyster-shell for HFCW) reed constructed wetland(HFCW) with intermittent feeding (see Fig. 1). The sewage was fed into the reed constructed wetland for 10 minutes every 6 hours at the hydraulic load of $314L/m^2{\cdot}day$. The summarized results were as follows: pH values in the effluent depended very heavily on oyster-shell height filled in the HFCW. They were maintained at less than pH 6.24 when the height of the oyster-shell layer was 200 mm. Influent DO(oxygen demand) values(average 0.19 mg/L) were increased in the VFCW(average 7.65 mg/L) and decreased again in the HFCW(average 6.49 mg/L). They were higher in the winter than in the summer. The OTR(oxygen transfer rate) was $57.15g\;O_2/m^2{\cdot}day$ in the VFCW and $5.65g\;O_2/m^2{\cdot}day$ in the HFCW. The removal efficiency of $NH_4{^+}$-N was 80.17%(6.01 $NH_4{^+}$-N mg/L in the effluent). It was lower than that in the case where only zeolite was filled in the reed constructed wetland. But it was expected that treated sewage effluent using a double media reed constructed wetland with 300 mm zeolite layer could stably meet the Korean treated sewage effluent standard(20 mg T-N/L). Average removal efficiencies were SS 88.09%, BOD 88.12%, $COD_{Cr}$ 83.11%, $COD_{Mn}$ 85.58%, T-N 57.21%, $NH_4{^+}$-N 80.17%, T-P 86.73%. Nearly, The concentration of $NO_3{^-}$-N in the effluent of the VFCW was decreased in that of the HFCW. More than half of T-N in the effluent was $NO_3{^-}$-N(7.92 mg/L) but the concentration of $NO_2{^-}$-N in the effluent was average 0.90 mg/L. The removal efficiencies of T-P were 93.24%, 86.30% and 55.44% at the height of the oyster-shell-filled constructed wetland of 800 mm, 500 mm and 200 mm, respectively and therefore, they were proportional to oyster-shell height filled in the HFCW.

• Reproductive and Developmental Biology
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• v.31 no.3
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• pp.199-205
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• 2007

The present study was carried out to assess the effect of superovulation response and efficiency of embryo production induced with injection of FSH dissolved in polyethylene glycol (PEG) in Hanwoo. Eighty-eight cows were divided into four groups. In group 1, cattle were intramuscularly treated with twice-daily administration of 50mg FSH for 4 days. Group 2 and 3 were subcutaneously single injection of 400mg and 200mg FSH dissolved in 30% PEG, respectively. Group 4 were subcutaneously single injection of 200 mg FSH dissolved in 30% PEG at 7 day after CIDR insertion. The number of corpus luteum (CL) in group 2 resulted in significantly (p<0.05) higher compared to group 1, 3 and 4 (18.5 vs. 11.2, 13.1 and 13.9, respectively). However, the number of total ova $(7.9{\sim}10.4)$, transferable embryos $(3.7{\sim}4.7)$, degenerate embryos $(1.9{\sim}3.5)$ and unfertilized ova $(1.8{\sim}2.7)$ did not differ among treatment groups. No difference was observed in pregnancy rate after transferring the recovered embryos among groups $(36.0{\sim}50.0%)$. In addition, blood progesterone concentrations at embryo recovery did not differ among all groups. In conclusion, although no differences were observed in the number of total ova, transferable embryos and pregnancy rate after transfer, a single injection of reduced dose of FSH (200mg FSH) at 7 day after CIDR insertion is more practical for superovulation treatments than frequent injection because of reduction of stress in Hanwoo and decreases of cost and laber.

• Journal of Embryo Transfer
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• v.18 no.1
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• pp.61-68
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• 2003

Considerable attention has been focused on the cryopreservation of semen and estrus induction in dog, as consequence of poor productivity caused by long anestrus period, in order to enhance the productivity of youngs and to preserve the breeds. The objectives of this study were to improve reproductive efficiency of artificial insemination with fresh- and frozen-semen following estrus induction in dog. Fifty infertilie dogs (age 2~3 years) were selected fur the study and divided into three different estrus induction treatment groups. Group 1 : dogs (n=15) were given clomifene (0.1 mg/kg) orally f3r five days at 12 hr intervals. Croup 2: dogs (n=15) were given bromocriptine (50 $\mu$g/kg) orally for five days at 12 hr intervals, followed by single injection intravenously of 500 IU GnRH (Croup 3, n=20) when pro-estrus occurred. After being treated, the dogs were evaluated fur the rates of estrus induction and time interval lapses from treatment to beginning of the pro-estrus. The rates of pregnancy in estrus inducted dogs mated naturally compared to those inseminated artificially with ejaculated fresh semen and frozen-thawed semen. Estrus detection was performed using the method of vaginal smear and confirmed by the plasma progesterone assay. Pregnancy was confirmed by ultrasonograpy on day 25, 35 and 55 post insemination. The ejaculated semen was exposed to a mixture of Tris extender with cryoprotectant (Trisma, 81 mM; TES, 209 mM; citric acid, 6 mM; glucose, 5 mM; glycerol, 8%) and cryopreserved gradually by slow-cooling at 17 co above the surface of liquid nitrogen (L$N_2$) for 23 min. The use of fresh semen, the pregnancy rates were observed 66.6, 66.6, 75.0 and 83.3% in natural estrus, clomifene induced, bromocriptine induced and a combination of GnRH and bromocriptine, respectively. The use of frozen-thawed semen, the pregnancy rates were observed 66.6, 33.3, 50.0 and 60.0% in natural estrus, clomifene induced, bromocriptine induced and a combination of GnRH and bromocriptine, respectively. No difference was observed in the number of offspring produced among natural estrus and treated groups inseminated with fresh or frozen-thawed semen. In conclusion, there was no significant differences in the pregnancy rate of dogs between group treated with a combination of GnRH and bromocriptine and group treated clomifene or bromocriptine only. However, frozen-thawed semen can be used successfully fur artificial insemination in dog.

• The Journal of the Convergence on Culture Technology
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• v.8 no.6
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• pp.927-933
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• 2022

We synthesized (C₁₀H₈N₂H)₂Cr₂O₇, The structure of the product was characterized with FT-IR(infrared) and elemental analysis. The oxidation of benzyl alcohol by (C₁₀H₈N₂H)₂Cr₂O₇ in organic solvents showed that the reactivity increased with the increase of the dielectric constant. The oxidation of alcohols was examined by (C₁₀H₈N₂H)₂Cr₂O₇ in DMF, acetone. As a resuit, (C₁₀H₈N₂H)₂Cr₂O₇ was found as efficicent oxidizing agent that converted benzyl alcohol, allyl alcohol, primary alcohol and secondary alcohols to the corresponding aldehydes or ketones(65%~95%). The selective oxidation of alcohols was also examined by (C₁₀H₈N₂H)₂Cr₂O₇ in DMF, acetone. (C₁₀H₈N₂H)₂Cr₂O₇ was selective oxidizing agent(15%~95%) of benzyl alcohol, allyl alcohol and primary alcohol in the presence of secondary ones. In the presence of DMF solvent with acidic catalyst such as H₂SO₄. (C₁₀H₈N₂H)₂Cr₂O₇ oxidized benzyl alcohol(H) and its derivatives. The Hammett reaction constant(ρ) was -0.69(308K). The observed experimental data were used to rationalize the hydride ion transfer in the rate determining step.

• Composites Research
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• v.31 no.2
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• pp.43-50
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• 2018

The effects of deposition temperature on chemical vapor deposited silicon carbide (CVD-SiC) were studied to obtain high deposition rates and excellent bending strength characteristics. Silicon carbide prepared at $1250{\sim}1400^{\circ}C$ using methyltrichlorosilane(MTS : $CH_3SiCl_3$) by hot-wall CVD showed deposition rates of $95.7{\sim}117.2{\mu}m/hr$. The rate-limiting reaction showed the surface reaction at less than $1300^{\circ}C$, and the mass transfer dominant region at higher temperature. The activation energies calculated by Arrhenius plot were 11.26 kcal/mole and 4.47 kcal/mole, respectively. The surface morphology by the deposition temperature changed from $1250^{\circ}C$ pebble to $1300^{\circ}C$ facet structure and multi-facet structure at above $1350^{\circ}C$. The cross sectional microstructures were columnar at below $1300^{\circ}C$ and isometric at above $1350^{\circ}C$. The crystal phases were all identified as ${\beta}$-SiC, but (220) peak was observed from $1300^{\circ}C$ or higher at $1250^{\circ}C$ (111) and completely changed to (220) at $1400^{\circ}C$. The bending strength showed the maximum value at $1350^{\circ}C$ as densification increased at high temperatures and the microstructure changed from columnar to isometric. On the other hand, at $1400^{\circ}C$, the increasing of grain size and the direction of crystal growth were completely changed from (111) to (220), which is the closest packing face, so the bending strength value seems to have decreased.