An 8.1 Ma calcite record of Asian summer monsoon evolution on the Chinese central Loess Plateau

IEECAS SKLLQG

The influence and chronological uncertainties of the 8.2 ka cooling event on continental climate records in China

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黄土高原8．1Ma以来方解石记录的夏季风演化

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Pollen record from red clay sequence in the central Loess Plateau between 8.10 and 2.60 Ma

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利用贺兰山北部树轮资料重建过去270年以来6-8月平均干燥指数

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黄土高原陇东盆地朝那红黏土8.1～2.6 Ma的孢粉记录

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~(16)O~(8+)注入小麦种子胚乳引起M_1代幼苗可溶性蛋白质的变化

通过控制单核能大小 ,将 1 6 O离子注入小麦种子胚乳 ,结果引起 M1 代幼苗可溶性蛋白质的较大变化。可溶性蛋白质电泳凝胶胶片的扫描曲线显示 :1 )在高剂量的处理中 ,有的峰消失 ;有的峰高于对照 ,中、高剂量值呈升高趋势 ;有的峰低于对照 ,中、高剂量值呈下降趋势。 2 )按分子量的大小将可溶性蛋白质分成 5个区段 ,并计算不同区段蛋白质组分的相对含量。结果表明 ,同对照相比 ,第 2区段的相对含量降低 (分子量较大区段 ) ,而第 5区段的相对含量升高 (分子量最小区段 )。 3 )同时也表明 ,低剂量效应表现异常。本文也讨论了诱变胚乳对胚作用的可能机理

ELV-8型加速管电子光学性能研究

ELV-8型加速器的加速管分为变梯度加速管段和等梯度加速管段两部分。阴极为六硼化镧平面阴极。电子束的聚焦采用变梯度场聚焦 ,使电子束成为层流束。电子枪的平面电极使得阴极发射面前的电场均匀 ,从而使得加速管的电子光学系统对初始条件不过于敏感 ,而便于电子枪的替换

~(16)O~(8+)离子辐照普通小麦引起幼苗可溶性蛋白质的不同变化

利用不同能量、不同剂量的1 6 O8+ 离子辐照春麦。处理方式为离子贯穿种子 (75MeV u)以及离子注入胚和胚乳等种子的不同部位。然后分析其幼苗的可溶性蛋白质 (solubleprotein) ,根据其分子量大小不同 ,将其划分为五个区段并计算各组分的相对含量 ,结果表明 :1 同对照相比 ,随着辐照剂量的增加 ,所有辐照材料 (包括贯穿和注入 )第二区段 (分子量较高区段 )蛋白质组分的相对含量下降 ;而第五区段 (分子量最小区段 )蛋白质组分的相对含量升高。 2 种子的贯穿处理 ,同时也引起第一区段 (分子量最高区段 )和第三区段蛋白质组分相对含量的下降以及第四区段的升高 ;其中第三、四区段的变化明显区别于注入效应。 3 注入胚和胚乳的区别在于后者第一区段蛋白质组分相对含量的较大下降和第五区段的较大提高。 4 小剂量辐照的材料 ,可溶性蛋白质组分的变化异常 ,可能与低剂量辐射兴奋效应有关。在讨论中提出了注入胚的即时效应与注入胚乳的后期效应。

小剂量~(16)O~(8+)离子预辐射减轻大剂量辐射所致小鼠睾丸组织损伤(英文)

为了了解小剂量重离子辐射诱导小鼠睾丸结构的适应性反应,采用小剂量(0.05Gy)~(16)O~(8+)离子照射B6C3F_1雄性小鼠睾丸。4h后,再给予2Gy~(16)O~(8+)离子照射。照射后第35天取材在光镜下观察睾丸结构。结果显示,大剂量(2Gy)照射明显损伤睾丸组织,主要表现为曲精细管直径几乎减小一半,精管内各发育阶段的生殖细胞减少或消失,特别是精原细胞几乎完全消失。而Leydig细胞和Sertoli细胞仅有轻度核固缩及胞浆减少。提示睾丸生殖细胞的辐射敏感性明显高于其间质组织细胞。预先给予小剂量(0.05Gy)照射可明显减轻随后大剂量(2Gy)辐射对睾丸组织的损伤。提示小剂量重离子辐射可诱导小鼠睾丸结构明显的适应性反应。

Low-lying non-normal parity states in B-8 measured by proton elastic scattering on Be-7

A new measurement of proton resonance scattering on Be-7 was performed tip to the center-of-mass energy of 6.7 MeV using the low-energy RI beam facility CRIB (CNS Radioactive Ion Beam separator) at the Center for Nuclear Study of the University of Tokyo. The excitation function of Be-7 + p elastic scattering above 3.5 MeV was measured Successfully for the first time, providing important information about the resonance structure of the B-8 nucleus. The resonances are related to the reaction rate of Be-7(p.gamma)B-8. which is the key reaction in solar B-8 neutrino production. Evidence for the presence of two negative parity states is presented. One of them is a 2(-) state observed as a broad s-wave resonance, the existence of which had been questionable. Its possible effects on the determination of the astrophysical S-factor of Be-7(p.gamma)B-8 at solar energy are discussed. The other state had not been observed in previous measurements, and its spin and parity were determined as 1(-). (C) 2009 Elsevier B.V. All rights reserved.

Experimental study of the beta-delayed neutron decay of N-21

The first spectroscopic study for the beta decay of N-21 is carried out based on beta-n, beta-gamma, and beta-n-gamma coincidence measurements. The neutron-rich N-21 nuclei are produced by the fragmentation of the E/A=68.8 MeV Mg-26 primary beam on a thick Be-9 target and are implanted into a thin plastic scintillator that also plays the role of beta detector. The time of flight of the emitted neutrons following the beta decay are measured by the surrounding neutron sphere and neutron wall arrays. In addition, four clover germanium detectors are used to detect the beta-delayed gamma rays. Thirteen new beta-delayed neutron groups are observed with a total branching ratio of 90.5 +/- 4.2%. The half-life for the beta decay of N-21 is determined to be 82.9 +/- 7.5 ms. The level scheme of O-21 is deduced up to about 9 MeV excitation energy. The experimental results for the beta decay of N-21 are compared to the shell-model calculations.