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러시아의 뉴 다이아몬드 테크놀러지에서 생산된 보석용 합성 다이아몬드의 특성
최현민,김영출,Choi, Hyunmin,Kim, Youngchool 한국결정성장학회 2015 韓國結晶成長學會誌 Vol.25 No.5
러시아 상트페테르부르크에 소재한 뉴 테크놀로지 다이아몬드(NDT)에서 생산된 보석용 합성 다이아몬드의 보석학적, 분광학적 특성을 조사하였다. 컬러(무색은 극미량의 붕소를 함유하고 있고 블루는 미량의 붕소를 함유하고 있음)와 클래리티 등급은 천연 다이아몬드와 비교할 때 손색이 없었다. NDT 합성 다이아몬드는 자외선 단파에서 블루, 오렌지의 형광과 인광 반응이 관찰되었다. PL 분석에서 H3 센터와 NV 센터가 발견되었으며, H3 센터의 intensity는 천연 다이아몬드와 비교할 때 매우 약하게 존재하였다. NDT에서 생산된 합성 다이아몬드의 보석학적, 분광학적 특징들을 통해 천연 다이아몬드와 구분할 수 있다. Gemological and spectroscopic properties of HPHT synthetic diamonds from New Diamond Technology (NDT) company in St. Petersburg (Russia) were examined. Their color (colorless, near-colorless with some boron and Fancy blue with high boron content) and clarity ($VVS-SI_1$) grades were comparable to those of top natural diamonds. NDT synthetic diamonds fluoresced and phosphoresced blue or orange under SWUV light. Photoluminescence spectra revealed H3 center with very small intensity and NV centers. The intensity of H3 in NDT synthetic diamond has very weak in comparison with natural one. Using a combination of gemological and spectroscopic tests, gem-quality synthetic diamonds from NDT can be distinguished from natural diamonds of similar quality.
김영식(Youngsik Kim),길상철(Sangcheol Kil) 대한용접·접합학회 2017 대한용접·접합학회지 Vol.35 No.2
As the Non Destructive Test (NDT) for the welded structure, PT(Penetration Test). MT(Magnetic Test), RT (Radioisotope Test) and UT(Ultrasonic Test) methods are widely used in practice. These NDT methods have been developed toward high efficiency, low cost, real time, and high precise new NDT. For example, RT methods are developed to CT(Computed Tomography)and DR(Digital Radiography), and UT metheds are developed into Phased array, Guide wave, TOFD method. Moreover, the Infrared thermography and Laser ultrasonic technique are newly developed for applying in high temperature objects as the non-contact NDT methods. In this review paper the new high efficiency NDT methods for the welded structure are introduced and the trend of NDT rules applying in welded structure are described.
김명종,성민재,이예슬,김형남,이지상,박성종,김윤희 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.1
A series of p-type polymers, Naphtho[2,1-b:3,4-b′]dithiophene derivatives (NDT), with enforced coplanar structure for effective π- electron delocalization having naphtho[2,1-b:3,4-b′]dithiophene and another acceptor units were successfully synthesized by Stille coupling reaction. The naphtho[2,1-b:3,4-b′]dithiophene unit of the polymer main chain enhances charge carrier mobility by extending π-conjugation length and rigidly enforced coplanar structure. NDT-based polymers investigated their TFT characteristics.
강선주(Sunju Kang),손대락(Derac Son),조창빈(Changbin Joh),이정우(Jungwoo Lee) 한국자기학회 2016 韓國磁氣學會誌 Vol.26 No.4
In this study, we have constructed a measuring system to investigate tensile stress of tendons, which is employed in bridges, by means of the magnetic non-destructive testing (NDT) method. For the twisted 7-strands tendon, we have used Wiedemann effect. An accurrent was applied to the tendon and voltage induced from Search Coil on Tendon (SCT) under applying tensile stress was measured. The measuring system consists of tensile stress applying apparatus up to 2 GPa, and ac current supply to apply current to the tendon directly to magnetize the tendon. We have invested two kinds of tendon which were produced by different companies for testing with constructed measuring system. Voltage induced from SCT was decreased up to 1.5 GPa linearly and two kinds of tendon which were produced by different companies shows similar trends. Thus, Wiedemann effect was also applicable to measure tensile stress of tendon by means of magnetic NDT.
A study of Ultrasonic guided wave NDT Technique based on PEEK rod
Yang Hu,Ma Wenliang,Wang Zhaoba 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.8
The ultrasonic buffer rod used for polymer testing under the high temperature, not only needs high transmission ultrasound characteristic of SNR, but also low acoustic attenuation, high temperature and strong mechanical properties etc are needed. The role PEEK rod plays in this paper is transmitting ultrasonic guided waves and temperature buffer, so the design of PEEK rod is the key. Through the experimental analysis, the SNR with different diameter and length is gave, and the effect on the ultrasonic characteristics of echo signal is also presented, in order to ensure the high SNR. The conclusions provide a theoretical basis for NDT.
뇌성마비 소아에 대한 중추신경계재활치료 및 피내침 병용치료에 관한 연구 - 기능성 적외선 분광법(fNIRS)를 이용한 예비 연구 -
장석주,남연교,김지현,고문정,권범선,임지연,민상연 대한한방소아과학회 2021 대한한방소아과학회지 Vol.35 No.1
Objectives: The purpose of this study is to investigate differences in brain activities when Neurodevelopmental treatment (NDT) is used alone compare to NDT is combined with intradermal acupuncture (IDA) treatment, using functional infrared spectroscopy (fNIRS) Methods: Three children less than 7 year-old with cerebral palsy were participated. On their first visit, only NDT was used. After a week, they were treated with both NDT and IDA. During the treatment, fNIRS was used to measure any changes in their brain activities. Results: In first patient with NDT, oxyhemoglobin level was increased during Standing exercise and Gait training compared to resting state. When the patient was treated with NDT and IDA, oxyhemoglobin level was decreased during Standing exercise and Gait training compared to resting state, and the result was significant (p<0.05). In second patient, oxyhemoglobin level was decreased in Gait training compared to resting state when NDT was used, but the level was increased when NDT and IDA were used in Gait training compared to resting state (p<0.05). In third patient, the difference in oxyhemoglobin levels between Gait training and resting state was significant (p<0.05). Conclusions: Treatment involving both NDT and IDA has more potential to improve brain activities compared to that of NDT alone, and no adverse effect was reported. In order to confirm the finding, larger scale randomized controlled trials are needed.
Hyungtae Lim,Sungwon Hwang,Sungjae Shin,Hyun Myung 제어로봇시스템학회 2020 제어로봇시스템학회 국제학술대회 논문집 Vol.2020 No.10
In this study, a 3D Normal Distributions Transform (NDT)-based pose correction framework for a mobile robot is proposed to prove its robustness under a considerable odometry uncertainty. Our proposed method consists of Extended Kalan Filter based on IMU and wheel odometry to estimate initial pose and NDT that corrects the initial guess via 3D scans. Then, the final pose correction is retrieved with Kalman gain using corrected poses from both EKF and NDT, followed by point cloud accumulation that generates the global map. Before examining our proposed method, quantitative comparisons of NDT over other 3D scan matching algorithms targeted for mobile robot pose correction were conducted. After that, the experiments are conducted for both indoor environments and outdoor environments. As verified experimentally, NDT is a) suitable for real-time pose correction over other 3D-scan matching algorithms b) robust even when loop closing is not available and c) shows better performance than EKF on pose correction under very imprecise raw odometry. Additionally, we analyzed the time-wise performance of NDT during registration over different voxel sizes of a global map.