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A unique activation technique for permanent Nd-Fe-B magnets which were embedded in the rotors of interior permanent magnet (IPM) motors has been developed as a magnetizing tool with use of high temperature superconducting (HTS) bulk magnet. The experimental and numerical simulation studies were conducted to evaluate the magnetic field-trapping performances of the rotor of air-conditioner compressor in the hybrid-type automobiles. The sample rotor containing six demagnetized permanent magnet plates were exposed in the intense static magnetic fields above the magnetic pole which contained the bulk magnet generating over 4 T. As a result, the sample magnets were perfectly magnetized in the static magnetic field. The precise simulation on the flux distribution in the rotor clarified that it is important to make the flux direction in the rotor core and the easy magnetization axis of PM identical. We convinced this activation technique should enable us to promote the degrees of freedom of motor designing and its processing.

In a high-temperature superconducting (HTS) multi-layer AC cable, each layer of HTS tape is twisted cylindrically and exposed to the AC magnetic field produced by the AC transport current in the other layers. The magnetic field consists of a circumferential magnetic field and a longitudinal magnetic field. The magnetic field of each layer serves as an external magnetic field to the other layers. We measured the AC losses in twisted cylindrical samples comprising single layers of HTS cable transporting AC currents in external circumferential and longitudinal magnetic fields. The amplitude and direction of the combined magnetic fields were controlled via modifying the balance between the circumferential and longitudinal magnetic fields. We investigated the influence of the twist angle, and amplitude and direction of the magnetic field on the AC loss characteristics.

International audience; The magnetic flux dissipation from the MgB 2 bulk magnets during pulsed field magnetization (PFM) processes has been estimated for the samples fabricated by hot-pressing (HP) and spark plasma sintering (SPS). We defined the parameters as field penetration ratio B P /B a and the field trapping ratio B T /B P to evaluate the flux motion and performance. The data plots of trapping ratio B T /B P showed us two regions which originate from the fast flux flow and flux jump. The field trapping performance was drastically degraded when the flux jump happened. Flux jump happened at various times after the peak field. A very late flux jump happened at 420 ms which severely degraded the trapped field. This time delay, much larger than the heat propagation time in the MgB 2 sample, remains to be explained.

We produced HTS capacitors using two HTS tapes as electrodes. We observed that the current increased with frequency when fixed voltage was applied, thereby demonstrating the capacitance characteristic. In addition, changes in the dielectric layer and length of the HTS capacitor tape exhibited the same trend as those for regular capacitance. We tested directional changes of the transport current, using “same direction mode,” and “opposite direction mode.” In the opposite direction mode, the magnetic field was canceled and the inductance was nonexistent. In the same direction mode, we observed that the characteristic of the capacitor included the inductance in series. We clarified the fundamental HTS capacitance characteristic.

We measured the ac losses in each layer of a three-layer twisted high-temperature superconducting cable. The currents in each layer were controlled using three power supplies and the transport current balance and phase could be varied. Longitudinal magnetic fields were produced by the transport currents in the outer layers and circumferential magnetic fields were produced in the inner layers of the cable. The amplitude and direction of the composition magnetic fields changed according to the distribution of the transport currents in each layer. The critical currents in each layer were different; hence, the ac loss in each layer could not be compared. We measured the influence of the electromagnetic conditions in a layer by varying the transport current balance in the other layers. We also transported current in the “single-phase mode” and “three-phase mode,” and measured the losses in each layer.

This paper reports the design, fabrication, and test results of a 50-kW-class fully superconducting induction/synchronous motor for transportation equipment. Its maximum speed is 1800 rpm, and both rotor and stator windings were fabricated using Bismuth strontium calcium copper oxide tapes. The so-called ring-winding structure was used for the stator windings to improve the critical current of the stator windings in the core. The fabricated motor was immersed in liquid nitrogen and tested using a commercial pulse width modulation inverter. We successfully carried out a 3-kW load test at a synchronous speed of 1800 rpm. Furthermore, a variable speed test under light load conditions was also completed.

Study on ac loss characteristics of HTS coils with an iron core to simulate an armature winding of ac rotational machine and a method to reduce ac losses in HTS coils combined with the iron core in 3-phase condition are reported in this paper. In this study, the 3-phase test model which combines 6 HTS coils wound by YBCO tapes and the iron core used for an armature of conventional induction motor is fabricated for the ac loss measurement. It is shown that the measured ac losses in the 3-phase condition coincides with the sum of the ac loss of each phase measured in the 1-phase condition. The effectiveness to suppress the perpendicular magnetic field applied to the tape in the coil by use of magnetic materials around the coil winding on the ac loss reduction in the 3-phase condition is investigated. The measured ac loss with placing the magnetic material around the coil winding in the slot of the iron core remarkably decreases. The results of the numerical magnetic field analysis confirmes that the perpendicular magnetic field significantly decreases by arranging the magnetic material and supportes the validity of the measurement results. The results obtained in this study demonstrates that the effectiveness to modify the magnetic field distribution by use of the magnetic material around the coil winding on the ac loss reduction in 3-phase HTS coil combined with the iron core.

Feasible applications in the industrial regions for the bulk high-temperature superconducting (HTS) magnets have been investigated in two categories of the strong magnetic field generators and the magnetic levitation devices by active and passive field trapping, respectively. When we adopt the system to the active field generators, magnetization procedures are necessary. The authors have studied the field-capturing abilities of the HTS bulk magnets on two ways of the activation procedure and the material designing. In the former, we clarified the magnetic flux behavior that invades into bulk magnets, and that the invading flux motion is affected by the previously existing flux distribution. Therefore, the magnetic flux can be accumulated with successive magnetic fields applications with descending heat generation in order. In the latter, the selective magnetic field invasion was observed between wide- and narrow-growth sector regions. Since the bulk magnets with steep magnetic field distributions deform their own field distribution shape to be uniform by the shielding effect when the ferromagnetic plate was attached on the magnetic pole, we have succeeded in obtaining the uniform magnetic field of several-hundred parts per million in the space between the magnetic poles.

IntroductionThe optimal target of mean arterial pressure (MAP) for better outcomes in patients with vasodilatory shock remains a matter of debate. Although catecholamines are generally used to maintain target blood pressure in hypotensive patients with vasodilatory shock, the adverse effects of catecholamines must also be considered. We will perform a systematic review and meta-analysis of randomised controlled trials (RCTs) to assess the certainty of evidence determining the optimal target of MAP control for patients with vasodilatory shock in critically ill settings.Methods and analysisThis study protocol was registered in the University Hospital Medical Information Network Clinical Trials Registry. We will include only RCTs that evaluated the two different comparators for target MAP to be maintained for clinical outcomes of all-cause mortality: organ dysfunction and adverse events in critically ill adult patients with vasodilatory shock. We will search the electronic bibliographic databases of MEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials in November 2020. Two reviewers will independently screen titles and abstracts, perform full article reviews and extract study data. We will report study characteristics and assess methodological quality using the Cochrane Risk-of-Bias 2 tool. If pooling is appropriate, we will calculate relative risks with 95% CIs for all outcome measures. Clinical and methodological subgroup and sensitivity analyses will be performed to explore heterogeneity. Overall certainty of evidence will be evaluated using the Grading of Recommendations Assessment, Development and Evaluation approach.Ethics and disseminationThis study will not involve primary data collection, and formal ethics approval will therefore not be required. We aim to publish this systematic review in a peer-reviewed journal.Trial registration numberUMIN000042624.

International audience; When the MgB2 bulk body is magnetized by the pulse magnetizing method, the MgB2 bulk can take the role of a pseudo permanent magnet. However, it was confirmed that the temperature at which MgB2 is expected to be used is close to the critical temperature (TC) of MgB2 and the specific heat is small, so that the heat generated by the pulse magnetizing method causes flux jump and the trapped magnetic field performance deteriorates. In this study, pulse magnetizing was performed on different samples to verify and consider changes in the trapped magnetic field performance. As the sample, the sample obtained by changing the amount of titanium added was synthesized by uniaxial hot pressing and the sample synthesized by spark plasma sintering (SPS). Figure (a) shows a comparison of the trapped magnetic fields of the samples synthesized by the uniaxial hot press. From Fig. (A), it was shown that the capture magnetic field performance may be improved or deteriorated by the composition ratio of the material, the addition of impurities, and the method of synthesizing the bulk material.

In this paper, we suggest a new magnetization loss model for all magnetic field directions. We measured three types of HTS tapes, two different critical current Bi2223/Ag tapes, and an YBCO tape to compare the measurement with the magnetization loss model. Our new model is based on the measured magnetization losses, because the loss is affected by the intrinsic critical current distribution and the cross-section. The studied conditions of the base magnetization losses are: the magnetic field applied perpendicular to the tape axis and perpendicular to the tape face, perpendicular to the tape axis and parallel to the tape face, and parallel to the tape axis. This model enables us to describe magnetization losses in response to a change in the amplitude of the magnetic field, the angle of the tape axis, and the angle of the tape face.

We measured the influence of the twist pitch, twist direction, and transport current balance of the inner and outer layers on the ac loss characteristics in a two-layer twisted high temperature superconducting (HTS) cable. To measure the ac loss in each layer, we placed the thermo-couples on each tape face with thermal insulation. In the HTS cable, the inner layer is exposed to a longitudinal magnetic field generated by the twisted outer layer, and the outer layer is exposed to a circumferential direction magnetic field generated by the inner layer. When the inner and outer layers connect in series, the ac loss characteristics in the inner layer exhibit the influence of the outer layer arrangement. When the transport current balance of the inner and outer layer changes, the lowest loss condition exists when the inner transport current exceeds the outer transport current. These phenomena are possible explanations for the amplitude and direction of the magnetic field in each layer.

DC induction heating with a superconducting magnet has the capability to melt metal in a short time. We have been investigating high-temperature superconductor coils using REBCO-coated conductors to apply to dc induction heating. In order to obtain a large magnetic field for the aluminum melting examinations, we designed, prepared, and evaluated a split coil. The split coil pair was comprised of three rectangle-shaped double pancake coils on each side. The lengths of the outer short and long side and the inductance of each coil winding were about 270, 340 mm, and 200 mH, respectively. A coil winding contains about 700-m REBCO tapes. The arrangement of six coils was determined by their transport properties at liquid nitrogen temperature. The split coil pair was cooled by conduction cooling and evaluated the coil properties evaluated by excitation. It was confirmed that the split coil successfully generated the magnetic field according to design. The temperature of the coil was guessed at about 50 K according to the magnetic field dependence of the critical current at various temperatures for the tapes used in the split coil pair. We observed aluminum melting, although incomplete, after a rotation of 1200 r/min in 100 s, with a coil current of 114 A in the aluminum melting test. These results suggested the effectiveness of the REBCO split coil to the aluminum melting process but there is a room to improve the split coil especially as the conduction cooling.

MgB 2 bulk magnets are one of the attractive bulk superconductors because they have homogeneous trapped field distribution, low material costs, lightweight, and so on. Pulse-field magnetization (PFM) also has some effective advantages in the point of view of compact setup, shorter magnetizing time, and an inexpensive way to magnetize the bulk samples. However, the trapped field by PFM is inferior to those by field cooling magnetization due to the heat generation caused by sudden changes of the magnetic flux motion. Especially, the temperature rise is remarkable for MgB 2 bulk magnets because of its low specific heat. In this study, we have carried out the PFM technique for five-stacked or three-stacked MgB 2 bulk samples to analyze the flux-invasion behavior. These samples were fabricated by ball-milling and hot-pressing. As a result, maximum trapped field of B T = 0.64 T was obtained at 14.6 K at the center of the topmost sample when the external magnetic field B ex of 0.90 T was applied. As B ex increases further, B T were dramatically decreased because of heat generation. Furthermore, flux jumps frequently took place in the applied field higher than 2.0 T.

In this work, we exposed a high-temperature superconducting (HTS) tape to a rotating magnetic field, and measured ac losses using a calorimetric method based on the temperature rise caused by the ac loss. To compare the characteristics of the other ac loss conditions, we measured the magnetization losses in the uniform ac magnetic field perpendicular and parallel to the HTS tape face. The losses in the rotating magnetic field are the same as in the perpendicular magnetic field. In addition, we measured the influence of the rotating magnetic field waviness on the ac loss characteristics.

We report the ac loss characteristics of stacked HTS tapes in an iron core. To estimate the loss distribution, we measured each stacked HTS tape using a calorimetric method. To clarify the influence of an iron core, we measured the ac losses of the stacked HTS tapes without the iron core. The ac transport current losses of the stacked HTS tapes positioned in the iron core were greater than those without the iron core. The distribution of the magnetization losses by the leakage magnetic field was that the loss at the outside of the HTS tape was highest because shielding current prevented the magnetic field from penetrating to the inside of the stacked HTS tapes.

A characteristic magnetic separation technique has been developed to recycle the Ni resource from the waste fluid of electroless Ni-plating processes. Since the plating waste still contains high concentration of Ni ions after several cycles of plating processes, the magnetic separation experiments were conducted to collect the precipitates containing Ni compounds. After extracting the fine NiHPO 3 precipitate from the waste liquid, we synthesized the NiSO 4 crystals from the NiHPO 3 precipitates through the reaction with the concentrated sulfuric acid. The open-gradient magnetic separation was employed to separate the NiSO 4 crystals from the mixed slurry composed of the NiSO 4 and the NiHPO 3 due to the difference between their magnetic properties. The experiments were practically conducted with use of the Gd123-based HTS bulk magnets with very steep gradient of magnetic field of over 100 T/m, which were activated to the magnetic fields of 1.53 and 1.95 T by the pulsed field magnetization process operated at 35 K. The ratio of NiSO 4 content in the collected slurry attracted to the magnetic poles reached up to 98%, which suggests that the paramagnetic NiSO 4 crystals are preferentially collected by the magnetic force from the mixed slurry in the strong magnetic field generated by the HTS bulk magnet.

The fundamental study on the ac loss reduction in high-temperature superconducting (HTS) coils for armature windings of ac rotational machines is presented in this paper. In this paper, a simplified model that simulates a part of the distributed armature winding of ac rotational machines is used. For the ac loss reduction, we study a method to reduce the perpendicular magnetic field applied to the tape surface in the coil by arranging a magnetic material around the coil winding. The numerical magnetic field calculation shows that the perpendicular magnetic field clearly decreases by arranging the magnetic material around the coil winding in the slot of the iron core. To investigate the effect of the insertion of the magnetic material on the ac loss reduction, we fabricate the measurement setup using the test HTS coils wound by a Bi2223 tape and a YBCO tape, combined with the laminated iron core. The transport ac losses in the test coils are measured by changing the arrangement of the magnetic material. The measurement results demonstrate well the ac loss reduction by use of the magnetic material around the coil winding in the slot of the iron core.

The magnetic flux invasion into the Dy123-based HTS bulk magnets were experimentally evaluated during the pulsed field magnetization processes. Since the invasion of the magnetic flux into the sample would be expected to be affected by the J c distribution, we estimated the differences of the magnetic flux motions between the growth sector boundary (GSB) and the growth sector region (GSR) by measuring the changes of magnetic flux density and temperature during the pulsed field application of 5 T at 30 K. The experimental results on the temperature measurement showed that the magnetic flux invades into the sample through the path in the GSR prior to that in the GRB region. Furthermore, the changing rate of magnetic flux gradually changed with the position on the GSR, while they irregularly changed and did not exhibited any tendency on the GSB. This means that the magnetic flux straightly invades the sample from GSR heading for the center portion, while it does not uniformly flow on the GRB. As a result, the heat generation occurs in the GSR area prior to the GSB region. The magnetic flux invasion behavior exhibits selective and nonuniform motion, reflecting the difference of the macrostructure on the GSR and the GSB.

The billet heating technique by rotating conductive material in a magnetic field for aluminum extrusion has been reported, but metal melting technology by the induction heating with the dc magnetic field has not. Further complex geometries of aluminum profiles are formed by the casting that requires highly efficient metal melting technology. In order to verify the capability of induction heating using dc superconductor coils for metal melting in the casting process, we performed a metal melting experiment with the small examination equipment in a magnetic field. The small examination equipment consists of a motor, a heat insulation structure, a rotating shaft, a specimen holder, a frame, and others. An aluminum pipe of about 0.77 kg, where its outer diameter was 180 mm and its inner diameter was 170 mm, was put into the examination equipment. A dc magnetic field, ranging from about 1 T at the nearest point to 0.4 T at the furthest point, was applied to the pipe by the superconductor magnet. The temperature of aluminum exceeded 500 °C within 2 min by the rotation of the pipe at 800 r/min. Aluminum melting in the sample holder was observed after the rotation of 1200 r/min in 90 s, and some amounts of melted aluminum rose over the sample holder and sputtered out by centrifugal force. These results indicate that induction heating with the superconductor coils can supply melting metal of required amount in a short time.

The authors have been attempting to obtain the uniform magnetic field distribution in the space between the face-to-face HTS bulk magnets. The magnetic poles containing the HTS bulk magnets are usually characterized as non-uniform magnetic field distribution. Since the distributions show the conical or convex shapes, it is difficult to obtain the uniform magnetic field spaces even when the magnetic poles would be placed face-to-face. The authors have modified the shape of the distribution of one-side magnetic pole by attaching an iron plate on the surface, and formed the concave magnetic field distribution on the pole surface. The steep concave or convex distributions at each pole surface change to be flat with increasing distance from the pole surface. After the experimental result recording the best uniformity of 358 ppm by combining the concave and convex field distributions face-to-face, we attempted to simulate the feasible performance in this configuration. In the numerical simulation, the concave field distribution modified by attaching an imaginary spiral coil on the pole surface was coupled with the original convex field. We succeeded in obtaining the best uniformity of 30 ppm at 1.1 T in 4 x 4 mm2 x-y plane at 7 mm distant from the pole surface in the gap of 30 mm. This result suggests that the concave and convex magnetic field distributions compensate the field uniformity with each other with keeping the magnetic field strength in the gap, and also suggests the novel compact NMR/MRI devices in the future.

A novel magnetizing technique for permanent magnets (PMs) embedded in the interior permanent magnet (IPM) motors has been proposed as a safer and more effective process than the conventional processes using copper pulse-coils. In the new process, the high temperature superconducting (HTS) bulk magnet emitting intense magnetic field of over 3 T was employed to activate the rotor and PMs inside. A magnetic pole containing the HTS bulk magnet was scanned on the surface of IPM rotor, resisting against the extremely strong attractive force between the magnet and rotor. Following the experiments in the past, the numerical simulation studies have been conducted to evaluate the magnetic field-trapping performances of the PMs. In this study, the numerical analysis of the magnetization behaviours was conducted for the PMs embedded in the rotor of the commercial air-conditioner motor in the hybrid car. The simulation results showed us that the demagnetized Nd-Fe-B plates in the rotor were fully magnetized in the intense static magnetic fields on the magnetic pole containing the HTS bulk magnet. The magnetizing behaviour in this peculiar magnetizing operation was understandable by estimating the anisotropic easy-direction of the PM plates embedded in the rotor. The novel activation method for PM is characterized as a no-shock and no-heating method, which would promote the degree of freedom on the IPM motor designing.

The magnetic flux capturing of MgB2 bulk magnets made by spark plasma sintering process has been precisely investigated to clarify the mechanism of flux motions during the pulse-field magnetization processes. The field trapping ratio B T/B P was evaluated as a key parameter of field trapping ability which strongly relates to the heat generation due to the rapid flux motion in the samples. The time dependence of magnetic flux density revealed the actual flux motion which penetrated the samples. The trapped fields B T and field trapping ratios B T/B P of various samples were classified into three regions of ‘no flux flow’, ‘fast flux flow’ and ‘flux jump’ according to the generation of heat and its propagation. A flux jump was observed late at 280 ms from the beginning of PFM process, while the field penetration B P showed its peak at 10 ms. Considering the heat propagation speed, the long-delayed flux jump should be attributed to the macroscopic barriers against the heat propagation to the surface centre of bulk magnet.

In order to clarify the behavior of the magnetic flux that invade into the melt-processed Dy123-based high-temperature superconducting bulk magnet, the motions of magnetic fluxes and the phenomena of heat generation were precisely measured during the pulsed field magnetization processes. In the experiments, we estimated the time evolutional profiles that were measured at two portions in the growth sector region and the growth sector boundary. They are characterized as the areas of lower and higher critical current densities than each other, respectively. The serial pulsed magnetic fields of 5 T were applied to the sample at 30 K, and the data were obtained in turn by the Hall sensor and thermometer that were put at several positions along the radial rows on the growth sector boundary and the growth sector region. The profiles of magnetic flux during the pulsed field application actually proved that the magnetic flux invades the sample through the growth sector regions in shorter time and with stronger magnitude than through the growth sector boundaries. Since the low magnetic field application leads to low heat generation, it is expected to achieve the higher trapped field performances than ever.

To optimize pulse field magnetization processes for high-temperature superconducting (HTS) bulk magnets, it is important to control the magnetic field amplitude and the driving temperature. Many publications have reported on the experimental and numerical results of the pulsed-field magnetization method. In the numerical method, the HTS bulk properties are modeled to simplify the calculations, examples being the Bean model and the Kim model, etc. During pulsed-field magnetization the critical current density in the HTS bulk changes dramatically due to the magnetic field and temperature rise induced by the ac losses. For these reasons these properties are key to the analysis of the pulsed-field magnetization process, which is calculated using the measured practical HTS bulk properties, and these results show different temperature rise and trapped magnetic field characteristics. We assumed that HTS bulk has intrinsic deterioration in practice. Therefore, we recalculated using the adjusted parameters, and these analytic results correspond with the experimental results.

For economic reasons high-temperature superconductor (HTS) machines, such as HTS motors and generators, are designed to use an iron core to reduce the HTS tape length. In these situations, the HTS tapes are positioned in the iron core and transport the ac current within the ac leakage magnetic field. We investigated the influence of the iron core arrangement on ac loss characteristics. We modified the iron core of a transformer by removing a rectangular segment and then positioned an HTS tape in the rectangular recess created. The iron core was affected by the ac magnetic field generated by the ac coil, and the HTS tape transporting the ac current. We placed the HTS tapes in different rectangular positions and varied their shape. In all conditions, the ac transport current losses were greater than losses experienced when the HTS tapes were situated without the iron core, and the ac leakage magnetic fields produce ac magnetization losses. Therefore, how the HTS tape is arranged in the iron core affects the ac loss characteristics and merits further study.

The magnetic field distributions of an HTS bulk magnet system were precisely measured between the face-to-face 3.4-T magnetic poles. After the activation by 5-T field cooling magnetization, the magnetic flux density has reached the value of 2.26 T at the center of the 34-mm gap. The sum of the local magnetic fields generated from each magnetic pole coincides with the local field strength in the gap. We estimated the homogeneity of the magnetic flux densities of Bz and By, which were measured at various positions along z and y-axes in the center portion of the 60-mm gap. Since the magnetic flux density becomes smooth with increasing distance, we obtained the smallest distribution range of 123 ppm of Bz = 1.62 T at the center of the gap as for Bz. On the other, as for By, the smallest distribution range of 1125 ppm of Bz = 1.20 T was obtained at z = 1.7 mm distant from the center point. Since there must exist a certain plane which has no vector components along the radius direction at the center of the gap, the closer the z-positions come to the null point, the more homogeneous the field distribution becomes.

Single-pancake coils having different winding turns are fabricated. The bobbin material used for the coils is a Dyneema fiber-reinforced plastic (DFRP), which has a thermal expansion property during cooling. The influence of the DFRP's expansion on thermal strains of the coil during cooling is experimentally estimated. In the experiment, the thermal strains on the superconducting tape of the outermost turns in the coils are measured. The dependence of epoxy impregnation on the thermal strain of the coil is also experimentally estimated. According to the experimental data, the combination of impregnation and the bobbin's expansion effectively decreases thermal contraction of the outermost tape.

The flux-invasion behavior into the melt-processed Y-Ba-Cu-O bulk magnets were precisely measured and analyzed during and after their pulsed-field magnetization processes operated at 30.6 K. The materials were fabricated as the bulk monoliths grown by adopting two seed-crystals, or shifting the seed-crystal positions from the centre of the sample surface, which exhibited the magnetically single-domain distributions. Although the performances of the trapped flux density after activations showed no obvious differences, the flux started invading into the sample bearing two seeds obviously at lower fields than those of normally-grown isotropic crystal. Since the flux penetration behavior were thus clearly different between the samples with the structure grown from two seeds and uniformly grown samples with a seed crystal, it is suggested that the structure results in an effective magnetizing method with less heating than those of conventional samples, which results in the higher performance of field trapping in the bulk magnets than usual.

The magnetic separation experiment to collect the Ni compounds from the waste liquid of electroless plating processes was conducted in the open-gradient magnetic separation process with the high temperature superconducting bulk magnet system. The magnetic pole containing Gd-based bulk superconductors was activated to 3.45 T at 35 K in the static magnetic field of 5 T with use of a superconducting solenoid magnet. The coarse Ni-sulfate crystals were formed by adding the concentrated sulfuric acid to the Ni-phosphite precipitates which yielded from the plating waste liquid by controlling the temperature and the pH value. The open-gradient magnetic separation technique was employed to separate the Ni-sulfate crystals from the mixture of the Ni-sulfate and Ni-phosphite compounds by the difference between their magnetic properties. And we succeeded in collecting Ni-sulfate crystals preferentially to the Ni-phosphite by attracting them to the magnetic pole soon after the Ni-sulfate crystals began to grow.

Aiming to develop the compact nuclear magnetic resonance devices, the authors have been developing the uniform magnetic fields in the space between the face-to-face magnetic poles which contain HTS bulk magnets. The authors deformed the original convex shape of the magnetic field distribution to concave by attaching a ferromagnetic iron plate of 20 mm and 100 mm in diameter on one of the pole surfaces. The magnetic field distribution precisely measured along x-axis changed from concave to convex with increasing distance from the magnetic pole surface, which suggested the presence of magnetically flat region. From the results of mapping on the field uniformity data, we have succeeded in obtaining the field uniformity under 500ppm in the space of 4 x 4 x 0.8 mm3 when the magnetic poles emitting concave and convex field distributions were settled face-to-face with various gaps 30-70 mm. This performance exceeded the target value of 1,500ppm which is necessary to detect the NMR signals.

In semiconductor devices, miniaturization of circuit patterning on wafers is required for higher integrations of circuit elements. Therefore, very high tolerance and quality are also required for patterning of microstructures of photo masks. The deposition of particulate dusts generated from mechanical bearings of the spin processor in the patterns of the photo mask is one of main causes of the deterioration of pattern preciseness. In our R&D, application of magnetic bearing utilizing bulk high temperature superconductors to the spin processors has been proposed. In this study, we develop a test spinner for the non-contact spinning process in the photo mask production system. The rotation test by using this test spinner shows that this test spinner accomplishes the improvement of the spinning ability compared with the test spinner developed in our previous study. This paper describes the rotation test results of the new test spinner applying the magnetic bearing with bulk high temperature superconductors.

The magnetic separation experiment for recycling the nickel-bearing precipitates in the waste liquid from the electroless plating processes has been practically conducted under the high gradient magnetic separation technique with use of the face-to-face HTS bulk magnet system. A couple of facing magnetic poles containing Sm123 bulk superconductors were activated through the pulsed field magnetization process to 1.86 T at 38 K and 2.00 T at 37 K, respectively. The weakly magnetized metallic precipitates of Ni crystals and Ni–P compounds deposited from the waste solution after heating it and pH controlling. The high gradient magnetic separation technique was employed with the separation channels filled with the stainless steel balls with dimension of 1 and 3 mm in diameter, which periodically moved between and out of the facing magnetic poles. The Ni-bearing precipitates were effectively attracted to the magnetized ferromagnetic balls. We have succeeded in obtaining the separation ratios over 90% under the flow rates less than 1.35 L/min.