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1,531 results on '"Williams, R. S."'

1. Optical Metamaterials at Near and Mid IR Range Fabricated by Nanoimprint Lithography

Author

Wu, W., Kim, E., Ponizovskaya, E., Liu, Y., Yu, Z., Fang, N., Shen, Y. R., Bratkovsky, A. M., Tong, W., Sun, C., Zhang, X., Wang, S. -Y., and Williams, R. S.

Subjects
Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

Two types of optical metamaterials operating at near-IR and mid-IR frequencies, respectively, have been designed, fabricated by nanoimprint lithography (NIL), and characterized by laser spectroscopic ellipsometry. The structure for the near-IR range was a metal/dielectric/metal stack "fishnet" structure that demonstrated negative permittivity and permeability in the same frequency region and hence exhibited a negative refractive index at a wavelength near 1.7 um. In the mid-IR range, the metamaterial was an ordered array of four-fold symmetric L-shaped resonators (LSRs) that showed both a dipole plasmon resonance resulting in negative permittivity and a magnetic resonance with negative permeability near wavelengths of 3.7 um and 5.25 um, respectively. The optical properties of both metamaterials are in agreement with theoretical predictions. This work demonstrates the feasibility of designing various optical negative-index metamaterials and fabricating them using the nanoimprint lithography as a low-cost, high-throughput fabrication approach., Comment: 25 pages, 12 figures

Published
2006
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2. Bistable molecular conductors with a field-switchable dipole group

Author

Kornilovitch, P. E., Bratkovsky, A. M., and Williams, R. S.

Subjects
Condensed Matter - Soft Condensed Matter
Abstract

A class of bistable "stator-rotor" molecules is proposed, where a stationary bridge (stator) connects the two electrodes and facilitates electron transport between them. The rotor part, which has a large dipole moment, is attached to an atom of the stator via a single sigma bond. Hydrogen bonds formed between the rotor and stator make the symmetric orientation of the dipole unstable. The rotor has two potential minima with equal energy for rotation about the sigma bond. The dipole orientation, which determines the conduction state of the molecule, can be switched by an external electric field that changes the relative energy of the two potential minima. Both orientation of the rotor correspond to asymmetric current-voltage characteristics that are the reverse of each other, so they are distinguishable electrically. Such bistable stator-rotor molecules could potentially be used as parts of molecular electronic devices., Comment: 8 pages, 7 figures

Published
2002
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3. Current rectification by molecules with asymmetric tunneling barriers

Author

Kornilovitch, P. E., Bratkovsky, A. M., and Williams, R. S.

Subjects
Condensed Matter - Soft Condensed Matter, Condensed Matter - Materials Science
Abstract

A simple experimentally accessible realization of current rectification by molecules (molecular films) bridging metal electrodes is described. It is based on the spatial asymmetry of the molecule and requires only one resonant conducting molecular level (pi-orbital). The rectification, which is due to asymmetric coupling of the level to the electrodes by tunnel barriers, is largely independent of the work function difference between the two electrodes. Results of extensive numerical studies of the family of suggested molecular rectifiers HS-(CH2)_m-C6H4-(CH2)_n-SH are presented. The highest rectification ratio ~500 is achieved at m = 2 and n = 10., Comment: 12 pages, 10 figures; figures 2 and 3 now included in the text

Published
2002
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4. Bi-stable tunneling current through a molecular quantum dot

Author

Alexandrov, A. S., Bratkovsky, A. M., and Williams, R. S.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Strongly Correlated Electrons
Abstract

An exact solution is presented for tunneling through a negative-U d-fold degenerate molecular quantum dot weakly coupled to electrical leads. The tunnel current exhibits hysteresis if the level degeneracy of the negative-U dot is larger than two (d>2). Switching occurs in the voltage range V1 < V < V2 as a result of attractive electron correlations in the molecule, which open up a new conducting channel when the voltage is above the threshold bias voltage V2. Once this current has been established, the extra channel remains open as the voltage is reduced down to the lower threshold voltage V1. Possible realizations of the bi-stable molecular quantum dots are fullerenes, especially C60, and mixed-valence compounds., Comment: 5 pages, 1 figure. (v2) Figure updated to compare the current hysteresis for degeneracies d=4 and d>>1 of the level in the dot, minor corrections in the text. To appear in Phys. Rev. B

Published
2002
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10. Unifying Science and Education

Author

Akins, Daniel L., Bar-Yam, Yaneer, Batterson, James G., Cohen, Avis H., Gorman, Michael E., Heller, M., Klein-Seetharaman, Judith, Pope, Alan T., Roco, M. C., Reddy, Raj, Tolles, W. M., Williams, R. S., Zolandz, D., Roco, Mihail C., editor, and Bainbridge, William Sims, editor

Published
2003
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41. James Franklin Collins correspondence

Author

Collins, J. Franklin (James Franklin), 1863-1940, Underwood, Lucien Marcus, 1853-1907, Vasey, George, 1822-1893, Warner, Edith A., Warnstorf, Carl, 1837-1921, Watson, Sereno, 1826-1892, Weatherby, Charles Alfred, 1875-1949, Webber, George C., Webber, Martha J., Webster, Hollis, 1862-1943, Weg, Max, Weigel, Oswald, Wendte, William, 1877-1904, Wetherby, Albert G., Wheeler, Harriet, Whipple, Edward Everett, Whipple, F. M., White, Mary B., Whittemore, George Francis, Williams, Blanche E. Wheeler, Williams, Emile Francis, 1858-1929, Williams, R. S. (Robert Statham), 1859-1945, Wilson, A. B., Mrs, Wilson, Clarence E., Wilson, Ernest Henry, 1876-1930, Zerschwitz, Friedrich von, Harvard University Botany Libraries, Collins, J. Franklin (James Franklin), 1863-1940, Underwood, Lucien Marcus, 1853-1907, Vasey, George, 1822-1893, Warner, Edith A., Warnstorf, Carl, 1837-1921, Watson, Sereno, 1826-1892, Weatherby, Charles Alfred, 1875-1949, Webber, George C., Webber, Martha J., Webster, Hollis, 1862-1943, Weg, Max, Weigel, Oswald, Wendte, William, 1877-1904, Wetherby, Albert G., Wheeler, Harriet, Whipple, Edward Everett, Whipple, F. M., White, Mary B., Whittemore, George Francis, Williams, Blanche E. Wheeler, Williams, Emile Francis, 1858-1929, Williams, R. S. (Robert Statham), 1859-1945, Wilson, A. B., Mrs, Wilson, Clarence E., Wilson, Ernest Henry, 1876-1930, and Zerschwitz, Friedrich von

Subjects
(James Franklin), Botanists, Business cards, Collins, J. Franklin, Correspondence, Postcards, Receipts (financial records), Sketch maps
Published
1884

42. Plant list : Bolivia,

Author

Williams, R. S. 1859-1945, Harvard University Botany Libraries, and Williams, R. S. 1859-1945

Subjects
Bolivia, Plants
Published
1901

43. Walter Deane correspondence

Author

Bailey, L. H. (Liberty Hyde), 1858-1954, Bebb, M. S. (Michael Schuck), 1833-1895, Blaschka, Rudolf, 1857-1939, Deane, Walter, 1848-1930, Lloyd, C. G. (Curtis Gates), 1859-1926, Morong, Thomas, Owen, Maria L. (Maria Louisa), 1825-1913, Rose, J. N. (Joseph Nelson), 1862-1928, Allen, Glover M. (Glover Morrill), 1879-1942, Audubon, Florence, Audubon, Maria R. (Maria Rebecca), 1843-1925, Bailey, Eliza R., Barnes, Charles Reid, 1858-1910, Batchelder, Annie V., Batchelder, Charles Foster, 1856-1954, Benson, Albert Emerson, 1870, Brainerd, Ezra, 1844-1924, Brewster, William, 1851-1919, Carr, Albert Bonus, Carr, Gladys V., Chase, Agnes, 1869-1963, Cheney, Robert F., Christensen, Abby W., Churchill, Joseph Richmond, 1845-1933, Coolidge, Charles Austin, 1844, Curtiss, Allen Hiram, 1845-1907, Cushing, Mary, Deane, Charles E., Demetrio, C. H. (Charles Hermann), 1845-1936, Dexter, Lucy W., Dexter, Mary, 1886, Eames, Edwin Hubert, 1865-1948, Eaton, A. A. (Alvah Augustus), 1865-1908, Eggleston, W. W. (Willard Webster), 1863-1935, Faber, Helen R., Faber, Richard R., Farlow, W. G. (William Gilson), 1844-1919, Farwell, Oliver Atkins, 1867-1944, Faxon, Edwin, 1823-1898, Fernald, George B., Fernald, Merritt Lyndon, 1873-1950, Foord, William M., Foster, Theodore B., Ganong, William Francis, 1864-1941, Gattinger, Augustin, 1825-1903, Glatfelter, Noah Miller, 1837-1911, Goodale, George L. (George Lincoln), 1839-1923, Greene, Edward Lee, 1843-1915, Greenman, Anne T., Greenman, J. M. (Jesse More), 1867-1951, Hay, G. U. (George Upham), 1843-1912, Heading, Alice J., Herriot, W., Hervey, E. W. (Eliphalet Williams), 1834-1925, Hill, E. J. (Ellsworth Jerome), 1833-1917, Hitchcock, A. S. (Albert Spear), 1865-1935, Holm, Theodor (Herman Theodor), 1854-1932, Hopkins, Richard J., Huber, Lucretia M., Jesup, Henry G. (Henry Griswold), 1826-1903, Kennedy, George G. (George Golding), 1841-1918, Knowlton, Frank Hall, 1860-1926, Lamson-Scribner, F., Linder, Charles, Lowell, James Arnold, Lunell, J. (Joel), 1851-1920, Mathews, F. Schuyler (Ferdinand Schuyler), 1854-1938, Maxon, William R. (William Ralph), 1877-1948, McAtee, W. L. (Waldo Lee) 1883-1962, Meehan, Thomas, 1826-1901, Munter, William H., Oldys, Henry, Paton, Lucy Allen, Pease, Arthur Stanley, 1881-1964, Peebles, Florence 1874, Peebles, Florence, 1874-1956, Penhallow, D. P. (David Pearce), 1854-1910, Pennock, Charles J., Philbrook, Augustus E., Porter, Thomas C. (Thomas Conrad), 1822-1901, Pringle, Cyrus G. (Cyrus Guernsey), 1838-1911, Putnam, Bessie Lucina, Putnam, William T., Rand, Edward L. (Edward Lothrop), 1859-1924, Rau, Eugene A. (Eugene Abraham), 1848-1932, Rehder, Alfred, 1863-1949, Richardson, Martha Bebb, Robinson, Benjamin Lincoln, 1864-1935, Rolfe, W. J. 1827-1910, Sandberg, John Herman, 1848-1917, Scudder, Winthrop S., Sheppard, Susan, Shute, Fred A., Spaulding, F. B., Sprague, A. C., Steere, Rebecca P., Stone, Phoebe J., Stowell, Ruth K., Suksdorf, Wilhelm, 1850-1932, Tatnall, Edward, 1898, Terry, Emily Hitchcock, 1838-1921, Thaxter, Roland, 1858-1932, Thayer, Evelyn, Thayer, John Eliot, 1862-1933, Townsend, Charles Wendell, 1859-1934, Underwood, Lucien Marcus, 1853-1907, Vasey, George, 1822-1893, Ward, Lester F. (Lester Frank), 1841-1913, Ware, Robert Allison, Weatherby, Charles Alfred, 1875-1949, Wiegand, K. M. (Karl McKay), 1873-1942, Williams, Emile Francis, 1858-1929, Williams, R. S. (Robert Statham), 1859-1945, Wood, Casey A. (Casey Albert), 1856-1942, Woodhouse, S. W. (Samuel Washington), 1821-1904, Harvard University. Gray Herbarium, Harvard University Botany Libraries, Bailey, L. H. (Liberty Hyde), 1858-1954, Bebb, M. S. (Michael Schuck), 1833-1895, Blaschka, Rudolf, 1857-1939, Deane, Walter, 1848-1930, Lloyd, C. G. (Curtis Gates), 1859-1926, Morong, Thomas, Owen, Maria L. (Maria Louisa), 1825-1913, Rose, J. N. (Joseph Nelson), 1862-1928, Allen, Glover M. (Glover Morrill), 1879-1942, Audubon, Florence, Audubon, Maria R. (Maria Rebecca), 1843-1925, Bailey, Eliza R., Barnes, Charles Reid, 1858-1910, Batchelder, Annie V., Batchelder, Charles Foster, 1856-1954, Benson, Albert Emerson, 1870, Brainerd, Ezra, 1844-1924, Brewster, William, 1851-1919, Carr, Albert Bonus, Carr, Gladys V., Chase, Agnes, 1869-1963, Cheney, Robert F., Christensen, Abby W., Churchill, Joseph Richmond, 1845-1933, Coolidge, Charles Austin, 1844, Curtiss, Allen Hiram, 1845-1907, Cushing, Mary, Deane, Charles E., Demetrio, C. H. (Charles Hermann), 1845-1936, Dexter, Lucy W., Dexter, Mary, 1886, Eames, Edwin Hubert, 1865-1948, Eaton, A. A. (Alvah Augustus), 1865-1908, Eggleston, W. W. (Willard Webster), 1863-1935, Faber, Helen R., Faber, Richard R., Farlow, W. G. (William Gilson), 1844-1919, Farwell, Oliver Atkins, 1867-1944, Faxon, Edwin, 1823-1898, Fernald, George B., Fernald, Merritt Lyndon, 1873-1950, Foord, William M., Foster, Theodore B., Ganong, William Francis, 1864-1941, Gattinger, Augustin, 1825-1903, Glatfelter, Noah Miller, 1837-1911, Goodale, George L. (George Lincoln), 1839-1923, Greene, Edward Lee, 1843-1915, Greenman, Anne T., Greenman, J. M. (Jesse More), 1867-1951, Hay, G. U. (George Upham), 1843-1912, Heading, Alice J., Herriot, W., Hervey, E. W. (Eliphalet Williams), 1834-1925, Hill, E. J. (Ellsworth Jerome), 1833-1917, Hitchcock, A. S. (Albert Spear), 1865-1935, Holm, Theodor (Herman Theodor), 1854-1932, Hopkins, Richard J., Huber, Lucretia M., Jesup, Henry G. (Henry Griswold), 1826-1903, Kennedy, George G. (George Golding), 1841-1918, Knowlton, Frank Hall, 1860-1926, Lamson-Scribner, F., Linder, Charles, Lowell, James Arnold, Lunell, J. (Joel), 1851-1920, Mathews, F. Schuyler (Ferdinand Schuyler), 1854-1938, Maxon, William R. (William Ralph), 1877-1948, McAtee, W. L. (Waldo Lee) 1883-1962, Meehan, Thomas, 1826-1901, Munter, William H., Oldys, Henry, Paton, Lucy Allen, Pease, Arthur Stanley, 1881-1964, Peebles, Florence 1874, Peebles, Florence, 1874-1956, Penhallow, D. P. (David Pearce), 1854-1910, Pennock, Charles J., Philbrook, Augustus E., Porter, Thomas C. (Thomas Conrad), 1822-1901, Pringle, Cyrus G. (Cyrus Guernsey), 1838-1911, Putnam, Bessie Lucina, Putnam, William T., Rand, Edward L. (Edward Lothrop), 1859-1924, Rau, Eugene A. (Eugene Abraham), 1848-1932, Rehder, Alfred, 1863-1949, Richardson, Martha Bebb, Robinson, Benjamin Lincoln, 1864-1935, Rolfe, W. J. 1827-1910, Sandberg, John Herman, 1848-1917, Scudder, Winthrop S., Sheppard, Susan, Shute, Fred A., Spaulding, F. B., Sprague, A. C., Steere, Rebecca P., Stone, Phoebe J., Stowell, Ruth K., Suksdorf, Wilhelm, 1850-1932, Tatnall, Edward, 1898, Terry, Emily Hitchcock, 1838-1921, Thaxter, Roland, 1858-1932, Thayer, Evelyn, Thayer, John Eliot, 1862-1933, Townsend, Charles Wendell, 1859-1934, Underwood, Lucien Marcus, 1853-1907, Vasey, George, 1822-1893, Ward, Lester F. (Lester Frank), 1841-1913, Ware, Robert Allison, Weatherby, Charles Alfred, 1875-1949, Wiegand, K. M. (Karl McKay), 1873-1942, Williams, Emile Francis, 1858-1929, Williams, R. S. (Robert Statham), 1859-1945, Wood, Casey A. (Casey Albert), 1856-1942, Woodhouse, S. W. (Samuel Washington), 1821-1904, and Harvard University. Gray Herbarium

Subjects
Albumen prints, Black-and-white photographs, Botanists, Clippings (information artifacts), Correspondence, Deane, Walter, Picture postcards, Postcards, Specimens
Published
1889

44. Contributions to the botany of the Yukon Territory, by Marshall A. Howe [and ohters]

Author

Britton, Nathaniel Lord, 1859-1934, Howe, Marshall A. 1867-1936, Rydberg, Per Axel, 1860-1931, Underwood, Lucien Marcus, 1853-1907, Williams, R. S. 1859-1945, New York Botanical Garden, LuEsther T. Mertz Library, Britton, Nathaniel Lord, 1859-1934, Howe, Marshall A. 1867-1936, Rydberg, Per Axel, 1860-1931, Underwood, Lucien Marcus, 1853-1907, and Williams, R. S. 1859-1945

Subjects
Plants, Yukon Territory
Published
1901

45. Contributions to the botany of the Yukon Territory

Author

Britton, Nathaniel Lord, 1859-1934, Howe, Marshall A. (Marshall Avery), 1867-1936, Rydberg, Per Axel, 1860-1931, Underwood, Lucien Marcus, 1853-1907, Williams, R. S. (Robert Statham), 1859-1945, New York Botanical Garden, LuEsther T. Mertz Library, Britton, Nathaniel Lord, 1859-1934, Howe, Marshall A. (Marshall Avery), 1867-1936, Rydberg, Per Axel, 1860-1931, Underwood, Lucien Marcus, 1853-1907, and Williams, R. S. (Robert Statham), 1859-1945

Subjects
Plants, Yukon Territory

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