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Hydrocarbon migration mechanism in deep Ordovician reservoir of the Halahatang area, Tarim Basin, is investigated based on the analysis of the geological setting and geochemical parameters. The parameters successfully analyzed include oil–gas properties, crude oil maturity [Ts/(Ts + Tm) ratio], gas carbon isotopic ratios, and trace elements (B, V, Ni, and Cu) in crude oil. The results show that hydrocarbons migrate into the Ordovician of the Halahatang area from the Manjiaer Depression and the Halahatang area itself through unconformities and faults. The overall hydrocarbon migration orientation in the area is generally from south to north. The oil and gas migration process determine parameters vary regularly from south to north as follows: oil density, V/Ni ratio, Ni/Cu ratio, and concentrations of V, Ni and (Ni + B) in crude oil regularly increase, whereas Ts/(Ts + Tm), gas/oil ratio, and dryness coefficient gradually decrease, and methane show a trend toward depletion of heavy carbon isotopes. Additionally, there exist obvious anomalies of geochemical parameter values in the Repu3 well block, which indicates that a local fault intersection could provide a favorable hydrocarbon filling point. Based on these findings, further exploration activities in the deep Ordovician reservoir of the Halahatang area should be conducted in the southern part of the Halahatang area along the oil charging pathways, and fault intersection zones should be emphasized.

The Early Cambrian is a key interval in the global development of biological evolution, in which occurred many important environmental events and organic-rich sedimentary layers were deposited, which formed important hydrocarbon source rocks. The Lower Cambrian Niutitang Formation is one of the most important marine sedimentary layers in the Yangtze region, South China, and it records abundant important geological information that can be used for the reconstruction of the Lower Cambrian paleo-climates and paleo-environments. Nitrogen isotope compositions record and reflect variations in the original sedimentary environment and the redox conditions of marine ecosystems. Trace elements are also reliable indicators of sedimentary environments. In this study, we collected samples from the Lower Cambrian Niutitang Formation shale in the upper-middle Yangtze region of South China and measured the nitrogen isotope values of bulk sediments (δ15Nbulk), as well as their organic carbon isotope values (δ13Corg), total organic carbon (TOC) contents, total nitrogen (TN) contents and trace element concentrations. The δ15Nbulk values of the Niutitang shale range from 0.6‰ to 2.8‰, they show a certain positive excursion from bottom to top in the longitudinal direction, and they exhibit a significant correlation with the longitudinal variations in trace elements. These trace element characteristics suggest that the lower section of the Niutitang Formation existed in a strongly reduced sedimentary environment and was located in a hydrothermally active layer. During the deposition of the lower section of black shale, the nitrogen cycle was dominated by anaerobic nitrogen fixation; thus, its nitrogen isotope values are relatively lighter. In contrast, during the deposition of the upper section of the Niutitang Formation, the redox conditions of water column were unstable, the oxygen contents increased, and oxygenated reactions were intermittent or localized; thus producing relatively strong isotopic fractionation and causing the δ15Nbulk values in the upper section of black shale to exhibit a positive excursion. We conclude that the sedimentary environment is the key factor affecting nitrogen isotopes and that the redox conditions of the water column exhibit a significant correlation with the nitrogen isotope values.

Natural gases in the Carboniferous Donghe Sandstone reservoir within the Block HD4 of the Hadexun Oilfield, Tarim Basin are characterized by abnormally low total hydrocarbon gas contents ( δ13C ethane (C2)

Deep sour gases are found in the Ordovician carbonate reservoir of the Tazhong Uplift in the Tarim Basin, northwest China. All sour gases in this field are dominated by gas hydrocarbons (C1–C4) with varying amounts of H2S. Most of the gases in the eastern Tazhong are characterized by high gas dryness coefficients (>0.95), 13C-enriched methane (δ13C1 ranging from −44.6‰ to −35.8‰), and small difference between values of the δ13C2 and δ13C1 (δ13C2-1). In contrast, the gases in the western Tazhong are characterized by relatively low gas dryness coefficients (mostly

The Ordovician hydrocarbon migration and accumulation of the Tazhong Uplift in the Tarim Basin, northwest China, is investigated from the perspective of geological and geochemical analysis. Geochem...

The economical synthesis of amphiphilic Janus nanosheets in large amounts for practical applications is a grand challenge. This work reports a facile and scalable method to prepare graphene-based amphiphilic Janus nanosheets with much higher efficiency than the previously-reported wax template masking method. Graphene oxide (GO) was immobilized by hydrogen bonding on the surfaces of starch microspheres, confirmed by both experiments and Molecular Dynamics simulations. After selective functionalization of the exposed surface with alkylamine, amphiphilic Janus nanosheets (AJN) were obtained by releasing the nanosheets from the starch microspheres via breaking the hydrogen bonding. The interfacial behavior of AJN shows its amphiphilicity and the asymmetrical surface wettability indicated from the difference of contact angles, further demonstrated its Janus nature. In addition, avoiding of dissolving the template materials in comparison with wax masking method was also benefit for environment and recycling.

Research on noble gases is important which can provide more information on gas origins and sources due to their special chemical inertness and genesis related to nuclear processes. However, few studies have been carried out on noble gases in the largest un-compartmentalized gas field in the Tarim Basin. In this study, molecular and isotopic compositions of noble gases and hydrocarbon gases in the Kela 2 gas field were analyzed. Hydrocarbon gases are the dominant gases, accompanied by minor N 2 , CO 2 and extremely low contents of noble gases in the Kela 2 gas field. He content is generally 1 order of magnitude higher comparing to that of air, while Ne, Ar, Kr, and Xe contents are 1–3 orders of magnitude lower than corresponding atmospheric values. The δ 13 C 2 value indicates natural gases in the Kela 2 gas field are typical coal-derived gases. Noble gases in the Kela 2 gas field are typical crustal derived source, mainly originating from decay of crustal radioactive elements. Natural gases in the Kela 2 gas field are speculated to be derived from the coal measures source rocks of Triassic to Jurassic with major contribution from coals and secondary contribution from mudstones.

The lower third and upper fourth members of the Eocene Shahejie Formation (lower Es3 and upper Es4) are known as two sets of effective source rocks in the Dongying Depression, Bohai Bay Basin. In this study, the saturated and aromatic steroids of 20 crude oil samples from the Dongying Depression were systematically investigated using gas chromatography–mass spectrometry (GC–MS) and GC–MS metastable reaction monitoring. Based on the distribution patterns of the steranes, norcholestanes, and triaromatic steroids, the Group I and II oils were clearly identified and shown to be derived from the lower Es3 and upper Es4 source rocks, respectively. Significantly, it was discovered that three oil samples collected from the Eocene Kongdian Formation and the Ordovician reservoirs exhibit completely different steroid and isotopic compositions from those of the Group I and II oils. These oils, as a distinct oil group (Group III), have the characteristics of abnormally high concentrations of C29 steranes, 24-nordiacholestane, 27-nordiacholestane, C28 triaromatic steroids, C27 4α-methyltriaromatic steroids, and C29 4α-methyl-24-ethyltriaromatic steroids, and low concentrations of 24-norcholestane, 27-norcholestane and triaromatic dinosteroids, and 13C depletion. Although the related source rock of Group III oils needs to be further clarified in the study area, the 13C depletion, abundant C29 steranes, and low 24-norcholestane content may suggest greater bacteria/algae inputs (e.g., green algae rather than dinoflagellates) than both the lower Es3 and upper Es4 source rocks. Identification of the Group III oils indicates that the norcholestanes and triaromatic steroids may be more effective molecular fossils for the classification of crude oils in complicated petroleum exploration fields.

Controlling the propagation direction of polarized light is crucial for optical communications and functional optical components. However, all-dielectric on-chip technology exploiting valley photon emission in transition metal dichalcogenides with enhanced emission has yet to be fully explored. Here, we report a design for enhancing valley emission and manipulating valley photon propagation based on degenerate non-radiating anapole states. By placing circularly polarized dipoles on top of a C 4 symmetric cross-slotted silicon disk, the rotating anapole state is excited with a Purcell factor up to two orders. In addition, the photon coupled to the preferred direction of the waveguide are about 2 times larger than that to the opposite direction. Our design could pave the way for realizing on-chip valley-dependent optical communication.

Abundant gas condensates have been proven in the Ordovician carbonate reservoirs in the Tazhong area, the centre of the Tarim Basin, where complicated geological evolution and multiple hydrocarbon accumulations have occurred. Property, geochemistry, and stable carbon isotopes of the Ordovician condensate are characterized to identify the oil and gas origins in the Tazhong area. Fluid inclusion data, combined with numerical modelling methods was used to determine petroleum accumulation processes. Our results suggest that oils are characterized by mixed sources, with 64% of contributions from the Middle-Upper Ordovician (O2+3) source rocks and 36% of contributions from the Lower-Middle Cambrian (Є1+2) source rocks. Gases are primarily generated from the thermal cracking of pre-existing oils in the underlying strata, with a small amount derived from kerogen cracking accompanied with oil generation. Three petroleum filling stages are determined, including the filling of the Є1+2-derived oils during the Late Hercynian period, filling of the O2+3-derived oils during the Yanshan period and oil-cracking-gas charge during the Himalayan period. The accumulation processes and relative contribution ratios of the two source rocks vary among the reservoirs and are mainly related to the transport system. Due to the lack of faults in the regions away from the No. 1 Fault Belt, the Є1+2-derived oils are difficult to fill into the Ordovician reservoirs through the gypsolyte, and thus the accumulated oils are mainly from the O2+3 source rocks. The percentage of the O2+3-derived oils is high in the southeast and northwest segments of the No. 1 Fault Belt, but relatively low in the middle segment and the vicinity of the No. 10 Structure Belt. Likewise, the late gas charge intensity is controlled by regionally varying conduit systems. Gas condensate formed in reservoirs with high gas/oil ratios. Otherwise, light oil retains with respect to low gas/oil ratios.

Neutrophil myeloperoxidase (MPO) and peroxynitrite (ONOO-) can oxidatively biodegrade carboxylated single-walled carbon nanotubes (SWCNTs). The protein-SWCNTs interactions will play an important role in the degradation and cytotoxicity of nanotubes. Here, we investigated the binding of bovine serum albumin (BSA, a common and well-characterized model blood serum protein) to SWCNTs, and found that the hydrophobic and electrostatic interactions might be crucial factors in stabilizing the binding of SWCNTs with BSA. The binding of BSA could impair SWCNTs biodegradation in vitro through the competitive adsorption to nanotube. Both SWCNTs and BSA-SWCNTs were significantly degraded in zymosan-stimulated macrophages, and the degradation degree was more for BSA-SWCNTs. The mechanism for SWCNTs degradation in activated macrophages was further investigated to demonstrate the dominant participation of MPO and ONOO--driven pathways. Moreover, binding of BSA to SWCNTs reduced cytotoxicity and degraded nanotubes induced less cytotoxicity than non-degraded nanotubes. The binding of BSA may be an important determinant for the biodegradation and cytotoxicity of SWCNTs in inflammatory cells, and therefore, provide a new route to mitigate the potential toxicity of nanotubes in future biomedical applications.

In order to study the variation of shale gas composition as well as the carbon isotopic fractionation characteristics of terrestrial shale in the Ordos Basin, and ultimately establish a prediction model for shale gas production in order to monitor production capacity and effectively manage the development of shale gas, selected core samples from production wells were obtained for desorption analyses of their corresponding gas composition and carbon isotope. The desorption results showed that the methane content of the desorption gas is relatively low, the drying coefficient (C 1 /C 1–5 ) ranges from 0.6 to 0.8, and the carbon isotope is relatively negative compared to other places. By means of the increasing desorption and production time, the drying coefficient and carbon isotope values of such samples show obvious carbon fractionation during gas adsorption/diffusion processes. The changes are more evident with increasing heavy hydrocarbons (C 2+ ) and heavier carbon isotope values. The drying coefficient shows good correlation (R 2 > 0.8) with the content of shale gas desorption per unit mass. A gas production prediction model was proposed to predict gas production throughout the life of the production well based on the relationship between the drying coefficients and gas production volume in the Ordos Basin.

With the development of optical machining and testing, the gap between freeform surface fabrication and design has been filled. Based on the freeform surfaces’ extraordinary feature for balancing asymmetric aberration and compressing system volume, an volume-compression optical design method for off-axis, three-mirror system is presented. Based on the guide of Nodal Aberration Theory for balancing asymmetric aberration, some optimization rules and tricks are shared during the optimization process. In the end, a highly-compact optical system with wide field of view, large entrance pupil and small F number is shown, the image quality is close to diffraction limit at Nyquist frequency.

The late Ordovician was a critical interval in Earth's history, during which changes in the biosphere, climate and environment occurred. In this study, we analyse the nitrogen isotope composition and multiple geochemical indices of Ordovician-Silurian (O S) shales in the Yangtze Sea (South China) to elucidate the evolution of nitrogen cycling and sedimentary environments. The nitrogen isotope values of Wufeng shale samples (Upper Ordovician) range from −0.4‰ to +1.6‰, and those of Longmaxi shale samples (Lower Silurian) range from +0.6‰ to +3.1‰. According to the longitudinal distribution of nitrogen isotope, there was a positive shift from the Wufeng Formation to Longmaxi Formation. Moreover, the redox-sensitive element ratios and nitrogen isotopes were strongly related. These relationships imply that the pre- and post-Hirnantian intervals of nitrogen cycle perturbation were directly related to changes in the oceanic redox conditions in the Yangtze Sea region. During the depositional stage of the Wufeng Formation (pre-Hirnantian) the water column was deep, causing anaerobic reduction in the sedimentary environment. The nitrogen cycle was dominated by anaerobic nitrogen fixation with little isotopic fractionation; thus, the δ15N values are light. In contrast, during the depositional stage of the Longmaxi Formation (post-Hirnantian), global cooling and tectonic uplift led to sea-level change, and sedimentation was increasingly affected by the supply of terrigenous clastic materials. The oxygen content of the water column increased, and redox stratification was maintained dynamically. Denitrification and anaerobic ammonium oxidation (anammox) played important roles in the Longmaxi Formation nitrogen cycle, leading to strong isotopic fractionation. Nitrogen isotopes are a reliable indicator of palaeo-environmental changes and have great value for the restoration of palaeo-depositional conditions and the comparative analysis of global Ordovician-Silurian geological events.

Evaporative fractionation is a complex phenomenon associated with the separation of gas from oil in the subsurface, generally involving migration fractionation and gas invasion. The concentrations and distributions of diamondoid hydrocarbons in condensate samples with different type and extent of evaporative fractionation from the Xihu Sag, East China Sea Shelf Basin were investigated to determine the effects of evaporative fractionation on diamondoid hydrocarbons. The results suggest that both migration fractionation and gas invasion can affect the concentrations and distributions of diamondoid hydrocarbons. Residual oils after migration fractionation are generally characterized by relatively high concentrations of diamondoid hydrocarbons and low methyladamantanes/methyldiamantanes (MAs/MDs) ratios. However, maturity parameters based on diamondoid hydrocarbon isomers do not vary significantly from other typical maturity parameters, suggesting that they can still be used to assess maturity. Gas invasion causes the concentrations of diamondoid hydrocarbons in oil samples to rise generally, along with methyladamantanes/methyldiamantanes (MAs/MDs) and adamantane/diamantane (A/D) ratios, indicating that the effects of gas invasion on diamondoid hydrocarbons in oils are different from those of migration fractionation. In addition, gas invasion causes some changes in the diamondoid derived maturity parameters. Thus, the effects of gas invasion should be considered when using diamondoid hydrocarbons to evaluate the thermal maturity of crude oil. Diamondoid hydrocarbon concentrations and distributions in petroleum can be affected by evaporative fractionation, suggesting that it is possible to determine evaporative fractionation according to the diamondoid hydrocarbon composition. It can be proposed that the decreasing values of MAs/MDs ratios and increase of diamondoid concentration are indicators of migration fractionation, and increasing values of A/D, MAs/MDs and diamondoid concentration might suggest the introduction of additional gas.

Mud volcanoes, as important migration channels for gases from deep to surface, are used to research chemical interactions at depth and assess petroleum accumulation. To study the post-genetic processes that change initial compositional and isotopic characteristics of reservoir gases, a large number of geochemical data of gases from mud volcanoes and adjacent oilfields in the Junggar Basin have been selected and analyzed. Compared with the homologous reservoir gases, the seeping gases performed in mud volcanoes generally have the following characteristics: (1) dryness coefficients (C1/C1-4) significantly increase; (2) methane tends to become depleted in 13C; (3) propane tends to become enriched in 13C. Through geochemical and microbial analyses, it is proved that the reservoir gases belong to thermogenic coal-gases, which are originated from the Lower-Middle Jurassic source rocks. After discharging from reservoirs, the gases migrated and diffused upward to the mud volcanoes, and methane anaerobic oxidation might occur between reservoir and surface. However, due to the migration advection and effusion, it reveals the obvious isotopic and molecular fractionation with the dry coefficient increasing (loss of C2+ alkanes) and methane carbon isotope lightening, which covers the weak anaerobic oxidation of methane. In addition, oxidation by ferric (Fe3+) - bearing minerals may also lead to the significant depletion of 13C in methane, and iron-bearing minerals have been reduced. Propane tends to become enriched in 13C, mainly results from that sulfate-reducing bacteria prefers to use propane as growth substrates rather than ethane, and preferentially oxidizes propane. The results including the gas geneses and its secondary post-genetic processes may offer important insight into the evaluation of the related hydrocarbon resources, especially the unexplored regions.

In this paper, a novel sensing platform based on MoO3-polypyrrole nanowires /MWCNTs (MoO3-PPy NWs/MWCNTs) composite was developed for electrochemical detection of luteolin, a widely used antitumoral agent. One dimensional (1D) MoO3 NWs were synthesized by hydrothermal method, which shows a large specific surface area. PPy coating on the surface of MoO3 NWs not only increases the electrical conductivity of MoO3, but also prevents the aggregation of MoO3 NWs. MWCNTs serves as electrical conducting wires that connect MoO3-PPy NWs coaxial heterostructure NWs, which is beneficial to promote the transfer of electrons and the redox performance of catalyst. Due to the excellent synergic effect between MoO3-PPy NWs and MWCNTs, the sensor based on MoO3-PPy NWs/MWCNTs can detect luteolin with low limit of detection (LOD) down to 0.03 nM. Additionally, outstanding long-term stability, excellent selectivity and prominent reproducibility were obtained. Furthermore, luteolin in real samples was detected by the proposed sensor with good performance. The sensor based on MoO3-PPy NWs/MWCNTs provides a wide linear response ranging from 0.1 nM to 10.0 μM and a low limit of detection (LOD) of 0.03 nM (S/N = 3) for luteolin. The method has been applied to detect luteolin in chrysanthemum tea with recoveries of 96.00–108.20% and RSDs of 3.39–4.02% (n = 4).

In total, 2.37 million tons of marine crude oil originating from mixed source rocks has been discovered in the Tarim basin. Geological and geochemical analyses have confirmed that these mixed hydrocarbons are mainly from two sets of source rocks, including the Cambrian – Lower Ordovician and Middle-Upper Ordovician hydrocarbon source rocks. In this study, we determined the set of source rocks primarily responsible for the mixed hydrocarbons and the next location to be explored. Differences in n-alkane carbon isotopes in end-member oils from Cambrian–Lower Ordovician and Middle-Upper Ordovician source rocks were examined. A material balance model and simulation methods were used to evaluate the relative amounts contributed by each source. The results from known reserves in the Tazhong area show that the mixing ratio or contribution is up to 65% from Cambrian–Lower Ordovician source rocks and is generally higher than that from Middle-Upper Ordovician source rocks. The discovery of deep hydrocarbons has caused the total oil contribution from the Cambrian–Lower Ordovician to increase. The mixing ratio of Cambrian–Lower Ordovician oil varies depending on the well, formation, and block. It increases from west to east horizontally and from top to bottom vertically. Hydrocarbons from Cambrian–Lower Ordovician source rocks migrate upward along faults, and the mixing ratio decreases as the distance from the oil source fault increases. Favorable areas for Cambrian–Lower Ordovician hydrocarbon exploration are deep layers and areas near the fault zone that are connected to deep layers. The material balance model for carbon isotopes and evaluation methods for relative contributions considered differences in relative concentration and carbon isotope structure of n-alkanes. Herein, new methods for the identification and evaluation of hydrocarbons in the petroleum system of this superimposed basin are presented.

The binding of protein to carboxylated single-walled carbon nanotubes (SWCNTs) was believed to play an important role in the biological effects of nanotubes. However, the effects of protein-SWCNTs interactions on the oxidative degradation of nanotubes were not stressed enough. Here, we investigated the binding of human immunoglobulin G (IgG) to SWCNTs, and found that the preferred binding site was located in the Fc region of IgG. The hydrophobic and electrostatic interactions might be the crucial factors in stabilizing the binding of SWCNTs with IgG. Through the competitive binding of IgG and myeloperoxidase (MPO) to nanotube surfaces, the binding of IgG could impair MPO-induced SWCNTs biodegradation in vitro. However, both SWCNTs and IgG-SWCNTs were significantly degraded in zymosan-stimulated neutrophils, and the degradation degree was more for IgG-SWCNTs. These results suggest that the binding of IgG may be an important determinant for MPO-mediated SWCNTs biodegradation in activated human inflammatory cells.

The high heme content in red meat is associated with an increased risk of developing cancer. Pharmacologic concentrations of ascorbate can specifically kill a wide range of cancer cells. In this study, the impact of ascorbate at pharmacologic concentrations on hemoglobin (Hb)-modulated human hepatoma HepG2 cell survival was investigated. It was found that HepG2 cells were proliferated by Hb (5⿿25 μM), but killed by high pharmacologic concentrations of ascorbate (2⿿10 mM). Although ascorbate at the low pharmacologic concentration (0.5 mM) alone exhibited insignificant effect on cell viability, it effectively inhibited Hb (10 μM)-induced cancer cell proliferation. The mechanism of this cytotoxicity was based on the production of extracellular H 2 O 2 and involved transition iron. The influence of ascorbate on Hb-dependent redox reactions (i.e. the oxidative stability of Hb and its cytotoxic ferryl intermediate) was further investigated to illustrate the reaction mechanism of ascorbate toxicity, where H 2 O 2 was generated in the reaction of ascorbate with Hb. Furthermore, circular dichroism demonstrated no significant change in the secondary structure of Hb after ascorbate addition and molecular docking revealed binding modes of ascorbate with Hb. These results demonstrated that ascorbate could possess anti-cancer activity through interfering in Hb-dependent redox reactions.

The structural details and flexibilities of protein impose significant challenges to develop protein imprint, especially for the selection of functional monomer. Using NAMD, AutoDock 4 and AutoDock Vina, we investigated the formation of a high performance protein imprint on a nanosensor that detected human papillomavirus (HPV) biomarker protein E7 with high sensitivity. According to molecular dynamics, the phenolic oligomers were shown to assemble with the E7 protein and form a complex at specific targeting areas on the protein. Docking analysis efficiently screened chemical compounds by evaluating the binding affinity. A new parameter, i.e., average binding energy (ΔG/contact), was used together with binding energy (ΔG) to screen compounds. The screening went through 189 compounds and identified a subpopulation of 22 compounds showing unique characteristics of binding, and could potentially be used to develop the specific and robust imprint. Accordingly, the study implicated a novel approach to screen functional compounds for rational design of the protein imprint. Keywords: Molecular imprint, Rational design, Nanosensor, Electropolymerization, Biorecognition, Carbon nanotube, Docking, Molecular dynamics

A series of integrated and repeatable methods were used to demonstrate the methane adsorption limitations associated with calculating low thermal maturity shale gas adsorption capacities. These methods include X-ray diffraction of bulk and clay minerals, Soxhlet extraction, Ar-ion polishing, focused ion beam scanning electron microscopy (FIB-SEM), low pressure N 2 adsorption and high pressure CH 4 adsorption. The laboratory data suggest that the Yanchang Formation shale primarily consists of clay minerals (≈47.4%) and detrital minerals (≈51.1%). An illite–smectite mixed layer is the principal clay mineral constituent, while quartz is the major detrital mineral component. The thermal maturity is relatively low with Ro ranging from 0.84%Ro to 1.1%Ro, suggesting the absence of organic matter pores and the presence of soxhlet-extractable bitumen and oil, which clog pores with diameters around 4 nm and 50 nm. The specific surface areas and quantities of adsorbed N 2 significantly higher for samples extracted using a mixed solution (CH 2 Cl 2 and CH 3 OH) compared to non-extracted samples. However, the methane adsorption volumes, including volume that were measured and calculated using Langmuir fitting parameters, minimally varied during high pressure CH 4 adsorption experiments. CH 4 dissolution in bitumen and oil causes the difference exhibited by these two gas adsorption analyses. Non-extracted samples produce inaccurate results using methane adsorption procedures and do not effectively represent practical shale reservoirs. Extracted samples are limited by CH 4 adsorption when calculating gas adsorption capacities for low thermal maturity shales.

The total components and isotopes of rare gases as well as hydrocarbon gases for Dabei gas field are analyzed firstly, then their geochemical characteristics and genesis are discussed respectively, finally gas source correlation and their contributions are evaluated. The research results show that: (1) In Dabei gas field, methane is the main component, accompanying with a few N2 and CO2, as well as extremely low rare gases. In total component contents of rare gases, the He content is from 56.0 to 60.4 ppm with an average of 57.8 ppm and generally 1 order of magnitude higher than the air content value, while the Ne, Ar, Kr, and Xe contents are generally 1–3 orders of magnitude lower than the corresponding air content values. (2) The δ13C1 value in Dabei gas field usually ranges from −31.9‰ to −29.4‰. The δ13C2 value generally ranges from −24.2‰ to −19.4‰, which is obviously heavier than −28.5‰, The natural gases in Dabei gas field can be identified as typical coal-formed gas. (3) The 3He/4He value in natural gases is generally from (6.31–11.24) × 10−8 with an average value of 8.42 × 10−8. The 20Ne/22Ne value is from 9.563 to 9.734, and the 21Ne/22Ne value is from 0.0298 to 0.0307. The 40Ar/36Ar value is usually from 390 to 858 with an average value of 552, and the 38Ar/36Ar value is from 0.1955 to 0.2035. The 129Xe is relative loss, while the 132Xe is relative surplus. The comprehensive genesis identifications of He, Ne, Ar, and Xe indicate that rare gases are crustal derived genesis, mainly originating from the decay of related radioactive elements in crust. (4) The gas source correlation indicates that the natural gases in Dabei gas field are originated from humic coal series source rocks of Triassic-Jurassic, mainly contributed by Jurassic in vertical strata and coal rocks in type, coal rocks accounting for 63% and mudstones accounting for 37%.

The role of the residual bitumen in the shale gas storage capacity is investigated for potential terrestrial shale gas reservoirs in the Yanchang area, southern Ordos Basin, China. The Upper Triassic organic-rich Yanchang shales comprise of thermally mature Chang 7 Shale (average TOC 5.12 wt.%, Type I–II1 kerogen, Tmax 443–458 °C, Ro 0.83%–1.02%) and relatively mature Chang 9 Shale (average TOC 4.40 wt.%, Type I–II1 kerogen, Tmax 443–476 °C, Ro 0.88%–1.10%). The mineralogy of Yanchang shales is dominated by clay minerals (average 48.85%) and quarts (average 31.7%). A series of low pressure nitrogen adsorption/desorption and high pressure methane sorption experiments were conducted on pretreated fresh drilling cores (including three groups of core samples: one original group, one group extracted by dichloromethane and the other group extracted by trichloromethane) selected from Yanchang shales to demonstrate the role of the residual bitumen in the shale gas potential. Low pressure nitrogen sorption method was used to elucidate the effect of the residual bitumen on the pore structure of Yanchang Shales. The results show that the specific surface area and pore volume and pore surface area of shale samples after the extraction greatly increase and their growth was closely related with pores of >30 nm and

The carbon isotopic composition of sedimentary organic matter (δ13COM) is notably important for the genetic identification of source rock and its products. The sapropelic organic matter (mostly plankton with high hydrogen index) is generally depleted in 13C as compared to humic organic matter (mainly higher plants with lower hydrogen index). However, some lacustrine sediments contain sapropelic source rocks with anomalous 13C-enriched isotopic ratios, especially reported in freshwater lakes. The purpose of this study is to discuss the geneses of lacustrine sedimentary organic matter characterized by anomalous 13C-enriched ratios in saline and freshwater sediments. To this end, we integrate the detailed organic geochemical data (including Rock-Eval analysis data, total organic carbon contents, total organic carbon isotopic compositions, biomarkers, and trace element concentrations) of 64 saline lake sediments and 39 freshwater lake sediments obtained from the Paleogene Shahejie Formation of Dongpu sag and Qikou sag, separately, in Bohai Bay Basin of eastern China. Both sags exist samples with high hydrogen index values (HI > 400 mg/g) and high total organic carbon contents (TOC > 2%), but anomalous 13C-enriched isotopic ratios (up to −21.1‰). In Qikou sag, the δ13COM values of sapropelic kerogen correlate positively with TOC contents. The anomalous enrichment of 13C in organic matter is associated with extremely high productivity of algae, such as algae bloom. In Dongpu sag, the enrichment of 13C in organic matter is attributed to the significant increase of drought and salinity. High salinity and aridity climate may lead to the abundance of C4 plants and Chlorobium as well as the enrichment of 13C in plankton.

In this study, we report new analyses of stable nitrogen isotopic compositions (δ15N) of the black mudstones from the Chang-7 Member of the Upper Triassic Yanchang Formation in the Ordos Basin, China, to examine the possible linkage of such isotopic compositions with the depositional environment. These mudstones were deposited mainly under suboxic bottom water column conditions. The core descriptions and trace element concentrations differ between samples obtained from the Chang-73 and Chang-71,2 members, situated at the bottom and top of the Chang-7 Member, respectively, such that the depositional condition of the former implies a more reduced water regime. The bulk rock nitrogen isotope (δ15Nbulk) values of the samples obtained from the Chang-73 Member are higher than those of the Chang-71,2 Member. No significant differences were identified in the organic carbon isotopes (δ13Corg), total organic carbon (TOC), or total nitrogen (TN) values between the two units. The results of δ15Nbulk cross-plotting with the TOC, TN, and carbon to nitrogen atomic ratio (C/N) show an absence of significant modification of the primary nitrogen isotopic compositions from post-depositional processes. Given the depositional history of these units, we suggest that the sedimentary redox environment can have a significant influence on δ15Nbulk. Denitrification, which occurs mainly in suboxic conditions, plays an important role in such an environment, resulting in 15N enrichment during the original deposition. Thus, owing to its sensitivity to sedimentary redox environments, the δ15Nbulk index can be an effective tool for evaluating depositional redox conditions, particularly for further subdivision of suboxic environments.

From the nodal aberration theory, aberration nodes will move to other locations of field of view when the optical element is decentered or tilted in rotationally symmetric system, which will lead to uncorrected off-axis aberration at locations of large field of view; cause the terms of wavefront aberration function are linked directly to the terms of Zernike polynomials, the aberrated wavefront of the system can be fitted by Zernike polynomials. At the same time, specific terms of Zernike polynomials can be selected to correct wavefront aberration efficiently by evaluating full-field display. Based on the method above, an off-axis optical system with field of view of 3°×3°is designed with two freeform surfaces and one aspheric surface, and certain Zernike polynomials are chosen as the descriptor of freeform surfaces. Keywords:Nodal aberration theory, freeform surface, Zernike polynomials, full-field display.

Maintaining colloidal stability in unfriendly environments while retaining surface chemical properties is challenging for fundamental science and crucial for many applications. Here, we report for the first time that by using a low concentration of poly(sodium 4-styrenesulfonate) (PSS), graphene-based amphiphilic Janus nanosheets (AJNs) can be stabilized in high salt brine (3 wt % NaCl and 0.5 wt % CaCl2), whereas the interfacial behavior of the nanosheets is not affected. The adsorption of PSS on the hydrophilic and hydrophobic surfaces of AJNs in brine was investigated experimentally and by molecular dynamics simulations. Simulations further showed that the spatial configuration of absorbed PSS molecules with sulfonate functional groups facing outward favored the generation of electrosteric repulsive interactions. Calculations of the interaction energy between PSS molecules and the nanosheet revealed surface charge as a key parameter to stabilize AJNs in the salt environment, as demonstrated by the case...

It is shown in natural gas proportion mixing experiments that a mixed-source natural gas is the physical combination of end member gas. Both the carbon and hydrogen isotopes in the mixed-source natural gas can be expressed by the weighted average of corresponding components content and isotopes of end member gas. Under certain geological setting, the selection of end member gas is the key to mixed-source ratio calculation. Then, it's better to estimate the mixed-source ratio with δ13C1 and component data according to the weighted average calculation formula. The analysis on natural gas geochemistry characteristics show that the natural gas extracted from Jingbian Gas Field in the Ordos Basin is mainly an upper Paleozoic coal-derived gas. In the analysis of geological conditions for reservoir forming and characteristics of natural gas, natural gas from Longtan 1 Well and Tao 6 Well were selected as the end member gases of lower Paleozoic oil-type gas and upper Paleozoic coal-type gas respectively to calculate the mixed-source ratio of natural gas in Jingbian Gas Field. The ratio of upper Paleozoic coal-derived gas mostly accounts for over 70% and its average ratio reaches 81%. Therefore, the exploration of natural gas of Ordos Basin should be focused on the upper palaeozoic coal source rock, and attention should be paid to the matching of coal source rock in the exploration of weathered crust gas deposit.

With wells Puguang 2 and 6 in the Puguang gas field as the research objects by choosing organic carbon as characterization reservoir carbon (indirectly reflecting the bitumen contents), this paper discusses the relationship between bitumen contents and lithologic characteristics, reservoir characteristics, and calculates the volume of paleooil and oil cracked gas. The study shows that the organic carbon contents of the reservoirs are related to lithologic characteristics. Due to variations in the particle size or structure of rocks, the porosity of the reservoirs varies, furthermore, it will influence the contents of organic carbon. And the relationship between these two parameters is positive. Based on the analysis, the relationship between total organic carbon (TOC) and the contents of reservoir bitumen also appears to be positive. The volume of paleo-oil and cracked gas of the Changxing-Feixian’guan Formation are respectively 495 million tons and 360.4 billion m3 through the calculation of reservoir’s organic carbon. Therefore, the relationship between carbon-bearing rate and characteristics of the reservoirs can be used to indirectly evaluate reservoir types. Besides, the carbon-bearing rate of the reservoirs also reflects the contents of reservoir bitumen, paleo-oil as well as natural gas. It makes a new approach for the study of the types of reservoirs and the amounts of paleo-oil and oil cracked gas in northeastern Sichuan Basin.

Based on gas chromatography and gas chromatography mass spectrometry techniques, the authors examined biomarker characteristics of the Ganquan Formation source rocks in the area of Dahulishan, Ejina, and analyzed the information and petroleum geological significance that were indicated by the source of organic matter, sedimentary environment and maturity and so on. Gas chromatography peak of saturated hydrocarbons from the Ganquan Formation source rocks showed “the former peak” of the single peak distribution, the main peak of carbon being C18, indicating the main sources of organic matter with marine organic matter. Pr/Ph ranges from 0.3 to 0.6, indicating a strongly reducing sedimentary environment. Biomarker assemblages of the Ganquan Formation source rocks are abundant in tricyclic terpane with long side chains, with a high level of gammacerane, showing dominant distribution of C27 sterane. High contents of gammacerane in organic matter show organic facies of source rocks in the saltwater sedimentary environment. That average hopane/sterane ratio is 0.59, showing that algae have made more contributions to organic matter than bacteria. And the high level of C27 steranes shows that algae are the main source of hydrocarbon precursors. The Ganquan Formation’s methylphenanthrene index, which is an effective molecular parameter index to measure thermal evolution of organic matter, ranges from 0.35 to 0.50, and the conversion of vitrinite reflectance Rc from it is within the range of 2.00–2.09, indicating that the Ganquan Formation source rocks are in the over-mature stage of thermal evolution.

The biodegradation of crude oil by microorganisms from well Luo-801, China, was examined in cultures grown under conditions that promoted either methanogenesis or sulfate reduction, at 35 °C and 55 °C. Headspace gas and oil compositions were characterized at 180 d and 540 d. Alkylphenanthrenes are relatively recalcitrant to bacterial attack and the biodegradation of these compounds appeared to be insignificant after 180 d under both conditions, but is evident after 540 d. The depletion of alkylphenanthrenes was monitored through evaluation of the ratio of alkylphenanthrenes to the most bioresistant, analyzed component (C 28 20R triaromatic steroid hydrocarbon) and isomer susceptibility also was evaluated by relative abundance comparison within the compound class. The influence of growth temperature varied. Only slight differences in alkylphenanthrene concentrations were observed after 180 d whereas the greater degrees of biodegradation were observed at 35 °C in the methanogenic culture and at 55 °C in the sulfate reducing culture. Overall, higher biodegradation rates occur under sulfate reducing condition, which is consistent with the conclusion that methanogens are generally less able to compete for substrates than sulfate reducers. The biodegradation susceptibility of alkylphenanthrenes decreases with increasing degree of alkylation, i.e., phenanthrene (P) and methylphenanthrenes (MPs) were more easily biodegradable than C 2 -alkylphenanthrenes (C 2 -Ps) and C 3 -alkylphenanthrenes (C 3 -Ps). Biodegradation selectivity for specific homologues is not striking for the limited time duration of the experiments. However, 3-MP seems slightly more vulnerable than other methylphenanthrene isomers and 1,7-DMP has slightly higher ability to resist biodegradation than the other C 2 -P isomers. The commonly used thermal maturity parameters derived from methylphenanthrene isomer ratios are altered insignificantly by biodegradation and remain valid for geochemical assessment. This information should be useful for assessing the limits of in situ crude oil biodegradation.

Previous studies have shown that carboxylated single-walled carbon nanotubes (SWCNTs) could be oxidatively biodegraded by neutrophil myeloperoxidase (MPO) and peroxynitrite (ONOO-). However, the biodegradation mechanism of nanotubes in macrophages has not been explored enough. Here, we showed that both MPO and ONOO- could effectively oxidize SWCNTs to generate shorter and oxidative nanotubes in vitro. SWCNTs were significantly degraded in zymosan-stimulated macrophages, and the degradation mechanism was dependent on MPO and ONOO--driven oxidative pathways of activated macrophages, where NADPH oxidase was found to be a major determinant of the biodegradation process. Moreover, the functionalization of IgG to SWCNTs could stimulate MPO release and ONOO- formation in macrophages, thereby creating the conditions favorable for degradation of nanotubes and subsequently contributing to the higher degradation degree of IgG-coated SWCNTs. Therefore, our discovery of NADPH oxidase-dependent SWCNTs degradation in activated macrophages will open new opportunities for the regulation of SWCNTs fate in vivo.

To explore the effectiveness of UC ultra-congruent rotating platform prosthesis in the treatment of knee osteoarthritis by comparing with fixed-bearing implant.The clinical data were retrospectively analyzed, from 98 patients (98 knees) with knee osteoarthritis undergoing primary total knee arthroplasty between January 2011 and December 2012. The UC ultra-congruent rotating platform prosthesis was used in 56 cases (mobile-bearing group) and fixed-bearing implant was used in 42 cases (fixed-bearing group). There was no significant difference in gender, age, side, weight, disease duration, grading of arthritis, the number of varus and valgus malformation, preoperative range of motion of the knee, the Knee Society Score (KSS) score, the visual analogue scale (VAS) score, femorotibial angle, tibial angle, and articular surface angle between 2 groups (P0.05). The operation time (including anesthetic time), intraoperative blood loss, hospitalization time, total hospitalization expenses, postoperative range of motion of the knee, the KSS score, and the VAS score were compared. The femorotibial angle, tibial angle, and articular surface angle were measured on the basis of anteroposterior and lateral X-ray films, and prosthesis loosening was observed.There was no significant difference in the operation time, intraoperative blood loss, and hospitalization time between 2 groups (P0.05), while the total hospitalization expenses of fixed-bearing group were significantly lower than those of the mobile-bearing group (t = 8.506, P = 0.000). The patients were followed up 16-30 months in the mobile-bearing group, and for 16-38 months in the fixed-bearing group. Postoperative complications occurred in 3 cases (7.14%) of the fixed-bearing group (1 case of fat liquefaction of incision, 1 case of joint stiff, and 1 case of anterior knee pain), and in 3 cases (5.36%) of the mobile-bearing group (1 case of delayed wound healing, and 2 cases of anterior knee pain); there was no significant difference in the complication rate between 2 groups (χ2 = 0.133, P = 0.516). At last follow-up, the KSS score, VAS score, range of motion of the knee, femorotibial angle, tibial angle, and articular surface angle were superior significantly to those before operation in both groups (P0.05), but no significant difference was found between 2 groups (P0.05). No radiographic signs of radiolucent line, prosthetic dislocation, patellar dislocation, prosthetic loosening, and fracture was found.UC ultra-congruent rotating platform prosthesis in the treatment of knee osteoarthritis can effectively improve the knee joint function and relief pain, which has the same short-term effectiveness in fixed bearing implant.