Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Missouri University of Science and Technology

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 7081 - 7110 of 33628

Full-Text Articles in Entire DC Network

Sensor-Enhanced Analysis And Behavior Of Steel Beams In Fire, Genda Chen Oct 2018

Sensor-Enhanced Analysis And Behavior Of Steel Beams In Fire, Genda Chen

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Traditionally, strain data are difficult, if not impossible, to obtain from steel structures in fire due to their harsh environment and temperature measurements are limited to the locations of thermocouples. This paper presents high-temperature measurements using a Brillouin scattering based (distributed) fiber optic sensor and the application of the measured temperatures and material parameters recommended in building codes into the enhanced thermo-mechanical analysis of simply-supported steel beams subjected to combined thermal and loading effects. The distributed temperature sensor captures detailed, non-uniform temperature distributions that are compared locally with thermocouple measurements by less than 5% at a 95% confidence level. The …


Polymer Coated Gold-Ferric Oxide Superparamagnetic Nanoparticles For Theranostic Applications, Muhammad Raisul Abedin, Siddesh Umapathi, Harika Mahendrakar, Tunyaboon Laemthong, Holly Coleman, Denise Muchangi, Santimukul Santra, Manashi Nath, Sutapa Barua Oct 2018

Polymer Coated Gold-Ferric Oxide Superparamagnetic Nanoparticles For Theranostic Applications, Muhammad Raisul Abedin, Siddesh Umapathi, Harika Mahendrakar, Tunyaboon Laemthong, Holly Coleman, Denise Muchangi, Santimukul Santra, Manashi Nath, Sutapa Barua

Chemistry Faculty Research & Creative Works

Background: Engineered inorganic nanoparticles (NPs) are essential components in the development of nanotechnologies. For applications in nanomedicine, particles need to be functionalized to ensure a good dispersibility in biological fluids. In many cases however, functionalization is not sufficient: the particles become either coated by a corona of serum proteins or precipitate out of the solvent. We show that by changing the coating of magnetic iron oxide NPs using poly-l-lysine (PLL) polymer the colloidal stability of the dispersion is improved in aqueous solutions including water, phosphate buffered saline (PBS), PBS with 10% fetal bovine serum (FBS) and cell culture medium, and …


The Bridge Newsletter Winter 2018, Missouri University Of Science And Technology Oct 2018

The Bridge Newsletter Winter 2018, Missouri University Of Science And Technology

The Bridge Newsletter

-Pouring the cornerstone for the ACML
-Showalter selected as Kiewit Faculty Scholar
-Ma tests a low-cost method of strengthening concrete


Ultra-Thin Coating And Three-Dimensional Electrode Structures To Boosted Thick Electrode Lithium-Ion Battery Performance, Jie Li, Yan Gao, Xinhua Liang, Jonghyun Park Oct 2018

Ultra-Thin Coating And Three-Dimensional Electrode Structures To Boosted Thick Electrode Lithium-Ion Battery Performance, Jie Li, Yan Gao, Xinhua Liang, Jonghyun Park

Chemical and Biochemical Engineering Faculty Research & Creative Works

This paper reports a multiscale controlled three‐dimensional (3D) electrode structure to boost the battery performance for thick electrode batteries with LiMn1.5Ni0.5O4 as cathode material, which exhibits a high areal capacity (3.5 mAh/cm2) along with a high specific capacity (130 mAh/g). This excellent battery performance is achieved by a new concept of cell electrode fabrication, which simultaneously controls the electrode structure in a multiscale manner to address the key challenges of the material. Particles with ultrathin conformal coating layers are prepared through atomic layer deposition followed by a nanoscale‐controlled, thermal diffusion doping. The particles …


Gw170817: Measurements Of Neutron Star Radii And Equation Of State, B. P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Oct 2018

Gw170817: Measurements Of Neutron Star Radii And Equation Of State, B. P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

On 17 August 2017, the LIGO and Virgo observatories made the first direct detection of gravitational waves from the coalescence of a neutron star binary system. The detection of this gravitational-wave signal, GW170817, offers a novel opportunity to directly probe the properties of matter at the extreme conditions found in the interior of these stars. The initial, minimal-assumption analysis of the LIGO and Virgo data placed constraints on the tidal effects of the coalescing bodies, which were then translated to constraints on neutron star radii. Here, we expand upon previous analyses by working under the hypothesis that both bodies were …


Scholars' Mine Quick Facts September 2018, Nancy S. Krost Sep 2018

Scholars' Mine Quick Facts September 2018, Nancy S. Krost

Scholars’ Mine Statistics

Scholars' Mine Quick Facts are monthly reports of downloads, page hits, and other information about works in the institutional repository of Missouri S&T. A map with downloads by region is also included.


From Tag To Protect: A Tag-Driven Policy Recommender System For Image Sharing, Anna Cinzia Squicciarini, Andrea Novelli, Dan Lin, Cornelia Caragea, Haoti Zhong Sep 2018

From Tag To Protect: A Tag-Driven Policy Recommender System For Image Sharing, Anna Cinzia Squicciarini, Andrea Novelli, Dan Lin, Cornelia Caragea, Haoti Zhong

Computer Science Faculty Research & Creative Works

Sharing images on social network sites has become a part of daily routine for more and more online users. However, in face of the considerable number of images shared online, it is not a trivial task for a person to manually configure proper privacy settings for each of the images that he/she uploaded. The lack of proper privacy protection during image sharing could raise many potential privacy breaches of people's private lives that they are not aware of. In this work, we propose a privacy setting recommender system to help people effortlessly set up the privacy settings for their online …


Novel Porous Polymer Compositions For The Synthesis Of Monolithic Bimodal Microporous/Macroporous Carbon Compositions Useful For Selective Co₂ Sequestration, Nicholas Leventis, Chariklia Sotiriou-Leventis, Malik Adnan Saeed Sep 2018

Novel Porous Polymer Compositions For The Synthesis Of Monolithic Bimodal Microporous/Macroporous Carbon Compositions Useful For Selective Co₂ Sequestration, Nicholas Leventis, Chariklia Sotiriou-Leventis, Malik Adnan Saeed

Chemistry Faculty Research & Creative Works

The present invention discloses novel porous polymeric compositions comprising random copolymers of amides, imides, ureas, and carbamic-anhydrides, useful for the synthesis of monolithic bimodal microporous/macroporous carbon aerogels. It also discloses methods for producing said microporous/macroporous carbon aerogels by the reaction of a polyisocyanate compound and a polycarboxylic acid compound, followed by pyrolytic carbonization, and by reactive etching with CO2 at elevated temperatures. Also disclosed are methods for using the microporous/macroporous carbon aerogels in the selective capture and sequestration of carbon dioxide.


Ultralow Dispersion Multicomponent Thin-Film Chalcogenide Glass For Broadband Gradient-Index Optics, Myungkoo Kang, Andrew M. Swisher, Alexej V. Pogrebnyakov, Liu Liu, Andrew Kirk, Stephen Aiken, Laura Sisken, Charmayne Lonergan, Justin Cook, Teodor Malendevych, Fedor Kompan, Ivan Divliansky, Leonid B. Glebov, Martin C. Richardson, Clara Rivero-Baleine, Carlo G. Pantano Sep 2018

Ultralow Dispersion Multicomponent Thin-Film Chalcogenide Glass For Broadband Gradient-Index Optics, Myungkoo Kang, Andrew M. Swisher, Alexej V. Pogrebnyakov, Liu Liu, Andrew Kirk, Stephen Aiken, Laura Sisken, Charmayne Lonergan, Justin Cook, Teodor Malendevych, Fedor Kompan, Ivan Divliansky, Leonid B. Glebov, Martin C. Richardson, Clara Rivero-Baleine, Carlo G. Pantano

Materials Science and Engineering Faculty Research & Creative Works

A novel photothermal process to spatially modulate the concentration of sub-wavelength, high-index nanocrystals in a multicomponent Ge-As-Pb-Se chalcogenide glass thin film resulting in an optically functional infrared grating is demonstrated. The process results in the formation of an optical nanocomposite possessing ultralow dispersion over unprecedented bandwidth. The spatially tailored index and dispersion modification enables creation of arbitrary refractive index gradients. Sub-bandgap laser exposure generates a Pb-rich amorphous phase transforming on heat treatment to high-index crystal phases. Spatially varying nanocrystal density is controlled by laser dose and is correlated to index change, yielding local index modification to ≈+0.1 in the mid-infrared.


Toward Autonomous Wall-Climbing Robots For Inspection Of Concrete Bridges And Tunnels, Jizhong Xiao Sep 2018

Toward Autonomous Wall-Climbing Robots For Inspection Of Concrete Bridges And Tunnels, Jizhong Xiao

INSPIRE Archived Webinars

In addition to visual inspection for surface flaws, inspectors are often required to detect subsurface defects (e.g., delamination and voids) using nondestructive evaluation (NDE) instruments, such as ground penetration radar (GPR) and impact sounding device, in order to determine the structural integrity of bridges and tunnels. In these cases, access to critical locations for reliable and safe inspections is a challenge.

Since 2002, Dr. Jizhong Xiao’s group has developed four generations of wall-climbing robots for NDE inspection of bridges and tunnels. These robots combine the advantages of aerodynamic attraction and suction to achieve a desirable balance of strong adhesion and …


September 2018 Cafe Newsletter, Center For Advancing Faculty Excellence Sep 2018

September 2018 Cafe Newsletter, Center For Advancing Faculty Excellence

CAFE Faculty Newsletters

No abstract provided.


Signatures Of Autoionization In The Angular Electron Distribution In Two-Photon Double Ionization Of Ar, S. Augustin, Michael Schulz, G. Schmid, K. Schnorr, E. V. Gryzlova, H. Lindenblatt, S. Meister, Y. F. Liu, F. Trost, L. Fechner, A. N. Grum-Grzhimailo, S. M. Burkov, M. Braune, R. Treusch Sep 2018

Signatures Of Autoionization In The Angular Electron Distribution In Two-Photon Double Ionization Of Ar, S. Augustin, Michael Schulz, G. Schmid, K. Schnorr, E. V. Gryzlova, H. Lindenblatt, S. Meister, Y. F. Liu, F. Trost, L. Fechner, A. N. Grum-Grzhimailo, S. M. Burkov, M. Braune, R. Treusch

Physics Faculty Research & Creative Works

A kinematically complete experiment on two-photon double ionization of Ar by free-electron laser radiation with a photon energy of 27.93 eV was performed. The electron energy spectra show that double ionization is dominated by the sequential process. Comparison of the electron angular distributions to our data for single ionization and to theory confirms that even in the sequential process the electrons from both ionization steps are correlated with each other through polarization of the intermediate Ar+ state. Furthermore, a very important role of autoionization in both ionization steps is found.


Faculty Senate Minutes September 13, 2018, Missouri University Of Science And Technology Faculty Senate Sep 2018

Faculty Senate Minutes September 13, 2018, Missouri University Of Science And Technology Faculty Senate

Minutes & Agendas

No abstract provided.


Decoupling Of Multi-Element Mimo Antennas, Min Li, L. (Lijun) J. Jiang Sep 2018

Decoupling Of Multi-Element Mimo Antennas, Min Li, L. (Lijun) J. Jiang

Electrical and Computer Engineering Faculty Research & Creative Works

An efficient decoupling technique for multi-element MIMO antennas is proposed in this paper. A general model of using parasitic decoupling structure (PDS) to satisfy the criterions derived from antenna impedances for perfect isolation is presented. A prototype of three monopole antennas is realized on a Rogers PCB for demonstration purpose. The simulation results show that good impedance matching and high port isolation are achieved simultaneously.


Solid State Nmr Spectroscopy/Imaging In Situ Measuring Devices And Methods For Calibration And Determining One Or More Quantitative Properties Of A Target Sample, Lingyu Chi, Ming Huang, Rex E. Gerald, Klaus Woelk Sep 2018

Solid State Nmr Spectroscopy/Imaging In Situ Measuring Devices And Methods For Calibration And Determining One Or More Quantitative Properties Of A Target Sample, Lingyu Chi, Ming Huang, Rex E. Gerald, Klaus Woelk

Chemistry Faculty Research & Creative Works

In situ measuring devices, methods of making the same, and methods of using the same are provided herein. The in situ measuring devices can include a capillary tube having a reference material sealed inside the capillary tube, where the capillary tube is positioned inside of a solid state or MAS NMR rotor. A target sample can also be positioned in the interior of the solid state or MAS NMR rotor but is sequestered from the reference material by a capillary tube wall. The in situ measuring devices can be used in solid state MAS NMR spectroscopy to quantify one or …


Solid State Nmr Spectroscopy/Imaging In Situ Measuring Devices And Methods For Calibration And Determining One Or More Quantitative Properties Of A Target Sampleabstract, Lingyu Chi, Ming Huang, R. Gerald Ii, Klaus Woelk Sep 2018

Solid State Nmr Spectroscopy/Imaging In Situ Measuring Devices And Methods For Calibration And Determining One Or More Quantitative Properties Of A Target Sampleabstract, Lingyu Chi, Ming Huang, R. Gerald Ii, Klaus Woelk

Chemistry Faculty Research & Creative Works

In situ measuring devices, methods of making the same, and methods of using the same are provided herein. The in situ measuring devices can include a capillary tube having a reference material sealed inside the capillary tube, where the capillary tube is positioned inside of a solid state or MAS NMR rotor. A target sample can also be positioned in the interior of the solid state or MAS NMR rotor but is sequestered from the reference material by a capillary tube wall. The in situ measuring devices can be used in solid state MAS NMR spectroscopy to quantify one or …


A Further Extension Of The Extended Riemann-Liouville Fractional Derivative Operator, Martin Bohner, Gauhar Rahman, Shahid Mubeen, Kottakkaran Sooppy Nisar Sep 2018

A Further Extension Of The Extended Riemann-Liouville Fractional Derivative Operator, Martin Bohner, Gauhar Rahman, Shahid Mubeen, Kottakkaran Sooppy Nisar

Mathematics and Statistics Faculty Research & Creative Works

The main objective of this paper is to establish the extension of an extended fractional derivative operator by using an extended beta function recently defined by Parmar et al. by considering the Bessel functions in its kernel. We also give some results related to the newly defined fractional operator, such as Mellin transform and relations to extended hypergeometric and Appell's function via generating functions.


University Committee For Assistance, Response, And Evaluation (Ucare), Missouri University Of Science And Technology. Counseling Services Sep 2018

University Committee For Assistance, Response, And Evaluation (Ucare), Missouri University Of Science And Technology. Counseling Services

General Resources

Members of the campus community are encouraged to contact UCARE when concerned about a student, regardless of how insignificant the concern may seem. Doing so assists UCARE in collecting various pieces of the puzzle to connect the student with appropriate resources and support. Faculty can report their concerns online at UCARE or by contacting the Care Coordinator, Krista Morris-Lehman at [email protected] or 341-4211. More information about UCARE and care coordination services can be found at Care Coordination.


Missouri S&T Magazine Fall/Winter 2018, Missouri S&T Marketing And Communications Department, Miner Alumni Association Sep 2018

Missouri S&T Magazine Fall/Winter 2018, Missouri S&T Marketing And Communications Department, Miner Alumni Association

Missouri S&T Magazine

No abstract provided.


Multi-Task Allocation In Mobile Crowd Sensing With Individual Task Quality Assurance, Jiangtao Wang, Yasha Wang, Daqing Zhang, Feng Wang, Haoyi Xiong, Chao Chen, Qin Lv, Zhaopeng Qiu Sep 2018

Multi-Task Allocation In Mobile Crowd Sensing With Individual Task Quality Assurance, Jiangtao Wang, Yasha Wang, Daqing Zhang, Feng Wang, Haoyi Xiong, Chao Chen, Qin Lv, Zhaopeng Qiu

Computer Science Faculty Research & Creative Works

Task allocation is a fundamental research issue in mobile crowd sensing. While earlier research focused mainly on single tasks, recent studies have started to investigate multi-task allocation, which considers the interdependency among multiple tasks. A common drawback shared by existing multi-task allocation approaches is that, although the overall utility of multiple tasks is optimized, the sensing quality of individual tasks may become poor as the number of tasks increases. To overcome this drawback, we re-define the multi-task allocation problem by introducing task-specific minimal sensing quality thresholds, with the objective of assigning an appropriate set of tasks to each worker such …


Optical-Fiber-Based Smart Concrete Thermal Integrity Profiling: An Example Of Concrete Shaft, Ruoyu Zhong, Ruichang Guo, Wen Deng Sep 2018

Optical-Fiber-Based Smart Concrete Thermal Integrity Profiling: An Example Of Concrete Shaft, Ruoyu Zhong, Ruichang Guo, Wen Deng

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Concrete is currently the most widely used construction material in the world. The integrity of concrete during the pouring process could greatly affect its engineering performance. Taking advantage of heat production during the concrete curing process, we propose an optical-fiber-based thermal integrity profiling (TIP) method which can provide a comprehensive and accurate evaluation of the integrity of concrete immediately after its pouring. In this paper, we use concrete shaft as an example to conduct TIP by using the optical fiber as a temperature sensor which can obtain high spatial resolution temperature data. Our method is compared with current thermal infrared …


Rheological Properties Of Warm Mix Asphalt Binders And Warm Mix Asphalt Binders Containing Polyphosphoric Acid, Jun Liu, Kezhen Yan, Jenny Liu Sep 2018

Rheological Properties Of Warm Mix Asphalt Binders And Warm Mix Asphalt Binders Containing Polyphosphoric Acid, Jun Liu, Kezhen Yan, Jenny Liu

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper presents the laboratory investigation of properties of warm mix asphalt (WMA) binders and WMA binders containing polyphosphoric acid (PPA).Two types of warm mix additives were used to produce the WMA binders. Superpave tests were carried out on original and short-term aged binders through the rotational viscometer, the dynamic shear rheometer (DSR), and the bending beam rheometer (BBR). The results indicated that the WMA binders with different warm mix additives showed different viscosity values, however, the addition of PPA remarkably increased the viscosity values of these two kinds of WMA binders used, in the present study, to a similar …


Numerical Simulation Study On Miscible Eor Techniques For Improving Oil Recovery In Shale Oil Reservoirs, Dheiaa Alfarge, Mingzhen Wei, Baojun Bai Sep 2018

Numerical Simulation Study On Miscible Eor Techniques For Improving Oil Recovery In Shale Oil Reservoirs, Dheiaa Alfarge, Mingzhen Wei, Baojun Bai

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Shale formations in North America such as Bakken, Niobrara, and Eagle Ford have huge oil in place, 100—900 billion barrels of oil in Bakken only. However, the predicted primary recovery is still below 10%. Therefore, seeking for techniques to enhance oil recovery in these complex plays is inevitable. Although most of the previous studies in this area recommended that CO2 would be the best EOR technique to improve oil recovery in these formations, pilot tests showed that natural gases performance clearly exceeds CO2 performance in the field scale. In this paper, two different approaches have been integrated to …


Metaphysics Or Metaphors For The Anthropocene? Scientific Naturalism And The Agency Of Things, Patrick Gamez Sep 2018

Metaphysics Or Metaphors For The Anthropocene? Scientific Naturalism And The Agency Of Things, Patrick Gamez

Arts, Languages and Philosophy Faculty Research & Creative Works

In this paper, I provide the outlines of an alternative meta philosophical orientation for Continental philosophy, namely, a form of scientific naturalism that has proximate roots in the work of Bachelard and Althusser. I describe this orientation as an "alternative" insofar as it provides a framework for doing justice to some of the motivations behind the recent revival of metaphysics in Continental philosophy, in particular its ecological-ethical motivations. In the second section of the paper, I demonstrate how ecological-ethical issues motivate new metaphysicians like Bruno Latour, Jane Bennett, Timothy Morton, Ian Bogost, and Graham Harman to impute to objects real …


Tunnel Diode Resonator For Precision Magnetic Susceptibility Measurements In A Mk Temperature Range And Large Dc Magnetic Fields, Hyunsoo Kim, M. A. Tanatar, R. Prozorov Sep 2018

Tunnel Diode Resonator For Precision Magnetic Susceptibility Measurements In A Mk Temperature Range And Large Dc Magnetic Fields, Hyunsoo Kim, M. A. Tanatar, R. Prozorov

Physics Faculty Research & Creative Works

Precision radio-frequency measurements of the magnetic susceptibility using the tunnel diode resonator (TDR) technique are used to study the delicate effects in magnetic and superconducting materials. High resolution (in ppb range) measurements are particularly important for studies of the London and Campbell penetration depths in a superconductor and for the investigation of magnetic transitions in (anti)ferromagnets. Due to the small rf magnetic-excitation in a mOe range, the TDR is especially useful at low-temperatures in a mK range, if Joule heating generated in the TDR circuitry is efficiently removed and the circuit is stabilized with sub-mK precision. Unfortunately, the circuit has …


Ultrafast X-Ray Imaging Of Laser-Metal Additive Manufacturing Processes, Niranjan D. Parab, Cang Zhao, Ross Cunningham, Luis I. Escano, Kamel Fezzaa, Wes Everhart, Anthony D. Rollett, Lianyi Chen, Tao Sun Sep 2018

Ultrafast X-Ray Imaging Of Laser-Metal Additive Manufacturing Processes, Niranjan D. Parab, Cang Zhao, Ross Cunningham, Luis I. Escano, Kamel Fezzaa, Wes Everhart, Anthony D. Rollett, Lianyi Chen, Tao Sun

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The high-speed synchrotron X-ray imaging technique was synchronized with a custom-built laser-melting setup to capture the dynamics of laser powder-bed fusion processes in situ. Various significant phenomena, including vapor-depression and melt-pool dynamics and powder-spatter ejection, were captured with high spatial and temporal resolution. Imaging frame rates of up to 10 MHz were used to capture the rapid changes in these highly dynamic phenomena. At the same time, relatively slow frame rates were employed to capture large-scale changes during the process. This experimental platform will be vital in the further understanding of laser additive manufacturing processes and will be particularly …


Deformation Of A Ferrofluid Droplet In Simple Shear Flows Under Uniform Magnetic Fields, Md Rifat Hassan, Jie Zhang, Cheng Wang Sep 2018

Deformation Of A Ferrofluid Droplet In Simple Shear Flows Under Uniform Magnetic Fields, Md Rifat Hassan, Jie Zhang, Cheng Wang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We numerically investigate the deformation and orientation of a ferrofluid droplet in a simple shear flow under a uniform magnetic field. The numerical simulation is based on the finite element method and couples the magnetic and flow fields. A level set method is used to model the dynamic motion of the droplet interface. Systematic numerical simulations are used to assess the effects of the direction and the strength of the magnetic field. Focusing on low Reynolds number flows (Re ≲ 0.02), the numerical results indicate that at a small capillary number (Ca ≈ 0.02), the magnetic field dominates over the …


Locomotion Of A Cylindrical Rolling Robot With A Shape Changing Outer Surface, Michael G. Puopolo, Jamey D. Jacob, Emilio Gabino Sep 2018

Locomotion Of A Cylindrical Rolling Robot With A Shape Changing Outer Surface, Michael G. Puopolo, Jamey D. Jacob, Emilio Gabino

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A cylindrical rolling robot is developed that generates roll torque by changing the shape of its flexible, elliptical outer surface whenever one of four elliptical axes rotates past an inclination called trigger angle. The robot is equipped with a sensing/control system by which it measures angular position and angular velocity, and computes error with respect to a desired step angular velocity profile. When shape change is triggered, the newly assumed shape of the outer surface is determined according to the computed error. A series of trial rolls is conducted using various trigger angles, and energy consumed by the actuation motor …


Electronic Fingerprints Of Cr And V Dopants In The Topological Insulator Sb₂Te₃, Wenhan Zhang, Damien West, Seng Huat Lee, Yunsheng Qiu, Cui-Zu Chang, Jagadeesh S. Moodera, Yew San Hor, Shengbai Zhang, Weida Wu Sep 2018

Electronic Fingerprints Of Cr And V Dopants In The Topological Insulator Sb₂Te₃, Wenhan Zhang, Damien West, Seng Huat Lee, Yunsheng Qiu, Cui-Zu Chang, Jagadeesh S. Moodera, Yew San Hor, Shengbai Zhang, Weida Wu

Physics Faculty Research & Creative Works

By combining scanning tunneling microscopy/spectroscopy and first-principles calculations, we systematically study the local electronic states of magnetic dopants V and Cr in the topological insulator (TI) Sb2Te3. Spectroscopic imaging shows diverse local defect states between Cr and V, which agree with our first-principle calculations. The unique spectroscopic features of V and Cr dopants provide electronic fingerprints for the codoped magnetic TI samples with the enhanced quantum anomalous Hall effect. Our results also facilitate the exploration of the underlying mechanism of the enhanced quantum anomalous Hall temperature in Cr/V codoped TIs.


Advanced Metal Oxides And Nitrides Thermoelectric Materials For Energy Harvesting, Yining Feng, Evan Witkoske, Elizabeth S. Bell, Yang Wang, Athanasios Tzempelikos, Ian T. Ferguson, Na Lu Sep 2018

Advanced Metal Oxides And Nitrides Thermoelectric Materials For Energy Harvesting, Yining Feng, Evan Witkoske, Elizabeth S. Bell, Yang Wang, Athanasios Tzempelikos, Ian T. Ferguson, Na Lu

Electrical and Computer Engineering Faculty Research & Creative Works

Metal oxides and nitrides are widely used in many applications as a result of their high mechanical, chemical, and electrical properties. In high temperature thermoelectric applications, oxides and nitrides exhibit high thermopower and thermal stability. Moreover, most oxides and nitrides are consisted of earth abundant elements, which are non-toxic, cost effective and easy for large-scale synthesis. In this article, we reviewed the recent advances of metal oxides and nitrides and their applications in thermoelectric. The materials that are examined include both p-type semiconductors (e.g. NaxCoO2, Ca3Co4O9, GaN) and n-type semiconductors (e.g. ZnO-based, …