提出一种双通道16位串型数模转换器(Digital to Analog Converter,DAC)结构,该结构为电流舵与串电阻混合型DAC。设计采用4+6+6的分段方式,从结构角度能有效降低DAC的功耗,其中高4位采用串电阻型16选1的译码结构,中6位采用串电阻型64选1...提出一种双通道16位串型数模转换器(Digital to Analog Converter,DAC)结构,该结构为电流舵与串电阻混合型DAC。设计采用4+6+6的分段方式,从结构角度能有效降低DAC的功耗,其中高4位采用串电阻型16选1的译码结构,中6位采用串电阻型64选1的译码结构,低6位采用温度计电流舵译码结构。并利用Spectre工具仿真验证DAC的功能和性能。使用0.5μm CMOS工艺实现电路版图。在25℃环境温度下,仿真结果表明电流功耗为730μA,有效位数(ENOB)为15.19 bit,信噪比(SNR)为93.21 dB,总谐波失真(THD)为68.00 dB,无杂散动态范围(SFDR)为94.49 dB。展开更多
2008年全球金融危机后,国际社会愈发重视金融担保品在维护金融稳定中发挥的重要作用,新兴市场证券逐步走入国际视野。在此背景下,2021年,国际货币基金组织(IMF)发表了工作论文《新兴市场证券加入全球金融管网》(Emerging Market Securit...2008年全球金融危机后,国际社会愈发重视金融担保品在维护金融稳定中发挥的重要作用,新兴市场证券逐步走入国际视野。在此背景下,2021年,国际货币基金组织(IMF)发表了工作论文《新兴市场证券加入全球金融管网》(Emerging Market Securities Access to Global Plumbing),从金融担保品跨境转移的经济学视角,提出了对促进新兴市场证券加入全球金融管网的思考和建议。中央结算公司征得IMF授权,翻译该论文,希望为人民币债券担保品加入全球金融管网带来启发。展开更多
An es-t (early senescence-temporary) mutant, produced by ethylene methylsulfonate treatment of strain Nipponbare, was identified in rice. The leaves of es-t appeared yellow at the seedling stage, and had decreased chl...An es-t (early senescence-temporary) mutant, produced by ethylene methylsulfonate treatment of strain Nipponbare, was identified in rice. The leaves of es-t appeared yellow at the seedling stage, and had decreased chlorophyll content. Rust spots were found during growth in es-t, especially at the leaf margin and tip. The plants showed a typical early-senescence phenotype at the milky stage. The leaf surface of es-t appeared smoother than wild-type leaves under a scanning electron microscope, because the leaves lack siliceous protuberances around the stoma. Chloroplasts grow abnormally and are filled with many starch grains in es-t. Paraffin section analysis showed that the development of the sclerenchyma cells and vascular bundles were also abnormal in es-t. Genetic analysis indicated that es-t was controlled by a recessive gene, which was finely mapped to a 42-kb interval on chromosome 5. These results will facilitate the positional cloning and functional studies of the gene.展开更多
文摘【目的】叶片是水稻进行光合作用的主要场所,叶片颜色的变化与水稻的生长发育直接相关。发掘水稻叶色突变体,是水稻功能基因组学研究的重要遗传基础。【方法】利用EMS诱变日本晴获得一个能稳定遗传的淡绿叶突变体,暂命名为pgl11(pale green leaf 11)。在不同生育期测定野生型与突变体的叶绿素含量。在苗期,取野生型与突变体叶片进行叶绿体结构的透射电镜观察。在分蘖期,测定野生型与突变体的光合参数并观察气孔结构。在成熟期,测定野生型和pgl11的主要农艺性状。以pgl11为母本,南京6号为父本构建相应的F2群体,采用图位克隆的方法,对该基因进行定位。【结果】从苗期开始,突变体pgl11的每一片新叶均表现为淡绿色,叶绿素含量显著降低,叶绿体发育异常。随着叶片的生长,叶色由淡绿逐渐转绿,至抽穗期时叶绿素含量亦无明显差异。pgl11还表现光合速率、气孔导度明显下降,胞间CO_2浓度上升。扫描电镜观察发现,突变体pgl11的气孔发育异常。与野生型相比,突变体的农艺性状如株高、剑叶宽、二次枝梗数、每穗粒数、粒长、粒宽、千粒重以及结实率等均显著降低。对叶绿素合成、光合作用以及质体发育相关基因的表达量测定表明,突变体pgl11中参与叶绿体转录和翻译相关基因的表达量显著升高,而叶绿素合成和光合作用相关基因的表达量显著下降。遗传分析表明,该突变表型受一对隐性核基因控制。通过图位克隆的方法将该基因定位于第1染色体上的C6和C8标记之间,物理距离约为110 kb。【结论】该定位区间内未见有叶色相关基因报道,推测PGL11基因可能是一个新的水稻叶色基因。
文摘提出一种双通道16位串型数模转换器(Digital to Analog Converter,DAC)结构,该结构为电流舵与串电阻混合型DAC。设计采用4+6+6的分段方式,从结构角度能有效降低DAC的功耗,其中高4位采用串电阻型16选1的译码结构,中6位采用串电阻型64选1的译码结构,低6位采用温度计电流舵译码结构。并利用Spectre工具仿真验证DAC的功能和性能。使用0.5μm CMOS工艺实现电路版图。在25℃环境温度下,仿真结果表明电流功耗为730μA,有效位数(ENOB)为15.19 bit,信噪比(SNR)为93.21 dB,总谐波失真(THD)为68.00 dB,无杂散动态范围(SFDR)为94.49 dB。
文摘2008年全球金融危机后,国际社会愈发重视金融担保品在维护金融稳定中发挥的重要作用,新兴市场证券逐步走入国际视野。在此背景下,2021年,国际货币基金组织(IMF)发表了工作论文《新兴市场证券加入全球金融管网》(Emerging Market Securities Access to Global Plumbing),从金融担保品跨境转移的经济学视角,提出了对促进新兴市场证券加入全球金融管网的思考和建议。中央结算公司征得IMF授权,翻译该论文,希望为人民币债券担保品加入全球金融管网带来启发。
基金supported by the National Special Program for Research and Transgenic Plants (2011ZX08009-003)the National Key Basic Research Program of China (2007CB10920203)the National Natural Science Foundation of China (30971760)
文摘An es-t (early senescence-temporary) mutant, produced by ethylene methylsulfonate treatment of strain Nipponbare, was identified in rice. The leaves of es-t appeared yellow at the seedling stage, and had decreased chlorophyll content. Rust spots were found during growth in es-t, especially at the leaf margin and tip. The plants showed a typical early-senescence phenotype at the milky stage. The leaf surface of es-t appeared smoother than wild-type leaves under a scanning electron microscope, because the leaves lack siliceous protuberances around the stoma. Chloroplasts grow abnormally and are filled with many starch grains in es-t. Paraffin section analysis showed that the development of the sclerenchyma cells and vascular bundles were also abnormal in es-t. Genetic analysis indicated that es-t was controlled by a recessive gene, which was finely mapped to a 42-kb interval on chromosome 5. These results will facilitate the positional cloning and functional studies of the gene.
