Mixed matrix membranes(MMMs)have demonstrated significant promise in energy-intensive gas separations by amalgamating the unique properties of fillers with the facile processability of polymers.However,achieving a sim...Mixed matrix membranes(MMMs)have demonstrated significant promise in energy-intensive gas separations by amalgamating the unique properties of fillers with the facile processability of polymers.However,achieving a simultaneous enhancement of permeability and selectivity remains a formidable challenge,due to the difficulty of achieving an optimal match between polymers and fillers.In this study,we incorporate a porous carbon-based zinc oxide composite(C@ZnO)into high-permeability polymers of intrinsic microporosity(PIMs)to fabricate MMMs.The dipole–dipole interaction between C@ZnO and PIMs ensures their exceptional compatibility,mitigating the formation of non-selective voids in the resulting MMMs.Concurrently,C@ZnO with abundant interconnected pores can provide additional low-resistance pathways for gas transport in MMMs.As a result,the CO_(2) permeability of the optimized C@ZnO/PIM-1 MMMs is elevated to 13,215 barrer,while the CO_(2)/N_(2) and CO_(2)/CH_(4) selectivity reached 21.5 and 14.4,respectively,substantially surpassing the 2008 Robeson upper bound.Additionally,molecular simulation results further corroborate that the augmented membrane gas selectivity is attributed to the superior CO_(2) affinity of C@ZnO.In summary,we believe that this work not only expands the application of MMMs for gas separation but also heralds a paradigm shift in the application of porous carbon materials.展开更多
Microporosity formed in the solidification process of Al alloys is detrimental to the alloy properties.A two-dimensional cellular automaton(CA)model was developed to simulate the microstructure and microporosity forma...Microporosity formed in the solidification process of Al alloys is detrimental to the alloy properties.A two-dimensional cellular automaton(CA)model was developed to simulate the microstructure and microporosity formation in Al-Cu alloys,considering variations in Cu content and solidification rate.The results indicate that the Cu content primarily influences the growth of microporosity.To validate the model,directional solidification experiments were conducted on Al-Cu alloys with varing Cu contents and withdrawal rates.The experimental results of dendrites and microporosity characteristics agree well with the predictions from the developed model,thus confirming the validity of the model.The alloy’s liquidus temperature,dendrite morphology,and hydrogen saturation solubility arising from different Cu contents have significant effects on microporosity morphology.The withdrawal rate primarily affects the nucleation of hydrogen microporosity by altering cooling rates and dendritic growth rates,resulting in different microporosity characteristics.展开更多
Polymers of intrinsic microporosity(PIMs)have received considerable attention for making high-performance membranes for carbon dioxide separation over the last two decades,owing to their highly permeable porous struct...Polymers of intrinsic microporosity(PIMs)have received considerable attention for making high-performance membranes for carbon dioxide separation over the last two decades,owing to their highly permeable porous structures.However,challenges regarding its relatively low selectivity,physical aging,and plasticisation impede relevant industrial adoptions for gas separation.To address these issues,several strategies including chain modification,post-modification,blending with other polymers,and the addition of fillers,have been developed and explored.PIM-1 is the most investigated PIMs,and hence here we review the stateof-the-arts of the modification strategies of PIM-1 critically and discuss the progress achieved for addressing the aforementioned challenges via meta-analysis.Additionally,the development of PIM-1-based thin film composite membranes is commented as well,shedding light on their potential in industrial gas separation.We hope that the review can be a timely snapshot of the relevant state-of-the-arts of PIMs guiding future design and optimisation of PIMs-based membranes for enhanced performance towards a higher technology readiness level for practical applications.展开更多
In order to study the effect of Zr modification and riser size on microporosity defect distributions in WE54 alloy sand castings, the microporosity volume percentage in Zr-free and Zr-containing WE54 alloy plate casti...In order to study the effect of Zr modification and riser size on microporosity defect distributions in WE54 alloy sand castings, the microporosity volume percentage in Zr-free and Zr-containing WE54 alloy plate castings was determined by density measurement based on Archimedes＇ principle, and the microstructure of the microporosity defects was observed by optical microscopy and scanning electron microscopy. Then by using Procast software, the Niyama criterion was calculated in order to investigate the validity of Niyama criterion on prediction of microporosity defects in WE54 alloy sand castings. It is found from the density measurement results that Zr addition does not affect the microporosity distributions in WE54 alloy castings. While the distribution area of microporosity defect in the plate castings decreases significantly as the riser size increases. Based on the experimental results, a riser selection principle for production of compact WE54 alloy castings is proposed that the solidification modulus of the riser should be greater than that of the casting by 30%, simply mr ≥ 1.3mc. By comparing the experimental and simulating results, it is found that the predicted microporosity regions by Niyama criterion agrees well with experimental results, and a critical Niyama value of 0.4 ℃0.5 s0.5 mm-1 is suggested for prediction of microporosity formation in WE54 alloy sand castings.展开更多
The study provides insight into the combined effect of sorbent surface functionalities and microporosity on2,2 ′,4,4 ′-tetrabromodiphenyl ether （BDE-47） sorption onto biochars. A series of biochars prepared underd...The study provides insight into the combined effect of sorbent surface functionalities and microporosity on2,2 ′,4,4 ′-tetrabromodiphenyl ether （BDE-47） sorption onto biochars. A series of biochars prepared underdifferent conditionswere used to test their sorption behaviorswith BDE-47. The extents of sorption behaviorswere parameterized in terms of the single-point adsorption equilibrium constant （Koc ） at three equilibrium concentration （C e ） levels （0.001Sw （solubility）, 0.005Sw , and 0.05Sw ）whichwasdetermined using the Freundlich model. To elucidate the concentration-dependentdominant mechanisms for BDE-47 sorption onto biochars, K ocwas correlatedwith four major parameters using multiple parameter linear analysis accompaniedwith significance testing. The results indicated that at low concentration （Ce = 0.001Sw ）, the surface microporosity term,which represented a pore-filling mechanism, contributed significantly to this relationship,while as concentrationwas increased to higher levels, surface functionality related to surface adsorption began to take thedominant role,whichwas further confirmed by the results of Polanyi-based modeling. Given the above results, adual mode model based on Dubinin-Radushkevich andde Boer-Zwikker equationswas adopted to quantitatively assess the changes of significance of surface adsorption aswell as that of pore fillingwith sorption processdevelopment. In addition, UV spectra of four typical aromatic compoundswhich represented the key structural fragments of biochars before and after interactionswith BDE-47were analyzed todetermine the active functional groups and supply complementary evidence for thedominant interaction force for surface adsorption, based onwhich π-π electron-donor-acceptor interactionwas proposed to contribute greatly to surface adsorption.展开更多
During the direct chill(DC)casting process,primary cooling from the mold and bottom block,and secondary cooling from the waterjets produce a concave solid shell.The depth of this liquid pocket and mushy zone not only ...During the direct chill(DC)casting process,primary cooling from the mold and bottom block,and secondary cooling from the waterjets produce a concave solid shell.The depth of this liquid pocket and mushy zone not only depends on the solidification range of the alloy but also the boundary conditions such as cooling rates.Al-Li alloys solidify in a long solidification range increasing the susceptibility of porosity nucleation in the semi-solid region.In this study,the effects of cooling rate on the porosity formation were quantified for the large ingot casting using X-ray computed tomography(XCT).By characterizing pore size distributions at four different cooling conditions,the correlation between the mechanical properties at both room and high temperatures and the microstructure features was identified.The constitutive equations were constructed.It is found that increasing the cooling rate reduces the grain size,increases the number density of micropores,and minimizes the number of large pores,thereby improving the mechanical performance.Therefore,long mushy zones and deep liquid pockets in Al-Li alloys can be effectively controlled by controlling the boundary conditions of the DC casting solidification process,thereby obtaining castings with excellent mechanical properties.展开更多
We simulate the evolution of hydrogen concentration and gas pore formation as equiaxed dendrites grow during solidification of a hypoeutectic aluminum-silicon(Al-Si)alloy.The applied lattice Boltzmann-cellular automat...We simulate the evolution of hydrogen concentration and gas pore formation as equiaxed dendrites grow during solidification of a hypoeutectic aluminum-silicon(Al-Si)alloy.The applied lattice Boltzmann-cellular automaton-finite difference model incorporates the physical mechanisms of solute and hydrogen partitioning on the solid/liquid interface,as well as the transports of solute and hydrogen.After the quantitative validation by the simulation of capillary intrusion,the model is utilized to investigate the growth of the equiaxed dendrites and hydrogen porosity formation for an Al-(5 wt.%)Si alloy under different solidification conditions.The simulation data reveal that the gas pores favorably nucleate in the corners surrounded by the nearby dendrite arms.Then,the gas pores grow in a competitive mode.With the cooling rate increasing,the competition among different growing gas pores is found to be hindered,which accordingly increases the pore number density in the final solidification microstructure.In the late solidification stage,even though the solid fraction is increasing,the mean concentration of hydrogen in the residue melt tends to be constant,corresponding to a dynamic equilibrium state of hydrogen concentration in liquid.As the cooling rate increases or the initial hydrogen concentration decreases,the temperature of gas pore nucleation,the porosity fraction,and the mean porosity size decrease,whilst the mean hydrogen concentration in liquid increases in the late solidification stage.The simulated data present identical trends with the experimental results reported in literature.展开更多
A mathematical model to calculate the size and distribution of microporosities was studied and coupled with a stochastic microstructure evolution model. The model incorporates various solidification phenomena such as ...A mathematical model to calculate the size and distribution of microporosities was studied and coupled with a stochastic microstructure evolution model. The model incorporates various solidification phenomena such as grain structure evolution, solidification shrinkage, interdendritic fluid flow and formation and growth of pores during solidification processes. The nucleation and growth of grains were modeled with a cellular automaton method that utilizes the results from a macro scale modeling of the solidification process. Experiments were made to validate the proposed models. The calculated results of aluminum alloy castings agreed with the experimental measurements.展开更多
Enhancing the water permeation while maintaining high salt rejection of existing reverse osmosis(RO)membranes remains a considerable challenge.Herein,we proposed to introduce polymer of intrinsic microporosity,PIM-1,i...Enhancing the water permeation while maintaining high salt rejection of existing reverse osmosis(RO)membranes remains a considerable challenge.Herein,we proposed to introduce polymer of intrinsic microporosity,PIM-1,into the selective layer of reverse osmosis membranes to break the trade-off effect between permeability and selectivity.A water-soluble a-LPIM-1 of low-molecular-weight and hydroxyl terminals was synthesized.These designed characteristics endowed it with high solubility and reactivity.Then it was mixed with m-phenylenediamine and together served as aqueous monomer to react with organic monomer of trimesoyl chloride via interfacial polymerization.The characterization results exhibited that more“nodule”rather than“leaf”structure formed on RO membrane surface,which indicated that the introduction of the high free-volume of a-LPIM-1 with three dimensional twisted and folded structure into the selective layer effectively caused the frustrated packing between polymer chains.In virtue of this effect,even with reduced surface roughness and unchanged layer thickness,the water permeability of prepared reverse osmosis membranes increased 2.1 times to 62.8 L·m^(-2)·h^(-1) with acceptable Na Cl rejection of 97.6%.This attempt developed a new strategy to break the trade-off effect faced by traditional polyamide reverse osmosis membranes.展开更多
In the present study, the contribution of the gas bubbling filtration （GBF） process to the microporosity variation, microstructural characteristics and tensile properties of A356 aluminium alloy was investigated. Th...In the present study, the contribution of the gas bubbling filtration （GBF） process to the microporosity variation, microstructural characteristics and tensile properties of A356 aluminium alloy was investigated. The test specimens were fabricated through gravity casting in terms of the process variables： the degassing time, the impeller rotation and the aperture size of gas inlet hole. The density measurement and scanning electron microscope fractography analyses were conducted to evaluate the variation of the volumetric porosity and fractographic porosity with the GBF process, respec- tively. The fractographic porosity of the specimens can be minimised under specific GBF conditions in terms of the buoyant velocity and the absorbing capacity of gas bubbles, the inclusion of oxide films, whereas the volumetric porosity can be wholly reduced on the lapse of degassing time. The ultimate tensile strength （UTS） and elongation at optimal conditions were improved to approximately 30 MPa and 1.5% compared with no GBF treatment. Even though an extension of the degassing time and/or excessive stirring action of the melt may induce the inclusion of bifilm oxides and the increase of fractographic porosity, the tensile properties of over-treated specimens were maintained to a level which is similar to those that did not undergo GBF treatment due to the grain refinement accompanying with the GBF process. In addition, the defect susceptibility of UTS and elongation to microporosity variation could be remarkably improved at an optimal GBF condition.展开更多
Polymers of intrinsic microporosity shows great potential for dye adsorption and magnetic Fe_(3)O_(4) are easy to be separated.In this work,hydrolyzed polymers of intrinsic microporosity-1/Fe_(3)O_(4) composite adsorb...Polymers of intrinsic microporosity shows great potential for dye adsorption and magnetic Fe_(3)O_(4) are easy to be separated.In this work,hydrolyzed polymers of intrinsic microporosity-1/Fe_(3)O_(4) composite adsorbents were prepared by phase inversion and hydrolysis process for cationic dye adsorption.The chemical structure and morphology of the composite adsorbents were systematically characterized by several characterization methods.Using methylene blue as the target dye,the influences of solution pH,contact time,initial dye concentration,and system temperature on the methylene blue adsorption process were investigated.The incorporation of Fe_(3)O_(4) particle into hydrolyzed polymers of intrinsic microporosity-1 endow the adsorbent with high magnetic saturation(20.7 emu·g^(–1))which allows the rapid separation of the adsorbent.Furthermore,the adsorption process was simulated by adsorption kinetics,isotherms and thermodynamics to gain insight onto the intrinsic adsorption mechanism.In addition,the composite adsorbents are able to selectively adsorb cationic dyes from mixed dyes solution.Hydrolyzed polymers of intrinsic microporosity/Fe_(3)O_(4) shows only a slight decrease for methylene blue adsorption after 10 adsorption/regeneration cycles,demonstrating the outstanding regeneration performance.The high adsorption capacity,outstanding regeneration ability,together with simple preparation method,endow the composite adsorbents great potential for selective removal of cationic dyes in wastewater system.展开更多
Microporosity has a critical role in improving the osteogenesis of scaffolds for bone tissue engineering.Although the exact mechanism,by which it promotes new bone formation,is not well recognized yet,the related hypo...Microporosity has a critical role in improving the osteogenesis of scaffolds for bone tissue engineering.Although the exact mechanism,by which it promotes new bone formation,is not well recognized yet,the related hypothesis can be found in many previous studies.This review presents those possible mechanisms about how the microporosity enhances the osteogenic-related functions of cells in vitro and the osteogenic activity of scaffolds in vivo.In summary,the increased specific surface areas by microporosity can offer more protein adsorption sites and accelerate the release of degradation products,which facilitate the interactions between scaffolds and cells.Meanwhile,the unique surface properties of microporous scaffolds have a considerable effect on the protein adsorption.Moreover,capillary force generated by the microporosity can improve the attachment of bone-related cells on the scaffolds surface,and even make the cells achieve penetration into the micropores smaller than them.This review also pays attention to the relationship between the biological and mechanical properties of microporous scaffolds.Although lots of achievements have been obtained,there is still a lot of work to do,some of which has been proposed in the conclusions and perspectives part.展开更多
Polymers of intrinsic microporosity （PIMs） are a class of porous organic polymer （POP） that form microporous solids due to the inefficient packing of their rigid and contorted macromolecular chains. In contrast to...Polymers of intrinsic microporosity （PIMs） are a class of porous organic polymer （POP） that form microporous solids due to the inefficient packing of their rigid and contorted macromolecular chains. In contrast to other types of POP, PIMs are not comprised of a network of cross-linked covalent bonds so that they can be dissolved in organic solvents and processed into robust films, coatings or fibres. Here, over twelve years＇ accumulated research on the synthesis of PIMs is reviewed. To date, three types of polymerisation reaction have been used successfully to prepare PIMs of sufficient molecular mass to form robust self-standing films. These involve the formation of dibenzodioxin, Tr6ger＇s base and imide linkages between monomeric units. This rapid development of synthetic methods for preparing PIMs has been driven by their rich potential for numerous diverse applications and this synergistic relationship between synthesis and functionality is set to continue.展开更多
Membrane separation technology offers a green,efficient and energy-saving approach for biogas upgrading.Membranes with high selectivity and high permeability are the key to achieve high performance.Polymers of Intrins...Membrane separation technology offers a green,efficient and energy-saving approach for biogas upgrading.Membranes with high selectivity and high permeability are the key to achieve high performance.Polymers of Intrinsic Microporosity(PIMs)materials have shown excellent gas permeability but low selectivity which limits their practical application.Herein,a polyphenol,tannic acid,was coated on the PIM-1 membrane surface by a facile dipping method to fabricate composite membranes.Tannic acid containing a large number of polar oxygencontaining groups(quinone,phenolic hydroxyl)self-polymerized on the membrane surface to form a CO2-philic,defect-free and thin layer.The CO2/CH4 selectivity of the resultant composite membranes was increased after tannic acid coating while the permeability remained comparable to or even higher than pristine PIM-1 membrane,exceeding the reported 2008 upper bound.展开更多
The design and development of highly permeable,selective and stable polymer membranes are great challenges in the gas separation industry.Herein,we constructed two intrinsic microporous polyimides(6FPCA and 6FMCA)deri...The design and development of highly permeable,selective and stable polymer membranes are great challenges in the gas separation industry.Herein,we constructed two intrinsic microporous polyimides(6FPCA and 6FMCA)derived from two isometric diamines(PCA and MCA),which were synthesized by palladium catalyzed C—N coupling reaction.The PCA and MCA diamines contain a hollow beaded structure of 2,2′-paracyclophane as a building block with a specified window size of 3.09Å.The chemical structures of monomers,polyimides were confirmed by NMR,FTIR,and elementary analysis.6FPCA and 6FMCA exhibit good solubility,excellent thermal stability,and mechanical properties.6FPCA exhibits much larger microporosity(434 versus 120 m2·g−1),FFV(0.22 versus 0.15),d-spacing(6.9 versus 5.9Å),and over 10 times higher permeability with a very little decrease in selectivity than the corresponding polyimide(6FpA)with a plane structure,which remarkably increased their separation performance from far below the 2008 Robeson Upper bounds to reach these limitations for O2/N2 and CO2/CH4.Additionally,the 6FPCA also demonstrates good plasticization resistance,moderate aging properties,and high CO2/CH4 mixed-gas separation performance.These results indicate that paracyclophane subunit can be successfully incorporated into polymers to enhance their ultra-microporosity and separation properties,which open a new avenue for developing high performance gas separation membranes with topological ultra-micropores.展开更多
Carbonate rocks are important hydrocarbon reservoirs around the globe and in Southeast Asia a key one,particularly,is the Central Luconia province.Understanding the internal characteristics,distribution,geometry and l...Carbonate rocks are important hydrocarbon reservoirs around the globe and in Southeast Asia a key one,particularly,is the Central Luconia province.Understanding the internal characteristics,distribution,geometry and lateral extent of these rocks is essential for exploration and production success.Detailed work on Miocene carbonate reservoir facies,north of Bintulu,offshore Sarawak includes qualitative and quantitative analysis of photomicrographs and reservoir quality,considering especially microporosity.Stratigraphically,these carbonates are known as Cycles IV and V and are represented by eight major facies types(F-1 to F-8).They comprise:coated grain packstone(F-1)(av.Ф=3%,av.Kh=0.5 m D)(av=Average;?=total porosity,and Kh=permeability);massive coral lime grainstone(F-2)(av.Ф=14.7%,av.Kh=6 m D);oncolite lime grain-dominated packstone(F-3)(av.Ф=10%,av.Kh=4 m D);skeletal lime/dolo-packstone(F-4)(av.Ф=15%,av.Kh=4.6 m D);coral(platy)lime mud-dominated packstone(F-5)(av.Ф=4%,av.Kh=0.5 m D);coral(branching)lime-dominated pack-grainstone(F-6)(av.Ф=15%,av.Kh=1 m D);cross-bedded skeletal lime packstone(F-7)(av.Ф=20%,av.Kh=2 m D);and bioturbated carbonate mudstone/chalk(F-8)(av.Ф=8%,av.Kh=0.8 m D).Study of thin sections reveals that red algae,foraminifera,and corals are the dominant fossil components with a minor admixture of skeletal fragments of echinoderms,bivalves,bryozoans,and green algae.All parameters,e.g.,facies characterization,petrography,porosity–permeability value,and microporosity value were utilized to obtain a reliable reservoir quality.The microporosity value was quantified using digital image analysis software and is significant for recognition of good reservoir quality.Consideration of the presence of microporosity against the total porosity in the carbonate rocks has improved the correlation coefficient(R2)value,which has increased from 0.51 to 0.82.展开更多
Porosity formation during solidification of aluminum-based alloys,due to hydrogen gas and alloy shrinkage,has been a major issue adversely affecting the performance of solidification products such as castings,welds or...Porosity formation during solidification of aluminum-based alloys,due to hydrogen gas and alloy shrinkage,has been a major issue adversely affecting the performance of solidification products such as castings,welds or additively manufactured components.A three-dimensional cellular automaton(CA)model has been developed,for the first time,to couple the predictions of hydrogen-induced gas porosity and shrinkage porosity during solidification microstructure evolution of a binary Al-Si alloy.The CA simulation results are validated under various cooling rates by porosity measurements in an experimental wedge die casting using X-ray micro computed tomography(XMCT)technique.This validated porosity moel provides a critical link in integrated computation materials engineering(ICME)design and manufacturing of solidification products.展开更多
Two novel compounds, {[Co2（epda）2（4,4＇-bpy）（H20）z]＇3H20}n 1 and {[Co2（epda）2（bpe）（HzO）z]＇3HzO}n 2 （H2epda = 5-ethyl-pyridine-2,3-dicarboxylic acid, 4,4＇-bpy = 4,4＇-bipyridine and bpe = 1,2-di（4-pyri...Two novel compounds, {[Co2（epda）2（4,4＇-bpy）（H20）z]＇3H20}n 1 and {[Co2（epda）2（bpe）（HzO）z]＇3HzO}n 2 （H2epda = 5-ethyl-pyridine-2,3-dicarboxylic acid, 4,4＇-bpy = 4,4＇-bipyridine and bpe = 1,2-di（4-pyridyl）ethylene） were solvothermally synthesized and charac- terized by elemental analysis, IR spectroscopy, thermogravimetric analysis （TGA）, and single- crystal X-ray diffraction. Complex 1 is ofmonoclinic system, space group P21/c with a = 13.344（5）, b = 14.724（5）, c = 8.267（3） A, fl = 105.840（4）~, V= 1562.5（10） A3, Dc = 1.480 g/cm3, Mr = 375.19, Z = 4, F（000） = 712, gl = 1.121 mm-1, the final R = 0.0512 and wR = 0.1260 for 2890 observed reflections with I 〉 2σ（I）. 2 belongs to the monoclinic system, space group P21/c with a = 14.224（4）, b = 14.726（4）, c = 8.287（2） A,β = 99.696（4）°, V= 1711.1（9） A3, Dc = 1.402 g/cm3, Mr = 388.21, Z = 4, F（000） = 740, kt = 1.027 mm-1, the final R = 0.0354 and wR = 0.0862 for 12237 observed reflections with I 〉 2a（/）. Both complexes present intimately related structures featuring infinite Co-carboxylate layers of [Con（epda）（H20）]n pillared by 4,4＇-bpy （or bpe） molecule to produce the microporous frameworks, Unambiguously indicating that pore dimensions of the framework are regulated by the N,N＇-donor pillars.展开更多
The microstructural analysis of muds and mudrocks requires very high-resolution measurement. Recent advances in electron microscopy have contributed significantly to the improved characterisation of mudrock microstruc...The microstructural analysis of muds and mudrocks requires very high-resolution measurement. Recent advances in electron microscopy have contributed significantly to the improved characterisation of mudrock microstructures and their consequent petrophysical properties. However, imaging through electron microscopy is limited to small areas of coverage such that upscaling of these properties is a great challenge. In this paper, we develop a new methodology for multiple large-area imaging using scanning electron microscopy through automated acquisition and stitching from polished thin-sections and ion-milled samples. The process is fast, efficient and minimises user-input and bias. It can provide reliable, quantifiable data on sediment grain size, grain orientation, pore size and porosity. Limitations include the time involved for individual runs and manual segmentation, the large amount of computer memory required, and instrument resolution at the nano-scale. This method is applied to selected samples of Quaternary muddy sediments from the Iberian margin at IODP Site 1385. The section comprises finegrained(very fine clayey silts), mixed-composition, biogenic-terrigenous hemipelagites, with a pronounced but non-regular colour cyclicity. There is a multi-tiered and diverse trace fossil assemblage of the deep-water Zoophycos ichnofacies. The sediment microstructures show small-scale heterogeneity in all properties, and an overall random fabric with secondary preferred grain-alignment. These results on the fabric differ, in part, from previous studies of hemipelagic muds. Further work is underway on their comparison with other deep-water sediment facies.展开更多
A novel two-step procedure was used to manufacture microporous activated carbon from raw coconut shell. In this process, the raw coconut shell was （1） heated in an inert environment to temperatures between 450℃ and...A novel two-step procedure was used to manufacture microporous activated carbon from raw coconut shell. In this process, the raw coconut shell was （1） heated in an inert environment to temperatures between 450℃ and 850℃, and reacted with oxygen （ PO2=1.1-5.3kPa） for some time, and （2） heated again in inert environment to activation temperature（850℃） to produce an activated carbon. Activated carbons with specific surface area greater than 700m^2.g^-1 were manufactured with a yield between 24% and 28%. It was shown that the carbon had a narrow distribution of pore size, possibly less than lnm, which was calculated by a simple method based on local density function theory.展开更多
基金financial support from the National Natural Science Foundation of China(Nos.22108258 and 52003251)Program for Science&Technology Innovation Talents in Universities of Henan Province(24HASTIT004)+1 种基金Outstanding Youth Fund of Henan Scientific Committee(222300420085)Science and Technology Joint Project of Henan Province(222301420041)。
文摘Mixed matrix membranes(MMMs)have demonstrated significant promise in energy-intensive gas separations by amalgamating the unique properties of fillers with the facile processability of polymers.However,achieving a simultaneous enhancement of permeability and selectivity remains a formidable challenge,due to the difficulty of achieving an optimal match between polymers and fillers.In this study,we incorporate a porous carbon-based zinc oxide composite(C@ZnO)into high-permeability polymers of intrinsic microporosity(PIMs)to fabricate MMMs.The dipole–dipole interaction between C@ZnO and PIMs ensures their exceptional compatibility,mitigating the formation of non-selective voids in the resulting MMMs.Concurrently,C@ZnO with abundant interconnected pores can provide additional low-resistance pathways for gas transport in MMMs.As a result,the CO_(2) permeability of the optimized C@ZnO/PIM-1 MMMs is elevated to 13,215 barrer,while the CO_(2)/N_(2) and CO_(2)/CH_(4) selectivity reached 21.5 and 14.4,respectively,substantially surpassing the 2008 Robeson upper bound.Additionally,molecular simulation results further corroborate that the augmented membrane gas selectivity is attributed to the superior CO_(2) affinity of C@ZnO.In summary,we believe that this work not only expands the application of MMMs for gas separation but also heralds a paradigm shift in the application of porous carbon materials.
基金financially supported by the National Natural Science Foundation of China(Grant No.51875211)the Beijing Natural Science Foundation(Grant No.L223001)。
文摘Microporosity formed in the solidification process of Al alloys is detrimental to the alloy properties.A two-dimensional cellular automaton(CA)model was developed to simulate the microstructure and microporosity formation in Al-Cu alloys,considering variations in Cu content and solidification rate.The results indicate that the Cu content primarily influences the growth of microporosity.To validate the model,directional solidification experiments were conducted on Al-Cu alloys with varing Cu contents and withdrawal rates.The experimental results of dendrites and microporosity characteristics agree well with the predictions from the developed model,thus confirming the validity of the model.The alloy’s liquidus temperature,dendrite morphology,and hydrogen saturation solubility arising from different Cu contents have significant effects on microporosity morphology.The withdrawal rate primarily affects the nucleation of hydrogen microporosity by altering cooling rates and dendritic growth rates,resulting in different microporosity characteristics.
基金funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 872102the China Scholarship Council(CSC,file no.202006240076)-University of Manchester joint studentship for supporting the PhD researchthe special innovation project fund from the Institute of Wenzhou,Zhejiang University(No.XMGL-KJZX-202204)。
文摘Polymers of intrinsic microporosity(PIMs)have received considerable attention for making high-performance membranes for carbon dioxide separation over the last two decades,owing to their highly permeable porous structures.However,challenges regarding its relatively low selectivity,physical aging,and plasticisation impede relevant industrial adoptions for gas separation.To address these issues,several strategies including chain modification,post-modification,blending with other polymers,and the addition of fillers,have been developed and explored.PIM-1 is the most investigated PIMs,and hence here we review the stateof-the-arts of the modification strategies of PIM-1 critically and discuss the progress achieved for addressing the aforementioned challenges via meta-analysis.Additionally,the development of PIM-1-based thin film composite membranes is commented as well,shedding light on their potential in industrial gas separation.We hope that the review can be a timely snapshot of the relevant state-of-the-arts of PIMs guiding future design and optimisation of PIMs-based membranes for enhanced performance towards a higher technology readiness level for practical applications.
基金supported by the National Basic Research Program of China(973 Program,No.2013CB632202)
文摘In order to study the effect of Zr modification and riser size on microporosity defect distributions in WE54 alloy sand castings, the microporosity volume percentage in Zr-free and Zr-containing WE54 alloy plate castings was determined by density measurement based on Archimedes＇ principle, and the microstructure of the microporosity defects was observed by optical microscopy and scanning electron microscopy. Then by using Procast software, the Niyama criterion was calculated in order to investigate the validity of Niyama criterion on prediction of microporosity defects in WE54 alloy sand castings. It is found from the density measurement results that Zr addition does not affect the microporosity distributions in WE54 alloy castings. While the distribution area of microporosity defect in the plate castings decreases significantly as the riser size increases. Based on the experimental results, a riser selection principle for production of compact WE54 alloy castings is proposed that the solidification modulus of the riser should be greater than that of the casting by 30%, simply mr ≥ 1.3mc. By comparing the experimental and simulating results, it is found that the predicted microporosity regions by Niyama criterion agrees well with experimental results, and a critical Niyama value of 0.4 ℃0.5 s0.5 mm-1 is suggested for prediction of microporosity formation in WE54 alloy sand castings.
基金supported by the Special Environmental Research Funds for Public Welfare(No.201209053)
文摘The study provides insight into the combined effect of sorbent surface functionalities and microporosity on2,2 ′,4,4 ′-tetrabromodiphenyl ether （BDE-47） sorption onto biochars. A series of biochars prepared underdifferent conditionswere used to test their sorption behaviorswith BDE-47. The extents of sorption behaviorswere parameterized in terms of the single-point adsorption equilibrium constant （Koc ） at three equilibrium concentration （C e ） levels （0.001Sw （solubility）, 0.005Sw , and 0.05Sw ）whichwasdetermined using the Freundlich model. To elucidate the concentration-dependentdominant mechanisms for BDE-47 sorption onto biochars, K ocwas correlatedwith four major parameters using multiple parameter linear analysis accompaniedwith significance testing. The results indicated that at low concentration （Ce = 0.001Sw ）, the surface microporosity term,which represented a pore-filling mechanism, contributed significantly to this relationship,while as concentrationwas increased to higher levels, surface functionality related to surface adsorption began to take thedominant role,whichwas further confirmed by the results of Polanyi-based modeling. Given the above results, adual mode model based on Dubinin-Radushkevich andde Boer-Zwikker equationswas adopted to quantitatively assess the changes of significance of surface adsorption aswell as that of pore fillingwith sorption processdevelopment. In addition, UV spectra of four typical aromatic compoundswhich represented the key structural fragments of biochars before and after interactionswith BDE-47were analyzed todetermine the active functional groups and supply complementary evidence for thedominant interaction force for surface adsorption, based onwhich π-π electron-donor-acceptor interactionwas proposed to contribute greatly to surface adsorption.
基金supported by the National Natural Science Foundation of China(Project number:52073030).
文摘During the direct chill(DC)casting process,primary cooling from the mold and bottom block,and secondary cooling from the waterjets produce a concave solid shell.The depth of this liquid pocket and mushy zone not only depends on the solidification range of the alloy but also the boundary conditions such as cooling rates.Al-Li alloys solidify in a long solidification range increasing the susceptibility of porosity nucleation in the semi-solid region.In this study,the effects of cooling rate on the porosity formation were quantified for the large ingot casting using X-ray computed tomography(XCT).By characterizing pore size distributions at four different cooling conditions,the correlation between the mechanical properties at both room and high temperatures and the microstructure features was identified.The constitutive equations were constructed.It is found that increasing the cooling rate reduces the grain size,increases the number density of micropores,and minimizes the number of large pores,thereby improving the mechanical performance.Therefore,long mushy zones and deep liquid pockets in Al-Li alloys can be effectively controlled by controlling the boundary conditions of the DC casting solidification process,thereby obtaining castings with excellent mechanical properties.
基金Project supported by the National Natural Science Foundation of China(Grant No.51901148)the Fund of the State Key Laboratory of Solidification Processing(Northwestern Polytechnical University),China(Grant No.SKLSP202006)the State Key Lab of Advanced Metals and Materials(University of Science and Technology Beijing),China(Grant No.2019-Z15).
文摘We simulate the evolution of hydrogen concentration and gas pore formation as equiaxed dendrites grow during solidification of a hypoeutectic aluminum-silicon(Al-Si)alloy.The applied lattice Boltzmann-cellular automaton-finite difference model incorporates the physical mechanisms of solute and hydrogen partitioning on the solid/liquid interface,as well as the transports of solute and hydrogen.After the quantitative validation by the simulation of capillary intrusion,the model is utilized to investigate the growth of the equiaxed dendrites and hydrogen porosity formation for an Al-(5 wt.%)Si alloy under different solidification conditions.The simulation data reveal that the gas pores favorably nucleate in the corners surrounded by the nearby dendrite arms.Then,the gas pores grow in a competitive mode.With the cooling rate increasing,the competition among different growing gas pores is found to be hindered,which accordingly increases the pore number density in the final solidification microstructure.In the late solidification stage,even though the solid fraction is increasing,the mean concentration of hydrogen in the residue melt tends to be constant,corresponding to a dynamic equilibrium state of hydrogen concentration in liquid.As the cooling rate increases or the initial hydrogen concentration decreases,the temperature of gas pore nucleation,the porosity fraction,and the mean porosity size decrease,whilst the mean hydrogen concentration in liquid increases in the late solidification stage.The simulated data present identical trends with the experimental results reported in literature.
基金supported by the key project of NSFC(59990470-3)State Significant Fundamental Research Program of MOST(G2000067208-3).
文摘A mathematical model to calculate the size and distribution of microporosities was studied and coupled with a stochastic microstructure evolution model. The model incorporates various solidification phenomena such as grain structure evolution, solidification shrinkage, interdendritic fluid flow and formation and growth of pores during solidification processes. The nucleation and growth of grains were modeled with a cellular automaton method that utilizes the results from a macro scale modeling of the solidification process. Experiments were made to validate the proposed models. The calculated results of aluminum alloy castings agreed with the experimental measurements.
基金supported by Zhejiang Provincial Natural Science Foundation of China (LZ20B060001)National Natural Science Foundation of China (22008208&21908192)China Postdoctoral Science Foundation (2019TQ0276)。
文摘Enhancing the water permeation while maintaining high salt rejection of existing reverse osmosis(RO)membranes remains a considerable challenge.Herein,we proposed to introduce polymer of intrinsic microporosity,PIM-1,into the selective layer of reverse osmosis membranes to break the trade-off effect between permeability and selectivity.A water-soluble a-LPIM-1 of low-molecular-weight and hydroxyl terminals was synthesized.These designed characteristics endowed it with high solubility and reactivity.Then it was mixed with m-phenylenediamine and together served as aqueous monomer to react with organic monomer of trimesoyl chloride via interfacial polymerization.The characterization results exhibited that more“nodule”rather than“leaf”structure formed on RO membrane surface,which indicated that the introduction of the high free-volume of a-LPIM-1 with three dimensional twisted and folded structure into the selective layer effectively caused the frustrated packing between polymer chains.In virtue of this effect,even with reduced surface roughness and unchanged layer thickness,the water permeability of prepared reverse osmosis membranes increased 2.1 times to 62.8 L·m^(-2)·h^(-1) with acceptable Na Cl rejection of 97.6%.This attempt developed a new strategy to break the trade-off effect faced by traditional polyamide reverse osmosis membranes.
基金supported by the General Researcher Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education,Science and Technology(2010-0022284)+1 种基金supported by the Development Program for Industrial Core-Technology through the Korea Evaluation Institute of Industrial Technology(KEIT)funded by the Ministry of Trade,Industry and Energy(10048817)
文摘In the present study, the contribution of the gas bubbling filtration （GBF） process to the microporosity variation, microstructural characteristics and tensile properties of A356 aluminium alloy was investigated. The test specimens were fabricated through gravity casting in terms of the process variables： the degassing time, the impeller rotation and the aperture size of gas inlet hole. The density measurement and scanning electron microscope fractography analyses were conducted to evaluate the variation of the volumetric porosity and fractographic porosity with the GBF process, respec- tively. The fractographic porosity of the specimens can be minimised under specific GBF conditions in terms of the buoyant velocity and the absorbing capacity of gas bubbles, the inclusion of oxide films, whereas the volumetric porosity can be wholly reduced on the lapse of degassing time. The ultimate tensile strength （UTS） and elongation at optimal conditions were improved to approximately 30 MPa and 1.5% compared with no GBF treatment. Even though an extension of the degassing time and/or excessive stirring action of the melt may induce the inclusion of bifilm oxides and the increase of fractographic porosity, the tensile properties of over-treated specimens were maintained to a level which is similar to those that did not undergo GBF treatment due to the grain refinement accompanying with the GBF process. In addition, the defect susceptibility of UTS and elongation to microporosity variation could be remarkably improved at an optimal GBF condition.
基金supported by the National Natural Science Foundation of China(Grant Nos.22178327 and 52003250)China Postdoctoral Science Foundation(Grant No.2020M682351)+1 种基金Excellent Youth Foundation of Henan Scientific Committee(Grant No.222300420018)Key Scientific Research Project of Universities in Henan Province(Grant No.21zx006).
文摘Polymers of intrinsic microporosity shows great potential for dye adsorption and magnetic Fe_(3)O_(4) are easy to be separated.In this work,hydrolyzed polymers of intrinsic microporosity-1/Fe_(3)O_(4) composite adsorbents were prepared by phase inversion and hydrolysis process for cationic dye adsorption.The chemical structure and morphology of the composite adsorbents were systematically characterized by several characterization methods.Using methylene blue as the target dye,the influences of solution pH,contact time,initial dye concentration,and system temperature on the methylene blue adsorption process were investigated.The incorporation of Fe_(3)O_(4) particle into hydrolyzed polymers of intrinsic microporosity-1 endow the adsorbent with high magnetic saturation(20.7 emu·g^(–1))which allows the rapid separation of the adsorbent.Furthermore,the adsorption process was simulated by adsorption kinetics,isotherms and thermodynamics to gain insight onto the intrinsic adsorption mechanism.In addition,the composite adsorbents are able to selectively adsorb cationic dyes from mixed dyes solution.Hydrolyzed polymers of intrinsic microporosity/Fe_(3)O_(4) shows only a slight decrease for methylene blue adsorption after 10 adsorption/regeneration cycles,demonstrating the outstanding regeneration performance.The high adsorption capacity,outstanding regeneration ability,together with simple preparation method,endow the composite adsorbents great potential for selective removal of cationic dyes in wastewater system.
基金the financial supports from the National Natural Science Foundation of China(Nos.31370959 and 31771042)National Key R&D Program of China(No.2017YFC1104703)+3 种基金Beijing Nova Programme Interdisciplinary Cooperation Project(No.xxjc201616)Fok Ying Tung Education Foundation(No.141039)State Key Laboratory of New Ceramic and Fine Processing Tsinghua University(No.KF201714)International Joint Research Center of Aerospace Biotechnology and Medical Engineering,Ministry of Science and Technology of China,and the 111 Project(No.B13003).
文摘Microporosity has a critical role in improving the osteogenesis of scaffolds for bone tissue engineering.Although the exact mechanism,by which it promotes new bone formation,is not well recognized yet,the related hypothesis can be found in many previous studies.This review presents those possible mechanisms about how the microporosity enhances the osteogenic-related functions of cells in vitro and the osteogenic activity of scaffolds in vivo.In summary,the increased specific surface areas by microporosity can offer more protein adsorption sites and accelerate the release of degradation products,which facilitate the interactions between scaffolds and cells.Meanwhile,the unique surface properties of microporous scaffolds have a considerable effect on the protein adsorption.Moreover,capillary force generated by the microporosity can improve the attachment of bone-related cells on the scaffolds surface,and even make the cells achieve penetration into the micropores smaller than them.This review also pays attention to the relationship between the biological and mechanical properties of microporous scaffolds.Although lots of achievements have been obtained,there is still a lot of work to do,some of which has been proposed in the conclusions and perspectives part.
文摘Polymers of intrinsic microporosity （PIMs） are a class of porous organic polymer （POP） that form microporous solids due to the inefficient packing of their rigid and contorted macromolecular chains. In contrast to other types of POP, PIMs are not comprised of a network of cross-linked covalent bonds so that they can be dissolved in organic solvents and processed into robust films, coatings or fibres. Here, over twelve years＇ accumulated research on the synthesis of PIMs is reviewed. To date, three types of polymerisation reaction have been used successfully to prepare PIMs of sufficient molecular mass to form robust self-standing films. These involve the formation of dibenzodioxin, Tr6ger＇s base and imide linkages between monomeric units. This rapid development of synthetic methods for preparing PIMs has been driven by their rich potential for numerous diverse applications and this synergistic relationship between synthesis and functionality is set to continue.
基金This work was supported by National Natural Science Foundation of China(No.U20B2023,21838008,21621004)Program of Introducing Talents of Discipline to Universities(No.BP0618007).
文摘Membrane separation technology offers a green,efficient and energy-saving approach for biogas upgrading.Membranes with high selectivity and high permeability are the key to achieve high performance.Polymers of Intrinsic Microporosity(PIMs)materials have shown excellent gas permeability but low selectivity which limits their practical application.Herein,a polyphenol,tannic acid,was coated on the PIM-1 membrane surface by a facile dipping method to fabricate composite membranes.Tannic acid containing a large number of polar oxygencontaining groups(quinone,phenolic hydroxyl)self-polymerized on the membrane surface to form a CO2-philic,defect-free and thin layer.The CO2/CH4 selectivity of the resultant composite membranes was increased after tannic acid coating while the permeability remained comparable to or even higher than pristine PIM-1 membrane,exceeding the reported 2008 upper bound.
基金financially supported by the National Natural Science Foundation of China (Nos. 22078245 and 21861016)YLU-DNL Fund (No. 2022009)
文摘The design and development of highly permeable,selective and stable polymer membranes are great challenges in the gas separation industry.Herein,we constructed two intrinsic microporous polyimides(6FPCA and 6FMCA)derived from two isometric diamines(PCA and MCA),which were synthesized by palladium catalyzed C—N coupling reaction.The PCA and MCA diamines contain a hollow beaded structure of 2,2′-paracyclophane as a building block with a specified window size of 3.09Å.The chemical structures of monomers,polyimides were confirmed by NMR,FTIR,and elementary analysis.6FPCA and 6FMCA exhibit good solubility,excellent thermal stability,and mechanical properties.6FPCA exhibits much larger microporosity(434 versus 120 m2·g−1),FFV(0.22 versus 0.15),d-spacing(6.9 versus 5.9Å),and over 10 times higher permeability with a very little decrease in selectivity than the corresponding polyimide(6FpA)with a plane structure,which remarkably increased their separation performance from far below the 2008 Robeson Upper bounds to reach these limitations for O2/N2 and CO2/CH4.Additionally,the 6FPCA also demonstrates good plasticization resistance,moderate aging properties,and high CO2/CH4 mixed-gas separation performance.These results indicate that paracyclophane subunit can be successfully incorporated into polymers to enhance their ultra-microporosity and separation properties,which open a new avenue for developing high performance gas separation membranes with topological ultra-micropores.
基金Professor Dr.Deva Prasad Ghosh(Head:Centre for Seismic Imaging,Department of Geoscience,University Technology PETRONAS,Tronoh,Perak,Malaysia)for his support and economic assistance throughout the research under grant YUTP 0153AA-A14。
文摘Carbonate rocks are important hydrocarbon reservoirs around the globe and in Southeast Asia a key one,particularly,is the Central Luconia province.Understanding the internal characteristics,distribution,geometry and lateral extent of these rocks is essential for exploration and production success.Detailed work on Miocene carbonate reservoir facies,north of Bintulu,offshore Sarawak includes qualitative and quantitative analysis of photomicrographs and reservoir quality,considering especially microporosity.Stratigraphically,these carbonates are known as Cycles IV and V and are represented by eight major facies types(F-1 to F-8).They comprise:coated grain packstone(F-1)(av.Ф=3%,av.Kh=0.5 m D)(av=Average;?=total porosity,and Kh=permeability);massive coral lime grainstone(F-2)(av.Ф=14.7%,av.Kh=6 m D);oncolite lime grain-dominated packstone(F-3)(av.Ф=10%,av.Kh=4 m D);skeletal lime/dolo-packstone(F-4)(av.Ф=15%,av.Kh=4.6 m D);coral(platy)lime mud-dominated packstone(F-5)(av.Ф=4%,av.Kh=0.5 m D);coral(branching)lime-dominated pack-grainstone(F-6)(av.Ф=15%,av.Kh=1 m D);cross-bedded skeletal lime packstone(F-7)(av.Ф=20%,av.Kh=2 m D);and bioturbated carbonate mudstone/chalk(F-8)(av.Ф=8%,av.Kh=0.8 m D).Study of thin sections reveals that red algae,foraminifera,and corals are the dominant fossil components with a minor admixture of skeletal fragments of echinoderms,bivalves,bryozoans,and green algae.All parameters,e.g.,facies characterization,petrography,porosity–permeability value,and microporosity value were utilized to obtain a reliable reservoir quality.The microporosity value was quantified using digital image analysis software and is significant for recognition of good reservoir quality.Consideration of the presence of microporosity against the total porosity in the carbonate rocks has improved the correlation coefficient(R2)value,which has increased from 0.51 to 0.82.
基金the National Science Foundation for supporting this work(Award CMMI-1432688)supported by Honda R&D Americas(Raymond,Ohio)。
文摘Porosity formation during solidification of aluminum-based alloys,due to hydrogen gas and alloy shrinkage,has been a major issue adversely affecting the performance of solidification products such as castings,welds or additively manufactured components.A three-dimensional cellular automaton(CA)model has been developed,for the first time,to couple the predictions of hydrogen-induced gas porosity and shrinkage porosity during solidification microstructure evolution of a binary Al-Si alloy.The CA simulation results are validated under various cooling rates by porosity measurements in an experimental wedge die casting using X-ray micro computed tomography(XMCT)technique.This validated porosity moel provides a critical link in integrated computation materials engineering(ICME)design and manufacturing of solidification products.
基金supported by the National Natural Science Foundation of China (Nos. 20971064 and 21071074)the Foundation for University Young Key Teacher by Henan Province (No. 2011GGJS-153)
文摘Two novel compounds, {[Co2（epda）2（4,4＇-bpy）（H20）z]＇3H20}n 1 and {[Co2（epda）2（bpe）（HzO）z]＇3HzO}n 2 （H2epda = 5-ethyl-pyridine-2,3-dicarboxylic acid, 4,4＇-bpy = 4,4＇-bipyridine and bpe = 1,2-di（4-pyridyl）ethylene） were solvothermally synthesized and charac- terized by elemental analysis, IR spectroscopy, thermogravimetric analysis （TGA）, and single- crystal X-ray diffraction. Complex 1 is ofmonoclinic system, space group P21/c with a = 13.344（5）, b = 14.724（5）, c = 8.267（3） A, fl = 105.840（4）~, V= 1562.5（10） A3, Dc = 1.480 g/cm3, Mr = 375.19, Z = 4, F（000） = 712, gl = 1.121 mm-1, the final R = 0.0512 and wR = 0.1260 for 2890 observed reflections with I 〉 2σ（I）. 2 belongs to the monoclinic system, space group P21/c with a = 14.224（4）, b = 14.726（4）, c = 8.287（2） A,β = 99.696（4）°, V= 1711.1（9） A3, Dc = 1.402 g/cm3, Mr = 388.21, Z = 4, F（000） = 740, kt = 1.027 mm-1, the final R = 0.0354 and wR = 0.0862 for 12237 observed reflections with I 〉 2a（/）. Both complexes present intimately related structures featuring infinite Co-carboxylate layers of [Con（epda）（H20）]n pillared by 4,4＇-bpy （or bpe） molecule to produce the microporous frameworks, Unambiguously indicating that pore dimensions of the framework are regulated by the N,N＇-donor pillars.
基金the sponsorship received from Petroleum Technology Development Fund, Nigeria
文摘The microstructural analysis of muds and mudrocks requires very high-resolution measurement. Recent advances in electron microscopy have contributed significantly to the improved characterisation of mudrock microstructures and their consequent petrophysical properties. However, imaging through electron microscopy is limited to small areas of coverage such that upscaling of these properties is a great challenge. In this paper, we develop a new methodology for multiple large-area imaging using scanning electron microscopy through automated acquisition and stitching from polished thin-sections and ion-milled samples. The process is fast, efficient and minimises user-input and bias. It can provide reliable, quantifiable data on sediment grain size, grain orientation, pore size and porosity. Limitations include the time involved for individual runs and manual segmentation, the large amount of computer memory required, and instrument resolution at the nano-scale. This method is applied to selected samples of Quaternary muddy sediments from the Iberian margin at IODP Site 1385. The section comprises finegrained(very fine clayey silts), mixed-composition, biogenic-terrigenous hemipelagites, with a pronounced but non-regular colour cyclicity. There is a multi-tiered and diverse trace fossil assemblage of the deep-water Zoophycos ichnofacies. The sediment microstructures show small-scale heterogeneity in all properties, and an overall random fabric with secondary preferred grain-alignment. These results on the fabric differ, in part, from previous studies of hemipelagic muds. Further work is underway on their comparison with other deep-water sediment facies.
基金Supported by the National Natural Science Foundation of China (No.20336020).
文摘A novel two-step procedure was used to manufacture microporous activated carbon from raw coconut shell. In this process, the raw coconut shell was （1） heated in an inert environment to temperatures between 450℃ and 850℃, and reacted with oxygen （ PO2=1.1-5.3kPa） for some time, and （2） heated again in inert environment to activation temperature（850℃） to produce an activated carbon. Activated carbons with specific surface area greater than 700m^2.g^-1 were manufactured with a yield between 24% and 28%. It was shown that the carbon had a narrow distribution of pore size, possibly less than lnm, which was calculated by a simple method based on local density function theory.
