Orientation filtering by growth-velocity competition in zone-melting recrystallization of silicon on SiO_2

We describe a method of controlling the in-plane directions of grains in (100)-textured silicon films produced by zone-melting recrystallization over amorphous SiO2. Grains having in-plane orientation within a narrow range are able to grow through an orientation filter consisting of a pattern of crystallization barriers, while grains having other orientations are occluded. The results of experiments using an orientation filter, and the parameters which optimize filter performance, are reported

X-ray lithography masking

X-ray masking apparatus includes a frame having a supporting rim surrounding an x-ray transparent region, a thin membrane of hard inorganic x-ray transparent material attached at its periphery to the supporting rim covering the x-ray transparent region and a layer of x-ray opaque material on the thin membrane inside the x-ray transparent region arranged in a pattern to selectively transmit x-ray energy entering the x-ray transparent region through the membrane to a predetermined image plane separated from the layer by the thin membrane. A method of making the masking apparatus includes depositing back and front layers of hard inorganic x-ray transparent material on front and back surfaces of a substrate, depositing back and front layers of reinforcing material on the back and front layers, respectively, of the hard inorganic x-ray transparent material, removing the material including at least a portion of the substrate and the back layers of an inside region adjacent to the front layer of hard inorganic x-ray transparent material, removing a portion of the front layer of reinforcing material opposite the inside region to expose the surface of the front layer of hard inorganic x-ray transparent material separated from the inside region by the latter front layer, and depositing a layer of x-ray opaque material on the surface of the latter front layer adjacent to the inside region

Inverse Design of High-NA Metalens for Maskless Lithography

We demonstrate an axisymmetric inverse-designed metalens to improve the performance of zone-plate-array lithography (ZPAL), one of the maskless lithography approaches, that offer a new paradigm for nanoscale research and industry. First, we derive a computational upper bound for a unit-cell-based axisymmetric metalens. Then, we demonstrate a fabrication-compatible inverse-designed metalens with 85.50\% transmission normalized focusing efficiency at 0.6 numerical aperture at 405nm wavelength; a higher efficiency than a theoretical gradient index lens design (79.98\%). We also demonstrate experimental validation for our axisymmetric inverse-designed metalens via electron beam lithography. Metalens-based maskless lithography may open a new way of achieving low-cost, large-area nanofabrication

High-Speed Maskless Photolithography for Customized Nanomanufacturing

Achieving high functionality in nanoscale assemblies will require means of deterministically introducing structural complexity. Lithography represents the most effective technology currently at our disposal for creating such structural complexity. In research and in nanomanufacturing, flexibility as well as reasonable throughput and high resolution, are required. For lithographic patterning, photons have numerous advantages over charged particles. Even the disadvantage of lower resolution may soon be circumvented. The maskless photolithography system under development at LumArray Inc., and our plans for future extensions to the deep sub-100nm domain, will be described

Novel Superconducting Tunneling Structures

Contains a description of one research project.Joint Services Electronics Program Contract DAAL03-89-C-000

Media exposure, behavioural risk factors and HIV testing among women of reproductive age in Papua New Guinea: a cross-sectional study

Background: Reproductive health remains a major health concern in developing countries such as Papua New Guinea (PNG). The prevalence of human immunodeficiency virus (HIV) in PNG is the highest in the Southern Pacific region, with women having a higher risk of contracting the infection. Hence, there have been several policies aimed at mitigating the spread of the disease. One of these policies include the use of mass media as a health promotion tool to educate the population on the risk of the disease. Therefore, this study aimed at investigating the association of mass media to HIV testing among women. Methods: Data were obtained from the PNG Demographic and Health Survey (DHS) of 2019. A total of 15,005 reproductive-age women was included in this analysis. Results: The results showed that women with low (aOR = 1.63, 95% CI: 1.39, 1.90) and high (aOR = 1.53, 95% CI: 1.36, 1.72) media exposure were more likely to undertake HIV testing compared to those with no media exposure. Compared to no education, women with incomplete primary (aOR = 1.22, 95% CI: 1.06, 1.40), complete primary (aOR = 1.56, 95% CI: 1.30, 1.87), incomplete secondary (aOR = 2.18, 95% CI: 1.85, 2.58), complete secondary (aOR= 2.33, 95% CI: 1.77, 3.09) and higher (aOR = 3.38, 95% CI: 2.57, 4.46) education were more likely to undertake HIV testing. Compared to women with the poorest wealth index, women with richer indexes were more likely to undertake HIV testing. Women living in rural areas were less likely to undertake HIV testing (aOR = 0.72, 95% CI: 0.63, 0.82). However, marital status, knowledge of transmission and religion were not associated with HIV testing. Conclusion: In conclusion, this study provides strong evidence that mass media exposure increases the likelihood of HIV testing in women of reproductive age in PNG. Mass media campaigns would serve as a cost-effective health promotion tool against the spread of disease

Single-Electron Spectroscopy

Contains an introduction, reports on four research projects and a list of publications,Joint Services Electronics Program Grant DAAH04-95-1-0038National Science Foundation Young Investigator AwardU.S. Navy - Office of Naval Research Grant N00014-93-1-063

Cyclic, disulfide- and dithioether-containing opioid tetrapeptides: Development of a ligard with high delta opioid receptor selectivity and affinity

Tetrapeptides of primary sequence Tyr-X-Phe-YNH2, where X is D-Cys or D-Pen (penicillamine) and where Y is D-Pen or L-Pen, were prepared and were cyclized via the side chain sulfurs of residues 2 and 4 to disulfide or dithioether-containing analogs. These peptides are related to previously reported penicillamine-containing pentapeptide enkephalin analogs but lack the central glycine residue of the latter and were designed to assess the effect of decreased ring size on opioid activity. Binding affinities of the tetrapeptides were determined to both [mu] and [delta] opioid receptors. Binding affinity and selectivity in the tetrapeptide series were observed to be highly dependent on primary sequence. For example, L-Pen4 analogs displayed low affinity and were nonselective, while the corresponding D-Pen4 diastereomers were of variable affinity and higher selectivity. Among the latter compounds were examples of potent analogs in which selectivity shifted from [delta] selective to [mu] selective as the ring size was increased. The relatively high binding affinity and [delta] receptor selectivity observed with one of the carboxamide terminal disulfide analogs led to the synthesis of the corresponding carboxylic acid terminal, Tyr-D-Cys-Phe-D-PenOH. This analog displayed [delta] receptor binding selectivity similar to that of the standard [delta] ligand, [D-Pen2, D-Pen5] enkephalin (DPDPE), and was found to have a 3.5-fold higher binding affinity than DPDPE. All the tetrapeptides were further evaluated in the isolated mouse vas deferens (mvd) assay and all displayed opioid agonist activity. In general, tetrapeptide potencies in the mouse vas deferens correlated well with binding affinities but were somewhat lower. Receptor selectivity in the mvd, assessed by examining the effect of opioid antagonists on the tetrapeptide concentration-effect curves, was similar to that determined in the binding studies.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27602/1/0000646.pd