Metal atomic contact under electrochemical potential control

Electric conductance of the metal atomic contacts of Au and Pd was investigated using a scanning tunneling microscope (STM) in solution under electrochemical potential control. At the hydrogen evolution potential, a fractional conductance peak appeared around 0.5 G(0) (G(0) = 2e(2)/h) in the conductance histograms of Au contacts. For Pd contacts, peaks appeared around 1.0 G(0) in the conductance histograms at the hydrogen evolution potential. The conductance behavior and atomic configuration of the metal atomic contacts at hydrogen evolution potential were discussed based on previously reported experimental results and theoretical calculation results. We have proposed the formation of hydrogen adsorbed metal Au and Pd contacts in solution at the hydrogen evolution potential.     

Read/write characteristics of a new type of bit-patterned-media using nano-patterned glassy alloy

The paper reports a feasibility study of new type bit-patterned-media using a nano-patterned glassy alloy template for ultra-high density hard disk applications. The prototype bit-patterned-media was prepared using a nano-hole array pattern fabricated on a Pd-based glassy alloy thin film and a Co/Pd multilayered film filled in the nano-holes. The prepared prototype bit-patterned-media had a smooth surface and isolated Co/Pd multilayer magnetic dots, where the average dot diameter, the average dot pitch and the average dot height were 30, 60 and 19 nm, respectively. MFM (magnetic force microscope) observation revealed that each dot was magnetized in a perpendicular direction and the magnetization could reverse when an opposite magnetic field was applied. Static read/write tester measurements showed that repeated writing and reading on isolated magnetic dots were possible in combination with conventional magnetic heads and high-accuracy positioning technologies. The present study indicates that the new type of bit-patterned-media composed of nano-hole arrays fabricated on glassy alloy film template and Co/Pd multilayer magnetic dots are promising for applications to next generation ultra-high density hard disk drives.     

Glass formation, physico-chemical properties, and structure of glasses based on Ga2S3-GeS2-Sb2S3 system

We prepared sulfide glasses based on a Ga₂S₃-GeS₂-Sb₂S₃ system and investigated the compositional dependences of their physico-chemical properties and structure. Additivities were observed for density and refractive index; i.e., these properties were presented by the summation of the contribution from each component. With the increase of Sb₂S₃ content, the density, refractive index, and thermal expansion coefficient increased while the glass transition and softening temperatures decreased, and the short-wavelength absorption edge shifted to the longer wavelength side. These variations are expected from the incorporation of a heavy element (Sb) into the glasses. On the other hand, the replacement of GeS₂ by Ga₂S₃ increased the density and refractive index, and shifted the short-wavelength absorption edge to the longer wavelength side. These variations were explained by the increase of the number densities of the cations with the replacement and the formation of metal-metal bonds. The latter was confirmed from the Raman spectra. We also investigated the effects of Ag₂S incorporation on the optical properties. The incorporation of Ag₂S increased the density and refractive index whereas the position of the short-wavelength absorption edge varied little. These results show the possibility of fabricating an optical waveguide by Ag incorporation into the glasses.     

Influence of ZIF-8 modification on performance of ZnO-based dye-sensitized solar cells

Journal of Solid State Electrochemistry - Metal–organic frameworks (MOFs) were used to modify the surface of nanoparticulate ZnO electrodes, aiming at enhancing the performance of...     

Evaluation of the accuracy of hTERT gene aberrant methylation using electrochemical hybridization assay and liquid-based cytology in screening for oral squamous cell carcinoma

In order to improve the survival rate of oral squamous cell carcinoma (OSCC) patients, a reliable diagnostic method for early OSCC detection is required that is minimally invasive, less burdensome to the patient, and has high sensitivity and specificity. Therefore, we performed the detection of abnormal methylation at three locations in the hTERT promoter region of oral exfoliated cells by employing the ferrocenylnaphthalene diimide (FND)-based electrochemical hybridization assay (FND-EHA) using three types of DNA probe-immobilized electrodes. We also performed liquid cytology using oral exfoliated cells and compared these obtained data to evaluate whether FND- EHA can be used as an OSCC screening system. The results showed a good correlation between this method and conventional OSCC screening, and cytology. In addition, FND-EHA was also able to determine samples that had been ambiguously determined by liquid cytology. This indicates that FND-EHA may be useful as an OSCC screening system.