• Journal of the Korean Society for Nondestructive Testing
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• v.16 no.3
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• pp.174-183
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• 1996

Acoustic emission(AE) response during stress corrosion cracking(SCC) of Inconel 600 alloy has been monitored to study the AE detectability of crack generation and growth by comparing the crack behavior with AE parameters processed, and to evaluate the applicability as a nondestructive evaluation(AE) by measuring the minimum crack size detectable with AE. Variously heat-treated specimens were tensioned by constant extension rate test(CERT) in various extension rate to give rise to the different SCC behavior of specimens. The AE amplitude level generated from intergranular stress-corrosion cracking(IGSCC) is higher than those from ductile fracture and mechanical deformation, which means the AE amplitude can be a significant parameter for distinguishing the An source. AE can also provide the effective means to identify the transition from the small crack initiation and formation of dominant cracks to the dominant crack growth. Minimum crack size detectable with AE is supposed to be approximately 200 to $400{\mu}m$ in length and below $100{\mu}m$ in depth. The test results show that AE technique has a capability for detecting the early stage of IGSCC growth and the potential for practical application as a NDE.

• Journal of the korean society of oceanography
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• v.34 no.1
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• pp.49-57
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• 1999

A red tide organism, Amphidinium carterae was incubated under different iron/chelator and nitrate concentrations to investigate the factors controlling the growth. The chelation capacity played a critical role in regulating the nitrate reductase (NR) activity and in vivo fluorescence of this organism. However, there was a significant difference between the NR activity and in vivo fluorescence in response to trace metals and chelator treatments. In vivo fluorescence was the highest in FeEDTA 10 ${\mu}$M treatments and the lowest in DTPA 10 ${\mu}$M treatments. This indicates that the availability of the trace metal is important in regulating the in vivo fluorescence of this photosynthetic microalgae In contrast, NR activity showed the highest values in trace metal enriched treatments, and trace metal + DTPA treatments showed fairly high NR activities. This suggests that DTPA treatment did not hinder the NR activity as much as it did in vivo fluorescence. In vivo fluorescence and NR activity increased with nitrate concentration of up to 50 ${\mu}$M and remained relatively constant or the rate of increase decreased above that concentration, indicating that initial nitrate concentration of higher than a certain level would not accelerate the growth of A. carterae. Further investigation is needed to elucidate the reason for the difference in timing sequence between the NR and in vivo fluorescence in response to different metal treatments and chelation capacity.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.30 no.4
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• pp.123-130
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• 2020

Nano seed incorporated in micro-sized 4BS (Tetrabasic lead Sulfate) seed was applied to the positive electrode active material and compared with Nano 4BS seed (NS). The dispersion of NS decreased due to the aggregation phenomenon, while the nano seed incorporated in micro-sized 4BS seed (INS) could confirm excellent dispersion. As the content of INS increased, the particle size of the active material became small and constant, which was confirmed through SEM and particle size analysis. The specific surface area for the reaction was increased and the high-rate discharge and lifetime characteristics were improved. In order to confirm the variation in particle size distribution in the plate manufacturing process, internal resistance and voltage were measured for 200 AGM lead-acid batteries, and it was confirmed that batteries quality variation decreased.

• ALGAE
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• v.29 no.1
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• pp.35-45
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• 2014

Palmaria palmata was integrated with Atlantic halibut Hippoglossus hippoglossus on a commercial farm for one year starting in November, with a temperature range of 0.4 to $19.1^{\circ}C$. The seaweed was grown in nine plastic mesh cages (each $1.25m^3$ volume) suspended in a concrete sump tank ($46m^3$) in each of three recirculating systems. Two tanks received effluent water from tanks stocked with halibut, and the third received ambient seawater serving as a control. Thalli were tumbled by continuous aeration, and held under a constant photoperiod of 16 : 8 (L : D). Palmaria stocking density was $2.95kg\;m^{-3}$ initially, increasing to $9.85kg\;m^{-3}$ after a year. Specific growth rate was highest from April to June (8.0 to $9.0^{\circ}C$), 1.1% $d^{-1}$ in the halibut effluent and 0.8% $d^{-1}$ in the control, but declined to zero or less than zero above $14^{\circ}C$. Total tissue nitrogen of Palmaria in effluent water was 4.2 to 4.4% DW from January to October, whereas tissue N in the control system declined to 3.0-3.6% DW from April to October. Tissue carbon was independent of seawater source at 39.9% DW. Estimated tank space required by Palmaria for 50% removal of the nitrogen excreted by 100 t of halibut during winter is about 29,000 to $38,000m^2$, ten times the area required for halibut culture. Fifty percent removal of carbon from the same system requires 7,200 to $9,800m^2$ cultivation area. Integration of P. palmata with Atlantic halibut is feasible below $10^{\circ}C$, but is impractical during summer months due to disintegration of thalli associated with reproductive maturation.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.816-819
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• 1992

Binary compound semiconductor InSb crystal which has direct-transition energy gap (0.17 ev) grown by vertical Bridgman method, then the electric-magnetic and optical properties of InSb crystal were surveyed. The growth rate of the crystals was 1mm/hr and the lattice constant $a_\circ$ of the grown crystal was 6.4863$\AA$. The electrical properties were examined by the Hall effect measurement with the van der Pauw method in the temperature range of 70$\sim$300K, magnetic field range of 500$\sim$10000 gauss. The undoped InSb crystal was n-type, the concentration and the electron mobility were 2$\sim$6 ${\times}$ $10^{16}$$\textrm{cm}^{-3}$ and carrier mobility was 6$\sim$2${\times}$$10^{4}$$cm^{2}$/v.sec at 300K, respectively. The carrier mobility was decreased with $T^{-1/2}$ due to the lattice scattering above 100K, and decreased by impurity scattering below100K. The magnetoresistance was increased 190% at 9000 gauss as compared with non-appliced magnetic field and the magnetoresistance was increased with increasing the magnetic field. Also, the Hall voltage was increased with increasing the magnetic field and decreasing the thickness of sample. The optical energy band gap of InSb at room temperature determined using the IR spectrometer was 0.167eV. The diffusion depth of Zn into InSb proportionally increased with the square root of diffusion time and the activation energy for Zn diffusion was 0.67eV. The temperature dependence of diffusion coefficient was $D=4.25{\times}10^{-3}$exp (-0.67/$K_BT$).

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.10
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• pp.1363-1367
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• 2005

A pedigree file of 4,738 records of a purebred flock of Muzaffarnagari sheep, maintained at Central Institute for Research on Goats (CIRG), Makhdoom, for a period of 24 years (1978 to 2001) was used to calculate inbreeding coefficients. The lambtraits studied were birth, 3, 6, 9 and 12 months weights as well as 6 and 12 months fleece yields. The lambs' and ewes' inbreeding coefficients ranged from 0 to 26.4% and 0 to 25%, respectively. The average inbreeding coefficient of lambs was higher than that of ewes in all periods as expected in a closed flock. Fluctuations in lamb and ewe inbreeding were observed in the periods under study. The percentages of animals in the higher inbred categories varied somewhat but generally were relatively constant. The mean rate of inbreeding was 0.63% per generation. The effective population size of the flock was 79.1. On average, an increase of 1% individual inbreeding significantly (p<0.05) reduced weights at birth by 0.010 kg, at 3 month by 0.048 kg, at 6 month by 0.075 kg, at 9 month by 0.129 kg and at 12 month by 0.112 kg. Ewes' inbreeding had non-significant effects on body weight at all ages. Effects of both lambs' and ewes' inbreeding had negative but non-significant effects on fleece weights at 6 and 12 months of age. Thus, inbreeding depression in lambs significantly reduced body weights from birth to 12 months of age but had a negligible effect on fleece yields.

• Journal of Microbiology and Biotechnology
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• v.26 no.3
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• pp.503-510
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• 2016

The accumulation (internal and superficial distribution) of magnesium ions (Mg²⁺) by the green freshwater microalga Chlorella vulgaris (C. vulgaris) was investigated under autotrophic culture in a stirred photobioreactor. The concentrations of the three forms of Mg²⁺ (dissolved, extracellular, and intracellular) were determined with atomic absorption spectroscopy during the course of C. vulgaris growth. The proportions of adsorbed (extracellular) and absorbed (intracellular) Mg²⁺ were quantified. The concentration of the most important pigment in algal cells, chlorophyll a, increased over time in proportion to the increase in the biomass concentration, indicating a constant chlorophyll/biomass ratio during the linear growth phase. The mean-average rate of Mg²⁺ uptake by C. vulgaris grown in a culture medium starting with 16 mg/l of Mg²⁺ concentration was measured. A clear relationship between the biomass concentration and the proportion of the Mg²⁺ removal from the medium was observed. Of the total Mg²⁺ present in the culture medium, 18% was adsorbed on the cell wall and 51% was absorbed by the biomass by the end of the experiment (765 h). Overall, 69% of the initial Mg²⁺ were found to be removed from the medium. This study supported the kinetic model based on a reversible first-order reaction for Mg²⁺ bioaccumulation in C. vulgaris, which was consistent with the experimental data.

• Membrane Journal
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• v.11 no.1
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• pp.14-21
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• 2001

Rapid backpulsing to reduce membrane fouling of hollow fiber ultrafiltration module (polyacrylonitrile with 50000 l'vlWCO, 1.4 rom OD and 0,9 mm ID) was studied with latex solutions. Values estimated by a theoretical model were compared with the ones obtained from the systems with or without backpulsing, Specific Cake resistance, time consUmt for cake growth, diffusion coefficient, and the rate constants of fnur fouling models; the complete, intermediate. standard blocking and cake filtration were calculated to obtain the theoretical values. High frequency backpulsing gave net increase of fluxes by 40~120%. Fluxes predicted by the model were in good agreement with experimental ones within 14% error bound, The optimum backpulsing strength was acquired at 20% in the ranges of 20~40% strength and the optimum frequcncv was acquired at 2 Hz in the ranges of 0.67~3 Hz.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.13 no.6
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• pp.297-303
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• 2003

Mn-Ni-Co type thin films were prepared at various conditions by a rf magnetron sputtering system. At the condition. or substrate temperature of $300^{\circ}C$ and $Ar/O_2$= 10/0, a cubic spinel phase was obtained. When oxygen was included in process gas, a cubic spinel phase was not formed even after the thermal annealing at $900^{\circ}C$. The thermistor thin film had no other elements except Mn, Ni and Co. The infrared reflection spectra of the thermistor thin films showed that the films had somewhat high reflectance for incoming infrared ray with some angle. The etch rate of the thermistor thin films was about 63nm/min at a condition of DI water : $HNO_3$: HCl = 60 : 30 : 10 vol%. The B constant and temperature coefficient of resistance of the thermistor thin films were 3500 K and -3.95 %/K, respectively. The voltage responsivity of the thermistor thin film infrared sensor was 108.5 V/W and its noise equivalent power and specific detectivity were $5.1\times 10^{-7}$ W/$Hz^{-1/2}$ and $0.2\times 10^6$cm $Hz^{1/2}$/W, respectively.

• Journal of Korea Foundry Society
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• v.31 no.6
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• pp.347-353
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• 2011

There is thixo-extrusion to form high strength aluminum alloy. But, it is a problem that grains become grain coarsening during reheating process because the alloy was exposed at high temperature. In order to solve grain growth during reheating process, calcium was added in Al-Zn-Mg alloys. Primary a grain sizes of semi-solid Al-Zn-Mg-(0, 0.4, 0.6 and 0.9, wt.%)Ca were measured with image analyzer after reheating. Measured primary a grain sizes were applied to LSW(Lifshitz-Slyozov and Wagner) equation to check the effect of Ca on grain coarsening. Coarsening rate constant K values of semi-solid Al-Zn-Mg-(0, 0.4, 0.6 and 0.9, wt.%)Ca alloys were $371\;mm^3s^{-1}$, $247\;mm^3s^{-1}$, $198\;mm^3s^{-1}$ and $166 mm^3s^{-1}$, respectively. As increasing calcium content, K value decreased which means grains are refined. Also, grains of calcium addition were more spherical than that of calcium free.