• Journal of Biomedical Engineering Research
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• v.24 no.5
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• pp.447-451
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• 2003

A new method for analyzing the bone-remodeling process using quasi-molecular dynamics was proposed in this study. The effect of pressure due to bone marrow, which could not be considered in previous methods, was also considered in this method. Bone-remodeling response of the 2D vertebral body of lumbar spine to a uniaxial compressive displacement of 1.8564mm. corresponding to approximately 2kN of compressive load, was studied. Converged shape change of the cortical shell and rearrangement of cancellous bone structure matched well with a normal shape of the vertebral body. The calculated responses in the spinal elements also shows closed results compared with experimental results.

• The Korean Journal of Rheology
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• v.3 no.2
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• pp.166-174
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• 1991

동일화학종이면서 \ulcorner량이 다른 두 단분산 고분자를 혼합한 2성분 다분산 농축계에 equivalent primitive chain model을 적용하여 사슬주위의 제약완화에 따른 관의 재형성 효 과를 각 사슬의 특성완화시간으로 산정하여 나타내었다. Polystyrene 시료에 대하여 동력하 적 실험을 실시한 결과를 이용하여 사동모델에 따른 각 사슬의 최장완화시간은 복소수 점도 의 허수분분(η＂)대 주파수($\omega$)의 관계, 관의 재형성 시간은 $\omega$ 변화에 따른 storage modulus(G＇) 로부터 각각 도출하였다. 이러한 작업을 통하여 특성완화 시간들이 분자량 및 각 성분 농도에의 의존성을 더욱 상세히 파악할 수 있었다.

• Journal of Yeungnam Medical Science
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• v.20 no.1
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• pp.28-35
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• 2003

Purpose: To evaluate physeal remodeling after internal fixation of slipped capital femoral epiphysis, We performed a retrospective review of the medical records and radiographs of 14 children (17 cases) who had had slipped capital femoral epiphysis. Materials and Methods: We reviewed 14 patients who had slipped capital femoral epiphysis. They were divided two groups. Group I were in situ pinning with single screw and group II were corrective osteotomy with multiple pinning. We identified physeal remodeling camparing with their preoperative, postoperative and last follow-up radiographs with measuring physeal-shaft angle. Results: Early closure of the physis was observed in 6 cases among 14 patients (17 hips). Compared with their postoperative radiographs, the last follow up radiographic study revealed that physeal remodeling was observed in 4 patients (4 hips) at group I (mean, $7.8^{\circ}$), in 2 patients (3 hips) at group II (mean, $10.7^{\circ}$). Conclusion: In this study, physeal remodeling was observed in 4 patients (4 hips) in group I and 2 patients (3 hips) in group II. The incidence of physeal remodeling was related with degree of epiphyseal slippage, and age was not related with physeal remodeling potential.

• Journal of Chest Surgery
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• v.30 no.6
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• pp.559-565
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• 1997

Donor airway ischemia is a significant problem after tracheal replacement with homograft or lung transplantation, Several factors such as omentopexy, heparin, PGl2 and fibroblast growth factor, have been shown to induce angiogenesis in vitro and in vivo. This study was designed to investigate whether omentopexy and basic flbroblast growth factor can enhance rabbit tracheal revascularization and epithelial regeneration, Three different experiments were performed with New Zealand white rabbit. In group I(n= 15 control group), only coNical tracheal autotransplantation was done. In group II(n= 15), cervical tracheal autotransplantation with omentopexy was done through subcutaneous route. In group III(n= 15), cervical tracheal autotransplantation was done and lug basic flbroblast growth factor was applied. After 3, 7 and 14 days, the animals were sacrificed. The extent of revascularization was investigated by means of uptake of the human serum albumin labelled with 99m technetium, and epithelial regeneration were assessed by means of light microscope. In the group investigated at day 3, there was statistically significant high tracheal revascularization in group III(p<0.05), but no difference at 7 and 14 days. And epithelial regenerations at day 3 were better in group III(p<0.05), and at day 7 in group II and III. But there was no difference at day 14. We concluded that b-FGF can enhance the revascularization and epithelial regeneration of the tracheal autograft especially in early phase.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2005.11a
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• pp.137-140
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• 2005

Alum과 PDDA에 대하여 각각 휴믹산의 플럭 형성-파괴-재형성을 관찰 한 결과 sweep flocculation에 의해 휴믹 플럭을 형성하는 alum은 플럭의 파괴 및 재형성은 비가역적이이나 유기응집제인 PDDA 플럭의 파괴는 가역적이라는 것을 알 수 있었다. 그리고 플럭 강도지수 측정으로부터 PDDA는 alum보다 높은 강도를 가지는 것을 알 수 있었다. 그리고 플럭강도에 미치는 이온강도의 영향을 살펴 보면 alum은 플록강도에 미치는 영향이 거의 없었지만 유기응집제인 PDDA는 플럭 강도가 크게 감소함을 알 수 있었다.

• Journal of KIISE:Information Networking
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• v.32 no.1
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• pp.110-122
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• 2005

Bluetooth has been reputed as a wireless networking technology supplying ad-hoc networks between digital devices. In particular, bluetooth scatternet is a most essential part for dynamic ad-hoc networks. But past researches on bluetooth scatternet has hardly treated dynamic scatternet environment. In this paper, we proposed a scatternet reformation algorithm for the case that some nodes escape from the scatternet. The proposed algorithm is a general algorithm which can be applied to many types of bluetooth scatternet regardless of the topology. The proposed algorithm has short reformation time delay because the process has only page process (not including inquiry process ). The algorithm is operated based on Recovery Node Vector which is composed of Recovery Master and Recovery Slave. In this paper, we performed the real hardware experiments for evaluating the performance of the proposed algorithm. In that experiments, we measured the reformation time and reformation probability. In comparison with the case including inquiry process, the proposed algorithm had the improvement in reformation time delay and we obtained high success rate over 97%.

• Journal of the Korean Orthopaedic Association
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• v.56 no.1
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• pp.82-86
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• 2021

A traumatic sternal segment dislocation in children is very rare. Of the few cases reported, some recommended surgical treatment, while others reported good results by conservative treatment. Therefore, the treatment remains unclear. This paper reports a case of completely remodeled traumatic sternal segment dislocation in a 13-year-old boy treated by the restriction of activity and periodic observations.

• The korean journal of orthodontics
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• v.38 no.5
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• pp.347-357
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• 2008

Objective: The purpose of this study was to examine the effect of ipriflavone on periodontal reorganization and prevention of relapse following tooth movement. Methods: Orthodontic rubber bands were inserted between the first and second maxillary molars of 27 white male rats for 3 weeks for experimental tooth movement. From one day before the removal of orthodontic rubber band, ipriflavone was administered 50 or 400 mg/kg daily in each experimental group whereas carboxymethyl cellulose solution was administered in the control group. They were sacrificed at the 5, 10, and 15th day from the day of removal of orthodontic rubber bands. The amount of relapse was evaluated by measuring the interdental space, and the extent of periodontal reorganization was compared through histological examination. Results: In case of ipriflavone administration, the amount and velocity of relapse was less and slower compared to the control group. In addition, the ipriflavone group showed more rapid periodontal reorganization compared to the control group. Conclusions: The results of the present study suggest that ipriflavone administration can be used effectively in the prevention of relapse following orthodontic tooth movement through the acceleration of periodontal reorganization.

• The Journal of the Acoustical Society of Korea
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• v.33 no.2
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• pp.118-125
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• 2014

An approximation of speed of sound in the measurement plane is essential for the inverse estimation of temperature. To this end, an inverse problem relating the measured retarded time data in between set of sensors and actuators array located on the wall is formulated. The involved transfer matrix and its coefficient vectors approximate speed of sound of the measurement plane by using the radial basis function with finite number of interpolation points deployed inside the target field. Then, the temperature field can be reconstructed by using spatial interpolation technique, which can achieve high spatial resolution with proper number of interpolation points. A large number of retarded time data of acoustic paths in between sensors and arrays are needed to obtain accurate reconstruction result. However, the shortage of interpolation points due to practical limitations can cause the decrease of spatial resolution and deterioration of the reconstruction result. In this works, a regeneration for obtaining the additional retarded time data for an arbitrary acoustic path is suggested to overcome the shortage of interpolation points. By applying the regeneration technique, many interpolation points can be deployed inside the field by increasing the number of retarded time data. As a simulation example, two rectangular duct sections having arbitrary temperature distribution are reconstructed by two different data set: measured data only, combination of measured and regenerated data. The result shows a decrease in reconstruction error by 15 % by combining the original and regenerated retarded time data.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.11
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• pp.821-827
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• 2018

In devices used for re-forming osteoblasts to treat osteoporosis, a magnetic field is applied from the outside of the bone, and the minerals contained in the bone are aligned in a certain direction and undergo precessional motion. When a $90^{\circ}$ RF pulse is applied by using an RF coil, protons of minerals are brought to an excited state, and phosphorus activity promoting the deposition of osteoblasts in the bone is increased, thereby reshaping the bone. Miniaturizing the RF coil that generates a signal corresponding to the harmonic of the precessional motional frequency by means of the $90^{\circ}$ RF pulse can drastically reduce the overall size of the bone reshaping system. In this study, we propose a methodology for the miniaturization of the RF coil that can be used for osteoblast re-formation using a bone reshaping system. The capacitance of the designed RF coil is 25 pF, the inductance is approximately 100 nH, and the resonance frequency is 96 MHz. The radius of the end ring of the designed RF coil is 18 cm, and the total length of the leg is $2{\times}11.6cm$. The performance of the coil is verified through post-design measurement.