Existing conventional megajoule plasma focus machines with 2–3 MA are producing fusion neutron yields of several times 10^(11) in deuterium operation,the fusion yields predominantly being the beam-gas target.Increasi...Existing conventional megajoule plasma focus machines with 2–3 MA are producing fusion neutron yields of several times 10^(11) in deuterium operation,the fusion yields predominantly being the beam-gas target.Increasing the current to 10 MA and using 50%–50%D-T mixture will scale the neutron yield towards 10^(16) D-T fusion neutrons.In this work,we derive the Lawson criterion for plasma focus devices with a beam-target fusion neutron mechanism,so that we may glimpse what future technological advancements are needed for a break-even Q=1 plasma focus.We perform numerical experiments with a present-day feasible 0.9 MV,8.1 MJ,11 MA machine operating in 100 Torr in 50%–50%D-T mixture.The Lee Code simulation gives a detailed description of the plasma focus dynamics through each phase,and provides plasma and yield parameters which show that out of 1.1×10^(19) fast beam ions produced in the plasma focus pinch,only 1.24×10^(14) ions take part in beam-target fusion reactions within the pinch,producing the same number of D-T neutrons.The remnant beam ions,numbering at least 10^(19),exit the focus pinch at 1.9 MeV,which is far above the 115 keV ion energy necessary for an optimum beam-target cross-section.We propose to regain the lost fusion rates by using a high-pressure D-T-filled drift-tube to attenuate the energy of the remnant beam ions until they reach the energy for the optimum fusion cross-section.Such a fusion enhancement tube would further harvest beam-target fusion reactions by increasing the interaction path length(1 m)at increased interaction density(6 atm).A gain factor of 300 is conservatively estimated,with a final yield of 3.7×10^(16) D-T neutrons carrying kinetic energy of 83.6 kJ,demonstrating Q=0.01.展开更多
1.Objective The Eastern Junggar Kalamaili region in Xinjiang constitutes a significant tin metallogenic belt in northwest China(Fig.1a).It hosts four independent tin deposits-Kamusite,Ganliangzi,Beilekuduke,and Saresh...1.Objective The Eastern Junggar Kalamaili region in Xinjiang constitutes a significant tin metallogenic belt in northwest China(Fig.1a).It hosts four independent tin deposits-Kamusite,Ganliangzi,Beilekuduke,and Sareshenke-from west to east,supplemented by two tin mineralized points,namely Hongtujingzi and Sujiquan(Figs.1b).according to the ore type and the composition of gangue minerals,the tin deposits in the region are classified into two groups:Quartz vein type and greisen type,with the Sareshenke deposit ascribed to the former and the remainder to the latter.展开更多
This study examines the intricate occurrences of thermal and solutal Marangoni convection in three-layered flows of viscous fluids,with a particular emphasis on their relevance to renewable energy systems.This researc...This study examines the intricate occurrences of thermal and solutal Marangoni convection in three-layered flows of viscous fluids,with a particular emphasis on their relevance to renewable energy systems.This research examines the flow of a three-layered viscous fluid,considering the combined influence of heat and solutal buoyancy driven Rayleigh-Bénard convection,as well as thermal and solutal Marangoni convection.The homotopy perturbation method is used to examine and simulate complex fluid flow and transport phenomena,providing important understanding of the fundamental physics and assisting in the optimization of various battery configurations.The inquiry examines the primary elements that influence Marangoni convection and its impact on battery performance,providing insights on possible enhancements in energy storage devices.The findings indicate that the velocity profiles shown graphically exhibit a prominent core zone characterized by the maximum speed,which progressively decreases as it approaches the walls of the channel.This study enhances our comprehension of fluid dynamics and the transmission of heat and mass in intricate systems,which has substantial ramifications for the advancement of sustainable energy solutions.展开更多
利用大体积进样技术(large vo lum e in jec tion,LVI),结合气相色谱-质谱方法对二英的测定效果进行了研究。同时与传统分流/不分流进样技术进行了对比。对进样体积为1,5,10,25,50和100μL的色谱图进行了分析。研究表明使用大体积进样方...利用大体积进样技术(large vo lum e in jec tion,LVI),结合气相色谱-质谱方法对二英的测定效果进行了研究。同时与传统分流/不分流进样技术进行了对比。对进样体积为1,5,10,25,50和100μL的色谱图进行了分析。研究表明使用大体积进样方式,在不影响色谱分离度的同时,大幅度提高了分析灵敏度。通过对土壤样品的检测,证明该方法可以用于环境样品的实际测定。展开更多
Objective Mafic magmas can form in different tectonic settings with various geochemical characteristics depending on their mantle sources. Basalts generated in back-arc basins provide valuable perspectives on mantle s...Objective Mafic magmas can form in different tectonic settings with various geochemical characteristics depending on their mantle sources. Basalts generated in back-arc basins provide valuable perspectives on mantle structure and composition, on controls for melt generation, and on the sources responsible for arc magma genesis.展开更多
Objective Eclogites are important indicators of ancient plate boundaries or paleosuture zones. Despite their great geological significance, very few investigations have been carried out in the Kunlun region. The Centr...Objective Eclogites are important indicators of ancient plate boundaries or paleosuture zones. Despite their great geological significance, very few investigations have been carried out in the Kunlun region. The Central East Kunlun fault zone was believed to be an Early Paleozoic suture zone, but there has been no reliable evidence for this, though studies on ophiolite, granite, and basic granulite indicate that the Early Paleozoic orogeny occurred in the East Kunlun. This work focused on the Dagele eclogites in Central East Kunlun to provide new constraints for the Central East Kunlun suture zone.展开更多
Climate change,urbanization,and population increase limit food availability.To sustain human existence,there is the need to increase food and agricultural production to mitigate the impact of these factors.Scientists ...Climate change,urbanization,and population increase limit food availability.To sustain human existence,there is the need to increase food and agricultural production to mitigate the impact of these factors.Scientists have been working for years on ways to increase food production.From plant breeding techniques to soil science,scientists have made tremendous progress.The rhizobiome has been proven to be important to crop production,and the impact of the rhizobiome on plant health cannot be overemphasized.Being rich in diverse complex microbial interactions,the rhizosphere has become a major force in recent plant growth promotion studies.The upsurge in next-generation sequencing applications with the various“omics”technologies is helping to unearth information relating to rhizosphere impact on plant growth.Explaining the complex interactions between and across microbial species present in the rhizosphere is important to further enhance our understanding of their mechanistic and mutualistic functions.Knowledge from this can be used in rhizosphere biome engineering for improved plant growth and yield in the face of the various biotic and abiotic challenges.展开更多
The Mayuan stratabound Pb-Zn deposit in Nanzheng,Shaanxi Province,is located in the northern margin of the Yangtze Plate,in the southern margin of the Beiba Arch.The orebodies are stratiform and hosted in breciated do...The Mayuan stratabound Pb-Zn deposit in Nanzheng,Shaanxi Province,is located in the northern margin of the Yangtze Plate,in the southern margin of the Beiba Arch.The orebodies are stratiform and hosted in breciated dolostone of the Sinian Dengying Formation.The ore minerals are primarily sphalerite and galena,and the gangue minerals comprise of dolomite,quartz,barite,calcite and solid bitumen.Fluid inclusions from ore-stage quartz and calcite have homogenization tempreatures from 98 to 337℃ and salinities from 7.7 wt%to 22.2 wt%（NaCl equiv.）.The vapor phase of the inclusions is mainly composed of CH_4 with minor CO_2 and H_2S.The δD_（fluid） values of fluid inclusions in quartz and calcite display a range from-68‰ to-113‰（SMOW）,and the δ^（18）O_（fluid）values calculated from δ^（18）O_（quartz） and δ^（18）O_（calcite） values range from 4.5‰ to 16.7‰（SMOW）.These data suggest that the ore-forming fluids may have been derived from evaporitic sea water that had reacted with organic matter.The δ^（13）C_（CH4） values of CH_4 in fluid inclusions range from-37.2‰ to-21.0‰（PDB）,suggesting that the CH_4 in the ore-forming fluids was mainly derived from organic matter.This,together with the abundance of solid bitumen in the ores,suggest that organic matter played an important role in mineralization,and that the thermochemical sulfate reduction（TSR） was the main mechanism of sulfide precipitation.The Mayuan Pb-Zn deposit is a carbonate-hosted epigenetic deposit that may be classified as a Mississippi Valley type（MVT） deposit.展开更多
Field investigation combined with detailed petrographic observation indicate that abundant oil,gas,and solid bitumen inclusions were entrapped in veins and cements of sedimentary rocks in the Dabashan foreland,which w...Field investigation combined with detailed petrographic observation indicate that abundant oil,gas,and solid bitumen inclusions were entrapped in veins and cements of sedimentary rocks in the Dabashan foreland,which were used to reconstruct the oil and gas migration history in the context of tectonic evolution.Three stages of veins were recognized and related to the collision between the North China block and the Yangtze block during the Indosinian orogeny from Late Triassic to Early Jurassic（Dl）,the southwest thrusting of the Qinling orogenic belt towards the Sichuan basin during the Yanshanian orogeny from Late Jurassic to Early Cretaceous（D2）,and extensional tectonics during Late Cretaceous to Paleogene（D3）,respectively.The occurrences of hydrocarbon inclusions in these veins and their homogenization temperatures suggest that oil was generated in the early stage of tectonic evolution,and gas was generated later,whereas solid bitumen was the result of pyrolysis of previously accumulated hydrocarbons.Three stages of hydrocarbon fluid inclusions were also identified in cements of carbonates and sandstones of gas beds in the Dabashan foreland belt and the Dabashan foreland depression（northeastern Sichuan basin）,which recorded oil/gas formation,migration,accumulation and destruction of paleo-reservoirs during the D2.Isotopic analysis of hydrocarbon fluid inclusions contained in vein minerals shows that δ^（13）C_1 of gas in fluid inclusions ranges from-17.0‰ to-30.4‰（PDB） and δD from-107.7‰ to-156.7‰（SMOW）,which indicates that the gas captured in the veins was migrated natural gas which may be correlated with gas from the gas-fields in northern Sichuan basin.Organic geochemical comparison between bitumen and potential source rocks indicates that the Lower Cambrian black shale and the Lower Permian black limestone were the most possible source rocks of the bitumen.Combined with tectonic evolution history of the Dabashan foreland,the results of this study suggest that oil was generated from the Paleozoic source rocks in the Dabashan area under normal burial thermal conditions before Indosinian tectonics and accumulated to form paleo-reservoirs during Indosinian collision between the North China block and the Yangtz block.The paleo-reservoirs were destroyed during the Yanshanian tectonic movement when the Dabashan foreland was formed.At the same time,oil in the paleo-reservoirs in the Dabashan foreland depression was pyrolyzed to transform to dry gas and the residues became solid bitumen.展开更多
Rapid and precise vehicle recognition and classification are essential for intelligent transportation systems,and road target detection is one of the most difficult tasks in the field of computer vision.The challenge ...Rapid and precise vehicle recognition and classification are essential for intelligent transportation systems,and road target detection is one of the most difficult tasks in the field of computer vision.The challenge in real-time road target detection is the ability to properly pinpoint relatively small vehicles in complicated environments.However,because road targets are prone to complicated backgrounds and sparse features,it is challenging to detect and identify vehicle kinds fast and reliably.We suggest a new vehicle detection model called MEB-YOLO,which combines Mosaic and MixUp data augmentation,Efficient Channel Attention(ECA)attention mechanism,Bidirectional Feature Pyramid Network(BiFPN)with You Only Look Once(YOLO)model,to overcome this problem.Four sections make up this model:Input,Backbone,Neck,and Prediction.First,to improve the detection dataset and strengthen the network,MixUp and Mosaic data improvement are used during the picture processing step.Second,an attention mechanism is introduced to the backbone network,which is Cross Stage Par-tial Darknet(CSPDarknet),to reduce the influence of irrelevant features in images.Third,to achieve more sophisticated feature fusion without increasing computing cost,the BiFPN structure is utilized to build the Neck network of the model.The final prediction results are then obtained using Decoupled Head.Experiments demonstrate that the proposed model outperforms several already available detection methods and delivers good detection results on the University at Albany DEtection and TRACking(UA-DETRAC)public dataset.It also enables effective vehicle detection on real traffic monitoring data.As a result,this technique is efficient for detecting road targets.展开更多
Maikhanellids are a distinct group of Cambrian Fortunian small shelly fossils by the capshaped profiles and scaly shell ornamentation.According to the individual shell shape and ornamentation feature types of 50 maikh...Maikhanellids are a distinct group of Cambrian Fortunian small shelly fossils by the capshaped profiles and scaly shell ornamentation.According to the individual shell shape and ornamentation feature types of 50 maikhanellids fossils which were collected from Xixiang botia,we confirmed the family Maikhanellidae content of six genera,which are Maikhanella,Ramenta,Purella,Ramentoides,Yunnannopleura and Mediata.Unlike the halkieriid animals whose shells and spicules are articulated on different body parts,maikhanellids were presumably yielded by siphogonuchitid spicules penetrating the intermediate matrix(the"spicule shell"hypothesis),and this is the reason that some researchers treated maikhanellids and co-occurring siphogonuchitids as synonyms.The affinities of Maikhanellids and siphogonuchitids remain debatable.Here,we report three dimensionally phosphatized maikhanellid shells and siphogonuchitid spicule bundles from the Cambrian Fortunian small shell faunas of South China.They differ from all the previously reported maikhanellids and siphogonuchitids,and may represent new types.The intact and smooth surface underneath the partially preserved scales of the shells challenges the"spicule-shell"hypothesis.The present siphogonuchitid spicules differ from the maikhanellid scales in size,morphology,and.arrangement pattern,thus the spicules might not be derived from the shells.Whether the shells and spicule bundles were articulated on different body parts of the same animals remains unknown.展开更多
Nb-enriched arc basalts,an extremely special rock type,were formed in a specific tectonic setting,which have attracted much attention in recent years.Although Nbenriched basalts in the Yining Block were interpreted as...Nb-enriched arc basalts,an extremely special rock type,were formed in a specific tectonic setting,which have attracted much attention in recent years.Although Nbenriched basalts in the Yining Block were interpreted as arc-affinity basalts,some geologists suggested that they should be Nb-enriched continental basalts and not arcrelated.Recently,the Nb-enriched arc basalts have been first identified from the Dahalajunshan Formation in southern Wusunshan,Yining.展开更多
The effect of microwave treatment on the tensile properties of treated sugar palm fibre with 6% NaOH reinforced thermoplastic polyurethane composites was investigated. Firstly, the sugar palm fibres were treated by 6%...The effect of microwave treatment on the tensile properties of treated sugar palm fibre with 6% NaOH reinforced thermoplastic polyurethane composites was investigated. Firstly, the sugar palm fibres were treated by 6% alkali solution. Then, microwave treatment was used to treat the alkali treated sugar palm fibres. Three types of temperatures(i.e. 70, 80 and 90℃) were applied in microwave treatment. The extruder and hot press machines were used to mixing the sugar palm fibres and polyurethane resin, and fabricate the composites. Tensile properties(i.e. tensile strength, tensile modulus and elongation at break) were studied by following the ASTM D-638 standard. The highest tensile strength was recorded 18.42 MPa with microwave temperature at 70℃ and 6% alkali pre-treatment. Therefore, the temperature 70℃ of microwave treatment may consider the best degree cent grate.展开更多
The Qushi’ang granodiorite(QSG)is located at the central east of the ophiolitic melange belt in the East Kunlun Orogenic Belt(EKOB)in the northern margin of the Qinghai-Tibetan Plateau.LA-MC-ICP-MS zircon U–Pb datin...The Qushi’ang granodiorite(QSG)is located at the central east of the ophiolitic melange belt in the East Kunlun Orogenic Belt(EKOB)in the northern margin of the Qinghai-Tibetan Plateau.LA-MC-ICP-MS zircon U–Pb dating suggests that the granodiorite and mafic microgranular enclaves(MMEs)crystallized 246.61±0.62 and 245.45±0.9 Ma ago,respectively.Granodiorite,porphyritic diorite,and MMEs are metaluminous and medium-K calk-alkaline series,with island-arc magma features,such as LILE enrichment and HFSE depletion.The porphyritic diorite has high Cr(13.50 ppm to 59.01 ppm),Ni(228.53 ppm to 261.29 ppm),and Mg~#(46–54).Granodiorite and porphyritic diorite have similar mineral compositions and evolved major and trace elements contents,particularly Cr and Ni,both of which are significantly higher than that in granites of the same period.The crystallization age of MMEs is close to that of granodiorite,and their major and trace elements contents are in-between porphyritic diorite and granodiorite.The results suggest that the original mafic magma,which was the product of mantle melting by subduction process,intruded into the lower crust(Kuhai Rock Group),resulting in the formation of granodiorite.Countinous intrusion of mafic magma into the unconsolidated granodiorite formed MMEs and porphyritic diorite.The granodiorite reformed by late-stage strike-slip faulting tectonic event indicates that the strike-slip fault of Middle Kunlun and the collision of the Bayanhar block with East Kunlun were later than 246 Ma.Therefore,the formation of the QSG not only indicates the critical period of evolution of East Kunlun but also represents the tectonic transition from oceanic crust subduction to slab breaking.展开更多
Qinling orogen is one of the five main repository distribution provinces of large scale graphite resources. Graphite occurrence strata are multitudinous including NeoArchaean group to Neopaleozoic. Mineral deposit typ...Qinling orogen is one of the five main repository distribution provinces of large scale graphite resources. Graphite occurrence strata are multitudinous including NeoArchaean group to Neopaleozoic. Mineral deposit types are complete consisting of crystal flaky graphite deposit and aphanitic graphite deposit, ore types of the former are main graphite gneiss, graphite schist and graphitized marble, and ore types of the latter are main graphite layer metamorphosised from coal bed and graphitic carbargilite. At present, most graphite deposits with low research degree only implement preliminary investigations of the graphite resource, which has a good prospect. Based on the basic material of dozens of graphite deposits, spots and plays discovered in the Qinling orogen, this paper applied geologic multidisciplinary analysis method to disclose the graphite deposit types of the Qinling orogen, mainly through outdoors geologic survey and specimen examination with analysis of some typical deposits： regional metamorphism crystal graphite deposits and thermo-contact metamorphic aphanitic graphite deposits, with the control of latitudinally trending regional tectonic, graphite deposits of the Qinling orogen distribute sublatitudinally trending three large ore belts： I the Neoarchean-Proterozoic basement crystal graphite enrichment deposits zone along the south margin of North China plate; II the Carboniferous intermountain basin group aphanitic graphite enrichment deposits zone near the Shangdan suture of the West Qinling; III Paleozoic crystal graphite enrichment deposits zone in the Qinling paleomicroplate of the west part of the East Qinling.Conclusions are reached from multiple inquiries： Qinling multi-cycle complex continental collision orogen zone has experienced multiple tectonic framework transformation and polyphase tectonic thermal event from NeoArchean Erathem adjointing multiple graphite tectonic mineralization cycle. In the light of chief control of mineralization and ore types, each of the three large graphite deposits belts of the Qinling orogen has its own genesis： I graphite deposits enriched metallogenetic zone is that regional tectogenetic movement from NeoArchaean caused polyphase metapepsis, which superimposed up and reconstructed NeoArchean Erathem to Proterozoic basement, forming regional metamorphic big flake crystal graphite deposits; I! graphite deposits enriched metallogenetic zone is that polyphase regional tectogenetic movement associated with multiple heating caused by multiphase igneous intrusion, which resulted in original coal layers emerging multiple thermo-contact metamorphisms and formed thermo-contact metamorphic aphanitic graphite deposits. III graphite deposits enriched metallogenetic zone is that Palaeozoic cap- rock experienced polyphase metapepsis, forming regional metamorphic finely flake crystal graphite deposits. Cemprehensive research of metallogenetic mechanism in graphite deposits and its associated profitable deposits of the Qinling orogen is importance for future exploration.展开更多
Recently,through implementation of the National Nature Science Foundation of China （No.41303027） and Special Fund for Basic Scientific Research of Central Colleges （310827153506,310827153407,2014G1271058）,we focus...Recently,through implementation of the National Nature Science Foundation of China （No.41303027） and Special Fund for Basic Scientific Research of Central Colleges （310827153506,310827153407,2014G1271058）,we focused on basalts in Darbut and Karamay ophiolitic melanges in West Junggar which is a part of the Central Asian Orogenic Belt,and made some advances as follows.展开更多
The Xingdi mafic-ultramafic intrusions occur in the northeastern margin of the Tarim craton. The Xingdi No. 3 intrusion is the smallest of four intrusions, with an exposed area of 1.7 km2, and the zircon U-Pb age of t...The Xingdi mafic-ultramafic intrusions occur in the northeastern margin of the Tarim craton. The Xingdi No. 3 intrusion is the smallest of four intrusions, with an exposed area of 1.7 km2, and the zircon U-Pb age of the intrusion is 752±4 Ma. The intrusion consists of gabbros, pyroxenites and peridotites, and exhibits a crystallization sequence of the main rock-forming minerals as olivine, orthopyroxene, clinopyroxene and plagioclase. Mineralization occurred at or near the boundaries of the intrusion between pyroxenites and peridotites, and appears as a layered or lenticular shape about 500 m long and 4–15 m wide. The primary sulfides have a relatively simple mineralogy dominated by pyrrhotite-pentlandite-chalcopyrite assemblages, which occur as droplet, star-like and graphic texture and locally sideronitic structures. Geochronological and geochemistry investigations suggest that the Xingdi mafic-ultramafic intrusions and coeval volcanic rock in the Kuluktag area of the Tarim craton formed in an intracontinental breakup environment. Based on the composition of the dominant rockforming minerals and covariant relationships of other oxides versus Mg O, the parental magma of the Xingdi No.3 intrusion belongs to high-Mg tholeiitic basaltic magmas with Mg O of 10.78 wt%. The Xingdi No.3 intrusive rocks are characterized by light REE enrichment relative to heavy REE, negative Nb-Ta anomalies, low 143Nd/144Nd ratios（from 0.511183 to 0.511793） and high initial 87Sr/86Sr ratios（from 0.7051 to 0.7113）. The magma was derived from the enriched-lithospheric mantle and was contaminated during emplacement. According to rock assemblages, mineralization, olivine characteristics, geochemical characteristics and mass balance, there are better copper-nickel ore prospects in the Xingdi No.3 intrusion than in the other three intrusions in the area.展开更多
Accurate and reliable river flow information is critical to planning and management for sustainable water resources utilization. Most of engineering activities related to hydrologic designs, flood, drought, reservoirs...Accurate and reliable river flow information is critical to planning and management for sustainable water resources utilization. Most of engineering activities related to hydrologic designs, flood, drought, reservoirs and their operations are heavily dependent on the river flow information derived from river rating curve. The rating curve for a given river section is normally developed from a set of direct stage-discharge measurements for different periods. This involves considerable labour, risk and resources, and presupposes a complex and extensive measuring survey. Extrapolating the rating curve beyond the measured range, as common in many cases, is fraught with errors and uncertainties, due to the complex hydraulic behaviour of the surface water profile in transition from section, channel, downstream and flood plain controls which are often poorly understood with direct measurements. Hydraulic modeling has recently emerged as one of the more promising methods to efficiently develop accurate rating curves for a river section with simple or complex hydraulic structures and conditions. This paper explores the use of a Hydraulic Engineering Center-River Analysis System (HEC-RAS) model to review and develop river rating curves for three hydrometric stations on two rivers in Kwale, coastal Kenya. The HEC-RAS models were set up based on topographical (cross section and longitudinal) survey data for the reaches and engineering drawings for the hydraulic structures commonly used as section controls for flow measurement. The model was calibrated under unsteady state conditions against measured stage-discharge data which were captured using a Velocity Current Meter (Valeport) and an Acoustic Doppler Current Profiler (ADCP) for both low and high flow. The rating curves were extracted from model results and the uncertainty associated with each rating curve analyzed. The results obtained by the HEC-RAS model were satisfactory and deemed acceptable for predicting discharge across the stage range at each river section.展开更多
1.Objective The West Kunlun in Xinjiang is located on the northwestern margin of the Qinghai-Tibet Plateau(Fig.1a)and at the junction of the Paleo-Asian tectonic domain and the Tethys tectonic domain.It serves as an i...1.Objective The West Kunlun in Xinjiang is located on the northwestern margin of the Qinghai-Tibet Plateau(Fig.1a)and at the junction of the Paleo-Asian tectonic domain and the Tethys tectonic domain.It serves as an important area for the study on the geologic evolution of the Karakorum-West Kunlun due to its special tectonic position.展开更多
文摘Existing conventional megajoule plasma focus machines with 2–3 MA are producing fusion neutron yields of several times 10^(11) in deuterium operation,the fusion yields predominantly being the beam-gas target.Increasing the current to 10 MA and using 50%–50%D-T mixture will scale the neutron yield towards 10^(16) D-T fusion neutrons.In this work,we derive the Lawson criterion for plasma focus devices with a beam-target fusion neutron mechanism,so that we may glimpse what future technological advancements are needed for a break-even Q=1 plasma focus.We perform numerical experiments with a present-day feasible 0.9 MV,8.1 MJ,11 MA machine operating in 100 Torr in 50%–50%D-T mixture.The Lee Code simulation gives a detailed description of the plasma focus dynamics through each phase,and provides plasma and yield parameters which show that out of 1.1×10^(19) fast beam ions produced in the plasma focus pinch,only 1.24×10^(14) ions take part in beam-target fusion reactions within the pinch,producing the same number of D-T neutrons.The remnant beam ions,numbering at least 10^(19),exit the focus pinch at 1.9 MeV,which is far above the 115 keV ion energy necessary for an optimum beam-target cross-section.We propose to regain the lost fusion rates by using a high-pressure D-T-filled drift-tube to attenuate the energy of the remnant beam ions until they reach the energy for the optimum fusion cross-section.Such a fusion enhancement tube would further harvest beam-target fusion reactions by increasing the interaction path length(1 m)at increased interaction density(6 atm).A gain factor of 300 is conservatively estimated,with a final yield of 3.7×10^(16) D-T neutrons carrying kinetic energy of 83.6 kJ,demonstrating Q=0.01.
基金supported by the National Key R&D Program of China(No.2021YFC2901802)project of the China Geological Survey(No.DD20240073)Key R&D Program of Shaanxi Province(No.2024GH-ZDXM-26).
文摘1.Objective The Eastern Junggar Kalamaili region in Xinjiang constitutes a significant tin metallogenic belt in northwest China(Fig.1a).It hosts four independent tin deposits-Kamusite,Ganliangzi,Beilekuduke,and Sareshenke-from west to east,supplemented by two tin mineralized points,namely Hongtujingzi and Sujiquan(Figs.1b).according to the ore type and the composition of gangue minerals,the tin deposits in the region are classified into two groups:Quartz vein type and greisen type,with the Sareshenke deposit ascribed to the former and the remainder to the latter.
基金Project(52276068)supported by the National Natural Science Foundation of China。
文摘This study examines the intricate occurrences of thermal and solutal Marangoni convection in three-layered flows of viscous fluids,with a particular emphasis on their relevance to renewable energy systems.This research examines the flow of a three-layered viscous fluid,considering the combined influence of heat and solutal buoyancy driven Rayleigh-Bénard convection,as well as thermal and solutal Marangoni convection.The homotopy perturbation method is used to examine and simulate complex fluid flow and transport phenomena,providing important understanding of the fundamental physics and assisting in the optimization of various battery configurations.The inquiry examines the primary elements that influence Marangoni convection and its impact on battery performance,providing insights on possible enhancements in energy storage devices.The findings indicate that the velocity profiles shown graphically exhibit a prominent core zone characterized by the maximum speed,which progressively decreases as it approaches the walls of the channel.This study enhances our comprehension of fluid dynamics and the transmission of heat and mass in intricate systems,which has substantial ramifications for the advancement of sustainable energy solutions.
文摘利用大体积进样技术(large vo lum e in jec tion,LVI),结合气相色谱-质谱方法对二英的测定效果进行了研究。同时与传统分流/不分流进样技术进行了对比。对进样体积为1,5,10,25,50和100μL的色谱图进行了分析。研究表明使用大体积进样方式,在不影响色谱分离度的同时,大幅度提高了分析灵敏度。通过对土壤样品的检测,证明该方法可以用于环境样品的实际测定。
基金supported by the Sub Project of "National Key Research and Development Plan of China"-"Study on the Distribution Rule of Tianshan-Altai Bulk Minerals and Evaluation of Deep Resource Potential" (grant No. 2018YFC0604001)the Xinjiang Geological Exploration Fund (grant No. A16-1-LQ14)the National Natural Science Foundation of China (grants No. 41273033 and 41303027)
文摘Objective Mafic magmas can form in different tectonic settings with various geochemical characteristics depending on their mantle sources. Basalts generated in back-arc basins provide valuable perspectives on mantle structure and composition, on controls for melt generation, and on the sources responsible for arc magma genesis.
基金co-supported by the National Natural Science Foundation of China(grant No.41302070)the Fundamental Research Funds for the Central Universities (grants No.310827172004 and 310827173401)Geological Exploration Fund Project of Qinghai Province (grant No.2012209)
文摘Objective Eclogites are important indicators of ancient plate boundaries or paleosuture zones. Despite their great geological significance, very few investigations have been carried out in the Kunlun region. The Central East Kunlun fault zone was believed to be an Early Paleozoic suture zone, but there has been no reliable evidence for this, though studies on ophiolite, granite, and basic granulite indicate that the Early Paleozoic orogeny occurred in the East Kunlun. This work focused on the Dagele eclogites in Central East Kunlun to provide new constraints for the Central East Kunlun suture zone.
基金funded by the National Research Foundation(NRF)of South Africa(UID123634 and UID132595)which was granted to Olubukola O.Babalola。
文摘Climate change,urbanization,and population increase limit food availability.To sustain human existence,there is the need to increase food and agricultural production to mitigate the impact of these factors.Scientists have been working for years on ways to increase food production.From plant breeding techniques to soil science,scientists have made tremendous progress.The rhizobiome has been proven to be important to crop production,and the impact of the rhizobiome on plant health cannot be overemphasized.Being rich in diverse complex microbial interactions,the rhizosphere has become a major force in recent plant growth promotion studies.The upsurge in next-generation sequencing applications with the various“omics”technologies is helping to unearth information relating to rhizosphere impact on plant growth.Explaining the complex interactions between and across microbial species present in the rhizosphere is important to further enhance our understanding of their mechanistic and mutualistic functions.Knowledge from this can be used in rhizosphere biome engineering for improved plant growth and yield in the face of the various biotic and abiotic challenges.
基金granted by the China State Mineral Resources Investigation Program(Grant No. 1212011121117)the National Natural Science Foudation of China(Grant No.41102050)the Central University Fund(310827153407)
文摘The Mayuan stratabound Pb-Zn deposit in Nanzheng,Shaanxi Province,is located in the northern margin of the Yangtze Plate,in the southern margin of the Beiba Arch.The orebodies are stratiform and hosted in breciated dolostone of the Sinian Dengying Formation.The ore minerals are primarily sphalerite and galena,and the gangue minerals comprise of dolomite,quartz,barite,calcite and solid bitumen.Fluid inclusions from ore-stage quartz and calcite have homogenization tempreatures from 98 to 337℃ and salinities from 7.7 wt%to 22.2 wt%（NaCl equiv.）.The vapor phase of the inclusions is mainly composed of CH_4 with minor CO_2 and H_2S.The δD_（fluid） values of fluid inclusions in quartz and calcite display a range from-68‰ to-113‰（SMOW）,and the δ^（18）O_（fluid）values calculated from δ^（18）O_（quartz） and δ^（18）O_（calcite） values range from 4.5‰ to 16.7‰（SMOW）.These data suggest that the ore-forming fluids may have been derived from evaporitic sea water that had reacted with organic matter.The δ^（13）C_（CH4） values of CH_4 in fluid inclusions range from-37.2‰ to-21.0‰（PDB）,suggesting that the CH_4 in the ore-forming fluids was mainly derived from organic matter.This,together with the abundance of solid bitumen in the ores,suggest that organic matter played an important role in mineralization,and that the thermochemical sulfate reduction（TSR） was the main mechanism of sulfide precipitation.The Mayuan Pb-Zn deposit is a carbonate-hosted epigenetic deposit that may be classified as a Mississippi Valley type（MVT） deposit.
基金funded by CNSF(No.41173055)the Research Program of China Geological Survey(No. 1212011121117)
文摘Field investigation combined with detailed petrographic observation indicate that abundant oil,gas,and solid bitumen inclusions were entrapped in veins and cements of sedimentary rocks in the Dabashan foreland,which were used to reconstruct the oil and gas migration history in the context of tectonic evolution.Three stages of veins were recognized and related to the collision between the North China block and the Yangtze block during the Indosinian orogeny from Late Triassic to Early Jurassic（Dl）,the southwest thrusting of the Qinling orogenic belt towards the Sichuan basin during the Yanshanian orogeny from Late Jurassic to Early Cretaceous（D2）,and extensional tectonics during Late Cretaceous to Paleogene（D3）,respectively.The occurrences of hydrocarbon inclusions in these veins and their homogenization temperatures suggest that oil was generated in the early stage of tectonic evolution,and gas was generated later,whereas solid bitumen was the result of pyrolysis of previously accumulated hydrocarbons.Three stages of hydrocarbon fluid inclusions were also identified in cements of carbonates and sandstones of gas beds in the Dabashan foreland belt and the Dabashan foreland depression（northeastern Sichuan basin）,which recorded oil/gas formation,migration,accumulation and destruction of paleo-reservoirs during the D2.Isotopic analysis of hydrocarbon fluid inclusions contained in vein minerals shows that δ^（13）C_1 of gas in fluid inclusions ranges from-17.0‰ to-30.4‰（PDB） and δD from-107.7‰ to-156.7‰（SMOW）,which indicates that the gas captured in the veins was migrated natural gas which may be correlated with gas from the gas-fields in northern Sichuan basin.Organic geochemical comparison between bitumen and potential source rocks indicates that the Lower Cambrian black shale and the Lower Permian black limestone were the most possible source rocks of the bitumen.Combined with tectonic evolution history of the Dabashan foreland,the results of this study suggest that oil was generated from the Paleozoic source rocks in the Dabashan area under normal burial thermal conditions before Indosinian tectonics and accumulated to form paleo-reservoirs during Indosinian collision between the North China block and the Yangtz block.The paleo-reservoirs were destroyed during the Yanshanian tectonic movement when the Dabashan foreland was formed.At the same time,oil in the paleo-reservoirs in the Dabashan foreland depression was pyrolyzed to transform to dry gas and the residues became solid bitumen.
基金funded by the National Natural Science Foundation of China(NSFC)(No.61170110)Zhejiang Provincial Natural Science Foundation of China(LY13F020043).
文摘Rapid and precise vehicle recognition and classification are essential for intelligent transportation systems,and road target detection is one of the most difficult tasks in the field of computer vision.The challenge in real-time road target detection is the ability to properly pinpoint relatively small vehicles in complicated environments.However,because road targets are prone to complicated backgrounds and sparse features,it is challenging to detect and identify vehicle kinds fast and reliably.We suggest a new vehicle detection model called MEB-YOLO,which combines Mosaic and MixUp data augmentation,Efficient Channel Attention(ECA)attention mechanism,Bidirectional Feature Pyramid Network(BiFPN)with You Only Look Once(YOLO)model,to overcome this problem.Four sections make up this model:Input,Backbone,Neck,and Prediction.First,to improve the detection dataset and strengthen the network,MixUp and Mosaic data improvement are used during the picture processing step.Second,an attention mechanism is introduced to the backbone network,which is Cross Stage Par-tial Darknet(CSPDarknet),to reduce the influence of irrelevant features in images.Third,to achieve more sophisticated feature fusion without increasing computing cost,the BiFPN structure is utilized to build the Neck network of the model.The final prediction results are then obtained using Decoupled Head.Experiments demonstrate that the proposed model outperforms several already available detection methods and delivers good detection results on the University at Albany DEtection and TRACking(UA-DETRAC)public dataset.It also enables effective vehicle detection on real traffic monitoring data.As a result,this technique is efficient for detecting road targets.
基金supported by the National Natural Science Foundation of China(41572009,41572007,41472015)College Students'Innovative Entrepreneurial Training Program of Chang'an University(Grant No.201610710043,201610710044,201610710047,201610710045),0012-310600161000The Tenth"Challenge Cup"Competition of Chang'an University(C-P-B-2,C-P-B-6,C-P-B-8)
文摘Maikhanellids are a distinct group of Cambrian Fortunian small shelly fossils by the capshaped profiles and scaly shell ornamentation.According to the individual shell shape and ornamentation feature types of 50 maikhanellids fossils which were collected from Xixiang botia,we confirmed the family Maikhanellidae content of six genera,which are Maikhanella,Ramenta,Purella,Ramentoides,Yunnannopleura and Mediata.Unlike the halkieriid animals whose shells and spicules are articulated on different body parts,maikhanellids were presumably yielded by siphogonuchitid spicules penetrating the intermediate matrix(the"spicule shell"hypothesis),and this is the reason that some researchers treated maikhanellids and co-occurring siphogonuchitids as synonyms.The affinities of Maikhanellids and siphogonuchitids remain debatable.Here,we report three dimensionally phosphatized maikhanellid shells and siphogonuchitid spicule bundles from the Cambrian Fortunian small shell faunas of South China.They differ from all the previously reported maikhanellids and siphogonuchitids,and may represent new types.The intact and smooth surface underneath the partially preserved scales of the shells challenges the"spicule-shell"hypothesis.The present siphogonuchitid spicules differ from the maikhanellid scales in size,morphology,and.arrangement pattern,thus the spicules might not be derived from the shells.Whether the shells and spicule bundles were articulated on different body parts of the same animals remains unknown.
基金supported by the National Natural Science Foundation of China(Grant No.41273033)
文摘Nb-enriched arc basalts,an extremely special rock type,were formed in a specific tectonic setting,which have attracted much attention in recent years.Although Nbenriched basalts in the Yining Block were interpreted as arc-affinity basalts,some geologists suggested that they should be Nb-enriched continental basalts and not arcrelated.Recently,the Nb-enriched arc basalts have been first identified from the Dahalajunshan Formation in southern Wusunshan,Yining.
文摘The effect of microwave treatment on the tensile properties of treated sugar palm fibre with 6% NaOH reinforced thermoplastic polyurethane composites was investigated. Firstly, the sugar palm fibres were treated by 6% alkali solution. Then, microwave treatment was used to treat the alkali treated sugar palm fibres. Three types of temperatures(i.e. 70, 80 and 90℃) were applied in microwave treatment. The extruder and hot press machines were used to mixing the sugar palm fibres and polyurethane resin, and fabricate the composites. Tensile properties(i.e. tensile strength, tensile modulus and elongation at break) were studied by following the ASTM D-638 standard. The highest tensile strength was recorded 18.42 MPa with microwave temperature at 70℃ and 6% alkali pre-treatment. Therefore, the temperature 70℃ of microwave treatment may consider the best degree cent grate.
基金jointly supported by the National Science Foundation of China(Grant No.,41472191,41502191,41172186,40972136)the Special Fund for Basic Scientific Research of Central Colleages,Chang'an University(Grant Nos.310827161002,310827161006)the Commonweal Geological Survey,the Aluminum Corporation of China and the Land-Resources Department of Qinghai Province(Grant No.,200801)
文摘The Qushi’ang granodiorite(QSG)is located at the central east of the ophiolitic melange belt in the East Kunlun Orogenic Belt(EKOB)in the northern margin of the Qinghai-Tibetan Plateau.LA-MC-ICP-MS zircon U–Pb dating suggests that the granodiorite and mafic microgranular enclaves(MMEs)crystallized 246.61±0.62 and 245.45±0.9 Ma ago,respectively.Granodiorite,porphyritic diorite,and MMEs are metaluminous and medium-K calk-alkaline series,with island-arc magma features,such as LILE enrichment and HFSE depletion.The porphyritic diorite has high Cr(13.50 ppm to 59.01 ppm),Ni(228.53 ppm to 261.29 ppm),and Mg~#(46–54).Granodiorite and porphyritic diorite have similar mineral compositions and evolved major and trace elements contents,particularly Cr and Ni,both of which are significantly higher than that in granites of the same period.The crystallization age of MMEs is close to that of granodiorite,and their major and trace elements contents are in-between porphyritic diorite and granodiorite.The results suggest that the original mafic magma,which was the product of mantle melting by subduction process,intruded into the lower crust(Kuhai Rock Group),resulting in the formation of granodiorite.Countinous intrusion of mafic magma into the unconsolidated granodiorite formed MMEs and porphyritic diorite.The granodiorite reformed by late-stage strike-slip faulting tectonic event indicates that the strike-slip fault of Middle Kunlun and the collision of the Bayanhar block with East Kunlun were later than 246 Ma.Therefore,the formation of the QSG not only indicates the critical period of evolution of East Kunlun but also represents the tectonic transition from oceanic crust subduction to slab breaking.
基金financially supported by National Natural Science Foundation of China (NO.41390451 and NO.41172101)Science and technology research projects of China Coal Geological Bureau (2013-I-03)basic geological survey project of China Geological Survey (12120114083001)
文摘Qinling orogen is one of the five main repository distribution provinces of large scale graphite resources. Graphite occurrence strata are multitudinous including NeoArchaean group to Neopaleozoic. Mineral deposit types are complete consisting of crystal flaky graphite deposit and aphanitic graphite deposit, ore types of the former are main graphite gneiss, graphite schist and graphitized marble, and ore types of the latter are main graphite layer metamorphosised from coal bed and graphitic carbargilite. At present, most graphite deposits with low research degree only implement preliminary investigations of the graphite resource, which has a good prospect. Based on the basic material of dozens of graphite deposits, spots and plays discovered in the Qinling orogen, this paper applied geologic multidisciplinary analysis method to disclose the graphite deposit types of the Qinling orogen, mainly through outdoors geologic survey and specimen examination with analysis of some typical deposits： regional metamorphism crystal graphite deposits and thermo-contact metamorphic aphanitic graphite deposits, with the control of latitudinally trending regional tectonic, graphite deposits of the Qinling orogen distribute sublatitudinally trending three large ore belts： I the Neoarchean-Proterozoic basement crystal graphite enrichment deposits zone along the south margin of North China plate; II the Carboniferous intermountain basin group aphanitic graphite enrichment deposits zone near the Shangdan suture of the West Qinling; III Paleozoic crystal graphite enrichment deposits zone in the Qinling paleomicroplate of the west part of the East Qinling.Conclusions are reached from multiple inquiries： Qinling multi-cycle complex continental collision orogen zone has experienced multiple tectonic framework transformation and polyphase tectonic thermal event from NeoArchean Erathem adjointing multiple graphite tectonic mineralization cycle. In the light of chief control of mineralization and ore types, each of the three large graphite deposits belts of the Qinling orogen has its own genesis： I graphite deposits enriched metallogenetic zone is that regional tectogenetic movement from NeoArchaean caused polyphase metapepsis, which superimposed up and reconstructed NeoArchean Erathem to Proterozoic basement, forming regional metamorphic big flake crystal graphite deposits; I! graphite deposits enriched metallogenetic zone is that polyphase regional tectogenetic movement associated with multiple heating caused by multiphase igneous intrusion, which resulted in original coal layers emerging multiple thermo-contact metamorphisms and formed thermo-contact metamorphic aphanitic graphite deposits. III graphite deposits enriched metallogenetic zone is that Palaeozoic cap- rock experienced polyphase metapepsis, forming regional metamorphic finely flake crystal graphite deposits. Cemprehensive research of metallogenetic mechanism in graphite deposits and its associated profitable deposits of the Qinling orogen is importance for future exploration.
文摘Recently,through implementation of the National Nature Science Foundation of China （No.41303027） and Special Fund for Basic Scientific Research of Central Colleges （310827153506,310827153407,2014G1271058）,we focused on basalts in Darbut and Karamay ophiolitic melanges in West Junggar which is a part of the Central Asian Orogenic Belt,and made some advances as follows.
基金supported by the National Natural Science Foundation of China(Grant No.41302070)the Fundamental Research Funds for the Central Universities(310827173401,310827153407)China Regional Geological Survey(12120113043100)
文摘The Xingdi mafic-ultramafic intrusions occur in the northeastern margin of the Tarim craton. The Xingdi No. 3 intrusion is the smallest of four intrusions, with an exposed area of 1.7 km2, and the zircon U-Pb age of the intrusion is 752±4 Ma. The intrusion consists of gabbros, pyroxenites and peridotites, and exhibits a crystallization sequence of the main rock-forming minerals as olivine, orthopyroxene, clinopyroxene and plagioclase. Mineralization occurred at or near the boundaries of the intrusion between pyroxenites and peridotites, and appears as a layered or lenticular shape about 500 m long and 4–15 m wide. The primary sulfides have a relatively simple mineralogy dominated by pyrrhotite-pentlandite-chalcopyrite assemblages, which occur as droplet, star-like and graphic texture and locally sideronitic structures. Geochronological and geochemistry investigations suggest that the Xingdi mafic-ultramafic intrusions and coeval volcanic rock in the Kuluktag area of the Tarim craton formed in an intracontinental breakup environment. Based on the composition of the dominant rockforming minerals and covariant relationships of other oxides versus Mg O, the parental magma of the Xingdi No.3 intrusion belongs to high-Mg tholeiitic basaltic magmas with Mg O of 10.78 wt%. The Xingdi No.3 intrusive rocks are characterized by light REE enrichment relative to heavy REE, negative Nb-Ta anomalies, low 143Nd/144Nd ratios（from 0.511183 to 0.511793） and high initial 87Sr/86Sr ratios（from 0.7051 to 0.7113）. The magma was derived from the enriched-lithospheric mantle and was contaminated during emplacement. According to rock assemblages, mineralization, olivine characteristics, geochemical characteristics and mass balance, there are better copper-nickel ore prospects in the Xingdi No.3 intrusion than in the other three intrusions in the area.
文摘Accurate and reliable river flow information is critical to planning and management for sustainable water resources utilization. Most of engineering activities related to hydrologic designs, flood, drought, reservoirs and their operations are heavily dependent on the river flow information derived from river rating curve. The rating curve for a given river section is normally developed from a set of direct stage-discharge measurements for different periods. This involves considerable labour, risk and resources, and presupposes a complex and extensive measuring survey. Extrapolating the rating curve beyond the measured range, as common in many cases, is fraught with errors and uncertainties, due to the complex hydraulic behaviour of the surface water profile in transition from section, channel, downstream and flood plain controls which are often poorly understood with direct measurements. Hydraulic modeling has recently emerged as one of the more promising methods to efficiently develop accurate rating curves for a river section with simple or complex hydraulic structures and conditions. This paper explores the use of a Hydraulic Engineering Center-River Analysis System (HEC-RAS) model to review and develop river rating curves for three hydrometric stations on two rivers in Kwale, coastal Kenya. The HEC-RAS models were set up based on topographical (cross section and longitudinal) survey data for the reaches and engineering drawings for the hydraulic structures commonly used as section controls for flow measurement. The model was calibrated under unsteady state conditions against measured stage-discharge data which were captured using a Velocity Current Meter (Valeport) and an Acoustic Doppler Current Profiler (ADCP) for both low and high flow. The rating curves were extracted from model results and the uncertainty associated with each rating curve analyzed. The results obtained by the HEC-RAS model were satisfactory and deemed acceptable for predicting discharge across the stage range at each river section.
基金supported by the National Science Foundation of China(41302051)the Natural Science Foundation of Shaanxi Province(2020JM-311)the project of China Geological Survey(DD20221636,DD20221691)。
文摘1.Objective The West Kunlun in Xinjiang is located on the northwestern margin of the Qinghai-Tibet Plateau(Fig.1a)and at the junction of the Paleo-Asian tectonic domain and the Tethys tectonic domain.It serves as an important area for the study on the geologic evolution of the Karakorum-West Kunlun due to its special tectonic position.
