213 research outputs found

    Putting a Slug to Work

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    In this article, the authors explore various uses of inexpensive embedded Linux devices such as the Linksys NSLU2 ( slug ). Embedded computing is a topic of growing interest. Although novel architectures such as cell processors, graphics processors (GPUs), and FPGAs are growing in popularity, conventional microproessor designs such as Intel\u27s Xscale (ARM) and Atom pack a punch in a small footprint, not to mention being widely supported by commodity operating system and development tools. We\u27re convinced that this entire space is a tool worth keeping in the scientific programmer\u27s and software developer\u27s toolchests

    Indicator Candidate Traits for Autonomous Fruit Set Ability Under High Temperatures in Capsicum

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    “Autonomous fruit set” refers to self-pollination and fruit set without pollen vectors such as vibration or insects. Autonomous fruit set under high-temperature stress is an important breeding goal as climate change can reduce fruit yields in Capsicum. We screened Capsicum cultivars for autonomous fruit set ability in a greenhouse environment and investigated pollen germination, viability, pollen grains number, chlorophyll fluorescence (Fv/Fm), style length, anther cone length, and anthesis stage under high temperatures in order to identify indicator traits for screening more genotypes with autonomous fruit set ability. The fruit set of the ‘Takanotsume’ (57.7 ± 20.6%) and ‘Goshiki Kyokko’ (52.2 ± 14.2%) cultivars (both C. annuum) were higher than those of other cultivars. Correlation analysis showed that pollen germination had the highest correlation with fruit set in C. annuum cultivars (r = 0.63). These results indicate that ‘Takanotsume’ and ‘Goshiki Kyokko’ are useful cultivars for novel breeding programs focusing on autonomous fruit sets under high temperatures, and pollen germination in C. annuum was a convincing candidate for an indicator trait of autonomous fruit set ability under high temperatures

    MIG-seq is an effective method for high-throughput genotyping in wheat (Triticum spp.)

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    MIG-seq (Multiplexed inter-simple sequence repeats genotyping by sequencing) has been developed as a low cost genotyping technology, although the number of polymorphisms obtained is assumed to be minimal, resulting in the low application of this technique to analyses of agricultural plants. We applied MIG-seq to 12 plant species that include various crops and investigated the relationship between genome size and the number of bases that can be stably sequenced. The genome size and the number of loci, which can be sequenced by MIG-seq, are positively correlated. This is due to the linkage between genome size and the number of simple sequence repeats (SSRs) through the genome. The applicability of MIG-seq to population structure analysis, linkage mapping, and quantitative trait loci (QTL) analysis in wheat, which has a relatively large genome, was further evaluated. The results of population structure analysis for tetraploid wheat showed the differences among collection sites and subspecies, which agreed with previous findings. Additionally, in wheat biparental mapping populations, over 3, 000 SNPs/indels with low deficiency were detected using MIG-seq, and the QTL analysis was able to detect recognized flowering-related genes. These results revealed the effectiveness of MIG-seq for genomic analysis of agricultural plants with large genomes, including wheat

    Proposal and Demonstration of Free-Space Optical Communication Using Photonic Crystal Surface-Emitting Lasers

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    We propose and demonstrate free-space optical (FSO) communication using photonic crystal surface-emitting lasers (PCSELs). Unlike other types of conventional semiconductor lasers, such as edge-emitting lasers (EELs) and vertical-cavity surface-emitting lasers (VCSELs), PCSELs achieve much larger area single-mode coherent lasing, and this unique feature enables high-power (>watt) and lens-free operations at the same time. To date, these advantages have been recognized to be game changing, especially in light detection and ranging (LiDAR) and laser processing applications. In this work, we show that FSO communication can also benefit from these advantages of PCSELs; more specifically, conventional transmitters that include low-power semiconductor lasers, optical lenses, and fiber-based amplifiers could be replaced with a single PCSEL. Since fiber amplifiers usually consist of bulky components and have low conversion efficiencies, PCSELs can offer more space- and power-saving solutions. Moreover, the narrow beam divergence angles directly obtained from large-area single-mode PCSELs can also eliminate the need for lens systems on the transmitter side. To experimentally verify these potential advantages, we performed FSO transmission experiments based on PCSELs and successfully transmitted 480-MHz and 864-MHz orthogonal frequency division multiplexed (OFDM) signals over 1.1 m using a 500-μm PCSEL in a lens-free transmitter configuration. We believe that PCSELs open new possibilities and choices in FSO communication

    Combination of solid state NMR and DFT calculation to elucidate the state of sodium in hard carbon electrodes

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    We examined the state of sodium electrochemically inserted in HC prepared at 700–2000 °C using solid state Na magic angle spinning (MAS) NMR and multiple quantum (MQ) MAS NMR. The 23Na MAS NMR spectra of Na-inserted HC samples showed signals only in the range between +30 and −60 ppm. Each observed spectrum was ascribed to combinations of Na+ ions from the electrolyte, reversible ionic Na components, irreversible Na components assigned to solid electrolyte interphase (SEI) or non-extractable sodium ions in HC, and decomposed Na compounds such as Na2CO3. No quasi-metallic sodium component was observed to be dissimilar to the case of Li inserted in HC. MQMAS NMR implies that heat treatment of HC higher than 1600 °C decreases defect sites in the carbon structure. To elucidate the difference in cluster formation between Na and Li in HC, the condensation mechanism and stability of Na and Li atoms on a carbon layer were also studied using DFT calculation. Na3 triangle clusters standing perpendicular to the carbon surface were obtained as a stable structure of Na, whereas Li2 linear and Li4 square clusters, all with Li atoms being attached directly to the surface, were estimated by optimization. Models of Na and Li storage in HC, based on the calculated cluster structures were proposed, which elucidate why the adequate heat treatment temperature of HC for high-capacity sodium storage is higher than the temperature for lithium storage
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