half life

简明释义

半裹期

英英释义

例句

1.Understanding the half life of carbon-14 is crucial for accurate dating in archaeology.

了解碳-14的半衰期对考古学中的准确测年至关重要。

2.The radioactive isotope has a half life of 5 years, meaning it takes that long for half of it to decay.

这个放射性同位素的半衰期为5年，这意味着需要那么长时间才能使一半的同位素衰变。

3.In pharmacology, the half life of a drug determines how often it needs to be administered.

在药理学中，药物的半衰期决定了它需要多频繁地给药。

4.After 10 half lives, a radioactive substance is considered safe to handle.

经过10个半衰期后，放射性物质被认为是安全的。

5.The half life of caffeine in the human body is about 3 to 5 hours.

咖啡因在人体内的半衰期约为3到5小时。

作文

The concept of half life is a fundamental principle in various scientific fields, particularly in chemistry and physics. It refers to the time required for half of the quantity of a radioactive substance to decay or transform into another element. This principle not only applies to radioactive isotopes but also to other processes such as pharmacokinetics, where it describes the time taken for the concentration of a drug in the bloodstream to reduce by half. Understanding half life is crucial for scientists and medical professionals alike, as it helps them predict how long a substance will remain active or effective in a given environment.In nuclear physics, the half life of an isotope indicates its stability and the rate at which it undergoes radioactive decay. For instance, Uranium-238 has a half life of about 4.5 billion years, making it relatively stable, while Carbon-14, used in radiocarbon dating, has a half life of approximately 5,730 years. This difference in half life allows scientists to date ancient organic materials and understand the timeline of historical events.In the realm of medicine, the half life of drugs is essential for determining dosing schedules. For example, if a medication has a half life of 4 hours, this means that after 4 hours, half of the drug's concentration in the bloodstream will have decreased. This information is vital for healthcare providers to ensure that patients receive the correct dosage at appropriate intervals to maintain therapeutic levels of the medication without causing toxicity.Moreover, the concept of half life can be applied to environmental science, particularly in understanding the persistence of pollutants in ecosystems. For example, if a chemical contaminant has a half life of 10 years in soil, it implies that after 10 years, half of the initial amount of the contaminant will still be present, affecting the surrounding flora and fauna. This knowledge assists in developing strategies for pollution management and remediation efforts.In conclusion, the term half life encapsulates a critical aspect of decay and transformation across various disciplines. Whether in the context of radioactive isotopes, drug metabolism, or environmental contaminants, understanding half life provides valuable insights into the behavior and longevity of substances. This knowledge is not only academically significant but also has practical implications in fields such as medicine, environmental science, and even archaeology. As we continue to explore the intricacies of our world, the concept of half life remains a key tool in deciphering the mysteries of time and change.

“半衰期”这一概念是多个科学领域的基本原理，尤其是在化学和物理学中。它指的是一种放射性物质衰变或转化为另一种元素所需的时间。在放射性同位素的研究中，这一原理不仅适用于放射性同位素，还适用于其他过程，如药物代谢动力学，其中它描述了血液中药物浓度降低一半所需的时间。理解“半衰期”对科学家和医疗专业人士至关重要，因为它帮助他们预测某种物质在特定环境中保持活性或有效的时间。在核物理学中，放射性同位素的“半衰期”表明其稳定性以及其进行放射性衰变的速率。例如，铀-238的“半衰期”约为45亿年，这使得它相对稳定，而用于放射性碳定年的碳-14的“半衰期”大约为5730年。这种“半衰期”的差异使科学家能够对古代有机材料进行定年，并理解历史事件的时间线。在医学领域，药物的“半衰期”对于确定给药时间表至关重要。例如，如果一种药物的“半衰期”为4小时，这意味着在4小时后，药物在血液中的浓度将减少一半。这些信息对于医疗提供者确保患者在适当的间隔内获得正确剂量，以维持药物的治疗水平而不导致毒性反应至关重要。此外，“半衰期”的概念也可以应用于环境科学，特别是在理解污染物在生态系统中的持久性方面。例如，如果一种化学污染物在土壤中的“半衰期”为10年，这意味着在10年后，初始污染物的一半仍然存在，从而影响周围的植物和动物。这些知识有助于制定污染管理和修复工作的策略。总之，“半衰期”这一术语概括了各个学科中衰变和转化的关键方面。无论是在放射性同位素、药物代谢还是环境污染物的背景下，理解“半衰期”都能提供有关物质行为和持久性的宝贵见解。这些知识不仅在学术上具有重要意义，而且在医学、环境科学甚至考古学等领域也具有实际应用价值。随着我们继续探索世界的复杂性，“半衰期”的概念仍然是解开时间和变化之谜的关键工具。