Development of a charge-carrier drift velocity measurement system in diamonds by using a UV pulse laser

There are continuing efforts of developing faster FETs and diamond is one of the strong candidates as a base semiconductor. Since the upper-limit-frequency of diamond FETs determines saturated drift velocities of charge-carriers, we need to first characterize diamond to develop better FETs. It is, however, not easy to measure the velocities with response time of less than 20 ns. Therefore, we developed a drift velocity measurement system using a time-of-flight (TOF) technique with a UV laser with 100 ps pulse width. In order to realize response times faster than 20 ns, we employed a 50 Ω coaxial cable as a load, with which we could effectively reduce the stray capacitance and inductance, and also, suppress reflections in the signal which gives false signals. As a result, we can measure carrier-transit times shorter than 10 ns.http://www.sciencedirect.com/science/journal/0925963

Development of a TOF measurement system of charge carrier dynamics in diamond thin films using a UV pulsed laser

A fast TOF measurement system with 150 ps time resolution for transport behavior of free charge carriers in an intrinsic diamond film by using a UV pulsed laser was developed. The 213 nm UV laser light narrowed to approximately 80 μm widths could locally create hole–electron pairs in selected locations on a diamond film between two parallel electrodes on the surface. This system measured accurate charge transport characteristics in a diamond film, because created charge carriers moved in a part of the diamond film where they did not get any influence from the laser irradiation. Diamond samples used for verification of the TOF system were intrinsic CVD diamond films with thickness between 4 and 10 μm grown on HP/HT diamond substrates. Transit time of holes for one diamond film was 4.7 ns with a traverse distance of 250 μm. The local irradiation of laser made it possible to measure transport characteristics of electrons and holes separately. In addition, it substantially reduced the influence of photoelectron, because the laser beam did not irradiate electrodes. Through several examinations, excellent reliability of the TOF system was confirmed

Epidemiological profiles of chronic low back and knee pain in middle-aged and elderly Japanese from the Murakami cohort

Akemi Takahashi,1 Kaori Kitamura,2 Yumi Watanabe,2 Ryosaku Kobayashi,3 Toshiko Saito,4 Ribeka Takachi,5 Keiko Kabasawa,6 Rieko Oshiki,1 Shoichiro Tsugane,7 Masayuki Iki,8 Ayako Sasaki,9 Osamu Yamazaki,10 Kazutoshi Nakamura2 1Department of Rehabilitation, Niigata University of Rehabilitation, Niigata, Japan; 2Division of Preventive Medicine, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan; 3Department of Physical Therapy, Niigata University of Health and Welfare, Niigata, Japan; 4Department of Health and Nutrition, Niigata University of Health and Welfare, Niigata, Japan; 5Department of Food Science and Nutrition, Nara Women’s University Graduate School of Humanities and Sciences, Nara, Japan; 6Department of Health Promotion Medicine, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan; 7Center for Public Health Sciences, National Cancer Center, Tokyo, Japan; 8Department of Public Health, Kindai University Faculty of Medicine, Osaka, Japan; 9Murakami Public Health Center, Niigata, Japan; 10Niigata Prefectural Office, Niigata, Japan Purpose: Epidemiological profiles of chronic low back and knee pain have not been studied extensively. This study aimed to determine the prevalence of and potential risk factors associated with chronic low back and knee pain in middle-aged and elderly Japanese. Methods: This cross-sectional study involved 14,217 community-dwelling individuals aged 40–74 years living in the Murakami area of Japan. A self-administered questionnaire was used to obtain information regarding marital status, education level, occupation, household income, and body size. Participants also reported current chronic pain, if any, by site and degree of severity, using the verbal rating scale of the Short Form 36. Results: The prevalence of moderate–very severe chronic pain was 9.7% in the low back, 6.7% in the knee, 13.9% in either the low back or knee, and 2.6% in both the low back and knee. Multivariate analysis revealed that lower education level, lower income, and manual occupation in men and older age and higher body mass index in women were significantly associated with a higher prevalence of chronic low back pain. In both sexes, older age, lower education level, and higher body mass index were significantly associated with a higher prevalence of knee pain. Regarding sex differences, adjusted ORs of chronic pain of the low back and knee for women were 0.85 (95% CI 0.75–0.97) and 1.27 (95% CI 1.09–1.49), respectively. Conclusion: Nearly 14% of middle-aged and elderly individuals had moderate–very severe chronic pain of the low back or knee, and this pain was associated with many demographic factors, including sex, age, education level, household income, occupation, and body size. Keywords: body mass index, chronic pain, demography, knee pain, low back pain, prevalenc