• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.735-736
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• 1998

Reduction of hot carrier degradation in MOS devices has been one of the most serious concerns for MOS-ULSIs. In this paper, three types of LDD structure for suppression of hot carrier degradation, such as spacer-induced degradation and decrease of performance due to increase of series resistance will be investigated. LDD-nMOSFETs used in this study had three different drain structure. (1) conventional ${\underline{S}}urface$ type ${\underline{L}}DD$(SL), (2) ${\underline{B}}uried$ type ${\underline{L}}DD$(BL), (3) ${\underline{S}}urface$urface ${\underline{I}}mplantation$ type LDD(SI). As a result, the surface implantation type LDD structure showed that improved hot carrier lifetime to comparison with conventional surface and buried type LDD structure.

• Journal of agriculture & life science
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• v.46 no.1
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• pp.71-81
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• 2012

This study was conducted to get basic information about making windbreak forest around Saemanguem reclaimed lands by analyzing the vegetation structure of 8 windbreak forests along the west coast of Korea and considering the methods of structural improvement. The total plants existing in the study areas were 25 families 40genus 43 species, and every tree layer consisted of only one tree species, Pinus thunbergii. There were 2 windbreak stands consisted of a species, and 2 consisted of multiple layer with a species. While, 4 windbreak stands consist of various species with several species. To make ecological system and functions of windbreak forests stabler, TL, STL and SL should be together in the vertical point, moreover, TL should be appeared at the in side and SL should be planted at the out side in the horizontal point. It is considered that mixed stand forest might be suitable for increasing the windbreak forest's functions and decreasing damage caused by disease and insects.

• Korean Journal of Ichthyology
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• v.19 no.4
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• pp.371-377
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• 2007

The passive integrated transponder (PIT) telemetry is a useful method for investigating fish population dynamics, community structure and migration. It can be applied for small fishes (TL<100 mm) because of its tiny size and light weight. The survival rate of PIT tag was investigated on 4 small size cyprindae fish species, Carassius gibelio langsdorfi (n=34, standard length; $91.9{\pm}0.9mm$, body weight; $21.2{\pm}0.9g$), Hypophthalmichthys molitrix (n=16, SL; $75.1{\pm}0.9mm$, BW; $6.0{\pm}0.2g$), Pseudorasbora parva (n=30, SL; $51.4{\pm}1.1mm$, BW; $2.7{\pm}0.2g$) and Phoxinus phoxinus (n=37, SL; $70.6{\pm}1.4mm$, BW; $8.2{\pm}0.5g$) under age 1 for applicability and effectiveness. We used three type tags including a small (length 11.0 mm, diameter 2.1 mm, weight 0.088 g), middle (20 mm, 3.5 mm, 0.102 g), large (30 mm, 3.5 mm, 0.298 g) size. After 30 days of tag insertion, survival rate of 117 individuals were 58.1% (large tag, 50.0%; middle tag, 57.5%; small tag, 61.4%). Survival rates varied between three types of tags because the abdominal cavity of each individual was different size. The death was due to surgical damage. If we apply tagging systems on field research of the Korean freshwater fish, the PIT tag will be effective method for analyzing fish ecology.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.2
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• pp.123-130
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• 2008

A 3D structure production method for microstereolithography is a useful way that produces complex structures with flexible processes and low cost. Several UV curable resins were blended and the optimal resin for micro-lens fabricate was selected through viscosity, workability and transmission tests. It consists of 1, 6 - Hexanediol diacrylate with 15 Apha and Isobornyl acrylate for reducing some shrinkage. When fabricating a micro-lens array on large surface, some distortion of shape occurred because of the surface tension between cured part. To overcome this problem, the optimal processing conditions were derived from considering amount of the resin and surface tension. Large surface Micro-lens array, which are a type of elliptical convex and consist of 18,000 micro-lens in the range of 2cm*2cm were fabricated. The focal length to the X-axis and Y-axis were calculated. To verify the performance, measure an energy distribution of transmitted light from the Large surface Micro-lens array.

• JSTS:Journal of Semiconductor Technology and Science
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• v.8 no.4
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• pp.289-294
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• 2008

A 77 GHz 3-stage low noise amplifier (LNA) employing one common source and two cascode stages is developed using $0.13{\mu}m$ CMOS process. To compensate for the low gain which is caused by lossy silicon substrate and parasitic element of CMOS transistor, positive feedback technique using parasitic inductance of bypass capacitor is adopted to cascode stages. The developed LNA shows gain of 7.2 dB, Sl1 of -16.5 dB and S22 of -19.8 dB at 77 GHz. The return loss bandwidth of LNA is 71.6 to 80.9 GHz (12%). The die size is as small as $0.7mm\times0.8mm$ by using bias line as inter-stage matching networks. This LNA shows possibility of 77 GHz automotive RADAR system using $0.13{\mu}m$ CMOS process, which has advantage in cost compared to sub-100 nm CMOS process.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.3
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• pp.194-204
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• 2015

Six study sites in Gumi, Goryeong in Gyeongbuk province and Naju in Jeonnam province were selected to investigate soil properties of poorly drained horizons in paddy soils. The horizons were re-established layers which were parent material layers originated from fluvial deposits. Topsoil layers were differentiated from piled parent materials while soil structure of the topsoil layer was massive with striated microstructure. Compaction at soil re-establishment and a lack of structure and aggregate development in these soils may cause the limitation of vertical water movement and result in poorly drained horizons. Soil samples were taken from paddy fields with top soils of sandy loam, silt loam and silty clay loam and re-established soils of coarse and fine texture. The samples were taken from each horizon for the analyses of soil chemical and mineral properties. Soils with re-established soils of coarse texture had greater amounts of sands from top soil texture distributions, while soils with fine texture had greater amounts of silts. Chemical properties of top soils were analyzed from rice cultivated soils at the time of re-establishments and one year after the re-establishments. The coarse texture of the re-established horizons decreased in EC values from 0.23 to $0.11(dS\;m^{-1})$, available phosphate values from 112 to $54(mg\;kg^{-1})$, and exchangeable Ca values from 6.6 to $4.9(cmol_c\;kg^{-1})$. On the other hand, soils with fine texture showed decrease only in pH and exchangeable Ca values. Especially, organic matter and available phosphate contents showed heterogeneous distributions from each horizon. This result may be caused by mixture of plough layer and subsurface layer during and consolidation. Hydraulic conductivity values were low at the boundaries of top soil and parent material layers except SL/coarse soil. Soil microstructure was massive structure without soil clods or pores and showed striated structure. Therefore, re-established paddy fields with fluvial deposits as parent material layers showed limited vertical movements of soil water because of occurrence of compacted layers and less-development of soil clods and aggregates.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.1
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• pp.63-71
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• 2004

The human skin is constantly exposed to environmental irritants such as ultraviolet, smoke, chemicals. Free radicals and reactive oxygen species (ROS) caused by these environmental facts play critical roles in cellular damage. These irritants are in themselves damaging to the skin structure but they also participate the immensely complex inflammatory reaction. The purpose of this study was to investigate the skin cell protective effect of Juniperus chinensis xylem extract on the UV and SLS-induced skin cell damages. We tested free radical and superoxide scavenging effect in vitro. We found that Juniperus chinensis xylem extracts had potent radical scavenging effect by 98％ at 100 $\mu\textrm{g}$/mL. Fluorometric assays of the proteolytic activities of matrix metalloproteinase-l(MMP-1, collagenase) were performed using fluorescent collagen substrates. UV A induced MMP-1 synthesis and activity were analyzed by enzyme-linked immunosorbent assay (ELISA) and gelatin-based zymography in skin fibroblasts. The extract of Juniperus chinensis showed strong inhibitory effect on MMP-1 activities by 97％ at 100 $\mu\textrm{g}$/mL and suppressed the UVA induced expression of MMP-1 by 79％ at 25 $\mu\textrm{g}$/mL. This extract also showed strong inhibition on MMP-2 activity in UVA irradiated fibroblast by zymography. We also examined anti-inflammatory effects by the determination test of proinflammatory cytokine, interleukin 6 in HaCaT keratinocytes. In this test Juniperus chinensis decreased expression of interleukin 6 about 30％. Expression of prostaglandin E$_2$, (PGE$_2$) after UVB irradiation was measured by competitive enzyme immunoassay (EIA) using PGE$_2$ monoclonal antibody. At the concentrations of 5-50 $\mu\textrm{g}$/mL of the extracts, the production of PGE$_2$ by HaCaT keratinocytes (24 hours after 10 mJ/$\textrm{cm}^2$ UVB irradiation) was significantly inhibited in culture supernatants (p〈0.05). The viability of cultured HaCaT keratinocytes was significantly reduced at the doses of above 10 mJ/$\textrm{cm}^2$ of UVB irradiation, but the presence of these extracts improved cell viability comparing to control after UVB irradiation. We also investigated the protective effect of this extract in sodium lauryl sulfate (SLS)-induced irritant skin reactions from 24 hour exposure. Twice a day application of the extract for reducing local inflammation in human skin was done. Irritant reactions were assessed by various aspects of skin condition, that is, erythema (skin color reflectance) and transepidermal water loss (TEWL). After 5 days the extract was found to reduce SLS-induced skin erythema and improve barrier regeneration when compared to untreated symmetrical test site. In conclusion, our results suggest that Juniperus chinensis can be effectively used for the prevention of UV and SLS-induced adverse skin reactions such as radical production, inflammation and skin cell damage.

• The Journal of Korean Academy of Prosthodontics
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• v.38 no.5
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• pp.704-723
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• 2000

This study was undertaken to evaluate the tensile bond strength of In-Ceram alumina core treat-ed by ion assisted reaction(IAR). Ion assisted reaction is a prospective surface modification technique without damage by a keV low energy ion beam irradiation in reactive gas environments or reactive ion itself. 120 In-Ceram specimens were fabricated according to manufacturer's directions and divided into six groups by surface treatment methods of In-Ceram alumina core. SD group(control group): sandblasting SL group: sandblasting + silane treatment SC group: sandblasting + Siloc treatment IAR I group: sandblasting + Ion assisted reaction with argon ion and oxygen gas IAR II group: sandblasting + Ion assisted reaction with oxygen ion and oxygen gas IAR III group: sandblasting + Ion assisted reaction with oxygen ion only For measuring of tensile bond strength, pairs of specimens within a group were bonded with Panavia 21 resin cement using special device secured that the film thickness was $80{\mu}m$. The results of tensile strength were statistically analyzed with the SPSS release version 8.0 programs. Physical change like surface roughness of In-Ceram alumina core treated by ion assistad reaction was evaluated by Contact Angle Measurement, Scanning Electron Microscopy, Atomic Force Microscopy; chemical surface change was evaluated by X-ray Photoelectron Spectroscopy. The results as follows: 1. In tensile bond strength, there were no statistically significant differences with SC group, IAR groups and SL group except control group(P<0.05). 2. Contact angle measurement showed that wettability of In-Ceram alumina core was enhanced after IAR treatment. 3. SEM and AFM showed that surface roughness of In-Ceram alumina core was not changed after IAR treatment. 4. XPS showed that IAR treatment of In-Ceram alumina core was enabled to create a new functional layer. A keV IAR treatment of In-Ceram alumina core could enhanced tensile bond strength with resin cement. In the future, this ion assisted reaction may be used effectively in various dental materials as well as in In-Ceram to promote the bond strength to natural tooth structure.

• Journal of The Korean Astronomical Society
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• v.29 no.2
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• pp.245-253
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• 1996

We have analyzed infrared (IR) images of Jupiter which was observed at the McDonald Observatory, Texas, U.S.A., during the P/SHoemaker-LEvy 9 (SL9) impact period and about one week after the last impact. The IR images were obtained on the 2.7m telescope using a NICMOS array with filters to isolate the $1.5{\mu}m\;NH_3\; band,\;the\;2.3{\mu}m\;CH_4\;band,\;the\;2.12{\mu}m\;H_2\;S(0)$ pressure-induced absorption, and the continua at $1.58{\mu}m\;and\;2.0{\mu}m$ (short K-band). All images except those with the $1.58{\mu}m$ continuum filter show bright impact sites against the relatively dark Jovian disk near the impact latitude of about $45^{\circ}$ S. This implies that dusts originated from the impacts reflect the solar radiation at high altitudes before absorbed by stratospheric $CH_4,\;NH_3 \;or\;H_2$. The impact sites observed with the $2.3{\mu}m$ filter are conspicuously bright against a very dark background. The morphology of impact sites, G, L, and H at 2.3 and $2.12{\mu}m$ filters shows clearly an asymmetric structure toward the incident direction of the comet fragments, in agreement with the studies of visible impact images obtained with the Hubble Space Telescope. Comparisons of reflectances of G, L, and H sites with simple radiative transfer models suggest that optically thick dust layers were formed at high altitudes at which methane absorption attenuates incoming sunlight only by about $1\%$. The dust layers in these sites seem to form at about the same altitude regardless of the magnitude of the impacts, but they appear to descend gradually after the impacts. The dust layers have optical depths of 2-5, according to the models.

• Journal of the Korea Society of Computer and Information
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• v.19 no.12
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• pp.111-121
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• 2014

In this paper, we propose tree-based hybrid query tree architecture utilizing time slot. 4-Bit Pattern Slot Allocation(4-SL) has a 8-ary tree structure and when tag ID responses according to query of the reader, it applies a digital coding method, the Manchester code, in order to extract the location and the number of collided bits. Also, this algorithm can recognize multiple Tags by single query using 4 fixed time slots. The architecture allows the reader to identify 8 tags at the same time by responding 4 time slots utilizing the first bit($[prefix+1]^{th}$, F ${\in}$ {'0' or '1'}) and bit pattern from second ~ third bits($[prefix+2]^{th}{\sim}[prefix+3]^{th}$, $B_2{\in}$ {"00" or "11"}, $B_1{\in}$ {"01" or "10"}) in tag ID. we analyze worst case of the number of query nodes(prefix) in algorithm to extract delay time for recognizing multiple tags. The identification delay time of the proposed algorithm was based on the number of query-responses and query bits, and was calculated by each algorithm.