• Journal of Life Science
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• v.22 no.4
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• pp.466-471
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• 2012

Sixty individuals of the scallop $Patinopecten$ $yessoensis$ (Genus Pecten) were sampled to examine the genetic diversity and population structure of this species. Random amplified polymorphic DNA (RAPD) identified 109 genotypes and produced 79 polymorphic loci (72.8%). Total genetic diversity values ($H_T$) and interlocus variation in the within-population genetic diversity ($H_S$) were 0.254 and 0.178, respectively. On a per-locus basis, the proportion of total genetic variation due to differences among populations ($G_{ST}$) was 0.299. This indicated that about 70.1% of the total variation was within populations. The unique loci and bands of $P.$ $yessoensis$ were shown in only one population among the three countries. RAPD markers were very effective in classifying the natural population levels of $P.$ $yessoensis$ in Korea, China, and Japan. In addition, insights into the relative gene diversity among and within populations of $P.$ $yessoensis$ would be useful in breeding and for the development of strategies for animal genetic resources.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.311-311
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• 2016

최근 고성능 디스플레이 개발이 요구되면서 기존 비정질 실리콘(a-Si)을 대체할 산화물 반도체에 대한 연구 관심이 급증하고 있다. 여러 종류의 산화물 반도체 중 a-IGZO (amorphous indium-gallium-zinc oxide)가 높은 전계효과 이동도, 저온 공정, 넓은 밴드갭으로 인한 투명성 등의 장점을 가지며 가장 연구가 활발하게 보고되고 있다. 기존에는 SG(단일 게이트) TFT가 주로 제작 되었지만 본 연구에서는 DG(이중 게이트) 구조를 적용하여 고성능의 a-IGZO 기반 박막 트랜지스터(TFT)를 구현하였다. SG mode에서는 하나의 게이트가 채널 전체 영역을 제어하지만, double gate mode에서는 상, 하부 두 개의 게이트가 동시에 채널 영역을 제어하기 때문에 채널층의 형성이 빠르게 이루어지고, 이는 TFT 스위칭 속도를 향상시킨다. 또한, 상호 모듈레이션 효과로 인해 S.S(subthreshold swing)값이 낮아질 뿐만 아니라, 상(TG), 하부 게이트(BG) 절연막의 계면 산란 현상이 줄어들기 때문에 이동도가 향상되고 누설전류 감소 및 안정성이 향상되는 효과를 얻을 수 있다. Dual gate mode로 동작을 시키면, TG(BG)에는 일정한 positive(or negative)전압을 인가하면서 BG(TG)에 전압을 가해주게 된다. 이 때, 소자의 채널층은 depletion(or enhancement) mode로 동작하여 다른 전기적인 특성에는 영향을 미치지 않으면서 문턱 전압을 쉽게 조절 할 수 있는 장점도 있다. 제작된 소자는 p-type bulk silicon 위에 thermal SiO2 산화막이 100 nm 형성된 기판을 사용하였다. 표준 RCA 클리닝을 진행한 후 BG 형성을 위해 150 nm 두께의 ITO를 증착하고, BG 절연막으로 두께의 SiO2를 300 nm 증착하였다. 이 후, 채널층 형성을 위하여 50 nm 두께의 a-IGZO를 증착하였고, 소스/드레인(S/D) 전극은 BG와 동일한 조건으로 ITO 100 nm를 증착하였다. TG 절연막은 BG 절연막과 동일한 조건에서 SiO2를 50 nm 증착하였다. TG는 S/D 증착 조건과 동일한 조건에서, 150 nm 두께로 증착 하였다. 전극 물질과, 절연막 물질은 모두 RF magnetron sputter를 이용하여 증착되었고, 또한 모든 patterning 과정은 표준 photolithography, wet etching, lift-off 공정을 통하여 이루어졌다. 후속 열처리 공정으로 퍼니스에서 질소 가스 분위기, $300^{\circ}C$ 온도에서 30 분 동안 진행하였다. 결과적으로 $9.06cm2/V{\cdot}s$, 255.7 mV/dec, $1.8{\times}106$의 전계효과 이동도, S.S, on-off ratio값을 갖는 SG와 비교하여 double gate mode에서는 $51.3cm2/V{\cdot}s$, 110.7 mV/dec, $3.2{\times}108$의 값을 나타내며 훌륭한 전기적 특성을 보였고, dual gate mode에서는 약 5.22의 coupling ratio를 나타내었다. 따라서 산화물 반도체 a-IGZO TFT의 이중게이트 구조는 우수한 전기적 특성을 나타내며 차세대 디스플레이 시장에서 훌륭한 역할을 할 것으로 기대된다.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.3
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• pp.185-191
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• 2005

Photo-reactive $TiO_2$ thin films on soda-lime-silica slide glass were prepared by spin coating technique with a Ti-naphthenate precursor. Optical, structural and photo-catalytic properties of the films after annealing at $500^{\circ}C{\sim}600^{\circ}C$ were evaluated. As increase with annealing temperature, absorption bands and total transmittance of the films showing an average transmittance (about 80%) at visible spectra range were shifted to UV spectra range and slightly decreased. Refractive index and thickness of the films were increased from 2.16 to 2.63 and decreased from 484 nm to 439 nm, respectively, with increase of annealing temperature. Anatase phase was visible at all annealing temperature. More rougher surface structure was obtained at $600^{\circ}C$ than those of films annealed at $500^{\circ}C$ and $550^{\circ}C$. The hydrophilic conversion was found within 45 min by UV stimulation and optical activation was UVC>UVA>UVB at the case of $500^{\circ}C{\sim}550^{\circ}C$ and UVA>UVC>UVB at the annealing temperature of $600^{\circ}C$. The lowest initial contact angle was obtained at $600^{\circ}C$.

• Fashion & Textile Research Journal
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• v.8 no.4
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• pp.471-475
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• 2006

The summary of a study of efficacy of Rose essential oil and Lavender essential oil against skin-inflammation caused to surfactant is as follows. As a result of protein analysis, although Rose essential oil and Lavender essential oil stimulates skin, there is no much alteration of protein. The alteration of protein's bend to be under part of 43Kd is appeared in the group treated Rose essential oil and Lavender essential oil. The stratum of the group treated by surfactant is more, the stratum of the group treated by surfactant is more thick. As the observed result of alteration of basal layer, it is seen that the group treated Rose essential oil and Lavender essential oil takes the shape of cell layer constant, and the group treated Rose essential oil is made the basal cell layer of normal structure than that of Lavender essential oil. As the observed result of alteration of Mast cell group treated by Rose essential oil and Lavender essential oil for 3 weeks Luna's stain(${\times}20$), (${\times}100$), it is observed that the damaged group treated by Lavender essential oil is numerous in alteration of mast cell's number, and Mast cell's size is larger than the damaged group.

• Journal of the Korean Society of Radiology
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• v.12 no.4
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• pp.451-457
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• 2018

Luminescence properties of $NaCa(PO_3)_3$ doped with $Tb^{3+}$ ions are investigated by optical and laser excitation spectroscopy. The phosphors were prepared by solidstate reaction method The X-ray diffraction(XRD) was used to analyze the crystal structure and the crystallinity of the samples. The excitation and emission spectra and decay curve of $NaCa(PO_3)_3:Tb^{3+}$(0.01 ~ 30mol%) were measured at room temperature. The f - d band of $Tb^{3+}$ is observed in the excitation spectra of $NaCa(PO_3)_3:Tb^{3+}$ in the wave length region 205 ~ 245 nm. Strong emission lines due to the $^5D_4{\rightarrow}^7F_J$ transition and weak emission lines due to the $^5D_4{\rightarrow}^7F_J$ transition are observed in the emission spectra of $NaCa(PO_3)_3:Tb^{3+}$. The energy transfer and cross relaxation between $Tb^{3+}$ ions are discussed in $NaCa(PO_3)_3:Tb^{3+}$ in the emission spectra and life time.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.334-341
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• 2016

In this paper, the study of a waveguide aperture-coupled feed-structured antenna has been conducted for the purpose of applying it to a wireless back-haul system sufficient for high-capacity gigabits-per-second data rates. For this study, a $32{\times}32$ waveguide slot sub-array antenna with a corporate-feed structure was designed and produced. Also, this antenna is used at 57 GHz to 66 GHz in the V-band. The construction of the antenna is a laminated form with radiating parts (outer groove and slot, cavity), a coupled aperture, and feeds in each. The antenna was designed with HFSS, which is based on 3D-FEM, produced with aluminum processed by a precision-controlled milling machine, and assembled after a silver-plating process. The measurement result from analysis of the characteristics of the antenna shows that return loss is less than -12 dB, VSWR < 2.0, and a wide bandwidth ranges up to 16%. An overall first side lobe level is less than -12.3 dB, and a 3 dB beam width is narrow at about $1.85^{\circ}$. Also, antenna gain is 38.5 dBi, offering high efficiency exceeding 90%.

• Journal of the Microelectronics and Packaging Society
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• v.22 no.1
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• pp.55-61
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• 2015

Stretchable electrode materials are focused to apply to flexible device such as e-skin and wearable computer. Used as a flexible electrode, increase in electrical resistance should be minimalized under physical strain as bend, stretch and twist. Carbon black is one of candidates, for it has many advantages of low cost, simple processing, and especially reduction in resistivity with stretching. However electrical conductivity of carbon black is relatively low to be used for electrodes. Instead graphene is one of the promising electronic materials which have great electrical conductivity and flexibility. So it is expected that graphene added carbon black may be proper to be used for stretchable electrode. In this study, under stretching electrical property of graphene added carbon black composite electrode was investigated. Mechanical stretching induced cracks in electrode which means breakage of conductive path. However stretching induced aligned graphene enhanced connectivity of carbon fillers and maintained conductive network. Above all, electronic structure of carbon electrode was changed to conduct electrons effectively under stretching by adding graphene. In conclusion, an addition of graphene gives potential of carbon black composite as a stretchable electrode.

• KSBB Journal
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• v.14 no.6
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• pp.724-730
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• 1999

Characteristics and enzyme activity comparison was made between urokinase isolated from urine and pro-urokinase separated from CHO(Chinese Hamster Ovary) cell culture broth. Both of purified urokinase and pro-urokinase resulted 54Kd single band in electrophoresis. Urokinase which was proved as a single molecule by gel filtration showed two separated 33Kd and 21Kd bands by 2-mercaptoethanol reduction. Isoelectric forcusing resulted same pl value of 8.6 for both of them. N-terminal amino acid sequence of urokinase after 159th Ile was Ile-Gly-Gly-Glu-Phe-Thr-Thr-Ile-Glu which was different from another N-terminal sequence of Ser-Asn-Glu-Leu-His-Gln-Val-Pro-Ser-Asn. Thrombolytic activities of both of them were propotional to the enzyme concentration. Urokinase showed thrombolytic activities in an short period of reaction time. Pro-urokinase, however, showed high thrombolytic activity for 2 hours or longer period of reaction time.

• Journal of Life Science
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• v.20 no.10
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• pp.1538-1543
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• 2010

This study was conducted to examine the genetic diversity and population structure of 17 Brassica juncea populations in Korea. The technique of random amplified polymorphic DNA (RAPD) produced 60 polymorphic loci and 18 monomorphic loci. In a simple measure of intraspecies variability by the percentage of polymorphic bands, the Jindo population of Cheonnam showed the highest (29.5%). The cultivar exhibited the lowest variation (12.8%). Mean number of alleles per locus (A) and the effective number of alleles per locus ($A_E$) were 1.221 and 1.167, respectively. As the typical populations of this species were small, isolated, and patchily distributed in their natural populations, they maintained a low level of genetic diversity of fourteen primers. On a per locus basis, total genetic diversity values ($H_T$) and interlocus variation in the within-population genetic diversity ($H_S$) were 0.347 and 0.141, respectively. On a per-locus basis, the proportion of total genetic variation due to differences among populations ($G_{ST}$) was 0.589. This indicated that about 58.9% of the total variation was among populations. The estimate of gene flow, based on $G_{ST}$, was very low among Korean populations of B. juncea ($N_m$=0.617). These results suggest that the geological distance dispersal of wild B. juncea is the best event. RAPD markers are very effective in classifying natural population levels of B. juncea in Korea.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.9 s.339
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• pp.9-18
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• 2005

To make high-performance, low-power transistors beyond the technology node of 60 nm complementary metal-oxide-semiconductor field-effect transistors(C-MOSFETs) possible, the effect of electron mobility of the thickness of strained Si grown on a relaxed SiGe/SiO2/Si was investigated from the viewpoint of mobility enhancement via two approaches. First the parameters for the inter-valley phonon scattering model were optimized. Second, theoretical calculation of the electronic states of the two-fold and four-fold valleys in the strained Si inversion layer were performed, including such characteristics as the energy band diagrams, electron populations, electron concentrations, phonon scattering rate, and phonon-limited electron mobility. The electron mobility in an silicon germanium on insulator(SGOI) n-MOSFET was observed to be about 1.5 to 1.7 times higher than that of a conventional silicon on insulator(SOI) n-MOSFET over the whole range of Si thickness in the SOI structure. This trend was good consistent with our experimental results. In Particular, it was observed that when the strained Si thickness was decreased below 10 nm, the phonon-limited electron mobility in an SGOI n-MOSFT with a Si channel thickness of less than 6 nm differed significantly from that of the conventional SOI n-MOSFET. It can be attributed this difference that some electrons in the strained SGOI n-MOSFET inversion layer tunnelled into the SiGe layer, whereas carrier confinement occurred in the conventional SOI n-MOSFET. In addition, we confirmed that in the Si thickness range of from 10 nm to 3 nm the Phonon-limited electron mobility in an SGOI n-MOSFET was governed by the inter-valley Phonon scattering rate. This result indicates that a fully depleted C-MOSFET with a channel length of less than 15 m should be fabricated on an strained Si SGOI structure in order to obtain a higher drain current.