Original sedimentary manganese(Mn)deposits and supergene Mn ores are important Mn resources in China.However,the geochemical information from Chinese supergene Mn ores is scarce,and the relationship between sedimentar...Original sedimentary manganese(Mn)deposits and supergene Mn ores are important Mn resources in China.However,the geochemical information from Chinese supergene Mn ores is scarce,and the relationship between sedimentary Mn deposits and supergene Mn ores is ambiguous.In this study,we collected the original Mn-bearing dolomitic sandstones(ZK20-3 drillcore)and supergene Mn ores(Longmen Section)from eastern Hebei,North China for systematic petrographic,mineralogical and geochemical analyses.Our new data help us to figure out the transformation from original Mn-bearing deposits to supergene ores.The main minerals of original Mn-bearing dolomitic sandstones are quartz and feldspar,with minor muscovite,dolomite,rhodochrosite,ankerite,and kutnohorite.Supergene Mn-oxide ores only emerged in the middle part of the Longmen(LM)Section,and mainly contain quartz,pyrolusite,cryptomelane,todorokite and occasional dolomite.The possible transformation sequence of Mn minerals is:kutnohorite/rhodochrosite→pyrolusite(Ⅰ)→cryptomelane(todorokite)→todorokite(cryptomelane)→pyrolusite(Ⅱ).For Mn-oxide ores,Fe,Na and Si are enriched but Al,Ca,Mg and K are depleted with the enrichment of Mn.For original and supergene ores,the total rare earth element+ytterbium(∑REY)contents range from 105.68×10^(-6)to 250.56×10^(-6)and from 18.08×10^(-6)to 176.60×10^(-6),respectively.Original Mn ores have similar slightly LREE-enriched patterns,but the purer Mn-oxide ore shows a HREE-enriched pattern.In the middle part of the LM Section,positive Ce anomalies in Mn-oxide ores indicate the precipitation of Ce-bearing minerals.It implies the existence of geochemical barriers,which changed p H and Eh values due to the long-time influence of groundwater.展开更多
Metal-organic frameworks(MOFs),with their ultrahigh specific surface area,uniformly distributed pores,and tunable structures,are promising candidates for next-generation active electrode materials in lithium-ion batte...Metal-organic frameworks(MOFs),with their ultrahigh specific surface area,uniformly distributed pores,and tunable structures,are promising candidates for next-generation active electrode materials in lithium-ion batteries(LIBs).However,their application is hindered by poor cycling stability due to structural collapse during charge-discharge cycles.To address this issue,we developed an alloy and multi-solvent thermal method strategy to synthesize Co/Zn bimetallic MOFs based on Naphthalenetetracarboxylic acid(NTCA).The resulting petal-like Co/Zn-NTCA MOF demonstrates outstanding electrochemical performance.The incorporation of zinc ions not only significantly enhances cycling stability but also markedly increases the specific capacity of the anode material.At a current density of 200 mA·g^(-1),the Co/Zn(2:1)-NTCA MOF demonstrated an impressive reversible capacity of 956 mA·h·g^(-1) after 150 cycles.Even after 500 cycles,the specific capacity of the electrode remained high,with a value of 438 mA·h·g^(-1) at a current density of 1000 A·g^(-1).展开更多
Burmanniaceae is one major group within the monocot order Dioscoreales that has not had its plastome sequenced.Members of Burmanniaceae are mostly achlorophyllous,although the genus Burmannia also includes autotrophs....Burmanniaceae is one major group within the monocot order Dioscoreales that has not had its plastome sequenced.Members of Burmanniaceae are mostly achlorophyllous,although the genus Burmannia also includes autotrophs.Here,we report sequencing and analysis of the first Burmanniaceae plastid genome from Burmannia disticha L..This plastome is 157,480 bp and was assembled as a circular sequence with the typical quadripartite structure of plant plastid genomes.This plastome has a regular number of potentially functional genes with a total of 111,including 78 protein coding genes,4 ribosomal RNA(rRNA) genes,and 29 tRNA genes.The ratio of the total length of genic:intergenic DNA is 1.58:1,and the mean length of intergenic regions is 398 bp,the longest being 1918 bp.The overall GC content of the B.disticha plastome is 34.90%,and the IR regions in B.disticha are more GC rich(39.50%) than the LSC(32.30%) and SSC(28.80%) regions.Phylogenetic analysis of protein-coding sequences from plastomes of related species in the order Dioscoreales support a clade comprising Burmanniaceae and Dioscoreaceae.This phylogenetic placement is congruent with previous findings based on nuclear and mitochondrial evidence.展开更多
The photocatalytic conversion of biomass into high-value chemicals,coupled with simultaneous hydrogen(H_(2))evolution,leveraging the electrons and holes generated by solar energy,holds great promise for addressing ene...The photocatalytic conversion of biomass into high-value chemicals,coupled with simultaneous hydrogen(H_(2))evolution,leveraging the electrons and holes generated by solar energy,holds great promise for addressing energy demands.In this study,we constructed a dual functional photocatalytic system formed by NiS loaded on Ni doped two-dimensional(2D)CdS nanosheet(NiS/Ni-CdSNS)heterostructure for visible-light-driven H_(2)evolution and ethanol oxidation to acetaldehyde.Remarkably,the 2D NiS/NiCdSNS exhibited significant activity and selectivity in both photocatalytic H_(2)evolution and ethanol oxidation,achieving yields of 7.98 mmol g^(-1)h^(-1)for H_(2)and 7.33 mmol g^(-1)h^(-1)for acetaldehyde.The heterogeneous interface of the composite facilitated efficient charge separation,while NiS provided abundant sites for proton reduction,thereby promoting the overall dual-functional photocatalytic activity.Density functional theory calculations further reveal that both Ni doping and NiS loading can reduce the reaction energy barrier of ethanol oxidation of free radicals,and NiS/Ni-CdSNS composite materials exhibit stronger ethanol C-H activation ability to generate key intermediate·CH(OH)CH_(3)on the surface.This work serves as a valuable guide for the rational design of efficient dual functional photocatalytic systems that combine H_(2)evolution with the selective conversion of organic compounds into high-value chemicals.展开更多
Solar-driven hydrogen(H_(2))evolution and contaminant degradation offer a promising pathway to address the global energy and environmental crisis.However,the inadequate separation of carriers and light absorption rema...Solar-driven hydrogen(H_(2))evolution and contaminant degradation offer a promising pathway to address the global energy and environmental crisis.However,the inadequate separation of carriers and light absorption remain significant challenges in the advancement of photocatalysis.In this work,a general in situ ion exchange strategy has been employed to integrate palladium single atoms(Pd SAs)into hollow cadmium sulfide(CdS-H)spheres,creating a multifunctional photocatalyst for both photocatalytic H_(2)evolution and organic degradation.The hollow structure enhances light refraction,and Pd SAs act as charge transfer channels,leading to a significant enhancement in the spatial separation efficiency of photocatalytic charge carries pairs and light utilization in the synthesized Pd SAs/CdS-H.Consequently,the optimized 0.3Pd SAs/CdS-H demonstrates an exceptional photocatalytic H_(2) evolution efficiency of 22.23 mmol h^(-1)g^(-1)and an organic pollutant removal rate of 99.2%.Experimental analyses and density functional theory calculations reveal that the Pd SAs lower the work function of CdS-H and enhance the interfacial charge transport,which is crucial for improving photocatalytic performance.Moreover,both superoxide radicals and holes contribute to the removal of organic dyes,as directly confirmed by in situ radical capture experiments.Based on these characterization results,the photocatalytic mechanism for photocatalytic H_(2) evolution and pollutant degradation is proposed,respectively.This work establishes a dual-functional photocatalyst design strategy for sustainable energy generation and environmental remediation.展开更多
The development of reliable fusion energy is one of the most important challenges in this century.The accelerated degradation of structural materials in fusion reactors caused by neutron irradiation would cause severe...The development of reliable fusion energy is one of the most important challenges in this century.The accelerated degradation of structural materials in fusion reactors caused by neutron irradiation would cause severe problems.Due to the lack of suitable fusion neutron testing facilities,we have to rely on ion irradiation experiments to test candidate materials in fusion reactors.Moreover,fusion neutron irradiation effects are accompanied by the simultaneous transmutation production of helium and hydrogen.One important method to study the He-H synergistic effects in materials is multiple simultaneous ion beams(MSIB)irradiation that has been studied for decades.To date,there is no convincing conclusion on these He-H synergistic effects among these experiments.Recently,a multiple ion beam in-situ transmission electron microscopy(TEM)analysis facility was developed in Xiamen University(XIAMEN facility),which is the first triple beam system and the only in-running in-situ irradiation facility with TEM in China.In this work,we conducted the first high-temperature triple simultaneous ion beams irradiation experiment with TEM observation using the XIAMEN facility.The responses to in-situ triple-ion beams irradiation in austenitic steel 304L SS and ferritic/martensitic steel CLF-1 were studied and compared with the results in dual-and single-ion beam(s)irradiated steels.Synergistic effects were observed in MSIB irradiated steels.Helium was found to be critical for cavity formation,while hydrogen has strong synergistic effect on increasing swelling.展开更多
Impact of amplified spontaneous emission(ASE)noise on the stimulated Raman scattering(SRS)threshold of highpower fiber amplifiers is demonstrated numerically through a spectral evolution approach.The simulation result...Impact of amplified spontaneous emission(ASE)noise on the stimulated Raman scattering(SRS)threshold of highpower fiber amplifiers is demonstrated numerically through a spectral evolution approach.The simulation results confirm that ASE noise in the Raman wavelength band could reduce the SRS threshold of high-power fiber amplifiers significantly.As for ASE noise originated the main amplifier,it becomes stronger and reduces the SRS threshold at shorter operation wavelength below 1052 nm.As for ASE noise originated from the seed laser,it reduces the SRS threshold at different operation wavelength under the condition that the Raman ratio is over-90 dB in the seed laser.The theoretical method and results in this work could provide a well reference to extend the operation wavelength of high-power fiber lasers.展开更多
Macrophages play critical roles in renal fibrosis.However,macrophages exhibit ontogenic and functional heterogeneities,and which population of macrophages contributes to renal fibrosis and the underlying mechanisms re...Macrophages play critical roles in renal fibrosis.However,macrophages exhibit ontogenic and functional heterogeneities,and which population of macrophages contributes to renal fibrosis and the underlying mechanisms remain unclear.In this study,we genetically targeted Notch signaling by disrupting the transcription factor recombination signal binding protein-JK(RBP-J),to reveal its role in regulation of macrophages during the unilateral ureteral obstruction(UUO)-induced murine renal fibrosis.Myeloid-specific disruption of RBP-J attenuated renal fibrosis with reduced extracellular matrix deposition and myofibroblast activation,as well as attenuated epithelial-mesenchymal transition,likely owing to the reduced expression of TGF-β.Mean while,RBP-J deletion significantly hampered macrophage infiltration and activation in fibrotic kidney,although their proliferation appeared unaltered.By using macrophage clearance experiment,we found that kidney resident macrophages made negligible contribution,but bone marrow(BM)-derived macrophages played a major role in renal fibrogenesis.Further mechanistic analyses showed that Notch blockade reduced monocyte emigration from BM by down-regulating CCR2 expression.Finally,we found that myeloid-specific Notch activation aggravated renal fibrosis,which was mediated by CCR2^+macrophages infiltration.In summary,our data have unveiled that myeloid-specific targeting of Notch could ameliorate renal fibrosis by regulating BM-derived macrophages recruitment and activation,providing a novel strategy for intervention of this disease.展开更多
An all-fiberized and narrow-bandwidth master oscillator power amplification(MOPA) system with record output power of 4 kW level and slope efficiency of 78% is demonstrated. Tandem pumping strategy is tentatively intro...An all-fiberized and narrow-bandwidth master oscillator power amplification(MOPA) system with record output power of 4 kW level and slope efficiency of 78% is demonstrated. Tandem pumping strategy is tentatively introduced into the narrow-bandwidth MOPA system for thermally induced mode instability(TMI) suppression. The stimulated Brillouin scattering(SBS) effect is balanced by simply using one-stage phase modulation technique. With different phase modulation signals, SBS limited output powers of 336 W, 1.2 kW and 3.94 kW are respectively achieved with spectral bandwidths accounting for 90% power of ～0.025, 0.17 and ～0.89 nm. Compared with our previous 976 nm pumping system, TMI threshold is overall boosted to be >5 times in which tandem pumping increases the TMI threshold of >3times. The beam quality(M～2 factor) of the output laser is well within 1.5 below the TMI threshold while it is ultimately saturated to be 1.86 with the influence of TMI at maximal output power. Except for SBS and TMI, stimulated Raman scattering(SRS) effect will be another challenge for further power scaling. In such a high power MOPA system, multidetrimental effects(SBS, SRS and TMI) will coexist and may be mutual-coupled, which could provide a well platform for further comprehensively investigating and optimizing the high power, narrow-bandwidth fiber amplifiers.展开更多
High-power mode-programmable orbital angular momentum(OAM)beams have received substantial attention in recent years.They are widely used in optical communication,nonlinear frequency conversion,and laser processing.To ...High-power mode-programmable orbital angular momentum(OAM)beams have received substantial attention in recent years.They are widely used in optical communication,nonlinear frequency conversion,and laser processing.To overcome the power limitation of a single beam,coherent beam combining(CBC)of laser arrays is used.However,in specific CBC systems used to generate structured light with a complex wavefront,eliminating phase noise and realizing flexible phase modulation proved to be difficult challenges.In this paper,we propose and demonstrate a two-stage phase control method that can generate OAM beams with different topological charges from a CBC system.During the phase control process,the phase errors are preliminarily compensated by a deep-learning(DL)network,and further eliminated by an optimization algorithm.Moreover,by modulating the expected relative phase vector and cost function,all-electronic flexible programmable switching of the OAM mode is realized.Results indicate that the proposed method combines the characteristics of DL for undesired convergent phase avoidance and the advantages of the optimization algorithm for accuracy improvement,thereby ensuring the high mode purity of the generated OAM beams.This work could provide a valuable reference for future implementation of high-power,fast switchable structured light generation and manipulation.展开更多
We report on the high-power amplification of a 1064 nm linearly polarized laser in an all-fiber polarizationmaintained master oscillator power amplifier,which can operate at an output power level of 1.3 kW.The beam qu...We report on the high-power amplification of a 1064 nm linearly polarized laser in an all-fiber polarizationmaintained master oscillator power amplifier,which can operate at an output power level of 1.3 kW.The beam quality(M^2) was measured to be <1.2 at full power operation.The polarization extinction rate of the fiber amplifier was measured to be above 94% before mode instabilities(MIs) set in,which reduced to about 90% after the onset of MI.The power scaling capability of strategies for suppressing MI is analyzed based on a semianalytical model,the theoretical results of which agree with the experimental results.It shows that mitigating MI by coiling the gain fiber is an effective and practical method in standard double-cladding large mode area fiber,and,by tight coiling of the gain fiber to the radius of 5.5 cm,the MI threshold can be increased to three times higher than that without coiling or loose coiling.Experimental studies have been carried out to verify the idea,which has proved that MI was suppressed successfully in the amplifier by proper coiling.展开更多
The Middle Miocene Climate Transition(MMCT,~14 Ma)is the largest cooling event in the Cenozoic“Coolhouse”,which significantly impacts the global chemical weathering pattern.In this paper,the responses of the MMCT gl...The Middle Miocene Climate Transition(MMCT,~14 Ma)is the largest cooling event in the Cenozoic“Coolhouse”,which significantly impacts the global chemical weathering pattern.In this paper,the responses of the MMCT global cooling event in the deep South China Sea were studied by clay mineral assemblages analysis of the oceanic red beds(ORB)at International Ocean Discovery Program(IODP)Expedition 368 Site U1502.The results show that the clay mineral assemblages of the ORB at Site U1502 are mainly composed of smectite(56–88%),illite(7–29%),and kaolinite(6–20%),without chlorite.The contents of these clay minerals and illite crystallinity show a four-stage variation pattern during early-middle Miocene(22.8–10.8 Ma).Smectite decreased from average 81%during 22.8–16.2 Ma and 16.2–14.4 Ma to average 67%during 13.8–10.8 Ma,with a rapid decrease of~14%during 14.4–13.8 Ma.On the contrary,illite and kaolinite increased rapidly by~8%and~6%,respectively,during 14.4–13.8 Ma.Illite crystallinity increased from average 0.18°Δ2θduring 22.8–16.2 Ma to average 0.19°Δ2θduring 16.2–14.4 Ma,and then decreased rapidly by~0.02°Δ2θduring 14.4–13.8 Ma.The provenance analysis of clay minerals shows that illite and kaolinite mainly originated from South China landmass due to physical erosion,while smectite mainly came from the Luzon arc as the product of chemical weathering.Therefore,smectite/illite ratio and illite crystallinity are used as proxies of chemical weathering intensity in the early-middle Miocene.High values of the ratio and the crystallinity represent the enhanced chemical weathering,whereas low values indicate the weakened chemical weathering or the strengthened physical erosion process.The smectite/illite ratio and illite crystallinity both decreased rapidly during 14.4–13.8 Ma,indicating the chemical weathering in the surrounding area of the South China Sea weakened rapidly,which we believe is the result of the MMCT event forcing.In addition,their values increased slightly during 16.2–14.4 Ma,which is in response to the relatively enhanced chemical weathering during the Middle Miocene Climate Optimum(MMCO).The variation pattern of clay mineral assemblages of the early-middle Miocene ORB in the South China Sea and its rapid transformation during the MMCT reveal that the Cenozoic cooling played a specific role in controlling the chemical weathering of the Earth’s surface.展开更多
In this paper,we have experimentally demonstrated a high-power and high-brightness narrow-linewidth fiber amplifier seeded by an optimized fiber oscillator.In order to improve the temporal stability,the fiber oscillat...In this paper,we have experimentally demonstrated a high-power and high-brightness narrow-linewidth fiber amplifier seeded by an optimized fiber oscillator.In order to improve the temporal stability,the fiber oscillator consists of a composite fiber Bragg grating-based cavity with an external feedback structure.By optimizing the forward and backward pumping ratio,the nonlinear effects and stimulated Raman scattering-induced mode distortion of the fiber amplifier are suppressed comprehensively,accompanied with the simultaneous improvement of beam quality and output power.The laser brightness is enhanced further by raising the threshold of transverse mode instability by approximately 1.0 kW by coiling the gain fiber with a novel curvature shape.Finally,a 6 kW narrow-linewidth laser is achieved with beam quality(M^(2))of approximately 1.4.The laser brightness doubled compared to the results before optimization.To the best of our knowledge,it is the highest brightness narrow-linewidth fiber laser based on a one-stage master oscillator power amplification structure.展开更多
The high-power mode-programmable orbital angular momentum(OAM)beam has attracted significant attention in a wide range of applications,such as long-distance optical communication,nonlinear frequency conversion,and bea...The high-power mode-programmable orbital angular momentum(OAM)beam has attracted significant attention in a wide range of applications,such as long-distance optical communication,nonlinear frequency conversion,and beam shaping.Coherent beam combining(CBC)of an optical phased array(OPA)can offer a promising solution for both generating the high-power OAM beam and rapidly switching the OAM modes.However,achieving real-time phase noise locking and formation of desired phase structures in a high-power CBC system faces significant challenges.Here,an internal phase-sensing technique was utilized to generate the high-power OAM beam,which effectively mitigated thermal effects and eliminated the need for large optical devices.An OPA with six elements was employed for experimental demonstration.The first effective generation of over 1.5 kW mode-programmable OAM beam in a continuous-wave domain was presented.Moreover,the results demonstrated that the generated OAM beam could be modulated with multiple dimensions.The topological charge can be switched in real time from-1 to-2.Notably,this OAM beam emitter could function as an OAM beam copier by easily transforming a single OAM beam into an OAM beam array.More importantly,a comprehensive analysis was conducted on power scaling,mode switching speed,and expansion of OAM modes.Additionally,the system’s compact design enabled it to function as a packageable OAM beam emitter.Owing to the advantages of having high power and programmable modes with multiple dimension modulation in phase structures and intensity distribution,this work can pave the way for producing high-power structured light beams and advancing their applications.展开更多
High-power single-frequency fiber lasers with diffraction-limited spots are indispensable for a wide range of photonic applications and are particularly in advanced detection and sensing technologies.However,the simul...High-power single-frequency fiber lasers with diffraction-limited spots are indispensable for a wide range of photonic applications and are particularly in advanced detection and sensing technologies.However,the simultaneous achievement of kilowatt-level output power and diffraction-limited beam quality has remained elusive in all reported single-frequency fiber laser systems to date,primarily due to limitations imposed by the stimulated Brillouin scattering(SBS)effect and transverse mode instability(TMI)effect.In this study,we demonstrate the design and manufacturing of an ultra-low numerical aperture(NA)functional Yb-doped fiber featuring a bat-type refractive index distribution,specifically engineered for single-frequency laser amplification.In the fabrication,we implemented multiple chelate gas filling and particle deposition iterations,leading to an active fiber with a bat-type refractive index distribution.The unique capabilities of this large mode area and high-order modes leakage fiber(HOMLF)were demonstrated by stably amplifying the single-frequency laser with more than one kilowatt output power and near single mode beam quality(M_(x)^(2)=1.10,M_(x)^(2)=1.18)for the first time.This fiber design advances the leap forward in single-frequency fiber lasers,which could contribute as a novel and efficient laser amplification technique for the next generation of gravitational wave detection systems.展开更多
Transverse mode instability(TMI),induced by nonlinear thermal-optical coupling,poses a primary challenge for the power scaling of fiber lasers.In the fiber oscillator,a sealed resonant cavity,TMI could become particul...Transverse mode instability(TMI),induced by nonlinear thermal-optical coupling,poses a primary challenge for the power scaling of fiber lasers.In the fiber oscillator,a sealed resonant cavity,TMI could become particularly complex due to the mode competition during the laser oscillation.While traditional theories of TMI predominantly address two-mode coupling,this paper explores the TMI phenomena in few-mode fiber oscillators utilizing a holistic approach that includes solving steady-state thermal-optic coupling equations.The simulation shows that there is a non-monotonic correlation between bending loss and the TMI threshold,which is contrary to the monotonic associations suggested by two-mode interaction theory.When one high-order mode experiences net gain,fluctuations of the TMI threshold would occur,leading to the amplification of a new mode within the uncoupled frequency region,thus affecting the gain saturation.By designing the linewidth of a low-reflection grating(LR),the modal power management in the uncoupled frequency domain can be achieved.An excessively broad LR linewidth exacerbates mode coupling within the shared frequency region,thus exacerbating TMI.To validate the theoretical simulation,we carefully fabricated LRs and optimized the fiber coiling to elevate the TMI threshold.Through careful optimization of LR linewidth and bending radii,we achieved a record-breaking laser output of 10.07kW using a monolithic fiber oscillator,with no observable evidence of TMI.Our work demonstrates that modal power redistribution in independent frequency domains offers a novel approach to mitigating TMI in high-power fiber lasers.Additionally,it provides new insights into mode decoupling strategies pertinent to fiber communications.展开更多
Bedding-parallel fibrous calcite veins(BPCVs)are found extensively in sedimentary basins and usually developed in petroleum source rock;however,their origin remains debated.This study investigates the formation of BPC...Bedding-parallel fibrous calcite veins(BPCVs)are found extensively in sedimentary basins and usually developed in petroleum source rock;however,their origin remains debated.This study investigates the formation of BPCVs in the Permian carbonate rocks of the Khao Khwang Formation,central Thailand,through petrographic,geochemical,and isotopic analyses,along with total organic carbon(TOC)content assessment.Five samples,including 9 veins and 5 host rocks,were analyzed.The petrographic obser-vations show that the BPCVs exhibit cone-in-cone structure and beef vein and are classified as unitaxial veins.The geochemical analyses and stable isotope compositions suggest local fluid sources originated from inorganic carbonates and diagenetic formation fluids within the microbial methanogenic zone.The BPCVs have an averageδ13 CVPDB value of 3.04‰±0.30‰and an averageδ18 OVPDB value of 10.75‰±0.62‰,while the host rocks have an averageδ13 CVPDB value of 1.88‰±1.10‰and an averageδ18 OVPDB value of 10.77‰±0.39‰.The mineral compositions and element contents of the host rock and fibrous calcite veins are similar,with a strong negative relationship between calcium and other ele-ments.The rare earth element(REE)distribution patterns from the calcite veins are similar to the host rocks,with positive Ce anomalies and small positive Eu anomalies.Oxygen isotope data suggest vein formation at temperatures between 62℃and 75℃,corresponding to the onset of the oil window.The in-situ U-Pb dating indicates that fibrous calcite veins formed between the Early to Middle Permian period[(260.1±4.5)to(288.9±4.8)Ma)].Microstructural and geochemical evidence suggests that vein initiation resulted from fluid overpressure of a supersaturation of pore fluids within semi-consolidated sediments,with continuous vein dilatation driven by crystallization forces.This study illustrates that the BPCVs of the Khao Khwang Formation highlight significant potential in accurately assessing the evolution of hydrocarbon generation.展开更多
基金supported by the National Key R&D Program of China(No.2022YFF0800200)the NSFC(Nos.U1812402 and 42072131)+6 种基金Most Special Fund(No.MSFGPMR33)from the State Key Laboratory of GPMRthe CUG Scholar Scientific Research Funds(No.2022036)the NSF of Hebei Province(No.D2021334001)Research Project of Talent Engineering Training of Hebei Province(No.B2020005007)Research Project of Postdoctoral Scientific Research Station of HBGMR(No.454-0602-YBN-Z9E4)Natural Science Foundation of Hebei Province(No.D2021334001)the Central Government Guides Local Funds for Scientific and Technological Development(No.236Z7608 G)。
文摘Original sedimentary manganese(Mn)deposits and supergene Mn ores are important Mn resources in China.However,the geochemical information from Chinese supergene Mn ores is scarce,and the relationship between sedimentary Mn deposits and supergene Mn ores is ambiguous.In this study,we collected the original Mn-bearing dolomitic sandstones(ZK20-3 drillcore)and supergene Mn ores(Longmen Section)from eastern Hebei,North China for systematic petrographic,mineralogical and geochemical analyses.Our new data help us to figure out the transformation from original Mn-bearing deposits to supergene ores.The main minerals of original Mn-bearing dolomitic sandstones are quartz and feldspar,with minor muscovite,dolomite,rhodochrosite,ankerite,and kutnohorite.Supergene Mn-oxide ores only emerged in the middle part of the Longmen(LM)Section,and mainly contain quartz,pyrolusite,cryptomelane,todorokite and occasional dolomite.The possible transformation sequence of Mn minerals is:kutnohorite/rhodochrosite→pyrolusite(Ⅰ)→cryptomelane(todorokite)→todorokite(cryptomelane)→pyrolusite(Ⅱ).For Mn-oxide ores,Fe,Na and Si are enriched but Al,Ca,Mg and K are depleted with the enrichment of Mn.For original and supergene ores,the total rare earth element+ytterbium(∑REY)contents range from 105.68×10^(-6)to 250.56×10^(-6)and from 18.08×10^(-6)to 176.60×10^(-6),respectively.Original Mn ores have similar slightly LREE-enriched patterns,but the purer Mn-oxide ore shows a HREE-enriched pattern.In the middle part of the LM Section,positive Ce anomalies in Mn-oxide ores indicate the precipitation of Ce-bearing minerals.It implies the existence of geochemical barriers,which changed p H and Eh values due to the long-time influence of groundwater.
基金support from the National Natural Science Foundation of China for Youths(21701059)the Natural Science Foundation of Jiangsu Province for Youths(BK20170571)support from the Postgraduate Research&Practice Innovation Program of Jiangsu Province(SJCX24_2600).
文摘Metal-organic frameworks(MOFs),with their ultrahigh specific surface area,uniformly distributed pores,and tunable structures,are promising candidates for next-generation active electrode materials in lithium-ion batteries(LIBs).However,their application is hindered by poor cycling stability due to structural collapse during charge-discharge cycles.To address this issue,we developed an alloy and multi-solvent thermal method strategy to synthesize Co/Zn bimetallic MOFs based on Naphthalenetetracarboxylic acid(NTCA).The resulting petal-like Co/Zn-NTCA MOF demonstrates outstanding electrochemical performance.The incorporation of zinc ions not only significantly enhances cycling stability but also markedly increases the specific capacity of the anode material.At a current density of 200 mA·g^(-1),the Co/Zn(2:1)-NTCA MOF demonstrated an impressive reversible capacity of 956 mA·h·g^(-1) after 150 cycles.Even after 500 cycles,the specific capacity of the electrode remained high,with a value of 438 mA·h·g^(-1) at a current density of 1000 A·g^(-1).
基金supported by the Large-scale Scientific Facilities of the Chinese Academy of Sciences(Grant No:2017-LSFGBOWS-02)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2015321)
文摘Burmanniaceae is one major group within the monocot order Dioscoreales that has not had its plastome sequenced.Members of Burmanniaceae are mostly achlorophyllous,although the genus Burmannia also includes autotrophs.Here,we report sequencing and analysis of the first Burmanniaceae plastid genome from Burmannia disticha L..This plastome is 157,480 bp and was assembled as a circular sequence with the typical quadripartite structure of plant plastid genomes.This plastome has a regular number of potentially functional genes with a total of 111,including 78 protein coding genes,4 ribosomal RNA(rRNA) genes,and 29 tRNA genes.The ratio of the total length of genic:intergenic DNA is 1.58:1,and the mean length of intergenic regions is 398 bp,the longest being 1918 bp.The overall GC content of the B.disticha plastome is 34.90%,and the IR regions in B.disticha are more GC rich(39.50%) than the LSC(32.30%) and SSC(28.80%) regions.Phylogenetic analysis of protein-coding sequences from plastomes of related species in the order Dioscoreales support a clade comprising Burmanniaceae and Dioscoreaceae.This phylogenetic placement is congruent with previous findings based on nuclear and mitochondrial evidence.
基金supported by the National Key R&D Program of China(No.2022YFB1903200)the National Natural Science Foundation of China(Nos.U23A2087,22372137,22102136,22072057,22227802,22172126)+2 种基金the Key Research and Development Program of Guangxi(No.GUIKE AB23026116)the Fundamental Research Funds for the Central Universities(Nos.20720220105,20720232005)the XMU Training Program of Innovation and Enterpreneurship for Undergraduates(Nos.2022Y1132,202310384027)。
文摘The photocatalytic conversion of biomass into high-value chemicals,coupled with simultaneous hydrogen(H_(2))evolution,leveraging the electrons and holes generated by solar energy,holds great promise for addressing energy demands.In this study,we constructed a dual functional photocatalytic system formed by NiS loaded on Ni doped two-dimensional(2D)CdS nanosheet(NiS/Ni-CdSNS)heterostructure for visible-light-driven H_(2)evolution and ethanol oxidation to acetaldehyde.Remarkably,the 2D NiS/NiCdSNS exhibited significant activity and selectivity in both photocatalytic H_(2)evolution and ethanol oxidation,achieving yields of 7.98 mmol g^(-1)h^(-1)for H_(2)and 7.33 mmol g^(-1)h^(-1)for acetaldehyde.The heterogeneous interface of the composite facilitated efficient charge separation,while NiS provided abundant sites for proton reduction,thereby promoting the overall dual-functional photocatalytic activity.Density functional theory calculations further reveal that both Ni doping and NiS loading can reduce the reaction energy barrier of ethanol oxidation of free radicals,and NiS/Ni-CdSNS composite materials exhibit stronger ethanol C-H activation ability to generate key intermediate·CH(OH)CH_(3)on the surface.This work serves as a valuable guide for the rational design of efficient dual functional photocatalytic systems that combine H_(2)evolution with the selective conversion of organic compounds into high-value chemicals.
基金supported by the National Key R&D Program of China(No.2022YFB1903200)the National Natural Science Foundation of China(nos.22372137,U23A2087,22227802,and 22472139)Researchers Supporting Project Number(RSP2025R304),King Saud University,Riyadh,Saudi Arabia。
文摘Solar-driven hydrogen(H_(2))evolution and contaminant degradation offer a promising pathway to address the global energy and environmental crisis.However,the inadequate separation of carriers and light absorption remain significant challenges in the advancement of photocatalysis.In this work,a general in situ ion exchange strategy has been employed to integrate palladium single atoms(Pd SAs)into hollow cadmium sulfide(CdS-H)spheres,creating a multifunctional photocatalyst for both photocatalytic H_(2)evolution and organic degradation.The hollow structure enhances light refraction,and Pd SAs act as charge transfer channels,leading to a significant enhancement in the spatial separation efficiency of photocatalytic charge carries pairs and light utilization in the synthesized Pd SAs/CdS-H.Consequently,the optimized 0.3Pd SAs/CdS-H demonstrates an exceptional photocatalytic H_(2) evolution efficiency of 22.23 mmol h^(-1)g^(-1)and an organic pollutant removal rate of 99.2%.Experimental analyses and density functional theory calculations reveal that the Pd SAs lower the work function of CdS-H and enhance the interfacial charge transport,which is crucial for improving photocatalytic performance.Moreover,both superoxide radicals and holes contribute to the removal of organic dyes,as directly confirmed by in situ radical capture experiments.Based on these characterization results,the photocatalytic mechanism for photocatalytic H_(2) evolution and pollutant degradation is proposed,respectively.This work establishes a dual-functional photocatalyst design strategy for sustainable energy generation and environmental remediation.
基金Project supported by the National Natural Science Foundation of China(Grant No.11935004).
文摘The development of reliable fusion energy is one of the most important challenges in this century.The accelerated degradation of structural materials in fusion reactors caused by neutron irradiation would cause severe problems.Due to the lack of suitable fusion neutron testing facilities,we have to rely on ion irradiation experiments to test candidate materials in fusion reactors.Moreover,fusion neutron irradiation effects are accompanied by the simultaneous transmutation production of helium and hydrogen.One important method to study the He-H synergistic effects in materials is multiple simultaneous ion beams(MSIB)irradiation that has been studied for decades.To date,there is no convincing conclusion on these He-H synergistic effects among these experiments.Recently,a multiple ion beam in-situ transmission electron microscopy(TEM)analysis facility was developed in Xiamen University(XIAMEN facility),which is the first triple beam system and the only in-running in-situ irradiation facility with TEM in China.In this work,we conducted the first high-temperature triple simultaneous ion beams irradiation experiment with TEM observation using the XIAMEN facility.The responses to in-situ triple-ion beams irradiation in austenitic steel 304L SS and ferritic/martensitic steel CLF-1 were studied and compared with the results in dual-and single-ion beam(s)irradiated steels.Synergistic effects were observed in MSIB irradiated steels.Helium was found to be critical for cavity formation,while hydrogen has strong synergistic effect on increasing swelling.
基金the National Natural Science Foundation of China(Grant Nos.62005313 and 62061136013).
文摘Impact of amplified spontaneous emission(ASE)noise on the stimulated Raman scattering(SRS)threshold of highpower fiber amplifiers is demonstrated numerically through a spectral evolution approach.The simulation results confirm that ASE noise in the Raman wavelength band could reduce the SRS threshold of high-power fiber amplifiers significantly.As for ASE noise originated the main amplifier,it becomes stronger and reduces the SRS threshold at shorter operation wavelength below 1052 nm.As for ASE noise originated from the seed laser,it reduces the SRS threshold at different operation wavelength under the condition that the Raman ratio is over-90 dB in the seed laser.The theoretical method and results in this work could provide a well reference to extend the operation wavelength of high-power fiber lasers.
基金the National Natural Science Foundation of China(Grant Nos.81530018,31371474,81370811,31570878 and 81300315).
文摘Macrophages play critical roles in renal fibrosis.However,macrophages exhibit ontogenic and functional heterogeneities,and which population of macrophages contributes to renal fibrosis and the underlying mechanisms remain unclear.In this study,we genetically targeted Notch signaling by disrupting the transcription factor recombination signal binding protein-JK(RBP-J),to reveal its role in regulation of macrophages during the unilateral ureteral obstruction(UUO)-induced murine renal fibrosis.Myeloid-specific disruption of RBP-J attenuated renal fibrosis with reduced extracellular matrix deposition and myofibroblast activation,as well as attenuated epithelial-mesenchymal transition,likely owing to the reduced expression of TGF-β.Mean while,RBP-J deletion significantly hampered macrophage infiltration and activation in fibrotic kidney,although their proliferation appeared unaltered.By using macrophage clearance experiment,we found that kidney resident macrophages made negligible contribution,but bone marrow(BM)-derived macrophages played a major role in renal fibrogenesis.Further mechanistic analyses showed that Notch blockade reduced monocyte emigration from BM by down-regulating CCR2 expression.Finally,we found that myeloid-specific Notch activation aggravated renal fibrosis,which was mediated by CCR2^+macrophages infiltration.In summary,our data have unveiled that myeloid-specific targeting of Notch could ameliorate renal fibrosis by regulating BM-derived macrophages recruitment and activation,providing a novel strategy for intervention of this disease.
基金sponsored by the National Natural Science Foundation of China (Nos. 61705264 and 61705265)
文摘An all-fiberized and narrow-bandwidth master oscillator power amplification(MOPA) system with record output power of 4 kW level and slope efficiency of 78% is demonstrated. Tandem pumping strategy is tentatively introduced into the narrow-bandwidth MOPA system for thermally induced mode instability(TMI) suppression. The stimulated Brillouin scattering(SBS) effect is balanced by simply using one-stage phase modulation technique. With different phase modulation signals, SBS limited output powers of 336 W, 1.2 kW and 3.94 kW are respectively achieved with spectral bandwidths accounting for 90% power of ～0.025, 0.17 and ～0.89 nm. Compared with our previous 976 nm pumping system, TMI threshold is overall boosted to be >5 times in which tandem pumping increases the TMI threshold of >3times. The beam quality(M～2 factor) of the output laser is well within 1.5 below the TMI threshold while it is ultimately saturated to be 1.86 with the influence of TMI at maximal output power. Except for SBS and TMI, stimulated Raman scattering(SRS) effect will be another challenge for further power scaling. In such a high power MOPA system, multidetrimental effects(SBS, SRS and TMI) will coexist and may be mutual-coupled, which could provide a well platform for further comprehensively investigating and optimizing the high power, narrow-bandwidth fiber amplifiers.
基金National Natural Science Foundation of China(61705264,61705265)Hunan Provincial Innovation Construct Project(2019RS3017)Natural Science Foundation of Hunan Province(2019JJ10005)。
文摘High-power mode-programmable orbital angular momentum(OAM)beams have received substantial attention in recent years.They are widely used in optical communication,nonlinear frequency conversion,and laser processing.To overcome the power limitation of a single beam,coherent beam combining(CBC)of laser arrays is used.However,in specific CBC systems used to generate structured light with a complex wavefront,eliminating phase noise and realizing flexible phase modulation proved to be difficult challenges.In this paper,we propose and demonstrate a two-stage phase control method that can generate OAM beams with different topological charges from a CBC system.During the phase control process,the phase errors are preliminarily compensated by a deep-learning(DL)network,and further eliminated by an optimization algorithm.Moreover,by modulating the expected relative phase vector and cost function,all-electronic flexible programmable switching of the OAM mode is realized.Results indicate that the proposed method combines the characteristics of DL for undesired convergent phase avoidance and the advantages of the optimization algorithm for accuracy improvement,thereby ensuring the high mode purity of the generated OAM beams.This work could provide a valuable reference for future implementation of high-power,fast switchable structured light generation and manipulation.
基金funding from the program for the National Science Foundation of China under Grant No.61322505the program for New Century Excellent Talents in University+1 种基金the Innovation Foundation for Excellent Graduates in National University of Defense Technology under Grant No.B120704the Hunan Provincial Innovation Foundation for Postgraduate under Grant No.CX2012B035
文摘We report on the high-power amplification of a 1064 nm linearly polarized laser in an all-fiber polarizationmaintained master oscillator power amplifier,which can operate at an output power level of 1.3 kW.The beam quality(M^2) was measured to be <1.2 at full power operation.The polarization extinction rate of the fiber amplifier was measured to be above 94% before mode instabilities(MIs) set in,which reduced to about 90% after the onset of MI.The power scaling capability of strategies for suppressing MI is analyzed based on a semianalytical model,the theoretical results of which agree with the experimental results.It shows that mitigating MI by coiling the gain fiber is an effective and practical method in standard double-cladding large mode area fiber,and,by tight coiling of the gain fiber to the radius of 5.5 cm,the MI threshold can be increased to three times higher than that without coiling or loose coiling.Experimental studies have been carried out to verify the idea,which has proved that MI was suppressed successfully in the amplifier by proper coiling.
基金supported by the National Key Research and Development Program of China (Grant No. 2018YFE0202402)the Shanghai Science and Technology Innovation Action Plan (Grant No. 20590780200)the National Natural Science Foundation of China (Grant Nos. 41530964 & 41942046)
文摘The Middle Miocene Climate Transition(MMCT,~14 Ma)is the largest cooling event in the Cenozoic“Coolhouse”,which significantly impacts the global chemical weathering pattern.In this paper,the responses of the MMCT global cooling event in the deep South China Sea were studied by clay mineral assemblages analysis of the oceanic red beds(ORB)at International Ocean Discovery Program(IODP)Expedition 368 Site U1502.The results show that the clay mineral assemblages of the ORB at Site U1502 are mainly composed of smectite(56–88%),illite(7–29%),and kaolinite(6–20%),without chlorite.The contents of these clay minerals and illite crystallinity show a four-stage variation pattern during early-middle Miocene(22.8–10.8 Ma).Smectite decreased from average 81%during 22.8–16.2 Ma and 16.2–14.4 Ma to average 67%during 13.8–10.8 Ma,with a rapid decrease of~14%during 14.4–13.8 Ma.On the contrary,illite and kaolinite increased rapidly by~8%and~6%,respectively,during 14.4–13.8 Ma.Illite crystallinity increased from average 0.18°Δ2θduring 22.8–16.2 Ma to average 0.19°Δ2θduring 16.2–14.4 Ma,and then decreased rapidly by~0.02°Δ2θduring 14.4–13.8 Ma.The provenance analysis of clay minerals shows that illite and kaolinite mainly originated from South China landmass due to physical erosion,while smectite mainly came from the Luzon arc as the product of chemical weathering.Therefore,smectite/illite ratio and illite crystallinity are used as proxies of chemical weathering intensity in the early-middle Miocene.High values of the ratio and the crystallinity represent the enhanced chemical weathering,whereas low values indicate the weakened chemical weathering or the strengthened physical erosion process.The smectite/illite ratio and illite crystallinity both decreased rapidly during 14.4–13.8 Ma,indicating the chemical weathering in the surrounding area of the South China Sea weakened rapidly,which we believe is the result of the MMCT event forcing.In addition,their values increased slightly during 16.2–14.4 Ma,which is in response to the relatively enhanced chemical weathering during the Middle Miocene Climate Optimum(MMCO).The variation pattern of clay mineral assemblages of the early-middle Miocene ORB in the South China Sea and its rapid transformation during the MMCT reveal that the Cenozoic cooling played a specific role in controlling the chemical weathering of the Earth’s surface.
基金supported by the Science and Technology Innovation Program of Hunan Province(No.2021RC4027)。
文摘In this paper,we have experimentally demonstrated a high-power and high-brightness narrow-linewidth fiber amplifier seeded by an optimized fiber oscillator.In order to improve the temporal stability,the fiber oscillator consists of a composite fiber Bragg grating-based cavity with an external feedback structure.By optimizing the forward and backward pumping ratio,the nonlinear effects and stimulated Raman scattering-induced mode distortion of the fiber amplifier are suppressed comprehensively,accompanied with the simultaneous improvement of beam quality and output power.The laser brightness is enhanced further by raising the threshold of transverse mode instability by approximately 1.0 kW by coiling the gain fiber with a novel curvature shape.Finally,a 6 kW narrow-linewidth laser is achieved with beam quality(M^(2))of approximately 1.4.The laser brightness doubled compared to the results before optimization.To the best of our knowledge,it is the highest brightness narrow-linewidth fiber laser based on a one-stage master oscillator power amplification structure.
基金supported by the National Natural Science Foundation of China(Nos.62275272 and 62075242)Natural ScienceFoundationofHunanProvince,China(No.2019JJ10005)+1 种基金Training Program for Excellent Young Innovators of Changsha(No.kq2206003)Postgraduate Scientific Research Innovation Project of Hunan Province(No.QL20220013)。
文摘The high-power mode-programmable orbital angular momentum(OAM)beam has attracted significant attention in a wide range of applications,such as long-distance optical communication,nonlinear frequency conversion,and beam shaping.Coherent beam combining(CBC)of an optical phased array(OPA)can offer a promising solution for both generating the high-power OAM beam and rapidly switching the OAM modes.However,achieving real-time phase noise locking and formation of desired phase structures in a high-power CBC system faces significant challenges.Here,an internal phase-sensing technique was utilized to generate the high-power OAM beam,which effectively mitigated thermal effects and eliminated the need for large optical devices.An OPA with six elements was employed for experimental demonstration.The first effective generation of over 1.5 kW mode-programmable OAM beam in a continuous-wave domain was presented.Moreover,the results demonstrated that the generated OAM beam could be modulated with multiple dimensions.The topological charge can be switched in real time from-1 to-2.Notably,this OAM beam emitter could function as an OAM beam copier by easily transforming a single OAM beam into an OAM beam array.More importantly,a comprehensive analysis was conducted on power scaling,mode switching speed,and expansion of OAM modes.Additionally,the system’s compact design enabled it to function as a packageable OAM beam emitter.Owing to the advantages of having high power and programmable modes with multiple dimension modulation in phase structures and intensity distribution,this work can pave the way for producing high-power structured light beams and advancing their applications.
基金support from the National Key Research and Development Program of China(2022YFB3606400).
文摘High-power single-frequency fiber lasers with diffraction-limited spots are indispensable for a wide range of photonic applications and are particularly in advanced detection and sensing technologies.However,the simultaneous achievement of kilowatt-level output power and diffraction-limited beam quality has remained elusive in all reported single-frequency fiber laser systems to date,primarily due to limitations imposed by the stimulated Brillouin scattering(SBS)effect and transverse mode instability(TMI)effect.In this study,we demonstrate the design and manufacturing of an ultra-low numerical aperture(NA)functional Yb-doped fiber featuring a bat-type refractive index distribution,specifically engineered for single-frequency laser amplification.In the fabrication,we implemented multiple chelate gas filling and particle deposition iterations,leading to an active fiber with a bat-type refractive index distribution.The unique capabilities of this large mode area and high-order modes leakage fiber(HOMLF)were demonstrated by stably amplifying the single-frequency laser with more than one kilowatt output power and near single mode beam quality(M_(x)^(2)=1.10,M_(x)^(2)=1.18)for the first time.This fiber design advances the leap forward in single-frequency fiber lasers,which could contribute as a novel and efficient laser amplification technique for the next generation of gravitational wave detection systems.
基金support from the National Natural Science Foundation of China(NSFC)(62405373,11974427)the Science and Technology Innovation Program of Hunan Province(2021RC4027).
文摘Transverse mode instability(TMI),induced by nonlinear thermal-optical coupling,poses a primary challenge for the power scaling of fiber lasers.In the fiber oscillator,a sealed resonant cavity,TMI could become particularly complex due to the mode competition during the laser oscillation.While traditional theories of TMI predominantly address two-mode coupling,this paper explores the TMI phenomena in few-mode fiber oscillators utilizing a holistic approach that includes solving steady-state thermal-optic coupling equations.The simulation shows that there is a non-monotonic correlation between bending loss and the TMI threshold,which is contrary to the monotonic associations suggested by two-mode interaction theory.When one high-order mode experiences net gain,fluctuations of the TMI threshold would occur,leading to the amplification of a new mode within the uncoupled frequency region,thus affecting the gain saturation.By designing the linewidth of a low-reflection grating(LR),the modal power management in the uncoupled frequency domain can be achieved.An excessively broad LR linewidth exacerbates mode coupling within the shared frequency region,thus exacerbating TMI.To validate the theoretical simulation,we carefully fabricated LRs and optimized the fiber coiling to elevate the TMI threshold.Through careful optimization of LR linewidth and bending radii,we achieved a record-breaking laser output of 10.07kW using a monolithic fiber oscillator,with no observable evidence of TMI.Our work demonstrates that modal power redistribution in independent frequency domains offers a novel approach to mitigating TMI in high-power fiber lasers.Additionally,it provides new insights into mode decoupling strategies pertinent to fiber communications.
基金supported by the Ratchadaphisek Somphot Endowment Fund(the 90th Anniversary of Chulalongkorn University Fund,GCUGR1125662052Mthe Exchange Faculty Travel Grant,CTG168038)。
文摘Bedding-parallel fibrous calcite veins(BPCVs)are found extensively in sedimentary basins and usually developed in petroleum source rock;however,their origin remains debated.This study investigates the formation of BPCVs in the Permian carbonate rocks of the Khao Khwang Formation,central Thailand,through petrographic,geochemical,and isotopic analyses,along with total organic carbon(TOC)content assessment.Five samples,including 9 veins and 5 host rocks,were analyzed.The petrographic obser-vations show that the BPCVs exhibit cone-in-cone structure and beef vein and are classified as unitaxial veins.The geochemical analyses and stable isotope compositions suggest local fluid sources originated from inorganic carbonates and diagenetic formation fluids within the microbial methanogenic zone.The BPCVs have an averageδ13 CVPDB value of 3.04‰±0.30‰and an averageδ18 OVPDB value of 10.75‰±0.62‰,while the host rocks have an averageδ13 CVPDB value of 1.88‰±1.10‰and an averageδ18 OVPDB value of 10.77‰±0.39‰.The mineral compositions and element contents of the host rock and fibrous calcite veins are similar,with a strong negative relationship between calcium and other ele-ments.The rare earth element(REE)distribution patterns from the calcite veins are similar to the host rocks,with positive Ce anomalies and small positive Eu anomalies.Oxygen isotope data suggest vein formation at temperatures between 62℃and 75℃,corresponding to the onset of the oil window.The in-situ U-Pb dating indicates that fibrous calcite veins formed between the Early to Middle Permian period[(260.1±4.5)to(288.9±4.8)Ma)].Microstructural and geochemical evidence suggests that vein initiation resulted from fluid overpressure of a supersaturation of pore fluids within semi-consolidated sediments,with continuous vein dilatation driven by crystallization forces.This study illustrates that the BPCVs of the Khao Khwang Formation highlight significant potential in accurately assessing the evolution of hydrocarbon generation.
