• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.338.2-338.2
• /
• 2016

Al doped ZnO (AZO) thin films were deposited on Si substrates with rod-shaped-surface by pulsed laser deposition method (PLD). Si-rods were prepared through chemical etching. To analyze the influence on the formation of the rod structure, samples with various chemical etching conditions such as AgNO3/HF ratio, etching time, and solution temperature were prepared. The morphology of Si-rod structures were examined by FE-SEM. Fig. 1 shows a typical structure of n-AZO/p-Si-rod juncions. The fabricated n-AZO/p-Si-rod devices exhibited p-n diode current-voltage characteristics. We compared the I-V characteristics of n-AZO/p-Si-rod devices with the samples without Si-rod structure.

• Korean Journal of Radiology
• /
• v.23 no.7
• /
• pp.752-762
• /
• 2022

Objective: To compare a deep learning-based reconstruction (DLR) algorithm for pediatric abdominopelvic computed tomography (CT) with filtered back projection (FBP) and iterative reconstruction (IR) algorithms. Materials and Methods: Post-contrast abdominopelvic CT scans obtained from 120 pediatric patients (mean age ± standard deviation, 8.7 ± 5.2 years; 60 males) between May 2020 and October 2020 were evaluated in this retrospective study. Images were reconstructed using FBP, a hybrid IR algorithm (ASiR-V) with blending factors of 50% and 100% (AV50 and AV100, respectively), and a DLR algorithm (TrueFidelity) with three strength levels (low, medium, and high). Noise power spectrum (NPS) and edge rise distance (ERD) were used to evaluate noise characteristics and spatial resolution, respectively. Image noise, edge definition, overall image quality, lesion detectability and conspicuity, and artifacts were qualitatively scored by two pediatric radiologists, and the scores of the two reviewers were averaged. A repeated-measures analysis of variance followed by the Bonferroni post-hoc test was used to compare NPS and ERD among the six reconstruction methods. The Friedman rank sum test followed by the Nemenyi-Wilcoxon-Wilcox all-pairs test was used to compare the results of the qualitative visual analysis among the six reconstruction methods. Results: The NPS noise magnitude of AV100 was significantly lower than that of the DLR, whereas the NPS peak of AV100 was significantly higher than that of the high- and medium-strength DLR (p < 0.001). The NPS average spatial frequencies were higher for DLR than for ASiR-V (p < 0.001). ERD was shorter with DLR than with ASiR-V and FBP (p < 0.001). Qualitative visual analysis revealed better overall image quality with high-strength DLR than with ASiR-V (p < 0.001). Conclusion: For pediatric abdominopelvic CT, the DLR algorithm may provide improved noise characteristics and better spatial resolution than the hybrid IR algorithm.

• Resources Recycling
• /
• v.4 no.3
• /
• pp.32-39
• /
• 1995

Thc purpose of this study is to develop the efficient process for recovering vanadium and nickel from the incineralionash of the oil fly ash. In this paper, the physical and chemical properties of the incineration ash was examined, and theleaching characteristics of the incineration ash were investigated by water leaching and sulEuric acid leaching tcsls. The incinerationash of oil fly ash was mainly consisted of oxldes such as V,09, V,O,, NaVO,, Ni,(VO,)Z, Fe,O,, CaSO,, SiO,.Thc waler leaching showed low extraction of metallic components, while the sulfunc acid lcaching with high temperahlreand pressure increased the extraction of vanadium and nickcl considerably. For instance, the exlraction rates of the metalllccomponents on the sulfuric acid leaching were 99% for V and 45% for Ni at 90$^{\circ}$C with pH 0.5 H,SO,, and were86% for V and 75% far Ni at ZOO"C(64 psi) with pH 1.0 H-SO,. with pH 1.0 H-SO,.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.33 no.5
• /
• pp.448-454
• /
• 2000

This study was to examine the physicochemical characteristics of coagulation reaction between ignited oyster shell powder (IOSP) and red tide organisms (RTO), and its feasibility, in developing a technology for the removal of RTO bloom in coastal sea,IOSP was made from oyster shell and its physicochemical characteristics were examined for particle size distribution, surface characteristic by scanning electron microscope, zeta potential, and alkalinity and pH variations in sea water. Two kinds of RTO that were used in this study, Cylindrotheca closterium and Skeletonema costatum, were sampled in Masan bay and were cultured in laboratory. Coagulation experiments were conducted using various c(Incentrations of IOSP, RTO, and a jar tester. The supernatant and RTO culture solution were analyzed for pH, alkalinity, RTO cell number, IOSP showed positive zeta potentials of $11.1{\~}50.1\;mV\;at\;pH\;6.2{\~}12.7$, A positive zeta potential of IOSP slowly decreased with decreasing pNa 4,0 to 2,0. When pNa reached zero, the zeta potential approached zero, When a pMg value was decreased, the positive zeta potential of IOSP increased until pMg 3.0 and decreased below pMg 3.0. IOSP showed 4.8 mV of positive zeta potential while RTO showed -9.2 mV of negative zeta potential in sea water. A positive-negative EDL (electrical double-layer) interaction occurred between $Mg(OH)_2$ adsorption layer of IOSP and RTO in sea water so that EDL attractive force always worked between them. Hence, their coagulation reaction occurred at primary minimum on which an extreme attractive force acted because of charge neutralization by $Mg(OH)_2$ adsorption layer of IOSP. As a result, the coagulation reaction was rapidly processed and was irreversible according to DLVO (Deriaguin-Landau-Verwey-Overbeek) theory. Removal rates of RTO were exponentially increased with increasing both IOSP concentration and G-value. The removal rates were steeply increased until 50 mg/l of IOSP and reached $100{\%}\;at\;400\;mg/l$ of IOSP. Removal rates of RTO were $70.5,\;70.5,\;81.7,\;85.3{\%}$ for G-values of $1,\;6,\;29,\;139\;sec^(-1)$at IOSP 100 mg/l, respectively. This indicated that mixing (i.e., collision among particles) was very important for a coagulation reaction.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.15 no.1
• /
• pp.95-101
• /
• 2016

Vehicular communications is system which can be applied for transmission of various safety messages or Intelligent Transportation Systems(ITS) applications by combining vehicle/road technology with Information and Communication Technology(ICT). In recent years, a variety of ITS services are available such as driving information, road conditions, V2X messages as well as navigation and traffic jams notification. In general, vehicular communications can be used for vehicle-to-vehicle and vehicle-to-infrastructure communication by adopting IEEE802.11p/1609 standard which is commonly known as wireless access in vehicular environments. In this paper, WAVE communication standard based on the IEEE802.11p is explained and signal characteristics in WAVE communication is introduced. Also, The H/W and S/W characteristics in Road Side Station and On Board Equipment for the Vehicle to Everything communication are analyzed. Received Signal Strength which is power of receiving signal of communication equipment is measured in test road to estimate the real WAVE communication's performance. It is shown that the implemented WAVE communication technology is satisfactory to provide ITS services.

• Journal of Sensor Science and Technology
• /
• v.4 no.1
• /
• pp.3-8
• /
• 1995

n-ITO/p-PSL heterojunction photodetector have been fabricated on the Si wafer by using ITO(indium tin oxide) and PSL(porous silicon layer). They were anodized selectively by using silicon nitride and Ni-Cr/Au and were passivated by using ITO as well as being isolated by using mesa structure. With white light from 0 to 3000 Lux, the photocurrent varied linearly with incident light intensity. The reverse characteristics of fabricated devices were very stable up to a bias voltage of -40V and dark current density was about $40nA/mm^{2}$. When the device was exposed by Xe lamp whose wavelength range from 400nm to 1100nm, the maximum photo responsivity was about 0.6A/W between 600 and 700nm. Variation of the characteristics of fabricated devices after 5 weeks was negligible.

• Korean Parent-Child Health Journal
• /
• v.17 no.1
• /
• pp.1-7
• /
• 2014

Purpose: The research was to identify menstrual regularity & mental health-related factors on unmarried women of childbearing age and provide a raw material in terms of setting up health policy. Methods: The KNHANE V-3 (The Fifth Korea National Health and Nutrition Examination Survey) was used and implemented through spss 18.0. Results: In general characteristics, there wasn't any remarkable difference between 20s and 30s. Looking further Mental health-related factors, stress was higher in 30s (p=.010). In 30s of irregularity mensutration women, it was accounted for 12.5% over than 3months experienced. General characteristics varied by menstrual regularity were age (p=.044), education level (p=.035) and in terms of mental health-related factors, they were stress (p=.044), sleeping time (p=.039). Multiple regression analysis was carried out to identify how influential these factors are on menstrual regularity. As a result, age, education level, sleeping time & stress was the most influence factors. Conclusion: The research had some limitations to specify and approach the feature of target in depth through KNHANE V-3. Thus, if the basic analysis regarding the menstrual problem in relation to local society was conducted on the basis of the result of research, it could help developing the promotion of health program and make the application easier.

• Journal of Surface Science and Engineering
• /
• v.34 no.5
• /
• pp.475-480
• /
• 2001

Diffusion of Cu into the low-k para-xylene based plasma polymer (pXPP) thin films deposited by plasma-enhanced chemical vapor deposition using the para-xylene precursor was comparatively measured using various methods. Cu layer was deposited on the surfaces of pXPPs treated by $N_2$ plasma generated in a magnetically enhanced inductively coupled plasma reactor. Diffusion characteristics of Cu into pXPPs were measured using Rutherford backscattering spectroscopy (RBS), secondary ion mass spectroscopy (SIMS), cross-sectional transmission electron microscopy (XTEM), and current-voltage (I-V) measurements for the vacuum-annealed Cu/pXPPs for 1 hour at $450^{\circ}C$ and were compared. The results showed a correlation between the I-V measurement and SIMS data are correlated and have a sensitivity enough to evaluate the dielectric properties but the RBS or XTEM measurements are not sufficient to conclude the electrical properties of low-k dielectrics with Cu in the film bulk. The additional results indicate that the pXPP layers are quite resistant to Cu diffusion at the annealing temperature of $450^{\circ}C$ compared to the other previously reported organic low-k materials.

• Applied Chemistry for Engineering
• /
• v.30 no.4
• /
• pp.504-508
• /
• 2019

The feasibility of replacing the tope cell of pn GaInP homojunction with our GaInP/AlGaInP heterojunction structure in III-V semiconductor multijunction photovoltaic (MJPV) cells having the highest current conversion efficiency was investigated. The performance of photovoltaic (PV) cells grown on $2^{\circ}$ and $10^{\circ}$ off-oriented GaAs substrates were compared to each other. The PV cells on the $10^{\circ}$ off-cut substrate showed higher short-circuit current density ($J_{sc}$) and conversion efficiency values than that of using the $2^{\circ}$ one. For $2{\times}2mm^2$ area PV cell on $10^{\circ}$ off substrate, the $J_{sc}$ of $9.21mA/cm^2$ and the open-circuit voltage of 1.38 V were measured under 1 sun illumination. For $5{\times}5mm^2$ cell on $10^{\circ}$ off substrate, the conversion efficiency was decreased from 6.03% (1 sun) to 5.28% (20 sun) due to a decrease in fiill factor (FF).

• Proceedings of the KIEE Conference
• /
• 2006.10a
• /
• pp.77-78
• /
• 2006

최근 flexible OLED의 구동에 사용하기 위한 유기박막트랜지스터(Organic Thin Film Transistor, OTFT)의 연구에서는 용매에 용해되어 spin coating이 가능한 재료의 개발에 관심을 두고 있다. 현재 pentacene으로는 아직 spin coating으로 제작할 수 있는 상용화된 제품이 없고 spin coating이 가능한 활성층 물질(active material)로 P3HT가 쓰이고 있다. 본 연구에서는 용해 가능한 P3HT 활성층 물질과 여러 종류의 용해 가능한 게이트 절연물(gate insulator, Gl)을 사용하여 안정된 소자를 구현할 수 있는 공정을 개발하는 목적으로 metal-insulator-semironductor(MIS) 소자를 제작하여 C-V 특성을 측정하고 분석하였다. 먼저 7mm${\times}$7mm 크기의 pyrex glass 시편 위에 바닥 전극으로 $1600{\AA}$ Au을 증착하고 spin coating 방식을 이용하여 PVP, PVA, PVK, BCB, Pl의 5종류의 게이트 절연층을 각각 형성하였고 그 위에 같은 방법으로 P3HT를 코팅하였다. P3HT 코팅 시 bake 공정의 유무와 spin rpm의 변화에 따른 P3HT의 두께를 측정하였다. Gl의 종류별로 주파수에 따른 capatltancc를 측정하여 비교, 분석하였다. C-V 측정 결과 PVP, PVA, PVK, BCB, Pl의 단위 면적당 capacitance 값은 각각 1.06, 2.73, 2.94, 3.43, $2.78nF/cm^2$로 측정되었다. Threshold voltage, $V_{th}$는 각각 -0.4, -0.7, -1.6, -0.1, -0.2V를 나타냈다. 주파수에 따른 capacitance 변화율을 측정한 결과 Gl 물질 모두 주파수가 높을수록 capacitance가 점점 감소하는 경향을 보였으나 1${\sim}$2nF 이내의 범위에서 작은 변화율만 나타냈다. P3HT의 두께와 bake 온도를 변화시켜 C-V 값을 측정한 결과 차이는 없었다. FE-SEM으로 관찰한 결과에서도 두께나 온도에 따른 P3HT의 표면 morphology 차이를 확인할 수 없었다. 본 연구에서 PVK와 P3HT의 조합이 수율(yield)면에서 가장 안정적이면서 $3.43\;nF/cm^2$의 가장 높은 capacitance 값을 나타내고 $V_{th}$ 값 또한 -1.6V로 가장 낮은 값을 보였다.