36 resultados para 1098

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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以基于高频电磁场的方形冷坩埚电磁连铸(4C过程)作为研究对象,导出以感应电流作为未知量的描述弯月面形状的流体和电磁等各个压力平衡的无量纲方程组,发展了基于等参变换的连续曲面近似弯月的模拟方法,在此基础上定量考查感应器电流强度、电流频率、感应位置及坩埚分片数等对弯月面形状的影响。

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Thermodynamics of the displacive mechanism of plate-shaped phase alpha(1) was analyzed in beta'Cu-Zn alloys. It was proposed that the displacive transformation of the alpha(1) plate took place in the solute-depleted region formed in the parent phase during the incubation period. The thermodynamic analysis indicated that the driving force of alpha(1) transformation, Delta G, increased with the reduction of x(d), the solute concentration of the depleted region. And, Delta G could overcome-the transformation barrier with solute depletion to a certain degree. In addition, x(d) was higher than the equilibrium concentration in the phase diagram. Therefore, the shear formation of alpha(1) plate in the solute-depleted region was thermodynamically supported.

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温度梯度法(TGT)生长的Al2O3晶体因石墨发热体在高温时的挥发和原料中过渡性金属离子的存在,晶体在不同部位呈现不同颜色,一般上部为浅红色,尾部为浅黄绿色,将TGT法生长的Al2O3晶体(Ф110×80mm^3)依次经过高温氧化气氛、高温还原气氛脱碳、去色退火实验,即“两步法”退火实验,晶体变成无色、透明,经测试,Al2O3晶体的完整性、光学透过率和光学均匀性均有显著提高。

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Navigated transcranial magnetic stimulation (TMS) combined with diffusion-weighted magnetic resonance imaging (DW-MRI) and tractography allows investigating functional anatomy of the human brain with high precision. Here we demonstrate that working memory (WM) processing of tactile temporal information is facilitated by delivering a single TMS pulse to the middle frontal gyrus (MFG) during memory maintenance. Facilitation was obtained only with a TMS pulse applied to a location of the MFG with anatomical connectivity to the primary somatosensory cortex (S1). TMS improved tactile WM also when distractive tactile stimuli interfered with memory maintenance. Moreover, TMS to the same MFG site attenuated somatosensory evoked responses (SEPs). The results suggest that the TMS-induced memory improvement is explained by increased top-down suppression of interfering sensory processing in S1 via the MFG-S1 link. These results demonstrate an anatomical and functional network that is involved in maintenance of tactile temporal WM. (C) 2009 Elsevier Inc. All rights reserved.

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查对中国南部赤腹松鼠标本(40l号)的基础上,发现分布于云南东北部昭通地区的赤腹松鼠与赤腹松 鼠其他亚种有明显的区别。毛色特征:背部棕黄色,背中央区域稍带黑色;腹部至前胸栗红色;喉、颏部棕灰色; 尾毛背腹无明显差异,尾毛末端棕黄、次末端黑,尾末端具棕黄色(稍黄白)区域;前后足背棕褐色,稍带黑色。 进一步对头骨可量性状数据进行分析(差异系数),结果表明:分布于该地区的赤腹松鼠分别与赤腹松鼠其他13个 亚种两两之间至少有一项差异系数大于1.28,系一新亚种c蹴f眦i珏r猫e唧如me谢z,啪t撕g啪s泌s妇p.nov.。

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进化生物学研究表明,快速生长赋予生物的优势与劣势之间存在权衡.硬骨鱼类的生长率与游泳能力之间也存在这种权衡.本研究提出假说认为,快速生长将导致转基因鱼游泳能力减弱.比较F3代转“全鱼”生长激素基因黄河鲤与其对照鱼的生长和临界游泳速度,表明转基因鱼的平均体重是对照鱼的1.4~1.9倍,平均特定生长率比对照鱼高出6%~10%,而其绝对临界游泳速度和相对临界游泳速度的平均值分别比对照鱼低22%和24%.本研究暗示,具有快速生长效应的转基因黄河鲤表现出低劣的游泳能力,这也证实了生长率和游泳能力之间存在权衡,即同一

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Apo-14 is a fish-specific apolipoprotein and its biological function remains unknown. In this study, CagApo-14 was cloned from gibel carp (Carassius auratus gibelio) and its expression pattern was investigated during embryogenesis and early larval development. The CagApo-14 transcript and its protein product were firstly localized in the yolk syncytial layer at a high level during embryogenesis, and then found to be restricted to the digestive system including liver and intestine in later embryos and early larvae. Immunofluorescence staining in larvae and adults indicated that CagApo-14 protein was predominantly synthesized in and excreted from sinusoidal endothelial cells of liver tissue. Morpholino knockdown of CagApo-14 resulted in severe disruption of digestive organs including liver, intestine, pancreas and swim bladder. Moreover, yolk lipid transportation and utilization were severely affected in the CagApo-14 morphants. Overall, this data indicates that CagApo-14 is required for digestive system organogenesis during fish embryogenesis and larval development.

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为解决传统的文档分类方法和手工分类方法都不适宜于处理查询分类的问题,提出了一种基于Web的自动构建特定主题的语义词典的方法来分类搜索查询,通过基于主题的Web信息采集和bootstrapping,由某个主题的少量关键词逐步扩充,最终得到该主题的语义词典及词典中每个单词的相对词频.Web中信息的冗余和各主题语义上的差别使各主题的语义词典中单词的种类和数量存在很大差异,这种差异可以用来对用户的搜索查询进行分类.实验结果表明,利用语义词典可以较准确地将用户的查询分类,同时该分类方法基本上不需要人工介入,且可适应搜索查询覆盖面广和实时性强的特点,较好地解决了搜索查询分类的问题.

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高效燃油节油剂的研制及中试规模生产工艺研究李蒙俊,何向红中国科学院广州能源研究所一、前言我国燃油改进剂的产品很少,燃料油的用户普遍存在燃烧不完全,热效率抵的缺点,造成燃料油的浪费和空气污染。目前国内仅有“乳化剂”,即用加入水的办法降低油耗,此种产品的...

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本文提出了重力异常三维相关成像方法和重力梯度数据三维相关成像方法,并提出了基于异常分离的三维相关