• Journal of Korean Society of Environmental Engineers
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• v.22 no.3
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• pp.587-595
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• 2000

The most problems of domestic sewage for BNR(Biological Nutrients Removal) process are deficiency of carbon source and low C/N ratio. Primary sludge fermentation is seemed to be one of the best solutions producing biodegradable organic substrates. Soluble organic materials from sludge fermentation are mainly SCFAs(Short-Chain Fatty Acids) with 2~5 carbon atoms. In this research, it was attempted to apply $A_2/O$ process with the side-stream acid fermenter to improve the nutrients removal efficiency. The result showed that proper SCFAs production is about 3.000mg/L with SRT of 4~5 days. SCFAs yield of approximately 0.10~0.16 mg SCFAs(as COD) per mg of primary sludge(as COD) were achieved. The ratio of acetic. propionic. butyric and valerie acid were 1, 0.7, 0.5 and 0.6. Significant improvements of nutrients removal over 70% in BNR process were observed. thus will reduce the demand for chemical dosing to increase nutrients removal efficiency. When the fermentate was entered $A_2/O$ process, the ratio of phosphate release to substrate uptake amounts to $0.34gPO_4-Pg^{-1}COD$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.216-221
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• 2017

Reducing optical reflection in the visible light range, in order to increase the share of transmitted light and avoid the formation of ghost images in imaging, is important for polymer lens applications. In this study, polymer lenses with refractive indices of n=1.56, 1.60, and 1.67 were fabricated by the injection-molding method with a polymer lens monomer, dibutyltin dichloride as the catalyst and an alkyl phosphoric ester as the release agent. To investigate their anti-reflection (AR) effects, various AR coating structures, viz. a multi-layer AR coating structure, tri-layer AR coating structure with a discrete approximation Gaussian gradient-index profile, and tri-layer AR coating structure with a quarter-wavelength approximation, were designed and coated on the polymer lens by an E-beam evaporation system. The optical properties of the polymer lenses were characterized by UV-visible spectrometry. The material properties of the thin films, refractive index and surface roughness, were analyzed by ellipsometry and AFM, respectively. The most effective AR coating structure of the polymer lens with low refractive index, n=1.56, was the both side coating of multi-layer AR coating structure. However, both side coating of the tri-layered discrete approximation Gaussian gradient-index profile AR coating structure gave comparable results to the both side coating of the multi-layer AR coating structure for the polymer lens with a high refractive index of n=1.67.

• Polymer(Korea)
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• v.36 no.3
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• pp.344-350
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• 2012

New pressure sensitive adhesives (PSAs) for polarizer film were prepared by electron beam (e-beam) radiation to acrylic copolymers, and their adhesive properties were investigated. The acrylic copolymers were synthesized by free radical polymerization of $n$-butylacrylate (BA), 2-hydroxyethyl methacrylate (HEMA), and acrylic acid (AA). The acrylic copolymers were coated on PET release films to a thickness of 25 ${\mu}m$, laminated to polarizer films, and then radiated with e-beam at room temperature. Gel fractions of all the acrylic copolymers after e-beam radiation at 50 kGy were higher than 93%, and their crosslinking densities were increased with increasing the content of HEMA units. PSA prepared by e-beam radiation of acrylic copolymer synthesized with a feed ratio of BA/HEMA/AA = 89.5/10/0.5 (w/w/w) at a dose of 50 kGy exhibited the best adhesion performances in terms of peel strength, creep resistance, durability and reliability, and light leakage. It is expected that the preparation method of PSAs via e-beam irradiation will improve the producibility and workability of polarizer film for liquid crystal display.

• Journal of the Korean Vacuum Society
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• v.9 no.2
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• pp.155-161
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• 2000

BN films composed of c-BN(70%) and h-BN(30%) phases have been synthesized by the ion beam assisted deposition (IBAD) process and stabilized by post-annealing. Boron was e-beam evaporated at 1.2 $\AA$/sec and nitrogen was ionized and accelerated at about 100 eV by the end-hall type ion gun. Substrates were negatively biased by DC 400 and 500 V, respectively, and heated at $700^{\circ}C$. Synthesized BN films were in-situ post-annealed at 700 or $800^{\circ}C$, respectively, for 1 hr without breaking vacuum. BN films without post-annealing were peeled off from substrates immediately when they were exposed to the air while those with post-annealing at $800^{\circ}C$ were stabilized. Post annealing reduced the film stress from 4.9 GPa to 3.4 GPa, but no considerable stress release in the c-BN phase was observed, contrary to previous reports that the stress relaxation in the c-BN phase is the main mechanism for the stabilization. Structural and chemical relaxation of non c-BN phase is supposed to be responsible for the film stress reduction and, in turn, stabilization, especially when the c-Bn content of the film is not high.

• Clean Technology
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• v.17 no.2
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• pp.85-96
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• 2011

Self-healing materials are a class of smart materials that have the structurally incorporated ability to repair damage caused by mechanical usage over time. A material (polymers, ceramics, metals, etc.) that can intrinsically correct damage caused by normal usage could lower production costs of a number of different industrial processes through longer part lifetime, reduction of inefficiency over time caused by degradation, as well as prevent costs incurred by material failure. The recent announcement from Nissan on the commercial release of scratch healing paints for use on car bodies has gained public interest on such a wonderful property of materials. This article is a second part of healing materials dealing with inorganic engineering materials such as metals, ceramics, and concrete. The healing mechanisms developed for the inorganic materials are to be discussed with the future prospect.

• The Korean Journal of Food And Nutrition
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• v.30 no.3
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• pp.591-598
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• 2017

To prolong the shelf-life of strawberry, samples were treated with gel packs containing slow-released chlorine dioxide($ClO_2$) gas at 3~7 ppm for 6 days at room temperature. The weight loss and decay ratio as well as changes in pH, color and texture properties of the treated samples were investigated. The weight of the control and $ClO_2$ gas treated samples decreased slightly, but the weight of the control changed faster than those of the $ClO_2$ gas treated samples during the storage period. The decay ratio of control was higher than those of the $ClO_2$ gas treatments since 4 days of storage. The pH and acidity in the control and in the $ClO_2$ gas treated samples were no differences during storage period. The lightness of strawberry decreased during storage, but there was no difference in lightness among the treatments even when storage time was extended. The redness and yellowness of the control showed higher change than those of the $ClO_2$ gas treatments during 6 days. The firmness of the control changed more rapidly than those of the $ClO_2$ gas treatments during 6 days. Especially, the samples treated 3 and 5 ppm $ClO_2$ gas were the least changed. And the scores for appearance, firmness and overall acceptance control and 7 ppm $ClO_2$ gas treatment decreased more rapidly than those of 3 and 5 ppm treatment.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.3
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• pp.1519-1529
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• 2016

Background: Matrix metalloproteinase -2 (gelatinase-A, Mr 72,000 type IV collagenase, MMP-2) and -9 (gelatinase-B, Mr 92,000 type IV collagenase, MMP-9) are key molecules that play roles in tumor growth, invasion, tissue remodeling, metastasis and stem-cell regulation by digesting extracellular matrix barriers. MMP-2 and -9 are well known to impact on solid cancer susceptibility, whereas, in hematological malignancies, a paucity of data is available to resolve the function of these regulatory molecules in bone marrow mononuclear cells (BM-MNCs) and stromal cells of myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). Objectives: The present study aimed to investigate mRNA expression and gelatinase A and B secretion from BM-MNCs in vitro and genotypic associations of MMP-2 (-1306 C/T; rs243865), MMP-9 (-1562 C/T; rs3918242), tissue inhibitor of metalloproteinase -1 (TIMP-1) (372T/C; rs4898, Exon 5) and TIMP-2 (-418G/C; rs8179090) in MDS and AML. Results: The study covered cases of confirmed MDS (n=50), AML (n=32) and healthy controls (n=110). MMP-9 mRNA expression revealed 2 fold increased expression in MDS-RAEB II and 2.5 fold in AML M-4 (60-70% blasts). Secretion of gelatinase-B also revealed the MMP-9 mRNA expression and ELISA data also supported these data. We noted that those patients having more blast crises presented with more secretion of MMP-9 and its mRNA expression. In contrast MMP-9 (-1562 C/T) showed significant polymorphic associations in MDS (p<0.02) and AML (p<0.02). MMP-9 mRNA expression of C/T and T/T genotypes were 1.5 and 2.5 fold increased in MDS and AML respectively. In AML, MMP-2 C/T and T/T genotypes showed 2.0 fold mRNA expression. Only MMP-9 (-1306 C/T) showed significant 4 fold (p<0.001) increased risk with chemical and x-ray exposed MDS, while tobacco and cigarette smokers have 3 fold (p<0.04) risk in AML. Conclusions: In view of our results, MMP-9 revealed synergistic secretion and expression in blast crises of MDS and AML with 'gene' polymorphic effects and is significantly associated with increased risk with tobacco, cigarette and environmental exposure. Release and secretion of these enzymes may influence hematopoietic cell behavior and may be important in the clinical point of view. It may offer valuable tools for diagnosis and prognosis, as well as possible targets for the treatments.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.344-344
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• 2017

The glycoprotein known as glomalin-related soil protein (GRSP) is abundantly produced on the hyphae and spores of arbuscular mycorrhizal fungi (AMF) in soil and roots. GRSP play a decisive role in the soil aggregation, but GRSP was also sensitive to agricultural managements. Thus, our objectives were to assess the effect of different cover crop incorporation on the GRSP content in soil and growth of subsequent soybean and maize. Pot experiments with the incorporation of four cover crops were set up. The same amount (666g) of aboveground plant parts of wheat (AMF host), hairy vetch (AMF host), mustard (non-host) and rapeseed (non-host) was separately incorporated into soils. The aboveground plant parts and roots of soybean and maize were grown in each incorporated pots and sampled at 6 and 9 weeks after sowing. Our results showed that the different cover crops incorporation affected soil biological and chemical properties such as EC, $NO_3-N$ content, ${\beta}-glucosidase$ activity, alkaline phosphatase (ALP) activity and GRSP content. The soil EC and $NO_3-N$ content in the hairy vetch, mustard and rapeseed was higher compared to the wheat. The ${\beta}-glucosidase$ activity in the wheat and hairy vetch was significantly higher than that in the mustard and rapeseed, and the ALP activity in the wheat was significantly higher than that in the hairy vetch, mustard, and rapeseed. The GRSP content in the mustard and rapeseed was significantly lower than that of the hairy vetch and wheat. Moreover, The top dry weight and leaf area of soybean and maize in the hairy vetch at 6 weeks were significantly higher compared to the other treatments. Our results indicated that the incorporation of mustard and rapeseed may cause indirectly the decrease of GRSP content and soil enzyme activity in soil. One possible explanation for the decrease of GRSP in non-AMF host crop treatments may be the decrease of AMF density in the soil. AMF are not able to form a symbiotic relationship with Brassicaceae roots due to the release of anti-fungal compounds. This means the AMF may not be able to produce GRSP in the soil. However, the differences in the benefit of cover crop incorporation were shown only by a pot experiment. Comparative investigations of crop residue managements would be applied to both pot experiment and field study to clarify a better selection of cover crops in rotation to encourage GRSP production.

• Journal of the Korean Institute of Gas
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• v.23 no.6
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• pp.1-7
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• 2019

Most oil refineries and chemical plants have flare systems designed to mitigate pressure rises in process facilities in case of emergencies that require the release of large amounts of gas due to sudden process shutdowns such as power outages. However, the rise of the flame of the flare system causes civil complaints from residents around the factory due to visible pollution, and economic loss occurs in the company, which requires constant management. In this study, two items were diagnosed and analyzed in order to derive the optimal operation method of flare system. First, to detect the cause of the rise in flame height, the acoustic leak detector was used to check gas leaks in safety valves and pressure control valves. Second, to identify the cause of flame instability, the pulsation phenomenon was diagnosed through the CFD simulation and modeling experiments of the sealing drum. By confirming the leak at 4.3% of the safety valve and 10% of the pressure control valve, the cause of abnormal sparking was derived. The information presented in this study can be easily applied to any company that has a flare system, and is expected to prevent complaints and product loss.

• Archives of Plastic Surgery
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• v.32 no.1
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• pp.85-92
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• 2005

Botulinum toxin type A is widely used for anti-wrinkling therapy, and correction of the square face. The toxin ultimately prevent the release of membrane-bound acetylcholine at the neuromuscular junction of striated muscles and thus produce chemical denervation and paralysis of the muscles. Our purpose of study is to know if application of botulinum toxin type A on calf reduction is effective, how much dosage is effective, and what are the possible complications. We reviewed data of 30 consecutive patients subjected to calf reduction in Dong-A University Hospital from February 2003 to April 2003. We injected normal saline 2cc on both calves region in 15 control group patients, and the other patients was divided 3 group. Group 1, Group 2, Group 3 was injected 50U, 100U, 150U botulinum toxin A on each calf region and followed up for 6 month. Maximal circumference of calf was not changed in the control group but an average of 0.7 cm reduction was noted in group 1, average 1.34 cm(right calf) and 1.26cm(left calf) in group 2, average 1.44cm(right calf) and 1.58cm(left calf) in group 3. Maximal area of calf was not changed in the control group but average reduction of 12.5%(right calf) and 12.7%(left calf) was obtained in group 1, average 19.4% (right calf) and 19.9%(left calf) in group 2, average 24.8%(right calf) and 21.07%(left calf) in group 3, as measured on CAT scan. Total fat amount and fat amount in the lower extremity was no change in all the groups, but lean body mass was decreased average 1.27%(right calf) and 1.15%(left calf) in group 1, average 3.47%(right calf) and 2.98%(left calf) in group 2, average 3.58%(right calf) and 3.95%(left calf) in group 3. Photography of the preoperative and postoperative 6 month state revealed higher satisfaction in Group 2, 3 compared to Group 1. Use of botulinum toxin type A in calf reduction is a very simple, safe, non-invasive method and effective in terms of calf contouring rather than reduction of calf circumference.