Accumulation mechanism of mantle-derived helium resources in petroliferous basins, eastern China

A series of marginal-sea basins and fault-depression basins were formed in eastern China under the background of subduction of the West Pacific plate.Different types of helium-rich natural gas reservoirs(He>1000 ppm,1 ppm=1μmol mol^(-1))have been found in these basins:helium-rich CO_(2)gas reservoirs,helium-rich N_(2)gas reservoirs,and helium-rich hydrocarbon gas reservoirs.Based on the analysis of gas geochemical data,the source and accumulation mechanism of helium in these heliumrich natural gas reservoirs were discussed.Helium-rich natural gas has relatively high 3He/4He ratios(0.88-4.91 Ra,average 2.82 Ra).The ^(3)He/^(4)He ratio characteristics of mantle xenoliths and mantle-derived CO_(2)gas reservoirs indicate that the helium in these helium-rich natural gas reservoirs is mainly mantle-derived(>70%).The original mantle volatile is mainly CO_(2)with a low helium concentration(He<200 ppm),and the enrichment of mantle-derived helium in the gas reservoir is mainly related to the dissolution and mineralization of CO_(2).During this process,the CO_(2)/3He ratio decreases from 2×10^(9)to approximately 2×10^(6).As CO_(2)dissolves and mineralizes,the concentration of conservative gases(He and N_(2))increases in the remaining CO_(2)gas proportionally to the loss of CO_(2).Large amounts of carbonate minerals,such as dawsonite,which are relatively enriched in 13C,are found in CO_(2)reservoirs in eastern China.The relative enrichment of^(12)C in residual CO_(2)gas is important evidence of the dissolution and mineralization of CO_(2).The relative abundance of mantle-derived helium and N_(2)gas increases thousands of times during the dissolution and mineralization of CO_(2),which is the main accumulation mechanism of mantle-derived helium-rich CO_(2)gas reservoirs and helium-rich N_(2)gas reservoirs.Helium-rich gas from the mantle is mixed with alkane gas generated by organic matter in the sedimentary basin to form helium-rich hydrocarbon gas reservoirs.

Geochemistry on mantle-derived volatiles in natural gases from eastern China oil/gas provinces (I)——A novel helium resource——commercial accumulation of mantle-derived helium in the sedimentary crust

Commercial accumulation of mantle-derived helium in the sedimentary shell is discussed. Generally speaking, a commercial helium pool is formed by accumulated 4He that comes from uranium and thorium via a-decay; therefore, it has a very low He/4He value in the magnitude of 10 . The helium concentration in some gas wells of eastern China oil/gas provinces is about or over 0.05%-0.1%, consequently forming commercial helium wells (pools), such as the Wangjinta Gas Pool in Songliao Basin, Huangqiao Gas Pool in North Jiangsu Basin and some gas wells in Sanshui Basin. Studies have proved that when the 3He/4He value of a helium gas pool is about 3.7×10 -6 -7.2× 10-6, namely mantle-derived helium in its total helium concentration accounts for 33. 5%-65.4%, it is a crust-mantle dual-source or dominantly mantle-derived helium gas pool, which is a novel helium resource and its formation is mainly related to the distribution of megafractures.

Co-doped BaFe_(2)As_(2) Josephson junction fabricated with a focused helium ion beam

Josephson junction plays a key role not only in studying the basic physics of unconventional iron-based superconductors but also in realizing practical application of thin-film based devices,therefore the preparation of high-quality iron pnictide Josephson junctions is of great importance.In this work,we have successfully fabricated Josephson junctions from Co-doped BaFe_(2)As_(2)thin films using a direct junction fabrication technique which utilizes high energy focused helium ion beam(FHIB).The electrical transport properties were investigated for junctions fabricated with various He^(+)irradiation doses.The junctions show sharp superconducting transition around 24 K with a narrow transition width of 2.5 K,and a dose correlated foot-structure resistance which corresponds to the effective tuning of junction properties by He^(+)irradiation.Significant J_c suppression by more than two orders of magnitude can be achieved by increasing the He^(+)irradiation dose,which is advantageous for the realization of low noise ion pnictide thin film devices.Clear Shapiro steps are observed under 10 GHz microwave irradiation.The above results demonstrate the successful fabrication of high quality and controllable Co-doped BaFe_(2)As_(2)Josephson junction with high reproducibility using the FHIB technique,laying the foundation for future investigating the mechanism of iron-based superconductors,and also the further implementation in various superconducting electronic devices.

Helium and Argon Isotopic Composition of Cenozoic Alkali Basalts and Mantle-Derived Xenoliths from Kuandian, Liaoning Province, China

The noble gas isotopic composition and content data of 2 alkali basalts, 3 lherzolite xenoliths and one clinopyroxene megacryst from the Kuandian region have confirmed the occurrence of a fractionation of noble gases during magmatism. Light noble gases such as He and Ne are high in mobility and appear to be incompatible as compared with heavy ones (such as Kr and Xe). Therefore, light noble gases are abundant in volcanics, especially in the volcanics with bubbles; lherzolite xenoliths have relatively high heavy noble gases. The clinopyroxene megacryst has the lowest abundance of noble gases, probably due to its high P-T origin. Noble gas isotopic composition of the clinopyroxene megacryst reveals that the mantle source beneath the Kuandian area has an MORB-like reservoir with 3He/4He ratio of ～10 Ra (Ra: atmospheric 3He/4He ratio) and 40Ar/36Ar ratio of 345.6. The lherzolite xenoliths possess moderate 3He/4He ratios of 2.59-4.53 Ra, reflecting the loss of primary helium during rock deformation or metasomatism caused by enriched mantle fluids during the up-lifting. The alkali volcanics have very low 3He/4He ratios (0.47-0.61 Ra), indicating a contribution of radiogenic 4He, probably having resulted from crust contamination. Most of the samples have excess 21Ne and 22Ne as compared with atmospheric neon, but Kr and Xe isotopic compositions are indistinguishable from atmospheric values within uncertainties with only individual samples having excess 129Xe, 134Xe and 136Xe.

Evolution of helium bubbles in FeCoNiCr-based high-entropy alloys containing γ′ nanoprecipitates

A series of high-entropy alloys(HEAs) containing nanoprecipitates of varying sizes is successfully prepared by a non-consuming vacuum arc melting method.In order to study the irradiation evolution of helium bubbles in the FeCoNiCrbased HE As with γ' precipitates,these samples are irradiated by 100-keV helium ions with a fluence of 5 × 10^(20) ions/m^(2) at 293 K and 673 K,respectively.And the samples irradiated at room temperature are annealed at different temperatures to examine the diffusion behavior of helium bubbles.Transmission electron microscope(TEM) is employed to characterize the structural morphology of precipitated nanoparticles and the evolution of helium bubbles.Experimental results reveal that nanosized,spherical,dispersed,coherent,and ordered L1_(2)-type Ni_(3)Ti γ' precipitations are introduced into FeCoNiCr(Ni_(3)Ti)_(0.1) HEAs by means of ageing treatments at temperatures between 1073 K and 1123 K.Under the ageing treatment conditions adopted in this work,γ' nanoparticles are precipitated in FeCoNiCr(Ni_(3)Ti)_(0.1) HE As,with average diameters of 15.80 nm,37.09 nm,and 62.50 nm,respectively.The average sizes of helium bubbles observed in samples after 673-K irradiation are 1.46 nm,1.65 nm,and 1.58 nm,respectively.The improvement in the irradiation resistance of FeCoNiCr(Ni_(3)Ti)_(0.1) HEAs is evidenced by the diminution in bubbles size.Furthermore,the FeCoNiCr(Ni_(3)Ti)_(0.1) HEAs containing γ' precipitates of 15.8 nm exhibits the minimum size and density of helium bubbles,which can be ascribed to the considerable helium trapping effects of heterogeneous coherent phase boundaries.Subsequently,annealing experiments conducted after 293-K irradiation indicate that HEAs containing precipitated phases exhibits smaller apparent activation energy(E_(a)) for helium bubbles,resulting in larger helium bubble size.This study provides guidance for improving the irradiation resistance of L1_(2)-strengthened high-entropy alloy.

Genetic source,migration and accumulation of helium under deep thermal fluid activities:A case study of Ledong diapir area in Yinggehai Basin,South China Sea

Based on the geochemical parameters and analytical data,the heat conservation equation,mass balance law,Rayleigh fractionation model and other methods were used to quantify the in-situ yield and external flux of crust-derived helium,and the initial He concentration and thermal driving mechanism of mantle-derived helium,in the Ledong Diapir area,the Yinggehai Basin,in order to understand the genetic source,migration and accumulation mechanisms of helium under deep thermal fluid activities.The average content of mantle-derived He is only 0.0014%,the ^(3)He/^(4)He value is(0.002–2.190)×10^(−6),and the R/Ra value ranges from 0.01 to 1.52,indicating the contribution of mantle-derived He is 0.09%–19.84%,while the proportion of crust-derived helium can reach over 80%.Quantitative analysis indicates that the crust-derived helium is dominated by external input,followed by in-situ production,in the Ledong diapir area.The crust-derived helium exhibits an in-situ 4 He yield rate of(7.66–7.95)×10^(−13)cm^(3)/(a·g),an in-situ 4 He yield of(4.10–4.25)×10^(−4)cm^(3)/g,and an external 4 He influx of(5.84–9.06)×10^(−2)cm^(3)/g.These results may be related to atmospheric recharge into formation fluid and deep rock-water interactions.The ratio of initial mole volume of 3 He to enthalpy(W)is(0.004–0.018)×10^(−11) cm^(3)/J,and the heat contribution from the deep mantle(X_(M))accounts for 7.63%–36.18%,indicating that deep hot fluid activities drive the migration of mantle-derived 3 He.The primary helium migration depends on advection,while the secondary migration is controlled by hydrothermal degassing and gas-liquid separation.From deep to shallow layers,the CO_(2/3) He value rises from 1.34×10^(9)to 486×10^(9),indicating large amount of CO_(2)has escaped.Under the influence of deep thermal fluid,helium migration and accumulation mechanisms include:deep heat driven diffusion,advection release,vertical hydrothermal degassing,shallow lateral migration,accumulation in traps far from faults,partial pressure balance and sealing capability.

Atomistic study on the microscopic mechanism of grain boundary embrittlement induced by small dense helium bubbles in iron

The helium bubbles induced by 14 MeV neutron irradiation can cause intergranular fractures in reduced activation ferritic martensitic steel,which is a candidate structural material for fusion reactors.In order to elucidate the susceptibility of different grain boundaries(GBs)to helium-induced embrittlement,the tensile fracture processes of 10 types of GBs with and without helium bubbles in body-centered cubic(bcc)iron at the relevant service temperature of 600 K were investigated via molecular dynamics methods.The results indicate that in the absence of helium bubbles,the GBs studied here can be classified into two distinct categories:brittle GBs and ductile GBs.The atomic scale analysis shows that the plastic deformation of ductile GB at high temperatures originates from complex plastic deformation mechanisms,including the Bain/Burgers path phase transition and deformation twinning,in which the Bain path phase transition is the most dominant plastic deformation mechanism.However,the presence of helium bubbles severely inhibits the plastic deformation channels of the GBs,resulting in a significant decrease in elongation at fractures.For bubble-decorated GBs,the ultimate tensile strength increases with the increase in the misorientation angle.Interestingly,the coherent twin boundary∑3{112}was found to maintain relatively high fracture strength and maximum failure strain under the influence of helium bubbles.

Characteristics and main controlling factors of helium resources in the main petroliferous basins of the North China Craton

At present, the main controlling factors of helium accumulation is one of the key scientific problems restricting the exploration and development of helium reservoir. In this paper, based on the calculation results of He generation rate and the geochemical characteristics of the produced gas, both the similarities and differences between natural gas and He resources in the Bohai Bay, Ordos and the surrounding Songliao Basin are compared and analyzed, discussing the main controlling factors of helium resources in the three main petroliferous basins of the North China Craton. It is found that the three basins of Bohai Bay, Ordos and Songliao have similar characteristics of source rocks, reservoirs and cap rocks, that's why their methane resource characteristics are essentially the same. The calculated ~4He generation per cubic metamorphic crystalline basement in the three basins is roughly equivalent, which is consistent with the measured He resources, and it is believed that the ~4He of radiogenic from the crust is the main factor controlling the overall He accumulation in the three basins;there is almost no contribution of the mantle-derived CH_4, which suggests that the transport and uplift of mantle-derived ~3He carried by the present-day magmatic activities along the deep-large faults is not the main reason for the mantle-derived ~3He mixing in the basins. Combined with the results of regional volcanic and geophysical studies,it is concluded that under the background of the destruction of North China Craton, magma intrusion carried a large amount of mantle-derived material and formed basic volcanic rocks in the Bohai Bay Basin and Songliao Basin, which replenished mantle-derived ~3He for the interior of the basins, and that strong seismic activities in and around the basins also promoted the upward migration of mantle source ~3He. This study suggests that the tectonic zone with dense volcanic rocks in the Cenozoic era and a high incidence of historical strong earthquakes history may be a potential area for helium resource exploration.

Enrichment of Mantle-derived Fluids in the Formation Process of Granitoids: Evidence from the Himalayan Granitoids around Kunjirap in the Western Qinghai-Tibet Plateau

Taking the Himalayan granitoids around Kunjirap in the western Qinghai-Tibetplateau as an example, the authors present in this paper the characteristics of the granitoids richin mantle-derived fluid components and discuss their rock-forming mechanism. The research resultsindicate that the rock assemblage of the studied granitoids involves diopside syenite-diopsidegranite-biotite (monzonitic) granite, consisting mainly of K-feldspar, oligoclase, quartz,iron-phlogolite, diopside and edenite. The rocks are rich in mantle-derived fluid components ofvolatiles including F, alkali metal elements such as K, Na, Rb, Sr and Ha, and radiogenicheat-producing elements such as U and Th. They were generated by the influx of mantle-derived fluidsinto the lower crest to give rise to partial melting during the lithosphere thinning in theQinghai-Tibet plateau.

Gold Content of Mantle-Derived Rocks from Eastern China and Its Implications

We have analyzed the gold content of 65 samples of mantle-derived xenoliths and their host rocks from eastern China, which is found to be inhomogeneous, falling in the ranges of 1.0×109-8.2×109 (averaging 3.8 ×10-9) and 0.2×10-9-5.3×10-9 (averaging 2.7×10-9) in the mantle-derived xenoliths and the host basalts respectively. Except the samples from Wanquan County of Hebei Province and Anding County of Hainan Province, the gold content is the highest on the margins of the North China platform and decreases spatially towards the north and south, and temporally the samples of the Tertiary have a higher gold content than those of the Quaternary. The gold content of the mantle-derived xenoliths and the host Paleozoic kimberlites is 3.8×10-9-180×109and 0.1×10-9-38.0×10-9 respectively, which are higher than that in the mantle-derived xenoliths in basalt and the host Cenozoic basalts. The mantle-derived xenoliths have a higher gold content than the host rocks, but their relativity is not very clear, suggesting that the genetic relationship between them is complex. Our data indicate that the average gold content of the lithospheric mantle in eastern China is approximately equal to or approaching 3.8×10-9, which is lower than the average abundance of the upper mantle (5.0×10-9), higher than the average abundance of the continental crust (3.0×10-9) and only slightly higher than the average abundance of the lower continental crust (3.4×10-9). Except the samples from Hainan Province, the mantle-derived xenoliths in basalts with a high gold content are distributed on the two margins of the North China platform, corresponding to the gold deposits-concentrated districts in northwest Hebei Province and Shandong Province, showing the control by the old continental lithospheric mantle and the lower continental crust on the margins of the North China platform. The gold content of the mantle-derived xenoliths from Hainan Province ranges from 7.1×10-9 to 15×10-9, suggesting that some blocks of the lithospheric mantle in Hainan Province may be derived from the ancient gold-rich lithospheric mantle of western Australia and that Hainan Province may possibly be an important gold deposits-concentrated district. Some mantle-derived xenoliths in kimberlite of Shandong Province have an excessively high gold content amounting to 180×10-9, which provides new evidence for the possibility of 'finding gold deposits near kimberlite pipes or alkali-basalt volcanic vents'. Thererfore, the gold content of the mantle-derived xenoliths may be an indicator to the distribution of gold deposits-concentrated districts.

A Study on the Ore-forming Effect of Mantle-derived Fluid

Based on summarizing of the effect of mantle-derived fluid on the formation of ores, especially on gold ore, and with the latest investigations, such as the formation of ore from the action of shallow-deep fluid, the transportation effect of the thermal energy by mantle-derived fluid, this paper mainly aims at the effect of mantle-derived fluid on the generation of hydrocarbons. With the proof from geochemistry and fluid inclusion, it was suggested that the mantle-derived fluid not only supplied source materials for hydrocarbons, but also supplied essential energy and matter necessary for the generation of hydrocarbons. The mantle-derived fluid had a good effect, but at the same time it had an adverse effect under specific conditions, on the formation of reservoirs. This paper also discusses the future direction and significance of studying mantle-derived fluid.

The Principles for Discrimination of the Source Composition of Mantle-Derived Igneous Rocks and the Nature of the Mantle Source Region of the Emeishan Basalts

This paper discusses the discrimination principles. deduction and methods for probing into the source composition of mantle-derived magma. The magmatophile (incompatible) source elements are not all optimal tracers for mantle source composition. The ratios of two strong magmatophile elements (D<1) or the ratios of two trace elements with the same D value are not controlled by the formation mode and evolution degree of a magma, but maintain the characteristics of their composition in mantle source region prior to the magma formation. The ratios are related to different mantle-crust structures and dynamics. The mantle source composition of the Emeishan Basalt series is similar to that of the South Atlantic Rio Grande Rise-Walvis Ridge Basalts and Brazil continental-margin basalts. This may indicate that these basalt series might have similar source regions and tectonic environments.

The Discovery and Study of Mantle-Derived Dunite Inclusions in Hornblende-Diorite in the Handan-Xingtai Area,Hebei

Phlogopiie-and diopside-bearing dunite occurs as rounded inclusions in hornblende-diorite. Thepetrofabrics, mineral composition and abundances of the trace elements in the dunite indicate that the inclu-sions were derived from the upper mantle and are the residues of high-degree partial melting of mantlepeirdotite. The study of trace elements in the inclusions and their host rocks shows that the magma was origi-nated from the mantle which was enriched in incompatible elements by mantle metasomatism prior to the par-tial melting.

GEOCHEMISTRY AND TECTONIC ENVIRONMENT AND RESERVOIR FORMATION OF MANTLE-DERIVED NATURAL GAS IN THE SONGLIAO BASIN, NORTHEASTERN CHINA

During several decades of exploration, a number of mantle-derived natural gas pools have been discovered in the vicinities of deep faults in the Songliao Basin, northeastern China. The natural gas in these pools has a δ13C1 value of ?16.50/00 to ?24.20/00, a reversed arrangement in the amount of carbon isotopes in methane and its endogamous products (namely, δ13C1 >δ13C2 >δ13C3 >δ13C4), a 3He/4He value of 1.97 to 2.34×10-6,and an Ar/36Ar value of 1063 to 1949. This indicates a mantle 40 source for the natural gas. The trace elements Cd, In, Te and Re, never found in organic-sourced hydrocarbons, are highly enriched in certain crude oils from the Basin; respectively, concentrations of these elements were found to be 751, 28, 16 and 323 times the average crustal values in China, and this also supports a mantle-derived natural gas origin. The characteristics of mantled-derived magmatic rocks, hydrothermal fluids and gaseous fractions distributed in and near the deep Songliao Basin faults indicate that rifting tectonics is providing the mechanisms for this outgassing of the mantle. Deep extensional (normal) faults provide pathways for upward movement of these materials, and in the Songliao Basin, these deep rift fault zones are associated with reservoir occurrence and cap rock seals, forming good sites for accumulation of mantle-derived natural gas. Furthermore, a layer of low velocity, low density and high conductivity in the deep crust has been identified as a potential reservoir for mantle-derived natural gas.

The Characteristics of Spinels in Mantle-derivedXenoliths in Cenozoic Basalts from Eastern Chinaand Their Thermal States

: The colours and chemical composition variations of 160 spinels in peridotite and pyroxenite xenoliths from Cenozoic basalts in eastern China and their petrogeneses have been studied in detail. The relationships between major elements of spinels are discussed. The equilibrium temperatures, pressures and oxygen fugacities of spinels and their coexisting olivines, orthopyroxenes and clinopyroxenes have been determined using the Brey—kohler's T—P calculation methods (1990) and Ballhaus' fo2 calculation method (1991). The relationships between the composition and the equilibrium temperatures, pressures or oxygen fugacities of spinels in peridotite xenoliths from the basalts and the stable field of the spinels in the upper mantle have been shown.

GEOCHRONOLOGY AND STRONTIUM,NEODYMIUM ISOTOPE OF MANTLE-DERIVED MAGMATITES FROM THEBU′S GOLD DEPOSIT, NORTHERN XINJIANG,CHINA

Bu’s gold deposit is geographically situated in the northern side of Sawuer Mt., Western Jungar. Magmatites in Bu’s deposit including extrusive and intrusive rocks are widespread and have genetic relationship with the deposit. One volcanic suite and two intrusives are studied here. Extrusive products were formed in the Early Carboniferous with a whole-rock Rb-Sr isochron age of 347 Ma and fossil ages, while intrusions have Rb-Sr isochron ages from 310 to 329 Ma and are intrusive into the Lower Carboniferous and Upper Devonian.The isotope parameters I ranges from 0. 7037 to 0. 7046, from -5. 65^+6.67 and more,goes from +5. 65~ +7. 96, displaying that they have similar material sources and are derived from mantle magmas or their derivatives. The continental crust of Zhaisang diwa region may be initially formed in the Late-Proterozoic or even more earlier and grew probably in terms of non-proportionated model like S. China, N. American and other parts in the world.

氦气资源形成地质条件、成因机理与富集规律

借鉴含油气系统思路及方法,基于典型富氦气田解剖,并利用地球化学成藏方法技术,研究天然气中氦气资源形成的地质条件、成因机理与富集规律。结果表明:①氦气“生-运-聚”机理与天然气有显著差异性,氦气主要为基底富U、Th元素缓慢α衰变或深部壳幔氦释放,沿岩石圈复合输导体系运移至天然气成藏系统,依附适宜载体气聚集成藏。②氦运移输导主要受“岩石圈断裂、基底断裂、沉积层断裂、有效输导层”复合输导体系控制,基于地下流体中“氦-气-水”相平衡及相-势耦合综合分析,提出氦气运聚过程中具有“水溶相、气溶相、游离相”3种主要赋存状态,存在氦气“集流、渗流、扩散”3种运移方式。③富氦气藏形成和氦气富集通常受控于“优质氦源、高效输导、适宜载体”3大主控要素,具有“脱溶汇聚、浮力驱动、压差驱替”3种聚集成藏动力类型,已发现富氦气藏具有相对“近氦源、邻断裂、低势区、高部位”的分布规律和成藏模式。④氦气富集区勘探和评价需要依托天然气兼探/并探,在评价落实氦气“源-运-聚”要素与天然气“生-储-盖”条件耦合匹配性、局部相对低势高部位有利圈闭载体气区的基础上,综合评价优选“通源连圈、低势高位、气氦适配”的有利氦气富集区。

氦气地质理论认识、资源勘查评价与全产业链一体化评价关键技术

鉴于我国氦气产业链理论技术需求,针对国内外尚无系统的氦气地质理论认识,缺乏针对性的氦气资源评价方法、参数取值标准,缺乏氦气含量综合准确检测、有利富集区优选方法,无成本指标优化体系及全产业链一体化评价方法等卡点和难点,本文运用地质、地球化学、重磁电震、投资经济等多学科方法及实验技术,集中力量攻克氦气成藏机理、资源评价及资产评价的关键技术瓶颈。研发形成1项地质理论认识和3项关键技术:基于典型富氦气藏解剖、地下流体中“氦-气-水”相平衡及相-势耦合分析,研究提出氦气“水溶相、气容相、游离相”3种主要赋存状态、“集流、渗流、扩散”3种运移机理、“近氦源、邻断裂、低压区、高部位”4项分布富集控制因素,初步建立了基于“优质氦源、高效输导、适宜载体”的氦气“生-运-聚”地质理论认识。针对国内氦气含量检测技术参差不齐、部分准确度差、与国外数据差别大、无针对性的氦气资源评价方法等系列难题,以氦气源及氦气含量为核心,研发氦气含量综合准确检测技术,构建4类10种氦气资源评价方法,解决了氦气资源分级分类评价的技术瓶颈。针对基底氦源分布、岩性识别、通源断裂刻画及含氦储层评价难题,创建了归一化重磁下延方案,研发了基于深度学习的多尺度断裂智能识别技术和不同氦气含量下的气藏声学性质模拟方法,为氦源岩分布预测、通源断裂刻画、含氦储层测井解释评价及预测奠定了基础。通过建立多元控氦的富氦区带与目标优选技术,解决了富氦区带与目标优选难题。针对国内贫氦实际情况,以提氦装置投资和操作成本最小化为目标,采用响应面法建立优化目标与各主要工艺参数的非线性回归模型,建立了氦气全产业链一体化评价技术,初步解决了天然气低成本提氦工艺流程优化的技术需求。研究成果为我国长期、安全、规模利用氦气资源资产提供了有效支撑。

Fine and hyperfine structures of pionic helium atoms

The fine and hyperfine structures of pionic helium metastable states is calculated within the formalism of the Breit-Pauli Hamiltonian by using the variationally generated wave functions in Hylleraas coordinates.Our results not only verify the existing values of Hori et al.[Phys.Rev.A 89,042515(2014)]for the fine structure of π^(4)He^(+),but also determine the hyperfine structure of π^(3)He^(+).

Rapid growth of nanostructure on tungsten thin film by exposure to helium plasma

A fiberform nanostructure was synthesized by exposing high-density helium plasma to a 100 nm thick tungsten thin film in the linear plasma device NAGDIS-II.After helium plasma exposure,the cross-section of samples was observed by a scanning electron microscope,transmission electron microscope,and focused ion beam scanning electron microscope.It is shown that the thickness of the nanostructured layer increases significantly for only a short irradiation time.The optical absorptivity remains high,even though it is exposed to helium plasma for a short time.The usage of the thin film can shorten the processing time for nanostructure growth,which will be beneficial for commercial production.