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297 results on '"Chen, F. R."'

1. Prospects for atomic resolution in-line holography for a 3D determination of atomic structures from single projections

Author

Chen, F-R, Kisielowski, C, and Van Dyck, D

Subjects
Chemical Sciences, Physical Sciences, Condensed Matter Physics, 3D molecular imaging, Atomic resolution tomography, Exit wave function, In-line holography
Abstract

It is now established that the 3D structure of homogeneous nanocrystals can be recovered from in-line hologram of single projections. The method builds on a quantitative contrast interpretation of electron exit wave functions. Since simulated exit wave functions of single and bilayers of graphene reveal the atomic structure of carbon-based materials with sufficient resolution, we explore theoretically how the approach can be expanded beyond periodic carbon-based materials to include non-periodic molecular structures. We show here theoretically that the 3D atomic structure of randomly oriented oleic acid molecules can be recovered from a single projection.

Published
2017

2. In-line three-dimensional holography of nanocrystalline objects at atomic resolution.

Author

Chen, F-R, Van Dyck, D, and Kisielowski, C

Abstract

Resolution and sensitivity of the latest generation aberration-corrected transmission electron microscopes allow the vast majority of single atoms to be imaged with sub-Ångstrom resolution and their locations determined in an image plane with a precision that exceeds the 1.9-pm wavelength of 300 kV electrons. Such unprecedented performance allows expansion of electron microscopic investigations with atomic resolution into the third dimension. Here we report a general tomographic method to recover the three-dimensional shape of a crystalline particle from high-resolution images of a single projection without the need for sample rotation. The method is compatible with low dose rate electron microscopy, which improves on signal quality, while minimizing electron beam-induced structure modifications even for small particles or surfaces. We apply it to germanium, gold and magnesium oxide particles, and achieve a depth resolution of 1-2 Å, which is smaller than inter-atomic distances.

Published
2016

3. Probing Catalyst Surfaces at the Atomic-scale

Author

Ek, M, primary, Hansen, L P, additional, Chen, F R, additional, van Dyck, D, additional, Kisielowski, C, additional, Specht, P, additional, Damsgaard, C D, additional, Jinschek, J R, additional, and Helveg, S, additional

Published
2023
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18. Satellite-Sensor Calibration Verification Using the Cloud-Shadow Method

Author

Reinersman, P, Carder, K. L, and Chen, F. R

Subjects
Earth Resources And Remote Sensing
Abstract

An atmospheric-correction method which uses cloud-shaded pixels together with pixels in a neighboring region of similar optical properties is described. This cloud-shadow method uses the difference between the total radiance values observed at the sensor for these two regions, thus removing the nearly identical atmospheric radiance contributions to the two signals (e.g. path radiance and Fresnel-reflected skylight). What remains is largely due to solar photons backscattered from beneath the sea to dominate the residual signal. Normalization by the direct solar irradiance reaching the sea surface and correction for some second-order effects provides the remote-sensing reflectance of the ocean at the location of the neighbor region, providing a known 'ground target' spectrum for use in testing the calibration of the sensor. A similar approach may be useful for land targets if horizontal homogeneity of scene reflectance exists about the shadow. Monte Carlo calculations have been used to correct for adjacency effects and to estimate the differences in the skylight reaching the shadowed and neighbor pixels.

Published
1995

22. Orbital susceptibilities of PbSe quantum dots.

Author

Jian, W. B., Weigang Lu, Jiye Fang, Chiang, S. J., Lan, M. D., Wu, C. Y., Wu, Z. Y., Chen, F. R., and Kai, J. J.

Subjects
QUANTUM dots, LEAD compounds, MAGNETIC susceptibility, SEMICONDUCTORS, LINEAR dependence (Mathematics), PHYSICAL & theoretical chemistry
Abstract

Different sizes of three-dimensional PbSe quantum dots have been synthesized for the study of orbital magnetic susceptibilities. Two types of orbital susceptibilities have been found, including the Curie susceptibility and finite-size corrections to the Landau susceptibility. The Curie term of a quantum dot manifests itself in the temperature dependence of magnetic susceptibility at low temperatures, while the field dependence of differential susceptibility at high temperatures shows finite-size corrections to the Landau susceptibility. Both of the two kinds of orbital susceptibility, estimated per quantum dot, show linear dependence on the size. [ABSTRACT FROM AUTHOR]

Published
2006
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23. Magnetoresistance of spin-dependent tunnel junctions with composite electrodes.

Author

Ho, C. H., Lin, Minn-Tsong, Yao, Y. D., Lee, S. F., Liao, C. C., Chen, F. R., and Kai, J. J.

Subjects
SEMICONDUCTOR junctions, MAGNETORESISTANCE, QUANTUM tunneling
Abstract

Spin-dependent tunnel junctions, Co/Al[sub 2]O[sub 3]/Co (CoFe)/NiFe, were fabricated to investigate the effect of the additional Co (CoFe) interlayer on tunneling magnetoresistance. The quality of the junction was examined with a cross-sectional image generated by high-resolution transmission electron microscopy, and an electron energy loss spectra map. For junctions with a Co (CoFe) interlayer in the top electrode thinner than 0.8 nm (1.0 nm), the tunneling magnetoresistance ratio increases with interlayer thickness. For junctions with a 0.8–2.0 nm Co (1.0–2.0 nm CoFe) interlayer in the top electrode, the tunneling magnetoresistance ratio reaches the maximum value of 2.16 (4.45) times that without any Co (CoFe) interlayer in the top electrode. The increase in the tunneling magnetoresistance ratio may be attributed to the increased effective ferromagnetic electrode polarization and the various spin-flip scattering factors. [ABSTRACT FROM AUTHOR]

Published
2001
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29. Atomic structure of Si/TbSi2/(111)Si double-heterostructure interfaces.

Author

Luo, C. H., Chen, F. R., and Chen, L. J.

Subjects
*INTERFACES (Physical sciences), *TRANSMISSION electron microscopy
Abstract

Deals with a study which analyzed the atomic structure of the Si/TbSi[sub2](111)Si double-heterostructure interfaces using high-resolution transmission electron microscopy. Experimental procedures; Coincident-site lattice models of interface structure; Conclusions.

Published
1994
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30. Optical study of strained ZnSe/GaAs and ZnMnSe/GaAs epilayers.

Author

Chou, W. C., Twardowski, A., Chern-Yu, K., Chen, F. R., Hua, C. R., Jonker, B. T., Yu, W. Y., Lee, S. T., Petrou, A., and Warnock, J.

Subjects
ZINC selenide, GALLIUM arsenide, REFLECTANCE, PHOTOLUMINESCENCE
Abstract

Details a study which examined strain-induced band splittings of zinc selinide/gallium arsenide and zinc[sub1-x] manganese[subx] selenium/gallium arsenide epilayers. Experimental problems; Reflectance spectra of the epilayers; Photoluminescence of the epilayers; Results and discussion.

Published
1994
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31. Evolution of vacancy ordering and defect structure in epitaxial YSi2-x thin films on (111)Si.

Author

Lee, T. L., Chen, L. J., and Chen, F. R.

Subjects
THIN films, SOLID state electronics, ELECTRON microscopy
Abstract

Presents information on a study that examined the evolution of vacancy ordering and defect structure in epitaxial YSi[sub2 x] thin films on silicon by both conventional and high-resolution transmission electron microscopy. Experimental procedures; Results and discussion on the study; Conclusions.

Published
1992
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36. Interface characterization and thermal stability of Co/Al–O/CoFe spin-dependent tunnel junctions.

Author

Lin, Minn-Tsong, Ho, C. H., Yao, Y. D., Huang, R. T., Liao, C. C., Chen, F. R., and Kai, J. J.

Subjects
INTERFACES (Physical sciences), TRANSMISSION electron microscopy
Abstract

A detailed study of the interface properties as well as the thermal stability has been done for the Co/Al-O/CoFe/NiFe magnetic tunnel junction, by using high resolution transmission electron microscopy equipped with energy dispersive x-ray spectrum. The Al behaves more stable against thermal annealing compared with the Fe, Co, Ni, and O elements. The reduction of the tunnel magnetoresistance ratio for the low annealing temperature (200 °C) may be caused by the spin flip scattering at oxide ion, rather than by the change in magnetic properties. The annealing at higher temperatures (300 °C and 400 °C) results in a strong interdiffusion, and in turn the disappearance of the magnetoresistance due to the shortcut of the junction. [ABSTRACT FROM AUTHOR]

Published
2002
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37. Effects of phase transformation and interdiffusion on the exchange bias of NiFe/NiMn.

Author

Lai, Chih-Huang, Lien, W. C., Chen, F. R., Kai, J. J., and Mao, S.

Subjects
SUPERLATTICES, PARAMAGNETISM, MAGNETIC properties
Abstract

The correlation between the exchange field of NiFe/NiMn and the phase transformation of NiMn was investigated. Transmission electron microscopy (TEM) dark-field images, contributed by the order phase of NiMn, were used to identify the location and volume fraction of the order phase. TEM selected area diffraction patterns showed the (110) superlattice diffraction rings of NiMn, verifying the existence of the order phase in the annealed samples. The order volume fraction can be calculated by the dark field image contributed by the (110) diffraction. The exchange field increased almost linearly with increasing order volume fraction. Energy dispersive x-ray spectroscopy attached to TEM indicated that Mn diffused into NiFe for annealing at 280 °C, leading to a larger coercivity and small coercivity squareness. Part of the NiMn still maintains the paramagnetic phase even after annealing at 280 °C. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Published
2001
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41. Extracting nano-gold from HAuCl4 solution manipulated with electrons.

Author

Lu, Y., Wang, K., Chen, F.-R., Zhang, W., and Sui, M. L.

Abstract

It has been fundamentally important and technologically challenging to elucidate the migration behavior of solute atoms in solvents, which can help to understand the growth of nanoparticles. Recently, ascribed to the booming development of start-of-the-art liquid environmental transmission electron microscopes (LETEMs), it has become possible to disclose, in situ, the phase segregation mechanism of elementary units in a solvent at the nanoscale. In addition, bombardment with an electron beam can induce a locally positive potential, with the application of low-conductive Si3N4 and water in LETEMs. Such merits can enable modification of the dynamic distribution and reductive behavior of the solute ions in water solutions. Herein we report the migration and segregation behaviors of Au atoms in a solvent during real time, by exploiting a charging effect in a dilute HAuCl4 water solution under electron irradiation. As a consequence, the growth kinetics of Au nanoparticles can be successfully controlled with an accelerated kinetics model. Through dynamically capturing the segregation behavior of the hydrated atoms, a resultant size-controlling mechanism is clarified with three cycles of nanoparticle growth behavior. A new insight is consequently gained into microscopically manipulating the hydrothermal synthesis of nanomaterials. [ABSTRACT FROM AUTHOR]

Published
2016
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45. A 1-D Simulation Analysis of the Development and Maintenance of the 2001 Red Tide of the Ichthyotoxic Dinoflagellate Karenia brevis on the West Florida Shelf

Author

NAVAL RESEARCH LAB STENNIS DETACHMENT STENNIS SPACE CENTER MS OCEANOGRAPHY DIV, Lenes, J M, Darrow, B P, Walsh, J J, Jolliff, J K, Chen, F R, Weisberg, R H, Zheng, L, NAVAL RESEARCH LAB STENNIS DETACHMENT STENNIS SPACE CENTER MS OCEANOGRAPHY DIV, Lenes, J M, Darrow, B P, Walsh, J J, Jolliff, J K, Chen, F R, Weisberg, R H, and Zheng, L

Abstract

A one-dimensional (1-D) ecological model, HABSIM, examined the initiation and maintenance of the 2001 red tide on the West Florida shelf (WFS). Phytoplankton competition among toxic dinoflagellates (Karenia brevis), nitrogen fixing cyanophytes (Trichodesmium erythraeum), large siliceous phytoplankton (diatoms), and small non-siliceous phytoplankton (microflagellates) explored the sequence of events required to support the observed red tide from August to December 2001. The ecological model contained 24 state variables within five submodels: circulation, atmospheric (iron deposition), bio-optics, pelagic (phytoplankton, nutrients, bacteria, zooplankton, and fish), and benthic (nutrient regeneration). The 2001 model results reaffirmed that diazotrophs are the basis for initiation of red tides of K. brevis on the WFS. A combination of selective grazing pressure, iron fertilization, low molar nitrogen to phosphorus ratios, and eventual silica limitation of fast-growing diatoms set the stage for dominance of nitrogen fixers. New nitrogen was made available for subsequent blooms of K. brevis through the release of ammonium and urea during nitrogen fixation, as well as during cell lysis, by the Trichodesmium population. Once K. brevis biomass reached ichthyotoxic levels, rapid decay of subsequent fish kills supplied additional organic nutrients for utilization by these opportunistic toxic algae. Both nutrient vectors represented organic non-siliceous sources of nitrogen and phosphorus, further exacerbating silica limitation of the diatom population. The model reproduced this spring transition from a simple estuarine-driven, diatom-based food chain to a complex summer -fall system of Trichodesmium and toxic dinoflagellates. While the model was able to replicate the initiation and maintenance of the 2001 red tide, bloom termination was not captured by this 1-D form on the WFS., The original document contains color images. Published in Continental Shelf Research v41 p92 110, 26 Apr 2012. Prepared in cooperation with the College of Marine Science, University of South Florida, St. Petersburg. Sponsored in part by NOAA and NASA NNX09AT48G.

Published
2012

48. LAB-EXPERIMENTAL (PRE-CLINICAL) THERAPEUTICS AND PHARMACOLOGY

Author

Yang, F. H., primary, Zhang, B., additional, Zhou, D. J., additional, Bie, L., additional, Tom, M. W., additional, Drummond, D. C., additional, Nicolaides, T., additional, Mueller, S., additional, Banerjee, A., additional, Park, J. W., additional, Prados, M. D., additional, James, D. C., additional, Gupta, N., additional, Hashizume, R., additional, Strohbehn, G. W., additional, Zhou, J., additional, Fu, M., additional, Patel, T. R., additional, Piepmeier, J. M., additional, Saltzman, W. M., additional, Xie, Q., additional, Johnson, J., additional, Bradley, R., additional, Ascierto, M. L., additional, Kang, L., additional, Koeman, J., additional, Marincola, F. M., additional, Briggs, M., additional, Tanner, K., additional, Vande Woude, G. F., additional, Tanaka, S., additional, Klofas, L. K., additional, Wakimoto, H., additional, Borger, D. R., additional, Iafrate, A. J., additional, Batchelor, T. T., additional, Chi, A. S., additional, Madhankumar, A. B., additional, Slagle-Webb, B., additional, Rizk, E., additional, Harbaugh, K., additional, Connor, J. R., additional, Sarkar, G., additional, Curran, G. L., additional, Jenkins, R. B., additional, Kurozumi, K., additional, Ichikawa, T., additional, Onishi, M., additional, Fujii, K., additional, Ishida, J., additional, Shimazu, Y., additional, Date, I., additional, Ebsworth, K., additional, Walters, M. J., additional, Ertl, L. S., additional, Wang, Y., additional, Berahovich, R. D., additional, Zhang, P., additional, Powers, J. P., additional, Liu, S.-C., additional, Al Omran, R., additional, Sullivan, T. J., additional, Jaen, J. C., additional, Brown, M., additional, Schall, T. J., additional, Yusuke, N., additional, Shimizu, S., additional, Shishido-Hara, Y., additional, Shiokawa, Y., additional, Nagane, M., additional, Wang, J., additional, Sai, K., additional, Chen, F.-R., additional, Chen, Z.-P., additional, Shi, Z., additional, Zhang, J., additional, Zhang, K., additional, Han, L., additional, Chen, L., additional, Qian, X., additional, Zhang, A., additional, Wang, G., additional, Jia, Z., additional, Pu, P., additional, Kang, C., additional, Kong, L.-Y., additional, Doucette, T. A., additional, Ferguson, S. D., additional, Hachem, J., additional, Yang, Y., additional, Wei, J., additional, Priebe, W., additional, Fuller, G. N., additional, Qiao, W., additional, Rao, G., additional, Heimberger, A. B., additional, Chen, P.-Y., additional, Ozawa, T., additional, Drummond, D., additional, Santos, R., additional, Torre, J. D., additional, Ng, C., additional, Lepe, E. L., additional, Butowski, N., additional, Prados, M., additional, Bankiewicz, K., additional, James, C. D., additional, Cheng, Z., additional, Gong, Y., additional, Ma, Y., additional, Muller-Knapp, S., additional, Knapp, S., additional, Antonio Chiocca, E., additional, Kaur, B., additional, Yu, J. S., additional, Judkowski, V., additional, Bunying, A., additional, Ji, J., additional, Li, Z., additional, Bender, J., additional, Pinilla, C., additional, Srinivasan, V., additional, Dombovy-Johnson, M., additional, Carson-Walter, E., additional, Walter, K., additional, Xu, Z., additional, Popp, B., additional, Schlesinger, D., additional, Gray, L., additional, Sheehan, J., additional, Keir, S. T., additional, Friedman, H. S., additional, Bigner, D. D., additional, Kut, C., additional, Tyler, B., additional, McVeigh, E., additional, Li, X., additional, Herzka, D., additional, Grossman, S., additional, Lasky, J. L., additional, Panosyan, E., additional, Meisen, W. H., additional, Hardcastle, J., additional, Wojton, J., additional, Wohleb, E., additional, Alvarez-Breckenridge, C., additional, Nowicki, M., additional, Godbout, J., additional, Lee, S. Y., additional, Sheehan, J. M., additional, Yin, S., additional, Kaluz, S., additional, Devi, S. N., additional, de Noronha, R., additional, Nicolaou, K. C., additional, Van Meir, E. G., additional, Lachowicz, J. E., additional, Demeule, M., additional, Che, C., additional, Tripathy, S., additional, Jarvis, S., additional, Currie, J.-C., additional, Regina, A., additional, Nguyen, T., additional, Castaigne, J.-P., additional, Zielinska-Chomej, K., additional, Mohanty, C., additional, Viktorsson, K., additional, Lewensohn, R., additional, Driscoll, J. J., additional, Alsidawi, S., additional, Warnick, R. E., additional, Rixe, O., additional, deCarvalho, A. C., additional, Irtenkauf, S., additional, Hasselbach, L., additional, Xin, H., additional, Mikkelsen, T., additional, Sherman, J. H., additional, Siu, A., additional, Volotskova, O., additional, Keidar, M., additional, Gibo, D. M., additional, Dickinson, P., additional, Robertson, J., additional, Rossmeisl, J., additional, Debinski, W., additional, Nair, S., additional, Schmittling, R., additional, Boczkowski, D., additional, Archer, G., additional, Sampson, J. H., additional, Mitchell, D. A., additional, Miller, I. S., additional, Didier, S., additional, Murray, D. W., additional, Issaivanan, M., additional, Coniglio, S. J., additional, Segall, J. E., additional, Al-Abed, Y., additional, Symons, M., additional, Fotovati, A., additional, Hu, K., additional, Triscott, J., additional, Bacha, J., additional, Brown, D. M., additional, Dunn, S. E., additional, Daniels, D. J., additional, Peterson, T. E., additional, Dietz, A. B., additional, Knutson, G. J., additional, Parney, I. F., additional, Diaz, R. J., additional, Golbourn, B., additional, Picard, D., additional, Smith, C., additional, Huang, A., additional, Rutka, J., additional, Saito, N., additional, Fu, J., additional, Yao, J., additional, Wang, S., additional, Koul, D., additional, Yung, W. K. A., additional, Yuan, Y., additional, Sulman, E. P., additional, Colman, H., additional, Lang, F. F., additional, Slat, E. A., additional, Herzog, E. D., additional, Rubin, J. B., additional, Carminucci, A. S., additional, Amendolara, B., additional, Leung, R., additional, Lei, L., additional, Canoll, P., additional, Bruce, J. N., additional, Wojton, J. A., additional, Chu, Z., additional, Kwon, C.-H., additional, Chow, L. M., additional, Palascak, M., additional, Franco, R., additional, Bourdeau, T., additional, Thornton, S., additional, Qi, X., additional, Kitange, G. J., additional, Mladek, A. C., additional, Su, D., additional, Carlson, B. L., additional, Schroeder, M. A., additional, Pokorny, J. L., additional, Bakken, K. K., additional, Gupta, S. K., additional, Decker, P. A., additional, Wu, W., additional, Sarkaria, J. N., additional, Oddou, M. P., additional, Mollard, A., additional, Call, L. T., additional, Vakayalapati, H., additional, Warner, S. L., additional, Sharma, S., additional, Bearss, D. J., additional, Chen, T. C., additional, Cho, H., additional, Wang, W., additional, Hofman, F. M., additional, Flores, C. T., additional, Snyder, D., additional, Sanchez-Perez, L., additional, Pham, C., additional, Friedman, H., additional, Woolf, E., additional, Abdelwahab, M. G., additional, Turner, G., additional, Preul, M. C., additional, Lynch, A., additional, Rho, J. M., additional, Scheck, A. C., additional, Salphati, L., additional, Heffron, T. P., additional, Alicke, B., additional, Barck, K., additional, Carano, R. A., additional, Cheong, J., additional, Greve, J., additional, Lee, L. B., additional, Nishimura, M., additional, Pang, J., additional, Plise, E. G., additional, Reslan, H. B., additional, Zhang, X., additional, GOuld, S. G., additional, Olivero, A. G., additional, Phillips, H. S., additional, Zadeh, G., additional, Jalali, S., additional, Voce, D., additional, Wei, Z., additional, Shijun, K., additional, Nikolai, K., additional, Josh, W., additional, Clayton, C., additional, Bakhtiar, Y., additional, Alkins, R., additional, Burgess, A., additional, Ganguly, M., additional, Wels, W., additional, Hynynen, K., additional, Li, Y. M., additional, Jun, H., additional, Daniel, V., additional, Walter, H. A., additional, Nakashima, H., additional, Nguyen, T. T., additional, Shalkh, I., additional, Goins, W. F., additional, Chiocca, E. A., additional, Pyko, I. V., additional, Nakada, M., additional, Furuyama, N., additional, Lei, T., additional, Hayashi, Y., additional, Kawakami, K., additional, Minamoto, T., additional, Fedulau, A. S., additional, and Hamada, J.-i., additional

Published
2012
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