An Integrated Optimization Method for CO_(2) Pre-Injection during Hydraulic Fracturing in Heavy Oil Reservoirs

CO_(2) pre-injection during hydraulic fracturing is an important method for the development of medium to deep heavy oil reservoirs.It reduces the interfacial tension and viscosity of crude oil,enhances its flowability,maintains reservoir pressure,and increases reservoir drainage capacity.Taking the Badaowan Formation as an example,in this study a detailed three-dimensional geomechanical model based on static data from well logging interpretations is elaborated,which can take into account both vertical and horizontal geological variations and mechanical characteristics.A comprehensive analysis of the impact of key construction parameters on Pre-CO_(2) based fracturing(such as cluster spacing and injection volume),is therefore conducted.Thereafter,using optimized construction parameters,a non-structured grid for dynamic development prediction is introduced,and the capacity variations of different production scenarios are assessed.On the basis of the simulation results,reasonable fracturing parameters are finally determined,including cluster spacing,fracturing fluid volume,proppant concentration,and well spacing.

High-efficiency Agrobacterium-mediated transformation of chrysanthemum via vacuum infiltration of internode

Leaf disc transformation is one of the traditional methods that are now widely used in chrysanthemum with highly economical and ornamental value in world flower production,but it depends on plant genotypes and is time consuming and complicated.In addition,the transformation success rate of this method is low,generally ranging from 0.1%to 6.25%.Therefore,a highly efficient transformation system is needed.In this study,we are the first to establish a high-efficient chrysanthemum Agrobacterium-mediated transformation system via vacuum infiltration.Chrysanthemum stem internode explants were used as research material and CmLEC1 was used as a reporter gene.After approximately 3 months of culture and selection,the positive transgenic plants were obtained.Additionally,the positive probability was about 42%.The transformation efficiency was up to 37.7%,and if the escapes were removed,it was 16%.Furthermore,stable expression of CmLEC1 in transgenic'Yuhualuoying'was confirmed by qRT-PCR analysis.These results suggest that this genetic transformation system via vacuum infiltration of chrysanthemum stem internode is highly efficient and convenient,and much better than traditional leaf disc transformation,and it will play an important role in chrysanthemum transformation and functional genetics research.

Structural superlubricity at homogenous interface of pentagraphene

Two-dimensional(2D)van der Waals layered materials have been widely used as lubricant.Penta-graphene(PG),a 2D carbon allotrope exclusively composed of irregular carbon pentagons has recently been predicted to have superlubricating property.In the present study,by combining the molecular dynamics simulation and first-principles calculations,we investigated the frictional property of PG in both commensurate and incommensurate contacts.Our calculations show the ultra-low friction at the interface of relatively rotated bilayer PG with twist angles of more than 10°away from the commensurate configuration.Meanwhile,our calculations demonstrate the isotropy of the ultra-low friction at the interface of incommensurate contact,in contrast to the anisotropic of the commensurate contacting interface.Additionally,the evolution of friction force and the fluctuation of potential energy along sliding path correlate closely with the interface’s structure.The energetics and charge density explain the difference between the friction at the interfaces of the commensurate and incommensurate contacts.Not only that,we found the correlation between the intrinsic structural feature and interlayer binding energy.Importantly,our findings on the retainment of the ultra-low friction under work conditions indicates that the superlubricating state of PG has good practical adaptability.

Simulation design and optimization of reactors for carbon dioxide mineralization

To achieve a synergistic solution for both sustainable waste management and permanent CO_(2) sequestration,CO_(2) mineralization via fly ash particles is an option.Based on computational fluid dynamics,two specialized reactors for fly ash mineralization were designed.The reactor designs were strategically tailored to optimize the interactions between fly ash particles and flue gas within the reactor chamber while concurrently facilitating efficient post-reaction-phase separation.The impinging-type inlet configuration dramatically enhanced the interfacial interaction between the fly ash particles and the gaseous mixture,predominantly composed of CO_(2) and steam.This design modality lengthens the particle residency and reaction times,substantially augmenting the mineralization efficiency.A rigorous investigation of three operational parameters,that is,flue gas velocity,carrier gas velocity,and particle velocity,revealed their influential roles in gas-particle contact kinetics.Through a computational investigation,it can be ascertained that the optimal velocity regime for the flue gas was between 20 and 25 m⋅s1.Concurrently,the carrier gas velocity should be confined to the range of 9-15 m⋅s1.Operating within these finely tuned parameters engenders a marked enhancement in reactor performance,thereby providing a robust theoretical basis for operational efficacy.Overall,a judicious reactor design was integrated with data-driven parameter optimization.

Molecular simulation on carbon dioxide capture performance for carbons doped with various elements

Among the different types of CO_(2)capture technologies for post-combustion,sorption CO_(2)capture technology with carbon-based sorbents have been extensively explored with the purpose of enhancing their sorption perfor-mance by doping hetero elements due to the rapid reaction kinetics and low costs.Herein,sorption capacity and selectivity for CO_(2)and N 2 on carbon-based sorbents doped with elements such as nitrogen,sulfur,phosphorus,and boron,are evaluated and compared using the grand canonical Monte Carlo(GCMC)method,the universal force field(UFF),and transferable potentials for phase equilibria(TraPPE).The sorption capacities of N-doped porous carbons(PCs)at 50℃were 76.1%,70.7%,50.6%,and 35.7%higher than those of pure PCs,S-doped PCs,P-doped PCs,and B-doped PCs,respectively.Its sorption selectivity at 50℃was approximately 14.0,nearly twice that of pure PCs or other hetero-element-doped PCs.The N-doped PCs showed the largest sorption heat at 50℃among all the PCs,approximately 20.6 kJ·mol^(−1),which was 9.7%−25.5%higher than that of the pure PCs under post-combustion conditions.Additionally,with the product purity of 41.7 vol.%−75.9 vol.%for vacuum pressure swing sorption,and 53.4 vol.%−83.6 vol.%for temperature swing sorption,the latter is more suitable for post-combustion conditions than pressure-swing sorption.

藤仓赤霉菌赤霉素生物合成及代谢调控研究进展

赤霉素是最重要的植物生长调节剂之一,在农业生产中得到越来越广泛的应用,具有广阔的市场前景,但其工业化的高生产成本严重制约着它的广泛应用。近年来,利用生物技术提升赤霉素产量日益成为研究热点。赤霉素生物合成是多种酶协同作用的过程,阐明赤霉素的生物合成机制,利用代谢工程策略调控代谢流量,对提高赤霉素产量至关重要。文中综述了当前藤仓赤霉菌赤霉素生物合成途径、关键酶、环境因素、代谢流调控等方面的研究进展,在代谢调控方面进行了展望,以期为实现赤霉素稳产高产提供思路。

Sorption of triclosan on electrospun fibrous membranes: Effects of pH and dissolved organic matter

Three hydrophobic and polyporous electrospun fibrous membranes(EFMs)were prepared by electrospinning methoxy polyethylene glycol-poly(lactide-co-glycolide)(MPEG-PLGA),poly(D,L-lactide-co-glycolide)(PLGA)and poly(D,L-lactide)(PDLLA).The effects of pH and dissolved organic matter(DOM)on triclosan(TCS)sorption by EFMs in aqueous solution were investigated.The results indicated that hydrogen bonding,hydrophobic and π-π bonding interactions led to fast adsorption,which governed the adsorption rates of TCS onto EFMs.The maximum sorption capacities of MPEG-PLGA,PLGA and PDLLA reached 130,93 and 99 mg g^-1,respectively,which were in positive correlation with their pore volumes and influenced by pore filling processes.The solution pH could significantly influence the TCS sorption by EFMs.In acid condition,protonated TCS facilitated their sorption onto EFMs.No obvious sorption was observed in alkaline condition due to repulsive forces between negatively charged EFMs and deprotonated TCS(pKa=7.9).The presence of DOM inhibited TCS sorption onto EFMs due to competitive adsorption.The results could be due to the occupation of the adsorption sites and the blockage of the pore entrance by DOM.