• Explosives and Blasting
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• v.8 no.3
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• pp.3-13
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• 1990

First ot of all, under given condition such as bit gage of 36mm Drill bit with right class of jack-leg-experimental test carried out from two face of Bench, firing of each hole brought 90 degree Angle face and them measured length of Burden and charged ammount of powder as following. $ca=\frac{A}{SW}$ A=Activated Area A=nd i=m S=Peripheral length of charged, room Ca=Rock Coeffiecency d: di=Hole diameter When constructed subway of Seoul in 1980 the blasting works increased complaint of ground vibration, in order to prevent the damage to structures. Some empirical equations were made as follows on condition with Jackleg Drill (Bit Gage 36mm) and within 30 meter distance between blasting site and structures. $V=K(D/W)^{-n}$ N=1.60 - 1.78 K= 48 - 138 Project is one of contineous works to above a determination of empirical equation on the cautious blasting vibration with Crawler Drill (70-75mm) in long distance. $V=41(D/\sqrt[3]{W})^{-1.41}$ $30m\le{D}\le{100m}$ $V=124(D/\sqrt[3]{W})^{-1.66}$ $100m\le{D}\le{285m}$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.8
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• pp.491-495
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• 2017

We investigated solution-processed indium-zinc oxide (IZO) thin-film transistors (TFTs) by inserting a 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD) buffer layer. This buffer layer efficiently tuned the energy level between the semiconducting oxide channel and metal electrode by increasing charge extraction, thereby enhancing the overall device performance: the IZO TFT with embedded PBD layer (thickness: 5 nm; width: $2,000{\mu}m$; length: $200{\mu}m$) exhibited a field-effect mobility of $1.31cm^2V^{-1}s^{-1}$, threshold voltage of 0.12 V, subthreshold swing of $0.87V\;decade^{-1}$, and on/off current ratio of $9.28{\times}10^5$.

• Textile Coloration and Finishing
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• v.15 no.3
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• pp.127-131
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• 2003

Acrylonitrile(AN) was solution-polymerized in dimethyl sulfoxide(DMSO) and tertiary butyl alcohol(TBA) at 30, 40, $50^\circ{C}$ using a low temperature initiator, 2,2'-azobis(2,4-dimethylvaleronitrile) (ADMVN). The low temperature polymerization using ADMVN, DMSO, and TBA is to be successful in obtaining high molecular weight polyacrylonitrile(PAN) with less branches by solution polymerization. Throug a polymerization of AN in DMSO at $30^\circ{C}$, PAN having viscosity-average molecular weight$(M_v)$ of 931,000 was obtained. And then, during AN solution polymerization in DMSO and TBA using a cosolvent system the in-situ formation of microfibrillar structure has been discovered at the cosolvent composition of 24/1$(V_{DMSO}/V_{TBA})$. The simultaneous process of gelation and phase separation of long chain molecules may explain the in-situ formation of PAN fibers during polymerization.

• Nuclear Engineering and Technology
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• v.55 no.5
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• pp.1559-1566
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• 2023

This study developed a quasi-monoenergetic neutron source (QMN) for the semiconductor device's soft error rate test (SER). Quasi-monoenergetic neutrons are generated by ⁹Be(p, n)⁹B nuclear reaction with a 1 mm beryllium target and 30 MeV protons from a cyclotron. An 8 mm water in the back of the beryllium target is used for avoiding proton penetration. The neutron spectra simulated by MCNP showed that the peak energy was around 26.5 MeV. The heat flow and mechanical properties are numerically analyzed, and the safe operating conditions are therefore determined.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.3
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• pp.395-402
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• 2017

The local heat transfer and total pressure drops of developed turbulent flows in the ribbed rectangular convergent/divergent channels with ${\Lambda}/V-shaped$ ribs have been investigated experimentally. The channels have the exit hydraulic diameter ($D_{ho}$) to inlet hydraulic diameter ($D_{hi}$) ratios of 0.67 for convergence and 1.49 for divergence, respectively. The ${\Lambda}/V-shaped$ ribs with three different flow attack angles of $30^{\circ}$, $45^{\circ}$, and $60^{\circ}$ are manufactured with a fixed rib height (e) of 10 mm and the ratio of rib spacing (S) to height (e) of 10 on the walls. Thermal performances of the ribbed rectangular convergent/divergent channels are compared with the smooth straight tube under identical pumping power. The results show that the flow attack angle of $45^{\circ}$ with ${\Lambda}-shaped$ rib has the greatest thermal performance at all the Reynolds numbers studied in the convergent channel; whereas, the flow attack angle of $60^{\circ}$ with V-shaped rib has the greatest thermal performance over Reynolds number of 30,000 in the divergent channel.

• Nuclear Engineering and Technology
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• v.56 no.9
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• pp.3796-3803
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• 2024

By employing the melt-quenching technique, the ZnO-SrO-B₂O₃-PbO (ZSBP) glasses have been successfully fabricated. The derivative of Absorption Spectra Fitting (DASF) method was used to study the energy band gap (E_g) of the glasses which decreases from 3.57 eV to 3.39 eV. The structural properties have been studied using the Raman spectroscopy. The glass transition temperature (T_g) decreases with increase in concentration of the lead oxide. The current study examines the radiation shielding properties at 30.80-444 keV. The addition of PbO to the glasses resulted in a proportionate increase in the mass attenuation coefficient (MAC), suggesting a diminishing tendency in radiation transmission. At 30.80 keV, the MAC values are extremely high and range from 18.06 to 21.11 cm²/g. As density rises, the half value layer (HVL) decreases. In addition, the average HVL (${\overline{HVL}}$) decreases. The glass thickness required to reduce the radiation intensity to 90 %, 50 %, 25 %, and 10 % of its initial value is investigated at an energy of 35.80 keV. The T90 %, T50 %, T25 %, and T10 % values are 0.0020, 0.0132, 0.0264, and 0.0439 cm, respectively. The results suggest that a greater thickness of the radiation barrier is necessary to attain the necessary degree of attenuation.

• Korean Journal of Food Science and Technology
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• v.15 no.3
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• pp.220-224
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• 1983

The hydration of water, at $20^{\circ}\;30^{\circ}$ and $40^{\circ}C$ for 10-360 minutes, by the two varieties of husked barley and of naked barley which were polished to 40 and 30%, respectively, was investigated. The absorption was directly proportional to the square root of the hydration time and accounted for by the diffusion equation: 1-M = $(2/{\sqrt\pi})\;(S/V){\sqrt{Dt}}$, where 1-M is the relative moisture gain and S/V is the surface-to-volume ratio. The average diffusion coefficient (D) was given by the Arrhenius relation: D = $D_{0}\;exp\;(-Ea/RT)$, where the activation energy for both husked and naked barley was about 7.2 Kcal/mole. The average value of D for naked barley was slightly higher than that for husked barley.

• Journal of fish pathology
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• v.17 no.3
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• pp.159-169
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• 2004

Bacterial wihte enteritis ocurred by infection of V. ichthyoenteri is a devastating disease in olive flounder (Paralichthys olivaceus) hatcheries in Korea. Since white enteritis has been a problem in aquqtic industries, necessity of a rapid detection method is increased. In an attempt to develop rapid PCR method the detection of V. ichthyoenteri, we examined the 16S-23S rRNA intergenic spacer region(ISR) of V. ichthyoenteri and developed species-specific primer for V. ichthyoenteri. The intergenic spacers were amplified by primers complementary to conserved region of 16S and 23S rRNA genes. The intergenic spacer region between the 16S and 23S rRNA genes of V. ichthoenteri were investigated by PCR fragment length typing and DNA sequencing. Analysis of the ISR sequences showed that V. ichthyoenteri contains one types of polymorphic ISRs. The size of ISRs ranged 348bp length and not contains tRNA genes. Mutiple alignment of representative sequences from different Vibrio species revealed several domains of high sequence variability, and allowed to design species-specific primer for detection of Vibrio ichthyoenteri. PCR. The specific of the primer was examined using genomic DNA prepared from 19 different Vibrio species, isolated 18group Vibrio species. The results showed that the PCR reaction using species-specific primer designed in this study can be used to detect V. ichthyoenteri.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.9
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• pp.631-637
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• 2003

We have evaluated structural and electric, ferroelectric properties of PZT(30/70) thick film prepared by using 1,3-propanediol based sol-gel method on Pt/Ti/SiO$_2$/Si substrates. Rapid thermal annealing (RTA) is used to reduce the thermal stress and final furnace annealing is processed at $650^{\circ}C$. As the results of SEM analysis, we find that we get 350 nm in thickness for one coating and 1 $\mu$m for three times of coating. In the results of C-D analysis at 1 kHz, dielectric constant ($\varepsilon$$_{r}$) and dissipation factor were 886 and 0.03, respectively. C-V curve is shaped as a symmetrical butterfly. Leakage current density at 200 kV/cm is 1.23${\times}$10$^{-5}$ A/cm$^2$ and in the results of hysteresis loops measured at 150 kV/cm, the remnant polarization (P$_{r}$) and the coercive field (E$_{c}$) are 33.8 $\mu$C/cm$^2$ and 56.9 kV/cm, respectively. PZT(30/70) thick film exhibits relatively good ferroelectric, electric properties.s..

• Microbiology and Biotechnology Letters
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• v.37 no.4
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• pp.350-354
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• 2009

A Gram-negative, alginate lyase-producing bacterium was isolated from the Haeundae Coast, Korea. The isolated strain N7151-6 produced alginate lyase. The optimal temperature and pH for growth were found to be $30^{\circ}C$ and pH 8.0, respectively. This strain can be grown at the NaCl concentration of 0-7% (w/v). Analysis of 16S rDNA sequence and physiological profiling indicated that the strain N7151-6 belonged to Pseudomonas sp. The enzyme alginate lyase produced by Pseudomonas sp. N7151-6 was partially purified by ultrafiltration (MWCO= 30 kDa). The optimum pH and temperature for the activity of the purified enzyme were found to be 7.0 and $30^{\circ}C$, respectively. The enzyme was stable at the pH range of 5.0-9.0 and temperature range of $23-30^{\circ}C$. The total activity of alginate lyase produced was reached about 110 unit/L.