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Freshman Organic Chemistry (CHEM 125)
Half a century before direct experimental observation became possible, most structures of organic molecules were assigned by inspired guessing based on plausibility. But Wilhelm Körner developed a strictly logical system for proving the structure of benzene and its derivatives based on isomer counting and chemical transformation. His proof that the six hydrogen positions in benzene are equivalent is the outstanding example of this chemical logic but was widely ignored because, in Palermo, he was far from the seats of chemical authority.
00:00 – Chapter 1. How Did Kekule Know Benzene is Hexagonal?
20:10 – Chapter 2. Koerner’s System of Isomer Counting and Chemical Transformation
29:53 – Chapter 3. Koerner’s Assumptions on Replacement and Experimental Distinguishability
34:22 – Chapter 4. The Koerner Equivalence Proof
Complete course materials are available at the Open Yale Courses website: http://open.yale.edu/courses
This course was recorded in Fall 2008.
FOXSEW Automatic Tape Cutter (Hot and Cold Knife)
Applications: Velcro tapes, strip tapes, ribbon tape, bag band small webbing, woven label, printed label, ribbon tape, bag bands, seat belts, belt loop, bag band, shrink tube, string, elastic band, plastic zipper etc.
Working Video 1: www.foxsew.com/company-video/auto-tape-cutter-machine-hot-and-cold-knife-205.html
Working Video 2: www.foxsew.com/company-video/automatic-ribbon-cutting-machine-206.html
Working Video 3: www.foxsew.com/company-video/automatic-ribbon-tape-cutter-207.html
Working Video 4: www.foxsew.com/company-video/automatic-tape-cutting-machine-208.html
Working Video 5: www.foxsew.com/company-video/automatic-heavy-duty-webbing-cutting-machine-318.html
Details: High speed: It can cut 100 cut per minute. (50mm long)
Accuracy: Cut-length is accurate cutting to a stepping motor
Cutting type: Cutting is neat due to using a cold cutter which is durable.
Automatic operation: It works automatically only by setting length and quantity
Automatic stopper: It stops automatically if materials run out during operation.
Memory: Set-length, set-q’ty & set-speed are not erased even if power off & on.
Applications: Velcro tapes, strip tapes, ribbon tape, bag bands, small webbing, woven label, printed label, ribbon tape, bag band, belt loop, bag band, shrink tube, string, elastic band, plastic zipper etc…