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Purpose We evaluated the diagnostic performance of the texture features of dynamic contrast-enhanced (DCE) MRI for breast cancer diagnosis in which the discriminator was optimized, so that the specificity was maximized via the restriction of the negative predictive value (NPV) to greater than 98%. Methods Histologically proven benign and malignant mass lesions of DCE MRI were enrolled retrospectively. Training and testing sets consist of 166 masses (49 benign, 117 malignant) and 50 masses (15 benign, 35 malignant), respectively. Lesions were classified via MRI review by a radiologist into 4 shape types: smooth (S-type, 34 masses in training set and 8 masses in testing set), irregular without rim-enhancement (I-type, 60 in training and 14 in testing), irregular with rim-enhancement (R-type, 56 in training and 22 in testing), and spicula (16 in training and 6 in testing). Spicula were immediately classified as malignant. For the remaining masses, 298 texture features were calculated using a parametric map of DCE MRI in 3D mass regions. Masses were classified into malignant or benign using two thresholds on a feature pair. On the training set, several feature pairs and their thresholds were selected and optimized for each mass shape type to maximize specificity with the restriction of NPV > 98%. NPV and specificity were computed using the testing set by comparison with histopathologic results and averaged on the selected feature pairs. Results In the training set, 27, 12, and 15 texture feature pairs are selected for S-type, I-type, and R-type masses, respectively, and thresholds are determined. In the testing set, average NPV and specificity using the selected texture features were 99.0% and 45.2%, respectively, compared to the NPV (85.7%) and specificity (40.0%) in visually assessed MRI category-based diagnosis. Conclusion We, therefore, suggest that the NPV of our texture-based features method described performs similarly to or greater than the NPV of the MRI category-based diagnosis.

In the present study, we aimed to purify and characterize LuxG obtained from Photobacterium leiognathi YL and examine its improvement for NADH detection. To this end, we cloned and expressed the putative luxG gene of P. leiognathi YL in the Escherichia coli BL21 strain. The product of luxG is a flavin reductase that consists of 206 amino acids, corresponding to a subunit molecular mass of ∼26 kDa. Phylogenetic analysis demonstrated that P. leiognathi YL LuxG has a rather distant evolutionary relationship with Frase I of Aliivibrio fischeri and Frp of Vibrio harveyi, but a close evolutionary relationship with Fre from Escherichia coli, which are all enzymes related to oxido-reductase. Further comparison shows that the changes in the functionally conserved sites may contribute to the functional divergence of LuxG and Fre. LuxG could supply reduced flavin mononucleotide (FMN) for bacterial luminescence by catalyzing the oxidation of nicotinamide adenine dinucleotide hydrogen (NADH). Based on this, a coupled pure enzyme bioluminescent system was established and used for NADH detection. The NADH samples with concentrations of 0.1-1 nM were used to validate the linear relationship, and it was found that the logarithmic deviations were less than 3%, which showed more sensitive and stable results than the NADH detection by recombinant E. coli including the exogenously expressed luciferase and intrinsic Fre. Investigation of P. leiognathi YL LuxG would provide a basic understanding of its evolution, and structural and functional properties, which might contribute to the development of a NADH detection kit in the future.

Tazhong and four other well-known TSR-altered petroleum reservoirs from around the world were analyzed for their molecular and carbon isotopic compositions of saturated hydrocarbons, thiaadamantanes concentrations or H2S contents to determine the relative stability of saturated hydrocarbons during thermochemical sulfate reduction (TSR). We find that TSR does not preferentially deplete tricyclic terpanes and 17α, 21β hopanes with the “exposed” tertiary carbon atoms compared to 18α (H)-22, 29, 30-trisnorhopane (Ts) and C29Ts that have no tertiary carbon atoms, as proposed by Xia and Gong [35] . However, pristane (Pr) and phytane (Ph) seem to have been preferentially oxidized over normal C17 and C18 alkanes, respectively, resulting in decreasing Pr/nC17 and Ph/nC18 ratios with increasing extent of TSR for the Tazhong and Nisku oils and condensates. iC4 appears to be preferentially depleted relative to nC4 during early TSR stage. At later TSR stage both nC3 and nC4 are oxidized more readily than iC4 in the Mobile Bay Norphlet Formation condensates. Thus, we tentatively propose that relative oxidization order during TSR may start with long chain iso-alkanes followed by n-alkanes, then cycloalkanes, C2-C4 alkanes and finally methane; however, it seems that oxidization of these compounds overlaps significantly.

The abundance of 2-thiadiamondoids is currently utilized to assess the extent of thermochemical sulfate reduction (TSR). However, these compounds are ultimately degraded to small molecules with increasing temperature in deep hot reservoirs, resulting in uncertainty in their use as a proxy to evaluate the extent of TSR. In this study, the thermal stability of 2-thiadiamondoids was determined from variations in their abundance upon pyrolysis at different temperatures using an oil enriched in thiadiamondoids. The results demonstrated that these compounds were generally stable at Easy%Ro ≤ 1.0, followed by partial destruction at Easy%Ro = 1.3–2.0 and intensive decomposition at Easy%Ro ≥ 2.0–2.3, suggesting the potential underestimation of the TSR extent at the highly mature to over mature stages. The thermal stability of 2-thiadiamondoids and diamondoids strongly depended on their cage numbers, which presented an increasing trend with higher cage numbers. However, diamondoids were far more stable than 2-thiadiamondoids and were still thermally stable even up to Easy%Ro = 1.8–2.3. The thermal stability of dibenzothiophenes (DBTs) showed a decreasing trend with increases in alkyl substituted carbon numbers. They were thermally stable at Easy%Ro ≤ 1.0–1.8 and can be seriously cracked at Easy%Ro ≥ 1.8–3.0. The C0-DBT and C1-DBTs were more stable than thiadiamondoids, but C3-DBTs showed the opposite trend. The thermal stability of gasoline range hydrocarbons showed a trend of CH4 > C2H6 > C3H8 > C4–5. CH4 and C2H6 were much more stable than diamondoids, while C3–5 hydrocarbons were only thermally stable at Easy%Ro ≤ 1.8–2.3 and severely degraded at Easy%Ro ≥ 2.6–3.0. The C3H8 and 2-cage diamantanes, C4–5 compounds and 1-cage adamantanes had a similar thermal stability. Therefore, to accurately assess the TSR extent should be made using thiadiamondoids, diamondoids and C0–1-DBTs, even gasoline range hydrocarbons, rather than thiadiamondoids alone, if gases are well preserved within petroleum reservoirs in the subsurface.

The blast furnace campaign length is today usually restricted by the hearth life, which is strongly related to the drainage and behavior of the coke bed in the hearth, usually referred to as the dead man. Because the hearth is inaccessible and the conditions are complex, knowledge and understanding of the state of the dead man are still limited compared to other parts of the blast furnace process. Since a number of publications have studied different aspects of the dead man in the literature, the purpose of the current review is to compile the findings and knowledge in a comprehensive document. We mainly focus on contributions with respect to the dead man state, and those assessing its influence on the hearth performance in terms of liquid flow patterns, lining wear and drainage behavior. A set of common modeling approaches in this specific furnace area is also briefly presented. The aim of the review is also to deepen the understanding and stimulate further research on open questions related to the dead man in the blast furnace hearth.

Improved understanding of the reservoir mineral effects on the occurrence of thermochemical sulfate reduction (TSR) and possible mechanisms is critical for petroleum exploration and production. A series of hydrous pyrolysis experiments were conducted with and without the presence of montmorillonite, illite and quartz (silicates), calcite and dolomite (carbonates) at 360 °C and 50 MPa for 12 h, 48 h and 312 h. Gaseous compounds, C7–8 light hydrocarbons, n-C9+ and organic sulfur compounds as well as compound-specific δ34S analysis were conducted subsequently. The results show that with the heating time increasing or TSR advancing, n–C9+ decrease gradually accompanied by the increases of TSR products, H2S, alkylbenzenes, benzothiophenes (BTs) and dibenzothiophenes (DBTs). The δ34S values of BTs and DBTs progressively approached that of MgSO4 and the difference in their average δ34S values (Δ34SBT-DBT) decreased. Compared to experiments with the absence of minerals, the experiments with silicates, in particular montmorillonite, are depleted in n–C9+ and enriched in H2S, light monoaromatics and organosulfur compounds and smaller Δ34SBT-DBT. Experiments with carbonates demonstrated the opposite trend. This indicates that silicates, in particular montmorillonite, accelerated TSR rates while carbonates reduced them. Under the experimental conditions, the exchange cations within montmorillonite and on the surface of clays and talc precipitation can increase the concentrations of H+ and hence HSO4− and then catalyze the generation of isoalkanes, which are prone to be oxidized in TSR. This can reduce the activation energy required for the occurrence of TSR. It might therefore be possible for TSR to occur at relatively low temperatures in silicate reservoirs and source rocks in natural environments. Carbonate dissolution can reduce the concentrations of H+ and HSO4−, and hence reduce the TSR rates. This study demonstrates the importance of minerals in regulating the TSR occurrence and suggests that TSR can occur in siliciclasitic as well as carbonate formations in nature. Therefore, the significance of minerals should be considered in the evaluation of TSR and sour gas risk in TSR-altered hydrocarbon accumulations in different geological contexts.

Cloning of genes encoding the luciferase from Photobacterium leiognathi YL in Escherichia coli Rosetta (DE3) was performed successfully and the expressed forms of lux AB were purified to homogeneity. Experimental measurements revealed that luciferase from Photobacterium leiognathi YL has good thermal stability and a high residual activity at extreme pH values, which are extremely important for its various ecological, industrial and medical applications. Furthermore, we made a first attempt for quantitative detection of NADH by recombinant E. coli Rosetta (DE3) coupled enzyme system. A good linear relationship between luminescence intensity and NADH with low (1-12 nmol/L) and high (10-500 nmol/L) concentration was observed, whose standard curve was y = 772.97× + 4041.1, R2 = 0.9884 and y = 1710× + 4.99 × 105 , R2 = 0.9727, respectively. Our results demonstrate a high sensitivity of recombinant E. coli coupled enzyme system to NADH on the basis of high soluble expression of recombinant luciferase and continuous and stable expression of some NAD(P)H-dependent flavin mononucleotide (FMN) reductases.

A shale reservoir, generally rich in organic matter (OM) and clay minerals, is a heterogeneous porous medium with mixed wettability. It remains challenging to quantify matrix pores within organics and clays and to further understand how water interacts with them. By using nitrogen/carbon dioxide and water vapor sorption analyses, we carried out a comparative study about pore structure and hydration behavior in a set of overmature marine shale samples as well as their OM-free aliquots. The results show that OM porosity occupies 33% of OM volume and contributes 28–67% of total porosity. The majority of OM porosity and 23–73% of inorganic porosity are located in pores with a width of less than 10 nm. Water-derived pore size distribution (PSD), computed using the Kelvin equation, generates greater pore volume than nitrogen-derived PSD, and this gap is positively affected by total clay content and shrinks as the pore size increases. Although the water has strong dipole and resulting specific interactions with surfaces, water coupled with nitrogen/carbon dioxide as probe molecules could provide important and complementary pore information. Furthermore, the response of water-derived PSD to OM loss demonstrates that small OM pores (

This paper reports bulk organic carbon isotope data from a laboratory study designed to evaluate whether acid chromium reduction (ACR), commonly used to prepare rock/sediment samples for sulfur isotope analysis, significantly fractionates bulk organic carbon isotopes compared with the standard decarbonation (SD) method in Quaternary coastal plain incised valley sediments. In this study, 36 sediment samples obtained from a Quaternary sediment core from the Qiantang River incised valley on the East China coastal plain were tested. The results show differences in the δ13Corg values between the ACR and SD methods for Quaternary incised valley sediments ranging from – 0.97‰ to +0.34‰, with most values (86%) showing a negative bias. Approximately half of the samples yield δ13Corg values that differ by ≥ ± 0.3‰. The carbonate and total organic carbon (TOC) contents of the sediment samples have no significant effects on the bulk organic carbon isotopes derived by ACR. There is also no obvious correlation between the organic carbon loss by ACR and the difference of the δ13Corg values. We believe that ACR loses more 13C-enriched labile organic carbon and/or volatile organic compounds (VOCs) than SD, which leads to a negative bias in the δ13Corg values. The mineral composition was speculated to be related to a significant positive bias in the δ13Corg values by ACR observed in two particular samples and requires further study. Consequently, ACR should be used with caution for sediments containing primarily young labile organic carbon with medium to high TOC contents (TOC ≥ 0.5 wt %), as it may cause a large offset of the δ13Corg values compared with SD. However, ACR may be used for sediments containing organic matter primarily from terrestrial plants with relatively low TOC contents (TOC

Improved understanding of the hydrogen sulfide (H2S) origins is of significant importance for petroleum exploration, exploitation and refinement due to it being highly toxic and corrosive. H2S was discovered from the Qianjiang Formation (Eq) in the northern area and Xinggouzui Formation (Ex) in the southern area of the Qianjiang Depression, Jianghan Basin, China. The sulfur isotopic compositions of H2S, water-dissolved sulfates and oils and chemical compositions of volatile organic sulfur compounds (VOSCs) in natural gas as well as molecular and stable carbon isotopic compositions of oil and gas samples were measured to decipher the specific generation pathways of H2S. The conventional wisdom relays on bacteria sulfate reduction (BSR) for producing H2S because of the current low thermal regime (

Water sorption provides a great approach to understand water-shale interaction. In this research, water sorption isotherms of fourteen Wufeng-Longmaxi shale samples collected from the eastern Sichuan Basin of China were generated and then interpreted by classical sorption models. The sorption behavior of water and its relationship with pore structure, organic/inorganic composition, and temperature (278–333 K) were explored using organic geochemistry, mineralogy, and gas physical sorption. Brunauer-Emmett-Teller theory functions well for these isotherms but generates ambiguous model parameters, suggesting that multilayer sorption concept is not suitable for water sorption. Dent model distinguishes between primary and secondary sorption, and the resulting specific surface area (ADent(H2O)) is not comparable to the nitrogen-determined specific surface area (ABET(N2)). However, ADent(H2O)/ABET(N2) linearly decreases with increasing ABET(N2), and water saturation is negatively correlated with total pore volume. These observations collectively support the surface-chemistry-controlled clustering mechanism for water sorption. Clay minerals dominate water sorption at low relative pressure because they provide more hydrophilic sorption sites for water cluster formation and growth. Nevertheless, organic matter becomes increasingly important with increasing relative pressure, primarily because a specific-sized organic pore has higher filling pressure than the same-sized clay pore resulting in more pronounced condensation in organic pores at high relative pressure. The water desorption branch shifts to higher relative pressure with increasing temperature and thus, the hysteresis loop shrinks, indicating a mechanism of capillary evaporation similar to wetting fluid nitrogen. The water adsorption branch is insensitive to temperature change, reflecting a temperature-independent clustering mechanism between 278 K and 333 K. The enthalpy of adsorption of collected shale samples is smaller than that of lower-maturity shales but close to that of condensation of bulk water. Based on this finding, we argue that higher-maturity shales have weaker interaction with water, which gives rise to lower temperature sensitivity of water sorption. Therefore, in the future, detailed investigations should revolve around water sorption behavior and its response to temperature in shales with different thermal maturities.

We attempted to differentiate the effects of thermal chemical alteration (TCA) from thermochemical sulfate reduction (TSR) on formation and isomeric distribution of thiadiamondoids and diamondoids in oils and condensate from deeply buried Cambrian and Ordovician carbonate reservoirs in the Tarim Basin, China. Diamondoids and thiadiamondoids with 1–3 cages were detected in all the oils analyzed. Total thiadiamondoid concentrations reflect extent of TSR. Diamondoid concentrations and most of the diamondoid-based maturity proxies and the source rock lithology proxy increase with increasing extent of TSR, indicating that they are controlled by the extent of the TSR process (or reaction with H 2 S) to a greater degree than by TCA. TSR may have oxidized hydrocarbons to oxygenated species and finally to CO 2 and newly generated and concentrated diamondoids and organic sulfur compounds. The most extensive TSR-altered ZS1C condensate contains 3.2 wt% total dibenzothiophenes, 0.4 wt% thiadiamondoids and 5.9 wt% diamondoids together with higher polymantanes including tetramantanes and pentamantanes in association with polythiadiamondoids, including dithiaadamantanes, trithiaadamantanes and tetrathiaadamantanes. These polythiadiamondoids have been detected only from heavily TSR-altered petroleum in this study and North American samples and may be derived from the sulfurization of hydrocarbons, including diamondoids, under high temperature and highly reducing conditions during advanced stages of TSR. The polymantanes may have been generated from alkylation of lower-cage diamondoids and subsequent homologation, or from free radical reactions. This study indicates that TSR may have led to the generation and isomerization of thiadiamondoids and diamondoids, and thus diamondoid-based maturity and lithology proxies cannot be used to reflect maturity and lithology in the TSR active areas, and that the occurrence of polythiadiamondoids can be used to indicate heavy TSR alteration.

During thermochemical sulfate reduction (TSR), H2S generated by reactions between hydrocarbons and aqueous sulfate back-reacts with remaining oil-phase compounds forming new organosulfur compounds (OSCs) that have similar δ34S values to the original sulfate. Using Compound Specific Sulfur Isotope Analysis (CSSIA) of alkylthiaadamantanes (TAs), alkyldibenzothiophenes (DBTs), alkylbenzothiophenes (BTs) and alkylthiolanes (TLs), we have here attempted to differentiate OSCs due to primary generation and those due to TSR in oils from the Tarim Basin, China. These oils were generated from Cambrian source rocks and accumulated in Cambrian and Ordovician reservoirs. Based on compound specific sulfur isotope and carbon isotope data, TAs concentrations and DBT/phenanthrene ratios, the oils fall into four groups, reflecting different extents of source rock signal, alteration by TSR, mixing events, and secondary generation of H2S. Thermally stable TAs, that were produced following TSR, rapidly dominate kerogen-derived TAs at low to moderate degrees of TSR. Less thermally stable TLs and BTs were created as soon as TSR commenced, rapidly adopted TSR-δ34S values, but they do not survive at high concentrations unless TSR is advanced and ongoing. The presence of TLs and BTs shows that TSR is still active. Secondary DBTs were produced in significant amounts, sufficient to dominate kerogen-derived DBTs, only when TSR was at an advanced extent. The difference in sulfur isotopes between (i) TLs and DBTs and (ii) BTs and DBTs and (iii) TAs and DBTs, represents the extent of TSR while the presence of TAs at greater than 20 μg/g represents the occurrence of TSR. The output of this study shows that compound specific sulfur isotopes of different organosulfur compounds, with different thermal stabilities and formation pathways, not only differentiate between oils of TSR and non-TSR origin, but can also reveal information about relative timing of secondary charge events and migration pathways.

Contents and types of organic nitrogen compounds (ONCs) in crude oil can critically affect the quality and the economic viability of oil products. In this article, anhydrous thermal cracking of carbazole was carried out using an autoclave at 425–525 °C, and heating times ranging from 187.5 to 237.5 h. The pyrolysis products were qualitatively and quantitatively characterized by gas chromatograph- thermal conductivity detector-flame ionization detector, gas chromatography–mass spectrometry and elemental analyzer. Reaction mechanism and kinetics were investigated on the basis of the experimental data. The results show that primary reaction products are aromatic hydrocarbons, N-containing compounds as well as CH 4 and H 2 ; whereas NH 3 , HCN and C 2 H 6 are minor products. At elevated temperatures degradation of carbazole undergoes simultaneously decomposition and condensation, involving cracking of C N bonds and C C bonds and forming of polycarbazole. Carbazole pyrolysis was demonstrated 0.8-order, and associated Arrhenius parameters of [ E (KJ/mol), A (s −1 )] = [321.628, 1.832 × 10 17 ] were determined. In comparison with dibenzothiophene, thermal stability of carbazole seems to be more unstable during thermal processing of residual oil. The present study may further improve our understanding of the evolution of complex ONCs in heavy oil refining.

We established a method based on a luminescence system driven by NADH conversion to quantitatively detect ethanol in alcoholic beverages. NADH produced by an ADH-catalyzed enzymatic reaction was used as an indicator to directly quantify luminescence in vitro. A strong linear relationship (R2 = 0.9942) was observed between the luminescence intensity and ethanol concentration over a range of 0.002–0.1 mol L−1, providing a detection limit of 1.43 × 10−4 mol L−1 for ethanol. This system has advantages such as rapid detection, high specificity, and repeatability in operation; therefore, it could be an advantageous alternative method for accurate quantification of ethanol content in beer, and may be suitable for other applications in the food industry.

In order to make a better understanding of the formation and evolution process of nanopores in organic-rich shales with increasing thermal maturity, an early mature oil shale from the Nenjiang Formation in Changling Depression of Songliao Basin was pyrolyzed with the presence of brine water in a closed system. The measurements of TOC, XRD, N2 adsorption were conducted on the initial and pyrolyzed samples. The results show that the development of nanoporosity within pyrolyzed shales can be divided into three phases with thermal maturity increasing: the intensive increase (Ro=0.61-2.09%), slight decrease (Ro=2.09-2.47%) and slight increase (Ro=2.47-4.01%). The significant occurrence of nanopores was associated closely with intensive hydrocarbon generation and expulsion at the mature to high mature stages, liquid hydrocarbons filling into the nanopores restricts their developments. The formation of pyrobitumen by oil secondary cracking at the early over mature stage decrease the occurrence of micropores and macropores, and hence reducing the pore volumes. The secondary phase of nanopores formation is at the late over mature stage, which is attributed to the mineral transformation and limited capability of hydrocarbon generation and expulsion. This study should be helpful in evaluating shale oil and gas resources in nature.

The natural evaporation of a condensate from the Tarim Basin in northwest China was conducted at room temperature to investigate the stable carbon isotopic fractionation of individual light hydrocarbons (LHs) in the C 6 –C 8 range. Our results show that individual LHs in this range in liquid residuals are progressively enriched in 13 C, indicating the preferential evaporation of 12 C containing compounds from the crude oil. When evaporative losses of individual LHs in the C 6 –C 8 range are δ 13 C final–initial δ 13 C final–initial of individual LHs in the C 6 –C 8 range >1‰ mainly occurs when the evaporative losses are >70%, but the magnitudes of stable carbon isotopic fractionation strongly depend on compound classes. Compared to the straight chain and branched alkanes and the monoaromatic hydrocarbons, there is almost no stable carbon isotopic fractionation observed for cycloalkanes in the C 6 –C 8 range. Using the Rayleigh model, stable carbon isotopic fractionation of individual LHs in the C 6 –C 8 range during natural evaporation is described and the stable carbon isotope fractionation factors ( α ) are 0.998976 for n -hexane, 0.998991 for n -heptane, 0.999426 for n -octane, 0.999138 for 3-methylhexane, 0.999401 for methylcyclohexane and 0.998518 for toluene. Correspondingly, the stable carbon isotope enrichment factors ( e ) are −1.024 for n -hexane, −1.009 for n -heptane, −0.574 for n -octane, −0.862 for 3-methylhexane, −0.599 for methylcyclohexane and −1.482 for toluene. Both α and e values clearly show a progressive enrichment in 13 C in the residual liquids during natural evaporation in a crude oil system (what is referred to as “normal isotope fractionation”), rather than an enrichment in 13 C in the vapor phase as reported by previous studies (what is referred to as “inverse isotope fractionation”). The intermolecular binding energies due to the van der Waals attraction forces in crude oil likely plays an important role on the diffusion velocity and the escape of 13 C containing LHs from the system, thereafter exerting a significant influence on stable carbon isotope fractionation, which is controlled by a kinetic isotopic effect. Since we cannot be certain of the exact amount of LHs that evaporated for one given crude oil from the subsurface to the laboratory, the results presented here strongly suggest that caution must be taken in the application of stable carbon isotopic composition of individual LHs in petroleum geochemistry and in environmental studies associated with oil pollution. However, δ 13 C values of cycloalkanes in the C 6 –C 8 range can still be used in confidence to decipher oil generation, migration, accumulation and secondary alteration in the subsurface of sedimentary basins and to address oil pollution issues.

This discussion reevaluates the data provided by Burruss and Laughrey (2010) (Carbon and hydrogen isotopic reversals in deep basin gas: Evidence for limits to the stability of hydrocarbons. Organic Geochemistry 41, 1285–1296). It indicates that gas diffusive migration plays an important role in regulating the isotopic reversals in samples from the Silurian and Ordovician formations in the Appalachian Basin. Carbon and hydrogen isotopic reversals in deep basin gas cannot be attributed to the stability of hydrocarbons in shale-gas and tight-sand-gas accumulations, if gas diffusive migration in the subsurface is not considered.

Experimental studies of the effects of thermochemical sulfate reduction (TSR) on light hydrocarbons were conducted in sealed gold tubes for 72 h at 400 °C and 50 MPa. A variety of pyrolysis experiments were carried out, including anhydrous, hydrous without MgSO4 (hydrous experiments) and hydrous with MgSO4 (TSR experiments). Common reservoir minerals including montmorillonite, illite, calcite and quartz were added to various experiments. Measurements of the quantities of n-C9+ normal alkanes (high molecular weight, HMW), n-C6–8 normal alkanes (low molecular weight, LMW), C7–8 isoalkanes, C6–7 cycloalkanes and C6–9 monoaromatics and compound specific carbon isotope analyses were made. The results indicate that TSR decreases hydrocarbon thermal stability significantly as indicated by chemically lower concentrations and isotopically heavier LMW saturated hydrocarbons in the TSR experiments compared to the hydrous and anhydrous experiments. In the LMW saturated hydrocarbon fraction, cycloalkanes tend to be more resistant to TSR than n-alkanes and isoalkanes. TSR promotes aromatization reactions and favors the generation of monoaromatics, resulting in higher chemical concentrations and isotopically equivalent compositions of monoaromatics in the anhydrous, hydrous and TSR experiments. This indicates that LMW monoaromatics are thermally stable during the pyrolysis experiments. Acid rather than basic catalyzed ionic reactions probably play a major role in TSR. This is suggested by the promotion effects of acid-clay minerals including illite and particularly montmorillonite. The basic mineral calcite retards the destruction of n-C9+ normal alkanes within the TSR experiments. Furthermore, clay minerals have a minor influence on the generation of LMW monoaromatics and play a negative role in regulating the concentrations of LMW saturated hydrocarbons; calcite does not favor the generation of LMW monoaromatics and plays a positive role in controlling the concentrations of LMW saturates relative to clay minerals. Quartz has a negligible role in the TSR experiments. Due to their differential responses to TSR, LMW hydrocarbon parameters, such as Schaefer [Schaefer, R.G., Littke, R., 1988. Maturity-related compositional changes in the low-molecular-weight hydrocarbon fraction of Toarcian Shale. Organic Geochemistry 13, 887–892], Thompson [Thompson, K.F.M., 1988. Gas-condensate migration and oil fractionation in deltaic systems. Marine and Petroleum Geology 5, 237–246], Halpern [Halpern, H., 1995. Development and application of light-hydrocarbon-based star diagrams. American Association of Petroleum Geologists Bulletin 79, 801–815] and Mango [Mango, F.D., 1997. The light hydrocarbons in petroleum: a critical review. Organic Geochemistry 26, 417–440] parameters and stable carbon isotopic compositions of individual LMW saturated hydrocarbons in TSR affected oils should be used with caution. In addition, water promotes thermal cracking of n-C9+ normal alkanes and favors the generation of LMW cycloalkanes and monoaromatics. The result is lower concentrations of n-C9+ HMW normal alkanes and higher concentrations of LMW cycloalkanes and monoaromatics in hydrous experiments relative to anhydrous experiments with or without minerals. This investigation provides a better understanding of the effects of TSR on LMW hydrocarbons and the influence of reservoir minerals on TSR in natural systems. The paper shows how LMW hydrocarbon indicators in TSR altered oils improve understanding of the processes of hydrocarbon generation, migration and secondary alteration in subsurface petroleum reservoirs.

Large amounts of data regarding the influence of temperature and pressure on the thermal stability of crude oil have been published; however, the role of reservoir mediums has received little attention. Experiments involving oil cracking in the presence of montmorillonite, illite, calcite, quartz and water were conducted in closed gold tubes to investigate the effects of these reservoir mediums on oil destruction. This was done by screening variations in the chemical and stable carbon isotopic components of nC10+ and gasoline-range hydrocarbons (nC8−) present in various systems. Results indicated that reservoir mediums have an active role in oil cracking under experimental conditions. The concentrations of nC10+ in the cracked residues progressively decreased in systems containing oil+water+illite, oil+water+montmorillonite, oil+water, oil+water+quartz and oil+water+calcite. In comparison with the system containing oil+water, our results indicated a retardation effect for oil cracking in systems in the presence of illite and montmorillonite, and an acceleration effect on oil destruction in systems in the presence of calcite and quartz. nC10+ became increasingly depleted in 13C in systems with oil+water+illite, oil+water+calcite, oil+water+montmorillonite, oil+water+ quartz and oil+water. No obvious correlation was observed between concentrations and stable carbon isotopic components of nC6-nC8 and nC10+ in the individual systems. The discrepancies in chemical and stable carbon isotopic components of nC6-nC8 and nC10+ in the pyrolyzed residues highlighted the important role of reservoir mediums to control carbon-carbon cleavage of nC10+ and then the isomerization, cyclolization and aromatization reactions; as well as governing the occurrence and thermal destruction of nC6-nC8 under experimental conditions. This research may have critical implications in reconstructing chemical kinetic models for natural oil cracking.

The timing of petroleum generation, migration, and accumulation in the central Junggar Basin has been evaluated using basin modeling technology to decipher the processes of petroleum secondary migration and accumulation in the Jurassic carrier beds during the Yanshan and Himalayan orogenies. During the early Yanshan orogeny (J2–J3), crude oils, sourced mainly from the Permian source rocks, migrated laterally from depocenters to adjacent structural high points. During the late Yanshan orogeny (Cretaceous–Eocene), the hydrocarbon secondary migration pattern changed significantly. Specifically, in the Cretaceous, a large-scale regional second phase of generation and migration occurred in the western part of the central Junggar Basin; in the eastern part of the central Junggar Basin, crude oils emplaced in the depressions migrated mainly to the eastern uplifts. In the early Tertiary, oils in the source kitchens generally began migrating to the north and mixed with the Jurassic-generated hydrocarbons. During the Himalayan orogeny (Neogene–Quaternary), this migration was strengthened continually. The modeled results agree with migration-associated geochemical information of the Jurassic accumulations. Integration of the regional geological setting and some petroleum geology data suggest that the Jurassic tectonic high points and facies-change- and unconformity-associated subtle traps are of crucial importance for current oil exploration. Both overpressured bodies in the Triassic and Permian systems and volcanic rock reservoirs of the Carboniferous basement in the uplifts have important implications for future natural oil and gas exploration. This work should help reduce exploration risk in this region.

Carbonate cemented zones are normally adjacent to the top overpressured surface in the central Junggar Basin, NW China. Stable carbon and oxygen isotopic compositions and petrological investigations of carbonate cements in the carbonate cemented zones indicate that: (1) carbonate cements are composed dominantly of ferrocalcite, ferroan dolomite, and ankerite; (2) carbonate cements are formed under a high temperature circumstance in the subsurface, and organic fluid migration has an important effect on the formation of them; and (3) carbon and oxygen ions in the carbonate cements migrate from the underlying overpressured system. This suggests that the occurrence of carbonate cemented zones in this region results from multiple phases of organic fluid expulsion out of the overpressure compartment through geological time. This study provides a plausible mechanism of the formation of carbonate cemented zones adjacent to the top overpressured surface in the clastic sedimentary basins, and has an important implication for understanding the internal correlation between the formation of carbonate cemented zones adjacent to top overpressured surface and geofluids expulsion out of overpressured system.

Fine control of Optical Thin Film Stress is critical to develop an expected profile parameters of large aperture coated optics. In our latest effort, the evolution of stress and force per unit width of multilayer thin film formulas, (H2L) 6 , (H2L) 5 H and (HL) 7 , consisted of HfO 2 and SiO 2 were researched. The stresses of SiO 2 single layers deposited on the HfO 2 were small than those grew on glass and get smaller as the multilayer thin film deposited. While the stresses of HfO 2 films deposited on the SiO 2 were positive correlation with the stress of SiO 2 .