RISS 학술연구정보서비스

검색
다국어 입력

http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.

변환된 중국어를 복사하여 사용하시면 됩니다.

예시)
  • 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
  • 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
닫기
    인기검색어 순위 펼치기

    RISS 인기검색어

      검색결과 좁혀 보기

      • 좁혀본 항목

      • 좁혀본 항목 보기순서

        • 원문유무
        • 음성지원유무
        • 원문제공처
        • 등재정보
        • 학술지명
        • 주제분류
        • 발행연도
        • 작성언어
        • 저자

      오늘 본 자료

      • 오늘 본 자료가 없습니다.
      더보기
      • 무료
      • 기관 내 무료
      • 유료
      • KCI등재후보

        Nd - Fe - B계 소결자석의 자기적특성 향상 연구

        김윤배(Yoon B. Kim), 정우상(W.S. Jung), 정원용(W.Y. Jeung) 한국자기학회 2002 韓國磁氣學會誌 Vol.12 No.2

        Nd-Fe-B계 소결자석의 특성을 향상시키기 위해서는 Nd-Fe-B계 합금의 조성 및 제조공정을 조절하여 자성분말의 입도 및 입도분포, 강자성상인 Nd₂Fe₁₄B상의 분율, 자성분말의 배향도, 산소 함량, grain size 등과 같은 factor들을 최적화 하여야 한다. 본 연구에서는 실험실 규모로 Nd-Fe-B계 합금 조성 및 공정 조절을 통하여 Nd-Fe-B계 소결자석을 제조하는 연구를 수행하였으며, 분쇄매체, 분쇄시간 및 ball size에 따른 Nd-Fe-B계 소결자석의 자기적특성을 분석하여 최적의 분쇄조건을 조사하였다. 또한 분쇄공정 중 FeGa합금을 첨가하여 잔류자속밀도의 감소없이 Nd-Fe-B계 소결자석의 보자력을 향상시킬 수 있었다. 이와 같은 분쇄 조건의 연구, FeGa 합금에 의한 보자력 향상, 건식분쇄 방법 및 powder blending 공정을 적용하여 잔류자속밀도(Br) : 14.4 kG, 보자력(iHc) : 9.4 kOe, 최대자기에너지적((BH)max.) : 47 MGOe의 자기적 특성을 갖는 Nd-Fe-B계 소결자석을 제조하였다. In order to increase the magnetic properties of a Nd-Fe-B sintered magnet, the general factors including particle size and its distribution, volume fraction of Nd₂Fe₁₄B phase, degree of alignment of Nd₂Fe₁₄B grain, oxygen content and grain size etc. should be optimized by controlling the composition of Nd-Fe-B alloy as well as the manufacturing process. In this study, fabrication of the Nd-Fe-B sintered magnet was carried out in a laboratory scale by controlling the composition of Nd-Fe-B alloy and the manufacturing process. The optimum milling condition was found by investigating the milling media, milling time and ball size. The addition of FeGa was effective to increase the coercivity of the Nd-Fe-B sintered magnet. A remanence of 14.4 kG, a coercivity of 9.4 kOe and a maximum energy product of 47 MGOe were obtained from the sintered magnet.

      • KCI등재

        Nd₂Fe₁₄B 희토류 영구자석의 전자기적 물성연구

        민병일(B. I. Min), 정윤희(Y. H. Jeong), 양충진(C. J. Yang) 한국자기학회 1992 韓國磁氣學會誌 Vol.2 No.3

        희토류 영구자석, Nd₂Fe₁₄B 화합물에 대한 자체충족적 국재밀도함수근사 전자 구조 계산을 수행하여 이 물질의 전자기적 물성을 연구하였다. LMTO(Linearized Muffin-Tin Orbital)에너지 띠 방법을 사용하여 상자성, 강자성상에서 구한 Nd₂Fe₁₄B 화합물의 에너지 띠구조를 토대로 하여 자성을 포함한 제반 물성, 즉 희토류금속과 천이금속의 결합(bonding)효과, 전기적, 자기적 구조등을 고찰하였다. Boron원자의 역학은 근접 Fe 원자와의 혼합 상호작용을 통하여 Fe의 원자의 자기모멘트를 많이 줄이는 효과를 주며 또한 구조 안정성에 기여한다는 결과를 얻었다. 강자성상에서의 Fe 원자들의 평균 자기모멘트는 약 2.15 μ_B로 계산되었는데 이중 Boron 원자로부터 가장 멀리 떨어져 있으며 12개의 Fe 원자들로 둘러싸인 Fe (j2-site)원자가 가장 큰 값(2.7 μ_B)의 자기모멘트를 갖고 Boron 원자와의 혼합 상호작용이 가장 큰 Fe(e-site)원자가 가장 작은 값(1.9 μ_B)의 자기모멘트를 갖는다. Electronic and magnetic propertis of the rare-earth permanent magnet, Nd₂Fe₁₄B, are investigated by performing self-consistent local density functional electronic structure calculations. Employing the LMTO (linearized muffin-tin orbital) band method, we have obtained the electronic band structures for both paramagnetic and ferromagnetic phases of Nd₂Fe₁₄B. Based on the energy band structures, we have studied various physical properties, such as electronic and magnetice structures, we have studied various physical properties, such as electronic and magnetic structures and the bonding effect between the rare-earth and transition metals. It is found that the boron atom substantially reduces the magnetic moment of neighboring Fe atoms through the hybridization interaction and that it plays an important role in stabilizing the structure. The average magnetic moment of Fe atoms in the ferromagnetic phase is estimated to be 2.15 μ_B. The Fe atom in the j2-site, which is located farthest from the B atom and surrounded by 12 Fe nearest neighbors, has the biggest magnetic moment (2.7 μ_B), while the Fe in the e-site, which interacts most strongly with B atoms, has the smallest magnetic moment (1.9 μ_B).

      • KCI등재SCOPUS

        Morphological, ecological and biological variations in the mustard aphid, Lipaphis pseudobrassicae (Kaltenbach) (Hemiptera: Aphididae) from different host plants

        B.K.,Agarwala,Kalpana,Das,Parichita,Raychoudhury 한국응용곤충학회 2009 Journal of Asia-Pacific Entomology Vol.12 No.3

        Genetic and morphological differentiation of insect populations in relation to the use of different host plants is an important phenomenon that leads to ecological specialization. In this study, we describe variations in morphology, and in ecological and biological parameters of Lipaphis pseudobrassicae (Kaltenbach) clones associated with three host species of Cruciferae, Brassica juncea (L.) var. rai sarson Czern and Cross (brown mustard), Brassica campestris L. var. sarson Prain (yellow mustard), and Rorippa indica (L.) Hiern (wild herb). This study was aimed at obtaining evidence regarding phenotypic differentiation induced by, or associated with, the use of distinct host species. Ten morphological characters, 4 growth parameters and 8 biological functions were investigated in wingless aphids collected from plants of the three host species. Aphids from B. campestris and B. juncea clones were bigger in size, heavier in weight and showed higher growth rates and fecundity than the clones from R. indica. Between the two crop plants, clones from B. juncea showed significantly higher growth rates than the clones from B. campestris. Transfer of L. pseudobrassicae populations from B. campestris to B. juncea and R. indica and vice versa resulted in poor performance. Results indicate that the average phenotype of L. pseudobrassicae individuals inhabiting different host plant species differs as a consequence of the contrasting feeding environments the host species provide. Genetic and morphological differentiation of insect populations in relation to the use of different host plants is an important phenomenon that leads to ecological specialization. In this study, we describe variations in morphology, and in ecological and biological parameters of Lipaphis pseudobrassicae (Kaltenbach) clones associated with three host species of Cruciferae, Brassica juncea (L.) var. rai sarson Czern and Cross (brown mustard), Brassica campestris L. var. sarson Prain (yellow mustard), and Rorippa indica (L.) Hiern (wild herb). This study was aimed at obtaining evidence regarding phenotypic differentiation induced by, or associated with, the use of distinct host species. Ten morphological characters, 4 growth parameters and 8 biological functions were investigated in wingless aphids collected from plants of the three host species. Aphids from B. campestris and B. juncea clones were bigger in size, heavier in weight and showed higher growth rates and fecundity than the clones from R. indica. Between the two crop plants, clones from B. juncea showed significantly higher growth rates than the clones from B. campestris. Transfer of L. pseudobrassicae populations from B. campestris to B. juncea and R. indica and vice versa resulted in poor performance. Results indicate that the average phenotype of L. pseudobrassicae individuals inhabiting different host plant species differs as a consequence of the contrasting feeding environments the host species provide.

      • KCI우수등재

        반축가축영양;호맥건초의 생육단계와 절단이 산양의 질소 및 Energy Balance 에 미치는 영향

        전병태,문상호,광전수헌 한국축산학회 1995 한국축산학회지 Vol.37 No.1

        This experiment was carried out to study associative effects of the chopping of hay at two stages of maturity on the nitrogen balance, nutritive value and energy balance in goats fed rye hay. Twelve Japanese goats were fed rye hay ad libitum in a unchopped form or chopped to 2 cm of chopping lengths. They were grouped into tetrads as follows: B I and B II were fed with unchopped and chopped hay at the boot stage, H I and H II were led unchopped and chopped hay at the heading stage respectively. Nitrogen intake(NI) and digestible nitrogen (DN) were significantly higher(p$lt;0.05) in groups (B I and B II) fed hay at boot stage ttran in groups(H I and H II) fed hay at heading stage. However, the differences corresponding with the chopping of hay were not accepted at both growth stages. Nitrogen losses as feces(FN) and urine(UN) were similar to the results for NI and DN, RN was high in groups(B I and B II) fed hay at the boot stage, although there was no significant difference (p$gt;0.05), but that had little differences in relation to the chopping of hay at both growth stages. On the other hand, the ratio of FN to NI wars higher in H I and H II than in B I and B II, while there were no great differences(p$gt;0.05) between unchopped hay and chopped hay at both growth stages. The ratio of UN to NI was similar of both growth stages. GE in groups(H I and H II) fed hay at the heading stage were significantly higher(p$gt;0.05) than those in groups fed hay at the boot stage. However, DE and ME were greater in groups(B I and B II) fed hay at the boot stage, although there was no significant difference for ME. TDN and DCP were also significantly higher(p$gt;0.05) in B I and B II than in H I and H II. No differences were recognized corresponding to the chopping of hay at both stages for GE, DE, ME, TDN and DCP. EI was a little lower in H I and H II than in B I and B II but was not significant. Energy lasses in FE, UE, CH, and HP did not differ in relation to the chopping and growth stage of hay. RE was 148.9, 108.9, 23.2 and 51.9 MJ/㎏W^(0.75) for B I, B II, H I and H II respectively, and thus RE in groups(B I and B II) fed hay at boot stage were significantly larger(p$lt;0.05) than those in groups(H I and H II) fed hay at heading stage. But there were no effects of the chopping of hay at both growth stages. RE was closely related with dry matter and energy intake(p$lt;0.05), especially with digestible dry matter and digestible energy intake(p$lt;0.01).

      • On the range kernel orthogonality of derivations

        Duggal,,B.P. TOPOLOGY AND GEOMETRY RESEARCH CENTER 1998 Proceedings of the Topology and Geometry Research Vol.9 No.-

        Let H be a separable infinite dimensional complex Hilbert space, and let B(H) denote the algebra of operators on H into itself. The generalized derivation δA,B : B(H) → B(H) is defined by δA,B (X) = AX - XB; let △A,B : B(H) → B(H) be defined by △A,B (X) = AXB - X, and let d A,B denote δA,B or △A,B . Given that S ∈ Cp (the Schatten p-class, 1 < p < ∞) and that the pair of operators A and B* satisfies a Putnam-Fuglede commutativity theorem type property, we consider here a necessary and sufficient condition for ∥dA,B (X) + S∥p ≥ ∥S∥ p to hold for all X ∈ C p.

      • 反芻胃 Celluloytic Bacteria에 의한 섬유소 분해 및 비구조 탄수화물의 이용성에 관한 硏究

        민병렬,김범석,맹원재 건국대학교 동물자원연구센터 1991 動物資源硏究誌 Vol.16 No.-

        본 실험은 반추위내에 존재하는 주요한 cellulolytic bacteria를 選擇 및 非選擇培地를 사용하여 면양의 rumen내에 존재하는 celluloytic bacteria를 사용하여 纖維素 分解菌 각각의 纖維素源의 分解度, 비구조 탄수화물의 이용성 및 휘발성 지방산의 생성량을 측정하였다. 본 실험결과를 요약해 보면 다음과 같다. 1) In vitro상에서 Corn stover, alfalfa, rice straw 및 filterpaper No.1등의 섬유소원에 대한 R.flavefaciens의 평균 DM 소화율은 10.75%로 가장 높은 소화율을 나타내었으며, B.succinogenes, Buty. fibrisolvens 및 B. ruminicola subsp. 등은 각각 8.20%, 5.66% 및 2.5%의 DM소화율을 나타내었다.(p<0.05). 2) 섬유소원에서의 평균 microbial dry cell生成量은 R.flavefaciens. B.succinogenes, Buty.fibrisolvens 및 B.rumminicola subsp. 등이 각각 11.4, 4.47, 6.38 및 1.13mg/100ml를 가장 높은 미생물 cell의 생성량을 나타내었다. 3) ADF 및 NDF 평균 소화율은 R.flavefaciens가 가장 높았으며(23.61% 및 39.87%), B.succinogenses는 각각 11.16% 및 35.91%의 분해도를 나타내었다. Buty. fibrisolvens는 16.82% 및 24.34%로서 가장 낮은 분해도를 나타내었다. CEllulose消化率은 B.succinogenes가 14.43%로 R.flavefaciens(11.11%)보다 높은 분해율을 나타내었다. 4) 비구조 炭水化物 利用率은 (OD=670nm)R.flavefaciens가 mannose, arabinose 및 xylose 등을 가장 잘 이용하며, B. ruminicola subsp.은 galactose, mannose, arabinose 및 xylose등을 가장 잘 이용하는 것으로 나타났다. B.succinogenes는 glucose 및 rffainose를 가장 잘 이용하며, B.fibrisolvens는 glucose, galactose, arabinose, xylose 및 maltose등을 가장 잘 이용하는 것으로 나타났다. (P<0.05). 5) PYG basal medium에 炭水化物源을 각각 1g씩 첨가한 培養區에서 VFA 생성량은 R.flavefaciens는 주로 acetate, propionate, n-butyrate 및 succinate를 생산하는 것으로 나타났으며, 이것들의 생산량은 각각 81.65, 26.36, 20.16 및 108.91mM/100ml를 생산하여 succinate를 가장 많이 생산하는 것으로 나타났다. B.ruminicola subsp은 주로 acetate, propionate 및 n-butyrate를 생산하는 것으로 나타났으며, 이 균의 생산량은 각각 104.72, 31.32 및 26.12mM/100ml를 생산하였으며, B. succinogenes는 주로 acetate, propionate, n-butyrate 및 succinate를 생산하며, 이 균들의 생산량은 각각 87.66, 27.70 및 56.07mM/100ml 생산하였다. Buty.fibrisolvens는 주로 acetate, propionate 및 n-butyrate를 생산하는 것으로 나타났다. Fiber degradation of corn stover, rice straw, alfalfa or filter paper No.1 was evaluated using microscopy and in vitro analyses after incubation with pure culture of cellulolytic ruminal bacteria. 1) Analyses of the initial substrate and the recovered residue after 24h of static incubation showed that R.flavefaciens degraded a mean dry matter(10.75% versus 5.66%) more effectively than B. succinogenes. However, B, succinogenes demonstrated a qualitative advantage in degrading cellulose of particular substrates. DM digestibilities for alfalfa and rice straw. Treatment for 24h were 13.96% and 9.46% for R.lflavefaciens, 10.27% and 4.32% for B.succinogenes, and 7.74% and 2.31% for Buty. fibrisolvens(p<0.05). Bacteriodes ruminitola subsp. was unable to degrade plant cell wall components, while it degraded non-structural carbohydrates more actively than any other bacteria. Microbial cell DM yield(avg, 11.44mg/dl) was the highest for R. flavefaciens cultured with alfalfa substrate(p<0.05). 2) Ruminococcu flavefaciens degraded a mean 23.61% of the ADF and 39.87% of the NDF in the various substrates. whereas, B. succinogenes degraded a mean 11.6% and 35.91% of these fractions, respectively. 3) The utilization of carbodydrates was the highest for R.flavefaciens cultured with mannose and xylcse substrate, and for B. ruminicola subsp. with arabinose, xylose, raffinose and galactose respectively. B. succinogenes utilized glucose and raffinose, as major substrates fermentd(p<0.05) and Buty. fibrisolvens utilized glucose, galactose, arabinose, xylose and maltose. 4) Ruminococcus flavefaciens produced acetate, succinate and propionate, and B.ruminicola subsp. produced acetate, propionate and n-butyrate as major VFA. B.succinogenes produced acetate, propionate, n-butyrate and succinate, and Buty.fibrisolvens produced n-butyrate and acetate as major VFA.

      • SCIESCOPUSKCI등재

        EFFECTS OF DIETARY VITAMIN B<sub>6</sub> LEVELS ON LIPID CONCENTRATION AND FATTY ACID COMPOSITION IN GROWING CHICKS

        An,,B.K.,Tanaka,,K.,Ohtani,,S. Asian Australasian Association of Animal Productio 1995 Animal Bioscience Vol.8 No.6

        This experiment was designed to evaluate the effect of various dietary vitamin $B_6$ levels on conversion from linoleic acid to arachidonic acid in various tissues in growing chicks. Growing chicks were fed the purified diet containing 7% safflower oil with different levels of vitamin $B_6$ (0, 4, 8, 40, 80 mg per kg diet) for 14 days. Feed intake and weight gain in chicks fed the vitamin $B_6$-free diet were markedly depressed. Esterified and free cholesterol concentrations in serum were significantly higher, while the serum triglyceride concentration was significantly lover in chicks fed the vitamin $B_6$-free diet compared to that fed diets with vitamin $B_6$. The liver triglyceride content was also lower in chicks fed the vitamin $B_6$-free diet. The liver and serum cholesterol ester fractions in chicks fed the vitamin $B_6$-free diet showed higher rate of $C_{18:2n6}$ and lower rates of $C_{18:3n6}$, $C_{20:3n6}$ and $C_{20:4n6}$ as compared with vitamin $B_6$ fed groups. In serum phospholipid fraction of chicks fed the vitamin $B_6$-free diet, rates of $C_{20:3n6}$ and $C_{20:4n6}$ were markedly lower. As dietary vitamin $B_6$ level was increased, the rate of $C_{20:4n6}$ was slightly increased, although it was statistically not significant. The fatty acid compositions of adipose tissue showed almost the same pattern as those in liver and serum. This result suggests that the desaturation of $C_{18:2n6}$ to $C_{18:3n6}$, elongation to $C_{20:3n6}$ or both steps might be impaired by vitamin $B_6$ deficiency in growing chicks.

      • 刊內膽石症의 分類 및 手術法

        許景渤,兪熙,金益洙,閔珖植 順天鄕病院 1976 順天鄕醫報 Vol.1 No.1

        Intera-hepatic calculi, whech is a kind of gall stones found in the liver ducts, are frequently encountered during a surgical intervention of cholelithiasis at Korea. It has also been frequently observed in the South-Eastern area of Asia against its rarity in the States. Arather high incidence, perplexing clinical manifestations, controversial surgical treatment and a high reccurrence after an operative treatment are the common features. Dye-dilution operative cholangiogram may help to demonstrate a good delineation of the intra-hepatic calculi due to a sufficient amount of diluted dye (Hypaque) injection. Through this technic it is learned that the intra-hepatic calculi are frequently associated with ductal stenosis and the calculi are often retained in the intra-hepatic ducts proximal to the stenosis. Intrahepatic calculi are classified into 6 different types. As shown in the table, simple intrahepatic calculi are not associated with stenosis. Compound intrahepatic calculi are those that associated with stenosis of duct in some part of the liver, and according to the location of the stenosis drainage function of the corresponding liver segment may be disturbed and they are further subdivided. Type B-1. has stenosis in hepatic hilum. Type B-2. has stenonsis in left lobe of liver. Type B-3. has stenosis in right lobe of liver. difference between posterior and anterior segment of right lobe is clear and it is again divided into type. B-3-A and type B-3-P. Type B-4. has stenosis in both lobes of liver. According to the classified type of intrahepatic calculi surgical treatment may be individualized. Simple intrahepatic calculi are well treated by the conventional By-pass operation. But compound intrahepatec calculi are not responding well to the ordinary By-pass operation. In the compound intrahepatic calculi, drainage operation must be done at a point proximal to the stenosis. In the type B-1. hepatic hilum had to be exposed and Roux-en-Y hepatico-jejunost-omy was done. This 21-years-old man is doing well for over 8 years. In the type B-2. initial operation was Roux-en-Y choledocho-jejunostomy for multiple bilobar intrahepatic calculi, at the time of first operation. It was not aware of the presence of the left hepatic stenosis. 3 months later patient had recurrent pain and fell into a shock. Finally patient underwent partial left hepatec lobectomy and Roux-en-Y hepatico-jejunostomy. In the type B-3. Operative cholangiogram shows marked stenosis of right intrahepatic duct with stones. Cholecystectomy was done and Roux-en-Y type anastomosis between jejunum and side of common bile duct was done first. Dilated right intrahepatic duct was exposed and side to side hepatico-jejunostomy was added. Compound intrahepatic calculi of type B-3-p, where there would be no reasonal drainage operation, hepatec lobectomy may be indicated. Compound intrahepatic calculi of type B-4, are not primarily surgical subjicts but depedend on size of the calculi and patency of the stenosis, some small calculi may be expected to be drained into intestinal lumen and few patients were thus managed. In view of our clinical experiences, convevtional by-pass operation is worth only in the simple type of intrahepatic calculi, and in the compound intrahepatic calculi, operation must be all individualized. Compound type of B-3-P and B-4, however, are not entirely surgical problens.Rescent knowledge of cholesterol gall stone formation and possibility to dissolve it may potentiate management of residual calculi in near furture. Intrahepatec calculi are uaually pigmented stone and pathogenesis must be further investigated.

      맨 위로 스크롤 이동