• Journal of the Korean Magnetics Society
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• v.22 no.3
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• pp.79-84
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• 2012

Nano-magnetic materials such as iron-nitrides have been actively studied as an alternative to the application of high density, high performance needs for next generation information storage and also alternative to the rare earth and neodymium magnet. $Fe_4N$ is the basic materials for magnetic storage media and is one of the important magnetic materials in focus because of its higher magnetic recording density and chemical stability. Single phase ${\gamma}^{\prime}-Fe_4N$ nanoparticles have been prepared by a PAD (Plasma Arc Discharge) method and nitriding in a $NH_3-H_2$ mixed gases at temperature, $400^{\circ}C$ for 4 hrs. Also $Fe_{17}Sm_2N_x$ powders were synthesized by nitriding after reduction/diffusion of $Fe_{17}Sm_2$ to compare the magnetic properties with nano-sized $Fe_4N$ particles. The saturation magnetization of $Fe_4N$ and $Fe_{17}Sm_2N_x$ were 149 and 117 emu/g, respectively, but the coercive force was considerably smaller than that of bulk or acicular $Fe_4N$.

• Korean Journal of Microbiology
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• v.12 no.2
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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.

• The KIPS Transactions:PartA
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• v.16A no.4
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• pp.299-306
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• 2009

Hierarchical Folded HyperStar Network has lower network cost than HCN(n,n) and HFN(n,n) which are hierarchical networks with the same number of nodes. In this paper, we analyze embedding between Hierarchical Folded HyperStar HFH($C_n,C_n$) and Hypercube, HCN(n,n), HFN(n,n). The results of embedding are that HCN(n,n), HFN(n,n) and Hypercube $Q_{2n}$ can be embedded into HFH($C_n,C_n$) with expansion $\frac{C^n}{2^{2n}}$ and dilation 2, 3, and 4, respectively. Also, HFH($C_n,C_n$) can be embedded into HFN(2n,2n) with dilation 1. These results mean so many developed algorithms in Hypercube, HCN(n,n), HFN(n,n) can be used efficiently in HFH($C_n,C_n$).

• Journal of the Korean Chemical Society
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• v.27 no.2
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• pp.83-94
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• 1983

The effects of cis and trans configurations of ligands for $[M(II)O_3N_3]$ and $[Ni(II) O_2N_4]$ type complexes [M(II) = Co(III), Ni(II) and Cu(II)] on the calculated dipole moments have been investigated, adpoting the eigenvectors of EHT calculation. The calculated dipole moments for cis complexes are higher than those of trans complexes. The calculated dipole moments for the octahedral trans $[Co(III)O_3N_3]$ type complex fall in the range of experimental values. However the calculated dipole moments for cis $[Ni(II) O_2N_4]$ type complexes fall in the range of the experimental values. These results predicts the trans structure for $[Co(III)O_3N_3]$ and $[Ni(II) O_2N_4]$ type complexes. Those structures are in agreement with the experimental one (Three bidentate (O-N) ligands in $[M(II)O_3N_3]$ type complexes coordinate to the metal ion and two tridentate (O-N-N) ligands in [Ni(II)O2N4] type complexes coordinate to Ni(II) ion).

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.11
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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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• v.32 no.5
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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.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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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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• v.9 no.2
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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.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2005.05a
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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.

• Korean Journal of Crystallography
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• v.8 no.2
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• pp.132-137
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• 1997

The crystal structure of N,N'-di-tert-butoxycabonyl-2,7-diazabicyclo[3.3.0]oct-4-ene has been determined from single crystal x-ray diffraction study; C16H26N2O4, Triclinic, P1, a=11.119(1) Å, b=13.638(1) Å, c=6.214(1) Å, α=92.14(1)°, β=103.49(1)°, γ=73.35(1)°, V=877.4(2)Å3, T=293(2)K, Z=2, CuKα(λ=1.5418Å). The structure was solved by direct method and refined by full-matrix least squares to a final R=5.38% for 2389 unique observed F0>4σ(F0) reflections and 225 parameters.