• Journal of Ocean Engineering and Technology
• /
• v.14 no.1
• /
• pp.23-28
• /
• 2000

The fatigue crack growth behavior of the cold-rolled STS 304 steel developed for membrane material of LNG storage tank was examined experimentally at 293K, 153K and 111K. The fatigue crack growth rate(do/dN) tends to increase as the stress ratio (R) increases over the testing temperature when compared at the same stress intensity factor range($\Delta$K). The effect of R on do/dN is more explicit at low temperatures than at room temperature. The resistance of fatigue crack growth at low temperatures is higher compared with that at room temperature which is attributed to the extent of strain-induced martensitic transformation at the crack tip. The temperature dependence of fatigue crack growth resistance is gradually vanished with an increase in $\Delta$K which correlates with a decreasing fracture toughness with decreasing temperature. Fractographic examinations reveal that the differences of the fatigue crack growth characteristics between room and low temperature are mainly explained by the crack closure and the strengthening due to the martensitic transformation.

• Membrane and Water Treatment
• /
• v.4 no.1
• /
• pp.1-9
• /
• 2013

The process of electromembrane transformation of L-lysine monohydrochlorides into their zwitterionic form in four- and two-chamber electrodialysis apparatus was investigated. The process of transformation at various concentrations of lysine monohydrochloride (0.1-0.6 mol.L-1) was studied and it was established that at the optimum density of current optimal concentrations of lysine hydrochloride during electrodyalisis was in the range of 0.2-0.4 mol.L-1. It was determined that the process of total transformation was accomplished when pH of the lysine solution achieved 10. Changes of concentrations of $Cl^-$ ions and lysine diffused into the neighboring chamber were determined depending on the time. The method developed by us allows adjusting the removal coefficient of $Cl^-$ ions during transformation to a maximal value, the losses of lysine diffused into the next chamber after its return to the technological cycle being less than 1.0 %. The specific energy consumption during the process of transformation in two- and four-chamber electrodialyzers was 0.19 and 0.205 A.h.kg-1 and the current efficiency was 75.9 and 73.1 %, correspondingly. Study of the process of electromembrane transformation allowed obtaining zwitterionic form of L-lysine from L-lysine monohydrochloride with minimal reagent and energy consumption.

• Membrane Journal
• /
• v.17 no.3
• /
• pp.244-253
• /
• 2007

This research investigated the effect of a photocatalytic reaction on nanofiltration(NF) membrane fouling by natural organic matter(NOM). The photocatalytic degradation was very effective for destruction and transformation of NOM and was carried out by titanium dioxide($TiO_2$) and $TiO_2$-immobilized bead as a photocatalyst. In order to compare their phtocatalytic properties, the photocatalytic degradation of humic acid in the presence of calcium ion was used as a model reaction. After the photocatalytic degradation the membrane fouling was dramatically decreased.

• Membrane and Water Treatment
• /
• v.11 no.3
• /
• pp.223-229
• /
• 2020

Here magnetic iron oxide particles (MIOPs) were synthesized under atmospheric air and which size was controlled by regulating the flow rate of alkali addition and used for efficient removal of bovine serum albumin (BSA) from water. The MIOPs were characterized using field-emission scanning electron microscopy (FE-SEM), Fourier transformation-Infrared spectroscopy (FT-IR) and vibrating sample magnetometer (VSM). The results revealed a successful preparation of the MIOPs. The removal efficiency for BSA using MIOPs was found to be about 100% at lower concentrations (≥ 10 mg/L). The maximum adsorption of 64.7 mg/g for BSA was achieved as per the Langmuir adsorption model. In addition, microfiltration membrane for removal of BSA as model protein organic foulant is also studied. The effect of various MIOPs adsorbent sizes of 210, 680 and 1130 nm on the absorption capacity of BSA was investigated. Water permeability of the BSA integrated with the smallest size MIOPs membrane was increased by approximately 22% compared by the neat BSA membrane during dead-end filtration. Furthermore, the presence of small size MIOPs were also effective in increasing the permeate flux.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.27 no.4
• /
• pp.265-271
• /
• 2014

304L stainless steel sheets are used as a primary barrier for the insulation of membrane-type liquefied natural gas(LNG) carrier cargo containment system. 304L stainless steel is a transformation-induced-plasticity(TRIP) steel that exhibits complex material behavior, because it undergoes phase transformation during plastic deformation. Since the TRIP behavior is very important mechanical characteristics in a low-temperature environment, significant amounts of data are available in the literature. In the present study, a uniaxial tensile test for 304L stainless steel was performed to investigate nonlinear mechanical characteristics. In addition, a viscoplastic model and damage model is proposed to predict material fractures under arbitrary loads. The verification was conducted not only by a material-based comparative study involving experimental investigations, but also by a structural application to the LNG membrane of a Mark-III-type cargo containment system.

• Journal of Sensor Science and Technology
• /
• v.31 no.6
• /
• pp.366-370
• /
• 2022

A 12 ㎛ pixel-sized 360 × 240 microbolometer focal plane array (MBFPA) was fabricated using a complementary metaloxide-semiconductor (CMOS)-compatible process. To release the MBFPA membrane, an amorphous carbon layer (ACL) processed at a low temperature (<400 ℃) was deposited as a sacrificial layer. The thermal time constant of the MBFPA was improved by using serpentine legs and controlling the thickness of the SiNx layers at 110, 130, and 150 nm on the membrane, with response times of 6.13, 6.28, and 7.48 msec, respectively. Boron-doped amorphous Si (a-Si), which exhibits a high-temperature coefficient of resistance (TCR) and CMOS compatibility, was deposited on top of the membrane as an IR absorption layer to provide heat energy transformation. The structural stability of the thin SiNx membrane and serpentine legs was observed using field-emission scanning electron microscopy (FE-SEM). The fabrication yield was evaluated by measuring the resistance of a representative pixel in the array, which was in the range of 0.8-1.2 Mohm (as designed). The yields for SiNx thicknesses of SiNx at 110, 130, and 150 nm were 75, 86, and 86%, respectively.

• Journal of Biomedical Engineering Research
• /
• v.15 no.4
• /
• pp.439-446
• /
• 1994

Two-Dimensional modelling of the Cochlear biomechanics is presented in this paper. The Laplace partial differential equation which represents the fluld mechanics of the Cochlea has been transformed into two-dimensional electrical transmission line. The procedure of this transformation is explained in detail. The comparison between one and two dimensional models is also presented. This electrical modelling of the basilar membrane (BM) is clearly useful for the next approach to the further development of active elements which are essenclal in the producing of the sharp tuning of the BM. This paper shows that two-dimension model is qualitatively better than one-dimensional model both in amplitude and phase responses of the BM displacement. The present model is only for frequency response. However because the model is electrical, the two-dimensional transmission line model can be extended to time response without any difficult.

• Microbiology and Biotechnology Letters
• /
• v.18 no.3
• /
• pp.317-321
• /
• 1990

The broad-host plasmid PAM $\beta_1$ of Streptococcus faecalis DS 5 which codes for erythromycin resistance and lactose utilization was transferred into L. casei M-3 (lac-mutant) by conjugation, but was not transferred by protoplast fusion and protoplast transformation. For conjugal transfer of plasmid PAM $\beta_1$ the method of membrane filter mating was more efficient than that of agar surface mating. The rate of acid production of transconjugant C-1, C-3 was similar to L. casei YIT 9018. The proteolytic activity of transconjugant C-3 was increased 20% higher than that of wild type. Plasmid PAM $\beta_1$ was detected by a11 of the transconjugants. The transconjugants expressed lactose ulitization and erythromycin resistance.

• Membrane Journal
• /
• v.21 no.3
• /
• pp.229-235
• /
• 2011

In this study, mesoporous titania/alumina membranes were prepared by sol-gel method. Pore structure and phase composition of titania/alumina membranes could be changed by calcination temperature. The addition of alumina into titania membranes retarded anatase-to-rutile phase transformation, resulting in stabilization of pore structures. The 5 time dip-coated membrane calcined at $450^{\circ}C$ is about $10.3{\mu}m$ in thickness with an average pore size of 5 nm. Hydrogen and nitrogen permeances through the membrane were $17.1{\times}10^{-7}mol/m^2{\cdot}s{\cdot}Pa$ and $4.7{\times}10^{-7}mol/m^2{\cdot}s{\cdot}Pa$, respectively. These data were explained by the Knudsen diffusion mechanism.

• Macromolecular Research
• /
• v.17 no.8
• /
• pp.597-602
• /
• 2009

Although the existing design principle of full-sequence ionic complement is convenient for the development of peptides, it greatly constrains the exploration of peptides with other possible assembly mechanisms and different yet essential functions. Herein, a novel designed half-sequence ionic complementary peptide (referred to as P9), AC-Pro-Ser-Phe-Asn-Phe-Lys-Phe-Glu-Pro-$NH_2$, is reported. When transferred from pure water to sodium chloride solution, P9 underwent a dramatic morphological transformation from globular aggregations to nanofibers. Moreover, the rheological experiment showed that the P9 could form a hydrogel with a storage modulus of about 30 Pa even at very low peptide concentration (0.5% (wt/vol)). The P9 hydrogel formed in salt solution could recover in a period of about 1,800 sec, which is faster than that in the pure water. The data suggestcd that the half-sequence, ionic complementary peptide might be worthy of further research for its special properties.