Search

The organic‐rich shale of the seventh Oil Member (Chang 7 Member for short) of the Middle‐Late Triassic Yanchang Formation is extensively distributed in the southern margin of the Ordos Basin. Understanding the palaeoenvironmental conditions during the sedimentary period of the Chang 7 Member is crucial to exploring the main factors that control the enrichment of organic matter in high‐quality source rocks. In this study, lithofacies analysis was conducted, and samples were collected from the N36 well located in the southern part of the Ordos Basin. Subsequently, element geochemical analysis was performed to reconstruct the palaeoenvironment, and total organic carbon (TOC) tests were conducted to analyse the characteristics of organic matter enrichment. The findings indicate that the sedimentary period of the Chang 7 Member was characterized by a relatively warm and humid palaeo‐climate and a brackish water environment with oxygen‐poor or sub‐oxygen‐rich conditions, and a gradual decrease in palaeo‐water depth. The parent rock types were mainly felsic igneous rock and intermediate igneous rock, which provide limited nutritional elements for primary producers. The enrichment of organic matter in the Chang 7 Member is influenced by several factors, mainly including palaeo‐salinity, palaeo‐water depth, palaeo‐redox conditions, terrestrial inputs, and palaeo‐climate. The warm and humid palaeo‐climate, higher palaeo‐productivity, relatively higher palaeo‐salinity, lower terrigenous input, deeper palaeo‐water depth, and better preservation conditions are conducive to the development of high‐quality source rock in the Chang 7 Member. [ABSTRACT FROM AUTHOR]

A pH‐responsive amphiphilic surfactant stearic amide 3‐(N,N‐dimethylamino)propylamide (SAA) was synthesized and served as a thickener in aqueous solution to construct a switchable viscoelastic surfactant fluid (VES fluid). The structure of SAA was studied by 1H NMR, and the viscoelastic behavior of VES fluid was studied in detail by rheological measurements. The viscosity of this VES fluid can be switched reversibly from low to high immediately by adjusting system pH value. Even at high shear rate (170 s−1) and high temperature (90 °C), excellent viscoelastic behavior of this VES fluid can be observed, which is a key performance for fracturing applications. Meanwhile, the recycled VES fluid can still maintain good pH‐responsive behavior even after more than three cycles. These unique performances of this VES fluid not only enhanced our understanding of the transformation of wormlike micelles at high temperature, but also enriched a large potential of VES fracturing fluid in the development of oil and gas reservoirs. [ABSTRACT FROM AUTHOR]

A study was conducted to investigate the effects of oregano essential oil (EO) on growth performance, nutrients utilization, intestinal morphology, intestinal barrier‐related gene expression and antioxidant capability in meat ducks. A total of 360 1‐day‐old ducks were divided into three groups (12 replicates pens per diet of 10 ducks in each pen): negative control (no essential oil or antibiotic), positive control (antibiotic: 500 mg/kg aureomycin of diet) and oregano EO (100 mg/kg of diet). The experiment was carried out for 35 days. Ducks were given feed and water ad libitum. Ducks fed EO supplement showed similar body weight and feed to gain ratio to antibiotic fed ducks. EO supplementation significantly increased (p <.05) feed intake (day 1–35), jejunal villus height (VH) to crypt depth (CD) ratio, serum superoxide dismutase activities (SOD) and jejunal total antioxidant capacity (T‐AOC) of ducks compared to controls. Ducks fed diets supplemented with oregano EO also had decreased (p <.05) jejunal CD, serum and hepatic malondialdehyde (MDA) concentration, and the mRNA expression of jejunal zonula occludens‐3 (ZO‐3) and secretory immunoglobulin A (sIgA) genes in comparison to the control group. Compared to the antibiotic supplementation group, the mRNA expression of claudin1 (CLND1) and CLND2 significantly increased (p <.05), but the mRNA expression of ZO‐3 and mucin 2 markedly decreased (p <.05) in the jejunum of ducks in oregano EO supplementation group. These results suggest that oregano EO improves the antioxidant capacity and intestinal defence and structural measures and may aide in helping to maintain enteric health in production without growth‐promoting antibiotics. [ABSTRACT FROM AUTHOR]

Herein we show that by appending bulky β‐cyclodextrin (CD) groups onto sheet‐forming peptoids, we obtain cylindrical micelles that further assembly into membranes and intertwined ribbons on substrates in aqueous solution, depending on the choice of solution and substrate conditions. In situ atomic force microscopy (AFM) shows that micelle assembly occurs in two steps, starting with "precursor" particles that transform into worm‐like micelles, which extend and coalesce to form the higher order structures with a rate and a degree of cooperativity dependent on pH and Ca2+ concentration. After co‐assembly with hydrophobic 4‐(2‐hydroxyethylamino)‐7‐nitro‐2,1,3‐benzoxadiazole (NBD) donors that occupy the hydrophobic core, followed by exposure to hydrophilic Rhodamine B as acceptors that insert into cyclodextrin, the micelles exhibit highly efficient Förster resonance energy transfer efficiency in aqueous solution, thereby mimicking natural light harvesting systems. [ABSTRACT FROM AUTHOR]

A novel gel phase was constructed in a catanionic surfactant system with the compositions of 1-tetradecyl- 3-methylimidazolium chloride (CmimCl) and sodium dodecyl sulfate (SDS). The gel phases were studied through visual observations, differential scanning calorimetry (DSC), rheological measurements, and scanning electron microscopy (SEM). The visual observation and DSC confirmed the formation of gels and phase transitions from gel to sol. The dynamic rheological results showed the viscoelastic properties of gels. The SEM technique was used to further indicate the microstructure of gels. Finally, the formation mechanisms of gels are proposed based on the critical packing parameter. We expect to develop a new route to construct the gels. [ABSTRACT FROM AUTHOR]

A noncovalent bonding method was utilized for forming multiresponsive surface-active ionic liquids in mixed N-alkyl- N-methylpiperidinium bromide (CMDB) and potassium phthalic acid (PPA). Rheology, cryogenic-transmission electron microscopy, dynamic light scattering and nuclear magnetic resonance were used to investigate the aggregation property of surface-active ionic liquids in aqueous solution. The efficiency of the shielding effect in the form of hydrophobic effects and electrostatic attraction between PPA and the CMDB headgroup under diverse pH conditions is found to be the root cause of a shift in the aggregate's morphological transformation. In addition, the molecular motion of surfactant molecules becomes more active as the temperature increase provides the property of thermoresponsive to the surface-active ionic liquid system. [ABSTRACT FROM AUTHOR]