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Chitosan (CS) was selected as the carbon source, and the Chitosan/dicyandiamide (CS/DCDA) precursors with hydrogen bonding interactions were prepared by freeze-drying and normal drying, and the carbon-Chitosan/graphite carbon nitride (C-CS/g-C3N4) composites were obtained after calcination. The results show that the freeze-drying process can produce more hydrogen bonding interaction between chitosan and dicyandiamide (DCDA) and more pores through recrystallization. More composite carbon is formed in the C-CS/g-C3N4-2 composite obtained after calcination. More hydrogen bonds are broken, releasing more N lone pairs of electrons, which not only facilitates the n−π* electron leap, but also facilitates the separation and photogenerated electron-hole, and provides a large number of reactive sites for photocatalytic degradation of pollutants. This results in better photocatalytic performance of C-CS/g-C3N4-2. [ABSTRACT FROM AUTHOR]

This study aimed to explore the association between serum albumin (ALB) levels and diabetic retinopathy in patients with type 2 diabetes. In this cross-sectional study, we retrospectively collected clinical data from patients with type 2 diabetes who were admitted to the Endocrinology Department of the Affiliated Hospital of Qingdao University between January 1, 2021, and December 1, 2022. All included patients underwent measurements of serum albumin levels and screening for diabetes-related complications. The association between serum albumin levels and retinopathy was assessed using logistic regression after adjusting for potential confounders. Further, stratified analyses and curve fitting were conducted to delve deeper into the relationship. After inclusion and exclusion criteria were applied, a total of 1947 patients were analyzed. Among these, 982 were male and 965 were female. The mean serum albumin level was 39.86 ± 3.27 g/L. Diabetic retinopathy was present in 41.24% of the patients. After adjusting for potential confounders, we observed a significant inverse association between serum albumin levels and the incidence of retinopathy. Specifically, for every 10 g/L increase in albumin level, the odds of retinopathy decreased (odds ratio [OR] = 0.67; 95% confidence interval [CI] = 0.48–0.94; P = 0.0209).The curve fitting validated the inverse relationship between serum albumin and retinopathy without evidence of non-linearity or threshold saturation effects. Stratified analyses consistently indicated no interaction effects across subgroups. This cross-sectional study identified a significant inverse relationship between serum albumin levels and diabetic retinopathy in patients with type 2 diabetes. However, due to the cross-sectional nature of this study, further prospective studies are warranted to confirm these findings. [ABSTRACT FROM AUTHOR]

This work presents a high energy efficiency onboard hydraulic system for quadruped robot. Firstly, based on the rhythmic motion and mechanical characteristics of leg joints, the energy supply mode that supplies low-pressure oil and high-pressure oil separately for the swing phase and supporting phase is used, and the switch between different oil circuits for each legs is implemented by two digital on-off valves. What's more, to obtain the pressure dynamics characteristics and energy consumption model, the mathematical models is deduced, and the analysis results illustrates that a better rate response can be achieved by adjusting time offset reasonable properly. Finally, the simulations and experiments are conducted to prove that the proposed system shows better energy efficiency compared with that of single pump supply pressure system, meanwhile, the fast dynamic response and the high tracking accuracy are also maintained. [ABSTRACT FROM AUTHOR]

The history of mare volcanism critically informs the thermal evolution of the Moon. However, young volcanic eruptions are poorly constrained by remote observations and limited samples, hindering an understanding of mare eruption flux over time. The Chang'e-5 mission returned the youngest lunar basalts thus far, offering a window into the Moon's late-stage evolution. Here, we investigate the mineralogy and geochemistry of 42 olivine and pyroxene crystals from the Chang'e-5 basalts. We find that almost all of them are normally zoned, suggesting limited magma recharge or shallow-level assimilation. Most olivine grains record a short timescale of cooling. Thermal modeling used to estimate the thickness and volume of the volcanism sampled by Chang'e-5 reveals enhanced magmatic flux ~2 billion years ago, suggesting that while overall lunar volcanic activity may decrease over time, episodic eruptions at the final stage could exhibit above average eruptive fluxes, thus revising models of lunar thermal evolution. This work estimates the eruption volume of the young Chang'e-5 lunar samples using diffusion chronology and thermodynamic simulations, and finds that there was an increase in volcanic eruption flux about 2.0 billion years ago. [ABSTRACT FROM AUTHOR]

Let G be a finite group and H a subgroup of G. We call that H has IC-property if the intersection of H and [H, G] satisfy some conditions. In this paper, we investigate the structure of finite group G under the assumption that some primary subgroups of G have IC-property and obtain some new results. [ABSTRACT FROM AUTHOR]

In this paper, we research on two kinds of cover-avoiding subgroups of a finite group and get some results on p-supersolvable and p-nilpotent properties of a group G. [ABSTRACT FROM AUTHOR]

Secondary ion mass spectrometry (SIMS) zircon U-Pb dating has been widely used to confine the absolute ages of the magmatic or metamorphic events and to distinguish multiple events. Here, a data set consisting of the zircon standards dating data (∼15 000 Plešovice and ∼8 000 Qinghu items) accumulated for more than 8 years using the CAMECA IMS 1280HR of the Institute of Geology and Geophysics, Chinese Academy of Sciences (IGGCAS) is compiled to evaluate the long-term external reproducibility. With Plešovice zircon as the calibration standard and Qinghu zircon as an unknown sample, the analytical uncertainties for single-spot (n = 7 723) and session analyses (n = 691, with more than 7 single spot analyses in one session) are 2.6% and 0.9% (2RSD, relative standard deviation), respectively. It means that single-spot U-Pb dating for a standard-level zircon sample could vary 5.2% at 95% confidence level, while the average value (n > 7) for each session may vary 1.8%. Thus, these values should be considered as the minimum uncertainty when comparing single spot and individual session analysis results for multiple dating works on a certain geological event. [ABSTRACT FROM AUTHOR]

Over the past two decades, a significant number of discoveries of ancient zircon xenocrysts in ocean-floor magmatic rocks have been reported. These findings provide compelling evidence for the presence of ancient continental crust within young oceanic lithosphere. Almost all finds of ancient zircon xenocrysts within oceanic crust are from the Mid-Atlantic Ridge. For other localities, however, similar data are very limited. This report presents the first age determinations (U-Pb, SHRIMP-II) and isotope-geochemical data (oxygen, trace and rare earth elements) for zircon xenocrysts from gabbro-diorites of the Shaka Ridge, in the vicinity of the Shaka fracture zone, near the western end of the Southwest Indian Ridge. The work is based on a study of bottom rock material dredged during expeditionary research on the R/V "Akademik Fedorov" (Russia) in 2016. The U-Pb isotope system of the zircon xenocrysts recorded a crystallization age of ∼2.8 Ga at an upper discordia intercept and an age of ∼600 Ma interpreted as the timing of a superimposed thermal event at a lower discordia intercept. The zircon xenocrysts show geochemical signatures of magmatic origin, i.e., fractionated REE distribution spectra with an increase in chondrite-normalized values from light to heavy REE, positive Ce anomalies and negative Eu anomalies, and high Th/U ratios (0.59–7.77). In discrimination diagrams based on a series of inter-element relationships, zircon compositions fall into the fields of zircons from rocks of continental crust, mostly granitoids. The Li content of the zircons is high (1.8 ppm–50 ppm), adding further evidence to their derivation from rocks of continental crust. During their residence within young oceanic crust, the zircon xenocrysts experienced alterations under the influence of submarine high-temperature hydrothermal fluids, which selectively affected the distribution of trace elements in the zircons and reduced the δ18O values to 1.75‰–3.15‰. The presence of obviously older zircons in Shaka gabbro-diorites clearly demonstrates the presence of ancient continental fragments and their recycling into the mantle at the western end of the Southwest Indian Ridge. [ABSTRACT FROM AUTHOR]

In this paper, we investigated influence of M p -supplemented p-subgroups contained in a normal subgroup on structure of finite groups. We obtained some new criteria for p-supersolvability of finite groups, decided all possible non-Abelian pd-chief factors under our assumption and gave a Frobenius type theorem. Some earlier results on M p -supplemented p-subgroups appear as particular cases. [ABSTRACT FROM AUTHOR]

In this paper, we provide a method to determine when transitive imprimitive groups synchronize a transformation of non-uniform kernel, that is, we give the condition of ⟨ G , α ⟩ being a synchronizing semigroup where G is transitive imprimitive and α is transformation of non-uniform kernel. [ABSTRACT FROM AUTHOR]

We prove that in a finite group G, | a b | = | a | | b | if and only if a b = b a for all elements a, b of G whose orders are factor of the m-th power of different primes, where m is a given integer. [ABSTRACT FROM AUTHOR]

A subgroup S of a group G is called a p-sylowizer of a p-subgroup R in G if S is maximal in G with respect to having R as its Sylow p-subgroup. The main aim of this paper is to investigate the influence of p-sylowizers on the structure of finite groups. We obtained some new characterizations of p-nilpotent and supersolvable groups by the permutability of the p-sylowizers of some p-subgroups. In addition, we determined all p-sylowizers of arbitrary p-subgroups for the supersolvable groups. [ABSTRACT FROM AUTHOR]

Semiconductor photocatalysts has become one of the most attractive technologies in the field of environmental remediation. Titanium dioxide (TiO2) is widely concerned due to the potential applications in the degradation of organic dyes. Nonetheless, the inherent wide band gap of TiO2 has been proved to restrict the photocatalytic activation under visible light, and a variety of strategies have been attempted to develop TiO2 composite catalysts with short band gap compositions, such as carbonaceous nanomaterials. In the recent progress, the present review attaches more importance to the unique morphology and fickle structure of carbonaceous–TiO2 photocatalysts, among which there are sandwich-like structure, foam-like structure, core–shell structure, nanotube, nanorod structure, semi-wrapped structure, etc., and all of them have been demonstrated in this paper. Furthermore, reviews of the enhanced mechanisms, synthesis method and performance comparison of carbonaceous–TiO2 photocatalysts reported in the literature are also suggested and conducted. In brief, this work provides some novel insights for the preparation of TiO2 composites as photocatalysts with excellent performance and contributes to promoting their application in environmental protection issues. [ABSTRACT FROM AUTHOR]

Heat treatment technology is usually used for the processing of metal materials. In this paper, polymer carbon nitride (g-C3N4) is secondarily calcined at 590 °C. A series of nitrogen-doped g-C3N4 are obtained by adjusting the holding time. The doping of nitrogen atoms changes the electronic structure of the catalyst and narrows the band gap. In addition, the escape of ammonia during the secondary calcinations leads to the increase in the specific surface area of the catalyst, which is helpful to enhance the photosensitization effect. Among them, the sample obtained by holding time at 2 h has the highest photogenerated carrier separation efficiency, the largest specific surface area and the best photocatalytic degradation of methylene blue. [ABSTRACT FROM AUTHOR]

It is known that process scaling-up has always been a challenge in biopharmaceutical and food industry. In recent years, newly emerging microscale bioreactors like Ambr15 and Ambr250 have attracted significant attention for that they can provide high throughput and accelerate upstream process development. In this work, we developed the first multiphase Computational Fluid Dynamics (CFD) model for an in-depth characterization of Ambr bioreactor systems. A number of advanced computational methods, including Reynolds stress turbulence model, population balance model, multiple reference frame (MRF), sliding mesh (SM) and user defined functions (UDFs), were integrated for the first time to systematically study the gas-liquid mixing in Ambr250 bioreactor. We provided detailed comparison between MRF and SM method, demonstrated the limitation of MRF for predicting bubble distribution in asymmetric reactors. Characteristics of hydrodynamics, mass transfer, turbulent dissipation and bubble size distribution were predicted from our CFD models and validated by existing experimental data for a variety of operating conditions for both the Ambr15 and Ambr250 bioreactors. The predicted kLa value ranges are 0.18-7.90 h-1 and 2.15-11.52 h-1 for Ambr250 and Ambr15, respectively. This work thus provides a superior framework for the computational modeling of microscale stirred bioreactors. [ABSTRACT FROM AUTHOR]

3D carbon linked by uniform sized nanospheres was successfully prepared by hydrothermal carbonization method. It is found that the increasing reaction temperature and extending reaction times have a similar effect on the morphology of the products, which could evolve from nanospheres to 3D carbon linked by nanospheres or layered structure. The final chemical structure of the products can be switched from a carbon rich in oxygen containing functional groups type to a carbon network of extensive aromatic domain. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride nanosheets (g-CN NS) are an important material with many promising practical applications. However, construction of g-CN NS self-assembled structures with three dimensions (3D) has never been realized. Here, we prepared a self-assembled g-CN NS microgel (SGM) via hydrothermal treatment of g-CN NS in the presence of Ca. The size and microstructure of SGM can be controlled by the concentration of Ca. The obtained SGM also exhibits a temperature response, improved optical properties and high photocatalytic activity. [ABSTRACT FROM AUTHOR]

Let G be a finite group and $$H\le G$$ . In this paper, we investigate the influence of the index of H in $$\langle H, H^{g}\rangle $$ on the structure of G. [ABSTRACT FROM AUTHOR]

LA-ICPMS zircon U-Pb dating has been greatly advanced and widely applied in the past decade because it is a cheap and fast technique. The internal error of LA-ICPMS zircon U-Pb dating can be better than 1%, but reproducibility (accuracy) is relatively poor. In in order to quantitatively assess the accuracy of this technique, zircons from two dioritic rocks, a Mesozoic dioritic microgranular enclave (FS06) and a Neoproterozoic diorite (WC09-32), were dated independently in eight laboratories using SIMS and LA-ICPMS. Results of three SIMS analyses on FS06 and WC09-2 are indistinguishable within error and give a best estimate of the crystallization age of 132.2 and 760.5 Ma (reproducibility is ∼1%, 2RSD), respectively. Zircon U-Pb ages determined by LA-ICPMS in six laboratories vary from 128.3±1.0 to 135.0±0.9 Ma (2SE) for FS06 and from 742.9±3.1 to 777.8±4.7 Ma (2SE) for WC09-32, suggesting a reproducibility of ∼4% (2RSD). Uncertainty produced during LA-ICPMS zircon U-Pb analyses comes from multiple sources, including uncertainty in the isotopic ratio measurements, uncertainty in the fractionation factor calculation using an external standard, uncertainty in the age determination as a result of common lead correction, age uncertainty of the external standards and uncertainty in the data reduction. Result of our study suggests that the uncertainty of LA-ICPMS zircon U-Pb dating is approximately 4% (2RSD). The uncertainty in age determination must be considered in order to interpret LA-ICPMS zircon U-Pb data rationally. [ABSTRACT FROM AUTHOR]

A subgroup H of a finite group G is said to satisfy the $${\Pi}$$ - property in G if every prime dividing $${|G : {\rm N}_{G}(HK \cap L)|}$$ also divides the order of $${(HK \cap L)/K}$$ , for every G-chief factor L/ K of G. The $${\Pi}$$ -property is a subgroup embedding property of arithmetical character introduced in Li (J. Algebra 334:321-337, ) that gathers common properties of many other well-known subgroup embeddings (most of them of normal type) and allows us to glimpse common behaviors to all of them. The aim of this note is to prove that a finite group G is soluble if and only if in G all maximal subgroups satisfy the $${\Pi}$$ -property in G. This is the answer to a question posed by Li (J. Algebra 334:321-337, , Question 5.2). [ABSTRACT FROM AUTHOR]

In- situ seasonal δO measurements of section 236.3-235.6 cm of speleothem HS4, from Qingjiang Valley of the Middle reaches of Yangtze River, China, were performed by an Secondary Ionization Mass Spectrometry (SIMS) with Oka (Chinese primary calcite standard GBW04481) and UWC-3 (international calcite standard from University of Wisconsin). The potential of using SIMS δO measurements to establish speleothem time series has been explored and the differences between conventional and SIMS δO values have been discussed. During a 3-day period, UWC-3 δO has been measured on Cameca IMS 1280 Ion Microprobe Mass Spectrometer against 'Oka' external standard. The measured mean value of UWC-3 ( δO= −17.85‰±0.22‰, 1SD) matches well with its recommended value ( δO=−17.83‰±0.08‰), suggesting that the instrument was stable. The same method applied on HS4 produced δO measurements at seasonal resolution with distinct annual cycles and the total cycle number in agreement with that from Mg/Ca cycles and lamination layer counting of the same section, so it offers an alternative for accessing speleothem time series. However, compared with conventional δO values of HS4, SIMS δO values are more negative by 0.90‰ with larger seasonal variation. The main reasons might come from the micro-cracks, micro-pores or liquid inclusions existing in HS4, and organic materials in the speleothem might be another factor affecting the SIMS δO values, indicating that to obtain reliable speleothem SIMS δO values, both compaction and purity of samples are crucial. [ABSTRACT FROM AUTHOR]

In this paper families of non-nilpotent subgroups covering the non-nilpotent part of a finite group are considered. An $$A_5$$ -free group possessing one of these families is soluble, and soluble groups with this property have Fitting length at most three. A bound on the number of primes dividing the order of the group is also obtained. [ABSTRACT FROM AUTHOR]

Graphene oxide modified porous g-CN (porous g-CN/GO) had been synthesized by means of one-step calcination of cyanamide for efficient photocatalysis under visible light irradiation (λ > 400 nm). We expect that the photocatalytic activity of this hybrid photocatalyst could be enhanced by the efficient visible light absorption due to the porous structure and efficient photo generated charge separation at the heterojunction formed between porous g-CN and GO. Scanning electron microscopy (SEM) images demonstrated that the as prepared photocatalyst is composed of GO and porous g-CN. The UV-vis diffuse reflectance spectrum shows that optical absorption of porous g-CN/GO is more intensive than for pristine g-CN. The enhanced generation of photocurrent under visible light irradiation (λ > 400 nm) is observed for the porous g-CN/GO. The results of photocatalytic experiments reveal that the pseudofirst-order kinetic constant of photocatalytic degradation of methylene blue (MB) using the porous g-CN/GO is 6 times higher than that of pristine g-CN. [ABSTRACT FROM AUTHOR]

In Western Corsica, remnants of pre-batholitic lithological and metamorphic assemblages are preserved as km-scale septa enclosed within Lower Carboniferous to Early Permian plutons. Two groups of septa were recognized: (1) the Argentella and Agriates-Tenda fragments correspond to Neoproterozoic rocks deformed and metamorphosed during the Cadomian-Panafrican orogeny, and (2) the Zicavo, Porto-Vecchio, Solenzara-Fautea, Belgodère, Topiti, and Vignola fragments consist of Variscan metamorphic rocks. The lithological content and the main ductile deformation events for each septum are presented. In the Zicavo, Porto-Vecchio, and Topiti septa, a top-to-the-SW ductile shearing (D1 event) coeval with an amphibolite facies metamorphism is responsible for crustal thickening at ca 360 Ma. This main event was preceded by eclogite and granulite facies metamorphic events preserved as restites within migmatites dated at ca 345-330 Ma. A top-to-the-SE ductile shearing (D2 event) coeval with the crustal melting accommodated the exhumation of the D1 event. In contrast, the Belgodère segment is peculiar as it exhibits a top-to-the-E vergence, although retrogressed high-pressure rocks are also recognized. The pre-Permian fragments are arranged in four NW-SE-striking stripes that define a SW-NE zoning with (1) a Western domain in Topiti, Vignola, Zicavo, Porto-Vecchio, and Solenzara-Fautea; (2) a Neoproterozoic basement with its unconformable Early Paleozoic sedimentary cover in Argentella; (3) an Eastern metamorphic domain in Belgodère; (4) another Neoproterozoic basement with its Upper Paleozoic sedimentary cover in Agriates-Tenda. The Argentella basement is separated from the Western and Eastern domains by two sutures: S1 and S2. The Variscan Corsica represents the Eastern part of the Sardinia-Corsica-Maures segment. The comparison of this segment with other Variscan domains allows us to propose some possible correlations. We argue that the Western domain, Argentella, Belgodère, and Agriates-Tenda domains can be compared with the Southern Variscan belt exposed in French Massif Central-Southern Massif Armoricain, Armorica microblock, Léon block, respectively. [ABSTRACT FROM AUTHOR]

Zircon is the most useful mineral for studies in U-Pb geochronology and Hf and O isotope geochemistry. Matrix effect is a major problem of the microbeam techniques such as SIMS and LA-(MC)-ICPMS. Therefore, external standardization using well-characterized natural zircon standards is fundamental for accurate microbeam measurements. While the isotopic geochronology and geochemistry laboratories equipped with microbeam analytical facilities have been increasingly established in China during the past decade, applications of the isotopic microanalysis are still limited due to shortage of available standards. We report here the Qinghu zircon as a potential new working reference for microbeam analysis of zircon U-Pb age and O-Hf isotopes. This zircon was separated from the Qinghu quartz monzonite from the western Nanling Range, Southeast China. It is fairly homogeneous in U-Pb age and Hf and O isotopes in terms of large amounts of mircobeam measurements by LA-MC-ICPMS and SIMS at the scales of 20-60 μm. SIMS measurements yield consistent Pb/U age within analytical uncertainties with that obtained by ID-TIMS. Precise determinations of O isotopes by IRMS and Hf isotopes by solution MC-ICPMS are in good agreement with the statistical mean of microbeam measurements. We recommend U-Pb age of = 159.5 ± 0.2 Ma (2SE), δO = 5.4‰± 0.2‰ (2SD) and Hf/Hf = 0.283002 ± 0.000004 (2SD) as the best reference values for the Qinghu zircon. [ABSTRACT FROM AUTHOR]

Under study is the influence of the index of H in 〈 H,H〉 for g ∈ G on the structure of a group G, where H is either a second maximal subgroup of G or a Sylow subgroup of G. [ABSTRACT FROM AUTHOR]

Early Yanshanian (Jurassic) granitoids are widespread in the Nanling Range, South China. Whereas large granitic batholiths commonly crop out in the center of the Nanling Range (corresponding geographically to the central and northern parts of Guangdong Province), many small stocks occur in the southern part of Jiangxi Province. Most of the small stocks are associated closely with economically significant rare-metal deposits (W, Sn, Nb, Ta). Here we report the results for biotite granites and two-mica granites from three Yanshanian stocks of the Longyuanba complex. LA-ICPMS U-Pb dating of zircon yields an age of 156.1±2.1 Ma for Xiaomubei biotite granite, and U-Pb zircon dating using SIMS yields an age of 156.7±1.2 Ma for Longyuanba-Chengjiang biotite granite and 156.4±1.3 Ma for Jiangtoudong two-mica granite. Biotite granites are silica-rich (SiO=70%-79%), potassic (KO/NaO>1.9), and peraluminous (ASI=1.05-1.33). Associated samples are invariably enriched in Rb, Th, Pb and LREE, yet depleted in Ba, Nb, Sr, P and Ti, and their REE pattern shows a large fractionation between LREE and HREE ((La/Yb)=10.7-13.5) and a pronounced Eu negative anomaly ( δEu=0.28-0.41). Two-mica granite samples are also silica-rich (SiO=75%-79%), potassic (KO/NaO>1.2), and peraluminous (ASI=1.09-1.17). However, in contrast to the biotite granites, they are more enriched in Rb, Th, Pb and extremely depleted in Ba, Nb, Sr, P and Ti, and exhibit nearly flat ((La/Yb)=0.75-1.08) chondrite-normalized REE patterns characterized by strong Eu depletion ( δEu=0.02-0.04) and clear tetrad effect (TE=1.10-1.14). Biotite granites and two-mica granties have comparable Nd isotopic signatures, and their ɛNd( t) are concentrated in the −13.0 to −9.6 and −11.5 to −7.7 respectively. Their zircon Hf-O isotopes of both also show similarity (biotite granites: ɛHf( t)=−10.8-−7.9, δO=7.98‰-8.89‰ and ɛHf( t)= −13.8 to −9.1, δO=8.31‰-10.08‰; two-mica granites: ɛHf( t)=−11.3 to −8.0, δO=7.91‰-9.77‰). The results show that both biotite and two-mica granites were derived mainly from sedimentary source rocks with a minor contribution from mantle-derived materials. In spite of some S-type characteristics, the biotite granites were formed by fractional crystallization of I-type magma and assimilation of peraluminous sedimentary rocks during their ascent to the surface. Therefore, they belong to highly fractionated I-type granites. Two-mica granites exhibit a tetrad effect in their REE patterns, but share the same isotopic features with the biotite granites, suggesting that they are highly fractionated I-type granites as well. Their Lanthanide tetrad effects may be attributed to the hydrothermal alteration by magmatic fluids that have suffered degassing at late stages. Granitic magmas undergoing fractional crystallization and wall-rock assilimation can generate highly evolved granites with no REE tetrad effect in the uni-phase system. However, in the late-stage of magmatic evolution in the multi-phase system (i.e., magmatic-hydrothermal system), these magmas also can lead to the highly evolved granites exhibiting mew-shaped REE pattern characterized by tetrad effect as the consequence of melt-fluid and fluid-vapor fractionation, and the resultant autometasomatism. We thus suggest that the REE pattern exhibiting tetrad effect feature is an important indicator of rare metal mineralization in the early Yanshanian time in southern China, implying the metamorphism of the ore fluid. [ABSTRACT FROM AUTHOR]

Titanite is an ideal mineral for U-Pb isotopic dating because of its relatively high U, Th and Pb contents. Here, we developed a technique for U-Pb dating of titanite using the 193 nm ArF laser-ablation system and Agilent 7500a Q-ICP-MS. Standards of titanite (BLR-1 and OLT-1) and zircon (91500 and GJ-1) were dated using single spot and line raster scan analytical methods. To check the matrix effect, titanite (BLR-1) and zircon (91500) standards were analyzed as the external standards. The weighted mean Pb/U ages of OLT-1 titanite are 1015±5 Ma (2 σ, n=24) and 1017±6 Ma (2 σ, n=24) by single spot and line raster scan analyses, respectively, using BLR-1 titanite as the external standard. These ages are consistent with its reference age of about 1014 Ma. However, using 91500 zircon as the external standard, the weighted mean Pb/U ages are 917±4 Ma (2 σ, n=24) and 927±5 Ma (2 σ, n=24) for BLR-1 titanite, and 891±4 Ma (2 σ, n=24) and 901±5 Ma (2 σ, n=24) for OLT-1 titanite by single spot and line raster scan analyses, respectively. It is evident that these ages are ∼12% younger than their reference values. Our results reveal that significant matrix effect does exist between different kinds of minerals during LA-ICPMS U-Pb age determination, whereas it is insignificant between same minerals. Therefore, same mineral must be used as the external standard for fractionation corrections during in situ LA-ICPMS U-Pb age analysis. In addition, we determined U-Pb ages for titanites from the Early Cretaceous Fangshan pluton, which indicates a rapid cooling history of this pluton. [ABSTRACT FROM AUTHOR]

We call H an SΦ-supplemented subgroup of a finite group G if there exists a subnormal subgroup T of G such that G = HT and H ∩ T ≤ Φ( H), where Φ( H) is the Frattini subgroup of H. In this paper, we characterize the p-nilpotency and supersolubility of a finite group G under the assumption that every subgroup of a Sylow p-subgroup of G with given order is SΦ-supplemented in G: Some results about formations are also obtained. [ABSTRACT FROM AUTHOR]

We introduce and study the minimal inner-Σ-Ω-groups and the minimal outer-Σ-℧-groups. Then we give some applications and obtain some interesting results, including characterizations of nilpotent, supersolvable, solvable, and p-closed groups in terms of the join of two conjugate cyclic subgroups having the same property. [ABSTRACT FROM AUTHOR]

In this paper, we introduce the concept of weakly s-semipermutable subgroups. Let G be a finite group. Using the condition that the minimal subgroups or subgroups of order p of a given Sylow p-subgroup of G are weakly s-semipermutable in G, we give a criterion for p-nilpotency of G and get some results about formation. [ABSTRACT FROM AUTHOR]

In this paper, we characterize the nilpotency and supersolvability of a finite group G by assuming some subgroups of prime power order have the semi cover-avoiding property in G. Some earlier results are generalized. [ABSTRACT FROM AUTHOR]

subgroup H of a group G is weakly normal in G if H ≤ N( H) implies that g ∈ N( H). In this paper, we shall obtain some characterizations about the supersolvability and nilpotency of G by assuming that some subgroups of prime power order of G are weakly normal in G. [ABSTRACT FROM AUTHOR]

Let G be a finite p-group. If the order of the derived subgroup of each proper subgroup of G divides p, G is called a D-group. In this paper, we give a characterization of all D-groups. This is an answer to a question introduced by Berkovich. [ABSTRACT FROM AUTHOR]

Although a number of petrographic observations and isotopic data suggest that magma mixing is common in genesis of many granite plutons, it is still controversial whether the mantle-derived magmas were involved in granites. We carried out in this study a systematic analysis of in situ zircon Hf-O isotopes for three early Yanshanian intrusions dated at ca. 160 Ma from the Nanling Range of Southeast China. The Qinghu monzonite has very homogeneous zircon Hf-O isotopic compositions, ɛ Hf( t)=11.6±0.3 and δ 18O=5.4%±0.3‰ In combination with whole-rock geochemical and Sr-Nd isotopic data, the parental magma of the Qinghu monzonite were likely derived from the partial melting of recently-metasomatized, phlogopite-bearing lithospheric mantle without appreciable crustal contamination. The Lisong and Fogang granites and the mafic microgranular enclaves (MME) within the Lisong granites have a wide range of zircon Hf-O isotopic compositions, with Hf and O isotopes being negatively correlated within each pluton. The Lisong MMEs were crystallized from a mantle-derived magma, similar to the parental magma of the Qinghu monzonite, with small amount of crustal assimilation. The Lisong and Fogang granites were formed by reworking of meta-sedimentary materials by mantle-derived magmas and mixing of the mantle- and sediment-derived melts to varying degrees. It is thus concluded that these two Yanshanian granites in the Nanling Range were formed associated with growth and differentiation of continental crust. [ABSTRACT FROM AUTHOR]

Determination of the age of the Precambrian-Cambrian boundary is critical in understanding early evolution of life on Earth. SIMS U-Pb zircon analyses of the Bed 5 tuff layer of the Meishucun section were carried out closely following the guidance of cathodoluminescence images, and the majority of analyses were conducted on the oscillatory zircon grains. Thirteen measurements yield a highly reliable Concordia U-Pb age of 536.7 ±3.9 Ma for the Bed 5 horizon. A grand mean of 206Pb/238U age of 535.2±1.7 Ma (MSWD = 0.53) is calculated based on 13 concordant SIMS measurements of this study and 4 nano-SIMS measurements of Sawaki et al., which is the best estimate of the deposition age of the tuff layer within Bed 5 in the Meishucun section. This age has provided a robust age constraint on the significant Precambrian-Cambrian boundary strata in southern China, which independently suggested the placement of the Precambrian-Cambrian boundary at the bottom of the Xiaowaitoushan Member (Marker A). [ABSTRACT FROM AUTHOR]

A garnet-bearing tonalitic porphyry from the Achiq Kol area, northeast Tibetan Plateau has been dated by SHRIMP U-Pb zircon techniques and gives a Late Triassic age of 213 ± 3 Ma. The porphyry contains phenocrysts of Ca-rich, Mn-poor garnet (CaO > 5 wt%; MnO < 3 wt%), Al-rich hornblende (Al2O3 ~ 15.9 wt%), plagioclase and quartz, and pressure estimates for hornblende enclosing the garnet phenocrysts yield values of 8–10 kbar, indicating a minimum pressure for the garnet. The rock has SiO2 of 60–63 wt%, low MgO (<2.0 wt%), K2O (<1.3 wt%), but high Al2O3 (>17 wt%) contents, and is metaluminous to slightly peraluminous (ACNK = 0.89–1.05). The rock samples are enriched in LILE and LREE but depleted in Nb and Ti, showing typical features of subduction-related magmas. The relatively high Sr/Y (~38) ratios and low HREE (Yb < 0.8 ppm) contents suggest that garnet is a residual phase, while suppressed crystallization of plagioclase and lack of negative Eu anomalies indicate a high water fugacity in the magma. Nd–Sr isotope compositions of the rock (εNdT = −1.38 to −2.33; 87Sr/86Sri = 0.7065–0.7067) suggest that both mantle- and crust-derived materials were involved in the petrogenesis, which is consistent with the reverse compositional zoning of plagioclase, interpreted to indicate magma mixing. Both garnet phenocrysts and their ilmenite inclusions contain low MgO contents which, in combination with the oxygen isotope composition of garnet separates (+6.23‰), suggests that these minerals formed in a lower crust-derived felsic melt probably in the MASH zone. Although the rock samples are similar to adakitic rocks in many aspects, their moderate Sr contents (<260 ppm) and La/Yb ratios (mostly 16–21) are significantly lower than those of adakitic rocks. Because of high partition coefficients for Sr and LREE, fractionation of apatite at an early stage in the evolution of the magma may have effectively decreased both Sr and LREE in the residual melt. It is suggested that extensive crystallization of apatite as an early phase may prevent some arc magmas from evolving into adakitic rocks even under high water fugacity. [ABSTRACT FROM AUTHOR]

An investigation of the copolymerization of allyl glycidyl ether (AGE) with methyl acrylate (MA) was performed in the presence of benzyl imidazole-1-carbodithioate (BICDT) on the thermal initiation condition. Results showed that the process has good characteristics of living free radical polymerization, i.e. the molecular weight of the obtained polymer increases linearly with monomer conversion, molecular weight distribution is very narrow, and a linear relationship between ln([M]0/[M]) and polymerization time is found. The copolymer structure containing epoxy groups was demonstrated from the 1H nuclear magnetic resonance (1H NMR) spectrum. It was found that the content of AGE in the copolymer increases with the increase in monomer conversion and molar faction of the AGE in the monomer feed. However, the polymerization could slow down when the fraction of AGE increases in the monomer feed. Taking advantage of living polymerization character, functional block copolymers PSt- b-P (MA- co-AGE) were prepared in the presence of PSt RAFT agent. [ABSTRACT FROM AUTHOR]

Early Yanshanian (Jurassic) granitoids are widespread in the Nanling Range of South China, and are associated with numerous non-ferrous and rare metal mineral deposits. These granitoids consist mainly of slightly peraluminous biotite monzogranites and K-feldspar granites that are closely associated in time and space with subordinate amphibole-bearing granites and muscovite- and garnet-bearing granites. In most previous studies, the biotite-bearing granites were classified as crustal transformation-type (corresponding to the S-type) granites which were interpreted to be derived from the regional Paleoproterozoic meta-sedimentary rocks. In this paper, we re-analyze the geochemical characteristics of a number of representative Early Yanshanian Nanling granitoids. There exists a clear negative correlation between SiO2 and P2O5 for the studied granitoids. The Early Yanshanian Nanling granitoid suites (including amphibole-bearing granodiorites→biotite monzogranites→K-feldspar granites→two-mica (muscovite) granites) are metaluminous to slightly peraluminous I-type or fractionated I-type granites. They were derived predominantly from Proterozoic igneous protoliths. The juvenile crust and/or newly mantle-derived materials might also have been involved in some of these granites. In addition, the I- and fractionated I-type granites are closely associated in time and space with minor amount of A-type felsic and mafic volcanic and intrusive rocks as well as alkaline rocks. All these rocks constitute a typical assemblage of anorogenic, intraplate magmatism, suggesting a dominant lithospheric extensional regime for the Nanling Range and neighboring region during the Early Yanshanian period. [ABSTRACT FROM AUTHOR]

Neoproterozoic magmatic rocks are widespread in the western margin of the Yangtze block, and their origin and genesis have significant implications for understanding the evolution of the Rodinia super-continent. However, there are currently two opposing interpretations for their petrogenesis and tectonic setting: mantle plume-related and island arc origin. To further verify these two competing models, SHRIMP U-Pb zircon age determinations and geochemical and Nd-Hf isotopic analyses are conducted on the mafic dykes in the Kangdian Rift, western Sichuan. U-Pb dating suggests that these mafic dykes were emplaced at 780–760 Ma, spatially and temporally coeval with the Kangding granitoid complex. The parental magmas of these dykes were derived from a depleted asthenosphere mantle source likely triggered by an anomalously-hot mantle plume. Despite some arc-geochemical features caused by variable degrees of contamination of young island arc crust during magma ascending and emplacement, they show general geochemical and Nd-Hf isotopic features similar to those of the intraplate basalts. Our results support the reconstruction model of Rodinia in which the South China block was located between Australia and Laurentia. [ABSTRACT FROM AUTHOR]

High-precision major element and Hf isotope data are reported for the Neoproterozoic Suxiong volcanic rocks along the western margin of the Yangtze Block. These volcanic rocks have variable ϵHf(T) values and Fe/Mn ratios. The relatively primitive basalts have high Fe/Mn ratios and high Hf-Nd isotopic compositions, indicating that they were generated by partial melting of garnet clinopyroxene in mantle plume at high pressure. Thus, the Suxiong basalts are genetically related to the proposed Neoproterozoic super-plume. On the contrary, a few differentiated basalts have low Fe/Mn ratios and low Hf-Nd isotopic compositions. They are likely to experience assimilation-fractional crystallization process. The Suxiong rhyolites have consistent Hf and Nd model ages of 1.3–1.4 Ga. They are likely generated by shallow dehydration melting of pre-existing young arc igneous rocks associated with the basaltic underplating/intrusion in a continental rift. [ABSTRACT FROM AUTHOR]

We study the problem concerning the influence of indices of maximal subgroups of a simple group on the structure of a group. We obtain a characterization property of all finite simple groups. [ABSTRACT FROM AUTHOR]

We introduce the notion of θ-pair of a proper subgroup of a finite group and give necessary and sufficient conditions for supersolvability and nilpotence of a finite group. As application, we give a proof to a recent open problem of Skiba in the unsolved problems in group theory. [ABSTRACT FROM AUTHOR]

States the third summary report of ODP Leg 184 to the South China Sea (SCS) discusses the evolution of the East Asian monsoon and the SCS basin. Adoption of a multi-proxy approach of geochemistry, micropaleontology, pollen and other analyses; Paleo-climate events; Stages in the development of the East and South Asian monsoons, including the enhanced winter monsoon; Monsoon variability and other features of the low latitude ocean; The hemipelagic Oligocene sediments that suggest deep water environments existed during the early seafloor spreading stage of the SCS basin; The four major unconformities; Diagenetic features in upper Oligocene deposits pointing to tectonic events in the region; Comparison of lithologies and sedimentation rates; Conclusion that the differences in sedimentary environments between the southern and northern SCS were established by -3 Ma.

Discusses the Zircon SHRIMP uranium-lead dating for the Cangshuipu volcanic rocks and its implications for the lower boundary age of the Nanhua strata in South China. Occurrence of the continental volcanic rocks and volcaniclastic sedimentary conglomerates of the Cangshuipu Formulation in Yiyang of Hunan Province; Configuration of the strata in the Yiyang region; Representation of the lower boundary with a younger age than previously reported.

This paper has reported the first application of 40Ar/39 Ar dating to orthoclase from Qitianling granite. The resultant plateau ages yielded by three orthoclase specimens 2KL-17, 99LQ-2 and 2KL-31 (Note: The last one was taken from the part of granite which had been attributed to Cailing super-unit of the Indosinian Period by the former researchers) collected from the said granite are (139.57±2.79) Ma, (140.55±2.81) Ma and (144.91±2.90) Ma respectively. The above-mentioned ages represent the closed 40Ar/39 Ar age of the orthoclase. The consistency in age dating results, the similarity in geochemical characteristics and rock textures, and the NW-SE orientation of orthoclase phenocrysts almost throughout the granite, provide evidence for the intimate relationship between the Furong super-unit and the Cailing super-unit that form the main part of the granite, suggesting that they are products of comagmatic conjugate differentiation during the Late Jurassic. This paper also makes a comparison between the Qitianling granite and the Qianlishan granite. [ABSTRACT FROM AUTHOR]

SHRIMP U-Pb zircon age, geochemical and Nd isotopic data are reported for the Neo-proterozoic Guandaoshan pluton in the Yanbian region, SW Sichuan. This pluton is of typical I-type granite and emplaced at (857 ± 13) Ma. Geochemical and Nd isotopic characters suggest that the pluton was generated by partial melting of pre-existing, young (late Mesoproterozoic to early Neo-proterozoic) low-K tholeiitic protolith within an intraplate anorogenic setting. The Guandaoshan pluton probably records the earliest magmatism induced by the proposed ca. 860–750 Ma mantle superplume beneath the supercontinent Rodinia. [ABSTRACT FROM AUTHOR]