• 비파괴검사학회지
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• 제30권2호
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• pp.132-138
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• 2010

본 연구에서는 접촉역학 특성에 의한 캔틸레버 탑의 접촉-진동을 연구하고 나노스케일의 표면에서 탄성특성을 이미지화 하였다. 스프링-질량 모텔과 Herzian 이론을 이용하여 접촉공진주파수를 이론적으로 계산하고 초음파원자현미경을 이용하여 캔틸레버의 자유공진주파수와 접촉공진주파수의 변화를 분석하였다. 또한, 프로토타입의 초음파원자현미경을 이용하여 구상화 열처리된 시험편의 탄성 이미지를 위상과 진폭 신호를 이용하여 성공적으로 얻을 수 었었다.

• Current Optics and Photonics
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• 제6권1호
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• pp.69-78
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• 2022

A high-resolution camera is a precise optical system. Its vibrations during transportation and launch, together with changes in temperature and gravity field in orbit, lead to different degrees of defocus of the camera. Thermal refocusing is one of the solutions to the problems related to in-orbit defocusing, but there are few relevant thermal refocusing mathematical models for systematic analysis and research. Therefore, to further research thermal refocusing systems by using the development of a high-resolution micro-nano satellite (CX6-02) super-resolution camera as an example, we established a thermal refocusing mathematical model based on the thermal elasticity theory on the basis of the secondary mirror position. The detailed design of the thermal refocusing system was carried out under the guidance of the mathematical model. Through optical-mechanical-thermal integration analysis and Zernike polynomial calculation, we found that the data error obtained was about 1%, and deformation in the secondary mirror surface conformed to the optical index, indicating the accuracy and reliability of the thermal refocusing mathematical model. In the final ground test, the thermal vacuum experimental verification data and in-orbit imaging results showed that the thermal refocusing system is consistent with the experimental data, and the performance is stable, which provides theoretical and technical support for the future development of a thermal refocusing space camera.

• 대한영상의학회지
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• 제84권3호
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• pp.770-775
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• 2023

악성 말초 신경 초종은 드문 연부조직 종양으로, 주로 몸통, 사지, 두경부에 주로 위치하며, 유방에는 드물다. 저자들은 신경섬유종증 1을 가진 27세 여자 환자에서 유방으로 전이된 악성 말초 신경 초종 증례를 보고하고자 한다. 흉부 단층촬영에서 오른쪽 유방에 경계가 분명한 타원형의 약간 조영 증강되는 종괴가 보였다. 초음파에서 혈류와 증등도의 탄성을 가진 경계가 분명한 타원형의 비균질한 에코의 종괴로 보였다. 유방 종괴는 수술로 제거되었고, 악성 말초 신경 초종으로 최종 진단되었다. 드물지만, 악성 말초 신경 초종은 신경섬유종증 1을 가진 환자에서 유방 종괴의 감별진단에 포함되어야 한다.

• Asian Pacific Journal of Cancer Prevention
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• 제14권2호
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• pp.935-940
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• 2013

Background: To evaluate the diagnostic utility of conventional ultrasonography and real time ultrasound elastography in differentiating degenerating cystic thyroid nodules mimicking malignancy from papillary thyroid carcinoma. Methods: We retrospectively analyzed conventional ultrasonographic and elastographic characteristics of 19 degenerating cystic thyroid nodules mimicking malignancy in 19 patients, with 30 surgically confirmed PTCs as controls. Based on size, the nodules had been grouped into less than 10mm (group A) and greater than 10 mm (group B). We evaluated conventional parameters and elasticity pattern. Color-scaled elastograms were graded as to stiffness of nodules using an elasticity pattern from I (soft) to IV (stiff). Results: Degenerating cystic thyroid nodules were similar to PTCs in conventional ultrasonographic findings, but the former frequently showed oval to round in shape (group A, 69.2% vs 18.8%, P=0.017; group B, 66.7% vs 7.14%, P=0.017) and punctuate hyperechoic foci (group A, 61.5% vs 0, P<0.001; group B, 50% vs 0, P<0.001). On real time ultrasound elastography, 7 of 13 degenerating cystic thyroid nodules in group A were pattern I, 5 were pattern II, 1 was pattern III. One degenerating cystic thyroid nodule in group B was pattern II, 5 were pattern III. The area under the curve for elastography was 0.98 in group A (sensitivity 92.3%, specificity 100%, P = 0.002), and 0.88 in group B (sensitivity 16.7%, specificity 100%, P = 0.014). Conclusions: As a dependable imaging technique, elastography helps increase the performance in differential diagnosis of degenerating cystic thyroid nodule and malignancy.

• 한국방사선학회논문지
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• 제12권2호
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• pp.217-223
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• 2018

본 연구는 유방종괴에서 횡탄성 초음파검사(SWE)의 진단 수행도를 알아보고, 조직검사 결과와 SWE에서 얻어지는 강성도와 비교하고자 하였다. 진단적 유방 초음파와 SWE를 2017년 6월부터 2017년 9월까지 유방 초음파 검사 상 종괴가 발견된 환자 157명을 대상으로 하였다. 157명의 병리학적 결과는 양성 92명(나이, $44.54{\pm}11.84$), 악성 65명(나이, $51.55{\pm}10.54$)으로 나타났다. 진단적 유방 초음파의 유방영상보고데이터체계(BI-RADS)에 따른 최종 평가, 조직검사 결과, 정량적 SWE 결과를 구하고 서로 비교하였다. 정량적 SWE 수치와 병리학적 결과에서 진단 특이도는 평균탄성값(Emean)에서 83.70%로 가장 높게 나왔으며, 민감도는 최소탄성값(Emin)에서 89.23%로 가장 높게 나타났다. 정량적 SWE값과 조직검사결과와는 통계학적으로 유의한 차이를 나타내었다.(p=0.000) 악성병변에서 최적의 절사값(cut-off value)은 민감도, 특이도가 높은 최대탄성값(Emax), 평균탄성값(Emean)에서 66.3 kPa, 63.7 kPa로 나타났으며 이는 다른 SWE 측정 수치들과 비교했을 때 가장 높은 진단 곡선 하 면적(area under the curve; AUC)값을 보였다.(p=0.000) 유방종괴에서 기존의 초음파에서 SWE를 추가적으로 시행하는 것은 진단 특이도를 높이고 불필요한 조직검사를 줄일 수 있다. 따라서 상기 분석법 및 기기를 이용하여 유방종괴를 분석하는 데에 도움을 받을 수 있게 될 것으로 기대한다.

• Journal of Acupuncture Research
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• 제29권2호
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• pp.43-57
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• 2012

Objectives : The purpose of this study is to observe the effects of $Sa-Am$ lung sedating acupuncture (LS) on wrist pulse changes in healthy participants. Method : Forty healthy subjects participated in this study, and were divided into an acupuncture group and controlled group. Using a three-dimensional pulse imaging system (DMP-3000), wrist pulse was measured before, immediately after, 30 minutes after and 60 minutes after acupuncture in the acupuncture group, with the rest in controlled group. Sixteen parameters between the acupuncture group and the controlled group were analyzed at Cun, Guan and Chi in each time. Result : After LS acupuncture, wrist pulse sixteen parameters were changed significantly according to the time at each measuring region. 1. Heart rate significantly decreased in immediately after, 30 minutes after and 60 minutes after, Pulse period significantly increased in 30 minutes after and 60 minutes after. 2. T4 didn't significantly changed, T-T4 significantly increased in immediately after, 30 minutes after and 60 minutes after. T4/T, T4/(T-T4), T1/T, T5/T significantly decreased in immediately after, 30 minutes after and 60 minutes after. (T-T4)/T significantly decreased in immediately after, 30 minutes after and 60 minutes after. T5 significantly increased in 30 minutes after and 60 minutes after. 3. Modulus of elasticity significantly decreased in left Cun 60 minutes after, significantly increased in left Chi 30 minutes after. 4. Variance of Amplitude significantly increased in right Guan 60 minutes after. 5. Area of pulse significantly increased in left Cun 60 minutes after, left Chi 30 minutes after and right Cun 60 minutes after. Systolic pulse area significantly decreased left Chi 30 minutes after, right Cun immediately after, 30 minutes after and 60 minutes after, right Guan in immediately after. 6. Energy/min significantly decreased in left Chi 60 minutes after and right Cun immediately after. EIx significantly decreased in right Cun immediately after. 7. In both sides Cun, Guan, Chi wrist pulse, a lot of significant changes in right Cun and left Chi appeared, and then followed by the left Cun, right Guan. Conclusion : This study analyzed that the correlation between LS acupuncture and radial pulse(cun, guan, chi) is considered to be meaningful, hereafter clinical studies on this are needed.

• 한국운동역학회지
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• 제25권2호
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• pp.175-182
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• 2015

Objective : The purpose of this study was to investigate difference in fascicle behavior of the medial gastrocnemius during the locomotion with varying intensities, such as gait and one-legged and two-legged vertical jumping. Methods : Six subjects (3 males and 3 females; age: $27.2{\pm}1.6yrs.$, body mass: $62.8{\pm}9.8kg$, height: $169.6{\pm}8.5cm$) performed normal gait (G) at preferred speed and maximum vertical jumping with one (OJ) and two (TJ) legs. While subjects were performing the given tasks, the hip, knee and ankle joint motion and ground reaction force was monitored using a 8-infrared camera motion analysis system with two forceplates. Simultaneously, electromyography of the triceps surae muscles, and the fascicle length of the medial gastrocnemius were recorded using a real-time ultrasound imaging machine. Results : Comparing to gait, the kinematic and kinetic parameters of TJ and OJ were found to be significantly different. Along with those parameters, change in the medial gastrocnemius (MG) muscle-tendon complex (MTC) length ($50.57{\pm}6.20mm$ for TJ and $44.14{\pm}5.39mm$ for OJ) and changes in the fascicle length of the MG ($18.97{\pm}3.58mm$ for TJ and $20.31{\pm}4.59mm$ for OJ) were observed. Although the total excursion of the MTC and the MG fascicle length during the two types of jump were not significantly different, however the pattern of length changes were found to be different. For TJ, the fascicle length maintained isometric longer during the propulsive phase than OJ. Conclusion : One-legged and two-legged vertical jumping use different muscle-tendon interaction strategies.

• 한국운동역학회지
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• 제24권1호
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• pp.35-42
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• 2014

Tendon elasticity is an important factor affecting muscle function and thus human movements. It has been reported that the mechanical properties of tendon are adaptable to external loading condition. Based on the adaptability of muscle and tendon to external loading conditions, one can assume that there might be an optimum ratio between muscle strength and tendon stiffness. The present study aimed to investigate whether there is correlation between plantar flexor muscle strength and stiffness of the achilles tendon (AT). Twenty two male subjects (age: $23.2{\pm}1.5yrs$, height: $175.5{\pm}6.2cm$, weight: $75.4{\pm}9.8kg$) performed maximum voluntary isometric plantarflexion on a custom-built dynamometer and muscle-tendon junction of the medial gastrocnemius muscle was simultaneously monitored using a real-time ultrasound imaging machine. The averages of muscle force and tendon stiffness were $366.38{\pm}79.37N$, $35.34{\pm}10.42N/mm$, respectively. Significant positive correlation was observed between muscle strength and tendon stiffness (r=0.8507), indicating that the muscle force is proportional to tendon stiffness. The results might have been used in computational modeling and criterion of training progress level in the fields of training and rehabilitation.

• Journal of Acupuncture Research
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• 제29권5호
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• pp.17-29
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• 2012

Objectives : The purpose of this study is to find the effects of Sa-Am lung tonifying acupuncture on radial pulse through the parameters difference. Methods : Forty healthy subjects participated in this study, acupuncture group and control group were divided. Compared various parameters of radial pulse between two groups, and the significantly changed 16 parameters ware measured using 3 dimensional pulse imaging system(DMP-3000) before, right after, 30 minutes after, and 60 minutes after acupuncture at Chon, Gwan, Cheok in acupucture group. Results : After lung tonifying acupuncture, radial pulse 16 parameters were showed changes significantly according to the time at each measuring location. 1. Heart rate, T2/T, T5, T5/T and W/T significantly decreased, W significantly increased. 2. Modulus of elasticity significantly decreased in left Cheok. 3. Amplitude of H4 significantly increased in left Gwan and right Cheok. 4. AIx, AIxHR significantly decreased in left Gwan and significantly increased in right Chon. 5. Area of pulse, area of W significantly increased in right Cheok. 6. Pulse energy, energy/min, EIx significantly decreased in left Cheok. 7. Maximum variation time of each parameter is showed different according to the parameter. Conclusions : Lung tonifying acupuncture exerts an influence on radial purse parameters. Further radial pulse change study on various acupuncture treatment is required.

• The Journal of Advanced Prosthodontics
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• 제16권2호
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• pp.91-104
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• 2024

PURPOSE. The objectives of the current study were to estimate the influence of self-reinforced hollow structures with a graded density on the dimensional accuracy, weight, and mechanical properties of Co-Cr objects printed with the direct metal laser sintering (DMLS) technique. MATERIALS AND METHODS. Sixty-five dog-bone samples were manufactured to evaluate the dimensional accuracy of printing, weight, and tensile properties of DMLS printed Co-Cr. They were divided into Group 1 (control) (n = 5), Group 2, 3, and 4 with incorporated hollow structures based on (spherical, elliptical, and diamond) shapes; they were subdivided into subgroups (n = 5) according to the volumetric reduction (10%, 15%, 20% and 25%). Radiographic imaging and microscopic analysis of the fractographs were conducted to validate the created geometries; the dimensional accuracy, weight, yield tensile strength, and modulus of elasticity were calculated. The data were estimated by one-way ANOVA and Duncan's tests at P < .05. RESULTS. The accuracy test showed an insignificant difference in the x, y, z directions in all printed groups. The weight was significantly reduced proportionally to the reduced volume fraction. The yield strength and elastic modulus of the control group and Group 2 at 10% volume reduction were comparable and significantly higher than the other subgroups. CONCLUSION. The printing accuracy was not affected by the presence or type of the hollow geometry. The weight of Group 2 at 10% reduction was significantly lower than that of the control group. The yield strength and elastic modulus of the Group 2 at a 10% reduction showed means equivalent to the compact objects and were significantly higher than other subgroups.