Scientific and Technical Aerospace Reports Volume 38 July 28, 2000

20000064660 Abdus Salam International Centre for Theoretical Physics, Trieste, Italy
Acoustic phonon generation in a superlattice under the hopping perpendicular transport
Glavin, B. A.; Linnik, T. L.; Kochelap, V. A.; Sep. 30, 1998; 20p; In English
Report No.(s): DE99-609736; IC-98/135; No Copyright; Avail: Department of Energy Information Bridge
In this work we consider the theory of sound amplification under the hopping perpendicular transport in a semiconductor
superlattice. It is shown that phonons propagating close to the axis of superlattice demonstrate high values of the increment,
exceeding the rates of phonon scattering on natural isotopes. Effects, restricting the value of increment, including the current
induced heating of electrons, are discussed. Influence of the phonon spectrum modification in superlattice on the value of increment
is examined.
NTIS
Phonons; Superlattices
20000064724 Massachusetts Inst. of Tech., Lincoln Lab., Lexington, MA USA
Solid State Research Quarterly Report, 1 Aug.-31 Oct. 1999
Shaver, David C.; Apr. 20, 2000; 69p; In English
Contract(s)/Grant(s): F19628-95-C-0002
Report No.(s): AD-A377032; 1999:4; ESC*-TR-99-060; No Copyright; Avail: CASI; A04, Hardcopy; A01, Microfiche
This report covers in detail the research work of the Solid State Division at Lincoln Laboratory for the period 1 August through
31 October 1999. The topics covered are Quantum Electronics, Electro-optical Materials and Devices, Submicrometer Technology,
Biosensor and Molecular Technologies, Advanced Imaging Technology, Analog Device Technology, and Advanced Silicon
Technology. Funding is provided by several DoD organizations-including the Air Force, Army, BMDO, DARPA, Navy, NSA,
and OSD-and also by the DOE, NASA, and NIST.
DTIC
Solid State Devices; Quantum Electronics; Optoelectronic Devices; Bioinstrumentation
20000065621 Universities Space Research Association, Huntsville, AL USA
Protein Crystals Grow Purer in Space: Physics of Phenomena
Chernov, Alex A., Universities Space Research Association, USA; [2000]; 3p; In English; 1st; Microgravity Research and
Applications in Physical Science and Biotechnology, 10 Sep. 2000, Sorrento, Italy; Original contains color illustrations
Contract(s)/Grant(s): NCC8-66; No Copyright; Avail: CASI; A01, Hardcopy; A01, Microfiche
This presentation will summarize the quantitative experimental and theoretical results obtained by B.R. Thomas, P.G. Vekilov,
D.C. Carter, A.M. Holmes, W.K. Widierow and the Author, the team with expertise in physics, biochemistry, crystallography
and engineering. Impurities inhomogeneously trapped by a growing crystal - e.g., producing sectorial structure and/or striations
- may induce macroscopic internal stress in it if an impurity molecule has slightly (less than 10%) different shape or volume than
the regular one(s) they replace. We tested for the first time plasticity and measured Young modulus E of the triclinic, not crosslinked
lysozyme by triple point bending technique. Triclinic lysozyme crystals are purely elastic with E similar or equal to 1/5
(raised dot) 10 (exp 9) partial derivative yn/sq cm. The strength limit, sigma (sub c) similar or equal to 10 (exp -3)E similar or
equal to Epsilon (sub c), where sigma (sub c) and epsilon (sub c) are critical stress and strain, respectively. Scaling E and sigma
(sub c) with the lattice spacing suggests similar binding stiffness in inorganic and biomolecular crystals. The inhomogeneous internal
stress may be resolved in these brittle crystals either by cracking or by creation of misoriented mosaic blocks during, not after
growth. If each impurity molecule induces in the lattice elementary strain epsilon (sub 0) similar or equal to 3 (raised dot) 10 (exp
-2) (this is maximal elementary strain that can arise at the supersaturation DELTA mu/kT similar or equal to 2 and macroscopic
molecular concentration difference between subsequent macrolayers or growth sectors is partial derivativeC similar or equal to
5 (raised dot) 10 (exp -3), the internal strain epsilon similar or equal to epsilon (sub 0) partial derivative C similar or equal to 10
(exp -4). Mosaic misorientation resolving such strain is approximately 30 arcsec. Tenfold increase of impurity concentration may
cause cracking. Estimates of stress in an isometric sectorial crystal show that lysozyme crystals can tolerate the stress till the size
of 0.5mm. Dissolving mosaic lysozyme crystal shows that the mosaicity, indeed, is absent below that size.
Derived from text
Crystallography; Proteins; Crystal Growth; Mathematical Models; Physics
20000067636 NASA Marshall Space Flight Center, Huntsville, AL USA
Macromolecule Crystal Quality Improvement in Microgravity: The Role of Impurities
Judge, Russell A., NASA Marshall Space Flight Center, USA; Snell, Edward H., NASA Marshall Space Flight Center, USA;
Pusey, Marc L., NASA Marshall Space Flight Center, USA; Sportiello, Michael G., Colorado Univ., USA; Todd, Paul, Colorado
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