1,025 research outputs found
Joshua D. Dorsey's Quick Files
No full textThe Quick Files feature was discontinued and it’s files were migrated into this Project on March 11, 2022. The file URL’s will still resolve properly, and the Quick Files logs are available in the Project’s Recent Activity
Joshua D. Dorsey's Quick Files
No full textThe Quick Files feature was discontinued and it’s files were migrated into this Project on March 11, 2022. The file URL’s will still resolve properly, and the Quick Files logs are available in the Project’s Recent Activity
Joshua D. Dorsey's Quick Files
No full textThe Quick Files feature was discontinued and it’s files were migrated into this Project on March 11, 2022. The file URL’s will still resolve properly, and the Quick Files logs are available in the Project’s Recent Activity
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Geologic map of the Dufur area, Wasco County, Oregon
No full textReport -- Plate 1 -- Plate 2 -- Plate 3.Jason D. McClaughry, Heather H. Herinckx, Clark A. Niewendorp, Carlie J.M. Azzopardi, and Joshua A. Hackett.Title from PDF cover (viewed on May 19, 2021).This archived document is maintained by the State Library of Oregon as part of the Oregon Documents Depository Program. It is for informational purposes and may not be suitable for legal purposes.Includes bibliographical references.Mode of access: Internet from the Oregon Government Publications Collection.Text in English
Design of a high quality factor spiral inductors in RF MCM-D
No full textThesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 79-82).This thesis studies the design and fabrication of spiral inductors for use in Radio Frequency (RF) applications. A design methodology is developed to search an inductor design space efficiently using existing simulation software. The methodology allows designers to specify a desired inductance, total area, and frequency of operation instead of the geometrical parameters required by most design software. An implementation of the methodology that finds devices with optimal quality factor at a given frequency is presented. Several inductor designs are generated using this implementation, and the devices are fabricated in the Draper Laboratory, Inc. Multichip Module-Deposited (MCM-D) process. Simulated characteristics of the devices are verified using experimental measurements, and deviations from predicted performance are discussed.by Joshua Peters.M.Eng
Intramolecular [2 + 2] Cycloaddition Reactions of Allene-ynes: Exploring the Scope, Mechanism, and Application to the Synthesis of Carbocyclic Spirooxindoles
No full textThe thermal allene-yne [2 + 2] cycloaddition reaction provides quick and efficient access to alkylidene cyclobutene compounds containing a fused bicyclic ring structure. The mechanism of this reaction was examined computationally in collaboration with Dean Tantillo and Matthew Siebert and experimentally in our lab. Computational studies suggest that the allene-yne [2 + 2] cycloaddition reaction proceeds via a stepwise diradical pathway. It is commonplace for researchers to postulate diradical intermediates for thermally disallowed cycloaddition reactions, but rarely are experiments conducted to support their existence. Experimental efforts to trap the postulated diradical intermediate included appending a cyclopropane to various allene-yne substrates. In two examples, products resulting from cyclopropane ring opening were isolated and characterized, thus providing experimental evidence supporting a diradical intermediate.
The scope of the thermal allene-yne [2 + 2] cycloaddition reaction was expanded to the preparation of spirocyclobutene oxindoles. Our investigation led to the discovery of a tandem thermal [3,3]-sigmatropic rearrangement/[2 + 2] cycloaddition reaction of propargyl esters to afford carbocyclic spirooxindoles. This methodology lent itself to the formation of both spirobicyclo[4.2.0]oxindoles and spirobicyclo[5.2.0]oxindoles in moderate yields. The scope of the reaction was expanded to the synthesis of potentially biologically active spirocyclobutene oxindole compounds.
Transfer of chirality from an allene to the [2 + 2] cycloadduct was possible when using a tert-butyl substituted allene; however in the case of a propargyl acetate substrate, complete racemization was observed during the tandem [3,3]-sigmatropic rearrangement/[2 + 2] cycloaddition reaction. We hypothesize that the bulkiness of the tert-butyl group and oxindole restricts rotation at the intermediate diradical and thus prevents racemization.
The synthetic utility of the resulting [2 + 2] cycloadducts was briefly examined. The most notable transformations were conversion of the enolacetate of the spirooxindole to the corresponding ketone and α-acetoxyketone
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