高频感应炉燃烧后红外吸收法测定管线钢碳硫含量不确定度评定

依据JJF 1059.1—2012标准,分析了高频感应炉燃烧后红外吸收法测定管线钢中碳硫含量不确定度的影响因素,建立数学模型,并对管线钢中碳硫含量测定结果的不确定度进行评定,确定和计算测定过程中各个不确定度分量。对不确定度分量的数值进行比较发现,B类标准不确定度是分析碳硫含量不确定度的主要来源,仪器示值误差不确定度对总不确定度的影响最大。

河南渑池仰韶人遗址区黄土冲沟阶地的释光测年研究

地貌变迁与古人类活动的关系一直是地理学研究的一个重要科学问题。仰韶文化是黄河流域最为重要的新石器人类文明之一,文章以河南渑池仰韶遗址区内西沟冲沟为研究对象,尝试建立仰韶人类活动与遗址区内冲沟地貌形成的先后关系。渑池仰韶遗址区地处黄土高原东南缘黄土堆积区,文章利用释光测年方法测定了西沟冲沟阶地上覆堆积黄土的年代,粗略重建了阶地形成的时间为大约距今3万年和12万年前,分别对应深海氧同位素(MIS)3阶段和5阶段。而该时期渑池仰韶区域尚无古人类活动记录,所以释光测年结果证明仰韶遗址区内的冲沟完全是自然成因的,与遗址区仰韶人的地表活动无关。

岩石释光埋藏测年中砾石晒退程度的快速评估

信号晒退是释光测年的前提。最近几年发展起来的岩石释光埋藏测年技术,可以依据释光-深度曲线判断砾石样品释光信号晒退程度,这是该技术的一大优势之一。已有的测年实践显示,在不均匀晒退的沉积环境中,可能仅有少数砾石释光信号晒退良好,而大部分砾石年代高估。因此,非常有必要发展快速判断砾石释光信号晒退程度的方法,以提高测量效率。本文介绍了砾石释光信号晒退的几种常见情景及其筛选的理论基础,基于砾石释光信号由表及里晒退的事实,以及砾石表层剂量率变化大、测试深度需要、岩片平整度等的考虑,尝试将砾石表面约2 mm的释光信号与饱和释光信号进行对比,并结合统计分析方法(文中称“表_(-2 mm)/饱和信号法”),判断来自青藏高原东部横断山脉雀儿山北麓当子沟(32.1°N,98.9°E) 的典型不均匀晒退环境——冰川沉积的159个花岗岩冰水砾石的释光信号晒退程度。通过建立39根岩芯的完整释光-深度曲线,验证此方法可用于快速识别沉积前释光信号晒退良好的砾石。在此基础上,初步探讨了砾石释光信号晒退程度与沉积环境、砾石大小、磨圆度、球度、结构、砾石ab面方向间的关系,刻划释光信号晒退良好砾石的表观特征,以辅助岩石释光埋藏测年野外采样。

Effect of acupuncture on blood oxygen concentration in brain of rats with post-traumatic stress disorder based on functional near-infrared spectroscopy

Objective: To observe the effect of acupuncture on blood oxygen concentration in the brain of rats with post-traumatic stress disorder (PTSD) based on functional near-infrared spectroscopy (fNIRS), thus to reveal the mechanisms of acupuncture in intervening the brain function of PTSD rats. Methods: Sixty Sprague-Dawley (SD) rats were randomly divided into a blank group, a model group, a grasping group, a paroxetine group and an acupuncture group, with 12 rats in each group. Except the blank group, rats in the other groups all received incarceration plus electric shock for 7 d to prepare the PTSD animal model. One hour before the stress model was established, rats in each group received the desig nated in tervention: rats in the blank group and the model group did not receive any intervention;rats in the grasping group received grasping and fixation;rats in the paroxetine group received paroxetine hydrochloride solution by intragastric administration;and rats in the acupuncture group received acupuncture. Six-day treatme nt was a course, with 2 courses of treatme nt con ducted for a total of 12 d. After the modeli ng, rats in each treatment group received intervention for 5 dz and the fNIRS system was used to collect and record the changes in the concentrations of oxygenated hemoglobin (HbO2), deoxygenated hemoglobin (d-Hb) and total hemoglobin (t-Hb) of the involved rat's brain regions, and also to assess the brain function. Results: Compared with the blank group, the con centrati on of HbO2 was significa ntly in creased, the concen trati on of d-Hb was significa ntly decreased, and the concen tration of t-Hb was sign ifica ntly in creased in the model group and the graspi ng group after the in tervention, and the differ en ces were statistically significant (all P<0.01). Compared with the model group, the concentrations of HbO2, d-Hb and t-Hb in the grasping group did not change significantly (all P>0.05). Compared with the grasping group, the concentration of HbC^was significantly decreased, the concentration of d-Hb was significantly in creased, and the concen trati on of t-Hb was sign ifica ntly decreased in the paroxeti ne group and the acup un cture group, and the differences were statistically sigrdficant (all P<0.05). There were no significant differences in the concentrations of HbO2, d-Hb and t-Hb between the paroxetine group and the acupuncture group (all P>0.05). Con elusion: Acup un cture can regulate the blood oxyge n conce ntrati on in the brain of PTSD model rats, which may be an important mechanism of acupuncture in intervening the brain function in PTSD rats.