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In order to investigate the distinguishability about the progenitors of FeCCSNe and ECSNe, we calculate the luminosities and spectra of their pre-SN neutrinos and estimate the number of events at neutrino detectors.
This study investigated a new effective method for controlling the capsalid monogenean Neobenedenia girellae. We examined in vitro and in vivo the effect on the percentage survival of N. girellae in buffers containing different metallic ions. Decreased survival was observed in buffer solutions lacking two ions. In particular, the percentage survival of N. girellae was significantly decreased after 10 min exposure to buffer containing neither Ca2+ nor Mg2+. Transmission electron microscopic observations showed that treatment with this buffer disrupted intercellular junctions. This significant effect on percentage survival of N. girellae using Ca2+/Mg2+-free buffer was confirmed in an in vivo assay. Ca2+/Mg2+-free buffer had no effect on the condition of the host, spotted halibut Verasper variegates (Pleuronectidae). These results suggest that treatment with Ca2+/Mg2+-free buffer is a new effective control method, which could replace existing control methods.
Stars more massive than ~ 20 − 25 M⊙ form a black hole at the end of their evolution. Stars with non-rotating black holes are likely to collapse “quietly” ejecting a small amount of heavy elements (faint supernovae). In contrast, stars with rotating black holes are likely to give rise to very energetic supernovae (hypernovae). We present distinct nucleosynthesis features of these two types of “black-hole-forming” supernovae. Nucleosynthesis in hypernovae is characterized by larger abundance ratios (Zn, Co, V, Ti)/Fe and smaller (Mn, Cr)/Fe than normal supernovae, which can explain the observed trend of these ratios in extremely metal-poor stars. Nucleosynthesis in faint supernovae is characterized by a large amount of fall-back. We show that the abundance pattern of the recently discovered most Fe-poor star, HE0107-5240, and other extremely metal-poor carbon-rich stars are in good accord with those of black-hole-forming supernovae, but not pair-instability supernovae. This suggests that black-hole-forming supernovae made important contributions to the early Galactic (and cosmic) chemical evolution. Finally we discuss the nature of first (Pop III) Stars.
Process-induced defects are a serious issue for modern sub-micron
Si LSIs. To characterize such defects, two different techniques
are useful: electrically detected magnetic resonance (EDMR) and
transmission electron microscope (TEM), which can detect small
(point) and extended defects, respectively. We applied EDMR and
TEM to the issue of defect-induced leakage currents in
dynamic-random-access memory (DRAM) cells. For our DRAM samples
(a 0.25-μm-rule series), although TEM showed no extended defects,
EDMR successfully detected two types of point defects:
V2+Ox (Si divacancy-oxygen complexes) and larger Si vacancies
(at least larger than V6). We confirmed that these defects are the
source of DRAM leakage currents. The observed defects were formed by ion
implantation processes, but were more thermally stable than those in bulk
Si crystals. The origins of this enhanced stability are attributed to the
presence of oxygen atoms and a strong mechanical strain in LSIs. To clarify
the origin of the complicated strain in LSI structures, we can directly
measure the local-strain distribution in DRAM samples by means of
convergent-beam electron diffraction (CBED) using TEM, which provides us
with a valuable hint for understanding the formation mechanism of
Non-steady-state solidification of YBa2Cu3O6+δ (Y-123) superconducting oxides was observed by the isothermal undercooling experiment. A sudden decrease in crystal growth rate was found for all the Y-123 samples processed at the different temperatures and from the different Y2BaCuO5 (Y-211) contents in the initial composition. Quantitative analysis revealed that the Y-211 particles are pushed by the Y-123 crystal and accumulate in the liquid during solidification. It is also found that the particle volume fraction increased and reached a constant value of about 0.6, when the growth rate decreased abruptly, regardless of a variety of growth conditions. A simple solidification model is developed to interpret the experimental observation. This model shows that particle accumulation, as a result of the particle-pushing behavior, causes less connectivity of the liquid and thereby decreases the liquid diffusion flux, which is responsible for the non-steady-state solidification of Y-123.
Microstructure control of SmBCO superconductor was carried out using the floating zone partial melting and solidification method under 0.01 atm oxygen partial pressure which is a preferable atmosphere to obtain a crystal with stoichiometric SmBCO. The growth rate, initial composition, and addition of small amount of platinum dependences on the microstructure formations of the (Sm211 + L) mixture during melting and the Sm123 or Sm123/211 during solidification were investigated. Furthermore, superconductive properties of the solidified Sm123/211 were measured by SQUID after appropriate oxygen annealing. Estimated critical current density of the single crystalline Sm123/211 was 3.6 × 104 A/cm at 77 K, 1 T.
Microstructure in melt-textured bulk RE1Ba2Cu3O6+d crystals (RE123; RE = Sm, Nd) was investigated, changing the initial composition from the tie-line composition of RE123–Sm2Ba1Cu1O5 (Sm211)/Nd4Ba2Cu2O10 (Nd422) to the Ba-enriched side. It was found that the Sm211/Nd422 particle size decreased in the liquid with increasing the Ba/Cu ratio of the initial composition, and this tendency was also found in the grown Sm123 crystals. Composition of the Sm123 grown crystal could be controlled by selecting the Ba-enriched initial composition to obtain an almost stoichiometric compound, which resulted in higher Tc values. Furthermore, the Jc values also increased under low magnetic fields due to the significant decrease of Sm211 particle size. Therefore, changing the initial composition toward the Ba-enriched side was found to be a new process to enhance both Jc and Tc values simultaneously.
Nd1+xBa2−xCu3O6+d (Nd123) single crystals have been successfully grown by the top-seeded solution-growth method. Compositions of Nd123 could be controlled by applying two different methods: control of the oxygen partial pressure of the atmosphere and control of the liquid composition in air. The critical temperatures of Nd123 obtained by these two methods were 96 K (oxygen control) and 95 K (liquid composition control), respectively. The relationship between the peak effect in the Jc-H curve and heat treatment was investigated. The peak effect was found not to be an intrinsic property of Nd123; consequently it could be controlled by heat treatment.
Microstructure control of the SmBCO superconductor was carried out using the floating zone partial melting and solidification method. It is generally recognized that finely and uniformly dispersed nonsuperconductive high temperature stable phase (Sm211) particles included in the superconductive Sm123 matrix act as effective pinning centers. Microstructure formation of the partial molten mixture (Sm211 particles and BaO–CuO liquid) by decomposition of the precursor Sm123 on melting and solidification of Sm123 from the mixture have to be controlled concurrently to fabricate the 123/211 composite fiber with the optimum microstructure. During unidirectional solidification, planar crystal growth which provides the single crystal growth of Sm123 becomes unstable with increased growth rate. During unidirectional melting, the mean diameter of aligned Sm211 particles behind the melting interface decreases with increased growth rate and with decreased temperature gradient at the melting interface. Initial composition of the precursor significantly affects the formation behavior of Sm211 particles. The contribution of process parameters to the microstructure formation is also briefly discussed.
Nanoparticles of Cu were fabricated by negative-ion implantation, leading to spontaneous formation at high beam fluxes. Negative ions, alleviating surface charging, exhibit significant merits in carrying out low-energy implantation at high dose rates. The kinetic processes were studied by measuring dose-rate dependence of colloid formation and resultant optical properties. Negative-Cu ions of 60 keV were implanted into silica glasses at high-current densities, up to 260 μA/cm2, fixing the total dose at 3.0 × 1016 ions/cm2. Spherical nanocrystals of Cu atoms formed within a narrow region, near the projectile range of Cu ions. Simultaneously, much smaller particles spread out beyond a depleted zone, deeper than the projectile range. The nanocrystal growth and optical properties were greatly dependent on the dose rate and the specimen boundary condition. The growth process is explained by a droplet-model based on surface tension and radiation-induced diffusion. Beam-surface interactions also play an important role in the mass transport from the beam flux to the interior solid.
A simple model is proposed to analyze the interface stability of the RE123 superconductor in accordance with the constitutional supercooling criterion. As the single crystal growth of the 123 phase is largely dependent on the growth interface stability, a quantitative analysis has been required. From the numerical analysis for the case of peritectically solidified Sm123, it was clarified that the constitutional supercooling must exist in the liquid when the 123 growth interface comes close to a 211 particle. It could also predict that larger 211 particle radius, smaller volume fraction of the 211 particles, larger growth rate, or smaller imposed temperature gradient cause easy occurrence of the constitutional supercooling. The growth rate and a 211 particle radius are determining parameters. Further consideration of the nucleation at the L/211 interface just ahead of the 123 growth front could describe the 123 growth morphological transition from with the planar interface to the equiaxed blocky.
In-situ electron-spin-resonance (ESR) measurements of film growth of hydrogenated amorphous silicon (a-Si:H) using a remote hydrogen plasma technique have been performed. The Si dangling-bond signal in a-Si:H during and after deposition has been detected, in addition to the gas-phase ESR signals both of atomic hydrogen and photo-excited SiHx molecules. Dynamic changes of the Si dangling-bond signal intensity were observed when the deposition started and stopped, which has suggested the existence of a subsurface region with higher spin density than that in the bulk region.
Hydrogenated amorphous silicon (a-Si:H) samples containing 17O (3 x 1019 cm-3, nuclear spin, I, = 5/2) and 13C (3 - 4 x 1017cm-3, I = 1/2) isotope impurities were used in the detailed pulsed electron spin resonance (ESR) and pulsed electron-nuclear double resonance (ENDOR) measurements to obtain information on the role of O and C impurities in lightinduced metastable dangling bonds in a-Si:H. No hyperfine structure related to 17O and 13C atoms was observed in echo detected ESR, electron spin echo envelope modulation (ESEEM) of pulsed ESR as well as pulsed ENDOR (Davies and Mims sequences), which suggests that O and C impurities are not directly involved in the formation of light-induced dangling bonds.
A rare case of pharyngeal cyst arising from the second branchial cleft in a 14-year-old boy is described. A cyst located in the right posterolateral wall of the oropharynx was completely removed by an intraoral approach. Histopathological examination revealed that the cyst was lined with columnar (respiratory type) epithelium.
Three cases of inter-sterno-costo-clavicular ossification (ISCCO) associated with chronic tonsillitis are reported. Two cases had additional symptoms of pustulosis palmaris et plantaris (PPP). All the patients underwent tonsillectomy. The histological changes of the palatine tonsils of case 1 and case 2 were characterized by so-called focal small lacunar ulcers and periarteriolar fibrosis (onion-skin lesion). Some multinucleated giant cells were observed in case 2. Following tonsillectomy, symptoms in the clavicular region and the PPP improved. It is possible to consider that ISCCO is caused by focal tonsillar infection.
Total or segmental agenesis of the internal carotid artery is a rare anomaly. The cervical portion of the internal carotid artery was absent in the right side of the patient who was carried out radical surgery due to recurrent oropharyngeal cancer. Post-operative venous digital subtraction angiography revealed that the remaining intracranial portion of the internal carotid artery was normally patent and supplied blood flow via ipsilateral external carotid artery. Otolaryngologist-Head and Neck surgeon should know such a vascular anomaly and avoid a disastrous result on dividing external carotid artery.
An extremely rare case of intravagal parathyroid adenoma is presented. The tumour caused fusiform swelling of the left vagus nerve was shelled out. Post-operatively the left recurrent nerve palsy was recovered in the two months. Serum calcium level returned to normal on the tenth day after the surgical operation without symptoms of hypocalcaemia.
Superconducting YBa2Cu3O7-δ, ceramic pieces and fibers were prepared through a sol-gel route from ametal acetate aqueous solution of controlled pH. Concentrating the starting solution by evaporating the solvent provided a transparent viscous sol, from which gel fibers could be drawn. Further concentrating of the viscous solution led to formation of gel pieces. Conversion of gel fibers and pieces to superconductors were investigated in terms of precipitating crystalline species and electrical conductivities.