For finding valuable systematic characters, leaf epidermis of 77 taxa, representing 12 sections of the genus Clematis and three related genera in the Ranunculaceae, were examined mainly by means of light microscop...For finding valuable systematic characters, leaf epidermis of 77 taxa, representing 12 sections of the genus Clematis and three related genera in the Ranunculaceae, were examined mainly by means of light microscopy (LM), and partially by scanning electron microscopy (SEM). It was shown that the leaf epidermal cells were usually irregular or polygonal in shape. The patterns of anticlinal walls were straight, arched or undulate. The stomatal apparatus is anomocytic and exists in abaxial epidermis of all species, and in the adaxial epidermis of some species. Under SEM observation, the leaf epidermis was often striated, seldom nearly smooth, and often with flakes attached. Evidence from leaf epidermis serves as a criterion for distinguishing the subsections in sect. Meclatis (Spach) Tamura and in sect. Fruticella Tamura. The results also support that there are several separate evolutionary processes in the genus Clematis .展开更多
Vuggy reservoirs are the most common, albeit important heterogeneous carbonate reservoirs in China. However, saturation calculations using logging data are not well developed, whereas Archie method is more common. In ...Vuggy reservoirs are the most common, albeit important heterogeneous carbonate reservoirs in China. However, saturation calculations using logging data are not well developed, whereas Archie method is more common. In this study, electrical conduction in a vuggy reservoir is theoretically analyzed to establish a new saturation equation for vuggy reservoirs. We found that vugs have a greater effect on saturation than resistivity, which causes inflection in the rock-electricity curve. Using single-variable exPeriments, we evaluated the effects of rug size, vug number, and vug distribution on the rock-electricity relation. Based on the general saturation model, a saturation equation for vuggy reservoirs is derived, and the physical significance of the equation parameters is discussed based on the seepage-electricity similarity. The equation parameters depend on the pore structure, and vugs and matrix pore size distribution. Furthermore, a method for calculating the equation parameters is proposed, which uses nuclear magnetic resonance (NMR) data to calculate the capillary pressure curve. Field application of the proposed equation and parameter derivation method shows good match between calculated and experimental results, with an average absolute error of 5.8%.展开更多
By analyzing hundreds of capillary pressure curves, the controlling factors of shape and type of capillary pressure curves are found and a novel method is presented to construct capillary pressure curves by using rese...By analyzing hundreds of capillary pressure curves, the controlling factors of shape and type of capillary pressure curves are found and a novel method is presented to construct capillary pressure curves by using reservoir permeability and a synthesized index. The accuracy of this new method is verified by mercury-injection experiments. Considering the limited quantity of capillary pressure data, a new method is developed to extract the Swanson parameter from the NMR T2 distribution and estimate reservoir permeability. Integrating with NMR total porosity, reservoir capillary pressure curves can be constructed to evaluate reservoir pore structure in the intervals with NMR log data. An in-situ example of evaluating reservoir pore structure using the capillary pressure curves by this new method is presented. The result shows that it accurately detects the change in reservoir pore structure as a function of depth.展开更多
In the current work, to predict and improve the formability of deep drawing process for steel plate cold rolled commercial grade (SPCC) sheets, three parameters including the blanking force, the die and punch comer ...In the current work, to predict and improve the formability of deep drawing process for steel plate cold rolled commercial grade (SPCC) sheets, three parameters including the blanking force, the die and punch comer radius were considered. The experimental plan according to Taguchi's orthogonal array was coupled with the finite element method (FEM) simulations. Firstly, the data from the test of stress-strain and forming limit curves were used as input into ABAQUS/Explicit finite element code to predict the failure occurrence of deep drawing process. The three parameters were then validated to establish their effects on the press formability. The optimum case found via simulation was finally confirmed through an experiment. In order to obtain the complex curve profile of cup shape after deep drawing, the anisotropic behavior of earring phenomenon was modeled and implemented into FEM. After such phenomenon was correctly predicted, an error metric compared with design curve was then measured.展开更多
The principles for the modulus method and the percentage method are established and discussed in the part following Part Ⅰ of the series papers, in which we proposed the various algorithms of the strength method and ...The principles for the modulus method and the percentage method are established and discussed in the part following Part Ⅰ of the series papers, in which we proposed the various algorithms of the strength method and the work method. The samples of Wool/PET blended fibre bundles, the method of fibre-bundle tensile tests and the typical specific stress-extension curves from the fibre bundles with different blend ratios are the same as in Part Ⅰ. It can be found that the theoretical results estimated by the modulus and percentage methods accord with the experimental values highly though the calculations of the two methods are slightly more complex than those of the strength and work methods. Especially, using the modulus method can not only avoid the influence of the error caused by the determination of the tensile curve of no fibre breaking in stretching, Y(e), but also need not to know the tensile curves of mono-component fibre bundles in certain calculation. The latter advantage of the modulus method exists in the percentage method too, but it should adopt the improved calculation of ones.展开更多
A new application of Sun ONE architecture — an online custom system for Knitted Sweaters is presented, which links sweater design, manufacturing and sales in different places to share information through the Internet...A new application of Sun ONE architecture — an online custom system for Knitted Sweaters is presented, which links sweater design, manufacturing and sales in different places to share information through the Internet.The framework and characteristics of J2EE and Sun ONE are analyzed. Having studied the requirements of the online custom system for knitted sweaters, the paper presents a detailed and original system design based on J2EE technology and Web Services. This paper also gives descriptions on how to assemble and deploy the whole system under the Sun ONE architecture.展开更多
A visible magnified and simulated nozzle was designed and installed on a winding machine according to the similarity principle of Reynolds number, to study the yarn motion track in hairiness-reducing nozzle. High-spee...A visible magnified and simulated nozzle was designed and installed on a winding machine according to the similarity principle of Reynolds number, to study the yarn motion track in hairiness-reducing nozzle. High-speed photography was used to observe the yam instantaneous motion state in the nozzle. The results show that the yarn motion track seems to be a cylindrical helix which is close to inner wall in the twisting chamber and kept the same with different technical parameters, such as diameter of the twisting chamber and jet pressure in orifices. According to simulation results and reasonable simplification, the motion track equation and the rotational equation of the yarn could be derived. The velocity of the swirl and hairiness is faster than that of the yarn balloon, so there is enough time for hairiness to be wrapped into the main body of yarn and hence the hairiness is reduced.展开更多
Vortex spinning is an innovative air-jet spinning technology with promising features.A comparison of the vortex and ring spun cotton yarns and their knitted fabric properties was provided to evaluate the latent capabi...Vortex spinning is an innovative air-jet spinning technology with promising features.A comparison of the vortex and ring spun cotton yarns and their knitted fabric properties was provided to evaluate the latent capability of the vortex spinning technology.The results show that the vortex yarn has better elongation,evenness and much less hairiness than the ring yarn.The vortex fabric is found to have better air permeability,bursting properties,and pilling resistance than the ring fabric,while the drapeability and abrasion resistance of the ring fabric are better than the vortex fabric.展开更多
Back-Propagation (BP) neural network and its modified algorithm are introduced. Two series of BP neural network models have been established to predict yarn properties and to deduce wool fiber qualities. The results f...Back-Propagation (BP) neural network and its modified algorithm are introduced. Two series of BP neural network models have been established to predict yarn properties and to deduce wool fiber qualities. The results from these two series of models have been compared with the measured values respectively, proving that the accuracy in both the prediction model and the deduction model is high. The experimental results and the corresponding analysis show that the BP neural network is an efficient technique for the quality prediction and has wide prospect in the application of worsted yarn production system.展开更多
In this work, a binary-mixed-brushes-coated (BBC) capillary with switchable protein adsorption/desorption properties was developed and applied for on-line preconcentration of proteins. Firstly, amine-terminated poly(2...In this work, a binary-mixed-brushes-coated (BBC) capillary with switchable protein adsorption/desorption properties was developed and applied for on-line preconcentration of proteins. Firstly, amine-terminated poly(2-methyl-2-oxazoline)(PMOXA-NH2) and thiolterminated poly(acrylic acid)(PAA-SH) were synthesized by using cationic ring-opening polymerization (CROP) and reversible addition fragmentation chain transfer (RAFT) polymerization, respectively. Then, the BBC capillary based on poly(2-methyl-2-oxazoline)(PMOXA) and poly(acrylic acid)(PAA) was prepared by sequentially grafting of PMOXA-NH2 and PAA-SH onto fused-silica capillary inner surface through poly(dopamine)(PDA) as an anchor. The obtained PMOXA/PAA coating formed on the capillary or capillary's raw material was characterized in terms of the thickness, surface chemical composition by using scanning electron microscope (SEM) and X-ray photoelectron spectrum (XPS). The switchable protein adsorption/desorption performance of the BBC capillary was investigated by using fluorescence microscope under di erent solutions with certain pH and ionic strength(I). The results showed that bovine serum albumin (BSA) could be adsorbed on BBC capillary at pH=5.0 (I=10^-5 mol/L), and then the adsorbed BSA could be released at pH=9.0 (I=0.1 mol/L). This switchable protein adsorption/desorption property of coated capillary was then used to preconcentrate proteins on-line for increasing the detection sensitivity of BSA in capillary electrophoresis (CE). With this method, a sensitivity enhancement factor (SEF) more than 5000 for BSA detection was obtained.展开更多
Amorphous carbon materials play a vital role in adsorbed natural gas(ANG) storage. One of the key issues in the more prevalent use of ANG is the limited adsorption capacity, which is primarily determined by the porosi...Amorphous carbon materials play a vital role in adsorbed natural gas(ANG) storage. One of the key issues in the more prevalent use of ANG is the limited adsorption capacity, which is primarily determined by the porosity and surface characteristics of porous materials. To identify suitable adsorbents, we need a reliable computational tool for pore characterization and, subsequently, quantitative prediction of the adsorption behavior. Within the framework of adsorption integral equation(AIE), the pore-size distribution(PSD) is sensitive to the adopted theoretical models and numerical algorithms through isotherm fitting. In recent years, the classical density functional theory(DFT) has emerged as a common choice to describe adsorption isotherms for AIE kernel construction. However,rarely considered is the accuracy of the mean-field approximation(MFA) commonly used in commercial software. In this work, we calibrate four versions of DFT methods with grand canonical Monte Carlo(GCMC) molecular simulation for the adsorption of CH_4 and CO_2 gas in slit pores at 298 K with the pore width varying from 0.65 to 5.00 nm and pressure from 0.2 to 2.0 MPa. It is found that a weighted-density approximation proposed by Yu(WDA-Yu) is more accurate than MFA and other non-local DFT methods. In combination with the trapezoid discretization of AIE, the WDA-Yu method provides a faithful representation of experimental data, with the accuracy and stability improved by 90.0% and 91.2%, respectively, in comparison with the corresponding results from MFA for fitting CO_2 isotherms. In particular, those distributions in the feature pore width range(FPWR)are proved more representative for the pore-size analysis. The new theoretical procedure for pore characterization has also been tested with the methane adsorption capacity in seven activated carbon samples.展开更多
The fractal model about water characteristics of solidified sediment was built according to the granular metric analysis curve of solidified dredged sediment, the measured value during the low-suction stage of the cur...The fractal model about water characteristics of solidified sediment was built according to the granular metric analysis curve of solidified dredged sediment, the measured value during the low-suction stage of the curing process was used for fitting parameters in the model to obtain the complete water characteristic curve of solidified dredged sediment. Then, the quantitative calculation model of capillary water, attached water, evaporated water and bound water was built by the water characteristic curve and from the view of quantitative angle, the paper analyzed the solidification mechanism of solidified dredged sediment. The result showed that: the model can realize the quantitative calculation about different tapes of water during the curing process, the evaporated water during the curing process mainly came from the capillary water, and the generated bound water during the curing reaction came from the attached water.展开更多
The technique of atmospheric pressure plasma is of value in textile industry.In this paper,argon(Ar)and argon/oxygen(Ar/O2)atmospheric pressure plasma were used to treat wool and ramie fibers.The structures and proper...The technique of atmospheric pressure plasma is of value in textile industry.In this paper,argon(Ar)and argon/oxygen(Ar/O2)atmospheric pressure plasma were used to treat wool and ramie fibers.The structures and properties of treated fibers were investigated by means of SEM,XPS,single fiber tensile tester and so on.The results proved that the effects of plasma treatments depended on structural characteristics of fibers to a great extent,besides conditions of plasma treatment.By atmospheric pressure plasma treatment,wool fiber had significant changes in morphology structure,surface chemical component,mechanic properties and dyeability,while ramie fiber just showed a little change.In additional,Ar/O2 plasma showed more effective action than argon.And at the beginning of treatment,plasma brought about remarkable effects,which did not increase with prolonging of treat time.展开更多
In this study,a clew-like ZnO superstructure was synthesized by a copolymer-controlled self-assembly homogeneous precipitation method. Ni was impregnated to the clew-like ZnO superstructure to obtain Ni/ZnO adsorbents...In this study,a clew-like ZnO superstructure was synthesized by a copolymer-controlled self-assembly homogeneous precipitation method. Ni was impregnated to the clew-like ZnO superstructure to obtain Ni/ZnO adsorbents.The synthesized materials were characterized by scanning electron microscopy,transmission electron microscopy,N_2 sorption,X-ray diffraction,Fourier transform infrared spectrometry,and H2-temperature programmed reduction techniques. The reactive adsorption desulfurization(RADS)performance of the adsorbents was evaluated in a fixed bed reactor using thiophene in n-octane as a model fuel. Sample Ni/ZnO-4h exhibits a remarkably high performance with a sulfur capacity of 189.1 mg S g^(-1),which is above 6 times that of the one prepared with commercial ZnO. Characterization results show that the morphology changes from micro-clews to large solid sticks with the increase of the crystallization time.The loose and open architecture of the clew-like ZnO superstructure facilitates the diffusion of reactants/products,and prevents the adsorbent particles from breakage by supplying space for the volume expansion during the RADS process. The small nanoparticles in ZnO nanostrips result in a high sulfur adsorption capacity and also favor the dispersion of Ni,leading to an excellent RADS performance.展开更多
Ancient DNA data have supported a sister relationship between woolly rhinoceros and extant Sumatran rhinoceros.This relationship has been used to explore the divergent times for the woolly rhinoceros from their relati...Ancient DNA data have supported a sister relationship between woolly rhinoceros and extant Sumatran rhinoceros.This relationship has been used to explore the divergent times for the woolly rhinoceros from their relatives.Complete and partial ancient DNA sequences of the mitochondrial cytochrome b(cyt b)gene were retrieved from bones of the late Pleistocene Coelodonta antiquitatis excavated from northern and northeastern China.The newly obtained sequences together with the European and northern Asian Coelodonta antiquitatis sequences from GenBank were used to estimate the evolutionary divergence time.Phylogenetic analyses showed the exchange of genetic information between the Chinese individuals and Coelodonta antiquitatis of north Asia,which also indicated a more recent evolutionary timescale(3.8–4.7 Ma)than previous molecular estimations(17.5–22.8 or 21–26 Ma)for woolly rhinoceros based on the fossil calibration of outgroups.This new timescale was more consistent with the fossil record of the earliest known genus Coelodonta.展开更多
In the middle of the last century,American scientists put forward the concept of capillary number and obtained the relation curve between capillary number and residual oil through experiments.They revealed that the co...In the middle of the last century,American scientists put forward the concept of capillary number and obtained the relation curve between capillary number and residual oil through experiments.They revealed that the corresponding residual oil saturation decreased with increasing of capillary number;after capillary number reached up to a limit,residual oil saturation would become stable and did not decrease.These important achievements laid a theoretical base for enhanced oil recovery with chemical flooding.On the basis of the theory,scholars developed chemical flooding numerical simulation software UTCHEM.During the numerical simulation study of combination flooding,the authors found that as the capillary number is higher than the limit capillary number,the changes of the residual oil saturation along with the capillary number differ from the classical capillary number curve.Oil displacement experiments prove that there are defects in classic capillary number experimental curve and it is necessary to mend and improve.Capillary number‘calculation’curve is obtained with a method of numerical simulation calculation and a complete description of capillary number curve is provided;On this basis,combination flooding capillary number experimental curve QL is obtained through experiments,which is different from the classical capillary curve;and based on which,an expression of corresponding combination flooding relative permeability curve QL is given and the corresponding relative permeability parameters are determined with experiments.Further oil displacement experiment research recognizes the cause of the singular changes of the capillary number curve."Combination flooding capillary number experimental curve QL"and"combination flooding relative permeability curve QL"are written in combination flooding software IMCFS,providing an effective technical support for the application of combination flooding technical research.展开更多
Morphological parameters of cracks significantly affect the hydraulic conductivity of cracked soil. A laboratory test was conducted to study the hydraulic properties of cracks. The dynamic development of cracks in soi...Morphological parameters of cracks significantly affect the hydraulic conductivity of cracked soil. A laboratory test was conducted to study the hydraulic properties of cracks. The dynamic development of cracks in soil during drying and wetting was measured in the test. Based on the test results, the relationships between the morphological parameters and the soil water content were quantified. According to the fractal model, the soil-water characteristic curve(SWCC) and permeability functions for the cracked soil were predicted based on the dynamical development process of the cracks. A crack-pore dual media model was established to simulate the ponding infiltration in the unsaturated cracked soil. The variations of the pore water pressure in different part of the fractal model are quite different due to the impact of the cracks. This result illustrates that the prediction of the hydraulic properties for the cracked soil is reasonable.展开更多
文摘For finding valuable systematic characters, leaf epidermis of 77 taxa, representing 12 sections of the genus Clematis and three related genera in the Ranunculaceae, were examined mainly by means of light microscopy (LM), and partially by scanning electron microscopy (SEM). It was shown that the leaf epidermal cells were usually irregular or polygonal in shape. The patterns of anticlinal walls were straight, arched or undulate. The stomatal apparatus is anomocytic and exists in abaxial epidermis of all species, and in the adaxial epidermis of some species. Under SEM observation, the leaf epidermis was often striated, seldom nearly smooth, and often with flakes attached. Evidence from leaf epidermis serves as a criterion for distinguishing the subsections in sect. Meclatis (Spach) Tamura and in sect. Fruticella Tamura. The results also support that there are several separate evolutionary processes in the genus Clematis .
基金supported by the National S&T Major Special Project(No.2011ZX05020-008)
文摘Vuggy reservoirs are the most common, albeit important heterogeneous carbonate reservoirs in China. However, saturation calculations using logging data are not well developed, whereas Archie method is more common. In this study, electrical conduction in a vuggy reservoir is theoretically analyzed to establish a new saturation equation for vuggy reservoirs. We found that vugs have a greater effect on saturation than resistivity, which causes inflection in the rock-electricity curve. Using single-variable exPeriments, we evaluated the effects of rug size, vug number, and vug distribution on the rock-electricity relation. Based on the general saturation model, a saturation equation for vuggy reservoirs is derived, and the physical significance of the equation parameters is discussed based on the seepage-electricity similarity. The equation parameters depend on the pore structure, and vugs and matrix pore size distribution. Furthermore, a method for calculating the equation parameters is proposed, which uses nuclear magnetic resonance (NMR) data to calculate the capillary pressure curve. Field application of the proposed equation and parameter derivation method shows good match between calculated and experimental results, with an average absolute error of 5.8%.
文摘By analyzing hundreds of capillary pressure curves, the controlling factors of shape and type of capillary pressure curves are found and a novel method is presented to construct capillary pressure curves by using reservoir permeability and a synthesized index. The accuracy of this new method is verified by mercury-injection experiments. Considering the limited quantity of capillary pressure data, a new method is developed to extract the Swanson parameter from the NMR T2 distribution and estimate reservoir permeability. Integrating with NMR total porosity, reservoir capillary pressure curves can be constructed to evaluate reservoir pore structure in the intervals with NMR log data. An in-situ example of evaluating reservoir pore structure using the capillary pressure curves by this new method is presented. The result shows that it accurately detects the change in reservoir pore structure as a function of depth.
基金Project(107.02-2013.01)supported by the Vietnam’s National Foundation for Science and Technology Development
文摘In the current work, to predict and improve the formability of deep drawing process for steel plate cold rolled commercial grade (SPCC) sheets, three parameters including the blanking force, the die and punch comer radius were considered. The experimental plan according to Taguchi's orthogonal array was coupled with the finite element method (FEM) simulations. Firstly, the data from the test of stress-strain and forming limit curves were used as input into ABAQUS/Explicit finite element code to predict the failure occurrence of deep drawing process. The three parameters were then validated to establish their effects on the press formability. The optimum case found via simulation was finally confirmed through an experiment. In order to obtain the complex curve profile of cup shape after deep drawing, the anisotropic behavior of earring phenomenon was modeled and implemented into FEM. After such phenomenon was correctly predicted, an error metric compared with design curve was then measured.
文摘The principles for the modulus method and the percentage method are established and discussed in the part following Part Ⅰ of the series papers, in which we proposed the various algorithms of the strength method and the work method. The samples of Wool/PET blended fibre bundles, the method of fibre-bundle tensile tests and the typical specific stress-extension curves from the fibre bundles with different blend ratios are the same as in Part Ⅰ. It can be found that the theoretical results estimated by the modulus and percentage methods accord with the experimental values highly though the calculations of the two methods are slightly more complex than those of the strength and work methods. Especially, using the modulus method can not only avoid the influence of the error caused by the determination of the tensile curve of no fibre breaking in stretching, Y(e), but also need not to know the tensile curves of mono-component fibre bundles in certain calculation. The latter advantage of the modulus method exists in the percentage method too, but it should adopt the improved calculation of ones.
基金the key Project of Ministry of Education of China(No01083)
文摘A new application of Sun ONE architecture — an online custom system for Knitted Sweaters is presented, which links sweater design, manufacturing and sales in different places to share information through the Internet.The framework and characteristics of J2EE and Sun ONE are analyzed. Having studied the requirements of the online custom system for knitted sweaters, the paper presents a detailed and original system design based on J2EE technology and Web Services. This paper also gives descriptions on how to assemble and deploy the whole system under the Sun ONE architecture.
基金Tianjin Science and Technology Planning Projects,China(No.04310471)
文摘A visible magnified and simulated nozzle was designed and installed on a winding machine according to the similarity principle of Reynolds number, to study the yarn motion track in hairiness-reducing nozzle. High-speed photography was used to observe the yam instantaneous motion state in the nozzle. The results show that the yarn motion track seems to be a cylindrical helix which is close to inner wall in the twisting chamber and kept the same with different technical parameters, such as diameter of the twisting chamber and jet pressure in orifices. According to simulation results and reasonable simplification, the motion track equation and the rotational equation of the yarn could be derived. The velocity of the swirl and hairiness is faster than that of the yarn balloon, so there is enough time for hairiness to be wrapped into the main body of yarn and hence the hairiness is reduced.
基金National Natural Science Foundation of China(No.51076026)Natural Science Foundation of Shanghai,China(No.12ZR1440300)the Fundamental Research Funds for the Central Universities of China
文摘Vortex spinning is an innovative air-jet spinning technology with promising features.A comparison of the vortex and ring spun cotton yarns and their knitted fabric properties was provided to evaluate the latent capability of the vortex spinning technology.The results show that the vortex yarn has better elongation,evenness and much less hairiness than the ring yarn.The vortex fabric is found to have better air permeability,bursting properties,and pilling resistance than the ring fabric,while the drapeability and abrasion resistance of the ring fabric are better than the vortex fabric.
文摘Back-Propagation (BP) neural network and its modified algorithm are introduced. Two series of BP neural network models have been established to predict yarn properties and to deduce wool fiber qualities. The results from these two series of models have been compared with the measured values respectively, proving that the accuracy in both the prediction model and the deduction model is high. The experimental results and the corresponding analysis show that the BP neural network is an efficient technique for the quality prediction and has wide prospect in the application of worsted yarn production system.
基金supported by the National Natural Science Foundation of China (No.21674102)
文摘In this work, a binary-mixed-brushes-coated (BBC) capillary with switchable protein adsorption/desorption properties was developed and applied for on-line preconcentration of proteins. Firstly, amine-terminated poly(2-methyl-2-oxazoline)(PMOXA-NH2) and thiolterminated poly(acrylic acid)(PAA-SH) were synthesized by using cationic ring-opening polymerization (CROP) and reversible addition fragmentation chain transfer (RAFT) polymerization, respectively. Then, the BBC capillary based on poly(2-methyl-2-oxazoline)(PMOXA) and poly(acrylic acid)(PAA) was prepared by sequentially grafting of PMOXA-NH2 and PAA-SH onto fused-silica capillary inner surface through poly(dopamine)(PDA) as an anchor. The obtained PMOXA/PAA coating formed on the capillary or capillary's raw material was characterized in terms of the thickness, surface chemical composition by using scanning electron microscope (SEM) and X-ray photoelectron spectrum (XPS). The switchable protein adsorption/desorption performance of the BBC capillary was investigated by using fluorescence microscope under di erent solutions with certain pH and ionic strength(I). The results showed that bovine serum albumin (BSA) could be adsorbed on BBC capillary at pH=5.0 (I=10^-5 mol/L), and then the adsorbed BSA could be released at pH=9.0 (I=0.1 mol/L). This switchable protein adsorption/desorption property of coated capillary was then used to preconcentrate proteins on-line for increasing the detection sensitivity of BSA in capillary electrophoresis (CE). With this method, a sensitivity enhancement factor (SEF) more than 5000 for BSA detection was obtained.
基金Supported by the National Sci-Tech Support Plan(2015BAD21B05)China Scholarship Council(201408320127)
文摘Amorphous carbon materials play a vital role in adsorbed natural gas(ANG) storage. One of the key issues in the more prevalent use of ANG is the limited adsorption capacity, which is primarily determined by the porosity and surface characteristics of porous materials. To identify suitable adsorbents, we need a reliable computational tool for pore characterization and, subsequently, quantitative prediction of the adsorption behavior. Within the framework of adsorption integral equation(AIE), the pore-size distribution(PSD) is sensitive to the adopted theoretical models and numerical algorithms through isotherm fitting. In recent years, the classical density functional theory(DFT) has emerged as a common choice to describe adsorption isotherms for AIE kernel construction. However,rarely considered is the accuracy of the mean-field approximation(MFA) commonly used in commercial software. In this work, we calibrate four versions of DFT methods with grand canonical Monte Carlo(GCMC) molecular simulation for the adsorption of CH_4 and CO_2 gas in slit pores at 298 K with the pore width varying from 0.65 to 5.00 nm and pressure from 0.2 to 2.0 MPa. It is found that a weighted-density approximation proposed by Yu(WDA-Yu) is more accurate than MFA and other non-local DFT methods. In combination with the trapezoid discretization of AIE, the WDA-Yu method provides a faithful representation of experimental data, with the accuracy and stability improved by 90.0% and 91.2%, respectively, in comparison with the corresponding results from MFA for fitting CO_2 isotherms. In particular, those distributions in the feature pore width range(FPWR)are proved more representative for the pore-size analysis. The new theoretical procedure for pore characterization has also been tested with the methane adsorption capacity in seven activated carbon samples.
基金Acknowledgments Foundation item: National Science Foundation of China (50808068) The Ph.D. Programs Foundation of Ministry of Education of China (200802941001).
文摘The fractal model about water characteristics of solidified sediment was built according to the granular metric analysis curve of solidified dredged sediment, the measured value during the low-suction stage of the curing process was used for fitting parameters in the model to obtain the complete water characteristic curve of solidified dredged sediment. Then, the quantitative calculation model of capillary water, attached water, evaporated water and bound water was built by the water characteristic curve and from the view of quantitative angle, the paper analyzed the solidification mechanism of solidified dredged sediment. The result showed that: the model can realize the quantitative calculation about different tapes of water during the curing process, the evaporated water during the curing process mainly came from the capillary water, and the generated bound water during the curing reaction came from the attached water.
文摘The technique of atmospheric pressure plasma is of value in textile industry.In this paper,argon(Ar)and argon/oxygen(Ar/O2)atmospheric pressure plasma were used to treat wool and ramie fibers.The structures and properties of treated fibers were investigated by means of SEM,XPS,single fiber tensile tester and so on.The results proved that the effects of plasma treatments depended on structural characteristics of fibers to a great extent,besides conditions of plasma treatment.By atmospheric pressure plasma treatment,wool fiber had significant changes in morphology structure,surface chemical component,mechanic properties and dyeability,while ramie fiber just showed a little change.In additional,Ar/O2 plasma showed more effective action than argon.And at the beginning of treatment,plasma brought about remarkable effects,which did not increase with prolonging of treat time.
基金supported by the Joint Funds of the National Natural Science Foundation of China and China National Petroleum Corporation(U1362202)the National Natural Science Foundation of China(51601223 and 21206195)+2 种基金the Fundamental Research Funds for the Central Universities(17CX05018,17CX02056 and YCX2017039)Shandong Provincial Natural Science Foundation(ZR2012BM014)the project sponsored by Scientific Research Foundation for Returned Overseas Chinese Scholars
文摘In this study,a clew-like ZnO superstructure was synthesized by a copolymer-controlled self-assembly homogeneous precipitation method. Ni was impregnated to the clew-like ZnO superstructure to obtain Ni/ZnO adsorbents.The synthesized materials were characterized by scanning electron microscopy,transmission electron microscopy,N_2 sorption,X-ray diffraction,Fourier transform infrared spectrometry,and H2-temperature programmed reduction techniques. The reactive adsorption desulfurization(RADS)performance of the adsorbents was evaluated in a fixed bed reactor using thiophene in n-octane as a model fuel. Sample Ni/ZnO-4h exhibits a remarkably high performance with a sulfur capacity of 189.1 mg S g^(-1),which is above 6 times that of the one prepared with commercial ZnO. Characterization results show that the morphology changes from micro-clews to large solid sticks with the increase of the crystallization time.The loose and open architecture of the clew-like ZnO superstructure facilitates the diffusion of reactants/products,and prevents the adsorbent particles from breakage by supplying space for the volume expansion during the RADS process. The small nanoparticles in ZnO nanostrips result in a high sulfur adsorption capacity and also favor the dispersion of Ni,leading to an excellent RADS performance.
基金Yang Hong was supported by a short term Guest Professor through the sponsorship of China University of Geosciences in Wuhansupported by National Basic Research Program of China(Grant No.2011CB808800)+1 种基金National Natural Science Foundation of China(Grant Nos.40672006,40902008)"111"Project of Chinese State Administration of Foreign Experts Affairs(Grant No.B08030)
文摘Ancient DNA data have supported a sister relationship between woolly rhinoceros and extant Sumatran rhinoceros.This relationship has been used to explore the divergent times for the woolly rhinoceros from their relatives.Complete and partial ancient DNA sequences of the mitochondrial cytochrome b(cyt b)gene were retrieved from bones of the late Pleistocene Coelodonta antiquitatis excavated from northern and northeastern China.The newly obtained sequences together with the European and northern Asian Coelodonta antiquitatis sequences from GenBank were used to estimate the evolutionary divergence time.Phylogenetic analyses showed the exchange of genetic information between the Chinese individuals and Coelodonta antiquitatis of north Asia,which also indicated a more recent evolutionary timescale(3.8–4.7 Ma)than previous molecular estimations(17.5–22.8 or 21–26 Ma)for woolly rhinoceros based on the fossil calibration of outgroups.This new timescale was more consistent with the fossil record of the earliest known genus Coelodonta.
文摘In the middle of the last century,American scientists put forward the concept of capillary number and obtained the relation curve between capillary number and residual oil through experiments.They revealed that the corresponding residual oil saturation decreased with increasing of capillary number;after capillary number reached up to a limit,residual oil saturation would become stable and did not decrease.These important achievements laid a theoretical base for enhanced oil recovery with chemical flooding.On the basis of the theory,scholars developed chemical flooding numerical simulation software UTCHEM.During the numerical simulation study of combination flooding,the authors found that as the capillary number is higher than the limit capillary number,the changes of the residual oil saturation along with the capillary number differ from the classical capillary number curve.Oil displacement experiments prove that there are defects in classic capillary number experimental curve and it is necessary to mend and improve.Capillary number‘calculation’curve is obtained with a method of numerical simulation calculation and a complete description of capillary number curve is provided;On this basis,combination flooding capillary number experimental curve QL is obtained through experiments,which is different from the classical capillary curve;and based on which,an expression of corresponding combination flooding relative permeability curve QL is given and the corresponding relative permeability parameters are determined with experiments.Further oil displacement experiment research recognizes the cause of the singular changes of the capillary number curve."Combination flooding capillary number experimental curve QL"and"combination flooding relative permeability curve QL"are written in combination flooding software IMCFS,providing an effective technical support for the application of combination flooding technical research.
基金the National Natural Science Foundation of China(No.51409149)the Science Research Key Project of Hubei Provincial Department of Education(No.D20151201)the Science Research Foundation of Yichang Science and Technology Bureau(No.A14-302-a10)
文摘Morphological parameters of cracks significantly affect the hydraulic conductivity of cracked soil. A laboratory test was conducted to study the hydraulic properties of cracks. The dynamic development of cracks in soil during drying and wetting was measured in the test. Based on the test results, the relationships between the morphological parameters and the soil water content were quantified. According to the fractal model, the soil-water characteristic curve(SWCC) and permeability functions for the cracked soil were predicted based on the dynamical development process of the cracks. A crack-pore dual media model was established to simulate the ponding infiltration in the unsaturated cracked soil. The variations of the pore water pressure in different part of the fractal model are quite different due to the impact of the cracks. This result illustrates that the prediction of the hydraulic properties for the cracked soil is reasonable.