Search Results (1,320)

The Early Cretaceous post-collisional magmatic evolution of the central Lhasa Terrane remains hotly debated, and the Qula syenogranite provides new constraints on crust–mantle interaction. Whole-rock major and trace element analyses, zircon LA-ICP-MS U–Pb dating, and Sr–Nd–Pb–Hf isotopic analyses were carried out on seven samples from this newly recognized pluton to decipher its petrogenesis and tectonic setting. This pluton exhibits typical geochemical signatures of a weakly peraluminous, ferroan A₂-type granite, including elevated SiO₂ and total alkalis, low Al₂O₃ and CaO contents, high FeO^T/(FeO^T + MgO) (0.86–0.91) and 10,000 × Ga/Al (2.9–3.1), prominent negative Eu anomalies, chondrite-normalized rare earth element patterns with a seagull shape, enrichment in Rb, Th, U, Zr, and Hf, and depletion in Ba, Sr, P, Nb, and Ti. Zircon U–Pb dating yields a weighted mean crystallization age of 105.6 ± 0.46 Ma (MSWD = 1.16, n = 24), corresponding to the late Early Cretaceous. Positive zircon εHf(t) (+4.4 to +5.8), moderately negative whole-rock εNd(t) values (−5.3 to−3.4), and radiogenic Pb isotopic compositions together indicate that the parental magma most likely originated from the partial melting of juvenile lower crust, with contributions from both ancient basement and mantle-derived melts. Slab break-off of the southward-subducted Bangong–Nujiang lithosphere and consequent asthenospheric upwelling following the Qiangtang–Lhasa collision provide the tectonic scenario most consistent with these data, and the magma subsequently underwent extensive fractional crystallization dominated by K-feldspar, plagioclase, and biotite to form the Qula A₂-type syenogranite. Full article

Mafic–intermediate dikes provide useful constraints on mantle source characteristics, crust–mantle interaction, and regional tectono-magmatic evolution. Here we present field, petrographic, whole-rock geochemical, zircon U–Pb–Hf isotopic, and whole-rock Sr–Nd isotopic data for the Haojiang mafic–intermediate dike suite and its host granitoids in eastern Guangdong, SE China. Field observations show that dark, fine-grained dikes sharply intrude light-colored granitoids along fractures or joints. Zircon U–Pb dating of the host granitoid sample HJ-7-3 yields a crystallization age of 137.56 ± 0.76 Ma, whereas the representative dike sample HJ-1 yields a magmatic zircon age of 94.25 ± 0.64 Ma. These ages indicate that at least part of the Haojiang dike suite represents a Late Cretaceous mafic–intermediate magmatic event that postdated Early Cretaceous granitoid emplacement. An older zircon population in HJ-1 yielded an age of 135.8 ± 1.1 Ma and is interpreted as xenocrystic or inherited zircon probably related to interaction with Early Cretaceous granitoid crust or a coeval crustal component during magma ascent. The dike samples have SiO₂ contents of 50.10–58.52 wt.% and plot mainly in the basaltic andesite to andesite fields in the TAS diagram. Major-element variations, compatible trace elements, and weak Eu anomalies are consistent with variable fractional crystallization, although open-system processes cannot be excluded. The dikes are enriched in LILEs and LREEs and depleted in Nb, Ta, and Ti. Their initial ⁸⁷Sr/⁸⁶Sr ratios of 0.705232–0.705772, εNd(t) values of −3.10 to −0.12, and zircon εHf(t) values of −1.61 to +1.30 indicate weakly enriched isotopic compositions. Taken together, these features favor involvement of a subduction-modified enriched mantle source, although contributions from metasomatized lithospheric mantle and enriched asthenospheric mantle cannot be uniquely distinguished. Possible limited crustal interaction during magma ascent is also allowed. The ca. 94 Ma Haojiang dike therefore provides evidence for Late Cretaceous mantle-derived or mantle-influenced magmatism in eastern Guangdong, consistent with a regional extensional regime commonly associated with Paleo-Pacific slab rollback. Full article

Interfacial engineering can modify the electrical response of hafnium zirconium oxide capacitors, but separating polarization dynamics from circuit charging remains essential. We compare approximately 10 nm thick Hf_0.5Zr_0.5O₂ (HZO) capacitors with otherwise identical capacitors containing an additional approximately 1 nm thick ZrO₂ bottom interlayer (hereafter HZO–ZrO₂ capacitors). Polarization–voltage measurements, cross-sectional scanning transmission electron microscopy, capacitance–voltage characterization, and switching/non-switching pulse measurements were combined across electrode areas of 25–10,000 μm². Both stacks exhibit ferroelectric hysteresis and butterfly-shaped capacitance curves. At 2.5 V and 100 kHz, the HZO–ZrO₂ capacitors have 10–15% higher capacitance. Their measured switching-onset delays are nevertheless lower at areas ≥ 400 μm²: 2.1, 5.6, and 23.0 ns at 400, 2500, and 10,000 μm², compared with 3.2, 7.7, and 30.9 ns for HZO; the largest relative reduction is 34.4%, observed at 400 μm², where the delay decreases from 3.2 ns to 2.1 ns. At 25 and 100 μm², the measured differences (0.1 ns) are within the ≈0.1 ns timing resolution of the single-record measurement and are reported as descriptive values. Dividing the measured delay by the capacitance yields a quantity with resistance units that serves as a useful diagnostic for comparing devices, but it cannot be equated with a physical contact resistance. In particular, simply setting the delay equal to R × C with the nominal 100 Ω external resistance leads to an inconsistency for the largest HZO–ZrO₂ capacitors, where it would imply a negative additional resistance. These results associate ZrO₂ insertion with reduced operational delay while establishing the calibration requirements for interpreting its physical origin. Full article

Cement-board composites were prepared at a fixed nominal filler loading to compare the attenuation response of different high-Z additives under a common mass-fraction condition. A commercial cement board was used as the host matrix, and five formulations containing 30 wt% Bi₂O₃, BaSO₄, HfO₂, WO₃, or Fe were fabricated and compared with a pure pressed control. X-ray diffraction (XRD) was used to examine phase-related structural features, while gamma-ray transmission was measured with ²⁴¹Am (59.5 keV) and ¹³⁷Cs (661.7 keV) using a collimated NaI(Tl) spectrometric arrangement. At 59.5 keV, the linear attenuation coefficient increased from 0.3909 cm⁻¹ for the control to 0.6423, 1.8127, 2.5464, 2.6205, and 2.7828 cm⁻¹ for Fe-, HfO₂-, WO₃-, BaSO₄-, and Bi₂O₃-containing specimens, respectively. The corresponding half-value layer decreased from 1.773 cm to 1.079, 0.382, 0.272, 0.265, and 0.249 cm. At 661.7 keV, the modified specimens remained more attenuating than the control but clustered within 0.1731–0.1842 cm⁻¹. Within the tested conditions, the fabricated formulations showed much stronger discrimination at 59.5 keV than at 661.7 keV, with Bi₂O₃-, BaSO₄-, and WO₃-containing specimens forming the strongest low-energy group. Because the pressed-disc densities differed between the formulations, these linear-attenuation differences are interpreted as the combined response of additive identity and the resulting bulk density/compaction rather than as a chemistry-only effect. This study is a fixed-loading, two-energy screening comparison rather than a concentration or structural optimization study. Full article

The rapid advancement of artificial intelligence (AI) necessitates high-performance computing architecture. While compute express link (CXL) technologies facilitate memory expansion, conventional dynamic random-access memory (DRAM) encounters fundamental limitations in power consumption and scalability. Consequently, 1-transistor-n-capacitor (1T-nC) ferroelectric random-access memory (FeRAM) has emerged as a compelling non-volatile candidate; however, process-induced variations substantially degrade its operational reliability. This study investigates the impact of wet etch-induced capacitor length (L_cap) variations and atomic layer deposition (ALD)-induced electrode work function (WF) deviations on the sensing margin of 1T-nC FeRAM. The analysis employs Sentaurus TCAD (Synopsys, Inc., Mountain View, CA, USA, Version T-2022.03) simulations calibrated via the Preisach model, utilizing empirical positive-up-negative-down (PUND) measurements of 7 nm Hf_0.5Zr_0.5O₂ (HZO) capacitors. The results demonstrate that geometric shadowing during wet etching induces non-uniform L_cap profiles. Configuring the bottommost capacitor L_cap to 80 nm secures a sensing margin exceeding the 150 mV DDR4 specification. Furthermore, TiN oxidation during ALD shifts the plate line work function (WF_PL). Constraining WF_PL between 4.51 eV and 4.71 eV at L_cap = 90 nm ensures stable read operations, with this window narrowing further as L_cap is scaled down. By establishing these theoretical boundary conditions, this study provides predictive design guidelines for high-density architectures. Ultimately, mitigating L_cap geometric dispersion and suppressing TiN oxidation are imperative for guaranteeing sufficient sensing margins, thereby advancing scalable, high-density 1T-nC FeRAM solutions for next-generation AI workloads. Full article

In gas-insulated equipment, the Ag surfaces of silver-plated contacts are directly exposed to the insulating gas. Poor compatibility between the gas and Ag may therefore compromise the insulation performance and operational reliability of the equipment. To investigate the gas–solid compatibility between the environmentally friendly insulating medium HFO-1234ze(E) and Ag components, the interactions between HFO-1234ze(E) and the Ag (1 1 1) surface were examined at the microscopic level using density functional theory (DFT). First, the reactive regions of HFO-1234ze(E) were identified through frontier molecular orbital and electrostatic potential analyses. Subsequently, the adsorption energies, charge transfer, charge density difference distributions, and other microscopic parameters were calculated and compared for HFO-1234ze(E) and SF₆ adsorbed on pristine Ag (1 1 1). Molecular dynamics simulations and activation barrier calculations for representative bond dissociation pathways were then performed to evaluate the dynamic and kinetic stability of the adsorption system. Finally, the effects of a Ag vacancy defect on the adsorption characteristics were investigated. The results show that the interaction of HFO-1234ze(E) with pristine Ag (1 1 1) is substantially weaker than that of SF₆ with the same surface. HFO-1234ze(E) remains structurally stable throughout the molecular dynamics simulations. The vacancy defect only enhances the adsorption strength and interfacial electronic interactions. These findings indicate that HFO-1234ze(E) exhibits favorable initial adsorption compatibility with Ag (1 1 1) under the computational conditions considered. Full article

HfO₂-based ferroelectrics have extended a familiar CMOS high-κ dielectric into a materials platform for nonvolatile memory, low-power logic, and in-memory hardware. This review examines thickness engineering in hafnia, especially Hf_0.5Zr_0.5O₂ (HZO), through the state produced during fabrication, the voltage and time available for switching, and the signal retained during operation. Representative quantitative comparisons retain stack, anneal, electrical state, and endpoint definitions; they show that conditioning and drive voltage can change the apparent thickness trend substantially. Capacitor memory, FeFETs, tunnel junctions, negative-capacitance transistors, and computing devices are compared through architecture-specific read margins and failure criteria. The main unresolved challenge is to isolate thickness effects from coupled process and interface changes and establish reproducible, device-specific operating windows. Full article

Recently, significant beryllium mineralization was discovered along faults within syenogranites in the Yama area of the Qilian Orogen, NW China. This study presents a comprehensive analysis of the geochemical compositions of these syenogranites, along with zircon U–Pb geochronology, Hf isotopic data, and trace element analyses. Barren and beryllium-bearing syenogranites yielded weighted mean ²⁰⁶Pb/²³⁸U zircon ages of 437.7 ± 3.3 Ma and 432.0 ± 2.3 Ma, respectively, indicating a consistent emplacement age in the early Silurian. Their geochemical characteristics are slightly peraluminous, with high alkali contents; relatively low (K₂O + Na₂O)/CaO and Fe₂O₃^T/MgO ratios, low concentrations of Zr + Nb + Ce + Y, strongly negative Eu anomalies, high Rb/Sr and Rb/Ba ratios, and negative correlations between Rb and Th, all indicative of fractionated S-type syenogranites. Furthermore, geochemical data combined with negative zircon ε_Hf(t) values suggest derivation from the partial melting of Paleoproterozoic pelitic-rich protoliths within a relatively shallow, reworked lower crust during an early Silurian syn-collisional setting. Negative ΔFMQ values and low Ce⁴⁺/Ce³⁺ ratios, along with relatively high La contents and Sm_N/La_N ratios in a few zircon grains, as well as relatively low whole-rock Nb/Ta and Zr/Hf ratios, imply a certain initial-stage magmatic–hydrothermal beryllium-mineralization potential for the studied syenogranites. Full article

The Shitoukoumen area in central Jilin Province, NE China, preserves a Permian blocks-in-matrix assemblage containing pre-Permian mafic and sedimentary blocks that provides an important record of the Paleozoic evolution of the eastern Paleo-Asian Ocean. We present petrographic, zircon U-Pb geochronological and Lu-Hf isotopic, and whole-rock geochemical and Sr-Nd isotopic data for newly discovered amphibolites. Zircons from the amphibolites show metamorphic characteristics, and zircon U-Pb dating yielded an age of 503 ± 4 Ma, recording Late Cambrian metamorphism. The amphibolite is tholeiitic, with low SiO₂ (48.46–52.22 wt.%) and K₂O (0.07–0.17 wt.%) and relatively high MgO (4.48–6.31 wt.%), Fe₂O₃^T (11.01–15.48 wt.%), and CaO (9.07–12.55 wt.%). It has low total REE abundances and slightly LREE-depleted patterns, with no negative Nb-Ta anomalies. Its ε_Hf(t) and ε_Nd(t) values are +14.9 to +20.4 and +7.2 to +8.4, respectively, while the initial ⁸⁷Sr/⁸⁶Sr ratios are slightly elevated, consistent with seawater alteration. These geochemical and isotopic characteristics are consistent with an N-MORB-like oceanic crustal protolith derived from partial melting of a depleted spinel-facies mantle source. Together with the spatial association with the Zhangjiatun–Toudaogou–Xiaosuihe SSZ ophiolite, the amphibolite may represent a component of a metamorphic sole related to Late Cambrian intra-oceanic subduction initiation of the Paleo-Asian Ocean, although this interpretation remains tentative. Full article

Infrared stealth for high-temperature targets is of considerable significance. Multilayer-film-based selective thermal emitters can effectively regulate thermal radiation, thereby offering a promising solution to stealth challenges. In this work, a novel selective thermal emitter based on a multilayer thin film is designed. The film consists of ten layers constructed from five materials: TiO₂, Al₂O₃, HfO₂, Ge, and SiO₂. Experimental measurements show that, at room temperature, the multilayer film exhibits an emissivity of 0.199 in the mid-infrared band and 0.219 in the long-wave infrared band, demonstrating excellent infrared stealth performance. In the non-detection band (5–8 µm), an emissivity of 0.774 is achieved, enabling effective heat dissipation. At elevated temperatures up to 500 °C, the multilayer film still maintains favorable infrared stealth and radiative cooling performance. Furthermore, experiments demonstrate that the film possesses outstanding radar-wave transparency in the 2–18 GHz band, making it suitable for subsequent integration with radar-absorbing materials to form composite structures and achieve compatible stealth. The designed and fabricated multilayer film provides a new reference for the realization of high-temperature-resistant selective thermal emitters. Full article

Cenozoic felsic magmatism along the northern Tibetan Plateau records the evolution of thickened continental crust, yet Miocene intrusions in the East Kunlun Orogen remain poorly constrained. Here we integrate field and petrographic observations with zircon U-Pb geochronology, zircon Lu-Hf isotopes, and whole-rock geochemistry for the Ganquanhe biotite monzogranite porphyry. Sample TW6 contains two zircon ²⁰⁶Pb/²³⁸U age populations at 14.8 ± 0.2 Ma and 17.5 ± 0.2 Ma, whereas the coherent TW7 population yields the preferred crystallization age of 17.6 ± 0.2 Ma; these uncertainties include a conservative 1% external reproducibility term. The overlapping ε_Hf(t) ranges of the two TW6 age groups support a common magma source and indicate that the younger dates most likely record Pb loss rather than a separate magmatic event. The high-K calc-alkaline, metaluminous to weakly peraluminous rocks have low Y and Yb, high Sr/Y and (La/Yb)_N, fractionated rare earth element (REE) patterns, and weak Eu anomalies. Low MgO, Cr, and Ni contents, negative zircon ε_Hf(t) values, and Mesoproterozoic T_DM2 ages indicate derivation mainly from ancient, garnet ± amphibole-bearing lower crust. Whole-rock zircon saturation temperatures of 760–782 °C and Sr/Y- and (La/Yb)_N-based crustal-thickness estimates of approximately 72–77 km indicate melting within a warm, strongly thickened crust. Major-element source discrimination further favors an amphibolitic lower-crustal source with possible subordinate graywacke–orthogneiss components. The intrusion therefore records Early Miocene lower-crustal melting within a collisional to post-collisional setting along the northern Tibetan Plateau. Full article

The greenstone belt of the North China Craton (NCC) records the crustal evolution from the Neoarchean to the post-Archean period, offering critical insights into the ancient tectonic background. This study focuses on the late Paleoproterozoic granitoids in the Daxigou area, located within the greenstone belt of the Qianhuai Block along the northern margin of the NCC. Zircon U–Pb dating indicates that two representative samples (H1 and HZK97-2) were emplaced at 1849 ± 2.1 Ma and 1852 ± 2.0 Ma, respectively (ca. 1.85 Ga). Both samples are characterized by high K₂O (3.99–6.55 wt%) and Na₂O + K₂O contents (4.12–7.92 wt%), high 10,000 × Ga/Al ratios, zircon saturation temperatures (>800 °C), and seagull-type REE patterns, and are identified as A2-type granitic rocks. The Daxigou granitoids show LREE enrichment, negative Eu anomalies (δEu = 0.45–0.63), LILE enrichment, and Nb–Ta–Ti depletion, defining the arc-like trace-element signatures. Integrated with their low Mg# (0.15–0.20), Cr (12–21 ppm), and Ni (0.8–2.5 ppm) contents, negative zircon εHf(t) values (−4.25 to −0.17), Neoarchean Hf model ages (2.5–2.7 Ga), near-chondritic to slightly subchondritic Nb/Ta ratios (15.4–18.3), and high Zr/Hf ratios (41.2–44.1), these features indicate an inheritance from warm subduction-generated Neoarchean TTG protoliths. We propose that the arc-like signatures of the Daxigou granitoids reflect the source inheritance from Neoarchean TTG protoliths. At ca. 1.85 Ga, under an extensional setting, the ancient lower crust (TTG) underwent decompression melting, producing A2-type granitic rocks. They record a transition of the tectonic setting from Neoarchean warm subduction to late Paleoproterozoic post-orogenic extension. Full article

To reveal the uranium enrichment mechanism in the Daqing Placanticline area, northern Songliao Basin, this study collected a total of 41 samples of three geological types, namely uranium ore, uranium-mineralized sandstone and host rock from the Upper Cretaceous Sifangtai Formation. Combined with 109 geochemical datasets from exploration, systematic analyses were performed on major elements, trace elements, rare earth elements (REE), total organic carbon (TOC), total sulfur and other key geochemical parameters. The results indicate that uranium ore and mineralized sandstone are generally characterized by high TOC, high total sulfur, low Th/U and low Fe₂O₃/FeO ratios, while host rocks show the opposite geochemical assemblage, suggesting uranium enrichment took place in a strongly reducing sedimentary environment. The ore-forming system is significantly enriched in trace elements including U, Pb, Mo, Ba, Zn and Y, and depleted in Cu, Co, Ni, Cr, Sr, Nb, Ta, Zr and Hf. Among these elements, Mo and Pb have an extremely close relationship with uranium mineralization and can be used as effective ore-forming indicator elements. Uranium ore, mineralized sandstone and host rock exhibit consistent REE distribution patterns, implying that the strata in the study area share uniform provenance, sedimentary environment and tectonic setting. Some high-grade uranium ores are obviously enriched in heavy rare earth elements (HREE), demonstrating fluid modification during the late mineralization stage. Combined with regional tectonic evolution and hydrocarbon migration features, this study concludes that sandstone-type uranium deposits in the Daqing Placanticline mainly underwent two stages of mineralization: supergene fluid mineralization and superimposed reworking by deep hydrocarbon-bearing reducing fluids. Full article

High-power laser systems impose stringent requirements on the laser-induced damage threshold of optical thin films. Post-deposition thermal annealing has been demonstrated as an effective approach to enhancing the LIDT of HfO₂-based coatings; however, its effects on antireflection coatings—particularly those employing non-quarter-wave designs that offer industrial advantages such as fewer layers and lower fabrication cost—remain insufficiently investigated. In this work, non-quarter-wave HfO₂/SiO₂ multilayer antireflection films were fabricated by ion beam-assisted electron beam evaporation, and the effects of thermal annealing on their laser-induced damage characteristics were systematically investigated. Experimental results show that the effect of thermal annealing between 300 and 700 °C on the laser damage resistance of the antireflection coating is not monotonic: the laser-induced damage threshold rises from 27.6 J/cm² in the as-deposited state to 36.7 J/cm² at 500 °C, an improvement of approximately 33.1%, and then falls at 600 °C and 700 °C, while remaining above the as-deposited value throughout. This non-monotonic behavior originates from a competition between two contributions. On the one hand, the repair of oxygen vacancies, the densification of the film, and the growth of the crystallites continuously reduce the population of initiating absorbers and improve heat dissipation. On the other hand, the penalties arising from the exhaustion of the free volume and from the accumulation of tensile stress accelerate in the upper part of the temperature range, and their influence on the threshold progressively outweighs the gain produced by the former. Annealing at 500 °C is therefore the optimum state determined by this competition. Full article

Decarbonizing shipping requires reducing emissions without compromising the performance of large commercial vessels. Nuclear propulsion using small modular reactors (SMRs) has recently attracted renewed interest as a long-term alternative to fossil-fuel engines for large container ships. This study provides a technical, environmental, and economic assessment of SMR propulsion for a typical 15,000-TEU container ship, compared to conventional heavy fuel oil (HFO) propulsion. The analysis covers propulsion power requirements, energy conversion efficiency, additional electrical power needs, operational emissions, and total costs over 25 years. Under the study’s assumptions, the conventional system consumes about 50,400 tonnes of HFO annually, resulting in approximately 156,940 tonnes of CO₂ emissions per year, along with significant NO_x, SO_x, particulate, and CO emissions. A 70 MWe SMR-based propulsion design is then evaluated, considering energy conversion losses and the ship’s auxiliary power needs. The power balance indicates that the proposed SMR system can meet propulsion demands and provide surplus electrical capacity. Economically, the estimated 25-year total cost for the SMR option is about USD 376.7 million, compared to USD 452.0 million for the HFO case. Sensitivity analysis shows that this economic advantage depends on HFO prices, SMR capital costs, the discount rate, and operating life. Overall, SMR propulsion appears to be a technically and economically viable option for large container ships, though its adoption will depend on regulatory requirements, safety standards, infrastructure, and further advancements in marine nuclear technology. Full article