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Magnetic bearings composed of multiple basic cubic superconducting bulks were investigated. This paper aimed to integrate multiple basic cubic bulks with different performance characteristics and to control the magnetic field properties through design of their arrangement. If this magnetic field characteristic can be controlled, then the optimum configuration for a magnetic bearing can be deduced. In this paper, we aimed to control magnetic bearings with a plurality of basic unit cubic bulks and to control variations in the magnetic characteristics of the bearing surfaces via the arrangement design. We performed calculations of the optimum arrangement that minimizes the inclination angle of the rotation axis of the floating rotating body by combining the structural arrangement pattern of the bearing surface. We constructed a model with a three-row, three-column square arrangement and calculated the layout pattern via an optimization calculation. The cubic bulk was then constructed with this arrangement pattern, and the inclination of the axis of rotation of the floating body was measured using a laser sensor and compared with the calculation result. In addition, the distance between the bearing surface and floating body and the levitation force were measured. We confirmed that suppressing the inclination of the rotation angle through the optimum arrangement was highly effective, indicating the feasibility of controlling the levitation force.

To realize a superelastic Mg-Sc lightweight alloy at room temperature, we investigated the stress–strain behavior of Mg-18.7 at.% Sc alloy sheets at room temperature with martensitic transformation starting temperature of approximately −90 °C. We found that the superelasticity of the alloy strongly depends on the grain size and a distinct room temperature superelasticity (~3% superelastic strain) was obtained in the alloy with a large grain size. The obtained maximum superelastic strain was smaller than that expected from the orientation dependence of the transformation strain. This result suggests that the stress-induced martensite phase was stabilized because of the introduction of slip defects.

Hornets belong to the genus of Vespa, and are potentially effective predators of insect pests in forests and other environments. To assess the potential impact of prey foraging by the Vespa species, studies have attempted to understand species composition of hornets caught with bait traps in several regions in Japan. These studies showed that the species composition of hornets was different among the different regions in Japan, possibly due to the differences in the geographical distribution and climates. Additionally, the species composition of hornets has only been examined in the inland regions of Japan. In this study, we studied species composition of hornets caught with bait traps in Niigata city on the coast of the Sea of Japan, for a period of four years. The species composition observed in Niigata city was very similar to the composition seen in other temperate, warmer regions, but diffe¬rent from that in subarctic and heavy snowfall regions. There was a single peak in the trap catch due to seasonal changes in the two major species, V. analis and V. ducalis. There were also yearly changes in the species composition of hornets in Niigata city. The possible causes of the differences among the hornet populations in the seasons and years are discussed in this study.

The objective of this study is to clarify the effects of web position on the shear resistance mechanism of Ultra High Strength Fiber Reinforced Concrete (UFC) beams. Four-point bending tests were conducted on total three beams with different web positions, i.e. centered web, two webs arranged at the quarter of the flange and two webs at the edge of the flange. The results revealed the structural performances such as shear capacity, flexural rigidity, displacement at the shear failure and post peak behavior differed in each specimen. The different structural performances can be explained by the difference in the area resisting the shear force, which is determined by the existence of flange overhang and whether webs were distributed in the flange.

Summary Background & aims The associations between dietary magnesium intake and stroke and coronary heart disease (CHD) incidences are inconsistent and not established in Asian. We aimed to determine the association between dietary magnesium intake and the risk of stroke and CHD in a Japanese population. Subjects/Methods We studied 85,293 Japanese subjects by questionnaire at baseline (age 45–74 years, without cardiovascular disease or cancer in 1995 and 1998 for Cohorts I and II, respectively). The participants were followed until the end of 2009 and 2010 in Cohorts I and II, respectively. Dietary magnesium intake was estimated from a self-administered 138-item food-frequency questionnaire. Results After 1,305,738 person-years of follow-up, 4110 strokes and 1283 cases of CHD were documented. The multivariable-adjusted hazard ratios (HRs, 95% confidence intervals, 95%CIs) of CHD for the fourth and fifth quintiles of dietary magnesium intake were 0.70 (0.50–0.99) and 0.66 (0.44–0.97) in men (P for trend = 0.036), respectively, and third quintile of dietary magnesium intake was 0.61 (0.39–0.96) in women (P for trend = 0.241), compared with the lowest quintile in men and women. We observed no decreased risks of incident stroke in men or women with higher dietary magnesium intakes. Conclusions Higher dietary magnesium intake was associated with a reduced risk of CHD in Japanese men.

This paper describes the first persistent-mode medium magnetic field (400 MHz; 9.39 T) nuclear magnetic resonance (NMR) magnet which uses superconducting joints between high-temperature superconductors (HTSs). As the ultimate goal, we aim to develop a high-resolution 1.3 GHz (30.5 T) NMR magnet operated in the persistent-mode. The magnet requires superconducting joints between HTSs and those between an HTS and a low-temperature superconductor (LTS). Towards this goal, we have been developing persistent-mode HTS inner coils to be operated in a 400 MHz (9.39 T) NMR magnet and here we present the first prototype inner coil wound with a single piece (RE = rare earth)Ba2Cu3O7−x (REBCO) conductor. The coil and a REBCO persistent current switch are connected with intermediate grown superconducting joints with high critical currents in external magnetic fields. To evaluate the performance of the joints in an ultimately stable and homogeneous magnetic field, the coil is operated in the persistent-mode, generating 0.1 T, in a 9.3 T background magnetic field of a persistent-mode LTS outer coil. The magnetic field drift over two years of the 400 MHz LTS/REBCO NMR magnet is as small as ∼1 ppm, giving high-resolution NMR spectra. The magnetic field drift rate over the second year was 0.03 × 10−3 ppm h−1, which is more than three orders of magnitude smaller than that required for an NMR magnet, demonstrating that the superconducting joints function satisfactorily in a high-resolution NMR system. The corresponding joint resistance is inferred to be −14 Ω.

Aims Coping strategies may be significantly associated with health outcomes. This is the first study to investigate the association between baseline coping strategies and cardiovascular disease (CVD) incidence and mortality in a general population cohort. Methods and results The Japan Public Health Center-based prospective Study asked questions on coping in its third follow-up survey (2000–04). Analyses on CVD incidence and mortality included 57 017 subjects aged 50–79 without a history of CVD and who provided complete answers on approach- and avoidance-oriented coping behaviours and strategies. Cox regression models, adjusted for confounders, were used to determine hazard ratios (HRs) according to coping style. Mean follow-up time was 7.9 years for incidence and 8.0 years for mortality. The premorbid use of an approach-oriented coping strategy was inversely associated with incidence of stroke (HR = 0.85; 95% CI, 0.73–1.00) and CVD mortality (HR = 0.74; 95% CI, 0.55–0.99). Stroke subtype analyses revealed an inverse association between the approach-oriented coping strategy and incidence of ischaemic stroke (HR = 0.79; 95% CI, 0.64–0.98) and a positive association between the combined coping strategy and incidence of intra-parenchymal haemorrhage (HR = 2.03; 95% CI, 1.01–4.10). Utilizing an avoidance coping strategy was associated with increased mortality from ischaemic heart disease (IHD) only in hypertensive individuals (HR = 3.46; 95% CI, 1.07–11.18). The coping behaviours fantasizing and positive reappraisal were associated with increased risk of CVD incidence (HR = 1.24; 95% CI, 1.03–1.50) and reduced risk of IHD mortality (HR = 0.63; 95% CI, 0.40–0.99), respectively. Conclusion An approach-oriented coping strategy, i.e. proactively dealing with sources of stress, may be associated with significantly reduced stroke incidence and CVD mortality in a Japanese population-based cohort.

For magnetic bearings combining multiple cubic superconducting bulks, placement is a crucial factor. In this paper, the magnetic bearing surface constructed by arrangement optimization was composed of eight superconducting cubic bulk units. The combined arrangement of cubic superconducting bulks was determined by optimizing the spatial uniformity of the magnetic bearing's trapped magnetic flux distribution. We constructed a physical model in which a permanent magnet in the form of a floating rotor was sandwiched from above and below by an integrated magnetic bearing surface. Using rotation test equipment and an encoder, we investigated the influence of an optimal arrangement index on rotation loss that occurs due to magnetic flux distribution nonuniformity. In addition, the rotation axis tilt angle due to nonuniform magnetic flux distribution was measured using a laser displacement meter. The advantage of the method proposed in this research is that the magnetic distribution can be controlled optimally depending on the arrangement of the cubic bulk when it is incorporated in various bulk applications, not limited to SMB.

In this paper, we constructed test equipment for a rotating machine that uses a superconducting bulk rotor and performed a rotation test. When a superconducting bulk rotor is used, a fluctuating magnetic field generates ac loss, it is possible to decrease its trapped magnetic flux. Performance of the rotating machine under test was influenced by the ac loss generated by a fluctuating ac magnetic field. We modeled the motor used in this paper on an axial-type synchronous motor, where the magnetic field generated by the stator coils causes the rotor to rotate. We then measured the influence of the stator coils on the superconducting bulk rotor. First, we confirmed that the temperature of the bulk rotor modules was properly controlled and could generate a trapped magnetic flux equal to that during zero-field-cooled magnetization. A technique for magnetizing two or more bulks concurrently was used. Next, we performed the rotation test at low speed. The maximum rotational speed during the test was 300 r/min. The operation time at a steady-state speed was 600 s. The maximum value of the generated magnetic field of the stator coils was 50 mT. Finally, we confirmed that a shielding ring made of superconducting wire decreased the influence of a fluctuating magnetic field.

In humans, periostin plays a critical role in the enhancement and chronicity of allergic skin inflammation; however, whether it is involved in the pathogenesis of canine dermatitis remains unknown. The aim of this study was to examine the expression patterns of periostin in healthy, atopic, and nonatopic chronically inflamed canine skin. Biopsy specimens from 47 dogs with skin disease and normal skin tissue from 5 adult beagles were examined by light microscopy, immunohistochemistry, and in situ hybridization. In normal skin, periostin was localized just beneath the epidermis and around the hair follicles. In chronically inflamed skin, periostin expression was most intense in the dermis with inflammatory cell infiltrates. In contrast, low levels of periostin were detected in acutely inflamed and noninflamed skin. Conversely, all canine atopic dermatitis tissues characteristically showed the most intense expression of periostin in the superficial dermis, particularly at the epidermal–dermal junction. In situ hybridization showed that periostin mRNA was broadly expressed in the basal epidermal keratinocytes, outer root sheath cells, and dermal fibroblasts in normal dog skin. High expression of periostin mRNA was observed in fibroblasts in dog skin with chronically inflamed dermatitis. Moreover, in some chronically inflamed skin specimens, periostin mRNA expression was increased in basal keratinocytes. The severity score of chronic pathologic changes and CD3+ cell number in the dermis were correlated with distribution pattern of periostin in the atopic skin. These data suggest that periostin could play a role in the pathophysiology of chronic dermatitis, including atopic dermatitis, in dogs.

Background and aims Higher intake of fish or n-3 polyunsaturated fatty acids (PUFAs) has been associated with reduced risk of coronary heart disease (CHD). However, it is unclear whether increased blood levels of n-3 PUFAs are associated with reduced risk of CHD in the Japanese population. Methods The relationship between circulating levels of n-3 PUFAs (eicosapentaenoic acid + docosapentaenoic acid + docosahexaenoic acid) and risk of CHD was examined in a nested case-control study among participants in the Japan Public Health Center (JPHC)-based Study Cohort. Plasma n-3 PUFA phospholipid levels were measured at baseline by gas chromatography in 209 cases with CHD and 418 controls matched for sex, age, date of blood draw, time elapsed since last meal before blood collection, and study location. The CHD cases (n = 209) comprised 168 cases of myocardial infarction and 41 of sudden cardiac death, otherwise classified as 157 non-fatal and 52 fatal coronary events, respectively. Mean duration of follow-up was 13.5 years. Results Multivariate conditional logistic analysis showed no significant association between n-3 PUFAs and risk of total CHD. The odds ratio (OR) for the highest versus lowest quartiles of plasma n-3 PUFAs was 0.79 (95% confidence interval [95% CI]: 0.41–1.51, p for trend = 0.51). Subtype analysis of CHD revealed that the multivariate ORs for the highest versus lowest quartiles for n-3 PUFAs were 0.91 (95% CI: 0.43–1.89, p for trend = 0.90) for myocardial infarction, 0.08 (95% CI: 0.01–0.88, p for trend = 0.04) for sudden cardiac death, 0.89 (95% CI: 0.42–1.89, p for trend = 0.97) for nonfatal coronary events, and 0.12 (95% CI: 0.02–0.75, p for trend = 0.03) for fatal coronary events. Conclusions Plasma n-3 PUFA levels were not associated with risk of total CHD but were inversely associated with risks of sudden cardiac death and fatal coronary events among middle-aged Japanese individuals.

Seafood/fish intake has been regarded as a protective factor for coronary heart disease (CHD), while smoking is a strong risk factor. To examine whether associations between smoking and risk of CHD are modified by seafood/fish intake, we studied 72,012 Japanese men and women aged 45-74 years who completed 2 food frequency questionnaires, 5 years apart, during the period 1995-2009. After 878,163 person-years of follow-up, 584 incident cases of CHD (101 fatal and 483 nonfatal), including 516 myocardial infarctions, were documented. There was a clear dose-response association between smoking and CHD risk among subjects with a low seafood/fish intake (

Trapped magnetic fluxes in HTS bulks are decayed when the bulks are subjected to perturbation of external magnetic fields. In HTS bulk apparatuses such as HTS bulk motors and magnetic levitation bearings, there is a possibility that the trapped magnetic fluxes in the bulks disappear because the bulks are inevitably subjected to perturbations of the external magnetic fields. For those apparatuses to work stably and reliably, it is necessary to develop methods to suppress the decay. It was shown in our previous experiments that the decay is caused by temperature rises of the bulks due to AC losses in the bulks. The authors proposed a method to put a shorted shielding coil wound of HTS wire around the bulk aiming at reduction of the AC losses in the bulk. It was experimentally shown by use of a shielding coil wound of Bi/Ag sheathed wire that the decay of the trapped magnetic flux was effectively suppressed. In this paper, shielding performance of the coil wound of GdBCO wire was experimentally investigated comparing with that of the coil wound of Bi/Ag sheathed wire. AC losses in the bulks and shielding coils are calculated for various arrangements of the shielding coil to find a preferable shielding coil arrangement from stand points of shielding performance and reduction of AC losses.

We studied the levitation properties for precious metals utilizing magneto-Archimedes effect under a high magnetic field gradient. In order to enhance the power factor of BdB/dz for the magnetic force in vertical direction cylindrical ferromagnetic materials were set into the room temperature bore of a 10 T superconducting solenoidal magnet. The maximum BdB/dz achieved the high value of −1598 T2/m by the optimum configuration of ferromagnetic materials. The magnetic levitation properties for several kinds of precious metals such as silver, gold and platinum in manganese chloride aqueous solution as a paramagnetic liquid medium were studied. The experimental results showed that silver, gold and platinum levitated at each different height which was almost the same as its own theoretical one and could be controlled by changing configuration of ferromagnetic materials. This indicates the strong possibility of the selective separation of a target material from the solid mixture by utilizing magneto-Archimedes levitation under a high magnetic field gradient.

Trapped magnetic fields in high temperature superconductor (HTS) bulks are decayed when the bulks are subjected to perturbation of magnetic fields. This phenomenon is inconvenient for the applications of HTS bulks and it is necessary to develop methods to suppress the decay. It was found in a previous study that the decay is caused by temperature rises of the bulks due to AC losses in the bulks. Therefore, it is necessary to develop a method to reduce the AC losses. In this work, a method is proposed to reduce the AC losses by putting HTS shield rings around the bulk and shielding performance of the rings were investigated. The experimental result shows that the shielding rings can drastically suppress the decay, even if the bulk is used in the same cooling condition and the effectiveness of the method was demonstrated.

Objectives: Previous studies have suggested that living in a multi-generational household (a type of family structure prevalent in Japan) confers mixed health benefits and stresses, especially for women who report such living arrangements. In this prospective cohort study, we sought to examine the impact of living arrangements on coronary heart disease incidence and mortality as well as all-cause mortality in a large prospective cohort of Japanese population. Methods: We examined prospectively the association between living arrangement and risk of coronary heart disease incidence and mortality within a cohort of 90,987 Japanese women and men aged 40-69 years, free of prior diagnosis of cancer and cardiovascular disease. A total of 671 cases of newly diagnosed coronary heart disease, 339 coronary heart disease deaths, and 6,255 all-cause deaths occurred between the baseline questionnaire (1990-1994) and the end of follow-up in January 2004. Results: After adjustment of potentially confounding variables, women living in multi-generational households (living with spouse-children-parents; or spouse-parents) had 2.0 to 3.0-fold higher risk of coronary heart disease compared to women living with spouses only. Women living with spouses and children also had 2.1-fold higher risk of coronary heart disease incidence compared to married women living without children. Conclusions: Women in a multi-generational family had a higher risk of coronary heart disease incidence, probably due to stress from multiple family roles.

We investigated uni-axial tensile stress dependence of AC losses (transport current, magnetization and total losses) in HTS coated conductor with magnetic Ni-alloy substrate. The AC loss characteristics are studied by relating to tensile stress dependence of critical currents of the conductor. Experimental results showed that the loss characteristics were different whether the critical current recovered the original value after the release of the stress or not. Dependence of AC loss characteristics on magnetic property of the substrate is also studied.

application/pdf, The hydrogen internal friction peak in Zr50-metallic glasses (Zr50Cu50, Zr50Cu40Al10 and Zr50Cu35Al10Ni5) was studied. The hydrogen internal friction peak was shifted exponentially to lower temperatures with increasing hydrogen concentration similarly to other Zr-Cu base metallic glasses reported in the literature. The peak height increased in proportion to the square-root of hydrogen concentration. These results were discussed in the view point of the hydrogen induced structural relaxation in these metallic glasses.

application/pdf, In order to clarify the hydrogen-induced structural relaxation (HISR) of hydrogenated bulk and marginal metallic glasses (BMG and MMG), the hydrogen concentration (CH) dependence of the peak temperature (Tp) and the peak height (View the MathML source) of the hydrogen internal friction peak (HIFP) in a-Zr55Cu30Al10Ni5 (numbers indicate at.%) (BMG), a-Zr54Cu30Al10Ni5Si1 (MMG) and a-Zr40Cu49Al10Si1 (MMG) were studied. It is found that the Tp versus CH data and the View the MathML source versus CH data are well explained by the relationships of Tp = ΔTp exp(−CH/τH) + Tp,0 and View the MathML source, respectively, not only for all the present metallic glasses but also for various Zr-base BMG and MMG reported. The characteristic CH dependence of Tp and View the MathML source was attributed to effects of the HISR. The detailed features of the CH dependence of Tp and View the MathML source were discussed in the light of material parameters and HISR.

HTS bulk can trap higher magnetic field than a permanent magnet, and non-contact magnetic bearings, electric motors and magnetic levitations are promising applications. The HTS bulks in those electric machines are exposed to magnetic field perturbations, which cause AC losses in the bulks. The AC losses deteriorate not only the efficiency of the apparatuses but also the performance by decaying trapped magnetic field. Therefore, it is important to understand the AC loss characteristics. We developed an electric method to measure the AC losses in a bulk using a double pick-up coil method. In this paper, correction factors are formulated to improve the accuracy of the method and the validity of the method is investigated by comparing the data measured by the electric and calorimetric methods.

Hydrogenated Zr-Cu-base metallic glasses (MGs) are the potential high-damping and high-strength materials. On the other hand, the knowledge on the material parameters which govern the peak temperature, Tp, and the peak height, Q-1 p, of the hydrogen internal friction peak (HIFP) remains poor. In order to pursue this issue, the hydrogen concentration dependence of Tp and Q-1 p in the Zr-Cu-base MGs were investigated in the point of view of the hydrogen induced structural relaxation (HISR). It is found that the Tp vs. CH data and the Q-1 p vs. CH data are well fitted by the relationships of Tp = Tp exp(-CH/τH) +Tp,0 and Qp -1 ∝ ln(CH/τH), respectively, for various Zr-Cu-base MGs including bulk MGs, Zr55Cu30Al10Ni5 and Zr60Cu30Al10. That is, the observed relationship between Tp and CH is mainly governed by HISR. It is suggested that Tp,0 in Zr-Cu-base MGs is the highest among various MGs resulting in the highest Tp in Zr-Cu-base MGs. In other words, the control of Tp,0 is the key issue to find the high-Tp MGs.

Stress dependencies of AC transport current losses, magnetization losses and total losses were investigated applying tensile stresses to an YBCO (IBAD/PLD) conductor. Measured transport current losses showed slight stress dependence in the range of 0~1 GPa. That can be explained by stress dependence of the critical current of the conductor. The magnetization and total losses are less sensitive to the stress than the transport current losses

HTS bulk can trap higher magnetic field than a permanent magnet and electric motor and actuators are promising applications. The HTS bulks in those electric machines are exposed to AC magnetic field perturbations, which cause AC losses in the bulks. Therefore, it is important to understand the AC loss characteristics. In the previous works, we measured the AC losses by an electric method using the double pick-up coils method. This time, we measured the AC losses by a calorimetric method using a cryo-cooler and heater at different temperature. In this paper, the AC losses measured by the electric and calorimetric methods are compared with each other to investigate the validity of the measurement methods.

A novel stacked combline antenna was fabricated for driving plasma current in order to control the rotational transform profile in the Large Helical Device. The antenna has ten elements facilitating excitation of fast-wave traveling in the toroidal direction.Each antenna element has an electrical length of a half-wavelength and is supported at the midpoint from the back plate by a metallic block. Such an antenna has two modes: even and odd. A mixed excitation of these modes will reduce the current drive efficiency. The electrical properties of this antenna were studied in an attempt to find ways of exciting a traveling wave of pure even mode. A matching section was used in combination and proved to be a good measure to improve the directionality over that of a bare combline antenna. It is confirmed in this paper that the fabricated real antenna has fairly good even-mode purity keeping the odd-mode intensity at a tolerable level. An antenna with insulating supports instead of the metallic supports is also examined, and it is found that even-mode purity is further improved. For practical uses, an entire system including impedance matching and power circulation is proposed, and sensitivity to a change in plasma loading ismore » analyzed. Finally, the power-handling capability is discussed including estimations of plasma loading and driven current reaching an assertion of consistency with the experimental goal.« less

HTS bulks applied to electric machines are exposed to AC magnetic field perturbations which cause AC losses in the bulks. AC losses affect the efficiency of the machines and decay the trapped magnetic field in an HTS bulk. Critical current density and the maximum trapped magnetic field of a bulk are enhanced as temperature is decreased. Thereby, the lower temperature operation of the bulk is preferable. The AC losses in the bulk and their influence on the trapped magnetic field are dependent on the temperature. Therefore, to estimate the efficiency and decay of the trapped magnetic field at various operation temperatures, it is necessary to know the temperature dependence of the AC losses. We investigated AC loss characteristics of a bulk at various temperatures. In the work, AC losses were measured for the amplitude of the AC external magnetic field up to 0.08 T and frequency 17.3 Hz/spl sim/62.2 Hz at the temperature 65 K/spl sim/100 K. It is also shown that the temperature dependences of the AC losses are well estimated by a theoretical model based on the Bean model.

In our previous work, it was observed that trapped magnetic field in an high-temperature superconductor (HTS) bulk was decayed and even erased by application of AC external field whose amplitude was much smaller than the peak value of the trapped magnetic field. Therefore, knowledge on the mechanism of the decay of the trapped magnetic field is important to design the machines and to develop a method to suppress the decay. This work studies a mechanism of the decay due to application of AC magnetic field by a numerical analysis and experiments. An analytical model is proposed to explain the mechanism based on the thermal effect due to AC losses in the bulk. In the model it is assumed that the AC loss characteristic follows the Bean model, which was experimentally demonstrated also in our previous work. We conducted experiments in which temperature rise of the bulk was measured by thermocouples and the decay of the trapped magnetic was observed by a hall probe. Results numerically calculated from the analytical model well agreed with those obtained from the experiments and we consider it was clarified that the decay of the trapped field was caused by the thermal effect due to AC loss. Once the mechanism has been clarified, methods to suppress the decay can be easily developed.

A trapped magnetic field in a bulk is decayed and even erased by the application of an AC external magnetic field whose amplitude is much smaller than the trapped magnetic field. In the paper an analytic model to describe behavior of the trapped magnetic field is proposed assuming that its decay is caused by thermal effect due to AC losses in the bulk. The proposed model well explains AC loss characteristics, temperature rise and the decay of the trapped magnetic field of the bulk. Based on the proposed model, methods to suppress the decay of the trapped are shown and the effectiveness of the methods is shown.

The trapped magnetic field in a bulk is decayed and even erased by the application of the AC external magnetic field whose amplitude is much smaller than the trapped magnetic field. In the previous work, an experimental result showed that the decay of the trapped magnetic field was due to temperature rise of the bulk caused by the AC losses. Based on this result, it is considered that the decay can be suppressed by (a) improvement of the cooling of the bulk and (b) reduction of the AC losses. We verified the effectiveness of these methods by conducting an experiment using a recently developed metal impregnated bulk which has high critical current density and improved thermal conductivity.

The magnetization property is one of the key issues when considering the accelerator-magnet applications of Bi-2212 wires. In this work, first, the critical current densities of several types of Bi-2212 round wires were measured by the transport current method at various temperatures. Then, the magnetization of the wires was measured at various temperatures and applied field amplitudes using the SQUID magnetometer. Hysteresis loops were plotted, and the time decay of the magnetization was studied. It was observed that magnetization had various values, but the hysteresis curves and time decays of all samples had the same tendency. The equivalent filament diameter can be determined from the measured magnetization and the measured critical current density. The equivalent filament diameters are several times larger as compared with the actual filament size.

The 'fishbone' fast wave travelling wave antenna was developed for LHD to provide a capability for rotational transform profile control by current drive. The fishbone antenna is equivalent to two combline antennae stacked vertically. The antenna operates around 75 MHz and excites a wavenumber of 14 m−1 when the phase difference between adjacent current straps is 90°. A test of a combline antenna with plasma load on the TST-2 spherical tokamak suggested the possibility that this type of antenna does not need to be installed in the immediate vicinity of the last closed flux surface. Optimization of the design was performed based on measurements on mock-up antennas and model calculations. In the fishbone antenna, controlled excitation of the even mode (with currents in the top and bottom halves of a current strap in the same direction) is necessary. A predominant excitation of the even mode was realized in the LHD fishbone antenna with simulated loading by selecting an appropriate operating frequency.

SUMMARYThis paper describes the formation process and chemical state of adsorbates produced during the two-step catalysation pre-treatment prior to electroless deposition. Tin species adsorbed during sensitisation are divided into two types, namely one that adsorbs weakly and one that adsorbs strongly. The former exists in equilibrium with Sn2+ in the sensitising solution. It easily desorbed from the substrate during the following HCl immersion, and the loss is recovered during an ensuing sensitising step. The latter is not desorbed during the HCl immersion step. A dry process after sensitisation, which should promote oxidation, induces the transition from Sn2+ to Sn4+. In the activating step, two reactions proceed independently of each other; that is, an oxidation-reduction reaction between Sn2+ and Pd2+ takes place, which produces Pd0 and Sn4+. Simultaneously, some Sn2+ is desorbed from the substrate. XPS analysis confirms that tin oxide (or hydroxide) and metallic palladium are the final products in th...

The four-beam correlation method has a potential of measuring fine-scale fluctuations locally. In the method, many lines of sight are measured and the coherences among them are calculated. As a proof of principle experiment, a visible fluctuation measurement system has been fabricated and applied to the TST-2 spherical tokamak plasma. Using this system, fluctuations were measured and high-frequency components (100±12.5 kHz) were analyzed. Because of a long parallel correlation length, local information was not obtained directly. However, comparison of the experimental results and those of a model calculation suggests that (i) the fluctuating emission is relatively localized in the peripheral region of the plasma, (ii) the perpendicular correlation length is of the order of 1 cm, while the parallel one is much longer than it and (iii) the magnetic field angle in the peripheral region agrees with that estimated from magnetic measurements.

In our previous work it was observed that trapped magnetic field in a YBCO bulk was decayed and even erased by application of AC external field whose amplitude was much smaller than the peak value of the trapped magnetic field. To study a reason for decay we investigated temperature rise of a YBCO bulk subject to the AC external magnetic field by use of thermocouples. A case was observed that the temperature rise of the bulk reached almost the critical temperature. This result shows that the decay of the trapped magnetic field was related to the temperature rise due to AC losses in the bulk.

Various types of MHD events including internal reconnection events are studied on the TST-2 spherical tokamak. In weak MHD events no positive current spike was observed, but in strong MHD events with positive current spikes, a rapid and significant impurity ion temperature increase was observed. The decrease in the poloidal magnetic energy is the most probable energy source for ion heating. The plasma current shows a stepwise change. The magnitude of this step correlates with the temperature increase and is found to be a good indicator of the strength of each event.

Electric motors and actuators are most promising future applications of HTS bulks. The HTS bulks in these electric machines are exposed to AC magnetic field perturbations. The perturbations cause AC losses in the bulks and also affect the magnetic field trapped in the bulks. In a previous work we measured AC losses in a YBCO bulk subject to the AC magnetic field and found the loss characteristics well followed the Bean model. In this work we experimentally studied the influence of the AC perturbations of the external magnetic field on the trapped field in a YBCO bulk. The experimental results showed that the application of the AC magnetic field decreased the trapped magnetic field even to zero. In this paper, the experimental results are presented and a reason for the decay of the trapped magnetic field is discussed based on the Bean model.

A new electron Bernstein wave emission diagnostic consisting of a heterodyne radiometer and a reflectometer was installed on TST-2. The instrument has a frequency range from 5 to 12 GHz which covers partially the fundamental and fully covers the second and third harmonic emissions. X-mode emission perpendicular to the flux surface, generated by B–X–FX mode-conversion scenario, is measured. The mode-conversion efficiency is calculated using a one-dimensional full-wave code with the density profile obtained simultaneously from the reflectometer, and the electron temperature (Te) is estimated. The levels corresponding to the 100–150 eV range are measured from the plasma core region, and the mode-conversion efficiency is calculated to be 0.5–0.8, leading to Te of approximately 200 eV. In addition, it is found that the reflectivity measured by the reflectometer is consistent with the calculated mode-conversion efficiency. This property can be used for a direct measurement of the mode-conversion efficiency.

Non-uniform current distribution in super-conducting magnet conductor causes serious deterioration of stability and increase in pulse field loss especially in large-scale conductors. To clear those problems we proposed the parallel sub-conductor system in which the main conductor was subdivided into sub-conductors arranged in parallel. Each of the sub-conductors is electrically insulated from the others and connected to an individual power supply. With this arrangement the current of each sub-conductor can be controlled separately and the current distribution in the sub-conductors can be actively controlled. We performed an experiment using a magnet wound of four-parallel sub-wires and demonstrated that the current distribution was quickly controlled and the magnet was actively stabilized by transferring the current from quenching sub-wire to the other sub-wires.

Round high Tc superconducting wires are sometimes preferred to flat tapes, because they are easy to assemble to obtain large current carrying capacity, and their performance in the external magnetic field is isotropic. Ag- or Ag/Au-sheathed Bi-2212 round wires were fabricated by the stranded-and-formed method. In this method, first, 54 filaments are bundled to make a segment, and then, three segments are stranded, drawn, and formed to a final round-shape wire. Advantages of the round wires fabricated by the stranded-and-formed method include higher tolerance against bending strain and higher critical current density than usual round wires. Another potential advantage of this type of round wires is the reduction of AC losses due to their multiply twisted structures. The magnetization losses of four types of the Bi-2212 round wire with multiply twisted structure were measured. The effect of the multiply twisted structure for the AC loss reduction was confirmed by the experimental results.

A superconducting joint technology used for high-temperature superconductors (HTS) is the key for enabling persistent operation of HTS magnets. In the present work, we have succeeded in developing a superconducting joint between REBCO-coated conductors (CCs) using a joint strap with a microcrystalline GdBCO precursor intermediate layer. Heat treatment and oxygen annealing, with a total processing time of less than 1 d, grows a biaxially-textured intermediate layer to connect the GdBCO layers in the CCs. Microstructure observation of a part of the joint cross-section with SEM and TEM showed that the intermediate layer and the GdBCO layers in the conductors were atomically connected. An electron backscatter diffraction result showed that both the c- and a-axis misorientations among the GdBCO layers of the joined conductor and the GdBCO layer of the joint strap were about less than 5°. This intermediate grown superconducting joint gives a critical current of >100 A at 77 K in a self-field. A critical current of a joint at 4.2 K in a self-field is seven times higher than that at 77 K. The persistent field decay of a small double pancake coil, terminated with this joint, showed a joint resistance in the range of

We examined the association between green tea consumption and mortality due to all causes, cancer, heart disease, cerebrovascular disease, respiratory disease, injuries, and other causes of death in a large-scale population-based cohort study in Japan.We studied 90,914 Japanese (aged between 40 and 69 years) recruited between 1990 and 1994. After 18.7 years of follow-up, 12,874 deaths were reported. The association between green tea consumption and risk of all causes and major causes of mortality was assessed using the Cox proportional hazards regression model with adjustment for potential confounders.Hazard ratios for all-cause mortality among men who consumed green tea compared with those who drank less than 1 cup/day were 0.96 (0.89-1.03) for 1-2 cups/day, 0.88 (0.82-0.95) for 3-4 cups/day, and 0.87 (0.81-0.94) for more than 5 cups/day (P for trend.001). Corresponding hazard ratios for women were 0.90 (0.81-1.00), 0.87 (0.79-0.96), and 0.83 (0.75-0.91; P for trend.001). Green tea was inversely associated with mortality from heart disease in both men and women and mortality from cerebrovascular disease and respiratory disease in men. No association was found between green tea and total cancer mortality.This prospective study suggests that the consumption of green tea may reduce the risk of all-cause mortality and the three leading causes of death in Japan.

Photovoltaic (PV) systems and other dispersed power systems need to be connected to a utility power grid for the systems to work effectively as energy sources. Protection against islanding is one of the most important techniques to develop for the dispersed power systems supplying surplus power back to the utility power grid. It is considered that active methods where the outputs of the power systems are actively perturbed are necessary to detect islanding. Various active methods have been developed. It has been shown that these methods work when a single power system is connected to one power distribution line. However, most of these methods have a limit in detecting islanding when multiple power systems are connected to one distribution line. In this paper, we compare the detection characteristics of typical active methods, frequency shift methods, a pulse perturbation method and a method using a correlation technique by simulation analysis for the case of multiple PV power systems. The study shows that the method using the correlation technique is the most promising when multiple power systems are operated on one distribution line.

Dynamic relaxation of the XY model quenched from a high temperature state to the critical temperature or below is investigated with Monte Carlo methods. When a non-zero initial magnetization is given, in the short-time regime of the dynamic evolution the critical initial increase of the magnetization is observed. The dynamic exponent $\theta$ is directly determined. The results show that the exponent $\theta$ varies with respect to the temperature. Furthermore, it is demonstrated that this initial increase of the magnetization is universal, i.e. independent of the microscopic details of the initial configurations and the algorithms., Comment: 14 pages with 5 figures in postscript

All stereoisomers with regard to C-1 and 2 of 1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP) analogue containing unsaturated (β-valienamine) and saturated 5a-carba-β- d -glucopyranosylamine (β-validamine) residues in place of morpholine moiety were synthesized. Although PDMP is a potent and specific glucosylceramide synthase inhibitor, the former valienamine analogues (4a-d) have been shown to be strong glucocerebrosidase inhibitors ( IC 50 3–7 ∗x 10 −7 M). The latter validamine analogues (5a-d) were also moderate glucocerebrosidase inhibitors ( IC 50 5–20 ∗x 10 −6 M). A series of compounds synthesized lacked an inhibitory potency against the glucosyltransferase at all. Whereas the analogue 6a composed of epimeric α-valienamine residue did not possess any potency against both enzymes.

The spectrum and the level of fluctuation have been evaluated from the phase data obtained with a reflectometer during the period without phase runaway on the JFT-2M tokamak. The estimated fluctuation level is about 1% in OH mode (at r a ), about 4% in L mode (at r a ≈ 0.8 ) and about 10% in H mode ( r a > 0.9 ), while the measured position changes according to the density profile.