Chiba Institute of Technology

About: Chiba Institute of Technology is a education organization based out in Narashino, Japan. It is known for research contribution in the topics: RNA & Magnet. The organization has 2663 authors who have published 4999 publications receiving 56870 citations. The organization is also known as: Chiba kōgyō daigaku & Kōa Institute of Technology.

Sustainable oleic and stearic acid based biodegradable surfactants

Abstract: Renewable ester functionalized oleic and stearic acid based imidazolium surfactants were synthesized and characterized using spectroscopic techniques. The new surfactants were investigated for their self-aggregation properties and biodegradability in aqueous solution. These fatty acid based surfactants were able to self-aggregate into micelles at lower concentration compared to conventional surfactants and were found to be readily biodegradable. The surface properties and biodegradation rate of these new renewable surfactants depend on the nature of the hydrophobic tail. The oleic acid based surfactant containing a double bond in the hydrophobic oleyl tail demonstrated a greater capability to reduce the surface tension of an aqueous solution along with a greater ability to undergo biodegradation compared to the saturated hydrophobic stearyl tail containing a stearic acid based surfactant.

Production of bulk amorphous and nanocomposite Nd/sub 4/Fe/sub 77.5/B/sub 18.5/ materials by spark plasma sintering method

Abstract: Amorphous melt-spun ribbons of an Nd/sub 4/Fe/sub 77.5/B/sub 18.5/ alloy were consolidated into bulk materials by a spark plasma sintering method. The resultant bulk materials were amorphous when the ribbons were consolidated at 773 K. The amorphous bulk materials showed a low coercivity as expected for amorphous Nd-Fe-B materials. Heat treatment of the bulk materials above the crystallization temperature resulted in the formation of a metastable Fe/sub 3/B phase together with an Nd/sub 2/Fe/sub 14/B phase. The resultant nanocomposite magnets showed a coercivity as high as 2.4 kOe as was the case for the annealed melt-spun ribbons. Such a bulk nanocomposite magnet with a high coercivity could be directly produced by the spark plasma sintering method. The bulk materials consolidated at 873 K consisted of Fe/sub 3/B and Nd/sub 2/Fe/sub 14/B phases and exhibited a high coercivity without heat treatment. The optimally annealed specimen showed a high remanence of 12 kG with the maximum energy product in excess of 10 MGOe.

Personalization of head-related transfer functions in the median plane based on the anthropometry of the listener's pinnaea)

Abstract: A listener's own head-related transfer functions (HRTFs) are required for accurate three-dimensional sound image control. The HRTFs of other listeners often cause front-back confusion and errors in the perception of vertical angles. However, measuring the HRTFs of all listeners for all directions of a sound source is impractical because the measurement requires a special apparatus and a lot of time. The present study proposes a method for estimating the appropriate HRTFs for an individual listener. The proposed method estimates the frequencies of the two lowest spectral notches (N1 and N2), which play an important role in vertical localization, in the HRTF of an individual listener by anthropometry of the listener's pinnae. The best-matching HRTFs, of which N1 and N2 are the closest to the estimates, are then selected from an HRTF database. In order to examine the validity of the proposed method, localization tests in the upper median plane were performed using four subjects. The results revealed that the best-matching HRTFs provided approximately the same performance as the listener's own HRTFs for the target directions of the front and rear for all four subjects. For the upper target directions, however, the performance of the localization for some of the subjects decreased.