Acoustoelastic Axial Stress Measurement of Short Bolts with Longitudinal and Transverse Waves

The bolts used for automobiles are relatively small compared with those used in power plants, steel bridges and frames. The precise control of the fastening force is required for important parts. The force measurement by torque wrenches is, however, unreliable because it does measure the frictional torque caused by the axial force not but axial force itself. Therefore direct measurement of the axial force in those bolts is required. The conventional ultrasonic bolt gages are not applicable for these short bolts because the bolt length uniformly stressed is small compared with the total length. An ultrasonic resonance method [1] is useful for axial stress measurement of these bolts, however, it requires long measurement time because of frequency sweep and both measurements in stressed and unstressed states.</p

Ionic multilayers at the free surface of an ionic liquid, trioctylmethylammonium bis(nonafluorobutanesulfonyl)amide, probed by x-ray reflectivity measurements

The presence of ionic multilayers at the free surface of an ionic liquid, trioctylmethylammonium bis nonafluorobutanesulfonyl amide TOMA+ C4C4N− , extending into the bulk from the surface to the depth of 60 Å has been probed by x-ray reflectivity measurements. The reflectivity versus momentum transfer Q plot shows a broad peak at Q 0.4 Å−1, implying the presence of ionic layers at the TOMA+ C4C4N− surface. The analysis using model fittings revealed that at least four layers are formed with the interlayer distance of 16 Å. TOMA+ and C4C4N− are suggested not to be segregated as alternating cationic and anionic layers at the TOMA+ C4C4N− surface. It is likely that the detection of the ionic multilayers with x-ray reflectivity has been realized by virtue of the greater size of TOMA+ and C4C4N− and the high critical temperature of TOMA+ C4C4N−

Salvage Photodynamic Therapy Using Talaporfin Sodium for Local Failure of Esophageal Squamous Cell Carcinoma

[Background] Talaporfin sodium photodynamic therapy (TS-PDT) for local failure after chemoradiotherapy (CRT) in patients with esophageal squamous cell carcinoma has recently been reported to be highly effective and less invasive, compared to other treatment modalities. TS-PDT was recently introduced at the Tottori University Hospital, Japan. The aim of this study is to clarify the efficacy and safety of PDT in our hospital. [Methods] This was a single-center observational study. We examined eight cases of TS-PDT performed between January 2016 and December 2019. The main endpoints were local complete remission (L-CR) rate and the adverse events. In addition, age, gender, histology, tumor location, TNM stage, tumor depth, irradiation dose, and overall survival (OS) were examined. [Results] The patients included 7 men and a woman, with an average age of 72.1 years (range 63–82 years). The baseline clinical stages before CRT or radiotherapy were stage I in 1, stage II in 3, stage III in 3, and stage IVA in 1 patient. The T stage on endoscopic assessment before TS-PDT was T1 in 6 patients and T2 in 2 patients. Treatment outcomes and adverse events were evaluated. There were no treatment-related deaths, and no significant adverse events occurred intraoperatively or postoperatively. The L-CR rate was 7/8 (87.5%); T1 cases had 100% (6/6) L-CR, while T2 cases had 50% (1/2). The 2-year OS rates were 87%. [Conclusion] TS-PDT was observed to be safe and effective in the first eight cases of its application following its introduction in our hospital

Dual-optical-comb spectroscopic ellipsometry

Spectroscopic ellipsometry is a means to investigate optical and dielectric material responses. Conventional spectroscopic ellipsometry has trade-offs between spectral accuracy, resolution, and measurement time. Polarization modulation has afforded poor performance due to its sensitivity to mechanical vibrational noise, thermal instability, and polarization wavelength dependency. We equip a spectroscopic ellipsometer with dual-optical-comb spectroscopy, viz. dual-optical-comb spectroscopic ellipsometry (DCSE). The DCSE directly and simultaneously obtains amplitude and phase information with ultra-high spectral precision that is beyond the conventional limit. This precision is due to the automatic time-sweeping acquisition of the interferogram using Fourier transform spectroscopy and optical combs with well-defined frequency. Ellipsometric evaluation without polarization modulation also enhances the stability and robustness of the system. In this study, we evaluate the DCSE of birefringent materials and thin films, which showed improved spectral accuracy and a resolution of up to 1.2x10-5 nm across a 5-10 THz spectral bandwidth without any mechanical movement.Comment: 30 pages, 4 figure

Adaptive sampling dual terahertz comb spectroscopy using dual free-running femtosecond lasers

Terahertz (THz) dual comb spectroscopy (DCS) is a promising method for high-accuracy, high-resolution, broadband THz spectroscopy because the mode-resolved THz comb spectrum includes both broadband THz radiation and narrow-line CW-THz radiation characteristics. In addition, all frequency modes of a THz comb can be phase-locked to a microwave frequency standard, providing excellent traceability. However, the need for stabilization of dual femtosecond lasers has often hindered its wide use. To overcome this limitation, here we have demonstrated adaptive-sampling THz-DCS, allowing the use of free-running femtosecond lasers. To correct the fluctuation of the time and frequency scales caused by the laser timing jitter, an adaptive sampling clock is generated by dual THz-comb-referenced spectrum analysers and is used for a timing clock signal in a data acquisition board. The results not only indicated the successful implementation of THz-DCS with free-running lasers but also showed that this configuration outperforms standard THz-DCS with stabilized lasers due to the slight jitter remained in the stabilized lasers

Dual-comb spectroscopic ellipsometry

Spectroscopic ellipsometry is a means of investigating optical and dielectric material responses. Conventional spectroscopic ellipsometry is subject to trade-offs between spectral accuracy, resolution, and measurement time. Polarization modulation has afforded poor performance because of its sensitivity to mechanical vibrational noise, thermal instability, and polarization-wavelength dependency. We combine spectroscopic ellipsometry with dual-comb spectroscopy, namely, dual-comb spectroscopic ellipsometry. Dual-comb spectroscopic ellipsometry (DCSE). DCSE directly and simultaneously obtains the ellipsometric parameters of the amplitude ratio and phase difference between s-polarized and p-polarized light signals with ultra-high spectral resolution and no polarization modulation, beyond the conventional limit. Ellipsometric evaluation without polarization modulation also enhances the stability and robustness of the system. In this study, we construct a polarization-modulation-free DCSE system with a spectral resolution of up to 1.2 × 10−5 nm throughout the spectral range of 1514–1595 nm and achieved an accuracy of 38.4 nm and a precision of 3.3 nm in the measurement of thin-film samples