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Recently, there have been increasing demands not only for the conventional profile surface roughness measurements using atomic force microscopes (AFM) but also for areal surface roughness measurements. In this study, a technique using Sal, one of the areal surface roughness parameters, instead of RSm, one of the profile roughness parameters, is proposed in order to extend the conventional method of profile roughness measurements specified in ISO 19606:2017 to areal roughness measurements. Areal surface roughness measurements performed using a metrological AFM and evaluation of their expanded uncertainties are also reported.

Various aryl-substituted purine derivatives were synthesized through the direct arylation of halopurines with aromatic compounds, facilitated by the combination of triflic acid and fluoroalcohol. This metal-free method is complementary to conventional coupling reactions using metal catalysts and reagents for the syntheses of aryl-substituted purine analogues.

Abstract Objective This study aimed to identify the recurrence rate of genetic generalized epilepsy (GGE) and risk factors for recurrence after antiseizure medication (ASM) withdrawal in adolescent patients. Methods We retrospectively reviewed medical records of patients with GGE who were included in the registry at the Department of Child Neurology, National Hospital Organization Nishiniigata Chuo Hospital from 2000 through 2020. The eligibility criteria were as follows: onset of epileptic seizures at

A known fundamental issue with atomic force microscopy (AFM) is that drift occurs during an AFM measurement, distorting the AFM image. In this study, a method for correcting this nonlinear drift in two dimensions (the vertical axis and one of the two horizontal axes) is proposed and demonstrated. A normal AFM measurement is accomplished with many fast-scan profiles, using the raster scan method. In the proposed drift-correction method, the first-scanned profile is set as the reference profile, and the scan at the first-scanned location is inserted periodically during the normal profile scans. The normal scanned profiles are used to construct a normal AFM image, which is distorted by the drift. The time-dependent drift distance can be estimated by a series of the scanned reference profiles, and the distorted AFM image is corrected using this estimated distance. It is shown, experimentally, that the drift correction in two dimensions has both high resolution and repeatability at the sub-nanometer scale. [ABSTRACT FROM AUTHOR]

The linewidth or critical dimension (CD) of a nanoscale line pattern is calibrated using a metrological atomic force microscope with a tip-tilting mechanism (tilting-mAFM). The tilting tip permits the scanning of the line pattern’s vertical sidewalls. The tilting-mAFM performs two measurements on each side of the line pattern, and two datasets are stitched together to reconstruct the complete shape of the line pattern. Further, the CD is measured based on this pattern. A linewidth standard with a subnanometer-scale uncertainty was used as a target sample to verify this CD calibration procedure. The calibrated CD using the tilting-mAFM was 111.2 nm with an expanded uncertainty of 1.0 nm, which was the smallest uncertainty that was observed among the CD measurements that were reported using the tilting-AFM instruments. Further, the difference between this CD value and the reference CD was only 0.2 nm. The results reveal that the tilting-mAFM can be used for CD metrology with single-nanometer accuracy. [ABSTRACT FROM AUTHOR]

A metrological atomic force microscope with a tip-tilting mechanism (tilting-mAFM) has been developed to expand the capabilities of 3D nanometrology, particularly for high-resolution topography measurements at the surfaces of vertical sidewalls and for traceable measurements of nanodevice linewidth. In the tilting-mAFM, the probe tip is tilted from vertical to 16° at maximum such that the probe tip can touch and trace the vertical sidewall of a nanometer-scale structure; the probe of a conventional atomic force microscope cannot reach the vertical surface because of its finite cone angle. Probe displacement is monitored in three axes by using high-resolution laser interferometry, which is traceable to the SI unit of length. A central-symmetric 3D scanner with a parallel spring structure allows probe scanning with extremely low interaxial crosstalk. A unique technique for scanning vertical sidewalls was also developed and applied. The experimental results indicated high repeatability in the scanned profiles and sidewall angle measurements. Moreover, the 3D measurement of a line pattern was demonstrated, and the data from both sidewalls were successfully stitched together with subnanometer accuracy. Finally, the critical dimension of the line pattern was obtained. [ABSTRACT FROM AUTHOR]

The long-term stability of NEXCERA™ ceramics having a low coefficient of thermal expansion was evaluated over a period of eight years. Several gauge blocks of differing lengths were prepared, using two types of NEXCERA. Each gauge block was kept wrung to a platen and its absolute length was periodically measured by gauge block interferometer during the eight years. Relative uncertainties of measurement of changes in gauge block length were estimated as 4.1  ×  10−8 and 2.9  ×  10−8 for 200 mm and 800 mm gauge blocks, respectively. The experimental results show the trend of expansion and a relative change of less than 0.1  ×  10−6/year for every gauge block. [ABSTRACT FROM AUTHOR]