- Professor Yuejian Wang
Graphene at extreme conditions
Mentor: Yuejian Wang (Physics - High pressure Raman spectroscopy)
The importance of graphene has been manifested in the 2010 Nobel Prize on physics awarded to two physics Professor who made this kind of material, a flake of carbon with thickness of just one atom, and discovered the exceptional property it possesses. From 1990s we have two hottest research areas in the materials physics, and both are associated with element carbon: one is carbon nanotubes and another one is graphene, a relative new member of carbon family. Carbon nanotubes have been studied in various perspectives by using as many experimental techniques as available so far. However, for graphene, there is a different story in particular with respect to the high-pressure investigation. By far we can only find one paper focusing on the high-pressure study of graphene by using diamond anvil cell . It addressed the effect of the substrates on the compressibility of graphene and elucidated the trend of Raman modes as a function of thickness under high-pressure conditions. However, the study provided very limited information regarding the phase transition as well as the mechanical properties of Graphene because the highest pressure reached during measurement was relatively low (8 GPa) and Raman system used as the characterization tool is not a powerful probe for the detection of those properties. Graphene has been suggested to be a potential material for making the ultrasensitive strain sensor . Therefore the knowledge of the elastic properties under stress is the mandatory prerequisite prior to the function realization. Also we need to know the phase relation under compression, because different phases have the different sensitivity and give the different response in the stress environment. Meanwhile, the measurement of the phase transition and elastic properties will enable us to understand the unique nature of graphene and confirm the conclusions obtained by other experimental method, e.g. atomic force microscopy. Based on this reality, we plan to employ the diamond anvil cell in conjunction with high-energy synchrotron X-ray source at national facilities to measure and monitor the changes of graphene under compression and decompression at room temperature. Another benefit of this study is that we can compare the behavior of graphene under cold compression with that of graphite on which we have plenty of experiences and achievements, and thus give us a sense of how the crystalline status of carbon materials relates with their function and performance.
- John E. Proctor, Eugene Gregoryanz, Konstantin S. Novoselov, Mustafa Lotya, Jonathan N. Coleman, Matthew P. Halsall, High-pressure Raman spectroscopy of graphene, Phys. Rev. B 80, 073408 (2009)
- Ting Yu, Zhenhua Ni, Chaoling Du, Yumeng You, Yingying Wang and Zexiang Shen, Raman Mapping Investigation of Graphene on Transparent Flexible Substrate: The Strain Effect, J. Phys. Chem. C, 2008, 112 (33), pp 12602–12605
- Professor Amy Banes-Berceli
Molecular mechanisms of hypertension
Mentor: Amy Banes-Berceli (Biology - Role of Altered Intracellular Signaling Mechanisms in the Development and Maintenance of Hypertension)
My lab focuses on understanding the molecular mechanisms of the vascular and renal complications of hypertension and diabetes. Alterations in the walls of the blood vessels, large and small, are necessary to protect them from the increased pressure they see in hypertension. These changes which start as beneficial adaptations can go awry and cause other problems like atherosclerosis, reduced lumen diameter, stiffening of arterial walls and loss of compliance, and thickening of filtration membranes. Ultimately, these all lead to problems in organ functions. Students in my lab will use a variety of techniques including Western Blot analyses, protein assays, immunoprecipitations, immunohistochemistry, myographs, in vivo, ex vivo and in vitro study models, blood pressure and heart rate measurements, kidney function tests, urinalysis.
- Professor George Martins
TELESCOPING CARBON NANOTUBE DEVICES: ROTATIONAL DEGREE OF FREEDOM
Mentors: George Martins(Physics - Numerical)
The main line of research of Dr. Martins is numerical methods applied to
strongly correlated electrons (cuprates, ladders, spin chains, Kondo
effect in nanostructures, frustrated magnets, and, more recently,
pnictides). In the first year of the SMaRT program, research involving the
Kondo effect in carbon nanotubes (CNTs)  was attempted, but
proved too difficult for an undergraduate without firm knowledge of
quantum mechanics, condensed matter physics, and some knowledge of many-body physics (for recent work by
the PI in this area, see [37,38]). In the following year, a project in molecular dynamics (MD) simulation of a
nanodevice involving CNTs proved much more effective in getting the students to produce final results that were
presented in a few conferences. In the third year, this project was expanded and a publication has just been
submitted , involving the PI and 4 undergrad students (two females). For the next three years, this approach
will be expanded. CNT Nanoelectromechanical Systems (NEMS) are becoming ubiquitous (for reviews, see [40-42]),
and many experimental realizations of different configurations have served as proofs of principle that they are
feasible and can possibly surpass conventional microelectronics [43-46]. In particular, the experimental realization
of CNT ‘linear bearings’  (also referred to as ‘telescoping double-wall CNTs’, see figure), and its initial
theoretical understanding , has given origin to many ideas for possible nanoelectronic devices [40-42, 49,50],
greatly increasing the need for an understanding of the mechanic and electrostatic behavior of double-wall CNTbased
systems. MD has been a preferred tool for achieving that [51-54]. The project proposed here involves the
simulation of the rotational motion of a telescoping CNT double wall device . The rotational degree of freedom
of telescoping nanotubes will be incorporated to the oscillatory motion studied in the last year of the SMaRT
program . It became apparent at the end of the previous research , that the relative rotation of the two
CNTs (see figure), could have important effects in the device operation, but no detailed analysis was possible, for
lack of time. The 2011 student will start by mastering the use of Nanoengineer-1 and Lammps. The first
(http://nanoengineer-1.com/content/) provides an intuitive GUI interface to create nanostructures, and the
second (http://lammps.sandia.gov/) is a robust command-based MD software to run simulations. At the same
time, the student will read the literature describing the operation of this and similar devices [39,49], understanding
the need to take rotations into account [39,54], and then analyzing its effect in the device being modeled. Ten
weeks should be more than enough to do that. Understanding the possible application of the telescoping concept
to build an AFM device  will also be investigated. The student will learn Fortran90 programming to transfer the
output of one MD software (NE1) into the input of the other (Lammps) and how to manipulate and visualize large
quantities of data (the MD simulations), extracting (through software he/she will write) from it the data relevant to
the phenomenon being analyzed (for example, the relative angle of rotation of the double CNT, as a function of the
position of the center of mass of the internal CNT). The student will acquire skills with and knowledge about MD,
Fortran90 programming, NEMS, CNTs, graphing, data visualization and presentation, and will train the application
of basic physical concepts. The student is expected, by the end of the summer, to be able to model a realistic
CNT/graphene based NEMS, create its molecular structure with NE1, and analyze its properties using Lammps.
Current undergrad students working with the PI are analyzing the efficiency of CNTs for seawater filtration. Dr.
Ken Elder, being a specialist in MD simulations, will be an invaluable addition to this project. He will deliver a series
of short tutorials on the basic ideas of MD and will help the students with details of operation of Lammps.
- Saito R, Dresselhaus G, Dresselhaus MS. Physical properties of carbon nanotubes, Imperial College,
- Busser CA, Martins GB. Numerical results indicate a half-filling SU(4) Kondo state in carbon nanotubes,
Phys. Rev. B, 75:045406 (2007).
- Mizuno M, Kim EH, Martins GB. Transport and strong-correlation phenomena in carbon nanotube
quantum dots in a magnetic field, J. Phys.: Condens. Matter, 21:292203 (2009).
- Colby R, BurkeK, Dumas S, Fekel D, Martins G. Telescoping carbon nanotube devices: A study using
nanoengineer-1. Nanoscape (to be submitted).
- Li C, Thostenson ET, Chou T-W. Sensors and actuators based on carbon nanotubes and their composites:
A review. Composites Science and Technology, 68:1227-1249 (2008).
- Sharma P, Ahuja P. Recent advances in carbon nanotube-based electronics. Materials Research Bulletin
- Robertson J. Growth of nanotubes for electronics. Materials Today, 10:36-43 (2007).
- Baughman RH, Cui C, Zakhidov AA, Iqbal Z, Barisci JN, Spinks GM, Wallace GG, Mazzoldi A, DeRossi D,
Rinzler AG, Jaschinski O, Roth S, and Kertesz M, Carbon Nanotube Actuators, Science 284, 1340 (1999).
- Fennimore AM, Yuzvinsky TD, Han W-Q, Fuhrer MS, Cumings J, Zettl A. Rotational actuators based on
carbon nanotubes. Nature, 424, 408-410 (2003).
- Bourlon B, Glattli DC, Miko C, Forro L, Bachtold A. Carbon nanotube based bearing for rotational motions.
Nano Lett., 4:710-712 (2004).
- Cumings J, Zettl A. Low-friction nanoscale linear bearing realized from multiwall carbon nanotubes.
Science, 289:602-604 (2000).
- Kolmogorov AN, Crespi VH. Smoothest bearings: Interlayer sliding in multiwalled carbon nanotubes. Phys.
Rev. Lett., 85:4727-4730 (2000).
- Zheng Q, Jiang Q. Multiwalled carbon nanotubes as gigahertz oscillators. Phys. Rev. Lett., 88:045503
- Kang JW, Jiang Q. Electrostatically telescoping nanotube nonvolatile memory device. Nanotechnology,
- Legoas SB, Coluci VR, Braga SF, Coura PZ, Dantas SO, Galvao DS. Molecular-dynamics simulations of
carbon nanotubes as gigahertz oscillators. Phys. Rev. Lett., 90:055504 (2003).
- Lebedeva IV, Knizhnik AA, Popov AM, Lozovik YE, Potapkin BV. Dissipation and fluctuations in
nanoelectromechanical systems based on carbon nanotubes. Nanotechnology, 20:105202 (2009).
- Somada H, Hirahara K, Akita S, Nakayama Y. A molecular linear motor consisting of carbon nanotubes.
Nano Letters, 9:62-65 (2009).
- Tu ZC, Ou-Yang ZC. A molecular motor constructed from a double-walled carbon nanotube driven by
temperature variation. J. Phys.: Condens. Matter, 16:1287-1292 (2004).
- Popescu A, Woods LM, Bondarev IV. A carbon nanotube oscillator as a surface profiling device.
Nanotechnology, 19:435702 (2008).
- Professor Bradley Roth
ANALYSIS OF THE MECHANICAL BIDOMAIN MODEL OF CARDIAC TISSUE
Mentor: Bradley Roth (Biological Physics - Numerical)
The goal of this project is to determine the mechanical behavior of the heart using the mechanical bidomain model of cardiac tissue. This model accounts individually for the intracellular and extracellular forces in the tissue, and forces across the cell membrane . In particular, Roth is interested in the effects of anisotropy (the dependence of the mechanical properties on direction) on the behavior. The student will analyze the equations describing the mechanical bidomain model, perform a perturbation expansion in terms of a small parameters related to tissue anisotropy, and derive the zeroth and first order solutions. These solutions will then be calculated numerically. This will allow the student to gain experience in partial differential equations, basic principles in elasticity, numerical methods for computer simulations, and cardiac biomechanics. The student will be expected to summarize the results in a scientific paper that will be submitted for publication to a peer-reviewed journal. In the past, undergraduate students have contributed significantly to research with Roth. For instance, during the summer of 2007 two undergraduate students from the SMaRT REU program (Kaytlin Brinker and Nancy Tseng) worked on projects that led to two excellent publications [1,3]. Brinker’s paper has already started being cited by other researchers. In 2008, SMaRT undergraduate Kevin Schalte published in the journal Medical & Biological Engineering & Computing . Last year, undergraduate Venessa Punal analyzed the mechanical bidomain model, calculated the displacement throughout the tissue (see Figure), and published her results . These accomplishments prove that undergraduate students are able to contribute significantly to this research.
- Tseng N, Roth BJ. The potential induced in anisotropic tissue by the ultrasonically-induced Lorentz force. Med. Biol. Eng. Comput., 46:195-197 (2008).
- Roth BJ, Schalte K. Ultrasonically-induced Lorentz force tomography. Med. Biol. Eng. Comput., 47:573-577 (2009).
- Brinker K, Roth BJ. The effect of electrical anisotropy during magneto-acoustic tomography with magnetic induction. IEEE Trans. Biomed. Eng., 55:1637-1639 (2008).
- Punal VM, Roth BJ. A perturbation solution of the mechanical bidomain model. Biomechanics and Modeling in Mechanobiology, 11:995-1000 (20012).
- Professor Ferman Chavez
SELF-ASSEMBLY OF FERROMAGMETIC - FERROELECTRIC CORE-SHELL NANOPARTICLES
Mentor: Ferman Chavez (Chemistry – Experimental)
This project is on chemical reaction mediated self assembly of magnetic and ferroelectric core shell nanoparticles. The aim is to synthesize new composite materials that respond to a variety of force fields including magnetic, electric and mechanical forces. Such nano-materials are of interest for use in sensors and signal processing devices. The students will prepare nanoparticles by coprecipitation and coat the magnetic and ferroelectric particles with complementary coupling groups and allow them to self-assemble into heterogeneously coupled materials. Measurements on the assembled composites will include x-ray diffraction, scanning and transmission electron microscopy (Fig.1), magnetic and ferroelectric properties, and studies on magneto-electric cross-coupling.
- Professor Gopalan Srinivasan
SELF-ASSEMBLED MULTIFERROIC NANOSTRUCTURES AND STUDIES ON MAGNETOELECTRIC INTERACTIONS
Mentor: Gopalan Srinivasan (Physics, Materials – Experimental)
Ferromagnetic-ferroelectric composites are of interest for the conversion of magnetic field to an electric field and vice versa. The field conversion occurs through mechanical forces, i.e., magnetic field induced strain due to magnetostriction is converted to an electric field due to piezoelectric effect. The planned project is on novel self-assembled ferromagnetic-ferroelectric nanostructures and studies on magnetoelectric (ME) interactions.
The research involves preparation and characterization of coaxial fibers of ferromagnetic and ferroelectric oxides. Students will be involved in all aspects of the research, including synthesis of nanostructures, electric and magnetic field driven assembly, and characterization. They will also participate in software development for data acquisition.
Specific tasks are as follows:
- Synthesis of nickel ferrite and PZT nanoparticles (10-100 nm) by co-precipitation
- Preparation of sol of ferrite and PZT
- Use of the sol in a dual syringe pump and electrospinning using a coaxial needle (Fig.1)
- Characterization of annealed fibers by SPM, SEM, EDAX and XRD
- Assemble the nanofiber building blocks into superstructures of rings, and 2D and 3D periodic arrays by magnetic field-driven techniques and by electrophoretic deposition
- Studies on low-frequency and resonance ME effects over 1 mHz – 110 GHz and negative-index characteristics.