一种放射性元素

People through nuclear reactions, have been synthesized 17 kinds of atomic number greater than 92 of the transuranic elements, and thousands of The new kinds of radioactive nuclides, and by high-energy and ultra-high energy-ray beam and the interaction of atomic nuclei and found hundreds of kinds of short-lived particles, namely, baryon, meson, lepton, and particle resonance states of these particles has led to a new field of study - the birth of particle physics since the age of .70, nuclear physics has entered a deep development and wide application of new, more mature stage, on the one hand the development of particle acceleration and detection techniques, expanding people's research in nuclear means, the other hand, nuclear technology to serve the national economy, for example, for the development and utilization of nuclear energy to provide more accurate nuclear data; the use of isotope tracer technique diagnosis and treatment of disease; the use of radiation and irradiation preservation of food, irradiation breeding .

人们通过核反应，已经人工合成了17种原子序数大于92的超铀元素和上千种新的放射性核素，并且通过高能和超高能射线束和原子核的相互作用，发现了上百种短寿命粒子、即重子、介子、轻子和共振态粒子，对这些粒子的研究导致了一门新学科——粒子物理学的诞生。70年代以来，核物理进入了纵深发展和广泛应用的新的更成熟的阶段，一方面发展粒子的加速技术和探测技术，扩充人们研究原子核的手段，另一方面将核技术服务于国民经济中，例如，为核能的开发利用提供更为准确的核数据；利用同位素示踪技术诊断和治疗疾病；利用射线及辐照技术保存食品、辐照育种等。

A radioactive transuranic element which has been synthesized.

一种合成的放射性超铀元素。

A short - lived , radioactive synthetic transuranic element produced from californium and having

铹一种寿命期短的、人工合成的放射性超铀元素，从锎中生成，有质量从255到260的同位素，半衰期从几秒钟到三分钟；原子序数

Ca is widely abundant in nature and its rodioisotope 41 Ca is a cosmogenic nuclide with a half\|life of 10 5 years. However, the 41 Ca/ 40 Ca ratio in natural samples is very low and can only be measure d by accelerator mass spectrometry. The application of 41 Ca is ve ry i mportant not only in the life science but also in geological dating, global envi ronment change studies and astrophysics.

1 引言Ca在自然界中广泛存在，它不仅是人体中含量最丰富的元素之一[1] ，也是众多其他物质的组成部分。41Ca(半衰期为 1.0 3× 10 5a)属于Ca的放射性同位素中的一种，其衰变方式为轨道电子俘获，只发射3.3keV的X射线，天然样品中41Ca 40 Ca的值很小。

What are your goals and strategies for growth?

你的成长目标和策略是什么？

And unto the angel of the church in Sardis write; These things saith he that hath the seven irits of God, and the seven star I know thy works, that thou hast a name that thou livest, and art dead.

3：1 你要写信给撒狄教会的使者，说，那有神的七灵和七星的，说，我知道你的行为，按名你是活的，其实是死的。