• Restorative Dentistry and Endodontics
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• v.26 no.6
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• pp.492-498
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• 2001

The purpose of this study was to evaluate four different composite resins in vitro for microleakage in Class II box type restorations that have gingival margins apical to the cementoenamel junction. Forty caries free extracted human molars were used in this study. The Class II cavities were prepared 1.0mm below cementoenamel junction with a #701 carbide bur. The teeth were randomly divided into four groups, each group comprising 20 treated cavities according to adhesives and filling materials ; Group 1: Scotchbond Multipurpose/Z 100. Group 2: Ariston Liner/Ariston pHc, Group 3: One Step/Pyramid, Group 4: Prime & Bond NT/SureFil. To simulate the clinical situation during restoration placement, a restoration template was fabricated and composite resin was filled using a three sited light-curing incremental technique. The specimens were stored in the 100% humidity for 7 days prior to thermocycling. The specimens were immersed in 2% methylene blue dye solution for 24 hours and then embeded in transparent acrylic resin and sectioned mesiodistally with a diamond wheel saw. The degree of marginal leakage was scored under the stereomicroscope($\times$20) and the data were analyzed by Kruskal Wallis test and Mann Whitney test. (omitted)

• Restorative Dentistry and Endodontics
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• v.42 no.1
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• pp.60-64
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• 2017

Root canal anatomy is complex, and the recognition of anatomic variations could be a challenge for clinicians. This case report describes the importance of cone beam computed tomographyic (CBCT) imaging during endodontic treatment. A 23 year old woman was referred by her general dental practitioner with the chief complaint of spontaneous pain in her right posterior maxilla. From the clinical and radiographic findings, a diagnosis of symptomatic irreversible pulpitis was made and endodontic treatment was suggested to the patient. The patient underwent CBCT examination, and CBCT scan slices revealed seven canals: three mesiobuccal (MB1, MB2, and MB3), two distobuccal (DB1 and DB2), and two palatal (P1 and P2). Canals were successfully treated with reciprocating files and filled using single-cone filling technique. Precise knowledge of root canal morphology and its variation is important during root canal treatment. CBCT examination is an excellent tool for identifying and managing these complex root canal systems.

• Macromolecular Research
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• v.17 no.8
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• pp.568-574
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• 2009

We investigated the sintering and consolidation phenomena of silver nanoparticles under various thermal treatment conditions when they were patterned by a contact printing technique on polyimide substrate films. The sintering of metastable silver nanoparticles commenced at 180 $^{\circ}C$, where the point necks were formed at the contact points of the nanoparticles to reduce the overall surface area and the overall surface energy. As the temperature was increased up to 250 $^{\circ}C$, silver atoms diffused from the grain boundaries at the intersections and continued to deposit on the interior surface of the pores, thereby filling up the remaining space. When the consolidation temperature exceeded 270 $^{\circ}C$, the capillary force between the spherical silver particles and polyimide flat surface induced the permanent deformation of the polyimide films, leaving crater-shaped indentation marks. The bonding force between the patterned silver metal and polyimide substrate was greatly increased by the heat treatment temperature and the mechanical interlocking by the metal particle indentation.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 1997.11a
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• pp.464-471
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• 1997

Convective smoke spread in a corridor is experimentally investigated using thermocouples and visualization technique with a laser beam sheet. The speed of smoke front under a ceiling is measured by a series of thermocouples. Visualization of the ceiling jet formation and of smoke filling process is carried out to observe the lowering of a smoke layer. From the results, a large-scale convective motion plays dominant roles for smoke spread in the vicinity of the end of the corridor from visualized photos along with temperature records. The large-scale convective motion of the smoke is generated from the impingement of the ceiling jet front on the end of the corridor, and thus turning the flows toward the floor. Such a circulating motion of fluid transports some smoke to some region where its momentum is effective. It is therefore shown that the conventional concept of lowering smoke in the two-layer zone model has some restrictions for the corridor because the lowering of smoke layer has been thought to be mass transport due to relatively small scale motions such as the decrease of buoyancy, mass diffusion and momentum exchanges.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.5
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• pp.399-406
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• 2019

The variation of ground-penetrating radar(GPR) signal characteristics from dielectric-filled nonmetallic pipes buried in inhomogeneous ground are compared through a numerical simulation. The relative permittivity distribution of the ground is generated by using the continuous random media(CRM) technique. As a function of the relative permittivity of the material filling the nonmetallic pipe buried in the ground media, GPR signals are simulated by using the finite-difference time-domain(FDTD) method. We show that, unlike the case for homogeneous ground, the distortion characteristics of the reflected waves caused by the front convex surface and the rear concave surface of the pipe buried in inhomogeneous ground are different depending on the permittivity contrast between the inside and outside of the pipe.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.7
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• pp.265-273
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• 2021

The aim of this study is to analyze the correlation between concept perceptions and people's attitudes in halal tourism, development perceptions and people's attitudes, attitude and people's interest, concept perceptions and people's interest, development perceptions and people's interest, concept perceptions and people's interest, and development perceptions and people's interest. The method used in this research is SEM (Structural Equation Modeling) method. The population in this study was all Banten people. The samples in this study were respondents in five districts/cities in Banten, namely Tangerang (127 respondents), Serang (63 respondents), Pandeglang (97 respondents), Lebak (69 respondents), and Tangerang City (62 respondents). The sampling technique used is cluster random sampling. The data collection method used by researchers is a survey through filling out an online questionnaire. Based on regression test results shows concept perceptions has a significant effect on people's attitudes Development perceptions has no significant effect on people's attitudes, the attitude has no significant effect on people's interest, concept perceptions have no significant effect on people's interest, development perceptions have no significant effect on people's interest. Concept perceptions have no significant effect on people's interests through people's attitudes. Development perceptions have no significant effect on people's interests through people's attitudes.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.2
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• pp.583-593
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• 2021

The purpose of this study was to examine the relationship between transformational leadership and organizational performance with readiness to change and empower knowledge sharing quality as mediating variables. The survey was conducted by collecting the respondents' data by filling up forms which were designed using the google form application and collecting it using WhatsApp. This was performed on 400 respondents, encompassing employees from the National Agency of Drug and Food Control in Indonesia. The research model adopted was validated using Structural Equation Modeling technique with AMOS tool. The findings showed transformational leadership as a significant predictor of readiness to change and it proved relevant in empowering knowledge sharing quality, which in turn affects organizational performance. Furthermore, the effects of both two mediating variables was also examined, and only readiness to change significantly influenced the relationship between predictors of transformational leadership and organizational performance. The findings of this study showed the need for transformational leaders as the research focused on understanding the differences in employee character. This is required to encourage better performance by empowering quality knowledge dissemination mechanisms, with continuous in-house training activities. Therefore, the model adopted in this research and the hypotheses prove the direct effect of transformational leadership on organizational performance, achievable through the mediating role of readiness to change.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.20 no.3
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• pp.269-278
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• 2022

The buffer is a critical barrier component in an engineered barrier system, and its purpose is to prevent potential radionuclides from leaking out from a damaged canister by filling the void in the repository. No experimental parameters exist that can describe the buffer expansion phenomenon when Kyeongju bentonite, which is a buffer candidate material available in Korea, is exposed to groundwater. As conventional experiments to determine these parameters are time consuming and complicated, simple swelling pressure tests, numerical modeling, and machine learning are used in this study to obtain the parameters required to establish a numerical model that can simulate swelling. Swelling tests conducted using Kyeongju bentonite are emulated using the COMSOL Multiphysics numerical analysis tool. Relationships between the swelling phenomenon and mechanical parameters are determined via an artificial neural network. Subsequently, by inputting the swelling tests results into the network, the values for the mechanical parameters of Kyeongju bentonite are obtained. Sensitivity analysis is performed to identify the influential parameters. Results of the numerical analysis based on the identified mechanical parameters are consistent with the experimental values.

• Korean Journal of Agricultural Science
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• v.9 no.1
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• pp.269-274
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• 1982

These studies were conducted to evaluate the bulk pasteurization system in comparison with the conventional mushroom growing technique of and to establish the phase II fermentation method for the system. The results obtained were as follows. 1. From the mushroom compost peak-heated in the bulk pasteurization system higher mushroom yield was obtained than that of the conventional method. 2. The compost fermented in the bulk pasteurization system showed poor mycelial growth and low crop. It was caused by the imperfect blower and its operation, not by ununiform moisture content of the compost and ununiform filling. 3. A bulk pasteurization system which modified the mushroom house was not proper for the fermentation of the mushroom compost and the sporophore yields were lower than the standard pasteurization system. 4. In the bulk pasteurization system, peak-heating time, phase II period and quality of the compost were influenced by the air temperature but its effects were not more significant than those of the conventional method. 5. During phase II in the bulk pasteurization system moisture content of the compost at filling did not affect the fermentation of the compost.

• Membrane Journal
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• v.27 no.5
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• pp.415-424
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• 2017

Commonly cation exchange membranes have been used for vanadium redox flow batteries. However, a severe vanadium ion cross-over causes low energy efficiency. Thus in this study, we prepared 3 different anion exchange membranes to investigate the effect on the membrane properties such as vanadium ion cross-over and long term stability. The base membranes were prepared by an electrolyte pore filling technique using vinyl benzyl chloride (VBC), divinylbenzene (DVB) within a porous polyethylene (PE) substrate. Then 3 different functional amines were introduced into the base membranes, respectively. These resulting membranes were evaluated by physico-chemical properties such as ion exchange capacity, dimensional stability, vanadium ion cross-over and membrane area resistance. Conclusively, TEA-functionalized membrane showed longest term stability than other membranes although all the membranes are similar to coulombic efficiency.