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本报告公布~(14)C地质年代数据43个,系本实验室1976年至1979年5月所测定。同时期内测定的考古样品年代数据已分四批在《文物》发表。报告中木头、木炭样品的化学处理同本实验室报告(一)。贝壳等碳酸盐样品用磷酸酸解制备CO_2。泥炭、淤泥和骨头等样品经预处理后,在管炉中通氧气燃烧制备CO_2,并使燃烧气流通过400℃载铂硅铝球催化剂(0.1%Pt/SiO_2-Al_2O_3),以保证样品的完全燃烧。CO_2合成碳化钙的装置和流程与Barker合成碳化锂法相似,但以金属钙代替金属锂。将掺有少量镁粉的细粒金属钙装入不锈钢反应器中(12升CO_2气体,约用80克钙、15克镁),抽真空,再加热到700℃左右,通入经纯化的CO_2气体。一般情况下12升CO_2可在几分钟
This report published ~ (14) C geochronology data 43, the Department of our laboratory from 1976 to May 1979 measured. In the meantime, the data of the archeological samples dating back to the previous period have been published in “Heritage” in four batches. Report in the wood, charcoal samples of the chemical treatment with the laboratory report (a). Carbonate samples such as shells were prepared by acid hydrolysis of phosphoric acid. After the pretreatment of peat, sludge and bones, CO 2 was produced through combustion of oxygen in a tube furnace, and the combustion gas flow was passed through a Pt-SiAl 2 O 4 catalyst (0.1% Pt / SiO 2 -Al 2 O 3) at 400 ℃ to ensure the completeness of the sample combustion. The device and process of CO 2 synthesis of calcium carbide are similar to the Barker method of synthesizing lithium carbide, except that metallic calcium replaces metallic lithium. A small amount of magnesium powder mixed with a small amount of calcium metal into a stainless steel reactor (12 liters of CO 2 gas, about 80 g of calcium, 15 g of magnesium), evacuated and reheated to about 700 ℃, the purified CO 2 gas. Under normal circumstances 12 liters CO_2 can be a few minutes