Publications by authors named "Hirokazu Hashizume"
Article Synopsis
- * The new method enhances mirror production by addressing issues like corrosion and thermal deformation, providing better stability and performance for high-quality x-ray optics.
- * A vacuum degassing technique was developed to reduce bubble pit formation during fabrication, resulting in the successful creation of three pit-free mirrors for the FOXSI-4 project, with precise accuracy and performance comparable to leading x-ray missions.
In this study, figure correction of a master mandrel of a Wolter mirror by organic abrasive machining (OAM) was demonstrated. In OAM, a flow of slurry, dispersed with organic particles, locally removes the surface of a workpiece in contact with a rotating machining tool. A computer-controlled machining system was used to perform the selective removal of a fused silica surface at a spatial resolution of 200 µm.
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- The Wolter mirror is a high-performance optical device designed for focusing soft x-rays to a very small spot size, with benefits like high efficiency and resilience against alignment errors.
- The study overcame challenges in creating this mirror by using tactile scanning measurements, which allowed for accurate surface characterization without damaging the mirror substrate.
- The final fabricated Wolter mirror showed minimal figure error, and simulations confirmed its ability to focus x-ray beams as expected, with experimental results validating the tactile measurement approach's effectiveness.
High-precision optics for short-wavelength regions, such as x rays and extreme ultraviolet light, generally require nanometer-level figure accuracy on their surfaces. Such optics are finished via a numerically controlled figure correction process in which the dwelling time of the machining tool on the workpiece is controlled. Due to the limitation of the machined spot size, it is difficult to remove mid-spatial-frequency (1 to 10 mm) errors on an optical surface.
View Article and Find Full Text PDF'Harimaru' is a new potato variety bred from a cross between 'Saikai 35' as a female parent and 'Pike' as a male parent. Marker selection was performed for 1,647 seedlings to combine resistance genes to late blight (), ( ), (), and golden cyst nematode (). In total, 194 selected clones were evaluated in the field, among which the best clone was officially released as 'Harimaru'.
View Article and Find Full Text PDFFour chiral forms of the beta-lactone DU-6622 (3-hydroxy-2-(hydroxymethyl)-5-[7-(methoxycarbonyl)naphthalen-1-yl]pentanoic acid 1,3-lactone) were prepared to investigate their inhibitory activity against 3-hydroxy-3-methylglutarly-CoA (HMG-CoA) synthase. The (2R,3R)-beta-lactone isomer (+)-8a, having the same stereochemistry as that of the fungal beta-lactone 1233A, showed the most potent HMG-CoA synthase inhibitory activity (IC(50): 0.098 &mgr;M).
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