• 대한족부족관절학회지
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• 제11권2호
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• pp.226-231
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• 2007

Purpose: To evaluate the clinical outcomes and radiographic results of open reduction and internal fixation for intraarticular calcaneal fractures. Materials and Methods: We reviewed 20 cases of calcaneal fractures managed with open reduction and internal fixation from March 2003 to January 2005. We used the computed tomographic classification system proposed by Sanders et al to classify these fractures. Preoperative and postoperative Bohler's angle, heel height (calcaneal facet height) and calcaneal length, calcaneal width were measured. The Creighton-Nebraska Health Foundation Assessment score was used for clinical evaluation. Results: There were 12 cases of type II fractures, 5 of type III fractures and 3 of type IV fractures. The mean clinical score was 84.3 for type II, 82.6 for type III and 56.1 for type IV. The mean preoperative $B{\ddot{o}}hler$ angle was $6.1^{\circ}$ and final was $22.8^{\circ}$. The mean preoperative calcaneal facet height was 76.6 mm and final was 80.3 mm (The mean calcaneal facet height was changed from preop 76.6 mm to postop 80.3 mm). The mean preoperative calcaneal length was 88.2 mm and final was 92.6 mm. The mean preoperative width was 38.1 mm and final was 35.6 mm. Conclusion: Open reduction and internal fixation showed good results for type II and III fractures, but for type IV fractures the clinical result was significantly worse than the other types. However, type IV fractures still had restoration of (should be restored in) $B{\ddot{o}}hler's$ angle, calcaneal facet height, calcaneal length and width which may be helpful in later subtalar fusion.

• Clinics in Shoulder and Elbow
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• 제26권1호
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• pp.41-48
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• 2023

Background: Shoulder instability procedures have low morbidity; however, complications can arise that result in readmission to an inpatient healthcare facility. The purpose of this study is to identify the demographics and risk factors associated with unplanned 30-day readmission and reoperation following arthroscopic and open treatment for shoulder instability. Methods: The American College of Surgeons National Surgical Quality Improvement Program database was queried to find patients who underwent shoulder instability surgery from 2015 to 2019. Independent sample Student t-tests, chi-square, and (where appropriate) Fisher's exact tests were used in univariate analyses to identify demographic, lifestyle, and perioperative variables related to 30-day readmission and reoperation following repair for shoulder instability. Multivariate logistic regression modeling was subsequently performed. Results: Of the 11,230 cases included in our sample, only 0.54% were readmitted, and 0.23% underwent reoperation within the 30-day postoperative period. Multivariate logistic regression modeling confirmed that the following patient variables were associated with statistically significantly increased odds of readmission and reoperation: open repair, congestive heart failure (CHF), and hospital length of stay. Conclusions: Unplanned 30-day readmission and reoperation after shoulder instability surgery is infrequent. Patients with American Society of Anesthesiologists class II, CHF, longer than average hospital length of stay, or an open procedure have higher odds of readmission than patients without those factors. Patients who have CHF, longer than average hospital length of stay, and open surgery have higher odds of reoperation than others. Arthroscopic procedures should be used to manage shoulder instability, if possible. Level of evidence: III.

• 대한전자공학회논문지
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• 제19권6호
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• pp.80-83
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• 1982

X-밴드 주파수에서 λg/4 개방 마이크로스트립 선로 급전형 스로트 점렬을 구현하였다. 최적 급전점은 실험적으로 결정하였고 스로트 점각의 여러 주파수에서 입력 임피던스와 복재 패턴을 측정하였으며 다소 다른 길이의 16개 소자와 본 논문에서 제시한 급전 선로를 사용하여 주파수 대역을 증가시켜 보았다. A quarter-wavelength open circuited microstripline slot array is realized at X-band froquency. The optimal feeding point is experimentally determined. The input impedance of the slot array for various frequencies and its radiation pattern are measured. The bandwidth of the slot array is increased by using the 4×4 elements which are slightly different in length and feeding network which is suggested in this papers.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.85-101
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• 2020

The optimal parameters for the fluid-structure interaction analysis using the Smoothed Particle Hydrodynamics (SPH) for fluids and finite elements for structures, respectively, are explored, and the effectiveness of the simulations with those parameters is validated by solving several open surface fluid problems. For the optimization of the Equation of State (EOS) and the simulation parameters such as the time step, initial particle spacing, and smoothing length factor, a dam-break problem and deflection of an elastic plate is selected, and the least squares analysis is performed on the simulation results. With the optimal values of the pivotal parameters, the accuracy of the simulation is validated by calculating the exerted force on a moving solid column in the open surface fluid. Overall, the SPH-FEM coupled simulation is very effective to calculate the fluid-structure interaction. However, the relevant parameters should be carefully selected to obtain accurate results.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2021년도 학술발표회
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• pp.60-60
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• 2021

Investigating Backward-Facing Step(BFS) flow is important in that it is a representative case for separation flows in various engineering flow systems. There have been a wide range of experimental, theoretical, and numerical studies to investigate the flow characteristics over BFS, such as flow separation, reattachment length and recirculation zone. However, most of such previous studies were concentrated only on the perpendicular step angle. In this study, several numerical investigations on the flow pattern over BFS with various step angles (10° ~ 90°) and expansion ratios (1.48, 2 and 3.27) under different Reynolds numbers (5000 ~ 64000) were carried out, mainly focused on the reattachment length. The numerical simulations were performed using an open source 3D CFD software, OpenFOAM, in which the velocity profiles and turbulence intensities are calculated by RANS (Reynolds Averaged Navier-Stokes equation) and 3D LES (Large Eddy Simulation) turbulence models. Overall, it shows a good agreement between simulations and the experimental data by Ruck and Makiola (1993). In comparison with the results obtained from RANS and 3D LES, it was shown that 3D LES model can capture much better and more details on the velocity profiles, turbulence intensities, and reattachment length behind the step for relatively low Reynolds number(Re < 11000) cases. However, the simulation results by both of RANS and 3D LES showed very good agreement with the experimental data for the high Reynolds number cases(Re > 11000). For Re > 11000, the reattachment length is no longer dependent on the Reynolds number, and it tends to be nearly constant for the step angles larger than 30°.) Based on the calibrated and validated numerical simulations, several additional numerical simulations were also conducted with higher Reynolds number and another expansion ratio which were not considered in the experiments by Ruck and Makiola (1993).

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2002년도 학술대회 논문집
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• pp.193-196
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• 2002

The thermoacoustic refrigerator has not only considerable possibility but also commercial usability, because it has high reliability, lower vibration, no moving part, and can easily be constructed. In order to determine the optimum resonant tube length and the frequency, the open-tube-type(3$\lambda$/4) and close- tube - type (2$\lambda$/2) thermoacoustic refrigerator were constructed. In third harmonic, the temperature difference of 3$\lambda$/4 refrigerator was $53^{\circ}C$(resonator length :400mm). In second harmonic, the temperature difference of 2$\lambda$/2 refrigerator was $51^{\circ}C$(resonator length :400mm).

• 대한치과교정학회지
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• 제15권2호
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• pp.249-259
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• 1985

To analyze the skeletal characteristics of the open bite, the faces of normal occlusion and open bite were measured using a cephalogram. The factors which were greatly different from normal occlusion were selected. The effects of these factors on the incisal overbite and correlation on these factors were studied. The following results were obtained: 1. The 13 factors which comprised the characteristics of the open bite were obtained. (Table 5) 2. The cause and amount of the open bite were dependent on the skeletal angulation than skeletal length. 3. For determining the incisal overbite, most highly correlated single factor was the interincisal angle. 4. The correlation on the selected 13 factors which comprised the characteristics of the open bite was obtained. (Table 6) 5. The open bite was due to combination of various factors than due to single factor. (Table 3,4).

• 대한치과교정학회지
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• 제25권6호
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• pp.665-674
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• 1995

The purpose of this study is to investigate the cephalometric characteristics of the open-bite patients with DJD of TMJ. The DJD open-bite cases were compared with normal samples and Class II open-bite cases with normal TMJ respectively. Twenty three open-bite patients with bilateral DJD of TMJ($13.9\~35.3$ yens old, Group I) were selected from the Department of Orthodontics, SNUDH. Group ll consisted of thirteen Class II open-bite cases($13.2\~27.4$ years old) with no TMD signs/symtoms and good condylar shapes. Group III samples were the forty eight healthy dental students who have Class I molar relationships with no history of orthodontic treatment, good facial balance and no TMD symptoms($20.0\~26.8$ years old). First, sixty measurements in the lateral cephalometric radiographs and analysis of variance(P<0.05, Scheffe) were used to compare these three groups. The seven measurements showed significant difference(p<0.05) between Group I and Group II. After analysis of variance, six of them were used for the discriminant analysis(Wilks' stepwise analysis) and the discrminant function for Group I/Group II was obtained. The results and conclusions were as follows : In most of the measurments, Group I and Group II showed the same skeletal and dental characteristics. But seven of the sixty measurements(FH-PP angle, SNB, FH-ArGo angle, articulare angle, genial angle, upper gonial angle and Ar-Go length) were significantly different(p<0.05) between Group I and Group II. These differences may be explained by the fact that in DJD cases the mandible rotated backward due to the shortening of the ramus following the degenerative destruction of condylar head and its surrounding structures. The resulting discriminant function was : $D={-0.120X}_1+{0.066X}_2+{0.144X}_3-{0.058X}_4+2000,\;where\;X_1=ArGo\;length(mm),\;X_2=SArGo\;angle(degree),\;X_3=FH-PP\;angle(degree),\;X_4=Gonial\;angle(degree)$. Mean of the group centroids was -0.555 and percent of the 'grouped' cases correctly classified was $88.89\%$.

• 한국전자파학회논문지
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• 제18권8호
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• pp.854-861
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• 2007

본 논문에서는 radar detector에 사용 가능한 국부 발진단용 소형화된 L 모양 shorted pin patch를 제안하였다. Shorted pin patch는 일반적인 구형 patch가 가지는 open-open 공진 형태가 아닌 short-open 공진 형태를 가지고 작동한다. L모양의 shorted pin 배열은 기본 모드(X-band), $2^{nd}\;and\;3^{rd}$ 모드에서 ${\lambda}/4$ 및 $3{\lambda}/4$의 공진 구조를 가지게 되어 일반적인 구정 patch보다 소형화가 가능하다 최적화된 L 모양 소정 shorted pin patch는 국부 발진단의 발진 주파수 대역(X, K and Ka band)에서 공진이 일어나 향상된 반사 손실을 가지게 되고, 이에 따라 기존 대비 향상된 radar detector의 감도는 얻을 수 있을 것으로 예상된다.

• 한국세라믹학회지
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• 제34권11호
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• pp.1139-1150
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• 1997

A model for predicting the relative density and the compressive strength of open-cell ceramics with three-dimensional network structure was proposed through the interpretation of their macrostructure and fracture mechanics. The equation predicting the relative density was derived under the assumption that the open-cell structure was a periodic array of the tetrakaidecahedron unit cell consisting of cylindrical struts containing the internal hollow with the shape of a triangular prism. The model for compressive strength of open-cell ceramics with the hollow strut was also developed by modifying conventional model which based on fracture behavior of them subjected to the compressive stress. Both the relative density and the compressive strength were expressed in terms of the ratio of the strut diameter to the length together with the ratio of the hollow size to the strut diameter. The proposed model for the relative density and the compressive strength of the alumina-zirconia composite with open-cell structure were accorded well with the experimental values, whereas Gibson-Ashby and Zhang's model did not show such a good agreement.