Arc magmatism plays a crucial role in constraining the tectonic evolution of orogenic belts. This study focuses on two phases (Phase I and II) of the Early Palaeozoic intrusive rocks in the Wude area, located in the western Bainaimiao arc terrane (BAT), southeastern Central Asian Orogenic Belt. We performed whole-rock geochemistry, zircon U–Pb chronology, and Hf isotope, amphibole geochemical analyses. Phase I comprises granites and quartz diorites with zircon U–Pb age range from 464 to 457 Ma. These rocks are medium- to high-K calc-alkaline, fractionated I-type granites exhibiting an arc-like geochemical signature, such as enrichments in Rb, Ba, Th, U, Pb, and Sr and depletions in Nb, Ta, Ti, and P. Phase II intrusive rocks consist of congeneric hornblendites, diorites, plagioclase porphyrite, and granite porphyry, with zircons U–Pb ages from 446 to 442 Ma and positive εHf(t) values (+ 1.50 to + 13.39). These rocks display island arc magma compositions characterized by enrichments in large-ion lithophile elements (e.g., Ba, U, Pb, and Sr) and depletions in high-field-strength elements (e.g., Nb, Ta, Zr, Hf, and Ti). Amphiboles from the hornblendites and diorites in the Wude area are classified as magnesio-hornblendes, indicating crystallization temperatures of 702.5–763.6 °C, depths of 13.3–19.1 km (based on TiO2 contents), and REDOX conditions of ΔNNO + 0.52 to 1.55. The positive zircon εHf(t) values and calculated crystallization pressures of 3.09–4.95 Kbar (13.3–19.1 km) support the formation of cumulate hornblendites and diorites in a juvenile island arc setting within the middle crust. These findings provide insights into the tectonic and paleogeographic evolution of the western Bainaimiao Arc during the Early Palaeozoic. Geochronological and geochemical data suggest a tectonic transition occurred between Phase I and Phase II. Based on the age of the ophiolitic mélange and previous works, this transition may reflect a shift from a south-dipping subduction of the Paleo-Asian Ocean to a north-dipping subduction of the southern Bainaimiao Ocean.

The efficient utilization of manufactured stone powder in cement-based materials remains challenging due to its low pozzolanic activity, weak interfacial bonding, and high water-demand, making modification essential for enhancing its application potential. This study systematically reviews the physicochemical characteristics of stone powders from different lithologies and elucidates the micro-mechanisms of three modification processes: mechanical activation, chemical treatment, and their combination. Modified stone powders on the workability, mechanical properties, shrinkage, and durability of cement-based materials are compared. Meanwhile, the existing problems and possible potential directions were also presented for the comparative analysis of the modification processes. The findings of this review offer a scientific basis for the high-value utilization of stone powder and the selection of appropriate modification techniques.

Diversity and composition of plants and soil biota are critical determinants of fundamental ecosystem functions. Although the compositional responses of organisms across trophic levels to global change drivers and ecosystem management strategies have been well documented, their intra-annual variations and main drivers remain largely unknown. We hypothesized that the intra-annual dynamics of each biotic group would be driven by distinct factors: light availability for plants, temperature and plant growth for soil microbe, and soil nutrients for nematodes. We investigated the taxonomic diversity and community composition of plants, soil bacteria, fungi, and nematodes across five months in a grassland experiment following eight years of factorial treatments involving nitrogen (N) addition and mowing. We found significant intra-annual variations in the community composition of plants, soil bacteria, fungi, and nematodes. However, the primary drivers of these variations differed among biotic groups. Specifically, light availability, plant above-ground biomass, temperature, and soil nutrient dynamics played dominant roles in shaping plant, bacterial, fungal, and nematode communities, respectively. Neither N addition nor mowing significantly altered the intra-annual variation pattern of biotic groups, except for plants. Nitrogen addition significantly affected the intra-annual stability of community compositions across all biotic groups and disrupted their inherent correlations. By elucidating the key drivers of seasonal variations in the community composition of plants, bacteria, fungi, and nematodes, this study advances our mechanistic understanding of intra-annual dynamics in grassland ecosystems under nutrient enrichment and provides insights for biodiversity conservation in a changing world.

Grasslands are vital for global carbon (C) cycling, with belowground organs crucial for C sequestration. Mowing, a common practice in nutrient‐enriched grasslands, affects biodiversity positively but reduces aboveground biomass. Its impacts on belowground C stocks remain unresolved, posing knowledge gaps in understanding community assembly and belowground C responses due to limited species‐level belowground biomass data. With a long‐term field experiment in temperate steppe of northern China, we investigated the impacts of annual mowing on belowground biomass C stocks at both species and community levels under ambient and N addition conditions. Mowing significantly increased belowground C stocks but not aboveground C stocks. Mowing induced reordering of plant species in the community, and facilitated the growth of a sedge Carex duriuscula with the highest belowground:aboveground biomass ratio, which accounted for the positive responses of belowground C stocks. Under projected warmer and drier climate and more frequent fire across global grasslands, mowing would be one of the important nature‐based solutions to boost grassland C storage by moving C from vulnerable aboveground pools to the long‐lasting belowground pools.

The deterioration of concrete materials in marine environments is mainly attributed to the attack of chloride and sulphate. In this work, the cement mortar was subjected to immersion in chloride and sulphate solutions. The quantity of chloride ions within the cement mortar was subsequently determined, and the surface chloride concentration and chloride diffusion coefficient were calculated. Furthermore, a coupled diffusion-reaction model was developed for combined chloride and sulphate with different chloride and sulfate concentrations. The interaction between chloride and sulphate results in the slowing down of chloride ion transport and a reduction in surface chloride concentration. The bound chloride ions, including physically and chemically bound chloride ions, are broken down duo to the sulphate. The inhibition of ion transport by chemically bound AFm is more pronounced than the physical adsorption by C-S-H. The proposed model can well simulate the evolution of corrosion products during chloride and sulphate ion transport.

The consumption of the Palaeo-Asian Ocean domain triggered substantial resources and environmental effects, but the final suture timing remains debated. This study presents the zircon U-Pb age and Hf-O isotope, whole-rock element and Sr-Nd-Pb isotope data from the Elitu Formation trachyandesite and rhyolitic tuff in the Bainaimiao arc belt. The zircon U-Pb ages (260-280 Ma) indicate that the Elitu Formation volcanism erupted at the Kungurian to Capitanian. Trachyandesites exhibit an arc-like whole-rock trace element composition and have enriched Sr-Nd-Pb isotopic composition (ISr(t) = 0.7062-0.7065; epsilon Nd(t) = -8.8 to -9.4; (206Pb/204Pb)t = 17.14-17.31) and high zircon 618O (6.08%o-7.59%o) values, which are derived from the partial melting of the lithosphere mantle metasomatised by ancient sediment-derived melts. Rhyolitic tuffs have variable epsilon Hf(t) (-7.15 to +10.47) and low 618O (4.99%o-6.21%o) values and exhibit affinities with I-type felsic rocks. They mainly originate from the partial melting of the basement of the Bainaimiao arc belt. Our compiled geochemical and geochronological data indicate that there were significant differences between the Early to Middle Permian Elitu Formation volcanic rocks and intrusive counterparts and the Early to Middle Triassic magmatic rocks from the Bainaimiao arc belt, and the Late Permian was the key tectonic transition period. The Late Permian transition was compatible with the regional crustal-shortening deformation, greenschist facies metamorphism and shift of deposition environment. This study argues that the Elitu Formation volcanism should be subduction-related and predate the final suture of the Palaeo-Asian Ocean domain at the Changhsingian. The suture of the Palaeo-Asian Ocean domain was not the original trigger of the Kungurian climate change in the North China Craton.

Petrological, geochronological, and geochemical data from the volcano-sedimentary sequences, granitoids, and ophiolite relics of central Inner Mongolia, China, were used to reconstruct the subduction and final closure of the Hegenshan Ocean. Geochronological dating and compilation reveal four phases (ca. 360-355 Ma, 348-320 Ma, 320-310 Ma, and 310-275 Ma) of magmatism in the Uliastai continental margin. The ca. 356 Ma I-type Halatumiao granodiorite and Amanwusu ophiolite relics are subduction-related, and the Halatumiao granodiorite provides solid evidence of the northward subduction of the Hegenshan Ocean beneath the Uliastai continental margin at ca. 360-355 Ma. The ca. 348-320 Ma and 320-310 Ma volcanic rocks and granitoids constitute two linear magmatic belts roughly parallel to the ErenhotHegenshan ophiolite belt, which record two phases of continental arc magmatism in the Uliastai continental margin. Overall, the ca. 360-310 Ma arc magmatism shows landward migration and then oceanward migration in the Uliastai continental margin, which indicates advancing subduction and subsequent slab steepening of the Hegenshan Ocean. By contrast, the ca. 310-275 Ma magmatic rocks are dominated by I- and A-type felsic volcanic rocks, granites, and dikes, which are post-accretionary, extension-related, and pervasive in the Uliastai continental margin and Erenhot-Hegenshan ophiolite belt. A provenance shift was identified between the Benbatu and Amushan formations of the Amanwusu area of the Erenhot-Hegenshan ophiolite belt. The early detritus was derived from the early Paleozoic rocks in the Sonid Zuoqi arc belt, whereas the late detritus originated from the Early Carboniferous ophiolite relics in the Erenhot-Hegenshan ophiolite belt. The provenance shift and emplacement of pervasive extension-related magmatic rocks imply a Late Carboniferous closure of the Hegenshan Ocean. The Late Carboniferous oceanic closure event in the north of the southeast Central Asian Orogenic Belt is also evidenced by the transition of Hf isotopic composition of zircons dated between ca. 360-310 Ma and 310-275 Ma.

Early Cretaceous intraplate volcanic rocks are widespread in NE Asia, but their origin remains controversial. This work presents zircon U-Pb ages, whole-rock element and Sr- Nd isotope data for mafic volcanic rocks from the Erlian Basin, a wide rift basin in NE Asia. There were two episodes of Early Cretaceous mafic volcanism in the Erlian Basin, and the eruptions show contrasting geochemical com- positions. The early mafic volcanic rocks, with U-Pb ages of ca. 140-135 Ma, show slightly depleted Sr-Nd isotope compositions (I Sr (t) = 0.7042-0.7052; epsilon Nd (t) = + 0.82 to + 3.0) and arc-like trace-element composi- tions, which are derived from subduction- related fluid/melt metasomatized lithosphere mantle. The late mafic volcanic rocks (dated at ca. 125 Ma) have enriched Sr-Nd isotopes (I Sr (t) = 0.7055-0.7077; epsilon Nd (t) = - 0.50 to - 2.67) and oceanic-island basalt (OIB)-like trace-element compositions, revealing the metasomatism of melts from crustal materi- als and asthenosphere mantle. The two types of mafic volcanic rocks may record the in- teractions of the mantle and melts from the subducted paleo-Pacific oceanic slab at dif- ferent depths. The landward-then-oceanward migration pattern of the Mesozoic volcanism from NE Asia can be explained by the flat sub- duction and subsequent slab roll-back of the Paleo-Pacific Ocean, consistent with migra- tion patterns from the North China Craton and South China Block, implying similar Ju- rassic-Cretaceous subduction evolution along the entire East Asia margin. Some Late Juras- sic to Early Cretaceous dates from east Mon- golia and the southern margin of the Erlian Basin diverge from this trajectory. In combi- nation with previous studies, we suggest that the Early Cretaceous pervasive intraplate vol- canism in the Erlian Basin and adjacent areas of NE Asia mainly resulted from the slab roll- back of the Paleo-Pacific Ocean with a com- bined effect from the post-collision extension of the Mongol-Okhotsk orogen.

We construct a sequence of explicit blow-ups and blow-downs on an irreducible compact Hermitian symmetric spaces $X$ which transforms it into a projective space of the same dimension. Moreover, this resolves a birational map given by Landsberg and Manivel. Centers of the blow-ups for $X$ are constructed by loci of chains of minimal rational curves and centers of the blow-ups for the projective space are constructed from the variety of minimal rational tangents of $X$ and its higher secant varieties. The result was known in the special case where $X$ is of rank 2 and could be found in Zak's monograph "Tangents and secants of algebraic varieties."

This paper describes a balanced frequency shift keying (FSK) modulation, namely quasi-balanced FSK (QB-FSK), for energy-efficient high-data-rate communication. Not suffering from data-pattern dependency, the proposed modulation method enables frequency modulation (FM) over 100 Mb/s by utilizing a wideband phase-locked loop (PLL). The QB-FSK signal is generated with the same baseband clock frequency as the non-return zero (NRZ)-coded binary FSK (BFSK) signal, resulting in improved bandwidth efficiency compared to other balanced FSK signals. For demodulation, the receiver employs a sideband energy detection (SB-ED) method. A FM discriminator converts the QB-FSK signal to an on-off keying (OOK) signal. After that, a band-pass filter (BPF) is used to filter out 1/f noise and dc offset. Based on the proposed QB-FSK modulation and the SB-ED method, a prototype FSK transceiver is implemented in 65-nm CMOS for high-data-rate sub-6-GHz proprietary wireless connectivity. The receiver successfully demodulates data at a rate of 200 Mb/s with a sensitivity of -67 dBm, while the transmitter can achieve a maximum data rate of 400 Mb/s. The 200-Mb/s transceiver achieves an energy efficiency of 0.14 nJ/b.

Rodingite, a metasomatic rock type related to the serpentinisation of ultramafic rocks, occurs as dykes or lenses in serpentinite of the ophiolitic melange. The formation age, protolith and metamorphic context of the rodingites are crucial for evaluating the hydrothermal activity of the ancient ocean floor and the tectonic history of the ophiolite. This study presents particular research on metamorphic petrology, geochemistry and zircon U-Pb chronology of rodingites and their associated mafic-ultramafic rocks in the Baixingtu ophiolite, the middle segment of the Erenhot-Hegenshan ophiolite belt (EHOB), southeastern Central Asian Orogenic Belt. The mean metamorphic ages of rodingites are 345.8 +/- 3.8 Ma, 339.9 +/- 4.8 Ma, and 344.5 +/- 9.2 Ma. According to the chlorite thermometer, the final mineral assemblages of rodingites formed at temperatures ranging from 114.99 degrees C to 351.10 degrees C. The high oxygen fugacity of nascent clinopyroxenes and the negative anomaly of Ce in adjacent serpentinites (delta Ce = 0.34-0.77) prove that rodingitisation occurs in shallow oceanic crust by the reaction of seawater with ultramafic rocks to produce Ca-rich fluids. Accordingly, the Baixingtu ophiolite was produced by an ocean floor metamorphism, whose rodingitisation occurred shortly after the formation of the oceanic crust. Combined with other ophiolite data from the EHOB, the Hegenshan Ocean was constantly generating new oceanic crust in the Early Carboniferous.

We prove a gap rigidity theorem for diagonal curves in irreducible compact Hermitian symmetric spaces of tube type, which is a dual analogy to a theorem obtained by Mok in noncompact case. Motivated by the proof we give a theorem on weaker gap rigidity problems for higher dimensional submanifolds.

为优选高延性水泥基复合材料(HDCC)用短切聚乙烯醇(PVA)纤维的长度,采用6 mm、9 mm、12 mm、18 mm和24 mm五种长度的PVA纤维,在体积掺量为1.0％的情况下制备HDCC,研究PVA纤维长度对HDCC工作性能、力学性能和纤维桥联能力的影响.结果表明:随着纤维长度的增加,HDCC新拌浆体流动性逐渐降低,当纤维长度从6 mm增加到9 mm时浆体流动性显著下降39％;纤维的掺入提升了 HDCC的抗压、抗折强度,但其增幅与纤维长度相关性不大;掺入18 mm纤维制备的HDCC展现出最高的弯曲强度,而掺入9 mm纤维制备的HDCC展现出最高的跨中挠度和弯曲耗能;随着纤维长度的增加,纤维桥联应力和桥联余能均增大,但由于纤维断裂效应越显著,纤维桥联应力和桥联余能增幅逐渐变缓.基于HDCC工作性能、力学性能以及纤维桥联能力的试验与计算结果,9 mm长度的PVA纤维是较为合适的选择.

The notion of admissible pairs of rational homogeneous spaces of Picard number one and their rigidity in terms of the geometric substructures was formulated by Mok and Zhang. The rigidity is known for subdiagram type. While when the admissible pair is of deletion type, the rigidity no longer holds and we need additional conditions. Mok gave a general criterion to handle the admissible pairs which are not of subdiagram type. In this short note we give some examples of admissible pairs of irreducible compact Hermitian symmetric spaces of deletion type to be rigid under the assumption of rational saturation, as an application of Mok's theorem.

Ultramafic-mafic rocks from the middle to lower crust document the history of the magmatic and tectonic evolution of the volcanic arc. This study presents particular research of geochemistry, zircon U-Pb chronology, Hf isotope, and thermodynamics of the early Paleozoic cumulate hornblendites and other intrusive rocks in the Wude area, western Bainaimiao arc terrane, southeastern Central Asian orogenic belt. Zircons from hornblendites and congenetic diorites show U-Pb ages from 446 Ma to 443 Ma, with positive εHf(t) values (+1.50 to +13.39). Another period of intrusive rocks contains granites and quartz diorites, which intruded from 464 Ma to 457 Ma. The main minerals in hornblendite are magnesio-hornblendes, with several of them belonging to pargasite and tschermakite. Amphibole TiO2 contents in hornblendite indicate crystallization between 707.7 and 761.8 °C with pressures of 3.71–4.95 Kbar. The chemical composition of amphibole in diorite reveals a crystallization temperature of 702.5–763.6 °C and a pressure of 3.09–4.79 Kbar. Accordingly, the above results shed the tectonic and the paleogeographic model of the western Bainaimiao Arc in the early Paleozoic. The “southern Bainaimiao Ocean” was a nascent back-arc basin, and the study area experienced a reversal of the subduction polarity at about 450 Ma.

为提高机制砂生产过程中产生的废弃石粉的资源化利用率,并降低高延性混凝土的材料成本,采用石灰岩石粉部分取代胶凝材料制备机制砂高延性混凝土,研究石粉掺量对机制砂高延性混凝土流动性、抗压强度、抗折强度和直接拉伸性能的影响.结果表明,随石粉掺量的增加,机制砂高延性混凝土的流动性略有下降,抗压、抗折强度降低.石粉掺量为30％和40％时,机制砂高延性混凝土的极限拉伸应变显著提高,具有更优的变形能力,并具备一定的经济效益.

基于桥联法则理论、经微观力学设计而成的高延性水泥基复合材料(HDCC)以其拉伸荷载下具有的多缝开裂和应变硬化性能而优于普通混凝土,然则其发展仍受制于高制备成本及碳排放.近10年来,绿色经济性地质聚合物/碱激发材料与纤维复合增韧的高延性复合材料(HDGC)得到研究与发展.本文在概述地质聚合物/碱激发材料反应机理及HDCC材料设计理论的基础上,主要综述了 HDGC基本性能与微结构的已有最新研究进展.研究表明,制备HDGC具有可行性且制备的HDGC表现出高延性复合材料所具备的力学响应特点,包括压缩、拉伸应变硬化、界面微观力学、弯曲、抗冲击性能等.然而,受材料组成复杂等因素影响,HDGC力学和微结构依赖于地质聚合物/碱激发材料基体化学性质的改变.HDGC同时具有更小的裂缝宽度而利于材料自修复、较大收缩值以及潜在的良好耐久性.此外,基于有限研究,对比了 HDGC与HDCC的相似与差异,以期更好地了解地质聚合物/碱激发材料被用作HDCC替代品时应注意的条件.最后进一步对HDGC存在的问题和研究方向做出了总结与展望.

The shape characteristics of blasting fragments are important for analyzing the blasting fragmentation mechanism and evaluating the fragmentation energy efficiency. In this study, through field blasting experiments and morphological parameter measurements, fractal theory was employed to reveal the fractal characteristics of rock blasting fragmentation. Using the fragmentation fractal dimension, the probability of rock blasting fragmentation was analyzed, and a predictive formula for the specific surface area (SSA) of blasting fragments was established. For fragments, the fractal dimensions of the particle size distribution calculated using different characteristic sizes were less than 2.0. When the fragment size distribution had dual fractal characteristics, significant differences were observed in the scale-free interval and fragmentation fractal dimension. Within the large scale-free interval, the fragmentation fractal dimension was mostly greater than 2.3, whereas within the small scale-free interval, it tended to be less than 2.0. The rock fragmentation process typically consisted of two or three breakage levels, with a similarity ratio of 0.5 and an average fragmentation probability ranging from 0.44 to 0.71. The predicted SSA of the blasting fragments closely matched the measured values. The findings provide valuable insights into the mechanism of rock blasting fragmentation and the calculation of fragmentation energy consumption.

As the demand of high-speed communication is growing for mobile connectivity, the design of a low-power high-data-rate wireless transceiver is essential. Even though the binary FSK (BFSK) modulation is a popular choice for low-power transceiver systems [1]–[5], it has difficulty in achieving a high data rate unless an open-loop oscillator or an injection-pulling oscillator [6] is employed. The direct modulation of the VCO with an open-loop method or within a narrowband PLL suffers from the pulling effect. A closed-loop modulation based on the PLL is challenging for the high data rate due to a limited loop bandwidth or a delay mismatch in the case of the two-point modulation. Moreover, the closed-loop BFSK modulation suffers from a data-pattern-dependency problem when a wideband PLL is considered. The binary frequency-domain OOK (BFOOK) modulation method provides a way of achieving a fully-balanced FSK modulation [7]–[8], so that a wideband PLL can be designed to minimize the VCO pulling effect. The BFOOK modulation, however, occupies twice as much bandwidth as the conventional BFSK modulation. In this work, we propose a quasi-balanced FSK (QB-FSK) modulation to achieve enhanced bandwidth efficiency, while having negligible data-pattern dependency. Based on the proposed modulation method, we present a sub-6GHz FSK transceiver that achieves the highest data rate with the PLL-based modulation.