Low-Temperature Characteristics of an AlN/Diamond Surface Acoustic Wave Resonator

Phonons confined in mechanical resonators can be coupled to a variety of quantum systems and are expected to be applied to hybrid quantum systems. Diamond surface acoustic wave (SAW) devices are capable of high efficiency in phonon interaction with color centers in diamond. The temperature dependence of the quality factor is crucial for inferring the governing mechanism of coupling efficiency between phonons and color centers in diamond. In this paper, we report on the temperature dependence of the quality factor of an AlN/diamond SAW device from room temperature to 5 K. The temperature dependence of the quality factor and resonant frequency suggests that the mechanism of SAW dissipation in the AlN/diamond SAW resonator at 5 GHz is the phonon-phonon scattering in the Akheiser region, and that further cooling can be expected to improve the quality factor. This result provides a crucial guideline for the future design of AlN/diamond SAW devices.Comment: 10 pages, 5 figure

Coherent Electric-Field Control of Orbital state in a Neutral Nitrogen-Vacancy Center

The coherent control of the orbital state is crucial for color centers in diamonds for realizing extremely low-power manipulation. Here, we propose the neutrally charged nitrogen-vacancy center, NV$^0$, as an ideal system for orbital control through electric fields. We estimate electric susceptibility in the ground state of NV$^0$ to be comparable to that in the excited state of NV$^-$. Also, we demonstrate coherent control of the orbital states of NV$^0$. The required power for orbital control is three orders of magnitude smaller than that for spin control, highlighting the potential for interfacing a superconducting qubit operated in a dilution refrigerator.Comment: 12 pages, 6 figure

High-efficiency planarization method combining mechanical polishing and atmospheric-pressure plasma etching for hard-to-machine semiconductor substrates

A high-efficiency planarization technique for preprocessing before final polishing is needed for hard-to-machine wide-band-gap semiconductors, such as silicon carbide (SiC), gallium nitride, and diamond. We proposed a novel planarization method that combines chemical mechanical polishing (CMP) and atmospheric-pressure plasma etching (plasma chemical vaporization machining [P-CVM]) and developed a prototype of the basic type CMP/P-CVM combined processing system. This prototype has a mechanical polishing part for introducing a damaged layer on the convex part of the sample surface and a P-CVM part for efficient etching of the damaged layer. Process conditions for plasma generation were determined in order to minimize the optical emission intensity ratio of nitrogen to helium because nitrogen comes from circumstance air and should not exist in the plasma region. Process conditions for mechanical polishing were determined in order to efficiently generate a damaged layer only on the convex part of the sample surface. The combined process was performed using a SiC substrate on which the mesa structure was fabricated as a sample. As a result, we found that the convex parts of the mesa structure were preferentially removed and the surface of the sample was planarized. We also found that the decreasing rate of the peak-to-valley value of the mesa structure obtained by CMP/P-CVM combined processing was approximately seven times greater than that during mechanical polishing.Yasuhisa SANO, Kousuke SHIOZAWA, Toshiro DOI, Syuhei KUROKAWA, Hideo AIDA, Tadakazu MIYASHITA, Kazuto YAMAUCHI, High-efficiency planarization method combining mechanical polishing and atmospheric-pressure plasma etching for hard-to-machine semiconductor substrates, Mechanical Engineering Journal, 2016, 3(1), 15-00527, https://doi.org/10.1299/mej.15-00527

Exocytotic features of rat specific atrial granules.

To clarify the mode of secretion of specific atrial granules, rat atrial muscle cells were examined by transmission electron microscopy. Atrial granule formation and exocytotic features of granules were clearly seen. Abrupt breaks in the unit membrane structure of mature granules were observed in thin sections, but these breaks were not detected in freeze-fracture replicas. These findings support the concept that the granule contents are released to the extracellular space by exocytosis.</p

Influence of Heat-affected Sea Coal on Green Sand

The characteristic of green sand changes as it is heated by pouring. Then, after experimental repeated pouring, the green sand composition, and its properties were measured, and the penetration defect caused in a test casting was detected. As a result, it became evident that the sea coal in green sand changed the condition by the heat influence. That is, the sea coal powder changed to adhere to sand surface as the total clay removal. After heating, the oolitics increased, the specimen density increased, and the scabbing time decreased. The penetration defect became difficult to occur when volatile matter in sea coal was more and ash in sea coal was less

Electon microscopic study of atrial specific granules in relation to soudium and water metabolism

The function of atrial specific granules has been obscure in spite of many morphological studies. However, the relationship between these granules and sodium and water metabolism has been suggested, and it has been confirmed that heart atrium extract has a diuretic action. An atrial natriuretic peptide (ANP) has been purified from the human atrium. The author investigated the kinetics of specific granules and discussed the relationship between these granules and ANP. A detailed study on the mechanism of secretion of these granules was also performed. The number of atrial specific granules in rats fed at 5℃ for 50 days tended to decrease, and number in rats fed at 33℃ for 50 days increased. The number of granules in rats fed with 0.5-1% sodium chloride solution decreased after 45 days. An increase in the number of granules was observed after rats were fed without water 11 days. This increase in granules was observed in the sarcoplasm between myofibrils, and just beneath the plasma membrane as well as in the sarcoplasm at the periphery the nucleus. The continuous administration of diurtics (Lunetron) induced a decrease in granules at the periphery of the nucleus, while antidiuretics (Pitrssin) caused an increase in granules around the nucleus, between myofibrils and beneath the plasma membrane. Type Ⅱ granules were observed near Golgi apparatus, and their contents were similar to the materials seen in Golgi apparatus. From morpholgical studies, it was concluded that these type Ⅱ granules matured to type I granules, and that they were transferred to the cell periphery and their contents were released by exocytosis

Multiple q-Mahler measures and zeta functions

AbstractWe introduce multiple q-Mahler measures and we calculate some specific examples, where multiple q-analogues of zeta functions appear. We study also limits as the multiple q goes to 1