• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.43 no.9
• /
• pp.781-786
• /
• 2015

An aeroelastic stability can be degraded due to an aeroelastic modeling error and a structural uncertainty. Therefore it is necessary to predict the aeroelastic stability boundary considering an aeroelastic modeling error and a structural uncertainty. Robust aeroelastic analysis was proposed to predict the aeroelastic stability boundary considering these error and uncertainty. In the present study, the robust aeroelastic modeling and analysis were performed by using the ${\mu}$ analysis technique and the aeroelastic model of the control fin with modal approach and MSA. The computer program for the robust aeroelastic analysis was developed and verified by comparing its results with those of conventional aeroelastic analysis methods.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.8 no.6
• /
• pp.1166-1174
• /
• 2004

In this paper, a design of RISC-based transmission wrapper processor for TCP/IP protocol stack is described. The processor consists of input and output buffer memory with dual bank structure, 32-bit RISC microprocessor core, DMA unit with on-the-fly checksum capability, and memory module. To handle the various modes of TCP/IP protocol, hardware-software codesign approach based on RISC processor is used rather than the conventional state machine design. To eliminate large delay time due to sequential executions of data transfer and checksum operation, DMA module which can execute the checksum operation along with data transfer operation is adopted. The designed processor exclusive of variable-size input/output buffer consists of about 23,700 gates and its maximum operating frequency is about 167MHz under 0.35${\mu}m$ CMOS technology.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.06a
• /
• pp.154-154
• /
• 2008

Although the screen printing technology using photosensitive carbon nanotube (CNT) paste has many advantages such as low cost, simple process, uniform emission, and capability of mass production, the CNT paste needs to be improved further in CNT dispersion, printability, adhesion, electrical conductivity, population of CNT emitters, etc. Ball milling has been frequently employed to prepare the CNT paste as ball milling can mix its ingredients very well and easily cut the long, entangled CNTs. This study carried out a parametric approach to fabricating the CNT paste in terms of low-energy ball milling and a paste composition. Field emission properties of the CNT paste was characterized with CNT dispersion and electrical conductivity which were measured by a UV-Vis spectrophotometer and a 4-point probe method, respectively. Main variables in formulating the CNT paste include a length of milling time, and amounts of CNTs and conductive inorganic fillers. In particular, we varied not only the contents of conductive fillers but also used two different sizes of filler particles of ${\mu}m$ and nm ranges. Among many variations of conductive fillers, the best field emission characteristics occurred at the 5 wt% fillers with the mixing ratio of 3:1 for ${\mu}m$-and nm-sizes. The amount and size of fillers has a great effect on the morphology, processing stability, and field emission characteristics of CNT emitter dots. The addition a small amount of nm-size fillers considerably improved the field emission characteristics of the photosensitive CNT paste.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.1
• /
• pp.137-144
• /
• 2009

In this study, quantitative and pattern recognition analyses for the quality evaluation of Herba Epimedii using HPLC was developed. For quantitative analysis, five major bioactive constituents, hyperin, epimedin A, epimedin B, epimedin C, and icariin were determined. Analysis was carried out on Capcell pak $C_{18}$ column ($250{\time}4.6$ mm, 5 ${\mu}m$) with a mobile phase of mixture of acetonitrile and 0.1% formic acid, using UV detection at 270 nm. The linear behavior was observed over the investigated concentration range (2-50 ${\mu}g/mL;\;r_2\;>$ 0.99) for all analytes. The intraand inter-day precisions were lower than 4.3% (as a relative standard deviation, RSD) and accuracies between 95.1% and 104.4%. The HPLC analytical method for pattern recognition analysis was validated by repeated analysis of one reference sample. The RSD of intra- and inter-day variation of relative retention time (RRT) and relative peak area (RPA) of the 12 selected common peaks were below 0.8% and 4.7%, respectively. The developed methods were applied to analysis of twenty Herba Epimedii extract samples. Contents of hyperin, epimedin A, epimedin B, epimedin C, and icariin were calculated to be 0$\sim$0.79, 0.69$\sim$1.91, 0.93$\sim$9.58, 0.65$\sim$3.05, and 2.43$\sim$11.8 mg/g dried plant. Principal component analysis (PCA) showed that most samples were clustered together with the reference samples but several apart from the main cluster in the PC score plot, indicating differences in overall chemical composition between two clusters. The present study suggests that quantitative determination of marker compounds combined with pattern-recognition method can provide a comprehensive approach for the quality assessment of herbal medicines.

• Journal of Life Science
• /
• v.21 no.9
• /
• pp.1323-1328
• /
• 2011

We herein report the development of an agarose-gel-immobilized recombinant bacterial biosensor simple system for the field monitoring of phenolic compounds. Escherichia coli cells harboring the pLZCapR plasmid, which was previously designed to express the ${\beta}$-galactosidase reporter gene in the presence of phenolic compounds, were co-immobilized with a substrate [chlorophenol red ${\beta}$-galactopyranoside (CPRG) in agarose gel, and dispensed to the wells of a 96-well plate. Field samples were added to the wells and color development was monitored. In the presence of 5 ${\mu}M$ to 10 mM of phenol, the biosensor developed a red (representing hydrolysis of CPRG) color. Other phenolic compounds were also detected by this immobilized system, with the pattern resembling that previously reported for the corresponding non-immobilized biosensor. The immobilized cells showed optimum activity when the gel was simultaneously supplemented with 6% dimethyl formamide (DMF), 0.1% SDS and 10 mM $CaCl_2$. The immobilized biosensor described herein does not require the addition of a substrate or the use of unwieldy instruments or sample pretreatments that could complicate field studies.

• Journal of Environmental Science International
• /
• v.12 no.11
• /
• pp.1167-1171
• /
• 2003

Polycyclic aromatic hydrocarbons (PAHs) are an important group of organic contaminants present in sewage sludge, due to their persistence, toxic, bioaccumulative and long range transfer. These characters make themselves as Persistent Organic Pollutants(POPs) in Long Range Transboundary Air Pollutions convention(LRTAP) of Europe. A method of the gas chromatographicmass spectrometric (GCMS) determination of PAHs present in sewage sludge was developed and applied to analyzed samples from five sewerage treatment plants (SWTPs), having different treatment types. PAHs were extracted from freeze-dried samples by toluene 16 hours in a soxhlet extraction system. The sludge extracts were cleaned-up by an activated silica gel column chromatography. The sum of the 16 US Environmental Protection Agency PAHs sewage sludge samples varied from 2.44 to 4.82 $\mu\textrm{g}$/g. Concentration of emission carcinogen PAHs(PAHcarc), such as Benzo(a)anthracene, Benzo(b)f1uoranthene, Benzo(k)f1uoranthene, Benzo(a)pyrene, Dibenzo(a,h)anthracene and Indeno( 1,2,3-cd)pyrene ranged from 0.62 to 1.03 $\mu\textrm{g}$/g. The total amount of PAHs emission from sewage sludge in Korea was calculated as a top-down approach. PAHs and $\Sigma$PAHcarc from sewage treatment plants had emitted to environment by several pathway. The highest amount of emission to the environment was remarked in the ocean dumping(PAHs and $\Sigma$PAHcarc emissions were 1155.95 kg/year and 5040.32 kg/year, respectively).

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.8 no.2
• /
• pp.449-455
• /
• 2004

This paper presents a novel defect detection method for one chip RF front end with fault detection circuits using input matching measurement. We present a BIST circuit using 40.25{\mu}m$ CMOS technology. We monitor the input transient voltage of the RF front end to differentiate faulty and fault-free RF front end. Catastrophic as well as parametric variation fault models are used to simulate the faulty response of the RF front end. This technique has several advantages with respect to the standard approach based on current test stimulus and frequency domain measurement. Because DUT and fault detection circuits are implemented in the same chip, this test technique only requires use of digital voltmeter (RMS meter) and RF voltage source generator for simpleand inexpensive testing.

• The KIPS Transactions:PartB
• /
• v.15B no.3
• /
• pp.189-196
• /
• 2008

In this paper, a CMOS digital image sensor, which consists of A/D conversion, motion estimation circuits, and an attention module for ROI (Region of Interest) detection is presented. The functions of A/D conversion and motion estimation are implemented by $0.6{\mu}m$ CMOS processing circuit as hardware, and the attention module is implemented outside the circuit as software currently. Attention modules are taken to improve limited applications of the smart image sensor. The current smart image sensor responses to the changes of intensity, and uses the integration time to estimate motion. Therefore it is limited in its applications. To make up for inherent property of the sensor from circuit design and extend its applications we decide to introduce perception solutions to the image sensor. Attention modules for still and moving images are employed to achieve such purposes. The suggested approach makes the smart image sensor available with additional functions for such cases that motion estimation or intensity changes are not observed. Experimental result shows the usefulness and extension of the image sensor.

• Proceedings of the KIEE Conference
• /
• 2002.11a
• /
• pp.260-262
• /
• 2002

The determination of DNA hybridization can apply the molecular biology research. clinic diagnostics. bioengineering, environment monitoring, food science and other application area. So, The determination of hybridization is very important for the improvement of DNA detection system. In this study, we report the characterization of the DNA hybridization by the electricalchemical methods. The probe oligonucleotide was used to determine the amount of target oligonucleotide in solution using Methylen Blue(MB) as the electrochemical indicators. The cathodic peak currents($I_{peak}$) of MB were linearly related to the concentration of the target oligonucleotide sequence in the range $1[{\mu}M]{\sim}0.1[{\mu}M]$. The detection limit of this approach was 0.01[nM]. As a result, the match oligonucleotide(CR-1) was most stable state and the peak of redox current measured by DNA hybridization detection sensors by using electrochemical method seem to be similar to 1-mer terminal mismatch oligonucleotide(MR-3). The MR-2, MR-3, MR-22 and MR-33 have each mismatching sequence of central and terminal. With this set the role of point mutations was to be investigated. Terminal mismatch oligonucleotide (MR-3, 33) is shown more stable state than central mismatch oligonucleotide(MR-2, 22). And 1-mer mismatch oligonucleotide(MR-2 or 3) is shown more stable state than 2-mer mismatch oligonucleotide(MR-22 or 33).

• Journal of Applied Biological Chemistry
• /
• v.62 no.2
• /
• pp.129-135
• /
• 2019

Salvia miltiorrhiza Radix is cultivated in Korea and China and is traditionally used to treat cardiovascular diseases. In this study, we developed and validated a quantitative analysis method for S. miltiorrhiza Radix using high-performance liquid chromatography (HPLC). Identification was performed using ultra performance liquid chromatography-tandem mass spectrometry. For quantitative analysis, we used seven marker compounds. Separation conditions for HPLC were optimized using an ODS column with gradient conditions of 1% formic acid in distilled water and 1% formic acid in acetonitrile, with a flow rate of 0.8 mL/min and a detection wavelength of 280 nm. This method showed good linearity ($R^2=0.9998$), precision (relative standard deviation ${\leq}3.3%$), accuracy (recovery of 94.16-102.89%), limit of detection ($7.53{\mu}g/mL$), and limit of quantification ($23.71{\mu}g/mL$). This approach successfully quantified marker compounds in S. miltiorrhiza Radix. The individual marker compounds were identified by comparing the molecular masses and retention times with does standard compounds. Marker compound contents of S. miltiorrhiza Radix were investigated with different cultivation regions. Seven marker compounds were detected and quantified in all samples. Among them, salvianolic acid B showed the highest contents and it ranged from 4.13 to 7.15%. The salvianolic acid B content (7.15%) of marker compound was the highest in Bonghwa, and the tanshinone IIA content (1.90%) was the highest in Pohang. The results of marker compounds and developed method were intended to provide a favorable reference for the study of S. miltiorrhiza Radix from different regions of Korea.