• Bulletin of the Korean Chemical Society
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• v.5 no.2
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• pp.65-68
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• 1984

Reactions of $MoOCl_5^{2-}$ with $[PW_{11}O_{39}]^{7-}\;and\;[SiW_{11}O_{39}]^{8-}$ have been studied spectrophotometrically and several transient complexes have been discovered. Transient species initially formed are probably $[Mo_2O_4(PW_{11}O_{39})_2]^{12-}\;and\;[Mo_2O_4(SiW_{11}O_{39})_2]^{14-}$. Spectra change gradually, indicating formation of transient isomers of $[PMoW_{11}O_{40}]^{4-}\;and\;[SiMoW_{11}O_{40}]^{5-}$, which again transform into the stable isomers. The transient isomers absorb light much more strongly than the stable isomers in the visible range.

• Bulletin of the Korean Chemical Society
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• v.6 no.5
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• pp.277-279
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• 1985

Orbital interactions of the types, ${\sigma}-{\pi},\;{\sigma}^*-{\pi},\;{\sigma}-{\pi}^*\;and\;{\sigma}^*-{\pi}^*$ are investigated for the rotamers of ${\alpha}$-X-acetones (X = F and Cl) using STO-3G method of calculation. It was found that the interactions are possible only in gauche forms, and the ${\sigma}^*-{\pi}^*$ interactions are in general greater than the $\sigma-\pi$ interactions due to the greater overlap, in spite of the greater energy gap involved; the greater ${\sigma}^*-{\pi}^*$ interaction causes greater lowering of ${\pi}^*$ level relative to the lowering of ${\sigma}$ in the ${\sigma}-{\pi}$ interaction so that both ${\sigma}-{\pi}^*$ and $n-{\pi}^*$ interactions are enhanced in the gauche forms. The extra stability of the gauche form and the red shift in the $n-{\pi}^*$ transition are thus found to be natural corollaries of the greater ${\sigma}^*-{\pi}^*$ interaction in the gauche forms.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.1
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• pp.32-37
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• 2021

This study proposes a DC series arc fault detector using a frequency analysis method called the discrete wavelet transform (DWT), in which the processing speed of the DWT algorithm is improved effectively. The processing time can be shortened because of the time characteristic of the DWT result. The performance of the developed DC series arc fault detector for a large photovoltaic system is verified with various DC series arc generation conditions. Successful DC series arc detection and improved calculation time were both demonstrated through the measured actual arc experimental result.

• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.5
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• pp.545-551
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• 2022

We proposed a design method for constant current pyro squib circuit. The current method using N MOSFET for the stability problem has a weakness of the current change, requiring a new design. This paper identified the problem with conventional squib circuit where the current is reduced by 25 % when maximum resistance is 3 ohms. Thus, we proposed a stable constant current driving circuit using P MOSFET and PNP BJT. We confirmed stable constant circuit operation through simulations and measurements of the proposed circuit design where the current did not change until the resistance reached 3 ohms.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.4
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• pp.57-63
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• 2008

In this paper, the dependence of MOSFET performance on the channel stress is characterized in depth. The tensile and compressive stresses are applied to CMOSFET using a nitride film which is used for the contact etch stop layer (CESL). Drain current of NMOS and PMOS is increased by inducing tensile and compressive stress, respectively, due to the increased mobility as well known. In case of NMOS with tensile stress, both decrease of the back scattering ratio ($\tau_{sat}$) and increase of the thermal injection velocity ($V_{inj}$) contribute the increase of mobility. It is also shown that the decrease of the $\tau_{sat}$ is due to the decrease of the mean free path ($\lambda_O$). On the other hand, the mobility improvement of PMOS with compressive stress is analyzed to be only due to the so increased $V_{inj}$ because the back scattering ratio is increased by the compressive stress. Therefore it was confirmed that the device performance has a strong dependency on the channel back scattering of the inversion layer and thermal injection velocity at the source side and NMOS and PMOS have different dependency on them.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.04a
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• pp.595-597
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• 2017

Despite rapid growth of the global SW market, the Korean market still has a long way to go to impact global power nations. What is the reason that holds back of the No. 1 high-speed Internet country in terms of SW development? It is lack of the foundation for development of the Korean SW industry. In this context, the Korean government declared SW-oriented society and developed polices for each sector; Regarding movement that tries to apply the SW partitioning order institution in public sector to IT projects, this research aims to study SI project problems expected when conducting the SW partitioning order institution and improvements focusing on the public sector that accounts for about 30% of the entire SW industry. SW partitioning order institution is divided into planning-design and development-realization stages, which may cause problems when it is applied to SI projects. As such, the study analyzed SI projects and separate and partitioning order, exemplary cases and examples of industrial projects related to partitioning order, and drew improvement measures from institutional, technological and managerial viewpoints. The research aims to help people involved in IT projects sell SW at proper prices and improve the environment, and presents directions to create a system that strengthens competitiveness of the SW industry and SI projects by providing solutions to problems that suppliers and demanders should recognize before implementing the SW partitioning order institution.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.3 s.345
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• pp.1-8
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• 2006

In this paper, reliability (HCI, NBTI) and device performance of nano-scale CMOSFETs with different channel stress were investigated. It was shown that NMOS and PMOS performances were improved by tensile and compressive stress, respectively, as well known. It is shown that improved device performance is attributed to the increased mobility of electrons or holes in the channel region. However, reliability characteristics showed different dependence on the channel stress. Both of NMOS and PMOS showed improved hot carrier lifetime for compressive channel stress. NBTI of PMOS also showed improvement for compressive stress. It is shown that $N_{it}$ generation at the interface of $Si/SiO_2$ has a great effect on the reliability. It is also shown that generation of positive fixed charge has an effect in the NBTI. Therefore, reliability as well as device performance should be considered in developing strained-silicon MOSFET.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.6
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• pp.201-208
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• 2014

In this paper, we propose the classifier structure design algorithm using DTW. Proposed algorithm uses DTW result to design the binary tree architecture based on the SVM which classify the multi-class data. Design the binary tree architecture for Support Vector Machine(SVM-BTA) using the threshold criterion calculated by the sum columns in square matrix which components are the reference data from each class. For comparison the performance of the proposed algorithm, compare the results of classifiers which binary tree structure are designed based on database and k-means algorithm. The data used for classification is 333 signals from 18 classes of underwater transient noise. The proposed classifier has been improved classification performance compared with classifier designed by database system, and probability of detection for non-biological transient signal has improved compare with classifiers using k-means algorithm. The proposed SVM-BTA classified 68.77% of biological sound(BO), 92.86% chain(CHAN) the mechanical sound, and 100% of the 6 kinds of the other classes.

• Journal of Korean Foot and Ankle Society
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• v.7 no.1
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• pp.7-12
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• 2003

Purpose: To study the relationship of the 1st to 2nd intermetatarsal angle(1-2 IMA) between the intra-operative and weight bearing postoperative anterior-posterior(AP) radiography, and evaluate the intra-operative predictability for the postoperative 1-2 IMA after proximal metatarsal osteotomy(PMO) in the hallux valgus deformity. Materials and Methods: 20 cases of moderate to severe hallux valgus patients were included in this study. After the oblique PMO(Ludloff procedure) was performed and the osteotomy site was fixed temporarily, the AP view was taken intra-operatively. About 10 weeks after surgery, postoperative weight bearing AP view was taken. The pre -. intra -, and postoperative 1-2 IMAs were compared and ana lysed statistically. Results: The 1-2 IMAs of the weight bearing preoperative, non-weight bearing intra-operative and weight bearing postoperative AP view were $15.9^{\circ}{\pm}1.8^{\circ},\;4.7^{\circ}{\pm}2.1^{\circ}$, and $6.8^{\circ}{\pm}2.5^{\circ}$ (Mean${\pm}$SD) respectively. The postoperative 1-2 IMA was greater than intra-operative measurement by $2.1^{\circ}{\pm}1.8^{\circ}$ (range; $-1^{\circ}$ to $6^{\circ}$) which was stastistically significant(p<0.05). To get less than $9^{\circ}$ postoperatively as an average normal, intra-operative 1-2 IMA should be within $3.8^{\circ}$ to $5.2^{\circ}$ (95% confidence interval), and intra-operative 1-2 IMA should be within $3.4^{\circ}{\pm}$to $5.4^{\circ}$(95% confidence interval) to get more than $6^{\circ}$ difference between preoperative and postoperative 1-2 IMA, which is regarded as more than average correction by the distal metatarsal osteotomy. Conclusion: In hallux valgus surgery, it should be considered that intra-operative 1-2 IMA was less than the postoperative. To achieve postoperative 1-2 IMA less than $9^{\circ}$ and more than correction angle of $6^{\circ}$, it is suggested that the intra-operative 1-2 IMA should be measured less than about $5^{\circ}$.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.15 no.1
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• pp.44-48
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• 2015

Mucopolysaccharidosis (MPS) IIIA is a lysosomal storage disorder caused by abnormalities of the enzyme Heparan N-sulfatase that is required for degradation of heparan sulfate. The patient in this study was a 5 year-old boy who presented with macrocephaly and developmental delay. Urinary excretion of glycosaminoglycan was increased (26 g/moL creatinine, reference range: <7 g/moL creatinine) and a distinct band of heparan sulfate was shown in electrophoresis. Heparan N-sulfatase activity was significantly decreased in skin fibroblasts (0.2 pmoL/min/mg protein, reference range: 9-64 pmoL/min/mg protein). PCR and direct sequencing analysis of the SGSH gene showed compound heterozygous mutations: c.1040C>T (p.S347F) and c.703G>A (p.D235N). This is the first report for a Korean patient with MPS IIIA who was confirmed by biochemical investigation and molecular genetic analyses.