863 research outputs found

    Learn from history : Lessons from early modern Japanese physics experiment textbooks

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    The aim of our study is to explore the early history of the education of physics experiments in the Meiji era of Japan (1868 - 1912). In this paper, we examine three Japanese physics experiment textbooks which were published during 1880s. One characteristic feature is that the most of the experiments could be performed using simple handmade apparatuses. We consider what can be learned from the ingenuity of physics education pioneers of the late 19th century

    Microcirculation changes in gingival tissue after ultrasonic tooth preparation in beagle dog

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    Abstract: Ultrasonic wave technology is widely used during dental treatments. We previously demonstrated that this method protects the gingival tissue. However, the physiological change on the gingival microvasculature caused by this method remains unclear. Objective: The aim of this study was to investigate the relationship between the morphological and physiological effects on gingival microcirculation when preparing teeth, using the conventional dental turbine or ultrasonic method. Methodology: The lower premolar teeth of beagle dogs were prepared along the gingival margin by using a dental turbine or ultrasonic wave instrument. Gingival vasculature changes were investigated using scanning electron microscopy for corrosion resin casts. Gingival blood flow at the preparation site was determined simultaneously by laser Doppler flowmetry. These assessments were performed immediately (Day 0), at 7 days and 30 days after tooth preparation. Results: At day 0, in the turbine group, blood vessels were destroyed and some resin leaked. Furthermore, gingival blood flow at the site was significantly increased. In contrast, the ultrasonic group demonstrated nearly normal vasculature and gingival blood flow similar to the non-prepared group for 30 days after preparation. No significant alterations occurred in gingival circulation 30 days after either preparation; however, the turbine group revealed obvious morphological changes. Conclusions: Based on multiple approach analyses, this study demonstrated that ultrasonic waves are useful for microvascular protection in tooth preparation. Compared with a dental turbine, ultrasonic wave instruments caused minimal damage to gingival microcirculation. Tooth preparation using ultrasonic wave instruments could be valuable for protecting periodontal tissue

    Japanese Physicist Makita Goto and Simple Experiments

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    In Situ Transmission Electron Microscopy for Electronics

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    Electronic devices are strongly influenced by their microstructures. In situ transmission electron microscopy (in situ TEM) with capability to measure electrical properties is an effective method to dynamically correlate electric properties with microstructures. We have developed tools and in situ TEM experimental procedures for measuring electronic devices, including TEM sample holders and sample preparation methods. The method was used to study metallic nanowire by electromigration, magnetoresistance of a ferromagnetic device, conductance quantization of a metallic nanowire, single electron tunnelling, and operation details of resistive random access memories (ReRAM)

    Quantitative Estimate of CO2 Emission Reduction from Reuse of Automobile Parts in Japan

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    In general, reusing automobile parts reduces not only the cost of replacing the failed parts but also the environmental load of manufacturing new parts. However, these effects have not yet been quantified. The present study focuses on determining the emitted CO2 during production and quantitatively evaluating its reduction by the reuse of automobile parts. First, CO2 emissions are calculated during the reused parts production process at the factory site. Thirty-nine automobiles from 27 models prepared in Japan are examined to measure the amount of CO2 emitted in the production of new parts. Furthermore, the CO2 emission reduction effect for different automobile models is estimated through multiple regression analysis. The CO2 emissions are assumed to be the objective variable, whereas the explanatory variables are derived from the data provided in the automobile inspection certificates. The presented quantitative estimate of CO2 emission reduction owing to the exploitation of reused parts is expected to promote policies for further reducing CO2 emissions and arouse public awareness regarding the benefits of recycling automobile parts
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