RC-circuit-like dynamic characteristic of the magnetic domain wall in ferromagnetic nanowires

We have investigated dynamic behaviors of the magnetic domain wall under perpendicular magnetic field pulses in ferromagnetic nanowires using micromagnetic simulations. It has been found that the perpendicular magnetic field pulse can trigger the magnetic domain wall motion, where all the field torques are kept to be on the plane of nanowire strip. The magnetic domain wall speed faster than several hundreds meters per second is predicted without the Walker breakdown for the perpendicular magnetic driving field stronger than $200~\mathrm{mT}$. Interestingly, the dynamic behavior of the moving magnetic domain wall driven by perpendicular magnetic field pulses is explained by charging- and discharging-like behaviors of an electrical RC-circuit model, where the charging and the discharging of "magnetic charges" on the nanowire planes are considered. The concept of the RC-model-like dynamic characteristic of the magnetic domain wall might be promising for spintronic functional device applications based on the magnetic domain wall motion.Comment: 16 pages, 4 figure

A regioselectivity switch in Pd-catalyzed hydroallylation of alkynes.

By exploiting the reactivity of a vinyl-Pd species, we control the regioselectivity in hydroallylation of alkynes under Pd-hydride catalysis. A monophosphine ligand and carboxylic acid combination promotes 1,5-dienes through a pathway involving isomerization of alkynes to allenes. In contrast, a bisphosphine ligand and copper cocatalyst favor 1,4-dienes via a mechanism that involves transmetalation. Our study highlights how to access different isomers by diverting a common organometallic intermediate

Shoshonitic enclaves in the high Sr/Y Nyemo pluton, southern Tibet: Implications for Oligocene magma mixing and the onset of extension of the southern Lhasa terrane

Post-collisional potassic and high Sr/Y magmatism in the Lhasa terrane provides critical constraints on the timing and mechanism of subduction of Indian lithosphere and its role in the uplift of the Tibetan Plateau. Here, we report whole-rock geochemistry, mineral geochemistry, zircon U Pb ages, and in situ zircon Hf isotope ratios for the Nyemo pluton, a representative example of such magmatism. The Nyemo pluton is composed of high Sr/Y host rocks and coeval shoshonitic mafic microgranular enclaves (MMEs). Whole-rock compositions of the host rocks and MMEs form linear trends in Harker diagrams, consistent with modification of both end-members by magma mixing. Although the main high Sr/Y phase of the pluton formed by partial melting of the lower crust of the thickened Lhasa terrane, the MMEs display abnormally enriched light rare earth elements, low whole-rock ε_(Nd)(t) and low zircon ε_(Hf)(t) that suggest derivation from low degree melting of hydrous and enriched mantle. Based on the occurrence of shoshonitic magma and high La/Yb and high Sr/Y with adakitic affinity host rocks around 30 Ma, the Nyemo pluton is best explained as a record of onset of extension that resulted from convective removal of the mantle lithosphere beneath Tibet in the Oligocene

Phenomenological Scaling of Rapidity Dependence for Anisotropic Flows in 25 MeV/nucleon Ca + Ca by Quantum Molecular Dynamics Model

Anisotropic flows ($v_1$, $v_2$, $v_3$ and $v_4$) of light fragments up till the mass number 4 as a function of rapidity have been studied for 25 MeV/nucleon $^{40}$Ca + $^{40}$Ca at large impact parameters by Quantum Molecular Dynamics model. A phenomenological scaling behavior of rapidity dependent flow parameters $v_n$ (n = 1, 2, 3 and 4) has been found as a function of mass number plus a constant term, which may arise from the interplay of collective and random motions. In addition, $v_4/{v_2}^2$ keeps almost independent of rapidity and remains a rough constant of 1/2 for all light fragments.Comment: 4 pages, 5 figure

An Autonomous Observation and Control System Based on EPICS and RTS2 for Antarctic Telescopes

For an unattended telescopes in Antarctic, the remote operation, autonomous observation and control are essential. An EPICS (Experimental Physics and Industrial Control System) and RTS2(Remote Telescope System, 2nd Version) based autonomous observation and control system with remoted operation is introduced in this paper. EPICS is a set of Open Source software tools, libraries and applications developed collaboratively and used worldwide to create distributed soft real-time control systems for scientific instruments while RTS2 is an open source environment for control of a fully autonomous observatory. Using the advantage of EPICS and RTS2 respectively, a combined integrated software framework for autonomous observation and control is established that use RTS2 to fulfill the function of astronomical observation and use EPICS to fulfill the device control of telescope. A command and status interface for EPICS and RTS2 is designed to make the EPICS IOC (Input/Output Controller) components integrate to RTS2 directly. For the specification and requirement of control system of telescope in Antarctic, core components named Executor and Auto-focus for autonomous observation is designed and implemented with remote operation user interface based on Browser-Server mode. The whole system including the telescope is tested in Lijiang Observatory in Yunnan Province for practical observation to complete the autonomous observation and control, including telescope control, camera control, dome control, weather information acquisition with the local and remote operation.Comment: 20 pages,15 figure

Differentiated rare-element mineralization in an ongonite − topazite composite dike at the Xianghualing tin district, Southern China: an electron-microprobe study on the evolution from niobium-tantalum-oxides to cassiterite

International audienceOur study characterizes in detail the mineralogical, textural and compositional features of a highly evolved, composite ongonite-topazite dike and its magmatic differentiation history. We present compositional data collected by established techniques, i.e. by electron microprobe and wet-chemical analysis, which provide a detailed framework for future studies that employ state-of-the-art analytical techniques. The studied dike (referred to as the No. 431 dike) crops out within the Xianghualing area in the Nanling Range of southern China, in close spatial association with Jurassic Sn-Nb-Ta granite plutons. The rock samples in the No. 431 dike were collected from a structurally lower drill hole and a trench at higher level. The ongonite is encountered throughout the dike, but the topazite is only revealed along the margin of the upper, near-surface dike. The results of whole-rock major and trace element analyses show that the rocks of the No. 431 dike are strongly peraluminous with an average ACNK value of ~ 1.5 for ongonite and > 3.9 for topazite. They are enriched in F, 1.7 wt.% and 5.4 wt.% on average for ongonite and topazite, respectively. The rocks have low Zr/Hf and Nb/Ta ratios, and high levels of ore-forming elements including Nb, Ta, Sn, and W. Silicate and oxide mineral assemblages, textures, and compositions are also distinct for the two rock types studied. In the lower ongonite of the dike, there are abundant phenocrysts of K-feldspar, quartz, and albite, and microphenocrysts of topaz and zinnwaldite in a matrix dominated by quartz, K-feldspar, and albite. Characteristic oxides are columbite-tantalite, tapiolite, and microlite, but cassiterite is absent. The upper ongonite of the dike has a silicate assemblage similar to the lower ongonite; columbite-(Mn), uranomicrolite, and limited amounts of cassiterite are the dominant accessory minerals. The topazite is characterized by large amounts of topaz and zinnwaldite intergrown with quartz, while K-feldspar, albite, and quartz phenocrysts have rounded shapes and are relatively rare. Cassiterite is the most abundant ore mineral, while Nb-Ta oxide minerals are less abundant. We interpret the whole-rock compositional trends, mineral textures, assemblages, and compositions to reflect the differentiation of an evolved, initially homogeneous magma that separated into aluminosilicate and hydrosaline melts, corresponding to crystallization of ongonite and topazite, respectively. The crystallization of Nb-Ta- and Sn-bearing ore minerals was strongly controlled by the separation of the two melt phases. We hypothesize that dike propagation/widening subsequent to the initial dike emplacement may have driven the separation of the aluminosilicate and hydrosaline melt phases that crystallized to ongonite in the core and topazite along the margins of the structurally higher part of the dike

Median effective effect-site concentration of sufentanil for wake-up test in adolescents undergoing surgery: a randomized trial

BACKGROUND: To determine the median effective concentration of sufentanil as an analgesic during wake-up tests after sevoflurane anesthesia during surgery for adolescent idiopathic scoliosis (AIS). METHODS: This is a randomised controlled trial. Sixty patients aged 13–18 years scheduled for AIS surgery were randomized into six groups of 10 patients each to receive target effect-site concentrations of sufentanil of 0.19, 0.1809, 0.1723, 0.1641, 0.1563, and 0.1489 ng/ml (target concentration ratio, 1.05). Wake-up time was recorded. Median EC(50) and 95% confidence interval (CI) for sufentanil target-controlled infusion (TCI) were determined using Kärber’s method. The primary outcome was median EC(50) for sufentanil TCI as an analgesic during the wake-up test after sevoflurane anesthesia during surgery for AIS. RESULTS: The EC(50) and 95% CI of sufentanil TCI were 0.1682 ng/ml and 0.1641 ~ 0.1724 ng/ml, respectively. CONCLUSIONS: The EC(50) of sufentanil TCI was 0.1682 ng/ml (95% CI: 0.1641 ~ 0.1724 ng/ml) during sevoflurane anesthesia in adolescents undergoing surgery for idiopathic scoliosis with intraoperative wake-up tests. TRIAL REGISTRATION: Clinicaltrials.gov identifier: ChiCTR-TTRCC-12002696

Eocene magmatic processes and crustal thickening in southern Tibet : insights from strongly fractionated ca. 43 Ma granites in the western Gangdese Batholith

This research was financially co-supported by the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (XDB03010301), the National Key Project for Basic Research of China (Project 2015CB452604), the Chinese National Natural Science Foundation (41225006, 41472061, and 40973026), the MOST Special Fund from the State Key Laboratory of Geological Processes and Mineral Resources (China University of Geosciences). The first author thanks the China Scholarship Council (201306400021).This study reports zircon U-Pb age and Hf isotope, whole-rock major and trace element, and Sr-Nd-Pb-Hf isotope data for the Dajia pluton, western Gangdese Batholith, in southern Tibet. These data indicate that the pluton consists of moderately (Group 1) and strongly (Group 2) fractionated granites that were emplaced synchronously at ca. 43 Ma. The Group 1 samples have SiO2 contents of 69−72 wt.% and vary in terms of the differentiation index (DI = 84−93). These rocks are depleted in Ba, Nb, Sr, P, and Ti, with moderate negative Eu anomalies, and display low heavy rare earth elements (HREEs) and Y abundances. The Group 2 samples are characterized by high SiO2 (75−78 wt.%) and DI (95−97); significantly negative Eu anomalies; marked concave-upward middle REE (Gd-Ho) patterns; and Ba, Sr, P, and Ti anomalies that are significantly more negative than those of the Group 1 samples. The Group 1 samples have whole-rock εNd(t) (-5.9 to -6.0), εHf(t) (-4.0 to -4.5), and zircon εHf(t) (-6.0 to + 5.8) values identical to those of the Group 2 samples [εNd(t) = -5.7 to -6.7, εHf(t) = -3.5 to -2.9, and zircon εHf(t) = -2.0 to + 4.2], as well as similar initial Pb isotopic compositions. These data indicate that the two groups were derived from a common source region with garnet as a residual mineral phase. The Group 1 samples were most likely derived from partial melting of garnet-bearing amphibolite (rather than eclogite) within the juvenile southern Lhasa crust and mixed with the enriched components from the subducting ancient Indian continental crust and/or the ancient central Lhasa basement. The Group 2 samples are interpreted as the products of extensive fractional crystallization (plagioclase, K-feldspar, biotite, apatite, allanite, titanite, monazite, and ilmenite) of the melts represented by the Group 1 samples. Low HREEs and Y abundances of the Dajia pluton, together with the presence of strongly fractionated granites (Group 2) identified for the first time in the Gangdese Batholith, indicate that the crust beneath the Dajia region had already been thickened by ca. 43 Ma. High whole-rock zircon saturation temperatures (815°C−869°C) of the Group 1 samples and the other ca. 43 Ma coeval magmatism documented both in the Gangdese Batholith and in the Tethyan Himalaya can be best interpreted as the final consequences of the magmatic responses to the Neo-Tethyan oceanic slab breakoff.PostprintPeer reviewe