• Journal of Sensor Science and Technology
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• v.5 no.2
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• pp.55-60
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• 1996

The growth and microwave plasma assisted nitrogen doping of ZnSe by low pressure organometallic vapor phase epitaxy(OMVPE) has been investigated in a vertical downflow reactor equipped with a laser interferometer for in-situ growth rate measurements. Particular emphasis is placed on understanding growth characteristics of $H_{2}Se$ and the new adduct source dimethylzinc:triethyllamine($DMZn:NEt_{3}$) as compared with those obtained with $H_{2}Se$ and DMZn. At lower temperatures ($<300^{\circ}C$) and pressures(<30Torr), growth rates are higher with the adduct source and the surface morphology is improved relative to films synthesized with DMZn. Hall measurements and photoluminescence spectra of the grown films demonstrate that DMZn and $DMZn:NEt_{3}$ produce material with comparable electronic and optical properties. Microwave plasma decomposition of ammonia is investigated as a possible approach to increasing nitrogen incorporation in ZnSe and photoluminescence spectra are compared to those realized with conventional ammonia doping.

• International journal of advanced smart convergence
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• v.8 no.4
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• pp.40-46
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• 2019

The current education is becoming more extensive with the application of various teaching methods. This is a problem that is so distributed that it is difficult for users to find the data and it takes a long time to find the information they need. Currently, various educational services, materials, and instruments are developed and scattered. Therefore, it is important to raise students' awareness of aptitude and career path with customized education tailored to students. Conventional education platforms have very difficult to choose the right materials for students because of the spread of educational programs and institution materials. To solve this, we propose a customized recommendation approach to recommend customized educational service materials and institution for students to teachers, which helps teachers conveniently choose materials suitable for their respective environments. On this new platform, the CNN algorithm provides recommended content for classes and students. For real service on the educational service platform, we implement this system for Jeil edus business. Through this mechanism, we expect to improve the quality of education by helping to select the right service.

• Journal of the Korean Society of Systems Engineering
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• v.12 no.1
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• pp.89-103
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• 2016

Due to safety of the plant, it became very clear the importance of study occurrence reactor coolant system (RCS) issues specially the primary water stress corrosion cracking (PWSCC). The Systems Engineering (SE) approach is characterized by the application of a structured engineering methodology for the design of a complex system or component. Robotic devices have been used for internal inspection, maintenance and performing remote welding and inspection in high-radiation areas. In this paper, PWSCC overview and inlay and over lay welding methodology introduced, concept of robotic device that can be inserted into the piping via Steam Generator (SG) main way to access to primary piping of pressurized water reactor (PWR) is developed based on SE methodology. A 3D model of the inspection system was developed along with the APR1400 (Advanced Power Reactor)reactor coolant systems (RCS) and internals with virtual 3D simulation of the operation for visualization to prove the validity of the concept.

• Journal of the Korean Society of Systems Engineering
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• v.12 no.1
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• pp.25-40
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• 2016

The Systems Engineering (SE) approach is characterized by the application of a structured engineering methodology for the design of a complex system or component. In this study, the SE methodology is used to design a nondestructive inspection system for Bottom Mounted Instrumentation (BMI) nozzles. We developed a system that enables nondestructive inspection of BMI nozzles during regular refueling outage without removing the reactor internals. A special ultrasonic (UT) probe is introduced to scan and detect cracks within the weld region of the nozzle. A 3D model of the inspection structure system was developed along with the reactor pressure vessel (RPV) and internals which permits a virtual 3D simulation of the operation to check the design concept and effectiveness of the system and to provide a good visualization of the system. This approach allows for a virtual walk through to verify the proposed BMI nozzle inspection system.

• International Journal of Advanced Culture Technology
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• v.5 no.1
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• pp.9-16
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• 2017

In an English multiple Wh-construction with two wh-words, only a higher-located wh-word in a sentence structure is allowed to pre-pose to the Spec of CP, which has been known as a Superiority Effect(SE). Contrary to English, Korean and Japanese have been known not to respect SE, and this phenomenon has been called an Anti-Superiority Effect(ASE). Recent studies including Takita et al(2007) and Harada(2015) among others, however, have suggested exceptional cases to ASE in Japanese, and attempted to explain them through a feature checking mechanism within the Minimalist Program(MP) by Chomsky(1995, 1998). Such explanations of MP, which are based on the abstract feature checking system, have recently been considered just as a kind of technicalia and should be backed up with further empirical evidence. In this paper, I show that there are also exceptions to ASE in Korean, and the exceptional cases to ASE both in Korean and Japanese can be well explainable based on the empirical evidence of Korean/Japanese morpho-syntax.

• International Journal of High-Rise Buildings
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• v.10 no.2
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• pp.99-107
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• 2021

This research investigates the potential of Adaptive TMDs for tall building damping. The Adaptive TMD under consideration is based on real-time controlled hydraulic dampers generating purely dissipative control forces. The control approach is designed to enhance the Adaptive TMD efficiency for moderate wind loads with return periods below 50 years. The resulting enhanced TMD efficiency is used to reduce the pendulum mass by 15% compared to the passive TMD while still guaranteeing the acceleration limits of the one and ten year return period winds. Furthermore, the adaptive control approach is designed to disproportionally increase the controlled damping force at wind loads with return periods of 50 years and more in order to reduce the maximum relative motion of the Adaptive TMD with only 85% pendulum mass. Compared to the passive TMD with 100% pendulum mass the maximum relative motion is reduced by 20%. Both the pendulum mass reduction and the maximum relative motion reduction significantly reduce the foot print of the Adaptive TMD which is highly desirable from the economic point of view.

• Journal of Korean Society for Quality Management
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• v.32 no.4
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• pp.1-14
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• 2004

Nuclear project company establishes and maintains its QA system in the conformance with applicable Codes & Standards and contract provisions. Certifying agency(e.g., Korea Electric Association) or project owner appraises the effectiveness of the company QA system by surveying or auditing it. However, although the company fulfills the requirements of this survey/audit, the capability level of its nuclear QA system is not appraised numerically and developed in that KEPIC QAP-1, used by the company as a nuclear QA guidebook, does not describe an approach for managing the capability level of the QA system. This study evaluates the characteristics of QAP-1 from the viewpoint of SE-CMM(Capability Maturity Model for Systems Engineering) in order to suggest a possible solution.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.25 no.11
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• pp.51-58
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• 2007

• Journal of the Semiconductor & Display Technology
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• v.20 no.3
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• pp.11-17
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• 2021

I performed a semi-analytical numerical analysis of the effects of core size and electric field intensity on the light emission wavelength of CdSe/ZnS quantum dots (QDs). The analysis used a quantum mechanical approach; I solved the Schrödinger equation describing the electron-hole pairs of QDs. The numerical solutions are described using a basis set composed of the eigenstates of the Schrödinger equation; they are thus equivalent to analytical solutions. This semi-analytical numerical method made it simple and reliable to evaluate the dependency of QD characteristics on the QD core size and electric field intensity. As the QD core diameter changed from 9.9 to 2.5 nm, the light emission wavelength of CdSe core-only QDs varied from 262.9 to 643.8 nm, and that of CdSe/ZnS core/shell QDs from 279.9 to 697.2 nm. On application of an electric field of 8 × 10⁵ V/cm, the emission wavelengths of green-emitting CdSe and CdSe/ZnS QDs increased by 7.7 and 3.8 nm, respectively. This semi-analytical numerical analysis will aid the choice of QD size and material, and promote the development of improved QD light-emitting devices.

• Analytical Science and Technology
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• v.37 no.4
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• pp.230-238
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• 2024

This study evaluates a method for quantifying selenium (Se) concentration in soil using inductively coupled plasma mass spectrometry (ICP-MS), with oxygen as a reaction gas. This approach addresses the challenge of detecting low levels of Se in complex soil matrices and aims to effectively minimize interference problems typically associated with argon plasma in traditional ICP-MS analyses. The analytical method utilizes conditions optimized for minimizing spectral interference and were validated by linearity, accuracy, precision, limit of detection (LOD), and limit of quantification (LOQ). The method demonstrated good linearity, high accuracy (90-97 %), and remarkable sensitivity, achieving detection and quantification limits of 0.15 ㎍/kg and 0.44 ㎍/kg, respectively. Developed analysis method for Se in soil was applied to field samples in the different regions of South Korea and Se concentration ranged from 0.11 to 0.52 mg/kg. Correlation analysis between Se concentration and soil properties showed that Se concentration was significantly correlated with cation exchange capacity (CEC) and available phosphorus among other soil properties.