Marketing Metrics to the American Public: An Interview with Dr. Eugene Laczniak

One of the major problems confronting the metrication movement is the general lack of publicity and public awareness of the scope of the metric system. The work already performed as well as that still needed to be done to bring metrication to fruition needs considerable attention. The application of marketing principles and programs can have a potentially great effect on the success of the work of metric activists. During the course of this interview, conducted in late November, 1977, Dr. Eugene Laczniak suggests some of the ways in which marketing can be made to work for metrication; and he offers vital insights into the means by which metrication can become a fixed reality in American life, business, industry, government, and education

Correlations in self-bound systems of identical fermions

A method for the calculation of translationally invariant wave functions for systems of identical fermions with arbitrary potential of pair interaction is developed. It is based on the well-known result that the essential dynamic part of the Hamiltonian for the system of identical particles is the Reduced Hamiltonian operator describing relative movement of two particles inside the system. The eigenfunctions of this operator take into account all correlations caused by interaction. These eigenfunctions are basic for the construction of the components (i.e. the functions with a lower degree of antisymmetry) of the system wave functions. The main problem of this approach appears to be antisymmetrization of the components. The developed universal algorithm for antisymmetrization gives a possibility to perform this operation in a simple way and keep numerical approximations under control.Comment: 20 pages REVTeX, submitted to Lithuanian J. Phy

Simulation of Gate Lag and Current Collapse in Gallium Nitride Field-Effect Transistors

Results of two-dimensional numerical simulations of gate lag and current collapse in GaN heterostructurefield-effect transistors are presented. Simulation results clearly show that current collapse takes place only if an enhanced trapping occurs under the gate edges. Hot electrons play an instrumental role in the collapse mechanism. The simulation results also link the current collapse with electrons spreading into the buffer layer and confirm that a better electron localization (as in a double heterostructurefield-effect transistor) can dramatically reduce current collapse

Simulation of Hot Electron and Quantum Effects in AlGaN/GaN Heterostructure Field Effect Transistors

We report on simulations of electrical characteristics of AlGaN/(InGaN)/GaN heterostructurefield effect transistors with quantum and hot electroneffects taken into account. Polarization charges lead to quantum confinement of electrons in the channel and to the formation of two-dimensional electron gas. The electron quantization leads to the spread of the electronwave function into the barrier and bulk but does not have significant impact on dc electrical characteristics.Hot electrons play an important part in the charge transport by spilling over into the bulk GaN where they are captured by traps. This leads to negative differential conductivity, which is also observed experimentally. The simulation results are in good agreement with measured dccharacteristics

The Effects of Cholera Toxin on Cellular Energy Metabolism

Multianalyte microphysiometry, a real-time instrument for simultaneous measurement of metabolic analytes in a microfluidic environment, was used to explore the effects of cholera toxin (CTx). Upon exposure of CTx to PC-12 cells, anaerobic respiration was triggered, measured as increases in acid and lactate production and a decrease in the oxygen uptake. We believe the responses observed are due to a CTx-induced activation of adenylate cyclase, increasing cAMP production and resulting in a switch to anaerobic respiration. Inhibitors (H-89, brefeldin A) and stimulators (forskolin) of cAMP were employed to modulate the CTx-induced cAMP responses. The results of this study show the utility of multianalyte microphysiometry to quantitatively determine the dynamic metabolic effects of toxins and affected pathways

Ultrafast relaxation of photoexcited carriers in semiconductor quantum wires: A Monte Carlo approach

A detailed analysis of the cooling and thermalization process for photogenerated carriers in semiconductor quantum wires is presented. The energy relaxation of the nonequilibrium carrier distribution is investigated for the ‘‘realistic'' case of a rectangular multisubband quantum-wire structure. By means of a direct ensemble Monte Carlo simulation of both the carrier and the phonon dynamics, all the nonlinear phenomena relevant for the relaxation process, such as carrier-carrier interaction, hot-phonon effects, and degeneracy, are investigated. The results of these simulated experiments show a significant reduction of the carrier-relaxation process compared to the bulk case, which is mainly due to the reduced efficiency of carrier-carrier scattering; on the contrary, the role of hot-phonon effects and degeneracy seems to be not so different from that played in bulk semiconductors

Synthesis and structure elucidation of 1-aryl-substituted tetrahydropyridone derivatives

Mickevicius V, Vaickelioniene R, Mikulskiene G, Sewald N. Synthesis and structure elucidation of 1-aryl-substituted tetrahydropyridone derivatives. KHIMIYA GETEROTSIKLICHESKIKH SOEDINENII. 2005;(6):874-881.A series of 1-aryl-1,4,5,6-tetrahydro-4(1H)-pyridones having substituents in 2,3- and 2,3,5-positions was prepared from N-aryl-beta-alanines and ethyl acetoacetate or 2,4-pentanedione. Twelve tentative biologically active compounds were identified by the combination of H-1, C-13 and H-1/C-13 NMR spectroscopy. The extensive interest has been focused on the influence of substituents as well as on the number, attachment position and the nature of the substituents. The unknown shielding of the heterocyclic Ring on the aromatic carbon atoms was determined and the averaged chemical shift increments were successfully used for the assignment of the aromatic moiety of the studied compounds. The presence of two chiral elements in compounds 16, 17, 20-21 resulted in the mixture of diastereomers and double sets of the resonances in NMR spectra