• 대한치과교정학회지
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• 제42권4호
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• pp.218-224
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• 2012

Objective: To investigate the resistance to sliding (RS) in self-ligating and conventional ligation bracket systems at 5 different second-order bracket angulations by using low-stiffness alignment wires in a 3-bracket experimental model and to verify the performance of the main RS components in both systems when these wires are used. Methods: Interactive self-ligating brackets with closed and open slides were used for the self-ligating (SL) and conventional ligation (CL) groups, respectively; elastomeric ligatures (1 mm inner diameter) were used in the latter system. The alignment wire used was 0.014 inch heat-activated NiTi (austenitic finish temperature set at $36^{\circ}C$ by the manufacturer). A custom-made testing machine was used to measure frictional resistance. Tests were repeated 5 times at every angulation simulated. All data were analyzed statistically. Results: The RS increased significantly with increasing angulation in both SL and CL groups (p < 0.0001). However, the RS values were significantly higher at every angulation (p < 0.0001) in the CL group. Conclusions: Despite the relevance of the binding phenomenon, ligation forces predominantly affect the RS when lowstiffness alignment wires are used.

• 대한치과교정학회지
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• 제45권2호
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• pp.89-94
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• 2015

Objective: To test the null hypothesis that SmartClip self-ligating brackets are more effective than conventional brackets for initial mandibular alignment and identify influential factors. Methods: Fifty patients were randomly allocated to two equal treatment groups by using an online randomization program: self-ligating group (SmartClip brackets) and conventional group (Gemini brackets). The archwire sequence was standardized. Changes in anterior irregularity index, intercanine width, and intermolar width were assessed on plaster models at 8th and 16th weeks. Changes in incisor position and inclination were assessed on lateral cephalometric radiographs at 16 weeks. Intragroup and intergroup comparisons were performed with paired t-test and Student's t-test, respectively. Multiple linear regression was performed to identify variables affecting improvement in anterior ambiguity. Results: Data of 46 patients were analyzed; those missing an appointment (n = 2) or showing bracket breakage (n = 2) were excluded. Incisor inclination (p < 0.05), intercanine width (p < 0.05), and intermolar width (p > 0.05) increased at 8 and 16 weeks in both the groups; no significant intergroup differences were noted (p > 0.05). Initial anterior irregularity index and intercanine width change were significantly associated with improvement in anterior irregularity (p < 0.001). Conclusions: The null hypothesis was rejected. Bracket type has little effect on improvement in anterior ambiguity during initial mandibular alignment.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.645-647
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• 2009

We investigated vertical liquid crystal (LC) alignment effects of a self-assembled-monolayer (SAM) prepared on an anisotropic $SiO_2$ surface where the field-induced LC reorientation produced a uniform single domain texture. We compared the results with the homeotropic-to-random planar reorientation results shown in LCs aligned on a SAM surface prepared on an isotropic $SiO_2$ surface.

• International Journal of Aeronautical and Space Sciences
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• 제3권1호
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• pp.86-94
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• 2002

The initial alignment of inertial platform for navigation system was considered. An adaptive filtering technique is developed for the system with unknown and varying sway disturbance. It is assumed that the random sway motion is the second order ARMA(Auto Regressive Moving Average) model and performed parameter identification for unknown parameters. Designed adaptive filter contain both a Kalman filter and a self-tuning filter. This filtering system can automatically adapt to varying environmental conditions. To verify the robustness of the filtering system, the computer simulation was performed with unknown and varying sway disturbance.

• 한국정밀공학회지
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• 제31권10호
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• pp.865-871
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• 2014

Paradigm shift to 3-D chip stacking in electronic packaging has induced a lot of integration challenges due to the reduction in wafer thickness and pitch size. This study presents a hybrid bonding technology by self-alignment effect in order to improve the flip chip bonding accuracy with ultra-thin wafer. Optimization of Cu pillar bump formation and evaluation of various factors on self-alignment effect was performed. As a result, highly-improved bonding accuracy of thin wafer with a $50{\mu}m$ of thickness was achieved without solder bridging or bump misalignment by applying reflow process after thermo-compression bonding process. Reflow process caused the inherently-misaligned micro-bump to be aligned due to the interface tension between Si die and solder bump. Control of solder bump volume with respect to the chip dimension was the critical factor for self-alignment effect. This study indicated that bump design for 3D packaging could be tuned for the improvement of micro-bonding quality.

• Journal of Welding and Joining
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• 제27권1호
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• pp.85-89
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• 2009

Reflow process conditions were investigated for 0402 electric parts with Sn-3.0Ag-0.5Cu solders. Circle hole shape metal mask with 100 m thickness showed excellent printability. Self alignment abilities were 71% for 1005 chips, 52% for 0603 chips, and 3% for 0402 chips. Average joining strengos were 1990 gf for 1005 chips, 867 gf for 0603 chips, and 525 gf for 0402 chips. As mis-mounting angle increased, joining strength decreased. Considering self-alignment ability, mounting angle had to be under $5^{\circ}$ and contact area of the chips had to be over 40% for Pb-free soldering process for 0402 chips.

• 한국항공운항학회지
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• 제16권1호
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• pp.29-36
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• 2008

The vulnerability of aircraft, especially rotary wing aircraft, has been an ongoing issue since their advent in combat operations during the 1940s. In this paper, representative sensors for survivability of those aircraft in modern battlefield are surveyed and top level requirements and parameters are defined. Also problems of multi-sensor alignment on modern agile and flexible platform are discussed and several techniques such as static alignment and transfer alignment are introduced.

• Journal of Korean Neurosurgical Society
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• 제61권2호
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• pp.167-179
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• 2018

The prevalence of patients with adult spinal deformity (ASD) has been reported as high as 68%. ASD often leads to significant pain and disability. Recent emphasis has been placed on sagittal plane balance and restoring normal sagittal alignment with regards to the three dimensional deformity of ASD. Optimal sagittal alignment has been known to increase spinal biomechanical efficiency, reduce energy expenditure by maintaining a stable posture with improved load absorption, influence better bony union, and help to decelerate adjacent segment deterioration. Increasingly positive sagittal imbalance has been shown to correlate with poor functional outcome and poor self-image along with poor psychological function. Compensatory mechanisms attempt to maintain sagittal balance through pelvic rotation, alterations in lumbar lordosis as well as knee and ankle flexion at the cost of increased energy expenditure. Restoring normal spinopelvic alignment is paramount to the treatment of complex spinal deformity with sagittal imbalance. Posterior osteotomies including posterior column osteotomies, pedicle subtraction osteotomies, and posterior vertebral column resection, as well anterior column support are well known to improve sagittal alignment. Understanding of whole spinal alignment and dynamics of spinopelvic alignment is essential to restore sagittal balance while minimizing the risk of developing sagittal decompensation after surgical intervention.

• 융합정보논문지
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• 제9권8호
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• pp.243-247
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• 2019

본 연구는 6주간 20대의 일반 대학생을 대상으로 척추 정렬과 균형능력에 대한 클라이밍 운동 프로그램이 자기효능감에 미치는 영향에 대해 알아보았으며, 실험대상자는 총 30명이었으며, 6주간 주 3회 씩 상지와 하지에 대한 클라이밍 운동프로그램을 실시하였고, 결과는 다음과 같았다. 자기효능감의 군내 비교에서는 훈련군에서 유의한 차이가 있었다. 따라서, 클라이밍 운동이 자기효능감에 정상성인의 동기부여를 향상하는데 영향을 줄 수 있다는 것을 알 수 있었다. 결론적으로 추후 다양한 실험자들에게 클라이밍 운동을 실시할 시 참고 자료로 사용될 수 있을 것이라 사료된다.

• Journal of Information Display
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• 제11권4호
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• pp.144-148
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• 2010

In this paper, vertically aligned (VA) liquid crystal (LC) modes were investigated using the alkyl chain ordering effect of self-assembled monolayers (SAMs) prepared on the anisotropic inorganic surface. On the anisotropic surface prepared through oblique ion beam irradiations, the SAM molecules are adsorbed, producing macroscopic alkyl chain ordering, which can determine the pretilt direction of the vertically aligned LC molecules through the intermolecular interactions on the surface.