Gallium Doping Effects for Improving Switching Performance of p-Type Copper(I) Oxide Thin-Film Transistors.

Copper(I) oxide (Cu2O), which is obtained from copper(II) oxide (CuO) through a reduction process, is a p-type oxide material with a band gap of 2.1-2.4 eV. However, the switching performance of typical Cu2O thin-film transistors (TFTs) is poor because the reduction process increases the concentration of oxygen vacancies (VO), which interfere with the conduction of hole carriers. Ga with high oxygen affinity was doped in Cu2O thin films to decrease VO during the reduction process. As a result, the VO concentration of 1.56 at % for Ga-doped Cu2O (Ga:Cu2O) thin films decreased from 20.2 to 7.5% compared to pristine Cu2O thin films. Accordingly, the subthreshold swing or S-factor, on/off-current ratio (Ion/off), saturation mobility (µsat), and threshold voltage (Vth) of Ga:Cu2O TFTs were improved compared to pristine Cu2O TFTs with values of 7.72 from 12.50 V/dec, 1.22 × 104 from 2.74 × 102, 0.74 from 0.46 cm2/Vs, and -4.56 from -8.06 V, respectively. These results indicate that Ga plays an important role in improving the switching performance of p-type Cu2O TFT.

Water Resistances of Ag2O-, BaO-, and CuO-Doped V2O5-P2O5-TeO2 Glass Sealants.

V2O5-P2O5-TeO2, a low-temperature vanadate-based glass sealant, was doped with metal oxides (MO = Ag2O, BaO, or CuO), which generate Ag, Ba, and Cu ions, respectively, to strengthen the glass structure and improve its water resistance. These ions reduce the number of nonbridging oxygen atoms in the glass structure by forming V-O-M or P-O-M crosslinks in the V2O5-P2O5 glass system. Structural analysis using Fourier-transform infrared spectroscopy indicated that the numbers of P-O-P, V═O, and V-O-V bonds decreased with increasing metal oxide content. Thermal property analyses revealed that the glass transition temperatures increased by approximately 2-30 °C and that the coefficients of thermal expansion only varied within approximately ±10×10-7 K-1 among all the glass samples. The contact angles were measured to quantify the wetting properties of the doped glasses. The contact angle increased from 11 to 36° with increasing metal oxide content at 410 °C. As an indication of the water resistances of the doped glasses, the dissolution rates of the 9 mol% Ag2O-doped and pure glasses were 0.078 and 0.523 g cm-2, respectively.

Production of Cu@SiO2 Core-Shell Nanoparticles with Antibacterial Properties.

Antimicrobial agents based on organic materials have limited use owing to their low heat resistance and short lifetimes. Therefore, various studies on antibacterial agents that are based on inorganic material systems are increasingly being performed to supplement them. In this study, Cu@SiO2 core-shells are fabricated using Cu cores and SiO2 shells, and are known to have antimicrobial effects. The core-shell was coated with SiO2 using the sol-gel method. Experiments were conducted using X-ray diffraction and the shaking flask method (KS J 4206) to evaluate the characteristics of the core-shell. In the case of X-ray diffraction, both the Cu core and the core-shell fabricated using the sol-gel process were characterized. Escherichia coli and Staphylococcus aureus were evaluated using the KS J 4206 method for their antibacterial properties. Through this study, it is confirmed that a Cu@SiO2 core-shell can be fabricated via the sol-gel method, and that Cu with a core-shell structure has antibacterial effects.

Head Elevation in Spinal-Epidural Anesthesia Provides Improved Hemodynamics and Appropriate Sensory Block Height at Caesarean Section.

PURPOSE: We aimed to determine whether head elevation during combined spinal-epidural anesthesia (CSE) and Caesarean section provided improved hemodynamics and appropriate sensory block height. MATERIALS AND METHODS: Forty-four parous women undergoing CSE for elective Caesarean section were randomly assigned to one of two groups: right lateral (group L) or right lateral and head elevated (group HE) position, for insertion of the block. Patients were positioned in the supine wedged position (group L) or the left lateral and head elevated position (group HE) until a block height of T5 to light touch was reached. Group HE was then turned to the supine wedged position with maintenance of head elevation until the end of surgery. Hemodynamics, including the incidence of hypotension, ephedrine dose required, and characteristics of the sensory blocks were analyzed. RESULTS: The incidence of hypotension (16 versus 7, p=0.0035) and the required dose of ephedrine [24 (0-40) versus 0 (0-20), p<0.0001] were greater in group L compared to group HE. In group L, the time to achieve maximal sensory block level (MSBL) was shorter (11.8±5.4 min versus 20.1±6.3 min, p<0.0001) and MSBL was also higher than in group HE [14 (T2) versus 12 (T4), p=0.0015]. CONCLUSION: Head elevation during CSE and Caesarean section is superior to positioning without head elevation in the lateral to supine position, as it is associated with a more gradual onset, appropriate block height, and improved hemodynamics.

Selective synthesis of diameter- and interlayer-controlled carbon nitride nanotubes with hydrogen ensnaring nanopores.

Diameter- and interlayer-controlled carbon nitride nanotubes (CNNTs) having nanopores with approximately 6 A diameters are synthesized by our new plasma-assisted growth method on catalysts located inside the organic silica mesoporous templates. Our experiments and first-principles calculations show that hydrogen stored inside nanopores of 6.2 A are attributed to the hydrogen released at 257.24 K.