The (100) texture of solidified fcc metals, caused by the preferential (100) dendrite growth, could be closeIy related to solid/melt interfaces which behave differently along different crystallographic orientation. Th...The (100) texture of solidified fcc metals, caused by the preferential (100) dendrite growth, could be closeIy related to solid/melt interfaces which behave differently along different crystallographic orientation. The stability and roughness of {111} and {100} solid/melt interfaces of fcc metals were investigated using a modified Temkin multi-layer model. It is demonstrated that {100}crystal/melt interface is more unstable and rougher than {111} interface. The effect of the stability of crystal/melt interface on the (100) texture formation in solidified fcc metals has been analysed and discussed.展开更多
Objective Oil and gas are abundant in the Ordovician Yingshan Formation carbonate karst reservoirs on the northern slope of Tazhong uplift in the Tarim Basin, and have extremely complicated oil-gas-water distribution...Objective Oil and gas are abundant in the Ordovician Yingshan Formation carbonate karst reservoirs on the northern slope of Tazhong uplift in the Tarim Basin, and have extremely complicated oil-gas-water distribution, however. The difference in burial depth of the reservoirs between east and west sides is up to 1000 m. Water-bearing formations exist between oil- and gas-bearing formations vertically and water-producing wells are drilled between oil- and gas-producing wells. Macroscopically, oil and gas occur at low positions, while water occurs at high positiona on the northern slope of Tazhong uplift. The mechanism of differential hydrocarbon enrichment in heterogeneous reservoirs is by far not clarified, which has affected the efficient exploration and development of oil and gas fields in this area.展开更多
1 Introduction Shale formations bear abundant mineral resource and*unconventional petroleum resource,and the unconventional petroleum resource that contain in the shale formation should be integrated and researched.
Homogeneous formation of polychlorinated dibenzothiophenes/thianthrenes（PCDT/TAs）,sulfurated compounds analogous to polychlorinated dibenzo-p-dioxin/dibenzofurans（PCDD/Fs）, has been well-documented to occur via ra...Homogeneous formation of polychlorinated dibenzothiophenes/thianthrenes（PCDT/TAs）,sulfurated compounds analogous to polychlorinated dibenzo-p-dioxin/dibenzofurans（PCDD/Fs）, has been well-documented to occur via radical–radical coupling reactions from chlorinated thiophenol precursors. However, the current understanding of the formation mechanism of PCDT/TAs is exclusively limited to the inherent point of view that chlorothiophenoxy radicals act as the only required intermediates for PCDT/TAs. This study investigates reaction pathways for the formation of PCDT/TAs involving two new types of radical species, i.e., substituted phenyl radicals and substituted thiophenoxyl diradicals. Taking 2-chlorothiophenol（2-CTP） as a model compound for chlorothiophenols,we found that apart from the mostly discussed chlorothiophenoxy radicals, substituted phenyl radicals and substituted thiophenoxyl diradicals could also be readily formed via the reaction of 2-CTP with H radicals. Furthermore, direct self-and cross-coupling of these radicals can result in the formation of PCDT/TAs, including 1-monochlorothianthrene（1-MCTA）, 1,6-dichlorothianthrene（1,6-DCTA）, 4,6-dichlorodibenzothiophene（4,6-DCDT）and 1,6-dichlorodibenzothiophene（1,6-DCDT）. The pathways proposed in this work are proven to be both thermodynamically and kinetically favorable. Particularly, comparisons were made between the formation mechanisms of sulfurated and oxygenated dioxin systems from an energetic point view, showing that replacing oxygen with sulfur atoms greatly reduces the activation barriers of the rate-controlling steps involved in the PCDT/TA formation processes compared with those involved for PCDD/Fs. The calculated results in this work may improve our understanding of the formation mechanism of PCDT/TAs from chlorothiophenol precursors and should be informative to environmental scientists.展开更多
In this letter the study of Li-doped zinc oxide by electron paramagnetic resonance method is described.A signal observed at g_=2.013,g_=1.955 on the degassed sample at 923K was designated to F_s^+ centers(surface oxyg...In this letter the study of Li-doped zinc oxide by electron paramagnetic resonance method is described.A signal observed at g_=2.013,g_=1.955 on the degassed sample at 923K was designated to F_s^+ centers(surface oxygen ion vacancies with a single trapped electron).When the sample was quenched from 1003K into liquid oxygen at 77K under 24 KPa O_2,[Li^+O^-] ion pairs valued at g_=2.026 and g=2.003 with superhyperfine constant a=2.0G,which resulted from ~7Li nucleus,formed at Li^+-substitutional site in ZnO lattice.A probable mechanism of [Li^+O^-]ion pair formation was proposed.展开更多
A transport simulation has been done by using a i.5D time dependent transportcode to reproduce a formation of the ITB on electron temperature Profile during the long pu1seLHCD in JT-60U tokamak. The transport coeffici...A transport simulation has been done by using a i.5D time dependent transportcode to reproduce a formation of the ITB on electron temperature Profile during the long pu1seLHCD in JT-60U tokamak. The transport coefficients were assumed to reduce with a reversedmagnetic shear and the LH driven current profile was evaluated by fitting dynamic change inthe measured current profile. The gradual increase in the central electron temperature could beexplained by the change in the current profile during LHCD in the present simulation model. Theestimated LH-driven current profile by the transport code analysis shows a finite current densityat the plasma center. Analysis of transport simulation suggests some mechanisms for broadeningthe LH-driven current profile at the central region of the plasma.展开更多
The formation and breaking of intramolecular hydrogen bonds of bilirubin in CDCl_3-DMSO-d_6 binary solvent have been investigated by means of NMR spectroscopy.The chemical shifts of protons at dipyrrinone lactam C=O a...The formation and breaking of intramolecular hydrogen bonds of bilirubin in CDCl_3-DMSO-d_6 binary solvent have been investigated by means of NMR spectroscopy.The chemical shifts of protons at dipyrrinone lactam C=O and N-H,Pyrrole N-H,C-5,C-15 and methylene groups of 8,12-propionic acid side-chains changed markedly as a function of composition of the binary solvent.The hydrogen bond formation is dependent on the conformation of propionic acid side-chains.展开更多
In order to establish an animal model with hepatic metastasis intrasplenic inoculation of carcinoma cells from murine uterine cervical carcinoma (U14) was employed. Results showed a high incidence of hepatic metastasi...In order to establish an animal model with hepatic metastasis intrasplenic inoculation of carcinoma cells from murine uterine cervical carcinoma (U14) was employed. Results showed a high incidence of hepatic metastasis could be obtained through the intrasplenic inoculation of 1 × 106 carcinoma cells. Removal of the primary carcinoma through splenec-tomy at different intervals after intrasplenic inoculation proved that the hepatic metastatic mechanism was not due to mechanical pressure but occurred spontaneously. This experimental model provides a useful means for studying the mechanism and prevention of hepatic metastasis.展开更多
The present investigation is concerned with the reaction of barium and iron nitrates mixtures using three different molar ratios, 1:1 (Ⅰ), 1:2 (Ⅱ) and 2:1 (Ⅲ) at different temperatures as pointed out from the DTA d...The present investigation is concerned with the reaction of barium and iron nitrates mixtures using three different molar ratios, 1:1 (Ⅰ), 1:2 (Ⅱ) and 2:1 (Ⅲ) at different temperatures as pointed out from the DTA data. The reaction products exhibit 12 compounds namely, Ba(NO3)2, αFe2O3, Fe3O4, BaFeO3, BaFeO2.9, hexagonal BaFeO3-x, tetragonal BaFeO3-x, BaFe2O4, αBaFe2O4, Ba2Fe6O11, Ba5Fe14O26 and BaFe12O19. The formation of these products depend on the molar ratio between the reactants and the reaction temperature. The reaction products were studied by DTA and TG techniques and characterized by X-ray diffraction patterns, magnetic susceptibility data and scanning electron microscopy, SEM.展开更多
Gamma-cyclodextrin (γ-CD) was used to induce the formation of N,N-diethylaniline (DEA) exciplex in 15:85{φ=0.15)v/v EtOH-H_2O binary mixture.Measurements of the fluorescence spectra of anthracene in the presence or ...Gamma-cyclodextrin (γ-CD) was used to induce the formation of N,N-diethylaniline (DEA) exciplex in 15:85{φ=0.15)v/v EtOH-H_2O binary mixture.Measurements of the fluorescence spectra of anthracene in the presence or absence of DEA and γ-CD show that γ-CD can form 1:1:1 host/vip-Ⅰ/vip-Ⅱ inclusion complex with anthracene and DEA.展开更多
In this work we study all-optical multi-channel return-to-zero （RZ）-on-off keying （OOK） to nonreturn-to-zero （NRZ）-OOK format conversion in single uniform fiber Bragg grating （FBG） for mixed line-rate dense wa...In this work we study all-optical multi-channel return-to-zero （RZ）-on-off keying （OOK） to nonreturn-to-zero （NRZ）-OOK format conversion in single uniform fiber Bragg grating （FBG） for mixed line-rate dense wave- length-division multiplexing systems using mathematical simulations. Forty and 20 Gbit/s RZ-OOK signals with 33% and 50% duty cycles are converted to NRZ-OOK signals in single uniform FBG with 21~ reflectivity. Impact of amplitude noise from FBG contrast profile on modulation format conversion efficiency is also studied.展开更多
One major task of studying the formation and evolution of the Moon is to construct a timeline of the important events with precise isotopic ages.Here,we review recent major isotopic geochronological progress in the pa...One major task of studying the formation and evolution of the Moon is to construct a timeline of the important events with precise isotopic ages.Here,we review recent major isotopic geochronological progress in the past decade and the unsolved problems in isotopic geochronology.The Moon probably formed between 4.52 and 4.42 Ga.Recent high-precision whole-rock and mineral Sm-Nd isotopic dating results suggested that ferroan anorthosite and highlands magnesian suite rocks formed contemporarily around 4.37 to 4.33 Ga.Although the major mare basaltic volcanism took place from 3.85 to 2.93 Ga,new geochronological data from lunar meteorites and Chang’e-5 basalts suggested that lunar basaltic volcanism took place as old as up to 4.37 Ga and at least as young as 2.0 Ga,respectively.Impact events older than 3.9 Ga have also been revealed based on U-bearing minerals Pb/Pb ages and Ar-Ar ages and can provide important clues to understand the late heavy bombardment hypothesis.However,the reliable isotopic ages for the important events on the Moon are still far from conclusive,due to lack of pristine samples that directly crystallized from Lunar Magma Ocean and samples from impact melt sheets in large impact basins(e.g.,the South Pole-Aitken basin).In the future,collection and return of pristine samples of ferroan anorthosite and highlands magnesian suite rocks from the farside,cryptomare basalts and late-stage basalts,quartz monzogabbros,granites/felsites,and rocks from impact melt sheets in large impact basins are required for better understanding the formation and evolution of the Moon.展开更多
文摘The (100) texture of solidified fcc metals, caused by the preferential (100) dendrite growth, could be closeIy related to solid/melt interfaces which behave differently along different crystallographic orientation. The stability and roughness of {111} and {100} solid/melt interfaces of fcc metals were investigated using a modified Temkin multi-layer model. It is demonstrated that {100}crystal/melt interface is more unstable and rougher than {111} interface. The effect of the stability of crystal/melt interface on the (100) texture formation in solidified fcc metals has been analysed and discussed.
基金financially supported by the National Science Foundation of China(grant No.41372146)
文摘Objective Oil and gas are abundant in the Ordovician Yingshan Formation carbonate karst reservoirs on the northern slope of Tazhong uplift in the Tarim Basin, and have extremely complicated oil-gas-water distribution, however. The difference in burial depth of the reservoirs between east and west sides is up to 1000 m. Water-bearing formations exist between oil- and gas-bearing formations vertically and water-producing wells are drilled between oil- and gas-producing wells. Macroscopically, oil and gas occur at low positions, while water occurs at high positiona on the northern slope of Tazhong uplift. The mechanism of differential hydrocarbon enrichment in heterogeneous reservoirs is by far not clarified, which has affected the efficient exploration and development of oil and gas fields in this area.
基金supported by funding the National Basic Research Program of China (973 Program) and the grant number is 2014CB239000
文摘1 Introduction Shale formations bear abundant mineral resource and*unconventional petroleum resource,and the unconventional petroleum resource that contain in the shale formation should be integrated and researched.
基金supported by the National Natural Science Foundation (Nos. 21407167, 21621064, and 21607168)the Chinese Academy of Sciences (No. XDB14030500)
文摘Homogeneous formation of polychlorinated dibenzothiophenes/thianthrenes（PCDT/TAs）,sulfurated compounds analogous to polychlorinated dibenzo-p-dioxin/dibenzofurans（PCDD/Fs）, has been well-documented to occur via radical–radical coupling reactions from chlorinated thiophenol precursors. However, the current understanding of the formation mechanism of PCDT/TAs is exclusively limited to the inherent point of view that chlorothiophenoxy radicals act as the only required intermediates for PCDT/TAs. This study investigates reaction pathways for the formation of PCDT/TAs involving two new types of radical species, i.e., substituted phenyl radicals and substituted thiophenoxyl diradicals. Taking 2-chlorothiophenol（2-CTP） as a model compound for chlorothiophenols,we found that apart from the mostly discussed chlorothiophenoxy radicals, substituted phenyl radicals and substituted thiophenoxyl diradicals could also be readily formed via the reaction of 2-CTP with H radicals. Furthermore, direct self-and cross-coupling of these radicals can result in the formation of PCDT/TAs, including 1-monochlorothianthrene（1-MCTA）, 1,6-dichlorothianthrene（1,6-DCTA）, 4,6-dichlorodibenzothiophene（4,6-DCDT）and 1,6-dichlorodibenzothiophene（1,6-DCDT）. The pathways proposed in this work are proven to be both thermodynamically and kinetically favorable. Particularly, comparisons were made between the formation mechanisms of sulfurated and oxygenated dioxin systems from an energetic point view, showing that replacing oxygen with sulfur atoms greatly reduces the activation barriers of the rate-controlling steps involved in the PCDT/TA formation processes compared with those involved for PCDD/Fs. The calculated results in this work may improve our understanding of the formation mechanism of PCDT/TAs from chlorothiophenol precursors and should be informative to environmental scientists.
基金Supported by Chinese National Scientific Foundation
文摘In this letter the study of Li-doped zinc oxide by electron paramagnetic resonance method is described.A signal observed at g_=2.013,g_=1.955 on the degassed sample at 923K was designated to F_s^+ centers(surface oxygen ion vacancies with a single trapped electron).When the sample was quenched from 1003K into liquid oxygen at 77K under 24 KPa O_2,[Li^+O^-] ion pairs valued at g_=2.026 and g=2.003 with superhyperfine constant a=2.0G,which resulted from ~7Li nucleus,formed at Li^+-substitutional site in ZnO lattice.A probable mechanism of [Li^+O^-]ion pair formation was proposed.
文摘A transport simulation has been done by using a i.5D time dependent transportcode to reproduce a formation of the ITB on electron temperature Profile during the long pu1seLHCD in JT-60U tokamak. The transport coefficients were assumed to reduce with a reversedmagnetic shear and the LH driven current profile was evaluated by fitting dynamic change inthe measured current profile. The gradual increase in the central electron temperature could beexplained by the change in the current profile during LHCD in the present simulation model. Theestimated LH-driven current profile by the transport code analysis shows a finite current densityat the plasma center. Analysis of transport simulation suggests some mechanisms for broadeningthe LH-driven current profile at the central region of the plasma.
文摘The formation and breaking of intramolecular hydrogen bonds of bilirubin in CDCl_3-DMSO-d_6 binary solvent have been investigated by means of NMR spectroscopy.The chemical shifts of protons at dipyrrinone lactam C=O and N-H,Pyrrole N-H,C-5,C-15 and methylene groups of 8,12-propionic acid side-chains changed markedly as a function of composition of the binary solvent.The hydrogen bond formation is dependent on the conformation of propionic acid side-chains.
文摘In order to establish an animal model with hepatic metastasis intrasplenic inoculation of carcinoma cells from murine uterine cervical carcinoma (U14) was employed. Results showed a high incidence of hepatic metastasis could be obtained through the intrasplenic inoculation of 1 × 106 carcinoma cells. Removal of the primary carcinoma through splenec-tomy at different intervals after intrasplenic inoculation proved that the hepatic metastatic mechanism was not due to mechanical pressure but occurred spontaneously. This experimental model provides a useful means for studying the mechanism and prevention of hepatic metastasis.
文摘The present investigation is concerned with the reaction of barium and iron nitrates mixtures using three different molar ratios, 1:1 (Ⅰ), 1:2 (Ⅱ) and 2:1 (Ⅲ) at different temperatures as pointed out from the DTA data. The reaction products exhibit 12 compounds namely, Ba(NO3)2, αFe2O3, Fe3O4, BaFeO3, BaFeO2.9, hexagonal BaFeO3-x, tetragonal BaFeO3-x, BaFe2O4, αBaFe2O4, Ba2Fe6O11, Ba5Fe14O26 and BaFe12O19. The formation of these products depend on the molar ratio between the reactants and the reaction temperature. The reaction products were studied by DTA and TG techniques and characterized by X-ray diffraction patterns, magnetic susceptibility data and scanning electron microscopy, SEM.
文摘Gamma-cyclodextrin (γ-CD) was used to induce the formation of N,N-diethylaniline (DEA) exciplex in 15:85{φ=0.15)v/v EtOH-H_2O binary mixture.Measurements of the fluorescence spectra of anthracene in the presence or absence of DEA and γ-CD show that γ-CD can form 1:1:1 host/vip-Ⅰ/vip-Ⅱ inclusion complex with anthracene and DEA.
基金supported by the European Social Fund within the Project No.2013/0012/1DP/1.1.1.2.0/13/APIA/VIAA/051
文摘In this work we study all-optical multi-channel return-to-zero （RZ）-on-off keying （OOK） to nonreturn-to-zero （NRZ）-OOK format conversion in single uniform fiber Bragg grating （FBG） for mixed line-rate dense wave- length-division multiplexing systems using mathematical simulations. Forty and 20 Gbit/s RZ-OOK signals with 33% and 50% duty cycles are converted to NRZ-OOK signals in single uniform FBG with 21~ reflectivity. Impact of amplitude noise from FBG contrast profile on modulation format conversion efficiency is also studied.
基金supported by the National Natural Science Foundation (42025302 and 41973061)the preresearch Project on Civil Aerospace Technologies funded by CNSA (D020204)+1 种基金the B-type Strategic Priority Program of the Chinese Academy of Sciences (XDB41000000)by the National Natural Science Foundation of China-Academic Divisions of Chinese Academy of Sciences Frontier Interdisciplinary Research Strategic Research Joint Funding Project (L2224032 and XK2022DXC004).
文摘One major task of studying the formation and evolution of the Moon is to construct a timeline of the important events with precise isotopic ages.Here,we review recent major isotopic geochronological progress in the past decade and the unsolved problems in isotopic geochronology.The Moon probably formed between 4.52 and 4.42 Ga.Recent high-precision whole-rock and mineral Sm-Nd isotopic dating results suggested that ferroan anorthosite and highlands magnesian suite rocks formed contemporarily around 4.37 to 4.33 Ga.Although the major mare basaltic volcanism took place from 3.85 to 2.93 Ga,new geochronological data from lunar meteorites and Chang’e-5 basalts suggested that lunar basaltic volcanism took place as old as up to 4.37 Ga and at least as young as 2.0 Ga,respectively.Impact events older than 3.9 Ga have also been revealed based on U-bearing minerals Pb/Pb ages and Ar-Ar ages and can provide important clues to understand the late heavy bombardment hypothesis.However,the reliable isotopic ages for the important events on the Moon are still far from conclusive,due to lack of pristine samples that directly crystallized from Lunar Magma Ocean and samples from impact melt sheets in large impact basins(e.g.,the South Pole-Aitken basin).In the future,collection and return of pristine samples of ferroan anorthosite and highlands magnesian suite rocks from the farside,cryptomare basalts and late-stage basalts,quartz monzogabbros,granites/felsites,and rocks from impact melt sheets in large impact basins are required for better understanding the formation and evolution of the Moon.
