NIST Technicalendar August 25 to August 29, 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)

Also available: Previous Issues of the Technicalendar Quick Technicalendar (current) Last week's Quick Technicalendar Last week's Technicalendar Detailed Search NIST Journal of Research (Current TOC) Change User Options

10:30 AM - Mechanical Manipulation and Characterization of Biological Cells – A MEMS and Microrobotics Approach
10:45 AM - Correlation of Microstructure and Magnetotransport in Organic Semiconductor Spin Valve Structures

No Scheduled Events

No Scheduled Events

No Scheduled Events

1:30 PM - Cold Rydberg Atoms

8/25 -- MONDAY

10:30 AM - INTELLIGENT SYSTEMS DIVISION SEMINAR: Mechanical Manipulation and Characterization of Biological Cells – A MEMS and Microrobotics Approach
Living cells are a complex, dynamic entity, continuously adapting and responding to biochemical and mechanical cues. Cellular metabolism and fate can be regulated through the introduction/extraction of biomolecules or through mechanobiological stimuli (e.g., mechanical stimuli, extracellular matrix, and soluble biochemical signals). In this context, we develop enabling MEMS (microelectromechanical systems) tools and microrobotic systems to investigate the effect of controlled mechanical forces and the introduction of foreign biomolecules on cellular processes (e.g., proliferation and protein expression) in a high-throughput manner. This presentation will also introduce our activities in MEMS and microrobotics based mechanical characterization of individual cells at the scale of nano-picoNewton forces and nanometer displacements. Example cell lines in our current research include human umbilical cord perivascular cells, zebrafish embryos, and mouse oocytes/zygotes for applications in regenerative medicine, tissue engineering, reproduction, and genetics.
Yu Sun , Assistant Professor, Dept. of Mechanical and Industrial Engineering, University of Toronto.
Metrology/220 Bldg, Rm. B125. (NIST Contact: Jason Gorman, 301-975-3446, gorman@nist.gov)

10:45 AM - NIST CENTER FOR NEUTRON RESEARCH SEMINAR: Correlation of Microstructure and Magnetotransport in Organic Semiconductor Spin Valve Structures
There is currently a rapidly increasing interest in spin-dependent electronic transport in organic semiconductors (OSC). At its heart, this is based on the expectation that weak spin-orbit coupling in these light-element-based materials will lead to long spin relaxation times and long spin coherence lengths that may ultimately enable their use in magnetoelectronic devices. However, while there are several reports of observation of magnetotransport effects in multilayer OSC spin valve structures, the origins are still under debate, and both spin polarized tunneling and spin-coherent diffusive transport mechanisms have been invoked to explain the observed results. We have studied magnetotransport in several Co/OSC/Fe systems, using Alq3, CuPc, PTCDA and CF3-NTCDI as the spin transport layers. Magnetoresistance (MR) was observed up to room temperature in Alq3 and CuPc based devices. Focusing on the Alq3 system, we studied the devices. microstructure by X-ray reflectometry, Auger electron spectroscopy, and polarized neutron reflectometry. Our study shows evidence for spin-coherent diffusive transport and reveals the correlation between microstructure and magnetotransport in these organic devices. In particular, larger MR effects are associated with smaller average roughness at both the Alq3/Co and Fe/Alq3 interfaces and also with a shaper magnetic boundary at the Alq3/Fe interface, indicating the importance of detailed control and understanding of interfaces in these systems.
Yaohua Liu , Johns Hopkins University.
235 Bldg, Rm. E100. (NIST Contact: Paul Butler, 301-975-2028, paul.butler@nist.gov)


8/26 -- TUESDAY

No Scheduled Events

8/27 -- WEDNESDAY

No Scheduled Events

8/28 -- THURSDAY

No Scheduled Events

8/29 -- FRIDAY

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)


ADVANCE NOTICE

9/2/08 10:30 AM - CNST NANOFABRICATION RESEARCH GROUP SEMINAR: Semiconductor Quantum Dots, Synthesis and Applications
Colloidal semiconductor nanoparticles with nearly perfect crystalline structure have unique optoelectronic properties, such as high quantum efficiency, tunable emission wavelength determined by particle size or elemental ratio of materials to make them, narrow emission and broad absorption profiles, and flexible surface configurations. These properties promise many attractive applications, such as high quality biological probes, high efficient emissive layer in LEDs, and next generation active layer in Photovoltaics. This presentation will discuss the synthesizing of a specific semiconductor quantum dots, alloyed quantum dots through wet chemistry approach, and more importantly, their applications in life science and optoelectronic devices.
Lianhua Qu, PhD , Chief Scientific Officer, Crystalplex Corporation,. ,.
Bldg. 217, Rm. H107. (NIST Contact: Nikolai Zhitenev, 301-975-6039, nikolai.zhitenev@nist.gov)

9/5/08 10:30 AM - NIST COLLOQUIUM SERIES: The Physics of Music and the Music of Quantum Physics
Rolling ripples of water on the surface of a pond, the brilliant colors of a deep rainbow, and Beethoven's symphonies all come to us in the form of waves. While we all appreciate the beauty of these experiences in life without caring about the underlying physics, they become even more beautiful when we dive into their simple physical and mathematical description. This lecture will explore the generation of sound, what makes sound into music, and how we perceive complex sound waves. An attempt will be made to connect music to a different sort of wave physics that appears at the atomic scale: quantum mechanics. While it is difficult to experience quantum waves in the same way as music, there are many interesting analogies between the two, involving measurement, perception, and superposition.
Christopher Monroe , Joint Quantum Institute, University of Maryland Physics Department and NIST.
Administration Building, Green Auditorium. (NIST Contact: Kum Ham, 301-975-4203, kham@nist.gov)
Special Assistance Available

9/11/08 10:30 AM - CNST NANOFABRICATION RESEARCH GROUP SEMINAR: Nanoparticles with key-lock interactions: from self-assembly to drug delivery
By decorating colloidal particles and other nano-objects with various biomolecules, one can introduce highly selective key-lock interactions between them. This leads to a new class of systems and problems in soft condensed matter physics. In my talk, I will review a number of theoretical possibilities and recent experimental achievements in this new field. First, I will discuss DNA-mediated self-assembly of nanostructures and nanoclusters. The specificity and tunability of the interactions result in a remarkable morphological diversity of in such systems. In some of the proposed schemes, DNA can be used to essentially "program" the self-assembly of a desired structure. The colloids with type-dependent interactions can also be used for experimental realization of one of the simplest self-replicating system. Its study may shed some light onto such important problems as prebiotic evolution and origin of life. Finally, I will discuss how cooperative key-lock binding can be also utilized to dramatically enhance cell specificity of drug delivery, e.g. in cancer treatment.
Alexei Tkachenko , Physics Department, University of Michigan,.
Bldg. 217, Rm. H107. (NIST Contact: James Liddle, 301-975-6050, james.liddle@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)

---

MEETINGS ELSEWHERE


8/25 -- MONDAY

No Scheduled Events

8/26 -- TUESDAY

No Scheduled Events

8/27 -- WEDNESDAY

No Scheduled Events

8/28 -- THURSDAY

No Scheduled Events

8/29 -- FRIDAY

No Scheduled Events

ADVANCE NOTICE

No Scheduled Events

---

TALKS BY NIST PERSONNEL

OBRZUT, J. : CONDUCTOR INSULATOR TRANSITION IN CARBON-NANOTUBE COMPOSITES.
International Conference on Dielectric Spectroscopy and its Applications, Lyon, France, 8/26.

SHIRLEY, E. : DIFFRACTION ANALYSIS IN OPTICAL DESIGN.
2008 Calcon Technical Calibration Conference, Eccles Conference Center, Utah State University, Logan, Utah, 8/26.

HOUGEN, J. : A NEW TORSION-ROTATION FITTING PROGRAM FOR MOLECULES WITH A SIX-FOLD BARRIER APPLICATION TO FIT OF THE TOLUENE MICROWAVE SPECTRUM.
Prague-Dejvice, Institute of Chemical Technology Czech Technical University, Prague, Czech Republic, 9/3.

---

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

HOW CAN YOUR LAB LIAISON HELP YOU?
Watch this new video podcast and learn what NIST Labs are saying about ISD's Lab Liaisons. (4+ minutes) http://nvl-i.nist.gov/docs/videos/ISD_liaisons/
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: . ., ., .

---

NIST WEB SITE ANNOUNCEMENTS

No Web Site announcements this week.

---

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.

---

NVL Webmaster