• 분석과학
• /
• 제14권4호
• /
• pp.349-355
• /
• 2001

금속 염화물을 이용한 화학적 활성화 방법으로 페놀 수지로부터 미세기공과 증기공을 가지는 활성탄을 제조하였다. 본 연구에서 질소 흡착 데이터는 생성된 활성탄 표면의 물리적 성질을 특성화하는데 사용하였다. 표면 특성과 공동분포 분석 결과로부터, 페놀수지는 $962.3m^2/g$ 이상의 비표면적을 가지는 미세기공과 증기공을 가지는 활성탄을 생성함을 나타내었다. 이러한 동공구조를 가지는 활성탄은 금속 염화물($CdCl_2$, $CuCl_2$)의 양을 조절하여 만들어 졌으며, 동공의 발달은 금속염화물의 양이 증가함에 따라 증가함을 알 수 있었다. 열역학적인 DSC 데이터로부터, 첫 번째 발열반응의 엔탈피 변화 값(${\Delta}H$)은 금속염화물의 증가와 함께 증가하였다.

• Journal of Dairy Science and Biotechnology
• /
• 제14권2호
• /
• pp.229-245
• /
• 1996

1. CM-Sephadex C-50-120 column을 사용하여 HLF를 효과적으로 정제하였다. CM-Sepha-dex 50-120 column chromatography를 수행한 결과, HLF는 NaCl 350 mM-500 mM 사이에서 용출되었으며, 용출된 분획을 SDS-PAGE를 수행해서 단일 band를 확인하였다. Anti-HLF antibody를 이용한 Western blotting 결과 nitrocellulose paper 상에 단일 band 가 나타나므로 HLF 가 효과적으로 정제되었다는 것을 알 수 있었다. 2. Con A, PWM, PWA LPS 등의 자극원으로 단핵구와 대식세포를 자극한 다음 BLF를처리한 배 양액을 IL-1 bioassy한 결과는 Con A 33%, PMA 33%, PWM 15%, LPS 35% 이고, HLF로 처리하여 IL-1 bioassay를 한 결과는 Con A 15%, PMA 22%, PWM 10%, LPS 5%로 감소된 것으로 나타났다. 3. K-562 세포를 이용한 colony forming assay에서 BLF가 10 g/ml일 때는 30%, 30 g/ml일 때는 35%, HLF는 10 g/ml일 때는 5%,30 g/ml일 때는 30%의 저해를 나타냈다. 4. Lactoferrin의 면역증강효과를 알아보기 위하여 hapten인 VCR-BSA를 투여 한 후, 생성되는 항체생성능력을 ELISA로 비교하였다. 그 결과 HLF 및 BLF 투여군에서 대조군에 비하여 adjuvant 효과를 관찰할 수 있었다. 또한 이때 macrophage 수는 대조군에 비하여 HLF와 BLF를 투여한 군이 증가됨을 알 수 있었다. 이러한 결과로 미루어 볼 때 LF는 macrophage를 활성화 시켜서 항체 생성 능력을 증가시키는 효과가 있음을 관찰할 수 있었다. 5. Balb/c mouse의 thymus로부터 분리한 CD4- CD8- 세포를 BLF로 처리하여 24 시간 배양한 후 CB4$^-$ CD8$^-$ 세포의 분화를 측정한 결과, CD4$^-$를 CD4$^+$ 로 분화하였다. 그리고 HLF로 처리하여 24 시간 배양 후 CD4$^-$ CD8$^-$ 세포의 분화를 측정한 결과, CD4$^-$ CD8$^-$를 CD4$^+$ CD8$^+$ 로 분화하였다. 6. Lactoferrin이 T cell의 IL-2 production에 미치는 영향은 PMA 처리군, PMA+OKT3처리군, LF 단독 처리군 보다 PMA+OKT3+LF를 처리한 군이 IL-2 생성에 영향을 미쳤다. 7. Lfcin B의 단일크론항체에 의해 인식되어지는 Lfcin B의 항원결정기는 ‘QWR’로 밝혀졌다.

• 한국반도체및디스플레이장비학회:학술대회논문집
• /
• 한국반도체및디스플레이장비학회 2006년도 춘계학술대회
• /
• pp.225-231
• /
• 2006

.고상반응법 (solid state reaction)합성된 ZnS:Mn,Cu,Cl 형광체는 약 $20^{\sim}25{\mu}m$ 의 구형이고, Cubic/hexagonal 구조를 보였다. Electroluminescent device(ELD)는 실크 스크린된 형광층(ZnS:Mn,Cu,Cl)/유전체층 ($BaTiO_3$)으로 구성되었으며, 각층은 $30^{\sim}50{\mu}m,\;50^{\sim}60{\mu}m$ 정도로 도포 하였다. 100 V-400 Hz 의 구동조건에서, ELD 의 백색 발광은 450 nm, 480 nm 픽에서 각각 $Cl_s{\to}Cu^{+}\;_{Zn},\;Cl_s{\to}Cu^{2+}\;_{Zn}$ 전이에 의해 중첩된 청색, 녹색 밴드의 발광과, 580 nm 픽에서 Mn 의 $^{4}T_1{\to}^{6}A_1$ 전이에 의한 황색 밴드의 발광으로 이루어진다. Cu 농도의 증가에 따라 450 nm 의 발광 밴드의 휘도는 감소하며 580 nm 의 발광 밴드의 휘도가 증가하였고 발광 휘도가 향상되었다. 즉, 색온도가 높은 cold white(10000 K)에서 색온도가 낮은 Warm white(3000 K) 로 변한다. 이것은 450 nm 의 발광 밴드가 580 nm 의 발광 밴드에 흡수되는 에너지 전이 (Energy transfer) 현상에 기인한다. ZnS:Mn,Cu,Cl 의 Mn 1.5 wt %, Cu 2.5 wt.% 에서 최적 발광 휘도를 보이며, 100 V-400 Hz 에서 약 $12cd/cm^2$이였다.

• 한국전기전자재료학회논문지
• /
• 제11권3호
• /
• pp.242-247
• /
• 1998

In this study, we have synthesized $ZnGa_2O_4$:Mn,X powder doped with Mn, MnO, $MnF_2$ and $MnCl_2$, low voltage green emitting phosphor, in vacuum atmosphere. From PL spectra, the intensity of the emission peak, the brightness with coactivator show that $ZnGa_2O_4$:Mn,Cl > $ZnGa_2O_4$:Mn,F > $ZnGa_2O_4$:Mn,O > $ZnGa_2O_4$:Mn. These improvement of the brightness are caused by the increase of the concentration of $Mn^{2+}$ ion. In case of $ZnGa_2O_4$:Mn,Cl and ZnGa$_2$O$_4$:Mn,F, the brightness is enhanced much more, which is owed to the decrease of defect of host material. For $ZnGa_2O_4$:Mn,Cl phosphor fabricated with optimized condition, the decay time becomes short from 30 ms of the $ZnGa_2O_4$:Mn and $ZnGa_2O_4$:Mn,O to 6 ms and the brightness of CL at 1 kV, 1 mA is 60 cd/$m^2$.

• 한국약용작물학회지
• /
• 제16권4호
• /
• pp.268-272
• /
• 2008

참돌꽃 캘러스로부터 elicitor와 전구체가 salidroside 생산에 미치는 영향을 조사하였다. Elicitor로서 효모추출물, 연자성 세라믹, methyl jasmonate, jasmonic acid, ascorbic acid, 및 중금속 ($CuCl_2$/$CdCl_2$)을 캘러스 배양에 처리하였다. 효모추출물 $0.2g/\ell$농도로 처리한 결과 처리하지 않은 대조구에 보다 3.45배 증가시켰다. 사용된 elicitor 중 효모추출물이 가장 높은 salidroside 생산을 보여 가장 적합한 elicitor로 사료된다. 전구체로서 L-phenylalanine과 L-tyrosine을 배지에 첨가하여 4일 간 배양 처리하였다. Salidroside 함량분석 결과 캘러스로부터 전구체들은 유용물질 생합성에 영향을 주지는 않았다. 캘러스 배양에 첨가 처리된 L-tyrosine의 모든 농도의 경우에는 캘러스 생장뿐만 아니라 salidroside 생산을 감소시켰다.

• 한국환경농학회지
• /
• 제20권5호
• /
• pp.352-357
• /
• 2001

Cadmium (Cd) has been identified as a potential contaminant in agricultural and environmental soils. Ionic condition in the soils is an important factor to influence Cd availability. In this study, the effect of sulfate or nitrate application on Cd sorption in acidic and calcareous soils was investigated. The Cd, sulfate $(SO_4)$, and nitrate $(NO_3)$ sources were solutions of $CdCl_2$, $K_2SO_4$, and $KNO_3$, respectively. The soil-solution system pH was affected by the application of sulfate or nitrate in both acidic and calcareous soil system, but there was not clear pH difference between pre- and simultaneous applications of sulfate or nitrate (PAS/PAN or SAS/SAN). Solution ionic strength (I) values were similar between the acid and calcareous soil systems after applying the Cd even though it was significantly different in the untreated control soils. However after applying the sulfate or nitrate, the I values increased and were always higher with SAS/SAN treatments. Solution Cd concentration also increased with the application of sulfate or nitrate. However, the Cd concentration in soil solution controlled by Cd sorption in the systems was different between PAS/PAN and SAS/SAN treatments only in the calcareous soil system, but not in the acidic soil system. The difference in Cd concentration between SAS/SAN and PAS/PAN in the calcareous systems may be caused by system pH, ionic strength, complexation, and predominately, competition of the $Cd^{2-}$ with the index $K^+$ ion. Potassium ion-Cd competition in the acidic soil system may be minimized because of the abundance of hydrogen ions.

• 한국전산유체공학회:학술대회논문집
• /
• 한국전산유체공학회 2010년 춘계학술대회논문집
• /
• pp.315-319
• /
• 2010

The near wake of square section cylinders with different corner radii is studied by numerical method to investigate the influence of corner radius. Eight models, R/D=0, 0.05, 0.1, 0.15, 0.2, 0.3, 0.4, 0.5 (R is the corner radius and D is the characteristic dimension of the body) at Re=500 were studied. The numerical results of St, CD and CL at R/D=0 and R/D=0.5 were compared with experiments to prove the feasibility and also investigate the trend of flow phenomena by the various radius corners. Results indicate that, as R/D ratio is increased, the Strouha lnumber is increased, the minimum pressure point on the cylinder surface moved own stream. The calculated results shows that between R/D=0.15 to R/D=0.3 have CD and CL.

• Bulletin of the Korean Chemical Society
• /
• 제17권9호
• /
• pp.786-790
• /
• 1996

A novel optically active tetraamine ligand possessing four asymmetric centers, N,N'-bis(2(S)-aminopropyl)-1(R),2(R)-trans-1,2-diaminocyclohexane (SRRS-apchxn) and its cobalt(Ⅲ) complexes, [Co(SRRS-apchxn)X2]n+ (X=Cl-, H2O, X2=CO32-) have been synthesized. This ligand has coordinated stereospecifically to the cobalt(Ⅲ) ion to give only the Λ-uns-cis-(SS) isomer. A trans dichloro complex has been obtained via the stereospecific isomerization of Λ-uns-cis-(SS)-[Co(SRRS-apchxn)Cl2]+ to trans-(SS)-[Co(SRRS-apchxn) Cl2]+ in CH3OH-HCl medium. Ligand and complexes have been characterized by electronic absorption, 1H NMR, CD spectra, and also by elemental analysis. It is of interest that this is one of the few CoⅢ(N4)X2 type complex preparations, which produces such an uns-cis isomer with stereospecificity.

• 한국토양비료학회지
• /
• 제48권6호
• /
• pp.634-640
• /
• 2015

Chelating agents have been proposed to improve the efficiency of phytoextraction of heavy metal hyperaccumulator. However, little studies to elucidate mechanism of chelating agents to increase cadmium (Cd) extractability have been conducted. The objectives of this study were to evaluate effect of different chelating agents on Cd extractability and to determine mechanism of Cd mobilization affected by these agents. An arable soil was spiked with inorganic Cd ($CdCl_2$) to give a total Cd concentration of $20mgCdkg^{-1}$. Ethylenediaminetetraacetic acid (EDTA) and citric acid (CA) were selected and mixed with the arable soil at the rates of 0 and $5mmolkg^{-1}$. The mixture soils were incubated at $25^{\circ}C$ for 4 weeks in dark condition. Concentration of F1 Cd fractions (water soluble) significantly increased with addition of EDTA but did not changed with addition of CA. Especially; concentration of F5 Cd fractions (residual) significantly increased with addition of CA. Increase in water soluble with EDTA might be attributed to complexation of Cd and EDTA. Dissolved organic carbon concentration significantly increased with EDTA addition, but did not with CA implying that considerable amount of CA was decomposed to inorganic carbon by microorganism. Log activity of carbonate ($CO_3{^{2-}}$) which might be generated from CA increased with addition of CA. Increase in residual Cd fraction might be due to precipitation of Cd as $CdCO_3$. As a result, EDTA was effective in increasing Cd extractability, by contrast CA had significant effect in reducing Cd extractability.

• Journal of Ecology and Environment
• /
• 제29권1호
• /
• pp.61-67
• /
• 2006

Tomato (Lycopersicon esculentum Mill) seedlings exposed to various concentrations of $CdCl_2(0{\sim}100{\mu}M)$ in a nutrient solution for up to 9 days were analyzed with respect to the thiol changes and oxidative stress. The Cd exposure increased total non-protein thiols (NPT) and cysteine in both leaves and roots, total glutathione in leaves, and the ratios of oxidized glutathione (GSSG)/reduced glutathione (GSH) in both leaves and roots, but decreased the ratio of dehydroascorbate (DASA)/ascorbate(ASA) in leaves. Our results suggest that the Cd-induced GSH depletion due to thiol synthesis and oxidation alters the antioxidant activity of seedlings for $H_2O_2$, and the subsequent $H_2O_2$ accumulationand oxidative stress result in phytotoxicity.