狮泉河-纳木错混杂带的构造属性和演化时限一直存在较大的争议,其研究对认识青藏高原早期形成与演化具有重要的意义.对西藏中仓蛇绿混杂岩中发育的玄武岩端元进行了系统的岩石学、地质年代学和地球化学研究,以揭示其形成时代、岩石成因及构造意义.中仓玄武岩LA-ICP-MS锆石U-Pb同位素年龄为115.7±2.0 Ma,与区域上辉长岩的形成时代一致.玄武岩整体具有相对平坦的球粒陨石标准化稀土元素配分曲线,与洋中脊玄武岩相似,且显示Th的富集和Nb、Ta的亏损.研究认为,中仓玄武岩起源于受俯冲沉积物改造的尖晶石橄榄岩地幔部分熔融,形成于弧后扩张脊环境.结合区域上同时期辉长岩的研究结果,认为狮泉河-纳木错混杂带是中生代弧后洋盆消亡的残迹,是班公湖-怒江洋南向俯冲,引发弧后拉张的产物.

The network embedding method can map the network nodes to a low-dimensional vector space and ext-ract the feature information of each node effectively. In the field of service recommendation, some studies show that the introduction of network embedding method can effectively alleviate the problem of data sparsity in the recom-mendation process. However, the existing network embedding methods are mostly aimed at a specific structure of the network, and do not cooperate with a variety of relationship networks from the source. Therefore, this paper proposes a service recommendation method based on multi-network hybrid embedding (MNHER), which maps mul-tiple relational networks to the same vector space from vertical and parallel perspectives. Firstly, the social network of users, the shared network of service tags and the user-service heterogeneous information network are constructed. Then, the hybrid embedding method proposed in this paper is used to obtain the embedding vector of users and services in the same vector space. Finally, the service recommendation is made to target users based on the embed-ding vector of users and services. In this paper, the random walk method is further optimized to extract and retain the characteristic information of the original network more effectively. In order to verify the effectiveness of the method proposed in this paper, it is compared with a variety of representative service recommendation methods on three public datasets, and the F-measure values of the service recommendation methods based on single relational network and simply fused multi-relational network are improved by 21% and 15%, respectively. It is proven that the method of multi-network hybrid embedding can effectively coordinate multi-relationship network and improve the quality of service recommendation.

灵湖金矿床位于华北克拉通南缘的小秦岭地区,矿体大多呈脉状产于断裂带内.成矿过程可初步划分为石英-黄铁矿、石英-多金属硫化物和石英-碳酸盐-黄铁矿3个阶段.Au主要沉淀于石英-多金属硫化物阶段.成矿期石英中发育富液两相、富气两相和H2 O-CO2三相包裹体.石英-黄铁矿阶段发育富液两相包裹体,其完全均一温度为424℃～499℃,盐度为11.5％～13.6％NaCleq,密度为0.55～0.66 g·cm-3;石英-多金属硫化物阶段发育富气两相、富液两相和H2O-CO2三相包裹体,其完全均一温度为291℃～389℃,盐度为0.4％～11.8％NaCleq,密度为0.50～0.83 g·cm-3;石英-碳酸盐-黄铁矿阶段可见富液两相和富气两相包裹体,其完全均一温度为206℃～289℃,盐度为8.3％～22.2％NaCleq,密度为0.83～0.99 g·cm-3.成矿流体具有高温、中低盐度和低密度等特征.灵湖金矿床中石英的δ18 OH2O值为0.7‰～4.5‰,δD值为-106.4‰～-86.1‰.H-O同位素分析结果表明,成矿流体主要来源于岩浆水.矿石硫化物的δ34S值为-8.5‰～2.4‰,206Pb/204Pb值为17.202～17.796,207Pb/204Pb值为15.448～15.473,208Pb/204Pb值为37.712～38.255.S-Pb同位素分析结果表明,成矿物质主要来源于低级下地壳部分熔融形成的花岗质岩浆.灵湖金矿床为岩浆热液型金矿,流体相分离和温度的降低是导致矿质沉淀的主要机制.

高轻质、耐高温合金有着广泛的应用前景.在本文中,将纯Ti箔和SiCp/Al复合箔在660℃下退火,利用SEM对不同退火时间的样品进行观察分析,研究了Ti(Al,Si)3的抛物线生长动力学.XRD结果表明,SiC颗粒的引入及其Si元素的固溶改变了TiAl3的晶格稳定性.

Acyl fluorides have moderate electrophilicity and a very good balance between stability and reactivity. Utilization of acyl fluorides as versatile building blocks in transition-metal catalysis attracts fast-growing and great attention recently. Development of rapid and operationally simple synthetic methods for acyl fluorides has always been desirable. We report herein a rapid, simple and efficient acyl fluoride synthesis from carboxylic acids with Cu(O2CCF2SO2F)(2) as a deoxofluorination reagent. Notably, Cu(O2CCF2SO2F)(2) was readily prepared in large scale from inexpensive starting material, and previously used as a good tri-fluoromethylating reagent. (C) 2020 Elsevier Ltd. All rights reserved.

通过对科右前旗一带梅勒图组火山岩LA-ICP-MS锆石U-Pb定年和元素地球化学分析,获得梅勒图组安山质晶屑熔结凝灰岩及安山岩的喷发年龄分别为125.6±1.6Ma和120.2±2.2Ma,指示梅勒图组火山岩的形成时代介于120～126Ma之间,形成于早白垩世中期.岩石具有高的SiO2(60.4％～65.3％)和全碱(7.0％～9.5％)含量,铝饱和指数A/CNK为0.89～0.98,属于钾玄岩及高钾钙碱性系列;稀土元素总量为124×10-6～169×10-6,(La/Yb)N值为5.83～13.4,负Eu异常微弱(δEu=0.84～1.05);在原始地幔标准化微量元素蛛网图上,样品富集Rb、Ba、Th、U、K、La、Nd,亏损Nb、Ta、P和Ti,Sr/Y值介于19.4～29.7之间.其岩石源区为富集地幔,岩浆上升过程中受到地壳物质的混染,岩石形成于板内伸展环境,其地球动力学背景可能与古太平洋板块的俯冲有关.

在服务推荐过程中,为了把社交关系对用户兴趣的影响标签化,提升推荐结果的准确性,提出一种基于利用可靠用户补充标签的服务推荐方法SRST,通过在相似用户之间构建可靠用户网络,比较可靠用户网络中每个用户节点的度数得到度数最大的Top-k2个可靠用户,并通过这些可靠用户的兴趣标签对目标用户的标签进行补充,再利用补充后的标签集进行服务推荐,最后在公开数据集Delicious上进行实证分析.

对密排六方结构的钛材而言,孪生是一种重要的塑性变形机制.在加工过程中产生的各类孪晶不仅可使微观组织和织构发生显著改变,还会对其力学性能产生重要影响.重点从纯钛板材轧制过程中可能产生的孪晶类型、影响孪生变形的因素、孪晶对钛板组织、织构及各向异性的影响等方面对国内外近年的相关研究进行了综合评述,并对今后的研究工作进行了展望.

Practical, mild, and efficient. Broad scope and good functional group tolerance.

Presented is a novel intermolecular radical trifluoromethylfluorosulfonylation of unactivated alkenes under mild reaction conditions with good functional-group tolerance in the most atom-economic manner by using readily available Ag(O2CCF2SO2F) and N-fluorobenzenesulfonimide (NFSI). Both the trifluoromethyl and sulfonyl groups in the products originate from Ag(O2CCF2SO2F).

A general route to transform metal oxide semiconductors from non-SERS active to SERS-active substrates based on defect engineering is reported. The SERS enhancement factor (EF) of metal oxide semiconductors like α-MoO3 and V2O5 can be greatly enhanced and the SERS performance can be optimized according to the detecting analyte and activating laser wavelength by introducing oxygen vacancy defects. The EF of R6G on α-MoO3-x nanobelts can be as high as 1.8 × 107 with a detection limit of 10-8 M, which is the best among metal oxide semiconductors and comparable to noble metals without a "hot spot". A model, named "effective electric current model", was proposed to describe the photo-induced charge transfer process between the absorbed molecules and semiconductor substrates. The EF of 4-MBA, R6G and MB on α-MoO3-x nanobelts with different oxygen vacancy concentrations calculated based on the model matches very well with experimental results. As an extension, some potential metal oxide semiconductor SERS-active substrates were predicted based on the model. Our results clearly demonstrate that, through defect engineering, the metal oxide semiconductors can be made SERS-active substrates with high stability and high biocompatibility.

A seed-mediated electrochemical method was used to grow Ag nanoplates with controllable size. The sodium citrate tribasic dihydrate was used as the capping agent to control the growth of Ag seeds, and L-ascorbic acid was employed as the reducing agent in electrolyzing growth of Ag nanoplates. Ag nanoplates with size ranging from 250 nm to 2.2 mu m and thickness in several tens of nanometer have been realized. The influence of input electric current, seeds content and reaction time on the size and size uniform of Ag nanoplates were discussed and analyzed. Our method can primly control the kinetic growth process of Ag nanoplates and slow down the reaction rate, and can be easily scaled for mass production. (C) 2017 The Electrochemical Society. All rights reserved.

An active and dynamic infrared switching film device was built via integrating VO2 (M) nanoparticles and the ITO glass substrate. The infrared optical transmittance of the device can be real-time manipulated by an applied voltage, overcoming the high Tc limit of VO2 (M) and providing a new insight into the applications of transparent conductive electrodes in the thermochromic field.

A new trifluoromethylating reagent Cu(O2CCF2SO2F)(2), which easily decomposes to generate active CuCF3 species in DMF at room temperature, has been conveniently prepared from inexpensive starting materials on a large scale. This new reagent can be applied to efficiently trifluoromethylate a variety of haloarenes under mild conditions, providing good-to-excellent yields of the desired products.

High power diode lasers are widely used for pumping of solid state lasers and fiber lasers, material processing, medical treatment, sensors, free-space optical communication, security and defense.However, the conventional diode lasers usually suffer from a large far-field divergence and strongly elliptical beam, which limit the direct applications.To improve the divergence, diode lasers based on Bragg reflection waveguide(BRW) are studied in this project, which utilizes the photonic bandgap(PBG) effect rather than the total internal reflection( TIR) to provide optical confinement.Several kinds of BRW lasers( BRLs) with different structures are designed and fabricated.First, the mode dispersion equation of the BRW is solved by the transfer matrix method and Bloch theory.The further analysis shows that the far-field distribution of BRW is determined by the mode shape in the cavity.In the case of Bragg form of PBG guidance, the optical field characteristics of a quarter-wave BRL and a single-sided BRL are studied.The essential reason affecting the far-field distribution is investigated.Finally, a twin-beam laser based on BRW is designed and demonstrated. Almost all the emission power of this laser is concentrated in two near-circular lobes in the vertical direction. The full-width at half maximum(FWHM) divergence angles of one beam are as narrow as 7.2°and 5.4°re-spectively in the vertical and lateral direction.Furthermore, the high brightness BRL with a ultra-narrow cir-cular output beam is demonstrated by controlling the defect layer.The ultra-low vertical divergence of 9.8° with 95%power content and 4.9°with the FWHM definition is realized.The maximum output power exceeds 4.6 W under continuous-wave operation at room temperature.The narrow circular beam emission from the BRL can greatly improve the pumping efficiency and optical fiber coupling efficiency without expensive beam shaping.It is believed that the BRLs have a promising application prospect.

从凉红-苏雄剖面开建桥组底部沉凝灰岩中获得了801.3 Ma±7.2 Ma锆石SHRIMP U-Pb年龄,与前人获得的苏雄组803 Ma±12 Ma年龄高度一致,不仅有效地约束了开建桥组的沉积时代,还从地质年代学上进一步证实了两者之间的同时异相关系,为华南新元古界地层格架的建立提供了新的年龄证据.结合前人研究成果,本文认为开建桥组的沉积时限为800 Ma～725 Ma,与康滇地区澄江组、扬子东南缘莲沱组和上墅组可以对比.同位素年代学、岩石地球化学及沉积学等研究表明,800 Ma左右是整个华南地区裂谷盆地沉积充填序列第二个旋回的开启时间.

A practical and efficient method for the direct trifluoromethylthiolation of unactivated C(sp(3) )H bonds by AgSCF3 /K2 S2 O8 under mild conditions is described. The reaction has a good functional-group tolerance and good selectivity. Initial mechanistic investigations indicate that the reaction may involve a radical process in which K2 S2 O8 plays key roles in both the activation of the C(sp(3) )H bond and the oxidation of AgSCF3 .

Vanadium pentoxide nanorods assemblies were synthesized by a microwave-assisted hydrothermal synthesis, combined with subsequently annealing treatment. The structure and morphology of the nanorods were characterized by XRD, FESEM and HRTEM, and the electrochemical properties of the electrodes made from the V2O5 nanorods were investigated. The V2O5 nanorods with an average diameter of 100 nm and lengths up to several micrometers are almost parallel distributed in the assemblies. The V2O5 nanorods assemblies exhibit an initial discharge capacity of 330 mA hg(-1) at a current density of 50 mA g(-1), which is very higher than that of the separated V2O5 nanorods. The V2O5 nanorods assemblies also show a lower capacity fading rate in comparison with the separated V2O5 nanorods. A low polarization of the charge transfer reaction and a high diffusion rate of lithium ion inside the electrode composed of the paralleled nanorods are considered responsible for the enhanced capacity. (C) 2015 Elsevier Ltd. All rights reserved.

As a result of the subduction, the Cretaceous magmatic rocks must record the information of the process and therefore provide the opportunity for understanding the evolution of the Bangong Co-Nujiang River Ocean basins and boundary conditions for models of the origin and evolution of the Tibetan Plateau. This paper reports two zircon U-Pb ages of Qushenla Formation volcanic rocks and also new whole-rock major and trace element data of the newly discovered basalt unit. LA-ICP-MS dating of zircons from two rhyolitic samples yielded ages of 104.14Ma and 104.95Ma, which indicate that the Qushenla volcanic rocks in the study area were formed in late Early Cretaceous. The basalts are depleted in Nb, Ta, and Ti, and characterized by high Zr abundances and high Zr/Y and (Th/Nb)N ratios, which suggests that they were generated by partial melting of hot asthenospere with contributions from the crust. The new data obtained by the authors, together with recently published data of rhyolites, have led the authors to believe that the generation of the bimodal volcanic suite in an extensional setting resulted from the slab break-off of the southward subduction of the Bangong Co-Nujiang River Ocean lithosphere.