物化型软岩包覆改性和改性机理

基于对已有软岩和软岩工程的研究方法、存在问题和软岩的物质组成、晶层结构与胀缩机理等的系统研究,提出了可以通过表面包覆改性实现物化型软岩工程稳定的新思路,并对物化型软岩的表面结构和性质进行了系统研究,给出了化学结构为Y-R-SiX3的有机硅化合物与物化型软岩表面反应的化学方程,为软岩和软岩工程稳定性的深入研究提供理论依据.     

八肽胆囊收缩素抗血清翻转针刺耐受的电生理学研究

动物整体水平研究证实，八肽胆囊收缩素抗血清（ＣＣＫ－ＡＳ）可翻转电针耐受，而ＣＣＫ－ＡＳ本身不影响基础痛阈。本文采用记录神经元放电的方法证明：脑室注射ＣＣＫ－ＡＳ能翻转对长时间电针产生耐受效应的大鼠丘脑束旁核痛兴奋神经元（ＰＥＮ）和痛抑制神经元（ＰＩＮ）的电活动，使电针镇痛效应重新出现。而脑室注射正常兔血清（ＮＲＳ）对产生电针耐受效应的ＰＥＮ和ＰＩＮ的电活动无影响。从细胞水平得到的这一结果与整体水平研究的证据相一致。提示，内源性ＣＣＫ－８参与电针耐受可能是电针镇痛受到拮抗的机制之一。这一发现同时为临床医学实践提供了进一步的依据。     

卫星定位误差的最优星座选择剖析

在分析定位误差的基础上,研究了星座最佳几何配置,以及几何位置相对较好、星的个数较少的4颗卫星的定位问题,并给出了星座的最佳几何分布与定位误差的关系仿真.结果表明,在卫星星座中,星的高度与分布的均匀性是决定星座几何精度的衰减因子,顶座星、底座星的仰角与方位角之差则是几何精度衰减因子的影响因素.通过计算和实验发现,在GPS系统的定位过程中,有一组最优的、由4颗卫星组成的几何配置星座,此时对应的几何精度衰减因子最小,为1.581 2.     

Epigenetic regulation of skin: focus on the Polycomb complex

Chromatin regulators have recently emerged as key players in the control of tissue development and tumorigenesis. One specific chromatin regulator, the Polycomb complex, has been shown to regulate the identity of embryonic stem cells, but its role in controlling fates of multipotent progenitors in developing tissues is still largely unknown. Recent findings have revealed that this complex plays a critical role in control of skin stem cell renewal and differentiation. Moreover, the expression of Polycomb complex components is often aberrant in skin diseases, including skin cancers. This review will detail recent findings on Polycomb control of skin and highlight critical unknown questions.     

低效稠油CO2复合吞吐参数优化

针对部分埋藏深、渗透率低、高温高盐等无法热采或化学驱的稠油油藏,部分油田采用了“CO2+增溶剂”的复合吞吐生产方式,并取得了一定效果。目前关于CO2吞吐方面的物模模拟实验无法满足复合吞吐的研究需要。本研究建立了一套基于吞吐补偿系统的CO2复合吞吐的物理模拟方法,开展了室内CO2 吞吐物理模拟实验,研究了增溶剂注入量、CO2注入量、注入方式等因素对吞吐效果的影响,同时进行了现场试验并进行了跟踪评价。结果表明：增溶剂注入浓度为5-10%、CO2与化学剂注入质量比为1:2.5~1:5、采用两段塞注入方式,提高采出程度最高。该方法有效的模拟了复合吞吐过程中的注入、焖井和产出过程,完全满足CO2复合吞吐的工艺参数优化的研究要求。     

流动场中能量问题的变分原理及其能量方程的有限单元离散

本文对流体的能量微分方程中线性微分算子进行了自伴性调整,提出了此问题的一个变分原理,给予了证明和有限单元离散,且对自伴性调整后的变分原理涉及到的数值问题进行了说明。     

A comparative study of global ionospheric responses to three great magnetic storms

Based on a large data base from 69 ionosonde stations distributed worldwide a comparative study is made on the global behavior of ionospheric responses to three great magnetic storms occurring nearly at low and high activity phase of the 22nd solar cycle. Depending on the season of storn occurrence, the global morphology of the ionospheric response to major magnetic storm is very different. For the February 1986 storm, hemispheric asymmetry of storm effects is remarkable, and positive storm effects are dominant in the winter hemisphere. Instead, for the two magnetic storms taking place near equinox in 1989, longlasting decreases in N_m were observed in both hemispheres Large-scale TIDs propagating equatorward were seen during the main phases of the October 1989 magnetic storm at evening-night sector. On the other hand, short-lasting positive storm effects appearing as wave-like disturbances in N_m were observed during the primary main phase of the 1986 storm in winter hemisphere. They seem to originate near the equatorial region and travel polarward. Supported by the National Natural Science Foundation of China and the Science Foundation of State Education Commitee of China Xu Jisheng: born in Nov. 1946, Professor     

煤与瓦斯突出区域预测集成专家系统的实现

以煤瓦瓦斯突出区域预测的灵敏指标为基础,建立了预测揄知识树。以专家系统开发工具ＶＰ－ＥＸＰＥＲＴ为支持环境,以“功能集成”为主导思想,以“总控调用”为结构特色,以“非直接耦合”模块间连接的纽带,建立了集单一预测系统、集成预测系统和辅助系统为一体的煤与瓦斯突出区域预测集成专家系统,预测精度和系统功能较以往的同类系统有明显改进和提高。     

水中氰化物的应急监测仪器分析方法

运用水质应急监测仪器对水中氰化物进行了分析研究,通过方法对照实验,确定对水中氰化物的应急监测的快速分析方法。这种方法以在无电源、无水源、无实验平台的现场快速分析水中的氰化物,分析一个样品的时间只需要32min,比常规分析时间缩短73％,并且可以达到常规分析所要求的准确和精密度。     

Optimal Power Control for OFDM Signals over Two-Way Relay with Physical Network Coding

This paper describes an optimal power allocation scheme for orthogonal frequency division multiple access two-way relay networks with physical network coding.The aim is to enhance the achievable sum rate of the terminals for a constrained total transmit power.Convex optimization is used to derive a closed-form solution for the power allocation between the relay node and the two terminals.This reduces the variable dimensionality of the objective function for the power assignment problem among multiple carriers when the total transmit power is constrained.This solution is then used to derive the optimal power control scheme.This method reduces the implementation complexity compared with the traditional resource allocation scheme.Numerical and simulation results show that the approach achieves almost the optimal sum rate and outperforms the fixed power assignment method with less computational load in various scenarios.