文章大意：本文是一篇说明文。文章介绍的是中国东南大学的科学家们在材料科学上取得了突破，其研发出的压电材料不仅效果显著，而且可生物降解。这项研究代表了医疗植入物领域的重大进展。
4 . A new breakthrough in material science could revolutionize medical implants. Scientists at Southeast University in China have developed a piezoelectric material that is not only highly effective but also biodegradable. This innovation surpasses previous biodegradable options by a factor of 13 in terms of piezoelectric performance.
Piezoelectric materials have the unique ability to convert mechanical energy into electrical energy. This property makes them ideal for various medical implants, like pacemakers and drug delivery devices. However, traditional options lack biodegradability, necessitating a second surgery for removal after serving their purpose. This additional procedure can be expensive and carries inherent surgical risks.
The newly developed material, the discovery of which was led by Zhang Hanyue and Professor Xiong Rengen, is a kind of ferroelectric molecular crystal. The crystal offers the remarkable combination of both piezoelectricity and biodegradability. Notably, the material boasts a piezoelectric coefficient (d33) of approximately 138 picocoulombs per newton, a significant 13-fold increase compared to previous biodegradable materials.
Furthermore, the material is conveniently combined with polyvinyl alcohol (PVA), granting it high flexibility and biocompatibility within the body. This translates to safe implantation that can eventually dissolve naturally, eliminating the need for removal surgery.
The researchers envision this innovative material being utilized in a diverse range of next-generation medical implants. This research, published in the March 29 issue of Science magazine, represents a significant leap forward in the field of medical implants. Media outlets in China called the discovery a landmark breakthrough since the discovery of the piezoelectric effect by the Curie brothers in 1880.
1. What makes piezoelectric materials suitable for medical implants?
| A．Their ability to convert electrical energy into mechanical energy. |
| B．Their biodegradability after serving their purpose. |
| C．Their unique ability to convert mechanical energy into electrical energy. |
| D．Their low cost and ease of availability. |
2. The piezoelectric material is significant because it _____.
| A．increases the piezoelectric coefficient by 13 times |
| B．is only suitable for pacemakers |
| C．requires a second surgery for removal |
| D．lacks flexibility and biocompatibility |
3. The new material is combined with polyvinyl alcohol (PVA) to _____.
| A．improve its piezoelectric performance |
| B．make it biodegradable |
| C．enhance its flexibility and biocompatibility |
| D．reduce its cost of production |
4. Why it is considered a landmark breakthrough?
| A．It was the first piezoelectric material to be developed |
| B．It surpasses previous biodegradable options significantly |
| C．It was discovered by Chinese scientists |
| D．It has been mentioned in Science magazine |
