• Applied Chemistry for Engineering
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• v.29 no.3
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• pp.303-306
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• 2018

Methyl 4-formylbenzoate (MFB), a by-product of the DMT production process, which has been disposed, was used as a starting material for the synthesis of six new fluorescent whitening agent's candidates with 4,4'-di((E)-styryl)-1,1'-biphenyl skeleton attached with an aromatic ester, the same as that of the commercial product family. All candidates were synthesized by the reaction of MFB, and its derivatives with tetraethyl biphenyl-4,4'-diylbis(methylene)diphosphonate using Wittig-Horner reaction. UV spectra for all candidates were recorded and the data were used for calculating the molar absorptivity in order to confirm the usability as a fluorescent whitening agent. All of them showed overall molar extinction coefficients (log ${\varepsilon}$ 4.59~5.00) similar to those of conventional commercial products (log ${\varepsilon}$ 4.85). In particular, compounds 16 and 17 having a dimethoxyphenyl group exhibited a molar extinction coefficient superior to those of conventional commercial products, and thus a field testing for commercialization will be conducted.

• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2412-2420
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• 2018

The thermal degradation of low density polyethylene (LDPE) will accelerate the production of carbonyl groups (C=O), which can act as the induced dipoles under high voltage. In this paper, we researched the dielectric properties and space charge behavior of LDPE after thermal aging, which can help us to understand the correlation between carbonyl groups (C=O) and electrical properties of LDPE. The spectra results show that LDPE exhibit obvious thermooxidative reactions when the aging time is 35 days and the productions mainly contain carboxylic acid, carboxylic eater and carboxylic anhydride, whose amount increase with the increasing of aging time. The dielectric properties show that the real permittivity of LDPE is inversely proportional to temperature before aging and subsequently become proportional to temperature after thermal aging. Furthermore, both the real and imaginary permittivity increase sharply with the increasing of aging time. The fitting results of imaginary permittivity show that DC conductivity become more sensitive about temperature after thermal aging. On this basis, the active energies of materials calculated from DC conductivity increase first and then decrease with the increasing of aging time. In addition, the space charge results show that the heterocharges accumulated near electrodes in LDPE change to the homocharges after thermal aging and the mean volume charge density increase with the increasing of aging time. It is considered that the overlaps caused by electrical potential area is the main reason for the increase of DC conductivity.

• Journal of Astronomy and Space Sciences
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• v.21 no.4
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• pp.263-274
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• 2004

High resolution spectroscopic observations of BX And using the BOBS (Bohyunsan Optical Echelle Spectrograph) of Bohyunsan Optical Astronomical Observatory (BOAO) were performod during 26-27, Feb. 2003. From the observations, we obtained 38 line spectra of BX And which cover all phases except the phase interval between $0.^p1$ and $0.^p3$. Both methods of the CCF (Cross-Correlation Function) and BF (Broadening Function) were used to get the radial velocities of primary and secondary components. Both velocities of the primary and secondary stars were calculated with the BF method while only primary velocities were determined with the CCF. Using new radial velocity curves, the maximum radial velocities of the primary and secondary stars were obtained as $K_1=90.1km/s\;and\;K_2=196.6km/s$, respectively. New absolute dimension of BX And was deduced with the combination of our spectroscopic solution with the photometric one of Bell et al. (1990).

• Journal of the Korean Graphic Arts Communication Society
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• v.22 no.2
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• pp.179-198
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• 2004

Organic electroluminescent devices are light-emitting diodes in which the active materials consist entirely of organic materials. Recently, many fluorescent organic materials have been reported and the study on synthesis and application of new organic light-emitting materials has been demanded. This paper reports the optical and electrical characteristics of OLEDs using novel polymers containing biphenyl structure. First, Optical properties of novel light-emitting biphenyl derivatives doped with poly(9-vinyl carbazole)(PVK) and emitted blue, bluish green color, which is attributed to the overlap area between PL spectrum of host(PVK) and absorption spectra of guests(polymer). This is correspondent with F$\"{o}$rster energy transfer process in the blends. And, OLED devices were fabricated using poly (3,4-ethylenedioxy thiophene) (PEDOT) as a hole injection material and tris-(8-hydroxyquinoline) aluminum ($Alq_3$) as an electron transporting material. EL devices fabricated as ITO/PEDOT/PVK doped with biphenyl derivatives/$Alq_3$/Li:Al and I-V-L chatacteristics and emitting efficiency of EL devices were examined. Finally, the drift mobility of PVK doped with biphenyl derivatives and $Alq_3$ were measured by TOF technique varying applied electric field. EL efficiency was increased as the ratio of hole mobility of PVK doped with biphenyl derivatives and electron mobility of $Alq_3$ was close to one.

• Journal of the Korean Applied Science and Technology
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• v.7 no.2
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• pp.19-32
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• 1990

Lipid levels in the tissues of liver and intestines of O.bartrami amounted to 40.0% and 1.5%. The new compounds was found to be ethyl acylates, from a deduction of their detailed $^1H-nuclear$ magnetic resonance(NMR) and $^{13}C-NMR$ as well as infra red spectra (IR). The fatty acid composition of total lipids were mainly composed of C16:0(19.0%), C18:1(16.2%) and $C22:6{\omega}3$(15.7%), followed by C20:1(9.4%), C22:1(6.4%) and C18:0(5.4%). New compound A and B were seemed to derived from the cleavage of glycerol moieties of triglycerides by microbial activities during storage in a frozen state. Compound A contained C16:0(38.2%), C18:1(13:4%), C20:1(13.3%) and C22:1(11.7%) as major components, while compound B predominantly comprised polyunsaturated fatty acid such as $C20:5{\omega}3$ (41.2%) and $C22:6{\omega}3$(36.1%). In both compounds small amounts of odd numbered fatty acids were also detected ($3.8{\sim}2.2%$).

• Microbiology and Biotechnology Letters
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• v.10 no.3
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• pp.211-215
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• 1982

Streptomyces griseorubiginosus var. soyoensis previously identified, produced two kinds of antifungal antibiotics, trans-cinnamamide and another new substance. The latter was identified to be a new substance of tetraene family by establishment of UV, IR, NMR, mass spectra and chemical reactions and rotatively named as Tetraene KM-A. Through an antimicrobial activity test using serial agar dilution method, Tetraene KM-A showed strong growth inhibitory activity against fungi and yeasts, but not against procaryotes tested. The inhibitory action of Tetraene KM-A on fungi was remarkably ineffective when some of sterols were added to the cultural media. $LD_{50}$ of the Tetrene KM-A to mice and rats by intravenous injection were 84.3 and 90.4 mg/kg respectively. $LD_{50}$ to mice by oral feeding was 1503mg/kg.

• Earthquakes and Structures
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• v.6 no.2
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• pp.141-161
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• 2014

This article presents a new generation of empirical ground motion models for the prediction of response spectral accelerations in soil conditions, specifically developed for the Vrancea intermediate-depth seismic source. The strong ground motion database from which the ground motion prediction model is derived consists of over 800 horizontal components of acceleration recorded from nine Vrancea intermediate-depth seismic events as well as from other seventeen intermediate-depth earthquakes produced in other seismically active regions in the world. Among the main features of the new ground motion model are the prediction of spectral ordinates values (besides the prediction of the peak ground acceleration), the extension of the magnitudes range applicability, the use of consistent metrics (epicentral distance) for this type of seismic source, the extension of the distance range applicability to 300 km, the partition of total standard deviation in intra- and inter-event standard deviations and the use of a national strong ground motion database more than two times larger than in the previous studies. The results suggest that this model is an improvement of the previous generation of ground motion prediction models and can be properly employed in the analysis of the seismic hazard of Romania.

• Journal of Information Display
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• v.3 no.1
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• pp.6-10
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• 2002

We have synthesized a new green Ir(III) complex fac-tris-(3-methyl-2-phenyl pyridine)iridium(III) $Ir(mpp)_3$ and fabricated phosphorescent polymer light-emitting device using it as a triplet emissive dopant in PVK. $Ir(mpp)_3$ showed absorption centered at 388 nm corresponding to the $^1MLCT$ transition as .evidenced by its extinction coefficient of the order of $10^3{\cdot}$ From the PL and EL spectra of the $Ir(mpp)_3$ doped PVK film, the emission maximum was observed at 523 nm, due to the radiative decay from the $^3MLCT$ state to the ground state, confirming a complete energy transfer from PVK to $Ir(mpp)_3$. The methyl substitution has probably caused a red shift in the absorption and emission spectrum compared to $Ir(mpp)_3$. The device consisting of a 2 % doped PVK furnished 4.5 % external quantum efficiency at 72 $cd/m^2$ (current density of 0.45 $mA/cm^2$ and drive voltage of 13.9 V) and a peak luminance of 25,000 $cd/m^2$ at 23.4 V (494 $mA/cm^2$). This work demonstrates the impact of the presence of a methyl substituent at the 3-position of the pyridyl ring of 2-phenylpyridine on the photophysical and electroluminescence properties.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1416-1418
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• 2005

A new DCM derivative containing a phenothiazine moiety, 4-(dicyanomethylene)-2-t-butyl-6-(9-ethylphenothiazine-2- enyl)-4H-pyran (DCPTZ), has been synthesized as an orange-red fluorescent dye molecule for organic lightemitting diodes (OLEDs). EL devices with the structure of $ITO/PEDOT-PSS/{\alpha}-NPD/Alq_3:DCPTZ/Alq_3/LiF/Al$ have been fabricated with changing the doping concentration of the DCPTZ. Maximum EL spectra of the devices ranged from $580{\sim}620$ nm depending on the doping concentration of the dye molecule. An EL device with 0.5 % doping concentration showed CIE coordinate (0.51, 0.47) at luminance of 100 $cd/m^2$. White light-emitting devices with the structure of $ITO/PEDOT-PSS/{\alpha}-NPD/{\alpha}-NPD:DCPTZ/DPVBi/Alq_3/$ LiF/Al have been also fabricated. The thickness of blue light-emitting 1,4-bis(2,2- diphenylvinyl)benzene (DPVBi) layer was changed to obtain a white light-emission. A white light-emission from the device was observed when the thickness of the DPVBi layer became thicker than 10 nm.

• Journal of Hydrogen and New Energy
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• v.29 no.1
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• pp.97-104
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• 2018

3-dimensional temperature distribution of the exhaust gas of a fire flame of LPG have been measured by the constructed CT-TDLAS system. 3-Dimensional temperature distributions are measured by 2 layers of CT-TDLAS. Each layer has $8{\times}8$ laser beams implying the temperatures of 64 meshes are measured. SMART algorithm has been adopted for reconstructing the absorption coefficients on the meshes. The line strengths at 6 representative wave lengths of $H_2O$ have been used for obtaining the absorption spectra of the exhaust gas. The temperature distributions measured by the constructed CT-TDLAS have been compared with those by the thermocouples. The relative errors measured between by thermocouple and CT-TDLAS were 13% in average and 33% at maximum. The similarity of temperature distribution between by thermocouples and by CT-TDLAS has been shown at the lower layer than the upper layer implying an unstability of combustions.