As an important chemical product,propylene(C_(3)H_(6))is widely used in production of many crucial chemical products such as polypropylene.Propane(C_(3)H_(8))is introduced as an inevitable gas impurity during the naph...As an important chemical product,propylene(C_(3)H_(6))is widely used in production of many crucial chemical products such as polypropylene.Propane(C_(3)H_(8))is introduced as an inevitable gas impurity during the naphtha cracking in propylene production.At present,thermal-driven energy-intensive cryogenic distillation is the most common purification method in industry.An energy-efficient,cost-effective and environmental-friendly separation technology is required to get polymer grade C_(3)H_(6)(higher than 99.5%).In face of the increasing demand of propylene,new separation technology based on porous adsorbents is expected to be a promising alternative.In recent years,metal-organic frameworks(MOFs)have obtained attention by their high porosity,regular adjustable pore shape and pore environment and keep making breakthroughs in separation and purification of many industrial gas mixtures,and are thus considered as one of the most potential types of adsorbents.The physical properties of C_(3)H_(6)and C_(3)H_(8),such as boiling point,size and kinetic diameter,are close to each other,making their separation a challenge.Most C_(3)H_(6)/C_(3)H_(8)sieving MOFs based on narrow sieving channels that restrict the access of molecules larger than their confined entrance purify mixtures at the cost of diffusion and capacity.To improve the adsorption of MOFs based on molecular sieving,a novel‘pearl-necklace’strategy was designed,which was named for its connected channel and molecular pocket vividly,but the diffusion limitation remains unsolved.展开更多
This paper presented an investigation of particle collision and penetration using the discrete element method to understand the motion of particles and improve theoretical treatment in the sieving process. The process...This paper presented an investigation of particle collision and penetration using the discrete element method to understand the motion of particles and improve theoretical treatment in the sieving process. The process progressively was divided into looseness, stratification, collision, and penetration. Particle penetration has a direct effect on the screening performance. The penetration probability was defined, and the mathematical relationships between particle penetration and vibration parameters were established using the least squares method. To obtain the ideal penetration probability for materials the amplitude and frequency should preferably be near 3.0 mm and 25 Hz, respectively. The vibration direction angle has only a slight effect on penetration. The stage of the screening process from 0.1 to 0.7 s is the primary region for collision and penetration. This paper focused on the sieving process to more fully understand how particle collision and penetration influence the screening efficiency.展开更多
Gangue from underground separation of coal can directly be used for filling mined out areas, saving transport capacity and reducing the amount of waste polluting the environment above the ground. We introduced a struc...Gangue from underground separation of coal can directly be used for filling mined out areas, saving transport capacity and reducing the amount of waste polluting the environment above the ground. We introduced a structure and operating principle of an underground direct-impact sieving device by which a separation experiment was carried out. By means of high speed conveyer belts, coal and gangue impacted the breaking board at high speeds ranging from 6 to 14 m/s. Given the differences of hardness between coal and gangue, after selective crushing, the gangue with the higher hardness was crushed less and coal with lower hardness crushed more, which could be separated by a 50 mm sieving plate. The material above the sieving plate was disposed of as gangue and the material below as coal. The results indicate that the crush ratio below the 50 mm sieving plate increases linearly with an increase in impact velocity and decays exponentially with an increase in hardness. Employing this equipment to separate coal and gangue, the hardness of coal f should be <2. This separation device provides relatively good effect in separating coal and gangue with a relatively wide difference of hardness.展开更多
Acquiring the size gradation for particle aggregates is a common practice in the granule related industry,and mechanical sieving or screening has been the normal method. Among many drawbacks of this conventional means...Acquiring the size gradation for particle aggregates is a common practice in the granule related industry,and mechanical sieving or screening has been the normal method. Among many drawbacks of this conventional means,the major ones are time-consuming,labor-intensive,and being unable to provide real-time feedback for process control. In this letter,an optical sieving approach is introduced. The two-dimensional images are used to develop methods for inferring particle volume and sieving behavior for gradation purposes. And a combination of deterministic and probabilistic methods is described to predict the sieving behaviors of the particles and to construct the gradation curves for the aggregate sample. Comparison of the optical sieving with standard mechanical sieving shows good correlation.展开更多
The traditional standard wet sieving method uses steel sieves with aperture?0.063 mm and can only determine the particle size distribution(PSD)of gravel and sand in general soil.This paper extends the traditional meth...The traditional standard wet sieving method uses steel sieves with aperture?0.063 mm and can only determine the particle size distribution(PSD)of gravel and sand in general soil.This paper extends the traditional method and presents an extended wet sieving method.The extended method uses both the steel sieves and the nylon filter cloth sieves.The apertures of the cloth sieves are smaller than 0.063 mm and equal 0.048 mm,0.038 mm,0.014 mm,0.012 mm,0.0063 mm,0.004 mm,0.003 mm,0.002 mm,and 0.001 mm,respectively.The extended method uses five steps to separate the general soil into many material sub-groups of gravel,sand,silt and clay with known particle size ranges.The complete PSD of the general soil is then calculated from the dry masses of the individual material sub-groups.The extended method is demonstrated with a general soil of completely decomposed granite(CDG)in Hong Kong,China.The silt and clay materials with different particle size ranges are further examined,checked and verified using stereomicroscopic observation,physical and chemical property tests.The results further confirm the correctness of the extended wet sieving method.展开更多
Nanofiltration(NF)membranes as high selective separators are appealing for molecular sieving,which still remains a great challenge for the mixed dyes with same charge.In this study,cellulose acetate(CA)membranes were ...Nanofiltration(NF)membranes as high selective separators are appealing for molecular sieving,which still remains a great challenge for the mixed dyes with same charge.In this study,cellulose acetate(CA)membranes were firstly aminated by ethylene imine polymer(PEI),and then the thin film of metal organic frameworks(MOFs)were constructed onto aminated CA membrane through forward-diffusion,slow crystallization and in situ growth of Fe Co-Prussian blue(FeCo-PB)crystallization layers.The designed PB@CA composite NF membrane shows an ideal rejection for Congo red(CR)/methyl orange(MO)mixture solution,with 99.7%±0.2%for CR and 33.5%±2%for MO.In addition,the composite NF membrane demonstrated good efficiency for photocatalytic degradation of organic fouling(permeability recovery ratio was up to 92%)due to the active FeCo-PB micro-cubes.Thus,this work provides a practical strategy to prepare MOFs mediated thin film composite nanofiltration membrane for precise molecular sieving and catalytic antifouling performances.展开更多
We study the quantum molecular sieving of H2 and D2 through two nanotubes placed end-to-end. An analytic treatment, assuming that the particles have classical motion along the axis of the nanotube and are confined in ...We study the quantum molecular sieving of H2 and D2 through two nanotubes placed end-to-end. An analytic treatment, assuming that the particles have classical motion along the axis of the nanotube and are confined in a potential well in the radial direction, is considered. Using this idealistic model, and under certain conditions, it is found that this device can act as a complete sieve, allowing chemically pure deuterium to be isolated from an isotope mixture. We also consider a more realistic model of two carbon nanotubes and carry out molecular dynamics simulations using a Feynman–Hibbs potential to model the quantum effects on the dynamics of H2 and D2. Sieving is also observed in this case, but is caused by a different process.展开更多
Negatively thermo-responsive 2D membranes,which mimic the stomatal opening/closing of plants,have drawn substantial interest for tunable molecular separation processes.However,these membranes are still restricted sign...Negatively thermo-responsive 2D membranes,which mimic the stomatal opening/closing of plants,have drawn substantial interest for tunable molecular separation processes.However,these membranes are still restricted significantly on account of low water permeability and poor dynamic tunability of 2D nanochannels under temperature stimulation.Here,we present a biomimetic negatively thermo-responsive MXene membrane by covalently grafting poly(N-isopropylacrylamide)(PNIPAm)onto MXene nanosheets.The uniformly grafted PNIPAm polymer chains can enlarge the interlayer spacings for increasing water permeability while also allowing more tunability of 2D nanochannels for enhancing the capability of gradually separating multiple molecules of different sizes.As expected,the constructed membrane exhibits ultrahigh water permeance of 95.6 L m^(-2) h^(-1) bar^(-1) at 25℃,which is eight-fold higher than the state-of-the-art negatively thermoresponsive 2D membranes.Moreover,the highly temperature-tunable 2D nanochannels enable the constructed membrane to perform excellent graded molecular sieving for dye-and antibiotic-based ternary mixtures.This strategy provides new perspectives in engineering smart 2D membrane and expands the scope of temperature-responsive membranes,showing promising applications in micro/nanofluidics and molecular separation.展开更多
Aqueous sodium-ion batteries are known for poor rechargeability because of the competitive water decomposition reactions and the high electrode solubility.Improvements have been reported by saltconcentrated and organi...Aqueous sodium-ion batteries are known for poor rechargeability because of the competitive water decomposition reactions and the high electrode solubility.Improvements have been reported by saltconcentrated and organic-hybridized electrolyte designs,however,at the expense of cost and safety.Here,we report the prolonged cycling of ASIBs in routine dilute electrolytes by employing artificial electrode coatings consisting of NaX zeolite and NaOH-neutralized perfluorinated sulfonic polymer.The as-formed composite interphase exhibits a molecularsieving effect jointly played by zeolite channels and size-shrunken ionic domains in the polymer matrix,which enables high rejection of hydrated Na^(+)ions while allowing fast dehydrated Na^(+)permeance.Applying this coating to electrode surfaces expands the electrochemical window of a practically feasible 2 mol kg^(-1) sodium trifluoromethanesulfonate aqueous electrolyte to 2.70 V and affords Na_(2)MnFe(CN)_(6)//NaTi_(2)(PO_(4))_(3) full cells with an unprecedented cycling stability of 94.9%capacity retention after 200 cycles at 1 C.Combined with emerging electrolyte modifications,this molecular-sieving interphase brings amplified benefits in long-term operation of ASIBs.展开更多
Ion conductive membranes(ICMs)with highly conductive proton selectivity are of significant importance and greatly desired for energy storage devices.However,it is extremely challenging to construct fast proton-selecti...Ion conductive membranes(ICMs)with highly conductive proton selectivity are of significant importance and greatly desired for energy storage devices.However,it is extremely challenging to construct fast proton-selective transport channels in ICMs.Herein,a membrane with highly conductive proton selectivity was fabricated by incorporating porous carbon sieving nanospheres with a hollow structure(HCSNs)in a polymer matrix.Due to the precise ion sieving ability of the microporous carbon shells and the fast proton transport through their accessible internal cavities,this advanced membrane presented a proton conductivity(0.084 S·cm^(-1))superior to those of a commercial Nation 212(N212)membrane(0.033S·cm^(-1))and a pure polymer membrane(0.049 S·cm^(-1)).The corresponding proton selectivity of the membrane(6.68×10^(5) S·min·cm^(-3))was found to be enhanced by about 5.9-fold and 4.3-fold,respectively,compared with those of the N212 membrane(1.13×10^(5) S·min·cm^(-3))and the pure membrane(1.56×10^(5) S·min·cm^(-3)).Low-field nuclear magnetic resonance(LF-NMR)clearly revealed the fast protonselective transport channels enabled by the HCSNs in the polymeric membrane.The proposed membrane exhibited an outstanding energy efficiency(EE)of 84%and long-term stability over 1400 cycles with a0.065%capacity decay per cycle at 120 mA·cm^(-2) in a typical vanadium flow battery(VFB)system.展开更多
Transport channels with ultrahigh K^(+)selectivity over other ions play a crucial role for living beings,but constructing ionic channels with promising K^(+)selectivity and permeability remains a challenge.Here,an asy...Transport channels with ultrahigh K^(+)selectivity over other ions play a crucial role for living beings,but constructing ionic channels with promising K^(+)selectivity and permeability remains a challenge.Here,an asymmetric bilayer membrane based on MXene(Ti 3C2Tx)lamellar channels consisting of a recognition layer(RL)on top of an enhancement layer(EL)exhibits an amazing Matthew effect:amplification of the preferred transport of K^(+),resulting in an excellent K^(+)-separation performance.The K^(+)ion is selected by the 1-aza-18-crown-6 ether-modified RL,owing to preferential affinity energy,and then rapidly trans-ported as a hydrated ion through the EL,based on the confinement effect.Other undesired ions such as Na^(+)are hindered from entering the RL by the preferred K^(+)occupation of the crown ether.The MXene(Ti_(3)C_(2)T_(x))-based Matthew membrane presents high K^(+)-permeation rates of 0.1-0.2 mol∙m2∙h1,with a significant K^(+)/Na^(+)selectivity of 5-9.The molecular separation mechanism of the Matthew membrane is investigated deeply to explore the nature of the Matthew amplification effect on K^(+)sieving,where the precise matching of the RL and EL within the membrane governs the fast K^(+)permeation with good selectivity.The asymmetric structure of our Matthew membrane is the key to understanding the biolog-ical function of ion channels for precise and fast ion transport,which will guide us in the creation of arti-ficial ion channels or membranes.展开更多
In this paper, we give about prime numbers and Blum two theorems and one guess integers.We prove the two theorems about Blum integers.Combining the guess with the primitive non-sieving quadratic sieve,we proposed a im...In this paper, we give about prime numbers and Blum two theorems and one guess integers.We prove the two theorems about Blum integers.Combining the guess with the primitive non-sieving quadratic sieve,we proposed a improved non-sieving quadratic sieve（INQS）.In INQS,we not only reduce the times of squares and modulo n, but also imply another important conclusion,that is,we don＇t need to find the greatest common divisor of two integers as we do in PNQS.By some examples,we compare it with the primitive non-sieving quadratic sieve（PNQS）. It＇s faster to factor a integer by using improved non-sieving quadratic sieve than the primitive one.展开更多
The commercial utilization of Zn metal anodes with high plating capacity is significantly hindered by the uncontrolled growth of dendrites and associated side reactions.Herein,a robust artificial ion-sieving MXene fla...The commercial utilization of Zn metal anodes with high plating capacity is significantly hindered by the uncontrolled growth of dendrites and associated side reactions.Herein,a robust artificial ion-sieving MXene flake(MXF)-coating layer,with abundant polar terminated groups,is constructed to regulate the interfacial Zn^(2+)deposition behavior.In particular,the fragmented MXF coupled with in situ generated quantum dots not only has strong Zn affinity to homogenize electric fields but also generates numerous zincophilic sites to reduce nucleation energy,thus securing a uniform dendrite-free surface.Additionally,the porous coating layer with polar groups allows the downward diffusion of Zn^(2+)to achieve bottom-up deposition and repels the excessive free water and anions to prevent parasitic reactions.The ion-sieving effect of MXF is firmly verified in symmetric cells with high areal capacity of 10-40 mAh cm^(−2)(1.0 mA cm^(−2))and depth of discharge of 15%-60%.Therefore,the functional MXF-coated anode manifests long-term cycling with 2700 h of stable plating/stripping in Zn||Zn cell.Such rational design of MXF protective layer breaks new ground in developing high plating capacity zinc anodes for practical applications.展开更多
The objective of this study was to evaluate the use of a faeces sieving tool “Digescan” as an indicator of feed valorization, and to test the influence of feeding strategy on fecal particle size (PS) distribution an...The objective of this study was to evaluate the use of a faeces sieving tool “Digescan” as an indicator of feed valorization, and to test the influence of feeding strategy on fecal particle size (PS) distribution and weight, milk performance and the possible association between them. Data from 95 trials were used. During each trial, two periods were identified: before and during live yeast probiotic (LYP) supplementation. The LYP used at 5 g/d/cow was Saccharomyces cerevisiae (CNCM I-4407, 1010 CFU/g, Actisaf<sup>®</sup> Sc47;Phileo by Lesaffre, France). Milk yield and composition were recorded. Fecal samples were taken at the end of each period and sieved with a set of two wire-mesh screens with pore sizes of 5 mm and 2 mm under running tap water. Yeast probiotic supplementation significantly reduced (P 5 mm was accompanied by 1.2 and 0.65 kg/d decrease in MY, 2.5 and 2 kg/d decrease in ECM and 3.2 and 2.6 kg/d in FCM before and during LYP supplementation, respectively. Fecal particle distribution appears to be a practicable tool to predict influences of feeding systems on feed valorization and performance in dairy cows. Live yeast increases dairy performance and decreases the quantity of fecal particles remaining in the two sieves after rinsing.展开更多
Ultramicroporous carbon materials with precisely engineered pore structures offer a promising pathway for the challenging separation of fluorinated gases with similar physicochemical properties,such as C_(3)F_(6)(fluo...Ultramicroporous carbon materials with precisely engineered pore structures offer a promising pathway for the challenging separation of fluorinated gases with similar physicochemical properties,such as C_(3)F_(6)(fluorinated propylene)and C_(3)F_(8)(fluorinated propane).In this work,we report the synthesis of CO_(2)-activated porous carbon adsorbents derived from a precursory resin and systematically investigate their molecular sieving behavior for C_(3)F_(6)/C_(3)F_(8)mixtures.Through controlled thermal pyrolysis and stepwise CO_(2)activation,we tailored ultramicropore size distributions to selectively exclude or admit target molecules.Adsorption studies reveal that optimal CO_(2)activation yields pore sizes that enable effective separation of C_(3)F_(6)from C_(3)F_(8),achieving efficient molecular sieving due to size exclusion effects.Excessive activation,however,generates larger pores that diminish selectivity due to nonspecific affinity for both gases.The findings highlight the importance of ultramicropore control for energy-efficient separation of fluorinated hydrocarbons and provide insights for designing advanced adsorbents for industrial gas purification.展开更多
The synthesis of nanoporous materials that display a combination of molecular sieving(MS)and quantum sieving(QS)effects is still a challenging task.In this work,we have demonstrated the synthesis of a nanocaged metal...The synthesis of nanoporous materials that display a combination of molecular sieving(MS)and quantum sieving(QS)effects is still a challenging task.In this work,we have demonstrated the synthesis of a nanocaged metal–organic framework(MOF),ECUT-8,that has a dual-sieving capability.ECUT-8 afforded H_(2)/D_(2) isotope separation due to its extremely narrow window size(3.0Å),resulting in QS.Further,the framework flexibility of ECUT-8 was exploited for the separation of butane and hexane isomers due to its MS effect.Other desirable features of ECUT-8 include high thermal,water,and chemical stability,making it suitable for practical application.Herein,these results open up an avenue to design the effects of coexistence of multiple sieving in one material.展开更多
The efficient separation of acetylene(C_(2)H_(2))from carbon dioxide(CO_(2))and CnH_(4)(n=1 and 2)to manufacture high purity C_(2)H_(2)and recover other light hydrocarbons is technologically important,while posing sig...The efficient separation of acetylene(C_(2)H_(2))from carbon dioxide(CO_(2))and CnH_(4)(n=1 and 2)to manufacture high purity C_(2)H_(2)and recover other light hydrocarbons is technologically important,while posing significant challenges.Herein,we reported a new TiF62−anion(TIFSIX)pillared metal-organic framework(MOF)ZNU-5(ZNU=Zhejiang Normal University)with ultramicropores for highly selective C_(2)H_(2)capture with low adsorption heat through gate opening based molecular sieving effect.ZNU-5 takes up a large amount of C_(2)H_(2)(128.6 cm^(3)/g)at 1.0 bar and 298 K but excludes CO_(2),CH_(4),and C_(2)H_(4).Such high capacity has never been realized in MOFs with molecular sieving.The breakthrough experiments further confirmed the highly selective C_(2)H_(2)separation performance from multi-component gas mixtures.3.3,2.8,and 2.2 mmol/g of C_(2)H_(2)is captured at ZNU-5 from equimolar C_(2)H_(2)/CO_(2),C_(2)H_(2)/CO_(2)/CH_(4),and C_(2)H_(2)/CO_(2)/CH_(4)/C_(2)H_(4)mixtures,respectively.Furthermore,2.6,2.0,and 1.5 mmol/g of>98%purity C_(2)H_(2)can be recycled from the desorption process.Combining high working capacity,low adsorption heat,as well as good recyclability,ZNU-5 is promising for C_(2)H_(2)purification.展开更多
Metal-organic nanosheets(MONs)as a novel material with tunable pore structures and low mass transfer resistance,have emerged as molecular sieves for the separation of gases and liquids.In theory,they can also serve as...Metal-organic nanosheets(MONs)as a novel material with tunable pore structures and low mass transfer resistance,have emerged as molecular sieves for the separation of gases and liquids.In theory,they can also serve as ion sieves for lithium metal batteries(LMBs),realizing the high-energy and dendritic free LMBs.However,there are rarely relevant reports,because it is difficult to simultaneously balance efficient ion sieving ability,high ion passing rate and high electrochemical stability.Here,we synthesized a stable ultrathin MON[Zn_(2)(Bim)_(4)]([Zn_(2)(Bim)_(4)]Nanosheet,HBim=benzimidazolate),which can achieve both efficient lithium ion sieving ability,high lithium ion passing rate and high electrochemical stability at the same time.The separator assembled by this MON exhibits high Li^(+)transfer number of 0.81 due to the accurate lithium ion and anion/solvent separation.The battery containing such separator shows high lithium ionic conductivity of 0.74 m S cm^(-1)and low activation energy of 0.099 eV,which can be attributed to the nanometer level thickness and the ion sieving effect.What is more,we realized the application of MONs-based ion sieves in LMBs with intercalation cathodes for the first time.And the LiFePO_(4)|Li battery with as-assembled separator demonstrates improved Coulombic efficiency(>99%)and significantly extended cycling life(>1600 cycles)with 80%capacity retention.展开更多
Ordered lamellar hybrid membranes are of great interest,due to their application as functional materials,including molecular sieving,biosensors,optical devices,and drug,as well as gene deliveries,but their fabrication...Ordered lamellar hybrid membranes are of great interest,due to their application as functional materials,including molecular sieving,biosensors,optical devices,and drug,as well as gene deliveries,but their fabrication remains challenging because three critical issues regarding synthesis of regular nanosheets,interfacing,and their spatial distribution in a polymer matrix are difficult to address simultaneously.Here,we fabricated a well-defined hybrid lamellar membrane through one-pot self-assembly,whose structure consisted of alternating layers of hydrophilic hyperbranched poly(ether amine)(hPEA)and polyhedral oligomeric silsesquioxane(POSS).展开更多
With the support by the National Natural Science Foundation of China,a collaborative study by the research groups led by Prof.Fang Haiping(方海平)from Shanghai Institute of Applied Physics,Chinese Academy of Sciences,...With the support by the National Natural Science Foundation of China,a collaborative study by the research groups led by Prof.Fang Haiping(方海平)from Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Prof.Wu Minghong(吴明红)from Shanghai Applied Radiation Institute。展开更多
基金support of the National Natural Science Foundation of China(Nos.22378369 and 22205207)Major Project of Natural Science Foundation of Zhejiang Province(LD24B060001).
文摘As an important chemical product,propylene(C_(3)H_(6))is widely used in production of many crucial chemical products such as polypropylene.Propane(C_(3)H_(8))is introduced as an inevitable gas impurity during the naphtha cracking in propylene production.At present,thermal-driven energy-intensive cryogenic distillation is the most common purification method in industry.An energy-efficient,cost-effective and environmental-friendly separation technology is required to get polymer grade C_(3)H_(6)(higher than 99.5%).In face of the increasing demand of propylene,new separation technology based on porous adsorbents is expected to be a promising alternative.In recent years,metal-organic frameworks(MOFs)have obtained attention by their high porosity,regular adjustable pore shape and pore environment and keep making breakthroughs in separation and purification of many industrial gas mixtures,and are thus considered as one of the most potential types of adsorbents.The physical properties of C_(3)H_(6)and C_(3)H_(8),such as boiling point,size and kinetic diameter,are close to each other,making their separation a challenge.Most C_(3)H_(6)/C_(3)H_(8)sieving MOFs based on narrow sieving channels that restrict the access of molecules larger than their confined entrance purify mixtures at the cost of diffusion and capacity.To improve the adsorption of MOFs based on molecular sieving,a novel‘pearl-necklace’strategy was designed,which was named for its connected channel and molecular pocket vividly,but the diffusion limitation remains unsolved.
文摘This paper presented an investigation of particle collision and penetration using the discrete element method to understand the motion of particles and improve theoretical treatment in the sieving process. The process progressively was divided into looseness, stratification, collision, and penetration. Particle penetration has a direct effect on the screening performance. The penetration probability was defined, and the mathematical relationships between particle penetration and vibration parameters were established using the least squares method. To obtain the ideal penetration probability for materials the amplitude and frequency should preferably be near 3.0 mm and 25 Hz, respectively. The vibration direction angle has only a slight effect on penetration. The stage of the screening process from 0.1 to 0.7 s is the primary region for collision and penetration. This paper focused on the sieving process to more fully understand how particle collision and penetration influence the screening efficiency.
基金the Natural Science Foundation of Jiangsu Province (No.BK2009098)
文摘Gangue from underground separation of coal can directly be used for filling mined out areas, saving transport capacity and reducing the amount of waste polluting the environment above the ground. We introduced a structure and operating principle of an underground direct-impact sieving device by which a separation experiment was carried out. By means of high speed conveyer belts, coal and gangue impacted the breaking board at high speeds ranging from 6 to 14 m/s. Given the differences of hardness between coal and gangue, after selective crushing, the gangue with the higher hardness was crushed less and coal with lower hardness crushed more, which could be separated by a 50 mm sieving plate. The material above the sieving plate was disposed of as gangue and the material below as coal. The results indicate that the crush ratio below the 50 mm sieving plate increases linearly with an increase in impact velocity and decays exponentially with an increase in hardness. Employing this equipment to separate coal and gangue, the hardness of coal f should be <2. This separation device provides relatively good effect in separating coal and gangue with a relatively wide difference of hardness.
基金Ningbo Natural Science Foundation (No. 2006A610016)Foundation of National Education Ministry for Returned Overseas Students & Scholars (SRF for ROCS, SEM. No.2006699).
文摘Acquiring the size gradation for particle aggregates is a common practice in the granule related industry,and mechanical sieving or screening has been the normal method. Among many drawbacks of this conventional means,the major ones are time-consuming,labor-intensive,and being unable to provide real-time feedback for process control. In this letter,an optical sieving approach is introduced. The two-dimensional images are used to develop methods for inferring particle volume and sieving behavior for gradation purposes. And a combination of deterministic and probabilistic methods is described to predict the sieving behaviors of the particles and to construct the gradation curves for the aggregate sample. Comparison of the optical sieving with standard mechanical sieving shows good correlation.
基金The work described in this paper was partially supported by grants from the Research Grant Council of the Hong Kong Special Administrative Region,China(Project Nos.HKU 17207518 and R5037-18).
文摘The traditional standard wet sieving method uses steel sieves with aperture?0.063 mm and can only determine the particle size distribution(PSD)of gravel and sand in general soil.This paper extends the traditional method and presents an extended wet sieving method.The extended method uses both the steel sieves and the nylon filter cloth sieves.The apertures of the cloth sieves are smaller than 0.063 mm and equal 0.048 mm,0.038 mm,0.014 mm,0.012 mm,0.0063 mm,0.004 mm,0.003 mm,0.002 mm,and 0.001 mm,respectively.The extended method uses five steps to separate the general soil into many material sub-groups of gravel,sand,silt and clay with known particle size ranges.The complete PSD of the general soil is then calculated from the dry masses of the individual material sub-groups.The extended method is demonstrated with a general soil of completely decomposed granite(CDG)in Hong Kong,China.The silt and clay materials with different particle size ranges are further examined,checked and verified using stereomicroscopic observation,physical and chemical property tests.The results further confirm the correctness of the extended wet sieving method.
基金International Partnership Program of Chinese Academy of Sciences-Grand Challenges(No.181GJHZ2022038GC)Key Research and Development Program of Zhejiang Province,China(No.2021C03170)+4 种基金Ten thousand plan-high level talents special support plan of Zhejiang province,China(No.ZJWR0108020)National Natural Science Foundation of China(No.51973230)Zhejiang Provincial Natural Science Foundation of China for Distinguished Young Scholars(No.LR20E030002)“Science and Technology Innovation 2025”Major Project of Ningbo(No.2020Z105)Youth Innovation Promotion Association of Chinese Academy of Science(No.2014258).
文摘Nanofiltration(NF)membranes as high selective separators are appealing for molecular sieving,which still remains a great challenge for the mixed dyes with same charge.In this study,cellulose acetate(CA)membranes were firstly aminated by ethylene imine polymer(PEI),and then the thin film of metal organic frameworks(MOFs)were constructed onto aminated CA membrane through forward-diffusion,slow crystallization and in situ growth of Fe Co-Prussian blue(FeCo-PB)crystallization layers.The designed PB@CA composite NF membrane shows an ideal rejection for Congo red(CR)/methyl orange(MO)mixture solution,with 99.7%±0.2%for CR and 33.5%±2%for MO.In addition,the composite NF membrane demonstrated good efficiency for photocatalytic degradation of organic fouling(permeability recovery ratio was up to 92%)due to the active FeCo-PB micro-cubes.Thus,this work provides a practical strategy to prepare MOFs mediated thin film composite nanofiltration membrane for precise molecular sieving and catalytic antifouling performances.
基金the financial support provided by the Italian Institute of Technology (IIT)
文摘We study the quantum molecular sieving of H2 and D2 through two nanotubes placed end-to-end. An analytic treatment, assuming that the particles have classical motion along the axis of the nanotube and are confined in a potential well in the radial direction, is considered. Using this idealistic model, and under certain conditions, it is found that this device can act as a complete sieve, allowing chemically pure deuterium to be isolated from an isotope mixture. We also consider a more realistic model of two carbon nanotubes and carry out molecular dynamics simulations using a Feynman–Hibbs potential to model the quantum effects on the dynamics of H2 and D2. Sieving is also observed in this case, but is caused by a different process.
基金supported by the National Nature Science Foundation of China(No.22278179,U23A20688)the National Key Research and Development Program of China(2021YFB3802600)+3 种基金the Fundamental Research Funds for the Central Universities(JUSRP622035)National First-Class Discipline Program of Light Industry Technology and Engineering(LIFE2018-19)MOE&SAFEA for the 111 Project(B13025)Natural Science Foundation of Xinjiang Uygur Autonomous Region(2022D01D030).
文摘Negatively thermo-responsive 2D membranes,which mimic the stomatal opening/closing of plants,have drawn substantial interest for tunable molecular separation processes.However,these membranes are still restricted significantly on account of low water permeability and poor dynamic tunability of 2D nanochannels under temperature stimulation.Here,we present a biomimetic negatively thermo-responsive MXene membrane by covalently grafting poly(N-isopropylacrylamide)(PNIPAm)onto MXene nanosheets.The uniformly grafted PNIPAm polymer chains can enlarge the interlayer spacings for increasing water permeability while also allowing more tunability of 2D nanochannels for enhancing the capability of gradually separating multiple molecules of different sizes.As expected,the constructed membrane exhibits ultrahigh water permeance of 95.6 L m^(-2) h^(-1) bar^(-1) at 25℃,which is eight-fold higher than the state-of-the-art negatively thermoresponsive 2D membranes.Moreover,the highly temperature-tunable 2D nanochannels enable the constructed membrane to perform excellent graded molecular sieving for dye-and antibiotic-based ternary mixtures.This strategy provides new perspectives in engineering smart 2D membrane and expands the scope of temperature-responsive membranes,showing promising applications in micro/nanofluidics and molecular separation.
基金supported by the National Key R&D Program of China(Grant No.2022YFB2402604)the National Natural Science Foundation of China(21975271,22209194)+3 种基金Shandong Natural Science Foundation(ZR2020ZD07,ZR2023YQ010 and ZR2021QB106)the Taishan Scholars of Shandong Province(No.ts201511063,tsqn202211277)the Shandong Energy Institute(SEI I202127)Qingdao New Energy Shandong Laboratory(QIBEBT/SEI/QNESLS202304).
文摘Aqueous sodium-ion batteries are known for poor rechargeability because of the competitive water decomposition reactions and the high electrode solubility.Improvements have been reported by saltconcentrated and organic-hybridized electrolyte designs,however,at the expense of cost and safety.Here,we report the prolonged cycling of ASIBs in routine dilute electrolytes by employing artificial electrode coatings consisting of NaX zeolite and NaOH-neutralized perfluorinated sulfonic polymer.The as-formed composite interphase exhibits a molecularsieving effect jointly played by zeolite channels and size-shrunken ionic domains in the polymer matrix,which enables high rejection of hydrated Na^(+)ions while allowing fast dehydrated Na^(+)permeance.Applying this coating to electrode surfaces expands the electrochemical window of a practically feasible 2 mol kg^(-1) sodium trifluoromethanesulfonate aqueous electrolyte to 2.70 V and affords Na_(2)MnFe(CN)_(6)//NaTi_(2)(PO_(4))_(3) full cells with an unprecedented cycling stability of 94.9%capacity retention after 200 cycles at 1 C.Combined with emerging electrolyte modifications,this molecular-sieving interphase brings amplified benefits in long-term operation of ASIBs.
基金the support from the National Key Research and Development Program of China(2021YFB3801301)the National Natural Science Foundation of China(22075076,21908098,and 21908054)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Ion conductive membranes(ICMs)with highly conductive proton selectivity are of significant importance and greatly desired for energy storage devices.However,it is extremely challenging to construct fast proton-selective transport channels in ICMs.Herein,a membrane with highly conductive proton selectivity was fabricated by incorporating porous carbon sieving nanospheres with a hollow structure(HCSNs)in a polymer matrix.Due to the precise ion sieving ability of the microporous carbon shells and the fast proton transport through their accessible internal cavities,this advanced membrane presented a proton conductivity(0.084 S·cm^(-1))superior to those of a commercial Nation 212(N212)membrane(0.033S·cm^(-1))and a pure polymer membrane(0.049 S·cm^(-1)).The corresponding proton selectivity of the membrane(6.68×10^(5) S·min·cm^(-3))was found to be enhanced by about 5.9-fold and 4.3-fold,respectively,compared with those of the N212 membrane(1.13×10^(5) S·min·cm^(-3))and the pure membrane(1.56×10^(5) S·min·cm^(-3)).Low-field nuclear magnetic resonance(LF-NMR)clearly revealed the fast protonselective transport channels enabled by the HCSNs in the polymeric membrane.The proposed membrane exhibited an outstanding energy efficiency(EE)of 84%and long-term stability over 1400 cycles with a0.065%capacity decay per cycle at 120 mA·cm^(-2) in a typical vanadium flow battery(VFB)system.
基金support from the National Key Research and Development Program(2021YFB3802500)the National Natural Science Foundation of China(22022805 and 22078107)supported by State Key Laboratory of Pulp and Paper Engineering(2022PY04)and Fundamental Research Funds for the Central Universities(2022ZYGXZR010).
文摘Transport channels with ultrahigh K^(+)selectivity over other ions play a crucial role for living beings,but constructing ionic channels with promising K^(+)selectivity and permeability remains a challenge.Here,an asymmetric bilayer membrane based on MXene(Ti 3C2Tx)lamellar channels consisting of a recognition layer(RL)on top of an enhancement layer(EL)exhibits an amazing Matthew effect:amplification of the preferred transport of K^(+),resulting in an excellent K^(+)-separation performance.The K^(+)ion is selected by the 1-aza-18-crown-6 ether-modified RL,owing to preferential affinity energy,and then rapidly trans-ported as a hydrated ion through the EL,based on the confinement effect.Other undesired ions such as Na^(+)are hindered from entering the RL by the preferred K^(+)occupation of the crown ether.The MXene(Ti_(3)C_(2)T_(x))-based Matthew membrane presents high K^(+)-permeation rates of 0.1-0.2 mol∙m2∙h1,with a significant K^(+)/Na^(+)selectivity of 5-9.The molecular separation mechanism of the Matthew membrane is investigated deeply to explore the nature of the Matthew amplification effect on K^(+)sieving,where the precise matching of the RL and EL within the membrane governs the fast K^(+)permeation with good selectivity.The asymmetric structure of our Matthew membrane is the key to understanding the biolog-ical function of ion channels for precise and fast ion transport,which will guide us in the creation of arti-ficial ion channels or membranes.
基金Supported by the National Natural Science Founda-tion of China (60573120)
文摘In this paper, we give about prime numbers and Blum two theorems and one guess integers.We prove the two theorems about Blum integers.Combining the guess with the primitive non-sieving quadratic sieve,we proposed a improved non-sieving quadratic sieve（INQS）.In INQS,we not only reduce the times of squares and modulo n, but also imply another important conclusion,that is,we don＇t need to find the greatest common divisor of two integers as we do in PNQS.By some examples,we compare it with the primitive non-sieving quadratic sieve（PNQS）. It＇s faster to factor a integer by using improved non-sieving quadratic sieve than the primitive one.
基金Hong Kong Polytechnic University,Grant/Award Number:1-WZ1Y。
文摘The commercial utilization of Zn metal anodes with high plating capacity is significantly hindered by the uncontrolled growth of dendrites and associated side reactions.Herein,a robust artificial ion-sieving MXene flake(MXF)-coating layer,with abundant polar terminated groups,is constructed to regulate the interfacial Zn^(2+)deposition behavior.In particular,the fragmented MXF coupled with in situ generated quantum dots not only has strong Zn affinity to homogenize electric fields but also generates numerous zincophilic sites to reduce nucleation energy,thus securing a uniform dendrite-free surface.Additionally,the porous coating layer with polar groups allows the downward diffusion of Zn^(2+)to achieve bottom-up deposition and repels the excessive free water and anions to prevent parasitic reactions.The ion-sieving effect of MXF is firmly verified in symmetric cells with high areal capacity of 10-40 mAh cm^(−2)(1.0 mA cm^(−2))and depth of discharge of 15%-60%.Therefore,the functional MXF-coated anode manifests long-term cycling with 2700 h of stable plating/stripping in Zn||Zn cell.Such rational design of MXF protective layer breaks new ground in developing high plating capacity zinc anodes for practical applications.
文摘The objective of this study was to evaluate the use of a faeces sieving tool “Digescan” as an indicator of feed valorization, and to test the influence of feeding strategy on fecal particle size (PS) distribution and weight, milk performance and the possible association between them. Data from 95 trials were used. During each trial, two periods were identified: before and during live yeast probiotic (LYP) supplementation. The LYP used at 5 g/d/cow was Saccharomyces cerevisiae (CNCM I-4407, 1010 CFU/g, Actisaf<sup>®</sup> Sc47;Phileo by Lesaffre, France). Milk yield and composition were recorded. Fecal samples were taken at the end of each period and sieved with a set of two wire-mesh screens with pore sizes of 5 mm and 2 mm under running tap water. Yeast probiotic supplementation significantly reduced (P 5 mm was accompanied by 1.2 and 0.65 kg/d decrease in MY, 2.5 and 2 kg/d decrease in ECM and 3.2 and 2.6 kg/d in FCM before and during LYP supplementation, respectively. Fecal particle distribution appears to be a practicable tool to predict influences of feeding systems on feed valorization and performance in dairy cows. Live yeast increases dairy performance and decreases the quantity of fecal particles remaining in the two sieves after rinsing.
基金the National Natural Science Foundation of China(No.22225802,22208288,22421004,22141001,22288102,U24A20532)the Zhejiang Provincial Natural Science Foundation of China(No.LZ22B060002,LQ22B060005)Zhejiang Provincial Innovation Center of Advanced Chemicals Technology(2024SJCZX0020).
文摘Ultramicroporous carbon materials with precisely engineered pore structures offer a promising pathway for the challenging separation of fluorinated gases with similar physicochemical properties,such as C_(3)F_(6)(fluorinated propylene)and C_(3)F_(8)(fluorinated propane).In this work,we report the synthesis of CO_(2)-activated porous carbon adsorbents derived from a precursory resin and systematically investigate their molecular sieving behavior for C_(3)F_(6)/C_(3)F_(8)mixtures.Through controlled thermal pyrolysis and stepwise CO_(2)activation,we tailored ultramicropore size distributions to selectively exclude or admit target molecules.Adsorption studies reveal that optimal CO_(2)activation yields pore sizes that enable effective separation of C_(3)F_(6)from C_(3)F_(8),achieving efficient molecular sieving due to size exclusion effects.Excessive activation,however,generates larger pores that diminish selectivity due to nonspecific affinity for both gases.The findings highlight the importance of ultramicropore control for energy-efficient separation of fluorinated hydrocarbons and provide insights for designing advanced adsorbents for industrial gas purification.
基金supported financially by the National Natural Science Foundations of China(nos.21966002,21871047,and 21861017)the Natural Science Foundation of Jiangxi Province of China(no.20181ACB20003)the Training Program for Academic and Technical Leaders of Major Disciplines in Jiangxi Province(no.20194BCJ22010).
文摘The synthesis of nanoporous materials that display a combination of molecular sieving(MS)and quantum sieving(QS)effects is still a challenging task.In this work,we have demonstrated the synthesis of a nanocaged metal–organic framework(MOF),ECUT-8,that has a dual-sieving capability.ECUT-8 afforded H_(2)/D_(2) isotope separation due to its extremely narrow window size(3.0Å),resulting in QS.Further,the framework flexibility of ECUT-8 was exploited for the separation of butane and hexane isomers due to its MS effect.Other desirable features of ECUT-8 include high thermal,water,and chemical stability,making it suitable for practical application.Herein,these results open up an avenue to design the effects of coexistence of multiple sieving in one material.
基金support by the National Natural Science Foundation of China(No.21908193)Jinhua Industrial Key Project(No.2021A22648)+2 种基金S.D.acknowledged the financial support by the National Natural Science Foundation of China(No.21871231)the Special Funds for Basic Scientific Research of Zhejiang University(Nos.2019QNA3010 and K20210335)support by the National Natural Science Foundation of China(No.22205207).
文摘The efficient separation of acetylene(C_(2)H_(2))from carbon dioxide(CO_(2))and CnH_(4)(n=1 and 2)to manufacture high purity C_(2)H_(2)and recover other light hydrocarbons is technologically important,while posing significant challenges.Herein,we reported a new TiF62−anion(TIFSIX)pillared metal-organic framework(MOF)ZNU-5(ZNU=Zhejiang Normal University)with ultramicropores for highly selective C_(2)H_(2)capture with low adsorption heat through gate opening based molecular sieving effect.ZNU-5 takes up a large amount of C_(2)H_(2)(128.6 cm^(3)/g)at 1.0 bar and 298 K but excludes CO_(2),CH_(4),and C_(2)H_(4).Such high capacity has never been realized in MOFs with molecular sieving.The breakthrough experiments further confirmed the highly selective C_(2)H_(2)separation performance from multi-component gas mixtures.3.3,2.8,and 2.2 mmol/g of C_(2)H_(2)is captured at ZNU-5 from equimolar C_(2)H_(2)/CO_(2),C_(2)H_(2)/CO_(2)/CH_(4),and C_(2)H_(2)/CO_(2)/CH_(4)/C_(2)H_(4)mixtures,respectively.Furthermore,2.6,2.0,and 1.5 mmol/g of>98%purity C_(2)H_(2)can be recycled from the desorption process.Combining high working capacity,low adsorption heat,as well as good recyclability,ZNU-5 is promising for C_(2)H_(2)purification.
基金the financial support of the Natural Science Foundation of Shanxi Province(20210302124055)the National Natural Science Foundation of China(22301170,22271211 and 91961201)1331 Project of Shanxi Province。
文摘Metal-organic nanosheets(MONs)as a novel material with tunable pore structures and low mass transfer resistance,have emerged as molecular sieves for the separation of gases and liquids.In theory,they can also serve as ion sieves for lithium metal batteries(LMBs),realizing the high-energy and dendritic free LMBs.However,there are rarely relevant reports,because it is difficult to simultaneously balance efficient ion sieving ability,high ion passing rate and high electrochemical stability.Here,we synthesized a stable ultrathin MON[Zn_(2)(Bim)_(4)]([Zn_(2)(Bim)_(4)]Nanosheet,HBim=benzimidazolate),which can achieve both efficient lithium ion sieving ability,high lithium ion passing rate and high electrochemical stability at the same time.The separator assembled by this MON exhibits high Li^(+)transfer number of 0.81 due to the accurate lithium ion and anion/solvent separation.The battery containing such separator shows high lithium ionic conductivity of 0.74 m S cm^(-1)and low activation energy of 0.099 eV,which can be attributed to the nanometer level thickness and the ion sieving effect.What is more,we realized the application of MONs-based ion sieves in LMBs with intercalation cathodes for the first time.And the LiFePO_(4)|Li battery with as-assembled separator demonstrates improved Coulombic efficiency(>99%)and significantly extended cycling life(>1600 cycles)with 80%capacity retention.
基金the National Nature Science Foundation of China(51773114 and 21704062)Shanghai Municipal Government(17JC1400700)for their financial support.
文摘Ordered lamellar hybrid membranes are of great interest,due to their application as functional materials,including molecular sieving,biosensors,optical devices,and drug,as well as gene deliveries,but their fabrication remains challenging because three critical issues regarding synthesis of regular nanosheets,interfacing,and their spatial distribution in a polymer matrix are difficult to address simultaneously.Here,we fabricated a well-defined hybrid lamellar membrane through one-pot self-assembly,whose structure consisted of alternating layers of hydrophilic hyperbranched poly(ether amine)(hPEA)and polyhedral oligomeric silsesquioxane(POSS).
文摘With the support by the National Natural Science Foundation of China,a collaborative study by the research groups led by Prof.Fang Haiping(方海平)from Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Prof.Wu Minghong(吴明红)from Shanghai Applied Radiation Institute。
