RADIATION MATERIALS CORPORATION - Analytical Chemistry (ACS

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68' Kintrac VII is a spectrophotometric system for automatically monitoring the kinetics of chemical reactions. The system permits programmed examination of up to seven different samples at a time, either continuously or sequentially. Kintrac VII is a single-beam, modulated signal spec-

trophotometric recording system, with a wavelength range of 190 to 750 nm. Photometric range is 0 to 3A and any absorbance span may be independently set for each of the seven channels over the entire range. Beckman Instruments, Inc., 2500 Harbor Blvd., Fullerton, Calif. 92634 408

Test Tube H o l d e r f o r M a g n e t i c

Stirring Test tubes are held firmly in a vertical position making it possible to drop in a micro stirring bar and setting up the tube on a magnetic stirrer. Constructed of clear methacrylate plastic, the holder has a base of 3 " in diameter and height of 2 1 / 2 " . It will accomodate tubes from 1 / 2 " to l 1 / » " outside diameter and permits observation of the contents at all times. The Chemical Rubber Co., 18901 Cranvrood Parkway, Cleveland, Ohio 44128 410

40 J . V/pages Radiation Materials Corporation a n n o u n c e s t h e p u b l i c a t i o n o f its new catalog "Radiation 1 " , bringing t o y o u t h e b r o a d e s t a n d m o s t c o m p l e t e line of r a d i o a c t i v e s o u r c e s in t h e f i e l d . R M C a n d its t e c h n i c a l staff are r e a d y t o a s s i s t y o u in t h e preparation of sources to meet your most exacting requirements. S e n d t o - d a y f o r y o u r f r e e 40 p a g e c o p y of " R a d i a t i o n 1 "

RADIATION MATERIALS C O R P O R A T I O N 124 C a l v a r y Street Waltham, Mass. 02154 Tel. (6 1 7 ) 899-6350 Circle No. 112 on Readers' Service Card

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ANALYTICAL CHEMISTRY

Automatic liquid scintillation analyzer supplies reliable and immediately usable print-out data. The features include electronic computation with eight measuring and ten computing printer program boards, automatic 14 C subtraction in 3 H channel, a collimated external standard, dead time correction, low count reject, and two separate external standardization channels. Norelco, Philips Electronic Instruments, 750 S. Fulton Ave., Mount Vernon, N.Y. 10550 409

Ratiometer, Model 1 5 1 , takes the ratio of any two dc signals even while they both vary rapidly in amplitude (over 100:1 dynamic range). The system features a unique scale expansion technique and chopper stabilization to completely eliminate zero drift problems. Response time is 2 0 milliseconds to accommodate rapid variations of the input signals. Brower Laboratories, Inc., Turnpike Rd. (Route 9), Westboro, Mass. 0 1 5 8 1

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