Dating range

The end of the 1980 s saw the application of TIMS to U-series measurement (Chen et al. 1986 Edwards et al. 1987 Goldstein et al. 1989). This represented a major technological advance. Analysis time was reduced from one week to several hours, sample sizes for many carbonate or volcanic rock samples decreased from -10-100 pg to 0.1-1 ug U or Th, measurement precision improved from percent to permil levels, and for the decay series, the dating range was extended from 350,000 years to... 

In the past three years, MC-ICPMS has emerged as an alternative to TIMS for precise measurement of the U-series isotopes with comparable or better precision. U-Th isotopes can now be routinely measured at the sub-permil level. Previously, this had only been demonstrated using charge-collection TIMS applied to thorium isotope measurement. Data collection efficiency, sample size requirements, and detection limits can also be greatly improved over TIMS. For the U- U- Th system applied to carbonate samples, this has extended the dating range beyond 600,000 years, and °Th-age uncertainties of 2000 years are now attainable on 300,000 year-old samples (e g., Stirling et al. 2001). 

This version uses a more complex representation, not detailed here, to maintain the events so that they are indexed directly by their date ranges. This data structure is encapsulated behind an interface called EventContainer that does all the real work. 

Sample dates Range Mean Monthly mean... 

Figure 2 shows the numerical results of the residual electron density for various values of Ta. The values of other parameters used in the calculation are tabulated in Table I. The values of TG reported to date range from 312... 

Means of Calibrating Racemization Rates. Theoretically, the racemization technique has an eflFective dating range of 500,000 years in cool temperate environments. One problem in working with these older samples is finding an appropriate calibration sample. Radiocarbon-dated bones 17-20,000 years old provide suitable calibrations for the last... 

Location/occupation Sampling dates Range Mean Reference... 

Advanced search—options for searching front page or fulltext, limiting the date range, and sorting results chronologically or by relevance. 

Where the potentials agree, there is of course the chance that the agreement is due to a fortuitous correspondence of interferences. This is probably the case for well 7, where traces of O2, DOC, and sulfide have unknown effects on electrode potentials, and ORP s recorded at this well on other dates range from 17 to 321 mV. We believe, however, that in most groundwater systems, agreement between WIG and Pt electrodes indicates that Ehj corresponds to a nernstian Fe(III)/Fe(II) potential. 

The choice of date range is arbitrary. The number of journal articles for each year was obtained from a search of electronic version of English-based polymer and polymer-related journals using the keywords polyolefin and blends. Within polyolefin keyword, the subkeywords used in the search were polyethylene (PE, LLDPE, LDPE, HDPE, UHMWPE, PE, etc.), polypropylene (PP, iPP, sPP, aPP, etc.), polybutene-1, poly-4-methylpentene-l, ethylene-diene monomer, ethylene-propylene-diene terpolymer, ethylene propylene rubber, thermoplastic olefins, natural rubber (NR), polybutadiene, polyisobutylene (PIB), polyisoprene, and polyolefin elastomer. For the polyolefin blends patent search, polymer indexing codes and manual codes were used to search for the patents in Derwent World Patent Index based on the above keywords listed in the search strategy. 

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