2,081 research outputs found

    Innovative Techniques for 60-GHz On-Chip Antennas on CMOS Substrate

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    The 60-GHz band has a 7-GHz of bandwidth enabling high data rate wireless communication. Also, it has a short wavelength allowing for passive devices integration into a chip, that is, fully integrated system-on-chip (SOC) is possible. This chapter features the design, implementation, and measurements of 60-GHz on-chip antennas (OCAs) on complementary-metal-oxide-semiconductor (CMOS) technology. OCAs are the primary barrier for the SOC solution due to their limited performance. This degraded performance comes from the low resistivity and the high permittivity of the CMOS substrate. We present here two innovative techniques to improve the CMOS OCAs’ performance. The first method utilizes artificial magnetic conductors to shield the OCA electromagnetically from the CMOS substrate. The second methodology employs the PN-junction properties to create a high resistivity layer. Both approaches target the mitigation of the losses of the CMOS substrate; hence, the radiation performance characteristics of the OCAs are enhanced

    Spin ordering and electronic texture in the bilayer iridate Sr3_3Ir2_2O7_7

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    Through a neutron scattering, charge transport, and magnetization study, the correlated ground state in the bilayer iridium oxide Sr3_3Ir2_2O7_7 is explored. Our combined results resolve scattering consistent with a high temperature magnetic phase that persists above 600 K, reorients at the previously defined TAF=280T_{AF}=280 K, and coexists with an electronic ground state whose phase behavior suggests the formation of a fluctuating charge or orbital phase that freezes below T70T^{*}\approx70 K. Our study provides a window into the emergence of multiple electronic order parameters near the boundary of the metal to insulator phase transition of the 5d Jeff=1/2J_{eff}=1/2 Mott phase.Comment: Revised text and figures. 4 pages, 4 figure

    Effect of Winter Canola Cultivar on Seed Yield, Oil, and Protein Content

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    Canola (Brassica napus L.) is an oilseed crop that can produce healthy cooking oil and animal feed byproducts. Although it is a relatively new crop, approved for human consumption less than 40 yr ago, advances in breeding have allowed for its production as a winter crop in the southeastern United States. There is little published research, however, related to its performance and quality in this region. Therefore, a study was conducted during the 2014–2015 (Year 1) and 2015–2016 (Year 2) seasons in Tennessee. Twenty-three varieties were planted in a randomized complete block design with four replications across both years to determine seed yield, seed oil, and seed protein content. Differences in fertilizer application rates, planting, and harvest management and differences in weather conditions probably led to significant interactions between years. Cultivar yields ranged from 1269 to 2647 and 1494 to 4199 kg ha−1, seed oil content ranged from 44 to 48% and from 43 to 46%, and seed protein content ranged from 20 to 24% and from 19 to 23% for Years 1 and 2, respectively. In each year, open-pollinated cultivars had significantly lower yield and oil content but significantly greater protein content than hybrid cultivars. There was also a strong negative correlation between seed oil and seed protein and the linear models were significant (r = 0.88, p \u3c 0.0001 for Year 1; r = 0.85, p \u3c 0.0001 for Year 2). Recommended winter canola cultivars include Exp1302 and Hekip

    ‘Agents-in-focus’ and ‘Agents-in-context’: The strong structuration analysis of central government accounting practices and reforms in Nepal

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    Drawing on Stones’ (2005) strong structuration theory, the paper unfolds why and how the key stakeholders of central government accounting in Nepal are involved in the reproduction of routinised accounting practices, resisting the externally-propagated changes. Government accountants (the agents-in-focus) through their capability to control the budget routines have enjoyed a powerful social position in their position–practice relations with the agents-in-context, i.e. professional accountants and international consultants, higher-level officers and administrators, auditors, and politicians. Social position along with historically-imbued dispositions and their conduct and context analysis have enabled government accountants to strategically exercise their agency. Government accountants have articulated duality and a dialectic relation with the agents-in-context, which have resulted in the reproduction of everyday accounting practice and the resistance to the World Bank-led reforms, such as accrual accounting and, more recently, the Cash-Basis IPSAS

    Magnetic field reveals vanishing Hall response in the normal state of stripe-ordered cuprates

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    The origin of the weak insulating behavior of the resistivity, i.e. ρxxln(1/T)\rho_{xx}\propto\ln(1/T), revealed when magnetic fields (HH) suppress superconductivity in underdoped cuprates has been a longtime mystery. Surprisingly, the high-field behavior of the resistivity observed recently in charge- and spin-stripe-ordered La-214 cuprates suggests a metallic, as opposed to insulating, high-field normal state. Here we report the vanishing of the Hall coefficient in this field-revealed normal state for all T<(26)Tc0T<(2-6)T_{\mathrm{c}}^{0}, where Tc0T_{\mathrm{c}}^{0} is the zero-field superconducting transition temperature. Our measurements demonstrate that this is a robust fundamental property of the normal state of cuprates with intertwined orders, exhibited in the previously unexplored regime of TT and HH. The behavior of the high-field Hall coefficient is fundamentally different from that in other cuprates such as YBa2_2Cu3_3O6+x_{6+x} and YBa2_2Cu4_4O8_{8}, and may imply an approximate particle-hole symmetry that is unique to stripe-ordered cuprates. Our results highlight the important role of the competing orders in determining the normal state of cuprates.Comment: This is a post-peer-review, precopyedit version of an article published in Nature Communications. The final authenticated version is available online at: https://doi.org/10.1038/s41467-021-24000-

    Robust hybridization gap in the Kondo insulator YbB12 probed by femtosecond optical spectroscopy

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    In heavy fermions the relaxation dynamics of photoexcited carriers has been found to be governed by the low energy indirect gap Eg resulting from hybridization between localized moments and conduction band electrons. Here, carrier relaxation dynamics in a prototype Kondo insulator YbB12 is studied over a large range of temperatures and over three orders of magnitude. We utilize the intrinsic nonlinearity of dynamics to quantitatively determine microscopic parameters, such as electron-hole recombination rate. The extracted value reveals that hybridization is accompanied by a strong charge transfer from localized 4 f levels. The results imply the presence of a hybridization gap up to temperatures of the order of Eg/kB ≈ 200 K, which is extremely robust against electronic excitation. Finally, below 20 K the data reveal changes in the low energy electronic structure, attributed to short-range antiferromagnetic correlations between the localized levels

    The cost of cooking a meal. The case of Nyeri County, Kenya

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    Energy for cooking is considered essential in achieving modern energy access. Despite this, almost three billion people worldwide still use solid fuels to meet their cooking needs. To better support practitioners and policy-makers, this paper presents a new model for comparing cooking solutions and its key output metric: the 'levelized cost of cooking a meal' (LCCM). The model is applied to compare several cooking solutions in the case study area of Nyeri County in Kenya. The cooking access targets are connected to the International Workshop Agreement and Global Tracking Framework's tiers of cooking energy access. Results show how an increased energy access with improved firewood and charcoal cookstoves could reduce both household's LCCMs and the total costs compared to traditional firewood cooking over the modelling period. On the other hand, switching to cleaner cooking solutions, such as LPG- and electricity, would result in higher costs for the end-user highlighting that this transition is not straightforward. The paper also contextualizes the results into the wider socio-economic context. It finds that a tradeoff is present between minimizing costs for households and meeting household priorities, thus maximizing the potential benefits of clean cooking without dismissing the use of biomass altogether

    DNA end resection by Dna2–Sgs1–RPA and its stimulation by Top3–Rmi1 and Mre11–Rad50–Xrs2

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    The repair of DNA double-strand breaks (DSBs) by homologous recombination requires processing of broken ends. For repair to start, the DSB must first be resected to generate a 3′-single-stranded DNA (ssDNA) overhang, which becomes a substrate for the DNA strand exchange protein, Rad51 (ref. 1). Genetic studies have implicated a multitude of proteins in the process, including helicases, nucleases and topoisomerases. Here we biochemically reconstitute elements of the resection process and reveal that it requires the nuclease Dna2, the RecQ-family helicase Sgs1 and the ssDNA-binding protein replication protein-A (RPA). We establish that Dna2, Sgs1 and RPA constitute a minimal protein complex capable of DNA resection in vitro. Sgs1 helicase unwinds the DNA to produce an intermediate that is digested by Dna2, and RPA stimulates DNA unwinding by Sgs1 in a species-specific manner. Interestingly, RPA is also required both to direct Dna2 nucleolytic activity to the 5′-terminated strand of the DNA break and to inhibit 3′ to 5′ degradation by Dna2, actions that generate and protect the 3′-ssDNA overhang, respectively. In addition to this core machinery, we establish that both the topoisomerase 3 (Top3) and Rmi1 complex and the Mre11–Rad50–Xrs2 complex (MRX) have important roles as stimulatory components. Stimulation of end resection by the Top3–Rmi1 heterodimer and the MRX proteins is by complex formation with Sgs1 (refs 5, 6), which unexpectedly stimulates DNA unwinding. We suggest that Top3–Rmi1 and MRX are important for recruitment of the Sgs1–Dna2 complex to DSBs. Our experiments provide a mechanistic framework for understanding the initial steps of recombinational DNA repair in eukaryotes
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