| 单词 | 半衰期 |
| 释义 | 〔hassium〕An artificially produced radioactive element with atomic number 108 whose most long-lived isotopes have mass numbers of 264 and 265 with half-lives of 0.08 milliseconds and 2 milliseconds, respectively. Also called unniloctium ：人造放射性元素，原子序数号为108，生命期最长同位素的质量为264和265，半衰期分别为0.08毫秒和2毫秒 也作 unniloctium〔plutonium〕A naturally radioactive, silvery, metallic transuranic element, occurring in uranium ores and produced artificially by neutron bombardment of uranium. Its longest-lived isotope is Pu 244 with a half-life of 76 million years. It is a radiological poison, specifically absorbed by bone marrow, and is used, especially the highly fissionable isotope Pu 239, as a reactor fuel and in nuclear weapons. Atomic number 94; melting point 640°C; boiling point 3,235°C; specific gravity 19.84; valence 3, 4, 5, 6. See table at element 钚：一种天然地放射性银色超铀金属元素，存在于铀矿中，对铀元素进行中子轰击而人工制成。其存在周期最长的同位素是半衰期为七千六百万年的钸244，它是一种核辐射毒素，特别是能被骨髓吸收。尤其是其极具可裂变性的同位素钸239，被用作一种核反应燃料并用在核武器中。原子序数94；熔点640°C；沸点3,235°C；比重19.84；化合价3, 4, 5, 6 参见 element〔astatine〕A highly unstable radioactive element, the heaviest of the halogen series, that resembles iodine in solution. Its longest lived isotope has a mass number of 210 and has a half-life of 8.3 hours. Atomic number 85; melting point 302°C; boiling point 337°C; valence probably 1, 3, 5, 7. See table at element 砹：极不稳定放射性元素，在卤族元素比重最大，在溶解状态与碘相象，它最长周期的同位素原子量为210，半衰期为8.3小时。原子序数85；溶点302°C；沸点337°C；化合价可能为1、3、5、7 参见 element〔technetium〕A silvery-gray radioactive metal, the first synthetically produced element, having 14 isotopes with masses ranging from 92 to 105 and half-lives up to 2.6×106 years. It is used as a tracer and to eliminate corrosion in steel. Atomic number 43; melting point 2,200°C; specific gravity 11.50; valence 0, 2, 4, 5, 6, 7. See table at element 锝：一种银灰色放射性金属，是第一个人工合成的元素，有十四个原子量从92到105且半衰期高达2.6×106年的同位素。用作放射追踪剂并可消除钢铁腐蚀现象。原子序数43；熔点2,200°C；比重11.50；原子价0, 2, 4, 5, 6, 7 参见 element〔dubnium〕An artificially produced radioactive element with atomic number 105 whose most long-lived isotopes have mass numbers of 258, 261, 262, and 263 with half-lives of 4.2, 1.8. 34, and 30 seconds, respectively. Also called unnilpentium ：人造放射性元素，原子序数号为105，生命期最长同位素的质量为258、261、262和263，半衰期分别为4.2秒、1.8秒、34秒和30秒 也作 unnilpentium〔americium〕A white metallic transuranic element of the actinide series, having isotopes with mass numbers from 237 to 246 and half-lives from 25 minutes to 7,950 years. Its longest-lived isotopes, Am 241 and Am 243, are alpha-ray emitters used as radiation sources in research. Atomic number 95; specific gravity 11.7; valence 3, 4, 5, 6. See table at element 镅：锕系元素中的一种白色超铀金属元素，其同位素原子序数是从237到246，半衰期从25分钟到7,950年。其寿命最长的同位素镅241和镅243在研究中用作α射线辐射源。原子序数为95；比重11.7；原子价为3,4,5,6 参见 element〔actinon〕A radioactive, inert, gaseous isotope of radon, with a half-life of 3.92 seconds.锕射气：氡的一种放射性的，惰性的和气态的同位素，其半衰期为3.92秒〔actinium〕A radioactive element found in uranium ores, used in equilibrium with its decay products as a source of alpha rays. Its longest lived isotope is Ac 227 with a half-life of 21.7 years. Atomic number 89; melting point 1,050°C; boiling point (estimated) 3,200°C; specific gravity (calculated) 10.07; valence 3. See table at element 锕：一种在铀矿中发现的放射性元素，作为阿尔法射线能源增入点用于与其衰变产物的平衡过程中，其最长的活同位素是半衰期为21.7年的锕227。原子序数为89；熔点为1,050摄氏度；（估计的）沸点为3,200摄氏度；（计算出的）比重为10.07；原子价为3 参见 element〔polonium〕A naturally radioactive metallic element, occurring in minute quantities as a product of radium disintegration and produced by bombarding bismuth or lead with neutrons. It has 27 isotopes ranging in mass number from 192 to 218, of which Po 210, with a half-life of 138.39 days, is the most readily available. Atomic number 84; melting point 254°C; boiling point 962°C; specific gravity 9.32; valence 2, 4. See table at element 钋：一种具有天然辐射性的金属元素，作为镭分裂的产物以极小量出现，可通过用中子轰击铋或铅获得。它从192到218的质量数中可排列为27种同位素，其中的钋210半衰期达138.39天，是最易得到的同位素。原子序数84；熔点254°C；沸点962°C；比重9.32；化合价2, 4 参见 element〔nobelium〕A radioactive transuranic element in the actinide series, artificially produced in trace amounts. Its longest-lived isotope is No 255 with a half-life of 3 minutes. Atomic number 102. See table at element 锘：在锕类元素中的一种放射性超铀元素，人工微量制造，其最长寿命的同位素是锘255，其半衰期为三分钟，原子序数102 参见 element〔radium〕A rare, brilliant white, luminescent, highly radioactive metallic element found in very small amounts in uranium ores, having 13 isotopes with mass numbers between 213 and 230, of which radium 226 with a half-life of 1,622 years is the most common. It is used in cancer radiotherapy, as a neutron source for some research purposes, and as a constituent of luminescent paints. Atomic number 88; melting point 700°C; boiling point 1,737°C; valence 2. See table at element 镭：一种稀有的、有白色光泽、发光、高度放射性的金属元素，极少量地存在于沥青矿中，有13种同位素，质量数介于213和230之间，最常见的为镭226，半衰期为1,622年。镭可用于癌症的放射治疗，在其它一些研究中用作中子源，还可用作发光颜料的成分。原子序数88；熔点700°C；沸点1,737°C；原子价2 参见 element〔neptunium〕A silvery, metallic, naturally radioactive element, atomic number 93, the first of the transuranium elements. Its longest-lived isotope is Np-237 with a half-life of 2.1 million years. Found in trace quantities in uranium ores, it is produced synthetically by nuclear reactions. See table at element 镎：一种银白色的、金属性天然放射性元素，原子序数为93，第一个超铀元素。其周期最长的同位素为Np-237，半衰期为210万年。见于铀矿的示踪量中，由核反应合成生产出来 参见 element〔fermium〕A synthetic transuranic metallic element (atomic number 100) having 10 isotopes with mass numbers ranging from 248 to 257 and corresponding half-lives ranging from 0.6 minute to approximately 100 days. See table at element 镄：一种人工产生的放射性金属元素（原子序数为100），拥有10个在元素周期表中从248到257的同位素，半衰期从0.6分钟到约100天 参见 element〔francium〕An extremely unstable radioactive element of the alkali metals, produced artificially from actinum or thorium, having approximately 19 isotopes, the most stable of which is Fr 223 with a half-life of 21 minutes. Atomic number 87; valence 1. See table at element 钫：从碱金属锕或钍中人工提炼出的一种极不稳定的放射线元素，约有19种同位素，其中最稳定的是半衰期为21分钟的Fr223。原子序数为87；化合价为1 参见 element〔radon〕A colorless, radioactive, inert gaseous element formed by the radioactive decay of radium. It is used as a radiation source in radiotherapy and to produce neutrons for research. Its most stable isotope is Rn 222 with a half-life of 3.82 days. Atomic number 86; melting point -71°C; boiling point -61.8°C; specific gravity (solid) 4. See table at element 氡：一种无色、有放射性的惰性气体元素，由镭蜕变产生。在放射疗法中可用作辐射源，在科研中可用于制造中子。它最稳定的同位素是Rn222。半衰期为3.82天。原子序数86；熔点-71°C；沸点-61.8°C；比重（固态）4 参见 element〔curium〕A silvery, metallic synthetic radioactive transuranic element. Its longest lived isotope is Cm 247 with a half-life of 16.4 million years. Atomic number 96; melting point (estimated) 1,350°C; valence 3. See table at element 锔：一种合成的银色放射性超铀金属元素。其周期最长的同位素是Cm247，该同位素的半衰期为16.4百万年。原子序数96；熔点（估计值）1,350°C；三价 参见 element〔thoron〕A radioactive isotope of radon, Rn 220, having a half-life of 54.5 seconds and produced by the disintegration of thorium.钍射气：一种由钍的裂解产生的Rn220的放射性同位素，半衰期为54.5秒〔einsteinium〕A synthetic transuranic element first produced by neutron irradiation of uranium in a thermonuclear explosion and now usually produced in the laboratory by irradiating plutonium and other elements. Its longest-lived isotope is Es 254 with a half-life of 276 days. Atomic number 99; melting point 860°C. See table at element 锿：一种人工合成超铀元素，在一次热核子反应的铀中子辐射中首次产生。 现在通常通过在实验室里辐照钚和其它元素而产生，其最不易衰变的同位素是Es254， 它的半衰期为276天，原子序数99；熔点860°C 参见 element〔mendelevium〕A synthetic radioactive transuranium element of the actinide series. Atomic number 101; mass numbers 255 and 256; half-lives approximately 30 minutes (Md 255) and 1.5 hours (Md 256). See table at element 钔：锕系之合成放射性超铀元素。其原子序数为101；质量数为255和256；半衰期大约为30分钟（质量数为255的元素），及一个半小时（质量数为256的元素） 参见 element〔californium〕A synthetic element produced in trace quantities by helium isotope bombardment of curium. All isotopes are radioactive, chiefly by emission of alpha particles. Atomic number 98; mass numbers 244 to 254; half-lives varying from 25 minutes to 800 years. See table at element 锎：一种合成元素，由氦同位素轰击锔可得到微量的这种元素。所有同位素均是放射性元素，主要放射出α粒子。原子序数98；原子量244到254；半衰期从25分钟到800年不等 参见 element〔berkelium〕A synthetic transuranic radioactive element having 9 isotopes with mass numbers from 243 to 250 and half-lives from 3 hours to 1,380 years. Atomic number 97; melting point 986°C; valence 3, 4. See table at element 锫：一种人造的铀后放射元素，有9个大数字的同位素，从243到250，半衰期从3小时到1,380年。原子序数为97；熔点986°C；原子价3，4 参见 element〔tritium〕A rare radioactive hydrogen isotope with atomic mass 3 and half-life 12.5 years, prepared artificially for use as a tracer and as a constituent of hydrogen bombs.氘：氢的放射性稀有同位素，原子量为3，半衰期12.5年，人工配制可用作指示剂和氢弹的组成部分〔bohrium〕An artificially produced radioactive element with atomic number 107 whose most long-lived isotopes have mass numbers of 261, 262, and 264 with half-lives of 11.8 milliseconds, 0.1 seconds, and 0.44 seconds, respectively. Also called unnilseptium ：人工产生的放射性元素，原子序数号为107，生命期最长同位素的质量为261、262和264，半衰期分别为11.8毫秒、0.1秒和0.44秒 也作 unnilseptium〔thorium〕A radioactive silvery-white metallic element that is recovered commercially from monazite. Its longest-lived isotope, the only one that occurs naturally, is Th 232 with a half-life of 1.41 × 1010 years. It is used in magnesium alloys, and isotope 232 is a source of nuclear energy. Atomic number 90; atomic weight 232.038; approximate melting point 1,750°C; approximate boiling point 4,500°C; approximate specific gravity 11.7; valence 4. See table at element 钍：一种商业上从独居石中提取的放射性银白色金属元素，其自然界中寿命最长的同位素是钍232，半衰期为141×1010年。用于镁合金，同位素232是核能的来源。原子序数90；原子量232.038；熔点约为1,750°C；沸点约为4,500°C；比重约为11.7；原子价为4 参见 element〔protactinium〕A rare, extremely toxic, radioactive element chemically similar to uranium, having 13 known isotopes, the most common of which is protactinium 231 with a half-life of 32,480 years. Atomic number 91; melting point 1,230°C; specific gravity 15.37; valence 4, 5. See table at element 镤：一种稀有的、剧毒放射性元素，在化学性质上与铀相似。有十三个已知的同位素，其中最常见的是半衰期为32,480年的镤231。原子序数为91；熔点1,230°C；比重15.37；原子价4, 5 参见 element〔lawrencium〕A short-lived, radioactive synthetic transuranic element produced from californium and having isotopes with mass numbers 255 through 260 and half-lives of a few seconds to three minutes; atomic number 103. See table at element 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103 参见 element〔seaborgium〕An artificially produced radioactive element with atomic number 106 whose most long-lived isotopes have mass numbers 259, 261, 263, 265, and 266 with half-lives of 0.9, 0.23, 0.8, 16, and 20 seconds, respectively. Also called unnilhexium ：人工产生的放射性元素，原子序数号为106，生命期最长同位素的质量为259、261、263、265和266，半衰期分别为0.9秒、0.23秒、0.8秒、16秒和20秒 也作 unnilhexium〔meitnerium〕An artificially produced radioactive element with atomic number 109 whose most long-lived isotopes have mass numbers of 266 and 268 with half-lives of 3.4 milliseconds and 70 milliseconds, respectively. Also called unnilennium ：人工产生的放射性元素，原子序数号为109，生命期最长同位素的质量为266和268，半衰期分别为3.4毫秒和70毫秒 也作 unnilennium |
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