87 research outputs found
Anisotropic He-ion irradiation damages in nanocolumnarWthin films
No full textThe effects of He-ion irradiation on the microstructures and the mechanical, thermal properties of sputter-deposited nanocolumnar tungsten thin films have been studied. 200 keV He+ ion irradiation with a fluence of 2x1017 ions/cm2 was performed in the growth direction of the W thin films. Small scale mechanical testing methods, such as nanoindentation and square membrane deflection experiments, were carried out, and the thermal conductivity measurement was performed based on the electrical resistivity measurement and the Wiedemann–Franz law for the unirradiated and irradiated W thin films. It was revealed that the properties in the out-of-plane direction are not changed much, but a significant degradation occurs in the in-plane direction after the He-ion irradiation. The microstructure of the film and the distribution of He-ion induced damages are responsible for the anisotropic property changes by He-ion irradiation.
31.2 A 0.9V 28MHz Dual-RC Frequency Reference with 5pJ/Cycle and ±200 ppm Inaccuracy from -40°C to 85°C
No full textWireless sensor nodes in battery-powered internet-of-things (loT) applications require a stable on-chip frequency reference with low energy (<10 pJ / cycle) and high frequency stability (below ±300ppm). CMOS RC frequency references are promising due to their low-cost integration and high energy efficiency [1] –[5]. Conventional RC references, however, achieve only moderate accuracy (a few %) due to the large temperature coefficient (TC) of on-chip resistors [3]. First-order TC compensation can be achieved by combining resistors with complementary TCs [1], [2]. Although this is energy efficient (<6 pJ / cycle), it only partially compensates for the resistors’ high-order TCs, limiting the resulting accuracy to about ±500 ppm. Better accuracy (±100 ppm [4]) can be achieved by using the output of a digital temperature sensor (TS) to perform a polynomial correction of the phase-shift (μp,T) of an RC filter (Fig. 31.2.1). Alternatively, the phase-shifts (μp. and μN) of two RC filters with complementary TCs can be linearized (Tp. and T N ) and combined in the digital domain. Such dual-RC frequency references can also achieve good accuracy (±200 ppm [5]). However, both architectures employ an analog phase-domain ΔΣ modulator (Φ−ΔΣM) for each RC filter, which consumes significant energy (25pJ/cycle [4] and 107pJ/ cycle [5]) and area (0.3mm2[4]. and 1.65mm2[5]).Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.MicroelectronicsElectronic Instrumentatio
[Photograph 2012.201.B0412B.0122]
No full textPhotograph used for a story in the Daily Oklahoman newspaper. Caption: "Injun catcher Joe Bell and Gov. Johnston Murray go over their signals before the governor makes the first pitch at Texas League Park Saturday night.
[Photograph 2012.201.B1275.0753]
No full textPhotograph used for a story in the Daily Oklahoman newspaper. Caption: "injun manager tom Tatum signs autographs for some of the Boy swcout night crowd at Texas League park Friday night.
Ataxin-2 Dysregulation Triggers a Compensatory Fragile X Mental Retardation Protein Decrease in Drosophila C4da Neurons
No full textDendrites require precise and timely delivery of protein substrates to distal areas to ensure the correct morphology and function of neurons. Many of these protein substrates are supplied in the form of ribonucleoprotein (RNP) complex consisting of RNA-binding proteins (RBPs) and mRNAs, which are subsequently translated in distal dendritic areas. It remains elusive, however, whether key RBPs supply mRNA according to local demands individually or in a coordinated manner. In this study, we investigated how Drosophila sensory neurons respond to the dysregulation of a disease-associated RBP, Ataxin-2 (ATX2), which leads to dendritic defects. We found that ATX2 plays a crucial role in spacing dendritic branches for the optimal dendritic receptive fields in Drosophila class IV dendritic arborization (C4da) neurons, where both expression level and subcellular location of ATX2 contribute significantly to this effect. We showed that translational upregulation through the expression of eukaryotic translation initiation factor 4E (eIF4E) further enhanced the ATX2-induced dendritic phenotypes. Additionally, we found that the expression level of another disease-associated RBP, fragile X mental retardation protein (FMRP), decreased in both cell bodies and dendrites when neurons were faced with aberrant upregulation of ATX2. Finally, we revealed that the PAM2 motif of ATX2, which mediates its interaction with poly(A)-binding protein (PABP), is potentially necessary for the decrease of FMRP in certain neuronal stress conditions. Collectively, our data suggest that dysregulation of RBPs triggers a compensatory regulation of other functionally-overlapping RBPs to minimize RBP dysregulation-associated aberrations that hinder neuronal homeostasis in dendrites. © The Korean Society for Molecular and Cellular Biology. All rights reserved.1
An 8MHz 31.25kS/s Impedance-Monitoring IC Based on IF-Sampling Architecture with a Band-Pass Delta-Sigma ADC
No full textWe present an impedance-monitoring IC achieving a wide frequency range (FR) and fast output data rate (ODR). The proposed IC support a wide FR with improved spectral density by down-converting the signal to the intermediate frequency (fIF) in front of the instrumentation amplifier (IA) using the LO signal generated by a single-side-band (SSB) mixer. The proposed IF-sampling architecture does not require narrow-bandwidth (BW) low-pass filter (LPF), resulting in a fast ODR. A time-interleaved (TI) DFT is also employed to further improve the ODR. A band-pass delta-sigma ADC (BP-ΔΣ-ADC) with the auto-calibration and BP truncation is adopted to achieve the best noise performance at fIF. The fabricated IC achieves 0.35ΩRMS resolution in the FR from 4kHz to 8MHz with 122.1Hz BW while providing the ODR up to 31.25kS/s
A 0.9-V 28-MHz Highly Digital CMOS Dual-RC Frequency Reference With ±200 ppm Inaccuracy From -40 °C to 85 °C
No full textThis article presents an energy-efficient dual- RC frequency reference intended for wireless sensor nodes. It consists of a digital frequency-locked loop (FLL) in which the frequency of a digitally controlled oscillator (DCO) is locked to a temperature-independent phase shift derived from two different RC poly-phase filters (PPFs). Phase shifts with complementary temperature coefficients (TCs) are generated by using PPFs made from different resistor types (p-poly and silicided p-poly). The phase shift of each filter is determined by a zero-crossing (ZC) detector and then digitized by a digital phase-domain ΔΣ modulator ( Φ - ΔΣM ). The results are then combined in the digital domain via fixed polynomials to produce a temperature-independent phase shift. This highly digital architecture enables the use of a sub-1-V supply voltage and enhances energy and area efficiency. The 28-MHz frequency reference occupies 0.06 mm2 in a 65-nm CMOS process. It achieves a period jitter of 7 ps ( 1σ ) and draws 142 μW from a 0.9-V supply, which corresponds to an energy consumption of 5 pJ/cycle. Furthermore, it achieves ±200 ppm inaccuracy from −40∘C to 85 ∘C after a two-point trim.</p
Facile membrane upscaling via in-situ synthesis of PVA hydrogel for harsh solvent separation: From transport study to industrial application
No full textIn this study, a facile upscaled membrane module was developed using an in-situ hydrogel synthesis technique for the selective removal of water from harsh organic solvent mixtures by pervaporation. Polyvinyl alcohol (PVA) was chosen as the hydrophilic membrane material due to its ease of chemical modification and high processible film-forming stability. A porous alpha-alumina hollow fiber was used as a support, and an in-situ hydrogel reaction with glutaraldehyde was employed to form a uniform selective layer without the penetration issues commonly faced during conventional membrane fabrication. It was found that the synthesized hydrogel (s-HPGA) exhibited improved water permeation performance resulting from the mechanically expanded free volume within the membrane matrix and uncommon diffusive properties verified by diffusivity modeling. The effectiveness of the fabricated s-HPGA membrane modules was demonstrated through a cyclic pervaporation test involving an epoxy manufacturing by-product mixture. The results showed that the module achieved stable performance and efficient water separation over 200 h of operation with a recovery rate of over 98%. In addition, the field application test demonstrated that the s-HPGA membrane module is well-suited for industrial applications requiring solvent enrichment and efficient dehydration.
Fluorinated Epoxy Hybrid Material for Transparent Low-k Passivation Layer on Oxide Thin Film Transistors
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