• Asian Pacific Journal of Cancer Prevention
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• v.15 no.3
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• pp.1085-1091
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• 2014

Matrix metalloproteinases (MMPs) are a family of zinc dependent extracellular matrix (ECM) remodelling endopeptidases having the ability to degrade almost all components of extracellular matrix and implicated in various physiological as well as pathological processes. Carcinogenesis is a multistage process in which alteration of the microenvironment is required for conversion of normal tissue to a tumour. Extracellular matrix remodelling proteinases such as MMPs are principal mediators of alterations observed in the microenvironment during carcinogenesis and according to recent concepts not only have roles in invasion or late stages of cancer but also in regulating initial steps of carcinogenesis in a favourable or unfavourable manner. Establishment of relationships between MMP overproduction and cancer progression has stimulated the development of inhibitors that block proteolytic activity of these enzymes. In this review we discuss the MMP general structure, classification, regulation roles in relation to hallmarks of cancer and as targets for therapeutic intervention.

• The Transactions of the Korean Institute of Power Electronics
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• v.15 no.3
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• pp.199-206
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• 2010

Matrix converter is an energy conversion device of controlled power semiconductor switches that directly connects the three-phase source to the three-phase load. With no dc-link components for energy storage in the matrix converter the input current depends directly upon the load currents and the switch state of the converter. Therefore the unbalanced and distorted input voltages can result in unwanted output harmonic currents. This paper presents a current compensator based on neural network to improving output current quality for matrix converter under abnormal input voltage conditions. The effectiveness and feasibility of the proposed technique has been proven through numerical simulations and experimental tests.

• Carbon letters
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• v.14 no.1
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• pp.58-61
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• 2013

In this work, the effect of catalysts on the mechanical properties of carbon fibers-reinforced epoxy matrix composites cured by cationic latent thermal catalysts, i.e., N-benzylpyrazinium hexafluoroantimonate (BPH) was studied. Differential scanning calorimetry was executed for thermal characterization of the epoxy matrix system. Mechanical interfacial properties of the composites were studied by interlaminar shear strength (ILSS), critical stress intensity factor ($K_{IC}$), and specific fracture energy ($G_{IC}$). As a result, the conversion of neat epoxy matrix cured by BPH was higher than that of one cured by diaminodiphenyl methane (DDM). The ILSS, $K_{IC}$, $G_{IC}$, and impact strength of the composites cured by BPH were also superior to those of the composites cured by DDM. This was probably the consequence of the effect of the substituted benzene group of BPH catalyst, resulting in an increase in the cross-link density and structural stability of the composites studied.

• Journal of Power Electronics
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• v.18 no.5
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• pp.1325-1335
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• 2018

This paper presents a discontinuous pulse width modulation (DPWM) method to reduce switching losses in an indirect matrix converter (IMC) drive. The IMC has a number of power semiconductor switches. In other words, it consists of a rectifier stage and an inverter stage for AC/AC power conversion, which are composed of 12 and 6 switching devices, respectively. Therefore, the switching devices of the IMC suffer from high switching losses in the IMC drives. Various topologies to reduce switching losses have been studied by eliminating a number of switches from the rectifier stage. In this study, in contrast to prior research, a DPWM method is presented to reduce the switching losses of the inverter stage. The effectiveness of the proposed method to reduce switching losses in IMC drives is verified by simulations and experimental results.

• Bulletin of the Korean Chemical Society
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• v.35 no.7
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• pp.2093-2096
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• 2014

2H-azirine, a less known acetonitrile isomer, is observed in matrix IR spectra from the precursor exposed to radiation from laser ablation of transition-metals. Its vibrational characteristics confirm the previous results, and those for the deuterated and $^{13}C$ substituted isotopomers are also newly reported. The weak absorptions are traced to the low production yield due to its high energy and low extinction constants. IRC computations reveal smooth inter-conversion between 2H-azirine and $CH_2NCH$, providing a rationale for the observed variation of their relative contents during photolysis.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2004.10a
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• pp.407-411
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• 2004

Ohmic heating occurs when an electric current is passes through food, resulting in a temperature rise in the product due to the conversion of the electric energy into heat. The time spent in the thawing is critical for product sterility and quality. The objective of this study is to conduct numerical modelling between the effect of ohmic thawing intensity on PTT(phase transition time) at constant concentration and the effect of matrix concentrations on PTT at constant voltage condition. the stronger ohmic thawing intensity resulted in decreasing the PTT. High ohmic intensity causes short PTT. And the higher gelatin concentration, the faster increment of PTT. A numerical modeling was executed to predict the PTT influenced by the power intensity using exponential regression and the PTT influenced by gelatin concentration using logarithmic regression. Therefore, from this numerical model of gelatin matrix, it is possible to estimate exact values extensively.

• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3274-3278
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• 2013

$CF_2Cl{\cdots}Cl$, an elusive photo-isomer of $CF_2Cl_2$, has been observed in matrix IR spectra from the precursors exposed to radiation from laser ablation of transition-metals. Other plausible products, $CFCl_2{\cdots}F$ and $FClC{\cdots}F-Cl$ are not detected due to their considerably higher energies. Parallel to its previously reported analogues, the C-X bonds are considerably stronger than those of the reactant, and particularly the Cl atom that is weakly bound to the residual Cl atom forms an unusually strong carbon-halogen bond. NBO analysis reveals that the C-Cl bond is a true double bond, and the weak $Cl{\cdots}Cl$ bond is largely ionic, $F_2C=Cl^{\delta+}{\cdots}Cl^{\delta-}$. IRC computation reproduces smooth inter-conversion between the reactant and product, and the transition state is energetically close to the product, consistent with its prompt disappearance in the early stage of photolysis.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.243-246
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• 1998

This paper presents a 6-bit self-calibrated D/A converter designed with current cell matrix structure. This structure is based on the current-cell matrix configuration using a regulated gate cascode current cell with 3-way switch. using from CMOS process and 5V power supply, the simulated conversion rate is 45.78MHz and the average mismatching properties among current sources are reduced to 0.02% and 0.005%, respectively when 1% and 0.5% errors of current sources are considered.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2001.11a
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• pp.146-150
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• 2001

Microwave model and high-frequency measurement of the ACF flip-chip interconnection was investigated using a microwave network analysis. S-parameters of on-chip and substrate were separately measured in the frequency range of 200 MHz to 20 GHz using a microwave network analyzer HP8510 and cascade probe. And the cascade transmission matrix conversion was performed. The same measurements and conversion techniques were conducted on the assembled test chip and substrate at the same frequency range. Then impedance values in ACF flip-chip interconnection were extracted from cascade transmission matrix. ACF flip chip interconnection has only below 0.1nH, and very stable up to 13 GHz. Over the 13 GHz, there was significant loss because of epoxy capacitance of ACF. However, the addition of SiO$_2$filler to the ACF lowered the dielectric constant of the ACF materials resulting in an increase of resonance frequency up to 15 GHz. High frequency behavior of metal Au stud bumps was investigated. The resonance frequency of the metal stud bump interconnects is higher than that of ACF flip-chip interconnects and is not observed at the microwave frequency band. The extracted model parameters of adhesive flip chip interconnects were analyzed with the considerations of the characteristics of material and the design guideline of ACA flip chip for high frequency applications was provided.

• Journal of the Korean Institute of Telematics and Electronics
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• v.16 no.4
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• pp.1-12
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• 1979

This article is a sequel to " Korean Character Processing: Part I. Theoretical Foundation " and deals with the practical and historical aspects of the same subject. We discuss , in the first half, the functional design of Korean I/O terminals, Korean character generators based on the conversion algorithm and dot matrix fonts, input keyboard configuration ( trade -offs between a key set and the number of key -strokes ), and the conditions to be considered for binary code design. The second half of the article is devoted to the history of Korean Character processing which is seen from the personal viewpoints. The recorded works are classified into 4 groups according to their maj or contents. Then we bring up each problematic issue to give a critical review of articles . Issues related to output (conversion process) and input ( character recognition) are separated. The bibliography is given in a chronological order.cal order.