Conventional supported Pt catalysts have often been prepared by loading Pt onto commercial supports, such as SiO2, TiO2, Al2O3, and carbon. These catalysts usually have simple metal-support (i.e., Pt-SiO2) interfaces. To tune the catalytic performance of supported Pt catalysts, it is desirable to modify the metal-support interfaces by incorporating an oxide additive into the catalyst formula. H...

Waveguide SIS mixers are presented in which Nb/Al-AlOx/Nb tunnel junctions are integrated with both NbTiN/SiO2/NbTiN and NbTiN/SiO2/Al tuning circuits. The mixers with a NbTiN/SiO2/NbTiN tuning circuit yield relatively low receiver noise temperatures between 700 and 830 GHz, but their sensitivity drops significantly above ~ 850 GHz. In contrast, low-noise heterodyne mixing near 1 THz is observe...

In this article, I will discuss the optical properties of SiO2-nanoparticles that we have investigated recently by photoluminescence (PL) spectroscopy. In particular, I will show the blue-shifts of PL, originating from the electron-hole recombination of the self-trapped exciton (STE), observed in smaller-sized SiO2-nanoparticles. To explain the size effect in relating to the STE PL shift, a que...

Nanocrystal HZSM-5 zeolite aggregates with different SiO2/Al2O3 molar ratios were prepared under low temperature and were used to catalyze the conversion of methanol to propylene and butene. The coke location, coke content, and coke species deposited on HZSM-5 aggregates were investigated. The near-graphite carbon on the external surface of HZSM-5 zeolite (SiO2/Al2O3 molar ratio = 400) was dist...

SiO2/high-κ dielectric stack is a candidate for replacing the conventional SiO2-based dielectric stacks for future Flash memory cells. Electron traps in the high-κ layer can limit the memory retention via the trap-assisted tunneling, and there is a pressing need for their characterization. A new two-pulse C–V measurement technique is developed in this letter, which, for the first time, allows u...

Protein aggregation is a problem in biotechnology. High temperature is one of the most important reasons to enhance enzyme inactivation and aggregation in industrial systems. This work focuses on the effect of TiO2 and SiO2 nanoparticles on refolding and reactivation of lysozyme. In the presence of TiO2 and SiO2 nanoparticles, after enzyme heat treatment at 98C for 30 min, not only aggregates w...

The doping effects of Al2O3 on SiO2 ( -cristobalite) have been studied by first principles calculations, with emphasis on the structural, electronic and optical properties. Compared to pure SiO2 crystal, the electronic density of states (DOS) of the Al2O3 doped SiO2 show significant changes. The electron energy states corresponding to the newly emerged sharp DOS peaks are found to exhibit local...

This paper reports the fabrication of a novel microsensor structure using inductively coupled plasma source (ICP) dry etching process. The novel sensor is based on a SiO2/Si/SU-8 trilayered microcoil/microspring structure. The diameter of the microcoil was approximately 600 m. The ICP process and SU-8 exposing time are discussed. The SiO2 layer can be conveniently modified according to typical ...

Binary SiO2/TiO2 and SiO2/Fe2O3 nanoparticle (diameter < 100 nm) aerosols of varying mole ratios of Ti or Fe to Si were generated in a premixed Bunsen-type aerosol flame reactor. The distribution of species within the particles was investigated using transmission electron microscopy, electron energy loss spectrometry, x-ray diffraction, and Fourier transform infrared spectroscopy. Phase segrega...

Complex engineered nanomaterials (CENs) are a rapidly developing class of structurally and compositionally complex materials that are expected to dominate the next generation of functional nanomaterials. The development of methods enabling rapid assessment of the toxicity risk associated with this type of nanomaterial is therefore critically important. We evaluated the toxicity of three differe...