In compliance with environmental regulations at sea and the introduction of unmanned autonomous ships, electric propulsion ships are garnering significant attention. Induction machines used as propulsion electric motor (PEM) have maintenance advantages, but speed control is very complicated and difficult. One of the most commonly used techniques for speed control is DTC (direct torque control). DTC is simple in the reference frame transformation and the stator flux calculation. Meanwhile, two-level and three-level voltage source inverters (VSI) are predominantly used. The three-level VSI has more flexibility in voltage space vector selection compared to the two-level VSI. In this paper, speed is controlled using the DTC method based on the specifications of the PEM. The speed controller employs a PI controller with anti-windup functionality. In addition, the characteristics of the two-level VSI and three-level VSI are compared under identical conditions. It was confirmed through simulation that proper control of speed and torque has been achieved. In particular, the torque ripple was small and control was possible with a low DC voltage at low speed in the three-level VSI. The study confirmed that the application of DTC, using a three-level VSI, contributes to enhancing the system's response performance.

Commercial operation of KORI Unit 1 ended in 2017, and the final decommissioning plan is currently under approval from the KINS. In order for the dismantling waste to go to the repository, it is judged that the radioactive waste generated during the commercial operation should be treated and disposed in advance. Among these radioactive wastes, spent filters contain various radionuclides. The radiation dose rate from the radiation coming out of the filters ranges from a low dose rate to high dose rate. Therefore, in order to handle the spent filters, a remote processing system is required to reduce the radiation exposure of workers. This paper evaluates the radioactive inventory of filters that are stored in the filter room at the KORI unit #1. For this purpose, a method for predicting the radioactivity of each nuclide in the filter, based on the radiation dose rate, has been described using the MicroShield code, which is a commercial shielding code. The information on the filters in the field has only the creation date, type, size, and surface dose rate. In order to evaluate the radioactivity inventory using such limited data, it is possible to know the nuclide radioactivity ratio in the filter. We took out some of the filters stored on site and measured from using the ISCOS system, a gamma nuclide analyzer. The radioactivity of each nuclide in the filter was inferred by modeling with the MicroShield code, based on the radiation dose rate and the radioactivity value of each nuclide measured in the field.

We successfully synthesize water-dispersible CTAB-capped CdSe@ZnS quantum dots with the crystal size of the CdSe quantum dots controlled from green to orange colors. The quenching effect of Fe(DTC)3 is very efficient to turn off the emission light of quantum dots at four molar ratios of the CdSe quantum dots, that is, the effective covering the surface of quantum dots with Fe(DTC)3. However, the reaction with Fe(DTC)3 for more than 24 h is required to completely realize the quenching effect. The highly quenched quantum dots efficiently detect nitric oxide at nano-molar concentration of 110nM of NO with 34% of recovery of emission light intensity. We suggest that Fe(DTC)3-hybridized CdSe@ZnS quantum dots are an excellent fluorescence resonance energy transfer probe for the detection of nitric oxide in biological systems.

PURPOSES : Hot-mix asphalt(HMA) concretes show a trend of strength increase at low temperature due to binder stiffness increase, but strength decrease below a ceratin low temperature. This is due to the differential thermal contraction(DTC) which is induced by a significant difference in coefficients of thermal contraction between aggregate and asphalt which is coated around the aggregate. This DTC damage is well known to occur in HMA concrete, but is not yet investigated in warm-mix asphalt(WMA) concretes. METHODS : To evaluate DTC damage on WMA in this study, the flexural strength(Sf) of WMA concretes, which were produced at 30~40℃ lower temperature, was evaluated in comparison with that of HMA at -5, -15 and -25℃. RESULTS : Most of WMA and HMA mixtures showed flexural strength increase down to -15℃ and decrease below -15℃. this type of strength reduction below -15℃ can e explained as the effect of differential thermal contraction that is a consequence of the large difference in coefficients of thermal contraction between aggregate and asphalt. the property reduction of WMA is similar the result of previous works dealt with HMA mixtures. CONCLUSIONS : Even though there is some differences by materials used, the WMA concretes showed a significantly lower DTC damage than HMA concrete at low temperature at α=0.05 level.

유전자를 통해 개인의 질병 · 신체적 특징 정보를 분석하는 "유전자 혁명" 시대가 열리고 있다. 최근 유전자 분석 기술의 발전으로 가격과 분석 기간이 급속도로 줄고 있기 때문이다. 인간은 DNA 내 30억 쌍의 염기서열에 유전자를 담고 있는데, 염기서열을 분석하는 컴퓨터 성능이 크게 발전한 덕분이다. 이러한 시대에 맞춰 정부에서도 유전자 검사에 관한 새로운 상품 및 서비스에 맞는 인증, 허가 기준을 위한 산업융합 규제 샌드박스 제도를 실시하게 되었다. 규제 샌드박스는 신산업・ 신기술 분야에서 새로운 제품이나 서비스를 출시할 때 일정 기간 동안 기존 규제를 면제하거나 유예시켜주는 제도이다. 우리나라에서도 이러한 비용 절감이 우리생활에서 쉽게 할 수 있는 유전자검사로 이어졌고 지난 2016년 6월 ‘생명윤리 및 안전에 관한 법률’이 개정되면서 민간 기업이 일반인을 대상으로 한 유전자 분석 서비스, DTC(Direct to Consumer, 소비자 직접 의뢰) 상품시장이 열렸다. 이에 의료 · 제약업체들이 유전자 검사 서비스를 속속 출시, 다양한 유통채널을 통해 판매하고 있는 모습이다. 이에 국내에 제공되고 있는 개인 유전자 DTC 검사 키트 상품을 경험디자인적 관점에서 분석하여 검사 신청에서 실질적인 검체 채취와 반송에 이르기 까지 가장 적합한 유전자검사 키트 상품 제안은 의미가 크다고 하겠다. 사용자의 경험을 기반으로 한 유전자검사 키트 상품 개발은 앞으로 효율적이고 대중적인 개인 유전자 검사보급에 기초 적 자료 활용이 가능할 것이며 새로운 의료 문화형성과 국민보건의료 향상에 도움을 줄 것으로 기대한다.