• Transactions of the KSME C: Technology and Education
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• v.3 no.4
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• pp.273-283
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• 2015

In this study, we suggested the methodology and the results of planning of promising technologies in mechanical engineering by focusing on the case of the Korea Institute of Machinery and Materials (KIMM). For dedicated commitment to planning of promising technologies, KIMM newly introduced task-force called as 'specialist unit'. In addition, KIMM combined the investigation of external environments with the analysis of internal capabilities of KIMM and utilized the bibliographic coupling analysis in the process of the exploring sub themes. Finally, we provided 8 promising fields and their sub themes in the mechanical engineering. Our study contributed to the strategic development of the main research programs of KIMM. Our findings can be also utilized as the best practice of planning of promising technologies in the field of mechanical engineering.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.5
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• pp.423-432
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• 2023

With the increasing demand for mobile devices featuring multi-touch operation, extensive research is being conducted on touch screen panel (TSP) Readout ICs (ROICs) that should possess low power consumption, compact chip size, and immunity to external noise. Therefore, this paper discusses capacitive touch sensors and their readout circuits, and it introduces research trends in various circuit designs that are robust against external noise sources. The recent state-of-the-art TSP ROICs have primarily focused on minimizing the impact of parasitic capacitance (Cp) caused by thin panel thickness. The large Cp can be effectively compensated using an area-efficient current compensator and Current Conveyor (CC), while a display noise reduction scheme utilizing a noise-antenna (NA) electrode significantly improves the signal-to-noise ratio (SNR). Based on these achievements, it is expected that future TSP ROICs will be capable of stable operation with thinner and flexible Touch Screen Panels (TSPs).

• Journal of the Korean Magnetics Society
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• v.15 no.5
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• pp.276-281
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• 2005

We have investigated the effects of an external magnetic field on the growth direction and the grain size of electrochemically prepared CoPtP alloys. Electrodeposited CoPtP alloys were synthesized by appling an external magnetic field with 0 to 1 T to the perpendicular direction of the films. In the electrodeposited CoPtP alloys without external magnetic field, the growth direction of the alloys was mixed by fcc (111) and hop (002), but only hop (002) was observed in the alloys with 1 T external magnetic field. CoPtP alloys were grown as the columnar growth and the grain size increases with growing the alloys. With appling an external field, the grain size of the alloys was controlled less than 20 nm which is smaller than single domain of Co, and the easy axis of alloys, hcp (002) direction, was grown perpendicular to the films up to 200 nm. We could obtain the optimal thickness of the alloys and electrodeposition condition from the above results. Coercivity and squareness of CoPtP alloys taken out-of-plane are 6.1 kOe and 0.9, respectively. The magnetic properties of CoPtP alloys were measured by VSM, and the microstructural characterization and crystalline orientation measurement of the alloys were carried out by TEM and XRD.

• Journal of Korean Elementary Science Education
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• v.35 no.1
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• pp.123-135
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• 2016

Interest is one of the important factors in science education. The purpose of this study was to investigate factors affecting the follow-up interest of elementary school students on topics of 'Small Organisms' World'. The follow-up interests of the students on the topic were grouped into three categories; the developed-expanded-deepened (EDD), the simply expanded and maintained (SEM), and the stoped or decreased (SD) types. Each types had specific distinguishing features. Through the examination of students' responses and the in-depth interviews, the factors affecting on the follow-up interests of the students were analyzed. The factors were classified into two types of the external factor and the internal one. While the external factors were mainly related to the instructional materials used in science class and teaching methods, the internal factors were related to the desire for knowing, prior knowledge, students' experience and attitude toward the topics of science. In relation to the types of the follow-up interests, these factors were affected by different causes. The EDD type was most affected by internal factors, such as desire for knowing and prior knowledge. The SEM type was shown to be most affected by external factors, such as instructional materials. The SD type was mainly influenced by external factors, such as teaching methods. From the analysis of internal factors, it was revealed that the attitude and the prior knowledge about the topic are related with the follow-up interests. There was a positive relationship between the levels of science attitude and science knowledge. The students who had EDD type had a higher level of attitude and knowledge. However, there were some students who had higher level of scientific knowledge with SD type. The results of in-depth interviews showed that they were influenced by negative perceptions about science and stress on their grades. In conclusion, each follow-up interest type were caused by the external factors contained in the processes of the science class and the internal ones associated with the individual features and were influenced by the science class. So, the teacher should help the students be able to have the EDD type of follow-up interest which is persisted even after the completion of the science curriculum. For this, when the teachers design science curriculum and plan lesson, they should consider both internal and external factors significantly influencing the students' follow-up interests.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.238-239
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• 2017

Waterproofing is a very important process in terms of durability of buildings. The materials used for waterproofing work to protect the concrete structure from external deterioration factors. In particular, the waterproofing materials applied to the exterior of the concrete structure have various problems due to changes in the external environment and variables in the construction process. The waterproof layer is repeatedly dried and shrunk according to changes in the external moisture environment, and the surface may be deteriorated due to exposure to long-term sunlight. In the case of the roof waterproofing in the structure, the waterproof layer which does not have a sufficient curing period shows much swelling and floating phenomenon. These defects, such as swelling and lifting, account for most of the defects that occur in the waterproof layer of the concrete slabs. Generally, it is difficult to expect the same level of performance as the initial state even if the waterproofing work is repaired when a defect occurs. Therefore, it is possible to reduce the defects of the waterproof layer such as swelling and lifting by forming a waterproof layer which can be integrated with the concrete surface by using a polyurethane type waterproofing material having a relatively low defective ratio compared to other waterproofing materials. So in this study, the basic properties of polyurethane waterproof sheet reinforced with non-woven fabric are investigated in order to understand field applicability.

• Progress in Superconductivity
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• v.14 no.1
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• pp.1-10
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• 2012

We fabricated a closed coils by using resistive-joint method and the joint resistance of the coils were estimated by field decay technique in liquid nitrogen. We used the Runge-kutta method for the numerical analysis to calculate the decay properties. The closed coil was wound by $(Bi,Pb)_2Sr_2Ca_2Cu_3O_x$/Ag tape. Both ends the tape were overlapped and soldered to each other. The current was induced in a closed coils by external magnetic flux density. Its decay characteristic was observed by means of measuring the magnetic flux density generated by induced current at the center of the closed coil with hall sensor. The joint resistance was calculated as the ratio of the inductance of the loop to the time constants. The joint resistances were evaluated as a function of critical current of loop, contact length, sweep time, and external magnetic flux density in a contact length of 7 cm. It was observed that joint resistance was dependent on contact length of a closed coil, but independent of critical current, sweep time, and external magnetic flux density. The joint resistance was measured to be higher for a standard four-probe method, compared with that for the field decay technique. This implies that noise of measurement in a standard four-probe method is larger than that of field decay technique. It was estimated that joint resistance was $8.0{\times}10^{-9}{\Omega}$ to $11.4{\times}10^{-9}{\Omega}$ for coils of contact length for 7 cm. It was found that 40Pb/60Sn solder are unsuitable for persistent mode.

• Journal of Korean Medical classics
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• v.30 no.1
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• pp.111-133
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• 2017

Objectives : Dryness pathogen, which is one of six pathogenic factors, causes dryness diseases. Currently, the theory on dryness disease is composed of external dryness and internal dryness. External dryness, in turn, is composed of cool dryness and warm dryness. However, these categorizations and their symptoms bear ambiguity for many reasons. Therefore, this paper aims to review various texts in order to study the special features of dryness pathogen and dryness disease. Methods : Texts that deal with dryness pathogen and dryness disease were studied. Most texts are comprised of dissertations and historical medical texts, therefore, CNKI and The Sikuquanshu's databases, and Traditional Chinese Medical(TCM) book webdatabases were utilized. Materials are listed in chronological order, and their main points regarding dryness pathogen and dryness disease are compared. Results & Conclusions : It is difficult to accept the assertion that dryness pathogen does not lead to external dryness. Dryness does not have the elements of chill and fever in itself. Dryness's elements of chill and fever are determined in the ways they combine with each individual element. Moreover, the symptoms of chill and fever on dryness disease are subject to the host's body type. External dryness and internal dryness cannot be discussed within an identical premise. Whereas the dryness in external dryness signifies the cause of a disease, the dryness in internal dryness is the consequence of a disease. In other words, internal dryness revolves around cause of disease and external dryness revolves around the mechanic of disease. It's difficult to determine whether these diseases are caused by dryness or wetness in Autumn. There is an understanding which integrates these together through the Yunqi theory, but it is imperfect.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.3
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• pp.36-43
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• 2016

Carbon fiber-reinforced silicon carbide (Cf-SiC) and SiC / SiC composites have high thermal conductivity, and excellent corrosion and wear resistance, a low coefficient for thermal expansion and are lightweight. This is why they are commonly used in parts of the aerospace industry to develop an aircraft thrust deflector, jet vane, combustion chamber, elevens, body flap, and a shingle. So, understanding how this state-of-the-art Cf-SiC affects both internal and external crack detection and determining issues during the manufacturing process of composite materials, should be evaluated according to valuation techniques in the external environment. In this paper, we apply a non-contact air ultrasonic technique of non-destructive testing techniques to perform a study on internal defect detection identification and assessment of carbon-fiber reinforced silicon carbide composites to perform basic research and applied research.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.21-21
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• 2003

To increase the light-emission efficiency of LED, we increased the internal and external quantum efficiency by suppressing the defect formation in the quantum well and by increasing the light extraction efficiency in LED, respectively. First, the internal quantum efficiency was improved by investigating the effect of a low temperature (LT) grown p-GaN layer on the In$\sub$0.25/GaN/GaN MQW in green LED. The properties of p-GaN was optimized at a low growth temperature of 900oC. A green LED using the optimized LT p-type GaN clearly showed the elimination of blue-shift which is originated by the MQW damage due to the high temperature growth process. This result was attributed to the suppression of indium inter-diffusion in MQW layer as evidenced by XRD and HR-TEM analysis. Secondly, we improved the light-extraction efficiency of LED. In spite of high internal quantum efficiency of GaN-based LED, the external quantum efficiency is still low due to the total internal reflection of the light at the semiconductor-air interface. To improve the probability of escaping the photons outside from the LED structure, we fabricated nano-sized cavities on a p-GaN surface utilizing Pt self-assembled metal clusters as an etch mask. Electroluminescence measurement showed that the relative optical output power was increased up to 80% compared to that of LED without nano-sized cavities. I-V measurement also showed that the electrical performance was improved. The enhanced LED performance was attributed to the enhancement of light escaping probability and the decrease of resistance due to the increase in contact area.

• Smart Structures and Systems
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• v.22 no.1
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• pp.71-79
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• 2018

The nonlinear vibration analysis of a magneto-rheological elastomer (MRE) sandwich plate is conducted experimentally. Experiments have been performed in order to construct the frequency-response curves in the vicinity of the fundamental natural frequency of an MRE sandwich plate (plate A) in either the absence or presence of a localised external magnetic field at 3 different geometrical locations, for both small and medium magnetic fields. Furthermore, experiments have also been conducted on a pure aluminium plate (plate B) with an equal thickness to the MRE sandwich plate (plate A) in order to examine the influence of the MRE layer on the nonlinear dynamics of the system. An electrodynamic shaker was used to directly force each system and the displacement at the centre of the plate was measured. Meanwhile, permanent magnets were used to apply a localised magnetic field for the experiments where the MRE sandwich plate was subject to an external magnetic field. It was observed all the MRE systems displayed strong hardening-type nonlinear behaviour, however, with increasing magnetic field this behaviour transitioned to a weak hardening-type nonlinearity.