为了将PTC（positive temperature coefficient）电子浆料以厚膜电路的形式制备在不锈钢基片上，并把不锈钢本体作为散热器，引出电极利用PTC效应制成可控电热元件．方法：提出基于1Cr18Ni9不锈钢基片的PTC厚膜电路的组成结构，并根据IC...为了将PTC（positive temperature coefficient）电子浆料以厚膜电路的形式制备在不锈钢基片上，并把不锈钢本体作为散热器，引出电极利用PTC效应制成可控电热元件．方法：提出基于1Cr18Ni9不锈钢基片的PTC厚膜电路的组成结构，并根据ICr18Ni9的膨胀系数和电路元件的电气特性实现了厚膜电路PTC电子浆料的应用设计技术．结果显示以PTC厚膜电路材料组成的可控电热元件，其功率密度高达200W／cm^2；其电阻膜层的表面加热速度可达200—300℃／s；其使用寿命达到1万小时以上．可见与传统的电热合金材料、陶瓷基片加热器以及元件组合的加热器相比，本实现技术电路具有功率密度大、响应速度快、加热温度可控等优点。展开更多
Persistent tapetal cell1(PTC1) plays a curial role in pollen development, and is thought to function as a transcriptional activator in rice. However, the molecular mechanism of PTC1 in regulating pollen development an...Persistent tapetal cell1(PTC1) plays a curial role in pollen development, and is thought to function as a transcriptional activator in rice. However, the molecular mechanism of PTC1 in regulating pollen development and its cis-elements are not well understood. We identified a novel weak male sterility mutant(ms92) which exhibited expanded tapetum and shrink pollen grains. Map-based cloning and allelic analysis suggested that the male sterility of ms92 was caused by a DNA fragment substitution in the promoter of PTC1. The decreased expression of MS92/PTC1 in ms92 and cis-element analysis indicated that the substituted sequence contained several potential binding cis-element of negative feedback. MS92/PTC1 was specifically expressed in tapetum and microspores at the young microspore stage, and its protein was localized in nucleus. We further found that MS92/PTC1 functions as a transcription activator by recognizing H3K4me3. Transcriptomic analysis revealed that a number of genes involved in tapetum degeneration and pollen wall formation were down-regulated in ms92, which are the potential targets of MS92/PTC1. The substitution fragment in MS92/PTC1 promoter was essential for pollen development, and we provided a novel mutant for further identifying the cis-elements in promoter and the molecular network of MS92/PTC1.展开更多
文摘为了将PTC（positive temperature coefficient）电子浆料以厚膜电路的形式制备在不锈钢基片上，并把不锈钢本体作为散热器，引出电极利用PTC效应制成可控电热元件．方法：提出基于1Cr18Ni9不锈钢基片的PTC厚膜电路的组成结构，并根据ICr18Ni9的膨胀系数和电路元件的电气特性实现了厚膜电路PTC电子浆料的应用设计技术．结果显示以PTC厚膜电路材料组成的可控电热元件，其功率密度高达200W／cm^2；其电阻膜层的表面加热速度可达200—300℃／s；其使用寿命达到1万小时以上．可见与传统的电热合金材料、陶瓷基片加热器以及元件组合的加热器相比，本实现技术电路具有功率密度大、响应速度快、加热温度可控等优点。
基金supported by the National Natural Science Foundation of China(Grant No.31301054)。
文摘Persistent tapetal cell1(PTC1) plays a curial role in pollen development, and is thought to function as a transcriptional activator in rice. However, the molecular mechanism of PTC1 in regulating pollen development and its cis-elements are not well understood. We identified a novel weak male sterility mutant(ms92) which exhibited expanded tapetum and shrink pollen grains. Map-based cloning and allelic analysis suggested that the male sterility of ms92 was caused by a DNA fragment substitution in the promoter of PTC1. The decreased expression of MS92/PTC1 in ms92 and cis-element analysis indicated that the substituted sequence contained several potential binding cis-element of negative feedback. MS92/PTC1 was specifically expressed in tapetum and microspores at the young microspore stage, and its protein was localized in nucleus. We further found that MS92/PTC1 functions as a transcription activator by recognizing H3K4me3. Transcriptomic analysis revealed that a number of genes involved in tapetum degeneration and pollen wall formation were down-regulated in ms92, which are the potential targets of MS92/PTC1. The substitution fragment in MS92/PTC1 promoter was essential for pollen development, and we provided a novel mutant for further identifying the cis-elements in promoter and the molecular network of MS92/PTC1.
文摘以 Srx Pb1 - x Ti O3为基料 ,液相掺杂一定量的 Y和 Si,采用传统固相合成工艺方法制备出了具有明显 V型阻温特性的半导体热敏电阻 ,通过扫描电镜形貌观察、R- T特性测试及复阻抗分析表明 ,Srx Pb1 - x Ti O3陶瓷的阻温特性明显受半导化程度的影响 ,居里点以下的 NTC效应往往随着半导化程度的提高而降低。掺杂玻璃相物质Si(OC2 H5 ) 4能增强 Srx Pb1 - x Ti O3陶瓷 NTC效应 (t<TC) ,同时也造成了室温电阻率的升高 ,但掺杂 Si与出现 NTC效应并没有必然的联系。作者认为在烧结过程中由于存在 Pb挥发 ,使 Srx Pb1 - x Ti O3陶瓷材料中出现了梯度 Pb2 +离子空位及缺陷缔合是 Srx Pb1 - x Ti O3基 V型热敏陶瓷材料产生显著 NTC效应主要原因 ,同时对 Srx Pb1 - x Ti
