Enhanced energy relaxation process of quantum memory coupled with a superconducting qubit

For quantum information processing, each physical system has different advantage for the implementation and so hybrid systems to benefit from several systems would be able to provide a promising approach. One of the common hybrid approach is to combine a superconducting qubit as a controllable qubit and the other quantum system with a long coherence time as a memory qubit. The superconducting qubit allows us to have an excellent controllability of the quantum states and the memory qubit is capable of storing the information for a long time. By tuning the energy splitting between the superconducting qubit and the memory qubit, it is believed that one can realize a selective coupling between them. However, we have shown that this approach has a fundamental drawback concerning energy leakage from the memory qubit. The detuned superconducting qubit is usually affected by severe decoherence, and this causes an incoherent energy relaxation from the memory qubit to the superconducting qubit via the imperfect decoupling. We have also found that this energy transport can be interpreted as an appearance of anti quantum Zeno effect induced by the fluctuation in the superconducting qubit. We also discuss a possible solution to avoid such energy relaxation process, which is feasible with existing technology

Inverse columnar-equiaxed transition (CET) in 304 and 316l stainless steels melt by electron beam for additive manufacturing (AM)

According to Hunt’s columnar-to-equiaxed transition (CET) criterion, which is generally accepted, a high-temperature gradient (G) in the solidification front is preferable to a low G for forming columnar grains. Here, we report the opposite tendency found in the solidification microstructure of stainless steels partially melted by scanning electron beam for powder bed fusion (PBF)-type additive manufacturing. Equiaxed grains were observed more frequently in the region of high G rather than in the region of low G, contrary to the trend of the CET criterion. Computational thermal-fluid dynamics (CtFD) simulation has revealed that the fluid velocity is significantly higher in the case of smaller melt regions. The G on the solidification front of a small melt pool tends to be high, but at the same, the temperature gradient along the melt pool surface also tends to be high. The high melt surface temperature gradient can enhance Marangoni flow, which can apparently reverse the trend of equiaxed grain formation.Miyata Y., Okugawa M., Koizumi Y., et al. Inverse columnar-equiaxed transition (CET) in 304 and 316l stainless steels melt by electron beam for additive manufacturing (AM). Crystals 11, 856 (2021); https://doi.org/10.3390/cryst11080856

Modified cellular automaton simulation of metal additive manufacturing

Metal additive manufacturing (AM) technologies are attracting attentions not only as a fabrication process of complicated threedimensional parts but also as microstructure controlling processes. In powder bed fusion (PBF)-type AM, crystallographic texture can be controlled by scanning strategies of energy beam. To optimize microstructures, computer simulations for predicting microstructures play very important roles. In this work, we have developed simulation programs to explain the mechanism of the crystal orientation control. First, we simulated the shape of melt pool by analyzing the heat transfer using apparent heat conductivity when the penetration of laser beam through keyholes was taken into consideration because of the evaporation and accompanying convections. It was assumed that the primary crystal growth direction can be determined by the temperature gradient, and the crystals grow keeping the growth direction as generally recognized. The shapes of simulated melt pools agree well with experimental observations. The modified cellular automaton simulations successfully reproduced two typical textures with different preferential orientations along the building directions of (100) and (110) when the bidirectional scanning with and without a rotation of 90°, respectively, was accomplished between the layers.Kubo J., Koizumi Y., Ishimoto T., et al. Modified cellular automaton simulation of metal additive manufacturing. Materials Transactions 62, 864 (2021); https://doi.org/10.2320/matertrans.MT-M2021009

Equiaxed grain formation by intrinsic heterogeneous nucleation via rapid heating and cooling in additive manufacturing of aluminum-silicon hypoeutectic alloy

The high strength of Al-Si hypoeutectic alloys additively manufactured by powder-bed fusion is of great scientific interest. To date, the mechanism of grain refinement near the fusion line, which contradicts conventional Hunt's columnar–equiaxed transition criteria, remains to be elucidated. Here we present the first report on the mechanism of grain refinement. When a laser was irradiated on cast Al-Si alloy consisting of coarse α-Al grain and α-Al/Si eutectic regions, grain refinement occurred only near the eutectic regions. This strongly suggests that the Si phase is crucial for grain refinement. Multi-phase-field simulation revealed that rapid heating due to the laser irradiation results in unmelted Si particles even above the liquidus temperature and that the particles act as heterogeneous nucleation sites during the subsequent re-solidification. These results suggest the feasibility of a novel inoculant-free grain refinement that is applicable to eutectic alloys comprising phases with a significant melting point difference.Masayuki Okugawa, Yuta Ohigashi, Yuya Furishiro, Yuichiro Koizumi, Takayoshi Nakano, Equiaxed grain formation by intrinsic heterogeneous nucleation via rapid heating and cooling in additive manufacturing of aluminum-silicon hypoeutectic alloy, Journal of Alloys and Compounds, Volume 919, 2022, 165812, ISSN 0925-8388, https://doi.org/10.1016/j.jallcom.2022.165812

Grazing on Microcystis (Cyanophyceae) by testate amoebae with special reference to cyanobacterial abundance and physiological state

We examined the growth of testate amoebae preying on Microcystis whose physiological states were different in laboratory experiments and a hypertrophic pond. We prepared three experimental systems using water samples dominated by Microcystis aeruginosa: light incubation (control), dark incubation (dark), and light incubation with addition of nitrogen and phosphorus (+NP). In all the systems, the colony density of M. aeruginosa decreased slightly during incubation. Physiological activity of phytoplankton as determined by chlorophyll fluorescence was high and almost constant in the control and +NP systems, whereas it decreased in the dark system. Cell densities of testate amoebae increased in the control and +NP systems, whereas in the dark system they remained low. Thus, growth of the amoebae was low in the systems where physiological activity of Microcystis was low. In a hypertrophic pond, cell density of testate amoebae increased and remained high when M. aeruginosa predominated. Cell density of testate amoebae increased remarkably, simultaneously with the increases in M. aeruginosa colony density and phytoplankton physiological activity. We also found a significant correlation between densities of M. aeruginosa colonies and testate amoebae. We suggested that the physiological activity of Microcystis is one important factor affecting the growth of testate amoebae grazing on Microcystis

Fusion of Ni Plating on CP-Titanium by Electron Beam Single-Track Scanning: Toward a New Approach for Fabricating TiNi Self-Healing Shape Memory Coating

The limited wear resistance of commercially pure titanium (CP-Ti) hinders its use in abrasive and erosive environments, despite its good strength–weight ratio and corrosion resistance. This paper reports the first study proposing a novel method for wear-resistant TiNi coating through Ni plating and electron beam (EB) irradiation in an in situ synthetic approach. Single-track melting experiments were conducted using the EB to investigate the feasibility of forming a TiNi phase by fusing the Ni plate with the CP-Ti substrate. Varying beam powers were employed at a fixed scanning speed to determine the optimal conditions for TiNi phase formation. The concentration of the melt region was found to be approximate as estimated from the ratio of the Ni-plate thickness to the depth of the melt region, and the region with Ni-48.7 at.% Ti was successfully formed by EB irradiation. The study suggests that the mixing of Ti atoms and Ni atoms was facilitated by fluid flow induced by Marangoni and thermal convections. It is proposed that a more uniform TiNi layer can be achieved through multi-track melting under appropriate conditions. This research demonstrates the feasibility of utilizing EB additive manufacturing as a coating method and the potential for developing TiNi coatings with shape memory effects and pseudoelasticity.Wang L., Okugawa M., Konishi H., et al. Fusion of Ni Plating on CP-Titanium by Electron Beam Single-Track Scanning: Toward a New Approach for Fabricating TiNi Self-Healing Shape Memory Coating. Materials 16, 5449 (2023); https://doi.org/10.3390/ma16155449

Control of crystallographic texture and mechanical properties of hastelloy-X via laser powder bed fusion

The influence of various laser powder bed fusion (LPBF) process parameters on the crystallographic textures and mechanical properties of a typical Ni-based solid-solution strengthened alloy, Hastelloy-X, was examined. Samples were classified into four groups based on the type of crystallographic texture: single crystalline-like microstructure with //build direction (BD) (-SCM), single crystalline-like microstructure with //BD (-SCM), crystallographic lamellar microstructure (CLM), or polycrystalline microstructure (PCM). These four crystallographic textures were realized in Hastelloy-X for the first time here to the best of our knowledge. The mechanical properties of the samples varied depending on their texture. The tensile properties were affected not only by the Schmid factor but also by the grain size and the presence of lamellar boundaries (grain boundaries). The lamellar boundaries at the interface between the //BD oriented main layers and the //BD-oriented sub-layers of CLM contributed to the resistance to slip transmission and the increased proof stress. It was possible to control a wide range of crystallographic microstructures via the LPBF process parameters, which determines the melt pool morphology and solidification behavior.Hibino S., Todo T., Ishimoto T., et al. Control of crystallographic texture and mechanical properties of hastelloy-X via laser powder bed fusion. Crystals, 11, 9, 1064. https://doi.org/10.3390/cryst11091064

Root canal treatment with high-frequency waves in rats

The purpose of this study was to develop a high-frequency wave therapy model in rats and to investigate the influence of high-frequency waves on root canal treatment, which may provide a novel strategy for treating apical periodontitis. Root canal treatments with and without high-frequency wave irradiation were performed on the mandibular first molars of 10-week-old male Wistar rats. The mesial roots were evaluated radiologically, bacteriologically, and immunohistochemically. At 3 weeks after root canal treatment, lesion volume had decreased significantly more in the irradiated group than in the non-irradiated group, indicating successful development of the high-frequency therapy model. The use of high-frequency waves provided no additional bactericidal effect after root canal treatment. However, high-frequency wave irradiation was found to promote healing of periapical lesions on the host side through increased expression of fibroblast growth factor 2 and transforming growth factor-β1 and could therefore be useful as an adjuvant nonsurgical treatment for apical periodontitis

RBM10 in complete hydatidiform mole: cytoplasmic occurrence of its 50 kDa polypeptide

Background: RNA-binding motif protein 10 (RBM10), originally identified as S1-1 protein, is a nuclear protein with likely functions in transcription and RNA splicing. The RBM10 gene maps to the X chromosome and, in female cells, is inactivated in one of the two X chromosomes near the boundary with genes escaping inactivation. This study investigated the occurrence of the RBM10 gene product in complete hydatidiform mole, which is composed of cells with paternal diploid chromosomes (46, XX).Methods: Deparaffinized normal chorion or complete hydatidiform mole tissues were hybridized with a fluorescein-conjugated RBM10 gene probe in fluorescent in situ hybridization (FISH) analysis. Immunohistochemistry and immunoelectron microscopy of the tissues were performed using an anti-RBM10 antiserum. Proteins from complete hydatidiform mole tissues and those separated by anti-RBM10-linked affinity chromatography were also examined by western blotting.Results: As expected, the RBM10 gene was detected by FISH as double spots in the nuclei of complete hydatidiform mole cells. Immunohistochemistry revealed a nuclear presence of RBM10 in normal chorion and complete hydatidiform moles, and a notable cytoplasmic presence in complete hydatidiform moles. Western blotting and immunoaffinity chromatography revealed that a 50 kDa protein was predominantly found in the cytosolic fraction of complete hydatidiform moles.Conclusions: A 50 kDa protein with common antigenicity to RBM10 was found in the cytoplasm of complete hydatidiform mole cells, and could represent one of the characteristics of the disease

Assessment of the functional efficacy of root canal treatment with high-frequency waves in rats

The purpose of this study was to develop a high-frequency wave therapy model in rats and to investigate the influence of high-frequency waves on root canal treatment, which may provide a novel strategy for treating apical periodontitis. Root canal treatments with and without high-frequency wave irradiation were performed on the mandibular first molars of 10-week-old male Wistar rats. The mesial roots were evaluated radiologically, bacteriologically, and immunohistochemically. At 3 weeks after root canal treatment, lesion volume had decreased significantly more in the irradiated group than in the non-irradiated group, indicating successful development of the high-frequency therapy model. The use of high-frequency waves provided no additional bactericidal effect after root canal treatment. However, high-frequency wave irradiation was found to promote healing of periapical lesions on the host side through increased expression of fibroblast growth factor 2 and transforming growth factor-β1 and could therefore be useful as an adjuvant nonsurgical treatment for apical periodontitis.Assessment of the functional efficacy of root canal treatment with high-frequency waves in rats. Saori Matsui, et al. PLOS ONE. 2020.9(29) doi.org/10.1371/journal.pone.023966