• Journal of the Chungcheong Mathematical Society
• /
• v.7 no.1
• /
• pp.117-122
• /
• 1994

In this paper we show that if {$H_n$} is a continuous strong higher derivation of order n on an ultraprime Banach algebra with a constant c, then $c||H_1||^2{\leq}4||H_2||$ and for each $1{\leq}l$ < n $$c^2||H_1||\;||H_{n-l}{\leq}6||H_n||+\frac{3}{2}\sum_{\array{i+j+k=n\\i,j,k{\geq}1}}||H_i||\;||H_j||\;||H_k||+\frac{3}{2}\sum_{\array{i+k=n\\i{\neq}l,\;n-1}}||H_i||\;||H_k|| $$ and for a strong higher derivation {$H_n$} of order n on a prime ring A we also show that if [$H_n$(x),x]=0 for all $x{\in}A$ and for every $n{\geq}1$, then A is commutative or $H_n=0$ for every $n{\geq}1$.

• Advances in Energy Research
• /
• v.4 no.2
• /
• pp.177-187
• /
• 2016

Ammonia borane $NH_3BH_3$ solubilized in organic solvent is a potential liquid-state chemical hydrogen storage material. In this study, metal acetylacetonates like $Fe(O_2C_5H_7)_3$, $Co(O_2C_5H_7)_2$, $Ni(O_2C_5H_7)_2$, $Pd(O_2C_5H_7)_2$, $Pt(O_2C_5H_7)_2$ and $Ru(O_2C_5H_7)_3$ are considered for assisting dehydrocoupling of ammonia borane in diglyme (0.135 M) at $50^{\circ}C$. The molar ratio between ammonia borane and metal acetylacetonate is fixed at 100. A protocol for the separation of the soluble and insoluble fractions present in the slurry is proposed; it consists in using acetonitrile to make the precipitation of metal-based compounds easier and to solubilize boron-based intermediates/products. The nature of the metal does not affect the dehydrocoupling mechanisms, the $^{11}B\{^1H\}$ NMR spectra showing the formation of the same reaction intermediates. The aforementioned metal acetylacetonates do mainly have effect on the kinetics of dehydrocoupling. Dehydrocoupling takes place heterogeneously and dehydrogenation of ammonia borane in these conditions leads to the formation of polyborazylene via intermediates like e.g., B-(cyclodiborazanyl) amine-borane and borazine. Our main results are reported and discussed herein.

• Journal of the Korean Electrochemical Society
• /
• v.11 no.4
• /
• pp.304-308
• /
• 2008

Noble Poly (lithium 2-acrylamido-2-methyl propane sulfonate) and its copolymer with N-vinyl formamide based on trihexyl (tetradecyl) phosphonium acetate [$(C_6H_{13})_3$ P ($C_{14}H_{29}$) $CH_3COO$; $P_{66614}$ $CH_3COO$] and trihexyl (tetradecyl)phosphonium bis(trifluoromethane sulfonyl) amide ([$(C_6H_{13})_3P(C_{14}H_{29})$] [TFSA];$P_{66614}TFSA$) were prepared and analyzed to determine their characteristics and properties. The ionic conductivity of a copolymer based $P_{66614}TFSA$ ionic liquid system exhibits a higher conductivity ($8.9{\times}10^{-5}Scm^{-1}$) than that of a copolymer based $P_{66614}CH_3COO$ system ($1.57{\times}10^{-5}Scm^{-1})$. The charge on the TFSA anion is spread very diffusely through the S-N-S core and particularly in the trifluoromethane groups, and this diffusion results in a decreased interaction between the cation and the anion. The viscosity of $P_{66614}TFSA$ (39 cP at 343 K) and $P_{66614}CH_3COO$ (124 cP at 343 K), which is very hydrophobic, was fairly high. High viscosity leads to a slow rate of diffusion of redox species. The ionic conductivity of copolymer of a phosphonium ionic liquid system also exhibits higher conductivity than that of a homopolymer system. Phosphonium ionic liquids were thermally stable at temperatures up to $400^{\circ}C$.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.19 no.2
• /
• pp.187-196
• /
• 2021

Chemical equilibrium calculations for multicomponent aqueous systems involving the reductive dissolution of magnetite (Fe₃O₄) with oxalic acid (H₂C₂O₄) were performed using the HSC Chemistry® version 9. They were conducted with an aqueous solution model based on the Pitzer's approach of one molality aqueous solution. The change in the amounts and activity coefficients of species and ions involved in the reactions as well as the solution pH at equilibrium was calculated while changing the amounts of raw materials (Fe₃O₄ and H₂C₂O₄) and the system temperature from 25℃ to 125℃. In particular, the conditions under which Fe₃O₄ is completely dissolved at high temperatures were determined by varying the raw amount of H₂C₂O₄ and the temperature for a given raw amount of Fe₃O₄ fed into the aqueous solution. When the raw amount of H₂C₂O₄ added was small for a given raw amount of Fe₃O₄, no undissolved Fe₃O₄ was present in the solution and the pH of the solution increased significantly. The formation of ferrous oxalate complex (FeC₂O₄) was observed. The equilibrium amount of FeC₂O₄ decreased as the raw amount of H₂C₂O₄ increased.

• Journal of Surface Science and Engineering
• /
• v.29 no.6
• /
• pp.797-802
• /
• 1996

Hydrogenated amorphous silicon carbide (a-SiC:H) films have been deposited on unheated substrates by low frequency (50Hz) plasma using $SiH_4+CH_4+H_2$ gas mixtures. Deposition rate, refractive index, optical band gap, Vickers hardness and IR spectrum of the deposited a -SiC:H films have been measured for various rations of gas flow rates k(=$CH_4/SiH_4$, 0.5k4) with a constant $H_2$ flow rate (100sccm). As k increases, the deposition rate of the a-SiC:H films increases up to the maximum value of about 220nm/h at k=2.5, and then it decreases. The refractive index of the films was 2.6 for k=2.5, while the optical band gap of the films was 3.3eV for k=2.2. The maximum value of Vickers hardness of the films was 1500Hv at k=1. The infrared transmission measurement shows that the films contain both Si-C and Si-$CH_3$ bonds.

• Applied Biological Chemistry
• /
• v.39 no.1
• /
• pp.60-66
• /
• 1996

To investigate a possible application of three strains of lactic acid bacteria(strain No. 49. No. 61. No. 75) from kimchi in milk fermentation industry, the optimal condition for production of intracellular ${\beta}-galactosidase$ from Lactobacillus(L.) plantarum and its enzymatic properties were examined. The preferable carbon source of the medium for strain No. 49 in production of ${\beta}-galactosidase$ was MRS broth with 1.0% lactose instead of dextrose of pH 65. for strain No. 75 with 1.0% galactose and for strain No. 61 with 3.0% lactose at pH 7.5, respectively. The maximum enzyme production from strain No. 49, No. 75 was observed after 48 hours culture at $30^{\circ}C$ in a medium containing the appropriate carbon source, from strain No. 61 after 48 hours culture at room temperature. The optimum temperature for ${\beta}-galactosidase$ activity from L. plantarum was $60^{\circ}C$ for strain No. 49, $37^{\circ}C$ for strain No. 61 and $50^{\circ}C$ for strain No. 75, respectively. The heat stability of enzyme activities for all three strains remained 90% at $45^{\circ}C$. The optimal pH was pH 6.5 and enzyme activities were most stable at pH for all three bacteria.

• Korean Journal of Materials Research
• /
• v.7 no.8
• /
• pp.654-659
• /
• 1997

HMDS[Si$_{2}$(CH$_{3}$)$_{6}$]단일 선구체를 이용하여 화학증착 방법으로 성장된 3C-SiC/Si(001) 이종접합박막의 특성을 XRD, 라만 스펙트럼 및 투과전자현미경(TEM)등을 이용하여 조사하였으며 시판되고 있는 상용 3C-SiC/Si 시편을 같은 방법으로 분석하여 특성을 비교검토하였다. $C_{3}$H$_{8}$-SiH$_{4}$-H$_{2}$혼합가스를 선구체로 이용하여 5$\mu\textrm{m}$두께로 성장된 상용 3C-SiC/Si 이종접합박막 시료의 XRD스펙트럼에서는 강한 3C-SiC(002)피크 만이 관찰되었으며, 라만 스펙트럼의 LO피크는 970nm$^{-1}$ 정도에서 강하게 나타났다. TEM 관찰 결과 다수의 전위, 쌍정, 적층결함 및 APB와 같은 결정결함들이 3C-SiC/Si 계면 근처에 집중적으로 분포되어 있었으며 성장된 박막은 단결정임을 확인할 수 있었다. 선구체로 HMDS를 사용하여 0.3$\mu\textrm{m}$ 및 2$\mu\textrm{m}$ 두께로 성장시킨 3C-SiC/Si 박막 시료의 XRD 스펙트럼은 다소 완만한 3C-SiC(002) 피크와 함께 3C-SiC(111)피크가 관찰되었으며, TEM으로 확인한 결과 소경각 결정립들이 약 5˚-10˚ 정도 방위차를 가지고 성장하여 기둥구조(columnar structure)를 이루고 있기 때문임을 알 수 있었다. 라만 스펙트럼 분석 결과 박막의 LO 피크가 967-969nm$^{-1}$정도로 다소 낮은 wavenumber쪽으로 이동되어 박막 내에 상당한 응력이 존재함을 확인할 수 있었다. 이와 같은 HMDS 3C-SiC박막의 특성은 성장 온도가 낮고 박막 성장용 가스로 사용한 HMDS 선구체에서 탄소가 과잉으로 공급되기 때문으로 제안되었다.다.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2002.02a
• /
• pp.168-170
• /
• 2002

Magnetization studies were conducted on a single crystal of $YNi_{2}$$B_{2}$C superconductor. The 17 mg crystal was studied at temperatures T from above $T_{c}$ (15.5 K) to 3 K, in the magnetic fields H // c-axis up to 6 tesla. The crystal exhibited little magnetic irreversibility, with a critical current density $CO_{3}$ ~ $10^{-4}$ $\times$ $CO_{3}$, the depairing current density. Near $T_{c}$, the equilibrium magnetization M was London-like with M $\infty$ In(H). The upper critical field $H_{c2}$ of the single crystal $YNi_{2}$$B_{2}$C was estimated by the several alternative approaches such as standard London limit, Ginzburg-Landau, and Abrikosov relations. The estimated $H_{c2}$values agree relatively well with each other approaches.

• Applied Biological Chemistry
• /
• v.7
• /
• pp.45-52
• /
• 1966

This study was carried out to determine how the water soluble, the available $P_2O_5$ and urea-N would change in the course of time, when the mixtures of calcium superphosphate and urea with lime for fertilizer which occurred in Korea and largely contained calcium carbonate were made. Three kinds of materials, i. e., calcium superphosphate, urea and lime for fertilizer were used in this study. Three kinds of mixed fertilizer, i. e., A, B and C were made up by mixing these materials to satisfy the following formula. $$1)\;Ca(H_2PO_4)_2+CaCO_3+CO(NH_2)_2{\rightarrow}$$$$Ca_2H_2(PO_4)+H_2CO_3+NH_3$$ $$2)\;Ca(H_2PO_4)_2+CaCO_3+CO(NH_2)_2{\rightarrow}$$$$Ca_3(PO_4)_2+H_2CO_3+NH_3$$ $$3)\;Ca(H_2PO_4)_2+CaCO_3+CO(NH_2)_2{\rightarrow}$$$$Ca_3(PO_4)_2+H_2CO_3+CaCO_3+NH_3$$ A,B and C were placed in desiccators respectively a six month period. During the time of storage, the water soluble, the available phosphoric acid and urea-N were measured once a month, seven times with the control measurement. The results may be summarized as follows. 1. None of A, B and C showed any change in the urea-N with the lapse of time. This fact indicated that the combination of calcium superphosphate and urea with lime for fertilizer was not unfavourable. 2. A, B and C decreased in the amount of water soluble $P_2O_5$ with the passage of time. This fact indicated that the mixing of calcium superphosphate and urea with lime for fertilizer was unfeasible. 3. The available $P_2O_5$ in any of A,B and C did not undergo a change as time went by. This fact suggested that the combination of calcium superphate and urea with lime for fertilizer was favourable.

• YAKHAK HOEJI
• /
• v.45 no.2
• /
• pp.180-189
• /
• 2001

We have reported that water-extracted Korean mistletoe (KM-110) had various biological activities such as antitumor and immunomodulatory activity, and the pectin fraction (KML-C) of the extract was one of major factors related to its biological functions. In this paper, we produced murine monoclonal antibody (mAb) against KML-C. The cAbs obtained were largely classified into two groups according to specificity to KML-C and ML-I, a pectin from European mistletoe. One group mAbs (9H7-D10 and 3C2-lH4) strongly reacted with KML-C, but not ML-I. In contrast, another group cAbs (8Bll-2C5, BE12-3E9 and 5E10-Fl) reacted with both KML-C and ML-1. The subisotypes of these mobs were shown to be IgGl (9H7-lD10, 3C2-lH4 and 8Bll-2C5) or IgM (8E12-3E9 and 5E10-Fl). To develop an assay system for determination of the amount of KML-C, we established the sandwich ELISA (enzyme-linked immunosorbent assay) method using these mAbs and horse radish peroxidase (HRP)-labelled cAbs. In various combinations of the cAbs for coated antibody and detection antibody, the sandwich ELISA quantitatively detected KML-C, showing the detection limit ranging from 7-5,000 ng/ml. Especially reproducibility (C.V) of the sandwich ELISA, in which 8E12-3E9 was used for coating antibody and 8Bll-2C5-HRP for detection antibody, was 4.59-5.83 in intra assay, and 3.9-9.4 in inter assay.