發送短信 : Air-coupled nonlinear ultrasonic test for reinforced concrete beams

 ______      ___    __    __    ______    ____    
|      \\   / _ \\  \ \\ / //  /_   _//  |  _ \\  
|  --  //  | / \ ||  \ \/ //    -| ||-   | |_| || 
|  --  \\  | \_/ ||   \  //     _| ||_   | .  //  
|______//   \___//     \//     /_____//  |_|\_\\  
`------`    `---`       `      `-----`   `-` --`