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        검색결과 2,998

        1781.
        2010.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to find out the effects of artificial shrinkage (AS) on post-thaw development of bovine embryos. The blastocoelic cavity of blastocyst was punctured to remove its fluid contents and then incubated in the holding medium (HM) for 10 min. The punctured and non-punctured (control) blastocysts were equilibrated in vitrification solution 1 (VS1; TCM-199+20% FBS+10% EG) for 5 min and vitrification solution 2 (VS2; TCM199+20% FBS+35% EG+5% PVP+0.5 M Sucrose) for 1 min and vitrified by direct dropping into the liquid nitrogen. Vitrified blastocysts (punctured and control) were thawed and cultured in vitro (12 hr) for studying survival and hatching rates. The levels of shrinkage were measured by the volume of the blastocyst during equilibration in VS1 (at 1, 3 and 5 min of equilibration) and VS2 (at 30 and 60 sec of equilibration) that was considering the volume of non-punctured blastocyst in HM as 100%. The levels of shrinkage were higher in punctured group (62.4, 64.6, 64.3% at 1, 3 and 5 min in VS1; 50.6 and 52.7% at 30 and 60 sec in VS2) than control group (84.8, 86.6, 86.4% at 1, 3 and 5 min in VS1; 72.1 and 68.8% at 30 and 60 sec in VS2), but within each group the levels of shrinkage were similar. The survival (90.9%) and hatching (50.0%) rates of vitrified blastocysts at 12 hr post-thaw were higher in punctured group than that in control group (76.9% and 0.0% respectively). We confirmed that vitrification solutions (VS1 and VS2) have no toxic effect on the survival of blastocysts because the survival rates of blastocysts exposed to VS1 and VS2 for 24 hr were similar between punctured and control groups (94.3 vs. 96.0%; p>0.05). In conclusion, the preliminary data show that AS of blastocyst may improve survival and hatching rate after thawing.
        4,000원
        1782.
        2010.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this paper we examined the association of Infrared Dark Cloud (IRDC) cores with YSOs and the geometric properties of the IRDC cores. For this study a total of 13,650 IRDC cores were collected mainly from the catalogs of the IRDC cores published from other studies and partially from our catalog of IRDC cores containing new 789 IRDC core candidates. The YSO candidates were searched for using the GLIMPSE, MSX, and IRAS point sources by the shape of their SED or using activity of water or methanol maser. The association of the IRDC cores with these YSOs was checked by their line-of-sight coincidence within the dimension of the IRDC core. This work found that a total of 4,110 IRDC cores have YSO candidates while 9,540 IRDC cores have no indication of the existence of YSOs. Considering the 12,200 IRDC cores within the GLIMPSE survey region for which the YSO candidates were determined with better sensitivity, we found that 4,098 IRDC cores (34%) have at least one YSO candidate and 1,072 cores among them seem to have embedded YSOs, while the rest 8,102 (66%) have no YSO candidate. Therefore, the ratio of [N(IRDC core with protostars)]/[N(IRDC core without YSO)] for 12,200 IRDC cores is about 0.13. Taking into account this ratio and typical lifetime of high-mass embedded YSOs, we suggest that the IRDC cores would spend about 104~105 수식 이미지 years to form high-mass stars. However, we should note that the GLIMPSE point sources have a minimum detectable luminosity of about 1.2 L⊙ at a typical IRDC core's distance of ~4 kpc. Therefore, the ratio given here should be a 100ver limit and the estimated lifetime of starless IRDC cores can be an upper limit. The physical parameters of the IRDC cores somewhat vary depending on how many YSO candidates the IRDC cores contain. The IRDC cores with more YSOs tend to be larger, more elongated, and have better darkness contrast than the IRDC cores with fewer or no YSOs.
        4,800원
        1783.
        2010.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Yttria stabilized zirconia (Y-CSZ) single crystals show plastic deformation at high temperatures byactivating dislocations. The effect of strain rate on the plastic behavior of this crystal was studied. As increasingstrain rate from ε=1.04×10-5sec-1 to 2.08×10-5sec-1 the yield drop was suppressed and resulted in higherYoung's modulus and yield stress. Dislocation structures of the strained crystals were analyzed using atransmission electron microscope to elucidate the plastic behavior of these crystals. In the early stage of plasticdeformation, dislocation dipoles and prismatic dislocation loops were formed in both samples. However,dislocation density was increased by increasing strain rate. Strong sessile dislocations were observed in thesample with higher strain rate, which may cause the higher work hardening.
        4,000원
        1784.
        2009.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Yttria stabilized zirconia single crystals show plastic deformation at high temperatures by activating dislocations. The plastic deformation is highly dependent on crystallographic orientation. When the samples were deformed at different orientations, stress-strain curves changed by operating different slip systems. The strength of samples was also highly dependent on crystallographic orientation, i.e., samples without yield drop showed higher strength than that of samples exhibiting yield drop. The slip systems in the sample deformed along<112>,<111> and<001> agreed with the theoretical values of the plastic deformation, following Schmid's Law. Dislocations play a major role in the plastic deformation of this crystal. At the early stages of plastic deformation, all samples exhibited dislocation dipoles and, in the later stages, dislocation interactions occurred by forming nodes, tangles and networks. In this study, three different orientations, [11-2], [111] and [001] were employed to explain the plastic deformation behavior. A microstructural analysis was performed to elucidate the mechanism of the plastic behavior of this crystal.
        4,000원
        1785.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The principal objective of this study was to analyze Swede’s perceptions of Asian food using a means-end chain method, which may contribute to our understanding of new markets for a food industry interested in globalizing Korean food. With the Means-end chain method, one can determine the cognitive structures built in consumer’s minds, which are developed by connecting attributes of product, consequences, and values. The attributes of Asian food that are most positively perceived by Swedes are ‘fresh vegetables’, ‘low-fat’, ‘light meat and seafood’, ‘exotic ingredients’, ‘not expensive’ and ‘unknown food’. The consequences of eating Asian food connected to these attributes are ‘healthy’, ‘tasty’, ‘good way to save money’ and ‘curious’. Finally, Swedes expect to enjoy a value of ‘achievement’ at the end. Based on the result that ‘unknown food’ attribute is connected to ‘achievement’ value, Swedes are assumed to be attracted by the fact that Korean food is ‘unknown food’. However, the effect of the ‘unknown food’ attribute will fade away with time; therefore, stressing Korean food’s status as a ‘healthy’ food, which can be attributed to its use of ‘fresh vegetable’ and ‘light meat and seafood’ ingredients and ‘low fat’ cooking method may be effective as a long-term strategy for making Korean food attractive. The ‘healthy’ consequence is connected to Swedes’ perception of the value ‘achievement’ and simultaneously to their perception of the value ‘belonging and love/sense of belonging’.
        4,000원
        1786.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Dahi is yoghurt like fermented dairy products available in Bangladesh made by traditional ways from raw milk. The aim of the present study was to check and compare the present quality status of the market dahi in reference to laboratory made dahi. For this, dahi was prepared in the laboratory (A) and collected from Kishoregonj district (B), Gazipur district (C), Bogra district (D) and Dhaka district (E and F). Consumer acceptance quality was judged on 100 point by a judge panel and chemical and microbiological quality test were done by established methods. ‘A’ type dahi was superior followed by E, D, F, B and C considering the consumer acceptance quality parameter. From chemical test, it appears that, B possess the lowest pH (3.75 ± 0.05) and highest was in C (4.46 ± 0.15). Total solids content of F type dahi (318.40 ± 4.44 g/kg) was highest and fat (52.00 ± 2.00 g/kg), protein (44.33 ± 2.00 g/kg) and ash (10.76 ± 0.31 g/kg) content were also higher in F type dahi. E and A type dahi were also with considerable figure in chemical quality parameter. Dahi B was inferior in respect of microbiological quality- total viable count (TVC) (× 105 cfu/ml) content was 94.00 ± 4.58, yeast (cfu/ml) content was 183.33 ± 15.28 and mold (cfu/ml) content was 53.33 ± 15.28. The TVC (× 105 cfu/ml), yeast (cfu/ml) and mold (cfu/ml) content of A type dahi were 39.67 ± 4.51, 50.00 ± 10.00 and 20.00 ± 10.00, respectively. Considering all the three major quality aspects dahi A was superior than others followed by F, D, E, C and B.
        4,000원
        1787.
        2009.12 구독 인증기관 무료, 개인회원 유료
        본 연구는 신흥 글로벌 대학교로써 필리핀 대학의 가상 캠퍼스이자 5번째 구성 단위인 필리핀 개방대학(UPOU)을 중심으로 지식기반 시대의 평생교육에 관한 새로운 경향에 대해 조사한 연구이다.필리핀 개방대학(UPOU)의 경험을 기반으로 본다면, 평생 학습은 본래 온라인 학습의 영향을받을 것임이 분명하다. 새로운 시대의 온라인 학습은 확장적이며 학습자 중심이 될 것이다. 그것은 교수자와 튜터의 개념을 멘토와 코치의 개념으로 대체할 것이다. 게다가 신 시대에서의평생 학습은 지리학적, 규율적, 그리고 유형적 경계간의 흔들림을 보여 줄 것이다. 국제어로서의 영어에 대한 통용 등으로 초국가적 교육이 더욱 지배적일 것이다. 또한 지식 분야간 경계들은 허물어질 것이다. 특정 노동시장의 요구를 반영한 특별한 프로그램의 형태를 지닌 초지식적융합교육이 부상하게 될 것이다. 직업교육의 기초, 고등, 기술 교육과 같이 형식적 교육, 비형식적 교육 그리고 무형식 교육 간의 엄격한 경계들은 이러한 교육의 형태들 사이의 밀접한 소통에 따라 이제는 허물어질 것이다. 더욱이 프로그램들은 다양한 시작점과 종료점을 보일 것이다.자유입학제도, 자유 교육기간, 그리고 학습자원에 대한 공개 등과 같은 교육관리적 접근에서 뚜렷하게 나타날 개방교육은 또 하나의 새로운 경향이다. 게다가 유비쿼터스 환경은 평생 학습에서 주요 경향이 될 것이다. 학습은 넷북과 이동전화와 같은 단말기와 클라우드 컴퓨팅, 그리고WiFi와 WiMAX 서비스 등을 통해서 언제 어디서든 일어날 수 있는 것이다.마지막으로, 본 연구지를 통해 평생 학습 수요자들의 변화에 관한 이야기를 나누고자 한다. 이전에는 평생 학습의 기회들이 교육에의 접근이 근본 이슈였던 외곽 지역의 극빈자들을 위한 것이었다. 평생학습은 교육의 기회가 동등히 부여되지 않았던 소외층, 과년(過年)층, 그리고 여성들을 대상으로 하여왔다. 이제는 새로운 전달 체제의 결과로써 부유층, 전문가, 그리고 고등 교육자들이 소외층보다 더 많이 평생 학습의 기회를 활용하고 있다.
        4,300원
        1788.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We present the performance test results of VLBI Correlation Subsystem (VCS) trial product which was being developed for 1 year from August 2007. It is a core component of Korea-Japan Joint VLBI Correlator (KJJVC). The aim for developing VCS trial product is to improve the performance of VCS main product to reduce the efforts and cost, and to solve the design problems by performing the preliminary test of the manufactured trial product. The function of VCS trial product is that it is able to process the 2 stations-1 baseline, 8 Gbps/station speed, 1.2 Gbps output speed with FX-type. VCS trial product consists of Read Data Control Board (RDC), Fourier Transform Board (FTB), and Correlation and Accumulation Board (CAB). Almost main functions are integrated in the FTB and CAB board. In order to confirm the performance of VCS trial product functions, the spectral analysis, delay compensation and correlation processing experiments were carried out by using simulation and real observation data. We found that the overflow problem of re-quantization after FFT processing was occurred in the delay compensation experiment. We confirmed that this problem was caused by valid bit-expression of the re-quantized data. To solve this problem, the novel method will be applied to VCS main product. The effectiveness of VCS trial product has been verified through the preliminary experimental results, but the overflow problem was occurred.
        5,100원
        1789.
        2009.12 KCI 등재 구독 인증기관·개인회원 무료
        The word spawn is derived from an old French verb, espandre , meaning to spread out or expand. Spawn is also defined as “the mycelium of fungi, especially of mushrooms grown to be eaten, used for propagation.” The effects of bag spawn to sawdust substrate on the growth of Pleurotus ostreatus were conducted. The duration of mycelial growth and days of pinhead formation of bag spawn(2.5kg) were 18~19 days and 7~8 days, whereas bottle spawn (1,000㎖) was 18 days and 6 days, respectively. The yield of mushroom fruitbody was that bag spawn is 100~118g, bottle spawn was 95~115g. In economical analysis, bag spawn is increased to 50%, compared to bottle spawn in relative income.
        1790.
        2009.12 KCI 등재 구독 인증기관·개인회원 무료
        Ganoderma applantaum belonged to Polyporaceae of Basidiomycetes and has been known as one of the popular medicinal mushrooms due to high antitumor and anti-diabetes activity. This study was carried out to obtain the basic information for mycelial culture conditions of Ganoderma applantaum. According to colony diameter and mycelial density, the media for suitable mycelial growth of them were shown in PDA and MEA. The optimum temperature for mycelial growth was 25~30℃The colonies are white, flocculose and underside of the plates is whitish to cream. Carbon and nitrogen sources were mannose and malt extract, respectively. The optimum C/N ratio was 10:1 to 5:1with 2% glucose concentration, vitamin was thiamine- HCl, organic acid was succinic acid, and mineral salt was MgSO4ㆍ7H2O. Present experiments were conducted to determine the possibility of artificial culture with sawdusts of G. applantaum. The pH value which was 6.0 of oak sawdust and6.4 of ricebran. Mycelial density on oak sawdust of G.applantaum spp. was higher than Ganoderma lucidium (a control). Wt. of dried fruiting body (g) of G. applantaum. (origin culture: GBEA-01, strain name: SamJung(三淨)) showed that 16.0 g on oak sawdust bottle cultivation (850㎖), 7.8 g on oak sawdust and G. lucidum. This present study was undertaken to investigate comparative anti-tumor activity of water extracts of G. lucidum ASI 7125 (GLE), G. applantaum SamJung (GAE) in vitro. The anti-tumor activity in the present study was evaluated by sulforhodamine B (SRB) and microtetrazolium (MTT) assay in terms of cell survival level. The results showed that DW, GLE and GAE inhibited proliferation showing both tumor cells.
        1791.
        2009.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        More than a century before Grotius wrote his famous work on international law, his countryman Desiderius Erasmus of Rotterdam laid the foundations for the modern critique of war. In several writings, especially those published in the period 1515- 1517, the “prince of humanists”brilliantly and devastatingly condemned war not only on Christian but also on secular/rational grounds. His graphic depiction of the miseries of war, together with his impassionate plea for its avoidance, remains unparalleled. Erasmus argued as a moralist and educator rather than as a political theorist or statesman. If any single individual in the modern world can be credited with“ the invention of peace,”the honour belongs to Erasmus rather than Kant whose essay on perpetual peace was published nearly three centuries later.
        6,000원
        1794.
        2009.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Unreported dielectrics based on the binary system of MgO-SiO2 were investigated as potential candidates for microwave dielectric applications, particularly those demanding a high fired density and high quality factors. Extensive dielectric compositions having different molar ratios of MgO to SiO2, such as 2:1, 3:1, 4:1, and 5:1, were prepared by conventional solid state reactions between MgO and SiO2. 1 mol% of V2O5 was added to aid sintering for improved densification. The dielectric compositions were found to consist of two distinguishable phases of Mg2SiO4 and MgO beyond the 2:1 compositional ratio, which determined the final physical and dielectric properties of the corresponding composite samples. The increase of the ratio of MgO to SiO2 tended to improve fired density and quality factor (Q) without increasing grain size. As a promising composition, the 5MgO.SiO2 sample sintered at 1400 ˚C exhibited a low dielectric constant of 7.9 and a high Q × f (frequency) value of ~99,600 at 13.7 GHz.
        4,000원