Drift velocity of electrons in silicon at high electric fields from 4.2° to 300°K

The drift velocity of electrons in silicon at high electric fields is measured in the direction over the range of lattice temperatures from 4.2° to 300°K. It is established that in this range a limiting drift velocity exists. Its temperature dependence is measured. The samples used and the method of measurement are briefly described

Differential Step Response of Unipolar Space-Charge-Limited Current in Solids

The small signal step response of unipolar space‐charge‐limited current in solids is analyzed for planar structures and for media in which the drift velocity of the charge carriers is either proportional to the electric field (thermal charge carriers) or is independent of the electric field (hot charge carriers). Results are reported in analytical and graphical form. Their features are discussed in terms of the underlying physical phenomena, as well as in the perspective of experimental applications. Cylindrical and spherical structures are not accessible to closed‐form solutions by the approach

Left-right asymmetries and exotic vector-boson discovery in lepton-lepton colliders

By considering left-right (L-R) asymmetries we study the capabilities of lepton colliders in searching for new exotic vector bosons. Specifically we study the effect of a doubly charged bilepton boson and an extra neutral vector boson appearing in a 3-3-1 model on the L-R asymmetries for the processes $e^-e^-\to e^-e^-$, $\mu^-\mu^-\to\mu^-\mu^-$ and $e^-\mu^-\to e^-\mu^-$ and show that these asymmetries are very sensitive to these new contributions and that they are in fact powerful tools for discovery this sort of vector bosons.Comment: RevTeX, 22 pages, 12 eps figure

Psychometric Evaluation of an Instrument to Measure Hispanic Mothers’ Normative Beliefs, Intentions, Past Experience and Past Behavior Related to the Discussion of Sex-Related Topics with their Adolescent Daughters

Aim: The aim of this project was to describe the psychometric properties of a recently developed instrument that measures Hispanic mother normative beliefs, intentions, past experience, and past behavior regarding the Discussion of Sex-Related Topics (DSRTs) with their adolescent daughters. Background: The DSRTs between Hispanic mothers and their adolescent daughters is important because this interaction has been found to be a protective factor against the daughter’s risk for STDs and unintended pregnancy. Hispanic mother talk less with their daughters about sex-related topics (SRTs) than other ethnic groups. The Rodriguez Normative Belief Instrument (RNBI) has been established to measure normative beliefs, normative beliefs, past behavior, and past experience regarding Hispanic mothers’ DSRTs with their adolescent daughters. Method: The 44-item RNBI was developed based on the Theory of Planned Behavior and the Parent-Based Expansion Theory of Planned Behavior. A convenience sample of 119 Hispanic mothers of adolescent females grades 6 through 8 from two Midwestern Catholic Middle Schools was enrolled completed the instrument. Paper and pen instruments were administered in the language of the participant’s choice, English or Spanish. Results: The entire RNBI and each of the four subscales demonstrated acceptable internal consistency (Cronbach’s alpha = .70). The overall reliability of the RNBI was .82 with the normative beliefs subscale of .85, intentions .88, past behavior .89, and past experience .88. Confirmatory factor analysis validated the four subscales. Conclusion: Psychometric analyses indicated that the RNBI demonstrates acceptable validity and reliability for this sample

A supersymmetric 3-3-1 model

We build the complete supersymmetric version of a 3-3-1 gauge model using the superfield formalism. We point out that a discrete symmetry, similar to the R-symmetry in the minimal supersymmetric standard model, is possible to be defined in this model. Hence we have both R-conserving and R-violating possibilities. Analysis of the mass spectrum of the neutral real scalar fields shown that in this model the lightest scalar Higgs has a mass upper limit, and at the tree level it is 124.5 GeV for a given illustrative set of parameters.Comment: RevTex, extended and revised version, 20 pages, one eps figur

Separation of n-hexane - ethyl acetate mixture by azeotropic batch distillation with heterogeneous entrainers

In this article, a systematic study of the separation of the n-hexane - ethyl acetate mixture with an entrainer by heterogeneous azeotropic batch distillation is performed. Based upon the thermodynamic behaviour of the ternary mixtures, potential entrainers partially miscible with one or two original azeotropic components are chosen. In all cases, the entrainer adds a heterogeneous binary or ternary azeotrope that is the lowest boiling point in the ternary diagram. Therefore, it leaves the column by the overhead stream which is subcooled to get two liquid phases in the decanter. The phase with the highest amount of the original component is removed as distillate product whereas the entrainer – rich phase is continuously refluxed to the column. Considering methanol, acetonitrile, water and nitromethane as heterogeneous entrainers, screening was performed based on the composition of the unstable heteroazeotropic mixture, the ratio of both liquid phases in the condensed top vapour and the purity of the distillate product determined by the liquid – liquid envelope at the decanter temperature. The process feasibility analysis is validated by using rigorous simulation with the batch process simulator ProSimBatch. Simulation results are then corroborated in a bench experimental column for the selected entrainer, showing several advantages of heterogeneous batch distillation compared to homogeneous systems