Progenitors of Type Ib and Ic supernovae (SNe) are stripped envelope stars and provide important clues on the mass-loss history of massive stars. Direct observations of the progenitors before the supernova explosion would provide strong constraints on the exact nature of SN Ib/Ic progenitors. Given that stripped envelope massive stars can have an optically thick wind as in the case of Wolf-Rayet stars, the influence of the wind on the observational properties needs to be properly considered to correctly infer progenitor properties from pre-SN observations. Non-LTE stellar atmosphere models indicate that the optical brightness could be greatly enhanced with an optically thick wind because of lifting-up of the photosphere from the stellar surface to the wind matter, and line and free-free emissions. So far, only a limited number of SN Ib/Ic progenitor candidates have been reported, including iPTF13bvn, SN 2017ein and SN 2019yvr. We argue that these three candidates are a biased sample, being unusually bright in the optical compared to what is expected from typical SN Ib/Ic progenitors, and that mass-loss enhancement during the final evolutionary stage can explain their optical properties.

Feasibility of multiwavelength Raman spectroscopy was studied as a potentialin-line monitoring technique for grain size distribution in channel poly-Si usedin three dimensional stacked NAND (3D NAND) Flash memory devices. Variouschannel poly-Si materials in 3D-NAND Flash memory devices, converted fromchemical vapor deposition (CVD) grown a-Si, were characterized usingnon-contact, multiwavelength Raman spectroscopy and high resolutioncross-sectional transmission electron microscopy (HRXTEM). The Ramancharacterization results were compared with HRXTEM images. The correlationbetween the grain size distribution characterized by multiwavelength Ramanspectroscopy and “on current” (ION) of 3D NANDFlash memory devices was investigated. Good correlation between these techniqueswas seen. Multiwavelength Raman spectroscopy is very promising as anon-destructive in-line monitoring technique for grain size distribution inchannel poly-Si used in 3D NAND Flash memory devices.

We propose a fuzzy weighted subtask controller for a redundant robot manipulator. To expand the feasibility of the inverse kinematic solution, we introduce a weighted pseudo-inverse that changes the null-space of the Jacobian. The weights of elements in the pseudo-inverse are obtained using fuzzy rules that are related to the null-space velocity tracking error. With the pseudo-inverse, we develop a task space controller to track a desired task space trajectory and subtask control input. We propose a weighted subtask controller for multiple subtasks. The results of a simulation and experiment using a seven-degree-of-freedom whole arm manipulator robot show the effectiveness of the proposed controller with multiple subtasks.

The liquid phase plasma reduction method has been applied to prepare silver nanoparticles from a solution of silver nitrate (AgNO3) using a bipolar pulsed electrical discharge system. The excited states of atomic silver, hydrogen and oxygen as well as the molecular bands of hydroxyl radicals were detected in the emission spectra. As the discharge duration increased up to 10 min, silver particle peaks produced by surface plasmon absorption were observed around 430 nm. Both the particle size and the particle numbers were observed to increase with the length of the plasma treatment time and with the initial AgNO3 concentration. Spherical nanoparticles of about 5–20 nm in size were obtained with the discharging time of 5 min, whereas aggregates of nanoparticles of about 10–50 nm in size were mainly produced with the discharging time of 20 min. The cationic surfactant of cetyltrimethylammonium bromide (CTAB) added with the CTAB/AgNO3 molar ratio of 30% was shown to inhibit nanoparticle aggregation.

The purpose of this study was to investigate whether there is any association between preeclampsia and eNOS, DDAH, and VEGF gene polymorphisms, and also to search for a possible association between haplotypes in eNOS, DDHA, and VEGF genes and the risk for preeclampsia. DNA was extracted from whole blood of 223 preeclampsia patients and 237 healthy pregnant women. The genotypes were analyzed by a single base primer extension assay using a SNaPShot assay kit. Results were analyzed with the Student's t-test, Chi-square test, and Logistic regression analysis. Haplotype analyses were performed using Haploview 3.2 version. There were no significant differences in genotype or allele frequencies of eNOS, DDAH, and VEGF gene polymorphisms between preeclampsia patients and controls. No increase in the risk of preeclampsia for those genes was observed under any model of inheritance and there were no statistically significant associations between any haplotypes and preeclampsia risk. Polymorphisms in eNOS, DDAH, and VEGF gene do not seem to be risk factors for preeclampsia.

Background: The influences of demographics, culture, language, and environmental changes on Mini-Mental State Examination (MMSE) scores are considerable.

Methods: Using a sample of 7452 healthy, community-dwelling elderly Koreans, aged 55 to 94 years, who participated in the four ongoing geriatric cohorts in Korea, we investigated demographic influences on MMSE scores and derived normative data for this population. Geropsychiatrists strictly excluded subjects with cognitive disorders according to the protocol of the Korean version of the Consortium to Establish a Registry for Alzheimer's Disease Assessment Packet (CERAD-K) Clinical Assessment Battery (CERAD-K-C).

Results: Education (standardized β = 0.463), age (standardized β = −0.303), and gender (standardized β = −0.057) had significant effects on MMSE scores (p < 0.001). The score of MMSE increase 0.379 point per 1-year education, decrease 0.188 per 1-year older, and decrease 0.491 in women compared to men. Education explained 30.4% of the scores’ total variance, which was much larger than the variances explained by age (8.4%) or gender (0.3%). Accordingly, we present normative data for the MMSE stratified by education (0, 1–3, 4–6, 7–9, 10–12, and ≥ 13 years), age (60–69, 70–79, and 80–89 years), and gender.

Conclusions: We provide contemporary education-, age-, and gender-stratified norms for the MMSE, derived from a large, community-dwelling elderly Korean population sample, which could be useful in evaluating individual MMSE scores.

Metal-insulator-metal (MIM) capacitors were fabricated in a coplanar waveguide type using the Al2O3 thin film. The Al2O3 film was grown by atomic layer deposition(ALD) using Methyl-Pyrolidine-Tri-Methyl-Aluminum (MPTMA) and H2O on Ti. The capacitance per unit area of the fabricated MIM capacitor was 0.229 μF/cm2. And it had lower voltage coefficient of capacitance (VCC) and lower leakage current than that of Al2O3 MIM capacitor prepared by Al oxidation and Si3N4 MIM capacitor prepared by PECVD respectively. The fabricated Al2O3 MIM capacitors prepared by ALD exhibited low VCC, low leakage current, small frequency-dependent capacitance reduction, low temperature coefficient of capacitance (TCC) and good reliability. The characteristics of the device were suitable for RF ICs and DRAM.

Pt/Ti/SiO2/Si substrates seeded by SBT nanoparticles (∼60–80 nm) were used to enhance the phase formation kinetics of Sr0.7Bi2.4Ta2O9 (SBT) thin films. The volume fractions of Aurivillius phase formation obtained through quantitative x-ray diffraction (Q-XRD) analyses showed highly enhanced kinetics in seeded SBT thin films. The Avrami exponents were determined as ∼1.4 and ∼0.9 for unseeded and seeded SBT films, respectively, which reveals different nucleation modes. By using Arrhenius–type plots the activation energy values for the phase transformation of unseeded and seeded SBT thin films were determined to be ∼264 and ∼168 kJ/mol, respectively. This gives a key reason to the enhanced kinetics in seeded films. Microstructural analyses on unseeded SBT thin films showed formation of randomly oriented needle-like crystals, while those on seeded ones showed formation of domains comprised of directionally grown worm-like crystals.

Sr0.7Bi2.4Ta2O9 (SBT) thin films were deposited on Pt/Ti/SiO2/Si substrates with and without a seed layer of ∼40 nm thickness using sol-gel and spin coating methods. The influence of seed layer on the phase formation characteristics of SBT thin films was investigated using x-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. Formation of pyrochlore as well as Aurivillius phase was observed in both the unseeded and seeded SBT films heated at 740°C. However, it was revealed that Aurivillius phase formation was enhanced in seeded SBT thin films and pyrochlore phase formation was highly suppressed. In this study, two possible mechanisms for the suppression of pyrochlore phase formation were proposed from the perspectives of activation energy difference for Aurivillius and pyrochlore phase formation and Bi-ion diffusion to pyrochlore phase.

RF MEMS(Micro-Electro-Mechanical-System) switch technology is one of powerful solution for future RF systems. This technology provides low insertion loss, High linearity and broad bandwidth. Wide driving membrane used MEMS switch can reduce driving voltage but it is easy to bend because of the stress gradient. In order to solve this problem we fabricated Au cantilever in various sputtering condition and various substrate materials. As a result of this experiment, we fabricated cantilever which was bent within 1 um, with 2 um thickness and 340 um length. We applied this condition to RF MEMS switch and we fabricated switch membrane within 1 um bend, under 10MPa stress gradient.

Strontium bismuth tantalate (SBT) having composition of Sr0.7Bi2.4Ta2O9 has been prepared through sol-gel method using their corresponding metal alkoxides as precursors. Seeded SBT powder was prepared by the addition of 5 wt.% of nanometer sized SBT particles to the sol followed by pyrolysis. By applying non-isothermal kinetic analysis to the DTA results, activation energy values for the unseeded and seeded samples were determined. Enhanced crystallization kinetics was observed for the seeded one and the activation energy for the aurivillius phase formation was found to be 318 kJ/mol, while 375 kJ/mol for the unseeded. The Avrami exponent values for the seeded and unseeded were found to be 2.80 and 0.96 respectively.

The crystallization kinetics of SBT and SBT-BTT thin films formed by sol-gel technique on Pt substrate was studied. Phase formation and crystal growth are greatly affected by the film composition and crystallization temperature. Isothermal kinetics analysis was performed on x-ray diffraction (XRD) patterns of the thin films heated in the range 730 to 760° at 10° intervals. Activation energy and Avrami exponent values were determined for the fluorite to Aurivillus phase formation. A reduction of ∼55 kJ/mol in activation is observed for the SBT-BTT system. A comparison has been made and the possible crystallization mechanism is discussed.

Making a comparative study between MOSFET and polycrystalline silicon thin film transistor(poly-Si TFT) in applying the charge pumping method(CPM), the most distinctive difference was found in the relation of the charge pumping current(Icp) versus the gate pulse frequency. According to the conventional theory, Icp increases linearly with the gate pulse frequency. In poly-Si TFT, however, Icp shows complicated dependence on frequency. We modeled the frequency dependence of Icp in poly-Si TFT by considering the resistance of active poly-Si film. According to this model we can extract the parameters such as grain boundary trap density, substrate resistance, and capture cross section.

A surface of thin square PTFE samples (1×1×0.2 cm3) was irradiated with Ar+ ion at 1 keV with varying ion dose from 5 x 1014 to 1 x 1017 ions/cm2 with and without oxygen environment. The chemical structure of the surface was examined by XPS. The high resolution XPS spectra showed decreased intensity of the Fls peak and formation of the Ol s peak when irradiated with O2 environment. The Ols peak reached the maximum height at the ion dose of 1 x l015 ions/cm2. The increase of the Ols peak may be attributed to the reaction of oxygen atoms and the free radicals created by Ar+ bombardment. Adhesion tests were conducted on 2000 Å thick Al or Cu film which was evaporated on the irradiated and unirradiated PTFE samples with and without O2 environment. Full detachment of the metal films was observed when PTFE samples were not modified. With regard to the Al film, partial detachment of the film occurred when PTFE was irradiated without O2 environment, regardless of ion dose. No detachment of the film occurred when PTFE was irradiated with O2 environment with the ion dose exceeding 1 x 1016 ions/cm2. As to the Cu film, partial detachment was observed with or without O2 environment when the ion dose was 5 x 1014 ions/cm2. No detachment occurred with or without O2 environment when the ion dose was 1 x 1015 ions/cm2 or greater. The adhesion of an adhesive (Crystal Bond) to the irradiated PTFE samples was found to increase significantly with increasing ion dose up to 1 x 1016 ions/cm2 in tensile tests. It appears that three separate mechanisms are at work in improving adhesion of Cu/PTFE and Al/PTFE system. The first is the surface roughness of PTFE caused by Ar+ bombardment, the second is the chemical changes on the PTFE surface, and the third is a change of the interface between the metal and PTFE. The wettability of the PTFE surface was also determined by dropping water droplets on the modified surfaces. The contact angle between water droplets and the irradiated surface of PTFE samples decreased with ion dose up to 1 x 1015ions/cm2, increased at higher dose, and finally increased to the extent that no wetting was possible at 1 x 1017 ions/cm2. The PTFE samples irradiated with Ar+ without O2 gas environment had lower contact angle than those with O2, even though the samples with O2 developed hydrophilic groups on the irradiated surface. This result on wettability is not consistent with our earlier results on PMMA and PC and is due to the unusually high level of surface roughness of PTFE caused by Ar+ bombardment.

The effects of electron cyclotron resonance (ECR) N2O-plasma nitridation on the characteristics of thermal SiO2 have been investigated. Although the ECR N2O-plasma nitridation was performed at low-temperature(≤400°C), it was found that oxynitride layer can be successfully grown at the Si/SiO2 interface. The atomic concentration of nitrogen near the Si/SiO2 interface was comparable to that of high temperature N2O annealing. The ECR N2O-plasma nitrided thermal SiO2 exhibits higher breakdown field characteristics, higher time-to-breakdown and charge-to-breakdown values in comparison with those of thermal SiO2. In addition, ECR N2O-plasma nitrided thermal SiO2 shows improved charge trapping properties