Constraining the nature of dark energy using the Square Kilometer Array Telescope

We investigate the potential of the Square Kilometer Array Telescope (SKA) to constrain the sound speed of dark energy. The Integrated Sachs Wolfe (ISW) effect results in a significant power spectrum signal when Cosmic Microwave Background (CMB) temperature anisotropies are cross-correlated with galaxies detectable with the SKA in H  i . We consider using this measurement, the autocorrelation of H  i galaxies and the CMB temperature power spectrum to derive constraints on the sound speed. We study the contributions to the cross-correlation signal made by galaxies at different redshifts and use redshift tomography to improve the signal-to-noise. We use a  χ²  analysis to estimate the significance of detecting a sound speed different from that expected in quintessence models, finding that there is potential to distinguish very low sound speeds from the quintessence value.     

中子活化测井在萤石矿勘探中应用效果

本文简要叙述了中子活化测井原位测定萤石矿(CaF_2)含量的原理及方法技术,以及在两个萤石矿区试生产的成果实例。并着重指出: 1.该方法适用于各种不同类型的萤石矿。选择F作为CaF_2的特征指示元素,在萤石矿无其它元素干扰,方法反映单解。 2.工作证明:该方法可防止由于岩矿心破碎造成的地质取心中漏失的矿体,发现地质工作未确定的薄矿层。并能提供CaF_2含量。 3.在取心率很低的钻孔,提供了真实可靠的CaF_2含量和矿层上下顶板确切位置,避免了钻孔报废、取得了良好的经济效益。最后文章指出:该方法的精度、灵敏度和工作效率完全满足生产工作的需要。     

基于iBeacon的精细室内定位方法研究

苹果公司发布的i Beacon作为一种粗精度位置感知服务体系,得到了广泛关注。针对更精细的广域位置服务,提出了基于i Beacon的无线指纹定位方法,并给出了图书馆的位置服务示例。     

Optimisation of the Population Monte Carlo algorithm: Application to constraining isocurvature models with cosmic microwave background data

We optimise the parameters of the Population Monte Carlo algorithm using numerical simulations. The optimisation is based on an efficiency statistic related to the number of samples evaluated prior to convergence, and is applied to a D ‐dimensional Gaussian distribution to derive optimal scaling laws for the algorithm parameters. More complex distributions such as the banana and bimodal distributions are also studied. We apply these results to a cosmological parameter estimation problem that uses CMB anisotropy data from the WMAP nine‐year release to constrain a six parameter adiabatic model and a fifteen parameter admixture model, consisting of correlated adiabatic and isocurvature perturbations. In the case of the adiabatic model and the admixture model we find that the number of sample points increase by factors of 3 and 20, respectively, relative to the optimal Gaussian case. This is due to degeneracies in the underlying parameter space. The WMAP nine‐year data constrain the admixture model to have an isocurvature fraction of 36.3 ± 2.8 %. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

土壤湿度对卫星辐射率资料直接同化的影响

本研究利用WRF模式及其三维变分同化系统实现了对NOAA-16 AMSU-A微波资料的直接同化,针对2010年6月19日江西地区的一次强降水过程开展模拟与同化试验,并利用中国区域土壤湿度同化系统(CLSMDAS—China Land Soil Moisture Data Assimilation System)输出的土壤湿度值替换NCEP(National Centers for Environmental Prediction)资料中的土壤湿度,研究土壤湿度初值对辐射率资料直接同化中观测场与背景场偏差调整的影响。结果表明:采用CLSMDAS输出土壤湿度初值条件下模拟的亮温值与实际观测值更为接近,经过质量控制和偏差订正后更多的观测资料能够进入到同化系统中,说明改进的土壤湿度初值条件下观测算子的计算值得到正的调整,对低层地表通道的改进效果明显,尤其以50.3 GHz的窗区通道3的结果最为理想;针对此次强降水过程中24 h累积降水分布的模拟结果,CLSMDAS输出土壤湿度初值条件下同化AMSU-A资料,能够较为准确的把握整个雨带的走向、大雨以上级别降水的落区范围、降水中心落区及强度等。说明准确的土壤湿度初值能够改进卫星辐射率资料的同化结果,进而提高数值模式的模拟预报能力。     

Lookback time as a test for f(R) gravity in the Palatini approach

We use the recently released data of lookback time (LT)-redshift relation, the cosmic microwave background shift parameter and the baryon acoustic oscillation measurements to constrain cosmological parameters of f (R) gravity in the Palatini formalism by considering the f (R) form of type (a) f (R) = R β/Rn and (b) f (R) = R + α ln R β. Under the assumption of a Friedmann-Robertson-Walker universe, we achieved the best fitting results of the free parameters (Ωm0, n) for (a) and (Ωm0, α) for (b). We find tha...     

青蛤(Cyclina sinensis)cDNA文库构建及免疫相关因子基因的筛选

在鳗弧菌侵染下,利用SMART方法构建了青蛤的cDNA文库,并采用高通量测序方法和BLASTX比对筛选出ESTs及免疫相关因子的基因.结果表明,所构建的cDNA文库的库容量为1.12×106,插入片段均在500bp以上;大于100bp的有效ESTs序列1113条,平均长度725bp,拼接后获得一致性序列420条,其中包括126个叠联群和294个单拷贝EST,BLASTX比对后获得注释序列271条,进一步筛选获得青蛤免疫相关因子基因序列45条,为克隆其免疫防御相关因子的基因提供了重要的基础.     

鲁西北西向断裂系与沂沭断裂带晚中生代演化关系及其动力学背景探讨

晚中生代是华北地块构造演化的转折时期。由出露于沂沭断裂带、鲁西地体、鲁东地体的中生代地层、岩浆,结合断裂活动年代学、区域地质等资料分析,可以将沂沭断裂带晚中生代构造演化划分出距今约160Ma、130～110Ma、90～80Ma等3个关键时期,并分别与左行压剪、左行张剪、右行压剪构造活动相对应。晚中生代沂沭断裂带与鲁西北西向断裂系间的几何学、运动学、年代学的共轭匹配关系表明,它们为特定构造动力学背景下形成的一组共轭断裂系。同时对鲁东地体晚中生代构造演化、鲁东北西向断裂系特征,以及沂沭断裂带、北西向断裂系晚中生代构造演化的动力学背景进行探讨。