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Articles 1 - 30 of 31
Full-Text Articles in Engineering
A Microfluidic Paper-Based Electrochemical Biosensor Array For Multiplexed Detection Of Metabolic Biomarkers, Chen Zhao, Martin M. Thuo, Xinyu Liu
A Microfluidic Paper-Based Electrochemical Biosensor Array For Multiplexed Detection Of Metabolic Biomarkers, Chen Zhao, Martin M. Thuo, Xinyu Liu
Martin M. Thuo
Paper-based microfluidic devices have emerged as simple yet powerful platforms for performing low-cost analytical tests. This paper reports a microfluidic paper-based electrochemical biosensor array for multiplexed detection of physiologically relevant metabolic biomarkers. Different from existing paper-based electrochemical devices, our device includes an array of eight electrochemical sensors and utilizes a handheld custom-made electrochemical reader (potentiostat) for signal readout. The biosensor array can detect several analytes in a sample solution and produce multiple measurements for each analyte from a single run. Using the device, we demonstrate simultaneous detection of glucose, lactate and uric acid in urine, with analytical performance comparable to …
Project Complexity Mapping In Five Dimensions For Complex Transportation Projects, Douglas D. Gransberg, Jennifer S. Shane, Carla Lopez Del Puerto
Project Complexity Mapping In Five Dimensions For Complex Transportation Projects, Douglas D. Gransberg, Jennifer S. Shane, Carla Lopez Del Puerto
Douglas D. Gransberg
Traditional three-dimensional project management theory is based on optimizing the cost-schedule-technical dimensions. Recent studies in the United Kingdom, Canada, and Australia have shown that the current project management body of knowledge may not be adequate to address interrelated and dependent variables encountered on complex projects. This paper reports the findings of an international research team’s detailed study of eighteen complex projects, which confirms the findings of the previous research and proposes a framework upon which a complex transportation project’s scope of work can be better conceptualized and a methodology to graphically display a project’s complexity in order to better understand …
Joint User Grouping And Linear Virtual Beamforming: Complexity, Algorithms And Approximation Bounds, Mingyi Hong, Zi Xu, Meisam Razaviyayn, Zhi-Quan Luo
Joint User Grouping And Linear Virtual Beamforming: Complexity, Algorithms And Approximation Bounds, Mingyi Hong, Zi Xu, Meisam Razaviyayn, Zhi-Quan Luo
Mingyi Hong
In a wireless system with a large number of distributed nodes, the quality of communication can be greatly improved by pooling the nodes to perform joint transmission/reception. In this paper, we consider the problem of optimally selecting a subset of nodes from potentially a large number of candidates to form a virtual multi-antenna system, while at the same time designing their joint linear transmission strategies. We focus on two specific application scenarios: 1) multiple single antenna transmitters cooperatively transmit to a receiver; 2) a single transmitter transmits to a receiver with the help of a number of cooperative relays. We …
Aerodynamic Simulation Of Vertical-Axis Wind Turbines, A. Korobenko, Ming-Chen Hsu, I. Akkerman, Y. Bazilevs
Aerodynamic Simulation Of Vertical-Axis Wind Turbines, A. Korobenko, Ming-Chen Hsu, I. Akkerman, Y. Bazilevs
Ming-Chen Hsu
Full-scale, 3D, time-dependent aerodynamics modeling and simulation of a Darrieus-type vertical-axis wind turbine (VAWT) is presented. The simulations are performed using a moving-domain finite-element-based ALE-VMS technique augmented with a sliding-interface formulation to handle the rotor-stator interactions present. We simulate a single VAWT using a sequence of meshes with increased resolution to assess the computational requirements for this class of problems. The computational results are in good agreement with experimental data. We also perform a computation of two side-by-side counterrotating VAWTs to illustrate how the ALE-VMS technique may be used for the simulation of multiple turbines placed in arrays.
Paramagnetic Ionic Liquids For Measurements Of Density Using Magnetic Levitation, David K. Bwambok, Martin M. Thuo, Manza B.J. Atkinson, Katherine A. Mirica, Nathan D. Shapiro, George M. Whitesides
Paramagnetic Ionic Liquids For Measurements Of Density Using Magnetic Levitation, David K. Bwambok, Martin M. Thuo, Manza B.J. Atkinson, Katherine A. Mirica, Nathan D. Shapiro, George M. Whitesides
Martin M. Thuo
Paramagnetic ionic liquids (PILs) provide new capabilities to measurements of density using magnetic levitation (MagLev). In a typical measurement, a diamagnetic object of unknown density is placed in a container containing a PIL. The container is placed between two magnets (typically NdFeB, oriented with like poles facing). The density of the diamagnetic object can be determined by measuring its position in the magnetic field along the vertical axis (levitation height, h), either as an absolute value or relative to internal standards of known density. For density measurements by MagLev, PILs have three advantages over solutions of paramagnetic salts in aqueous …
Joint Access Point Selection And Power Allocation For Uplink Wireless Networks, Mingyi Hong, Alfredo Garcia, Jorge Barrera, Stephen G. Wilson
Joint Access Point Selection And Power Allocation For Uplink Wireless Networks, Mingyi Hong, Alfredo Garcia, Jorge Barrera, Stephen G. Wilson
Mingyi Hong
We consider the distributed uplink resource allocation problem in a multi-carrier wireless network with multiple access points (APs). Each mobile user can optimize its own transmission rate by selecting a suitable AP and by controlling its transmit power. Our objective is to devise suitable algorithms by which mobile users can jointly perform these tasks in a distributed manner. Our approach relies on a game theoretic formulation of the joint power control and AP selection problem. In the proposed game, each user is a player with an associated strategy containing a discrete variable (the AP selection decision) and a continuous vector …
Distributed Linear Precoder Optimization And Base Station Selection For An Uplink Heterogeneous Network, Mingyi Hong, Zhi-Quan Luo
Distributed Linear Precoder Optimization And Base Station Selection For An Uplink Heterogeneous Network, Mingyi Hong, Zhi-Quan Luo
Mingyi Hong
In a heterogeneous wireless cellular network, each user may be covered by multiple access points such as macro/pico/relay/femto base stations (BS). An effective approach to maximize the sum utility (e.g., system throughput) in such a network is to jointly optimize users' linear procoders as well as their BS associations. In this paper, we first show that this joint optimization problem is NP-hard and thus is difficult to solve to global optimality. To find a locally optimal solution, we formulate the problem as a noncooperative game in which the users and the BSs both act as players. We introduce a set …
Extremes Of Nonlinear Vibration: Comparing Models Based On Moments, L-Moments, And Maximum Entropy, Steven R. Winterstein, Cameron A. Mackenzie
Extremes Of Nonlinear Vibration: Comparing Models Based On Moments, L-Moments, And Maximum Entropy, Steven R. Winterstein, Cameron A. Mackenzie
Cameron A. MacKenzie
Wind and wave loads on offshore structures show nonlinear effects, which require nonGaussian statistical models. Here we critically review the behavior of various nonGaussian models. We first survey moment-based models; in particular, the four-moment “Hermite” model, a cubic transformation often used in wind and wave applications. We then derive an “L-Hermite” model, an alternative cubic transformation calibrated by the response “L-moments” rather than its ordinary statistical moments. These L-moments have recently found increasing use, in part because they show less sensitivity to distribution tails than ordinary moments. We find here, however, that these L-moments may not convey sufficient information to …
Safety Impacts Of Signal-Warning Flashers And Speed Control At High-Speed Signalized Intersections, Zifeng Wu, Anuj Sharma, Fred L. Mannering, Shefang Wang
Safety Impacts Of Signal-Warning Flashers And Speed Control At High-Speed Signalized Intersections, Zifeng Wu, Anuj Sharma, Fred L. Mannering, Shefang Wang
Anuj Sharma
For many years, to reduce the crash frequency and severity at high-speed signalized intersections, warning flashers have been used to alert drivers of potential traffic-signal changes. Recently, more aggressive countermeasures at such intersections include a speed-limit reduction in addition to warning flashers. While such speed-control strategies have the potential to further improve the crash-mitigation effectiveness of warning flashers, a rigorous statistical analysis of crash data from such intersections has not been undertaken to date. This paper uses 10-year crash data from 28 intersections in Nebraska (all with intersection approaches having signal-warning flashers; some with no speed-limit reduction, and the others …
Finite Element Simulation Of Wind Turbine Aerodynamics: Validation Study Using Nrel Phase Vi Experiment, Ming-Chen Hsu, Ido Akkerman, Yuri Bazilevs
Finite Element Simulation Of Wind Turbine Aerodynamics: Validation Study Using Nrel Phase Vi Experiment, Ming-Chen Hsu, Ido Akkerman, Yuri Bazilevs
Ming-Chen Hsu
A validation study using the National Renewable Energy Laboratory (NREL) Phase VI wind turbine is presented. The aerodynamics simulations are performed using the finite element arbitrary Lagrangian–Eulerian–variational multiscale formulation augmented with weakly enforced essential boundary conditions. In all cases, the rotor is assumed to be rigid and its rotation is prescribed. The rotor-only simulations are performed for a wide range of wind conditions, and the computational results compare favorably with the experimental findings in all cases. The sliding-interface method is adopted for the simulation of the full wind turbine configuration. The full-wind-turbine simulations capture the blade–tower interaction effect, and the …
Blended Isogeometric Shells, D. J. Benson, S. Hartmann, Y. Bazilevs, Ming-Chen Hsu, T.J.R. Hughes
Blended Isogeometric Shells, D. J. Benson, S. Hartmann, Y. Bazilevs, Ming-Chen Hsu, T.J.R. Hughes
Ming-Chen Hsu
We propose a new isogeometric shell formulation that blends Kirchhoff–Love theory with Reissner–Mindlin theory. This enables us to reduce the size of equation systems by eliminating rotational degrees of freedom while simultaneously providing a general and effective treatment of kinematic constraints engendered by shell intersections, folds, boundary conditions, the merging of NURBS patches, etc. We illustrate the blended theory’s performance on a series of test problems.
Structural Health Monitoring System And Method Using Soft Capacitive Sensing Materials, Simon Laflamme, Matthias Kollosche, Guggi H. R. Kofod
Structural Health Monitoring System And Method Using Soft Capacitive Sensing Materials, Simon Laflamme, Matthias Kollosche, Guggi H. R. Kofod
Simon Laflamme
A structural health monitoring system is provided to diagnose and localize crack damage on structural elements. The system uses one or more capacitive sensor assemblies that employ a soft dielectric material. The system can be applied over a large area as a sensing skin, allowing the presence of cracks to be localized.
Joint Base Station Clustering And Beamformer Design For Partial Coordinated Transmission In Heterogeneous Networks, Mingyi Hong, Ruoyu Sun, Hadi Baligh, Zhi-Quan Luo
Joint Base Station Clustering And Beamformer Design For Partial Coordinated Transmission In Heterogeneous Networks, Mingyi Hong, Ruoyu Sun, Hadi Baligh, Zhi-Quan Luo
Mingyi Hong
We consider the interference management problem in a multicell MIMO heterogeneous network. Within each cell there is a large number of distributed micro/pico base stations (BSs) that can be potentially coordinated for joint transmission. To reduce coordination overhead, we consider user-centric BS clustering so that each user is served by only a small number of (potentially overlapping) BSs. Thus, given the channel state information, our objective is to jointly design the BS clustering and the linear beamformers for all BSs in the network. In this paper, we formulate this problem from a {sparse optimization} perspective, and propose an efficient algorithm …
Out-Of-Classroom Experiences: Bridging The Disconnect Between The Classroom, The Engineering Workforce, And Ethical Development, Brian A. Burt, Donald D. Carpenter, Matthew A. Holsapple, Cynthia J. Finelli, Rob M. Bielby, Janel A. Sutkus, Trevors S. Harding
Out-Of-Classroom Experiences: Bridging The Disconnect Between The Classroom, The Engineering Workforce, And Ethical Development, Brian A. Burt, Donald D. Carpenter, Matthew A. Holsapple, Cynthia J. Finelli, Rob M. Bielby, Janel A. Sutkus, Trevors S. Harding
Brian Burt A.
The extant research on engineering ethics instruction shows that students receive ethics instruction within the engineering curricula. Unfortunately, the methods used in engineering undergraduate classrooms are described as ‘‘abstract’’ and have mixed results related to impacting students’ ethical development. Thus, exploring how out-of-classroom experiences—as a curricular alternative—influences students’ ethical development is warranted. This is an exploratory investigation to determine how out-of-classroom experiences influence students’ ethical development. The authors define ethical development using three constructs: knowledge of ethics, ethical reasoning, and ethical behavior. We draw upon a conceptual model that suggests students’ ethical development is impacted by what takes place inside …
Derivative Estimation With Local Polynomial Fitting, Kris De Brabanter, Jos De Brabanter, Bart De Moor, Irene Gijbels
Derivative Estimation With Local Polynomial Fitting, Kris De Brabanter, Jos De Brabanter, Bart De Moor, Irene Gijbels
Kris De Brabanter
We present a fully automated framework to estimate derivatives nonparametrically without estimating the regression function. Derivative estimation plays an important role in the exploration of structures in curves (jump detection and discontinuities), comparison of regression curves, analysis of human growth data, etc. Hence, the study of estimating derivatives is equally important as regression estimation itself. Via empirical derivatives we approximate the qth order derivative and create a new data set which can be smoothed by any nonparametric regression estimator. We derive L1 and L2 rates and establish consistency of the estimator. The new data sets created by this technique are …
Biophotonic Logic Devices Based On Quantum Dots And Temporally-Staggered Forster Energy Transfer Relays, Jonathan C. Claussen, W. Russ Algar, Niko Hildebrandt, Kimihiro Susumu, Mario G. Ancona, Igor L. Medintz
Biophotonic Logic Devices Based On Quantum Dots And Temporally-Staggered Forster Energy Transfer Relays, Jonathan C. Claussen, W. Russ Algar, Niko Hildebrandt, Kimihiro Susumu, Mario G. Ancona, Igor L. Medintz
Jonathan C. Claussen
Integrating photonic inputs/outputs into unimolecular logic devices can provide significantly increased functional complexity and the ability to expand the repertoire of available operations. Here, we build upon a system previously utilized for biosensing to assemble and prototype several increasingly sophisticated biophotonic logic devices that function based upon multistep Förster resonance energy transfer (FRET) relays. The core system combines a central semiconductor quantum dot (QD) nanoplatform with a long-lifetime Tb complex FRET donor and a near-IR organic fluorophore acceptor; the latter acts as two unique inputs for the QD-based device. The Tb complex allows for a form of temporal memory by …
Mild Yet Phase-Selective Preparation Of Tio2 Nanoparticles From Ionic Liquids – A Critical Study, Tarek Alammar, Heshmat Noei, Yuemin Wang, Anja V. Mudring
Mild Yet Phase-Selective Preparation Of Tio2 Nanoparticles From Ionic Liquids – A Critical Study, Tarek Alammar, Heshmat Noei, Yuemin Wang, Anja V. Mudring
Anja V. Mudring
The phase selective synthesis of nanocrystalline TiO2, titania, in ionic liquids (ILs) is explored. The influence not only of the IL but also of the Ti-precursor, pH, and temperature is investigated. Sonochemical synthesis, microwave synthesis and conventional heating are compared. In the case of Ti(OiPr)4 (OiPr ¼ isopropyl) as the Ti-source the ILs [C4mim][Tf2N] (1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide), [C3mimOH][Tf2N] (1-(3-hydroxypropyl)-3-methylimidazolium bis(trifluoromethanesulfonyl)amide), [C4Py]- [Tf2N] (butylpyridinium bis(trifluoromethanesulfonyl)amide), [N1888][Tf2N] (methyltrioctylammonium bis- (trifluoromethanesulfonyl)amide), and [P66614][Tf2N] (tetradecyltrihexyl phosphonium bis(trifluoromethanesulfonyl) amide) led at ambient temperature to TiO2 in the form of anatase. The morphology of nano-anatase is controlled by the IL cation. Anatase nanospheres with a crystal size …
Tin Dioxide–Carbon Heterostructures Applied To Gas Sensing: Structure-Dependent Properties And General Sensing Mechanism, Catherine Marichy, Patricia A. Russo, Mariangela Latino, Jean-Philippe Tessonnier, Marc-Georg Willinger, Nicola Donato, Giovanni Neri, Nicola Pinna
Tin Dioxide–Carbon Heterostructures Applied To Gas Sensing: Structure-Dependent Properties And General Sensing Mechanism, Catherine Marichy, Patricia A. Russo, Mariangela Latino, Jean-Philippe Tessonnier, Marc-Georg Willinger, Nicola Donato, Giovanni Neri, Nicola Pinna
Jean-Philippe Tessonnier
Carbon materials such as carbon nanotubes (CNTs), graphene, and reduced graphene oxide (RGO) exhibit unique electrical properties, which are also influenced by the surrounding atmosphere. They are therefore promising sensing materials. Despite the existence of studies reporting the gas-sensing properties of metal oxide (MOx) coated nanostructured carbon, an incomplete understanding of their sensing mechanism remains. Here we report a systematic study on the preparation, characterization, and sensing properties of CNT and RGO composites with SnO2 coating. Atomic layer deposition (ALD) was applied to the conformal coating of the inner and outer walls of CNTs with thin films of SnO2 of …
Yttrium(Iii) Oxomolybdates(Vi) As Potential Host Materials For Luminescence Applications: An Investigation Of Eu3+-Doped Y2[Moo4]3 And Y2[Moo4]2[Mo2o7], Sonja Laufer, Sabine Strobel, Thomas Schleid, Joanna Cybinska, Anja V. Mudring, Ingo Hartenbach
Yttrium(Iii) Oxomolybdates(Vi) As Potential Host Materials For Luminescence Applications: An Investigation Of Eu3+-Doped Y2[Moo4]3 And Y2[Moo4]2[Mo2o7], Sonja Laufer, Sabine Strobel, Thomas Schleid, Joanna Cybinska, Anja V. Mudring, Ingo Hartenbach
Anja V. Mudring
Two ternary yttrium(III) oxomolybdates(VI) are investigated, both structurally and spectroscopically. The crystal structure of Y2[MoO4]3 was solved at room temperature in the orthorhombic space group Pba2 (a = 1030.21(3), b = 1032.41(3), c = 1057.25(3) pm, Z = 4). In the unit cell, three discrete ortho-oxomolybdate(VI) units [MoO4]2− and two Y3+ cations, both with CN = 7 featuring a monocapped trigonal-prismatic oxygen environment, can be distinguished. Y2[MoO4]2[Mo2O7] crystallizes monoclinically in the space group P21/c (a = 681.85(2), b = 959.13(3), c = 1052.99(3) pm, β = 105.586(2)°) with two formula units per unit cell. In this compound the anionic environment …
Refactoring The Silent Spectinabilin Gene Cluster Using A Plug-And-Play Scaffold, Zengyi Shao, Guodong Rao, Chun Li, Zhanar Abil, Yunzi Luo, Huimin Zhao
Refactoring The Silent Spectinabilin Gene Cluster Using A Plug-And-Play Scaffold, Zengyi Shao, Guodong Rao, Chun Li, Zhanar Abil, Yunzi Luo, Huimin Zhao
Zengyi Shao
Natural products (secondary metabolites) are a rich source of compounds with important biological activities. Eliciting pathway expression is always challenging but extremely important in natural product discovery because an individual pathway is tightly controlled through a unique regulation mechanism and hence often remains silent under the routine culturing conditions. To overcome the drawbacks of the traditional approaches that lack general applicability, we developed a simple synthetic biology approach that decouples pathway expression from complex native regulations. Briefly, the entire silent biosynthetic pathway is refactored using a plug-and-play scaffold and a set of heterologous promoters that are functional in a heterologous …
Activation And Characterization Of A Cryptic Polycyclic Tetramate Macrolactam Biosynthetic Gene Cluster, Yunzi Luo, Hua Huang, Jing Liang, Meng Wang, Lu Lu, Zengyi Shao, Ryan E. Cobb, Huimin Zhao
Activation And Characterization Of A Cryptic Polycyclic Tetramate Macrolactam Biosynthetic Gene Cluster, Yunzi Luo, Hua Huang, Jing Liang, Meng Wang, Lu Lu, Zengyi Shao, Ryan E. Cobb, Huimin Zhao
Zengyi Shao
Polycyclic tetramate macrolactams (PTMs) are a widely distributed class of natural products with important biological activities. However, many of these PTMs have not been characterized. Here we apply a plug-and-play synthetic biology strategy to activate a cryptic PTM biosynthetic gene cluster SGR810-815 from Streptomyces griseus and discover three new PTMs. This gene cluster is highly conserved in phylogenetically diverse bacterial strains and contains an unusual hybrid polyketide synthase-nonribosomal peptide synthetase, which resembles iterative polyketide synthases known in fungi. To further characterize this gene cluster, we use the same synthetic biology approach to create a series of gene deletion constructs and …
Improving Coalition Planning By Making Plans Alive, Jitu Patel, Michael C. Dorneich, David Mott, Ali Bahrami, Cheryl Giammanco
Improving Coalition Planning By Making Plans Alive, Jitu Patel, Michael C. Dorneich, David Mott, Ali Bahrami, Cheryl Giammanco
Michael C. Dorneich
The Collaborative Planning Model (CPM) supports human planners in managing planning information and facilitating automated reasoning. It aims to make plans 'alive' by digitizing planning concepts to facilitate their dynamic use, modification, dissemination, and reuse.
Empirical Data And Regression Analysis For Estimation Of Infrastructure Resilience With Application To Electric Power Outages, Cameron A. Mackenzie, Kash Barker
Empirical Data And Regression Analysis For Estimation Of Infrastructure Resilience With Application To Electric Power Outages, Cameron A. Mackenzie, Kash Barker
Cameron A. MacKenzie
Recent natural disasters have highlighted the need for increased planning for disruptive events. Forecasting damage and time that a system will be inoperable is important for disruption planning. The resilience of critical infrastructure systems, or their ability to recover quickly from a disruption, can mitigate adverse consequences of the disruption. This paper quantifies the resilience of a critical infrastructure sector through the dynamic inoperability input-output model (DIIM). The DIIM, which describes how inoperability propagates through a set of interdependent industry and infrastructure sectors following a disruptive event, includes a resilience parameter that has not yet been adequately assessed. This paper …
Emerging Technologies For Non-Invasive Quantification Of Physiological Oxygen Transport In Plants, P. Chaturvedi, M. Taguchi, S. L. Burrs, B. A. Hauser, W.W. A.W. Salim, Jonathan C. Claussen, E. S. Mclamore
Emerging Technologies For Non-Invasive Quantification Of Physiological Oxygen Transport In Plants, P. Chaturvedi, M. Taguchi, S. L. Burrs, B. A. Hauser, W.W. A.W. Salim, Jonathan C. Claussen, E. S. Mclamore
Jonathan C. Claussen
Oxygen plays a critical role in plant metabolism, stress response/signaling, and adaptation to environmental changes (Lambers and Colmer, Plant Soil 274:7-15, 2005; Pitzschke et al., Antioxid Redox Signal 8:1757-1764, 2006; Van Breusegem et al., Plant Sci 161:405-414, 2001). Reactive oxygen species (ROS), by-products of various metabolic pathways in which oxygen is a key molecule, are produced during adaptation responses to environmental stress. While much is known about plant adaptation to stress (e.g., detoxifying enzymes, antioxidant production), the link between ROS metabolism, O2 transport, and stress response mechanisms is unknown. Thus, non-invasive technologies for measuring O2 are critical for understanding the …
Interface-Assisted Ionothermal Synthesis, Phase Tuning, Surface Modification And Bioapplication Of Ln3+-Doped Nagdf4 Nanocrystals, Qiang Ju, Paul S. Campbell, Anja V. Mudring
Interface-Assisted Ionothermal Synthesis, Phase Tuning, Surface Modification And Bioapplication Of Ln3+-Doped Nagdf4 Nanocrystals, Qiang Ju, Paul S. Campbell, Anja V. Mudring
Anja V. Mudring
Phase-selective synthesis of trivalent lanthanide-doped NaGdF4 nanocrystals, capped by ionic liquid cations bearing long alkyl chains, succeeded via a one-step interface-assisted ionothermal route. Owing to the existence of an interface formed between hydrophobic ionic liquids and ethylene glycol, selectively either pure cubic or hexagonal phase NaGdF4 could be obtained by changing the amount of the added surfactant, polyethyleneimine. By doping various trivalent lanthanide cations, multicolor emissions under excitation by a single wavelength could be achieved. The nanocrystals can be surface derivatized by an amphiphilic polymer and endowed with functional groups that allow the particles to not only be dispersed in …
Phase And Morphology Selective Interface-Assisted Synthesis Of Highly Luminescent Ln3+-Doped Nagdf4 Nanorods, Anja V. Mudring, Qiang Ju
Phase And Morphology Selective Interface-Assisted Synthesis Of Highly Luminescent Ln3+-Doped Nagdf4 Nanorods, Anja V. Mudring, Qiang Ju
Anja V. Mudring
Making use of the multifunctional properties of ionic liquids by employing them as a fluoride resource and hydrophilic phase, we have grown small, monodisperse, highly luminescent Ln3+-doped NaGdF4 nanorods at the interface between octadecene and the reactive ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate. The obtained nanocrystals could further be endowed with functional groups and rendered water dispersible, which allows them to be used for biodetection.
White-Light-Emitting Single Phosphors Via Triply Doped Laf3 Nanoparticles, Chantal Lorbeer, Anja V. Mudring
White-Light-Emitting Single Phosphors Via Triply Doped Laf3 Nanoparticles, Chantal Lorbeer, Anja V. Mudring
Anja V. Mudring
The production of high-quality phosphors for white-emitting applications is an important goal for the settlement of light-emitting diodes (LEDs) in the market and households. Single phosphors directly yielding white emission are advantageous in comparison to a mixture of individual red, green, and blue phosphors as these are hampered by reabsorption of the blue light. Here, a combined approach to uniform, nanoscale particles as single-white-emitting phosphor is realized via an ionic-liquid-based synthesis. LaF3 particles codoped with various amounts of Tm3+, Tb3+, and Eu3+ were synthesized, and their structural, morphological, and optical properties were studied. Small particles with a mean size of …
On The Mesophase Formation Of 1,3-Dialkylimidazolium Ionic Liquids, Mei Yang, Bert Mallick, Anja V. Mudring
On The Mesophase Formation Of 1,3-Dialkylimidazolium Ionic Liquids, Mei Yang, Bert Mallick, Anja V. Mudring
Anja V. Mudring
A series of seven different 1,3-dialkylimidazolium-based ion-pair salts with the same molecular weight and size but different symmetries was synthesized. For all salts, bromide was chosen as the counterion, giving the series ([CnIMCm][Br]), where IM = imidazolium and Cn and Cm are varying N-alkyl substituents with n + m = 13. Thus, the effect of symmetry on the physicochemical properties, such as thermal transitions, densities and viscosities and particularly mesophase formation, is investigated herein. All salts are fully characterized by NMR spectroscopy and mass spectrometry, and their physicochemical properties such as thermal transitions, densities, and viscosities are reported. Single crystal …
A Unified Convergence Analysis Of Block Successive Minimization Methods For Nonsmooth Optimization, Meisam Razaviyayn, Mingyi Hong, Zhi-Quan Luo
A Unified Convergence Analysis Of Block Successive Minimization Methods For Nonsmooth Optimization, Meisam Razaviyayn, Mingyi Hong, Zhi-Quan Luo
Mingyi Hong
The block coordinate descent (BCD) method is widely used for minimizing a continuous function f of several block variables. At each iteration of this method, a single block of variables is optimized, while the remaining variables are held fixed. To ensure the convergence of the BCD method, the subproblem of each block variable needs to be solved to its unique global optimal. Unfortunately, this requirement is often too restrictive for many practical scenarios. In this paper, we study an alternative inexact BCD approach which updates the variable blocks by successively minimizing a sequence of approximations of f which are either …
Linear Transceiver Design For A Mimo Interfering Broadcast Channel Achieving Max–Min Fairness, Meisam Razaviyayn, Mingyi Hong, Zhi-Quan Luo
Linear Transceiver Design For A Mimo Interfering Broadcast Channel Achieving Max–Min Fairness, Meisam Razaviyayn, Mingyi Hong, Zhi-Quan Luo
Mingyi Hong
This problem can be formulated as maximizing the minimum rate among all the users in an interfering broadcast channel (IBC). In this paper we show that when the number of antennas is at least two at each of the transmitters and the receivers, the min rate maximization problem is NP-hard in the number of users. Moreover, we develop a low-complexity algorithm for this problem by iteratively solving a sequence of convex subproblems. We theoretically establish the global convergence of the proposed algorithm to the set of stationary points, which may be suboptimal due to the non-convexity of the original minimum …