The ductile-brittle transition behavior of two austenitic Fe-18Cr-10Mn-N-C alloys with different grain sizes was investigated in this study. The alloys exhibited a ductile-brittle transition behavior because of an unusual brittle fracture at low temperatures unlike conventional austenitic alloys. The alloy specimens with a smaller grain size had a higher yield and tensile strengths than those with a larger grain size due to grain refinement strengthening. However, a decrease in the grain size deteriorated the low-temperature toughness by increasing the ductile-brittle transition temperature because nitrogen or carbon could enhance the effectiveness of the grain boundaries to overcome the thermal energy. It could be explained by the temperature dependence of the yield stress based on low-temperature tensile tests. In order to improve both the strength and toughness of austenitic Fe-Cr-Mn-N-C alloys with different chemical compositions and grain sizes, more systematic studies are required to understand the effect of the grain size on the mechanical properties in relation to the temperature sensitivity of yield and fracture stresses.

TiO2 nanowires were grown by thermal oxidation of TiO powder in an oxygen and nitrogen gas environment at 1000 oC. The ratio of O2 to N2 in an ambient gas was changed to investigate the effect of the gas ratio on the growth of TiO2 nanowires. The oxidation process was carried out at different O2/N2 ratios of 0/100, 25/75, 50/50 and 100/0. No nanowires were formed at O2/N2 ratios of less than 25/75. When the O2/N2 ratio was 50/50, nanowires started to form. As the gas ratio increased to 100/0, the diameter and length of the nanowires increased. The X-ray diffraction pattern showed that the nanowires were TiO2 with a rutile crystallographic structure. In the XRD pattern, no peaks from the anatase and brookite structures of TiO2 were observed. The diameter of the nanowires decreased along the growth direction, and no catalytic particles were detected at the tips of the nanowires which suggests that the nanowires were grown with a vapor-solid growth mechanism.

The small brown planthopper (SBPH), Laodelphax striatellus Fallén (Hemiptera: Delphacidae) is one of the major insect pest against rice, Oryza sativa L. in Korea. High density of SBPH could cause severe damage on rice plant by directly sucking and indirectly transmitting viral pathogens, Rice stripe virus and Rice streaked dwarf virus. As a preliminary study for de novo whole-genome sequencing of SBPH, we investigated 6 transcriptomes isolated from different developmental stages, sex, and tissue (egg, 1st ~ 3rd nymphs, 4th ~ 5th nymphs, female and male adults, salivary gland). Clean-sequence data of 19.3 Gb were obtained from total 47.8 Gb raw data after adaptor and quality trimming (Q30) and overlapped reads joining. As a suitable assembler, Bridger was selected based on the results of reference mapping (93.45%) and CEGMA completeness (95.97%). Finally, we obtained 158,207 reads (size range: 201 ~ 22,162 bp; Mean size: 1,048.04 bp; N50: 2,417 bp) after clustering the assembly results by CD-HIT-EST (similarity threshold: 99%). Based on these results, we are conducting further studies such as transcript expression pattern among different developmental stages and gene annotation.

Galaxy clusters, the largest gravitationally bound systems, are an important subject of study to place constraints on cosmological models. Moreover, they are excellent places to test galaxy evolution models in connection to their environments. To date, massive clusters have been found unexpectedly (Kang & Im 2009; Gonzales et al. 2012) and the evolution of galaxies in clusters is still controversial (Elbaz et al. 2007; Faloon et al. 2013). Finding galaxy cluster candidates at z > 1 in a wide, deep imaging survey data will enable us to solve such issues of modern extragalactic astronomy. We report new candidate galaxy clusters in one of the wide and deep survey fields, the European Large Area ISO Survey North1 (ELAIS-N1) and North2 (ELAIS-N2) fields, covering a sky area of 8.75 deg2 and 4.85 deg2 each. We also suggest a new useful color selection technique to separate z > 1 galaxies from low - z galaxies by combining multi-wavelength data.

n-Butanol and ethyl acetate extracts of thermal treatment yam (Dioscorea batatas DECNE.) belonging to the family Dioscoreaceae were measured for their radical scavenging activity and lipid peroxidation inhibition ability. In this study, ethyl acetate extract showed the most potent antioxidant activity evaluated by ferrous ion chelating activity and NO radical scavenging activity. Nevertheless, n-butanol extract was more effective in inhibiting linoleic acid peroxidation. A significant difference between n-butanol extract and ethyl acetate extract in nitrite scavenging activity β-carotene bleaching assays could not be found. Also, the results of this study showed that thermal treatment yam could be used as easily accessible source of natural antioxidants and as a possible food supplement.

Nitrogen (N) loading from domestic, agricultural and industrial sources can lead to excessive growth of macrophytes or phytoplankton in aquatic environment. Many studies have used nitrogen stable isotope ratios to identify anthropogenic nitrogen in aquatic systems as a useful method for studying nitrogen cycle. In this study to evaluate the precision and accuracy of Kjeldahl processes, two reference materials (IAEA-NO-3, N-1) were analyzed repeatedly. Measured the δ¹⁵N-NO₃and δ¹⁵N-NH₄values of IAEA-NO-3 and IAEA-N-1 were 4.7±0.2‰ and 0.4±0.3‰, respectively, which are within recommended values of analytical uncertainties. Also, we investigated spatial patterns of δ¹⁵N-NO₃and δ¹⁵N-NH₄in effluent plumes from a waste water treatment plant in Han River, Korea. δ¹⁵N-NO₃and δ¹⁵N-NH₄values are enriched at downstream areas of water treatment plant suggesting that dissolved nitrogen in effluent plumes should be one of the main N sources in those areas. The current study clarifies the reliability of Kjeldahl analytical method and the usefulness of stable isotopic techniques to trace the contamination source of dissolved nitrogen such as nitrate and ammonia.

Bi2Te3 related compounds show the best thermoelectric properties at room temperature. However, n-type Bi2Te2.7Se0.3 showed no improvement on ZT values. To improve the thermolectric propterties of n-type Bi2Te2.7Se0.3, this research has Cu-doped n-type powder. This study focused on effects of Cu-doping method on the thermoelectric properties of n-type materials, and evaluated the comparison between the Cu chemical and mechanical doping. The synthesized powder was manufactured by the spark plasma sintering(SPS). The thermoelectric properties of the sintered body were evaluated by measuring their Seebeck coefficient, electrical resistivity, thermal conductivity, and hall coefficient. An introduction of a small amount of Cu reduced the thermal conductivity and improved the electrical properties with Seebeck coefficient. The authors provided the optimal concentration of Cu0.1Bi1.99Se0.3Te2.7. A figure of merit (ZT) value of 1.22 was obtained for Cu0.1Bi1.9Se0.3Te2.7 at 373K by Cu chemical doping, which was obviously higher than those of Cu0.1Bi1.9Se0.3Te2.7 at 373K by Cu mechanical doping (ZT=0.56) and Cu-free Bi2Se0.3Te2.7 (ZT=0.51).

N-propyl-N,N-dimethylethanolamine의 산란혼탁매질에서 형광, 산란과 응집의 영향은 파장과 산란된 형광세기로 나타내는데, laser induced fluorescence(LIF) 분광학에 의한 분자특성으로 나타난다. 산란매질에서 광학적 효과는 광학적 파라미터들(μs, μa, μt)에 의해 표현되고 응집은 고-액상 분리공정에서 중요하게 활용되고 있다. 따라서 입자가 서로 접근될 때 콜로이드 입자들의 상호작용을 LIF와 응집효과로 분석하였다. Monte Carlo simuation과 실험으로 레이저 광원에서 검출기까지 거리의 함수에 의해 농도가 묽어짐에 따라 산란세기가 기하급수적으로 감소함을 알 수 있었다. 이는 유지화학, 생의학, 레이저 의학, 의공학 분야적용에 LIF와 입자이동 현상은 아주 적합한 모델 연구에 큰 도움이 될 것이다.

In this study, n-butanol and ethyl acetate extracts were prepared from raw yam (Dioscorea batatas DECNE.). Their antioxidative potencies were investigated employing various in vitro methods, such as ferrous ion chelating, β-carotene bleaching assay, lipid peroxidation inhibition and nitric oxide (NO) radical scavenging and nitrite scavenging activity. The n-butanol fraction was assayed to possess stronger antioxidant activity by β-carotene bleaching assay, lipid peroxidation inhibition and NO radical scavenging activity. However, ethyl acetate extract was more effective in chelating ferrous ion and scavenging nitrite. Based on the results obtained, yam is a potential active ingredient that could be applied in antioxidation as well as bio-health functional food to take a good part in prevention of human diseases and aging.

In order to understand Xǔ Shèn’s 許慎 contribution to the analysis of the Chinese writing system, it is important to clarify the terminology he uses in his Shuōwén jiězì 說文解字 (100 AD). In this paper I shall focus on the term shěng 省. Scholars who have studied the problem of shěng 省 in Shuōwén usually tried to reveal the mistakes either made by Xǔ Shèn or added later to the text, from different perspectives including the classification of the graphs in traditional liùshū approach, paleography, as well as phonological reconstructions. i Most of these authors may be right in their critical investigation of shěng 省, there are indeed many mistakes in Xǔ Shèn’s graphic analysis, but none of them considered the problem as a whole or tried to understand what was the real reason for Xǔ Shèn to use this term. Shěng 省is a rather complex term with different significations, such as ommission, abbreviation, fusion, etc. I shall first clarify the meanings and uses of shěng in Shuōwén, before trying to understand why Xǔ Shèn needed this special term. We will see that despite many mistaken graphic analysis, already described by Chēn Shìhuī 陳世輝 (1979), Qiú Xīguī 裘錫圭 (1988), and others, shěng 省was an important tool for Xǔ Shèn’s methodological approach to the Chinese writing system that also shows his deep knowledge of the evolution of the script.

NF3 기체는 반도체, 디스플레이 산업에서 cleaning 또는 etching 가스로 많이 이용되고 있다. 6대 온실가스에 속하지는 않으나 차기 온실가스로 지구온난화지 수도 이산화 탄소에 비해 17200배 높다. 최근 NF3를 분리 농축 회수에 있어서 고분자 분리막, 복합막등의 다양한 연구가 이루어지고 있다. 하지만 실제 공정설계, 공정 최적화를 이루기 위한 분리특성의 연구가 미비한 상태이다. 이에 따라 본 연구에서는 NF3와 N2, O2의 온도와 압력에 따른 투과특성을 확인하고, 혼합기체에서의 주입농도와 Stage-cut에 따른 농축농도와 회수율에 대하여 연구하였다.

NF3 가스는 반도체산업 공정에서 클리닝과 에천트로서 사용되는 고가의 불소기반가스로써 높은 지구 온난화지수를 가지고 있다. 현재 국내에서 NF3 가스는 N2와 혼합된 형태로 추가 정제 과정 없이 대기 중으로 배출된다. 따라서 환경보호 및 높은 부가가치를 위해서 분리·정제를 통한 NF3 가스 재사용이 필요하다. 본 연구에서는 글리세롤과 아세톤을 첨가하여 NF3 분리용 Polysulfone 중공사막의 기공형태 변화를 관찰하였다. 그리고 PDMS, PTMSP, AF 등의 고분자를 지지체 표면에 농도별로 코팅하여 N2/NF3 투과성능을 비교하였다. PDMS, PTMSP, AF를 코팅한 중공사막에서 투과도는 각각 1.94, 6.79, 6.86 GPU를 나타냈고 선택도는 5.10, 2.53, 6.12로 측정되었다.

본 연구는 N2/NF3 분리를 위해 다양한 상업용 고분자를 이용하여 최초로 실증적 N2/NF3 분리상한선을 정의하였고, 6FDA–DAM:DABA(3:2), Teflons AF 2400, PTMSP가 가장 우수한 분리성능을 보여주었다. 또한, Freeman이론에 기반한 이론적 N2/NF3 상한선을 결정하였고, 이를 통해 실증적 상한선의 타당성을 증명하였다. 마지막으로, N2/NF3 분리성능 향상을 위해, Matrimid® 5218에 ZIF-8을 혼합한 하이브리드 분리막을 개발하였다. 용매, 입자크기 및 리간드가 하이브리드 분리막의 N2/NF3 분리성능에 미치는 영향을 연구하였다.

PTMSP에 0∼50 wt% NaA Zeolite를 첨가하여 PTMSP-NaA Zeolite 복합막을 제조하고, PTMSP-NaA Zeolite 복합막의 특성을 FT-IR, 1H-NMR, GPC, DSC, TGA, SEM에 의해서 조사하였다. PTMSP-NaA Zeolite 복합막의 수소와 질소에 대한 투과도와 선택성을 NaA Zeolite 함량에 따라 조사하였다. TGA측정에 의하면 PTMSP에 NaA Zeolite가 첨가되었을 때 복합막의 감량이 완결되는 온도는 낮아졌고, 감량(wt%)도 작아졌다. SEM관찰에 의하면 NaA Zeolite는 PTMSP-NaA Zeolite 복합막 내에 2∼5 μm 크기로 분산되어 있었다. PTMSP-NaA Zeolite 복합막에 대한 N2와 H2의 투과도는 NaA Zeolite 함량이 증가하면 증가하였다. 그리고 PTMSP-NaA Zeolite 복합막의 N2에 대한 H2의 선택성은 NaA Zeolite함량이 증가하면 감소하였다.

The N-Screen contents is a kind of emerging technologies to make a new user-experience by integrating multiple devices like smart TVs, personal computers, and smartphones. In the paper, we characterize game design issues of N-Screen based game with smart TV and smartphone and describe the game design issues of 「Beaver Rising」as its case study.「Beaver Rising」is the N-Screen game which developed by our team ans its' game play is similar with a classic game, called「Snake」but it can be played on a smart TV screen while players can control their own beaver characters with their smartphones. We first give a survey of N-Screen games to characterize their properties in the paper. Then, we describe the game play, game design architecture, and user experience of the game,「Beaver Rising」as its case study. Finally, we propose three new properties to make an effective N-screen game with a smart TV and smartphons. The paper will contribute to provide am effective game design guideline when we make a N-screen based game with a smart TV and smartphones.