• Macromolecular Research
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• v.14 no.3
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• pp.300-305
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• 2006

The chemical structure of a semi-aromatic polyimide-I, which was prepared by the chemical imidization of cyclopentanetetracarboxylic dianhydride and 2,2-bis(4-aminophenyl)hexafluoropropane, was characterized by $^{13}C-NMR$ spectroscopy. The chemically imidized polyimide-I was used for the preparation of a photosensitive polyimide (PSPI) through the addition of benzophenone and benzophenone oxime hexamethylene diurethane (BOHD), a photobase generator containing oxime-urethane groups. The polyimide-I film containing benzophenone and BOHD was not soluble in 2.38 wt% tetrabutylammonium hydroxide solution in $H_2O$. However, it became soluble following irradiation with 310 nm UV light. A positive tone image with a resolution of $5{\mu}m$ was obtained with this PSPI, having sensitivity($D_c$) of $1.2J/cm^2$ and contrast(${\gamma}_p$) of 1.08. Thus, a polyimide, which is not intrinsically photosensitive, can become photosensitive through the addition of a photobase generator containing oxime-urethane groups as a photosensitive compound.

• IE interfaces
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• v.13 no.4
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• pp.658-667
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• 2000

Seasonal variation of natural gas demand coupled with rigid and stable import pattern of gas represents the characteristic feature of the Korean Liquified Natural Gas(LNG) industry. This attribute has required a huge amount of investment for the construction of storage facility. Thus, to minimize the supply cost, it is legitimate to reduce storage requirement itself. In this study, we combine three alternative methods to deal with the storage requirement to minimize the supply cost. Those are (1) adding additional storage tanks, (2) inducing large firm customers, and (3) constructing gas-turbine self generation facilities. Methodologically, we employ the mixed integer program (MIP) to optimize the system. The model also consider demand and price-setting scheme in separate modules. From the results, it is shown that if alternatives are combined optimally, a number of storage tanks can be reduced substantially compared with the original capacity plan set by the industry authorities. We perform various sensitivity analyses to check the robustness of the results. The methodology presented in this study can be applied to the other physical network industry, such as hydraulics. The empirical results will shed some light on the rationalization of capacity planning of the Korean natural gas industry.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.11
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• pp.9-16
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• 2010

This paper examines the temperature characteristics of an Optical CT (optical current transformer) using the Faraday effect for measuring high current in a super high voltage-power apparatus. It is performed as follows by the sensor for embodying Faraday effect. $\cdot$ A single-mode optical fiber capable of maintaining a polarization state is used. $\cdot$ A light source is applied at 1310[nm] to a Laser Diode. $\cdot$ The Linear of Faraday effect to a large current is evaluated and $\cdot$ A possible application using an Optical CT was shown. An Influence of Faraday effect to the surrounding temperature measured -40~50[$^{\circ}C$], and the characteristic of the current sensitivity was reported. An application using the results of the temperature compensation system was used in order to compensate for surrounding temperatures. A possibility of applying Optical CT for electric power apparatus was advanced further. We were able to confirm that this temperature calibration method can minimize the fluctuation of the output signal depending on the temperature conditions.

• Journal of Power Electronics
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• v.10 no.2
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• pp.115-124
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• 2010

In this paper, a simple yet efficient auto mode-hop ripple control structure for buck converters with light load operation enhancement is proposed. The converter, which operates under a wide range of input and output voltages, makes use of a state-dependent hysteretic comparator. Depending on the output current, the converter automatically changes the operating mode. This improves the efficiency and reduces the output voltage ripple for a wide range of output currents for given input and output voltages. The sensitivity of the output voltage to the circuit elements is less than 14%, which is seven times lower than that for conventional converters. To assess the efficiency of the proposed converter, it is designed and implemented with commercially available components. The converter provides an output voltage in the range of 0.9V to 31V for load currents of up to 3A when the input voltage is in the range of 5V to 32V. Analytical design expressions which model the operation of the converter are also presented. This circuit can be implemented easily in a single chip with an external inductor and capacitor for both fixed and variable output voltage applications.

• Journal of Sensor Science and Technology
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• v.19 no.6
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• pp.483-489
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• 2010

Display quality depends on panel temperatures. To compensate it, temperature sensor was integrated on the panel. The conventional temperature sensor integrated on the panel needs external reference resistor. Since the resistance of external resistor can vary according to the variation of the environment temperature, the conventional temperature sensor can make error in temperature sensing. The environmental temperatures can change by the back light unit, driving circuits or chips. In this paper, we proposed a integrated temperature sensor on display panel which does not need external reference resister. Instead of external reference resistor, we used two materials which have different temperature coefficient in resistivity. They are connected serially and the output voltage was measured at the point of connection with the applied voltage to both ends. The proposed sensor was fabricated with indium tin oxide(ITO), and Mo metal electrode temperature sensor which were connected serially. We verified the temperature senor by the measurements of sensitivity, lineality, hysteresis, repeatability, stability, and accuracy.

• Science of Emotion and Sensibility
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• v.15 no.3
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• pp.355-366
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• 2012

This paper analyses the sensory responses of Chinese female consumers towards different designs of perfume bottles with particular attention to the existence of logos on them. We used total 40 samples of the perfume bottles, 20 with logos on them and 20 without, and the results show that young Chinese female consumers prefer simple designs over complex designs that contain different types of free curves with vivid colors. In addition, the existence of logos on bottles was found not to change the responses significantly, meaning that the logos on bottles do not affect sensibility of Chinese female towards perfume bottles. A logo's impacts on the bottle depended in part on the bottle's color and shape. Overall, a perfume bottle with simple shapes and light colors became regarded as more resplendent when the logo was added, but a bottle with more complex shapes and vivid colors tended to become regarded as plainer after adding the logo. This shows that a logo serves as a conciliatory element in the impression of the whole bottle in the 'resplendent-plain' category.

• The Korean Journal of Cytopathology
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• v.4 no.1
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• pp.9-15
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• 1993

The aim of the present study is to demonstrate the usefulness of intraoperative fine needle aspiration (FNA) of pancreatic lesions in 30 patients. A conclusive diagnosis was done in 27 patients and the diagnoses of three patients were deferred. No complications followed the procedure. Based on histologic findings of the resected specimens in 20 cases and of cell blocks in 10 cases, the final diagnoses were adenocarcinoma in 19 cases, chronic pancreatitis in nine cases and tuberculosis in two cases. The sensitivity, specificity and diagnostic accuracy were 95%, 100% and 96% resepectively and there were no false positives. The smear of aspirate was stained with toluidine blue and examined by light microscope. The presence of there-dimensional clusters of disoriented cells and the increased nuclear/cytoplasmic ratio with large prominent nucleoli were the most helpful criteria for a diagnosis of malignancy in the pancreas. The intraoperative FNA of pancreatic lesions was considered as a simple, safe, and highly specific and sensitive tool in differentiating benign from malignant lesions. The intraoperative FNA can be recommended as the first tool of choice of intraoperative diagnostic procedure in lesions of the pancreas.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.1
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• pp.171-176
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• 2007

An important challenging issue in the automotive industry is the light-weight, safe design and enhancement of crash response of an auto-body structures. These objectives lead to increasing adoption of high strength steel sheet for inner and outer auto-body members. This paper evaluates the dynamic tensile characteristics of high strength steel sheets, HS45R, TRIP60, DP60 and DP100, along the rolling direction and transverse direction. Static tensile tests were carried out at the strain rate of 0.003/sec using the static tensile machine (Instron 5583). Dynamic tensile tests were carried out at the range of strain rate from 0.1/sec to 200/sec using a high speed material testing machine developed. The tensile tests acquire stress-strain relation and strain rate sensitivity of each material. The experimental results show two important aspects for high strength steels: the flow stress increases as strain rate increases; the strain hardening decreases as the tensile stress increases. The experiments also produce interesting results that the elongation does not decrease even when the strain rate increases.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.2
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• pp.144-150
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• 2003

The chalcogenide glasses of thin films have the superior property of photoinduced anisotrophy(PA). In this study, we observed the linear dichroism using the irradiation with Polarized He-Ne laser light in the Ag/As$_{40}$ Ge$_{10}$Se$_{15}$ S$_{35}$ multi-layer. Multilayer structures were formed by alternating metal(Ag) and chalcogenide(As$_{40}$ Ge$_{10}$Se$_{15}$ S$_{35}$) thin film. The Ag Polarized photodoping result in reducing the time of saturation anisotropy and increasing the sensitivity of linearly anisotropy intensity As the results, the Ag polarized photodoping will be have a capability of new method that suggests more improvement of photoinduced anisotropy property in the thin films of chalcogenide.ogenide.ide.

• Polymer(Korea)
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• v.24 no.3
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• pp.407-417
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• 2000

Photosensitive polyimides having cyclobutane or phenyl and aromatic sulfonyloxyimide units in the main chain have been synthesized and the photodegradation behavior was investigated in relation with the polymer structure. The polyimides were prepared by condensation polymerization of N-hydroxyl and sulfonyl chloride. The prepared polyimides were stable up to 25$0^{\circ}C$ without thermal degradation. It has been found that the photodegradation of polyimides upon irradiation of 254 nm UV light results from scission of N-O bonds or ring opening of imides moiety by spectroscopic measurements. The polyimides were useful as positive working photodegradable polymers. Especially, the positive tone image of polyimide containing a pyromellitic diimide moiety exhibited high sensitivity and resolution.