alytical journals seem to be trying to keep publication times under this value. T h i s t h e n is t h e p i c t u r e of p u b l i c a t i o n a c t i v i t y in a n a l y t i c a l c h e m i s t r y a s we s e e it: a d y n a m i c a l l y g r o w i n g field, w i t h a d o u b l i n g t i m e of a b o u t 14 years, d o m i n a t e d by t h e U.S.S.R. a n d t h e U . S . , w i t h a b o u t 12 c o r e j o u r n a l s , and having a publication time (receipt of m a n u s c r i p t t o p r i n t ) of a b o u t six months. Analytical chemistry makes u p a b o u t 8% of t h e t o t a l c h e m i c a l lite r a t u r e a n d a p p a r e n t l y will c o n t i n u e t o h o l d t h a t s h a r e in t h e f u t u r e .
(8) W. S. Lyon, Scientometrics (in press), 1980. (9) F Narin, M. P. Carpenter, J. Am. Soc. Inf.ScL, 26,80(1975). (10) K. O. May, Science, 154,1672 (1966). (11) E. J. Crane, Chem. Eng. News, 27, 529 (1949). (12) D. B. Baker, Chem. Eng. News, 39, 78 (1961). (13) D. B. Baker, Chem. Eng. News, 44, 84 (1966). (14) D. B. Baker, Chem. Eng. News, 49, 37 (1971). (15) D. B. Baker, Chem. Eng. News, 54, 23 (1976).
(16) "CAS Today, Fact and Figures about Chemical Abstracts Service," American Chemical Society, Washington, D.C., 1974. (17) Ch. C. Holt, W. E. Schrank, Amer. Docum., 18,18 (1968). (18) S. C. Bradford, "Documentation," Crosby, London, 1978. (19) E. Garfield, Journal Citation Reports, Vol. 9, Institute for Scientific Information, Philadelphia, Pa., 1976 Annual. (20) J. M. Petruzzi, Anal. Chem., 5 1 , 277A (1979). (21) Letter, Anal. Chem. 50, 12A (1978).
Research sponsored by the Office of Energy Research, U.S. Department of Energy under contract W-7405-eng. 26 with the Union Carbide Corp.
Appendix Let us use the " t o t a l " analytical chemistry curve. T h e doubling time of t h e " r a w " d a t a from 1935 to 1975, i.e., the "linear e n d " of the curve gives Ta 0 = 11.99 y (see Figure 1). Using this value we can get the extrapolated figure for the year 1915, which is 11 380. T h e difference between this and the original 4980 value is Nj = 6400 (the first correction) By adding this value to each point of the curve and calculating the new doubling time we get T ^ = 12.79 y. Extrapolating again to the year 1915 the difference between this figure and the former (already corrected) value gives N2 = 2660 (the second correction), with T d 2 = 13.12 y Going on, the third correction is N 3 = 1140 T h e Ni, N2, N3 values are the elements of an infinite geometrical series (it is an experimental observation without any theoretical foundation b u t valid for all t h e cases!) with a quotient qi = N 2 / N i = 2660/6400 = 0.415 and q 2 = N3/N2 = 1140/2660 = 0.428 Using the average value of'0.421, the sum of this converging series is S - N i / 1 - q = 6400/0.579 = 11 053 T h e total estimated correction, i.e., the number of papers published before 1915 is 11 053. By adding this value to each point of the curve the following doubling time: T d = 13.87 y is obtained (Figure 2). For curiosity, as " s t a r t i n g " year of analytical chemistry (i.e., extrapolating this corrected curve to zero), 1740 was obtained, which is not unbelievable.
Making things crystal-clear just got a whole lot faster. The technique is called X-ray powder diffractometry; our version comes in a system called the Philips APD 3600. But we think "powder" is misleading. That only scratches the surface. You can accurately analyze polycrystalline compounds in a variety of ways. All of them very fast—thanks to the efficient use of the computer in our 3600. You can interact and change operating parameters in real-time. You get ditfractograms in minutes that are normalized for weak and strong signals, with spurious or unwanted radiation and background noise removed. Then the 3600 lets you search agaihst standards or your own special profiles. That adds up to fast throughput of samples; in some applications you can even do hundreds a day. Spending less time collecting data, gives you more time for identifying phases. This inherent speed and versatility make the 3600 ideal for both qualitative and quantitative analysis. To make it even more crystal-clear, why not send for more information. Just write or call, Philips Electronic Instruments, 85 McKee Drive, Mahwah, N.J. 07430. (201)529-3800. A North American Philips Company. It only took about five minutes to get this complete diffractogram on this unknown "rock" sample. It took just another twenty minutes to come up with a "fit" from our computerized search program that contains the JCPDS file for 36,000 compounds. If necessary, you can generate your own data files—all internally and privately.
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References (1) R. R. Brooks, L. E. Smythe, Talanta, 22, 495 (1975). (2) F. S. Boig, P. W. Howerton, Science, 115,555(1952). (3) R. B. Fischer, Anal. Chem., 37, 27A (1965). (4) I. M. Orient, Zauodsk, Lab., No. 9, 1071 (1975)." (5) T. Braun, Talanta, 23, 743 (1976). (6) W. S. Lyon, Anal. Chem., 45, 386A (1973). (7) T. Braun, W. S. Lyon, and E. Bujdoso, Anal. Chem., 49, 682A (1977).
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ANALYTICAL CHEMISTRY, VOL. 52, NO. 6, MAY 1980 • 629 A
