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Soil microorganisms can be altered by plant invasion into wetland ecosystems and comprise an important linkage between phosphorus (P) availability and soil carbon (C) chemistry; however, the intrinsic mechanisms of P and C transformation associated with microbial community and function are poorly understood in coastal wetland. In this study, we used a sequential fractionation method and 13C nuclear magnetic resonance (NMR) spectroscopy to capture the changes in soil P pools and C chemical composition with bare flats (BF), native Phragmites australis(PA), and invasive Spartina alterniflora(SA), respectively. The responses of the soil microbial community using phospholipid fatty acid (PLFA) profiling and function indicated by nine enzyme activities associated with C, nitrogen (N), and P cycles were also investigated. Compared to PA and BF, SA invasion significantly (P < 0.05) changed P pools and mainly increased the available P by 17.5 and 37.0%, respectively. The presence of the plants (SA and PA) significantly (P < 0.05) altered the soil C chemical composition mainly by affecting the aliphatic functional groups, resulting in a lower alkyl C/O-alkyl C ratio value. Compared to BF and SA, PA significantly (P < 0.05) increased arbuscular mycorrhizal fungi (AMF) abundance. Soil enzyme activity, especially for the P and C cycle enzymes, was also affected by plant species with the highest geometric mean enzyme and hydrolase activity for the PA zone. We also found that soil C compositions and P pools were associated with microbial community structure and enzyme activity, respectively. However, little interaction between C and P was found on either soil microbial composition or soil enzyme activity variation. Further, microbial community composition was tightly correlated with the soil P compared to soil C chemistry, while enzyme activity showed more response with soil C chemistry compared to soil P pool changes.

Conventional acid diversion agents cannot tolerate the high temperature and salinity of acidizing water-producing oil wells that contain bottom water and heterogeneous layers. Therefore, a water/oil (w/o) emulsion was proposed as an acid diversion agent to promote acidification. The selected emulsifier, oleic acid imidazoline, is a switchable emulsifier. Because this emulsifier reacts with acids to transform amines into ammonium, the emulsion rapidly demulsifies, and the emulsion acid diversion agent can use the spent acid flowback to remove plugging. Evaluation of the emulsion properties indicated that a 10 wt % emulsifier generated a stable emulsion at oil/water ratios from 1:9 to 4:6 at 90 °C. Viscosity was higher at lower oil/water ratios, and the emulsion with an oil/water ratio of 4:6, which had a low viscosity, was injected into the formation. During injection, the emulsion continued to emulsify in high-permeability channels, which increased the viscosity until the water layer was blocked. During experiments, single-tube and dual-tube models were designed to evaluate the injectivity and plugging selectivity of this emulsion. The results showed that the resistance factors exceeded 14 in the high-permeability cores when the emulsion was injected. The higher permeability ratio in parallel cores allowed a larger emulsion volume to enter the high-permeability cores. In experiments using parallel cores, the block rate of the high-permeability cores exceeded 92%, and that of the low-permeability cores was less than 12%. Finally, this emulsion was injected into two groups of parallel carbonate cores for acidification diversion tests. The results indicated that the permeability of the acidified low-permeability core was basically the same as that of the high-permeability core plugged by the emulsion. The findings of this study improve the understanding of the feasibility and advantages of using emulsions as acid diversion agents for high-temperature and high-salinity oil wells containing bottom water.

It is known that thermoelectric power generators (TEGs) can utilize geothermal resources and recycle waste heat. It is vital to improve the thermoelectric power generation efficiency to economically and efficiently use these thermal resources. In this paper, ANSYS was used to build a three-dimensional model of a very simple TEG with only one pair of p- and n-legs (1-PN-TEG) to find the optimal design. The thickness of the semiconductor elements, the cross-sectional area of p- and n-type semiconductor elements, the heat insulation material, the thickness of copper sheet, and other factors were analyzed to study their effects on the power output of 1-PN-TEG. The results show that the power of TEG increases first and then decreases with the thickness of p- and n-legs (H); the maximum power existed at a specific value of H. The power increases when the cross-sectional areas of p- and n-type semiconductor elements become more extensive, but the power per area decreases. Furthermore, the power increases with the volume of p- and n-type semiconductor elements and tends to be stabilized finally. This observation may be used to estimate how much thermoelectric material is required to generate a specific value of TEG power. The gaps between p- and n-type semiconductor elements were filled with different heat insulation materials. The heat insulation material with lower thermal conductivity had a greater power output. The thickness of the copper sheet, as a conductor between p- and n-type semiconductor elements, was also investigated. The maximum power value was reached when the thickness of the copper sheet was equal to about 1.0 mm. All of the results obtained in this paper might provide a theoretical basis for the configuration and design optimization of a thermoelectric generator, making more efficient use of geothermal resources and the waste heat.

Bio-optical imaging can noninvasively describe specific biochemical reaction events in small animals using endogenous or exogenous imaging reagents to label cells, proteins, or DNA. The fluorescence optical bio-imaging system excites the fluorescent group to a high energy state by excitation light and then generates emission light. However, many substances in the organism will also emit fluorescence after being excited by the excitation light, and the nonspecific fluorescence generated will affect the detection sensitivity. This paper designs and develops a set of high-level biosafety in vivo fluorescence imaging system for small animals suitable for virology research and proposes a target area extraction algorithm for fluorescence images. The fluorescence image target extraction algorithm first maps the nonlinear separation data in the low-dimensional space to the high-dimensional space. Then, based on the analysis of the characteristics of the fluorescent region, a method for discriminating the target fluorescent region based on the two-step entropy function is proposed, and the real target fluorescent region is obtained according to the set connected region. Based on the experiment of collecting and analyzing the in vivo fluorescent images of mice, it is verified that the proposed algorithm can automatically extract the target fluorescent region better than the classical linear model. It shows that the proposed algorithm is less affected by background fluorescence, and the estimated separated spectrum based on this method is closer to the real target spectrum.

The recirculation of gases in a sealed reactor system is a broadly useful method in catalytic and electrocatalytic studies. It is especially relevant when a reactant gas reacts slowly with respect to residence time in a catalytic reaction zone and when mass transport control through the reaction zone is necessary. This need is well illustrated in the field of electrocatalytic N2 reduction, where the need for recirculation of 15N2 has recently become more apparent. Herein, we describe the design, fabrication, use, and specifications of a lubricant-free, readily constructed recirculating pump fabricated entirely from glass and inert polymer (poly(ether ether ketone) (PEEK), poly(tetrafluoroethylene) (PTFE)) components. Using these glass and polymer components ensures chemical compatibility between the piston pump and a wide range of chemical environments, including strongly acidic and organic electrolytes often employed in studies of electrocatalytic N2 reduction. The lubricant-free nature of the pump and the presence of components made exclusively of glass and PEEK/PTFE mitigate contamination concerns associated with recirculating gases saturated with corrosive or reactive vapors for extended periods. The gas recirculating glass pump achieved a flow rate of >500 mL min-1 N2 against atmospheric pressure at 15 W peak power input and >100 mL min-1 N2 against a differential pressure of +6 in. H2O (∼15 mbar) at 10 W peak power input.

Efficient and highly stereoselective syntheses of (+)-proto-quercitol and (-)-gala-quercitol starting from the naturally abundant (-)-shikimic acid were described in this article. (-)-Shikimic acid was first converted to the key intermediate by eight steps in 53% yield. It was then converted to (+)-proto-quercitol by three steps in 78% yield and was also converted to (-)-gala-quercitol by five steps in 63% yield. In summary, (+)-proto-quercitol and (-)-gala-quercitol were synthesized from (-)-shikimic acid by 11 and 13 steps in 41 and 33% overall yields, respectively.