• Journal of Microbiology and Biotechnology
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• v.15 no.4
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• pp.701-709
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• 2005

An efficient method of selecting an antagonistic strain for use as a biological control agent strain was developed. In this improved method, the surface tension reduction potential of an isolate was included in the 'decision factor,' in addition to two other factors; the growth rate and pathogen inhibition. By using a statistically designed method, an isolate from the soil was selected and identified as Bacillus sp. GB 16. In the pot test, this strain showed the best performance among the isolated strains. The lowest disease incidence rate and fastest seed growth were observed when the Bacillus sp. GB 16 was used. The action of the surface tension reducing component was assumed to enhance the wetting, spreading, and residing of the antagonistic strain in the rhizosphere. This result showed that the improved selection method was quite effective in selecting the best antagonistic strain for the biological control of soilborne infectious plant pathogens.

• Journal of the Korean Applied Science and Technology
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• v.3 no.1
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• pp.65-71
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• 1986

Four amphoteric surfactants, 1-(N-alkyl-N,N-dimethyl ammonio)-4-naphthalene sulfonates, were prepared by the alkylation of 1-(N,N-dimethylamino)-4,naphthalene sulfonic acid with chloroalkanes such as 1-decylchloride, 1-tetradecyl chloride and 1-hexadecyl chloride. These quaternary ammonium compounds such as 1-(N-decyl-N, N-dimethylammonio)-4-naphthalene sulfonate, 1-(N-dodecyl-N,N-dimethylammonio)-4-naphthalene sulfonate, 1-(N-tetradecyl-N,N-dimethylammonio)-4-naphthalene sulfonate and 1-(N-hexadecyl-N,N-dimethylammonio)-4-naphthalene sulfonate could be separated by means of thin layes chromatography and column chromatography. The surface chemical properties such as surface tension, foaming power, foam stability, wetting efficiency and solubilizing effect for these four compounds were measured. Also critical micelle concentration and hydrophilic-lipophilic balance(HLB) were evaluated. These compounds showed good surface as O/W type emulsifying agent and detergent.

• Fibers and Polymers
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• v.7 no.3
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• pp.286-294
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• 2006

This study has examined the flexural properties of natural and chemically modified coir fiber reinforced cementitious composites (CFRCC). Coir fibers of two different average lengths were used, and the longer coir fibers were also treated with a 1% NaOH solution for comparison. The fibers were combined with cementitious materials and chemical agents (dispersant, defoamer or wetting agent) to form CFRCC. The flexural properties of the composites, including elastic stress, flexural strength, toughness and toughness index, were measured. The effects of fiber treatments, addition of chemical agents and accelerated ageing of composites on the composites' flexural properties were examined. The results showed that the CFRCC samples were 5-12 % lighter than the conventional mortar, and that the addition of coir fibers improved the flexural strength of the CFRCC materials. Toughness and toughness index, which were associated with the work of fracture, were increased more than ten times. For the alkalized long coir fiber composites, a higher immediate and long-term toughness index was achieved. SEM microstructure images revealed improved physicochemical bonding in the treated CFRCC.

• ETRI Journal
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• v.32 no.3
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• pp.414-421
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• 2010

The interconnection mechanisms of a smart anisotropic conductive adhesive (ACA) during processing have been characterized. For an understanding of chemorheological mechanisms between the fluxing polymer and solder powder, a thermal analysis as well as solder wetting and coalescence experiments were conducted. The compatibility between the viscosity of the fluxing polymer and melting temperature of solder was characterized to optimize the processing cycle. A fluxing agent was also used to remove the oxide layer performed on the surface of the solder. Based on these chemorheological phenomena of the fluxing polymer and solder, an optimum polymer system and its processing cycle were designed for high performance and reliability in an electrical interconnection system. In the present research, a bonding mechanism of the smart ACA with a polymer spacer ball to control the gap between both substrates is newly proposed and investigated. The solder powder was used as a conductive material instead of polymer-based spherical conductive particles in a conventional anisotropic conductive film.

• Korean Journal of Metals and Materials
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• v.50 no.5
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• pp.353-360
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• 2012

The corrosion product of archaeological iron objects is supposed to be removed because it causes re-corrosion. So far it is removed by scapel and sand blaster but they depend on the skill and experience of a conservator and the glass-dust of the sand blaster is harmful to humans. Therefore this study applies a laser cleaning system which is used in various industrial cleaning processes, to remove corrosion product from archaeological iron objects. In addition, this work studies the alternation of corrosion product after laser irradiation, which evaluates the reliability of the laser cleaning system. Optical microscopy, SEM-EDS, XRD, Raman have been used to observe and analyse the surface of the objects. The results show the capacity of laser cleaning some corrosion product, but blackening appears with increasing pulses and laser energy, and some corrosion products, goethite and hematite, are partially altered to magnetite. These problems, blackening and alternation of corrosion product, should be solved by further studies which find the optimal laser irradiation condition and use a wetting agent.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.40-44
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• 2003

Soil-borne infectious disease including Pythium aphanidermatum and Rhizoctonia solani causes severe damage to plants, such as cucumber. This soil-borne infectious disease was not controlled effectively by chemical pesticide. Since these diseases spread through the soil, chemical agents are usually ineffective. Instead, biological control, including antagonistic microbe can be used as a preferred control method. An efficient method was developed to select an antagonistic strain to be used as a biological control agent strain. In this new method, surface tension reduction potential of an isolate was included in the ‘decision factor’ in addition to the other factors, such as growth rate, and pathogen inhibition rate. Considering these 3 decision factors by a statistical method, an isolate from soil was selected and was identified as Bacillus sp. GB16. In the pot test, this strain showed the best performance among the isolated strains. The lowest disease incidence rate and fastest seed growth was observed when Bacillus sp. GB16 was used. Therefore this strain was considered as plant growth promoting rhizobacteria (PGPR). The action of surface tension reducing component was deduced as the enhancement of wetting, spreading, and residing of antagonistic strain in the rhizosphere. This result showed that new selection method was significantly effective in selecting the best antagonistic strain for biological control of soil-borne infectious plant pathogen. The antifungal substances against P. aphanidermatum and R. solani were partially purified from the culture filtrates of Bacillus sp. GB16. In this study, lipopeptide possessing antifungal activity was isolated from Bacillus sp. GB16 cultures by various purification procedures and was identified as a surfactin-like lipopeptide based on the Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), high performance liquid chromatography mass spectroscopy (HPLC-MS), and quadrupole time-of-flight (Q-TOF) ESI-MS/MS data. The lipopeptide, named GB16-BS, completely inhibited the growth of Pythium aphanidermatum, Rhizoctonia solani, Penicillium sp., and Botrytis cineria at concentrations of 10 and 50 mg/L, respectively. A novel method to prevent the foaming and to provide oxygen was developed. During the production of surface active agent, such as lipopeptide (surfactin), large amount of foam was produced by aeration. This resulted in the carryover of cells to the outside of the fermentor, which leads to the significant loss of cells. Instead of using cell-toxic antifoaming agents, low amount of hydrogen peroxide was added. Catalase produced by cells converted hydrogen peroxide into oxygen and water. Also addition of corn oil as an oxygen vector as well as antifoaming agent was attempted. In addition, Ca-stearate, a metal soap, was added to enhance the antifoam activity of com oil. These methods could prevent the foaming significantly and maintained high dissolved oxygen in spite of lower aeration and agitation. Using these methods, high cell density, could be achieved with increased lipopeptide productivity. In conclusion to produce an effective biological control agent for soil-borne infectious disease, following strategies were attempted i) effective screening of antagonist by including surface tension as an important decision factor ii) identification of antifungal compound produced from the isolated strain iii) novel oxygenation by $H_2O_2-catalase$ with vegetable oil for antifungal lipopeptide production.

• Restorative Dentistry and Endodontics
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• v.20 no.2
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• pp.699-720
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• 1995

This study was conducted to evaluate the effect of benzalkonium chloride solution as a wetting agent instead of water on dentin bonding with NTG-GMA/BPDM system (All-bond 2, Bisco.) and DSDM system (Aelitebond, Bisco.). Benzalkonium chloride solution is a chemical disinfectant widely used in medical and dental clinics for preoperative preparation of skin and mucosa due to its strong effect of cationic surface active detergent. Eighty freshly extracted bovine lower incisor were grinded labially to expose flat dentin surface, and then were acid-etched with 10 % phosphoric acid for 15 second, water-rinsed, and dried for 10 second with air syringe. The specimens were randomly divided into 8 groups of 10 teeth. The specimens of control group were remoistured with water and the specimens of experimental groups were remoistured with 0.1 %, 0.5 %, and 1.0 % benzalkonium chloride solution respectively. And then, the Aelitefil composite resin was bonded to the pretreated surface of the specimens by use of All-bond 2 dentin bonding system or Aelitebond dentin bonding system in equal number of the specimens. The bonded specimens were stored in $37^{\circ}C$ distilled water for 24 hours, then the tensile bond strength was measured, the mode of failure was observed, the fractured dentin surface were examined under scanning electron microscopy, and FT-IR spectroscopy was taken for the purpose of investigating the changes of the dentin surface pretreated with benzal konium chloride solution followed by each primer of the dentin bonding systems. The results were as follows : In the group of bonding with NTG-GMA/BPDM dentin bonding agent(All-bond 2), higher tensile bond strength was only seen in the experimental group remoistured with 0.1 % benzal konium chloride solution than that in water-remoistured control group(p<0.05). In the group of bonding with DSDM dentin bonding agent (Aelitebond), no significant differences were seen between the control and each one of the experimental group(p<0.05). Higher tensile bond strength were seen in NTG-GMAIBPDM dentin bonding agent group than in DSDM dentin bonding agent group regardless of remoistur ization with benzal konium chloride solution. On the examination of failure mode, cohesive and mixed failure were predominantly seen in the group of bonding with NTG-GMAIBPDM dentin bonding agent, while adhesive failure was predominantly seen in the group of bonding with DSDM dentin bonding agent. On SEM examination of fractured surfaces, no differences of findings of primed dentin surface between the groups with and without remoisturization with benzal konium chloride solution. FT-IR spectroscopy taken from the control and the experimental group reve::.led that some higher absorbance derived from the primers binding to dentin surface was seen at the group pretreated with 0.1 % benzal konium chloride solution than at the control group of remoisturizing with water.

• Horticultural Science & Technology
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• v.18 no.5
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• pp.612-620
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• 2000

In developing soil wetting agent using polyoxyethylene octylphenyl ether [$C_8H_{17}O(C_2H_4O)_{10}H$, POE], the effect of mixtures of POE and polyoxyethylene+polypropyleneoxide tridecylether (1:1, w/w, CM-1), polyoxyethylene+polypropyleneoxide tridecylether+propyleneglycol monomethylether (1:1:2, w/w/w, CM-2) or glycerin+ditridecyl phthalate (1:1, w/w, CM-3) on changes of concentration of POE, initial wetting, evaporative water loss, water infiltration, and changes of physical properties in root media were determined. The mixtures of POE and CM-1, 2, or 3 with zeolite or vermiculite as carrier had high concentrations of POE in root media during 6 elution times, but those after 6 times decreased rapidly indicating unstable elution of POE. The commercial AquaGro was more effective than the mixtures of POE+CM-1, 2, or 3 in water retention during 18 hours. Root media incorporated with POE+CM-2 held more water than any other treatments at 84 hours after watering, but the differences among treatments except control were not significant. In the treatments with zeolite as a carrier, POE+CM-3 had the greatest evaporative water loss followed by POE+CM-2, AquaGro, control, and POE+CM-2. In the treatments with vermiculite as a carrier, POE+CM-1 had the highest evaporative water loss followed by POE+CM-3, AquaGro, control, and POE+CM-2. In the effect of mixtures with zeolite as a carrier on infiltration of water into root media, the treatment of POE+CM-1 had the highest amount of water infiltrated followed by POE+CM-3, AquaGro, POE+CM-2, and control. In the effect of mixtures with vermiculite as a carrier on infiltration of water into root media, the treatment of POE+CM-3 had the highest amount of water infiltrated followed by AquaGro, POE+CM-1, POE+CM-2, and control.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.2
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• pp.412-417
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• 2009

In order to investigate the effective sericin fixation of raw silk fibers the influence of various additives added to the melamine and formalin mixtures on sericin fixation was studied. When raw silk fibers were treated with wetting agent but without subsequent washing before sericin fixation, the strong sericin fixation was obtained by fixing sericin. Adding hydrogen peroxide to the melamine and formalin mixture made sericin fixation worse, resulting weaken the sericin hardness of fixed raw silk fibers and tight bonding of the fibers. On the other hand, it was confirmed that adding sodium hydrosulfite to the melamine and formalin mixtures gave better sericin hardness of fixed raw silk fibers without the bonding of fibers. Supplying additional melamine with he low concentration of sodium hydroxide to the melamine and formalin mixture(melamine:formalin= 1:6) resulted in very good sericin fixation. But adding hydrochloric acid or methanol to the same mixture had no effect on the sericin fixation, and adding magnesium chloride to it made the hardness of sericin fixation even worse.

• Clean Technology
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• v.15 no.3
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• pp.180-185
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• 2009

The ethylene-propylene rubber (EPDM) scrap generated from automobile weatherstrip manufacturing process was used to make a thermoplastic elastomer through blending with polypropylene. The surface activated EPDM powder was obtained by the high temperature and shear pulverizer. The addition of surfactant resulted in more surface activated EPDM powder and the optimum loading amounts of surfactant was 1.5 phr. Maleic anhydride was grafted onto polypropylene by reactive blending to give functionalized polypropylene. The wetting property between EPDM scrap and polypropylene was improved by the addition of poly (ethylene-co-acrylic acid) as a compatibilizing agent. Poly(ethylene-co-acrylic acid) decreased the surface tension of polypropylene and thus would contribute to the wettability with EPDM powder.