Automatic data acquisition system and reconstruction algorithm for computerized ionospheric tomography

The design and operation features of the automatic data acquisition system for the low-latitude ionospheric tomography along the 120°E meridian are presented. The system, automatically collects the differential Doppler phase data, and GPS satellite beacon signal is simultaneously collected to achieve time synchronization of all recelvers in whole station-chain. An improved reconstruction algorithm of computerized ionospheric tomography is also proposed, in which calculating of the integral phase constant and choosing of the initial guess are integrated in the procedure of reconstruction and evaluated by the reconstructed image. Both numerical simulation examples and reconstructed results from observed data show that the new algorithm works reasonably and effectively with ionospheric CT problems. Foundation item: Supported by the National Natural Science Foundation of China (49584006) Biography: WU Xiong-bin (1968-), male, Ph. D candidate. Research direction: computerized ionospheric tomography.     

Construction and visualization of high-resolution three-dimensional anatomical structure datasets for Chinese digital human

The objective of the China Digital Human Project （CDH） is to digitize and visualize the anatomical structures of human body. In the project, a database with information of morphology, physical characteristics and physiological function will be constructed. The raw data of CDH which was completed in the Southern Medical University is employed. In Huazhong University of Science and Technology （HUST）, the frozen section images are preprocessed, segmented, labeled in accordance with the major organs and tissues of human beings, and reconstructed into three-dimensional （3D） models in parallel on high performance computing clusters （HPC）. Some visualization software for 2D atlas and 3D models are developed based on the new dataset with high resolution （0.1 mm× 0.1 mm × 0.2 mm）. In order to share, release and popularize the above work, a website （www.vch.org.cn） is online. The dataset is one of the most important parts in the national information database and the medical infrastructure.     

多孔介质模型的三维重构方法

建立准确的多孔介质模型在微观渗流机理的研究中具有重要意义.为了更加方便准确地建立多孔介质模型,总结了多孔介质模型重构的物理实验方法和数值重构方法,通过重构方法的优缺点对比及适用性分析,优选出马尔可夫链-蒙特卡洛方法(MCMC).针对3种不同性质的多孔介质,采用MCMC方法分别对其进行了重构.结果表明,MCMC方法计算速度快,适用范围广泛,重构效果好.最后将MCMC方法扩展到三维空间,重构出三维多孔介质模型,为微观渗流机理的研究提供了一个模拟平台.     

Simulated annealing reconstruction and characterization of a LiCoO2 Lithium-ion battery cathode

We reconstruct the three-dimensional microstructure of a cathode from a commercial LiCoO2 Lithium-ion battery with an adapted simulated annealing approach. The real size distribution curve of LiCoO2 particles is applied to regulate the reconstruction process. By discretizing a 40 μm×40 μm×40 μm cathode volume with 8000000 numerical cubes, the cathode involving three individual phases： （1） LiCoO2 as active material, （2） pores or electrolyte, and （3） additives （polyvinylidene fluoride＋carbon black） is reconstructed. Characterization of the reconstructed cathode gives important structural and transport properties including volume-specific surface area between phases, tortuosity and geometrical connectivity of individual phase.     

基于二维图像和多点统计方法的多孔介质三维重构研究

提出了一种基于多孔介质二维薄片图像和多点统计方法的多孔介质三维重构方法.将微米精度的多孔介质二维薄片图像作为初始的训练图像,利用多点统计方法重构其下层图像.将每次获得的下层图像作为新的训练图像,利用多点统计方法继续重构该训练图像的下层图像.二维重构图像的每个像素对应成三维空间的一个体素,依次叠加每层的二维重构图像得到最终的三维多孔介质图像.将该方法应用于砂岩样品的三维重构,通过与真实情况下砂岩体数据的比较发现,该方法重构的多孔介质具有与其相似的孔隙结构特征.     

基于各向异性扩散滤波的仿组织材料超声扫描数据三维重建

针对仿组织材料超声扫描数据,给出了一种基于各向异性扩散滤波的三维重建方法。该方法先对超声扫描数据进行二维成像,然后应用各向异性扩散滤波方法根据图像的内容采取不同的平滑策略对二维图像进行滤波处理,可以提取质量较好的轮廓。运用此方法对仿组织材料的超声数据进行处理,并采用等值面绘制的方法完成仿组织材料的三维重建和三维显示,实验结果表明各向异性扩散滤波在超声扫描数据三维重建中具有较好的效果。     

Crack spacing of unsaturated soils in the critical state

The cracking mechanism of unsaturated soils due to evaporation is poorly understood, and the magnitude of crack spacing is usually hard to estimate. In this work, cracks were postulated to occur succedently rather than simultaneously, that is, secondary cracks appear after primary cracks as evaporation continues. Formulae of the secondary crack spacing and secondary trend crack spacing were then derived after stress analysis. The calculated spacing values were consistent with the published experimental data. Meanwhile, the effect of the Poisson ratio on the crack spacing was analyzed, which showed that the magnitude of crack spacing was proportional to the Poisson ratio in the range of [0.30, 0.35].     

Millennial temperature reconstruction based on tree-ring widths of Qilian juniper from Wulan, Qinghai Province, China

The climate of the past 1000 years is an important context for evaluating the recent climate warming. However, there are few 1000-year-long climate reconstructions with annual resolution in the Qinghal-Tibet Plateau. In this paper, a dendroclimatic analysis was conducted for the radial growth of Qilian juniper from the upper forest limit in Wulan, Qinghai Province. The results of correlation analysis between the tree-ring widths and the climate variables indicate that the growth of junipers at the upper forest limit is mainly limited by low temperatures of September, November and February of the pregrowth season, and July of the current growth season. There is no significant correlation between the tree-ring widths and precipitation. A mean temperature from the previous year＇s September to the current year＇s April was reconstructed for the Wulan area since A.D. 1000. The reconstruction can explain 40.8% of the instrumental variance in the calibration period （1856-2002）. The reconstruction shows that the 20th century is the warmest 100 years, and the 1990s is the warmest decade during the past 1000 years, while the coldest 100 years and decade occur at 1600-1699 and 1642-1651, respectively. The variations are verified well by the temperature reconstruction of the middle Qilian Mountain （QL） and the total organic carbon （TOC） in the Qinghai Lake sediments. The comparison of our reconstruction with the annual temperature reconstruction of extra-tropical Northern Hemisphere suggests that the climate of Wulan during the Medieval Warm Period is of obvious regional specialty, but there was a good response to the climate of hemispheric scales during the recent 400 years.     

基于生成对抗网络的页岩三维数字岩芯构建

页岩油气藏孔隙结构复杂,岩芯获取困难,准确表征页岩储层孔隙结构是研究页岩储层内流体渗流规律的关键。基于真实页岩岩芯的三维聚焦离子束扫描图像,对原始生成对抗网络模型的结构重新设计,同时,为了保证重建结果可以充分反映页岩岩芯的孔隙结构信息,增大了训练样本的尺寸,以此训练生成模型,进而生成页岩三维数字岩芯,对比分析了重建数字岩芯和原始岩芯的孔隙度,并基于重建数字岩芯提取了孔隙网络模型,分析了页岩孔隙结构性质。结果显示,重建岩芯的孔隙度、孔隙空间结构、连通性以及孔隙喉道的配位关系与原始岩芯具有很高的一致性,由此验证了生成模型可以实现三维页岩数字岩芯的构建。最后,构建了多个页岩数字岩芯,计算了多个孔隙结构参数的均值及变化区间,证明了生成的数字岩芯具有稳定的孔隙空间特征,训练好的生成模型具有良好的稳定性。     

Development of a middle and low latitude theoretical ionospheric model and an observation system data assimilation experiment

On the basis of previous work, we develop a middle and low latitude theoretical ionospheric model in this paper, named Theoretical Ionospheric Model of the Earth in the Institute of Geology and Geophysics, Chinese Academy of Sciences （TIME-IGGCAS）. TIME-IGGCAS solves the equations of mass continuity, motion and energy of electron and ions self-consistently and uses an eccentric dipole field approximation to the Earth＇s magnetic field. We combine the Eulerian and Lagrangian approaches in the model and take account of the plasma ExB drift velocity. Calculation results reveal that the model is steady and credible and can reproduce most large-scale features of ionosphere. By using TIME-IGGCAS, we carried out an observation system data assimilation experiment. Assimilation results show that the ExB drift velocity can be accurately estimated by ingesting the observed foF2 and hmF2 into the model applying nonlinear least-square fit method. We suggest that this work is of great significance in the development of ionospheric data assimilation model to give better nowcast and forecast of ionosphere.     

QSAR analysis of substituted benzylamino- and heterocyclylmethylamino-carbodithioate derivatives of 4-（3H）-quinazolinone using CoMFA and SCORE2.0

Thymidylate synthase (TS) is a critical enzyme for DNA biosynthesis and many nonclassical lipophilic antifolates targeting this enzyme are quite efficient and encouraging as antitumor drugs. In this paper, the binding model of 14 antifolates of substituted benzylamino- and heterocyclylmethylamino- carbodithioate derivatives of 4-(3H)-quinazolinone with TS is examined using molecular simulation methods―― FlexiDock and SCORE2.0. The resulting conformation and orientation of these antifolates are directly applied to CoMFA study. The robust QSAR model, its three-dimensional contour map, and binding score of these antifolates derived from SCORE2.0 provide guidelines for structural optimiza- tion of current antifolates. The experiment indicates that deletion of cancer chemopreventive structure of dithiocarbamate is unfavorable for interaction between TS and antifolates.     

A method for haplotype inference in general pedigrees without recombination

The abundance of single nucleotide polymorphisms (SNPs) makes the haplotype-based method instead of single-maker-oriented method the main approach to association studies on QTL mapping. The key problem in haploptype-based method is how to reconstruct haplotypes from genotype data. Directly assaying haplotypes in diploid individuals by experimental methods is too expensive, therefore the in silico haplotyping-determination methods are the major choice at the present. This paper presents a rapid and reliable algorithm for haplotype reconstruction for tightly linked SNPs in general pedigrees. It is based on six rules and consists of three steps. First, the parental origins of alleles in offspring are assigned conditional on genotypes in parent-offspring trios; second, the redundant haplotypes are eliminated based on the six rules; and finally, the most likely haplotype combinations are chosen via maximum likelihood method. Our method was verified and compared with PEDPHASE by simulated data with different pedigree sizes, numbers of loci, and proportions of missing genotypes. The result shows that our algorithm was superior to PEDPHASE in terms of computing time and accuracy of haplotype estimation. The computing time for 100 runs was 10―15 times less and the accuracy was 4%―10% higher than PEDPHASE. The result also indicates that our method was very robust and was hardly affected by pedigree size, number of loci, and proportion of missing genotypes.     

Engineering <Emphasis Type="Italic">Deinococcus radiodurans</Emphasis> into biosensor to monitor radioactivity and genotoxicity in environment

Based on a genetically modified radioresistant bacteria Deinococcus radiodurans, we constructed a real time whole cell biosensor to monitor radioactivity and genotoxicity in highly radioactive environment. The enhanced green fluorescence protein （eGFP） was fused to the promoter of the crucial DNA damage-inducible recA gene from D. radiodurans, and the consequent DNA fragment （PrecA-egfp） carried by plasmid was introduced into D. radiodurans R1 strain to obtain the biosensor strain DRG300. This engineered strain can express eGFP protein and generate fluorescence in induction of the recA gene promoter. Based on the correlation between fluorescence intensity and protein expression level in live D. radiodurans cells, we discovered that the fluorescence induction of strain DRG300 responds in a remarkable dose-dependent manner when treated with DNA damage sources such as gamma radiation and mitomycin C. It is encouraging to find the widely detective range and high sensitivity of this reconstructed strain comparing with other whole cell biosensors in former reports. These results suggest that the strain DRG300 is a potential whole cell biosensor to construct a detective system to monitor the biological hazards of radioactive and toxic pollutants in environment in real time.     

Reconstructing mean maximum temperature of growing season from the maximum density of the Schrenk Spruce in Yili, Xinjiang, China

To study the historical temperature variation in Yili of Xinjiang, the tree-ring chronologies of maximum density （MXD） and tree-ring width （TRW） were established with the Schrenk Spruce （Picea schrenkiana Fisch. et Mey） collected from six sites to analyze the characteristics and ability of response to climate change. The results suggest that the MXD chronology of the Schrenk Spruce from different sampling sites responded to climate change well and were positively correlated with the mean maximum temperature and the mean temperature from April to August in the study area. The mean maximum temperature anomaly from April to August, spanning the years from 1848 to 2000, was reconstructed by three MXD chronologies which were selected by stepwise regression. The reconstructed function was stable and explained 56.2% of the variance. The reconstructed results indicated a cold span of 153 years in spring and summer from the beginning of the 1950s to the beginning of the 1970s in the Yili valley. No strongly increasing tendency was detected in the mean maximum temperature anomaly from April to August during this reconstructed period.     

改进的软硬阈值法及其在地震数据降噪中的研究

采集的野外地震数据伴随有随机噪声干扰,需要将其消除。软硬阈值法能够压制地震数据的噪声信号,但是降噪效果并不理想。因此,提出了一种改进的软硬阈值算法用于地震数据降噪。首先利用软硬阈值法原理构建了一种新的阈值降噪法,并对新算法相关特性进行了研究,通过仿真实验确定了新阈值算法的小波基为sym 3,利用均方差和信噪比对新阈值降噪法的降噪效果进行了评价。最后,将新阈值降噪法用于实际地震数据降噪,结果发现新阈值降噪法能够去除地震数据中的随机噪声,降噪效果较软硬阈值法更理想。     

具有生物降解功能的生物陶瓷材料研究

研究、制备了组元和结构类似于人体硬组织的多孔生物活性陶瓷材料HA-TCP[Ca_(10)(PO_4)_6(OH)_2-Ca_3(PO_4)_2]。在完成了生物实验和动物种植实验之后,该多孔生物活性材料在临床外科上得到了应用。X光显示表明,在短时间内植入的该材料能降解成硬组织、能在手术空洞中形成新骨小梁。文章较详细地介绍了HA-TCP粉末及材料的制备过程和适宜于软组织生长的孔隙结构和临床应用效果。     

自适应直接取样岩心三维重建算法

由于直接取样算法在重建过程中引入了多个需要手动调节的参数,使其在实际运用中具有一定的难度.针对这一问题,提出了一种自适应直接取样岩心三维重建算法.首先,使用三级网格对图像进行逐级重建;其次,使用高斯加权来提高模式匹配的准确性;然后,根据待匹配数据事件的条件数据点自适应的选择模式搜索范围,将距离最小模式的中心点赋给待模拟点;最后,使用算法与传统直接取样算法分别对多张储集层岩心图像进行三维重建.通过比较重建结果与真实结构在统计分布、孔隙结构上的差异,证明了算法的有效性.     

Statistic characteristics of severe convective storm during Warm-Season in the Beijing-Tianjin region and its vicinity

This study analyzed the climatological characteristics of severe convective storms in the Beijing and Tianjin region and its vicinity based on the Doppler radar data of Tanggu during May-August of 2003-2007. The climatological characteristics, e.g. storm area, volume, top height, max reflectivity, life time and motion, are analyzed. The results include： 75% of all storms in the Beijing-Tianjin region last no more than 30 minutes, and most storms have a volume less than 400 kin3; most storms move from southwest to northeast while the speed is between 10-30 km/h; the mean storm top height is about 6 km, but some strong convective storms can have a top height larger than 15 kin; finally, storm area and volume have a similar geographical distribution character showing increasing trends from west to east. Compared with the statistic results based on the conventional surface meteorological observations, the results based on the radar data can present not only 3D spatial statistic results of convective storms （e.g., volume and top height）, but also the quantitative climatological characteristics, such as the lifetime and speed distributions. These statistical results are useful for studying the climatic characteristics of convective storms in the Beijing-Tianjin region and its vicinity.     

基于国标的地学数据库智能建模方法

为方便地学数据库设计，缩短建库周期，避免建成的数据库结构不能更改以及使建成的数据库能更好地为地学信息共享服务，提出了地学数据库的智能建模方法．该建模方法采用国家标准分类术语代码辅助设计技术和数据字典技术来辅助数据库设计，对数据模型进行标准化设计，并在设计过程中提供了相关的术语代码字典以支持数据库的标准化数据采集，促进了地学信息共享，同时提供了相应的数据库模型字典，为后期的数据库结构的变动提供支持．     

North China sub-craton lithospheric structure elucidated through coal mine blasting

We present a super-range seismic observation along the >1300-km-long profile passing through the Yinchuan basin and the Ordos block from the blasting point towards the southeast triggered by a large-(dynamite) scale coal blast in the Ningxia Hui Autonomous Region’s Helan Mountain (yielded a profile). The seismic wave information from the uppermost mantle reflecting different depths was obtained by the China continental seismic survey. Pn refracted waves from the uppermost mantle were effectively traced up t...