Fe-TiC composite was fabricated from Fe and TiC powders by high-energy milling and subsequent spark- plasma sintering. The microstructure, particle size and phase of Fe-TiC composite powders were investigated by field emission scanning electron microscopy and X-ray diffraction to evaluate the effect of milling conditions on the size and distribution of TiC particles in Fe matrix. TiC particle size decreased with milling time. The average TiC particle size of 38 nm was obtained after 60 minutes of milling at 1000 rpm. Prepared Fe-TiC powder mixture was densified by spark- plasma sintering. Sintered Fe-TiC compacts showed a relative density of 91.7~96.2%. The average TiC particle size of 150 nm was observed from the FE-SEM image. The microstructure, densification behavior, Vickers hardness, and frac- ture toughness of Fe-TiC sintered compact were investigated.

We present a multi-dimensional reduction method of the surveyed cube database obtained using a single- dish radio telescope in Taeduk Radio Astronomy Observatory (TRAO). The multibeam receiver system installed at the 14 m telescope in TRAO was not optimized at the initial stage, though it became more stabilized in the following season. We conducted a Galactic Plane survey using the multibeam receiver system. We show that the noise level of the first part of the survey was higher than expected, and a special reduction process seemed to be definitely required. Along with a brief review of classical methods, a multi-dimensional method of reduction is introduced; It is found that the ‘background’ task within IRAF (Image Reduction and Analysis Facility) can be applied to all three directions of the cube database. Various statistics of reduction results is tested using several IRAF tasks. The rms value of raw survey data is 0.241 K, and after primitive baseline subtraction and elimination of bad channel sections, the rms value turned out to be 0.210 K. After the one-dimensional reduction using ‘background’ task, the rms value is estimated to be 0.176 K. The average rms of the final reduced image is 0.137 K. Thus, the image quality is found to be improved about 43% using the new reduction method.

In this study, the potential possibility of biodiesel fuel was investigated as an alternative fuel for a naturally aspirated common rail diesel engine. The smoke emission of biodiesel fuel 30 vol%(max. content) was reduced in comparison with diesel fuel, that is, it was reduced approximately 60% at 4000rpm, full load. But, power, torque and brake specific energy consumption didn't have no large differences. But, NOx emission of biodiesel fuel was increased compared with commercial diesel fuel.

파나마의 농경지는 전체 국토면적 74,340 km2의 약 30%에 해당하는 22,300 km2이다. 파나마 전체인구 3,508천명의 약 25%에 해당하는 사람들이 농촌에 거주하고 있으며, 총 취업인구에서 농업부문이 차지하는 취업자 비중은 17.6%수준이다. 경제발전에 따라 전체 GDP에서 농업부문이 차지하는 비중은1995년 10.5%에서 2010년 4.6%로 감소하고 있으나 농식품수출이 파나마 전체 상품수출에서 차지하는 비중은 75%로 매우 높은 수준이다. 주요 수출 농산물은 멜론, 수박, 바나나, 파인애플 등 열대과일이다. 이들 주요 수출품이 전체 농산물 수출에서 차지하는 비중은 20%이상으로 높은 수준이며, 열대과일 수출의 90%이상이 유럽연합과 북아메리카지역의 소수 국가에 집중되어 수출되고 있다. 또한 파나마의 전략 수출 농산물인 열대과일은 주로 부가가치가 낮은 신선상태로 수출 중으로 연도별 수출도 안정적이지 못한 상황이다. 우선 아시아 신흥시장 등 다른 수출유망 지역과 국가로 수출선이 다변화되지않은 이유는 첫째, 긴 수송거리로 인한 운송비 등 유통비용문제, 둘째, 콜드체인시스템 등 저장유통기술과 표준화 부족으로 인한 고품질 유지의 어려움, 셋째, 달러가치의 상승으로 인한 수출경쟁력 저하, 넷째, 고부가가치 상품개발 미흡과 식품가공산업의 미발달 등이다. 파나마의 기후 등 농업환경을 고려할 때 열대과일은 생산력 증진과 지속적 품질 향상을 통해수출경쟁력 제고가 가능하고 수출산업화가 가능한 분야이다. 하지만 파나마가 이들 품목을 한국, 일본, 중국 등 동북아시아주요 수출시장에 수출하기 위해서는 무엇보다 해외시장 개척을 위한 더 많은 정책적 노력이 필요하다. 특히 파나마 정부가 성공적으로 파나마산 열대과일을 동북아시아 시장에 수출하기 위해서는 이들 대표적인 수출 품목을 안정적으로 해외시장에 수출할 수 있는 수출단지 육성을 적극적으로 고려하고,이들 품목과 단지를 중심으로 해외마케팅이나 수출지원 프로그램을 집중화해 나갈 필요가 있다.

The reactive oxygen species (ROS) generated during the somatic cell transfer nuclear (SCNT) procedures may cause the mitochondrial dysfunction and DNA damage, which may result in restricts the reprogramming of SCNT embryos and play a key direct role in apoptosis. The present study was conducted to investigate the effect of antioxidant treatment during the SCNT procedures on the inhibition of mitochondria and DNA damages in bovine SCNT embryos. The reconstituted oocytes were treated with antioxidants of 25 μM β-mercaptoethanol (β-ME) or 50 μM vitamin C (Vit. C) during the SCNT procedures. In vitro fertilization (IVF) was performed for controls. Mitochondrial morphology and membrane potential (ΔΨ) were evaluated by staining the embryos with MitoTracker Red or JC-1. Apoptosis was analyzed by Caspase-3 activity assay and TUNEL assay, and DNA fragmentation was measured by comet assay at the zygote stage. Mitochondrial morphology of non-treated SCNT embryos was diffused within cytoplasm without forming clumps, while the IVF embryos and antioxidant treated SCNT embryos were formed clumps. The ΔΨ of β-ME (1.3±0.1, red/green) and Vit. C-treated (1.4±0.2, red/green) SCNT embryos were significantly higher (p<0.05) than that of non-treated SCNT embryos (0.9±0.1, red/ green), which similar to that of IVF embryos (1.3±0.1, red/green). Caspase-3 activity was not difference among the groups. TUNEL assay also revealed that little apoptosis was occurred in SCNT embryos as well as IVF embryos regardless of antioxidant treatment. Comet tail lengths of β-ME and Vit. C-treated SCNT embryos (337.8±23.5 μm and 318.7 ±27.0 μm, respectively) were shorter than that of non-treated SCNT embryos (397.4± 21.4 μm) and similar to IVF embryos (323.3±10.6 μm). These results suggest that antioxidant treatment during SCNT procedures can inhibit the mitochondrial and DNA damages of bovine SCNT embryos.

Cryopreservation of canine spermatozoa affords potential exchange of genetic material, and thus may lead to improvement in the breeding management. However, canine spermatozoa undergo many damages such as, cold shock, ice crystal formation, oxidative stress during cryopreservation. In this study used the CASA for investigating the effect of various trehalose concentrations and thawing temperatures on the sperm viability. In addition, the efficacy of the most optimal of the tested cryopreservation protocols in this study was verified by AI as the in vivo test. Also, this study evaluates the variation of frozen- thawed canine spermatozoa during different incubation condition. The addition of trehalose 25 mM was optimal concentration and frozen-thawed semen quality was significantly higher better than control (Glucose) and other concentration groups. In effect of thawing temperature on frozen-thawed sperm movement and intact acrosome evaluations, which result enhance the sperm motility and movement value depending on increase temperature condition at 36, 54 and 72℃. Also, in the effect of different incubation condition on frozen-thawed sperm after thawing at 36℃ for 60 sec, that the results trehalose 25 mM was significantly better (p<0.05) than glucose in general as well as, the post-thawed sperm motility and intact acrosome was reduced depending on increase the incubation time. Especially, incubation at 4 to 8 hour was rapidly depreciation of movement value and the rate of intact acrosome was dropped similar tendency. Thus, incubation 17℃ was better than other incubation groups on sperm motility and acrosome integrity. For the in vivo evaluate of spermatozoa survival and is the most definitive test of sperm function, we performed artificial insemination in estrous bitch. The semen was prepared for intrauterine insemination using the 25 mM trehalose freezing extender and thawing at 36℃, and 2 bitches were inseminated with 1×106 motile spermatozoa by surgical method. The results of AI, the pregnancy rates, mean litter size and oocyte fertilization rate were 16.6% (1/6), and 50% (2/4), respectively. In conclusion, based on the results of these experiments, the effect of addition of trehalose on extender improves the movement and intact acrosome of frozen-thawed semen. In particular, trehalose 25 mM groups was higher than other different concentration group on movement value and acrosome integrity of frozen-thawed sperm. Also, through incubation condition, this study identify the optimal incubation temperature after thawing was 17℃. Furthermore, the information will be contributed to develop the canine ART including AI, IVF and canine ICSI. * This research was supported by iPET (Grants 110056-3), Ministry for Food, Agriculture, Forestry and Fisheries, Republic of Korea.