Discovery of materials using“bottom-up”or“top-down”approach is of great interest in materials science.Layered materials consisting of two-dimensional(2D)building blocks provide a good platform to explore new mater...Discovery of materials using“bottom-up”or“top-down”approach is of great interest in materials science.Layered materials consisting of two-dimensional(2D)building blocks provide a good platform to explore new materials in this respect.In van der Waals(vdW)layered materials,these building blocks are charge neutral and can be isolated from their bulk phase(top-down),but usually grow on substrate.In ionic layered materials,they are charged and usually cannot exist independently but can serve as motifs to construct new materials(bottom-up).In this paper,we introduce our recently constructed databases for 2D material-substrate interface(2DMSI),and 2D charged building blocks.For 2DMSI database,we systematically build a workflow to predict appropriate substrates and their geometries at substrates,and construct the 2DMSI database.For the 2D charged building block database,1208 entries from bulk material database are identified.Information of crystal structure,valence state,source,dimension and so on is provided for each entry with a json format.We also show its application in designing and searching for new functional layered materials.The 2DMSI database,building block database,and designed layered materials are available in Science Data Bank at https://doi.org/10.57760/sciencedb.j00113.00188.展开更多
It is a major challenge for the airframe-inlet design of modern combat aircrafts,as the flow and electromagnetic wave propagation in the inlet of stealth aircraft are very complex.In this study,an aerodynamic/stealth ...It is a major challenge for the airframe-inlet design of modern combat aircrafts,as the flow and electromagnetic wave propagation in the inlet of stealth aircraft are very complex.In this study,an aerodynamic/stealth optimization design method for an S-duct inlet is proposed.The upwind scheme is introduced to the aerodynamic adjoint equation to resolve the shock wave and flow separation.The multilevel fast multipole algorithm(MLFMA)is utilized for the stealth adjoint equation.A dorsal S-duct inlet of flying wing layout is optimized to improve the aerodynamic and stealth characteristics.Both the aerodynamic and stealth characteristics of the inlet are effectively improved.Finally,the optimization results are analyzed,and it shows that the main contradiction between aerodynamic characteristics and stealth characteristics is the centerline and crosssectional area.The S-duct is smoothed,and the cross-sectional area is increased to improve the aerodynamic characteristics,while it is completely opposite for the stealth design.The radar cross section(RCS)is reduced by phase cancelation for low frequency conditions.The method is suitable for the aerodynamic/stealth design of the aircraft airframe-inlet system.展开更多
Objective Thrombotic thrombocytopenic purpura(TTP)is a rare and fatal disease caused by a severe deficiency in the metalloprotease ADAMTS13 and is characterized by thrombotic microangiopathy.The present study aimed to...Objective Thrombotic thrombocytopenic purpura(TTP)is a rare and fatal disease caused by a severe deficiency in the metalloprotease ADAMTS13 and is characterized by thrombotic microangiopathy.The present study aimed to investigate the genes and variants associated with TTP in a Chinese population.Methods Target sequencing was performed on 220 genes related to complements,coagulation factors,platelets,fibrinolytic,endothelial,inflammatory,and anticoagulation systems in 207 TTP patients and 574 controls.Subsequently,logistic regression analysis was carried out to identify the TTP-associated genes based on the counts of rare deleterious variants in the region of a certain gene.Moreover,the associations between common variants and TTP were also investigated.Results ADAMTS13 was the only TTP-associated gene(OR=3.77;95%CI:1.82–7.81;P=3.6×10^(-4))containing rare deleterious variants in TTP patients.Among these 8 variants,5 novel rare variants that might contribute to TTP were identified,including rs200594025,rs782492477,c.T1928G(p.I643S),c.3336_3361del(p.Q1114Afs*20),and c.3469_3470del(p.A1158Sfs*17).No common variants associated with TTP were identified under the stringent criteria of correction for multiple testing.Conclusion ADAMTS13 is the primary gene related to TTP.The genetic variants associated with the occurrence of TTP were slightly different between the Chinese and European populations.展开更多
Currently,the video captioning models based on an encoder-decoder mainly rely on a single video input source.The contents of video captioning are limited since few studies employed external corpus information to guide...Currently,the video captioning models based on an encoder-decoder mainly rely on a single video input source.The contents of video captioning are limited since few studies employed external corpus information to guide the generation of video captioning,which is not conducive to the accurate descrip-tion and understanding of video content.To address this issue,a novel video captioning method guided by a sentence retrieval generation network(ED-SRG)is proposed in this paper.First,a ResNeXt network model,an efficient convolutional network for online video understanding(ECO)model,and a long short-term memory(LSTM)network model are integrated to construct an encoder-decoder,which is utilized to extract the 2D features,3D features,and object features of video data respectively.These features are decoded to generate textual sentences that conform to video content for sentence retrieval.Then,a sentence-transformer network model is employed to retrieve different sentences in an external corpus that are semantically similar to the above textual sentences.The candidate sentences are screened out through similarity measurement.Finally,a novel GPT-2 network model is constructed based on GPT-2 network structure.The model introduces a designed random selector to randomly select predicted words with a high probability in the corpus,which is used to guide and generate textual sentences that are more in line with human natural language expressions.The proposed method in this paper is compared with several existing works by experiments.The results show that the indicators BLEU-4,CIDEr,ROUGE_L,and METEOR are improved by 3.1%,1.3%,0.3%,and 1.5%on a public dataset MSVD and 1.3%,0.5%,0.2%,1.9%on a public dataset MSR-VTT respectively.It can be seen that the proposed method in this paper can generate video captioning with richer semantics than several state-of-the-art approaches.展开更多
Silicon carbide(SiC) is a promising platform for fabricating high-voltage, high-frequency and high-temperature electronic devices such as metal oxide semiconductor field effect transistors in which many junctions or i...Silicon carbide(SiC) is a promising platform for fabricating high-voltage, high-frequency and high-temperature electronic devices such as metal oxide semiconductor field effect transistors in which many junctions or interfaces are involved. The work function(WF) plays an essential role in these devices. However, studies of the effect of conductive type and polar surfaces on the WF of SiC are limited. Here, we report the measurement of WFs of Si-and C-terminated polar surfaces for both p-type and n-type conductive 4H-SiC single crystals by scanning Kelvin probe microscopy(SKPFM). The results show that p-type SiC exhibits a higher WF than n-type SiC.The WF of a C-terminated polar surface is higher than that of a Si-terminated polar surface, which is further confirmed by first-principles calculations. By revealing this long-standing knowledge gap, our work facilitates the fabrication and development of SiC-based electronic devices, which have tremendous potential applications in electric vehicles, photovoltaics, and so on. This work also shows that SKPFM is a good method for identifying polar surfaces of SiC and other polar materials nondestructively, quickly and conveniently.展开更多
By analyzing the factors which affect the wall-plug efficiency of semiconductor Laser Diodes (LDs), a high efficiency 1060 nm LD was designed, including active region, waveguide layers, and cladding layers. The simula...By analyzing the factors which affect the wall-plug efficiency of semiconductor Laser Diodes (LDs), a high efficiency 1060 nm LD was designed, including active region, waveguide layers, and cladding layers. The simulation result shows that the component of In in InGaAs in the active region cannot be too small, otherwise the thickness of InGaAs active layer will exceed the critical thickness, meanwhile the asymmetric large optical cavity can decrease the cavity loss effectively. The epitaxial structure was grown by MOCVD, experimental results of varying cavity length showed that the internal quantum efficiency reached 98.57%, and the cavity loss was only 0.273 cm?1. Devices with 4 mm-cavity-length and 100 μm-strip-width were fabricated, 47.4% wall-plug efficiency was reached under QCW pulse condition at room temperature, and the peak wavelength was 1059.4 nm.展开更多
This paper is focused on a 940 nm edge type of semiconductor laser, which is made from 940 nm InGaAs double-quantum-well epitaxial wafer, produced by Metal Organic Chemical Vapor Deposition (MOCVD). In the absence of ...This paper is focused on a 940 nm edge type of semiconductor laser, which is made from 940 nm InGaAs double-quantum-well epitaxial wafer, produced by Metal Organic Chemical Vapor Deposition (MOCVD). In the absence of coating, the efficiency at the room temperature is 0.89 W/A, and the averaged threshold current is 0.307 A. The present study investigates the impact of temperature on the P-I curve, V-I curve and the centre wavelength, the temperature ranging from 286.15 - 333.15 K. It shows that the threshold current increases from 0.28 A to 0.41 A with the increasing temperature. The increase rate is 0.0027 A/K. With the temperature ranging from 286.15 - 333.15 K, the characteristic temperature is calculated to be 120 K. At driven current of 2 A, the output power decreases from 1.47 W to 1.27 W at a rate of 0.00425 W/K. At a constant voltage, the output current initially increases with the temperature within a certain range, beyond which the impact of the temperature is minimum. The ideal factor obtained from V-I curve by curve fitting is 1.076. The series resistance is 0.609 Ω. The centre wavelength shifts to a longer wavelength with the increasing temperature at a rate of 0.275288 nm/K.展开更多
The Jiaodong gold deposits are currently the most important gold resources（with Au reserves of〉4000 t） in China,and the leading gold-producing country globally（with Au production of ～428 t in2013）.Jiaodong is al...The Jiaodong gold deposits are currently the most important gold resources（with Au reserves of〉4000 t） in China,and the leading gold-producing country globally（with Au production of ～428 t in2013）.Jiaodong is also considered as perhaps the only world-class to giant gold accumulation on the planet where relatively young gold ores（ca.130-120 Ma） were deposited in rocks that are 2 Ga older.The Xincheng world-class high-grade gold deposit,with a proven reserve of 〉200 t gold,is one of the largest deposits in the giant gold province of the Jiaodong Peninsula.It is located in the northwestern part of the jiaobei Uplift,and hosted by ca.132-123 Ma Xincheng quartz monzonites and monzogranites.Ore zones are structurally controlled by the NE-trending and NW-dipping Jiaojia Fault and subsidiary faults,and are mainly restricted to the footwall of the fault.The dominant disseminated- and stockworkstyle ores are associated with strong sericitization,silicification,sulfidation and K-feldspathization,and minor carbonate wallrock alteration halos.The four mineralization stages are pyrite-quartz-sericite（stage 1）,quartz-pyrite（stage 2）,quartz-polysulfide（stage 3） and quartz-carbonate（stage 4）.Gold occurs dominantly as electrum,with lesser amounts of sulfide-hosted native gold and rare native silver and argentite,normally associated with pyrite,chalcopyrite,galena and sphalerite：the latter with proven resources of about 105 t Ag,713 t Cu,and 5100 t S.There are three types of ore-related fluid inclusions：type 1 aqueous-carbonate（H2O-CO2）,type 2aqueous（liquid H2O＋vapor H2O）,and type 3 CO2（liquid CO2 and vapor CO2） inclusions.Homogenization temperatures range from 221 to 304℃ for type 1 inclusions,with salinities of 2.4-13.3 wt.%NaCl eq.,and bulk densities of 0.858-1.022 g/cm～3.The δ～（34）S（CDT） values of hydrothermal sulfides are 4.3-10.6‰and δ～（18）O values of hydrothermal quartz have a median value of 13.0‰.δD values of fluid inclusions in hydrothermal quartz have a median value of-75‰.Calculated δ～（18）Owater has a median value of 5.2‰.The timing of gold mineralization at the Xincheng gold deposit is younger than 123±1 Ma,and likely between 120.9 and 119.9 Ma.A minerals system genetic model for the probable epizonal orogenic Xincheng deposit suggests an initial medium temperature,CO2-rich,and low salinity H2O-CO2 deeply sourced metamorphic ore fluid associated with dehydration and decarbonization of subducting Paleo-Pacific lithosphere.The Jiaojia Fault constrained the migration of ore-forming fluids and metals at the brittle-ductile transition.Fluid immiscibility,caused by episodic pressure drops,led to significant high-grade gold deposition in the giant Xincheng gold deposit.展开更多
AIM To assess daclatasvir plus asunaprevir(d UAL) in treatment-na?ve patients from China's Mainland, Russia and South Korea with hepatitis C virus(HCV) genotype 1 b infection. METHODS Patients were randomly assign...AIM To assess daclatasvir plus asunaprevir(d UAL) in treatment-na?ve patients from China's Mainland, Russia and South Korea with hepatitis C virus(HCV) genotype 1 b infection. METHODS Patients were randomly assigned(3:1) to receive 24 wk of treatment with d UAL(daclatasvir 60 mg once daily and asunaprevir 100 mg twice daily) beginning on day 1 of the treatment period(immediate treatment arm) or following 12 wk of matching placebo(placebodeferred treatment arm). The primary endpoint was a comparison of sustained virologic response at posttreatment week 12(SVR12) compared with the historical SVR rate for peg-interferon plus ribavirin(70%) among patients in the immediate treatment arm. The first 12 wk of the study were blinded. Safety was assessed in d UAL-treated patients compared with placebo patients during the first 12 wk(doubleblind phase), and during 24 wk of d UAL in both arms combined.RESULTS In total, 207 patients were randomly assigned to immediate(n = 155) or placebo-deferred(n = 52) treatment. Most patients were Asian(86%), female(59%) and aged < 65 years(90%). Among them, 13% had cirrhosis, 32% had IL28 B non-CC genotypes and 53% had baseline HCV RNA levels of ≥ 6 million IU/m L. Among patients in the immediate treatment arm, SVR12 was achieved by 92%(95% confidence interval: 87.2-96.0), which was significantly higher than the historical comparator rate(70%). SVR12 was largely unaffected by cirrhosis(89%), age ≥ 65 years(92%), male sex(90%), baseline HCV RNA ≥ 6 million(89%) or IL28 B non-CC genotypes(96%), although SVR12 was higher among patients without(96%) than among those with(53%) baseline NS5 A resistanceassociated polymorphisms(at L31 or Y93 H). during the double-blind phase, aminotransferase elevations were more common among placebo recipients than among patients receiving d UAL. during 24 wk of d UAL therapy(combined arms), the most common adverse events(≥ 10%) were elevated alanine aminotransferase and upper respiratory tract infection; emergent grade 3-4 laboratory abnormalities were infrequently observed, and all grade 3-4 aminotransferase abnormalities(alanine aminotransferase, n = 9; aspartate transaminase, n = 6) reversed within 8-11 d. Two patients discontinued d UAL treatment; one due to aminotransferase elevations, nausea, and jaundice and the other due to a fatal adverse event unrelated to treatment. There were no treatment-related deaths.CONCLUSION d UAL was well-tolerated during this phase 3 study, and SVR12 with d UAL treatment(92%) exceeded thehistorical SVR rate for peg-interferon plus ribavirin of 70%.展开更多
Orogenic disseminated and Carlin gold deposits share much similarity in alteration and mineralization.The disseminated orogenic Zhenyuan Au deposit along the Ailaoshan shear zone,southeastern Tibet,was selected to cla...Orogenic disseminated and Carlin gold deposits share much similarity in alteration and mineralization.The disseminated orogenic Zhenyuan Au deposit along the Ailaoshan shear zone,southeastern Tibet,was selected to clarify their difference.The alteration and mineralization from the different lithologies,including meta-quartz sandstone,carbonaceous slate,meta-(ultra)mafic rock,quartz porphyry and lamprophyre were researched.According to the mineral assemblage and replacement relationship in all types of host rocks,two reactions show general control on gold deposition:(1) replacement of earlier magnetite by pyrite and carbonaceous material;(2) alteration of biotite and phlogopite phenocrysts in quartz porphyry and lamprophyre into dolomite/ankerite and sericite.Despite the lamprophyre is volumetrically minor and much less fractured than other host rocks,it contains a large portion of Au reserve,indicating that the chemically active lithology has played a more important role in gold precipitation compared to structure.LA-ICP-MS analysis shows that Au mainly occurs as invisible gold in fine-grained pyrite disseminated in the host rocks,with Au content reaching to 258.95 ppm.The diagenetic core of pyrite in meta-quartz sandstone enriched in Co,Ni,Mo,Ag and Hg is wrapped by hydrothermal pyrite enriched in Cu,As,Sb,Au,Tl,Pb and Bi.Different host rock lithology has much impact on the alteration and mineralization features.Carbonate and sericite in altered lamprophyre show they have higher Mg than those developed in other of host rocks denoting that the carbonate and sericite incorporated Mg from phlogopite phenocrysts in the primary lamprophyre during alteration.The ore fluid activated the diagenetic pyrite in meta-quartz sandstone leading the hydrothermal pyrite enriched in Cu,Mo,Ag,Sb,Te,Hg,Tl,Pb and Bi,but the hydrothermal pyrite in meta-(ultra)mafic rock is enriched in Co and Ni as the meta-(ultra)mafic rock host rock contain high content of Co and Ni.However,Au and As shear similar range in both types of host rocks indicating that these two elements most likely come from the deep source fluid rather than the host rocks.It was shown in the disseminated orogenic gold deposit that similar hydrothermal alteration with mineral assemblage of carbonate (mainly dolomite and ankerite),sericite,pyrite and arsenopyrite develops in all types of host rocks.This is different from the Nevada Carlin type,in which alteration is mainly dissolution and silicification of carbonate host rock.On the other hand,Au mainly occur as invisible gold in both disseminated orogenic and Carlin gold deposits.展开更多
The current margins of the North China and Yangtze Cratons provide arguably the best examples globally of anomalously high mineral endowment within a 100 km buffer zone,hosting 66 diverse world-class to giant ore syst...The current margins of the North China and Yangtze Cratons provide arguably the best examples globally of anomalously high mineral endowment within a 100 km buffer zone,hosting 66 diverse world-class to giant ore systems that help explain China’s premier position as a producer of multiple metal and mineral commodities.After the cratonization of these crustal blocks during the Neoarchean-Paleoproterozoic,with incorporation of iron ores on assembled micro-block margins,the margins of the cratons experienced multiple convergence and rifting events leading to metasomatism and fertilization of their underlying sub-continental lithospheric mantle.The rifted margins with trans-lithosphere faults provided pathways for Cu-Au(Mo-W-Sn)-bearing felsic to Ni-Cu-bearing ultrabasic intrusions and REE-rich carbonatite magmas,and for the development of marginal sedimentary basins with both Cu-Pb-Zn-rich source units and reactive carbonate or carbonaceous host rocks.There was diachronous formation of hydrothermal orogenic gold,antimony,and bismuth systems in the narrow orogenic belts between the cratons.Complexity in the Mesozoic Paleo-Pacific subduction systems resulted in asthenosphere upwelling and lithosphere extension and thinning in the North China Craton,leading to anomalous heat flow and formation of orogenic gold deposits,including those of the giant Jiaodong gold province on its north-eastern margin.These gold deposits,many of which formed from fluids liberated by devolatilization of previously metasomatized sub-continental lithospheric mantle,helped propel China to be the premier gold producer globally.The thick sub-continental lithospheric mantle of the cold buoyant cratons helped the preservation of some of the world’s oldest porphyry-skarn and epithermal mineral systems.Although craton margins globally control the formation and preservation of a diverse range of mineral deposits,China represents the premier example in terms of metal endowment due to the anomalous length of its craton margins combined with their abnormally complex tectonic history.展开更多
In this study,we used plasma factor V activity and parameters of the thrombin generation test to discuss their diagnostic and prognostic value for disseminated intravascular coagulation (DIC) in patients with hematolo...In this study,we used plasma factor V activity and parameters of the thrombin generation test to discuss their diagnostic and prognostic value for disseminated intravascular coagulation (DIC) in patients with hematological malignancies.A total of 164 patients who were diagnosed with hematological malignancies in the Department of Hematology,Union Hospital,between Apr 2014 and Dec.2014 were enrolled in this study.There were 131 patients in the study group and 33 patients in the control group in terms of the laboratory results for DIC.The patients in the study group were divided into a DIC subgroup (n=59) and a non-DIC subgroup (n=72) based on the International Society of Thrombosis and Hemostasis (ISTH) Integral System,and they were divided into four subgroups [score ≤3 (n=35),score=4 (n=37),score=5 (n=47),and score >6 (n=12)] according to ISTH scores.Using 28-day mortality as the endpoint,the patients in the study group were divided into a survival subgroup (n=111) and a non-survival subgroup (n=20).The results showed that the plasma factor V activity was significantly weaker,and lag time and time to peak were significantly shorter in the study group than in the control group (P<0.01).The factor V activity,peak and endogenous thrombin potential (ETP) were significantly decreased in the DIC subgroup as compared with those in the non-DIC subgroup (P<0.01).Among factor V activity,lag time,peak,ETP,and ttPeak,only the factor V activity was significantly decreased in the nonsurvival subgroup compared with the survival subgroup (P<0.01).With the increase in ISTH score,the ETP and peak decreased gradually.The binary logistic regression analysis revealed that PLT,D-dimer,factor V activity and ETP had linear relationship with DIC diagnosed by ISTH Integral System.Using DIC diagnosed by ISTH Integral System as the endpoint,the area under curve (AUC) of factor V activity was found to be similar to that of blood platelet count (PLT) and prothrombin time (PT).In conclusion,factor V activity,ETP and peak had diagnostic value for DIC in patients with hematological malignancies,and only factor V activity had limited prognostic value.展开更多
In underground mines, high air temperatures in the summer months lead to an increase in inlet airflow temperatures. This leads to seasonal thermal pollution in the mines. This paper examines the dynamics and effects o...In underground mines, high air temperatures in the summer months lead to an increase in inlet airflow temperatures. This leads to seasonal thermal pollution in the mines. This paper examines the dynamics and effects of seasonal variation in surface air temperatures and surrounding rock temperatures in deep coal mines. It also examines temperature variations in the main ventilation circuit, working face, and surrounding rock. The study results revealed that airflow temperatures were significantly affected by seasonal air temperature variations. The greater the distance was between the inlet and the wellhead of the ventilation shaft, the less the effect was on temperature. Moreover, slight temperature variations (1.0-3.0 ℃) were observed between various points on the return route during the summer months. Airflow temperatures along the airflow inlet to the return route of the working face first decreased, but then increased. The temperature field of the surrounding rock increased gradually with increased distance between the mine roadway and inlet, with recorded rock temperatures as high as 40.53 ℃. The radius of the heat-adjusting layer was between 28 and 33 m.展开更多
The gold deposits in the Youjiang basin,totaling>25 Moz gold,have traditionally been thought to be of Carlin-type,particularly those with extensional structural geometries in the northern basin dominated by platfor...The gold deposits in the Youjiang basin,totaling>25 Moz gold,have traditionally been thought to be of Carlin-type,particularly those with extensional structural geometries in the northern basin dominated by platform sedimentary sequences.However,the structural geometries,mineralization styles and alteration types for the Jinya,Gaolong and Nakuang gold deposits in the south-central part of the basin are remarkably similar to those of unequivocal orogenic gold deposits.Structural studies show that gold mineralization in the three gold deposits was controlled by tight“locked-up”anticlines with NW−SE-to E−W-trending and/or concomitant thrusts and/or shear zones,which resulted from NE−SW-to N–S-trending compression or transpression following the Early Triassic closure of the Paleo-Tethyan Ocean.Alteration zones in these deposits are dominated by silicification(quartz),sericitization,sulfidation and carbonation.Zoned pyrites in these deposits comprise Au-poor cores and invisible Au-bearing rims with minor external free gold.Euhedral to subhedral auriferous arsenopyrites also contribute to the gold budget.These features indicate that the three gold deposits are sediment-hosted orogenic gold deposits that contrast markedly with the Carlin-type gold deposits in the northern part of the Youjiang basin in terms of structural geometry and timing,mineralization style and nature of associated alteration.Although additional reliable ages using robust methodologies are still required,the older isotopic ages of the gold deposits in the south-central Youjiang basin are also consistent with earlier formation during transpression that predated extension during orogenic collapse,the period of formation of the Carlin-type gold deposits in the northern Youjiang basin.展开更多
Magmatic-hydrothermal Sn deposits are commonly associated with high silica magmas,but why most global high silica granites do not bear economic Sn ore grades remains unclear.Two crucial factors controlling magmatic-hy...Magmatic-hydrothermal Sn deposits are commonly associated with high silica magmas,but why most global high silica granites do not bear economic Sn ore grades remains unclear.Two crucial factors controlling magmatic-hydrothermal Sn mineralization,including advanced fractionation and depressurization-induced rapid cooling,were revealed in the case study of the Guyong granitic pluton linked with the Xiaolonghe Sn deposit,in the Tengchong block,SW China.The Guyong granitic pluton comprises three petrological facies:less evolved biotite syenogranite,evolved alkali granite and leucogranite,and highly evolved facies(the protolith of greisenized granite).Similar crystallization ages(~77 Ma)and gradual contact between different petrological facies indicate the Guyong granitic pluton records a continuous fractionation process.Monte Carlo-revised Rayleigh fractionation model suggests the fractionation degree of the Guyong pluton is markedly high(>87 wt.%)that can only be achieved by a high initial water(≥4 wt.%)content in the parent granitic magma revealed by rhyolite-MELTS calculation.Advanced degree fractionation causes the first Sn enrichment but it also significantly increases the viscosity of evolved magmas,suppressing the exsolution and transport of hydrothermal fluids.Hence,it must be compensated by the second critical factor:depressurization-induced rapid cooling,reflected by the occurrence of highly metamict zircons in the greisenized granite.The highly metamict feature,indicated by the large full width at half maximum(FWHM)values of zirconν3(SiO_(4)) peak(>19.5 cm^(-1)),suggests these zircons do not experience thermal annealing but rapidly ascend into a shallow cooling environment.Depressurization-induced rapid cooling facilitates exsolution and transport of hydrothermal fluids,interacting with wall rocks and resulting in Sn mineralization.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61888102,52272172,and 52102193)the Major Program of the National Natural Science Foundation of China(Grant No.92163206)+2 种基金the National Key Research and Development Program of China(Grant Nos.2021YFA1201501 and 2022YFA1204100)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB30000000)the Fundamental Research Funds for the Central Universities.
文摘Discovery of materials using“bottom-up”or“top-down”approach is of great interest in materials science.Layered materials consisting of two-dimensional(2D)building blocks provide a good platform to explore new materials in this respect.In van der Waals(vdW)layered materials,these building blocks are charge neutral and can be isolated from their bulk phase(top-down),but usually grow on substrate.In ionic layered materials,they are charged and usually cannot exist independently but can serve as motifs to construct new materials(bottom-up).In this paper,we introduce our recently constructed databases for 2D material-substrate interface(2DMSI),and 2D charged building blocks.For 2DMSI database,we systematically build a workflow to predict appropriate substrates and their geometries at substrates,and construct the 2DMSI database.For the 2D charged building block database,1208 entries from bulk material database are identified.Information of crystal structure,valence state,source,dimension and so on is provided for each entry with a json format.We also show its application in designing and searching for new functional layered materials.The 2DMSI database,building block database,and designed layered materials are available in Science Data Bank at https://doi.org/10.57760/sciencedb.j00113.00188.
文摘It is a major challenge for the airframe-inlet design of modern combat aircrafts,as the flow and electromagnetic wave propagation in the inlet of stealth aircraft are very complex.In this study,an aerodynamic/stealth optimization design method for an S-duct inlet is proposed.The upwind scheme is introduced to the aerodynamic adjoint equation to resolve the shock wave and flow separation.The multilevel fast multipole algorithm(MLFMA)is utilized for the stealth adjoint equation.A dorsal S-duct inlet of flying wing layout is optimized to improve the aerodynamic and stealth characteristics.Both the aerodynamic and stealth characteristics of the inlet are effectively improved.Finally,the optimization results are analyzed,and it shows that the main contradiction between aerodynamic characteristics and stealth characteristics is the centerline and crosssectional area.The S-duct is smoothed,and the cross-sectional area is increased to improve the aerodynamic characteristics,while it is completely opposite for the stealth design.The radar cross section(RCS)is reduced by phase cancelation for low frequency conditions.The method is suitable for the aerodynamic/stealth design of the aircraft airframe-inlet system.
基金supported by the National Natural Science Foundation of China(No.82003561).
文摘Objective Thrombotic thrombocytopenic purpura(TTP)is a rare and fatal disease caused by a severe deficiency in the metalloprotease ADAMTS13 and is characterized by thrombotic microangiopathy.The present study aimed to investigate the genes and variants associated with TTP in a Chinese population.Methods Target sequencing was performed on 220 genes related to complements,coagulation factors,platelets,fibrinolytic,endothelial,inflammatory,and anticoagulation systems in 207 TTP patients and 574 controls.Subsequently,logistic regression analysis was carried out to identify the TTP-associated genes based on the counts of rare deleterious variants in the region of a certain gene.Moreover,the associations between common variants and TTP were also investigated.Results ADAMTS13 was the only TTP-associated gene(OR=3.77;95%CI:1.82–7.81;P=3.6×10^(-4))containing rare deleterious variants in TTP patients.Among these 8 variants,5 novel rare variants that might contribute to TTP were identified,including rs200594025,rs782492477,c.T1928G(p.I643S),c.3336_3361del(p.Q1114Afs*20),and c.3469_3470del(p.A1158Sfs*17).No common variants associated with TTP were identified under the stringent criteria of correction for multiple testing.Conclusion ADAMTS13 is the primary gene related to TTP.The genetic variants associated with the occurrence of TTP were slightly different between the Chinese and European populations.
基金supported in part by the National Natural Science Foundation of China under Grants 62273272 and 61873277in part by the Chinese Postdoctoral Science Foundation under Grant 2020M673446+1 种基金in part by the Key Research and Development Program of Shaanxi Province under Grant 2023-YBGY-243in part by the Youth Innovation Team of Shaanxi Universities.
文摘Currently,the video captioning models based on an encoder-decoder mainly rely on a single video input source.The contents of video captioning are limited since few studies employed external corpus information to guide the generation of video captioning,which is not conducive to the accurate descrip-tion and understanding of video content.To address this issue,a novel video captioning method guided by a sentence retrieval generation network(ED-SRG)is proposed in this paper.First,a ResNeXt network model,an efficient convolutional network for online video understanding(ECO)model,and a long short-term memory(LSTM)network model are integrated to construct an encoder-decoder,which is utilized to extract the 2D features,3D features,and object features of video data respectively.These features are decoded to generate textual sentences that conform to video content for sentence retrieval.Then,a sentence-transformer network model is employed to retrieve different sentences in an external corpus that are semantically similar to the above textual sentences.The candidate sentences are screened out through similarity measurement.Finally,a novel GPT-2 network model is constructed based on GPT-2 network structure.The model introduces a designed random selector to randomly select predicted words with a high probability in the corpus,which is used to guide and generate textual sentences that are more in line with human natural language expressions.The proposed method in this paper is compared with several existing works by experiments.The results show that the indicators BLEU-4,CIDEr,ROUGE_L,and METEOR are improved by 3.1%,1.3%,0.3%,and 1.5%on a public dataset MSVD and 1.3%,0.5%,0.2%,1.9%on a public dataset MSR-VTT respectively.It can be seen that the proposed method in this paper can generate video captioning with richer semantics than several state-of-the-art approaches.
基金financially supported by the Beijing Municipal Science and Technology Project (Grant No. Z231100006023015)the Major Scientific and Technological Research and Development of Shunyi District of Beijingthe Chinese Academy of Sciences。
文摘Silicon carbide(SiC) is a promising platform for fabricating high-voltage, high-frequency and high-temperature electronic devices such as metal oxide semiconductor field effect transistors in which many junctions or interfaces are involved. The work function(WF) plays an essential role in these devices. However, studies of the effect of conductive type and polar surfaces on the WF of SiC are limited. Here, we report the measurement of WFs of Si-and C-terminated polar surfaces for both p-type and n-type conductive 4H-SiC single crystals by scanning Kelvin probe microscopy(SKPFM). The results show that p-type SiC exhibits a higher WF than n-type SiC.The WF of a C-terminated polar surface is higher than that of a Si-terminated polar surface, which is further confirmed by first-principles calculations. By revealing this long-standing knowledge gap, our work facilitates the fabrication and development of SiC-based electronic devices, which have tremendous potential applications in electric vehicles, photovoltaics, and so on. This work also shows that SKPFM is a good method for identifying polar surfaces of SiC and other polar materials nondestructively, quickly and conveniently.
文摘By analyzing the factors which affect the wall-plug efficiency of semiconductor Laser Diodes (LDs), a high efficiency 1060 nm LD was designed, including active region, waveguide layers, and cladding layers. The simulation result shows that the component of In in InGaAs in the active region cannot be too small, otherwise the thickness of InGaAs active layer will exceed the critical thickness, meanwhile the asymmetric large optical cavity can decrease the cavity loss effectively. The epitaxial structure was grown by MOCVD, experimental results of varying cavity length showed that the internal quantum efficiency reached 98.57%, and the cavity loss was only 0.273 cm?1. Devices with 4 mm-cavity-length and 100 μm-strip-width were fabricated, 47.4% wall-plug efficiency was reached under QCW pulse condition at room temperature, and the peak wavelength was 1059.4 nm.
文摘This paper is focused on a 940 nm edge type of semiconductor laser, which is made from 940 nm InGaAs double-quantum-well epitaxial wafer, produced by Metal Organic Chemical Vapor Deposition (MOCVD). In the absence of coating, the efficiency at the room temperature is 0.89 W/A, and the averaged threshold current is 0.307 A. The present study investigates the impact of temperature on the P-I curve, V-I curve and the centre wavelength, the temperature ranging from 286.15 - 333.15 K. It shows that the threshold current increases from 0.28 A to 0.41 A with the increasing temperature. The increase rate is 0.0027 A/K. With the temperature ranging from 286.15 - 333.15 K, the characteristic temperature is calculated to be 120 K. At driven current of 2 A, the output power decreases from 1.47 W to 1.27 W at a rate of 0.00425 W/K. At a constant voltage, the output current initially increases with the temperature within a certain range, beyond which the impact of the temperature is minimum. The ideal factor obtained from V-I curve by curve fitting is 1.076. The series resistance is 0.609 Ω. The centre wavelength shifts to a longer wavelength with the increasing temperature at a rate of 0.275288 nm/K.
基金financially supported by the National Natural Science Foundation of China(Grant No.41230311)the National Science and Technology Support Program(Grant No.2011BAB04B09)+1 种基金the Geological Investigation Work Project of China Geological Survey(Grant No.12120114034901)111 Project of China(Grant No.B07011)
文摘The Jiaodong gold deposits are currently the most important gold resources（with Au reserves of〉4000 t） in China,and the leading gold-producing country globally（with Au production of ～428 t in2013）.Jiaodong is also considered as perhaps the only world-class to giant gold accumulation on the planet where relatively young gold ores（ca.130-120 Ma） were deposited in rocks that are 2 Ga older.The Xincheng world-class high-grade gold deposit,with a proven reserve of 〉200 t gold,is one of the largest deposits in the giant gold province of the Jiaodong Peninsula.It is located in the northwestern part of the jiaobei Uplift,and hosted by ca.132-123 Ma Xincheng quartz monzonites and monzogranites.Ore zones are structurally controlled by the NE-trending and NW-dipping Jiaojia Fault and subsidiary faults,and are mainly restricted to the footwall of the fault.The dominant disseminated- and stockworkstyle ores are associated with strong sericitization,silicification,sulfidation and K-feldspathization,and minor carbonate wallrock alteration halos.The four mineralization stages are pyrite-quartz-sericite（stage 1）,quartz-pyrite（stage 2）,quartz-polysulfide（stage 3） and quartz-carbonate（stage 4）.Gold occurs dominantly as electrum,with lesser amounts of sulfide-hosted native gold and rare native silver and argentite,normally associated with pyrite,chalcopyrite,galena and sphalerite：the latter with proven resources of about 105 t Ag,713 t Cu,and 5100 t S.There are three types of ore-related fluid inclusions：type 1 aqueous-carbonate（H2O-CO2）,type 2aqueous（liquid H2O＋vapor H2O）,and type 3 CO2（liquid CO2 and vapor CO2） inclusions.Homogenization temperatures range from 221 to 304℃ for type 1 inclusions,with salinities of 2.4-13.3 wt.%NaCl eq.,and bulk densities of 0.858-1.022 g/cm～3.The δ～（34）S（CDT） values of hydrothermal sulfides are 4.3-10.6‰and δ～（18）O values of hydrothermal quartz have a median value of 13.0‰.δD values of fluid inclusions in hydrothermal quartz have a median value of-75‰.Calculated δ～（18）Owater has a median value of 5.2‰.The timing of gold mineralization at the Xincheng gold deposit is younger than 123±1 Ma,and likely between 120.9 and 119.9 Ma.A minerals system genetic model for the probable epizonal orogenic Xincheng deposit suggests an initial medium temperature,CO2-rich,and low salinity H2O-CO2 deeply sourced metamorphic ore fluid associated with dehydration and decarbonization of subducting Paleo-Pacific lithosphere.The Jiaojia Fault constrained the migration of ore-forming fluids and metals at the brittle-ductile transition.Fluid immiscibility,caused by episodic pressure drops,led to significant high-grade gold deposition in the giant Xincheng gold deposit.
文摘AIM To assess daclatasvir plus asunaprevir(d UAL) in treatment-na?ve patients from China's Mainland, Russia and South Korea with hepatitis C virus(HCV) genotype 1 b infection. METHODS Patients were randomly assigned(3:1) to receive 24 wk of treatment with d UAL(daclatasvir 60 mg once daily and asunaprevir 100 mg twice daily) beginning on day 1 of the treatment period(immediate treatment arm) or following 12 wk of matching placebo(placebodeferred treatment arm). The primary endpoint was a comparison of sustained virologic response at posttreatment week 12(SVR12) compared with the historical SVR rate for peg-interferon plus ribavirin(70%) among patients in the immediate treatment arm. The first 12 wk of the study were blinded. Safety was assessed in d UAL-treated patients compared with placebo patients during the first 12 wk(doubleblind phase), and during 24 wk of d UAL in both arms combined.RESULTS In total, 207 patients were randomly assigned to immediate(n = 155) or placebo-deferred(n = 52) treatment. Most patients were Asian(86%), female(59%) and aged < 65 years(90%). Among them, 13% had cirrhosis, 32% had IL28 B non-CC genotypes and 53% had baseline HCV RNA levels of ≥ 6 million IU/m L. Among patients in the immediate treatment arm, SVR12 was achieved by 92%(95% confidence interval: 87.2-96.0), which was significantly higher than the historical comparator rate(70%). SVR12 was largely unaffected by cirrhosis(89%), age ≥ 65 years(92%), male sex(90%), baseline HCV RNA ≥ 6 million(89%) or IL28 B non-CC genotypes(96%), although SVR12 was higher among patients without(96%) than among those with(53%) baseline NS5 A resistanceassociated polymorphisms(at L31 or Y93 H). during the double-blind phase, aminotransferase elevations were more common among placebo recipients than among patients receiving d UAL. during 24 wk of d UAL therapy(combined arms), the most common adverse events(≥ 10%) were elevated alanine aminotransferase and upper respiratory tract infection; emergent grade 3-4 laboratory abnormalities were infrequently observed, and all grade 3-4 aminotransferase abnormalities(alanine aminotransferase, n = 9; aspartate transaminase, n = 6) reversed within 8-11 d. Two patients discontinued d UAL treatment; one due to aminotransferase elevations, nausea, and jaundice and the other due to a fatal adverse event unrelated to treatment. There were no treatment-related deaths.CONCLUSION d UAL was well-tolerated during this phase 3 study, and SVR12 with d UAL treatment(92%) exceeded thehistorical SVR rate for peg-interferon plus ribavirin of 70%.
基金jointly supported by the National Key Research and Development Project of China (Grant No.2016YFC0600307)the National Key Basic Research Development Program (973 Program+1 种基金 Grant No.2015CB452606)the fundamental research funds of university teachers(No.53200959708 and No.2-9-2018-126)
文摘Orogenic disseminated and Carlin gold deposits share much similarity in alteration and mineralization.The disseminated orogenic Zhenyuan Au deposit along the Ailaoshan shear zone,southeastern Tibet,was selected to clarify their difference.The alteration and mineralization from the different lithologies,including meta-quartz sandstone,carbonaceous slate,meta-(ultra)mafic rock,quartz porphyry and lamprophyre were researched.According to the mineral assemblage and replacement relationship in all types of host rocks,two reactions show general control on gold deposition:(1) replacement of earlier magnetite by pyrite and carbonaceous material;(2) alteration of biotite and phlogopite phenocrysts in quartz porphyry and lamprophyre into dolomite/ankerite and sericite.Despite the lamprophyre is volumetrically minor and much less fractured than other host rocks,it contains a large portion of Au reserve,indicating that the chemically active lithology has played a more important role in gold precipitation compared to structure.LA-ICP-MS analysis shows that Au mainly occurs as invisible gold in fine-grained pyrite disseminated in the host rocks,with Au content reaching to 258.95 ppm.The diagenetic core of pyrite in meta-quartz sandstone enriched in Co,Ni,Mo,Ag and Hg is wrapped by hydrothermal pyrite enriched in Cu,As,Sb,Au,Tl,Pb and Bi.Different host rock lithology has much impact on the alteration and mineralization features.Carbonate and sericite in altered lamprophyre show they have higher Mg than those developed in other of host rocks denoting that the carbonate and sericite incorporated Mg from phlogopite phenocrysts in the primary lamprophyre during alteration.The ore fluid activated the diagenetic pyrite in meta-quartz sandstone leading the hydrothermal pyrite enriched in Cu,Mo,Ag,Sb,Te,Hg,Tl,Pb and Bi,but the hydrothermal pyrite in meta-(ultra)mafic rock is enriched in Co and Ni as the meta-(ultra)mafic rock host rock contain high content of Co and Ni.However,Au and As shear similar range in both types of host rocks indicating that these two elements most likely come from the deep source fluid rather than the host rocks.It was shown in the disseminated orogenic gold deposit that similar hydrothermal alteration with mineral assemblage of carbonate (mainly dolomite and ankerite),sericite,pyrite and arsenopyrite develops in all types of host rocks.This is different from the Nevada Carlin type,in which alteration is mainly dissolution and silicification of carbonate host rock.On the other hand,Au mainly occur as invisible gold in both disseminated orogenic and Carlin gold deposits.
基金partly funded by the National Key Research Program of China(2019YFA0708603)the National Natural Science Foundation of China(42130801,41230311,41572069,41702070)+2 种基金the 111 Project of the Ministry of Science and Technology,China(BP0719021)the MOST Special Fund from the State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences(MSFGPMR201804)the Key Laboratory of Gold Mineralization Processes and Resource Utilization Subordinated to the Ministry of Natural Resources and Key Laboratory of Metallogenic Geological Process and Resources Utilization in Shandong Province,Shandong Institute of Geological Sciences(KFKT201801,KFKT201802)。
文摘The current margins of the North China and Yangtze Cratons provide arguably the best examples globally of anomalously high mineral endowment within a 100 km buffer zone,hosting 66 diverse world-class to giant ore systems that help explain China’s premier position as a producer of multiple metal and mineral commodities.After the cratonization of these crustal blocks during the Neoarchean-Paleoproterozoic,with incorporation of iron ores on assembled micro-block margins,the margins of the cratons experienced multiple convergence and rifting events leading to metasomatism and fertilization of their underlying sub-continental lithospheric mantle.The rifted margins with trans-lithosphere faults provided pathways for Cu-Au(Mo-W-Sn)-bearing felsic to Ni-Cu-bearing ultrabasic intrusions and REE-rich carbonatite magmas,and for the development of marginal sedimentary basins with both Cu-Pb-Zn-rich source units and reactive carbonate or carbonaceous host rocks.There was diachronous formation of hydrothermal orogenic gold,antimony,and bismuth systems in the narrow orogenic belts between the cratons.Complexity in the Mesozoic Paleo-Pacific subduction systems resulted in asthenosphere upwelling and lithosphere extension and thinning in the North China Craton,leading to anomalous heat flow and formation of orogenic gold deposits,including those of the giant Jiaodong gold province on its north-eastern margin.These gold deposits,many of which formed from fluids liberated by devolatilization of previously metasomatized sub-continental lithospheric mantle,helped propel China to be the premier gold producer globally.The thick sub-continental lithospheric mantle of the cold buoyant cratons helped the preservation of some of the world’s oldest porphyry-skarn and epithermal mineral systems.Although craton margins globally control the formation and preservation of a diverse range of mineral deposits,China represents the premier example in terms of metal endowment due to the anomalous length of its craton margins combined with their abnormally complex tectonic history.
文摘In this study,we used plasma factor V activity and parameters of the thrombin generation test to discuss their diagnostic and prognostic value for disseminated intravascular coagulation (DIC) in patients with hematological malignancies.A total of 164 patients who were diagnosed with hematological malignancies in the Department of Hematology,Union Hospital,between Apr 2014 and Dec.2014 were enrolled in this study.There were 131 patients in the study group and 33 patients in the control group in terms of the laboratory results for DIC.The patients in the study group were divided into a DIC subgroup (n=59) and a non-DIC subgroup (n=72) based on the International Society of Thrombosis and Hemostasis (ISTH) Integral System,and they were divided into four subgroups [score ≤3 (n=35),score=4 (n=37),score=5 (n=47),and score >6 (n=12)] according to ISTH scores.Using 28-day mortality as the endpoint,the patients in the study group were divided into a survival subgroup (n=111) and a non-survival subgroup (n=20).The results showed that the plasma factor V activity was significantly weaker,and lag time and time to peak were significantly shorter in the study group than in the control group (P<0.01).The factor V activity,peak and endogenous thrombin potential (ETP) were significantly decreased in the DIC subgroup as compared with those in the non-DIC subgroup (P<0.01).Among factor V activity,lag time,peak,ETP,and ttPeak,only the factor V activity was significantly decreased in the nonsurvival subgroup compared with the survival subgroup (P<0.01).With the increase in ISTH score,the ETP and peak decreased gradually.The binary logistic regression analysis revealed that PLT,D-dimer,factor V activity and ETP had linear relationship with DIC diagnosed by ISTH Integral System.Using DIC diagnosed by ISTH Integral System as the endpoint,the area under curve (AUC) of factor V activity was found to be similar to that of blood platelet count (PLT) and prothrombin time (PT).In conclusion,factor V activity,ETP and peak had diagnostic value for DIC in patients with hematological malignancies,and only factor V activity had limited prognostic value.
基金This work was supported by the National Natural Science Foundation of China (Nos. 5157-4139 and 5180-4247)De Montfort University through its distinguished Vice-Chancellor 2020 ProgrammeUK Science and Technology Facilities Council (STFC) through Batteries Early Career Researcher Award.
文摘In underground mines, high air temperatures in the summer months lead to an increase in inlet airflow temperatures. This leads to seasonal thermal pollution in the mines. This paper examines the dynamics and effects of seasonal variation in surface air temperatures and surrounding rock temperatures in deep coal mines. It also examines temperature variations in the main ventilation circuit, working face, and surrounding rock. The study results revealed that airflow temperatures were significantly affected by seasonal air temperature variations. The greater the distance was between the inlet and the wellhead of the ventilation shaft, the less the effect was on temperature. Moreover, slight temperature variations (1.0-3.0 ℃) were observed between various points on the return route during the summer months. Airflow temperatures along the airflow inlet to the return route of the working face first decreased, but then increased. The temperature field of the surrounding rock increased gradually with increased distance between the mine roadway and inlet, with recorded rock temperatures as high as 40.53 ℃. The radius of the heat-adjusting layer was between 28 and 33 m.
基金supported by the National Key Research and Development Project of China(2016YFC0600307)the National Key Basic Research Development Program(973 Program+3 种基金2015CB452606)the Chinese Post-doctoral Innovative Talent Support Program(BX20180280)the China Postdoctoral Science Foundation(2018M641428)the 111 Project of the Ministry of Science and Technology(BP0719021).
文摘The gold deposits in the Youjiang basin,totaling>25 Moz gold,have traditionally been thought to be of Carlin-type,particularly those with extensional structural geometries in the northern basin dominated by platform sedimentary sequences.However,the structural geometries,mineralization styles and alteration types for the Jinya,Gaolong and Nakuang gold deposits in the south-central part of the basin are remarkably similar to those of unequivocal orogenic gold deposits.Structural studies show that gold mineralization in the three gold deposits was controlled by tight“locked-up”anticlines with NW−SE-to E−W-trending and/or concomitant thrusts and/or shear zones,which resulted from NE−SW-to N–S-trending compression or transpression following the Early Triassic closure of the Paleo-Tethyan Ocean.Alteration zones in these deposits are dominated by silicification(quartz),sericitization,sulfidation and carbonation.Zoned pyrites in these deposits comprise Au-poor cores and invisible Au-bearing rims with minor external free gold.Euhedral to subhedral auriferous arsenopyrites also contribute to the gold budget.These features indicate that the three gold deposits are sediment-hosted orogenic gold deposits that contrast markedly with the Carlin-type gold deposits in the northern part of the Youjiang basin in terms of structural geometry and timing,mineralization style and nature of associated alteration.Although additional reliable ages using robust methodologies are still required,the older isotopic ages of the gold deposits in the south-central Youjiang basin are also consistent with earlier formation during transpression that predated extension during orogenic collapse,the period of formation of the Carlin-type gold deposits in the northern Youjiang basin.
基金financially supported by the Major Research Project of National Natural Science Foundation of China(NSFC ProjectGrant Nos.92162215 and 92155305)+2 种基金National Key Basic Research Development Program of China(973 ProgramGrant Nos.2015CB452602 and 2015CB452606)111 Plan under the Ministry of Education of China and the State Administration of Foreign Experts Affairs,China(Grant No.B07011)。
文摘Magmatic-hydrothermal Sn deposits are commonly associated with high silica magmas,but why most global high silica granites do not bear economic Sn ore grades remains unclear.Two crucial factors controlling magmatic-hydrothermal Sn mineralization,including advanced fractionation and depressurization-induced rapid cooling,were revealed in the case study of the Guyong granitic pluton linked with the Xiaolonghe Sn deposit,in the Tengchong block,SW China.The Guyong granitic pluton comprises three petrological facies:less evolved biotite syenogranite,evolved alkali granite and leucogranite,and highly evolved facies(the protolith of greisenized granite).Similar crystallization ages(~77 Ma)and gradual contact between different petrological facies indicate the Guyong granitic pluton records a continuous fractionation process.Monte Carlo-revised Rayleigh fractionation model suggests the fractionation degree of the Guyong pluton is markedly high(>87 wt.%)that can only be achieved by a high initial water(≥4 wt.%)content in the parent granitic magma revealed by rhyolite-MELTS calculation.Advanced degree fractionation causes the first Sn enrichment but it also significantly increases the viscosity of evolved magmas,suppressing the exsolution and transport of hydrothermal fluids.Hence,it must be compensated by the second critical factor:depressurization-induced rapid cooling,reflected by the occurrence of highly metamict zircons in the greisenized granite.The highly metamict feature,indicated by the large full width at half maximum(FWHM)values of zirconν3(SiO_(4)) peak(>19.5 cm^(-1)),suggests these zircons do not experience thermal annealing but rapidly ascend into a shallow cooling environment.Depressurization-induced rapid cooling facilitates exsolution and transport of hydrothermal fluids,interacting with wall rocks and resulting in Sn mineralization.
