论瞬变电磁测深法的探测深度

文中分析了瞬变电磁发送线圈等效回路的暂态过程，得出线圈自感信号振幅的理论表达式，认为线圈自感信号的衰减不仅与时间有关，而且与等效回路的材料有关；计算了不同大小线圈的自感信号的幅值和衰减时间范围，得出了瞬变电磁测深法对地探测时存在一个最小深度的结论。由于电磁信号在地下传播时不断衰减，瞬变电磁测深法有一个最大探测深度。对大小不同的线框和不同介质电阻率等常用装置及典型地电情况，给出了估算瞬变电磁能探测的最小和最大探测深度的方法及估算结果。得出的结论对野外生产具有指导意义。     

弱膨胀土干湿循环直剪强度试验研究

为研究干湿循环作用下弱膨胀土的干湿循环直剪强度特征,采用南京胥河边坡弱膨胀土进行2种干密度下的干湿循环试验,对干湿循环后土体的剪应力、凝聚力及内摩擦角进行了分析,探究了膨胀土土样干湿循环后的直剪强度变化规律。试验结果表明膨胀土干湿循环后的裂缝扩展随着干湿循环次数的增加而增多、增宽,并呈现明显的不可逆性;土体的凝聚力随着干湿循环次数的增加而逐渐减小,且不同干密度土体干湿循环稳定后的凝聚力趋近于相同的稳定值;内摩擦角随干湿循环次数的增加变化规律不明显;直剪试验时的上覆压力对于土体抗剪强度测定的剪应力衰减影响明显,上覆压力越大,剪应力的衰减越小。在进行膨胀性土的边坡稳定性分析时,应采用低应力下的直剪强度参数作为分析参数,研究结论可为工程设计提供参考。     

泡沫压裂液稳定性及衰变机理研究

针对泡沫压裂液的在水流中稳定性能差的问题,通过对6种不同稳泡剂的泡沫压裂液的泡沫高度、泡沫排液量随时间的变化以及泡沫稳定系数(FSI)来评价不同类型稳泡剂的泡沫压裂液的稳定性,得到AEO-X2/C12醇复合稳泡剂(0.057%)和PAM(0.02%)的较好。利用电子显微镜观察泡沫形态随时间的变化研究了泡沫衰变的机理。     

低频波在油层中衰减系数预测模型的实验研究

利用室内实验所采集的低频水力振动在岩心中传播的时域分析、频域分析、振幅在岩心中的变化以及相关的实验数据,定性分析了振幅在岩心中的传播规律,并建立了振幅衰减率在x传播方向上变化的基本模型,得出衰减系数与振源振幅的关系式。应用量纲分析和相似原理建立了相关参数的函数关系式,对数据进行分析回归得出系数A、B的表达式,推导出低频波在油层中衰减系数的预测模型。应用此数学模型计算了低频水力脉冲压力波在油层渗流条件下的有效作用距离,所得结果与油田实际情况基本吻合。     

开路电压与太阳电池少子寿命关系的推导及其应用的研究

从理论上详细推导了晶体硅太阳电池在脉冲光照下,开路电压Voc(t)与少数载流子寿命的关系,同时研究了N-P结势垒电容放电时对Voc(t)的影响;从实验上验证了开路电压随时间的衰减关系,并运用该关系测量了硅太阳电池少数载流子寿命,测量结果较为准确.     

Novel models of intertemporal valuation: Past and future outcomes.

Temporal discounting refers to the reduction in the present subjective value of an outcome as a function of the temporal distance to that outcome. Though a number of mathematical models have been proposed to describe this time/value relationship, this search has largely excluded insights from the literature on memory decay. This study examines the utility of memory decay models by comparing the fits of 4 of these models to fits from established temporal discounting models using past and future temporal discounting data. These results (a) suggest that a single model describes valuation of both future and past outcomes; (b) indicate the exponential-power model, from memory decay literature, is statistically superior in fitting discounting data from both past and future outcomes; and (c) support the advancing perspective of the psychological interconnectedness of the future and past. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

High purity pion beam at TRIUMF

An extension of the TRIUMF M13 low-energy pion channel designed to suppress positrons based on an energy-loss technique is described. A source of beam channel momentum calibration from the decay π⁺→e⁺ν is also described.     

脉冲时间序列采集分析器的研制与验证

介绍了脉冲时间序列采集器(TSA)的研制及实验验证。该仪器采用FPGA和DSP技术实现了三通道并行、最高定时精度5ns、最高计数容量109的脉冲序列采集存储。根据Rossi-α原理编制软件算法实现了在线和离线测量。该仪器应用于核装置瞬发中子衰减常数测量的实验验证,测量结果与Rossi-α测量结果一致。     

球床模块式高温气冷堆失冷事故特性研究

利用高温气冷堆专用系统分析软件THERMIX程序,对球床模块式高温气冷堆(HTR-PM)失冷失压和失冷不失压事故的动态特性进行了研究,分析了堆芯功率、燃料最高温度及堆舱水冷壁余热载出功率等关键参数的变化过程,并对影响余热排出功率和燃料最高温度的不确定性进行了评价.研究结果表明,在失冷事故下,堆芯余热可通过热传导、辐射和自然对流等非能动方式传至最终热阱大气,燃料元件和压力容器等重要部件的最高温度均在设计限值内.这为HTR-PM保持模块式高温气冷堆固有安全性不变的同时实现单堆250 MW的功率方案奠定了基础,也为后续高温气冷堆电站示范工程进一步的深入设计研究提供了依据.     

Evaluation of Proliferation Resistance of Plutonium Based on Decay Heat

The present paper is prepared for the peaceful use of nuclear energy. Proliferation resistance of plutonium can be enhanced by increasing the decay heat of plutonium. For example, it can be enhanced by increasing the isotopic fraction of ²³⁸Pu, which has the largest decay heat among plutonium isotopes. In the present paper, the proliferation resistance of plutonium was evaluated based on decay heat with a physical assessment model. New criteria were proposed to evaluate the proliferation resistance based on isotopic compositions of plutonium from the viewpoint of decay heat. The present criteria were applied to evaluate the proliferation resistance of plutonium produced in typical Light Water Reactor and Fast Breeder Reactor based on an evaluation function “Attractiveness” as case studies.