Preparation of TB(S)CCO Superconductor Coating by Electrophoretic Deposition Method

Abstract

The preparation of Tl2Ba2Ca2Cu3O10+ x (TBCCO) superconducting oxide coating on Ag wire by the electrophoretic deposition method was investigated. Because it was the TBCCO powder is chemically stable in cyclohexanone, and a cyclohexanone bath (20 m l cyclohexanone+2.0 mg iodine+0.4 g TBCCO powder) was used. The deposited sample dried by hot air was sintered at 785° C for 10 min in Tl atmosphere, and T c,zero was 104 K. The superconductivity of the Tl2Ba1.6Sr0.4Ca2Cu3O10+ x (TBSCCO) coating was improved if the deposited sample was completely covered with a large quantity of TBSCCO powder to control the evaporation of Tl from the sample. When the sample was sintered at 815° C for 6 h, a uniform and approximately single high-T c phase coating was obtained with a T c,zero of 113 K.

Negative Refraction and Energy-Transmission Efficiency of Acoustic Waves in Two-Dimensional Phononic Crystal: Numerical and Experimental Study

“…4) The negative group velocity of an essentially one-dimensional wave has been observed in the Lamb wave excited in multilayered structures. 5,6) Negative refraction results in a ''lens effect'' without convex or parabolic shape. In other words, a flat acoustic lens can be designed using phononic crystals.…”

Propagation Properties of Backward Lamb Waves in Plate Investigated by Dynamic Photoelastic Technique *

“…[11,12] In 1996, Negishi and Li visualized the third-order anti-symmetric backward mode (A 3b ) excited by an ultrasonic pulse in water obliquely striking the glass plate using photoelastic technique, and claimed that the wavelength of S 2b mode will become too large to be observed. [13] However, according to our numerical calculation and experimental results, it can be demonstrated that the leakage of acoustic energy for S 2b mode is more rapid than that of A 3b mode when the plate is immersed in water. As a result, S 2b mode can only be detected during a very short time.…”

“…It can be obtained that the main reason for the failure to visualize S 2b mode in Ref. [13] is the energy leakage instead of large wavelength. To explore the propagation characteristics of backward waves in detail, the plate was placed in air to avoid energy leakage in the following experiments.…”

“…Let us clarify the confusion in Ref. [13] firstly. Figure 2 shows the normalized attenuation of S 2b and A 3b modes caused by the leakage when the plate is placed in water and air.…”

Negative Group Velocities of Lamb-Type Waves in a Glass/Water/Glass Structure Controlled by the Thickness of Water Layer

“…Moreover, the negative group velocities appear near cut-off frequencies of particular propagation modes. 9) The range of the existing negative group velocities was found to depend on Poisson's ratio. 10) Indeed, the propagation characteristics of Lamb waves depend on the parameters of each material; therefore, the controllable range of the negative group velocities of the Lamb waves is quite limited.…”