• Korean Journal of Materials Research
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• v.14 no.10
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• pp.725-730
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• 2004

Nickel ultrafine powder have been synthesized by chemical reduction of aqueous $NiSO_4$ with hydrazine at various reaction conditions. The effect of reaction conditions such as the amount of surfactant and reductor, and reaction temperature on the particle size and shape was investigated by the mean of XRD, SEM and SEM-PSA. Experiments showed that the ratio of $N_{2}H_4/Ni$ and the reaction temperature were affected on the particle size of the nickel powder. The average particle size of synthesized nickel powder increased with increasing reaction temperature regardless of the ratio of $N_{2}H_4/Ni$. Also the surfactant could influence the size and agglomeration of ultrafine powder with the reaction temperature.

• Journal of Powder Materials
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• v.24 no.2
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• pp.141-146
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• 2017

$Bi_2Te_3$ powders are recovered by wet chemical reduction for waste n-type thermoelectric chips, and the recovered particles with different morphologies are prepared using various surfactants such as cetyltrimethylammonium bromide (CTAB), sodium dodecylbenzenesulfonate (SDBS), and ethylenediaminetetraacetic acid (EDTA). When citric acid is added as the surfactant, the shape of the aggregated particles shows no distinctive features. On the other hand, rod-shaped particles are formed in the sample with CTAB, and sheet-like particles are synthesized with the addition of SDBS. Further, particles with a tripod shape are observed when EDTA is added as the surfactant. The growth mechanism of the particle shapes depending on the surfactant is investigated, with a focus on the nucleation and growth phenomena. These results help to elucidate the intrinsic formation mechanism of the rod, plate, and tripod structures of the $Bi_2Te_3$ recovered by the wet reduction process.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.464-465
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• 2006

Monodispersed and nano-sized Cu powders were synthesized from copper sulfate pentahydrate $(CuSO_4{\cdot}5H_2O)$ inside a nonionic polymer matrix by using wet chemical reduction process. The sucrose was used as a nonionic polymer network source. The influences of a nonionic polymer matrix on the particle size of the prepared Cu powders were characterized by means of X-ray diffraction), scanning electron microscopy), and particle size analysis). The smallen Cu powders with size of approximately 100 nm was obtained with adding of 0.04M sucrose at reaction temperature of $60\;^{\circ}C$. The particle size of the Cu powders prepared by the reduction inside polymer network was strongly dependent of the sucrose content and reaction temperature.

• Food Science and Biotechnology
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• v.14 no.4
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• pp.461-465
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• 2005

To determine the cause of wet noodle spoilage, microorganisms isolated from wet noodles were identified and characterized. In addition, the growth inhibitory effects of organic acid mixture (OA: lactic acid 27.8%, acetic acid 12.0%, succinic acid 1.0%) and sodium dehydroacetate (SD) on the isolated strain were estimated in nutrient broth medium. The isolated strain was Gram-positive, rod shaped, motile, and spore forming. Based on physiological characteristics and the API 50 CHB-kit test results for the assimilation of 49 carbohydrates, the isolated strain was identified as Bacillus amyloliquefaciens (92.6%), which is able to degrade starch. Decimal reduction times (D-values) at 100, 105, and $110^{\circ}C$ for spores of B. amyloliquefaciens were 8.5, 5.1, and 2.5 min, respectively, and the z-value was $12.8^{\circ}C$. We estimated that B. amylo-liquefaciens isolated from spoiled wet noodles was a thermophilic species having high heat-resistance. Viable cell numbers in wet noodles and broth medium inoculated with B. amyloliquefaciens were decreased by 2-4 log cycles by combined treatment with 0.03 or 0.05% OA and 0.3% SD. These results revealed that OA combined with SD could be used as a potential agent to inhibit B. amyloliquefaciens in wet noodles.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.555-557
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• 2004

We report the effect of the particle size (D50) and PSD (Particle Size Distribution) of glass frit on the transparency of transparent dielectric layer of PDP. The milling efficiency of wet milling with water was the best among the dry milling, wet milling with IPA and wet milling with water. The transparency increased with the reduction of particle size of glass frit as the milling time increased. Also the transparency changed by the PSD of glass frit. Glass frits of broad PSD showed high transparency compared with the glass frits of sharp PSD.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.177-180
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• 2012

Korea residential housing generally use wet floor heating system 'Ondol' which consist of insulation cushioning, lightweight foamed concrete, hot water pipe and mortar on top of reinforced concrete slab. Wet floor heating system's installation process is too complicate and difficult to supervise field for continuing assurance quality. Also, this method has a huge impact on the progress of construction because it take a long time to cure finishing mortar and lightweight foamed concrete. Therefore, it is considered a disturbance factor of reduction of construction duration for enhancing competitiveness. In this study, we conducted an experiment about the radiant heat performance and temperature difference on upper panel of rolled dry floor heating systems which is jointly developed by Kolon global and Sumisho Metalex for remodeling housing, studio apartment and the urban-life housing.

• Textile Coloration and Finishing
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• v.22 no.2
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• pp.123-131
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• 2010

Shape and size controlled synthesis of gold particles has been studied by using wet-chemical method. When ${AuCl_4}^-$ in aqueous $HAuCl_4$ precursor was reduced using $Na_2SO_3$ as a reducing agent, mixtures of spherical, triangular and hexagonal particles were prepared in a few minutes. It was found that the shape selective oxidative etching by ${AuCl_4}^-\;+\;Cl^-$ anions and crystal growth took place simultaneously. As the ${AuCl_4}^-$ and $Cl^-$ concentration increased, yields of large triangular and hexagonal plate type particles increased, while the spherical particles decreased in most cases. Possible etching and growth mechanisms are discussed.

• Journal of dental hygiene science
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• v.18 no.2
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• pp.76-84
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• 2018

Wet wipes are being increasingly used because of their convenience. Particularly, oral wet wipes are useful for regular cleaning of a baby's mouth after birth. Therefore, the consumption of oral wet wipes has increased over the past few years and a variety of products are commercially available. However, product information on safety is not sufficiently provided and still raises doubts regarding adverse effects. To confirm the safety of wet wipes as an oral hygiene item and provide information for their use, we investigated the cytotoxicity of oral wet wipes and verified the underlying mechanism. The anti-bacterial effect of oral wet wipes was analyzed using the disk diffusion method. The cytotoxic effects of oral wet wipes were observed based on morphological changes using microscopy and determined using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in gingival epithelial cells and gingival fibroblasts. Evaluation of apoptosis by oral wet wipes was explored using propidium iodide flow cytometric analysis and a terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP) nick-end labeling (TUNEL) assay. Apoptosis-related molecules were also analyzed using western blotting. Five types of oral wet wipes were tested, and two products from Fisher-Price and Dr. Kennedy revealed strong cytotoxic effects on gingiva epithelial cells and gingiva fibroblasts, although they also showed intense anti-bacterial effects on oral bacteria. Cell cycle arrest in the G2/M phase and apoptosis were observed based on treatment of extracts from Fisher-Price and Dr. KENNEDY. Relatively high TUNEL levels, reduction of proliferating cell nuclear antigen and cyclin-dependent kinase 4 expression, and fragmentation of poly (ADP-ribose) polymerase were also elucidated. These results suggest that commercial oral wet wipes could exert cytotoxic influences on oral tissue, although there are anti-bacterial effects, and careful attention is required, especially for infants and toddlers.

• Journal of Powder Materials
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• v.22 no.4
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• pp.260-265
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• 2015

Spherical fine cobalt powders were fabricated by new liquid reduction method. Commercial cobalt sufate heptahydrate was used as raw material. Also ethylene glycol was used as solvent and hydrazine-sodium hypophosphite mixture was used as reduction agent for the new liquid reduction method. A plate shaped cobalt powders with an approximately 300 nm were prepared by a traditional wet ruduction method using distilled water as solvent and hydrazine. Spherical fine cobalt powders with an average size of $1-3{\mu}m$ were synthesized by a new liquid reduction method in 0.3M cobalt sulfate and 1.5M hydrazine-0.6M sodium hypophosphite mixture at 333K.

• Journal of the Korea Safety Management & Science
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• v.24 no.2
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• pp.1-9
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• 2022

In korea, 500MW standard coal fired power plants were designed and operated for the initial base load, so facility stability was prioritized from facility problem to treatment, but now we needed to research for minimizing greehouse gas emissions at the operation of coal fired power plants. research on various facilities and technologies was actively conducted to reduce environment pollutants was drastically reduced, but research and attempts on coping measures in the event of a reduction facility problem were in sufficient. this study considered investigated ways to minimized pollutants by quickly responding to logic development and application of the load runback concept in case of serious problems with environmental pollutant reduction facilities such as NOx reduction selective catalytic reduction facilities, SOx reduction wet flue gas desulpherisation facilities, and TSP(Total Suspended Particles) collection low temperature electric precipitator.