We performed temperature dependent current-voltage (I-V) measurements to characterize the electrical properties of Au/Al2O3/n-Ge metal-insulator-semiconductor (MIS) diodes prepared with and without H2O prepulse treatment by atomic layer deposition (ALD). By considering the thickness of the Al2O3 interlayer, the barrier height for the treated sample was found to be 0.61 eV, similar to those of Au/n-Ge Schottky diodes. The thermionic emission (TE) model with barrier inhomogeneity explained the final state of the treated sample well. Compared to the untreated sample, the treated sample was found to have improved diode characteristics for both forward and reverse bias conditions. These results were associated with the reduction of charge trapping and interface states near the Ge/Al2O3 interface.

천연색소는 색을 발현할 수 있는 물질로서 식품, 화장품, 의약품 등에 사용된다. 천연색소는 동・식물에서 추출하여 만들기 때문에 크기가 균일하지 않으며 특히 적색색소의 경우, 다른 색의 색소 에 비해 친유성이 강해 수용액 상태에서 쉽게 응집이 되는 경향이 있다. 또한 응집에 의한 크기변화로 인해 색의 재현이 어려운 문제점이 있다. 적색색소로 기존에 사용했던 동물성 색소인 코치닐 추출 색 소는 알레르기를 유발하고 식용으로서의 거부감이 있는 등의 문제점으로 인하여 사용이 기피되는 추 세이다. 본 연구에서는 적색의 식물성 색소인 라이코펜 추출물과 치자황색소를 사용하였고 Ball-milling을 이용하여 색소의 크기를 균일하게 만든 후 Asymmetrical flow field-flow fractionation(AsFlFFF), Dynamic light scattering(DLS)를 이용하여 크기를 분석하고 색차계를 이용하 여 색을 확인하는 연구를 진행하였다. 실험결과 milling 전에는 색소 입자의 크기가 크고 크기분포가 넓었으나, milling 후에는 크기가 감소하고 크기분포가 좁아짐을 확인하였다. 색차계 측정 결과, milling 시간이 증가함에 따라 밝기, 적색도, 황색도가 높아져서 밝은 적색을 나타내었다.

Aluminum-oxide(Al2O3) thin films were deposited by electron cyclotron resonance plasma-enhanced atomic layer deposition at room temperature using trimethylaluminum(TMA) as the Al source and O2 plasma as the oxidant. In order to compare our results with those obtained using the conventional thermal ALD method, Al2O3 films were also deposited with TMA and H2O as reactants at 280 oC. The chemical composition and microstructure of the as-deposited Al2O3 films were characterized by X-ray diffraction(XRD), X-ray photo-electric spectroscopy(XPS), atomic force microscopy(AFM) and transmission electron microscopy(TEM). Optical properties of the Al2O3 films were characterized using UV-vis and ellipsometry measurements. Electrical properties were characterized by capacitance-frequency and current-voltage measurements. Using the ECR method, a growth rate of 0.18 nm/cycle was achieved, which is much higher than the growth rate of 0.14 nm/cycle obtained using thermal ALD. Excellent dielectric and insulating properties were demonstrated for both Al2O3 films.

Piezodialysis involves the preferential permeation of ions over water molecules through charge mosaic membranes (CMM). This energy-efficient process incites interest as an alternative route to water desalination. But the development of effective CMMs remains a challenge due to their difficult fabrication. Herein, preparation of the positive and negative domains of a CMM were optimized. Negative poly(sodium styrene sulfonate) was blended in poly(vinyl alcohol) matrix, same as that of the positive poly(diallyldimethyl ammonium chloride). Results reveal that a balance between the two domains is critical for the CMM to achieve high salt enrichment and mechanical stability. This work was supported by NRF funded by the Korea government (MSIP) (No. 2017R1A2B2002109) and Basic Science Research Program of Ministry of Education (2009-0093816).

Membrane distillation (MD) is a hydrid membrane process using the temperature difference as a driving force. In order to enhance the performance (flux) of the MD process, various membrane structures (asymmetric or bi-composite) and materials (PP, PVDF or PTFE) have been suggested. In this study, the support layer of the commercial PTFE/PP bi-composite membrane is modifed by forming the macro punctures in it. The size and location of macro punctures were varied according to the designed support layer porosities (50, 60, 70 and 80 %). The modified membrane test was conducted by using the DCMD configuration. The flux of a modified membranewas enhanced up to 27 % compared with that of pristine membrane when the size of the macro puncture and overall porosity of the support layer were larger than 20 mm2 and 60 %, respectively.

CFRP hardened by carbon fiber and resin has the property of high strength and low weight. Specifically, the strong feature against the external vibration environment is shown as CFRP is designed with the structure of multi-axes. So, CFRP in place of metal has been used at the various fields. CFRP specimens for mode Ⅱ are applied with the repetitive fatigue load in this study. These specimens have the fiber layer angles of 30°, 45° and 60°. The material properties of specimens are investigated with the result of fatigue fracture due to this load. As the study result, the smallest and largest reaction forces of 500 N and 540 N are shown at the layer angle of 30° and 60° respectively among these specimens. The separation of adhesive interface at 4000 fatigue cycles is happened earliest in case of the layer angle of 60°. But the separation of adhesive interface at 11000 fatigue cycles is happened latest in case of the layer angle of 45°. Through the result of fatigue property, it is thought that the basis data can be applied to evaluate the safety at CFRP structure applied with fatigue.

MOF(Metal-organic frameworks)의 일종인 ZIF-8은 큰비표면적과 높은 열적⋅ 화학적 안정성을 가지고 있어 분리막 재료로 많은 연구가 진행되고 있다. 특히, 3.4Å 크기의 기공입구와 11.6 Å 크기의 기공 크기를 가지고 있는 ZIF-8을 분리 막으로 합성시 프로필렌/프로판을 분자체 효과를 통해 분리해 낼 수 있다. 본 연구에서는 ZnO 층을 형성하고 이를 전환시켜 결함 없는 ZIF-8 막을 합성하고 이를 통해 프로필렌/프로판을 분리하고자 했다. 우선, 매크로기공을 가진 디스크 모양의 α-알루미나 지지체 위에 ZnO 층을 형성하고, 2-methylimidazole 용액에서 용매열 합성하여 ZnO를 ZIF-8 분리막으로 전환시켰다. 합성된 ZIF-8 분리막 은 XRD, SEM, 기체투과장치, GC 등을 이용하여 분석하였다.

Nanosized zeolites were prepared in an autoclave using tetraethoxysilane (TEOS), tetrapropylammonium hydroxide (TPAOH), and H2O, at various hydrothermal synthesis temperatures. Using transmission electron microscopy and particle size analysis, the nanopowder particulate sizes were revealed to be 10-300 nm. X-ray diffraction analysis confirmed that the synthesized nanopowder was silicalite-1 zeolite. Using atomic layer deposition, the fabricated zeolite nanopowder particles were coated with nanoscale TiO2 films. The TiO2 films were prepared at 300 oC by using Ti[N(CH3)2]4 and H2O as precursor and reactant gas, respectively. In the TEM analysis, the growth rate was ~0.7 Å/cycle. Zeta potential and sedimentation test results indicated that, owing to the electrostatic repulsion between TiO2-coated layers on the surface of the zeolite nanoparticles, the dispersibility of the coated nanoparticles was higher than that of the uncoated nanoparticles. In addition, the effect of the coated nanoparticles on the photodecomposition was studied for the irradiation time of 240 min; the concentration of methylene blue was found to decrease to 48%.

폴리설폰막 위에 친수성 고분자를 Layer-by-Layer법으로 코팅하여 복합막을 제조하였다. FE-SEM 분석을 통하여 복합막 표면과 기공 내 코팅층을 확인하였다. 또한 100 ppm NaCl 용액에 대한 복합막의 투과성능 평가를 실시하였다. 복합 막 제조를 위한 코팅 고분자는 PVSA, PEI, PAA, PSSA, PSSA_MA를 사용하였다. 폴리설폰막 표면에 8,000 ppm PAA (이 온세기 0.35) 수용액을 3분 동안 코팅한 뒤 10,000 ppm PEI 수용액을 4분 동안 코팅하였다. 그 결과 PAA-PEI 복합막의 투과 도는 101 LMH, 제거율은 66.7%로 가장 좋은 투과성능을 나타내었다. PAA-PEI 복합막의 투과성능은 도레이케미칼의 NE 4040-70 (투과도 = 30 LMH, 염 배제율 = 40~70%) 제품과 유사한 성능을 보여주는 우수한 투과 특성을 나타내었다.

중공사막 지지체에 계면중합반응을 통해 막을 형성하여 복합막을 제조하였으며 복합막의 성능평가를 위해 코팅용액의 농도, 코팅시간 및 건조온도 등을 변화시켜 실험을 수행하였다. PART 1 실험에서는 PVAm과 -NH 작용기를 갖는 수용상의 PEI, -COCl작용기를 갖는 유기상의 Trimesoyl chloride 사이의 계면중합 반응을 통해 복합막을 제조하였다. PART 2 실험에서는 PEI를 piperazine(PIP)으로 대체하여 계면중합반응을 하였다. PART 1에서는 PVAm 10,000ppm과 PEI 4,000ppm을 혼합하였을 때 투과도와 배제율 측면에서 가장 좋은 결과를 보였으며 PART 2에서는 PVAm과 PIP의 농도가 높아짐에 따라 투과도는 감소하고 배제율은 증가하는 결과를 얻었다.

Polytetrafluoroethylene (PTFE) membrane has high resistance to chlorine, which is a great advantages in chemical cleaning to recover water flux during membrane processes in drinking water systems. A humic kaolin water with approximately 4 mg/L of DOC and 10 NTU of turbidity was prepared as a feed water. Coagulation pretreatment with or without settling was applied. The coagulation with settling showed the greatest water production. The reduced flux was effectively recovered by NaOCl cleaning, i.e., 21% recovery by 50 mg/L of NaOCl cleaning and 49% recovery by 500 mg/L NaOCl cleaning. The images of SEM and AFM analyses were corresponded to the water flux variation. However, when the floc was accumulated on the membrane surfaces, the efficiency of NaOCl cleaning was substantially limited. In addition, dynamic contact angle became greater after cleaning, which indicates changes in characteristics of fouling layer such as surface hydrophobicity. Proper cleaning technologies during enhanced backwash using NaOCl would expand application of PTFE membranes in drinking water systems.

In this study, in order to improve the efficiency of n-type monocrystalline solar cells with an Alu cell structure, we investigate the effect of the amount of Al paste in thin n-type monocrystalline wafers with thicknesses of 120 μm, 130 μm, 140 μm. Formation of the Al doped p+ layer and wafer bowing occurred from the formation process of the Al back electrode was analyzed. Changing the amount of Al paste increased the thickness of the Al doped p+ layer, and sheet resistivity decreased; however, wafer bowing increased due to the thermal expansion coefficient between the Al paste and the c-Si wafer. With the application of 5.34 mg/cm2 of Al paste, wafer bowing in a thickness of 140 μm reached a maximum of 2.9 mm and wafer bowing in a thickness of 120 μm reached a maximum of 4 mm. The study’s results suggest that when considering uniformity and thickness of an Al doped p+ layer, sheet resistivity, and wafer bowing, the appropriate amount of Al paste for formation of the Al back electrode is 4.72 mg/cm2 in a wafer with a thickness of 120 μm.

(PDDA/SiO2) thin films that consisted of positively charged poly (diallyldimethylammonium chloride) (PDDA) and negatively charged SiO2 nanoparticles were fabricated on a glass substrate by an applying voltage layer-by-layer (LBL) self-assembly method. In this study, the microstructure and optical properties of the (PDDA/SiO2) thin films coated on glass substrate were measured as a function of the applied voltage on the Pt electrodes. When 1.0 V was applied to a Pt electrode in a PDDA and SiO2 solution, the thickness of the (PDDA/SiO2)10 thin film increased from 79 nm to 166 nm. The surface roughness also increased from 15.21 nm to 33.25 nm because the adsorption volume of the oppositely charged PDDA and SiO2 solution increased. Especially, when the voltage was applied to the Pt electrode in the SiO2 solution, the thickness increase of the (PDDA/SiO2) thin film was larger than that obtained when using the PDDA solution. The refractive index of the fabricated (PDDA/SiO2) thin film was ca. n = 1.31~1.32. The transmittance of the glass substrate coated by (PDDA/SiO2)6 thin film with a thickness of 106 nm increased from ca. 91.37 to 95.74% in the visible range.

A thin Cu seed layer for electroplating has been employed for decades in the miniaturization and integration of printed circuit board (PCB), however many problems are still caused by the thin Cu seed layer, e.g., open circuit faults in PCB, dimple defects, low conductivity, and etc. Here, we studied the effect of heat treatment of the thin Cu seed layer on the deposition rate of electroplated Cu. We investigated the heat-treatment effect on the crystallite size, morphology, electrical properties, and electrodeposition thickness by X-ray diffraction (XRD), atomic force microscope (AFM), four point probe (FPP), and scanning electron microscope (SEM) measurements, respectively. The results showed that post heat treatment of the thin Cu seed layer could improve surface roughness as well as electrical conductivity. Moreover, the deposition rate of electroplated Cu was improved about 148% by heat treatment of the Cu seed layer, indicating that the enhanced electrical conductivity and surface roughness accelerated the formation of Cu nuclei during electroplating. We also confirmed that the electrodeposition rate in the via filling process was also accelerated by heat-treating the Cu seed layer.

As ICT advances, industries related to digital technology are disrupting the boundaries of corporations and increasingly interested in the industrial ecosystem. The electronic game industry is also continuously growing through convergence among various technologies, content genres and platforms. Accordingly, this study analyzed the hierarchical elements of hybrid game contents from the viewpoint of the ecosystem as well as the importance and influence their components have upon each level. To understand the importance and influence of the components of the ecosystem from the viewpoint of the value chain of hybrid game contents, an Expert Delphi Survey was conducted employing 18 experts from the game industry, academia and R&D institutions. The results of the Expert Delphi Survey were compiled, a hybrid game ecosystem defined for each layer, and a communication system diagram created depicting the relationship between the ecosystem and value chain of the hybrid game contents. Based on the analysis, to invigorate hybrid game contents, a direction for policies was presented for each hierarchy from both the micro and macro perspectives.

본 연구는 온실의 관류전열량을 분석하고 예측하는데 필요한 기초자료 제공을 위하여, 공기막 이중 PO필름의 열저항식을 모델링하였고, 전도, 복사, 대류에 의한 열저항 특성을 규명하였다. 또한 열저항식의 타당성 검증을 위해 열저항식에 의한 관류전열량의 계산값과 실험값을 비교·분석하였다. 공기막 이중 PO필름의 열저항식은 PO필름, 공기막, PO필름의 직렬 열저항식으로 구성되며, 공기막은 복사와 대류에 의한 병렬 열저항식으로 구성된다. 고온부 T1의 평균온도는 276.1K, 저온부 T2의 평균온도는 266.8K로 나타났으며, 다른 조건들이 동일할 경우 챔버 내부온도가 높을수록 T1과 T2의 평균온도와 온도차가 증가하는 것을 확인할 수 있었다. 전도열저항은 0.00091K ·W−1로 전체 열저항의 1% 미만으로 매우 미미한 수준이고, 공기막의 열저항이 0.18K ·W−1로 전체 열저항의 99% 이상을 차지하는 것으로 나타났다. 공기막의 경우 대류열 저항이 복사열저항에 비해 1.33~2.08배 정도 크게 나타났으며, 복사열저항은 평균온도의 3제곱에 반비례하고 대류열저항은 온도차가 4.7, 5.3, 5.5, 5.7, 12.3, 13.2, 13.3, 13.5, 13.8 및 14.0K로 증가할 때 각각 0.78, 0.75, 0.74, 0.73, 0.57, 0.56, 0.56, 0.56, 0.55 및 0.55K ·W−1 로 감소하였다. 관류전열량의 계산값과 실험값의 차이는 실험조건별로 0.6~17.2W의 범위로 평균 6.9W였으며, 실험값은 계산값의 79.8~97.7% 범위로 평균 87.3% 수준으로 나타났다. 전체적인 계산값과 실험값의 관류전열량 경향성은 잘 일치하고 있으며, 공기막 이중필름의 열 저항은 공기막 두께 및 주입공기의 종류와는 직접적인 상관관계를 보이지 않았다.

In this study, we present a facile method of fabricating graphene oxide (GO) filmson the surface of polyimide (PI) via layer-by-layer (LBL) assembly of charged GO. The positively charged amino-phenyl functionalized GO (APGO) is alternatively complexed with the nega-tively charged GO through an electrostatic LBL assembly process. Furthermore, we investi-gated the water vapor transmission rate and oxygen transmission rate of the prepared (reduced GO [rGO]/rAPGO)10 deposited PI film(rGO/rAPGO/PI) and pure PI film.The water vapor transmission rate of the GO and APGO-coated PI composite filmwas increased due to the intrinsically hydrophilic property of the charged composite films.However, the oxygen trans-mission rate was decreased from 220 to 78 cm3/m2·day·atm, due to the barrier effect of the graphene filmson the PI surface. Since the proposed method allows for large-scale production of graphene films, it is considered to have potential for utiliation in various applications.

Al-doped ZnO(AZO) thin films were synthesized using atomid layer deposition(ALD), which acurately controlledthe uniform film thickness of the AZO thin films. To investigate the electrical and optical properites of the AZO thin films,AZO films using ALD was controlled to be three different thicknesses (50nm, 100nm, and 150nm). The structural, chemical,electrical, and optical properties of the AZO thin films were analyzed by X-ray diffraction, X-ray photoelectron spectroscopy,field-emssion scanning electron microscopy, atomic force microscopy, Hall measurement system, and UV-Visspectrophotometry. As the thickness of the AZO thin films increased, the crystallinity of the AZO thin films gradually increased,and the surface morphology of the AZO thin films were transformed from a porous structure to a dense structure. The averagesurface roughnesses of the samples using atomic force microscopy were ~3.01nm, ~2.89nm, and ~2.44nm, respectively. Asthe thickness of the AZO filmsincreased, the surface roughness decreased gradually. These results affect the electrical and opticalproperties of AZO thin films. Therefore, the thickest AZO thin films with 150nm exhibited excellent resistivity (~7.00×10−4Ω·cm), high transmittance (~83.2%), and the best FOM (5.71×10−3Ω−1). AZO thin films fabricated using ALD may be usedas a promising cadidate of TCO materials for optoelectronic applications.

Cold spray deposition using Titanium powder was carried out to investigate the effects of powder morphology and powder preheating on the coating properties such as porosity and hardness. The in-flight particle velocity of Ti powder in cold spray process was directly measured using the PIV (particle image velocimetry) equipment. Two types of powders (spherical and irregular ones) were used to manufacture cold sprayed coating layer. The results showed that the irregular morphology particle appeared higher in-flight particle velocity than that of the spherical one under the same process condition. The coating layer using irregular morphology powder represented lower porosity level and higher hardness. Two different preheating conditions (no preheating and preheating at ) were used in the process of cold spraying. The porosity decreased and the hardness increased by conducting preheating at . It was found that the coating properties using different preheating conditions were dependent not on the particle velocity but on the deformation temperature of particle. The deposition mechanism of particles in cold spray process was also discussed based on the experimental results of in flight-particle velocity.