NIST Technicalendar August 11 to August 15, 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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No Scheduled Events

10:30 AM - Layer-By-Layer Assembly of Multifunctional Thin Films

10:30 AM - Tailoring the Behavior of Conductive Polymer Nanocomposites Using Non-Covalent Interactions
1:30 PM - Using the Electron Microscope to Correlate Mechanical Properties and Microstructure in Micron- and Nano-scale Systems

10:00 AM - Micro-and Nanomechanical Behavior of Materials
11:00 AM - Semiconductor Nanowire Metrology
3:30 PM - Some Thoughts on Modern Computer Arithmetic

2:00 PM - Acid-degradable Polymeric Nanoparticles for Intracellular Delivery of Nucleic Acids

8/11 -- MONDAY

No Scheduled Events

8/12 -- TUESDAY

10:30 AM - FIRE RESEARCH DIVISION SEMINAR: Layer-By-Layer Assembly of Multifunctional Thin Films
A variety of thin, functional coatings can be produced using layer-by-layer (LbL) assembly. Thin films, typically 1µm thick, are created by alternately exposing a substrate to positively- and negatively-charged molecules or particles in water. This deposition process is repeated until the desired number of "bilayers" (or cationic-anionic pairs) is achieved. Several functionalities (electrically conductive films made with carbon black (or PEDOT) and oxygen barrier films made with clay are described here. Coatings made from poly(acrylic acid) and polyethylenimine stabilized carbon black are able to achieve a sheet resistance of 500 ohm/square with a thickness of 5.4 micrometers. Even greater conductivity and transparency is achieved when poly(ethylene dioxythiophene), doped with poly(styrene sulfonate), is used in place of carbon black. These PEDOT-based assemblies can be protected from UV degradation by layering in UV absorbers such as TiO2 nanoparticles. Coatings of sodium montmorrilonite clay and cationic polyacrylamide, that are less than 600 nm thick, have been produced with an oxygen transmission rate below 0.005 cm3/m2?day. These thin, transparent composites are a good candidate for foil replacement in food packaging and flexible electronics packaging. They may also be able to protect polymeric materials (e.g., elastomeric o-rings) from swelling and other types of degradation. Some initial results and future work using this clay-polymer nano brick wall structure as a flame retardant coating for foam and fabric will also be mentioned.
Prof. Jaime Grunlan , Dept. of Mechanical Engineering, Texas A&M University.
Bldg 224, Rm B245. (NIST Contact: Rodney Bryant, 301-975-6487, rbryant@nist.gov)


8/13 -- WEDNESDAY

10:30 AM - POLYMERS DIVISION SEMINAR: Tailoring the Behavior of Conductive Polymer Nanocomposites Using Non-Covalent Interactions
Jaime Grunlan , Professor of Mechanical Engineering, Texas A&M.
Polymer Building, Room A312. (NIST Contact: Adam Nolte, 301-975-2895, adam.nolte@nist.gov)

1:30 PM - CNST NANOFABRICATION RESEARCH GROUP SEMINAR: Using the Electron Microscope to Correlate Mechanical Properties and Microstructure in Micron- and Nano-scale Systems
Electron microscopy is an important tool for today's materials scientist. One of the reasons for this increased importance is the growing interest in micron- and nano-scale structures. For example, silicon, which is the most used material in today's microelectromechanical systems (MEMS), is an excellent construction material at the micron-scale, because of highly developed processing methods and its high strength. However, it is an inherently brittle material with a low resistance to nano-scale cracks, which causes reliability to be the limiting factor as far as commercial and defense applications are concerned. Because large surface to volume ratios of components in these small structures can cause the governing failure mechanisms as well as the mechanical properties to be different from macro-scale structures, research into mechanical behavior of materials at small length scales has become of great importance. In this talk I will focus on measuring mechanical behavior at these small length scales by presenting a model example from my own research on fatigue of polycrystalline silicon, and specifically focus on the important role that (in-situ) transmission electron microscopy (TEM) plays in the search for underlying physical mechanisms of this failure mode. Whereas bulk silicon is not susceptible to fatigue, micron-scale silicon is. Micron-scale polysilicon structures stress-lifetime behavior was seen in ambient air, shorter lifetimes were found in higher relative humidity environments, and no fatigue failure was found at all in high vacuum. Analytical TEM of the surface oxides in the samples show a four-fold thickening of the surface oxide at stress concentrations after fatigue failure, but no thickening after overload fracture in air or after fatigue cycling in vacuo. These results are explained by a reaction-layer fatigue mechanism; specifically, moisture-assisted sub-critical cracking within a cyclic stress-assisted thickened oxide layer occurs until the crack reaches a critical size to cause catastrophic failure of the entire device. In-situ TEM experiments are in preparation to validate this mechanism by direct observations and can also be extended to study mechanical behavior of nano-scale structures. The latter will be illustrated in the framework of a broader outlook on the application of in-situ TEM in nano-scale science.
Daniel Alsem , Lawrence Berkeley National Laboratory.
Bldg. 217, Rm. H107. (NIST Contact: James Liddle, 301-975-6050, james.liddle@nist.gov)


8/14 -- THURSDAY

10:00 AM - CERAMICS DIVISION SEMINAR: Micro-and Nanomechanical Behavior of Materials
Microelectromechanical systems (MEMS) employ metallic and ceramic thin films in high-performance and safety-critical structural applications with limited understanding of when, why, and how failures will occur. While such a situation is unthinkable for conventional structural applications, the small size of MEMS has allowed many designers to overlook the need to correlate the structure, processing, and mechanical properties of thin films. The primary objective of the Muhlstein Research Group at Penn State is to address this critical problem by exploring the mechanisms of degradation and failure of materials, including the thin films and nanoparticulates used in MEMS. In this presentation we will consider the deformation, fatigue, and fracture behavior of nanostructured silicon nanowires and noble metal films. Particular attention will be given to how the traditional distinctions between ductile and brittle material failure modes become less clear as the length scale of the specimens and/or grain morphologies are reduced below the micron-scale.
Christopher Muhlstein , Penn State University.
Materials Bldg, Rm. B351. (NIST Contact: Robert Cook, 301-975-3207, robert.cook@nist.gov)

11:00 AM - MATERIALS SCIENCE AND ENGINEERING LABORATORY LECTURE SERIES: Semiconductor Nanowire Metrology
Quasi-one-dimensional semiconductor nanostructures (nanowires, nanorods) have attracted considerable interest as potential candidates for a variety of nanoscale electronic and optoelectronic devices such as field emitters, photodetectors, chemical/bio- sensors, and photovoltaic cells. Their prospective advantages over conventional thin-film devices include better structural quality, high surface-to-volume ratio, flexibility of bottom-up device engineering on various substrates and utilization of quantum effects. MSEL's "Semiconductor Nanowires" project is developing metrology for the synthesis, processing, and characterization of semiconductor nanowire structures to enable reliable nanoscale devices for the above applications. We employ catalyst-assisted and catalyst-free chemical vapor deposition (CVD) to fabricate Si, group III nitrides, SiC and ZnO nanowires. For fabricating device test structures, we progressed from "individual nanowire manipulation" to "batch fabrication" processes that are fully compatible and integrateable with Si VLSI processing. Device demonstrations include GaN nanowire back/top-gated field-effect-transistors (FETs) and UV light-emitting diodes (LEDs). The simplicity, reproducibility, and scalability of the approach could enable industrial manufacturing exciting technologies, such as nano-LEDs and nano-lasers for photonic and sensor applications.
Albert Davydov , Project Leader, Metallurgy Division.
Administration Bldg, Green Auditorium. (NIST Contact: Bill Boettinger, 301-975-6160, william.boettinger@nist.gov)

3:30 PM - MATHEMATICAL AND COMPUTATIONAL SCIENCES DIVISION SEMINAR: Some Thoughts on Modern Computer Arithmetic
Wolfgang Walter , Technical University of Dresdon, Germany.
Administration Bldg, Lecture Rm. C. (NIST Contact: Ronald Boisvert, 301-975-3812, boisvert@nist.gov) http://math.nist.gov/mcsd/Seminars/2008/2008-08-14-Walter.html


8/15 -- FRIDAY

2:00 PM - POLYMERS DIVISION,BIOMATERIALS GROUP SEMINAR: Acid-degradable Polymeric Nanoparticles for Intracellular Delivery of Nucleic Acids
Young Kwon , Assistant Professor, Irvine, CA, kwonyj@uci.edu.
Polymer (224) Bldg, Rm. A-312. (NIST Contact: Marcus Cicerone, 301-975-8104, marcus.cicerone@nist.gov) www.nist.gov/polymers


ADVANCE NOTICE

8/18/08 10:30 AM - CNST NANOFABRICATION RESEARCH GROUP SEMINAR: Studying Nanostructures with Light - Massively Parallel Characterization of Individual Carbon Nanotubes
Nanostructures, including single molecules, carbon nanotubes and semiconductor nanowires often exhibit excellent characteristics that are comparable, and in some cases even superior, to the properties of traditional semiconductors. Their electrical and optical properties are determined by the complex interplay between multiple processes occurring in differing length and time scales. Exploring electrical and optical phenomena at this scale therefore requires a tool to investigate these complex, multi-scale processes at the system-wide level. In this talk, I will discuss our approach to investigate the coupling between electronic motion in 1D and 2D nanostructures (nanotubes, nanowires and single layer graphene) and various physical properties, including the electron band map, contact energy barriers, and electron phonon couplings. In particular, we recently developed a novel laser-based microscopy for addressing electrical conductance properties of a large number of individual nanostructures. We applied this technique to successfully characterize a large number of carbon nanotubes grown over a macroscopic area (~millimeters) with a high throughput ( 100/min). Our technique is an important step toward a real-time chemical imaging with which one can monitor electrical conductance change of an array of nanostructures while they are exposed to various chemical reactions.
Jiwoong Park , Department of Chemistry and Chemical Biology, Cornell University.
Bldg. 217, Rm. H107. (NIST Contact: James Liddles, 301-975-6050, james.liddle@nist.gov)

8/19/08 10:30 AM - CNST NANOFABRICATION RESEARCH GROUP SEMINAR: The nonlinear and linear phenomena in silicon nanostructures
Silicon photonics has attracted much attention recently because of its potential for providing a monolithically integrated platform for both linear and nonlinear applications. In this presentation, I'll talk about our recent result on the application of silicon photonics, in both linear and nonlinear regime, including the measurement of silicon's nonlinearities, the formation of optical solitons in a silicon waveguide and EO modulator based on silicon photonic crystal and novel EO polymer.
Jidong Zhang , Dept. of ECE, University of Rochester,.
Bldg. 217, Rm. H107. (NIST Contact: Vladimir Aksyuk, 301-975-2867, vladimir.aksyuk@nist.gov)

8/29/08 1:30 PM - CNST ELECTRON PHYSICS GROUP SEMINAR: Cold Rydberg Atoms
Photo-excitation of atoms in laser-cooled gases allows the creation of gases of cold Rydberg atoms. In these gases at higher densities, rich dynamics stem from electric multipole interactions among the Rydberg atoms. For example, interatomic forces between Rydberg atoms cause state-changing collisions which can significantly increase the kinetic energy of the colliding atoms. I will discuss experiments examining these collisions in which internal energy of the Rydberg atoms is converted into kinetic energy. At lower densities, translationally cold Rydberg atoms are well-suited for spectroscopic studies to measure atomic properties. I will present a recently proposed scheme for driving transitions between Rydberg states via a time-dependent ponderomotive interaction between the Rydberg electron and an applied optical field and discuss experimental efforts to realize this new spectroscopic tool.
Brenton Knuffman , Ph.D. Candidate, University of Michigan, Ann Arbor, MI.
Bldg. 217, Rm. H107. (NIST Contact: Jabez McClelland, 301-975-3721, Jabez.McClelland@nist.gov)

9/15/08 1:30 PM - CNST NANOFABRICATION RESEARCH GROUP SEMINAR: Andreev current induced dissipation in a Superconductor – Normal metal – Superconductor tunnel junction
In the recent years, nano-refrigeration using electron tunneling in hybrid Normal metal - Insulator - Superconductor (N-I-S) junctions has gained increasing attention [1]. Its basic principle is the energy selective tunneling due to the presence of an energy gap in the superconductor density of states. With a sub-gap voltage bias, only the most energetic electrons can tunnel out of the normal metal, leaving behind the electrons with less energy. We have measured with a high resolution the differential conductance of S-I-N-I-S junctions, whose analysis gives us an access to the normal metal electronic temperature as a function of the voltage. A quantitative model is proposed, that includes the electron-phonon coupling and the Kapitza resistance at the interface with the substrate. With this model, we have achieved a thorough description of the charge and heat currents [2]. We have also shown that the normal metal phonon temperature drops significantly below the substrate temperature. At very low temperature (T 200mK) and low bias, the phase coherent Andreev current dominates the quasi-particle current. By analyzing quantitatively the heat balance in the S-I-N-I-S junction, we demonstrate that the Andreev current does carry heat. This thermal contribution heats the normal metal electrons, overriding over a large voltage range the tunneling-based cooling [3].
Sukumar Rajauria , Néel Institute, CNRS and Université Joseph Fourier.
Bldg. 217, Rm. H107. (NIST Contact: James Liddle, 301-975-6050, james.liddle@nist.gov)

9/16/08 10:30 AM - CNST ELECTRON PHYSICS GROUP SEMINAR: Towards quantum information processing using single neutral atoms
To realize quantum information processing with neutral atoms, controlled coherent interaction between them is a fundamental requirement. One approach relies on deterministic coupling of two or more atoms to the mode of a high-finesse optical resonator in the strong coupling regime. We investigate such a coupling between neutral atoms and a resonator under controlled conditions: we load a chosen number of Doppler-cooled caesium atoms from a magneto-optical trap into a standing wave optical dipole trap. The positions of the individual atoms are then determined with sub-micrometer precision, enabling us to prepare, to manipulate and to read out the quantum state of each atom. Using the dipole trap as an optical conveyor belt, the atoms are transported into the mode of a high-finesse optical cavity with a finesse of F=106, leading to a maximum single-atom cooperativity parameter of the order of 50. By observing the transmission of a weak resonant probe laser we can detect the interaction dynamics of a single atom coupled strongly to the cavity field. Cooling by the probe laser extends the observation time to several ten seconds, allowing us to investigate the strength and the stability of coupling, which are crucial parameters for the controlled coherent interaction. Moreover, we analyze the atom-field interaction using a method, essential for the creation and measurement of entanglement.
Mkrtych Khudaverdyan , Ph.D. Student/Institute of Applied Physics, Bonn, Germany.
Bldg. 217, Rm. H107. (NIST Contact: Jabez McClelland, 301-975-3721, Jabez.McClelland@nist.gov)

9/16/08 10:30 AM - ATOMIC PHYSICS DIVISION SEMINAR: Carbon-nanotube field-effect transistors as chemical sensors
Single-walled carbon nanotubes are seamless molecular cylinders that are either metallic or semiconducting nanowires. The conductance of a semiconducting nanotube can be tuned by applying a voltage to a nearby gate electrode, providing a one-dimensional field-effect transistor at the nanometer scale. These transistors are very sensitive detectors: Their electrical properties vary strongly when they are exposed to chemicals. After the first experiments seven years ago, where high sensitivity to NH3 (monitored in farms and industries) and NO2 (an air pollutant from motor vehicle exhaust and other combustion sources) was discovered [1], a strong sensitivity to many other molecules, including oxygen, methane, alcohol vapor and proteins, has also been reported. The cause of the change in electrical properties is still unclear. One possibility is that molecules bind to the surface of the nanotubes and charge transfer occurs between the nanotube and the molecules. A second possibility is a change of the barriers for electrical transport at the interface between the nanotube and the electrical contacts. Understanding the mechanism that causes the response to each chemical is an essential step for the design of efficient sensors. I will discuss an experimental method we recently developed to determine the sensing mechanism. We find that, in the case of NO2, sensing occurs through the contacts [2]. [1] J. Kong, N. R. Franklin, C. Zhou, M. G. Chapline, S. Peng, K. Cho, and H. Dai, Science 287, 622 (2000). [2] J. Zhang, A. Boyd, A. Tselev, M. Paranjape, and P. Barbara, Appl. Phys. Lett. 88, 123112 (2006).
Paola Barbara , Physics Department, Georgetown University.
Physics Building, Room B145. (NIST Contact: Neil Zimmerman, 301-975-5887, neil.zimmerman@nist.gov)

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MEETINGS ELSEWHERE


8/11 -- MONDAY

No Scheduled Events

8/12 -- TUESDAY

No Scheduled Events

8/13 -- WEDNESDAY

No Scheduled Events

8/14 -- THURSDAY

No Scheduled Events

8/15 -- FRIDAY

No Scheduled Events

ADVANCE NOTICE

No Scheduled Events

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TALKS BY NIST PERSONNEL

DELONGCHAMP, D. : CONTROLLABLY ORIENTED SINGLE-CRYSTAL DOMAINS OF A HIGH-PERFORMANCE SEMICONDUCTING POLYMER.
SPIE OTFT VII Conf., San Diego,CA, 8/11.

ANTONUCCI, J. (Co-Authors: A.Giuseppetti , Laboratory Technician, Gaithersburg, MD, tony.giuseppetti@nist.gov J.O'Donnell , Guest Researcher, Gaithersburg, MD, justin.odonnell@nist.gov) ; Schumacher, G., Associate Director (PRC) ; Skrtic, D., Project Leader : EFFECTS OF FILLER; INITIATOR AND CAVITY DESIGN FACTOR ON POLYMERIZATION STRESS DEVELOPED IN DENTAL COMPOSITES.
American Chemical Society (ACS), The 236th ACS National Meeting, Philadelphia, PA, USA, 8/17.

DUNKERS, J. (Co-Authors: L.M.Pakstis H.Lee , Guest Researcher, Gaithersburg, MD, hae-jeong.lee@nist.gov) ;Matos, M. A. ;Cicerone, M.T. : (CONTRIBUTED) CHARACTERIZATION OF LAMININ ON SILANIZED POLYDIMETHYLSILOXANE.
American Chemical Society (ACS), The 236th ACS National Meeting, Philadelphia, Pennsylvania, USA, 8/17.

CICERONE, M. (Co-Author: J.M.Johnson , Guest Researcher, Gaithersburg, MD, jerainne.johnson@nist.gov) : ROLE OF FAST DYNAMICS IN PRESERVATION OF FREEZE-DRIED PROTEINS.
American Chemical Society (ACS), The 236th ACS National Meeting, Philadelphia, Pennsylvania, USA, 8/17.

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ANNOUNCEMENTS

2008 WORLD STANDARDS DAY PAPER COMPETITION
The U.S. standards community will celebrate World Standards Day on Thursday, October 23, 2008, at the Ronald Reagan Building and International Trade Center in Washington, DC. The theme for this year's celebration, "Intelligent and Sustainable Buildings," recognizes the critical role of standards and conformity assessment programs in ensuring safety requirements; facilitating coordination among contractors, builders, engineers, and architects; and incorporating new technologies in design and construction. In conjunction with this year's event, the 2008 World Standards Day sponsors, including NIST will hold the annual paper competition. The 2008 World Standards Day Paper Competition invites papers that use specific examples to show ways that standards and conformity assessment programs are used for intelligent and sustainable buildings. Paper competition winners will be announced and given their awards at the US celebration of World Standards Day. The first place winner will receive a plaque and $2,500. Second and third place winners will receive $1,000 and $500, respectively, along with a certificate. In addition, the winning papers will be published in SES's journal, "Standards Engineering." ELIGIBILITY: The competition is open to U.S.-based individuals in the private sector, government, or academia. Papers may be co-authored. RULES: Entries must be original and not previously published. NIST papers must be processed through WERB or BERB. All paper contest submissions must be received with an official entry form by midnight on August 29, 2008, by the SES Executive Director, 13340 SW 96th Avenue, Miami, Florida, 33176. Complete details and official entry forms are available on the SES website www.ses-standards.org (follow the link for "2008 WSD Paper Competition.") For additional information about the U.S. Celebration of World Standards Day, or to register for the event, please visit www.wsd-us.org.
NIST Contact: Mary Donaldson, 301-975-6197, mary.donaldson@nist.gov

PUBLICATIONS PRINTING DEADLINE AUGUST 14, 2008
August 14 is the last day in FY 2008 to submit materials using FY 2008 funds to the Electronic Information and Publications Group (EIPG) for printing at the Department of Commerce or Government Printing Office. To assure timely processing, bring your Editorial Review Board-approved document or administrative printing job and appropriate paperwork to the EIPG office by close of business on Thursday, August 14, 2008. The office is located on the mezzanine floor of the NIST Research Library in the Admin Building, Room E220. Questions? Ilse Putman, x2780 or Barbara Silcox, x2146.
NIST Contact: Ilse Putman, 301-975-2780, ilse.putman@nist.gov

HOW CAN YOUR LAB LIAISON HELP YOU?
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NIST Contact: Information Desk, 301-975-3052, library@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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