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In the case of motors and generators, the benefits of using high-temperature superconducting (HTS) coils can be represented by the reduction of 50% in both losses and sizes compared to conventional machines. However, it is hard to establish quench detection and protection devices for the HTS coils applied to the rotors of motors and generators. Therefore, the stability of the coils is lower than for the quiescent coils applied to NMR, MRI, and so on. Therefore, it is important to improve the self-protection ability of HTS coils. We have studied the methods to improve the self-protection ability of HTS coils by removing the turn-to-turn insulation and inserting metal tape instead of the electrical insulation. When the coils are energized, there are voltages generated by sweep rate of the current (di/dt) and inductance of the coil. Because noninsulated HTS coils have electrical contacts along the transverse direction, a bypass current is generated along the transverse direction and noninsulated HTS coils have a risk of Joule heating in the stabilizer and metal substrate. Furthermore, the electrical contact resistance of noninsulated HTS coils was changed by a winding torque. In this paper, we measured the electrical contact resistance along the transverse direction with various winding torques for noninsulated HTS coils.

The high temperature superconducting (HTS) coils have very low normal zone propagation velocity (NZPV) and complicated quench behaviors. Because of these reasons, it is difficult to expect the self-protection. In this paper, two methods are suggested to improve the self-protection ability of HTS coils. One is to remove the insulation between turn–turn winding in HTS coils to enhance the thermal and electrical contacts along transverse direction and to increase the whole thermal stability of them. The other is Cu or Brass tapes are wound with HTS tape wire instead of the insulation to improve the thermal, electrical and mechanical stability of the HTS coils. To clarify the quench behaviors of the suggested coils, the normal zone propagation properties of the fabricated non-insulated HTS pancake coils were shown by measured voltage and temperature traces during the quench as a function of the operating temperature. And the characteristics of the normal transition and amount of the shared current to adjacent layers were quantitatively measured by a Hall sensor located at the center of HTS coils to measure the change of the self-magnetic field by operating current. The current sharing behaviors in the non-insulated HTS coil and the coil with Cu tape inserted were observed. The minimum quench energy (MQE) of the HTS coil with Cu tape inserted was the largest in the tested coils. It means that the HTS coil with Cu tape inserted had the highest transient stability against the thermal disturbances among the tested coils and the improvement of self protection abilities was proved.

NMR/MRI magnets have a protection device to prevent the damages due to a quench. On the other hand, the protection device design of HTS coils or magnets are very difficult because it has a very low normal zone propagation velocity (NZPV) and complicate behaviors of quench. We have studied the methods to improve the self-protection ability of HTS coils by removing the turn-to-turn insulation and inserting the metal tape instead of insulation. In this paper, the improved transient stabilities and self- protection abilities of HTS coils by removing the insulation and inserting metal tapes will be presented by minimum quench energy (MQE).

High temperature superconducting (HTS) coils wound with HTS wires have very low normal zone propagation velocity (NZPV) and complicated quench behaviors because the wires have a high thermal stability and large specific heat. According to these reasons, in case of HTS coils and magnets, it is difficult to expect the self-protection like low temperature superconducting (LTS) coils. In this paper, we suggest a method which can remove the insulation among turn-to-turn in the coil to improve the self-protection property of HTS coils. Because the thermal and electrical contacts along transverse direction are enhanced by no turn-to-turn insulation, the whole thermal stability of HTS coils begins to increase. Furthermore, although a quench occurs in the coil, it is possible to realize a self-protection of HTS coil because the current path of the coil is modified in order to avoid quenching. To confirm a quantitative evaluation for quench behavior of the suggested coil, we carried out the measurements with the coils having variety types of turn-to-turn insulation. The experimental results and the self-protection ability about the tested coils will be presented.

The electric device applications of a high temperature superconducting (HTS) bulk magnet, having stable levitation and suspension properties according to their strong flux pinning force, have been proposed and developed. We have been investigating a three-dimensional (3-D) superconducting actuator using HTS bulks to develop a non-contract transportation device which moves freely in space. It is certain for our proposed 3-D superconducting actuator to be useful as a transporter used in a clean room where silicon wafers, which do not like mechanical contact and dust, are manufactured. The proposed actuator consists of the trapped HTS bulk as a mover and two-dimensionally arranged electromagnets as a stator. Up to now, the electromagnets consisted with iron core and copper coil were used as a stator, and each electromagnet was individually controlled using DC power supplies. In our previous work, the unstable movement characteristics of HTS bulk were observed under the DC operation, and the AC electromagnets driven with AC controlled current was proposed to solve these problems. In general, the trapped magnetic field in HTS bulk was decayed by a time-varying external magnetic field. Thus, it needs to optimize the shapes of AC electromagnets and operating patterns, the decay properties of the trapped magnetic field in the HTS bulk mover by the AC magnetic field should be cleared. In this paper, the influences of the frequency, the overall operating time, the strength of magnetization field and drive current against the decay of trapped magnetic field were experimentally studied using the fabricated AC electromagnets.

Electric device applications of a high temperature superconducting (HTS) bulk magnet, having stable levitation and suspension properties due to their strong flux pinning force, has been proposed and developed. We have been investigating a three-dimensional (3-D) superconducting actuator using HTS bulks to develop a non-contract transportation device that moves freely in space. It is expected that our proposed 3-D superconducting actuator will be useful as a transporter used in a clean room where silicon wafers which dislike mechanical contact and dust are manufactured. The proposed actuator consists of an HTS bulk (trapped magnetic field by field cooling method) magnet for the mover and two-dimensional arranged multi-pole electromagnets as the stator. Up to now, the electromagnets consisted with ironed cores and copper coils were used as a stator, and each electromagnet was individually controlled using DC supplies. The movement of HTS bulk (mover) was not smooth because of the DC control. In this paper, the new electromagnets driven with AC control were proposed to improve the moving characteristics of the bulks. The characteristics of horizontal movement by newly proposed system will be presented.

In design and manufacture of a compact NMR (nuclear magnetic resonance) magnet which consists of a stack of high temperature superconducting (HTS) bulk annuli, spatial homogeneity and temporal stability of trapped magnetic fields are key issues. This paper presents a study on optimized configuration of stacked HTS bulk annuli for the compact NMR application. A three-stack bulk magnet was designed and tested at two different temperatures of 20 and 77 K, and two different background fields of 3 and 5 T. The test results were compared with analytic results to verify the validity of the calculation. Then, various optimized patterns were investigated numerically to find out an optimized stack pattern of HTS bulk annuli in a given condition. The results prove that with the proposed optimized method trapped field strength as well as its homogeneity of a bulk-annulus stack can be improved.

Wire-woven bulk Kagome (WBK) has recently been used to fabricate multi-layered truss-type cellular metals. A tube WBK structure is fabricated of tubes instead of solid wires. In this work, tube WBK specimens with various combinations of slenderness ratio and inner-to-outer diameter ratio of the tubular struts were tested under compression to investigate the effects of geometric factors on peak strength, equivalent Young′s modulus and energy absorption capability. To aid in the physical interpretation of the results and the development of a design methodology, numerical simulations of single tubular struts were performed with a wide range of slenderness ratio and inner-to-outer diameter ratio. The tube WBKs outperformed most cellular metals, but they were inferior to hollow trusses, especially those with a diamond configuration. However, energy absorption of the tube WBKs was comparable to that of hollow trusses because of stable deformation of the tube WBKs after initial yielding or maximum strength.

High temperature superconducting (HTS) motors electromagnetically consist of a rotator wound with HTS wires and an armature with conventional copper wires like Litz wire. The HTS rotor windings, as field coils, consist of a straight part and an end-ring part. Because a major rotation torque is induced by an interaction between magnetic fields and current-carrying conductors in the straight part, most of mechanical stresses in the motor occur at the straight part. An end-ring is placed in the edge of the straight part and used to connect to each adjacent straight-part coils. The magnetic fields by coil currents concentrate on the end-ring part, therefore, it is expected that the critical current of the entire coil, straight and end-ring, can be determined by the magnitude of the field in the end-ring. This paper deals with the overall Jc degradation in the end-ring part by self-field generated from the coil. In addition to electromagnetic analyses, we have performed a numerical analysis in order to evaluate mechanical stresses in the straight part of field coil by armature reaction on steady-state operation. The analytical results will be presented in this paper.

The stability and the protection of superconducting applications are very important issues. High temperature superconductor (HTS) is stable than low temperature superconductor (LTS). However, due to the high stability of HTS, HTS coils have complicate behaviors of normal transition – such as a recovery into the superconducting state or thermal runaway – which is determined by the magnitude of disturbance, coil size, the structure of winding wire and cooling condition. In this paper, we propose the quench protection system based on the active power method which can detect the quench by measuring the generating instantaneous active power in HTS coils. And the quench detection circuit adopted a software circuit by LabVIEW which was added a new quench protection technique to the circuit in order to improve its detection performance. Furthermore, it can monitor interior states of HTS coils with acquiring the only coil voltages in real time. To confirm the validity of the suggested technique, the experiments were performed with the hardware circuit for quench detection simultaneously. The experimental results are presented and discussed in this paper.

This paper presents the quench detection method with using normal transition behavior for HTS coil. If the HTS coil starts to propagate a normal zone by an initial quench, it will be recovered the superconducting state or runaway thermally. These behaviors were mainly determined by variety parameters like the magnitude of a disturbance, HTS coil size, the structure of winding wire and cooling condition. However, the first step of detection or protection for coils should be started from detecting the presence of a non-recovering normal zone. This paper classifies the initial quench behaviors of HTS wires or coils as a model of 3-type tendencies, and suggests suitable detection techniques for each tendency with using the end-to-end voltage of coil. In additional, this method is able to detect a quench without a decisive criterion used at other quench detection methods. In order to confirm the validity of the method, we used the HTS sample coil wound with YBCO tapes. This paper presents these results and the quench protection properties with fabricated detection method.

Recently, the superconducting devices using cryogenic and superconducting technologies were widespread in the field of electric power. The 2G wires with YBCO superconducting layer, metal substrate and stabilizer layer are expected to be used in future superconducting applications, because it has high Jc properties in high temperature and high magnetic fields. In order to operate safely at high transport currents, the thermal stability of the wounding wire should be addressed in terms of detection and protection against the quench. On the other hand, the understanding of the 3-dimensional normal zone expansion during a quench is very important to design the superconducting devices such as magnets and cables. This paper presents the results of an experimental study for normal zone propagation properties in the longitudinal and transverse directions using the pancake coil wound with 2G wires which have Cu and SUS stabilizers under the cryocooler cooling. And the minimum quench energy (MQE) of the pancake coils wound with two different kinds of stabilizers as functions of operating temperature and transport current will be described.

Recently, the superconducting devices using cryogenic and superconducting technologies were widespread in the field of electric powers. The quench protection is one of the important issues for safety operating of the superconducting devices, because the excessive joule heating brings about damage to the superconducting magnets when the quench occurs. However, if the HTS coil starts to transit normally by an initial quench, it will be recovered into the superconducting state or runaway thermally. These behaviors were mainly determined by the magnitude of a disturbance, HTS coil size, the structure of winding wire and cooling condition. Therefore, in order to detect the transition into the normal state at HTS coil more accurately, it needs to investigate these effects as parameters. This paper describes the electromagnetic and thermal behaviors of HTS during normal transition by the initial quench. The aim is the development of the quench detection method about HTS coil for 5 MW HTS motor after an initial quench. It adopted the hardware and the software that were able to estimate the quench by monitoring the voltage and temperature for the behavior between the thermal runaway and the recovery. This paper will be presented these results and the quench protection properties with fabricated detection method.

The resistive type fault current limiter based on YBCO thin film with high critical current density was proposed and developed because of its fast recovery characteristics. We have been developing a magnetic field measurement system with hall sensor to study the critical current density distribution or magnetic properties of high-Tc superconductors such as thin film, tape conductor and coated conductors. In this study, the transport current distribution in straight line and U-corner region of meander type resistive fault current limiter using YBCO thin film was investigated experimentally. The both axial and radial self-magnetic field components according to the direct (DC) and alternating (AC) transport currents were measured by two-axis hall probe to estimate the current distribution. And also, the self-magnetic field at the corner of bispiral type fault current limiter was measured by two-axis hall probe with a high spatial resolution to compare with the meander type fault current limiter.

We have been developing a 3D superconducting actuator with HTS (high temperature superconducting) bulk and two-dimensionally arranged multiple electromagnets. The application of HTS bulk enables stable levitation and suspension due to its strong pinning force. The performance of the actuator is determined mainly by the spatial distribution of the generated magnetic field of the electromagnets. For the sake of improving the levitation force, we proposed to attach a sliced iron sheet (we called this cap core) on the top surface of the core in each electromagnet. The proposed cap core was expected to lead to an intensive concentration and abrupt gradient increase of the perpendicular component in the magnetic field through the HTS bulk of the electromagnets. We experimentally confirmed and measured the effect of the cap core. For the optimized design of the cap core, we calculated the spatial distribution of the magnetic field on the surface of the electromagnet using 3D FEM analysis for several cap cores and estimated the levitation force of the HTS bulk using the calculated result.

We have been investigating a three-dimensional (3-D) superconducting actuator using HTS bulk to develop the transportation device with non-contact and move in free space. Proposed superconducting actuator consists of the stator constructed by two-dimensional arranged electromagnets and HTS bulk superconductor as a mover. The 2-D arranged electromagnets were individually controlled to move the HTS bulk. It is expected that our proposed 3-D superconducting actuator will be useful as a transporter used in clean rooms where silicon wafers are manufactured. Wafers must be protected from contact with dust and other contamination. To realize the superconducting actuator with HTS bulks, the electromagnetic characteristics of HTS bulk, such as trapped field strength and patterns, should be clarified and the optimized controlling system is also required. Therefore, in this study, to construct the optimal 3-D actuator system, the fundamental characteristics of the levitation for HTS bulks with individually controlled four and eight-polarities electromagnets were investigated experimentally. And two kinds of cap cores attached the top of the core to improve the control ability of proposed actuator were fabricated and tested.

The degree of ferromagnetism of Ni-Wy alloys decreases as W-content y increases. Both the saturation magnetization M sat and Curie temperature T c decrease linearly with W-content y, and both M sat and T c go to zero at critical concentration of yc ~9.50 at.% W. To compare with Ni-W alloys, the magnetic properties of a series of both as-rolled (non-textured) and annealed (biaxially textured) [Ni97at.%-W3at.%]100-x-Cux alloy tapes with compositions x = 0, 1, 3, 5, and 7 at.%, were studied. Characterization methods included XRD analyses to investigate the biaxial texturing of the annealed [Ni-W]-Cu alloy tapes and studies of the magnetization for both as-rolled and annealed [Ni-W]-Cu alloy tapes. Both the isothermal mass magnetizations M(H) of a series of samples at different fixed temperatures and M(T) in fixed field, were measured. The effect of Cu addition on both the saturation magnetization and Curie temperature Tc of the Ni97at.%-W3at.% alloy was investigated.

Many high temperature superconducting (HTS) tape manufactures make an effort to reduce the transport current loss of HTS tapes. The knowledge of critical current and self-field in an HTS tape is very useful to compute the transport current losses. The spatial distribution and magnitude of self-field are variable due to the neighboring materials. In this paper, the critical currents and the transport current losses of BSCCO and YBCO tapes with paralleled magnetic material (Ni tape) and/or diamagnetic material (BSCCO tape) are experimentally investigated to improve the AC loss properties. The critical currents of HTS tapes with paralleled Ni tape are slightly decreased and the transport current losses are markedly increased. However, the critical currents and transport current losses of HTS tapes with paralleled BSCCO tape have not current carrying are more improved than single HTS tape

After the discovery of HTS (High Temperature Superconductor), many types of HTS conductors have been developed. Several BSCCO tapes fabricated by PIT (Powder In Tube) method became commercially available, and the transport current loss characteristics of BSCCO tapes have been investigated by many research groups. The transport current loss characteristics of YBCO tapes, however, are not well studied. This is because measuring transport current requires tape samples over a certain length (15 cm for our own system). Many groups are currently focusing their effort on manufacturing long YBCO tape conductors, and new world records of length and current carrying capability are replacing the old ones in an increasingly fast rate. This paper deals with transport current losses of commercially available BSCCO tapes and YBCO tapes made at Korea Electrotechnology Research Institute (KERI) of Korea. YBCO tapes show relatively high transport current losses. This can be explained by the fact that the YBCO tape does not consist of filaments. Measurement results of the tapes are presented with analyses and discussions.

To investigate the effect of Ag or SiC nano-powder additions on the superconducting properties of MgB/sub 2/, a series of superconducting (Ag)/sub (x)wt.-%/(MgB/sub 2/)/sub (100-x)wt.-%/(Ag/sub x/-MgB/sub 2/) and (SiC)/sub (x)wt.-%/(MgB/sub 2/)/sub (100-x)wt.-%/((SiC)/sub x/-MgB/sub 2/)(0/spl les/x/spl les/20), containing Ag and SiC nano-powders, respectively, of different diameters (30 nm and 130 nm), were prepared by a simple solid-state reaction route, cold-pressed into a pellet form and investigated. To maintain the same environment of MgB/sub 2//stainless-steel tapes/wires, Ag/sub x/-MgB/sub 2/ and (SiC)/sub x/-MgB/sub 2/ pellets made out of the mixed powders were put inside stainless steel tubes and then sintered at 900/spl deg/C for two hours in Ar atmosphere. Characterization performed included both X-ray diffraction and magnetization. No impurity phase was identified for as-rolled samples. However, both the Ag/sub x/-MgB/sub 2/ and (SiC)/sub x/-MgB/sub 2/ composite pellets, when sintered, contain various impurity phases. The isothermal magnetizations M(H) of a series of samples were measured at temperatures between 5 and 50 K in fields up to 5 T, using a PPMS-9 (Quantum Design). The optimal amounts of Ag and SiC nano-powder in Ag/sub x/-MgB/sub 2/ and (SiC)/sub x/-MgB/sub 2/ to obtain the largest flux pinning effect are /spl sim/8 and /spl sim/4 wt.-%, respectively. The "two-step" structures in ZFC M(T) curves of (SiC)/sub x/-MgB/sub 2/ were more developed than Ag/sub x/-MgB/sub 2/. The best flux pinning centers can be created by adding a suitable size and amount of SiC nano-powder, not too large to increase the decoupling between the MgB/sub 2/ grains.

Single-, multi-, and two kinds of coaxial-filament composite MgB 2 /SS–SS (stainless steel for both outer and inner tubes) and MgB 2 /SS–Cu (stainless steel for outer tube and copper for inner tube) wires were successfully fabricated using powder-in-tube (PIT) process with swaging only. The effect of the geometries of the MgB 2 PIT wires has been studied comparatively. The isothermal magnetizations M ( H ) for both the sintered and the as-rolled single-, multi-, and coaxial-filament MgB 2 wires were measured at temperatures between 5 and 50 K in fields up to 5 T. The critical current density was estimated by the M ( H ) data using Bean model. The coaxial-filament composite MgB 2 wires showed much better J c than both the single- and the multi-filament composite ones. The results of this study show that the superconducting properties of the MgB 2 PIT wires/tapes can improve by employing better geometries such as the coaxial-filament composite MgB 2 /SS–SS wires.

Performance of an HTS (high temperature superconductor) tape is evaluated by measuring the critical current I/sub c/, AC loss and mechanical properties of the short samples. However, in coils or magnets for applications, the HTS tapes are under mechanical load caused by winding tension, bending and sometimes twisting. Also thermal contraction by the cooling changes the tension. The mechanical load reduces the critical current of the superconducting wire, and the I/sub c/ degradation affects the AC loss of the wire. We measured the I/sub c/ degradations and AC losses (transport current loss) of commercial Bi-2223 tapes processed by a PIT (powder in tube) method under tension. The I/sub c/ and AC loss measurements are done in the same time with the same voltage taps on the tape conductors. The measurement results and discussions on the relationship between I/sub c/ degradation and AC loss are presented.

It is known that external magnetic field not only causes the magnetization loss in a superconducting tape, but also increases the transport current loss, by the so-called "dynamic resistance". In power applications, superconductors carrying alternating current should be in alternating magnetic field. The frequency of the field is usually the same as that of the transport current, but they have phase difference. We developed an experimental system, which can measure transport current loss in external AC magnetic fields. With this equipment, we explored the effect of external field on the transport current loss with various field strengths and phase differences. This paper describes experimental results and discussions on the effect of amplitude and phase on transport current loss of HTS (high temperature superconductor) tape.

A high temperature superconductor (HTS) power transmission cable is usually made of several layers of helically wound superconductor tapes. The current distribution among the conductor tapes is controlled mainly by pitches and winding directions of the layers, because the inductance of the layer is determined by the pitch and the winding direction. Two winding directions––right and left––are possible for each layer, and we can list up many possible combinations of winding directions. If we choose a good combination we can find the optimal pitches and make an even current distribution. However, with a bad combination of the winding direction, it is almost impossible to find a solution. We developed a software code to calculate the currents of the layers. With this software we studied the effect of the winding direction on a four-layer cable by a statistical way. A brief description of the software, calculation results and discussions will be presented.

A study was conducted to evaluate seasonal variations in chemical composition of food waste (FW) and its feeding effects on growth performance and pork quality in finishing pigs. FW was collected for 1 year (6 times a month) to establish a database for use of FW as a feed ingredient. For a feeding trial (8 weeks), a total of 117 pigs (L×Y×D; 54.80±4.60kg) were used to evaluate the processing effects of FW. Treatments were: Control (a corn-soybean meal diet without FW), simple dried FW (SD) and vacuum fermented FW (VF). The gross energy, crude protein, crude fat, ash, calcium and phosphorus in FW (DM, average of 4 seasons) were 5,111kcal/kg, 22.92%, 14.31%, 15.48%, 2.7% and 1.05%, respectively. Among seasons, the energy and crude protein contents were the highest (p

We have been developing a new type of 3-D superconducting actuator using the strong pinning force of HTS (high temperature superconducting) bulk. The system includes HTS bulk and two-dimensionally arranged multiple electromagnets. The application of HTS bulk enables stable levitation and suspension, and its performance is determined mainly by the spatial distribution of the generated magnetic field of the electromagnets. To enhance the levitation force in the actuator, it is necessary to design the optimized geometry of the electromagnets. The target of the design is to lead to an intensive concentration and abrupt gradient increase of the perpendicular component in the magnetic field through the HTS bulk over the electromagnets. For the optimized design of the electromagnets, we calculated the spatial distribution of the trapped magnetic field and the levitation force of the HTS bulk using 3-D FEM analysis that is adopted the critical state model.

Summary form only given, as follows. Flat panel display (LCD, PDP, OLED) requires high quality thin film layer (ITO, SiO/sub x/, MgO) deposition at low substrate temperature. To enhance film adhesion and composition in reactive magnetron sputtering, additional energy source is necessary to dissociate the reactive gas molecules and to ionize the depositing particles for easier energy control.

In designing and manufacturing of a new type of compact nuclear magnetic resonance/magnetic resonance imaging magnet, which consists of a stacked high-temperature superconducting (HTS) bulk annuli, the spatial homogeneity and the temporal stability of the trapped magnetic fields are the key issues. On the other hand, there is an asymmetry problem for superconducting properties including the critical current density along the axial (thickness) direction in HTS bulks due to its manufacturing process using a seed crystal located at the top surface. Therefore, in this study, we find the nonuniformity of the critical current density of the HTS bulk along the axial direction, which probably comes from the quench-melt-growth process using a seed crystal. The measured axial positions of the maximum magnetic field were slightly shifted to the bottom direction lower than the axial center position. The critical current density and/or superconducting properties of HTS bulks are probably decreased in proportion to the distance from a seed crystal. Therefore, the superconducting properties along the thickness direction in the HTS bulk were represented as a variable Jc - B and electrical conductivity.

A new type of microwave amplifier module, consisting of a solid-state amplifier, a predistortion linearizer, and a traveling-wave-tube (TWT), is realized. Measurements show a noise figure of 2.2 dB at 9.5 GHz and the third-order intermodulation distortion ratio of 53 dBc at 10 dB back off from P1 dB point.

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The electric device applications of a high temperature superconducting (HTS) bulk magnet, having stable levitation and suspension properties according to their strong flux pinning force, have been proposed and developed. We have been investigating a three-dimensional (3-D) superconducting actuator using HTS bulks to develop a non-contact transportation device which moves freely in space. In our previous work, the unstable movement characteristics of HTS bulk were observed under DC operation, and the AC control system was proposed in order to solve these problems. In this paper, the horizontal movement and the field decay characteristics as a function of the gap length between electromagnet and HTS bulk and the frequency of driving current were investigated experimentally.

In the case of motors and generators, the benefits of using superconductors could be represented by the reduction of 50% in both losses and sizes compared to the conventional machines of the same rating. The high temperature superconducting (HTS) coils wound with HTS conductors have very low normal zone propagation velocity (NZPV) and complicated quench behaviors because the conductors have a low thermal conductivity and large specific heat. According to these reasons, in case of HTS coils and magnets, it is difficult to expect the self-protection like as low temperature superconducting (LTS) coils. In this paper, we suggest a method which inserts the Cu tape between turn-turn winding in the HTS coil instead of electrical insulation to improve the self-protection ability of HTS coils. Because the thermal and electrical contacts along the transverse direction are enhanced by inserted Cu tape instead of insulator and the whole thermal stability of HTS coils would be increased. To clarify the quench behavior of this suggested coil, we investigate the normal-zone propagation properties of the fabricated HTS pancake coils wound with 2G conductor and Cu tape under the cryocooled operation using GM cryocooler. The effects of inserted Cu tape and the improved the self-protection ability for the suggested HTS coil will be discussed.

TiN was deposited onto phosphorus bronze, single-crystal NaCl and p-Si(100) by biased activated reactive evaporation (BARE). The influence of the plasma conditions during deposition on the preferred orientation and resistivity of the TiN film were investigated using an electrostatic plasma probe. The electron temperature and electron density were measured at various substrate biases and activated reactive evaporation (ARE) discharge currents. Films deposited at a negative bias, and consequently at a high electron temperature, showed strong (200) preferred orientation, low electrical resistivity and high hardness. In contrast, a high ARE discharge current, and hence a high electron density, led to enhanced (111) texture and higher resistivity. The cause of the (200) preferred orientation at a high negative bias is considered to be that titanium ions of upper critical energy can bombard the growing film surface and transform the (111) texture into the (200) preferred orientation by deep impact insertion of nitrogen between titanium atoms.