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.

Bio-based thermosetting bismaleimide resins using eugenol, bieugenol and eugenol novolac

Abstract: 5,5′-Bieugenol (BEG) and eugenol novolac (EGN) were synthesized by the oxidative coupling reaction of eugenol (EG) and the addition–condensation reaction of EG with formaldehyde, respectively. The EG, BEG and EGN were prepolymerized with 4,4′-bismaleimidediphenylmethane (BMI) at 180 °C and then compression-molded at finally 250 °C for 6 h to produce cured EG/BMI (EB), BEG/BMI (BB) and EGN/BMI (NB) resins with eugenol/maleimide unit ratios of 1/1, 1/2 and 1/3. The FT-IR analysis of EBs and 13C NMR analysis of the model reaction product of EG/N-phenylmaleimide (PMI) 1/3 at 200 °C for 12 h suggested that the ene reaction and subsequent Diels-Alder/ene reactions mainly occurred for EBs. The FT-IR analyses of BBs and NBs supported the occurrence of ene reaction and subsequent thermal addition copolymerization in a similar manner to the well-known curing reaction of 2,2′-diallylbisphenol A and BMI. The glass transition temperature (Tg) and 5% weight loss temperature (T5) of the cured resin increased with increasing BMI content, and EB 1/3 showed the highest Tg 377 °C and T5 475 °C. The flexural strengths and moduli of EBs and NBs were higher than those of BBs, and EB 1/2 showed the most balanced flexural strength and modulus (84.5 MPa and 2.75 GPa). The FE-SEM analysis revealed that there is no phase separation for all the cured resins.

A Novel Rotor Design of Interior Permanent-Magnet Synchronous Motors to Cope with Both Maximum Torque and Iron-Loss Reduction

Abstract: A novel rotor design of interior permanent-magnet synchronous motors (IPMSMs) has been developed in order to cope with both maximum torque and iron-loss reduction for wide-speed-range applications. First, the flux barrier and permanent-magnet shapes of an IPMSM are determined by using an automatic optimization method. In this optimization, the iron loss of the IPMSM under flux-weakening control at high speeds is minimized under the constrained condition of maximum torque at low speeds. As a result, a novel rotor, which has inner magnetic pole bodies, is obtained. The effectiveness of this design is discussed from both results of the finite-element analysis (FEA) and the measurement of a prototype motor. It is revealed that the iron loss of the proposed IPMSM at high speeds is significantly reduced, whereas the maximum torque decreases by only a few percent.

Laser speckle velocimeter using self-mixing laser diode

Abstract: We have built a novel laser speckle velocimeter using a self-mixing laser diode (SM-LD). The speckle signal obtained by the measurement system has a waveform independent of the target velocity when the same path on the target surface is iteratively measured. The mean frequency of the speckle signal is directly proportional to the target velocity when the laser beam spot diameter is kept constant, and greater than 0.36 mm. The mean speckle signal frequency is automatically measured by using a computer. Its measurement error is inversely proportional to the scanned length, and is 2% for 100 mm. It is possible to detect velocity of the target transversely moving across the laser light beam using this compact measuring system.