358 research outputs found

    Acetone Adsorption to Co3O4?111?Surface: A Density Functional Theory (DFT) Study

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    Acetone, as one of VOCs, is not only polluting to the environment, but also harmful to humans. Therefore, detecting acetone is an important topic in the field of gas sensing. The carbonyl functional group determines the chemical properties of acetone. Aldehydes also contain carbonyl functional group. In this paper, we have calculated adsorption energy, adsorption distance and transfer charge by DFT. The results showed that the top of Co3+ on Co3O4 (111) surface has the best selectivity for sensing acetone. Our study contributes to the further study of the sensing properties of p-type metal oxide semiconductor sensors

    A model-driven deep reinforcement learning heuristic algorithm for resource allocation in ultra-dense cellular networks

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    Resource allocation in ultra dense network (UDN) is an multi-objective optimization problem since it has to consider the tradeoff among spectrum efficiency (SE), energy efficiency (EE) and fairness. The existing methods can not effectively solve this NP-hard nonconvex problem, especially in the presence of limited channel state information (CSI). In this paper, we investigate a novel model-driven deep reinforcement learning assisted resource allocation method. We first design a novel deep neural network (DNN)-based optimization framework consisting of a series of Alternating Direction Method of Multipliers (ADMM) iterative procedures, which makes the CSI as the learned weights. Then a novel channel information absent Q-learning resource allocation (CIAQ) algorithm is proposed to train the DNN-based optimization framework without massive labeling data, where the SE, the EE, and the fairness can be jointly optimized by adjusting discount factor. Our simulation results show that, the proposed CIAQ with rapid convergence speed not only well characterizes the extent of optimization objective with partial CSI, but also significantly outperforms the current random initialization method of neural network and the other existing resource allocation algorithms in term of the tradeoff among the SE, EE and fairness

    BP-NUCA: Cache Pressure-Aware Migration for High-Performance Caching in CMPs

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    As the momentum behind Chip Multi-Processors (CMPs) continues to grow, Last Level Cache (LLC) management becomes a crucial issue to CMPs because off-chip accesses often involve a big latency. Private cache design is distinguished by smaller local access latency, good performance isolation and easy scalability, thus is becoming an attractive design alternative for LLC of CMPs. This paper proposes Balanced Private Non-Uniform Cache Architecture (BP-NUCA), a new LLC architecture that starts from private cache design for smaller local access latency and good performance isolation, then introduces a low cost mechanism to dynamically migrate private blocks among peer private caches of LLC to improve the overall space utilization. BP-NUCA achieves this by measuring the cache access pressure level that each cache set experiences at runtime and then using the information to guide block migration among different private caches of LLC. A heavily accessed set, namely a set with high access pressure level, is allowed to migrate its evicted blocks to peer private caches, replacing blocks of sets which are with the same index and have low access pressure level. By migrating blocks from heavily accessed cache sets to less accessed cache sets, BP-NUCA effectively balances space utilization of LLC among different cores. Experimental results using a full system CMP simulator show that BP-NUCA improves the overall throughput by as much as 20.3 %, 12.4 %, 14.5 % and 18.0 % (on average 7.7 %, 4.4 %, 4.0 % and 6.1 %) over private cache, shared cache, shared cache management scheme UCP and private cache organization CC respectively on a 4-core CMP for SPEC CPU2006 benchmarks

    A generic object-oriented Tabu Search Framework

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    Operations Research/ Computer Science Interfaces Series32203-22

    Concentration-dependent effects of narciclasine on cell cycle progression in Arabidopsis root tips

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    <p>Abstract</p> <p>Background</p> <p>Narciclasine (NCS) is an Amaryllidaceae alkaloid isolated from <it>Narcissus tazetta </it>bulbs. NCS has inhibitory effects on a broad range of biological activities and thus has various potential practical applications. Here we examine how NCS represses plant root growth.</p> <p>Results</p> <p>Results showed that the inhibition of NCS on cell division in <it>Arabidopsis </it>root tips and its effects on cell differentiation are concentration-dependent; at low concentrations (0.5 and 1.0 μM) NCS preferentially targets mitotic cell cycle specific/cyclin complexes, whereas at high concentration (5.0 μM) the NCS-stimulated accumulation of Kip-related proteins (KRP1 and RP2) affects the CDK complexes with a role at both G1/S and G2/M phases.</p> <p>Conclusions</p> <p>Our findings suggest that NCS modulates the coordination between cell division and differentiation in <it>Arabidopsis </it>root tips and hence affects the postembryonic development of <it>Arabidopsis </it>seedlings.</p

    SrxTi1–xCoO3±δ Perovskite-like Catalysts with Enhanced Activity for Hydrogen Production

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    Autothermal reforming (ATR) of acetic acid (HOAc) is a promising and alternative route for hydrogen production from renewable resources, but catalyst deactivation caused by cobalt metal sintering and coking is a major concern in ATR. In this work, perovskite-like catalysts of the formula SrxTi1–xCoO3±δ (x = 0, 0.2, 0.5, and 0.8) were prepared by evaporation-induced self-assembly and then evaluated in ATR for hydrogen production. The SrxTi1–xCoO3±δ catalysts exhibited high activity and stability as well as 100 % conversion of HOAc. Additionally, the Co particles with strong metal-support interaction of SrTi(Co)O3 inhibited coking and agglomeration, and showed potential for hydrogen production by the ATR process

    Recombinant Cyclodextrinase from Thermococcus kodakarensis

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    A gene encoding a cyclodextrinase from Thermococcus kodakarensis KOD1 (CDase-Tk) was identified and characterized. The gene encodes a protein of 656 amino acid residues with a molecular mass of 76.4 kDa harboring four conserved regions found in all members of the α-amylase family. A recombinant form of the enzyme was purified by ion-exchange chromatography, and its catalytic properties were examined. The enzyme was active in a broad range of pH conditions (pHs 4.0–10.0), with an optimal pH of 7.5 and a temperature optimum of 65°C. The purified enzyme preferred to hydrolyze β-cyclodextrin (CD) but not α- or γ-CD, soluble starch, or pullulan. The final product from β-CD was glucose. The Vmax and Km values were 3.13 ± 0.47 U mg−1 and 2.94 ± 0.16 mg mL−1 for β-CD. The unique characteristics of CDase-Tk with a low catalytic temperature and substrate specificity are discussed, and the starch utilization pathway in a broad range of temperatures is also proposed

    Toward Low‐Temperature Zinc‐Ion Batteries: Strategy, Progress, and Prospect in Vanadium‐Based Cathodes

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    Low-temperature vanadium-based zinc ion batteries (LT-VZIBs) have attracted much attention in recent years due to their excellent theoretical specific capacities, low cost, and electrochemical structural stability. However, low working temperature surrounding often results in retarded ion transport not only in the frozen aqueous electrolyte, but also at/across the cathode/electrolyte interface and inside cathode interior, significantly limiting the performance of LT-VZIBs for practical applications. In this review, a variety of strategies to solve these issues, mainly including cathode interface/bulk structure engineering and electrolyte optimizations, are categorially discussed and systematically summarized from the design principles to in-depth characterizations and mechanisms. In the end, several issues about future research directions and advancements in characterization tools are prospected, aiming to facilitate the scientific and commercial development of LT-VZIBs
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