• The Journal of Advanced Prosthodontics
• /
• 제13권3호
• /
• pp.136-143
• /
• 2021

Purpose. This study aimed to evaluate the effect of repeated use of an implant handpiece under an implant placement torque (35 Ncm) and overloading torque condition (50 Ncm) on an output torque. Materials and Methods. Two types of implant handpiece systems (Surgicpro/X-DSG20L [NSK, Kanuma, Japan] and SIP20/CRB46LN [SAESHIN, Daegu, South Korea]) were used. The output torque was measured using a digital torque gauge. The height and angle (x, y, and z axes) of the digital torque gauge and implant handpiece were adjusted through a jig for passive connection. The experiment was conducted under the setting torque value of 35 Ncm (implant placement torque) and 50 Ncm (overloading torque condition) and 30 times per set; a total of 5 sets were performed (N = 150). For statistical analysis, the difference between the groups was analyzed using the Mann-Whitney U test and the Friedman test was used to confirm the change in output torque (α=.05). Results. NSK and SAESHIN implant handpieces showed significant differences in output torque results at the setting torques of 35 Ncm and 50 Ncm (P<.001). The type of implant handpiece and repeated use influenced the output torque (P<.001). Conclusion. There may be a difference between the setting torque and actual output torque due to repeated use, and the implant handpiece should be managed and repaired during long-term use. In addition, for successful implant results in dental clinics, the output torque of the implant handpiece system should be checked before implant placement.

• IEIE Transactions on Smart Processing and Computing
• /
• 제3권2호
• /
• pp.65-73
• /
• 2014

An overall responding security-centered framework is necessary required for infringement accidents, failures, and cyber threats. On the other hand, the correspondence structures of existing administrative, technical, physical security have weakness in a system responding to complex attacks because each step is performed independently. This study will recognize all internal and external users as a potentially threatening element. To perform connectivity analysis regarding an action, an intelligent convergence security framework and road map is suggested. A suggested convergence security framework was constructed to be independent of an automatic framework, such as the conventional single solution for the priority defense system of APT of the latest attack type, which makes continuous reputational attacks to achieve its goals. This study suggested the next generation convergence security framework to have preemptive responses, possibly against an APT attack, consisting of the following five hierarchical layers: domain security, domain connection, action visibility, action control, and convergence correspondence. In the domain, the connection layer suggests a security instruction and direction in the domains of administrative, physical and technical security. The domain security layer has consistency of status information among the security domain. A visibility layer of an intelligent attack action consists of data gathering, comparison and decision cycle. The action control layer is a layer that controls the visibility action. Finally, the convergence corresponding layer suggests a corresponding system of before and after an APT attack. The administrative security domain had a security design based on organization, rule, process, and paper information. The physical security domain is designed to separate into a control layer and facility according to the threats of the control impossible and control possible. Each domain action executes visible and control steps, and is designed to have flexibility regarding security environmental changes. In this study, the framework to address an APT attack and load map will be used as an infrastructure corresponding to the next generation security.

• The Journal of Advanced Prosthodontics
• /
• 제6권1호
• /
• pp.46-52
• /
• 2014

PURPOSE. The aim of this study was to evaluate the interface accuracy of computer-assisted designed and manufactured (CAD/CAM) titanium abutments and implant fixture compared to gold-cast UCLA abutments. MATERIALS AND METHODS. An external connection implant system (Mark III, n=10) and an internal connection implant system (Replace Select, n=10) were used, 5 of each group were connected to milled titanium abutment and the rest were connected to the gold-cast UCLA abutments. The implant fixture and abutment were tightened to torque of 35 Ncm using a digital torque gauge, and initial detorque values were measured 10 minutes after tightening. To mimic the mastication, a cyclic loading was applied at 14 Hz for one million cycles, with the stress amplitude range being within 0 N to 100 N. After the cyclic loading, detorque values were measured again. The fixture-abutment gaps were measured under a microscope and recorded with an accuracy of ${\pm}0.1{\mu}m$ at 50 points. RESULTS. Initial detorque values of milled abutment were significantly higher than those of cast abutment (P<.05). Detorque values after one million dynamic cyclic loadings were not significantly different (P>.05). After cyclic loading, detorque values of cast abutment increased, but those of milled abutment decreased (P<.05). There was no significant difference of gap dimension between the milled abutment group and the cast abutment group after cyclic loading. CONCLUSION. In conclusion, CAD/CAM milled titanium abutment can be fabricated with sufficient accuracy to permit screw joint stability between abutment and fixture comparable to that of the traditional gold cast UCLA abutment.

• 복식
• /
• 제65권4호
• /
• pp.124-136
• /
• 2015

Xinjiang Uygur Autonomous Region is the area with the most Muslim populations in China and the costume of this ethnic minority group was influenced from its surrounding environment and religion. Headgear is one of the important costume elements of Muslim ethnic minority such as Kazakh, Kirghiz, Uzbek, and Tadzhik people, and each group has developed narious forms of it. Especially, we can notice characteristics of headgear in Xinjiang Uygur and four ethnic minority groups through women's headgear pursuant to motive of wear, classification of type, differences and comparability with other areas. Thus, purpose of this study is to investigate women's headgear of Muslim ethnic minority in Xinjiang Uygur Autonomous Region. Based on local data at the Xinjiang Uygur Museum, the study referred to Chinese ethnic minority costume and literature data as well as advanced researches related to Islam, and analyzed characteristics of women's headgear of four ethnic groups in connection with Muslim formation background in Xinjiang Uygur. Women's headgear of Muslim ethnic minority in Xinjiang Uygur can be largely divided into three types; cylindrical, conical and hood type. Headgear was influenced not only by natural environment and weather for protection of body, but also by Islam. Along with strong desire for decoration and expression of racial features, it was used as a means of race discrimination and representation of identity. The religion of Islam within these four ethnic groups grew in accordance with tradition of existing nomadic tribes and regional characteristics, and women's headgear developed in various ways added with religious precepts and nomadic features. Taking everything into consideration, it is found that women's headgear of Kazakh, Kirghiz, Uzbek, and Tadzhik people developed, adopting their own living style and features of minority races instead of remaining identical to the headgear type of Muslim countries in other area.

• Journal of Advanced Marine Engineering and Technology
• /
• 제39권4호
• /
• pp.405-411
• /
• 2015

최근 저탄소 녹색성장 및 그린에너지 개발 정책에 힘입어 외연기관의 일종으로 스털링엔진에 대한 관심이 고조되고 있다. 스털링엔진은 크게 ${\alpha}$, ${\beta}$, ${\gamma}$-type의 3가지 방식으로 구분되어지며 그 중 ${\gamma}$-type 엔진의 설계가 용이하고 다양한 적용이 가능하다는 특징이 있음에도 실린더와 크랭크간의 접속거리 문제로 인하여 ${\alpha}$, ${\beta}$-type에 비하여 용적을 크게 차지하는 문제가 있었다. 이를 해결하기 위한 한 방안으로 주로 ${\alpha}$-type에 적용하는 Yoke crank를 응용하면 용적을 줄임과 동시에 실린더의 병렬화에도 유리하다. 금번 연구에서는 기존의 Ross Yoke crank 설계기법에서 개선하여 ${\gamma}$-type 스털링엔진의 Yoke crank 설계를 더욱 단순하고 효율적으로 적용할 수 있는 방법을 제시하였다.

• Advanced Composite Materials
• /
• 제16권1호
• /
• pp.1-10
• /
• 2007

Composite materials consisting of crushed carbon fiber reinforced plastics (CFRP) pieces and acrylonitrile-butadiene-styrene (ABS) resin were prepared by an injection mold method to solve the problem of recycling of CFRP. The electrical properties, such as electrical resistivity, alternating current impedance and electromagnetic interference (EMI) shielding effect, were measured for the composites. The electrical resistivity of the composites showed a percolation type of conduction behavior and no difference between parallel and perpendicular to the injection direction was observed for CFRP content higher than the critical value. Measurement of alternating current impedance revealed that the conduction mechanism is attributed to the direct conductive paths generated by distributed carbon fibers; however, strong frequency dependence of the impedance was observed for the CFRP content near the critical one. The frequency dependence of the impedance is caused by the inter-fiber connection and can be expressed as a simple equivalent circuit. The absorption component of shielding effect (SE) was smaller than the expected value estimated from its resistivity. The decline of SE is thought to be caused by the decrease in effective thickness due to fiber orientation.

• Journal of Power Electronics
• /
• 제13권3호
• /
• pp.329-338
• /
• 2013

In this paper, the charging characteristics of series resonant type high voltage capacitor chargers considering the transformer stray capacitance have been studied. The principles of operation for the four operational modes and the mode changes for the four different switching frequency sections are explained and analyzed in the range of switching frequency below the resonant frequency. It is confirmed that the average charging currents derived from the above analysis results have non-linear characteristics in each of the four modes. The resonant current, resonant voltage, charging current, and charging time of this capacitor charger as variations of the switching frequency, series parallel capacitance ratio ($k=C_p/C_s$), and output voltage are calculated. From the calculation results, the advantages and disadvantages arising from the parallel connection of this stray capacitance are described. Some methods to minimize charging time of this capacitor charger are suggested. In addition, the results of a comparative test using two transformers whose stray capacitances are different are described. A 1.8 kJ/s prototype capacitor charger is assembled with a TI28335 DSP controller and a 40 kJ, 7 kV capacitor. The analysis results are verified by the experiment.

• International journal of advanced smart convergence
• /
• 제11권1호
• /
• pp.55-63
• /
• 2022

Although research on the leader's or speaker's voice has been continuously conducted, existing research has a single point of view. Sound analysis of voice characteristics has been studied from engineering perspectives, and leadership trait theory has been studied from a business perspective. Convergence studies on leader voice and member cognition are being attempted today. Convergence research on voice has a positive effect on refinement of voice analysis, diversification of voice use, and establishment of voice utilization strategy. This study explains the current flow of research on convergence between speaker's voice and listener's perception, and suggests a direction for the future development of voice fusion research. Furthermore, in connection with AI in the 4th industrial age, new attempts for voice research are sought. First, advances in AI focus on strategically generating the voices needed for individual situations. Second, the voice corrected in real time will support the leader and speaker to utilize the desired voice type. Third, voices through AI based on big data will affect the cognition, attitude and behavior of individual listeners who members, customers, and students in more diverse situations. The purpose and significance of this study is to suggest the way to research the leader's voice recognized by members, and to suggest a method that can be applied in various situations.

• 구강회복응용과학지
• /
• 제31권1호
• /
• pp.33-44
• /
• 2015

목적: 본 연구는 platform matching, platform switching을 시행한 임플란트의 변연골 소실을 비교하여 platform switching 개념의 임상적 의의를 평가하고자 한다. 연구 재료 및 방법: 원광대학교 치과병원 임플란트 센터에서 치료를 진행한 환자를 대상으로 임플란트 식립 시기, 직경, 길이, 지대주 연결방법 및 보철물 연결고정 유무를 조사하였다. 변연골 소실량을 측정하기 위해서 Emago advanced v5.6 프로그램을 사용하여 임플란트 식립 시와 가장 최근 내원 시의 치근단 방사선 사진을 비교하였다. 결과: 환자 82명의 임플란트 150개를 대상으로 6 - 63개월 동안 관찰한 결과 platform matching 임플란트는 $1.16{\pm}0.54mm$, platform switching 임플란트는 $0.68{\pm}0.27mm$의 변연골 소실을 나타내었다. 결론: Platform switching을 시행함으로써 임플란트의 변연골 소실을 줄이는 효과가 있는 것으로 사료된다.

• Molecular & Cellular Toxicology
• /
• 제5권4호
• /
• pp.298-303
• /
• 2009

(-)-Epigallocatechin-3-gallate (EGCG), a major flavonoid in green tea has multiple health benefits including chemoprevention, anti-inflammatory, anti-diabetic, and anti-obesity effects. In connection with these effects, EGCG can be a candidate to help the treatment of metabolic diseases. Metformin is a widely used anti-diabetic drug regulating cellular energy homeostasis via AMP-activated protein kinase (AMPK) activation. Therefore, the combination of metformin with EGCG may have additive or synergistic effects on treatment of type 2 diabetes. Nevertheless, there is no report for the pharmacokinetic and/or pharmacodynamic interaction of EGCG with metformin. Here, we evaluated the pharmacokinetic and pharmacodynamic interaction between metformin and EGCG in rats. Pharmacokinetics parameters of metformin were measured after oral administration of metformin in rats pre-treated with EGCG (10 mg/kg) or saline for 7 days. The results showed that there is no significant difference in pharmacokinetic parameters between saline control and EGCG-treated group. In addition, the hepatic AMPK activation by metformin in EGCG-treated rats was also similar to the control. The lack of additive effects of EGCG on AMPK activation or intracellular uptake of metformin was also evaluated in cells in the presence or absence of EGCG. Treatment of HepG2 cells with EGCG inhibited the metformin-induced AMPK activation. Combined results suggested that EGCG has no effect on the pharmacokinetics of metformin but may contribute to metformin action.