أرسل هذا في رسالة قصيرة: Theory of phase transitions in second-order ferroelectric films: effects of surfaces and surface-induced stresses on polarization

導出完成 — 

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