Technique for producing bipolar and MOS field effect transistors on a single chip

Several cycles of photoetching, dopant deposition, and drive-in produce selectively-doped regions and semiconductor junctions within a single chip

An evaluation of errors observed in the measurement of low wind velocities

Measurements of low wind velocities (the absolute value of V sub H is approx. equal to 6 m/s) with a VHF wind profiler can be difficult if ground clutter or other biases in the system dominate in altering the position of the perceived peak in the calculated power spectrum. A variety of methods for ground clutter suppression are used in profiler systems today (Cornish, 1983). An editing method called zero suppression takes the spectral value of selectable number of points (N) on each side of 0 velocity (one point on either side, in this study) and sets them equal to the mean value of the points exterior to the specified N points on either side of 0. Analysis done with the PSU VHF(1) radar, shows that this zero-suppression method can systematically bias horizontal wings V sub H below 6 m/s. With the zero suppression, an artificial increase in absolute wind velocities occurs when the spectral peaks fall within the plus or minus N points of the FFT (personal communication, Strauch, 1985). It was also established that the method artificially decreases the absolute wind velocities inferred from spectral peaks that are outside but near the suppressed region. Comparisons of wind profiles observed with and without zero suppression are given. The range of the biased velocities extends to about plus or minus 6 m/s. Biases have been deduced to be as much as 2 m/s, but more commonly they are on the order of 1.0 m/s

Coupling of phonons to a helium atom adsorbed on graphite

We compute the self-energy for a ^4He atom adsorbed on graphite to second order in the phonon coupling. The phonon contributions amount to several degrees Kelvin. The imaginary part corresponds to a lifetime of some 10^(-11) s

Black Male Student-Athletes and Racial Inequities in NCAA Division I College Sports

The purpose of this report is to make transparent racial inequities in NCAA Division I college sports. Specifically, the authors offer a four-year analysis of Black men's representation on football and basketball teams versus their representation in the undergraduate student body on each campus. The report concludes with recommendations for the NCAA and commissioners of the six major sports conferences, college and university leaders, coaches and athletics directors, journalists, and Black male student-athletes and their families

Measurements of the extinction parameters of hot seeded hydrogen at high pressures

Measurement of extinction parameter of tungsten-hydrogen aerosols as function of wavelength at high pressures and temperature

Correlation length of hydrophobic polyelectrolyte solutions

The combination of two techniques (Small Angle X-ray Scattering and Atomic Force Microscopy) has allowed us to measure in reciprocal and real space the correlation length $\xi$ of salt-free aqueous solutions of highly charged hydrophobic polyelectrolyte as a function of the polymer concentration $C_p$, charge fraction $f$ and chain length $N$. Contrary to the classical behaviour of hydrophilic polyelectrolytes in the strong coupling limit, $\xi$ is strongly dependent on $f$. In particular a continuous transition has been observed from $\xi \sim C_p^{-1/2}$ to $\xi\sim C_p^{-1/3}$ when $f$ decreased from 100% to 35%. We interpret this unusual behaviour as the consequence of the two features characterising the hydrophobic polyelectrolytes: the pearl necklace conformation of the chains and the anomalously strong reduction of the effective charge fraction.Comment: 7 pages, 5 figures, submitted to Europhysics Letter

The Effect of Transfer Printing on Pentacene Thin-Film Crystal Structure

The thermal deposition and transfer Printing method had been used to produce pentacene thin-films on SiO2/Si and plastic substrates (PMMA and PVP), respectively. X-ray diffraction patterns of pentacene thin films showed reflections associated with highly ordered polycrystalline films and a coexistence of two polymorph phases classified by their d-spacing, d(001): 14.4 and 15.4 A.The dependence of the c-axis correlation length and the phase fraction on the film thickness and printing temperature were measured. A transition from the 15.4 A phase towards 14.4 A phase was also observed with increasing film thickness. An increase in the c-axis correlation length of approximately 12% ~16% was observed for Pn films transfer printed onto a PMMA coated PET substrate at 100~120 C as compared to as-grown Pn films on SiO2/Si substrates. The transfer printing method is shown to be an attractive for the fabrication of pentacene thin-film transistors on flexible substrates partly because of the resulting improvement in the quality of the pentacene film.Comment: 5 pages, 5 figure

The clumpiness of molecular clouds: HCO+ (3--2) survey near Herbig-Haro objects

Some well-studied Herbig Haro objects have associated with them one or more cold, dense, and quiescent clumps of gas. We propose that such clumps near an HH object can be used as a general measure of clumpiness in the molecular cloud that contains that HH object. Our aim is to make a survey of clumps around a sample of HH objects, and to use the results to make an estimate of the clumpiness in molecular clouds. All known cold, dense, and quiescent clumps near HH objects are anomalously strong HCO+ emitters. Our method is, therefore, to search for strong HCO+ emission as an indicator of a clump near to an HH object. The searches were made using JCMT and SEST in the HCO+ 3-2 and also H13CO+ 1-0 lines, with some additional searches for methanol and sulphur monoxide lines. The sources selected were a sample of 22 HH objects in which no previous HCO+ emission had been detected. We find that half of the HH objects have clumps detected in the HCO+ 3-2 line and that all searches in H13CO$+ 1-0 lines show evidence of clumpiness. All condensations have narrow linewidths and are evidently unaffected dynamically by the HH jet shock. We conclude that the molecular clouds in which these HH objects are found must be highly heterogeneous on scales of less than 0.1 pc. An approximate calculation based on these results suggests that the area filling factor of clumps affected by HH objects is on the order of 10%. These clumps have gas number densities larger than 3e4 cm-2.Comment: 11 pages, 14 figures. Accepted for publication in Astronomy and Astrophysic

Effectiveness of zinc supplementation on diarrhea and average daily gain in pre-weaned dairy calves: A double-blind, block-randomized, placebo-controlled clinical trial.

The objective of this clinical trial was to evaluate the effectiveness of zinc supplementation on diarrhea and average daily weight gain (ADG) in pre-weaned dairy calves. A total of 1,482 healthy Holstein heifer and bull calves from a large California dairy were enrolled at 24 to 48 hours of age until hutch exit at approximately 90 days of age. Calves were block-randomized by time to one of three treatments: 1) placebo, 2) zinc methionine (ZM), or 3) zinc sulfate (ZS) administered in milk once daily for 14 days. Serum total protein at enrollment and body weight at birth, treatment end, and hutch exit were measured. Fecal consistency was assessed daily for 28 days post-enrollment. For a random sample of 127 calves, serum zinc concentrations before and after treatment and a fecal antigen ELISA at diarrhea start and resolution for Escherichia coli K99, rotavirus, coronavirus, and Cryptosporidium parvum were performed. Linear regression showed that ZM-treated bull calves had 22 g increased ADG compared to placebo-treated bulls (P = 0.042). ZM-treated heifers had 9 g decreased ADG compared to placebo-treated heifers (P = 0.037), after adjusting for average birth weight. Sex-stratified models showed that high birth weight heifers treated with ZM gained more than placebo-treated heifers of the same birth weight, which suggests a dose-response effect rather than a true sex-specific effect of ZM on ADG. Cox regression showed that ZM and ZS-treated calves had a 14.7% (P = 0.015) and 13.9% (P = 0.022) reduced hazard of diarrhea, respectively, compared to placebo-treated calves. Calves supplemented for at least the first five days of diarrhea with ZM and ZS had a 21.4% (P = 0.027) and 13.0% (P = 0.040) increased hazard of cure from diarrhea, respectively, compared to placebo-treated calves. Logistic regression showed that the odds of microbiological cure at diarrhea resolution for rotavirus, C. parvum, or any single fecal pathogen was not different between treatment groups. Zinc supplementation delayed diarrhea and expedited diarrhea recovery in pre-weaned calves. Additionally, zinc improved weight gain differentially in bulls compared to heifers, indicating a research need for sex-specific dosing

Atmospheric chemistry of gas-phase polycyclic aromatic hydrocarbons: formation of atmospheric mutagens.

The atmospheric chemistry of the 2- to 4-ring polycyclic aromatic hydrocarbons (PAH), which exist mainly in the gas phase in the atmosphere, is discussed. The dominant loss process for the gas-phase PAH is by reaction with the hydroxyl radical, resulting in calculated lifetimes in the atmosphere of generally less than one day. The hydroxyl (OH) radical-initiated reactions and nitrate (NO3) radical-initiated reactions often lead to the formation of mutagenic nitro-PAH and other nitropolycyclic aromatic compounds, including nitrodibenzopyranones. These atmospheric reactions have a significant effect on ambient mutagenic activity, indicating that health risk assessments of combustion emissions should include atmospheric transformation products