• The Korean Journal of Pesticide Science
• /
• v.11 no.1
• /
• pp.8-17
• /
• 2007

Three-dimensional quantitative structure-activity relationships (3D-QSARs) on the fungicidal activity against damping-off (Pythium ultimum) with N-phenylbenzenesulfonamide and N-phenyl-2-thienylsulfonamide analogues (1-34) were studied quantitatively using CoMFA (comparative molecular field analysis) and CoMSIA (comparative molecular similarity indeces analysis) methodologies. On the whole, the statistical qualities of CoMSIA models with field fit alignment (FF1-FF5) were slightly higher than that of atom based fit alignment (AF1-AF5) but, the deviations of statistical quality between two alignments in case of CoMFA models were slightly lower. The statistical results of CoMFA and CoMSIA model showed that the optimized CoMSIA model (FF1: $r_{cv.}^2\;(q^2)=0.674$ & $r_{ncv.}^2=0.964$) for damping-off is better predictability and fitness for fungicidal activities than CoMFA model (AF5: $r_{cv.}^2\;(q^2)=0.616$ & $r_{ncv.}^2=0.930$). The fungicidal activities according to the information of the CoMSIA (FF1) model were dependence upon the electrostatic and hydrophobic field of the N-phenylbenzene sulfonamide analogues. Therefore, from the results of graphical analyses on the contour maps with CoMSIA (FF3) model, it is expected that the characters of R4-substituent on the N-phenyl ring as hydrophobic and hydrogen bond acceptor will be contributed to the fungicidal activity against damping-off.

• Applied Chemistry for Engineering
• /
• v.20 no.2
• /
• pp.195-200
• /
• 2009

To develop a crosslinker for the polyester powder coatings, $N^1,N^1,N^4,N^4$-tetrakis(hydroxyethyl)cyclohexane-1,4-dicarboxamide (Cy-${\beta}-HAA$), incorporated with a cyclohexane ring within the main chain of commercial ${\beta}-hydroxyalkylamide$ (${\beta}-HAA$), was prepared from the amidation of dimethyl trans-1,4-cyclohexanedicarboxylate and diethanolamine in the presence of $NaOCH_3$, The structure of $Cy-{\beta}-HAA$ was confirmed by its NMR, FT-IR and ESI-MS spectra. $Cy-{\beta}-HAA$ was thermally more stable than ${\beta}-HAA$. When $Cy-{\beta}-HAA$ was used as a crosslinker for the polyester powder coatings, it provided the smooth coating surface and reduced the formation of pinholes in the coating surface with comparison with ${\beta}-HAA$.

• Applied Biological Chemistry
• /
• v.39 no.2
• /
• pp.140-146
• /
• 1996

Imidacloprid and a series of the related compounds were synthesized, and influence of 3-N substituents(R) on the insecticidal activities against Brown plant hopper(Nilaparvata lugens) and Green peach aphid(Myzus persicae) were examined quantitatively from the structure-activities relationships(Shh) techniques. The results indicated that the molecular hydrophobicity$({\pi})$ and inductive substituent constant$({\sigma}^{\ast})$ of substituents(R) at 3-nitrogen position on the imidazolidine ring were important factors. Variations in the potency were parabolically related to the both constants. In case of Brown plant hopper, optimum value of ${\pi}$ constant was 0.52, whereas the value of ${\sigma}^{\ast}$ constant against Green peach aphid was 1.17, respectively. Among them, the strong electron withdrawing groups$({\sigma}^{\ast}>0)$ such as methyl and benzenesulfonyl group(7 & 8) showed lower insecticidal activity and non-substituted, 1(imidacloprid) showed the best insecticidal activity. It seems that the intramolecular associated(H-bond) form between 2-N-nitro group and 3-imid group may contribute to the higher insecticidal activity to the both sucking insects. And in aqueous solution, 1 showed higher residual activity below pH 6.0, and the half-life$(T_{1/2})$ was about 6 month at pH 7.0 $(ca.\;k_{obs.}:5{\times}10^{-8}sec.^{-1})$ and $45^{\circ}C$.

• Journal of Sensor Science and Technology
• /
• v.12 no.2
• /
• pp.72-78
• /
• 2003

To observe the effect of excitation coil pitch on the micro fluxgate magnetic sensor, two sensors are fabricated using multi layer board process and the pitch distance of excitation coil are $260\;{\mu}m$ and $520\;{\mu}m$, respectively. The fluxgate sensor consists of five PCB stack layers including one layer of magnetic core and four layers of excitation and pick-up coils. The center layer as magnetic core is made of a Co-based amorphous magnetic ribbon with extremely high DC permeability of ${\sim}100,000$ and has a rectangular-ring shape to minimize the magnetic flux leakage. Four outer layers as excitation and pick-up coils have a planar solenoid structure and are made of copper foil. In case of the fluxgate sensor having the excitation coil pitch of $260\;{\mu}m$, excellent linear response over the range of $-100\;{\mu}T$ to $+100\;{\mu}T$ is obtained with sensitivity of 780 V/T at excitation sine wave of $3V_{p_p}$ and 360 kHz. The chip size of the fabricated sensing element is $7.3\;{\times}\;5.7\;mm^2$. The very low power consumption of ${\sim}8\;mW$ is measured. This magnetic sensor is very useful for various applications such as: portable navigation systems, telematics, VR game and so on.

• Applied Chemistry for Engineering
• /
• v.27 no.5
• /
• pp.537-542
• /
• 2016

In this study, we have prepared mesophase pitch from pyrolysis fuel oil (PFO) by heterogeneous reforming process. This process was conducted by direct fluorination at various temperature and followed by the heat treatment at $390^{\circ}C$. The reformed pitch was then investigated by softening point analysis, elemental analysis, fourier-transform infrared spectroscopy, high resolution X-ray diffraction and polarization microscope analysis. Carbon contents of reformed pitch increased according to increasing the reaction temperature of fluorination, while oxygen, nitrogen and sulfur contents were completely eliminated. As the fluorination temperature increased, the creation, growth, coalescence and alignment process of mesophase spheres were observed. Also the interlayer spacing of carbon hexagonal planar structure decreased, while its crystalline size increased. In addition, aromatic ring compound contents increased by the condensation polymerization of aliphatic compound. These results can be attributed to the radical reactivity of the fluorine increased as the reaction temperature increased. It was considered that the fluorination reaction could help PFO to generate aromatic compounds, via promoting polymerization by radical reaction.

• Applied Microscopy
• /
• v.34 no.1
• /
• pp.71-81
• /
• 2004

When U. unicinctus mature oocytes were fertilized in vitro, germinal vesicle breakdown (GVBD) and meioses occurred and the zygotes entered cleavage stage. A modified pattern of spiral cleavages, suggestively based on behavior of mitotic spindles, have been observed in this work. The first and second cleavages were meridional and the third was equatorial, and then followed by repetitions of meridional-equatorial cleavage. The cleavage of the isolecithal egg were equal and holoblastic and its patterns were spiral. The anti-${\alpha}-,-{\beta}$- tubulin reactions and confocal microscopy revealed mitotic apparates tilted obliquely at each mitosis causing oblique displacements of the blastomeres. Despite isolecithal distribution of yolk, this observations implicated that tilting of mitotic apparates induced spiral cleavage and the displacements of blastomeres. However, these features would not be the typical spiral cleavage, but represented a modified pattern of known Spiralian s in the sense of the equal cleavage. During the first cleavage, heart-shaped eggs have been produced. Electron microscopies exhibited the first cleavage furrow extended with its membranous structure deeply into the cytoplasm. Contractile ring has not been observed.

• Nuclear Engineering and Technology
• /
• v.5 no.1
• /
• pp.44-54
• /
• 1973

In order to clarify an effective procedure of labelling organic chloro compounds by $^{38}$ Cl, phenyl chloro derivatives(7 kinds), chloro nitrobenzenes(6 kinds), chloro anisoles(2 kinds), chloro anilines(3 kinds), chloro toluenes(3 kinds), benzyl cholorides(4 kinds), and other comparing samples(3 kinds) were irradiated in the TRIGA Mark-II research reactor and the inorganic $^{38}$ Cl yields were compared with the irradiation times after extracting the inorganic portion with an aqueous solution of alkali. It was found that the relative change between the inorganic $^{38}$ Cl yield and the irradiadiation time depends a great deal on the state of the sample, and a solid sample gave a lower and steady inorganic yield. The inorganic $^{38}$ Cl yield was decreased in the order of phenyl chloro derivatives < chloro tol uene$^{38}$ Cl yield of homo functional compounds and the number of chlorine atoms on the benzene ring. Generally, poly chloro substituted derivatives could give a higher yield than those of less chloro substituted. The results were discussed and the feasibility of these results for labelling purpose was criticized.

• Food Science and Preservation
• /
• v.22 no.6
• /
• pp.886-892
• /
• 2015

The antimicrobial effects of ten isothiocyanates (ITCs) present in cruciferous vegetables and radish root hydrolysate were investigated against pathogenic bacteria from olive flounder. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were measured against two gram-positive bacterial strains (Streptococcus parauberis, S. iniae) and four gram-negative bacterial strains (Edwardsiella tarda, Vibrio ichthyoenteri, V. harveyi, Photobacterium damselae) by using a broth microdilution technique. The antibacterial activity of ITCs was in the order sulforaphane > sulforaphene > phenylethyl ITC > erucin > benzyl ITC > iberin > I3C > allyl ITC > phenyl ITC > hexyl ITC. The susceptibility of fish pathogens to ITCs was in the order of V. harveyi > E. tarda > P. damselae > S. parauberis > S. iniae > V. ichthyoenteri. Antimicrobial activity (MIC) of radish root hydrolysate was 0.250 mg/mL against S. iniae, 0.438 mg/mL against S. parauberis, and 0.500 mg/mL against both E. tarda and V. harveyi. The aliphatic ITCs were potent inhibitors of the growth of fish pathogens, followed by aromatic ITCs and indolyl ITC. The presence of a double bond in the chemical structure of ITCs decreased antibacterial activity, while ITCs with a thiol (-S-) group and a longer carbon chain increased antibacterial activity. These results suggest that ITCs have strong antibacterial activities and may be useful in the prevention of fish pathogens.

• Polymer(Korea)
• /
• v.30 no.6
• /
• pp.538-544
• /
• 2006

Two kinds of novel bifunctional methacrylated prepolymers (170-2MA and 631-2MA) which have similar structure with 2,2-bis[4- (2'-hynroxy-3'-methacryloyloxypropoxy)phenyl] propane (Bis-GMA) was synthesized for dental applications as an alternative to Bis-GMA containing bisphenol A that is doubtful as an endocrine disrupter. The organic matrices were prepared by mixing a diluent and/or a monomer with the synthesized methacrylated prepolymers. The yield, viscosity, and chemical structures of the prepolymers and the physical and methanical properties of the organic matrices were evaluated. The yields of the prepolymers synthesized through a ring-opening reaction of epoxy compound and methacrylic acid were above 90% and the viscosities of the prepolymers were much lower than that of the Bis-GMA control. From the results of $^1H-NMR$ and FTIR analyses, the chemical structures of the prepolymers were similar to that of Bis-GMA. In addition, the curing time, poly-merization shrinkage, photoconversion, polymerization depth, and compressive strength of the organic matrices formulated with 170-2MA and 631-2MA prepolymers exhibited comparable to or better than those of the existing Bis-GMA-based one. These results suggest that the novel methacrylated prepolymers which have no endocrine disrupter can be an alternative to Bis-GMA and be applicable to dental polymer materials.

• Fire Science and Engineering
• /
• v.30 no.5
• /
• pp.67-73
• /
• 2016

This paper examined the structure, fire resistance of brass fittings type CSST employed in gas appliances and the reliability verification. Brass fittings of type CSST consisted of cladding, tubing, nut, clamp ring, socket, and ball valve. The applicable JIA standard regulates the maximum working pressure to be 4.2 kPa, which is the highest pressure of the relevant standards and the KS D 3625 stipulates the maximum pressure to be 3.24 kPa. With a normal product, the average resistance within the confidence interval was found to be $7.36m{\Omega}$. The average resistance within the confidence interval was $6.67m{\Omega}$ after the fire resistance tests. The analysis indicated that the AD was 1.584 and the standard deviation was 0.3972 with respect of a normal product. Compared to the normal product, however, the damaged product after the fire resistance test showed better features, such as an AD of 1.145 and a standard deviation of 0.2467. Moreover, the average resistance of the normal product was $7.359m{\Omega}$ and the standard deviation in histogram analysis was 0.3972. The average resistance of the damaged product after the fire resistance test in the histogram was $6.67m{\Omega}$ and the standard deviation was 0.2467.