The two-dimensional electron gas(2DEG)formed at the interface between two oxide insulators provides new opportunities for electronics and spintronics.The broken inversion symmetry at the heterointerface results in a R...The two-dimensional electron gas(2DEG)formed at the interface between two oxide insulators provides new opportunities for electronics and spintronics.The broken inversion symmetry at the heterointerface results in a Rashba spin-orbit coupling(RSOC)effect that enables the conversion between spin and charge currents.However,conducting oxide interfaces that simultaneously exhibit strong RSOC and high carrier mobility-a combination query for achieving high spin-to-charge inter-conversion efficiencies-remain scarce.Herein,we report a correlated 2DEG with giant Rashba splitting and high electron mobility in(111)-oriented EuTiO_(3)/KTaO_(3)(ETO/KTO)heterostructures under light illumination.Upon light modulation,a unique carrier-dependent giant anomalous Hall effect,the signature of spin-polarized 2DEG,emerges with a sign crossover at a carrier density of approximately 5.0×10^(13)cm^(-2),highlighting dramatic changes in the band topology of KTO(111)interface.Furthermore,at 2 K,the carrier mobility is enhanced from 103 cm^(2)·V^(-1)·s^(-1)to 1800 cm^(2)·V^(-1)·s^(-1),a remarkable enhancement of approximately 20 times.Accompanying with a giant Rashba coefficient αR up to 360meV·˚A,this high mobility ferromagnetic 5d oxide 2DEG is predicted to achieve a giant spin-to-charge conversion efficiency ofλ~10 nm,showing great potential for designing low-power spin-orbitronic devices.展开更多
With the advantages of long lifetime, high lighting effect and non-pollution, LED lighting has taken a leading role in the lighting sector. LED street and tunnel lights have no unified product interface, so the produc...With the advantages of long lifetime, high lighting effect and non-pollution, LED lighting has taken a leading role in the lighting sector. LED street and tunnel lights have no unified product interface, so the products of different enterprises cannot interchange with each other, restraining the development of the whole industry due to the large-scale production problem. The alliance standard CSA 016-2013 has been approved as a national standard project, paving the way for the orderly development of LED industry. Interpreting the CSA 016 standard, the paper expounds on the technical requirements for interchangeable interface in the optical, mechanical, electrical and thermal aspects.展开更多
Based on vectorial Debye theory, tight focusing of radially and azimuthally polarized vortex beams passing through a dielectric interface are studied. The intensity distribution in the focal region is illustrated by n...Based on vectorial Debye theory, tight focusing of radially and azimuthally polarized vortex beams passing through a dielectric interface are studied. The intensity distribution in the focal region is illustrated by numerical calculations. We show the influence of numerical-aperture （NA） on the full-width at half maximum （FWHM） of the focal spot or the focal hole. It has been found that compared with the azimuthally polarized Besse^Gaussian （BG） beams, the longitudinal component in the z direction of the radially polarized BG beams has no influence on the FWHM of the focal spot and hole, but enhances the total light intensity.展开更多
In China,hot researches on shale oil were raised by the important breakthrough of shale oil in America.Obviously,the first important issue is the actual shale oil resource potential of China,and the selection of the k...In China,hot researches on shale oil were raised by the important breakthrough of shale oil in America.Obviously,the first important issue is the actual shale oil resource potential of China,and the selection of the key appraisement parameter is vital to the shale oil resource amount.Among the appraisement parameters,the oil content parameter(S1)is the key one,but the evaluation result is generally lower because of light hydrocarbon losing and heavy hydrocarbon handling.And the more important thing is that the light hydrocarbon with small molecular weight is more recoverable,and therefore its amount is important to the total shale oil yields.Based on pyrolysis experiments and the kinetic model of hydrocarbon generation,correction factors and a model of light hydrocarbon losing and heavy hydrocarbon handling were established.The results show that the correction factor of heavy hydrocarbon handling is 3.2,and that of light hydrocarbon losing is controlled by kerogen type,maturity and hydrocarbon generation environment(closed or open).展开更多
The effects of rare earths with different contents on anti-degradation of Y base heavy rare earths-magnesium and cerium base light rare earths-magnesium nodular cast iron were studied. Curves of the relationship betwe...The effects of rare earths with different contents on anti-degradation of Y base heavy rare earths-magnesium and cerium base light rare earths-magnesium nodular cast iron were studied. Curves of the relationship between the spheroidization grade of liguid iron treated by different nodulizers and holding time were obtained. The results show that the more the remains of the rare earth, the longer the anti-degradation time, the liquid iron was treated either by Y-Mg-Si or by Ce-Mg-Si nodulizer. When the rare earth remains are above certain quantity, the spheroidization grade starts to decline. When liquid iron treated by either Y-Mg-Si or Ce-Mg-Si nodulizer with proper remains of rare earths about 0.04% 0.06%（mass fraction）, the anti-degradation is the best, and the remains of Mg being about 0.04% -0.07% （mass fraction）. Rare earths-Mg nodulizer with moderate RE remains is better than that of Mg-Si nodulizer in anti-degradation property. However, Y-Mg-Si nodulizer with moderate remins of Re is better than Ce-Mg-Si nodulizer. Sometimes Ce-Mg- Si nodulizer can be used for the production of heavy section nodular cast iron.展开更多
Although numerous studies about the nature and turnover of soil organic matter（SOM） in light and heavy fractions（ LFOM and HFQM, respectively） have been made, little information is available in relation to the rel...Although numerous studies about the nature and turnover of soil organic matter（SOM） in light and heavy fractions（ LFOM and HFQM, respectively） have been made, little information is available in relation to the relationship between LFQM and HFOM, and no attempts have been made to quantify a general relationship between LFQM and HFQM for agricultural soils under field condition. Qur hypothesis is there may be an inherent relationship between LFQM and HFQM for agricultural soils under certain unaltered management practices for a long period, to this end, we therefore studied typically soils taken from different parts in China by using a simple density fractionation procedure. The results indicated that LFQM was positively correlated with LFOM/HFOM ratio for three typical soils. This information will be of particular use not only in deepening our understanding of the dynamics of SQM fractions but also in evaluating the potential of agricultural soils to sequestrate C under different management practices in a long term.展开更多
Different separation techniques such as solvent extraction, ion exchange, and precipitation are often used for recovery of rare earth elements (REEs) from pregnant leach solutions obtained from acid leaching. Solvent ...Different separation techniques such as solvent extraction, ion exchange, and precipitation are often used for recovery of rare earth elements (REEs) from pregnant leach solutions obtained from acid leaching. Solvent extraction is generally accepted as the most appropriate commercial technology for separating REEs due to the need to be able to handle larger volumes of diluted pregnant solutions. This study focused on the development of selective separation of light and heavy REEs from the pregnant leach solution obtained from leaching of apatite ore in 1 M sulfuric acid (H2SO4) using solvent extraction. Three different commercial organophosphorus extractants (di-(2-ethylhexyl) phosphoric acid (D2EHPA), 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC88A) and tributyl phosphate (TBP)), and the influences of experimental parameters such as extractant concentration, organic/aqueous phase ratio, diluent type, pH, extraction time and stripping agent concentration were examined. Results showed that light REEs (LREEs) and heavy REEs (HREEs) in the pregnant leach solution were selectively separated with D2EHPA via a two-stage extraction process. In the first-stage of solvent extraction, >90% of (0.05 g/L) HREEs was extracted with 1.8 M D2EHPA in kerosene while the vast majority (>95%) of LREEs was remained in raffinate. In the second-stage, >93% (1.01 g/L) of LREEs was extracted from the raffinate with 1.8 M D2EHPA dissolved in kerosene at pH 1.6. HREEs (>95%) and LREEs (>90%) loaded with D2EHPA after the first and second-stage of extraction were stripped by 4 M H2SO4 and 1 M H2SO4 solutions, respectively. Distribution of middle rare earth elements (MREEs) was discussed through the extraction processes in this study.展开更多
This paper considers a Manpower system where “exits” of employed personnel produce some wastage or loss. This system monitors these wastages over the sequence of exit epochs {t0 = 0 and tk;k = 1, 2,…} that form a r...This paper considers a Manpower system where “exits” of employed personnel produce some wastage or loss. This system monitors these wastages over the sequence of exit epochs {t0 = 0 and tk;k = 1, 2,…} that form a recurrent process and admit recruitment when the cumulative loss of man hours crosses a threshold level Y, which is also called the breakdown level. It is assumed that the inter-exit times Tk = tk-1 - tk, k = 1, 2,… are independent and identically distributed random variables with a common cumulative distribution function (CDF) B(t) = P(Tk t) which has a tail 1 – B(t) behaving like t-v with 1 v as t → ∞. The amounts {Xk} of wastages incurred during these inter-exit times {Tk} are independent and identically distributed random variables with CDF P(Xk X) = G(x) and Y is distributed, independently of {Xk} and {tk}, as an exponentiated exponential law with CDF H(y) = P(Y y) = (1 - e-λy)n. The mean waiting time to break down of the system has been obtained assuming B(t) to be heavy tailed and as well as light tailed. For the exponential case of G(x), a comparative study has also been made between heavy tailed mean waiting time to break down and light tailed mean waiting time to break down values. The recruitment policy operating under the heavy tailed case is shown to be more economical in all types of manpower systems.展开更多
To study the influence of the speed-up of a freight train with mixed marshaling of light and heavy vehicles on the dynamic behavior,a dynamic model of the freight train was established based on the modular method of c...To study the influence of the speed-up of a freight train with mixed marshaling of light and heavy vehicles on the dynamic behavior,a dynamic model of the freight train was established based on the modular method of cyclic variables,and the dynamic behavior of the freight train was simulated and analyzed under different marshaling patterns,speeds and line conditions.On-site speed-up test with different marshaling freight trains was carried out,and the stability and ride-index of the train before and after the speed-up were compared and analyzed.The feasibility of increasing the speed of freight trains with mixed marshaling of light and heavy cars was demonstrated theoretically and experimentally.The results show that the theory is in good agreement with the test,which can effectively reflect the dynamic behavior of the vehicle.The dynamic behavior of the freight train in the study meets the requirements of increasing speed to 90 km/h.This paper provides a theoretical basis and method for railway freight transportation and the speed-up of freight vehicles.展开更多
The dependence of the directions of polarization of exciton emissions, fine structure splittings （FSS）, and polarization anisotropy on the light- and heavy-hole （LH-HH） mixing in semiconductor quantum dots （QDs）...The dependence of the directions of polarization of exciton emissions, fine structure splittings （FSS）, and polarization anisotropy on the light- and heavy-hole （LH-HH） mixing in semiconductor quantum dots （QDs） is investigated using a mesoscopic model. In general, all QDs have a four-fold exciton ground state. Two exciton states have directions of polarization in the growth-plane, while the other two are along the growth direction of the QD. The LH-HH mixing does affect the FSS and polarization anisotropy of bright exciton states in the growth-plane in the low symmetry QDs （e.g., C2v, CS, C1 ）, while it has no effect on the FSS and polarization anisotropy in high symmetry QDs （e.g., C3V, D2d）. When the hole ground state is pure HH or LH, the bright exciton states in the growth-plane are normal to each other. The LH-HH mixing affects the relative intensities and directions of bright exciton states in the growth-plane of the QD. The polarization anisotropy of exciton emissions in the growth-plane of the QD is independent of the phase angle of LH-HH mixing but strongly depends on the magnitude of LH-HH mixing in low symmetry QDs.展开更多
This study aims to investigate the production of light nuclei,hypertritons,and Ω-hypernuclei in Pb+Pb collisions at √S_(NN)=5.02TeV TeV using a modified analytical nucleon coalescence model with hyperons.To this end...This study aims to investigate the production of light nuclei,hypertritons,and Ω-hypernuclei in Pb+Pb collisions at √S_(NN)=5.02TeV TeV using a modified analytical nucleon coalescence model with hyperons.To this end,the momentum distributions of two bodies coalescing into dibaryon states and of three bodies coalescing into tribaryon states are derived.Available data on coalescence factors B_(2) and B_(3),transverse momentum spectra,averaged transverse momenta,yield rapidity densities,and yield ratios of the deuteron,antihelium-3,antitriton,and hypertriton measured by the ALICE collaboration are explained.Productions of different species of Ω-hypernuclei H(pΩ^(−)),H(nΩ^(−)),and H(pnΩ^(−))are predicted.Particularly,the production correlations of different light(hyper-)nuclei are studied,and two groups of interesting observables-the averaged transverse momentum ratios of light(hyper-)nuclei to protons(hyperons)and their corresponding yield ratios-are studied.The averaged transverse momentum ratio group exhibits a reverse hierarchy of the nucleus size,and the yield raito group is sensitive to the nucleus production mechanism as well as the size of the nucleus.展开更多
The Neogene Shawan Formation in the Chepaizi Uplift of the Junggar Basin(NW China)has obtained high oil flow,demonstrating a good potential for oil and gas exploration.The multi-source hydrocarbon generation backgroun...The Neogene Shawan Formation in the Chepaizi Uplift of the Junggar Basin(NW China)has obtained high oil flow,demonstrating a good potential for oil and gas exploration.The multi-source hydrocarbon generation background and strong tectonic activity have led to the simultaneous production of heavy oil and light oil from multi-layer in the area,which makes it very difficult to identify oil origins,presently,the hot debate on the oil origins needs to be clarified.In this paper,due to the selective consumption of different types of compounds in crude oils by severe and intense biodegradation,the commonly used oilsource correlation tools are ineffective or may produce misleading results,this study adopted a biomarker recovery method based on the principle of mass conservation that uses the sum of the mass of the residual biomarkers and their corresponding biodegradation products to obtain the mass of the original biomarkers,improving the reliability of oil origins determination.Based on the nature and occurrence of crude oils,the investigated oils are subdivided into three types,Group A,Group B and Group C.Group A,light oils occurred mainly in lower structure Neogene Shawan Formation in the western Chepaizi Uplift,while Group B,heavy oils occurred mainly in higher structure Neogene Shawan Formation in the western Chepaizi Uplift.The two types of crude oils may come from the mixed source of Jurassic Badaowan Formation source rocks(J_(1)b)and Paleogene Anjihaihe Formation source rocks(E_(2-3)a)in the Sikeshu Sag,and Jurassic Badaowan Formation source rocks(J_(1)b)are the main source of crude oils.Group C,heavy oils occurred mainly in Neogene Shawan Formation in the eastern Chepaizi Uplift,showing good correlation with the Permian(P_(1)f and P_(2)w)source rocks in the Shawan Sag.At the same time,by combining stable carbon isotope and parameters related to triaromatic steroids,the accuracy of the oilsource correlation results by biomarker recovery method was further verified.展开更多
Soil labile organic carbon （C） plays an important role in improving soil quality. The relatively stable fractions of soil organic C （SOC） represent the bulk of SOC, and are also the primary determinant of the long...Soil labile organic carbon （C） plays an important role in improving soil quality. The relatively stable fractions of soil organic C （SOC） represent the bulk of SOC, and are also the primary determinant of the long-term C balance of terrestrial ecosystems. Different land use types can influence the distribution patterns of different SOC fractions. However, the underlying mechanisms are not well understood. In the present study, different fractions of SOC were determined in two land use types： a grazed grassland （established on previously cultivated cropland 25 years ago, GG） and a long-term cultivated millet cropland （MC）. The results showed that C concentration and C storage of light fractions （LF） and heavy fractions （HF） presented different patterns along the soil profiles in the two sites. More plant residues in GG resulted in 91.9% higher LF storage at the 0-10 cm soil depth, further contributed to 21.9% higher SOC storage at this soil depth; SOC storage at 20-60 cm soil depth in MC was 98.8% higher than that in GG, which could be mainly attributed to the HF storage 104.5% higher than in GG. This might be caused by the long-term application of organic manure, as well as the protection from plough pan and silt- and clay-sized particles. The study indicated that different soil management practices in this region can greatly influence the variations of different SOC fractions, while the conventional tillage can greatly improve the storage of SOC by in- creasing heavy fractions.展开更多
基金supported by the Science Center of the National Science Foundation of China(Grant No.52088101)the National Key Research and Development Program of China(Grant Nos.2023YFA1406400,2021YFA1400300,and 2023YFA1607403)the National Natural Science Foundation of China(Grant Nos.T2394472 and T2394470).
文摘The two-dimensional electron gas(2DEG)formed at the interface between two oxide insulators provides new opportunities for electronics and spintronics.The broken inversion symmetry at the heterointerface results in a Rashba spin-orbit coupling(RSOC)effect that enables the conversion between spin and charge currents.However,conducting oxide interfaces that simultaneously exhibit strong RSOC and high carrier mobility-a combination query for achieving high spin-to-charge inter-conversion efficiencies-remain scarce.Herein,we report a correlated 2DEG with giant Rashba splitting and high electron mobility in(111)-oriented EuTiO_(3)/KTaO_(3)(ETO/KTO)heterostructures under light illumination.Upon light modulation,a unique carrier-dependent giant anomalous Hall effect,the signature of spin-polarized 2DEG,emerges with a sign crossover at a carrier density of approximately 5.0×10^(13)cm^(-2),highlighting dramatic changes in the band topology of KTO(111)interface.Furthermore,at 2 K,the carrier mobility is enhanced from 103 cm^(2)·V^(-1)·s^(-1)to 1800 cm^(2)·V^(-1)·s^(-1),a remarkable enhancement of approximately 20 times.Accompanying with a giant Rashba coefficient αR up to 360meV·˚A,this high mobility ferromagnetic 5d oxide 2DEG is predicted to achieve a giant spin-to-charge conversion efficiency ofλ~10 nm,showing great potential for designing low-power spin-orbitronic devices.
文摘With the advantages of long lifetime, high lighting effect and non-pollution, LED lighting has taken a leading role in the lighting sector. LED street and tunnel lights have no unified product interface, so the products of different enterprises cannot interchange with each other, restraining the development of the whole industry due to the large-scale production problem. The alliance standard CSA 016-2013 has been approved as a national standard project, paving the way for the orderly development of LED industry. Interpreting the CSA 016 standard, the paper expounds on the technical requirements for interchangeable interface in the optical, mechanical, electrical and thermal aspects.
基金Supported by the National Natural Science Foundation of China under Grant No 60477041, the Key Project of Science and Technology of Fujian Province under Grant No 2007H0027, and the Foundation of Science and Technology Development of Southwest Jiaotong University of China under Grant No 2006B01.
文摘Based on vectorial Debye theory, tight focusing of radially and azimuthally polarized vortex beams passing through a dielectric interface are studied. The intensity distribution in the focal region is illustrated by numerical calculations. We show the influence of numerical-aperture （NA） on the full-width at half maximum （FWHM） of the focal spot or the focal hole. It has been found that compared with the azimuthally polarized Besse^Gaussian （BG） beams, the longitudinal component in the z direction of the radially polarized BG beams has no influence on the FWHM of the focal spot and hole, but enhances the total light intensity.
基金supported by"the Fundamental Research Funds for the Central Universities"(14CX05017A)the Natural Science Foundation of China(41330313)+1 种基金Program for New Century Excellent Talents in Heilongjiang Provincial University(1252-NCET-012)CNPC Innovation Foundation(2011D-5006-0101)
文摘In China,hot researches on shale oil were raised by the important breakthrough of shale oil in America.Obviously,the first important issue is the actual shale oil resource potential of China,and the selection of the key appraisement parameter is vital to the shale oil resource amount.Among the appraisement parameters,the oil content parameter(S1)is the key one,but the evaluation result is generally lower because of light hydrocarbon losing and heavy hydrocarbon handling.And the more important thing is that the light hydrocarbon with small molecular weight is more recoverable,and therefore its amount is important to the total shale oil yields.Based on pyrolysis experiments and the kinetic model of hydrocarbon generation,correction factors and a model of light hydrocarbon losing and heavy hydrocarbon handling were established.The results show that the correction factor of heavy hydrocarbon handling is 3.2,and that of light hydrocarbon losing is controlled by kerogen type,maturity and hydrocarbon generation environment(closed or open).
文摘The effects of rare earths with different contents on anti-degradation of Y base heavy rare earths-magnesium and cerium base light rare earths-magnesium nodular cast iron were studied. Curves of the relationship between the spheroidization grade of liguid iron treated by different nodulizers and holding time were obtained. The results show that the more the remains of the rare earth, the longer the anti-degradation time, the liquid iron was treated either by Y-Mg-Si or by Ce-Mg-Si nodulizer. When the rare earth remains are above certain quantity, the spheroidization grade starts to decline. When liquid iron treated by either Y-Mg-Si or Ce-Mg-Si nodulizer with proper remains of rare earths about 0.04% 0.06%（mass fraction）, the anti-degradation is the best, and the remains of Mg being about 0.04% -0.07% （mass fraction）. Rare earths-Mg nodulizer with moderate RE remains is better than that of Mg-Si nodulizer in anti-degradation property. However, Y-Mg-Si nodulizer with moderate remins of Re is better than Ce-Mg-Si nodulizer. Sometimes Ce-Mg- Si nodulizer can be used for the production of heavy section nodular cast iron.
文摘Although numerous studies about the nature and turnover of soil organic matter（SOM） in light and heavy fractions（ LFOM and HFQM, respectively） have been made, little information is available in relation to the relationship between LFQM and HFOM, and no attempts have been made to quantify a general relationship between LFQM and HFQM for agricultural soils under field condition. Qur hypothesis is there may be an inherent relationship between LFQM and HFQM for agricultural soils under certain unaltered management practices for a long period, to this end, we therefore studied typically soils taken from different parts in China by using a simple density fractionation procedure. The results indicated that LFQM was positively correlated with LFOM/HFOM ratio for three typical soils. This information will be of particular use not only in deepening our understanding of the dynamics of SQM fractions but also in evaluating the potential of agricultural soils to sequestrate C under different management practices in a long term.
文摘Different separation techniques such as solvent extraction, ion exchange, and precipitation are often used for recovery of rare earth elements (REEs) from pregnant leach solutions obtained from acid leaching. Solvent extraction is generally accepted as the most appropriate commercial technology for separating REEs due to the need to be able to handle larger volumes of diluted pregnant solutions. This study focused on the development of selective separation of light and heavy REEs from the pregnant leach solution obtained from leaching of apatite ore in 1 M sulfuric acid (H2SO4) using solvent extraction. Three different commercial organophosphorus extractants (di-(2-ethylhexyl) phosphoric acid (D2EHPA), 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC88A) and tributyl phosphate (TBP)), and the influences of experimental parameters such as extractant concentration, organic/aqueous phase ratio, diluent type, pH, extraction time and stripping agent concentration were examined. Results showed that light REEs (LREEs) and heavy REEs (HREEs) in the pregnant leach solution were selectively separated with D2EHPA via a two-stage extraction process. In the first-stage of solvent extraction, >90% of (0.05 g/L) HREEs was extracted with 1.8 M D2EHPA in kerosene while the vast majority (>95%) of LREEs was remained in raffinate. In the second-stage, >93% (1.01 g/L) of LREEs was extracted from the raffinate with 1.8 M D2EHPA dissolved in kerosene at pH 1.6. HREEs (>95%) and LREEs (>90%) loaded with D2EHPA after the first and second-stage of extraction were stripped by 4 M H2SO4 and 1 M H2SO4 solutions, respectively. Distribution of middle rare earth elements (MREEs) was discussed through the extraction processes in this study.
文摘This paper considers a Manpower system where “exits” of employed personnel produce some wastage or loss. This system monitors these wastages over the sequence of exit epochs {t0 = 0 and tk;k = 1, 2,…} that form a recurrent process and admit recruitment when the cumulative loss of man hours crosses a threshold level Y, which is also called the breakdown level. It is assumed that the inter-exit times Tk = tk-1 - tk, k = 1, 2,… are independent and identically distributed random variables with a common cumulative distribution function (CDF) B(t) = P(Tk t) which has a tail 1 – B(t) behaving like t-v with 1 v as t → ∞. The amounts {Xk} of wastages incurred during these inter-exit times {Tk} are independent and identically distributed random variables with CDF P(Xk X) = G(x) and Y is distributed, independently of {Xk} and {tk}, as an exponentiated exponential law with CDF H(y) = P(Y y) = (1 - e-λy)n. The mean waiting time to break down of the system has been obtained assuming B(t) to be heavy tailed and as well as light tailed. For the exponential case of G(x), a comparative study has also been made between heavy tailed mean waiting time to break down and light tailed mean waiting time to break down values. The recruitment policy operating under the heavy tailed case is shown to be more economical in all types of manpower systems.
基金The authors gratefully acknowledge the support of the School-enterprise cooperation projects(No.20200203)。
文摘To study the influence of the speed-up of a freight train with mixed marshaling of light and heavy vehicles on the dynamic behavior,a dynamic model of the freight train was established based on the modular method of cyclic variables,and the dynamic behavior of the freight train was simulated and analyzed under different marshaling patterns,speeds and line conditions.On-site speed-up test with different marshaling freight trains was carried out,and the stability and ride-index of the train before and after the speed-up were compared and analyzed.The feasibility of increasing the speed of freight trains with mixed marshaling of light and heavy cars was demonstrated theoretically and experimentally.The results show that the theory is in good agreement with the test,which can effectively reflect the dynamic behavior of the vehicle.The dynamic behavior of the freight train in the study meets the requirements of increasing speed to 90 km/h.This paper provides a theoretical basis and method for railway freight transportation and the speed-up of freight vehicles.
文摘The dependence of the directions of polarization of exciton emissions, fine structure splittings （FSS）, and polarization anisotropy on the light- and heavy-hole （LH-HH） mixing in semiconductor quantum dots （QDs） is investigated using a mesoscopic model. In general, all QDs have a four-fold exciton ground state. Two exciton states have directions of polarization in the growth-plane, while the other two are along the growth direction of the QD. The LH-HH mixing does affect the FSS and polarization anisotropy of bright exciton states in the growth-plane in the low symmetry QDs （e.g., C2v, CS, C1 ）, while it has no effect on the FSS and polarization anisotropy in high symmetry QDs （e.g., C3V, D2d）. When the hole ground state is pure HH or LH, the bright exciton states in the growth-plane are normal to each other. The LH-HH mixing affects the relative intensities and directions of bright exciton states in the growth-plane of the QD. The polarization anisotropy of exciton emissions in the growth-plane of the QD is independent of the phase angle of LH-HH mixing but strongly depends on the magnitude of LH-HH mixing in low symmetry QDs.
基金supported by the National Natural Science Foundation of China(Nos.12175115 and 12375074).
文摘This study aims to investigate the production of light nuclei,hypertritons,and Ω-hypernuclei in Pb+Pb collisions at √S_(NN)=5.02TeV TeV using a modified analytical nucleon coalescence model with hyperons.To this end,the momentum distributions of two bodies coalescing into dibaryon states and of three bodies coalescing into tribaryon states are derived.Available data on coalescence factors B_(2) and B_(3),transverse momentum spectra,averaged transverse momenta,yield rapidity densities,and yield ratios of the deuteron,antihelium-3,antitriton,and hypertriton measured by the ALICE collaboration are explained.Productions of different species of Ω-hypernuclei H(pΩ^(−)),H(nΩ^(−)),and H(pnΩ^(−))are predicted.Particularly,the production correlations of different light(hyper-)nuclei are studied,and two groups of interesting observables-the averaged transverse momentum ratios of light(hyper-)nuclei to protons(hyperons)and their corresponding yield ratios-are studied.The averaged transverse momentum ratio group exhibits a reverse hierarchy of the nucleus size,and the yield raito group is sensitive to the nucleus production mechanism as well as the size of the nucleus.
基金co-funded by the National Natural Science Foundation of China(42372160,42072172)。
文摘The Neogene Shawan Formation in the Chepaizi Uplift of the Junggar Basin(NW China)has obtained high oil flow,demonstrating a good potential for oil and gas exploration.The multi-source hydrocarbon generation background and strong tectonic activity have led to the simultaneous production of heavy oil and light oil from multi-layer in the area,which makes it very difficult to identify oil origins,presently,the hot debate on the oil origins needs to be clarified.In this paper,due to the selective consumption of different types of compounds in crude oils by severe and intense biodegradation,the commonly used oilsource correlation tools are ineffective or may produce misleading results,this study adopted a biomarker recovery method based on the principle of mass conservation that uses the sum of the mass of the residual biomarkers and their corresponding biodegradation products to obtain the mass of the original biomarkers,improving the reliability of oil origins determination.Based on the nature and occurrence of crude oils,the investigated oils are subdivided into three types,Group A,Group B and Group C.Group A,light oils occurred mainly in lower structure Neogene Shawan Formation in the western Chepaizi Uplift,while Group B,heavy oils occurred mainly in higher structure Neogene Shawan Formation in the western Chepaizi Uplift.The two types of crude oils may come from the mixed source of Jurassic Badaowan Formation source rocks(J_(1)b)and Paleogene Anjihaihe Formation source rocks(E_(2-3)a)in the Sikeshu Sag,and Jurassic Badaowan Formation source rocks(J_(1)b)are the main source of crude oils.Group C,heavy oils occurred mainly in Neogene Shawan Formation in the eastern Chepaizi Uplift,showing good correlation with the Permian(P_(1)f and P_(2)w)source rocks in the Shawan Sag.At the same time,by combining stable carbon isotope and parameters related to triaromatic steroids,the accuracy of the oilsource correlation results by biomarker recovery method was further verified.
基金supported by National Basic Research Program of China (2014CB138703)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA05050403)+3 种基金Changjiang Scholars and Innovative Research Team in University (IRT13019)Key Science and Technology Projects of Gansu Province (1203FKDA035)Fundamental Research Funds for the Central Universities (lzujbky-2014-78)the National Natural Science Foundation of China (31070412, 31201837)
文摘Soil labile organic carbon （C） plays an important role in improving soil quality. The relatively stable fractions of soil organic C （SOC） represent the bulk of SOC, and are also the primary determinant of the long-term C balance of terrestrial ecosystems. Different land use types can influence the distribution patterns of different SOC fractions. However, the underlying mechanisms are not well understood. In the present study, different fractions of SOC were determined in two land use types： a grazed grassland （established on previously cultivated cropland 25 years ago, GG） and a long-term cultivated millet cropland （MC）. The results showed that C concentration and C storage of light fractions （LF） and heavy fractions （HF） presented different patterns along the soil profiles in the two sites. More plant residues in GG resulted in 91.9% higher LF storage at the 0-10 cm soil depth, further contributed to 21.9% higher SOC storage at this soil depth; SOC storage at 20-60 cm soil depth in MC was 98.8% higher than that in GG, which could be mainly attributed to the HF storage 104.5% higher than in GG. This might be caused by the long-term application of organic manure, as well as the protection from plough pan and silt- and clay-sized particles. The study indicated that different soil management practices in this region can greatly influence the variations of different SOC fractions, while the conventional tillage can greatly improve the storage of SOC by in- creasing heavy fractions.
