Nghĩa của từ radiocarbon bằng Tiếng Anh
Some of these neutrons react with nitrogen atoms in air, converting them into a radioactive isotope of carbon: carbon - 14 or radiocarbon , with eight neutrons in each nucleus.
Đặt câu với từ "radiocarbon"
1. 5 To correct this error radiocarbon dates are calibrated by studying the difference between radiocarbon dates and tree-ring dates.
2. Radiocarbon dating of the bones at Oxford University's Radiocarbon Accelerator Unit determined the time period to be 850 CE ±30 years.
3. They have supplied such samples to the radiocarbon laboratories, and these dates are now widely accepted as providing a solid foundation for the radiocarbon chronology.
4. 28 The journal Radiocarbon publishes the most up-to-date curves which in principle permit the conversion of radiocarbon dates to calibrated dates.
5. The title implies that radiocarbon dating is no longer regarded as absolute.
6. THE title of the Twelfth Nobel Symposium was “Radiocarbon Variations and Absolute Chronology.”
7. 13 Although calibration complicates the process of interpreting the radiocarbon results, it is essential.
8. 6 For the later range of radiocarbon dates this calibration is well-established.
9. 17 Thus, whenever possible the radiocarbon age should be calibrated to actual calendar years.
10. Arctogaean and postgrad students who need radiocarbon dating was founded in miami, provides fast high-quality ams dates
11. H03 Scientific Dates/ Radiocarbon Data* Indicate absolute dates acquired from the site or site components, if available.
12. (11) Buried samples can either gain or lose radiocarbon through leaching by groundwater or by contamination.
13. 23 In converting radiocarbon results to calendar dates, the wiggles in the calibration curve are the real problem.
14. Radiocarbon generated by atmospheric testing of nuclear weapons (bomb radiocarbon) produced a strong signal with an abrupt onset in the 1950s, which serves as a dated marker for tracing oceanic circulation and confirming age in animals forming growth bands.
15. Caveat that • All of the Caveats that apply to radiocarbon dating apply to its use in authentication.
16. One bone has been radiocarbon dated to 200 BCE; forest destruction by humans may have contributed to its extinction.
17. So the radiocarbon clock is no longer regarded as yielding an absolute chronology but one which measures only relative dates.
18. The characteristic terrace morphologies and alluvial sediment sequences are briefly described, but most importantly, the deposits are radiocarbon dated for many sites.
19. Similarly, radiocarbon dating of American east coastal subfossil remains confirm that gray whales existed there at least through the 17th century.
20. An independent chronology for these reconstructions is essential and this is provided by radiocarbon-dating of organic material preserved in the sediments.
21. Radiocarbon dating suggested that the chickens were Pre-Columbian, and DNA analysis showed that they were related to prehistoric populations of chickens in Polynesia.
22. In 1988, three radiocarbon dating tests dated a corner piece of the shroud from the Middle Ages, between the years 1260 and 1390.
23. 18 The team obtained the date of 9260 years ago for the coprolite by radiocarbon dating one of the prickly pear seeds inside.
24. 23 Using radiocarbon techniques on sediments collected from four rivers, they determined that bacteria may alter riverine carbon, making it indistinguishable from ocean carbon.
25. According to the tests carried out by Oxford University Radiocarbon Accelerator Unit, "with a probability of more than 95%, the parchment was from between 568 and 645".
26. Between 1995 and 1998, Accelerator mass spectrometry radiocarbon dating of Zyzyphus cf. nummularia charcoal found in the quarries has yielded evidence that the activity continued into 1870-1800 BCE.
27. Radiocarbon-dated alluvial terrace sequences in Alberta show generally comparable trends of rapid early creek incision followed by partially overlapping episodes of net aggradation and degradation from basin to basin.
28. Since the radiocarbon date came from the lowermost and oldest layer of mound-fill underlying the andesite and sandstone stonework, the stonework must have been constructed sometime after AD 536–600.
29. Each of these settlement phases (ÇuHö I–XIII) was relatively dated on the basis of material studies (mainly ceramics) but also using absolute chronology from over 100 radiocarbon dates.
30. A synthesis of 25 years of work, Athapaskan Migrations includes detailed accounts of field research in which the authors emphasize ethnic group identification, settlement patterns, lithic analysis, dendrochronology, and radiocarbon dating.
31. The effect of coal degradation processes by aerated waters on the radiocarbon content is demonstrated regarding a case study in a small coal basin near Leipzig with former underground mining.
32. Patrut began studying Baobabs in the early 2000s, and he has spent much of the last 15 years identifying more than 60 of the largest, oldest specimens and using radiocarbon dating to …
33. Do these admissions give reason to suspect that perhaps the tree-ring chronology is not as well-anchored as it seems to be, but that its proponents look for support to radiocarbon dating?
34. ‘In a ‘calorimeter’ a substance can be Combusted in the presence of oxygen, to measure the amount of heat generated per gram.’ ‘After washing and drying, it was Combusted to recover any carbon dioxide for the radiocarbon analysis.’
35. The oldest known sandals (and the oldest known footwear of any type) were discovered in Fort Rock Cave in the U.S. state of Oregon; radiocarbon dating of the sagebrush bark from which they were woven indicates an age of at least 10,000 years.
36. The Archaic-Early Basketmaker Period in Chaco, radiocarbon dated from about 7000 to 1500 years before present, is also characterized by a mobile, hunting-gathering, non-ceramic economy, but there is an increasing emphasis on gathering, cultivation, and food storage through time.
37. Wright present the results from the excavation of the so-called Pise Building in area TC of Tell Brak.This is a low-status residential complex which is dated by means of pottery comparisons and radiocarbon dates to the post-Akkadian period (EJZ 4c in ARCANE terminology).
38. Neanderthals and Homo sapiens could not have Coexisted for more than a millennium in the Cantabrian Region, which reduces significantly the possibilities for interaction between the two groups and tends to reinforce the hypothesis of an intrinsic cause of extinction, according to a study based on radiocarbon dates from thirteen archaeological sites in this area of southwestern Europe.