EFFECT OF THE RATIO Th/U ON TL DATING ACCURACY

ＥＦＦＥＣＴＯＦＴＨＥＲＡＴＩＯＴｈ／ＵＯＮＴＬＤＡＴＩＮＧＡＣＣＵＲＡＣＹ￥Ｐ．Ｌ．Ｌｅｕｎｇ（梁宝鎏）；ＭｉｃｈａｅｌＪ．Ｓｔｏｋｅｓ（ＤｅｐａｒｔｍｅｎｔｏｆＰｈｙｓｉｃｓａｎｄＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅ，ＣｉｔｙＰｏｌｙｔｅｃｈｎｉｃｏ...     

用αβ谱仪测量人工αβ放射性气溶胶体积活度的试验研究

本文介绍了用αβ谱仪系统同时测量αβ谱、实现Ｒｎ／Ｔｈ子体补偿、确定超铀α核素气溶胶体积活度及人工放射性气溶胶总β体积活度的技术途径。利用ＲａＡ、ＲａＣ′ａ峰的二段时间计数可确定空气中ＲａＡ、ＲａＢ、ＲａＣ的气溶胶体积活度，相应的，也能给出ＲａＢ、ＲａＣ对总β计数的贡献。根据一般环境条件下的平衡比，用ＴｈＣ′的。计数修正Ｔｈ子体对αβ测量的影响。￣［２３９］ｐｕ或／和￣［２４１］Ａｍ人工核素的α计数，可通过两段时间分别扣除ＲａＡ、ＲａＣ′拖尾的方法确定；β计数分别扣除Ｒｎ／Ｔｈ子体β贡献即可确定。在本文规定的测量条件下，对室内天然Ｒｎ子体水平在１５Ｂｑ／ｍ￣３以下，超铀α核素气溶胶体积活度的测量下限可达到０．１Ｂｑ／ｍ￣３；即使在７５Ｂｑ／ｍ￣３环境下，人工核素总β的测量下限也可达ｌＢｑ／ｍ￣３以下。     

钍归-化在盆地γ能谱资料处理中的应用

在应用γ能谱资料寻找砂岩型铀矿的过程中，要尽可能地消除非矿化因素引起的干扰，提取与铀矿化有关的信息。介绍了钍归-化的原理及特点，采用与矿化有关的元素迁移信息的钍归-化方法，分析了二连盆地东部的γ能谱资料，揭示了该区放射性元素的分布特征、地球化学作用和后期铀元素的迁移与富集。结合其他地质资料，分析了钾剩差的变异区（正、负高值区）及铀剩差正高值区形成的原因，同时指出了经过钍归-化处理所得到的铀剩差正高值区应为氧化与还原作用过渡带的直接指示，也是该区进一步寻找砂岩型铀矿的重要标志。     

鄱阳湖湖底沉积物放射性水平

本文报道了1985年鄱阳湖湖底沉积物放射性水平的调查结果。沉积物中 U、Th、~(226)Ra、~(40)(?)和~(137)Cs 的比活度分别为64.8、67.9,58.9、676.1和3.5Bq/kg;用~(137)Cs 测龄方法作了沉积物泥芯垂直深度的年代定位,由此得知1985—1958年对应深度沉积物中 U、Th、~(226)Ra 和~(40)K 的比活度与1957—1930年对应深度沉积物比较无显著性差异;U、Th 和~(226)Ra 的浓集因予分别为5.2×10~413.9×10~4和4.8×10~4L/kg。     

未知钍—铀比的误差分析

研究了在任意Th、U含量和Th-U比覆盖整个范围(即0≤Th/U≤∝)时总α计数率对年剂量的转换因子及其误差。结果表明,当不测定Th-U比而只测量总α计数率时,最终引起的年龄误差对0≤Th/U≤∝来说为±5.1％-±8.3％,对1.1≤Th/U≤9.5来说只有±2.5％％-±4.1％。     

Bare necessities: the argument for a ‘revenge porn’ exception in Section 230 immunity

‘Revenge porn’ is the online posting of nude or sexually explicit photographs or videos of a former lover without his or her consent. Despite the malicious intent behind revenge porn, victims are provided with little to no relief due to Section 230 of the Federal Communications Decency Act, also known as the ‘Good Samaritan’ provisions. Section 230 unambiguously provides blanket immunity for website operators and Internet service providers that feature user-generated content, including revenge porn.

In Section 1, I discuss the purpose of Section 230 of the Communication Decency Act. In Section 2, I analyze the legal impact of the blanket immunity established in Section 230. In Section 3, I examine the potential remedies already in existence for revenge porn victims and highlight their inadequacies. In Section 4, I argue Congress should create a narrow exception to Section 230 immunity specifically geared toward revenge porn. The exception would establish a definition of revenge porn, which would prevent over-deterrence. Additionally, the exception would institute a takedown procedure similar to the process found in the Digital Millennium Copyright Act. In creating a narrow exception, the spirit of Section 230 will remain while also providing adequate legal relief for victims of revenge porn.     

Non-polar nuclei in fungal microbial RNases

An application of a previously proposed method for the analysisof the non-polar structure of proteins is presented. A detailedanalysis of the composition and properties of non-polar nucleiand microclusters of fungal microbial ribonucleases has beenperformed on the basis of the 3-D structures of RNase T1 andrelated proteins. Three hydrophobic nuclei were found in thesestructures. It has been shown that all residues in non-polarnuclei have high homology ({small tilde}89%). Residues in thenuclei are practically fully buried in the interior of a molecule.Detailed analysis of non-polar nuclei properties shows thatthese nuclei determine the hydrophobic core of a protein andthe location and role of each residue in the non-polar interiorof proteins. In addition it was found that there are variableresidues not only on the surface of a protein but on the surfaceof the nuclei inside the protein and between the nuclei andthat there is a consistent region in all proteins, the hydrophobic-nuclei. An evaluation of the stability of non-polar nuclei,the conservation of their compositions and their positions inthe protein globule, allows one to assume that these three nucleiplay an important functional role in the stability and foldingof molecules of RNases and possibly can be considered as independentstructural elements of 3-D structures of these proteins.     

CR230－EP氯丁橡胶的应用

介绍ＣＲ２３０－ＥＰ氯丁橡胶进厂检验和车间工艺试验。     

热处理工艺对Ti-230合金薄板组织和性能的影响

研究了不同退火温度和退火时间对Ti-230钛合金板材显微组织和力学性能的影响。测试了不同退火工艺条件下合金薄板的强度和塑性。用金相显微镜和透射电镜观察了微观组织和析出相粒子Ti2Cu的分布。实验结果表明,随着退火温度从650℃升至790℃(保温30min),合金板材的抗拉强度从541MPa升到580MPa,延伸率从27.5%降到26%。在给定790℃,保温时间分别为5,15,30min条件下退火,其强度和延伸率变化不是十分明显。从OM和TEM对组织的观察得出,随着退火温度的升高,晶粒度明显增大,晶粒等轴化程度增加,析出的Ti2Cu粒子随退火温度的升高和保温时间的延长明显减少。采用790℃,30min退火工艺,其晶粒尺寸,Ti2Cu粒子的分布及Cu在基体中的固溶度可以达到良好的匹配,使合金获得最佳的力学性能。     

光纤陀螺随机误差特性ThêoH辨识

随机误差特性分析是光纤陀螺进入工程应用阶段的关键技术.针对Allan方差、总方差、Thêo1 (Theoretical variance #1)等分析方法的不足,以Thêo1为基础,通过偏差消除获得ThêoBR(Bias-removed ver?sion of Thêo1),并将其与Allan方差合成,得到光纤陀螺随机误差特性分析的ThêoH(Hybrid-ThêoBR)法.通过计算重叠Allan方差、总方差、Thêo1以及ThêoH的等效自由度,结合仿真和实测信号的随机误差特性分析实验,证明ThêoH法不仅提高了Allan方差估计的置信度,且解决了Thêo1估计有偏的问题,表明了该方法是目前能够有效辨识光纤陀螺随机误差特性的最佳方法.