• 대한치과기공학회지
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• 제41권2호
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• pp.71-80
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• 2019

Purpose: In this study, to evaluate the effect of oxide changes on the shear bond strength according to the composition of Ni-Cr alloys for porcelain fused matal crown, T-4 alloys, Zeroy alloys and Zeroy-X alloys were selected. Methods: 20 specimens were fabricated using selected Ni-Cr alloys and porcelain powders. A Ni-Cr alloy having a diameter of 5 mm and a height of 25 mm was produced and the metal surface was polished. Porcelain powder was fired on the polished metal surface to a diameter of 5 mm and a height of 3 mm. The experiment group consisted of three groups, T-4(TNA), Zeroy(ZNA) and Zeroy-X(ZXA). The fabricated specimens were mounted on a jig of a universal testing machine(UTM) and fracture strength was measured by applying a shear force at a UTM crosshead speed of 0.5 mm/min. The fracture strength was calculated as the bond strength between the porcelain and the alloy. The surface of the fractured alloy was analyzed by X-ray diffraction(XRD) and scanning electron microscopy(SEM), and the components of the oxide were measured by energy dispersive X-ray spectroscopy(EDX) line profile method. Results: In SEM, XRD and EDX analysis, yttrium tended to increase the mechanical and chemical bonding forces. The shear bond strength of ZXA group containing yttrium showed the highest value at 27.53 MPa. Conclusion: Based on the results of this study, it is considered that the yttrium-added Ni-Cr alloy is clinically acceptable in porcelain shear bond strength.

• 한국재료학회지
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• 제31권10호
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• pp.552-561
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• 2021

For the purpose of manufacturing a high efficiency TiO₂ photocatalyst, B-doped TiO₂ photocatalysts are synthesized using a plasma electrolytic oxidation method in 0.5 M H₂SO₄ electrolyte with different concentrations of H₃BO₃ as additive. For the B doped TiO₂ layer fabricated from sulfuric electrolyte having a higher concentration of H₃BO₃ additive, the main XRD peaks of (101) and (200) anatase phase shift gradually toward the lower angle direction, indicating volume expansion of the TiO₂ anatase lattice by incorporation of boron, when compared with TiO₂ layers formed in sulfuric acid with lower concentration of additive. Moreover, XPS results indicate that the center of the binding energy peak of B1s increases from 191.45 eV to 191.98 eV, which suggests that most of boron atoms are doped interstitially in the TiO₂ layer rather than substitutionally. The B doped TiO₂ catalyst fabricated in sulfuric electrolyte with 1.0 M H₃BO₃ exhibits enhanced photocurrent response, and high efficiency and rate constant for dye degradation, which is ascribed to the synergistic effect of the new impurity energy band induced by introducing boron to the interstitial site and the improvement of charge transfer reaction.

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

• 대한금속재료학회지
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• 제56권12호
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• pp.900-909
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• 2018

A $ZnO/TiO_2$ photocatalyst decorated with PbS quantum dots (QDs) was synthesized to achieve high photocatalytic efficiency for the decomposition of dye in aqueous media. A $TiO_2$ porous layer, as a precursor photocatalyst, was fabricated using micro-arc oxidation, and exhibited irregular porous cells with anatase and rutile crystalline structures. Then, a ZnO-deposited $TiO_2$ catalyst was fabricated using a zinc acetate solution, and PbS QDs were uniformly deposited on the surface of the $ZnO/TiO_2$ photocatalyst using the successive ionic layer adsorption and reaction (SILAR) technique. For the PbS $QDs/ZnO/TiO_2$ photocatalyst, ZnO and PbS nanoparticles are uniformly precipitated on the $TiO_2$ surface. However, the diameters of the PbS particles were very fine, and their shape and distribution were relatively more homogeneous compared to the ZnO particles on the $TiO_2$ surface. The PbS QDs on the $TiO_2$ surface can induce changes in band gap energy due to the quantum confinement effect. The effective band gap of the PbS QDs was calculated to be 1.43 eV. To evaluate their photocatalytic properties, Aniline blue decomposition tests were performed. The presence of ZnO and PbS nanoparticles on the $TiO_2$ catalysts enhanced photoactivity by improving the absorption of visible light. The PbS $QDs/ZnO/TiO_2$ heterojunction photocatalyst showed a higher Aniline blue decomposition rate and photocatalytic activity, due to the quantum size effect of the PbS nanoparticles, and the more efficient transport of charge carriers.

• 한국정보통신학회논문지
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• 제23권11호
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• pp.1384-1390
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• 2019

본 논문은 머신비전기반 자동검사를 위한 대상객체의 인식방향성 개선 연구로서, 영상카메라에 의한 자동 비전검사의 과정에서 제한성이 따르는 대상 객체의 인식방향성을 개선하는 방법을 제안한다. 이를 통하여 머신비전 자동검사에서 시험대상물의 위치와 방향에 상관없이 검사대상의 영상을 검출할 수 있게 함으로써 별도 검사지그의 필요성을 배제하고 검사과정의 자동화 레벨을 향상시킨다. 본 연구에서는 검사대상으로서 와이어 하네스 제조과정에서 실제 적용할 수 있는 기술과 방법을 개발하여 실제 시스템으로 구현한 결과를 제시한다. 시스템구현 결과는 공인기관의 평가를 통하여, 정밀도, 검출인식도, 재현률 및 위치조정 성공률에서 모두 성공적인 측정결과를 얻었고, 당초 설정하였던 10종류의 컬러구별 능력, 1초 이내 검사시간, 4개 자동모드 설정 등에서도 목표달성을 확인하였다.

• 한국정보통신학회논문지
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• 제26권4호
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• pp.556-561
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• 2022

본 논문에서는 선박 용접공정에 사용되는 장비에 전력선통신 기술을 접목하고 금속블록을 통신매체로 사용하는 블록매체통신시스템을 제시한다. 여기서는 디지털 피더와 금속블록을 지지하는 핀지그에 유도성 커플러를 설치하고, 피더에 연결된 용접건에서 발생되는 전류에 정보신호를 더하여 금속블록에 인가함으로써 작업이 시작되면 현장에서 발생되는 정보를 상황실 서버에 실시간 전송한다. 현장시험 결과, 제시된 블록매체통신시스템의 송신부에서 전송된 데이터는 상황실 서버컴퓨터에 정확하게 수신되는 것을 확인하였다. 따라서 제시된 시스템은 기존 용접공정에 대한 변경 없이 구축이 가능하므로 향후 조선소 스마트 팩토리화를 통한 조선산업의 경쟁력 강화에 도움이 될 것으로 기대된다. 또한 전자파 차폐 환경이나 밀폐된 공간에서 작업자에게 발생할 수 있는 응급상황에 신속한 대처가 가능하므로 산업재해 예방효과도 클 것으로 사료된다.

• Journal of Interdisciplinary Genomics
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• 제4권1호
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• pp.1-6
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• 2022

Purpose: Mastectomy is performed as a surgical treatment for patients with breast cancer who have the BRCA 1/2 mutation. In this study, we have reported the trends in Korea for both immediate breast reconstruction and prophylactic mastectomy. Methods: This retrospective study was conducted from 2019 to 2021. Both skin-sparing mastectomy and immediate implant-based breast reconstruction with prepectoral and/or subpectoral techniques were performed in five patients with BRCA 1/2 mutations. Data on age; body mass index; cancer stage; BRCA 1/2 mutation; estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 expression; diagnosis; and complications were collected. Results: The average (±standard deviation [SD]) age was 44.0±6.48 years old; BMI 24.5±2.25 kg/m²; and breast volumes were 365.8±70.34 and 382.4±96.33 cc for right and left ones, respectively. The BRCA 1 and 2 were diagnosed in four and one patients, respectively. The estrogen and progesterone receptors and human epidermal growth factor receptor 2 were detected in one (20%), one (20%), and three (60%) patients, respectively. The applied implant-based breast reconstruction techniques for ten breasts were subpectoral technique (n=7, 70%) and prepectoral technique (n=3, 30%). For the cancer stage, those with I, II, and III stages were one (20%), two (40%), and one (20%), respectively. There were no major complications such as Infection, seroma. Conclusion: When mastectomy is performed as surgical treatment in BRCA 1/2 mutation positive breast cancer patients, it is possible to obtain a better outcome with both implant-based breast reconstruction and different circumstances between breast cancer and contralateral breast.

• 대한두개안면성형외과학회지
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• 제23권1호
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• pp.29-33
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• 2022

Background: There have been many reports of nasal bone fractures in adults, but there are few clinical reports of them in adolescents, although adolescence is the main growth period of the nasal bone. In addition, previous studies have tended to classify and describe child and adolescent nasal fractures in the same category. The aim of this study was to identify the clinical aspects of nasal fractures in adolescents, and to evaluate the characteristics of nasal fractures in the growth period. Methods: Our institution's database was reviewed to extract data on adolescent patients between the age of 13 to 18 who had isolated nasal bone fractures from March 2012 to February 2020. The study excluded patients with other facial fractures, previous facial fractures, or congenital deformities. Results: This study included 243 boys and 26 girls. Interpersonal violence and sports-related accidents accounted for 85 and 79 cases, respectively. There were 128 frontal impact injuries and 132 lateral impact injuries, and 97 patients had accompanying septal fractures. An accompanying septal fracture was present in 36.06% of all patients, but in 51.20% of those who underwent surgery. Conclusion: The prevalence of adolescent nasal fractures was significantly higher in boys, to a greater extent than observed for pediatric or adult fractures. The main causes of fractures were interpersonal violence and sports-related accidents. An explanation for these results is that adolescent boys are more prone to have violent accidents or companionship with active sports than other age or sex groups, leading to substantially more fractures.

• Journal of Interdisciplinary Genomics
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• 제4권2호
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• pp.35-38
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• 2022

Background: Prader-Willi syndrome (PWS) is a complex genetic disease associated with growth impairment, severe obesity and metabolic dysfunctions. High proportion of PWS patients are born small for gestational age (SGA) than normal children, which also increase the risk of growth impairment and metabolic dysfunction in PWS. We aimed to compare growth outcome and metabolic profiles between SGA and appropriate for gestational age (AGA) PWS patients. Methods: Data of 55 PWS children and adults aged more than 2 years old (32 male and 23 female, age 2-18.8 years) from single center were studied. Only patients who were treated with GH were included. The clinical characteristics and laboratory findings were reviewed retrospectively. Results: Among 55 subjects, 39 had 15q11-13 deletion and 16 had uniparental disomy (UPD). Twenty (36.3%) were born SGA. All patients received GH treatment, and 11 (20%) discontinued GH treatment. Mean age at GH treatment initiation was 2.5 (range 0.3-12.4) years, and mean duration of treatment was 6.3 (range 1.0-11.3) years. Current height-SDS (-0.36 vs -0.16) and BMI-SDS (1.44 vs 1.33) did not differ between AGA and SGA group. Two patients in SGA group, but none in AGA group had diabetes mellitus. Mean glucose level was also higher in SGA group (100.1 vs 114.4 mg/dL). Conclusion: Our report gives an overview of growth profile and metabolic dysfunctions recorded in GH treated PWS patients. Growth profile did not differ between AGA and SGA group. Glucose level was higher in SGA group, so more careful monitoring and prevention for DM will be required in SGA group.

• 한국정보통신학회논문지
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• 제26권10호
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• pp.1545-1550
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• 2022

본 논문에서는 최근 물류, 제조업 등 다양한 산업군에서 활용되는 AMR(Autonomous Mobile Robot)의 LiDAR 고장 시 교체 시간을 최소화하는 방법에 대해 연구하였다. 이를 위해 일반적인 LiDAR 교체 프로세스를 정의하고 퀵-체인지 기구에 기반한 새로운 프로세스를 제안하였다. 실험은 자동차 제조 기업 공장 내 적용을 위해 개발된 AMR을 활용해 수행하였으며, 새로운 프로세스 적용 시 24분 내 LiDAR 교체가 가능하며 일반적 프로세스 대비 약 76% 이상 단축됨을 확인할 수 있었다. 결과적으로, 제안된 프로세스의 적용을 통해 AMR의 비가동 및 전체적인 공정 지연을 최소화할 수 있다.