The reform and opening-up of China have greatly improved the scale and quality of doctoral education for women. However, female doctors still face the “leaky pipeline” and the “unbreakable glass ceiling” in their development of academic careers. In this study, gender differences are investigated in doctoral graduates’ career choices, the level of educational institutions they attend, and their scientific research productivity after joining the institution. We analyzed the administrative data and scientific research publication information from ten years of doctoral graduates at a top research university in China. Results suggest that compared to their male counterparts, female doctors are more likely to pursue an academic career upon graduation, but they are also more likely to be employed in lower-level institutions as well as to publish Chinese scientific studies with lower influence and poorer quality. Moreover, gender differences in academic disciplines are heterogeneous. While academic career development for doctors in natural sciences is not gender-biased, female doctors in social sciences face the most significant challenges, and these results persist even after controlling for their scientific publications during graduate school. In other words, gender differences in academic career development are likely to result from gender symbols rather than differences in academic ability.
This study explores how L1 and L2 Chinese speakers use world knowledge and classifier information to predict fine-grained referent features. In a visual-world-paradigm eye-tracking experiment, participants were presented with two visual objects that were denoted by the same noun in Chinese but matched different shape classifiers. Meanwhile, they heard sentences containing world knowledge triggering context and classifiers. The effect of world knowledge has been differentiated from word-level associations. Native speakers generated anticipations about the shape/state features of the referents at an early processing stage and quickly integrated linguistic information with world knowledge upon hearing the classifiers. In contrast, L2 speakers show delayed, reduced anticipation based on world knowledge and minimal use of classifier cues. The findings reveal different cue-weighting strategies in L1 and L2 processing. Specifically, L2 speakers whose first languages lack obligatory classifiers do not employ classifier cues in a timely manner, even though the semantic meanings of shape classifiers are accessible to them. No evidence supports over-reliance on world knowledge in L2 processing. This study contributes to the understanding of L2 real-time processing, particularly in L2 speakers’ utility of linguistic and non-linguistic information in anticipating fine-grained referent features.
The collapse of the former Soviet Union signaled failure of large-scale experiment in communitarian property. Privatization reform consequently was taken as the start point to transfer the planned economy to a market economy by the post socialist countries. This also occurred in economic transition countries such as China. However, in overcoming the tragedy of the commons privatization might create anticommons problems. Here we develop a nested common-private interface framework from the perspective of resource system and resource units and apply this framework to explain reforms of rangeland property in China and Kyrgyzstan. We confirmed that the root of the dilemma, either caused by commons or anticommons, can be attributed to the interface mismatch between individual elements and common elements. Trying to overcome the dilemma by changing property arrangements alone cannot eliminate the incentive mismatch caused by the common-private interface. Institutions aimed at alleviating the mismatch are accordingly required. Theoretically, this framework converts Ostrom's concept of commons into liberal commons that the members have options to exit, which is becoming increasingly common in the current global context of marketization. In the real world, this framework can serve to understand the property reform progress of transition countries, and may enlighten future property reforms.
Carbon dioxide (CO2) flooding holds immense potential for enhancing hydrocarbon recovery and facilitating geological carbon storage. Among CO2 flooding methods, miscible flooding demonstrates significantly higher production compared to immiscible flooding. However, in certain reservoirs, the high miscibility pressure presents a challenge for achieving miscibility under reservoir pressure conditions. Nonionic surfactants offer a solution by reducing the miscibility pressure in hydrocarbon-CO2 systems. In this study, eight nonionic surfactants were assessed, and two of the most effective surfactants were selected. These surfactants were combined to create a novel nonionic surfactant system aimed at lowering the miscibility pressure. The minimum miscibility pressure (MMP) of the hydrocarbon-CO2 system was measured using a slim-tube experiment, and a comparative analysis was conducted between the vanishing interfacial tension method (VIT) and the slim-tube method. Furthermore, the microscopic mechanism by which surfactants reduce the miscibility pressure was studied and analyzed. The findings indicate that the compound nonionic surfactant SF, with a total concentration of 1.0 wt% and a SMF to Span20 ratio of 1:1, reduces the miscibility pressure by 18.30%. The slim-tube data were processed to obtain a narrower range for MMP using criteria such as the crude oil recovery factor (ORF) and the break-over pressure (BOP). The maximum error between MMP measured by the VIT method and the slim-tube experiment is 5.86%, demonstrating the high accuracy of the VIT method in this study. The surfactant effectively reduces the miscibility pressure by decreasing the interfacial tension (IFT) between oil and gas, enhancing the CO2 extraction efficiency on intermediate hydrocarbons within the crude oil, and improving the solubility of CO2 in the crude oil. The findings of this study hold significant guidance for future investigations on the miscibility in the processes of geological CO2 utilization and storage.
The CO2 and Sodium Dodecyl Sulfate (SDS) assisted steam flooding technology was an effective approach addressed the persistent issues that have hindered the stable development of high-viscosity cold oil through steam injection. However, in the process of steam flow through porous media, the synergistic influence of the oil film adsorbed in near wellbore porous media, and the CO2-SDS on steam heat transfer has not been investigated. Steam heat transfer is the key factors affecting heavy oil recovery. The primary objective of this study was to research the effect of CO2-SDS on steam heat transfer and oil film stripping by designing experiments. The study results demonstrated that in the initial stage of displacement, the heat transfer resistance between the steam and the porous medium was increased by the oil film adsorbed in near wellbore area. In additional, the condensation mode of the steam was altered from bead condensing to film condensing by the composite thermal fluid flooding, preventing the steam heat dissipation near wellbore area and transferring more thermal to the long-distance area. At the later stage of displacement, the interfacial tension between oil-water and oil-gas was reduced by CO2-SDS, improving the fluidity of oil and providing the seepage channel for steam, and increasing the steam thermal sweep range. Compared to the sandpack experiment of steam flooding, the temperature at the output end of the sandpack model increased from 69.8 °C to 88.7 °C, indicating an expansion of the steam heat sweep range and successful long-distance heat transfer during composite thermal fluid flooding. In the process of composite thermal fluid flooding, the maximum displacement pressure difference increased from 2.28 MPa to 3.07 MPa, and the maximum oil recovery rate increased from 2.48 g/mL to 2.81 g/mL. The peak of the high production period was raised, resulting in a 40.97% to 51.86% increase in recovery rates.
ron/chromium hydroxide coprecipitation controls the fate and transport of toxic chromium (Cr) in many natural and engineered systems. Organic coatings on soil and engineered surfaces are ubiquitous; however, mechanistic controls of these organic coatings over Fe/Cr hydroxide coprecipitation are poorly understood. Here, Fe/Cr hydroxide coprecipitation was conducted on model organic coatings of humic acid (HA), sodium alginate (SA), and bovine serum albumin (BSA). The organics bonded with SiO2 through ligand exchange with carboxyl (–COOH), and the adsorbed amounts and pKa values of –COOH controlled surface charges of coatings. The adsorbed organic films also had different complexation capacities with Fe/Cr ions and Fe/Cr hydroxide particles, resulting in significant differences in both the amount (on HA > SA(–COOH) ≫ BSA(–NH2)) and composition (Cr/Fe molar ratio: on BSA(–NH2) ≫ HA > SA(–COOH)) of heterogeneous precipitates. Negatively charged –COOH attracted more Fe ions and oligomers of hydrolyzed Fe/Cr species and subsequently promoted heterogeneous precipitation of Fe/Cr hydroxide nanoparticles. Organic coatings containing –NH2 were positively charged at acidic pH because of the high pKa value of the functional group, limiting cation adsorption and formation of coprecipitates. Meanwhile, the higher local pH near the –NH2 coatings promoted the formation of Cr(OH)3. This study advances fundamental understanding of heterogeneous Fe/Cr hydroxide coprecipitation on organics, which is essential for successful Cr remediation and removal in both natural and engineered settings, as well as the synthesis of Cr-doped iron (oxy)hydroxides for material applications.