Fabrication of microtubular reactors coated with thin catalytic layer (M=Pd,Pd−Cu,Pt, Rh,Au)

Novel micro tubular reactors composed of Inconel 625 support, TiO₂/Ti intermediate layer and thin catalytic metal film (Pd, Pd−Cu alloy, Pt, Rh, and Au) were fabricated by continuous electroless plating technique. The reactors withstood high temperature (400 °C) and high pressure (30 MPa) water flow without loss of catalytic metals. The high catalytic efficiency of the reactors was demonstrated by the rapid and complete decomposition of organic dye in the flow system.     

Effect of the Y2O3 Concentration in YSZ on the Thermophysical Property as a Thermal Shielding Material

The effect of the Y₂O₃ concentration in yttria-stabilized zirconia (YSZ) on the thermophysical property of porous YSZ was studied. The specific heat capacities (C_p), the thermal diffusivity (α), the apparent density (ρ) of a 3 mol% Y₂O₃/97 mol% ZrO₂ (3YSZ), and an 8 mol% Y₂O₃/97 mol% ZrO₂ (8YSZ) were measured. The 8YSZ's C_p was lower than that of the 3YSZ. When the YSZs were dense, the 3YSZ's α value by a phonon decreased with an increase in the temperature, whereas that of the 8YSZ was almost constant over a wide temperature range. When the YSZs were porous, the 8YSZ's α value by the phonon was greater than that of the 3YSZ's.     

Energy-efficient coal dewatering using liquefied dimethyl ether

In this study, we dewatered sub-bituminous coal mined in Warra, Indonesia, by using liquefied dimethyl ether (DME); no heating was required in this dewatering process. We achieved this dewatering both in a laboratory-scale experiment and using previously developed bench-scale equipment. We also examined the properties of the coal before and after dewatering and measured the amount of energy required by the equipment. We found that the maximum water extraction efficiency of liquefied DME was 98.3%. Further, the properties of the coal did not change after the dewatering treatment. The wastewater obtained by dewatering can be treated by existing wastewater treatment technologies. The energy consumed by the bench-scale equipment was 2069 kJ/kg-water; thus, this dewatering process using liquefied DME was confirmed to be effective and energy efficient.     

Thinned wafer multi-stack 3DI technology

Wafer scale 3DI technology, so-called wafer-on-a-wafer (WOW), characterized by thinned-wafer stacking and Cu multi-level interconnects, has been developed, and revealed that seven-level multi-wafer stacking is possible. The WOW process differs from the chip-on-a-chip and chip-on-a-wafer processes and can be used for wafer-scale bulk processes, enabling manufacturing from transistor to 3D stacking using wafers. Wafers are thinned down to 20-μm and bonded to the base wafer following back-to-face stacking. Through-silicon-via (TSV) holes with a diameter of 30 μm are formed and etched-off until the lower electrode of Au which is patterned on the underneath wafer. Titanium (Ti) and titanium-nitride (TiN) are formed on a TSV hole as a barrier metal and electrode for the electrochemically plated Cu (ECP-Cu). After ECP-Cu deposition, surface planarization is performed using Surface Planer™. Those wafers are used as a base wafer and multi-stacking is carried out repeatedly. The vertical connection between Cu of TSV and Au is therefore connected with a self-aligned contact and without a bump electrode. The electrical properties of the 242-chain contacts within the wafer were measured and no open failure was found. Adopting the thinned substrates eliminates deep silicon etching, and TSV filling which take a long process time, and reduces the residual stress on the Cu plug. Wafers can be stacked as much as possible in accordance with the degree of integration, and this is expected to be a low-cost and high-integration technology for post-scaling.     

Direct polymer-transfer lithography for high-throughput fabrication of Cu line patterns

A novel direct polymer-transfer lithography (DPTL) technique is proposed for fabricating fine patterns having feature sizes ranging from ten to several tens of micrometers with extremely high throughput. By means of this technique, a homemade fluorine-containing polymer “ink”, which has good water repellency, was imprinted directly onto a Cu/polyimide sheet by using an elastomeric polydimethylsiloxane (PDMS) stamp; imprinting was followed by wet etching of the Cu layer, with the transferred polymer patterns serving as an etch mask. Under the optimized imprinting conditions, Cu lead patterns with a minimum line width of approximately 10 μm were successfully fabricated with high accuracy and good reproducibility. The DPTL technique will be very useful for manufacturing flexible printed circuit boards (FPCs).     

Rapid Hydrogenation of Aromatic Nitro Compounds in Supercritical Carbon Dioxide: Mechanistic Implications via Experimental and Theoretical Investigations

An exceptionally rapid hydrogenation of nitrobenzene to aniline [TOF=252,000 h⁻¹] over palladium containing MCM‐41 (Pd/MCM‐41) with excellent yield of >99% can be achieved in supercritical carbon dioxide at 50 °C and a hydrogen pressure of 2.5 MPa. It has been observed that this promising method preferred a single phase between liquid substrate and carbon dioxide‐hydrogen system. The ascendancy of the supercritical carbon dioxide medium is established in comparison with the conventional organic solvent and solvent‐less conditions. Changes in the reaction parameters such as carbon dioxide and hydrogen pressure, temperature and the reaction time do not affect the selectivity. A combined experimental and theoretical study has elucidated the mechanism under the studied reaction condition because experimental observations revealed a direct conversion of nitrobenzene to aniline. However, density functional theory (DFT) calculation shows that the direct conversion is energetically unfavourable; hence, a stepwise mechanism has been proposed. Theoretical predictions and experimental observations suggested that the rate‐limiting step of nitrobenzene conversion is different from that of the liquid phase hydrogenation. This catalytic process can also be successfully extended to the hydrogenation of other aromatic nitro compounds with different substituents. Easy separation of the liquid product from catalyst and the use of an environmentally friendly solvent make this procedure a viable and an attractive green chemical process.     

The parameters evaluation and optimization of polycrystalline diamond micro-electrodischarge machining assisted by electrode tool vibration

The objective of this research is to evaluate and optimize machining parameter of tool electrode vibration on micro-electric discharge machining of polycrystalline diamond. The machining parameters evaluated are charge voltage, capacitance, and vibration of the tool electrode. An orthogonal array, signal-to-noise ratio, and analysis of variance are employed to analyze the effect of these machining parameters. The results show that by application of vibration on tool electrode in machining of polycrystalline diamond, it has significant effect up to 66.48% in increasing material removal rate without increasing surface roughness and tool electrode wear. Using Taguchi method for design of experiment, other significant effects on surface quality and tool electrode wear are also investigated. The results also show that surface roughness is mostly affected by the amount of capacitance (52.24%), and the tool electrode wear is also affected by the amount of capacitance (92.82%).     

Direct encapsulation of proteins into calcium silicate microparticles by water/oil/water interfacial reaction method and their responsive release behaviors

The direct encapsulations of proteins such as lysozyme, bovine serum albumin (BSA) and ovalbumin into calcium silicate microparticles were examined by interfacial reaction method using water/oil/water emulsion (W/O/W emulsion), which was effective for the preparations of silica and calcium carbonate microcapsules encapsulating biomacromolecules. Those proteins added to the sodium silicate solution of the W/O/W emulsion were successfully encapsulated into the microparticles, which were ascertained by diffuse reflectance ultraviolet (UV) and infrared spectra. The encapsulation efficiency of the proteins depended on the molecular weight of proteins, which were also observable in the protein encapsulations into silica and calcium carbonate microcapsules. No discharge of encapsulated proteins by simple washing with deionized water indicated the secure packing of proteins into calcium silicate matrix. Ethylenediamine-N,N,N′,N′-tetraacetic acid, tetrasodium salt (EDTA·4Na) effectively extracted calcium ions from the microparticles to serve as a trigger for the release of proteins, indicating that the elimination of calcium ion initiated the discharge of encapsulated proteins. The ion exchange between calcium and sodium ions also achieved the release of proteins into aqueous solutions. The release rate of proteins such as lysozyme and BSA increased with the concentration of sodium chloride less than 1 M. In diluted solutions, potassium chloride accelerated the protein release more than sodium chloride. These characteristic release behaviors must be applied to drug delivery systems that respond to the concentration of alkaline ions in body fluid.