• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.345-345
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• 2012

최근 의료산업에서는 고해상도 및 동영상 구현이 가능한 직접 방식의 X-선 검측센서에서 X-ray 흡수효율이 좋은 반도체 센서(CdTe, CdZnTe 등)와 성숙된 기술, 집적효율이 뛰어난 CMOS 공정을 이용한 제품을 출시하여 대면적화 및 고집적화가 가능하게 되어 응용분야가 점차 확대되고 있는 추세이다. 하지만 이 역시 고 성능의 X-선 동영상 구현을 위해서는 고 해상도 문제, 검출효율 문제, 대면적화의 어려움이 있다. 기존의 X-선 광 도전층의 증착은 증착 속도와 박막 품질에서 우수한 Evaporation 법이 사용되고 있다. 한편, 대면적에 균일한 박막형성이 가능하기 때문에 양산성에서 우월성을 가지는 sputtering법의 경우, 밀도가 높은 소결체 타겟의 제조가 힘들뿐만 아니라 증착 속도가 낮아 장시간 증착 시 낮은 소결밀도로 인한 타겟 Particle 영향으로 인해서 대 면적에 고품질의 박막을 형성하기가 어렵다. 하지만 최근 소결체 타겟 제조기술 발달과 함께, 대면적화와 장시간 증착에 대한 어려움이 해결되고 있어 sputtering 법을 이용한 고품질 박막 제조 기술의 연구가 시급한 실정이다. 본 연구에서는 $50{\times}50$ mm 크기의 non-alkali 유리기판(Corning E2000) 위에 Evaporation과 RF magnetron sputtering을 사용하여 다양한 기판온도 (RT, 100, 200, 300, $350^{\circ}C$)에서 $1{\mu}m$의 두께로 CdTe 박막을 증착하였다. RF magnetron sputtering의 경우 CdTe 단일 타겟(50：50 at%)을 사용하였으며 Base pressure는 약 $5{\times}10^{-6}$ Torr 이하까지 배기하였고, Working pressure는 약 $7.5{\times}10^{-3}$ Torr에서 증착하였다. 시편과 기판 사이의 거리는 70 mm이며 RF 파워는 150 W로 유지하였다. CdTe 박막의 미세구조는 X-ray diffraction (XRD, BRUKER GADDS) 및 Field Emission Scanning Electron Microscopy (FE-SEM, Hitachi)를 사용하여 측정하였다. 또한, 조건별 박막의 조성은 Energy Dispersive X-ray Spectroscopy (EDS, Horiba, 7395-H)을 사용하여 평가하였다. X-선 동영상 장치의 구현을 위해서는 CdTe 다결정 박막의 높은 흡수효율, 전하수집효율 및 SNR (Signal to Noise Ratio) 등의 물성이 요구된다. 이러한 물성을 나타내기 위해서는 CdTe 박막의 높은 결정성이 중요하다. Evaporation과 RF magnetron sputtering로 제작된 CdTe 박막은 공정 온도가 증가함에 따라 기판상에 도달하는 스퍼터 원자의 에너지 증가로 인해서 결정립이 성장한 것을 확인할 수 있었다. 따라서 CdTe 박막이 직접변환방식 고감도 X-ray 검출기 광도 전층 역할을 수행할 수 있을 것으로 기대된다.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.58.1-58.1
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• 2010

In solar cell module manufacturing, single solar cells has to be joined electrically to strings. Copper stripes coated with tin-silver-copper alloy are joined on screen printed silver of solar cells which is called busbar. The bus bar collects the electrons generated in solar cell and it is connected to the next cell in the conventional module manufacturing by a metal stringer using conventional hot air or infrared lamp soldering systems. For thin solar cells, both soldering methods have disadvantages, which heats up the whole cell to high temperatures. Because of the different thermal expansion coefficient, mechanical stresses are induced in the solar cell. Recently, the trend of solar cell is toward thinner thickness below 180um and thus the risk of breakage of solar cells is increasing. This has led to the demand for new joining processes with high productivity and reduced error rates. In our project, we have developed a new method to solder solar cells with a laser heating source. The soldering process using diode laser with wavelength of 980nm was examined. The diode laser used has a maximum power of 60W and a scanner system is used to solder dimension of 6" solar cell and the beam travel speed is optimized. For clamping copper stripe to solar cell, zirconia(ZrO)coated iron pin-spring system is used to clamp both joining parts during a scanner system is traveled. The hot plate temperature that solar cell is positioned during lasersoldering process is optimized. Also, conventional solder joints after $180^{\circ}C$ peel tests are compared to the laser soldering methods. Microstructures in welded zone shows that the diffusion zone between solar cell and metal stripes is better formed than inIR soldering method. It is analyzed that the laser solder joints show no damages to the silicon wafer and no cracks beneath the contact. Peel strength between 4N and 5N are measured, with much shorter joining time than IR solder joints and it is shown that the use of laser soldering reduced the degree of bending of solar cell much less than IR soldering.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.5-5
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• 2009

Thin-film-transistors (TFTs) that can be prepared at low temperatures have attracted much attention because of the great potential for transparent and flexible electronics. One of the mainstreams in this field is the use of organic semiconductors such as pentacene. But device performance of the organic TFTs is still limited due to low field-effect mobility and rapid degradation after exposing to air. Alternative approach is the use of amorphous oxide semiconductors as a channel. Amorphous oxide semiconductors (AOSs) based TFTs showed the fast technological development, because AOS films can be fabricated at room temperature and exhibit the possibility in application like flexible display, electronic paper, and larges solar cells. Among the various AOSs, a-IGZO has lots of advantages because it has high channel mobility, uniform surface roughness and good transparency. [1] The high mobility is attributed to the overlap of spherical s-orbital of the heavy post-transition metal cations. This study demonstrated the effect of the variation in channel thickness from 30nm to 200nm on the TFT device performance. When the thickness was increased, turn-on voltage and subthreshold swing was decreased. The a-IGZO channels and source/drain metals were deposited with shadow mask. The a-IGZO channel layer was deposited on $SiO_2$/p-Si substrates by RF magnetron sputtering, where RF power is 150W. And working pressure is 3m Torr, at $O_2/Ar$ (2/28 sccm) atmosphere. The electrodes were formed with electron-beam evaporated Ti (30 nm) and Au (70 nm) bilayer. Finally, Al (150nm) as a gate metal was thermal-evaporated. TFT devices were heat-treated in a furnace at 250 $^{\circ}C$ and nitrogen atmosphere for 1hour. The electrical properties of the TFTs were measured using a probe-station. The TFT with channel thickness of 150nm exhibits a good subthreshold swing (SS) of 0.72 V/decade and on-off ratio of $1{\times}10^8$. The field effect mobility and threshold voltage were evaluated as 7.2 and 8 V, respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.12
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• pp.1761-1768
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• 2005

Effects of alpha-galactosidase (GAL) on broiler corn-soybean meal diet was investigated. In experiment 1, sixty cockerels were allocated to five groups, including three enzyme treatments (GAL added at 0, 500, and 1,000 mg/kg diet), a nitrogen-free diet group and a fast group. The true nitrogen-corrected ME (TME$_n$) and true amino acid availability were determined. In experiment 2, 324 day-old chicks were used in a 2${\times}$3 factorial design consisting of two energy contents (high and low) and three GAL levels (0, 250, and 500 mg/kg). Three feeding phases, comprising 0-21 d, 22-35 d and 36-48 d, were involved. GAL addition improved TME$_n$ and the availability of methionine and cystine (p<0.05). The apparent ME (AME) or nitrogen-corrected AME (AME$_n$) and digestibility of dry matter, organic matter, calcium, and phosphorus were improved significantly on d 21, so was crude protein and an interaction of energy and GAL on AME$_n$ (p<0.05) was found on d 35. However, daily intake and daily gain were significantly improved with GAL addition (p<0.05) during 21 d. The small intestine relative weight decreased at 250 mg/kg GAL (p<0.05) on d 35, whereas presented an interaction between GAL and energy on d 21 (p<0.05). Likewise, this treatment increased breast muscle ratio (p<0.05). On d 21, triglycerides level of broilers showed interaction between energy and enzyme levels (p<0.05). Uric acid level in 500 mg/kg GAL declined linearly (p<0.05). On d 35, quadratic effects (p<0.05) were observed in total protein, albumin, globulin and cholesterol content for enzyme supplementation. And the interactive effects of energy and GAL on serum values showed more obviously. The study implies that GAL improved energy and nutrient availability of corn-soybean meal diet in broiler. The GAL supplementation to corn-soybean meal based diet can improve performance of broilers in early stages of growth.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.4
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• pp.481-488
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• 2003

Insulin-like Growth Factors (IGFs) and IGF-binding protein act as intra-ovarian regulators that modulate the proliferation and differentiation of the granulosa and theca cells. Moreover, the IGF system is involved in metabolism by modulating the synthesis and degradation of glycogen and protein in animals. However the effect of the IGF system on egg productivity or body growth in KNOC has not been studied in depth. Therefore, this study was performed to investigate differences of serum IGFs and binding protein expressions between two groups showing high and low egg production or body weight and to elucidate the relationship of IGFs with egg productivity and body growth. KNOCs were divided into high and low groups depending on their egg productivity or body growth, and sera were collected every 10 wk from 20 till 60 wk. Serum IGF-I and -II concentration were measured by RIA using human and mouse antiserum and chicken standards. IGFBP was detected by Western ligand blotting. IGF-I concentrations were significantly greater in the high egg production group compared with those in the low egg production group (30 wk, p<0.01; 20 and 40 wk, p<0.05). Also, differences in IGF-II amounts between the two groups were detected at 60 wk (p<0.05). But IGFBPs in the low egg production group were more intense than that in the high egg production group through the egg laying period. The correlation between IGF-I concentration and number of egg production is significantly positive (20 wk, r=0.2729: p<0.05; 40 wk, r=0.3500: p<0.01), while IGF-II shows no correlation with egg productivity. In male KNOC, IGF-I and -II concentrations in the high body weight group are lower than that in the low body weight group. Body weight also shows a negative correlation with the serum IGF-II concentration in male chickens (20 wk, r=-0.5901: p<0.01). Consequently, we suggest that IGFs and binding protein are (in)directly involved in the egg productivity and body growth in KNOC.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.4
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• pp.551-560
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• 2014

Twenty-four male 1-year old swamp buffaloes (Bubalus bubalis) were randomly allocated to 4 groups. One group grazed on guinea grass (GG) and another on guinea grass and the legume Stylosanthes guianensis (GL). The other two groups were kept in pens and fed freshly cut guinea grass and concentrate at an amount of 1.5% (GC1.5) and 2.0% (GC2.0) of body weight, respectively. The effect of the different feeding intensities on carcass characteristics and meat quality were assessed. The mean body weight at slaughter was 398 (${\pm}16$) kg. Average daily gain was higher in concentrate-supplemented groups (570 and 540 g/d in GC1.5 and GC2.0, respectively) when compared to GG (316 g/d) and GL (354 g/d) (p<0.01). Likewise, the warm carcass weight was higher in GC1.5 and GC2.0 compared to GG and GL. Dressing percentage was 48.1% and 49.5% in GC1.5 and GC2.0 in comparison to 42.9% and 44.8% observed in GG and GL, respectively. Meat of Longissimus throracis from GC1.5 and GC2.0 was redder in color (p<0.01), while water holding capacity (drip and thawing loss) was improved in pasture-fed groups (p<0.05). Protein and fat content of Longissimus thoracis was higher in animals supplemented with concentrate (p<0.01), as was cholesterol content (p<0.05), whereas PUFA:SFA ratio was higher and n-6/n-3 ratio lower (p<0.01) in pasture-fed buffaloes. Results of the present study showed that the supplementation of pasture with concentrate enhances the growth and carcass characteristics of swamp buffaloes expressed in superior dressing percentage, better muscling, and redder meat with a higher content of protein and fat, whereas animals grazing only on pasture had a more favorable fatty acid profile and water holding capacity. In conclusion, the supplementation of concentrate at a rate of about 1.5% of body weight is recommended to improve the performance and carcass quality of buffaloes.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.4
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• pp.471-477
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• 2008

The porcine PRKAG3 (RN) gene encodes the regulatory gamma subunit of adenosine monophosphate-activated protein kinase (AMPK), which is a good candidate gene affecting meat quality. In this study, the effects of two missense mutations A595G (Ile199Val) and G154A (Gly52Ser) in porcine PRKAG3 gene on meat quality traits were studied in M. Longissimus dorsi (LD), M. Semispinalis capitis (SC) and M. Biceps femoris (BF) from different populations of 326 pigs. The PRKAG3 alleles 199I, 199IV, 52S and 52G were identified with PCR-RFLPs and all genotypes - 199I/199I, 199I/199V, 199V/199V, 52S/52S, 52S/52G and 52G/52G - were found. The frequency of V allele was larger than that of I allele in all populations. I allele frequency was zero in Chinese Meishan pigs (population D) especially. G allele frequency was larger than that of S allele in all populations except Large White (population A). Both variations at the PRKAG3 locus significantly affected these meat quality traits. The pork meat quality has not previously been established in Meishan or crosses thereof. The results suggested that generally pH of LD, SC and BF was higher in Meishan pigs than that in other populations. Moreover, Meishan pigs showed higher water-holding capacity and intramuscular fat (IMF), lower water content and water loss percentage compared to other populations in terms of the two variations. The results present here supply new evidence that alleles V199I and G52S at the PRKAG3 locus affect pork meat quality and provide useful information on pork production.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.10
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• pp.1512-1518
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• 2015

This experiment was conducted to assess the welfare and productivity of gestating gilts in groups with the electronic sow feeding (ESF) system compared to conventional stalls. A total of 83 gilts ($Yorkshire{\times}Landrace$) were housed into individual stalls to be artificially inseminated. Gilts confirmed pregnant were introduced to their treatment, conventional stalls (ST) or groups with the ESF system. All gilts were taken to the farrowing crates one week prior to their expected farrowing date. In the gestation period, there were no significant differences between gilts allocated to ST and ESF on growth performance. However, backfat thickness gain (p = 0.08) and body condition score (BCS) at 110 days of gestation (p = 0.10) tended to be higher in ESF gilts than ST. Likewise, gilts housed in group showed significantly higher estimated body muscle contents at 110 days of gestation (p = 0.02) and body muscle change during gestation (p = 0.01). There was a trend for a shorter parturition time in ESF gilts (p = 0.07). In the lactation period, group housed gilts showed a tendency to increased BCS changes (p = 0.06). Reproductive performance did not differ with the exception of piglet mortality (ST = 0.2 no. of piglets vs ESF = 0.4 no. of piglets; p = 0.01). In blood profiles, ST gilts showed a higher cortisol level at 110 days of gestation (p = 0.01). Weaning to estrus interval was shorter in gilts housed in ESF than ST (p = 0.01). In locomotory behaviors, ESF gilts recorded a tendency to elevate locomotion score at 36, 70, and 110 days of gestation (p = 0.07, p = 0.06, and p = 0.06, respectively). Similarly, ESF gilts showed significantly higher incidence of scratches at 36, 70, and 110 days of gestation (p = 0.01). Moreover, farrowing rates were higher in stall treatment (97.6%) compare to group housing treatment (95.2%). In conclusion, while group housed gilts with ESF system positively affected welfare status in combination with less physiologically stressful environments and activity, it negatively effects piglet mortality, farrowing rates and injuries of gilts.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.3
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• pp.292-301
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• 2010

Follicle-stimulating hormone (FSH) is a pituitary glycoprotein hormone that is encoded by separate alpha- and betasubunit genes. It plays a key role in stimulating and regulating ovarian follicular development and egg production in chicken. FSH signal transduction is mediated by the FSH receptor (FSHR) that exclusively interacts with the beta-subunit of FSH, but characterization of prokaryotic expression of the FSHb gene and its effect on the expression of the FSHR gene in local chickens have received very little attention. In the current study, the cDNA fragment of the FSHb gene from Dagu chicken was amplified using reverse transcription polymerase chain reaction (RT-PCR), and inserted into the pET-28a (+) vector to construct the pET-28a-FSHb plasmid. After expression of the plasmid in E. coli BL21 (DE3) under inducing conditions, the recombination protein, $FSH{\beta}$ subunit, was purified and injected into the experimental hens and the effect on the mRNA expression levels of the FSHR gene was investigated. Sequence comparison showed that the coding region of the FSHb gene in the local chicken shared 99%-100% homology to published nucleotides in chickens; only one synonymous nucleotide substitution was detected in the region. The encoded amino acids were completely identical with the reported sequence, which confirmed that the sequences of the chicken FSHb gene and the peptides of the $FSH{\beta}$ subunit are highly conserved. This may be due to the critical role of the normal function of the FSHb gene in hormonal specificity and regulation of reproduction. The results of gene expression revealed that a recombinant protein with a molecular weight of about 19 kDa was efficiently expressed and it was identified by Western blotting analysis. After administration of the purified $FSH{\beta}$ protein, significantly higher expression levels were demonstrated in uterus, ovary and oviduct samples (p<0.05). These observations suggested that the expressed $FSH{\beta}$ protein possesses biological activity, and has a potential role in regulation of reproductive physiology in chickens.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.6
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• pp.781-790
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• 2011

The effects of seedtime and maturity stage on nutritive value of five maize stover varieties, including conventional maize (Kexiangyu 11, CM), fodder maize (Huqing 1, FM), high oil maize (Gaoyou 115, HOM), sweet maize (Kexiangtianyu 1, SM) and waxy maize (Kexiangluoyu 1, WM), were examined based on chemical composition, in vitro gas production and in situ incubation techniques. Maize stover was sampled at d 17 and d 30 after tasseling, and designated as maturity stage 1 and stage 2, respectively. The average dry matter (DM) organic matter (OM), crude protein (CP) and fiber contents were the greatest for HOM, SM and FM, respectively. CM had the highest in vitro organic matter disappearance (IVOMD) and volatile fatty acid (VFA) concentration. The highest ammonia nitrogen ($NH_3$-N) concentration in the incubation solution, and effective degradability of DM ($ED_{DM}$) and neutral detergent fiber ($ED_{NDF}$) were observed in SM. Advanced maturity stage increased (p<0.05) DM content, $ED_{DM}$ and $ED_{NDF}$, but decreased (p<0.05) OM and CP contents, and decreased (p<0.05) b and a+b values, IVOMD and molar proportion of valerate in the incubation solution for maize stover. Maize sown in summer had greater (p<0.05) OM content, but lower DM, CP, neutral detergent fiber (NDF) and acid detergent fiber (ADF) content compared with maize sown in spring. Maize sown in summer had greater (p<0.001) IVOMD, $NH_3$-N concentration in the incubation solution and $ED_{NDF}$, but lower (p<0.01) ratio of acetate to propionate compared to maize sown in spring. The interaction effect of variety${\times}$seedtime was observed running through almost all chemical composition, in vitro gas production parameters and in situ DM and NDF degradability. The overall results suggested that SM had the highest nutrient quality, and also indicated the possibility of selecting maize variety and seedtime for the utilization of maize stover in ruminants.