Cocatalyst plays key roles in photogenerated charge separation and surface catalytic reactions in photocatalysis.However,it is not clear if the chemical states of cocatalysts changed or remains unchanged under photoca...Cocatalyst plays key roles in photogenerated charge separation and surface catalytic reactions in photocatalysis.However,it is not clear if the chemical states of cocatalysts changed or remains unchanged under photocatalytic reaction conditions.Herein,taking NaTaO3 as an example,we systemically investigated the chemical states of nickel‐based cocatalysts during photocatalytic water splitting reaction.It was found that photo‐induced self‐formation of Ni and NiO cocatalyst species take place on the surface of NaTaO3 nanocrystals.The self‐formation of dual‐cocatalysts not only occurs on 26‐facet NaTaO3,but also takes place on a more general 6‐facet NaTaO3.Our work clarified that the chemical states of cocatalysts are changing and the redox dual‐cocatalysts are redistributed on the semiconductor surface owing to the reaction induced by photogenerated charges under the condition of photocatalytic reactions.展开更多
It is important to predict the fracture distribution in the tight reservoirs of the Ordos Basin because fracturing is very crucial for the reconstruction of the low-permeability reservoirs. Three-dimensional finite el...It is important to predict the fracture distribution in the tight reservoirs of the Ordos Basin because fracturing is very crucial for the reconstruction of the low-permeability reservoirs. Three-dimensional finite element models are used to predict the fracture orientation and distribution of the Triassic Yanchang Formation in the Longdong area, southern Ordos Basin. The numerical modeling is based on the distribution of sand bodies in the Chang 7a and 72 members, and the different forces that have been exerted along each boundary of the basin in the Late Mesozoic and the Cenozoic. The calculated results demonstrate that the fracture orientations in the Late Mesozoic and the Ceno- zoic are NW-EW and NNE-ENE, respectively. In this paper, the two-factor method is applied to analyze the distribution of fracture density. The distribution maps of predicted fracture density in the Chang 71 and 72 members are obtained, indicating that the tectonic movement in the Late Mesozoic has a greater influence on the fracture development than that in the Cenozoic. The average fracture densities in the Chang 71 and 72 members are similar, but there are differences in their distributions. Compared with other geological elements, the lithology and the layer thickness are the primary factors that control the stress distribution in the study area, which further determine the fracture distribution in the stable Ordos Basin. The predicted fracture density and the two-factor method can be utilized to guide future exploration in the tight-sand reservoirs.展开更多
Background:miRNAs are closely related to bone metabolism.Studies have shown that Erxian decoction can improve bone metabolism,possibly achieving this regulatory effect through miRNA targets.Netinfer was used to predic...Background:miRNAs are closely related to bone metabolism.Studies have shown that Erxian decoction can improve bone metabolism,possibly achieving this regulatory effect through miRNA targets.Netinfer was used to predict the miRNA targets of Erxian decoction for the treatment of postmenopausal osteoporosis,and the results were validated by clinical trials.Methods:In this study,we identified possible targets of Erxian decoction in osteoporosis by means of network pharmacological analysis and bioinformatic prediction.Fifteen cases of postmenopausal osteoporosis with kidney Yin and Yang deficiency(In traditional Chinese medicine,kidney Yin nourishes and moistens the tissues of the internal organs of the body,while kidney Yang promotes and warms the tissues of the internal organs of the body.)were treated with Erxian decoction for four weeks,and serum bone metabolism indices(P1NP,osteocalcin,andβ-CTX)and miRNA-335-5p expression were measured before and after treatment.Results:The constructed miRNA postmenopausal osteoporosis related gene network of the effective compound of the Erxian decoction has 296 points and 981 edges.The 39 postmenopausal osteoporosis related genes regulated by miRNA-335-5p were enriched in ossification,while the signaling pathways were enriched in rheumatoid arthritis,the Toll signaling pathway,the HIF-1 signaling pathway,and the MAPK signaling pathway.After taking Erxian decoction,the expression of the serum bone formation index(P1NP,osteocalcin)and miRNA-335-5p gene expression levels increased significantly.The alterations in P1NP and osteocalcin were correlated with the changes in miRNA-335-5p.Conclusion:Circulating miRNA-335-5p may serve as an important target of Erxian decoction in the treatment of postmenopausal women.The effect of Erxian decoction on bone formation is significant,but the underlying mechanism requires further investigation.展开更多
Sandstones attributed to different lacustrine sediment gravity flows are present in the 7th and 6th members of the Yanchang Formation in the Ordos Basin, China. These differences in their origins led to different sand...Sandstones attributed to different lacustrine sediment gravity flows are present in the 7th and 6th members of the Yanchang Formation in the Ordos Basin, China. These differences in their origins led to different sandstone distributions which control the scale and connectivity of oil and gas reservoirs. Numerous cores and outcrops were analysed to understand the origins of these sandstones. The main origin of these sandstones was analysed by statistical methods, and well logging data were used to study their vertical and horizontal distributions. Results show that the sandstones in the study area accu- mulated via sandy debris flows, turbidity currents and slumping, and sandy debris flows predominate. The sand- stone associated with a single event is characteristically small in scale and exhibits poor lateral continuity. How- ever, as a result of multiple events that stacked gravity flow-related sandstones atop one another, sandstones are extensive overall, as illustrated in the cross section and isopach maps. Finally, a depositional model was developed in which sandy debris flows predominated and various other types of small-scale gravity flows occurred frequently, resulting in extensive deposition of sand bodies across a large area.展开更多
Water breakdown studies by Nd-YAG laser pulses of duration 100 fs, 30 ps and 6 ns at wavelength 1064 nm are pre- formed to investigate the physical mechanisms which couple the laser energy into the medium. Calculation...Water breakdown studies by Nd-YAG laser pulses of duration 100 fs, 30 ps and 6 ns at wavelength 1064 nm are pre- formed to investigate the physical mechanisms which couple the laser energy into the medium. Calculations are carried out applying a modified kinetic model of water breakdown previously developed by Kennedy (1995) to investigate the correlation between threshold intensity of breakdown and laser pulse length. The modifications considered the introduction of diffusion and recombination loss processes which might take place under the experimental conditions applied in these calculations. The validity of the model is tested by comparing the calculated threshold intensities and the experimentally measured ones where good agreement is shown. The study of the time evolution of the electron density clarifies the correlation between the pulse length and dominant ionization mechanism. The analysis of the spatial distribution of the electron density along the radial and axial distances of the focal spot showed that the size of the formed plasma increases with the increase of the pulse length. On the other hand, studies of self-focusing effect illustrated that under the investigated experimental conditions the effect of this process has an effective contribution only at laser pulses of the order of femtosecond scale when the laser beam is focused by a lens of a focal length ≥8.0 cm. This result in turns assures that using femtosecond pulses in ophthalmic microsurgery could be a safe tool from the retinal damage.展开更多
Mechanical stimuli play an essential role in maintaining bone remodeling and skeletal integrity.Meanwhile,bone can respond to the changes of mechanical condition to adjust its mass and architecture.Clinical studies di...Mechanical stimuli play an essential role in maintaining bone remodeling and skeletal integrity.Meanwhile,bone can respond to the changes of mechanical condition to adjust its mass and architecture.Clinical studies discover that bedridden patients showed osteoporotic T-scores and low bone mineral density,and long-term immobilized patients presented reduced markers of bone formation.However,as bone formation mediated by osteoblast differentiation is a complex process,the underlying molecular mechanism of mechanical stimuli regulating bone formation is still unclear.Recent evidences show that microRNAs(miRNAs)are involved in mechanical stimuli regulating bone formation or osteoblast differentiation.Nevertheless,no direct evidence identifies mechanoresponsive miRNA in both human and animal bones,and clarifies its mechanoresponsive role under different mechanical conditions(e.g.mechanical unloading,reloading,loading).In the current study,we screened for differentially expressed miRNAs in bone specimens of bedridden patients with fractures,then identified that the expression of miR-138-5p,but not the other miRNAs,altered withbedridden time and was negatively correlated with the expression of the bone formation marker genes Alp(alkaline phosphatase).Moreover,miR-138-5p was up-regulated with reduced bone formation during unloading and down-regulated with increased bone formation during reloading in hind4imb unloaded mice.In addition,miR-138-5p was verified to be responsive to different mechanical unloading condition and cyclic mechanical stretch condition in primary osteogenic cells,respectively.Further in vitro data suggested that mechanoresponsive miR-138-5p directly targeted microtubule actin crosslinking factor 1(MACF1)to inhibit osteoblast differentiation.In vivo,we constructed an osteoblastic miR-138-5p transgenic mice model(TG138)with the Runx2promoter,and found that overexpression miR-138-5p supressed bone formation.Moreover,osteoblast-targeted inhibition of miR-138-5p sensitized bone anabolic response to mechanical loading in TG138 mice.Predominantly,the osteoblast-targeted inhibition of miR-138-5p could counteract bone formation reduction induced by hind limb unloading.Taken together,the mechanoresponsive miR-138-5p inhibited bone anabolic response for developing a novel bone anabolic sensitization strategy.展开更多
This paper considers nonlinear dynamics of teth- ered three-body formation system with their centre of mass staying on a circular orbit around the Earth, and applies the theory of space manifold dynamics to deal with ...This paper considers nonlinear dynamics of teth- ered three-body formation system with their centre of mass staying on a circular orbit around the Earth, and applies the theory of space manifold dynamics to deal with the nonlinear dynamical behaviors of the equilibrium configurations of the system. Compared with the classical circular restricted three body system, sixteen equilibrium configurations are obtained globally from the geometry of pseudo-potential energy sur- face, four of which were omitted in the previous research. The periodic Lyapunov orbits and their invariant manifolds near the hyperbolic equilibria are presented, and an iteration procedure for identifying Lyapunov orbit is proposed based on the differential correction algorithm. The non-transversal intersections between invariant manifolds are addressed to generate homoclinic and heteroclinic trajectories between the Lyapunov orbits. (3,3)- and (2,1)-heteroclinic trajecto- ries from the neighborhood of one collinear equilibrium to that of another one, and (3,6)- and (2,1)-homoclinic trajecto- ries from and to the neighborhood of the same equilibrium, are obtained based on the Poincar6 mapping technique.展开更多
The observation of oxygen(O)-and nitrogen(N)-bearing molecules gives an idea about the complex prebiotic chemistry in the interstellar medium.Recent millimeter and submillimeter wavelength observations have shown the ...The observation of oxygen(O)-and nitrogen(N)-bearing molecules gives an idea about the complex prebiotic chemistry in the interstellar medium.Recent millimeter and submillimeter wavelength observations have shown the presence of complex O-and N-bearing molecules in the star formation regions.So,the investigation of those molecules is crucial to understanding the chemical complexity in the star-forming regions.In this article,we present the identification of the rotational emission lines of N-bearing molecules ethyl cyanide(C_(2)H_(5)CN)and cyanoacetylene(HC_(3)N),and O-bearing molecule methyl formate(CH_(3)OCHO)toward high-mass protostar IRAS18089–1732 using the Atacama Compact Array.We also detected the emission lines of both the N-and O-bearing molecule formamide(NH_(2)CHO)in the envelope of IRAS 18089–1732.We have detected the v=0 and 1 state rotational emission lines of CH_(3)OCHO.We also detected the two vibrationally excited states of HC_(3)N(v7=1 and v7=2).The estimated fractional abundances of C_(2)H_(5)CN,HC_(3)N(v7=1),HC_(3)N(v7=2),and NH_(2)CHO toward IRAS 18089–1732 are(1.40±0.5)×10^(-10),(7.5±0.7)×10^(-11),(3.1±0.4)×10^(-11),and(6.25±0.82)×10^(-11)respectively.Similarly,the estimated fractional abundances of CH_(3)OCHO(v=0)and CH_(3)OCHO(v=1)are(1.90±0.9)×10^(-9)and(8.90±0.8)×10^(-10),respectively.We also created the integrated emission maps of the detected molecules,and the observed molecules may have originated from the extended envelope of the protostar.We show that C_(2)H_(5)CNand HC_(3)N are most probably formed via the subsequential hydrogenation of the CH_(2)CHCNand the reaction between C_(2)H_(2)and CN on the grain surface of IRAS 18089–1732.We found that NH_(2)CHO is probably produced due to the reaction between NH_(2)and H_(2)CO in the gas phase.Similarly,CH_(3)OCHO is possibly created via the reaction between radical CH_(3)O and radical HCO on the grain surface of IRAS 18089–1732.展开更多
This paper reports that low-temperature heat capacities of 4-(2-aminoethyl)-phenol (C8H11NO) are measured by a precision automated adiabatic calorimeter over the temperature range from 78 to 400 K. A polynomial eq...This paper reports that low-temperature heat capacities of 4-(2-aminoethyl)-phenol (C8H11NO) are measured by a precision automated adiabatic calorimeter over the temperature range from 78 to 400 K. A polynomial equation of heat capacities as a function of the temperature was fitted by the least square method. Based on the fitted polynomial, the smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15K were calculated and tabulated at the interval of 5K. The energy equivalent, εcalor, of the oxygen-bomb combustion calorimeter has been determined from 0.68g of NIST 39i benzoic acid to be εcalor=(14674.69±17.49)J·K^-1. The constant-volume energy of combustion of the compound at T=298.15 K was measured by a precision oxygen-bomb combustion calorimeter to be ΔcU=-(32374.25±12.93)J·g^-1. The standard molar enthalpy of combustion for the compound was calculated to be ΔcHm = -(4445.47 ± 1.77) kJ·mol^-1 according to the definition of enthalpy of combustion and other thermodynamic principles. Finally, the standard molar enthalpy of formation of the compound was derived to be ΔfHm(C8H11NO, s)=-(274.68 ±2.06) kJ·mol^-1, in accordance with Hess law.展开更多
In a semi-numerical model of reionization, the evolution of ionization fraction is approximately simulated by the criterion of ionizing photon to baryon ratio. We incorporate a semi-analytical model of galaxy formatio...In a semi-numerical model of reionization, the evolution of ionization fraction is approximately simulated by the criterion of ionizing photon to baryon ratio. We incorporate a semi-analytical model of galaxy formation based on the Millennium II N-body simulation into the semi-numerical modeling of reionization. The semianalytical model is used to predict the production of ionizing photons, then we use the semi-numerical method to model the reionization process. Such an approach allows more detailed modeling of the reionization, and also connects observations of galaxies at low and high redshifts to the reionization history. The galaxy formation model we use was designed to match the low-z observations, and it also fits the high redshift luminosity function reasonably well, but its prediction about star formation falls below the observed value, and we find that it also underpredicts the stellar ionizing photon production rate, hence the reionization cannot be completed at z ~ 6. We also consider simple modifications of the model with more top heavy initial mass functions, which can allow the reionization to occur at earlier epochs. The incorporation of the semi-analytical model may also affect the topology of the HI regions during the epoch of reionization, and the neutral regions produced by our simulations with the semi-analytical model, which appeared less poriferous than the simple halo-based models.展开更多
A simple technique for preparing cauliflower-like PMMA particles by a self-formation method is proposed. PMMA particles can be obtained with tunable surface morphology by varying the polymerization time. Experimental ...A simple technique for preparing cauliflower-like PMMA particles by a self-formation method is proposed. PMMA particles can be obtained with tunable surface morphology by varying the polymerization time. Experimental results show that the formation of these cauliflower-like particles can be attributed to the special particle growth mechanism in the self-formation method.展开更多
A new non-simplified model of formation flying is derived in the presence of an oblate main- body and third-body perturbation. In the proposed model, considering the perturbation of the third- body in an inclined orbi...A new non-simplified model of formation flying is derived in the presence of an oblate main- body and third-body perturbation. In the proposed model, considering the perturbation of the third- body in an inclined orbit, the effect of obliquity (axial tilt) of the main-body is becoming important and has been propounded in the absolute motion of a reference satellite and the relative motion of a follower satellite. From a new point of view, J2 perturbed relative motion equations and considering a disturbing body in an elliptic inclined three dimensional orbit, are derived using Lagrangian mechanics based on accurate introduced perturbed reference satellite motion. To validate the accuracy of the model presented in this study, an auxiliary model was constructed as the Main-body Center based Relative Motion (MCRM) model. Finally, the importance of the main-body's obliquity is demonstrated by several examples related to the Earth-Moon system in relative motion and lunar satellite formation keeping. The main-body's obliquity has a remarkable effect on formation keeping in the examined in-track and projected circular orbit (PCO) formations.展开更多
We have performed a multi-wavelength study toward a quasi-sinusoidal filament(CFG028.68–0.28). A new large-scale ^12CO J = 3-2 map was obtained from the China-Cologne Observation for Sub Millimeter Astronomy(CCOSMA) ...We have performed a multi-wavelength study toward a quasi-sinusoidal filament(CFG028.68–0.28). A new large-scale ^12CO J = 3-2 map was obtained from the China-Cologne Observation for Sub Millimeter Astronomy(CCOSMA) 3m radio telescope. Based on the ATLASGAL catalog, we have identified 27 dust clumps in the filament. Through the relationship between the mass and radius of these clumps, 67% of these clumps are dense and massive enough to potentially form massive stars. The obtained CFE is ~11% in the filament. The filament has a linear mass density of ~305 M⊙pc^-1, which is smaller than its critical mass to length ratio. This suggests that the external pressure from the neighboring H Ⅱ regions may help prevent the filament from dispersing under the effects of turbulence. Comparing the energy injection from outflows and H Ⅱ regions in the filament, the ionization feedback from the H Ⅱ regions can help maintain the observed turbulence.展开更多
The bicyclic cryptand 1,4,7, 10,13,16,21, 24-octaaza-bigcyclo [8, 8,8] hexacosan-3, 8, 12, 17, 20, 25-hex-one (COBH) bearing diaminoethane groups along the eight-atom bridges was synthesized. The structure consists of...The bicyclic cryptand 1,4,7, 10,13,16,21, 24-octaaza-bigcyclo [8, 8,8] hexacosan-3, 8, 12, 17, 20, 25-hex-one (COBH) bearing diaminoethane groups along the eight-atom bridges was synthesized. The structure consists of discrete neutral macrobicyclic units; the two cycles share the two tertiary amine nitrogen atoms, which exhibit an endo-cndo conformation. Three identical branches formed by 1, 2-diaminoethane link the two tertiary amine groups. The protonation reactions of cryptand (COBH) and its complex formation with copper (II) were investigated by potentiometry in water and in a DMSO/water (80:20 in mass ratio) mixture as solvents. The cryptand acts as a his-base through its two N-bridgehead and exhibits a strong cooperativity that favors the first protonation and makes the second one difficult (△pK= 5.0). An inward rotation of the amide groups to form hydrogen bonds accounts for this cooperativity. The interaction of COBH with copper (II) leads to several binuclear complex proton contents.展开更多
How Escherichia coli bacteria develop a particular colonial, 3-D biofilm morphological pattern is still a poorly understood process. Recently, we reported a new E. coli K-12 morphotype exhibited by old macrocolonies d...How Escherichia coli bacteria develop a particular colonial, 3-D biofilm morphological pattern is still a poorly understood process. Recently, we reported a new E. coli K-12 morphotype exhibited by old macrocolonies described as volcano-like. The formative developmental process of this morphotype has been presented as a suitable experimental model for the study of 3D patterning in macrocolony biofilms. Here, we report the optical microscopy observations and genetic analysis that have unveiled the existence of a novel autoaggregative behaviour which generates massive lumpiness over the surface of the volcano-like macrocolonies. These lumpy formations are generated by the autoaggregation and strong interaction of tightly packed bacterial cells in structures with a chondrule-like appearance which give the colony’s surface its characteristic microscopic lumpy phenotype. Furthermore, they exhibit different levels of maturation from the edge to the center of the colony. Hence, its generation appears to follow a spatiotemporal program of development during the macrocolony’s morphogenesis. Interestingly, the agar’s hardness influences the morphology exhibited by these formations, with high agar concentration (1.5%, 15 g/L) suppressing its development. This new auto-aggregative E. coli’s behaviour does not require the activity of the biofilm master regulator CsgD, the adhesiveness of flagella, pili type 1, adhesin Ag43, β-1,6-N-acetyl-D-glucosamine polymer-PGA, cellulose or colanic acid, but it is under glucose repression and the control of cAMP receptor protein (CRP). The possible physiological role of these chondrule-like formations in the adaptability of the colony to different stressful environmental conditions is discussed.展开更多
Based on the theory of stability of the liquid metal under the action of surface tension,a physical mod- el is established for the mechanisms of the bead formation deferct' humping', which is generated durin...Based on the theory of stability of the liquid metal under the action of surface tension,a physical mod- el is established for the mechanisms of the bead formation deferct' humping', which is generated during high - speed welding.A boundary function is introduced to correct the model,theoretical results got by the model correspond well with the experimental phenomena. A two - dimensional conducting model is adoopted in the simulation of the temperature field during high - speed welding.Finally, the factors acting upon the stability of liquid metal are analyzed.展开更多
In the south of the Ordos Basin, the oil source of the Upper Triassic Yanchang Formation is confused all the time, which affects further exploration. In this study, oil sources from the oil layers of Ch6, Ch8 and Ch9 ...In the south of the Ordos Basin, the oil source of the Upper Triassic Yanchang Formation is confused all the time, which affects further exploration. In this study, oil sources from the oil layers of Ch6, Ch8 and Ch9 are all analyzed and confirmed. Through their carbon isotope value and biomarkers, characteristics of crude oils from the Yanchang Formation are analyzed. Then, the oil–source relation is discussed, with the source rocks' features.Finally, the oil–source relation is calculated through cluster analysis. It is believed that the oils from the Yanchang Formation deposit in a similar redox environment, with weak oxidation–weak reduction, and have all entered maturity stage. Ch9 crude oil is more mature than crude oils from Ch6 and Ch8, and has more advanced plants and fewer algae. Gas chromatography(GC) and gas chromatography–mass spectrometry(GC–MS) analysis show that crude oils from Ch6 and Ch8 may come from Ch7, and Ch9 crude oil may not. Cluster analysis displays that crude oils from Ch6 and Ch8 have closer squared Euclidean distance with Ch7 source rocks than Ch9 crude oil does,indicating crude oils from Ch6 and Ch8 stem from Ch7 source rocks. And Ch9 crude oil has rather close squared Euclidean distance with Ch9 source rocks, illustrating Ch9 crude oil may be from Ch9 source rocks. This research may provide the theoretical basis for the next exploration deploy in the south of Ordos Basin.展开更多
A number of condensate reservoirs with high concentrations of H2S have been discovered in the deep dolomite reservoirs of the lower Ordovician Yingshan Formation(O1y) in the Tazhong Uplift, where the formation water...A number of condensate reservoirs with high concentrations of H2S have been discovered in the deep dolomite reservoirs of the lower Ordovician Yingshan Formation(O1y) in the Tazhong Uplift, where the formation water has a high p H value. In the O1y reservoir, the concentrations of Mg^2+ and SO4^2-in the formation water are higher than those in the upper Ordovician formation.The concentration of H2 S in the condensate reservoirs and the concentration of Mg^2+in the formation water correlate well in the O1y reservoirs of the Tazhong Uplift, which indicates a presumed thermochemical sulfate reduction(TSR) origin of H2S according to the oxidation theory of contact ion-pairs(CIPs). Besides, the p H values of the formation water are positively correlated with the concentration of H2S in the condensate reservoirs, which may indicate that high p H might be another factor to promote and maintain TSR. Oil–source correlation of biomarkers in the sulfuretted condensates indicates the Cambrian source rocks could be the origin of condensates. The formation water in the condensate reservoirs of O1y is similar to that in the Cambrian; therefore, the TSR of sulfate-CIPs likelyoccurred in the Cambrian. High H2S-bearing condensates are mainly located near the No. 1 Fault and NE-SW strikeslip faults, which are the major migration pathway of deep fluids in the Tazhong Uplift. The redox between sulfateCIPs and hydrocarbons is the generation mechanism of H2S in the deep dolomite condensate reservoirs of the Tazhong Uplift. This finding should be helpful to predict the fluid properties of deep dolomite reservoirs.展开更多
Based on a physical treatment of the star formation law similar to that given by Efstathiou, we have improved our two-component chemical evolution model for the Milky Way disk. Two gas infall rates are compared, one e...Based on a physical treatment of the star formation law similar to that given by Efstathiou, we have improved our two-component chemical evolution model for the Milky Way disk. Two gas infall rates are compared, one exponential, one Gaussian. It is shown that the star formation law adopted in this paper depends more strongly on the gas surface density than that in Chang et al. It has large effects on the history of star formation and gas evolution of the whole disk. In the solar neighborhood, the history of chemical evolution and star formation is not sensitive to whether the infall rate is Gaussian or exponential. For the same infall time scale, both forms predict the same behavior for the current properties of the Galactic disk. The model predictions do depend on whether or not the infall time scale varies with the radius, but current available observations cannot decide which case is the more realistic. Our results also show that it would be inadequate to describe the gradient evolution along the Galactic disk by only one word "flatter" or "steeper", as was suggested by Hou et al. and Chiapinni et al. We point out that both the absolute value and the evolution of the abundance gradient may be different in the inner and outer regions.展开更多
After sea level rises during the Early Cretaceous, upper parts of the Khami Group sediments (Fahliyan, Gadvan, and Dariyan Formations) deposited over Jurassic sediments. The Lower Cretaceous (Aptian) Dariyan Forma...After sea level rises during the Early Cretaceous, upper parts of the Khami Group sediments (Fahliyan, Gadvan, and Dariyan Formations) deposited over Jurassic sediments. The Lower Cretaceous (Aptian) Dariyan Formation (equivalent to the Shu'aiba Formation and Hawar Member of the Arabian Plate) carbonates, which have hydrocarbon reservoir potential, form the uppermost portion of the Khami Group that unconformably overlays the Gadvan Formation and was unconformably covered by the Kazhdumi Formation and Burgan sandstones. Detailed paleontological, sedimentological, and well log analysis were performed on seven wells from Qeshm Island and offshore in order to analyze the sequence stratigraphy of this interval and correlate with other studies of the Dariyan Formation in this region. According to this study, the Dariyan Formation contains 14 carbonate lithofacies, which deposited on a ramp system that deepened in both directions (NE-wells 5, 6 and SWIwells 1, 2). Sequence stratigraphy led to recognition of 5 Aptian third-order sequences toward the Bab Basin (SW-well 1) and 4 Aptian third-order sequences toward Qeshm Island (NE-wells 5 and 6) so these areas show higher gamma on the gamma ray logs and probably have higher source rock potential. Other wells (wells 2-4 and 7) mainly deposited in shallower ramp systems and contain 3 Aptian third-order sequences. On the other hand, rudstone and boundstone lithofacies of studied wells have higher reservoir potential and were deposited during Apt 3 and Apt 4 sequences of the Arabian Plate. The Dariyan Formation in Qeshm Island (well 6) and adjacent well (well 5) was deposited in an intrashelf basin that should be classified as a new intrashelf basin in future Aptian paleogeographic maps. We interpret that salt-related differential subsidence, crustal warping, and reactivation of basement faults of the Arabian Plate boundary were responsible for the creation of the intrashelf basin in the Qeshm area.展开更多
文摘Cocatalyst plays key roles in photogenerated charge separation and surface catalytic reactions in photocatalysis.However,it is not clear if the chemical states of cocatalysts changed or remains unchanged under photocatalytic reaction conditions.Herein,taking NaTaO3 as an example,we systemically investigated the chemical states of nickel‐based cocatalysts during photocatalytic water splitting reaction.It was found that photo‐induced self‐formation of Ni and NiO cocatalyst species take place on the surface of NaTaO3 nanocrystals.The self‐formation of dual‐cocatalysts not only occurs on 26‐facet NaTaO3,but also takes place on a more general 6‐facet NaTaO3.Our work clarified that the chemical states of cocatalysts are changing and the redox dual‐cocatalysts are redistributed on the semiconductor surface owing to the reaction induced by photogenerated charges under the condition of photocatalytic reactions.
基金funded by the National Natural Science Foundations of China(Grant Nos.40772121 and 41530207)State Key Projects of Petroleum(Nos.2008ZX05029001,2011ZX05029-001 and 2014A0213)Research and Development Foundations of the Huaneng Clean Energy Research Institute(TY-15-CERI02)
文摘It is important to predict the fracture distribution in the tight reservoirs of the Ordos Basin because fracturing is very crucial for the reconstruction of the low-permeability reservoirs. Three-dimensional finite element models are used to predict the fracture orientation and distribution of the Triassic Yanchang Formation in the Longdong area, southern Ordos Basin. The numerical modeling is based on the distribution of sand bodies in the Chang 7a and 72 members, and the different forces that have been exerted along each boundary of the basin in the Late Mesozoic and the Cenozoic. The calculated results demonstrate that the fracture orientations in the Late Mesozoic and the Ceno- zoic are NW-EW and NNE-ENE, respectively. In this paper, the two-factor method is applied to analyze the distribution of fracture density. The distribution maps of predicted fracture density in the Chang 71 and 72 members are obtained, indicating that the tectonic movement in the Late Mesozoic has a greater influence on the fracture development than that in the Cenozoic. The average fracture densities in the Chang 71 and 72 members are similar, but there are differences in their distributions. Compared with other geological elements, the lithology and the layer thickness are the primary factors that control the stress distribution in the study area, which further determine the fracture distribution in the stable Ordos Basin. The predicted fracture density and the two-factor method can be utilized to guide future exploration in the tight-sand reservoirs.
基金supported by Suzhou Special Project for Diagnosis and Treatment Technology of Clinical Key Diseases(No.LCZX202127)。
文摘Background:miRNAs are closely related to bone metabolism.Studies have shown that Erxian decoction can improve bone metabolism,possibly achieving this regulatory effect through miRNA targets.Netinfer was used to predict the miRNA targets of Erxian decoction for the treatment of postmenopausal osteoporosis,and the results were validated by clinical trials.Methods:In this study,we identified possible targets of Erxian decoction in osteoporosis by means of network pharmacological analysis and bioinformatic prediction.Fifteen cases of postmenopausal osteoporosis with kidney Yin and Yang deficiency(In traditional Chinese medicine,kidney Yin nourishes and moistens the tissues of the internal organs of the body,while kidney Yang promotes and warms the tissues of the internal organs of the body.)were treated with Erxian decoction for four weeks,and serum bone metabolism indices(P1NP,osteocalcin,andβ-CTX)and miRNA-335-5p expression were measured before and after treatment.Results:The constructed miRNA postmenopausal osteoporosis related gene network of the effective compound of the Erxian decoction has 296 points and 981 edges.The 39 postmenopausal osteoporosis related genes regulated by miRNA-335-5p were enriched in ossification,while the signaling pathways were enriched in rheumatoid arthritis,the Toll signaling pathway,the HIF-1 signaling pathway,and the MAPK signaling pathway.After taking Erxian decoction,the expression of the serum bone formation index(P1NP,osteocalcin)and miRNA-335-5p gene expression levels increased significantly.The alterations in P1NP and osteocalcin were correlated with the changes in miRNA-335-5p.Conclusion:Circulating miRNA-335-5p may serve as an important target of Erxian decoction in the treatment of postmenopausal women.The effect of Erxian decoction on bone formation is significant,but the underlying mechanism requires further investigation.
基金supported by the Science Foundation Programs(41302115)
文摘Sandstones attributed to different lacustrine sediment gravity flows are present in the 7th and 6th members of the Yanchang Formation in the Ordos Basin, China. These differences in their origins led to different sandstone distributions which control the scale and connectivity of oil and gas reservoirs. Numerous cores and outcrops were analysed to understand the origins of these sandstones. The main origin of these sandstones was analysed by statistical methods, and well logging data were used to study their vertical and horizontal distributions. Results show that the sandstones in the study area accu- mulated via sandy debris flows, turbidity currents and slumping, and sandy debris flows predominate. The sand- stone associated with a single event is characteristically small in scale and exhibits poor lateral continuity. How- ever, as a result of multiple events that stacked gravity flow-related sandstones atop one another, sandstones are extensive overall, as illustrated in the cross section and isopach maps. Finally, a depositional model was developed in which sandy debris flows predominated and various other types of small-scale gravity flows occurred frequently, resulting in extensive deposition of sand bodies across a large area.
文摘Water breakdown studies by Nd-YAG laser pulses of duration 100 fs, 30 ps and 6 ns at wavelength 1064 nm are pre- formed to investigate the physical mechanisms which couple the laser energy into the medium. Calculations are carried out applying a modified kinetic model of water breakdown previously developed by Kennedy (1995) to investigate the correlation between threshold intensity of breakdown and laser pulse length. The modifications considered the introduction of diffusion and recombination loss processes which might take place under the experimental conditions applied in these calculations. The validity of the model is tested by comparing the calculated threshold intensities and the experimentally measured ones where good agreement is shown. The study of the time evolution of the electron density clarifies the correlation between the pulse length and dominant ionization mechanism. The analysis of the spatial distribution of the electron density along the radial and axial distances of the focal spot showed that the size of the formed plasma increases with the increase of the pulse length. On the other hand, studies of self-focusing effect illustrated that under the investigated experimental conditions the effect of this process has an effective contribution only at laser pulses of the order of femtosecond scale when the laser beam is focused by a lens of a focal length ≥8.0 cm. This result in turns assures that using femtosecond pulses in ophthalmic microsurgery could be a safe tool from the retinal damage.
基金supported by the National Natural Science Foundation of China ( 31570940,81772017)
文摘Mechanical stimuli play an essential role in maintaining bone remodeling and skeletal integrity.Meanwhile,bone can respond to the changes of mechanical condition to adjust its mass and architecture.Clinical studies discover that bedridden patients showed osteoporotic T-scores and low bone mineral density,and long-term immobilized patients presented reduced markers of bone formation.However,as bone formation mediated by osteoblast differentiation is a complex process,the underlying molecular mechanism of mechanical stimuli regulating bone formation is still unclear.Recent evidences show that microRNAs(miRNAs)are involved in mechanical stimuli regulating bone formation or osteoblast differentiation.Nevertheless,no direct evidence identifies mechanoresponsive miRNA in both human and animal bones,and clarifies its mechanoresponsive role under different mechanical conditions(e.g.mechanical unloading,reloading,loading).In the current study,we screened for differentially expressed miRNAs in bone specimens of bedridden patients with fractures,then identified that the expression of miR-138-5p,but not the other miRNAs,altered withbedridden time and was negatively correlated with the expression of the bone formation marker genes Alp(alkaline phosphatase).Moreover,miR-138-5p was up-regulated with reduced bone formation during unloading and down-regulated with increased bone formation during reloading in hind4imb unloaded mice.In addition,miR-138-5p was verified to be responsive to different mechanical unloading condition and cyclic mechanical stretch condition in primary osteogenic cells,respectively.Further in vitro data suggested that mechanoresponsive miR-138-5p directly targeted microtubule actin crosslinking factor 1(MACF1)to inhibit osteoblast differentiation.In vivo,we constructed an osteoblastic miR-138-5p transgenic mice model(TG138)with the Runx2promoter,and found that overexpression miR-138-5p supressed bone formation.Moreover,osteoblast-targeted inhibition of miR-138-5p sensitized bone anabolic response to mechanical loading in TG138 mice.Predominantly,the osteoblast-targeted inhibition of miR-138-5p could counteract bone formation reduction induced by hind limb unloading.Taken together,the mechanoresponsive miR-138-5p inhibited bone anabolic response for developing a novel bone anabolic sensitization strategy.
基金supported by the National Natural Science Foundation of China(11172020)Talent Foundation supported by the Fundamental Research Funds for the Central Universities+1 种基金Aerospace Science and Technology Innovation Foundation of China Aerospace Science Corporationthe National High Technology Research and Development Program of China(863)(2012AA120601)
文摘This paper considers nonlinear dynamics of teth- ered three-body formation system with their centre of mass staying on a circular orbit around the Earth, and applies the theory of space manifold dynamics to deal with the nonlinear dynamical behaviors of the equilibrium configurations of the system. Compared with the classical circular restricted three body system, sixteen equilibrium configurations are obtained globally from the geometry of pseudo-potential energy sur- face, four of which were omitted in the previous research. The periodic Lyapunov orbits and their invariant manifolds near the hyperbolic equilibria are presented, and an iteration procedure for identifying Lyapunov orbit is proposed based on the differential correction algorithm. The non-transversal intersections between invariant manifolds are addressed to generate homoclinic and heteroclinic trajectories between the Lyapunov orbits. (3,3)- and (2,1)-heteroclinic trajecto- ries from the neighborhood of one collinear equilibrium to that of another one, and (3,6)- and (2,1)-homoclinic trajecto- ries from and to the neighborhood of the same equilibrium, are obtained based on the Poincar6 mapping technique.
基金the Swami Vivekananda Merit-cum-Means Scholarship(SVMCM)for financial support for this research。
文摘The observation of oxygen(O)-and nitrogen(N)-bearing molecules gives an idea about the complex prebiotic chemistry in the interstellar medium.Recent millimeter and submillimeter wavelength observations have shown the presence of complex O-and N-bearing molecules in the star formation regions.So,the investigation of those molecules is crucial to understanding the chemical complexity in the star-forming regions.In this article,we present the identification of the rotational emission lines of N-bearing molecules ethyl cyanide(C_(2)H_(5)CN)and cyanoacetylene(HC_(3)N),and O-bearing molecule methyl formate(CH_(3)OCHO)toward high-mass protostar IRAS18089–1732 using the Atacama Compact Array.We also detected the emission lines of both the N-and O-bearing molecule formamide(NH_(2)CHO)in the envelope of IRAS 18089–1732.We have detected the v=0 and 1 state rotational emission lines of CH_(3)OCHO.We also detected the two vibrationally excited states of HC_(3)N(v7=1 and v7=2).The estimated fractional abundances of C_(2)H_(5)CN,HC_(3)N(v7=1),HC_(3)N(v7=2),and NH_(2)CHO toward IRAS 18089–1732 are(1.40±0.5)×10^(-10),(7.5±0.7)×10^(-11),(3.1±0.4)×10^(-11),and(6.25±0.82)×10^(-11)respectively.Similarly,the estimated fractional abundances of CH_(3)OCHO(v=0)and CH_(3)OCHO(v=1)are(1.90±0.9)×10^(-9)and(8.90±0.8)×10^(-10),respectively.We also created the integrated emission maps of the detected molecules,and the observed molecules may have originated from the extended envelope of the protostar.We show that C_(2)H_(5)CNand HC_(3)N are most probably formed via the subsequential hydrogenation of the CH_(2)CHCNand the reaction between C_(2)H_(2)and CN on the grain surface of IRAS 18089–1732.We found that NH_(2)CHO is probably produced due to the reaction between NH_(2)and H_(2)CO in the gas phase.Similarly,CH_(3)OCHO is possibly created via the reaction between radical CH_(3)O and radical HCO on the grain surface of IRAS 18089–1732.
基金supported by the National Natural Science Foundation of China (Grant No 20673050)
文摘This paper reports that low-temperature heat capacities of 4-(2-aminoethyl)-phenol (C8H11NO) are measured by a precision automated adiabatic calorimeter over the temperature range from 78 to 400 K. A polynomial equation of heat capacities as a function of the temperature was fitted by the least square method. Based on the fitted polynomial, the smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15K were calculated and tabulated at the interval of 5K. The energy equivalent, εcalor, of the oxygen-bomb combustion calorimeter has been determined from 0.68g of NIST 39i benzoic acid to be εcalor=(14674.69±17.49)J·K^-1. The constant-volume energy of combustion of the compound at T=298.15 K was measured by a precision oxygen-bomb combustion calorimeter to be ΔcU=-(32374.25±12.93)J·g^-1. The standard molar enthalpy of combustion for the compound was calculated to be ΔcHm = -(4445.47 ± 1.77) kJ·mol^-1 according to the definition of enthalpy of combustion and other thermodynamic principles. Finally, the standard molar enthalpy of formation of the compound was derived to be ΔfHm(C8H11NO, s)=-(274.68 ±2.06) kJ·mol^-1, in accordance with Hess law.
基金supported by the MOST 863 Project (No. 2012AA121701)the National Natural Science Foundation of China (Grant No. 11073024)+1 种基金CAS grant KJCX2-EW-W01the John Templeton Foundation
文摘In a semi-numerical model of reionization, the evolution of ionization fraction is approximately simulated by the criterion of ionizing photon to baryon ratio. We incorporate a semi-analytical model of galaxy formation based on the Millennium II N-body simulation into the semi-numerical modeling of reionization. The semianalytical model is used to predict the production of ionizing photons, then we use the semi-numerical method to model the reionization process. Such an approach allows more detailed modeling of the reionization, and also connects observations of galaxies at low and high redshifts to the reionization history. The galaxy formation model we use was designed to match the low-z observations, and it also fits the high redshift luminosity function reasonably well, but its prediction about star formation falls below the observed value, and we find that it also underpredicts the stellar ionizing photon production rate, hence the reionization cannot be completed at z ~ 6. We also consider simple modifications of the model with more top heavy initial mass functions, which can allow the reionization to occur at earlier epochs. The incorporation of the semi-analytical model may also affect the topology of the HI regions during the epoch of reionization, and the neutral regions produced by our simulations with the semi-analytical model, which appeared less poriferous than the simple halo-based models.
基金This project was supported by the National Nature Science Foundation of China (Nos. 20204018 and 20374058).
文摘A simple technique for preparing cauliflower-like PMMA particles by a self-formation method is proposed. PMMA particles can be obtained with tunable surface morphology by varying the polymerization time. Experimental results show that the formation of these cauliflower-like particles can be attributed to the special particle growth mechanism in the self-formation method.
文摘A new non-simplified model of formation flying is derived in the presence of an oblate main- body and third-body perturbation. In the proposed model, considering the perturbation of the third- body in an inclined orbit, the effect of obliquity (axial tilt) of the main-body is becoming important and has been propounded in the absolute motion of a reference satellite and the relative motion of a follower satellite. From a new point of view, J2 perturbed relative motion equations and considering a disturbing body in an elliptic inclined three dimensional orbit, are derived using Lagrangian mechanics based on accurate introduced perturbed reference satellite motion. To validate the accuracy of the model presented in this study, an auxiliary model was constructed as the Main-body Center based Relative Motion (MCRM) model. Finally, the importance of the main-body's obliquity is demonstrated by several examples related to the Earth-Moon system in relative motion and lunar satellite formation keeping. The main-body's obliquity has a remarkable effect on formation keeping in the examined in-track and projected circular orbit (PCO) formations.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11363004, 11433008, 11633007, 11703040, 11743007, 11773014,11847309 and 11851305)the Youth Innovation Promotion Association of CAS+1 种基金the National Key R&D Programs of China (Nos. 2017YFA0402600 and 2015CB857100)supported by the Open Project Program of the Key Laboratory of FAST, NAOC, Chinese Academy of Sciences
文摘We have performed a multi-wavelength study toward a quasi-sinusoidal filament(CFG028.68–0.28). A new large-scale ^12CO J = 3-2 map was obtained from the China-Cologne Observation for Sub Millimeter Astronomy(CCOSMA) 3m radio telescope. Based on the ATLASGAL catalog, we have identified 27 dust clumps in the filament. Through the relationship between the mass and radius of these clumps, 67% of these clumps are dense and massive enough to potentially form massive stars. The obtained CFE is ~11% in the filament. The filament has a linear mass density of ~305 M⊙pc^-1, which is smaller than its critical mass to length ratio. This suggests that the external pressure from the neighboring H Ⅱ regions may help prevent the filament from dispersing under the effects of turbulence. Comparing the energy injection from outflows and H Ⅱ regions in the filament, the ionization feedback from the H Ⅱ regions can help maintain the observed turbulence.
基金the National Natural Science Foundation of China (No.29875018) and the Natural Science Foundation of Gansu Province (ZS991-A25-
文摘The bicyclic cryptand 1,4,7, 10,13,16,21, 24-octaaza-bigcyclo [8, 8,8] hexacosan-3, 8, 12, 17, 20, 25-hex-one (COBH) bearing diaminoethane groups along the eight-atom bridges was synthesized. The structure consists of discrete neutral macrobicyclic units; the two cycles share the two tertiary amine nitrogen atoms, which exhibit an endo-cndo conformation. Three identical branches formed by 1, 2-diaminoethane link the two tertiary amine groups. The protonation reactions of cryptand (COBH) and its complex formation with copper (II) were investigated by potentiometry in water and in a DMSO/water (80:20 in mass ratio) mixture as solvents. The cryptand acts as a his-base through its two N-bridgehead and exhibits a strong cooperativity that favors the first protonation and makes the second one difficult (△pK= 5.0). An inward rotation of the amide groups to form hydrogen bonds accounts for this cooperativity. The interaction of COBH with copper (II) leads to several binuclear complex proton contents.
文摘How Escherichia coli bacteria develop a particular colonial, 3-D biofilm morphological pattern is still a poorly understood process. Recently, we reported a new E. coli K-12 morphotype exhibited by old macrocolonies described as volcano-like. The formative developmental process of this morphotype has been presented as a suitable experimental model for the study of 3D patterning in macrocolony biofilms. Here, we report the optical microscopy observations and genetic analysis that have unveiled the existence of a novel autoaggregative behaviour which generates massive lumpiness over the surface of the volcano-like macrocolonies. These lumpy formations are generated by the autoaggregation and strong interaction of tightly packed bacterial cells in structures with a chondrule-like appearance which give the colony’s surface its characteristic microscopic lumpy phenotype. Furthermore, they exhibit different levels of maturation from the edge to the center of the colony. Hence, its generation appears to follow a spatiotemporal program of development during the macrocolony’s morphogenesis. Interestingly, the agar’s hardness influences the morphology exhibited by these formations, with high agar concentration (1.5%, 15 g/L) suppressing its development. This new auto-aggregative E. coli’s behaviour does not require the activity of the biofilm master regulator CsgD, the adhesiveness of flagella, pili type 1, adhesin Ag43, β-1,6-N-acetyl-D-glucosamine polymer-PGA, cellulose or colanic acid, but it is under glucose repression and the control of cAMP receptor protein (CRP). The possible physiological role of these chondrule-like formations in the adaptability of the colony to different stressful environmental conditions is discussed.
文摘Based on the theory of stability of the liquid metal under the action of surface tension,a physical mod- el is established for the mechanisms of the bead formation deferct' humping', which is generated during high - speed welding.A boundary function is introduced to correct the model,theoretical results got by the model correspond well with the experimental phenomena. A two - dimensional conducting model is adoopted in the simulation of the temperature field during high - speed welding.Finally, the factors acting upon the stability of liquid metal are analyzed.
基金supported with funding from the National Natural Science Foundation of China(No.41173055)
文摘In the south of the Ordos Basin, the oil source of the Upper Triassic Yanchang Formation is confused all the time, which affects further exploration. In this study, oil sources from the oil layers of Ch6, Ch8 and Ch9 are all analyzed and confirmed. Through their carbon isotope value and biomarkers, characteristics of crude oils from the Yanchang Formation are analyzed. Then, the oil–source relation is discussed, with the source rocks' features.Finally, the oil–source relation is calculated through cluster analysis. It is believed that the oils from the Yanchang Formation deposit in a similar redox environment, with weak oxidation–weak reduction, and have all entered maturity stage. Ch9 crude oil is more mature than crude oils from Ch6 and Ch8, and has more advanced plants and fewer algae. Gas chromatography(GC) and gas chromatography–mass spectrometry(GC–MS) analysis show that crude oils from Ch6 and Ch8 may come from Ch7, and Ch9 crude oil may not. Cluster analysis displays that crude oils from Ch6 and Ch8 have closer squared Euclidean distance with Ch7 source rocks than Ch9 crude oil does,indicating crude oils from Ch6 and Ch8 stem from Ch7 source rocks. And Ch9 crude oil has rather close squared Euclidean distance with Ch9 source rocks, illustrating Ch9 crude oil may be from Ch9 source rocks. This research may provide the theoretical basis for the next exploration deploy in the south of Ordos Basin.
基金funded by the Natural Science Foundation of China (NSFC, Project No. 41473020)the CNPC International Cooperation Project (Grant No. 2011A-0203-01)
文摘A number of condensate reservoirs with high concentrations of H2S have been discovered in the deep dolomite reservoirs of the lower Ordovician Yingshan Formation(O1y) in the Tazhong Uplift, where the formation water has a high p H value. In the O1y reservoir, the concentrations of Mg^2+ and SO4^2-in the formation water are higher than those in the upper Ordovician formation.The concentration of H2 S in the condensate reservoirs and the concentration of Mg^2+in the formation water correlate well in the O1y reservoirs of the Tazhong Uplift, which indicates a presumed thermochemical sulfate reduction(TSR) origin of H2S according to the oxidation theory of contact ion-pairs(CIPs). Besides, the p H values of the formation water are positively correlated with the concentration of H2S in the condensate reservoirs, which may indicate that high p H might be another factor to promote and maintain TSR. Oil–source correlation of biomarkers in the sulfuretted condensates indicates the Cambrian source rocks could be the origin of condensates. The formation water in the condensate reservoirs of O1y is similar to that in the Cambrian; therefore, the TSR of sulfate-CIPs likelyoccurred in the Cambrian. High H2S-bearing condensates are mainly located near the No. 1 Fault and NE-SW strikeslip faults, which are the major migration pathway of deep fluids in the Tazhong Uplift. The redox between sulfateCIPs and hydrocarbons is the generation mechanism of H2S in the deep dolomite condensate reservoirs of the Tazhong Uplift. This finding should be helpful to predict the fluid properties of deep dolomite reservoirs.
文摘Based on a physical treatment of the star formation law similar to that given by Efstathiou, we have improved our two-component chemical evolution model for the Milky Way disk. Two gas infall rates are compared, one exponential, one Gaussian. It is shown that the star formation law adopted in this paper depends more strongly on the gas surface density than that in Chang et al. It has large effects on the history of star formation and gas evolution of the whole disk. In the solar neighborhood, the history of chemical evolution and star formation is not sensitive to whether the infall rate is Gaussian or exponential. For the same infall time scale, both forms predict the same behavior for the current properties of the Galactic disk. The model predictions do depend on whether or not the infall time scale varies with the radius, but current available observations cannot decide which case is the more realistic. Our results also show that it would be inadequate to describe the gradient evolution along the Galactic disk by only one word "flatter" or "steeper", as was suggested by Hou et al. and Chiapinni et al. We point out that both the absolute value and the evolution of the abundance gradient may be different in the inner and outer regions.
基金the National Iranian Oil Company,Exploration Directorate,for the support of this researchthe Department of Geology at Ferdowsi University of Mashhad for their support
文摘After sea level rises during the Early Cretaceous, upper parts of the Khami Group sediments (Fahliyan, Gadvan, and Dariyan Formations) deposited over Jurassic sediments. The Lower Cretaceous (Aptian) Dariyan Formation (equivalent to the Shu'aiba Formation and Hawar Member of the Arabian Plate) carbonates, which have hydrocarbon reservoir potential, form the uppermost portion of the Khami Group that unconformably overlays the Gadvan Formation and was unconformably covered by the Kazhdumi Formation and Burgan sandstones. Detailed paleontological, sedimentological, and well log analysis were performed on seven wells from Qeshm Island and offshore in order to analyze the sequence stratigraphy of this interval and correlate with other studies of the Dariyan Formation in this region. According to this study, the Dariyan Formation contains 14 carbonate lithofacies, which deposited on a ramp system that deepened in both directions (NE-wells 5, 6 and SWIwells 1, 2). Sequence stratigraphy led to recognition of 5 Aptian third-order sequences toward the Bab Basin (SW-well 1) and 4 Aptian third-order sequences toward Qeshm Island (NE-wells 5 and 6) so these areas show higher gamma on the gamma ray logs and probably have higher source rock potential. Other wells (wells 2-4 and 7) mainly deposited in shallower ramp systems and contain 3 Aptian third-order sequences. On the other hand, rudstone and boundstone lithofacies of studied wells have higher reservoir potential and were deposited during Apt 3 and Apt 4 sequences of the Arabian Plate. The Dariyan Formation in Qeshm Island (well 6) and adjacent well (well 5) was deposited in an intrashelf basin that should be classified as a new intrashelf basin in future Aptian paleogeographic maps. We interpret that salt-related differential subsidence, crustal warping, and reactivation of basement faults of the Arabian Plate boundary were responsible for the creation of the intrashelf basin in the Qeshm area.