• Korean Journal of Agricultural Science
• /
• v.22 no.2
• /
• pp.127-133
• /
• 1995

A Series of meta and para-substituted phenyl N-methylcarbamate derivatives were synthesized and influence of substituents(X) on the molecular orbital(MO) quantities of carbonyl group, carbamylation reaction center, and insecticidal activities($pI_50$) were discussed quantitatively. From these findings, the most stable streo conformer(Z) shows that the planer phenyl group occupies vertical(${\theta}=90^{\circ}$) position on the plane of the N-methylcarbamyl group. The carbamylation mechanism was proposed that the carbamylation process of acetylcholinesterase(ACh.E) by m-methyl substituted phenyl N-methylcarbamate derivatives proceeds via hyperconjugation of m-methyl group and carbonyl oxygene protonation, theromodynamically control reaction with acidic site of ACh.E.

• Electrical & Electronic Materials
• /
• v.7 no.5
• /
• pp.403-408
• /
• 1994

Dielectric and structural properties of $Ba_{1-x}$(Z $n_{1}$3/T $a_{2}$3/) $O_{3}$+1 mol% Mn $O_{2}$ (x=0, 0.01, 0.02, 0.03, 0.04) ceramics was investigated at microwave frequencies. With $Ba_{+2}$ shortage, the sinterability and the unloaded Q( $Q_{u}$) were much improved, and the ordering in B site and the lattice distortion was greatly enhanced and the structure approached the completely ordered structure. $Q_{u}$ was strongly correlated with these factors such as ordering ratio, lattice distortion and sinterability, and had the maximum value of 7500 at x=0.01. The dielectric constant was near 30 and the temperature coefficient of the resonant frequency was 2 ppm/.deg. C at x=0.01.1.1.1.

• Transactions on Electrical and Electronic Materials
• /
• v.6 no.5
• /
• pp.202-209
• /
• 2005

Phase evolution, microstructure and the electrical properties such as $k_p$ and $Q_m$ of $Pb(Mg_{1/3}Nb_{2/3})O_3[PMN]-Pb(Mn_{1/3}Nb_{2/3})O3[PM'N]-PbZrO_3[PZ]-PbTiO_3[PT]$ quaternary system were investigated within the compositional ranges $0{\leq}y{\leq}0.125$, y+z=0.125, and $0.39{\leq}x{\leq}0.54$ of the formula $Pb_{0.97}Sr_{0.03}[Mg_{1/3}Nb_{2/3})_y\;(Mn_{1/3}Nb_{2/3})_z\;(Zr_{x}Ti_{1-x})_{1-(y+z)}]O_3$. In the case of increasing Mn/(Mg+Mn) ratio for a fixed Zr/Ti ratio of 47.5/52.5, phase relation remained unchanged but the grain size drastically decreased, and the electrical properties changed as following: both $k_P$ and $Q_m$ reached the peak values at $Mn/(Mg+Mn)\cong0.3l7$ and gradually decreased; $\varepsilon33^T$ showed a monotonic decrease; P-E hysteresis loop gradually changed to asymmetrical one, and $E_i$ increased in correspondence. With increasing Zr/Ti ratio for a fixed Mn/(Mg+Mn) ratio of 0.317, on the contrary, the cell parameter $(\alpha^2c)^{1/3}$ gradually increased, and tetragonal-rhombohedral morphotropic phase boundary appeared in the range of $51/49{\leq}Zr/Ti{\leq}54/46$. the meantime, the grain size substantially increased, and the electrical properties changed as following: $k_P$ and $\varepsilon33^T$ reached peak values at Zr/Ti=51/49 and 48/52, respectively, and then gradually decreased; change of $Q_m$ was adverse to $k_P$; both $E_C\;and\;E_i$ considerably decreased while $P_S$ moderately increased. For the system 0.125(PMN+PM'N)-0.875PZT studied, the composition Mn/(Mg+Mn)=0.3l7 and Zr/Ti=51/49 revealed some promising electrical properties for piezoelectric transformer application such as $k_P=0.58,\;Q_m\cong1000$, and $\varepsilon^T_{33}=970$, as well as dense and fine-grained microstructure.

• Journal of the Korean Mathematical Society
• /
• v.48 no.1
• /
• pp.63-82
• /
• 2011

On the hyperbolic space $D^n$, codimension-one totally geodesic foliations of class $C^k$ are classified. Except for the unique parabolic homogeneous foliation, the set of all such foliations is in one-one correspondence (up to isometry) with the set of all functions z : [0, $\pi$] $\rightarrow$ $S^{n-1}$ of class $C^{k-1}$ with z(0) = $e_1$ = z($\pi$) satisfying |z'(r)| ${\leq}1$ for all r, modulo an isometric action by O(n-1) ${\times}\mathbb{R}{\times}\mathbb{Z}_2$. Since 1-dimensional metric foliations on $D^n$ are always either homogeneous or flat (that is, their orthogonal distributions are integrable), this classifies all 1-dimensional metric foliations as well. Equations of leaves for a non-trivial family of metric foliations on $D^2$ (called "fifth-line") are found.

• Analytical Science and Technology
• /
• v.16 no.4
• /
• pp.333-338
• /
• 2003

Inclusion selectivity of a three-dimensional piperazine-ligated cyanocadmate host complex, $[Cd_x(CN)_{2x}\{HN(CH_2CH_2)_2NH\}_y]{\cdot}zG$, has been investigated for benzene (B), toluene (T), ethylbenzene (E), o- (O), m- (M), and p-xylene (P) isomers as the aromatic guest molecules. From the binary, ternary and quarternary guest mixtures of E and xylene isomer (X), the order of inclusion selectivity in the host complex is O>E>P>M. From the binary to quinary BTX mixtures, the order of preference in the complex is seen to be B>T>O${\gg}$P>M.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.23 no.5
• /
• pp.368-373
• /
• 2010

In this study, we have investigated the effects of Cr dopant on the bulk trap levels and grain boundary characteristics of $Bi_2O_3$-based ZnO (ZB) varistor using admittance spectroscopy and dielectric functions (such as $Z^*,\;Y^*,\;M^*,\;{\varepsilon}^*$, and $tan{\delta}$). Admittance spectra show more than two bulk traps of $Zn_i$ and $V_o$ probably in different ionization states in ZnO-$Bi_2O_3-Cr_2O_3$ (ZBCr) system. Three kinds of temperature-dependant activation energies ($E_{bt}'s$) were calculated as 0.11~0.14 eV of attractive coulombic center, 0.16~0.17 eV of $Zn_{\ddot{i}}$, and 0.33 eV of $V_o^{\cdot}$ as dominant bulk defects. The grain boundaries of ZBCr could be electrochemically divided into two types as a sensitive to ambient oxygen i.e. electrically active one and an oxygen-insensitive i.e. electrically inactive one. The grain boundaries were electrically single type under 460 K (equivalent circuit as parallel $R_{gb1}C_{gb1}$) but separated as double one ($R_{gb1}C_{gb1}-R_{gb2}C_{gb2}$) over 480 K. It is revealed that the dielectric functions are very useful tool to separate the overlapped bulk defect levels and to characterize the electrical properties of grain boundaries.

• Journal of Microbiology and Biotechnology
• /
• v.9 no.6
• /
• pp.811-819
• /
• 1999

The ${\beta}-CGTase$ gene of alkalophilic Bacillus firmus var. alkalophilus was cloned into E. coli using $pZErO^{TM}-2$ as a vector. The cloned gene encoded a total of 710 amino acid residues consisting of 674 amino acids of the matured protein and 36 amino acids of the signal peptide, including 20 amino acids from the lacZ gene in the vector. Although the cloned ${\beta}-CGTase$ gene did not contain the promoter and start codons, it was expressed by the lac promoter and lacZ start codon in the $pZErO^{TM}$ vector. A comparison was made with the amino acid sequence and ten other CGTases from Bacillus sp. Also, ten highly conserved regions, which are important amino acid residues in catalysis of CGTase, were identified. The lac promoter used for expression of the ${\beta}-CGTase$ gene was induced constitutively in recombinant E. coli even without IPTG possibly because of a lack of the lacI gene in both host and vector, repressing the lacZ gene in the lac operon. Its expression was catabolically repressed by glucose, however, its repression was reduced by soluble starch, mainly because of the extremely high increase of the cAMP level. ${\beta}-CGTase$ can be overproduced in the recombinant E. coli by maintaining intracellular cAMP levels mostly through the intermittent feeding of glucose during cultivation.

• Korean journal of applied entomology
• /
• v.44 no.2
• /
• pp.131-137
• /
• 2005

Seasonal occurrence of the egg parasitoid of bugs, Ooencyrtus nezarae (Hymenoptera: Encyrtidae), was monitored at soybean fields and university campus using traps baited with aggregation pheromone of bean bug, Riptortus clavatus, in Jinju, Gyeongnam province, Korea. The female O. nezarae captured at university campus in 2003 and 2004 was 317.5 and 103.4 times as many as males, respectively, and it was 12.6 times at soybean field in 2004. The female began to occur from late August, showing its peak around September 20 at soybean field in 2004. At university campus in 2003 and 2004, the female began to occur from mid or late August, and showed its peak early or mid September. At the two monitoring sites the catches of female sharply declined after October The E2HZ3H only showed attractiveness to O. nezarae, among three components of the aggregation pheromone of bean bug, (E)-2-hexenyl (Z)-3-hexenoate (E2HZ3H), (E)-2-hexenyl (E)-2-hexenoate (E2HE2H), and myristyl isobutyrate (MI). A mixture in a ratio of 20:20:10 or 16.7:16.7:16.7 of E2HZ3H:E2HE2H:MI attracted significantly more females than the mixture of 7:36:7 ratio did. This higher attractiveness of the former two blends may be attributed to the higher amounts of E2HZ3H in the blends.

• Journal of The Korean Astronomical Society
• /
• v.34 no.4
• /
• pp.247-249
• /
• 2001

The accretion disks are usually supposed symmetric to reflection on the Z=0 plane. Asymmetries in the flow are be ver-y small in the vicinity of the compact accretor. However their existence can have a important role in the case of subkeplerian accretion flows onto black holes. These flows lead to strong heating and even to the formation of shocks close to the centrifugal barrier. Large asymmetries are due to the development of the KH instability triggered by the small turbulences at the layer separating the incoming flow from the out coming shocked flow. The consequence of this phenomenon is the production of asymmetric outflows of matter and quasi periodic oscillations of the inner disk regions up and down the Z=0 plane.

• Journal of Microbiology and Biotechnology
• /
• v.16 no.7
• /
• pp.1163-1168
• /
• 2006

The recombinant plasmid pLEX2FP complements the mutation in Zoogloea ramigera 115MM1, and the complemented mutant produces an exopolysaccharide that shows higher affinity for the calcofluor dye than the exopolysaccharide from Z. ramigera 115SLR, resulting in higher fluorescence intensity under UV light. A compositional and structural analysis of the exopolysaccharide from Z. ramigera 115MM1 showed that the different fluorescent properties were due to a lower content of acetyl groups when compared with Z. ramigera 115SLR exopolysaccharide. These results were in agreement with a sequence analysis of the gene carried in the plasmid pLEX2FP, which appeared to encode an O-acyltransferase highly homologous to the 3-O-acyltransferase of Streptomyces mycarofaciens. The gene encoding the acyltransferase from Z. ramigera 115SLR was expressed as a GST-fusion protein with 70,000 daltons in E. coli.