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Spontaneous imbibition is one of the important means to enhance oil recovery in low permeability reservoirs, and it has good field application effects. Through the interfacial tension (IFT), contact angle (CA), and adsorption experiments, the effects of SDBS surfactant on IFT and reservoir wettability were studied, and the adsorption rule of SDBS at the mineral surface was obtained. On this basis, the imbibition recovery and mechanism of cores with different permeability are studied. The study showed that in low permeability reservoir, gravity and capillary force are the main controlling factors of imbibition. In the early stage, gravity determines the recovery, because the imbibition rate is 2.75 times that dominated by capillary force. The capillary force can continue to produce oil in small pores, and the imbibition time is twice that of gravity, which determines the recovery in the late imbibition stage. Therefore, the synergistic effect of gravity and capillary force can optimize the imbibition recovery, in low permeability reservoirs. When the concentration of SDBS solution is CMC (0.1%), due to the mineral interface adsorbs, the capillary force decreases by 10.76%, and the adhesion work increases by 3.42 times, resulting in a decrease in the imbibition recovery. The imbibition driving force is different for different reservoir properties, which can be adjusted by adding a surfactant to change IFT and CA.

A one-dimensional biophysical model was developed to simulate upper ocean dynamics and seasonal nutrient (N, P, Si) export from the euphotic zone to the depths in the Southern Ocean. Simulations were made in the Subantarctic Zone (SAZ) and the Polar Frontal Zone (PFZ). The physical part of model was forced with the heat fluxes, freshwater fluxes and wind stresses provided by the National Centers for Environmental Prediction. In both the SAZ and PFZ, the model was capable of reproducing the amplitude of the seasonal sea surface temperature (SST) and the seasonality of the mixed layer depth (MLD). The MLD was deepest in August-October (600 m in the SAZ, 160 m in the PFZ) and shallowest in January-Februry (20m in the SAZ, 35m in the PFZ). The shallower summer MLD in the SAZ was due to lower wind stress. However, the shallower winter MLD in the PFZ was due to strong stratification in the water below the mixed layer. The biological component of the model used incident light, temperature, nutrient availability and estimates of phytoplankton biomass from satellite data recorded by the Sea-viewing Wide Field-of-view Sensor to determine production. The model was tuned to reproduce the observed seasonal cycle of nutrients. A series of sensitivity studies, taking into account uncertainties in both physical fields and biological formulations, led to several robust conclusions. The simulated annual export production was significantly higher in the PFZ (~65 mol P m\\(^{-2}\\)) than in the SAZ (~55 mol P m\\(^{-2}\\)) despite the PFZ having lower seasonal nutrient depletion in the euphotic zone. The higher export production in the PFZ was accomplished by having larger resupply of phosphate to the upper ocean during the September to March period (27 ‚ÄövÑvÆ 37 mol P m\\(^{-2}\\)) than in the SAZ (8 ‚ÄövÑvÆ 15 mol P m\\(^{-2}\\)). In the PFZ, it was assumed that nutrient utilization ratio followed the Redfield ratio in the non-diatoms and the NIP/Si utilization ratios were determined in the diatoms in a steady state ocean.-The estimated annual export production is ~65 mmol P m\\(^{-2}\\), ~820 mmol N m\\(^{-2}\\) and 1826 mmol Si M\\(^{-2}\\) in the euphotic zone for phosphate, nitrate and silicate respectively. The diatoms contribute 85% and 80% of the annual phosphate and nitrate export production. In the euphotic zone, the annual N/P utilization ratio is 11.5 ‚ÄövÑvÆ 12.9 in the diatoms and 12.1 ‚ÄövÑvÆ 13.6 in the community. The seasonal Si/N utilization ratio is 3 ‚ÄövÑvÆ 6 in the diatoms and 1 ‚ÄövÑvÆ 4 in the community, with the lowest found in the late summer. The annual Si/N utilization ratio is 2.5 ‚ÄövÑvÆ 3 in the diatoms and 2 ‚ÄövÑvÆ 2.5 in the community. The low NIP depletion ratio is associated with the preferential recycling of phosphate below the euphotic zone, the low N/P ratio in the labile dissolved organic material in the euphotic zone and the low N/P utilization ratio in the diatoms. The low N/P and high Si/N utilization ratio reflect the low iron availability in the PFZ waters.

Background Mei (Prunus mume) is the only woody plant in the genus Prunus with a floral fragrance, but the underlying mechanisms of aroma compound biosynthesis are unclear despite being a matter of considerable interest. Results The volatile contents of the petals of two cultivars with significantly different aromas, Prunus mume ‘Xiao Lve’ and Prunus mume ‘Xiangxue Gongfen’, were characterised by GC-MS at different flowering periods, and a total of 44 volatile compounds were detected. Among these, the main substances forming the typical aroma of P. mume were identified as eugenol, cinnamyl acetate, hexyl acetate and benzyl acetate, with variations in their relative concentrations leading to sensory differences in the aroma of the two cultivars. We compiled a transcriptome database at key stages of floral fragrance formation in the two cultivars and used it in combination with differential analysis of floral volatiles to construct a regulatory network for the biosynthesis of key aroma compounds. The results indicated that PmPAL enzymes and PmMYB4 transcription factors play important roles in regulating the accumulation of key biosynthetic precursors to these compounds. Cytochrome P450s and short-chain dehydrogenases/reductases might also influence the biosynthesis of benzyl acetate by regulating production of key precursors such as benzaldehyde and benzyl alcohol. Furthermore, by analogy to genes with verified functions in Arabidopsis, we predicted that three PmCAD genes, two 4CL genes, three CCR genes and two IGS genes all make important contributions to the synthesis of cinnamyl acetate and eugenol in P. mume. This analysis also suggested that the downstream genes PmBGLU18-like, PmUGT71A16 and PmUGT73C6 participate in regulation of the matrix-bound and volatile states of P. mume aroma compounds. Conclusions These findings present potential new anchor points for further exploration of floral aroma compound biosynthesis pathways in P. mume, and provide new insights into aroma induction and regulation mechanisms in woody plants.

The water-in-aging crude oil (WACO) emulsions treatment is an urgent problem in the offshore platform because of the low demulsification efficiency of conventional demulsifier. To resolve this problem, a new kind of tannic acid phenol-amine (TAPA) polyether with multiple branches, and aromatic rings is prepared in this article. This synthetic route is expected to avoid the side reactions during the synthesis of commercial phenol-amine resin. Benefit from this structure, the demulsification efficiency reaches 91.7% within 90 min in laboratory test and 97.9% within 45 min on offshore platform measurement toward WACO emulsions. Demulsification mechanism is systematically investigated by the measurements of hydrophile-lipophile balance (HLB) value, relative solubility number (RSN) value, dosage, interfacial activity and stability analysis. To have a direct insight into demulsification, the variation of water droplets in demulsification is observed. The effect of concentration and organic salts on cloud point are discussed. The demulsification effectiveness of TAPA demulsifier is mainly ascribed to the high interfacial activity, hyperbranched structure, multiple aromatic rings and suitable HLB value. These results indicate that TAPA could be an effective demulsifier in WACO emulsions breaking.

Additional file 1: Fig. S1. Current velocity in 1–8th August (a, d), 11–13th August (b, e), and 14–21st August (c, f) for non-typhoon years (top panel) and 2019 (lower panel) in the Yellow-Bohai Sea. Fig. S2. Ekman Pump velocity in 1–8th August (a, d), 11–13th August (b, e) and 14–21st August (c, f) for non-typhoon years (top panel) and 2019 (lower panel) in the Yellow-Bohai Sea. Fig. S3. Sea Surface Temperature (SST) in 1–8th August (a, d), 11–13th August (b, e) and 14–21st August (c, f) for non-typhoon years (top panel) and 2019 (lower panel) in the Yellow-Bohai Sea. Fig. S4. Sea surface salinity during 1–8th August (a), 11–13th August (b) and 14–21st August (c) for 2019 as well as the difference (d) between the first and last period in the Yellow-Bohai Sea. Fig. S5. Difference of euphotic depth between 1–8th and 14–21st August in 2019 in the Yellow-Bohai Sea.

Walnut shell filter materials has strong adsorption and contaminants interception ability, anti-oil immersion, high hardness, good wear resistance and stable chemical properties, its surface was easily polluted by the absorbed crude oil in oily sewage to reduce its filtering and backwashing effect. The surface modification of the walnut shell was the introduction of hydrophilic groups to enhance its hydrophilic oleophobic property; Used different ratio of sulfite to boil the walnut shell at a certain temperature to make a modification on the hydrophilicity of walnut shell surface, the modified filter materials with varying degree of surface modification was obtained. Measured the contact angle between walnut shell and water, the wetting performance was significantly improved, the contact angle was decreased from 95° to 36.75°, the surface properties were changed from lipophilicity to hydrophily. the micropores of surface become smaller, and it was conducive to the accumulation of emulsified oil beads; After filtration treatment of oily wastewater containing polymer, filter oil removal rate was over 78%, the oil removal rate of the modified filter materials was increased by 25% than that of the unmodified filter materials, and oil content in the filtered sewage was below 45 mg/L, the backwashing oil removal effect of modified filter materials increased from 17% to 87%, intercepted oil in the before process of filtration was more easier removed in the after process of backwashing to make the filtering performance regeneration of walnut shell filter materials. In the case of filtration treatment on the same amount of oily sewage its lifetime could be extended more than twice.

The pyrolytic conversion of vinyl-terminated poly[hydridomethylsiloxane-co-vinylmethylsiloxane] (PSO) into SiOC ceramic at various heating rates has been investigated by thermogravimetry coupled with mass spectrometry. Kinetic analysis on pyrolysis process of PSO has been conducted by peak-fitting method. The results show that all the experimental derivative thermogravimetric curves recorded at five different heating rates can be best fitted by four Gaussian functions. The activation energy for each peak was determined by an isoconversional method, and kinetic models for Peaks 1 and 2 were investigated on the basis of Master plots. The results show that Peak 1 was governed by R2-type mechanisms, while Peak 2 followed diffusion-type transport mechanisms. Plausible chemical pathways for the evolved gases within these peaks are also discussed. The release of a large amount of carbon-containing species was identified in the temperature ranges corresponding to Peak 2 and 4, which are associated with the mineralization and ceramization steps, respectively. The transition from mineralization to ceramization process occurs in the region of Peak 3, and is accompanied by the evolution of H2.

Existent nucleic acid isothermal detection techniques for clinical diseases are difficult to promote greatly due to limitations in such aspects as methodology, costs of detection, amplification efficiency and conditions for operation. There is therefore an urgent need for a new isothermal amplification method with the characteristics of high accuracy, easy operation, short time of detection and low costs. We have devised a new method of nucleic acid isothermal amplification using Bst DNA polymerase under isothermal conditions (60–65°C). We call this method of amplification by shortening the distance between forward and reverse primers for nucleic acid isothermal amplification SDAMP. The results demonstrated that this technique is highly sensitive, specific and has short reaction times (40–60 min). Results of sequencing show that the products of SDAMP amplification are mainly polymers formed by series connection of monomers formed through linkage of forward primer and complementary sequences in reverse primer via a few bases. The method is different from current methods of nucleic acid amplification. Our study shows, however, that it is a specific method of nucleic acid isothermal amplification depending on interactions between primers and DNA template.

6 pages, 3 figures, 1 table, supporting information http://onlinelibrary.wiley.com/doi/10.1029/2008GL036568/suppinfo, El Niño-Southern Oscillation (ENSO) properties can be modulated by many factors; most previous studies have focused on physical aspects of the climate system in the tropical Pacific. Ocean biology-induced feedback (OBF) onto physics and bio-climate coupling have been the subject of much recent interest, revealing striking model dependence and even conflicting results. Current satellite data are able to resolve the space-time structure of oceanic signals both in biology and physics, providing an opportunity for quantifying their relationships. Here we use the biological signature from satellite ocean color data to estimate interannual variability of the attenuation depth of solar radiation (Hp), a field linking ocean biology and physics. We then apply a singular value decomposition (SVD) analysis to interannual Hp and sea surface temperature (SST) anomaly fields to derive an empirical Hp model which is incorporated in a hybrid coupled ocean-atmosphere model of the tropical Pacific to represent the OBF. It is shown that the OBF can have significant effects on ENSO behaviors, including its amplitude, oscillation periods and seasonal phase locking, This research is supported in part by a NSF grant (ATM-0727668) and NASA grants (NCC5374, NAG512246, NNX08AI74G, NNX08AI76G and NNX08AT50G). J. Ballabrera-Poy is supported by a Ramón y Cajal contract from the Spanish Ministry of Science and Innovation and D. Chen is supported by the National Natural Science Foundation of China under contract No 40730843 and the National Basic Research Program of China under contract No 2007CB816005

The application of plastic microfluidic chips can be extended with quartz capillaries connected at the end of their microchannels, e.g. UV absorption detection method can be carried out, which responds to almost 80% chemical compounds in detection. Experiment system for automatic microassembly was developed to carry out the task of joining capillaries to plastic microfluidic chips. Experiments were done with different viscosity of UV curing adhesives, dispensing time, dispensing pressure and curing time. Suitable process parameters were determined. Visual feedback is employed in the microassembly system. The automatic positioning of capillary with visual information is described. The problems met during assembly are discussed and solved

Despite of their success, the results of first-principles quantum mechanical calculations contain inherent numerical errors caused by various approximations. We propose here a neural-network algorithm to greatly reduce these inherent errors. As a demonstration, this combined quantum mechanical calculation and neural-network correction approach is applied to the evaluation of standard heat of formation $\DelH$ and standard Gibbs energy of formation $\DelG$ for 180 organic molecules at 298 K. A dramatic reduction of numerical errors is clearly shown with systematic deviations being eliminated. For examples, the root--mean--square deviation of the calculated $\DelH$ ($\DelG$) for the 180 molecules is reduced from 21.4 (22.3) kcal$\cdotp$mol$^{-1}$ to 3.1 (3.3) kcal$\cdotp$mol$^{-1}$ for B3LYP/6-311+G({\it d,p}) and from 12.0 (12.9) kcal$\cdotp$mol$^{-1}$ to 3.3 (3.4) kcal$\cdotp$mol$^{-1}$ for B3LYP/6-311+G(3{\it df},2{\it p}) before and after the neural-network correction., Comment: 5 pages, 3 figures, REVTeX4 style, submitted to Phys.Rev.Letters

Around the world, peatland degradation and soil subsidence is occurring where these soils have been converted to agriculture. Since initial drainage in the mid-1800s, continuous farming of such soils in the California Sacramento-San Joaquin Delta (the Delta) has led to subsidence of up to 8 meters in places, primarily due to soil organic matter (SOM) oxidation and physical compaction. Rice (Oryza sativa) production has been proposed as an alternative cropping system to limit SOM oxidation. Preliminary research on these soils revealed high N uptake by rice in N fertilizer omission plots, which we hypothesized was the result of SOM oxidation releasing N. Testing this hypothesis, we developed a novel N budgeting approach to assess annual soil C and N loss based on plant N uptake and fallow season N mineralization. Through field experiments examining N dynamics during growing season and winter fallow periods, a complete annual N budget was developed. Soil C loss was calculated from SOM-N mineralization using the soil C:N ratio. Surface water and crop residue were negligible in the total N uptake budget (3 – 4 % combined). Shallow groundwater contributed 24 – 33 %, likely representing subsurface SOM-N mineralization. Assuming 6 and 25 kg N ha-1 from atmospheric deposition and biological N2 fixation, respectively, our results suggest 77 – 81 % of plant N uptake (129 – 149 kg N ha-1) was supplied by SOM mineralization. Considering a range of N uptake efficiency from 50 – 70 %, estimated net C loss ranged from 1149 – 2473 kg C ha-1. These findings suggest that rice systems, as currently managed, reduce the rate of C loss from organic delta soils relative to other agricultural practices.