NIST Technicalendar March 31 to April 4, 2008 The NIST Technicalendar is issued each Friday. All items MUST be submitted electronically from this web page by 12:00 NOON each Wednesday unless otherwise stated in the NIST Technicalendar. The address for online weekly editions of the NIST Technicalendar and NIST Administrative Calendar is: http://www.nist.gov/tcal/.

In this Issue: Meetings at NIST Meetings Elsewhere Announcements Talks by NIST Personnel NIST Web Site Announcements NIST Administrative Calendar (current)   NIST Vacancy Announcements (current)

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8:00 AM - Annual Fire Conference
10:30 AM - Nanostructured Origami: Stress-Engineering of Nanopatterned Membranes to Produce 3D Structures

3:00 PM - Fluctuation Effects on Propagating Waves of Self-Assembly in Organosilane Monolayers

No Scheduled Events

10:30 AM - Imaging ultrafast dynamics with electron microscopy: recent advances, challenges and opportunities

10:45 AM - Structural Determination of Nanomaterials with Electrospray Differential Mobility Analysis
1:30 PM - Possible ordered states in graphene bilayers

3/31 -- MONDAY

8:00 AM - BUILDING AND FIRE RESEARCH LABORATORY SEMINAR: Annual Fire Conference
. . , ..
Administration Bldg, Red Auditorium. (NIST Contact: Angela ellis, 301-975-3881, agellis@nist.gov)

10:30 AM - CNST NANOFABRICATION RESEARCH GROUP SEMINAR: Nanostructured Origami: Stress-Engineering of Nanopatterned Membranes to Produce 3D Structures
Folding nanopatterned membranes at arbitrary angles, like origami, allows one to manufacture 3D nanoscale systems. One challenge with this approach is to achieve very small fold radii for tight 3D packing. Stress induced on a thin membrane by helium ion implantation will fold the membrane to a one-micron radius. Incident ion energy and fluence determine the fold angle and direction, and are easily controllable. One application of stress folding is a chemical sensor. Built from a membrane as a 3D micro-switch, the stress that develops in a reactive polymer bends the switch closed. Thus, it consumes little power and responds to target gases with more than a million-fold electrical resistance change. Other 3D membrane architectures may require accurate feature-alignment. This is solved by patterning membranes with magnetic material so they attract in self-alignment when folded together. These advances open the way for future applications to optical devices, for example, artificial dielectrics such as photonic crystals and more general non-periodic metamaterials, which are formed by combining new optical exposure techniques with membrane folding.
William Arora , Graduate Student, will@nano.mit.edu.
217 Bldg, Rm. H107. (NIST Contact: Alex Liddle, 301-975-6050, james.liddle@nist.gov)


4/1 -- TUESDAY

3:00 PM - POLYMERS DIVISION SEMINAR: Fluctuation Effects on Propagating Waves of Self-Assembly in Organosilane Monolayers
Wavefronts associated with reaction–diffusion and self-assembly processes are ubiquitous in the natural world. For example, propagating fronts arise in crystallization and diverse other thermodynamic ordering processes, in polymerization fronts involved in cell movement and division, as well as in the competitive social interactions and population dynamics of animals at much larger scales. Although it is often claimed that self-sustaining or autocatalytic front propagation is well described by mean-field 'reaction– diffusion' or 'phase field' ordering models, it has recently become appreciated from simulations and theoretical arguments that fluctuation effects in lower spatial dimensions can lead to appreciable deviations from the classical mean-field theory(MFT) of this type of front propagation. The present work explores these fluctuation effects in a real physical system. In particular, high-resolution near-edge x-ray absorption fine structure spectroscopy (NEXAFS) is used to study of the spontaneous frontal self-assembly of organosilane (OS) molecules into self-assembled monolayer (SAM) surface-energy gradients on oxidized silicon wafers. We find that these layers organize from the wafer edge as propagating wavefronts having well defined velocities. In accordance with two-dimensional simulations of this type of front propagation that take fluctuation effects into account, the interfacial widths w ( t ) of these SAM self-assembly fronts exhibit a power-law broadening in time rather than the constant width predicted by MFT. Moreover, the observed exponent values accord rather well with previous simulation and theoretical estimates. These observations have significant implications for diverse types of ordering fronts that occur under confinement conditions in biological or materials processing
Jack Douglas , NIST - Polymers Division - Nanostructured Materials, Gaithersburg, MD, jack.douglas@nist.gov.
224 Bldg, Rm. A312. (NIST Contact: Jack Douglas, 301-975-6779, jack.douglas@nist.gov)


4/2 -- WEDNESDAY

No Scheduled Events

4/3 -- THURSDAY

10:30 AM - CNST NANOTECHNOLOGY SEMINAR SERIES: Imaging ultrafast dynamics with electron microscopy: recent advances, challenges and opportunities
Miniaturization of electronic devices with atomic-scale active components is a great technological undertaking and presents a major challenge in metrology. To understand the underlying physics and behavior at the molecular level, which by the very definition is not a static but essentially dynamic process, our group is developing an ultrafast electron microscope (UEM). This methodology combines extreme spatial and temporal resolutions, which allows for the simultaneous characterization of spatiotemporal properties at relevant scales. The versatility of the UEM technology and its applications in electronics, photonics and biotechnology will be illustrated with two distinct examples. The first is the "conventional" pump-probe imaging of ultrafast dynamics during a phase transition in vanadium dioxide, and the second is the direct visualization of a laser controlled reversible transformation in molecular crystals.
Dr. Vladimir Lobastov , California Institute of Technology, lobastov@its.caltech.edu.
215 Bldg., C103 Rm.. (NIST Contact: Nikolai Zhitenev, 301-975-6039, nikolai.zhitenev@nist.gov)


4/4 -- FRIDAY

10:45 AM - NIST CENTER FOR NEUTRON RESEARCH SEMINAR: Structural Determination of Nanomaterials with Electrospray Differential Mobility Analysis
The structure of nanomaterials and biological molecules plays an integral role in their function. In pursuit of NIST's mission to advance measurement science, we have refined electrospray differential mobility analysis (ES-DMA) with the goal of generating multimodal size distributions to inform studies on the structure, assembly, and aggregation of these materials. In ES-DMA, particles suspended in aqueous solution are electrosprayed, separated using a differential mobility analyzer based on their charge-to-size ratio, and then enumerated with a condensation particle counter. The advantages of ES-DMA are that it requires no labeling, provides a direct read-out of particle size distributions, rapidly measures statistically significant populations, and detects changes as small as 0.2 nm. This talk will describe the theory of operation of ES-DMA and provide an overview of our efforts to characterize DNA functionalized gold nanoparticles, the aggregation of nanoclusters and antibodies, and virus particles.
Leonard Pease , NIST CSTL,. ,.
235 Bldg, Rm. E100. (NIST Contact: Susan Krueger, 301-975-6734, susan.krueger@nist.gov)

1:30 PM - CNST ELECTRON PHYSICS GROUP SEMINAR: Possible ordered states in graphene bilayers
Graphene is a two dimensional honeycomb lattice of carbon atoms which has recently attracted considerable attention because of rapid experimental progress, and because of its novel physical properties. In this talk, I will discuss recent theoretical work in which I have proposed new types of ordered electronic states in graphene bilayers, including excitonic superfluids which could have remarkably high transition temperatures. My talk will conclude with some speculations on the possibility of radically new types of electronic devices in these systems whose operation is based on collective electronic behavior.
Hongki Min , University of Texas at Austin, hongki@physics.utexas.edu.
217 Bldg, Rm. H107. (NIST Contact: Mark Stiles, 301-975-3745, mark.stiles@nist.gov)


ADVANCE NOTICE

4/7/08 11:00 AM - POLYMERS DIVISION SEMINAR: Contraction-Expansion Flows of Concentrated Suspensions and Novel Biopolymer Gel Tracer Particles
Intensive research efforts into flows of concentrated suspensions have yielded experimental data, continuum models and numerical simulations that are useful for suspension flows in simple geometries such as circular pipes. However, for many complex flow geometries, modeling calculations and experimental data are rare, even though such geometries are frequently encountered in materials processing operations. This talk will focus on an experimental investigation of concentrated suspension behavior in contraction-expansion flows, using nuclear magnetic resonance imaging (NMRI) and microfluidics measurement techniques. Results indicate that the effective viscosity ratios between various regions at the flow inlet are strongly correlated with important observed features of the system, such as recirculation region size and pressure drop. The development of novel biopolymer gel tracer particles also provides expanded capabilities in the study of suspensions, emulsions, and granular flows.
Nina Shapley , Professor at Columbia University, Department of Chemical Engineering, New York, NY, ncs2101@columbia.edu.
224 Bldg, Rm. A312. (NIST Contact: Kalman Migler, 301-975-4876, kalman.migler@nist.gov)

4/9/08 10:30 AM - CERAMICS DIVISION SEMINAR: Molecular-Based Design of Materials: The Quest for Super Infrastructure Materials
Two recent events make it possible for revolutionary improvements in construction materials to occur. The first is the growing development and use of Molecular-Based Predictive Rheology. Using ab initio (Quantum Mechanics) and molecular dynamics simulations, the rheologic properties of a material can now be predicted with increasing accuracy based on the atomic and molecular structure of the material. Molecular-Based Predictive Rheology not only provides the ability to predict how a material responds to loads before the material in synthesized, it also provides in-depth insight into the interactions between atoms and molecules that determine this response. Thus it allows for the intelligent design of materials at the molecular level to achieve desired material behavior. The second event is the discovery of carbon nanotubes. Carbon nanotubes are very small, with diameters that range up to a few tens of nanometers, or on the order of a 1/thousandth the diameter of a human hair. They have been grown to lengths of several inches, and researchers are attempting to grow them still longer. They have unprecedented properties as the basis for construction materials. These include tensile strengths to 15.5 million psi, which is about 150-times that of high-strength steel, stiffness (Young's modulus) of 150 million psi, which is about 5-times that of steel, and densities that range from 1/6 to 1/3 that of steel. They have strength-to-weight ratios that range from about 450 to 900 times that of steel. Three recently-inaugurated U.S. Army Engineer Research and Development Center research programs seek to take advantage of these two events to change the paradigm of construction material development. The first two of these research programs are basic research programs that are further developing the science and tools of Molecular-Based Predictive Rheology, and then are using these tools to understand some of the phenomena relating the molecular make-up of carbon nanotube-based constructs to their rheologic properties. The third program is an applied research program that will use this understanding, and the predictive methods to design carbon nanotube-based filaments, membranes, and coatings to Technology Readiness Level 4 (TRL-4) that have tensile strengths of 1-million psi, with associated densities of about 1/5 that of steel. If successful, the developed materials will have about twice the strength-to-weight ratio of Kevlar, and about 5-times the tensile strength of very-high strength (4340 alloy) steel. These goals are to be met by 2010. At that time these laboratory materials may turn out to be prohibitively expensive, but then research will begin on how to make these materials cheaper. This talk will discuss some of the research associated with these programs.
Dr. Robert Welch , U.S. Army Corps of Engineers, Vicksburg, MS.
Materials Building, Rm. B351. (NIST Contact: Robert Cook, 301-975-3207, robert.cook@nist.gov)

4/11/08 10:30 AM - NIST COLLOQUIUM SERIES: Observing Climate with Satellites: Are We on Thin Ice?
The Earth's climate is determined by irradiance from the Sun and by properties of the atmosphere, oceans, and land that determine the reflection, absorption, and emission of energy within our atmosphere and at the Earth's surface. Since the 1970s, Earth-viewing satellites have complemented non-satellite geophysical information that together has led to an unprecedented understanding of the Earth's coupled ocean-land-atmosphere system. The speaker will discuss the elaboration of the Earth's climate system that has resulted from earth-viewing satellites and ground-based geophysical monitoring stations, review claims by climate change skeptics who argue against global warming, and show the unprecedented convergence of evidence for global warming in the past few years. He will also discuss recent concerns about warming-induced instabilities to the ice sheets of Greenland and Antarctica. Compton Tucker is a senior earth scientist at NASA's Goddard Space Flight Center. His research has involved studying global net primary production, measuring tropical deforestation, climatically-linked diseases, and glacier variations over time. He is the author of 140 journal articles on the use of satellite data to study the earth.
Compton Tucker , Goddard Fellow, NASA Goddard Space Flight Center.
Administration Building, Green Auditorium. (NIST Contact: Kum Ham, 301-975-4203, kham@nist.gov)
Special Assistance Available

4/11/08 10:30 AM - ATOMIC PHYSICS DIVISION SEMINAR: Electron Spin Decoherence in Semiconductor Quantum Dots
Spins in semiconductor nanostructures are promising qubit candidates for a solid state quantum computer, and have seen truly impressive experimental progresses in the past few years. An important issue in spin-based quantum information processing is how a spin qubit couples to its spin environment. In this talk I will discuss some recent theoretical studies where we analyze the hyperfine coupling between electron and nuclear spins and the resulting coupled dynamics of electron and nuclear spins in a quantum dot. Specifically, I will discuss two decoherence mechanisms arising from the electron spin - nuclear spin interaction.
Xuedong Hu , State University of New York, Buffalo, NY.
Metrology Building, Room B365. (NIST Contact: Neil Zimmerman, 301-975-5887, neil.zimmerman@nist.gov)

4/17/08 10:30 AM - BIOPHYSICS SEMINAR: Laser Assisted Single-Molecule Refolding
In vivo, many RNA molecules can adopt multiple conformations depending on their biological context. For example, an RNA molecule that is initially in a stable hairpin conformation will at a later stage of its biological cycle interact with a second RNA molecule, which in turn will trigger a dimerization reaction of the two molecules. This is the case of the HIV Dimerization Initiation Sequence (DIS) and the DsrA RNA in bacteria. It is quite common that the initial interaction between the two RNAs takes place via complementary unpaired regions, forming a so-called kissing complex. However, the exact kinetic mechanism by which the two RNA molecules reach the dimerized state is still not well understood. To investigate the refolding energy surface of RNA molecules, we have developed new technology based on the combination of single molecule spectroscopy with laser induced temperature jump kinetics, called Laser Assisted Single-molecule Refolding (LASR). LASR enables us to induce folding reactions of otherwise kinetically trapped RNAs at the single molecule level, and to characterize their folding landscape. Single molecule time trajectories show that we can drive the dimerization reaction between two trapped kissing RNA hairpins with LASR and use this data to calculate folding enthalpies and entropies. Our LASR experiments indicate that the RNA kissing complex is a stable intermediate state that facilitates the dimerization reaction. LASR provides an exciting new approach to study molecular memory effects and kinetically trapped RNAs in general. LASR is readily applicable to study DNA and protein folding as well.
David Rueda , Department of Chemistry, Wayne State University, Detroit, MI.
Bldg 217, Room H107. (NIST Contact: Lori Goldner, 301-975-3792, lori.goldner@nist.gov)

4/18/08 1:30 PM - CNST NANOFABRICATION RESEARCH GROUP SEMINAR: Cavity QED with Charged Quantum Dots
We report on nanodevices that for the first time allow for charge tuning of single InAs quantum dots located near the field maximum of high quality micropillar cavities. Through the innovation of a novel trench style cavity design, we are able to embed doped layers for electrical gating within a microcavity and obtain Q values greater than 50,000. Using these devices, we demonstrate record high single photon count rates with a capture efficiency of 38{\%} and a Purcell effect up to 8. We also show high frequency polarization modulation of single photons enabled by Stark shift tuning a charged quantum dot between two polarization modes of a slightly elliptical micropillar with frequencies up to 100 KHz. Furthermore, we demonstrate a charge tunable quantum dot coupled to a micropillar cavity mode, which is an important step in quantum communication protocols involving trapped single electrons or holes. This type of device enables a quick, non-destructive measurement of the spin state of the trapped charge.
Matthew Rakher , Graduate Student Researcher - UCSB Dept. of Physics, rakher@physics.ucsb.edu.
217 Bldg, H107 Rm.. (NIST Contact: Kartik Srinivasan, 301-975-5938, kartik.srinivasan@nist.gov)

5/1/08 10:30 AM - CNST NANOTECHNOLOGY SEMINAR SERIES: The bright future of nanophotonics: recent advances and challenges
Nanophotonics in which light is manipulated at subwavelength scales is emerging as one the most exciting and potentially useful areas of physical optics. I will highlight recent research in my group aimed at a new class of light-sources in which the near field and the far-field properties are fundamentally altered by means of plasmonic nanostructures and metamaterials monolithically integrated on the laser facets. As a platform to demonstrate these new beam shaping concepts, such as reduction of beam divergence, nanospot light concentration, super-focusing and polarization control, we have used mid-infrared and near-IR lasers but these techniques are broadly applicable to all solid-state lasers. I will also discuss a novel technique called nanoskiving that combines photolithography, thin-film metal deposition, and thin-film sectioning, and demonstrate its capabilities in the realization of metallic nanowires with engineered plasmon resonances and frequency selective surfaces.
Federico Capasso , Professor-Harvard University, Cambridge, MA, mullaney@seas.harvard.edu.
215 Bldg, C103- C106 Rm.. (NIST Contact: Nikolai Zhitenev, 301-975-6039, nikolai.zhitenev@nist.gov)

5/16/08 1:30 PM - CENTER FOR NANOSCALE SCIENCE AND TECHNOLOGY SEMINAR: Spin Wave Beams, Precessing Vortices, and Localized Standing Waves in Single Layer Nanocontacts
The recently discovered spin transfer effect enables the application of localized torques in magnetic thin film nanostructures. In the point contact geometry, this effect can result in large amplitude spin wave generation. The well studied Slonczewski model of spin torque in trilayer nanostructures is the Landau-Lifshitz equation modified with a local spin torque term. In this talk, a non-local model of point contacts in single layer thin magnetic films is presented and studied numerically in two spatial dimensions. Here, the spin torque term in the Landau-Lifshitz equation is non-local and is due to spin diffusion effects. A variety of quasi-periodic mode solutions to this equation are found including localized standing waves, vortex spiral waves, and a weakly diffracting collimated beam of spin waves, the direction of which can be steered by changing the direction of an applied magnetic field. The spin wave beam appears to be the nonlinear hybridization of the vortex spiral waves and the localized standing wave. Mode selection is explained using linear spin wave theory.
Dr. Mark Hoefer , Magnetics Group, National Institute of Standards and Technology.
Building 217, Room H107. (NIST Contact: Mark Stiles, 301-975-3745, mark.stiles@nist.gov)

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MEETINGS ELSEWHERE


3/31 -- MONDAY

11:00 AM - CARNEGIE INSTITUTION OF WASHINGTON/GEOPHYSICAL LAB. SEMINAR: CHEMISTRY AND PHYSICS UNDER EXTREME CONDITIONS: CHARACTERIZATION OF KNOWN AND NOVEL SYSTEMS, ELASTICITY OF METALS AND MINERIALS, SHOCK-LOADING COMBINED WITH COMPRESSION
J. Crowhurst , Lawrence Livermore National Lab..
Bldg, Rm..
Greenewalt Bldg., GL-DTM Grounds, Carnegie Institution of Washington, DC. (NIST Contact: A. Goncharov, 202-478-8900, seminar@lists.ciw.edu)



4/1 -- TUESDAY

No Scheduled Events

4/2 -- WEDNESDAY

No Scheduled Events

4/3 -- THURSDAY

No Scheduled Events

4/4 -- FRIDAY

No Scheduled Events

ADVANCE NOTICE

No Scheduled Events

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TALKS BY NIST PERSONNEL

WONG-NG, W. : THERMOELECTRIC RESEARCH AT THE CERAMICS DIVISION OF NATIONAL INSTITUTE OF STANDARDS & TECHNOLOGY.
Columbia University, New York City, New York, USA, 3/28.

SIMMON, E. : UNDERSTANDING THE IPC-175X DATA MODEL.
IPC Printed Circuit Expo / APEX, Las Vegas, NV USA, 4/1.

MESSINA, J. : UNDERSTANDING EU'S REACH AND EUP.
IPC Printed Circuit Expo / APEX, Las Vegas, NV USA, 4/1.

CLARK, C. : CONDENSED MATTER PHYSICS AT NANOGRAMS PER CUBIC CENTIMETER.
Physics Colloquium, University of Kentucky, Lexington, KY, 4/4.

ZEIGER, D. : SAMPLE PREPARATION AFFECTS BACTERIAL ADHESION TO DENTAL POLYMERS.
American Association for Dental Research Meeting, Dallas, TX, 4/5.

LIN, N. : CYTOCOMPATIBILITY OF DENTAL COMPOSITES: EFFECTS OF CONVERSION, FILLER AND ROUGHNESS.
2008 Meeting of the American Association for Dental Research (AADR), Dallas, TX, 4/5.

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ANNOUNCEMENTS

PROTEIN FOLDING, DYNAMICS, AND BINDING FROM SIMULATIONS OF COARSE-GRAINED PROTEIN MODELS
To study the folding, large-scale conformational dynamics, and binding of proteins we develop coarse-grained simulation models that allow us to reach the microsecond time scale and beyond. By extending the concept of structure-based potentials to molecules with multiple conformational states, we are able construct coarse-grained energy surfaces that capture the experimentally determined conformers as distinct local minima. This procedure allows us to explore large-scale conformation changes, including transitions that involve partial, local unfolding of proteins. Additional coarse graining, combined with optimized transferable energy functions and accelerated simulation procedures, allows us to study the slow motions in multi-protein complexes involved in membrane-protein trafficking. Talk presented by Gerhard Hummer, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, at the Center for Advanced Research in Biotechnology, Room 2129 (CARB II), Apr 1, 2:30 pm
NIST Contact: David Plusquellic, 301-975-3896, dplus@nist.gov

NIST SCANNING PROBE MICROSCOPY ISO STANDARDS ADVISORY GROUP FORMING
ISO/TC201/SC9 was launched in 2004 to develop documentary standards for scanning probe microscopy. Initially chartered with five study groups, NIST was requested by ANSI to supply a US delegate to SC9 to chair a study group on scan-parameter and environmental artifacts in AFM imaging. In order to optimize the activities of this study group, the SG3 Chair is trying to develop a forum for greater input from the many other NIST staff involved in scanned probe microscopy and AFM in particular. An informal meeting is tentatively scheduled for April 24 at 1:30 PM in 219/A045. Interested persons are also encouraged to contact the chair individually for more information.
NIST Contact: Ronald Dixson, 301-975-4399, ronald.dixson@nist.gov

VISITOR REGISTRATION FOR NIST EVENTS
Because of heightened security at the NIST Gaithersburg site, members of the public who wish to attend meetings, seminars, lectures, etc. must first register in advance. For more information please call or e-mail the "NIST Contact" for the particular event you would like to attend.
NIST Contact: . ., ., .

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NIST WEB SITE ANNOUNCEMENTS

No Web Site announcements this week.

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For more information, contact Ms. Sharon Hallman, Editor, Stop 2500, National Institute of Standards and Technology, Gaithersburg MD 20899-2500; Telephone: 301-975-TCAL (3570); Fax: 301-926-4431; or Email: tcal@nist.gov.

All lectures and meetings are open unless otherwise stated.

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