• 치위생과학회지
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• 제20권4호
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• pp.261-268
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• 2020

Background: A comprehensive history taking at the first visit could be an important start of treatment. This study investigated the current status of the initial history taking for dental patients in S area, and the implementation and importance of the initial history taking process. Based on this, we intend to provide basic data for the development of organized and standardized questionnaires in dental clinics. Methods: In April 2019, 303 dental clinics in S area were targeted and special dental clinics (orthodontics, children, and disabled) were excluded. The questionnaire consisted of 29 items, including general characteristics, systemic disease history, dental history, oral health behaviors, and the data were obtained through self-administered questionnaire. Results: Initial history taking was mostly implemented using oral and questionnaire at the time of the first visit. Systemic disease history, dental history, and oral health behaviors differed in the work experience of the dental clinic staff. As a result of analyzing the importance according to implementation, there were significant differences in all questions except drug-related items. The importance of the questionnaire was highly recognized, but the reason it was not actually implemented was because of existing the questionnaire in the clinic and lack of time. Conclusion: Considering that the initial history taking implementation rate showed low, it is necessary to develop standardize a practical questionnaire and interview skills for dental clinics in the future. In addition, training programs should be provided to dental staff that can recognize the importance of initial history taking questionnaires and contribute to active implementation.

• 대한금속재료학회지
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• 제48권3호
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• pp.241-247
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• 2010

In order to develop the vacuum distillation process of magnesium alloy scrap, a fundamental study on the evaporation behavior of magnesium alloy (AM50) scrap melt was carried out. Melt temperature, pressure, reaction time, and initial specific surface area of melt were considered as experimental variables. The evaporation rate of magnesium increased with the increase of melt temperature and initial specific surface area of melt, and with the decrease of the pressure. The activation energy of magnesium evaporation reaction calculated by an Arrhenius plot decreased with the decrease of the pressure and with the increase of the initial specific surface area of melt. An empirical equation was derived for the evaporation rate of magnesium from AM50 alloy melt.

• The Journal of Advanced Prosthodontics
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• 제6권3호
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• pp.177-184
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• 2014

PURPOSE. The aim of this study was to measure the changes on the marginal and internal adaptation of zirconia based anterior fixed partial dentures after the porcelain firing process. MATERIALS AND METHODS. A total of 34 anterior fixed partial dentures using LAVA CAD/CAM system (3M ESPE, Germany) were applied. Two silicone replicas were obtained: one is obtained before porcelain firing process (initial) and the other is obtained after porcelain firing process (final), followed by the examination under a binocular stereomicroscope. Kruskal Wallis and Wilcoxon Signed Ranks tests were used for the statistical analysis (P<.05). RESULTS. No statistically significant difference was found between initial and final marginal gap values (P>.05). At the internal gap measurements, final marginal area values ($59.54{\mu}m$) were significantly lower than the initial marginal area values ($68.68{\mu}m$)(P<.05). The highest and the lowest internal gap values were observed at the incisal/occlusal area and at the marginal area, respectively. In addition, lower internal gap values were obtained for canines than for central incisors, lateral incisors and premolars at the incisal area (P<.05). CONCLUSION. The firing cycles did not affect the marginal gap of Lava CAD/CAM system, but it is controversial for the internal gap.

• 한국해양공학회지
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• 제13권3호통권33호
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• pp.12-20
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• 1999

In this paper, method for mapping a three-dimensional shape into the two-dimensional plane will be introduced. This method is referred to geometric modelling and means a transformation between the flat sheet and final surface. The initial blank shape represents the original configuration of the final shape formed into three dimensional surface. The initial constant constant area mapping hypothesis was used in this paper. This technique will be applied to the basic data for an interactive computer design capable of dealing with typical stamping process, including deep parts and complex shapes.

• 한국산업융합학회 논문집
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• 제4권4호
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• pp.427-432
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• 2001

The purpose of study is to examine the sensitivity of the rate of degradation to initial TCE concentration and iron concentration in the solution. The batch tests were executed to assess the degradation rate at varying initial conditions. First order rate constants($k_a$) were more rapid with the lower initial TCE concentration, Howere the correleation was not always linear between $k_a$ and initial TCE concentration. $k_a$ was proportionally increased as the increasing surface area. It implied that the effective reactive surface area acted as the limiting factor on the reductive dechlorination of TCE by iron.

• 자원환경지질
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• 제33권4호
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• pp.309-320
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• 2000

Aperture is an important parameter for determining the hydraulic characteristics of fractured media. In this study the topography of artificial rock joint surface was measured using 3D laser profilometer to analyze the aperture distribution. The initial aperture distribution was determined when the contact area became one percent of total joint surface. The initial aperture distribution of granite joint, with the mean value of 0.78 mm and the standard deviation of 0.34 mm was much different from that of the marble joint, with the mean value of 0.57 mm and the standard deviation of 0.26 mm. Apertures of both granite and marble showed normal distributions. Aperture distribution with the contact area of 25% was also analyzed. Mean value was decreased to one third compared to the initial aperture, but the standard deviation was decreased slightly. To determine the spatial correlation of the aperture distribution variogram analysis was carried out on the initial aperture data. Most experimental variograms were fitted well with exponential model. It is expected that the measured aperture characteristics can be used for stochastic analysis of fluid flow through rock joints.

• 로봇학회논문지
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• 제15권1호
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• pp.16-23
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• 2020

This paper describes an alignment algorithm that estimates the initial heading angle of AUVs (Autonomous Underwater Vehicle) for starting navigation in a sea area. In the basic dead reckoning system, the initial orientation of the vehicle is very important. In particular, the initial heading value is an essential factor in determining the performance of the entire navigation system. However, the heading angle of AUVs cannot be measured accurately because the DCS (Digital Compass) corrupted by surrounding magnetic field in pointing true north direction of the absolute global coordinate system (not the same to magnetic north direction). Therefore, we constructed an experimental constraint and designed an algorithm based on extended Kalman filter using only inertial navigation sensors and a GPS (Global Positioning System) receiver basically. The value of sensor covariance was selected by comparing the navigation results with the reference data. The proposed filter estimates the initial heading angle of AUVs for navigation in a sea area and reflects sampling characteristics of each sensor. Finally, we verify the performance of the filter through experiments.

• 자원환경지질
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• 제19권spc호
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• pp.43-52
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• 1986

Kaolin-pyrophyllite are locally abundant in the three hydrothermal areas at Yangsan-Tongnae area, Hadong-Sancheong area and Haenam area, deposits are originally composed of acidic volcanic rocks and anorthositic rocks in Hadong-Sancheong area. The clay deposits are formed in the near shallow depths environment through acid hydrothermal alteration. Hadong-Sancheong halloysite deposits are formed by alteration of anorthosite. These differences are mainly on the various country rocks, geological structure and properties of hydrothermal solutions. Country rock is mostly underlain by rhyolitic tuffaceous and anorthositic rocks and a large number of clay deposits were formed during volcanic activity through upper Cretaceous-lower Tertiary. Intrusive rocks is broadly distributed in this area and clay deposits are variable in shapelayer and funnel typed. Zonal pattern of mineral assemblage is as follows, Yangsan-Tongnae deposits-kaolinite, pyrophyllite, dumortierite, andalusite and sericite, Hadong-Sancheong-mostly halloysite, and Haenam-dickite, pyrophyllite, alunite and diaspore. The difference in the zonal pattern of altered rock is considered to depend on differences in the initial acidity of related hydrothermal solution, initial acidity was controlled by the oxygen fugacity.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 1999년도 추계학술발표대회 논문집
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• pp.149-153
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• 1999

During a hemisphere-type compression molding, the wrinkles are caused by complex stress condition. It is very important to clarify the degree of wrinkles in order to have good products. In this paper, the effects of numbers of needling and initial area on the degree of wrinkles are studied. the degree of wrinkle is expressed as nonhomogeneity.

• International Journal of Automotive Technology
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• 제7권5호
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• pp.519-526
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• 2006

For investigating the effect of fuel stratification on flame propagation, initial flame development and propagation were visualized under different axially stratified states in a port injection SI engine. Stratification was controlled by the combination of the port swirl ratio and injection timing. Experiments were performed in an optical single cylinder engine modified from a production engine and images were captured through the quartz window mounted in the piston by an intensified CCD camera. Firstly in this paper, the characteristics under no port-generated swirl condition, i.e. normal conventional case was studied. Under various stratified conditions, flame images were captured at the pre-set crank angles. These were averaged and processed to characterize the flames propagation. The flame stability was estimated by the weighted average of flame area and luminosity. The stability was also evaluated through the standard deviation of flame area and propagation distance, and mean absolute deviation of propagating direction. Results show that stratification state according to injection timing do not affect on the direction of flame propagation. The flame development and the initial flame stability are strongly dependent on the stratified conditions and the initial flame stability is closely related to the engine stability and lean misfire limit.