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Faculty Publications

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Full-Text Articles in Engineering

A Cognitive Approach To Vision For A Mobile Robot, Paul Benjamin, Christopher Funk, Damian M. Lyons Apr 2013

A Cognitive Approach To Vision For A Mobile Robot, Paul Benjamin, Christopher Funk, Damian M. Lyons

Faculty Publications

We describe a cognitive vision system for a mobile robot. This system works in a manner similar to the human vision system, using saccadic, vergence and pursuit movements to extract information from visual input. At each fixation, the system builds a 3D model of a small region, combining information about distance, shape, texture and motion. These 3D models are embedded within an overall 3D model of the robot's environment. This approach turns the computer vision problem into a search problem, with the goal of constructing a physically realistic model of the entire environment. At each step, the vision system selects …

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Runoff Of Silvicultural Herbicides Applied Using Best Management Practices, Matthew W. Mcbroom, Jeff Louch, R Scott Beasley, Mingteh Chang, George G. Ice Apr 2013

Runoff Of Silvicultural Herbicides Applied Using Best Management Practices, Matthew W. Mcbroom, Jeff Louch, R Scott Beasley, Mingteh Chang, George G. Ice

Faculty Publications

Nine small (2.2 to 2.9 ha) and four large (70 to 135 ha) watersheds in East Texas, USA, were instrumented to compare herbicide runoff under different silvicultural systems with best management practices (BMPs). Two treatments were evaluated: conventional, with clearcutting, aerial herbicide site preparation, and hand-applied banded herbaceous release; and intensive, in which subsoiling, aerial fertilization, and a second-year aerial herbicide application were added. Herbicides were applied as operational tank mixes. The highest imazapyr concentration found in stream water was 39 mg L‑1 during the first storm after application (23 days after treatment, DAT) and in-stream concentrations …

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Enhanced Nucleate Boiling On Horizontal Hydrophobic-Hydrophilic Carbon Nanotube Coatings, Xianming Dai, Xinyu Huang, Fanghao Yang, Xiaodong Li, Joshua Sightler, Yingchao Yang, Chen Li Apr 2013

Enhanced Nucleate Boiling On Horizontal Hydrophobic-Hydrophilic Carbon Nanotube Coatings, Xianming Dai, Xinyu Huang, Fanghao Yang, Xiaodong Li, Joshua Sightler, Yingchao Yang, Chen Li

Faculty Publications

Ideal hydrophobic-hydrophilic composite cavities are highly desired to enhance nucleate boiling. However, it is challenging and costly to fabricate these types of cavities by conventional micro/nano fabrication techniques. In this study, a type of hydrophobic-hydrophilic composite interfaces were synthesized from functionalized multiwall carbon nanotubes by introducing hydrophilic functional groups on the pristine multiwall carbon nanotubes. This type of carbon nanotube enabled hydrophobic-hydrophilic composite interfaces were systematically characterized. Ideal cavities created by the interfaces were experimentally demonstrated to be the primary reason to substantially enhance nucleate boiling

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Capturing Creative Program Management Best Practices, Brandon Keller, Joseph R. Wirthlin Apr 2013

Capturing Creative Program Management Best Practices, Brandon Keller, Joseph R. Wirthlin

Faculty Publications

This research attempted to capture the creative aspects of government program management in three specific areas: efficiently navigating oversight, capturing the intent of regulations, and developing innovative risk management practices. Respected acquisition leaders with diverse backgrounds and experiences were interviewed with ranks ranging from 0-6 to 0-8 and GS-15 to SES. Several contractor interviews were conducted for specific purposes. The data were iteratively coded and analyzed using ATLAS.ti. The results were categorized into four themes, each with three sub-elements. Differences between respondents with program director experience and those with rapid acquisition experience are discussed. A survey was then distributed to …

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Transforming Synthetic Biology With Cell-Free Systems, Arnaz Ranji, Jeffrey C. Wu, Bradley Charles Bundy, Michael C. Jewett Mar 2013

Transforming Synthetic Biology With Cell-Free Systems, Arnaz Ranji, Jeffrey C. Wu, Bradley Charles Bundy, Michael C. Jewett

Faculty Publications

Cell-free synthetic biology offers an unprecedented level of control and freedom of design for understanding, harnessing, and expanding the capabilities of natural biological systems. Inspired by advances in synthetic biology projects in vivo, recent years have witnessed the emergence of cell-free systems not only as a testing ground for our ability to engineer and analyze biology, but also as technologies capable of efficient and scalable synthesis of complex biological products. Dominant efforts in the field include: programmable nucleic acid circuits; nanomachines; cell-free protein synthesis; cell-free metabolic engineering; and minimal cells. The goals are understanding why nature’s designs work the way …

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A Multiplicative Extended Kalman Filter For Relative Rotorcraft Navigation, Robert C. Leishman, Timothy W. Mclain Mar 2013

A Multiplicative Extended Kalman Filter For Relative Rotorcraft Navigation, Robert C. Leishman, Timothy W. Mclain

Faculty Publications

In this article we detail the fundamentals of a new approach to GPS-denied navigation for aerial vehicles in confined indoor environments. We depart from the common practice of navigating within a globally referenced map, and instead keep the position and yaw states relative to the current node in the map. The approach combines elements of graph SLAM with a multiplicative extended Kalman filter (MEKF). The filter provides quality state estimates at a fast rate and a graph SLAM algorithm maintains a pose graph. We provide specific details for the relative MEKF. We verify the relative estimation approach with hardware flight …

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Effect Of Cd44 Binding Peptide Conjugated To An Engineered Inert Matrix On Maintenance Of Breast Cancer Stem Cells And Tumorsphere Formation, Xiaoming Yang, Samaneh Kamali Sarvestani, Seyedsina Moeinzadeh, Xuezhong He, Esmaiel Jabbari Mar 2013

Effect Of Cd44 Binding Peptide Conjugated To An Engineered Inert Matrix On Maintenance Of Breast Cancer Stem Cells And Tumorsphere Formation, Xiaoming Yang, Samaneh Kamali Sarvestani, Seyedsina Moeinzadeh, Xuezhong He, Esmaiel Jabbari

Faculty Publications

Introduction: As cancer cells are affected by many factors in their microenvironment, a major challenge is to isolate the effect of a specific factor on cancer stem cells (CSCs) while keeping other factors unchanged. We have developed a synthetic inert 3D polyethylene glycol diacrylate (PEGDA) gel culture system as a unique tool to study the effect of microenvironmental factors on CSCs response. We have reported that CSCs formed in the inert PEGDA gel by encapsulation of breast cancer cells maintain their stemness within a certain range of gel stiffness. The objective was to investigate the effect of CD44 binding peptide …

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Atomic Layer Deposition On Porous Materials: Problems With Conventional Approaches To Catalyst And Fuel Cell Electrode Preparation, Tzia Ming Onn, Rainer Küngas, Paolo Fornasiero, Kevin Huang, Raymond J. Gorte Mar 2013

Atomic Layer Deposition On Porous Materials: Problems With Conventional Approaches To Catalyst And Fuel Cell Electrode Preparation, Tzia Ming Onn, Rainer Küngas, Paolo Fornasiero, Kevin Huang, Raymond J. Gorte

Faculty Publications

Atomic layer deposition (ALD) offers exciting possibilities for controlling the structure and composition of surfaces on the atomic scale in heterogeneous catalysts and solid oxide fuel cell (SOFC) electrodes. However, while ALD procedures and equipment are well developed for applications involving flat surfaces, the conditions required for ALD in porous materials with a large surface area need to be very different. The materials (e.g., rare earths and other functional oxides) that are of interest for catalytic applications will also be different. For flat surfaces, rapid cycling, enabled by high carrier-gas flow rates, is necessary in order to rapidly grow thicker …

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First Principles Study On Inp (001)-(2 × 4) Surface Oxidation, Santosh Kc, Weichao Wang, Hong Dong, Ka Xiong, Roberto Longo, Robert Wallace, Kyeongjae Cho Mar 2013

First Principles Study On Inp (001)-(2 × 4) Surface Oxidation, Santosh Kc, Weichao Wang, Hong Dong, Ka Xiong, Roberto Longo, Robert Wallace, Kyeongjae Cho

Faculty Publications

A theoretical study of the oxidation of InP(001)-(2 × 4) surface is performed using density functional theory methods. Our results on surface oxidation show that the oxygen adsorption does not produce any gap states in the bulk InP band gap, due to the saturation of surface In dangling bonds, whereas substitutional oxygen atoms produce gap states. This study also shows that the surface stability increases with the oxygen content, indicating a strong tendency for surface oxidation. Our results help to clarify the origin of surface gap states upon surface oxidation and provide an insight at the atomic level the mechanism …

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Examining The Validity Of Using A Gaussian Schell-Model Source To Model The Scattering Of A Fully Coherent Gaussian Beam From A Rough Impedance Surface, Santasri Basu, Milo W. Hyde Iv, Salvatore J. Cusumano, Michael A. Marciniak, Steven T. Fiorino Mar 2013

Examining The Validity Of Using A Gaussian Schell-Model Source To Model The Scattering Of A Fully Coherent Gaussian Beam From A Rough Impedance Surface, Santasri Basu, Milo W. Hyde Iv, Salvatore J. Cusumano, Michael A. Marciniak, Steven T. Fiorino

Faculty Publications

Military applications that use adaptive optics (AO) often require a point source beacon at the target to measure and correct for wavefront aberrations introduced by atmospheric turbulence. However, turbulence prevents the formation of such a point beacon. The extended beacons that are created instead have finite spatial extents and exhibit varying degrees of spatial coherence. Modeling these extended beacons using a Gaussian Schell-model (GSM) form for the autocorrelation function would be a convenient approach due to the analytical tractability of Gaussian functions. We examine the validity of using such a model by evaluating the field scattered from a rough impedance …

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A Software Tool For The Design Of Critical Robot Missions With Performance Guarantees, Damian M. Lyons, Ronald C. Arkin, Paramesh Nirmal, Shu Jiang, Tsung-Ming Liu Mar 2013

A Software Tool For The Design Of Critical Robot Missions With Performance Guarantees, Damian M. Lyons, Ronald C. Arkin, Paramesh Nirmal, Shu Jiang, Tsung-Ming Liu

Faculty Publications

Deploying a robot as part of a counter-weapons of mass destruction mission demands that the robotic software operates with high assurance. A unique feature of robotic software development is the need to perform predictably in a physical environment that may only be poorly characterized in advance. In this paper, we present an approach to building high assurance software for robot missions carried out in uncertain environments. The software development framework and the verification algorithm, VIPARS, are described in detail. Results are presented for missions including motion and sensing uncertainty, interaction with obstacles, and the use of sensors to guide behavior.

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Note: A Simple Thermal Gradient Annealing Unit For The Treatment Of Thin Films, C. J. Metting, Johnathan K. Bunn, Ellen A. Underwood, Yihao Zhu, G. Koley, T. Crawford, Jason R. Hattrick-Simpers Mar 2013

Note: A Simple Thermal Gradient Annealing Unit For The Treatment Of Thin Films, C. J. Metting, Johnathan K. Bunn, Ellen A. Underwood, Yihao Zhu, G. Koley, T. Crawford, Jason R. Hattrick-Simpers

Faculty Publications

A gradient annealing cell has been developed for the high-throughput study of thermalannealing effects on thin-film libraries in different environments. The inexpensive gradientannealing unit permits temperature gradients as large as 28 °C/mm and can accommodate samples ranging in length from 13 mm to 51 mm. The system was validated by investigating the effects of annealing temperature on the crystallinity, resistivity, and transparency of tin-doped indium oxide deposited on a glass substrate by magnetron sputtering. The unit developed in this work will permit the rapid optimization of materials properties such as crystallinity, homogeneity, and conductivity across a variety of applications.

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Three-Dimensional Engineered Matrix To Study Cancer Stem Cells And Tumorsphere Formation: Effect Of Matrix Modulus, Xiaoming Yang, Samaneh Kamali Sarvestani, Seyedsina Moeinzadeh, Xuezhong He, Esmaiel Jabbari Mar 2013

Three-Dimensional Engineered Matrix To Study Cancer Stem Cells And Tumorsphere Formation: Effect Of Matrix Modulus, Xiaoming Yang, Samaneh Kamali Sarvestani, Seyedsina Moeinzadeh, Xuezhong He, Esmaiel Jabbari

Faculty Publications

Maintenance of cancer stem cells (CSCs) is regulated by the tumor microenvironment. Synthetic hydrogels provide the flexibility to design three-dimensional (3D) matrices to isolate and study individual factors in the tumor microenvironment. The objective of this work was to investigate the effect of matrix modulus on tumorsphere formation by breast cancer cells and maintenance of CSCs in an inert microenvironment without the interference of other factors. In that regard, 4T1 mouse breast cancer cells were encapsulated in inert polyethylene glycol diacrylate hydrogels and the effect of matrix modulus on tumorsphere formation and expression of CSC markers was investigated. The gel …

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Entropic Depletion Of Dna In Triangular Nanochannels, Wesley F. Reinhart, Douglas R. Tree, Kevin D. Dorfman Mar 2013

Entropic Depletion Of Dna In Triangular Nanochannels, Wesley F. Reinhart, Douglas R. Tree, Kevin D. Dorfman

Faculty Publications

Using Monte Carlo simulations of a touching-bead model of double-stranded DNA, we show that DNA extension is enhanced in isosceles triangular nanochannels (relative to a circular nanochannel of the same effective size) due to entropic depletion in the channel corners. The extent of the enhanced extension depends non-monotonically on both the accessible area of the nanochannel and the apex angle of the triangle. We also develop a metric to quantify the extent of entropic depletion, thereby collapsing the extension data for circular, square, and various triangular nanochannels onto a single master curve for channel sizes in the transition between the …

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A Steady-State Detection (Ssd) Algorithm To Detect Non-Stationary Drifts In Processes, Jeff Kelly, John Hedengren Mar 2013

A Steady-State Detection (Ssd) Algorithm To Detect Non-Stationary Drifts In Processes, Jeff Kelly, John Hedengren

Faculty Publications

Detecting windows or intervals of when a continuous process is operating in a state of steadiness is useful especially when steady-state models are being used to optimize the process or plant on-line or in real-time. The term steady-state implies that the process is operating around some stable point or within some stationary region where it must be assumed that the accumulation or rate-of-change of material, energy and momentum is statistically insignificant or negligible. This new approach is to assume the null-hypothesis that the process is stationary about its mean subject to independent and identically distributed random error or shocks (white-noise) …

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Biparametric Analyses Of Charge Trapping In Cd0.9Zn0.1Te Based Virtual Frisch Grid Detectors, S. K. Chaudhuri, K. J. Zavalla, R. M. Krishna, K. C. Mandal Feb 2013

Biparametric Analyses Of Charge Trapping In Cd0.9Zn0.1Te Based Virtual Frisch Grid Detectors, S. K. Chaudhuri, K. J. Zavalla, R. M. Krishna, K. C. Mandal

Faculty Publications

No abstract provided.

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Optical Down-Conversion In Doped Znse:Tb3+ Nanocrystals, Sandip Das, K. C. Mandal Feb 2013

Optical Down-Conversion In Doped Znse:Tb3+ Nanocrystals, Sandip Das, K. C. Mandal

Faculty Publications

No abstract provided.

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Insertion Of Lithium Ions Into Tio2 (Rutile) Crystals: An Electron Paramagnetic Resonance Study Of The Li-Associated Ti3+ Small Polaron, A. T. Brant, Nancy C. Giles, Larry E. Halliburton Feb 2013

Insertion Of Lithium Ions Into Tio2 (Rutile) Crystals: An Electron Paramagnetic Resonance Study Of The Li-Associated Ti3+ Small Polaron, A. T. Brant, Nancy C. Giles, Larry E. Halliburton

Faculty Publications

Electron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR) are used to identify a Ti3+-Li+ complex in TiO2 crystals having the rutile structure. This defect consists of an interstitial Li+ ion adjacent to a substitutional Ti3+ ion (the unpaired electron on the Ti3+ ion provides charge compensation for the Li+ ion). The neutral Ti3+-Li+ complex is best described as a donor-bound small polaron and is similar in structure to the recently reported neutral fluorine and hydrogen donors in TiO2 (rutile). Lithium ions are diffused into the crystals at …

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Visual Homing With A Pan-Tilt Based Stereo Camera, Paramesh Nirmal, Damian M. Lyons Feb 2013

Visual Homing With A Pan-Tilt Based Stereo Camera, Paramesh Nirmal, Damian M. Lyons

Faculty Publications

Visual homing is a navigation method based on comparing a stored image of the goal location and the current image (current view) to determine how to navigate to the goal location. It is theorized that insects, such as ants and bees, employ visual homing methods to return to their nest [1]. Visual homing has been applied to autonomous robot platforms using two main approaches: holistic and feature-based. Both methods aim at determining distance and direction to the goal location. Navigational algorithms using Scale Invariant Feature Transforms (SIFT) have gained great popularity in the recent years due to the robustness of …

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Objectives And Constraints For Wind Turbine Optimization, Andrew Ning, Rick Damiani, Patrick Moriarty Feb 2013

Objectives And Constraints For Wind Turbine Optimization, Andrew Ning, Rick Damiani, Patrick Moriarty

Faculty Publications

Efficient extraction of wind energy is a complex multidisciplinary process. This paper examines common objectives used in wind turbine optimization problems. The focus is not on the specific optimized designs, but rather on understanding when certain objectives and constraints are necessary, and what their limitations are. Maximizing annual energy production, or even using sequential aero/structural optimization, is shown to be significantly suboptimal compared to integrated aero/structural metrics. Minimizing the ratio of turbine mass to annual energy production can be effective for fixed rotor diameter designs, as long as the tower mass is estimated carefully. For variable diameter designs, the predicted …

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Guided Wave-Based J-Integral Estimation For Dynamic Stress Intensity Factors Using 3d Scanning Laser Doppler Vibrometry, J. Ayers, Christopher Todd Owen, Eric D. Swenson, Anindya Ghoshal, V. Weiss Jan 2013

Guided Wave-Based J-Integral Estimation For Dynamic Stress Intensity Factors Using 3d Scanning Laser Doppler Vibrometry, J. Ayers, Christopher Todd Owen, Eric D. Swenson, Anindya Ghoshal, V. Weiss

Faculty Publications

The application of guided waves to interrogate remote areas of structural components has been researched extensively in characterizing damage. However, there exists a sparsity of work in using piezoelectric transducer-generated guided waves as a method of assessing stress intensity factors (SIF). This quantitative information enables accurate estimation of the remaining life of metallic structures exhibiting cracks, such as military and commercial transport vehicles. The proposed full wavefield approach, based on 3D laser vibrometry and piezoelectric transducer-generated guided waves, provides a practical means for estimation of dynamic stress intensity factors (DSIF) through local strain energy mapping via the J-integral. Strain energies …

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Experimental Determination Of Electron-Hole Pair Creation Energy In 4h-Sic Epitaxial Layer: An Absolute Calibration Approach, S. K. Chaudhuri, K. J. Zavalla, K. C. Mandal Jan 2013

Experimental Determination Of Electron-Hole Pair Creation Energy In 4h-Sic Epitaxial Layer: An Absolute Calibration Approach, S. K. Chaudhuri, K. J. Zavalla, K. C. Mandal

Faculty Publications

No abstract provided.

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Exploring The Mechanisms Of Dna Hybridization On A Surface, Terry J. Schmitt, J Brandon Rogers, Thomas A. Knotts Iv Jan 2013

Exploring The Mechanisms Of Dna Hybridization On A Surface, Terry J. Schmitt, J Brandon Rogers, Thomas A. Knotts Iv

Faculty Publications

DNA microarrays are a potentially disruptive technology in the medical field, but their use in such settings is limited by poor reliability. Microarrays work on the principle of hybridization and can only be as reliable as this process is robust, yet little is known at the molecular level about how the surface affects the hybridization process. This work uses advanced molecular simulation techniques and an experimentally parameterized coarse-grain model to determine the mechanism by which hybridization occurs on surfaces. The results show that hybridization proceeds through a mechanism where the untethered (target) strand often flips orientation. For evenly lengthed strands, …

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Interfacial Bonding And Electronic Structure Of Hfo2/Gasb Interfaces: A First-Principles Study, Ka Xiong, Wei-Hua Wang, Dmitry Zhernokletov, Santosh Kc, Roberto Longo, R. Wallace, Kyeongjae Cho Jan 2013

Interfacial Bonding And Electronic Structure Of Hfo2/Gasb Interfaces: A First-Principles Study, Ka Xiong, Wei-Hua Wang, Dmitry Zhernokletov, Santosh Kc, Roberto Longo, R. Wallace, Kyeongjae Cho

Faculty Publications

The interfacial bonding and electronic structure of HfO2/GaSb interfaces has been investigated through first principles calculations. The calculated electronic structures of these interfaces reveal that some O-rich interfaces are semiconducting interfaces without any gap states. In contrast, for the interfaces with lower interfacial O content, gap states appear in the GaSb band gap, close to the conduction band. The valence band offsets are found to vary from 2.2 eV to 3.6 eV, depending on the interfacial O content. Our results suggest that GaSb is a suitable material to form high quality interface with HfO2.

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Hydrophobic Hydrogel Caged H3Po4 As A New Class Of High-Temperature Proton Exchange Membranes With Enhanced Acid Retention, Qunwei Tang, Guoging Qian, Kevin Huang Jan 2013

Hydrophobic Hydrogel Caged H3Po4 As A New Class Of High-Temperature Proton Exchange Membranes With Enhanced Acid Retention, Qunwei Tang, Guoging Qian, Kevin Huang

Faculty Publications

We herein report a new class of high-temperature proton exchange membranes comprised of poly(acrylic acid-graft-hexadecyltrimethylammonium bromide) (PAA-g-CTAB) or poly(acrylic acid)-graft-poly(ethylene glycol) (PAA-g-PEG) hydrophobic hydrogel caged H3PO4. The membranes exhibit reasonable proton conductivity, enhanced H3PO4 retention ability and low solubility in water, making them promising as potential high performance and robust electrolytes for high-temperature proton exchange membrane fuel cells. Although the proton conductivity is still lower than that of H3PO4 doped PBI membranes, the new concept provides a different approach to proton exchange membranes for acid retention.

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Efficient Space Dedication To Bus Rapid Transit Or Light Rail Systems, Jacob Tsao, A Pratama Jan 2013

Efficient Space Dedication To Bus Rapid Transit Or Light Rail Systems, Jacob Tsao, A Pratama

Faculty Publications

Dedicating two lanes and passenger platforms to transit typically requires taking the same space away from general use. This may affect public support. This paper proposes efficient geometric configurations for a two-dedicated-lane BRT or light rail system that requires a minimum amount of right-of-way along a busy commute arterial. In many current busy commute corridors, a significant part of the street median is underused or unused for traffic purposes. The efficiency is achieved ainly by using the street median between a left-turn lane and its counterpart located at the intersection on the other end of the same street section and …

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The Influence Of Personality And Ability On Undergraduate Teamwork And Team Performance, Jinny Rhee, David W. Parent, Anuradha Basu Jan 2013

The Influence Of Personality And Ability On Undergraduate Teamwork And Team Performance, Jinny Rhee, David W. Parent, Anuradha Basu

Faculty Publications

The ability to work effectively on a team is highly valued by employers, and collaboration among students can lead to intrinsic motivation, increased persistence, and greater transferability of skills. Moreover, innovation often arises from multidisciplinary teamwork. The influence of personality and ability on undergraduate teamwork and performance is not comprehensively understood. An investigation was undertaken to explore correlations between team outcomes, personality measures and ability in an undergraduate population. Team outcomes included various self-, peer- and instructor ratings of skills, performance, and experience. Personality measures and ability involved the Five-Factor Model personality traits and GPA. Personality, GPA, and teamwork survey …

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Simulation Studying Effects Of Multiple Primary Aberrations On Donut-Shaped Gaussian Beam, Chen Zhang, K. Wang, J. Bai, Y. Liu, Guiren Wang Jan 2013

Simulation Studying Effects Of Multiple Primary Aberrations On Donut-Shaped Gaussian Beam, Chen Zhang, K. Wang, J. Bai, Y. Liu, Guiren Wang

Faculty Publications

In this paper, we demonstrate the variation of donut-shaped depletion pattern which influenced by multiple primary aberrations. The simulation is base on a common stimulation emission of depletion (STED) system composed by Gaussian laser and vortex phase plate. The simulation results are helpful guidelines for analyzing the aberration of depletion patterns in real situations.

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Wave Propagation In Metamaterial Using Multiscale Resonators By Creating Local Anisotropy, Raiz U. Ahmed, Sourav Banerjee Jan 2013

Wave Propagation In Metamaterial Using Multiscale Resonators By Creating Local Anisotropy, Raiz U. Ahmed, Sourav Banerjee

Faculty Publications

Directional guiding, passing or stopping of elastic waves through engineered materials have many applications to the engineering fields. Recently, such engineered composite materials received great attention by the broader research community. In elastic waves, the longitudinal and transverse motion of material particles are coupled, which exhibits richer physics and demands greater attention than electromagnetic waves and acoustic waves in fluids. Waves in periodic media exhibit the property of Bragg scattering and create frequency band gaps in which the energy propagation is prohibited. However, in addition to the Bragg scattering, it has been found that local resonance of artificially designed resonators …

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Nanopillar Array With A Λ/11 Diameter Fabricated By A Kind Of Visible Cw Laser Direct Lithography System, Chen Zhang, K. Wang, J. Bai, S. Wang, W. Zhao, F. Yang, C. Gu, Guiren Wang Jan 2013

Nanopillar Array With A Λ/11 Diameter Fabricated By A Kind Of Visible Cw Laser Direct Lithography System, Chen Zhang, K. Wang, J. Bai, S. Wang, W. Zhao, F. Yang, C. Gu, Guiren Wang

Faculty Publications

Nanoscale functional structures are indispensable elements in many fields of modern science. In this paper, nanopillar array with a pillar diameter far smaller than Abbe's diffraction limit is realized by a new kind of continuous wave (CW) laser direct lithography technology. With atomic force microscopy technology, the average diameter of nanopillars on thin OIR906 photoresist film is about 65 nm and the smallest diameter is 48 nm, which is about 1/11 of the incident laser wavelength. Also, the influences of coma and astigmatism effects to the shape and size of nanopillar are numerically simulated by utilizing vector integral. As far …

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