• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.3
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• pp.89-95
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• 2022

In this study, glassy carbon coating was performed on the graphite using a phenolic resin and a curing agent was mixed with ethylene glycol as an additive to form the uniform surface. The phenolic resin was dried and cured under the environments of hot air, then converted into a glassy carbon layer by pyrolysis at 500~1,500℃. FTIR, XRD, SEM analysis, and density/porosity/contact angle measurement were performed for characterization of glassy carbon. The pyrolysis temperature for high-quality glassy carbon was optimized to be about 1,000℃. As the content of the additive increased, the effect of reducing surface defects on the coated surface, reduction of porosity, increase of contact angle, and increase of density were investigated in this study. The method of forming a glassy carbon coating layer through an additive is expected to be applicable to graphite coating and other fields.

• Journal of Korean Society of Forest Science
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• v.77 no.3
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• pp.294-302
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• 1988

The experiment was carried out to investigate the properties of bark extractives form Larix epilepsies and to evacuate their suitability as a bonding agent. The yield and reactivity were measured to examine the influence of temperature and time and the effect of carbonation and sulfonation. To define the possibility of practical application as wood adhesives the viscosity and gelation time were measured at 33% concentration. The results obtained were summarized as follows : 1. As the both yield and reactivity were high, extraction for 2 hours at $80^{\circ}C$ was the optimal temperature and time. 2. The highest effect achieved at 1% $Na_2CO_3$ about carbonation and 1% $Na_2SO_3$ : $NaHSO_3$ and 0.25% $Na_2SO_3$ about sulfonation. The sulfonation of 0.25% $Na_2SO_3$ increased the yield and reactivity most highly. 3. By using hot water as extraction liquid the yield was 17.2%, while the addition of 1% and 5% NaOH to the extraction liquid increased the yield to 38.6% and 44.6%, respectively. 4. Hot water extracts showed the highest reactivity(68.8%). The addition of 1% and 5% NaOH led to decrease in reactivity(49.3% and 25.8%, respectively). 5. At 33% concentration of the extracts the viscosity appeared very variable. Significantly high values of viscosity was measured in 1% NaOH solution, while very low values appeared for 5% NaOH solution. 6. The shortest gelation time was determined at pH 7 to 10 and the highest at pH 4. The use of paraformaldehyde resulted in gelation times longer than those of 37% formaldehyde solution. 7. Except the sulfonation extracts of hot water and 1% NaOH, the other extracts were found unsuitable due to high viscosity(1% NaOH extracts, sulfonation extracts) or to curing inability(5% NaOH extracts, sulfonation extracts of 5% NaOH). 8. From the three extract solutions which appeared to be suitable for use as bonding agents the hot water extracts and the sulfonation extracts of hot water were superior in extract reactivity, while the sulfonation extracts of 1% NaOH exceeded the other two extracts in extract yield.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.1
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• pp.25-39
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• 2022

This study was conducted to evaluate the manufacturing process of non-sintered cement for the safe containment of radioactive waste using low level or ultra-low level radioactive waste soil generated from nuclear-decommissioning facilities, clay minerals, and blast furnace slag (BFS) as an industrial by-product recycling and to characterize the products using mineralogical and morphological analyses. A stepwise approach was used: (1) measuring properties of source materials (reactants), such as waste soil, clay minerals, and BFS, (2) manufacturing the non-sintered cement for the containment of radioactive waste using source materials and deducing the optimal mixing ratio of solidifying and adjusting agents, and (3) conducting mineralogical and morphological analyses of products from the hydration reactions of manufactured non-sintered cement solidifier (NSCS) containing waste concrete generated from nuclear-decommissioning facilities. The analytical results of NSCS using waste soil and clay minerals confirmed none of the hydration products, but calcium silicate (CSH) and ettringite were examined as hydration products in the case of using BFS. The compressive strength of NSCS manufactured with the optimum mixing ratio and using waste soil and clay minerals was 3 MPa after the 28-day curing period, and it was not satisfied with the acceptance criteria (3.44 MPa) for being brought in disposal sites. However, the compressive strength of NSCS using BFS was estimated to be satisfied with the acceptance criteria, despite manufacturing conditions, and it was maximized to 27 MPa at the optimal mixing ratio. The results indicate that the most relevant NSCS for the safe containment of radioactive waste can be manufactured using BFS as solidifying agent and using waste soil and clay minerals as adsorbents for radioactive nuclides.

• Food Science of Animal Resources
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• v.31 no.3
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• pp.469-476
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• 2011

This study was conducted to evaluate the functional effects of adding oyster shell powder on the quality properties and storage stability of emulsion-type pork sausages to substitute phosphates as a curing agent. Seven treatments were prepared: T1 (Control), T2 (0.3% STPP), T3 (1.5% NaCl), T4 (1.5% NaCl + 0.5% whey protein), T5 (1.5% NaCl + 0.5% whey protein + 0.15% oyster shell powder), T6 (1.5% NaCl + 0.5% whey protein + 0.3% oyster shell powder), and T7 (1.5% NaCl + 0.5% whey protein + 0.5% oyster shell powder). Significant differences were observed for ash in the proximal analysis. Adding 0.5% oyster shell powder significantly increased pH values when compared to the other treatments. Pork sausages with 0.3% oyster shell powder had significantly improved water holding capacity and cooking loss. Adding oyster shell powder (0.15, 0.3, and 0.5%) resulted in significantly higher hardness, cohesiveness, springiness, and chewiness values than those in the other treatments. No significant differences were observed among treatments during 14 d of cold storage at $4^{\circ}C$.

• Restorative Dentistry and Endodontics
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• v.35 no.3
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• pp.164-172
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• 2010

During a composite resin restoration, an anticipating contraction gap is usually tried to seal with low-viscosity resin after successive polishing, etching, rinsing and drying steps, which as a whole is called rebonding procedure. However, the gap might already have been filled with water or debris before applying the sealing resin. We hypothesized that microleakage would decrease if the rebonding agent was applied before the polishing step, i.e., immediately after curing composite resin. On the buccal and lingual surfaces of 35 extracted human molar teeth, class V cavities were prepared with the occlusal margin in enamel and the gingival margin in dentin. They were restored with a hybrid composite resin Z250 (3M ESPE, USA) using an adhesive AdperTM Single Bond 2 (3M ESPE). As rebonding agents, BisCover LV (Bisco, USA), ScotchBond Multi-Purpose adhesive (3M ESPE) and an experimental adhesive were applied on the restoration margins before polishing step or after successive polishing and etching steps. The infiltration depth of 2% methylene blue into the margin was measured using an optical stereomicroscope. The correlation between viscosity of rebonding agents and mciroleakage was also evaluated. There were no statistically significant differences in the microleakage within the rebonding procedures, within the rebonding agents, and within the margins. However, when the restorations were not rebonded, the microleakage at gingival margin was significantly higher than those groups rebonded with 3 agents (p < 0.05). The difference was not observed at the occlusal margin. No significant correlation was found between viscosity of rebonding agents and microleakage, except very weak correlation in case of rebonding after polishing and etching at gingival margin.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.2
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• pp.153-159
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• 2012

The objective of this study was to assess the effect of salivary contamination on shear bond strength of pit and fissure sealant using several bonding agents by means of applying saliva at different stages of treatment. 56 teeth were randomly divided into one of seven groups (8 per group): (Group A, B) acid etching; (Group C, D, E) Adper$^{TM}$ Single Bond after acid-etching; (Group F, G) Adper$^{TM}$ Prompt L-pop. Saliva was applied to teeth surface of B, D, E, and G groups for 10 seconds. Especially, group D was contaminated after acid-etching and group E was contaminated with saliva after adhesive application. After light curing, all of the specimens were thermocycled and the shear bond strength tests were performed. The results were as follows. 1. In generally performed pit and fissure sealant group, shear bonding strength significantly differently reduced when was contaminated by saliva (p<0.05). However the group that was applied with bonding agent during pit and fissure sealant procedure, there were no significant differences in the kind of bonding agents nor the stage of contamination. 2. In group that was not contaminated by saliva during pit and fissure sealant treatment, Adper$^{TM}$ Single Bond yielded the highest bonding strength but there were no significant differences. 3. The failure pattern on the debonded surfaces shows that most specimens from groups using bonding agents showed cohesive failures while most specimens from groups that didn't use bonding agents showed adhesive failures.

• Journal of the Daesoon Academy of Sciences
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• v.38
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• pp.1-46
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• 2021

Since ancient times, the word Deok (德, virtue) has been used as a term in ethics. In the east, it originally meant 'to acquire (得),' and during the warring states period, it was used to indicate 'personality' or 'value;' especially for political leaders. Then, in Confucianism, the word Deok developed into an ethical term suggesting that people should acquire Deok in their action so as to achieve human perfection. In Daesoon Thought, Deok originates from the Dao, and the two are close in the same manner that Yin and Yang are close and interrelated. The Dao of Daesoon Thought indicates the Great Dao of Heaven and Earth, which Gucheon Sangje had opened when he performed his Gongbu (holy work) at Daewonsa Temple, is such that the Great Deok was divided into the Deok of Heaven, the Deok of Earth, and the Deok of Humanity. This allows for the realization of Deok in each of the Three Realms. Jo Jeongsan, the successor of Gucheon Sangje, said that he will inherit the Great Deok originated from the Great Dao and enlighten the world to the Dao. The cause of the accumulation of grievances in the Three Realms was due to the failure to sufficiently spread Deok throughout the Three Realms. The Later World is where Deok will be offered in its full extent as it was secured by the Cheonjigongsa (Reordering Works of Heaven and Earth) performed by Gucheon Sangje. However, as the main agent of spreading Deok is the heart-mind, humans need to cultivate their heart-mind in the correct way. When humans finally become Dotong-gunja (beings who are perfectly unified with the Dao) and generously practice Deok in the world, there will be no grievances anywhere in the Three Realms. There are four ways of practicing Deok: Deok by caring for life, Eondeok (Deok of speech), Gongdeok (practicing meritorious Deok), and Podeok (spreading of Deok) to the world. Practicing the Deok by caring for life is to save and protect living beings based on the spirit of Jesaenguise (saving lives and curing the world). Eondeok is practiced when people speak to others in a positive way that fosters widespread goodness based on the spirit of Sangsaeng (mutual beneficence). When people perform Gongdeok they will be rewarded for their actions. Podeok can be realized when the followers of Sangje spread the Great Dao of Heaven and Earth based on the teachings of Daesoon Thought.