FOREARC MANTLE METASOMATISM BY 11B-DEPLETED FLUIDS FROM A HIGHLY DEHYDRATED SLAB: A SNAPSHOT OF SLAB ROLL-BACK?

Accretionary orogens form along convergent plate margins due to the ongoing subduction of oceanic lithosphere, and comprise accretionary prisms, magmatic arcs, back-arc domains, ophiolitic mélanges and possibly oceanic plateaus and continental fragments [Condie, 2007; Cawood et al., 2009]. Based on the dips and velocities of subducting slabs, accretionary orogens can be divided into retreating and advancing type, as exemplified by modern SW Pacific and Andes, respectively [Royden, 1993; Cawood et al., 2009].Accretionary orogens form along convergent plate margins due to the ongoing subduction of oceanic lithosphere, and comprise accretionary prisms, magmatic arcs, back-arc domains, ophiolitic mélanges and possibly oceanic plateaus and continental fragments [Condie, 2007; Cawood et al., 2009]. Based on the dips and velocities of subducting slabs, accretionary orogens can be divided into retreating and advancing type, as exemplified by modern SW Pacific and Andes, respectively [Royden, 1993; Cawood et al., 2009]

Effect of antiferromagnetic coupling at interfaces on magnetic properties of Gd/CoFeTaB multilayers

In this work, a multilayer structure composed of Gd and CoFeTaB was prepared by magnetron sputtering, and the effect of annealing temperatures on magnetic properties of the multilayer structure are investigated. The existence of interfacial antiferromagnetic coupling in this system was proved by analysis of microstructure, magnetic characteristics, and magnetic resonance characteristics. The preparation of artificial multilayer antiferromagnetic structure with weak stray fields was demonstrated, which provides a shortcut for spintronics application

Keratin/Polyvinyl Alcohol Blend Films Cross-Linked by Dialdehyde Starch and Their Potential Application for Drug Release

Feather keratin (FK) extracted from feathers represents a valuable source of biodegradable and biocompatible polymer. The aim of this study was the development and characterization of blended films based on FK and polyvinyl alcohol (PVA) cross-linked by dialdehyde starch (DAS) for a potential drug release application. The compatibility of FK/PVA was improved when cross-linked by DAS: the relative crystallinity of the PVA/FK film slightly decreased, and the enthalpy value for the melting peak decreased by about 50% for the cross-linked films. The total soluble mass of all blend films in water was below 35% at 37 °C, indicating a good stability of the films in water. The results of the Rhodamine B dye (as a model drug) release tests showed that the release rates decreased with increasing DAS content. DAS-induced cross-linking improves several important properties of the FK/PVA films, such as the compactness, the compatibility, and the stability in water. These improvements offer the potential to expand the application of FK films in the biomaterial field

GEODYNAMICS OF THE KAZAKHSTAN OROCLINE, CENTRAL ASIA

Curved mountain belts, commonly referred as to oroclines that result from bending of quasi-linear orogenic belts, have fascinated generations of geologists. Such structures are widely recognized in modern and ancient orogens, and are fundamentally important for understanding geodynamics of convergent plate boundaries. However, how and why orogenic belts become bent has been in debate. Here we investigate the Kazakhstan Orocline in the Central Asian Orogenic Belt with an aim at understanding the geodynamics of oroclinal bending in accretionary orogens.Curved mountain belts, commonly referred as to oroclines that result from bending of quasi-linear orogenic belts, have fascinated generations of geologists. Such structures are widely recognized in modern and ancient orogens, and are fundamentally important for understanding geodynamics of convergent plate boundaries. However, how and why orogenic belts become bent has been in debate. Here we investigate the Kazakhstan Orocline in the Central Asian Orogenic Belt with an aim at understanding the geodynamics of oroclinal bending in accretionary orogens

Online preparation of high-quality BN coatings with atomic diffusion based on carbon-free water-soluble precursor

Efficient and environmentally friendly production of high-quality continuous fiber coatings using current preparation methods is highly challenging due to issues such as scale and batch processing restrictions, low deposition rate, high energy consumption, and utilization of multiple environmentally hazardous steps. To address these challenges, we propose a stable and efficient wet chemical deposition coating method for high-throughput online continuous preparation of boron nitride (BN) coatings on ceramic fibers under an ambient environment. Our process involves surface modification, in-situ wet chemical deposition, and heat treatment, and all seamlessly connecting with the ceramic fiber preparation process through continuous stretching. Hydrophilic groups were introduced via surface modification enhancing wettability of the fiber surface with impregnating solution. An in-situ reaction and atom migration improve uniformity and binding of the coating. As a result, outstanding impregnation and adhesion properties are achieved. A comprehensive analysis to evaluate the impact of the BN coatings was conducted, which demonstrates that the BN-coated fibers exhibit a remarkable 36% increase in tensile strength, a 133% increase in fracture toughness, and enhanced temperature resistance of up to 1600 ℃. It provides a secure and efficient platform for cost-effective production of functional and high-quality coatings through targeted surface modification and rapid stretching impregnation

Synthesis of the polymerizable room temperature ionic liquid AMPS – TEA and superabsorbency for organic liquids of its copolymeric gels with acrylamide

A polymerizable room temperature ionic liquid (RTIL), 2-acrylamido-2-methyl-1-propane sulfonic acid (AMPS) – triethylamine (TEA), was synthesized by neutralization of AMPS with TEA in acetone followed by evaporation of the solvent under a reduced pressure at room temperature. The RTIL was characterized with fourier transform infrared spectroscopy, differential scanning calorimetry (DSC), and 1H NMR. Co-polymeric gels of the RTIL with acrylamide (AAm) were prepared by aqueous solution polymerization using N,N′-methylenebisacrylamide as a crosslinker, and ammonium persulfate as an initiator. Superabsorbency of the gels in aqueous and a series of organic liquids was investigated gravimetrically. DSC data showed that the glass transition temperature of AMPS – TEA was 59.4 °C. Poly (AMPS – TEA-co-AAm) gels exhibited superabsorbency in both water and a series of organic solvents. The mechanism for swelling in aqueous and organic media of the gels was critically discussed

A method to achieve spectral beam combining based on a novel symmetric grating

A symmetric grating is proposed to obtain higher output power in spectral beam combination by increasing the number of lasers and spectral utilization. The grating allows laser beams to be incident from both sides of the grating normal to achieve coaxial beam combining, so the number of beams and the combined output power are doubled compared with the traditional grating under the same spectral line-width. The grating is designed with the central wavelength of 4.65 μm, and the calculation results show that this grating is very advantageous for spectral beam combining, especially for the light waves in the range 4.55–4.71 μm, where their diffraction efficiencies are high (over 80%) and correspond to a wide and linear range of incidence angles. Meanwhile, based on the symmetric gratings we further propose a circular grating to achieve the same frequency spectral beam combining. This beam combining design will not increase the laser spectral line width while enhancing the laser power, reducing the requirements for the unit laser spectral line width, which is very meaningful in some application fields and will further enrich the research of spectral beam combining

Structural characteristics of Jan Mayen microcontinent and tectonic evolution model of volcanic passive margin in distal domain

With the deepening of global oil and gas exploration research, the North Atlantic polar region has gradually become the frontier of oil and gas exploration, but the exploration degree of Jan Mayan micro-continent is very low.The study on stratigraphy, structures and tectonic evolution modelling of the Jan Mayan microcontinent (JMMC)is presented in the paper based on seismic, gravity and magnetic data newly acquired by CNOOC in its contract area and other new published papers which show the most update progress of the JMMC. Located in the central part of the Norwegian-Greenland Sea of the North Atlantic, the JMMC is conjugate with the Jameson Land Basin on the Greenland continent margin and the Vøring Basin on the Norwegian shelf margin of the Beltic Continent in accordance with similar Paleozoic-Mesozoic stratigraphy. The JMMC extends southwards from the Jan Mayan fracture zone towards northern Iceland and its architecture shows the characteristics of detachment faults which is similar to the Mesozoic fault system of the Vøring Basin. The distribution of SDR, volcanic intrusion and explosion can be interpreted on the seismic data which indicates the JMMC is the distal domain of the volcanic passive margin in the North Atlantic mostly during the Cenozoic age. The tectonic evolution model is setup by analogic basin analysis and is supposed to start from the Paleozoic-Mesozoic orogeny to rifting, and then be influenced by the twice seafloor spreading of the age 55 Ma and 25 Ma. The first seafloor spreading of 55 Ma age caused the continental crust break-up and formed the volcanic passive margin between the Greenland and Beltic, especially the JMMC's separating from the conjugate Norwegian shelf margin. The second seafloor spreading of 25 Ma age caused the oceanic ridge jump due to the Iceland mantle plume drifting off the Greenland and also caused the JMMC's separation from the Greenland Continent as an 'abandoned orphan' floating on the oceanic crust. The meaning of this study is to discuss kinematic evolution of residual continental crust detached from the distal domain of the plate and to indicate lithospheric extension and break while the embryonic oceanic crust generating through the detachment movements and mantle upwelling

Fabrication of porous SiC(y) (core)/C (shell) fibres using a hybrid precursor of polycarbosilane and pitch

Porous SiCy (core)/C (shell) composite fibres have been fabricated using a simple KOH controlled-activation of SiCx fibres, which were pyrolyzed from polycarbosilane-pitch blend fibres. Effects of activation conditions and pyrolysis temperatures were studied. There are distinctive interfaces observed on the cross-sections of the co-axial fibres, where Si content varies gradually from the core to the shell. The etching of Si follows a slow “core-reducing” process in N2, while in CO2, cracks are frequently observed on the shells due to the accelerated activations. V-shaped Si-free carbon fibres could be obtained when a lower pyrolysis temperature was used to produce the SiCx fibres.Microporous carbon (MC)-based materials have received intensive attention in the context of physisorption for hydrogen storage in the coming era of hydrogen economy [1]. Recently, tremendous efforts have been made to prepare MCs with high specific surface areas (SSAs) and developed porosity, typically, high SSAs can be achieved by controlled-activation of carbon precursors [3], template-assembling using Zeolites [2], or metal-extracting from carbides (carbide-derived carbons, CDCs) [4]. All these candidates have shown brilliant future for the hydrogen storage. However, the amounts of hydrogen adsorbed are still quite limited under high pressure and ambient temperature conditions [5]. Fortunately, the modification of C surfaces through incorporation of functional groups or dopants facilitates increasing binding energy of hydrogen with MCs and most recently, B-substituted MC has been synthesized and exhibited increased H2 storage capacity, 3.2 wt.%, almost double that of MC with similar SSA [6]. As simulated [7], Si should be a good alternative dopant due to the much higher binding energy of hydrogen with SiC. However, SiC usually has low SSA and hard to fabricate porous structure. We here reported a simple one-step activation to produce porous SiC fibres using a hybrid precursor of polycarbosilane (PCS) and pitch. Interestingly, novel core–shell structured materials were obtained. The influences of processing parameters on the cross-section morphologies were discussed in this letter.Polycarbosilane and pitch were mixed with a weight ratio of 55%/45%, melt-spun into green fibres, cured in air and pyrolyzed in N2 giving C-rich SiCx fibres. Then the SiCx fibres were loaded with KOH at a definite impregnation mass ratio (R = wt. KOH/wt. fibres), and activated in N2 or CO2 at a defined temperature/duration (for experimental details, see Supplementary information).<br/

LA-ICP-MS zircon and monazite U-Pb data for the key lithological units in the Chonghuer-Jiadengyu region of the Chinese Altai

Identification of advancing and retreating modes in fossil orogenic belts is not always straightforward. Such issue is addressed in the submitted paper via the case study of the northwestern Chinese Altai where the suprasubduction structures are well preserved. Combined with detailed mapping, structural/petrological observations, seven samples were collected from the key lithological units of Jiadengyu and Chonghuer region in the Xinjiang Uygur Autonomous Region for zircon and monazite U-Pb dating to provide critical geochronological constraints on the individual deformational episodes, including two zircon samples (19CA36 and 17CA105-7) and five monazite samples (17CA107, 17CA105-4, 19CA41, 19CA45-1, and 19CA45-3). Migmatite samples 19CA41 and 17CA107 are characterized by sub-horizontal S1 foliations associated with extensional shear bands. Sample 19CA45-1 collected from the migmatitic Habahe Group domain shows nearly complete transposition of S1 foliation by S2 fabric. Samples 19CA36 and 19CA105-7 were collected from syn-D2 granite intrusions. Leucogranite dyke (sample 17CA105-4) and pegmatite (sample 19CA45-3) were emplaced as tensional fractures that formed in response to D2 shortening. Zircon and monazite grains were separated after rock crushing using conventional heavy liquid and magnetic properties and then selected under a binocular microscope. These grains were mounted in epoxy resin, polished to approximately one-third of their thickness. U-Pb dating of zircon and monazite were analyzed by LA-ICP-MS at the Wuhan SampleSolution Analytical Technology Co., Ltd. U-Pb dating of zircon samples were conducted by a COMPexPro 102 ArF excimer laser and a MicroLas optical system coupled with an Agilent 7700e ICP-MS. Most analyses were performed with a beam diameter and frequency of 32 μm and 5 Hz. GJ-1 standard zircon was also determined for monitoring the accuracy of U-Pb dating. Zircon 91500 was used as an external standard for U-Pb dating calibration. U-Pb dating of monazite samples was performed using the same operating processes and instruments. In this work, the spot size and frequency of the laser were set to 16 μm and 2 Hz, respectively. Monazite standard 44069 was used as an external standard for U-Pb dating. Monazite standard Trebilcock was used as a secondary standard to assess the accuracy of analyses. Each analysis of zircon/monazite was performed using a background acquisition of approximately 25 s followed by 65 s of data acquisition