• 한국자기학회지
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• 제22권3호
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• pp.79-84
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• 2012

나노크기의 물질이 가지는 새로운 특성을 응용하는 연구가 매우 활발하게 진행되어 지고 있다. 본 연구에서는 PAD법으로 제조한 ${\alpha}$-Fe 나노분말을 이용하여 높은 포화자화와 기계적인 경도, 화학적 안정성, 작은 입자로 인한 tape noise의 감소 등의 특성을 지니고 있는 질화철인 $Fe_4N$을 합성하고, 이를 환원/확산법과 $N_2$가스 질화법으로 합성한 $Fe_{17}Sm_2N_x$ 자성분말과 자성 특성을 비교하였다. $NH_3+H_2$(부피비 3 : 1) 혼합가스를 이용하였을 경우 $Fe_4N$의 생성 온도와 반응시간 등의 조건 변수를 통해 $400^{\circ}C$에서 4시간 동안 열처리함으로서 단일상의 $Fe_4N$이 생성되는 것을 관찰 할 수 있었으며, 나노크기의 $Fe_4N$ 분말과 마이크론 크기의 $Fe_{17}Sm_2N_x$ 분말의 포화자화의 값은 각각 149, 117 emu/g의 값을 나타내었다.

• 미생물학회지
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• 제12권2호
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• pp.77-84
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• 1974

In order to study 5-nitro-2-furaldehyde derivatives having more effective antibacterial activity, four new $N^4$-(5-nitro-2-furfurylidene)-$N^1$-substituted sulfanilamides$N^1$-3,4-dimethyl-5-isoxazoyl-$N^4$-5-nitro-2-furfurylidene sulfanilamide, $N^1$-4,6-dimethyl-2-pyrimidyl-$N^4$-5-isoxazoyl-$N^4$-5-nitro-2-furfurylidene sulfanilamide, $N^1$-6-methoxy-3-pyridazinyl-$N^4$-5-nitro-2-furaldehyde with sulfa drugs such as sulfisoxazole, sulfamethazine, sulfamethoxypyridazine, and sulfadimethoxine. All compounds were tested for antibacterial activity in vitro on the following micro-organisms : Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Proteus vulgaris. Each compound exhibited a fair bacteriostatic activity against each microorganism. Above all, sulfisoxazole derivatives showed higher activity than the others. Each compound was most active against Staphylococcus aureus, whereas least active against proteus vulgaris.

• 정보처리학회논문지A
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• 제16A권4호
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• pp.299-306
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• 2009

계층적 폴디드 하이퍼스타 네트워크는 동일한 노드 개수를 갖는 계층적 네트워크인 HCN(n,n)과 HFN(n,n)보다 망비용이 우수한 연결망이다. 본 연구에서는 하이퍼큐브, HCN(n,n), HFN(n,n)과 계층적 폴디드 하이퍼스타 HFH($C_n,C_n$) 사이의 임베딩을 분석한다. 임베딩 결과는 HCN(n,n), HFN(n,n), 하이퍼큐브 $Q_{2n}$은 계층적 폴디드 하이퍼스타 HFH($C_n,C_n$)에 확장율 $\frac{C^n}{2^{2n}}$과 연장율 2, 3, 4로 각각 임베딩 가능하다. 또한, 계층적 폴디드 하이퍼스타 HFH($C_n,C_n$)는 계층적 네트워크인 HFN(2n,2n)에 연장율 1에 임베딩 가능하다. 이러한 임베딩 결과는 하이퍼큐브, HCN(n,n), HFN(n,n)에서 개발된 알고리즘을 계층적 폴디드 하이퍼스타 HFH($C_n,C_n$)에서 효율적으로 활용 가능함을 의미한다.

• 대한화학회지
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• 제27권2호
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• pp.83-94
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• 1983

EHT calculation의 고유함수를 사용하여 $[M(II)O_3N_3]$ 및 $[Ni(II) O_2N_4]$ 형태착물[M(II) = Co(III), Ni(II) 및 Cu(II)]의 쌍극자 모멘트에 대한 cis 및 trans 구조의 영향을 고찰하였다. cis$[M(Ⅱ)O_3N_3]$ 형태착물의 계산한 쌍극자 모멘트가 trans착물의 계산한 쌍극자 모멘트 값보다 큰 값을 가지며 trans 착물의 쌍극자 모멘트 값이 실험치 범위안에 들었다. 그러나 $[Ni(II) O_2N_4]$ 착물의 경우 cis 착물의 쌍극자 모멘트 값이 실험치 범위안에 들었다. 이 결과는 $[Co(III)O_3N_3]$ 형태착물이 trans 구조, $[Ni(II) O_2N_4]$ 형태착물은 cis 구조를 가졌음을 암시하며 이는 실험결과와 일치한다. $[M(II)O_3N_3]$ 형태착물에서 세개의 두자리 (O-N)리간드가 금속이온에 배위되어 있으며 $[Ni(II) O_2N_4]$형태 착물에서는 두개의 세자리(O-N-N) 리간드가 Ni(II) 이온에 배위되어 있음).

• Asian-Australasian Journal of Animal Sciences
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• 제13권11호
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• pp.1518-1522
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• 2000

Since the n-6 polyunsaturated fatty acid, docosatetraenoic acid (22:4n-6), is a major functional constituent of avian spermatozoa, the effects of two dietary oils rich in fatty acids which are metabolic precursors of 22:4n-6 on the fatty acid profiles of testicular lipids were investigated during a 39 week period of supplementation from 21 to 60 weeks of age. The effects on liver lipids were determined for comparison. Dietary supplementation of male chickens with Arasco Oil, which provides a large amount of arachidonic acid (20:4n-6), increased the proportion of 20:4n-6 in liver phospholipid by almost 2.5-fold. Although liver phospholipid normally contains very little 22:4n-6, this proportion was significantly increased as a result of Arasco feeding, indicating that the conversion of 20:4n-6 to 22:4n-6 was occurring. The phospholipid of the testis contains much higher proportions of 20:4n-6 and particularly of 22:4n-6 than the liver; supplementation with Arasco Oil significantly increased the proportions of both these polyunsaturates in testis phospholipid but the magnitude of this effect was much lower than that which occurred in the liver. Dietary supplementation with Evening Primrose Oil which contains ${\gamma}-linolenic $ acid (18:3n-6) resulted in significant increases in the proportions of 20:4n-6 and 22:4n-6 in liver phospholipid, although the extent of this increase was less than that produced by the Arasco Oil. By contrast, the feeding of Evening Primrose Oil did not alter the fatty acid composition of phospholipid in the testis. The findings raise the possibility that dietary supplementation with Arasco Oil may modulate the fatty acid profile of avian spermatozoa in a way which could potentially be beneficial for fertility. Moreover, the weights of the testes were almost doubled as a result of supplementation with Arasco Oil or Evening Primrose Oil.

• Bulletin of the Korean Chemical Society
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• 제32권5호
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• pp.1475-1482
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• 2011

New spiro[benzo[c]fluorene-7,9'-fluorene] (SBFF)-based blue host materials, 9-phenyl-SBFF (BH-4P) and 5,9-diphenyl-SBFF (BH-6DP), were successfully prepared by spiro-formation of 9-phenyl-7H-benzo[c]fluoren-7-one with 2-bromobiphenyl via lithiation and reaction of 5,9-dibromo-SBFF with phenylboronic acid through the Suzuki reaction, respectively. Diphenyl-[4-(2-[1,1;4,1]terphenyl-4-yl-vinyl)-phenyl]-amine (BD-1) and N,N-diphenyl-N',N'-diphenyl-SBFF-5,9-diamine (BD-6DPA) were used as dopant materials. Blue OLEDs with the configuration ITO/N,N'-bis-[4-(di-m-tolylamino)phenyl]-N,N'-diphenylbiphenyl-4,4'-diamine (DNTPD)/bis[N-(1-naphthyl)-N-phenyl]benzidine (NPB)/host:5% dopant/SFC-137/Al-LiF were prepared from the two host materials doped with BD-1 and BD-6DPA dopants and the devices composed of BH-4P and BH-6DP doped with BD-6DPA showed blue EL spectra at 458 and 463 nm at 7 V and luminance efficiencies of 4.58 and 4.88 cd/A, respectively.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.655-659
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• 2002

This study is performed to develop the Si$_3$N$_4$ based ceramic inserts. Si$_3$N$_4$with addition of SiC and A1$_2$O$_3$ is investigated to determine the possibility to be a new tool. The tool life of Si$_3$N$_4$ insert with more than 20wt% SiC is shorter than commercial Si$_3$N$_4$ insert during machining both heat treated SCM440 and gray cast iron. Even though SiC has higher hardness than Si$_3$N$_4$, its chemical affinity to the iron on high temperature may causes deteriorat ion of tool life. To the contrary, Si$_3$N$_4$insert with A1$_2$O$_3$ shows increase of tool life up to 300% compared to the commercial Si$_3$N$_4$insert. It may attribute to the high temperature stability of A1$_2$O$_3$. Further study will be focused on the optimization of ceramic inserts with the composition of Si$_3$N$_4$and A1$_2$O$_3$.

• Tribology and Lubricants
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• 제9권2호
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• pp.63-69
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• 1993

The wear properties of two types of $Si_3N_4$(silicon nitride) exposed to high and low humidity were examined experimentally for various sliding speed. Bearing steel was used as the disk material at pin-on-disk type sliding. Wear rates of pressureless sintered-plus-hot-isostatic pressed Si3N4 were slightly lower than those of pressureless sintered $Si_3N_4$. It was observed that adsorbed moisture and sliding speed markedly influenced the wear properties of $Si_3N_4$. The highest wear rate was obtained under the high humidity and low sliding speed condition. As the sliding speed was increased, wear rates were decreased and the humidity effect on the wear rates of $Si_3N_4$ was lowered. The result that the $Si_3N_4$ pin showed a high wear rate under the high humidity condition was explained by the property change due to the adsorbed moisture, plowing action by the hard particles of $Fe_2O_3$ from the disk, and the corrosion effect at $Si_3N_4$ surface. Increase in sliding speed was supposed to have reduced the humidity effect on wear rate of $Si_3N_4$ by raising the temperature of both the bearing steel disk and $Si_3N_4$ pin specimen.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2005년도 봄 학술발표회지 제14권(제1호)
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• pp.377-379
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• 2005

실험실 규모의 토양컬럼을 사용하여 고농도의 암모니아성 질소의 질산화 영향을 실험한 결과 다음과 같은 결론을 얻었다. 1) 유입수 NH$_{4}$-N의 농도 50 mg/L와 100 mg/L인 경 우 HRT 48시간에서도 NH$_{4}$-N가 99%정도 제거되었으며 유출수 평균 NO$_{3}$-N의 농도는 각각 46.3 mg/L와 98.3 mgh로 유입수 NH$_{4}$-N는 대부분 NO$_{3}$-N로 전환되었다. 2) 유입수 NH$_{4}$-N의 농도 200 mg/L인 경우 HRT 48시간에서 NH$_{4}$-N의 평균제거율이74.8%에 머물렀으나 토양컬럼 내부에 폭기장치를 설치한 결과 NH$_{4}$-N의 평균제거율은 94.7%로 개선되는 효과를 나타냈으며, 유입수 NH$_{4}$-N의 농도 400 mg/L인 경우에는 HRT 72시 간에서도 질산화가 불안정하였으나 마찬가지로 강제 폭기를 실시 한 결과 질산화가 증가하는 경향을 보였다. 4) 실험종료 후 토양컬럼 내부의 암모니아 및 아질산 산화세균을 조사한 결과 각각 1.4${\times}$10$^{5}$과 2.3${\times}$ 10$^{6}$ MPN/g${\cdot}$soil까지 증가하였다.

• 한국결정학회지
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• 제8권2호
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• pp.132-137
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• 1997

N,N'-di-tert-butoxycabonyl-2, 7-diazabicyclo[3.3.0]oct-4-ene의 분자 및 결정구조를 X-선 회절법으로 연구하였다. 이 결정의 분자식은 C16H26N2O4, 결정계는 삼사정계이고 공간군은 P1이다. 단위세포상수 a=11.119(1) Å, b=13.638(1) Å, c=6.214(1) Å이며, α=92.14(1)°, β=103.49(1)°, γ=73.35(1)°, V=877.4(2)Å3, T=293(2)K, Z=2이다. 구조해석에 사용한 X-선은 Cu Kα선(λ=1.5418Å)이다. 구조는 직접법으로 풀었으며, 최소자승법으로 정밀화하였다. 최종 신뢰도 R값은 F0>4σ(F0)인 2389개의 독립회절데이타에 대해 5.38%이였다.