High Field Strength Research Articles

Recent Advanced Ultra‐Wide Bandgap β‐Ga2O3 Material and Device Technologies

AbstractGallium oxide (Ga2O3) is an emerging ultra‐wide bandgap (UWBG) semiconductor material that has gained significant attention in the field of high voltage and high frequency power electronics. Its noteworthy attributes include a large bandgap (Eg) of 4.8 eV, high theoretical critical breakdown field strength (EC) of 8 MV cm−1, and saturation velocity (νs) of 2 × 107 cm s−1, as well as high Baliga figures of merit (BFOM) of 3000. In addition, Ga2O3 has the advantages of large‐size substrates that can be achieved by low‐cost melt‐grown techniques. This review provides a partial overview of pivotal milestones and recent advancements in the Ga2O3 material growth and device performance. It begins with a discussion of the fundamental material properties of Ga2O3, followed by a description of substrate growth and epitaxial techniques for Ga2O3. Subsequently, the contact technologies between Ga2O3 and other materials are fully elucidated. Moreover, this article also culminates with a detailed analysis of Ga2O3‐based high voltage and high frequency power devices. Some challenges and solutions, such as the lack of p‐type doping, low thermal conductivity, and low mobility are also presented and investigated in this review.

Numerical simulation of electric field-induced phase transition evolution and boiling characteristics in the evaporative cooling medium C6F12O

Phase change cooling technology offers high cooling efficiency, safety, and reliability, representing a novel approach to achieving efficient heat dissipation for high-power and large-capacity electrical equipment. The formulation of the cooling medium is pivotal to phase change cooling technology. However, current media exhibit compatibility, stability, economy, and environmental friendliness deficiencies. Consideration could be given to implementing the C6F12O medium due to its superior overall performance and ability to meet the latent heat requirements in phase change cooling equipment. This paper employs a numerical simulation approach that combines the phase field method based on the Cahn-Hilliard equation with the theory of electrohydrodynamics. It investigates the impact of temperature, electric field intensity, and electric field direction on the evolution of bubble motion and the boiling state of the C6F12O medium, considering the interaction of electric-fluid-heat-phase fields. Numerical results indicate that the system undergoes initial nucleate boiling, nucleate boiling, and film boiling stages at T = 330–335 K, T = 335–350 K, and T ⩾ 355 K, respectively. The introduction of an appropriate electric field can enhance the motion evolution of C6F12O bubbles. However, attention must be paid to the formation of bubble channels under high field strength to prevent potential decreases in insulation performance. An inhomogeneous electric field in the vertical direction proves more effective in improving the bubble release rate compared to a uniform electric field. To some extent, an inhomogeneous electric field in the horizontal direction can prevent the mass accumulation of bubbles in regions of high field intensity. This research has the potential to offer theoretical guidance for the engineering application of the C6F12O phase change cooling medium.

The Optimization of Microwave Field Characteristics for ODMR Measurement of Nitrogen-Vacancy Centers in Diamond

A typical solid-state quantum sensor can be developed based on negatively charged nitrogen-vacancy (NV−) centers in diamond. The electron spin state of NV− can be controlled and read at room temperature. Through optical detection magnetic resonance (ODMR) technology, temperature measurement can be achieved at the nanoscale. The key to ODMR technology is to apply microwave resonance to manipulate the electron spin state of the NV−. Therefore, the microwave field characteristics formed near the NV− have a crucial impact on the sensitivity of ODMR measurement. This article mainly focuses on the temperature situation in cellular applications and simulates the influence of structural parameters of double open loop resonant (DOLR) microwave antennas and broadband large-area (BLA) microwave antennas on the microwave field’s resonance frequency, quality factor Q, magnetic field strength, uniformity, etc. The parameters are optimized to have sufficient bandwidth, high signal-to-noise ratio, low power loss, and high magnetic field strength in the temperature range of 36 °C to 42.5 °C. Finally, the ODMR spectra are used for effect comparison, and the signal-to-noise ratio and Q values of the ODMR spectra are compared when using different antennas. We have provided an optimization method for the design of microwave antennas and it is concluded that the DOLR microwave antenna is more suitable for living cell temperature measurement in the future.

Numerical demonstration of an efficient up-conversion enhancement strategy by plasmon excitations in a gap-mode nanocavity

Lanthanide-doped up-conversion nanoparticles (UCNPs) can be widely used as near-infrared absorbing photoactive materials in bioimaging and photovoltaic devices. However, the low absorption cross section and low luminescence quantum rate of UCNPs significantly limit its use. Therefore, a hexagonal gold pillar nano-array structure consisting of UCNPs, gold pillar arrays, gold film and silica layer is proposed. By optimizing the structural parameters, the surface plasmon resonance wavelengths are simultaneously matched with the 808 nm excitation wavelength and 450 nm emission wavelength of the UCNPs. The gap-mode nanocavity confines the incident excitation radiation to nanophotonic hotspots with greatly high field strengths, thus theoretically proposed an efficient strategy to enhance the up-conversion luminescence. The plasmonic structure investigated in this study combines the advantages of ease of processing, high absorption, low loss and good controllability of its localized surface plasmon resonance. It provides a new solution for up-conversion enhancement design of gap-mode nanocavities.

Eocene mafic alkaline volcanism in north Central Iran; Signatures of development and subsequent melting of a pyroxenite mantle source

Volcanic rocks from the Miami-Davarzan area are basalts to trachyandesites interlayered with fossiliferous beds and bear significant implications on the Eocene geodynamic evolution of northern central Iran. The rocks constitute two distinct groups, a low-Nb and a high-Nb suite. The least evolved low-Nb suite includes clinopyroxene-olivine phyric samples and is characterized by higher CaO and lower Al2O3 as compared to peridotite partial melts. The high-Nb suite includes more evolved plagioclase-clinopyroxene phyric samples. Fractional crystallization modeling using least-squares mass balance calculations for major elements suggests that the high-Nb suite was formed from a low-Nb parental melt by differentiation of a clinopyroxene-dominated mineral assemblage. The Miami-Davarzan volcanic rocks are characterized by significant large ion lithophile elements (LILE) and light rare earth elements (LREE) enrichment and high field strength elements (HFSE) depletion, which are typical signatures of subduction-related settings. Immobile, highly to moderately incompatible elements such as NbTa, LaCe, PrNd are higher in the Miami-Davarzan volcanic rocks as compared to the typical magmatic arcs, which is an indication of slab melt involvement and metasomatism of the mantle source. The Sr-Nd-Pb isotopic data also confirm a common mantle source involving the addition of subducted sediments into a depleted mantle source for both the low-Nb and high-Nb suites. The geochemical characteristics such as high CaO, low Al2O3, and the isotopic data can be best explained by derivation of the low-Nb suite parental melt from a pyroxenite mantle source. The pyroxenite mantle source was probably developed as a result of interaction between shallow depleted mantle and slab plus sediment-derived melts. It is suggested that the extensional phase that dominated the northern central Iran during the Eocene prompted partial melting of a pyroxenite mantle source.

Structural covariance, topological organization, and volumetric features of amygdala subnuclei in posttraumatic stress disorder

The amygdala is divided into functional subnuclei which have been challenging to investigate due to functional magnetic resonance imaging (MRI) limitations in mapping small neural structures. Hence their role in the neurobiology of posttraumatic stress disorder (PTSD) remains poorly understood. Examination of covariance of structural MRI measures could be an alternate approach to circumvent this issue. T1-weighted anatomical scans from a 3 T scanner from non-trauma-exposed controls (NEC; n = 71, 75 % female) and PTSD participants (n = 67, 69 % female) were parcellated into 105 brain regions. Pearson’s r partial correlations were computed for three and nine bilateral amygdala subnuclei and every other brain region, corrected for age, sex, and total brain volume. Pairwise correlation comparisons were performed to examine subnuclei covariance profiles between-groups. Graph theory was employed to investigate subnuclei network topology. Volumetric measures were compared to investigate structural changes.We found differences between amygdala subnuclei in covariance with the hippocampus for both groups, and additionally with temporal brain regions for the PTSD group. Network topology demonstrated the importance of the right basal nucleus in facilitating network communication only in PTSD. There were no between-group differences for any of the three structural metrics. These findings are in line with previous work that has failed to find structural differences for amygdala subnuclei between PTSD and controls. However, differences between amygdala subnuclei covariance profiles observed in our study highlight the need to investigate amygdala subnuclei functional connectivity in PTSD using higher field strength fMRI for better spatial resolution.

Formation of deep arc root cumulates and implications for crustal growth in the southern Central Asian Orogenic Belt

Formation of ultramafic cumulate rocks at the arc root serves as a key process to understanding the deep evolution of arc magma and crustal growth. However, the arc root cumulates are easy to delaminate due to their high density, making limited field exposure. Here, we conducted comprehensive petrographic observations and geochemical analysis of typical ultramafic rocks (peridotites and pyroxenites) in an ophiolitic complex from the central Beishan orogenic belt in the southern Central Asian Orogenic Belt (CAOB). Petrographic evidence shows that these rocks exhibit characteristic adcumulate and mesocumulate textures with intercumulus minerals such as olivine, orthopyroxene, and clinopyroxene. The mineral characteristics of ultramafic rocks, including olivine and orthopyroxene with lower NiO (0.10–0.33 wt% and 0.03–0.09 wt%, respectively) and Mg# (81–87 and 86–88, respectively), clinopyroxene with higher CaO (19.0–24.7 wt%), and spinel with lower Mg# (0–49), are distinct from those of mantle rocks but resemble cumulates. Both whole-rock and calculated equilibrium melt exhibit the compositions of island arc magma characterized by enrichment in large ion lithophile elements (e.g., Cs, U, Pb, and Sr) and depletion in high field strength elements (e.g., Nb, Ta, Zr, Hf, and Ti). The covariation of high Mg# and low SiO2 in whole rocks is akin to typical arc root cumulates from classic island arcs (e.g., Kohistan and Talkeetna). The positive zircon εHf(t) values (+13 to +16) and calculated crystallization pressure of 0.9–1.1 GPa (~30–40 km) support the formation of ultramafic cumulates in a juvenile island arc setting. These findings imply that most ultramafic rocks in the central Beishan orogenic belt are arc root cumulates instead of the mantle portion of an ophiolitic complex. Fractional crystallization models suggest that arc root cumulate formation may have influenced the evolution of intermediate-felsic rocks in this area, indicating that the differentiation of hydrous arc magma played a crucial role in large-scale crustal growth in the southern CAOB during the Paleozoic.

Improved electrical properties in PZT/PZ thin films by adjusting annealing temperature

In this study, PbZr0.52Ti0.48O3/PbZrO3 (PZT/PZ) multilayer films were prepared on SiO2/Si substrate buffered with LaNiO3 (LNO) thin films, and then annealed at different temperatures by rapid thermal annealing (RTA) technology. The phase structures, microstructures, and electrical properties of the obtained PZT/PZ multilayer films were studied. According to the results of XRD and SEM, it was found that the PZ films with perovskite phase were obtained by annealing at 650 °C firstly. The PZT films on crystallized PZ films were in amorphous phase after annealing at 450 °C, in pyrochlore phase after annealing at 550 °C, and finally in perovskite phase at annealing temperature higher than 600 °C. The multilayer films with the PZT films annealed at 550 °C exhibited linear hysteresis loops, and such films showed the enhanced energy storage density of 31.6 J cm−3 and the energy storage efficiency of 66.9% at a high breakdown field strength of 2475 kV cm−1. The experimental results proved that the phase structure of the PZT/PZ multilayer films can be regulated by different annealing temperatures, which could further enhance the energy storage performance of the PZT/PZ multilayer films.

Petrogenesis of Late Triassic adakitic plutons in the East Kunlun Orogen, Northern Tibet: Geodynamic implications for the Paleo-Tethyan orogeny and crustal evolution

Adakitic rocks found within continental arcs are pivotal in unraveling the geodynamic processes and tectonic evolution of East Kunlun Paleo-Tethyan orogen. We present an integrated study on the petrography, zircon U-Pb geochronology, whole-rock geochemistry, and Sr-Nd-Hf isotopes of newly identified Late Triassic adakitic plutons in the East Kunlun Orogenic Belt (EKOB), Northern Tibet, aiming to constrain their petrogenesis and geodynamic implications. These plutons comprise by mylonitized granite, monzogranite, granodiorite and dioritic porphyrite, exhibiting consistent zircon U-Pb ages of approximately 204–212 Ma. They have high SiO2, K2O and Sr (average of 479 ppm) contents, but low contents of Y (5.6–18 ppm) and Yb (0.5–1.0 ppm) with high Sr/Y ratios (17–63), resembling adakitic rocks. These adakitic rocks can be classified into high-Mg (Mg#= ∼51) and low-Mg groups (Mg#= ∼35), although they all display enriched large ion lithophile elements and light rare earth elements but depleted high field strength elements. The studied low-Mg adakitic rocks have low MgO (∼0.68 wt%) and Cr (∼35 ppm) with enriched zircon Hf isotopes (εHf(t) = − 1.16 t 2.44), suggesting their derivation by partial melting of thickened juvenile crust. Conversely, the high-Mg adakitic rocks exhibit high MgO (∼1.94 wt%) and Cr (∼61 ppm) with relatively high zircon εHf(t) values (−0.68 to 4.95), indicating their derivation from foundered crustal root with subsequent interaction with enriched mantle-derived magma. Tectonic reconstructions suggest that the formation of these Late Triassic adakitic rocks occurred in a post-collisional extension setting and the East Kunlun Paleo-Tethyan Ocean closed no later than Norian.

Comparative analysis of installations for heat treatment of non-food pulp raw materials by the influence of electrophysical factors

Relevance. The objectives of the work are to develop radio-hermetic installations and substantiate the effective design of the working chamber, which provides a comprehensive effect of electrophysical factors on non-food pulp raw materials to preserve feed value at reduced operating costs. Scientific tasks: 1) to develop installations with different designs of resonators; 2) to conduct a comparative analysis of the working chambers according to the main parameters; 3) to evaluate the technical and economic indicators of an effective installation in relation to the basic version.Methods. The effect of electrophysical factors on raw materials is realized in resonators with magnetrons and frequency generators of pulse-modeled high-frequency oscillations of 110 kHz, where a bactericidal flux lamp serves as a high-potential electrode.Results. Several continuous-flow radiohermetic installations with ultrahigh-frequency (microwave) power supply to non-standard resonators have been developed, inside which a complex effect of a high-intensity electric field, a bactericidal flow of UV rays and ozone is realized to reduce bacterial contamination of the product and neutralize odor during heat treatment of raw materials, the dimensions of which are consistent with the depth of penetration of the wave. Features of conical and biconic resonators − provide radio leakage in continuous operation by cutting off the tip at the level of the critical section, depending on the angle of inclination of the cone generator, and allow you to keep the standing wave inside the resonator. The combination of magnetron and cylindrical resonators increases the efficiency of the interaction of the electron flux with the microwave field, and an increase in the inductive volume, which is a “reservoir” of energy, increases the intrinsic quality of the resonator. A quasi-toroidal resonator, presented as a conical resonator in a toroidal resonator, having small overall dimensions and metal consumption, provides a traveling wave in the annular space, and a standing wave in the conical space. The high electric field strength in the capacitor part of the resonator and the corona discharge in the torus contribute to the disinfection of raw materials.

Mantle Sources and Geochemical Evolution of the Picture Gorge Basalt, Columbia River Basalt Group

The Columbia River Basalt Group (CRBG) is the youngest continental flood basalt province, proposed to be sourced from the deep-seated plume that currently resides underneath Yellowstone National Park. If so, the earliest erupted basalts from this province, such as those in the Picture Gorge Basalt (PGB), aid in understanding and modeling plume impingement and the subsequent evolution of basaltic volcanism. Using geochemical and isotopic data, this study explores potential mantle sources and magma evolution of the PGB. Long known geochemical signatures of the PGB include overall large ion lithophile element (LILE) enrichment and relative depletion of high field strength elements (HFSE) typical of other CRBG main-phase units. Basaltic samples of the PGB have 87Sr/86Sr ratios on the low end of the range displayed by other CRBG lavas and mantle-like δ18O values. The relatively strong enrichment of LILE and depletion of HFSE coupled with depleted isotopic signatures suggest a metasomatized upper mantle as the most likely magmatic source for the PGB. Previous geochemical modeling of the PGB utilized the composition of two high-MgO primitive dikes exposed in the northern portion of the Monument Dike swarm as parental melt. However, fractionation of these dike compositions cannot generate the compositional variability illustrated by basaltic lavas and dikes of the PGB. This study identifies a second potential parental PGB composition best represented by basaltic flows in the extended spatial distribution of the PGB. This composition also better reflects the lowest stratigraphic flows identified in the previously mapped extent of the PGB. Age data reveal that PGB lavas erupted first and throughout eruptions of main-phase CRBG units (Steens, Imnaha, Grande Ronde Basalt). Combining geochemical signals with these age data indicates cyclical patterns in the amounts of contributing mantle components. Eruption of PGB material occurred in two pulses, demonstrated by a ~0.4 Ma temporal gap in reported ages, 16.62 to 16.23 Ma. Coupling ages with observed geochemical signals, including relative elemental abundances of LILE, indicates increased influence of a more primitive, potentially plume-like source with time.

Three-Dimensional Transient Electric Field Characteristics of High Pressure Electrode Boilers

An uneven electric field during the operation of an electrode boiler will lead to the emergence of a high field strength area and low field strength area in the furnace, which will endanger the safe and reliable operation and heating efficiency of the electrode boiler. A numerical study of three-dimensional transient electric field distribution characteristics in a 10 kV high-voltage electrode boiler was carried out. The distribution characteristics of the global electric field of the electrode boiler under the nominal voltage of 10 kV were studied, and the distribution law of the electric field of the electrode boiler under poor power quality, such as different bus voltage and three-phase voltage imbalance, was explored. The results show that the electric field distribution characteristics of the three-phase transient are more obvious in the section closer to the electrode disc, and the electric field distribution is the most uniform in the section that is 1.4 m away from the furnace water. In the case of poor power quality, such as different bus voltage and three-phase voltage imbalance, the points of the maximum electric field intensity of the four surfaces change periodically with time, and the greater the bus voltage fluctuation, the more severe the impact on the transient electric field. The three-phase voltage imbalance will shift the peak value of the electric field intensity. The decrease or offset of electric field intensity in the electrode boiler caused by poor power quality will directly affect its heating efficiency. The electric field simulation results have a specific reference value for improving the internal electric field distribution and on-site operation and maintenance of the electrode boiler.

Garnet geochronology, major and trace element geochemistry of the Huanggangliang Fe-Sn polymetallic deposit, NE China

Cu-Fe (Au), W-Sn (Mo), Pb-Zn (Ag) and other element assemblages are common in many skarn deposits, but examples of Fe and Sn coexistence in nature are relatively rare. The Huanggangliang deposit in the southern Great Xing'an Range is the largest Fe-Sn polymetallic deposit in northern China, and there are five main mining areas (SK Ⅰ–SK Ⅴ) distributed along a SW–NE trend. SK Ⅰ and SK Ⅲ are the two larger mining areas in the Huanggangliang deposit, and their mineral assemblages and wall-rocks are significantly different: cassiterite and metal sulfides are duncommon in SK Ⅰ (andesite), while they are widely distributed in SK Ⅲ (marble). Garnet is widely distributed in SK Ⅰ and SK Ⅲ mining areas, and provides a good opportunity to explore the mechanism of Fe-Sn assemblage differentiation. Three types of garnet are distinguishable (Grt 1, Grt 2 and Grt 3) based on their mineral associations, textures and locations, and they mainly belong to the andradite-grossular solid solution series. The LA–ICP–MS U-Pb ages of the garnets from SK Ⅰ and SK Ⅲ are 136.0 ± 1.2 Ma (n = 25, MSWD = 1.9) and 136.2 ± 2.6 Ma (n = 37, MSWD = 1.8), respectively, suggesting that magmatic-hydrothermal activity in these two mining areas began at the same time. Grt 1 (located deep in SK Ⅰ and SK Ⅲ) and Grt 2 (located shallowly in SK Ⅰ) are mainly andradite, while Grt 3 (located shallowly in SK Ⅲ) is mainly grossular. They are all enriched in high field strength elements (HFSEs) and depleted in large ion lithophile elements (LILEs), and their REE patterns are enriched in light rare earth elements (LREEs) and depleted in heavy rare earth elements (HREEs). However, Grt Ⅰ-1a and 1b (deep garnets in SK Ⅰ) exhibit obvious positive Eu anomalies, while the other garnet types exhibit negative or no obvious Eu anomalies. Additionally, Grt 3 has high contents of V, Sn, U, Th, Zn and Y, and low contents of W and Mo. This pattern implies that the garnets in deep SK Ⅰ may have formed under oxidizing conditions with high temperatures, high oxygen fugacity (fO2) and weak acidity, while the garnets in shallow SK Ⅲ formed under reducing conditions with moderate temperatures, moderate fO2 and near-neutral pH. The garnets in shallow SK Ⅰ and deep SK Ⅲ may have formed under weak oxidation–reduction conditions at moderate to high temperatures, moderate fO2 and weakly acidic to neutral pH conditions. Our newly reported field geological, mineralogical, and geochemical data from garnet suggest that the ore-forming fluids of the Huanggangliang were magmatic-hydrothermal fluids mixed with slightly acidic external fluids, chloride complexes may have been the main transport ligands of REEs. The metallogenic environment may be an important factor leading to the difference of mineral assemblages in the Huanggangliang deposit.

Numerical modelling of electromechanical coupling behaviors in HTS coil with implementation of H formulation in FE software

(Re)Ba2Cu3O7-x (REBCO) coated conductors (CCs) have attracted considerable concern because of their outstanding current carrying capacity in magnetic fields of high strengths. A huge electromagnetic force is generated in the superconducting coil when conducting large currents in strong magnetic field. Thus, management of stress and strain has become a key technical challenge for the stability and safety of superconducting coil during operation. To accurately predict the electro-magnetic and mechanical characteristics of superconducting coil in strong magnetic field, an electromechanical model on the basis of the H-formulation and arbitrary Lagrangian-Eulerian (ALE) method is proposed here with FE software. To verify the proposed model, the simulation outcomes of the coil during magnetization are compared with the experimental outcomes. The coupling effect of magnet at high field strengths is dependent on the position of the coil. To reduce the screening current effect, the overshoot method with plateau is found superior to the traditional overshoot method, and an increase in the stabilization time can decrease the maximum value of stress. Finally, the electromechanical behaviors of single winding coil and two-tapes co-winding coil are compared.

Petrogenesis of the Early Cretaceous Tietonggou Diorite and Its Geological Implications

The Tietonggou pluton is mainly composed of gabbroic diorite and diorite. The petrology, zircon U-Pb age, and geochemistry of the Tietonggou diorite have been studied to determine its petrogenesis and metallogenic significance. The diorite samples have 56–58 wt% SiO2 and 11–14 wt% Al2O3 and are peraluminous and sodic (Na2O/K2O = 1.29–2.07). All the samples are enriched in light rare earth elements (LREEs) and large-ion lithophile elements (LILEs; e.g., Rb, Ba, and Sr) but depleted in heavy rare earth elements (HREEs) and high field strength elements (HFSEs; e.g., Zr, Nb, and Ta), suggesting subduction-related affinities. The rocks have narrow ranges of (206Pb/204Pb)t (18.5–19.0), (207Pb/204Pb)t (15.71–15.75), and (208Pb/204Pb)t (38.4–39.0) ratios, respectively. Zircons from the Tietonggou diorite yielded a weighted average U-Pb age of 132.86 ± 0.92 Ma (MSWD = 0.48), whilst those from the nearby Laowa diorite yielded 129.72 ± 0.61 Ma (MSWD = 1.05). This suggests that the rocks represent Early Cretaceous plutons, coeval with the peak lithospheric thinning in eastern North China Craton (NCC). The magma likely originated from partial melting of the enriched lithospheric mantle and was contaminated by ancient lower NCC crustal materials. Our study clarifies the tectonic background of the Tietonggou pluton and provides support for the study of the genesis of Fe–skarn deposits in western Shandong.

An experimental study on the role of F−, PO43−, Cl− and SO42− ligands in the natrocarbonatite-nephelinite system at 850 °C and 0.1 GPa

Carbonatites and their comagmatic silicate rocks related deposit provide significant resources of rare earth elements (REEs), niobium (Nb) and other elements such as U, Th, Mo, V, Ba, Sr, etc. However, the genesis of mineralization, especially for REEs and Nb, in carbonatite remains enigmatic. Previous liquid immiscibility experiments have demonstrated that both REEs and Nb are preferentially enriched in the silicate conjugate instead of carbonate melts under anhydrous conditions. Nevertheless, ligands other than carbonate ion appear to be abundant due to ubiquity of apatite, baryte, celestine, fluorite and sodalite in carbonate–silicate magmatic systems. Here, we experimentally investigate the trace element partitioning between natrocarbonate and silicate (nephelinite) melts in systems doped with varying amounts of additional F−, PO43−, Cl−, and SO42− ligands (0, 2, 4 and 6 wt%) to understand and constrain the role of ligands.The experiments were conducted at 850 °C and 0.1 GPa using rapid quench cold-seal pressure vessels (CSPVs). A comparison of experimental partition coefficients in this study reveals that the significant amounts F− and PO43− incorporated in the silicate melts can increase the D values for REE by influencing melt structure (DLaCM/SM = 0.85–7.42). In contrast, irrespective of the amount of added Cl− and SO42−, DCM/SM is not affected significantly by these species and the DREECM/SM values remain always lower than 1 (DLaCM/SM = 0.12–0.40). Notably, the DNbCM/SM values are all <1, with only one exception containing 6 wt% F. Besides, in all the investigated systems, Ba, Sr, Mo, V, Cs, Rb and Li preferentially partition into the conjugate carbonate melt. All the high field strength elements (Pb, Th, U, Zr, Hf, Nb, Ta), transition metals (Mn, Co, Cu, Zn) and common network formers (Ga, Ge) essentially partition into the silicate melt.

Detrital zircon U–Pb geochronology and geochemistry of sandstones in the Siziwang Banner, Central Inner Mongolia: Implication for tectonic evolution

The central Inner Mongolia, located at the intersection of the northern margin of the North China Craton (NCC) and the Central Asian Orogenic Belt, is crucial for deciphering the Late Palaeozoic tectonic evolution associated with the subduction and closure of the Palaeo‐Asian Ocean (PAO). Our study focused on petrology, detrital zircon LA–ICP–MS U–Pb geochronology and whole‐rock geochemistry for the Late Carboniferous to Permian sandstones within the Shuanmazhuang, Dahongshan, Naobaogou, and Laowopu formations in Siziwang Banner, central Inner Mongolia. This comprehensive analysis shed light on the dynamic interplay between the NCC and the South Mongolia Block. Detrital zircon U–Pb ages in investigated samples mainly cluster between 250 and 2650 Ma, with significant peaks at 2.4–2.5 Ga, 1.8–2.0 Ga, 400–430 Ma, and 250–320 Ma, respectively. The geochemistry data are characterized by SiO2 contents (56.29–77.95 wt. %), Na2O / K2O ratios (0.45–1.58) and SiO2/Al2O3 ratios between 4.33 and 7.44. Moreover, they exhibit the slight enrichment in large ion lithophile elements (Rb and Ba) and the depletion in high field strength elements (Nb, Ta, Th, and U). These facts indicate that the sedimentary detritus predominantly originates from felsic sources, probably deriving from the Late Carboniferous–Permian continental island arc‐related intermediate‐acid igneous rocks, the Late Ordovician‐Silurian magmatic rocks in the Bainaimiao arc and the basements of the NCC. Furthermore, our present results also suggest that during the Early–Middle Permian, accelerating oceanic crust subduction triggered significant magmatic events in Siziwang Banner, leading to rapid uplift and the erosion of arc magmatic rocks, as well as the abundant corresponding sediments. Subsequently, the gradual convergence and eventual collision between the NCC and the Southern Mongolian Block took place at the end of the Permian, representing final closure of the PAO.

Heterogeneity of the late Mesozoic lithospheric mantle beneath the Jiaodong Peninsula, eastern North China Craton: a synthesis from geochemistry and Sr-Nd-Pb isotopes of mafic dykes

ABSTRACT The Late Mesozoic lithospheric mantle evolution of the Jiaodong Peninsula is crucial for understanding the destruction of the eastern North China Craton (NCC) and large-scale gold mineralization, but it still remains highly controversial. Here, we comprehensively compiled published Late Mesozoic mafic dyke magmatism data from the Jiaodong Peninsula to provide key constraints on the nature and evolution of the lithospheric mantle. Mafic dykes are widely emplaced in the Jiaodong Peninsula and have been divided into two groups (Jiaobei terrane and Sulu orogenic belt); they mainly comprise lamprophyre, dolerite, and gabbro. The ages of the mafic dykes in the Jiaobei terrane are predominantly between 120 and 125 Ma, and those of the Sulu orogenic belt are between 110 and 120 Ma. The Jiaobei and Sulu mafic dykes both have high contents of Mg and compatible elements (Cr, Ni), as well as low SiO2 content; they are characterized by arc-like mafic magma, including enrichment in Large Ion Lithophile Elements and Light Rare Earth Elements, depletion in High Field Strength Elements, high (87Sr/86Sr)i, and low εNd(t), implying a metasomatized lithospheric mantle source. However, the Jiaobei mafic dykes have relatively higher (87Sr/86Sr)i, lower εNd(t), and a larger range of (206Pb/204Pb)i, (208Pb/204Pb)i, and (207Pb/204Pb)i compared with the Sulu mafic dykes. The Jiaobei and Sulu mafic dykes exhibit Ba/Rb ratios of 1.29‒64.39 (average 29.3) and 6.61‒108.28 (average 33.1), respectively, indicating the presence of hornblende in the melts. The high Fe/Mn (>60) and Zn/Fe (>12) ratios of Jiaobei and Sulu mafic dykes indicate the mixed mantle source of peridotite and pyroxenite. But the content of pyroxenite in the mantle source of Jiaobei terrane is higher with wider range of Fe/Mn and Zn/Fe ratios. These features indicate the heterogeneity of the mantle sources of the mafic dykes in the Jiaobei and Sulu regions. It is suggested that both regions originated from the partial melting of hornblende-bearing peridotite, with the addition of more pyroxenite to the mantle source of the Jiaobei terrane compared to Sulu orogenic belt. The mafic dykes have the low Nb/Zr (Jiaobei: 0.024–0.229; Sulu: 0.030–0.166) and Th/Zr ratios (Jiaobei: 0.017–0.081; Sulu: 0.010–0.068), and the high Rb/Y (Jiaobei: 0.347–12.162; Sulu: 0.224–9.600) and low Nb/Y ratios (Jiaobei: 0.202–1.486; Sulu: 0.140–1.322). It implies that the mantle source area in both regions was metasomatized by subducted slab-derived fluids. The increase in (La/Yb)N and decrease in Hf/Sm implies carbonate metasomatism in both regions. In addition, some Jiaobei and Sulu mafic dykes have high Ti/Eu ratios, implying that the silicate metasomatism occurred in the mantle source of both regions. Based on the regional evolution, the lithospheric mantle source in the two regions beneath Jiaodong Peninsula experienced carbonated fluid metasomatism resulting from the subduction of the Palaeo-Asian Ocean plate beneath the northern NCC (ca. ~250 Ma), silicate melt-related metasomatism from subduction of the Yangtze Craton plate beneath the southern NCC (ca. 240‒220 Ma), and oceanic slab-derived fluid metasomatism from the subducted Palaeo-Pacific plate (at 180‒110 Ma). It is believed that the mantle source of Jiaobei terrane had undergone stronger carbonated fluid metasomatism and silicate melt-related metasomatism, compared to Sulu orogenic belt. Moreover, the continental fluid-related metasomatism only occurred in the Sulu orogenic belt. During the Late Mesozoic, the eastern NCC experienced large-scale lithospheric thinning, leading to upwelling of the asthenospheric mantle. The mafic dykes in Jiaobei and Sulu, show different geochemical features, were derived from partial melting of the metasomatized lithospheric mantle through upwelling of the asthenospheric mantle.

No observation of DIANA signals in rats at 7.0 and 17.2 Tesla

Abstract Recently, a new method was introduced to detect neuronal activity using MRI. The method, referred to as DIANA, showed MRI signals with millisecond temporal resolution that correlated with local field potentials measured invasively in mice. Troublingly, attempts by other groups to detect the DIANA signals in humans at 7 Tesla and mice at 15.2 Tesla have failed. So far, attempts to reproduce DIANA in small rodents have focused on paradigms using whisker pad stimulation, which were expected to produce a 0.1-0.15% signal change. However, the supplementary material accompanying the original DIANA paper showed that visual stimulation produced a three times larger signal, which should be much easier to detect. Therefore, we attempted to find the DIANA signal in rats using a visual stimulation paradigm. Experiments were performed at 17.2 Tesla but also at 7.0 Tesla to see if the DIANA signal appears at a lower field strength where T2 is longer and BOLD contributions are reduced. In addition, simulations were performed to investigate the theoretical detectability of synthetic DIANA signals in noisy data. Although our data indicated that a 0.1% signal change would have been detectable, we did not observe a DIANA signal. We did observe neuronally driven hemodynamic signal variations that were much larger than the anticipated DIANA signal. The amplitude of these signal changes was relatively similar at 7.0 and 17.2 Tesla (0.7% vs 1.1%). Numerical simulations indicated, however, that the measured hemodynamic signal changes would not interfere with the detection of DIANA signals. Therefore, it is reasonable to expect that measurements at higher field strength with improved SNR would have a better chance to detect the DIANA signal. Yet, we, among others, were unable to find it.

Study on Preparation and Application Technology of Micro scale New Foam Ceramics for Power Equipment

With the proposal of a new type of power system in China, the new environment-friendly insulating medium micro nano foam ceramic is urgently needed to replace SF6, epoxy resin and other insulating materials in the GIS/GIL key power equipment. The new material technology can prepare: foam ceramic design method. Preparation method of foam ceramics and the functional modulation of micro/nano structures. The electrical performance of the foam ceramics was improved. Achievable: the stable performance of micro/nano structures under the high field strength. Excellent thermal conductivity under high current action. It has local replacement function in insulation material applications such as SF6 and epoxy resin. Detectable: Starting from the electrical performance of the UHV hybrid insulation material system, UHF technology and photo-acoustic spectroscopy technology are applied to the high sensitivity detection of the decomposition products and partial discharges of foam ceramics, focusing on types of fluorocarbon decomposition gases, making use of strong correlation between the decomposition products and the partial discharge detection data, and combining the multi-source data fusion algorithm to achieve the prediction of insulation structure data sequence and online detection of the latent faults for the special GIS/GIL.