RESEARCH & TECHNOLOGY
1
The Chemical World This Week FEBRUARY 22. 19 β 5 S£S£ CONCENTRATES ί A computer method for determining the atomic structure of alloys has been developed by Dr. Jerome B. Cohen and Pierre Gehlen of Northwestern University (Evanston, 111.). The method uses X-ray diffraction information and an IBM 709 digital computer. Alloys studied were copper-gold and copper-aluminum. First an X-ray diffraction study is run. This gives two-dimensional data on distances and average distribution of atoms in the alloys. Next the approximate location of each atom in a random arrangement is programed into the computer, NU's Dr. Lyle Schwartz told the American In- stitute of Mining, Metallurgical, and Petroleum Engineers' meeting, in Chicago. Then the X-ray information (indicating the correct position of each atom ) and a mathematical means of deter- mining the atom's three-dimensional position are given to the computer. The computer "experi- ments'' with each atom, removing it from the random structure and placing it in a location that seems most logical and correct according to the X-ray data. Finally, the computer's automatic printer draws diagrams showing two-dimensional cross sections of the atoms which can be stacked atop one another to give a three-dimensional map. ί Japan's JRR-2, enriched uranium, heavy water moderated research reactor reached its peak power of 10,000 kw(t). last week. The reactor, built by the Japan Atomic Energy Research Institute at Tokai-Mura, Ibaraki Prefecture ( some 60 miles northeast of Tokyo), has just wound up two years of performance and safety tests. The reactor's purpose is basic research, materials and engineering testing, and experimental isotope production. The country also has one 12,500 kw(e). enriched uranium, light-water moderated power reactor on stream at Tokai-Mura, and another natural uranium, graphite-moderated power reactor—166,000 kw(e).—under construc- tion and scheduled to start up next month. ί A new breeding approach to higher yielding corn hybrids may result from research at Uni- versity of Illinois. Basis for the approach is an enzyme, nitrate reductase. The enzyme initiates a process which reduces fertilizer nitrate to am- monia needed to produce amino acids. For two consecutive years, inbred lines of corn hybrids were evaluated for nitrate reductase activity throughout the growing season, Illinois' plant physiologist R. H. Hageman told the 17th Annual Midwest Fertilizer Conference, held in Chicago last week. The inbreds were subdivided into categories of high and low levels of activity; in- breds from these categories were crossed by Dr. E. R. Leng of the agronomy department to give three groups of material: high-by-high, high-by- low, and low-by-low. Activity level in each hybrid was then compared with its two parental inbreds by Dr. Hageman. Hybrids of the high- by-high group were slightly lower in enzyme activity than their parental inbreds, he finds. Activity of the high-by-low group was about intermediate. In the low-by-low group, how- ever, one hybrid showed a higher level of enzyme activity. "These results should provide a basis for developing genetic models that could lead to more efficient and productive corn hybrids," Dr. Hageman says. • A superconducting magnetic coil made from niobium-tin wire has produced a field of up to 132,000 gauss. The coil, made by scientists at General Electric Research Laboratory (Schenec- tady, N.Y. ), uses 3500 feet of the niobium-tin wire. It consists of four coaxial sections of in- creasing diameter, has an outside diameter of 3 inches, and is 6 inches long. The field exists in a 1 /4-inch diameter hole along the coil's axis. Larger working volumes are obtained by remov- ing one or more of the coil's inner sections. The coil is kept at —452° F. by immersion in liquid helium in a stainless steel container. At this temperature, the 132,000-gauss field is achieved by using 6-volt storage batteries to produce more than 50,000 amperes per square centimeter. CE's Carl H. Rosmer designed the magnet. ^ Thermoplastic polymers made by vapor phase polymerization of p-xylylene have been intro- duced commercially by Union Carbide's plastics division. Generically, the series is called pary- lene, with parylene Ν ( poly-p-xylylene ) the basic member. The polymer is made by bringing heated monomer vapor into contact with a cool surface; the vapor condenses and polymerizes to a thin film of transparent plastic. Production is on a semiworks scale at Bound Brook, N.J. Al- though many members of the series are feasible, only two are currently available commercially: parylene Ν and parylene C—the latter being poly ( monochloro-/;-xylylene ). Applications in- clude use as a dielectric in capacitors, as protec- tive coatings, and as encapsulating materials for solid chemicals. FEB. 2 2, 1965 C&EN 35
Transcript of RESEARCH & TECHNOLOGY
The Chemical World This Week FEBRUARY 22. 19 β 5
S£S£ CONCENTRATES ί A computer method for determining the
atomic structure of alloys has been developed by Dr. Jerome B. Cohen and Pierre Gehlen of Northwestern University (Evanston, 111.). The method uses X-ray diffraction information and an IBM 709 digital computer. Alloys studied were copper-gold and copper-aluminum. First an X-ray diffraction study is run. This gives two-dimensional data on distances and average distribution of atoms in the alloys. Next the approximate location of each atom in a random arrangement is programed into the computer, NU's Dr. Lyle Schwartz told the American Institute of Mining, Metallurgical, and Petroleum Engineers' meeting, in Chicago. Then the X-ray information (indicating the correct position of each atom ) and a mathematical means of determining the atom's three-dimensional position are given to the computer. The computer "experiments'' with each atom, removing it from the random structure and placing it in a location that seems most logical and correct according to the X-ray data. Finally, the computer's automatic printer draws diagrams showing two-dimensional cross sections of the atoms which can be stacked atop one another to give a three-dimensional map.
ί Japan's JRR-2, enriched uranium, heavy water moderated research reactor reached its peak power of 10,000 kw(t) . last week. The reactor, built by the Japan Atomic Energy Research Institute at Tokai-Mura, Ibaraki Prefecture ( some 60 miles northeast of Tokyo), has just wound up two years of performance and safety tests. The reactor's purpose is basic research, materials and engineering testing, and experimental isotope production. The country also has one 12,500 kw(e). enriched uranium, light-water moderated power reactor on stream at Tokai-Mura, and another natural uranium, graphite-moderated power reactor—166,000 kw(e).—under construction and scheduled to start up next month.
ί A new breeding approach to higher yielding corn hybrids may result from research at University of Illinois. Basis for the approach is an enzyme, nitrate reductase. The enzyme initiates a process which reduces fertilizer nitrate to ammonia needed to produce amino acids. For two consecutive years, inbred lines of corn hybrids were evaluated for nitrate reductase activity throughout the growing season, Illinois' plant physiologist R. H. Hageman told the 17th Annual
Midwest Fertilizer Conference, held in Chicago last week. The inbreds were subdivided into categories of high and low levels of activity; inbreds from these categories were crossed by Dr. E. R. Leng of the agronomy department to give three groups of material: high-by-high, high-by-low, and low-by-low. Activity level in each hybrid was then compared with its two parental inbreds by Dr. Hageman. Hybrids of the high-by-high group were slightly lower in enzyme activity than their parental inbreds, he finds. Activity of the high-by-low group was about intermediate. In the low-by-low group, however, one hybrid showed a higher level of enzyme activity. "These results should provide a basis for developing genetic models that could lead to more efficient and productive corn hybrids," Dr. Hageman says.
• A superconducting magnetic coil made from niobium-tin wire has produced a field of up to 132,000 gauss. The coil, made by scientists at General Electric Research Laboratory (Schenectady, N.Y. ), uses 3500 feet of the niobium-tin wire. It consists of four coaxial sections of increasing diameter, has an outside diameter of 3 inches, and is 6 inches long. The field exists in a 1/4-inch diameter hole along the coil's axis. Larger working volumes are obtained by removing one or more of the coil's inner sections. The coil is kept at —452° F. by immersion in liquid helium in a stainless steel container. At this temperature, the 132,000-gauss field is achieved by using 6-volt storage batteries to produce more than 50,000 amperes per square centimeter. CE's Carl H. Rosmer designed the magnet.
^ Thermoplastic polymers made by vapor phase polymerization of p-xylylene have been introduced commercially by Union Carbide's plastics division. Generically, the series is called pary-lene, with parylene Ν ( poly-p-xylylene ) the basic member. The polymer is made by bringing heated monomer vapor into contact with a cool surface; the vapor condenses and polymerizes to a thin film of transparent plastic. Production is on a semiworks scale at Bound Brook, N.J. Although many members of the series are feasible, only two are currently available commercially: parylene Ν and parylene C—the latter being poly ( monochloro-/;-xylylene ). Applications include use as a dielectric in capacitors, as protective coatings, and as encapsulating materials for solid chemicals.
F E B . 2 2, 1 9 6 5 C & E N 35
