• Journal of the Korean Vacuum Society
• /
• v.12 no.S1
• /
• pp.56-59
• /
• 2003

Wurtzite GaN films are grown by low-pressure MOCVD on (0001)-plane sapphire substrates. The GaN films have a total thickness of 4 $\mu$m with a surface Mg-doped p-type layer, which has a thickness of 0.5 $\mu$m. 90k eV $Mn^{+}$ ions are implanted into the GaN films at room temperature with doses ranging from $1 \times10^{15}$ to $1 \times 10^{16}\textrm{cm}^{-2}$. After an annealing step at $770^{\circ}C$ in flowing $N_2$, the structural characteristics of the $Mn^{+}$ implanted GaN films are studied by X-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS) and atomic force microscopy (AFM). The structural and morphological changes brought about by $Mn^{+}$ implantation and annealing are characterized.

• Korean Journal of Materials Research
• /
• v.4 no.7
• /
• pp.759-766
• /
• 1994

Our investigation aimed to reduce the leakage current of $Ta_2O_5$ thin film capacitor by layering SnOz thin film layer under Ta thin film, thereby supplying extra oxygen ions from the $SnO_{2}$ underlayer to enhance the stoichiometry of $Ta_2O_5$ during the oxidation of Ta thin film. Tantalum was evaporated by e-beam or sputtered on p-Si wafers with various deposition temperatures and was oxidized by dry--oxygen at the temperatures between $500^{\circ}C$ and $900^{\circ}C$. Aluminum top and bottom electrodes were formed to make Al/$Ta_2O_5$/p-Si/Al or $Al/Ta_2O_5/SnO_2$p-Si/AI MIS type capacitors. LCR meter and pico-ammeter were used to measure the dielectric constants and leakage currents of the prepared thm film capacitors. XRD, AES and ESCA were employed to confirm the crystallization of the thin f~lm and the compositions of the films. Dielectric constant of $Ta_2O_5$ thin film capacitor with $SnO_{2}$ underlayer was found to be about 200, which is about 10 times higher than that of $Ta_2O_5$ thin film capacitor without $SnO_{2}$ underlayer. In addition, higher oxidation temperatures increased the dielectric constants and reduced the leakage current. Higher deposition temperature generally gave lower leakage current. $Ta_2O_5/SnO_2$ capacitor deposited at $200^{\circ}C$ and oxidized at $800^{\circ}C$ showed significantly lower leakage current, $10^{-7}A/\textrm{cm}^2$ at $4 \times 10^{5}$V/cm, compared to the one without $SnO_{2}$ underlayer. XRD showed that $Ta_2O_5$ thin film was crystallized above $700^{\circ}C$. AES and ESCA showed that initially the $SnO_{2}$, underlayer supplied oxygen ions to oxidize the Ta layer, however, Sn also diffused into the Ta thin film layer to form a new $Ta_xSn_YO_Z$ , ternary oxide layer after all.

• Journal of Bio-Environment Control
• /
• v.14 no.1
• /
• pp.38-45
• /
• 2005

This research was conducted to determine the effect of fertilization programs on crop growth, nutrient uptake and yield of strawberry and salt accumulation in PE film house soil. To achieve these, experiments were conducted through two years with various fertilization program such as traditional fertilization(A), recommended fertilization of Rural development administration (B), Tochigi prefectural experiment station (C) and Nonsan strawberry experiment station (D), and control (E). In 1st year, statistical differences in growth characteristics were not observed among treatments except (E). Yield per 10 was the highest in (D) followed by (A), (B), (C) and (E) and there was the statistical difference between (D) and (E). In the 2nd year experiment, growth characteristics and yield showed similar trends to those of 1st year experiment. In the results of soil analysis of 2nd year, the soil pH of all treatments were in the acceptable range, while electrical conductivity of (A) and (D) were 2.36 and 2.19 %$dS{\cdot}m^{-1}$, respectively. After finishing of strawberry cultivation, nitrate concentration in soil solution of (A) and (D) were 74.6 and 65.0%$mg{\cdot}L^{-1}$ and Na in those were 3.71 and 3.53 $cmol+kg^{-1}$, respectively. Above results indicated that (A) and (D) were good fertilization program for strawberry cultivation, but those also resulted in accumulation of $NO_{3-}N$ and Na in PE house soil.

• Korean Journal Plant Pathology
• /
• v.14 no.1
• /
• pp.13-18
• /
• 1998

The use of bioluminescence as a sensitive marker for the detection of Pseudomnas sp. in the rhizosphere was investigated. Transposon Tn4431 which contains a promoterless luciferase operon and tetracycline resistant gene was used. This transposon, present on a suicide vector (pUCD623) in E. coli HB101, was mated with spontaneous rifampicin mutant of Pseudomonas fluorescens B16, a plant growth promoting rhizobacteria (PGPR), and then rifampicin and tetracycline resistant survivors were isolated. Twenty tow mutants wer isolated from the conjugants between E. coli HB101 and P. fluorescens B16. One of these, B16::Tn4431 (L22) recombinant which glowed brightly in the dark was selected for analysis. The cucumber seeds inoculated with L22 were grown in moisten two layers of filter paper and nonsterile soil contained in half cut PVC pipe. The roots were removed from the filter paper and PVC pipe, then placed on the 1/2 LB media plates. The plates were incubated at room temperature for 16 hr. L22 could successfully be detected in the rhizoplane by using the ordinary negative camera film (ASA100-400) with 30 minutes exposure under dark condition. The root colonizing ability and the plant growth promoting effect of L22 were not reduced compared to the untreated bacteria and wild type. L22 was superior to will type.

• Journal of Sensor Science and Technology
• /
• v.27 no.1
• /
• pp.40-46
• /
• 2018

In this paper, we focus on optimization of a boron ($^{11}B$)-implanted n type Si epi substrate for obtaining near-zero temperature coefficient of resistance (TCR) at temperature range from 25 to $125^{\circ}C$. The $^{11}B$-implantation on the N type-Si epi substrate formed isolation from the rest of the N-type Si by the depletion region of a PN junction. The TCR increased as the temperature of rapid thermal anneal (RTA) was increased at the temperature range from $900^{\circ}C$ to $1000^{\circ}C$ for the $p^+$ contact with implantation at dose of $1E16/cm^2$, but sheet resistance of this film was decreased. After the optimization of anneal process condition, the TCR of $1126.7{\pm}30.3$ (ppm/K) was obtained for the $p^-$ resistor-COB package chips contained $p^+$ contact with the implantation of $5E14/cm^2$. This shows the potential of the $^{11}B$-implanted n type Si epi substrate as a resistor for pressure sensor in thermal stable environment applications..

• 한국정보디스플레이학회:학술대회논문집
• /
• 2008.10a
• /
• pp.1459-1462
• /
• 2008

In this paper we describe solutions to address critical challenges in direct fabrication of amorphous silicon thin film transistor (TFTs) arrays for active matrix flexible displays. For all flexible substrates a manufacturable handling protocol in automated display-scale equipment is required. For metal foil substrates the principal challenges are planarization and electrical isolation, and management of stress (CTE mismatch) during TFT fabrication. For plastic substrates the principal challenge is dimensional instability management.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.46 no.2
• /
• pp.9-14
• /
• 2009

The effects of post-annealing temperature on the optical and electrical properties of P-doped ZnO thin films grown on sapphire substrate have been investigated under oxygen ambient. The XRD shows that regardless of the post-annealing temperature, all P-doped ZnO thin films indicate the c-axis orientation. The results of hall effect measurements indicate the P-doped ZnO thin film annealed at $850^{\circ}C$ exhibits p-type behavior with hole concentration of $1.18{\times}1016cm^{-3}$ and hole mobility of $0.96cm^2/Vs$. The low-temperature (10K) Photoluminescence results reveal that the peak related to the neutral-acceptor exciton (A0X), free electrons to neutral acceptor (FA) and donor acceptor pair (DAP) at 3.351ev, 3.283eV and 3.201eV are observed in the films showing p-type behavior with acceptor. The optimization of deposition and post-annealing conditions will certainly make the P-doped ZnO thin films promising materials for the application to the next generation of optical devices.

• Journal of Veterinary Science
• /
• v.21 no.5
• /
• pp.69.1-69.11
• /
• 2020

Background: An inappropriate Q angle may affect the biomechanics of the canine patellofemoral joint. Objectives: The purpose of this study was to evaluate the effects of changes in quadriceps angle (Q angle) on patellofemoral joint pressure distribution in dogs. Methods: Eight stifles were positioned at 45, 60, 75, 90, 105, and 120° of flexion in vitro, and 30% body weight was applied through the quadriceps. Patellofemoral contact pressure distribution was mapped and quantified using pressure-sensitive film. For the pressure area, mean pressure, peak pressure, medial peak pressure, and lateral peak pressure, differences between groups according to conditions for changing the Q angle were statistically compared. Results: Increases of 10° of the Q angle result in increases in the pressure area (P = 0.04), mean pressure (P = 0.003), peak pressure, and medial peak pressure (P ≤ 0.01). Increasing the Q angle by 20° increases the pressure area (P = 0.021), mean pressure (P ≤ 0.001), peak pressure (P ≤ 0.01), and medial peak pressure (P ≤ 0.01) significantly, and shows higher mean (P ≤ 0.001) and peak pressures than increasing by 10°. Decreasing the Q angle increases the mean pressure (P = 0.013), peak pressure, and lateral peak pressure (P ≤ 0.001). Conclusions: Both increases and decreases in the Q angle were associated with increased peak patellofemoral pressure, which could contribute to the overloading of the cartilage. Therefore, the abnormal Q angle should be corrected to the physiologically normal value during patellar luxation repair and overcorrection should be avoided.

• Bulletin of the Korean Chemical Society
• /
• v.24 no.8
• /
• pp.1155-1162
• /
• 2003

Nanocrystalline semiconductor film electrodes have been prepared by sintering three different sizes of TiO₂ nanoparticle sols on conducting indium-tin-oxide (ITO) glass substrate. The electrochemical and photoelectrochemical properties of the prepared electrodes were comparatively investigated. The particle sizes, surface morphologies and crystallinities of the films were studied by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. Cyclic voltammetry and capacitance measurements in the dark implies the formation of depletion layer in the semiconductor films which was usually neglected in the previous studies and shows that flat band potential ($E_{fb}$

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
• /
• v.15 no.3
• /
• pp.99-104
• /
• 2009

Soy protein isolate (SPI)-based nanocomposite films with three different types of nanoclays, such as Cloisite $Na^+$, Cloisite 20A, and Cloisite 30B, were prepared using a solution casting method, and their optical, tensile, and water vapor barrier properties were determined to investigate the effect of nano-clay type on film properties. Among the tested nanoclays, Cloisite $Na^+$, a hydrophilic montmorillonite (MMT), exhibited the highest transparency with least opaqueness, the highest tensile strength, and the highest water vapor barrier properties, indicating Cloisite $Na^+$ is the most compatible with SPI polymer matrix to form nanocomposite films. The film properties of SPI/Cloisite $Na^+$ nanocomposite films were strongly dependent on the concentration of the clay. Film properties such as optical, tensile, and water vapor barrier properties improved significantly (p<0.05) as the concentration of clay increased. However, the effectiveness of addition of the clay reduced above a certain level (i.e., 5wt%), indicating that there is an optimum amount of clay addition to exploit the full advantage of nanocmposite films.