• Journal of Ceramic Processing Research
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• 제17권7호
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• pp.763-767
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• 2016

The structural characterization of cubic boron nitride (c-BN) thin films was performed using a B4C target in a radio-frequency magnetron sputtering system. The deposition processing conditions, including the substrate bias voltage, substrate temperature, and base pressure were varied. Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy were used to analyze the crystal structures and chemical binding energy of the films. For the BN film deposited at room temperature, c-BN was formed in the substrate bias voltage range of -400 V to -600 V. Less c-BN fraction was observed as the deposition temperature increased, and more c-BN fraction was observed as the base pressure increased.

• Bulletin of the Korean Chemical Society
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• 제4권2호
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• pp.92-95
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• 1983

The addition products of glutathione to ${\beta}$ -nitrostyrene derivatives were synthesized. ${\beta}$ -Nitrostyrene (1a), p-methyl-${\beta}$-nitrostyrene (1b), 3,4,5-trimethoxy-${\beta}$-nitrostyrene (1c), o-, m- and p-chloro-${\beta}$-nitrostyrene (1e, 1f, 1g) and o-, m- and p-methoxy-${\beta}$-nitrostyrene (1h, 1i, 1j) undergo addition reactions with glutathione to form S-(2-nitro-1-phenylethyl)-L-glutathione (5a), S-[2-nitro-1-(p-methyl)phenylethyl]-L-glutatione (5b), S-[2-nitro-1-(3', 4', 5'-trimethoxy)phenylethyl]-L-glutathione (5c), S-[2-nitro-1-(o-chloro)phenylethyl]-L-glutathione (5e), S-[2-nitro-1-(m-choro)phenylethyl]-L-glutathione (5f), S-[2-nitro-1-(p-chloro)phenylethyl]-L-glutathione (5g), S-[2-nitro-x-(o-methoxy)-phenylethyl]-L-glutathion e(5h), S-[2-nitro-x-(m-methoxy)phenylethyl]-L-glutathion e (5i), and S-[2-nitro-1-(p-methoxy)phenylethy])-L-glutathione (5j), respectively. The structure of adducts were identified by UV and IR-spectra, molecular weight measurement, and elemental analysis.

• 한국재료학회지
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• 제18권12호
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• pp.678-682
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• 2008

This study investigates $Bi_2O_3$-$B_2O_3$-BaO-ZnO glass with variations of the $Co_3O_4$ content (0.25, 0.5, 1, and 2 wt%) and the interaction between transparent dielectric and Ag electrodes heat-treated at $500-560^{\circ}C$ for 30 min. The glass transition temperature, softening temperature and thermal expansion coefficient were $432^{\circ}C$, $460^{\circ}C$ and $81.4{\times}10^{-7}/^{\circ}C$, respectively. The transmittance of 0.25 wt% $Co_3O_4$ to which dielectric was added was highest and was decreased due to coloration with the addition of more than 0.25 wt%. However, without $Co_3O_4$, the transmittance of the transparent layer was decreased due to the formation of $Ba_5Bi_3$; however, the occurrence of the crystal phase decreased as a result of the addition of $Co_3O_4$. The amount of $Co^{2+}$ ions increased as the $Co_3O_4$ increased. With a maximum of $Co^{3+}$ ions, the highest transmittance was observed.

• 한국분말재료학회지
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• 제22권5호
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• pp.344-349
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• 2015

$MgB_2$ bulk superconductors are synthesized by the solid state reaction of ($MgB_4$+xMg) precursors with excessive Mg compositions (x=1.0, 1.4, 2.0 and 2.4). The $MgB_4$ precursors are synthesized using (Mg+B) powders. The secondary phases ($MgB_4$ and MgO) present in the synthesized $MgB_4$ are removed by $HNO_3$ leaching. It is found that the formation reaction of $MgB_2$ is accelerated when Mg excessive compositions are used. The magnetization curves of $Mg_1+_xB_2$ samples show that the transition from the normal state to the superconducting state of the Mg excessive samples with x=0.5 and x=0.7 are sharper than that of $MgB_2$. The highest $J_c-B$ curve at 5 K and 20 K is achieved for x=0.5. Further addition of Mg decreases the $J_c$ owing to the formation of more pores in the $MgB_2$ matrix and smaller volume fraction of $MgB_2$.

• 한국식품영양과학회지
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• 제25권6호
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• pp.899-906
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• 1996

본 연구에서는 솔잎즙을 김치에 첨가함으로써 솔잎이 김치의 발효 숙성에 미치는 영향을 조사하였다. 솔잎즙을 0, 0.5, 1.0 및 1.5% 첨가하여 제조한 김치를 실온에서 24시간 방치 후 $4^{\circ}C에서$ 15일 동안 숙성(A)또는 $15^{\circ}C에서$ 15일 동안 숙성(B)시키면서 숙성 0, 1, 2, 3, 4, 5, 7, 9, 11, 13 그리고 15일에 pH, 총 산, 환원당 및 총 비타민 C 함량 등 이화학적 특성 및 총 균수와 젖산균수 등 미생물학적 특성을 조사하였다. 솔잎즙 무첨가구의 pH는 숙성 3일에 적숙기의 pH와 유사한 pH 4.2에 도달한 반면, 솔잎즙 0.5, 1.0 및 1.5% 첨가구의 경우 각각 숙성 4, 5및 7일에 pH 4.2로 감소되어 솔잎즙을 첨가함에 따라 김치의 산패를 1~4일 정도 지연시켰다. 총 산 함량은 숙성이 진행됨에 따라 증가하였으며, 솔잎즙 무첨가구에 비해 솔잎즙 첨가구의 총 산 함량은 전반적으로 낮게 관찰되었다. 산도의 증가 및 pH의 감소는 A군에 비해 B군에서 보다 빨리 나타났다. 환원당 함량은 숙성 4~5일 동안 모든 처리구에서 약 80%정도 감소하였다. 총 비타민 C 함량은 모든 처리구에서 숙성 1일에 최고 수준에 도달한 뒤 감소하였다. 환원당 함량 및 총 비타민 C 함량은 솔잎즙 무처리구에서 보다 처리구에서 약간 높게 관찰되었으나, 이러한 결과는 솔잎 자체내에 함유된 환원당 및 비타민 C에 의한 것으로 생각된다. 총 균수는 숙성 초기에 급속히 증가하여 숙성 3일에 최고 수준에 도달한 후 서서히 감소했다. 숙성 온도에 따른 환원당 함량, 총 비타민 C 함량 및 총 균수의 차이는 발견되지 않았다. A군의 경우, 솔잎즙 무첨가구의 젖산균수는 숙성 9일에 최고 수준에 도달한 반면, 솔잎즙 첨가구에서는 숙성 5~9일에 최고 수준에 도달한 뒤 서서히 감소하거나 일정 수준을 유지 하였다. A군과는 달리 B군의 솔잎즙 첨가구의 젖산균수는 숙성 초기부터 증가하여 숙성 7일에 최고 수준에 도달한 후 서서히 감소하였다. 숙성 온도와 관계없이 솔잎즙 첨가 수준이 증가할수록 총 균수와 젖산균수는 감소하였다. 이상의 실험 결과들은 솔잎즙이 pH의 저하를 지연시키고 미생물의 생육을 억제함으로써 김치의 발효숙성을 지연시키는 효과를 나타내 보이고 있다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제19권3호
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• pp.47-55
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• 2014

Arthrobacter chlorophenolicus A6 possesses several monooxygenases (CphC-I, CphC-II, and CphB) that can catalyze the transformation of 4-chlorophenol (4-CP) to hydroxylated intermediates in the initial steps of substrate metabolism. The corresponding genes of the monooxygenases were cloned, and the competent cells were transformed with these recombinant plasmids. Although CphC-II and CphB were expressed as insoluble forms, CphC-I was successfully expressed as a soluble form and isolated by purification. The specific activity of the purified CphC-I was analyzed by using 4-CP, 4-chlorocatechol (4-CC), and catechol (CAT) as substrates. The specific activities for 4-CP, 4-CC, and CAT were determined to be 0.312 U/mg, 0.462 U/mg, 0.246 U/mg, respectively. The results of this study indicated that CphC-I is able to catalyze the degradation of 4-CC and CAT in addition to 4-CP, which is a primary substrate. This research is expected to provide the fundamental information for the development of an eco-friendly biochemical degradation of aromatic hydrocarbons.

• Archives of Pharmacal Research
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• 제28권11호
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• pp.1205-1212
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• 2005

2-Thiouracil-5-sulphonic acid N-(4-acetylphenyl) Amide (1) was reacted with a series of aromatic aldehydes giving chalcones 2 (Claisen-Schemidt reaction), some of these chalcones were reacted with urea and thiourea giving pyrimidine-2-one and pyrimidine-2 thione derivatives respectively of the type 3a,b and 4a,b. In addition many chalcones were reacted with hydroxylamine hydrochloride giving isoxazoline derivatives 5a,b. They could also reacted with phenylhydrazine to give pyrazoline derivatives 5a,b, chalcones also were reacted withethylcyano acetate and/or malononitryl in pyridine giving pyran derivatives 7a,c and 8a,c. In another pathway chalcones were epoxidised by $H_{2}O_{2}$ giving epoxides 9a,c which in turn were reacted with phenylhydrazine giving 4-hydroxypyrazoline derivatives 10a,c. In another reaction chalcones were reacted with ethylcyanoacetate in presence of amm.acetate giving pyridone derivatives 11a,d which could be prepared also in exellent yield from compound 1 by its reaction with certain aromatic aldehydes and ethylcyanoacetate in presence of ammonium acetate. Finally, compound 1 was reacted with semicarbazide giving semicarbazone intermediate 12 which in turn was reacted with thionyl chloride giving thiadiazole derivative 13. The biological effects of some of the new synthesized compounds were also investigated.

• Bulletin of the Korean Chemical Society
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• 제20권3호
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• pp.301-306
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• 1999

Hepatitis C virus (HCV) has been known to be an enveloped virus with a positive strand RNA genome and the major agent of the vast majority of transfusion associated cases of hepatitis. For viral replication, HCV structural proteins are first processed by host cell signal peptidases and NS2/NS3 site of the nonstructural protein is cleaved by a zinc-dependent protease NS2 with N-terminal NS3. The four remaining junctions are cleaved by a separate NS3 protease. The solution conformations of NS4B/5A, NS5A/5B substrates and NS5A/5B inhibitor have been determined by two-dimensional nuclear magnetic resonance (NMR) spectroscopy. NMR data suggested that the both NS5A/5B substrate and inhibitor appeared to have a folded tum-like conformation not only between P1 and P6 position but also C-terminal region, whereas the NS4B/5A substrate exhibited mostly extended conformation. In addition, we have found that the conformation of the NS5A/5B inhibitor slightly differs from that of NS5A/5B substrate peptide, suggesting different binding mode for NS3 protease. These findings will be of importance for designing efficient inhibitor to suppress HCV processing.

• Archives of Pharmacal Research
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• 제21권5호
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• pp.599-609
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• 1998

In search for new antitumor agents, twelve 6-aziridinylbenzimidazole derivatives were synthesized and their cytotoxicities were tested against three cancer cell lines (mouse lymphocytic leukemia P388 and B16, and human gastric carcinoma SNU-16). From 4-amino-3-nitrotoluene as the starting material, 2-(acetoxymethyl)benzimidazoles (5a-d) were obtained by Phillips reaction. These benzimidazoles were then reacted with Fremy's salt to give a mixture of three 2-(acetoxymethyl) (8a-c) and four 2-(hydroxymethyl)benzimidazole-4,7-diones (9a-d). Addition of these quinones with aziridine afforded 6-aziridinyl-2-(acetoxymethyl) (10a-c) and 6-aziridinyl-2-(hydroxymethyl)benzimidazole-4,7-diones (11a-d). Utilizing 2-(hydroxymethyl)benzimidazole-4,7-diones (9b,d), esters 10d and 13e-h were prepared by the sequential reactions of esterification and addition. The synthesized compounds show potent cytotoxicity against all of three cell lines tested. The cytotoxicities of 10a-d or 11a-d against SNU-16 were wuperior to those of 13e-h, and were equal to or slightly higher than that of mitomycin C. compounds 11a-d were slightly more cytotoxic than 10a-d in all cell lines tested.

• 한국재료학회지
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• 제14권4호
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• pp.246-250
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• 2004

We have investigated the effects of boron added to Cu film on the Cu-Ti reaction and microstructural evolution of Cu(B) alloy film during annealing of Cu(B)/Ti/$SiO_2$/Si structure. The result were compared with those of Cu(B)/$SiO_2$ structure to identify the effects of Ti glue layers on the Boron behavior and the result grain growth of Cu(B) alloy. The vacuum annealing of Cu(B)/Ti/$SiO_2$ multilayer structure allowed the diffusion of B to the Ti surface and forming $TiB_2$ compounds at the interface. The formed $TiB_2$ can act as a excellent diffusion barrier against Cu-Ti interdiffusion up to $800^{\circ}C$. Also, the resistivity was decreased to $2.3\mu$$\Omega$-cm after annealing at $800^{\circ}C$. In addition, the presence of Ti underlayer promoted the growth Cu(l11)-oriented grains and allowed for normal growth of Cu(B) film. This is in contrast with abnormal growth of randomly oriented Cu grains occurring in Cu(B)/$SiO_2$ upon annealing. The Cu(B)/Ti/$SiO_2$ structure can be implemented as an advanced metallization because it exhibits the low resistivity, high thermal stability and excellent diffusion barrier property.