• 한국어병학회지
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• 제25권3호
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• pp.165-172
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• 2012

Vibrio alginolyticus (V. alginolyticus) 는 우리나라 전 연안에서 높은 빈도로 발견되며 인간 및 어패류에 감염을 유발시키는 박테리아의 일종이다. 본 연구는 서해안 양식장의 해수와 어패류에서 V. alginolyticus와 이에 대한 특이적인 용균성 파아지를 분리하였으며 분리된 파아지의 형태학적 특성을 전자현미경으로 확인 하였다. 또한 파아지의 핵산의 종류 및 구조 단백질의 특성 대한 연구가 수행되었다. 분리된 파아지는 형태학적으로 60 nm의 육각형 두부와 20 nm의 짧은 미부를 가진 podoviridae과로 분류되었다. 핵산을 분리한 결과 23 Kb 크기의 DNA로 판명 되었으며 구조 단백질은 37.8 kDa과 198 kDa 사이에 7종류의 단백질 분획이 존재함을 확인 하였다.

• 한국식품영양학회지
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• 제27권1호
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• pp.10-21
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• 2014

This study is conducted to investigate the effects of Chinese artichoke powder on the antioxidant activities and the quality characteristics of tofu. Tofus are being prepared with different amounts of Chinese artichoke powder in ratios of 0, 0.2, 0.4, 0.6 and 0.8% according to the soy milk quantity. According to the increasing contents of Chinese artichoke powder, the yield and turbidity of tofus are significantly increased (p<0.001) whereas the pH levels of tofus are significantly decreased (p<0.001). In terms of color, the L, a and b values are significantly decreased with increasing Chinese artichoke powder concentrations (p<0.001). From the texture profile analysis of the tofus, the chewiness, gumminess and cohesiveness of tofus are significantly decreased (p>0.01) according to the levels of added Chinese artichoke powder content. The contents of isoflavones such as daidzin and genistin are significantly increased with increasing concentrations of Chinese artichoke powder (p<0.001). The microstructure of tofus is being examined by SEM (Scanning Electron Microscope). In the sensory test, the sample which contains 0.4% of Chinese artichoke powder is ranked significantly higher (p>0.001) than the other groups according to several sensory parameters such as appearance, color, flavor, taste, texture and the overall preferences.

• 한국식품영양과학회지
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• 제29권5호
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• pp.770-776
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• 2000

Pasting gelatinization of acorn flours which were prepared with soaked nut and sediment at 7.8$^{\circ}C$ for 0, 1, 2, 3 and 4 days were investigated. The peak temperature of gelatinization of untreated acorn flour (0-0) by Rapid Visco Analyzer was 73.1$^{\circ}C$, respectively, but those of flours were decreased by soaking. Peak viscosity, setback and breakdown of acorn flours were increased by soaking. In addition, consistency was increased by soaking treatment. From the result of the pasting properties, gel formation ability of acorn flour was increased with increasing soaking days of acorn nut and soaking times of sediment. The gelatinization temperature examined by X-ray diffractometry was lowered with increasing of soaking days. The observation of microstructure through a scanning electron microscope revealed that gelatinized acorn flour showed loser their original shape and structure than that of with out soaking treatment (0-0). The degree of gelatinization under the fixed temperature increased with increasing soaking days. From these results, it might be concluded that the increase of soaking days and soaking times is the factor affecting the gelatinization of acorn flour.

• 한국식품영양과학회지
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• 제29권5호
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• pp.766-769
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• 2000

수침과정을 달리하여 제조한 도토리 앙금의 입자 특성을 조사하였다. 도토리 앙금의 X-선 회절도는 회절각도 $(2{\theta})14.5^{\circ},\;17.2^{\circ},\;19.7^{\circ},\;22.2^{\circ},\;24.5^{\circ}$에서 피크를 보이는 B형의 결정형을 보였으며, 열매의 수침과 앙금의 수침에는 영향을 받지 않았다. 또한 도토리 앙금 중 전분 입자는 대부분 타원형이며 일부는 모서리가 둥근 삼각형 모양이 존재하였고 중앙에는 hilum이 있었으며, 크기는 대부분 $10~20\;\mu\textrm{m}$ 범위였다. 열매의 앙금의 수침 과정 중 전분 입자에 붙어 있었던 비전분 성분은 대부분 제거되었다. 이상의 결과로 보아 도토리 열매와 앙금을 수침하는 기간이 입자의 성상이나 결정도에 큰 영향을 주지 않는 것으로 판단된다.

• Advances in concrete construction
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• 제8권3호
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• pp.239-246
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• 2019

Substitution of natural fine aggregates with industrial by-products like precious slag balls (PS Balls) offers various advantages like technical, economic and environmental which are very important in the present era of sustainability in construction industry. PS balls are manufactured by subjecting steel slag to slag atomizing Technology (SAT) which imparts them the desirable characteristics of fine aggregates. The main objective of this research paper is to assess the feasibility of producing good quality concrete by using PS balls, to identify the potential benefits by their incorporation and to provide solution for increasing their utilization in concrete applications. The study investigates the effect of PS balls as partial replacement of fine aggregates in various percentages (20%, 40%, 60%, 80% and 100%) on mechanical properties of concrete such as compressive strength, splitting tensile strength, and flexural strength. The optimum mix was found to be at 40% replacement of PS balls with maximum strength of 62.89 MPa at 28 days curing. Permeability of concrete was performed and it resulted in a more durable concrete with replacement of PS balls at 40% and 100% as fine aggregates. These two specific values were considered as optimum replacement is 40% and also the maximum possible replacement is 100%. Scanning electron microscope (SEM) analysis was done and it was found that the PS balls in concrete were unaffected and with optimum percentage of PS balls as fine aggregates in concrete resulted in good strength and less cracks. Hence, it is possible to produce good workable concrete with low water to cement ratio and higher strength concrete by incorporating PS balls.

• 통합자연과학논문집
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• 제14권1호
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• pp.1-5
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• 2021

라디오 진동수 스퍼터를 이용하여 실리콘(110) 기판위에 증착시간을 60분, 120분 그리고 180을 변화시켜서 산화아연 박막을 만들었다. ZnO₂ 박막의 입자 성장면을 X선 회절 장치를 써서 분석한 결과 박막의 주 성장면(002)면과 (103)면의 방향이 증착 시간의 영향을 많이 받았다. 전자 주사 현미경을 통하여 ZnO₂박막의 입자 성장을 관찰 한 결과 ZnO₂박막이 증착 초기에는 성장이 정체되는 인큐베이션 시간이 필요하다가 일정 시간이 지나면 다시 입자 성장이 일어나는 현상이 관찰 되었다. ZnO₂박막의 화학 분석을 한 결과는 증착 시간의 증가가 ZnO₂박막내의 산소의 양과는 변화가 없었지만 Zn의 성분에 변화가 관찰 되어서 박막의 증착 시간이 박막내의 Zn성분에는 영향을 미침을 알 수 있었다.

• The Journal of Advanced Prosthodontics
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• 제11권1호
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• pp.41-47
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• 2019

PURPOSE. Surface finishing of a zirconia restoration is essential after clinical adjustment. Herein, we investigated the effects of a surface finishing protocol for monolithic zirconia on final roughness and bacterial adherence. MATERIALS AND METHODS. Forty-eight disk-shaped monolithic zirconia specimens were fabricated and divided into four groups (n = 12) based on initial surface treatment, finishing, and polishing protocols: diamond bur+polishing bur (DP group), diamond bur+stone grinding bur+polishing bur (DSP group), no diamond bur+polishing bur (NP group), and no diamond bur+stone grinding bur+polishing bur (NSP group). Initial and final surface roughness was measured with a profilometer, and shown using scanning electron microscope. Bacterial adhesion was evaluated by quantifying Streptococcus mutans in the biofilm. Kruskal-Wallis and Mann-Whitney U tests were used to compare results among groups, and two-way analysis of variance was used to evaluate the effects of grinding burs on final roughness (${\alpha}=.05$). RESULTS. The DP group had the highest final Ra value, followed by the DSP, NP, and NSP groups. Use of the stone grinding bur as a coarse-finishing step significantly decreased final Ra values when a diamond bur was used (P<.001). Omission of the stone grinding bur increased biofilm formation on specimen surfaces. Combining a stone grinding bur with silicone polishing burs produced the smallest final biofilm values, regardless of the use of a diamond bur in initial surface treatment. CONCLUSION. Coarse finishing of monolithic zirconia with a stone grinding bur significantly decreased final Ra values and bacterial biofilm formation when surfaces had been roughened by a diamond bur.

• Membrane and Water Treatment
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• 제10권2호
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• pp.165-178
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• 2019

Mixed matrix membranes (MMMs) of poly (vinyl alcohol) (PVA) containing certain amounts of H-${\beta}$ zeolite for pervaporation were manufactured by using a solution casting protocol. These zeolite-embedded membranes were then characterized with scanning electron microscope (SEM), X-ray diffraction (XRD) and swelling tests. The membrane separation performance has been examined by means of isopropanol (IPA) dewatering from its highly concentrated aqueous solutions via response surface methodology (RSM). The results have demonstrated that the influences of feed IPA composition (85-95 wt.%), feed temperature ($50-70^{\circ}C$), zeolite loading (15-25 wt.%) and their interactive influences are all statistically significant on both pervaporation flux ($398-1228g/m^2{\cdot}h$) and water/isopropanol separation factor (617-2001). The quadratic models based on the RSM analysis have performed excellently to correlate experimental data with very high determination coefficients and very low relative standard deviations. The optimal pervaporation predictions given by using the RSM models demonstrate a total flux of $953g/m^2{\cdot}h$ and separation factor of 1458, and are excellently verified by experimental results. As reflected by these results, PVA MMMs embedded with hydrophilic $H-{\beta}$ zeolite entities have performed considerably better than its pure counterpart and indicated great potential for isopropanol dehydration applications.

• The Journal of Advanced Prosthodontics
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• 제11권4호
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• pp.223-231
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• 2019

PURPOSE. The purpose of this study was to evaluate the shear bond strength (SBS) of an indirect resin composite (IRC) to the various resin matrix ceramic (RMC) blocks using different surface treatments. MATERIALS AND METHODS. Ninety-nine cubic RMC specimens consisting of a resin nanoceramic (RNC), a polymer-infiltrated hybrid ceramic (PIHC), and a flexible hybrid ceramic (FHC) were divided randomly into three surface treatment subgroups (n = 11). In the experimental groups, untreated (Cnt), tribochemical silica coating (Tbc), and Neodymium-Doped Yttrium Aluminum Garnet (Nd:YAG) laser irradiation (Lsr) with 3 W (150 mJ/pulse, 20 Hz for 20 sec.) were used as surface treatments. An indirect composite resin (IRC) was layered with a disc-shape mold ($2{\times}3mm$) onto the treated-ceramic surfaces and the specimens submitted to thermal cycling (6000 cycles, $5-55^{\circ}C$). The SBS test of specimens was performed using a universal testing machine and the specimens were examined with a scanning electron microscope to determine the failure mode. Data were statistically analyzed with two-way analysis of variance (ANOVA) and Tukey HSD test (${\alpha}=.05$). RESULTS. According to the two-way ANOVA, only the surface treatment parameter was statistically significant (P<.05) on the SBS of IRC to RMC. The SBS values of Lsr-applied RMC groups were significantly higher than Cnt groups for each RMC material, (P<.05). Significant differences were also determined between Tbc surface treatment applied and untreated (Cnt) PIHC materials (P=.039). CONCLUSION. For promoting a reliable bond strength during characterization of RMC with IRC, Nd:YAG laser or Tbc surface treatment technique should be used, putting in consideration the microstructure and composition of RMC materials and appropriate parameters for each material.

• 한국환경과학회지
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• 제28권6호
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• pp.561-570
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• 2019

A zeolitic material (Z-Y2) was synthesized from Coal Fly Ash (CFA) using a fusion/hydrothermal method under low-alkali condition (NaOH/CFA = 0.6). The adsorption performance of the prepared zeolite was evaluated by monitoring its removal efficiencies for Sr and Cs ions, which are well-known as significant radionuclides in liquid radioactive waste. The XRD (X-ray diffraction) patterns of the synthesized Z-Y2 indicated that a Na-A type zeolite was formed from raw coal fly ash. The SEM (scanning electron microscope) images also showed that a cubic crystal structure of size $1{\sim}3{\mu}m$ was formed on its surface. In the adsorption kinetic analysis, the adsorption of Sr and Cs ions on Z-Y2 fitted the pseudo-second-order kinetic model well, instead of the pseudo-first-order kinetic model. The second-order kinetic rate constant ($k_2$) was determined to be $0.0614g/mmol{\cdot}min$ for Sr and $1.8172g/mmol{\cdot}min$ for Cs. The adsorption equilibria of Sr and Cs ions on Z-Y2 were fitted successfully by Langmuir model. The maximum adsorption capacity ($q_m$) of Sr and Cs was calculated as 1.6846 mmol/g and 1.2055 mmol/g, respectively. The maximum desorption capacity ($q_{dm}$) of the Na ions estimated via the Langmuir desorption model was 2.4196 mmol/g for Sr and 2.1870 mmol/g for Cs. The molar ratio of the desorption/adsorption capacity ($q_{dm}/q_m$) was determined to be 1.44 for Na/Sr and 1.81 for Na/Cs, indicating that the amounts of desorbed Na ions and adsorbed Sr and Cs ions did not yield an equimolar ratio when using Z-Y2.