Plasma oxidation of Al thin films on Si substrates

In this study, Al thin films deposited on silicon wafers by direct current magnetron sputtering were oxidized under radio frequency 13.56 MHz O₂ plasma at temperatures up to 550 °C. During oxidation, plasma powers as well as oxidation temperature and time were varied to investigate the oxidation behavior of the Al films. X-ray photoelectron spectroscopy and Auger electron spectroscopy results show that the apparent alumina could be observed after O₂ plasma treatment with powers above 200 W as well as at temperatures above 250 °C. However, no alumina increment could be discerned after individual either heat treatment at 550 °C or plasma treatment at room temperature. The thickness of alumina layers increased remarkably with plasma power and could reach about 60 nm when undergone 400 W O₂ plasma treatment at 550 °C for 2 h. Moreover, the thickness of alumina increased parabolically with time during plasma oxidation aided by thermal treatment. The deduced activation energy of such plasma oxidation was 19.1 ± 0.5 kJ/mol.     

Performance comparisons of intelligent load forecasting structures and its application to energy-saving load regulation

This study mainly focuses on the development of intelligent forecasting structures via a similar time method with historical load change rates for the hourly, daily and monthly load forecasting simultaneously based on the basic frameworks of fuzzy neural network (FNN) and particle swarm optimization (PSO). In the regulative aspect of network parameters, conventional back-propagation (BP) and PSO tuning algorithms are used, and varied learning rates are designed in the sense of discrete-time Lyapunov stability theory. The performance comparisons of different intelligent forecasting structures including neural network (NN) structure with BP tuning algorithm (NN-BP), FNN structure with BP tuning algorithm (FNN-BP), FNN structure with BP tuning algorithm and varied learning rates (FNN-BP-V), FNN structure with PSO tuning algorithm (FNN-PSO) and newly-designed adaptive PSO (APSO) structure are verified by numerical simulations. In order to verify the effectiveness of the superior APSO forecasting structure in practical energy-saving load regulation, the load forecasting during every 15 min is also given, and its result is used to manipulate the scheduled unloading control of a real case in Taiwan campus.     

Using machine learning to detect PII from attributes and supporting activities of information assets

Since the implementation of the EU General Data Protection Regulation (“GDPR”) and similar legislation on personal data protection in Taiwan, enterprises must now provide adequate protection for their customers’ personal data. Many enterprises use automated personally identifiable information (“PII”) scanning systems to process PII to ensure full compliance with the law. However, personal data saved in non-electronic form cannot be detected by these automated scanning systems, resulting in PII not being able to be accurately identified. We propose a random forest (“RF”) approach to detect unidentified PII to close the loopholes. Relevant peripheral information attributes of PII are identified and used in our study for machine learning and modeling to establish a model for detecting PII that otherwise cannot be detected by automated scanners. Our study shows that the F1-measure of our proposed model achieves at least 90%, a higher accuracy rate than that of automated scanners in detecting PII in an enterprise’s inventory of information assets. Finally, the results of the experiment in our study show that our proposed model can shorten the time required for detecting PII by 100 times and increase the F1-measure by 2% when compared with the PII detection conducted manually.

     

Applying Ag–TiO2/functional filter for abating odor exhausted from semiconductor and opti-electronic industries

Some of the odor-related problems from the semiconductor and opti-electronic industries are caused by the volatile organic compounds, acetic acid, and dimethyl sulfide. These odorous exhausts would persecute residents’ health and lower the environmental quality. In this study, Ag–TiO₂/functional filter was applied to removal these odorous compounds. The results indicated that K₂CO₃/activated carbon filter (ACF) would be the better composition of functional filter, which attributed to larger surface area of ACF and mid-alkalinity of K₂CO₃. Comparing the TiO₂ type, P25 TiO₂ (Degussa, Germany)/functional filter showed the more superior photodegradation efficiency than ST01 TiO₂ (Ishihra Sangyo, Japan)/functional filter. In addition, Ag-modifying TiO₂/functional filter enhanced the photocatalysis via postponing the recombination between electrons and holes. The 0.001 M AgNO₃ solution was the optimal immersing concentration to make Ag dispersed uniformly on TiO₂ surface. Operating from 25 to 50 °C, the rising temperature was contributive to photodegradation efficiency due to the increase of system reaction energy. Processing photocatalysis below 75 % of relative humidity, existing humidity could be combined with holes to from hydronium (H₃O⁺) and hydroxyl radical (OH^?) to improve photodegradation. Assisted with ozone concentration ratio of 0.7 times, the removal efficiency for high pollutant concentration via Ag–TiO₂/functional filter could be improved up to 90 % until operating 180 min; this combined method could save the oxidant consumption more than single advanced oxidation method for processing pollutant.     

Primary solidification phases of the Sn-rich Sn-Ag-Cu-Ni quaternary system

The eutectic and near-eutectic Sn-Ag-Cu solders are the most promising lead-free solders, and nickel is frequently used as the barrier layer material. Nickel dissolves into the molten Sn-Ag-Ni alloy during the soldering process, and the ternary solder becomes a Sn-Ag-Cu-Ni quaternary melt near the nickel substrate. Liquidus projection is the projection of the liquidus trough and it delineates the boundaries of various primary solidification phases. Information of liquidus projection is helpful for understanding the alloys’ solidification behavior. This study prepared the Sn-Ag-Cu-Ni alloys of various compositions at the Sn-rich corner. The alloys were melted at higher temperatures and solidified in air. The solidified alloys were metallographically examined to determine the phases formed, especially the primary solidification phases. No ternary or quaternary compounds were found. The knowledge of the primary solidification phases, phase formation sequences, and reaction temperatures determined in this study were put together with all of the available liquidus projections of the constituent ternary systems to determine the primary solidification phases of the quaternary Sn-Ag-Cu-Ni system at the Sn-rich corner.     

Effect of the annealing ambient on the electrical characteristics of the amorphous InGaZnO thin film transistors

The influence of the thermal annealing on the amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) under different ambient gases has been systematically addressed. The chemical bonding states and transfer characteristics of a-IGZO TFTs show evident dependence on the annealing ambient gas. For the a-IGZO TFTs in the oxygen ambient annealing at 250 degrees C for 30 mins exhibited a maximum field effect mobility (max muFE) of 9.36 cm2/V x s, on/off current ratio of 6.12 x 10(10), and a subthreshold slope (SS) of 0.21 V/decade. Respectively, the as-deposited ones without annealing possess a max muFE of 6.61 cm2/V x s, on/off current ratio of 4.58 x 10(8), and a SS of 0.46 V/decade. In contrast, the a-IGZO TFTs annealed at 250 degrees C for 30 mins in the nitrogen ambient would be degraded to have a max muFE of 0.18 cm2/V x s, on/off current ratio of 2.22 x 10(4), and a SS of 7.37 V/decade, corresponding. It is attributed to the content of the oxygen vacancies, according the x-ray photoelectron spectroscopy (XPS) analyze of the three different samples.     

Serotype occurrence and antimicrobial susceptibility of Salmonella isolates recovered from pork carcasses in Taiwan (2000 through 2003)

One hundred fifty-eight Salmonella strains isolated from pork carcasses in a nationwide screening program in Taiwan from 2000 through 2003 were analyzed for serotype distribution and antimicrobial susceptibility. Twenty Salmonella serotypes were obtained, among which Derby, Anatum, Typhimurium, and Schwarzengrund were the most frequently isolated, accounting for 76% of the strains. Antimicrobial susceptibility tests with the microdilution method were performed on these serotypes to determine the MIC. All strains tested were sensitive to ceftriaxone, with an MIC90 (minimum concentration inhibiting 90% of isolates tested) of 0.25 to 8 microg/ml. More than 60% of the strains were resistant to ampicillin, chloramphenicol, tetracycline, nalidixic acid, and sulfamethoxazole, with MIC90 values of 128 to >512 microg/ml. More than 80% of the Salmonella Schwarzengrund strains were resistant to ciprofloxacin (MIC90 = 8 microg/ml) and enrofloxacin (MIC90 = 16 microg/ml). The Salmonella Typhimurium strains exhibited 17 and 23% resistance to ciprofloxacin and enrofloxacin, respectively, with an MIC90 of 8 microg/ ml, and these two antibiotics also were active against Salmonella Derby and Salmonella Anatum. Cephalothin, gentamicin, and trimethoprim had limited activity against Salmonella Anatum and Salmonella Schwarzengrund, with MIC90 values of 256 to >512 microg/ml. Cephalothin and gentamicin were moderately active against Salmonella Derby and Salmonella Typhimurium, but 30 to 40% of these strains were resistant to trimethoprim. The Salmonella strains isolated from pork carcasses in Taiwan were relatively resistant to the antimicrobial agents tested, with the exception of ceftriaxone. Although a variety of MIC values were obtained, generally these values were high.     

Control of VOCs emissions by condenser pre-treatment in a semiconductor fab

The performance of a modified design of local condensers to pre-treat a variety of volatile organic compounds (VOCs) emitted from the stripping process of a semiconductor fab was tested in this study. The reaction temperature of the condensers was controlled at around 10 °C, it is relatively higher than the traditional condenser reaction temperature. Both VOCs and water vapors were condensed and formed liquid films. This resulted in an enhancement of the VOCs removals, especially for VOCs of high boiling points or solubility. This can help to prevent the follow up zeolite concentrator from damage. The performance of the integrated system of condenser/zeolite concentrator could, therefore, remain highly efficient for a longer operation time. Its annualized cost would also be lower than installing the zeolite concentrator only.     

Improved Thermoelectric Characteristics of Si-Doped Misfit-Layered Cobaltite

The cobaltite Ca₃Co₄O_9+δ has shown large thermopower and is considered to be a good candidate for use as a thermoelectric material. The composition of Ca₃Co₄O_9+δ is better expressed as [Ca₂CoO₃][CoO₂] _b1/b2 with the misfit-layered structure featuring different periodicities along the b axis, with b ₁ referring to the b-axis length of the NaCl-type [Ca₂CoO₃] sublattice and b ₂ referring to the b-axis length of the [CoO₂] sublattice. The crystal structure of Ca₃Co₄O_9+δ can be viewed as being of two subsystems, i.e., the distorted NaCl-type [Ca₂CoO₃] sublattice and the CdI₂-type [CoO₂] sublattice, alternately stacked along the c-axis. In this paper, we report measurements of the electrical resistivity and Seebeck coefficient for a series of misfit-layered oxides Ca₃Co_4−x Si _x O_9+δ prepared by solid-state reaction. Structural parameters are refined with the superspace group X2/m(0β0)s0 using powder x-ray diffraction data. With partial substitution of Si⁴⁺ for Co³⁺, the resistivity decreases, while the thermopower increases simultaneously. These results indicate that partial substitution of Si⁴⁺ improves the thermoelectric characteristics of Ca₃Co₄O_9+δ .