• Carbon letters
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• v.14 no.1
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• pp.34-39
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• 2013

Acrylonitrile (AN)-acrylamide (AM) copolymers were prepared by nitric acidic hydrolysis of homopolyacrylonitrile. The acrylamino group increased as a function of hydrolysis time, while crystallinity decreased. Differential scanning calorimetry and a thermal gravimetric analysis indicated that the acylamino introduced by acidic hydrolysis effectively enhanced the cyclization reaction at low temperature due to the change of the cyclization reaction mechanism. Char-yield of AN-AM copolymers also gradually increased with increasing hydrolysis time. The maximum char-yield was 49.48% when hydrolized at $23^{\circ}C$ in 65% nitric acid solution for 18 h, which was 30% higher than that of non-acidic hydrolysis of homopolyacrylonitrile. Simulation of the practical process also showed an increase of char yields, where the char yields were 55.43% and 62.60% for homopolyacrylonitrile and copolyacrylonitrile, respectively, with a hydrolysis time of 13 h.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.1
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• pp.1-7
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• 2013

Pneumatic cylinders are widely used to actuators in automatic equipments because they are relatively inexpensive, simple to install and maintain, offer robust design and operation, are available in a wide range of standard sizes and design alternatives. This paper presents a comparative study among the dynamic characteristics of meter-out and meter-in speed control of pneumatic cushion cylinders with a relief valve type cushion mechanism. Because of the nonlinear differential equations and a requirement for simultaneous iterative solution in a mathematical model of a double acting pneumatic cushion cylinder, a computer simulation is carried out to investigate pressure, temperature, mass flow rate in cushion chamber and displacement and velocity time histories of piston under various operating conditions. It is found that the piston velocity and pressure response in meter-in speed control are more oscillatory than with meter-out those when pneumatic cushion cylinders are driven at a high-speed. In meter-out speed control, the effective area of the flow control valve is larger than that of meter-in, and the supply pressure has to be much higher than the pressure required to move the load because it has also to overcome the back pressure in cushion chamber.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.1
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• pp.147-154
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• 2012

The number of vehicles applied diesel engine are rapidly rising for fuel economy. Accompanying this trend, application of an after-treatment system is strictly required as a result of reinforced emission regulation. The Diesel Particulate Filter (DPF) system is considered as the most efficiency method to reduce particulate matter (PM) by car makers but also in retrofit market. In recently, various kinds of partial flow DPF are widely used for proper filtration performance and reducing of pressure drop but it is difficult to define the characteristics of these filters because the filtration mechanism is obscure according to the status of these systems. In this paper we investigated the characteristics of cell open type DPF according to the status of filter especially, PM loading. The PM loading mass in the p-DPF are predicted from increase of differential pressure of DPF and the trend of filtration efficiency so that we can measure filtration efficiency and Balance Point Temperature (BPT) of this p-DPF according to PM loading.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.1
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• pp.70-81
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• 2010

A mathematical model is formulated to study the effect of wall mass on the thermal performance of four different houses of different construction. This analytical study was motivated by the experimental work of Burch et al. An analytical solution of one -dimensional, linear, partial differential equation for wall temperature profiles and room air temperatures is obtained using the Laplace transform method. Typical Meteorological Year data are processed to yield hourly average monthly values. These discrete data are then converted to a continuous, time dependent form using a Fast Fourier Transform method. This study is conducted using weather data from four different locations in the United States: Albuquerque, New mexico; Miami, Florida; Santa Maria, California; and Washington D.C. for both winter and summer conditions. A computer code is developed to calculate the wall temperature profile, room air temperature, and energy consumption loads. Three sets of results are calculated one for no auxiliary energy and two for different control mechanism -- an on-off controller and a proportional controller. Comparisons are made for the cases of two controllers. Heavy weight houses with insulation in mild weather areas (such as August in Santa Maria, California) show a high comfort level. Houses using proportional control experience a higher comfort level in comparison to houses using on-off control. The result shows that there is an effect of mass on the thermal performance of a heavily constructed house in mild weather conditions.

• Journal of Haehwa Medicine
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• v.18 no.2
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• pp.37-45
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• 2009

In early 1970s, Electronic Manometers were researched and developed for modernization and objectification of pulse diagnosis. Method of finger pressing, also known as cuffs pressing, is essential for sensing a pulse wave. I think comprehension and deduction of problem from the existing Hi-soo type electronic manometer, will be important for making a better one. The Hi-soo type electronic manometer is constructed of cuff pressing type sensor, differential amplifier, transmitter and recorder. Pulse movement and pulse wave, gauging blood flow, is analyzed by pulse image of "Yixuerumen(醫學入門)". At standard of pulse wave, huanmai(緩脈) is distinguish from chishu(slow and fast, 遲數), fushen(float and sink, 浮沈), interference wave, modificated wave, and phase angel. The Hi-soo type electronic manometer had no explanation of formational mechanism, significantly different with pulse wave which is early known and reported. The strength of Hi-soo type electric manometer is use of cuff pressing type sensor. Above all, the importance of electric manometer is reading the pulse movement accurately then expressing it as pulse wave. From now on the improvement of precise sensor should make a progress.

• Korean Journal of Oriental Medicine
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• v.16 no.3
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• pp.33-44
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• 2010

Pulse diagnosis is considered one of the most important diagnostic methods in traditional Korean medicine. Nonetheless, there have been troubles of using pulse diagnosis practically, for the lack of its differential standards and standardized terminology. Rapid pulse belongs to the several traditional pulse types. Rapid pulse was first mentioned in the chinese medical book Haungdineijin that matched it to the fever as well as yang in the human body. Meanwhile, chinese doctors in Ming Ching dynasty of China suggested that rapid pulse meant more of the yin, cold-related reaction than yang and fever. In this study, we organized the past arguments of the rapid pulse and went back tracking what biological activities could be possibly linked to the rapid pulse. Thus, we figured out that the inflammatory mechanism has a close connection with the rapid pulse. The definition of the rapid pulse in Haungdineijin was indicating the acute inflammatory response, while in Ming Ching dynasty, it indicated the chronic inflammation. This is the deficiency-excess pattern of the rapid pulse. Furthermore, we discussed the nonexpression pattern of the rapid pulse which could be happened in case of the heat stroke, etc.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.3
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• pp.175-184
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• 2004

Ground-borne noise and vibration generated by underground transit system has been recognized as an important environmental problem. This study reviews several of the procedures that have been used to predict ground-borne vibration. The vibration responses are measured at three sites that have different soil qualities. The measured vibration levels are compared with the predicted results by previously used vibration level prediction models. There are some drawbacks to apply these prediction models to selected sites because most of the existing prediction models are primarily based on empirical data and all of them lack of analytical models for the mechanism of ground-borne vibration generation. radiation, and propagation. In this study a numerical method, which is based on explicit differential method, is used to compensate for the shortcomings of existing prediction models. Although numerically computed results are not quantitatively in good agreement with the measured results, the trends are comparable in the sense that vibration level does not decrease monotonically with distance. Also, the site with the deepest tunnel gives the highest vibration level.

• Development and Reproduction
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• v.1 no.1
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• pp.45-56
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• 1997

Befor fertilization, mammalian oocytes undergo meiotic maturation, which consists of nuclear and cytoplasmic differentiation. In this study, changes of $Ca^{2+}$ stores in mouse oocytes were examined during meiotic maturation and the role of $Ca^{2+}$ in the regulation of the maturation was investigated by using monoclonal antibodies against smooth endoplasmic reticulum $Ca^{2+}$-ATPase(SERCA-ATPase) and calreticulin. Observations were made under epifluorescence microscope and/or confocal laser scanning microscope. In immature oocytes which did not resume meiotic maturation, SERCA-ATPases were mostly localized in the vicinity of the germinal vesicle and calreticulins were distributed evenly throughout the cytoplasm. In mature oocytes, SERCA-ATPases were observed throughout the cytoplasm, butwere absent from the nuclear region. In contrast, calreticulins were localized mostl in the cortex of the oocyte and were absent from the cytoplasm. However, bright fluoresence stainings were wbserved in the perimeiotic spindle region of mature oocyte when labeled with antibodies against calreticulin. These results indicate that mouse oocytes undergo distinct rearrangement of the localization of $Ca^{2+}$-ATPases and calreticulins during meiotic maturation. Thus it can be suggested that redistribution of the $Ca^{2+}$ stores, as revealed by differential fluorescence stainings, is deeply involved in the regulatory mechanism of mammalian oocyte maturation.

• Mass Spectrometry Letters
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• v.4 no.1
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• pp.1-9
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• 2013

Fungal biotechnology has been well established in food and healthcare sector, and now being explored for lignocellulosic biorefinery due to their great potential to produce a wide array of extracellular enzymes for nutrient recycling. Due to global warming, environmental pollution, green house gases emission and depleting fossil fuel, fungal enzymes for lignocellulosic biomass refinery become a major focus for utilizing renewal bioresources. Proteomic technologies tender better biological understanding and exposition of cellular mechanism of cell or microbes under particular physiological condition and are very useful in characterizing fungal secretome. Hence, in addition to traditional colorimetric enzyme assay, mass-spectrometry-based quantification methods for profiling lignocellulolytic enzymes have gained increasing popularity over the past five years. Majority of these methods include two dimensional gel electrophoresis coupled to mass spectrometry, differential stable isotope labeling and label free quantitation. Therefore, in this review, we reviewed more commonly used different proteomic techniques for profiling fungal secretome with a major focus on two dimensional gel electrophoresis, liquid chromatography-based quantitative mass spectrometry for global protein identification and quantification. We also discussed weaknesses and strengths of these methodologies for comprehensive identification and quantification of extracellular proteome.

• Wind and Structures
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• v.13 no.2
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• pp.127-144
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• 2010

Pressure measurements on static and autorotating flat plates have been recently reported by Lin et al. (2006), Holmes, et al. (2006), and Richards, et al. (2008), amongst others. In general, the variation of the normal force with respect to the angle of attack appears to stall in the mid attack angle range with a large scale separation in the wake. To date however, no surface pressures have been measured on auto-rotating plates that are typical of a certain class of debris. This paper presents the results of an experiment to measure the aerodynamic forces on a flat plate held stationary at different angles to the flow and allowing the plate to auto-rotate. The forces were determined through the measurement of differential pressures on either side of the plate with internally mounted pressure transducers and data logging systems. Results are presented for surface pressure distributions and overall integrated forces and moments on the plates in coefficient form. Computed static force coefficients show the stall effect at the mid range angle of attack and some variation for different Reynolds numbers. Normal forces determined from autorotational experiments are higher than the static values at most pitch angles over a cycle. The resulting moment coefficient does not compare well with current analytical formulations which suggest the existence of a flow mechanism that cannot be completely described through static tests.