Derivation of P–T paths for Middle–Late Triassic very low-grade metapelite from Hongcan Well 1 in the Zoigê Depression and their tectonic implications

Using XRD measurements of illite crystallinity,b0values of K-rich white micas and chemical compositions of chlorites combined with homogenization temperatures of fluid inclusions in calcite,the metamorphic P–T conditions of very low-grade metapelites from different depths in the 7 km Hongcan Well 1 in the Zoige?Depression,Sichuan,China,have been obtained in this paper.Knowledge of the tectonic evolution of the studied basin allows us to derive geothermal curves for Middle and Late Triassic time(the geothermal peak)and the present day(from thermal logging of the borehole).The retrograde P–T tracks from clockwise P–T–t loops have been revealed by the plotting of individual samples on each geotherm,which can be interpreted by the lithospheric thickening due to sedimentation and folding followed by continuous uplift and erosion.A stratigraphic log indicates that the Well penetrates the steep limb of a fold which perturbed the peak geotherm and caused some P–T paths to cross.     

Crystallization behavior of Fe78Si13B9 metallic glass under high magnetic field

The effects of high magnetic field on the crystallization behavior of the Fe₇₈Si₁₃B₉ metallic glass ribbon were studied. The samples were isothermal annealed for 30 min under high magnetic field and no field,respectively. Microstructure transformation during crystallization was identified by X-ray diffraction and transmission electron microscopy. It was found that the crystallizations of Fe₇₈Si₁₃B₉ metallic glass processed under different conditions were that the precipitation of dendrite α-Fe(Si) and spherulite (Fe,Si)₃B phases forms amorphous matrix and then the metastable (Fe,Si)₃B phase transforms into the stable Fe₂B phase. The grain size of the crystals is smaller and more homogeneous for the isothermal annealed samples under high magnetic field in comparison with that under no field indicating that the crystallization behavior of Fe₇₈Si₁₃B₉ metallic glass is suppressed by high magnetic field.     

Modified HDDR Process for Producing Anisotropic NdFeB Powders

The effect of HDDR (hydrogenation-decomposition-desorption-recombination process) treating conditions on magnetic anisotropy of Nd₁₃Fe_balCo₁₇B₇Ga₁Zr_0.1 powders has been studied. It is found that increasing recombination temperature is effective for magnetic anisotropy formation, but at the cost of reducing the coercive force. The microstructure analysis (TEM) indicates that the NdFeB recombination nucleation takes place markedly during the transition range from decomposition stage to recombination stage, in which both temperature and H₂ pressure change sharply. In order to create a more stable treatment condition for recombination nucleation, a modified HDDR process is established in which the conventional continuous transition range is divided into several stages. The experimental results have proved that such a process can effectively enhance the remanence of the magnet powders with high certainty, while only cause a little reduction in coercivity.     

Preparation and High Temperature Oxidation Properties of Micro-crystalline MGH754 ODS Alloy Coatings

A special coating technique, electro-spark deposition (ESD), was developed to produce micro-crystalline ODS MGH754 alloy coatings on a commercial 1Cr18Ni9Ti stainless steel and a cast Ni20Cr alloy substrates. The coatings have a very fine grain structure and metallurgical bonding with the substrates. The isothermal oxidation tests at 1000 ℃ in air showed that the micro-crystalline ODS alloy coatings had a much reduced oxidation rate and improved scale spallation resistance compared with the uncoated alloys. The selective oxidation of Cr was greatly promoted to form protective and continuous Cr₂O₃ scales on the alloy surface. Micro-crystallization and oxide dispersions have synergistic effects on the improvement of oxidation resistance. The beneficial effects were discussed based on the experimental results.     

Genome-wide association study identifies eight new risk loci for polycystic ovary syndrome

Following a previous genome-wide association study (GWAS 1) including 744 cases and 895 controls, we analyzed genome-wide association data from a new cohort of Han Chinese (GWAS 2) with 1,510 polycystic ovary syndrome (PCOS) cases and 2,016 controls. We followed up significantly associated signals identified in the combined results of GWAS 1 and 2 in a total of 8,226 cases and 7,578 controls. In addition to confirming the three loci we previously reported, we identify eight new PCOS association signals at P < 5 × 10(-8): 9q22.32, 11q22.1, 12q13.2, 12q14.3, 16q12.1, 19p13.3, 20q13.2 and a second independent signal at 2p16.3 (the FSHR gene). These PCOS association signals show evidence of enrichment for candidate genes related to insulin signaling, sexual hormone function and type 2 diabetes (T2D). Other candidate genes were related to calcium signaling and endocytosis. Our findings provide new insight and direction for discovering the biological mechanisms of PCOS.     

Innate partnership of HLA-B and KIR3DL1 subtypes against HIV-1

Allotypes of the natural killer (NK) cell receptor KIR3DL1 vary in both NK cell expression patterns and inhibitory capacity upon binding to their ligands, HLA-B Bw4 molecules, present on target cells. Using a sample size of over 1,500 human immunodeficiency virus (HIV)+ individuals, we show that various distinct allelic combinations of the KIR3DL1 and HLA-B loci significantly and strongly influence both AIDS progression and plasma HIV RNA abundance in a consistent manner. These genetic data correlate very well with previously defined functional differences that distinguish KIR3DL1 allotypes. The various epistatic effects observed here for common, distinct KIR3DL1 and HLA-B Bw4 combinations are unprecedented with regard to any pair of genetic loci in human disease, and indicate that NK cells may have a critical role in the natural history of HIV infection.     

Meta-analysis identifies 13 new loci associated with waist-hip ratio and reveals sexual dimorphism in the genetic basis of fat distribution

Waist-hip ratio (WHR) is a measure of body fat distribution and a predictor of metabolic consequences independent of overall adiposity. WHR is heritable, but few genetic variants influencing this trait have been identified. We conducted a meta-analysis of 32 genome-wide association studies for WHR adjusted for body mass index (comprising up to 77,167 participants), following up 16 loci in an additional 29 studies (comprising up to 113,636 subjects). We identified 13 new loci in or near RSPO3, VEGFA, TBX15-WARS2, NFE2L3, GRB14, DNM3-PIGC, ITPR2-SSPN, LY86, HOXC13, ADAMTS9, ZNRF3-KREMEN1, NISCH-STAB1 and CPEB4 (P = 1.9 × 10?? to P = 1.8 × 10???) and the known signal at LYPLAL1. Seven of these loci exhibited marked sexual dimorphism, all with a stronger effect on WHR in women than men (P for sex difference = 1.9 × 10?3 to P = 1.2 × 10?13). These findings provide evidence for multiple loci that modulate body fat distribution independent of overall adiposity and reveal strong gene-by-sex interactions.     

Differentiability of Functions on Spheres and Criterions of Convexity

Some basic concepts for functions defined on subsets of the unit sphere, such as the s-directional derivative, s-gradient and s-Gateaux and s-Frechet differentiability etc, are introduced and investigated. These concepts are different from the usual ones for functions defined on subsets of Euclidean spaces, however, the results obtained here are very similar. Then, as applications, we provide some criterions of s-convexity for functions defined on unit spheres which are improvements or refinemen...     

Carbothermic reduction of vanadium titanomagnetite with the assistance of sodium carbonate

The carbothermic reduction of vanadium titanomagnetite concentrate (VTC) with the assistance of Na₂CO₃ was conducted in an argon atmosphere between 1073 and 1473 K.X-ray diffraction and scanning electron microscopy were used to investigate the phase transformations during the reaction.By investigating the reaction between VTC and Na₂CO₃,it was concluded that molten Na₂CO₃ broke the structure of titanomagnetite by combining with th...     

机器视觉

本书全面介绍了机器视觉，提供了所有必须的理论工具，说明了这些理论工具怎样在实际的图像处理与机器视觉系统中的应用，特点是包括了许多计算机练习（这些练习对透彻理解实用图像处理算法很有帮助）。作者从对数学原理的复习开始，然后讨论了图像处理中的关键问题，例如图像的描述与表征、边缘检测、特征抽取、分段、纹理与形状等。本书注重应用，两个再现的主题是一致性（这是解决机器视觉问题主要的基本原理结构）和优化（用于实现这些方法的数学工具）。