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We studied the dynamical motion of flux lines in melt-processed Sm-Ba-Cu-O (SmBCO) bulk-superconductors driven by a magnetic pulse at 77 K. The total amount of trapped magnetic flux (T) as a function of the magnitude of pulse exhibited a peak; the decrease of T for large pulses is attributed to the increase in temperature of the sample due to the resistive force exerted on moving flux lines. Compared to melt-processed Y-Ba-Cu-O, it is found that the penetration of flux lines into the sample requires a larger pulse, reflecting the strong pinning effect of SmBCO.

We have studied the magnetization of a melt-processed Sm–Ba–Cu–O bulk superconductor by magnetic pulses at 77 K. The amount of trapped magnetic flux (ΦT) as a function of the pulse amplitude exhibited a peak, which is attributable to the heating of the sample caused by the fast motion of flux lines in the presence of resistive forces. The peak value of ΦT was about half the amount of magnetic flux that was trapped when the sample was field cooled to 77 K, where the field-cooling (FC) value corresponds to the full capability of trapping magnetic flux by the sample. We found that sandwiching the sample with ferromagnetic materials and iteratively applying magnetic pulses while progressively decreasing the amplitude increases the amount of trapped magnetic flux. By combining these two techniques, ΦT increased to about 90% of that of FC magnetization.

Acinar cell cystadenoma (ACA) of the pancreas has been newly recognized as an entity by the World Health Organization (WHO) definition (2010), and its pathogenesis has not been known adequately because of the rarity. Here, we report a case of a 22-year-old female who had been followed up for a cystic lesion at the tail of the pancreas pointed out by a screening computed tomography (CT) scan 7 years ago. The tumor grew in size from 3.3 to 5.1 cm in diameter for 6 years (0.3 cm per year). Particularly, it rapidly grew up to 6.3 cm in the latest 3 months in concurrence with the emergence of epigastralgia. A contrasted CT scan revealed the irregularly formed, multilocular cystic tumor having thin septum and calcification. The intratumoral magnetic resonance imaging intensity in the T1 and T2 weighted images were low and high, respectively. No communications between the tumor and the main pancreatic duct (MPD) were found, but the tumor displaced the MPD. She underwent surgical resection because the tumor was growing, turned symptomatic, and it seemed difficult to be diagnosed correctly until totally biopsied. Spleen-preserved distal pancreatectomy was performed. It was pathologically diagnosed as ACA; the cyst was lined by cells with normal acinar differentiation; cuboidal cells with round, basally oriented nuclei and eosinophilic granules in its apical cytoplasm. The abdominal pain has disappeared, and no recurrences have been found during a 5-year follow-up. Clinicians are recommended to consider an ACA as one of differential diagnoses of cystic tumors of the pancreas to provide appropriate diagnostics and therapeutics.

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