986 resultados para 405
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The status of the HIRFL (Heavy Ion Facility in Lanzhou) - Cooler Storage Ring (CSR) at the IMP is reported. The main physics goals at the HIRFL-CSR are the researches on nuclear structure and decay property, EOS of nuclear matter, hadron physics, highly charged atomic physics, high energy density physics, nuclear astrophysics, and applications for cancer therapy, space industries, materials and biology sciences. The HIRFL-CSR is the first ion cooler-storage-ring system in China, which consists of a main ring (CSRm), an experimental ring (CSRe) and a radioactive beamline (RIBLL2). The two existing cyclotrons SFC (K=70) and SSC (K=450) are used as its injectors. The 7MeV/u12C6+ ions were stored successfully in CSRm with the stripping injection in January 2006. After that, realized were the accelerations of C-12(6+), Ar-36(18+), Kr-78(28+) and Xe-129(27+) ions with energies of 1GeV/u, 1GeV/u, 450 MeV/u and 235 MeV/u, respectively, including accumulation, electron cooling and acceleration. In 2008, the first two isochronous mass measurement experiments with the primary beams of Ar-36(18+) and Kr-78(28+) were performed at CSRe with the Delta p/p similar to 10(-5).
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Well-aligned TiO2/Ti nanotube arrays were electrochemically formed in a HF solution for different anodization times. Field emission scanning electron microscopy (FE-SEM) images reveal that anodization time had a great influence on the morphology of TiO2/Ti nanotube arrays. The composition of resulting nanotubes was analyzed by X-ray photoelectron spectroscopy (XPS). Field emission properties of the prepared samples with different morphologies were investigated by the Fowler-Nordheim (F-N) theory. The results indicate that the morphology can affect field emission behaviors. TiO2/Ti nanotube arrays with clear, uniform, and short nanotubes display moderate field emission properties, and have the better turn-on field of 4.6 V/mu m and good field emission stability. (C) 2010 Elsevier B.V. All rights reserved.
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Polypyrrole nanostructure arrays, including simultaneously large quantities of nanowires and small quantities of partially filled nanotubules have been electrochemically synthesized in home-made etched ion-track polycarbonate (PC) templates. Diameter of the prepared nanostructures varies from 45 to 320 nm with their lengths up to 30 microns. Morphological studies of these nanostructures were performed by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM) and Raman spectroscopy. While optical absorption properties were studied by ultraviolet-visible-near infrared spectrophotometry (UV-vis-NIR). It has been observed that the absorption maximum of polypyrrole shifts to the longer wavelength side as the diameter of these nanostructures (nanowires and nanotubules) increases. (C) 2010 Elsevier B.V. All rights reserved.
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近玻尔速度高电荷态离子在物质表面诱发的溅射离子能谱研究在理论和实验上尚是一片空白。本工作针对溅射离子能谱测量,设计、建立了一台径向位置灵敏127o柱形静电离子能谱仪。该谱仪结合位置灵敏探测器,克服了传统静电谱仪只能通过扫描电场单次、单能量点取谱的缺陷,实现了分段取谱——单次可获取宽为0.85Ec ≤ E ≤ 1.15Ec的能谱,极大提高了实验测量效率。利用该谱仪,首次获得了0.8至1.8倍玻尔速度Ar7,8,9+离子与金属铍靶和高定向性石墨靶碰撞产生的溅射离子能谱(入射角45o ,出射角135o)。结果表明:1)能谱分布很宽,其峰值位于130eV至600eV之间,远大于线性级联碰撞区的几到十几eV;且峰位随入射离子速度增加向高能方向略有移动。2)铍靶的溅射能谱呈一个极不对称的峰分布——高能部分有很长的尾巴,下降趋势服从E-n分布;其能谱与入射离子速度关联很大,小于vBohr时指数n与线性级联碰撞接近,而大于vBohr时非线性贡献明显。3)石墨靶的能谱峰位与入射离子动能、势能相关;其谱形在上升到最大值后均出现一个很宽的平台,表明该系列碰撞系统中,非线性效应占主导
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研究了ArthrobacterK110 8乙内酰脲酶的反应条件 ,结果表明 ,K110 8乙内酰脲酶的最适反应温度为 5 5℃ ,最适pH为 7 0 ,Co2 + 和Fe2 + 对该酶有激活作用 ,而Ca2 + 有严重抑制作用。K110 8乙内酰脲酶的底物专一性较强 ,其最适底物为 5 苄基乙内酰脲 ,5 苯基乙内酰脲和 5 吲哚甲基乙内酰脲均不能作为其有效底物。对K110 8乙内酰脲酶立体反应机制研究结果表明 ,其乙内酰脲水解酶不具立体选择性 ,决定产物立体构型的酶是N 氨甲酰氨基酸水解酶。
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以红树莓全汁为原料,利用低温发酵技术从8株酿酒酵母中筛选出优良菌株Y164(S.cerevisiae Hansenvar ellipsoideus),同时研究了红树莓干酒的发酵工艺并对影响红树莓干酒品质的关键性工艺参数进行了优化。按照0.05%的比例向压榨后的果汁中添加果胶酶,并保温45℃作用2h后,采用正交试验法优化发酵条件,结果显示:初始糖度为20%,主发酵温度为18℃,添加亚硫酸的浓度为0.11g/L,酒醪液含酸量为7.0g/L,前期发酵时间7~12d,后发酵需12~16d。澄清处理采用明胶-丹宁复合澄清剂,最后得到具有红树莓独特风味和典型宝石红色、果香浓郁、口味纯正、澄清透明的优质红树莓干酒。
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细沟剥蚀土粒随着细沟股流中含沙量的增加而减少 ,这一概念已在一些侵蚀模型 (如 WEPP)中得到应用。用黄土高原一种典型的粉壤土 ,在 5种坡度 (5°,10°,15°,2 0°,2 5°) ,3种流量 (2 ,4,8L/m in)条件下进行了细沟侵蚀模拟试验 ,试验沟长 0 .5~ 8m。通过 40 5次试验 ,确定了不同坡度、入流量条件下 ,侵蚀产沙量与细沟长度的定量函数关系。在假定细沟径流和土壤侵蚀沿细沟的行为相同条件下 ,提出了一种计算含沙水剥蚀率的方法 ,并进一步表达了细沟剥蚀率随含沙量以及沟长变化的函数关系。实验结果在 15°,2 0°,2 5°时表现出很好的显著性
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本文报道了中国纤孔菌属两个新记录种,分别为芮克纤孔菌Inonotus rickii (Pat.) D.A.Reid和杨生纤孔菌Inonotus plorans (Pat.) Bondartsev & Singer。芮克纤孔菌采于海南省保亭县热带植物园,生长在橡胶树上,杨生纤孔菌Inonotus plorans发现于中国西北地区的新疆,生长在杨树上,本文根据中国的材料对这两个种进行了详细描述和显微结构绘图。
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Chinese Assoc Cryptol Res, State Key Lab Informat Secur, Inst Software, Grad Univ Chinese Acad Sci, Natl Nat Sci Fdn China
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针对陆地生态系统碳汇/源的时空格局、碳循环过程的驱动机制及未来情景等前沿科学问题,提出陆地碳循环研究的地球信息科学方法,采用陆地生态系统碳通量/储量与碳循环过程的综合网络观测、生物过程的适应性实验研究以及河流碳输运过程研究为支撑系统的自下而上途径、与以土地利用/土地覆被变化和对地观测数据生态参量反演为基础的自上而下研究途径、经相互验证和尺度转换模型实现有机结合的研究方法,开展综合观测、调查、比对分析、模拟和评价研究,把握陆地生态系统碳循环的格局与过程规律,辨析自然和人为因素对陆地生态系统碳循环过程的影响,探讨全球气候变化条件下陆地生态系统碳循环过程的演变趋势。
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To find the pathologic cause of the children's dental fluorosis in southwestern China, diet structure before the age of 6 and prevalence rate of dental fluorosis (DF) of 405 children were investigated, and the fluorine and arsenic content of several materials were determined. The prevalence rate of DF of children living on roasted corn before the age of 6 is 100% with nearly 95% having the mild to severe DF; while that of children living on non-roasted corn or rice is less than 5% with all having very mild DF. The average fluorine and arsenic concentration are 20.26 mg/kg and 0.249 mg/kg in roasted corn, which are about 16 times and 35 times more than in non-roasted corn, respectively. The average fluorine concentration is 78 mg/kg in coal, 1116 mg/kg in binder clay and 313 mg/kg in briquette (coal mixed with clay). The average arsenic concentration of coal is 5.83 mg/kg, the binder clay is 20.94 mg/kg, with 8.52 mg/kg in the briquette. Living on roasted corn and chili is the main pathologic cause of endemic fluorosis in southwestern China. The main source of fluorine and arsenic pollution of roasted corn and chill is the briquette of coal and binder clay. (C) 2010 Elsevier B.V. All rights reserved.