391 research outputs found
Supplementary data - Supplemental material for Study in Pesticide Activities of <i>Polygonum cuspidatum</i> Extracts and its Active Ingredient Resveratrol
No full textSupplemental material, Supplementary data, for Study in Pesticide Activities of Polygonum cuspidatum Extracts and its Active Ingredient Resveratrol by Wenqiang Yang, Fenglu Li, Xiaoyi Xing, Zhen Wang, and Xiuling Yu in Natural Product Communications</p
Supplemental_Material – Supplemental material for Effects of a 3D-printed orthosis compared to a low-temperature thermoplastic plate orthosis on wrist flexor spasticity in chronic hemiparetic stroke patients: a randomized controlled trial
No full textSupplemental material, Supplemental_Material for Effects of a 3D-printed orthosis compared to a low-temperature thermoplastic plate orthosis on wrist flexor spasticity in chronic hemiparetic stroke patients: a randomized controlled trial by Yanan Zheng, Gongliang Liu, Long Yu, Yanmin Wang, Yuan Fang, Yikang Shen, Xiuling Huang, Lei Qiao, Jianzhong Yang, Ying Zhang and Zikai Hua in Clinical Rehabilitation</p
Graphene nano-ribbon and transition metal dichalcogenide field-effect transistor modeling and circuit simulation
No full textThis dissertation presents a modeling and simulation study of graphene nano-ribbon and transition metal dichalcogenide field-effect transistors. Through compact modeling, SPICE implementation of the transistors is realized, and circuit-level simulation is enabled. Extensive simulation studies are performed to evaluate the performance of these two emerging devices.Submission published under a 24 month embargo labeled 'U of I only', the embargo will last until 2017-08-01The student, Ying-Yu Chen, accepted the attached license on 2015-07-17 at 09:56.The student, Ying-Yu Chen, submitted this Dissertation for approval on 2015-07-17 at 10:01.This Dissertation was approved for publication on 2015-07-17 at 12:03.DSpace SAF Submission Ingestion Package generated from Vireo submission #8521 on 2015-09-29 at 15:00:41Made available in DSpace on 2015-09-29T20:50:17Z (GMT). No. of bitstreams: 2
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Previous issue date: 2015-07-17Embargo set by: Seth Robbins for item 89492
Lift date: 2017-09-29T20:50:34Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemU of I Only Restriction Lifted for Item 89492 on 2017-09-30T09:15:24Z
Printed microscale mono-crystalline silicon on flexible substrates for photovoltaic, strain sensors, and neural interface applications
No full textIn recent years, research in flexible electronic systems has increased due to its potential to create and manipulate new classes of applications (e.g., foldable and flexible display, flexible photovoltaic, epidermal electronics, and other systems) that can be integrated outside of conventional wafer-based electronics. With suitable choice of materials and design strategies, inorganic semiconductors (e.g., Si and GaAs) can be used on unconventional substrates for mechanical flexibility and high electrical performance. This dissertation presents the fabrication of mono-crystalline Si electronics by using top-down approaches. We describe five related topics of ultra-thin Si electronics which involve forming structures and assembling them by structured or non-structured elastomeric stamps or bulk wafer etching techniques. Furthermore, this dissertation demonstrates a strategy in which modules consist of large-scale arrays of interconnected high-performance ultra-thin Si electronics that are mechanically flexible, stretchable, and semitransparent, along with in-depth studies of their electrical and mechanical properties and applications.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2017-12-01The student, Ki Jun Yu, accepted the attached license on 2015-11-16 at 18:34.The student, Ki Jun Yu, submitted this Dissertation for approval on 2015-11-16 at 18:53.This Dissertation was approved for publication on 2015-11-18 at 17:03.DSpace SAF Submission Ingestion Package generated from Vireo submission #8793 on 2016-03-02 at 14:13:11Made available in DSpace on 2016-03-02T21:06:33Z (GMT). No. of bitstreams: 2
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Previous issue date: 2015-11-18Embargo set by: Seth Robbins for item 91406
Lift date: 2018-03-02T21:07:27Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemLimited Restriction Lifted for Item 91406 on 2018-03-03T10:15:35Z
Semiconductor quantum dots for mid-IR light emission
No full textMid-infrared wavelength range (3 μm to 30 μm) is important in many applications such as environmental monitoring, industrial process control, bio- medical imaging, security and defense. The mid-IR is the spectral home of the distinct vibrational and rotational absorption resonance signatures of a wide range of molecular species, giving mid-IR sensing systems the potential to enable the monitoring and identification of molecules for gas sensing or chemical and biological imaging applications. To enable many of the above applications, compact, high efficiency, and low-cost mid-IR emitters and detectors are required. The goal of this project is to develop highly efficient and low-cost mid-IR emitters.
The first part of this thesis gives an introduction to why mid-IR light is important and the state-of-the-art mid-IR sources. We discuss the working theory, structure, advantages and disadvantages of quantum cascade laser (QCL), interband cascade laser and type-I quantum well lasers, which together cover the wavelength range from 2 μm to 11 μm. Then, in the last part of chapter 1, we provide an introduction to quantum dots and a discussion as to why we might want to use quantum dots to improve the performance of QCLs. Here we will discuss primarily two types of quantum dots: those that are generally referred to as patterned (either etched top down, or site-selectively grown), and self-assembled QDs (SAQD). In this project, we studied studied mechanisms for control of energy states in both top-down nanolithographically defined QD and bottom-up InAs submono-layer QD grown by MBE.
We demonstrate strong carrier confinement in, and electroluminescence (EL) from, quantum nanostructures fabricated from epitaxially grown quan- tum wells (QWs) using a top-down nanosphere lithography (NSL), dry-etch, mass-transport, and overgrowth fabrication process. Optically active nano- pillars with diameters as small as 90 nm are fabricated, and narrow linewidth(18 meV) electroluminescence from a fabricated diode structure is observed, with an emission blue-shift of over 37 meV from the original quantum well sample luminescence. The results presented offer the potential for low-cost, large-area patterning of quantum nanostructures for optoelectronic applications. However, the NSL defined QD density is limited by the size of the NS used. For 200 nm diameter size NS, the QD density can only reach to 2.5 ∗ 109/cm2 which is likely not nearly high enough for most optoelectronic applications. For this reason, we started to study InAs submonolayer quantum dots (in the next chapter), aiming to use InAs SML QD in the QCL active region.
The thesis then goes on to discuss work demonstrating control of energy states in epitaxially-grown quantum dot structures formed by stacked sub- monolayer InAs depositions via engineering of the internal bandstructure of the dots. Transmission electron microscopy of the stacked submonolayer re- gions shows compositional inhomogeneity, indicative of the presence of quantum dots. The quantum dot ground state is manipulated not only by the number of deposited InAs layers, but also by control of the thickness and material composition of the spacing layers between submonolayer InAs de- positions. In this manner, we demonstrate the ability to shift the quantum dot ground state energy at 77K from 1.38 eV to 1.88 eV. The results pre- sented offer a potential avenue towards enhanced control of dot energies for a variety of optoelectronic applications. The SML QD structures were then integrated into QCL-like structures, with our SML deposition in the active region.
We also demonstrate infrared light emission from thin epitaxially grown In(Ga)Sb layers in InAs(Sb) matrices across a wide range (3-8 μm) of the mid- infrared spectral range. Our structures are characterized by x-ray diffraction, photo-electron spectroscopy, atomic force microscopy and transmission electron microscopy. Emission is characterized by temperature- and power- dependent infrared step-scan photoluminescence spectroscopy. The epitaxial In(Ga)Sb layers are observed to form either quantum wells, quantum dots, or disordered quantum wells, depending on the insertion layer and substrate material composition. The observed optical properties of the monolayer scale insertions are correlated to their structural properties, as determined by transmission electron and atomic force microscopy.
In this work, we employ time resolved PL to study the carrier recombination mechanism in a thin type II material system. With the experimental system we set up and the analysis process developed, we are able to resolve the Shockley-Read-Hall and radiative rates from our materials. This provides a powerful way to study the emitter quality. According to our TRPL study as well as the optical study, we find that the sample with obvious nano- structure formation has the best optical performance and material quality, which makes the QD structure the best candidate for mid-IR emitter and laser applications.
Finally, the thesis ends with a study of the growth of InGaSb QDs using MBE by systematically changing growth parameters such as substrate temperature, Ga/In ratio and layer thickness. A high density and high uniformity QD sample is grown and studied at the end of chapter 6. This sample shows a better temperature performance and a better material quality than any other samples without QD formation. From this work we are able to draw the conclusion that the type-II QD structure has the best potential in the future to be made into a low-cost, simple structure and high-performance room-temperature mid-IR emitters.Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2017-02-28 without embargo termsThe student, Lan Yu, accepted the attached license on 2016-11-29 at 14:15.The student, Lan Yu, submitted this Dissertation for approval on 2016-11-29 at 14:21.This Dissertation was approved for publication on 2016-11-29 at 15:36.DSpace SAF Submission Ingestion Package generated from Vireo submission #10353 on 2017-02-28 at 14:54:33Made available in DSpace on 2017-03-01T15:49:16Z (GMT). No. of bitstreams: 3
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Previous issue date: 2016-11-2
Next‐generation photochromic smart window: Wood‐derived cellulose flexible composites integrated thermal insulation, UV ‐shielding, and anti‐counterfeiting
No full textAbstract Addressing the dual challenges of global energy sustainability and dynamic optical management, we present an innovative flexible photochromic transparent fluorescent wood composite film (PT‐FWF) with molecular‐scale engineered design, fabricated through in situ Eu 3+ coordination on TEMPO‐oxidized cellulose scaffolds. This hierarchically structured material combines fluorescent wood film with hot‐pressing, impregnation, and coating (PMMA/WO 3 ) to achieve multimodal optical control. PT‐FWF demonstrates exceptional multifunctionality: 88% optical transparency, 107.5° ± 1.0° hydrophobicity surface, and thermal insulation (Δ T ≈ 5.5°C). A unique dual‐mode photoresponsive mechanism enables through synergistic photochromic‐fluorescent effects: instantaneous fluorescence under UV light and coloring/bleaching with or without light‐assisted (UV or simulated sunlight). The smart window model exhibits over 90% UV‐blocking efficiency, and the transmittance of the smart window can be reversibly switched between 88% and 5% under prolonged light conditions, showing a high modulation of visible light (∆ T lum = 83%) at 1030 nm, enabling simultaneous daylight optimization and energy conservation. This molecular‐scale engineered wood composite defines a transformative platform for adaptive optical materials, merging energy‐efficient architectural solutions with information encryption through sunlight‐regulated smart windows that simultaneously enable environmental protection and anti‐counterfeiting. imageNatural Science Foundation of Jiangsu Province https://doi.org/10.13039/50110000460
Chip scale monolithic integration of inductive and capacitive components by self-rolled-up membrane nanotechnology
No full textThis work reports a three-dimensional (3D) microwave L-C filter network enabled by a CMOS-compatible two-dimensional (2D) fabrication approach, which combines inductive (L) and capacitive (C) self-rolled-up membrane (S-RuM) components monolithically into a single L-C network structure, thereby greatly reducing the on-chip area footprint. The individual L-C elements are fabricated in-plane using standard semiconductor processing techniques, and subsequently triggered by the built-in stress to self-assemble and roll into cylindrical air-core architectures. By designing the planar structure geometry and constituent layer properties to achieve a specific number of turns with a desired inner diameter when the device is rolled up, the electrical characteristics can be engineered. The network layouts of the L and C components are also reconfigurable by selecting appropriate input, output, and ground contact routing topographies. The devices demonstrated here operate over the range of ~1-10 GHz. Their area and volume footprints are 0.095 mm2 and 0.01 mm3, respectively, which are ~10× smaller than most of the comparable conventional filter designs. These S-RuM-enabled 3D microtubular L-C filter networks represent a significant advancement for miniaturization and integration of RF devices for applications in mobile connectivity.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2022-12-01The student, Zhendong Yang, accepted the attached license on 2020-11-25 at 10:23.The student, Zhendong Yang, submitted this Thesis for approval on 2020-11-25 at 10:32.This Thesis was approved for publication on 2020-12-01 at 17:24.DSpace SAF Submission Ingestion Package generated from Vireo submission #15960 on 2021-03-04 at 16:32:27Made available in DSpace on 2021-03-05T21:45:37Z (GMT). No. of bitstreams: 5
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Previous issue date: 2020-12-01Embargo set by: Seth Robbins for item 117307
Lift date: 2023-03-05T21:45:47Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 117307
Lift date: 2023-03-05T21:47:41Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemAuthor requested closed access (OA after 2yrs) in Vireo ETD systemLimite
On-chip self-rolled-up nanomembrane tube inductor for RFIC performance enhancement
No full textMiniaturization of the commonly used on-chip lumped spiral inductor is highly desirable to reduce the fabrication cost and enhance the performance and functionality of radio frequency integrated circuits (RFICs). Numerous improvement methods have been demonstrated but all fail to fundamentally solve the intrinsic drawbacks of planar spiral structure, especially the most critical issue – substrate effects. A new design concept based on self-rolled-up nanomembrane nanotechnology that “processes like 2D and functions like 3D” is proposed and demonstrated. This thesis shows a global solution to obtain a lumped inductor with extremely small on-chip footprint and immunity to substrate effects. Experimental realization of self-rolled-up inductors shows a footprint two orders of magnitude smaller than that of the planar spiral inductors, with excellent quality factor (Q) and much higher operating frequency than the 2D counterparts in both capabilities.Item withdrawn by Laura Spradlin ([email protected]) on 2014-07-08T13:02:07Z
Item was in collections:
University of Illinois Theses & Dissertations (ID: 1)
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license.txt: 4059 bytes, checksum: 3cdecbe530105bb16d1ee26d34ddce68 (MD5)Embargo set by: Seth Robbins for item 50467
Lift date: 2016-09-16T17:13:01Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemLimited Restriction Lifted for Item 50467 on 2016-09-22T20:59:11Z
The habitat and population size data, sampling time, sampling size and sample size of each locality used for (a) mtDNA and (b) microsatellite analysis.
No full text<p>*Three samples of AKS (21, 22 and 23) obtained by Xiuling Wang in August 2005 had six toes on the hind limbs.</p
Metal-assisted chemical etching of β-gallium oxide
No full textβ-Ga2O3, with an ultra-wide bandgap (UWB) of ~ 4.6 – 4.9 eV and bulk substrate availability, has drawn enormous interest in the power electronics community. Fabricating high-aspect-ratio β-Ga2O3 3D nanostructures without surface damage is essential for next-generation power electronics. Nonetheless, dry etch typically damages the surface due to high-energy ions, while most wet etching techniques can only produce very limited aspect ratios. In this thesis, β-Ga2O3 fin arrays by inverse metal-assisted chemical etching (MacEtch), under UV light irradiation, with a high aspect ratio and excellent surface quality, are demonstrated. The strongly crystal-orientation-dependent etching behaviors are found and three kinds of vertical structures are formed after the MacEtch process. The Schottky barrier heights (SBHs) between platinum (Pt) and different MacEtch-formed β-Ga2O3 surfaces and sidewalls are found to decrease as the aspect ratio of the β-Ga2O3 structure increases. This behavior is attributed to the varying oxygen composition on the surface after MacEtch, as shown by the XPS and TEM examination. Very little hysteresis has been observed in the capacitance-voltage characteristics of the 3D Pt/ Al2O3/ β-Ga2O3 MOS capacitor structures, and the lowest interface trap density extracted from etched interfaces is only 2.73×1011cm-2-eV-1, which is comparable to that of other published values of unetched β-Ga2O3 surfaces. This confirms that MacEtch is an effective etching method for producing high quality β-Ga2O3 3D structures.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2021-12-01The student, Hsien-Chih Huang, accepted the attached license on 2019-12-06 at 16:24.The student, Hsien-Chih Huang, submitted this Thesis for approval on 2019-12-06 at 16:30.This Thesis was approved for publication on 2019-12-10 at 13:59.DSpace SAF Submission Ingestion Package generated from Vireo submission #14747 on 2020-02-28 at 17:23:52Made available in DSpace on 2020-03-02T22:15:15Z (GMT). No. of bitstreams: 2
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Previous issue date: 2019-12-10Embargo set by: Seth Robbins for item 113924
Lift date: 2022-03-02T22:15:21Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 113924
Lift date: 2022-03-02T22:18:25Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemU of I Only Restriction Lifted for Item 113924 on 2022-03-03T10:15:27Z
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