Investigation of molecular motions and interprotein interactions in solutions by NMR and TDDS

Applied Magnetic Resonance - Non-selective NMR relaxation of protein and water protons at various resonance frequencies as well as Time Domain Dielectric Spectroscopy (TDDS) were applied to study...     

Approximation of number π by algebraic numbers from special fields

The estimate from below of the modulus of the difference between π and algebraic numbers from the fields generated by the roots of unity is made.     

Recent results in electron-positron annihilation above 2 GeV

We review recent results in electron-positron annihilation above a center-of-mass energy of 2 GeV with particular emphasis on the production and properties of new particles. Topics include the total e⁺e^? cross section, the properties of jet-like structure in high energy multi-particle events, the properties of the Ψ family of charmonium states, the production and properties of the charmed D mesons, and evidence for and the properties of the τ, a new charged lepton.     

Arytenoid dislocation

Arytenoid dislocation is a common yet infrequently diagnosed complication of laryngeal trauma. It may result in various symptoms, including permanent dysphonia, although immediate voice change is not always present. Early reduction is the treatment of choice; however, late reduction is often successful in restoring voice. A high index of suspicion based on the history of the patient is necessary to recognize arytenoid dislocation. Thorough physical examination and objective tests are helpful in confirming this diagnosis.     

The atomic absorption spectroscopy of chromium

Conditions were studied for the determination of trace amounts of chromium by atomic absorption spectroscopy. Solution matrix, flame composition, and extraction procedures were the variables studied. A detection limit of 0.006 p.p.m. of chromium was observed with an air-hydrogen flame and methyl isobutyl ketone as the solvent.     

Elastic constants of 2H-MoS2 and 2H-NbSe2 extracted from measured dispersion curves and linear compressibilities

Recent neutron data on the dispersion curves and X-ray measurements of the linear compressibilities of the 2H polytypes of MoS₂ and NbSe₂ have been used to obtain approximate values of the five independent elastic constants of these materials. In the case of NbSe₂ sufficient information is available to over-determine the elastic constants and the results are self consistent within estimated uncertainties, although the uncertainties are especially large for c₃₃ and c₁₁. Additional related considerations such as Debye temperatures and model calculations of c₃₃, and c₄₄ are also made. It is found that there is significant and unexplained disagreement between the value of the low temperature specific heat Debye temperature of NbSe₂ and the value determined on the basis of the elastic constants, but that the model predictions of c₃₃ and c₄₄ are in satisfactory agreement with the values extracted from the neutron data for both MoS₂, and NbSe₂.     

Molecular beam epitaxy and reconstructed surfaces

In the last years molecular beam epitaxy (MBE) has become a very important method to create new materials. Scattering and channeling of high-energy ions is a mass-dispersive, surface-sensitive crystallographic technique, particularly suited for the investigation of epitaxial systems. The combination of both techniques allows new insight into some of the fundamental processes at interfaces and surfaces. As an example we discuss the influence of substrate reconstruction on epitaxial growth. We show for the Si/Ge and Si/Si systems that the reordering of the reconstruction-induced displacements at the substrate surface, a necessary condition for epitaxial growth, is critically dependent on the type of reconstruction: Deposition of Ge or Si on Si(100)2×1 at room-temperature relieves the reconstruction, whereas Si(111)7×7 appears unaffected. This difference is discussed in terms of structural models for these surfaces. We shall also discuss the implications of these results with respect to MBE and, in particular, to Si homoepitaxial temperatures.     

Multiline short pulse amplification and compression in high gain CO2 laser amplifiers

Theoretical studies are presented for the amplification and compression of multiline short pulses of CO₂ laser radiation at 10.6 μ in a high gain, CO₂ laser amplifier. A method of efficiently generating high energy, subnanosecond pulses of CO₂ laser radiation is proposed utilizing a pulse tailoring technique recently disclosed by Figueira and Sutphin.