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High-performance osmotic energy conversion requires both large ionic throughput and high ionic selectivity, which can be significantly promoted by exterior surface charges simultaneously, especially for short nanopores. Here, we investigate the enhancement of ionic diffusion by charged exterior surfaces under various conditions and explore corresponding effective charged areas. From simulations, ionic diffusion is promoted more significantly by exterior surface charges through nanopores with a shorter length, wider diameter, and larger surface charge density, or under higher salt gradients. Effective widths of the charged ring regions near nanopores are reversely proportional to the pore length and linearly dependent on the pore diameter, salt gradient, and surface charge density. Due to the important role of effective charged areas in the propagation of ionic diffusion through single nanopores to cases with porous membranes, our results may provide useful guidance to the design and fabrication of porous membranes for practical high-performance osmotic energy harvesting., 24 Pages,5 figures

Biodiesel is recognized as a powerful substitute for diesel fuel. The alcohol can be blended with diesel or biodiesel for certain property improvements. In this research, the liquid thermal conduct...

Recently, biodiesel is considered as a potential alternative fuel in internal combustion engines, because of their beneficial effects on pollution emission and engine performance. In this work, a group contribution method (GCM) to predict the thermal conductivity of fatty acid methyl esters (FAMEs) and fatty acid ethyl esters (FAEEs) components of biodiesel as a function of the temperature (290 K to 350 K) is presented. Nearly 120 experimental thermal conductivity data points at different temperatures compiled for nine esters (methyl hexanoate, methyl octanoate, methyl pelargonate, methyl decanoate, ethyl valerate, ethyl valerate, ethyl heptanoate, ethyl octanoate, ethyl decanoate) were used for presenting and optimizing the formula. Additionaly, 51 experimental data points compiled for four esters (methyl myristate, methyl laurate, ethyl myristate and ethyl laurate) were employed to validate the model parameters, and the maximum and average absolute deviation are 0.61% and 1.97%. It is evident that the new proposed GCM models to predict the thermal conductivity of FAMEs and FAEEs are with high accuracy.

Thermal conductivity is a very important transport property of fluids. In this work, the liquid thermal conductivity of five aliphatic esters (ethyl acetate, ethyl propionate, ethyl butyrate, ethyl pentanoate and ethyl hexanoate) were measured by transient hot wire method at atmospheric pressure and with temperature range (249.13 to 348.46) K, (263.55 to 356.28) K, (268.57 to 363.52) K, (249.21 to 363.57) K, (254.29 to 383.37) K, respectively. It was estimated that the total relative standard uncertainty of the experimental results was smaller than 2 % (in the 95 % confidence level) and repeatability was better than ± 0.5 %. The liquid thermal conductivity results of the five esters were fitted as a polynomial function of temperature. The mean deviation and the maximum deviation of the fitted function from the experimental data of the five esters were 0.15 % and 0.36 % for ethyl acetate, 0.15 % and 0.42 % for ethyl propionate, 0.21 % and -0.41 % for ethyl butyrate, 0.21 % and -0.42 % for ethyl pentanoate, 0.32 % and -0.69 % for ethyl hexanoate, respectively.

It is well known that surface tension is dependent on temperature, and thus a nonuniform temperature may cause thermocapillary flow which is referred to as the Marangoni effect. For a thin liquid-air film confined between a flat hot plate and a topographical cold template, it undergoes deformation due to thermocapillary flow. This phenomenon is termed as thermocapillary patterning, and has been used to fabricate micro- and nanostructure in polymer films. In most cases, the obtained structure conforms to the template; i.e., it can be considered as a replication technique. In this paper, we developed a two-phase flow numerical model based on the phase field to study the dynamic process of thermocapillary patterning. As a remeshing-free method, the phase field enables the incorporation of thermal field and multiphase flow with free surface deformation. The numerical model was employed to study the dynamic process of thermocapillary patterning. Meanwhile, the effects of some parameters, e.g., temperature, geometry parameters, and contact angle, were also investigated.

The research on energy conversion and transportation of fuels at a microscopic level is of great significance to the development of industry. As a new alternative fuel, alcohols are widely used in industry and daily life, so it is necessary to investigate the thermophysical properties of them. In this work, seven species of pure liquid alcohols were performed to investigate the microscopic mechanisms of thermal energy transfer by non-equilibrium molecular dynamic (NEMD) method. Firstly, the thermal conductivity of alcohols was calculated and was found to be consistent with the experimental data. Then, the influence of temperature on energy transfer is investigated, the results show that the contribution of convection energy transfer increases and both the inter- and intramolecular terms decrease with the increase of temperature. Finally, the influence of molecular length on energy transfer was investigated at the same temperature, and it is concluded that the contribution of the convective term decreases and the interactive term increases to the total heat flux with increasing the length of the chain. It is worth mentioning that the contribution of intramolecular energy transfer gradually becomes a dominant part of the total energy transfer as the linear chain molecule increases to a certain length and the number of carbon atoms at the intersection point of inter- and intramolecular energy transfer is similar to the turning point of thermal conductivity.

It is well known that thermal field would cause instability on a two-fluid interface due to the Marangoni effect. This phenomenon is also referred to as thermocapillary flow. A thin liquid/air film experiences thermocapillary instability when it is confined between hot and cold plates. The periodic micro/nano-patterns can generally be observed in the film. Therefore, the thermocapillary instability can be used to fabricate micro/nano-polymeric structures. The present paper proposes a fully nonlinear numerical model based on the phase field method to study the dynamic process of thermocapillary instability. Interfacial evolution and nonlinear effects of the thin liquid film are especially investigated. The impact of the key parameters, e.g., the Marangoni and Reynolds numbers, on the stability are also explored. In addition to the single-mode analysis, the thermocapillary instability is also studied in the multi-mode condition. The conventional single-mode approach facilitates the stability analysis of different wavelengths, while the multi-mode method describes the experiments in a more practical way.

Thermocapillary patterning, namely, the formation of micro/nano patterns in a liquid film by surface deformation induced by an imposed thermal gradient, has enjoyed widespread applications in engineering. In this paper, we present the development of analytical and numerical models and model analyses to predict the equilibrium states of a deformed liquid polymer film under the action of thermocapillary forces. The deformation is found to be dependent on a non-dimensional parameter , there exist multiple (three at the maximum) equilibrium states. The Lyapunov energy analysis of these states reveals that one equilibrium state is stable, another is metastable and the third one is unstable.

Compared with traditional aqueous solutions, ionic liquids have important application prospects in the field of wetting and electrowetting due to the advantages of high electric conductivity, long liquid range, and low volatility. In this paper, molecular dynamics method was employed to investigate the wetting and electrowetting behaviors of the nanodroplet of ionic liquid on a solid substrate, as well as the distribution of ionic groups. The ionic liquid is 1-butyl-3-methyl tetra-fluoroborate and coarse grained to simplify the molecular simulation model. The results show that the anion and cation groups are distributed in layers above the wall, and the peaks are different corresponding to different ionic groups. Due to the attraction of the solid substrate and the electrostatic force between anions and cations, the contact angle tends to increase slightly with the increase of ionic liquid pairs. To investigate the electrowetting behaviors of ionic liquid droplet, several electric fields of different strengths and directions have been applied to the system, respectively. The results show that the static contact angles decrease obviously with the increase of electric field, and the ionic liquid droplet wets the solid surface asymmetrically under electric fields in positive and negative directions due to different diffusion abilities of cationic and anionic coarse particles. However, for a hydrophilic surface (e = 2.0 kcal/mol), the ionic liquid droplet wets symmetrically under the electric field E = ±0.18 V/A because of the strong interaction from the solid surface. Thus, the wetting and electrowetting behaviors are determined by the combine effect of electric field, interaction among cationic/anionic coarse particles, and solid substrates.

As renewable clean bio-fuels, furan fuels, which are usually named the second generation biodiesel, have attracted the extensive attention from the academic world. This work, the experiment research on the thermal conductivity of three furan fuels (Tetrahydrofuran, 2-Methylfuran, 2,5-Dimethylfuran) in the liquid phase has been completed, and the experimental thermal conductivity data of three chemicals are reported under the pressure up to 15 MPa for the first time. The experimental results had a combined expanded uncertainty of better than ± 2.0 % (in the 0.95 confidence level).

The utilization of biodiesel, which is considered as a renewable, biodegradable and clean-burning transportation fuel consisting of fatty acid alkyl esters, is a promising way to replace fossil fuels. Thermal conductivity is a very important thermophysical property of the biodiesel. In this work, the liquid thermal conductivity of five saturated fatty acid ethyl esters (ethyl myristate, ethyl laurate, ethyl caprate, ethyl caprylate and ethyl heptanoate) were measured with the temperature ranging within (290.64–393.88) K, (274.73–400.08) K, (270.00–400.44) K, (254.76–400.37) K, (250.38–393.46) K, respectively. The total relative standard uncertainty of the experimental results was estimated to be less than 2% and repeatability was better than ±0.5%. The experimental results of each substance were fitted as a function of temperature. The average absolute relative deviation and maximum absolute relative deviation between the experimental data and calculated results were 0.19% and 0.36% for ethyl myristate, 0.15% and 0.54% for ethyl laurate, 0.17% and 0.38% for ethyl caprate, 0.23% and 0.66% for ethyl caprylate, 0.19% and 0.52% for ethyl heptanoate, respectively.

The utilization of biodiesel is a promising way to replace fossil fuels, and thermal conductivity of biodiesel is a very important thermophysical property for its applications. In this work, the transient hot-wire instrument with one bare platinum wire was used to measure the thermal conductivity of five pure components of biodiesel in liquid phase at atmospheric pressure. The measured substances include methyl butyrate, methyl pentanoate, methyl caproate, methyl caprylate, and methyl pelargonate, and the temperature range was from (283 to 358) K, (285 to 362) K, (263 to 368) K, (273 to 393) K, (278 to 383) K, respectively. The total standard uncertainty of the experimental results was estimated to be less than 2% and the repeatability was better than ±0.5%. The thermal conductivity data of each substance were fitted as a function of temperature. The average absolute relative deviation and maximum absolute relative deviation between the experimental data and calculated results were 0.17% and 0.44% for methyl butyrate, 0.25% and 0.58% for methyl pentanoate, 0.16% and 0.44% for methyl caproate, 0.15% and 0.47% for methyl caprylate, 0.15% and 0.33% for methyl pelargonate, respectively.

One of the attempts to reduce the consumption of fossil fuels is to replace them with renewable and clean fuels. Among these fuels, biodiesel has been considered as a promising alternative to petroleum diesel fuel. Thermal conductivity of biodiesel is a very important thermophysical property for its applications. In this work, the liquid thermal conductivity of three saturated fatty acid methyl esters (methyl myristate, methyl laurate and methyl caprate), usually the significant biodiesel components, was measured with the temperature ranging within (304–402) K, (283–402) K, (267–400) K, respectively. The total standard uncertainty of the experimental results was estimated to be less than 2% and the repeatability was better than ± 0.5%. The thermal conductivity data of each substance were fitted as a function of temperature, and the average absolute relative deviation and maximum absolute relative deviation between the experimental data and calculated results were 0.13% and 0.44% for methyl myristate, 0.21% and 0.53% for methyl laurate, 0.28% and 0.80% for methyl caprate, respectively.

Organic Rankine Cycle (ORC) has been proven to be a promising solution to recover low-grade waste heat so as to improve the total energy efficiency. As one of the most important thermodynamic properties, vaporization heat has significant effect on the organic working fluid selection which considerably impacts the system efficiency, operation and environmental impact. In this paper, a simple new vaporization heat correlation is presented based on the corresponding states principle. This new proposed equation is valid throughout a large temperature range for all kinds of working fluids of different kinds used in ORC and could reproduce data with a very high degree of accuracy. 36 working fluids, classified into the polar and the non-polar according to the molecular polarity and chemical bonds, are chosen to calculate the vaporization heat to verify the new equation. The result shows that the absolute deviations of the polar and non-polar fluids are 0.78% and 0.66% respectively. In addition, a comparison between the new correlation and previous models has been made, from which it can be drawn a conclusion that this new equation presents more attractive than the existing equations because of its higher accuracy and simple format.

Molecular dynamics simulations were applied to study the wetting properties of nanoscale droplets on a polar silica solid substrate subjected to constant and alternative electric fields with various field frequencies. Results show that the external applied electric fields have significant effects on the wetting of the nanoscale droplet on a polar solid substrate. The droplet spreads asymmetrically under the effect of the external applied field, and this asymmetry culminates to the maximum when the electric field equals to 0.45 V nm-1. For an electric field of 1.0 V nm-1, the dynamic electro-wetting process undergoes two stages even with a symmetric equilibrium spreading state. The stage A-B transition happens suddenly when molecules on the leading edge drop onto the solid surface due to the strong attraction of the solid substrate. Furthermore, under the alternative electric field with a different GHz frequency range, it was observed that the spreading asymmetry was weakened by increasing the field frequency and the nanoscale water droplet shape changes very slightly above a threshold frequency. Accompanied by the shape variation of water droplets, the molecular dipole orientations of water molecules experience a remarkable change from a random disordered distribution to an ordered profile because of the realignment of water molecules induced by electric fields. In addition, the polar solid surface has significant effects on the rearrangement of water molecules compared with a single droplet. Thus, the electro-wetting behaviors of water droplets on a silica solid surface are determined by the competing intermolecular forces among water, solid and the electric field.

As the analog of ionic liquids, deep eutectic solvents (DESs) have drawn intense attention and are considered as a novel class of green solvents. Due to their splendid advantages such as low melting points, low vapor pressure, high thermal stability, wide liquid ranges and low price. DESs have been researched for a wide range utilization in many areas. Especially they have been investigated as heat transfer fluids recently. Thermal conductivity is an important transport property that influences the convective heat transfer. Nonetheless, very limited data is available on the thermal conductivity of DESs. In this work, nine DESs were prepared by using betaine as hydrogen bond acceptor and glycerol or 1,2-propanediol as hydrogen bond donor. Then, the thermal conductivities of these DESs were measured in a large temperature range (293 to 373 K) at atmospheric pressure. The thermal conductivity measurement had a combined expanded uncertainty better than ± 2.0% (in the 0.95 confidence level).

Organ-on-a-chip has emerged as a powerful platform with widespread applications in biomedical fields. In this platform, living cells are cultured in microfluidic chips to mimic the functions of native organ units in vitro. One important step for organ-on-a-chip is to capture cells, thus some microstructures are usually integrated in the chip to trap cells when the suspension is ejected into chip. To predict and evaluate the cell capture efficiency, we developed an Euler-Lagrange numerical model to simulate the dynamic process of cell capture. In this model, the Stokes equation was employed to solve the flow field with cells considered as spherical particles. The capture efficiency was quantified in terms of the number of trapped cells and the uniformity. Employing this model, the performance of three different designed chips was studied by numerical simulations and compared with experiments. This numerical model could be used to optimize the design of organ-on-a-chip.

Recently, biodiesel is considered as a biodegradable, renewable and high-potential fuel which could be used directly in tradition internal combustion engines. Fuel’ transport properties in high pressure are required to model the process of fuel spray, atomization and combustion accurately. This work, three ethyl esters’ liquid thermal conductivity (biodiesel compounds) in the liquid phase was measured by an experiment system which is established based on a transient hot-wire method with a bare platinum hot wire. The measurements were conducted at the temperatures ranging from 292 K to 372 K and pressure up to 15 MPa. The combined expanded uncertainty of the measurement was estimated to be ±2.0% (in the 0.95 confidence level). For interpolation, the relationship between measured results with temperature and pressure were correlated as a polynomial function, and the maximum deviation of correlations were less than 0.30%.

Recently, biodiesel has received tremendous attention from a lot of scientists as a biodegradable, renewable and high-potential fuel which could be used directly or blended with diesel in internal combustion engines. The adequate thermophysics properties of fuel are required to model the process of fuel spray, atomization and combustion accurately. In this work, three fuel blends containing methyl laurate and n-undecane, n-dodecane, n-tridecane were prepared and an important transport property—liquid thermal conductivity of which were measured by the transient hot wire method system. The measurement was conducted at temperature ranging from 292 K to 362 K at atmospheric pressure with the mass fraction of methyl laurate being nearly 0.2000, 0.4000, 0.6000 and 0.8000 (by weight) in the binary mixtures. Furthermore, the relationship between the experimental results and temperature and concentration of methyl laurate were correlated as a function. The uncertainty of the experimental system is less than ±2.0%.

Globally, biofuel is considered as the largest renewable energy source to substitute the petrochemical fuel and it is thus received a great amount of attention from both developed countries and developing countries. Among all the biofuels, biodiesel is strongly recommended as a promising alternative fuel for traditional internal combustion engines. Thermal conductivity is an essential transport property of fuel, and is vital in the flow and heat transfer process. Therefore, it is necessary to conduct the research associated with fuel’s thermal conductivity. In this work, four binary fuel mixtures containing biodiesel components methyl caprate and ethyl caprate with n-undecane and n-tridecane were prepared respectively, and the liquid thermal conductivity of which were measured by the transient hot wire method system. The measurement was conducted at the temperature from 292 K to 362 K at atmospheric pressure. The experimental data reported here have an uncertainty of less than 2%. In addition, a correlation about the relationship between the liquid thermal conductivity with temperature and the esters’ concentration in different fuel blends has been correlated.

Water transport through nanoporous materials has aroused wide interest in membrane desalination, biological medicine and nanofluids, but the underlying mechanism of water filling an empty nanopore has been ignored. We performed non-equilibrium molecular dynamics (NEMD) simulations of water filling empty CNTs with lengths of 200 and 600 A and diameters ranging from 8.14 to 20.35 A, at temperatures from 280 to 360 K. It is found water molecules liberated from the bulk phase to enter the narrow CNTs need to break the hydrogen bond (HB) network and overcome an energy barrier, and these two effects together define the entrance resistance. In addition, the strong confinement induces the highly ordered water dipole distribution in the rather small CNTs, making additional contribution to the entrance resistance. In this connection, an efficient method is deduced to measure the entrance resistance. We show that the entrance resistance accounts for more than 94.9% of the total resistance including the entrance resistance and the resistance to mass transport inside the CNT. However, with increasing diameter from 8.14 to 20.35 A, the water filling flux increases by a factor of 2 due to the dramatically reduced HB breaking effect and energy barrier. Further, when increasing temperature from 280 to 360 K, the filling flux increases by three-fold in the (10,10) CNT, associated with sharply reduced entrance resistance. It is understood that the reduced lifetime of HB at the interface has overcome the effect of enhanced energy barrier, which subsequently accounts for the reduced entrance resistance when the temperature is increased.

Electric field is an effective method to manipulate droplets in micro/nano-scale, and various physical phenomena have been found due to the interaction of electric field and fluid flow. In this study, we developed a molecular dynamic model to investigate the deforming behavior of a nano-droplet in a uniform electric field. The nano-droplet was initially confined between two plates and then wetted on the lower plate (i.e., substrate) until an equilibrium state, after that a uniform electric field in vertical direction was imposed to the system. Due to the electrical force, the droplet started to deform until achieving a new equilibrium state and the dynamic process is recorded. By comparing the equilibrium state under different electric field strength, we found a deformation hysteresis phenomenon, i.e., different deformations were obtained when increasing and decreasing the electric field. To be specific, a large electric field (E = 0.57 V ·nm^-1) is needed to stretch the nano-droplet to touch the upper plate, while a relatively lower field (E = 0.40 V ·nm^-1) is adequate to keep it contacting with the plate. Accompanied by the deformation hysteresis, a distribution hysteresis of the average dipole orientations of water molecules in the nano-droplet is also found. Such a hysteresis phenomenon is caused by the electrohydrodynamic interactions between droplet and plates, and the findings of this study could enhance our understanding of droplet deformation in an electric field.

Compared with traditional aqueous solutions, ionic liquids have important application prospects in the field of wetting and electrowetting due to the advantages of high electric conductivity, long liquid range, and low volatility. In this paper, molecular dynamics method was employed to investigate the wetting and electrowetting behaviors of the nanodroplet of ionic liquid on a solid substrate, as well as the distribution of ionic groups. The ionic liquid is 1-butyl-3-methyl tetra-fluoroborate and coarse grained to simplify the molecular simulation model. The results show that the anion and cation groups are distributed in layers above the wall, and the peaks are different corresponding to different ionic groups. Due to the attraction of the solid substrate and the electrostatic force between anions and cations, the contact angle tends to increase slightly with the increase of ionic liquid pairs. To investigate the electrowetting behaviors of ionic liquid droplet, several electric fields of different strengths and directions have been applied to the system, respectively. The results show that the static contact angles decrease obviously with the increase of electric field, and the ionic liquid droplet wets the solid surface asymmetrically under electric fields in positive and negative directions due to different diffusion abilities of cationic and anionic coarse particles. However, for a hydrophilic surface (ε = 2.0 kcal/mol), the ionic liquid droplet wets symmetrically under the electric field

In order to provide the basic thermophysical property data for the research of alternative clean fuels, the liquid thermal conductivity of methyl myristate, methyl laurate and methyl caprate which are considered as the main compounds of biodiesel was reported. The measurements of three fatty acid esters, covering a temperature range from (292 to 372) K and pressure up to 15 MPa, have been performed by a transient hot-wire technique with a bare platinum hot wire. The relative uncertainty of the experimental results was estimated to be ± 2.0% (in the 0.95 confidence level). The present thermal conductivity data were correlated as a polynomial function of temperature and pressure for the purpose of interpolation.

Biodiesel which is comprising of Fatty Acid Methyl Esters (FAMEs) or Fatty Acid Ethyl Esters (FAEEs) mixtures, has attracted tremendous attention as a potential renewable and biodegradable fuel in internal combustion engines, because of their beneficial effects on pollution emission and engine performance. In this work, the liquid thermal conductivity of two binary mixtures containing a diesel compound n-dodecane + biodiesel compounds: methyl caprate and ethyl caprate was measured by means of transient hot-wire method at the teamperature range between 292 K and 362 K at atmospheric pressure. Based on the experimental data of two binary mixtures, the correction about three useful correlations which are available to calculate the liquid thermal conductivity of mixtures have been conducted.

Electric coalescence is an effective way to achieve high performance of separating small dispersed water droplets from oils. We investigated the coalescence and break-up behaviors of double conducting droplets dissolved 0.4394 M NaCl in the presence of electric field using molecular dynamic simulations. Our results provide that the critical electric field (Ec) and the corresponding conical angle for coalescence are 0.52 V/nm and 42°. Two conducting droplets are driven to approach, contact, and eventually coalescence by the electric field when the applied electric field is weaker than Ec. Nevertheless, in the presence of the electric field stronger than Ec, the partial break-up that small daughter droplets break away from their mother droplet occurs due to the exchange and neutralization of positive and negative charged ions in the connecting liquid bridge. As the electric field increases further to 0.80 V/nm or stay above, the strong electric field leads to the entire break-up process, accompanied with ion jetting before droplets contacting.

New experimental thermal conductivity values of 1-propanol, 1-butanol and 1-pentanol in the liquid phase have been reported, and the thermal conductivity of three binary mixtures (1-propanol + methyl myristate, 1-butanol + methyl myristate and 1-pentanol + methyl myristate) have been measured at atmospheric pressure and with the temperature range 292–362 K for the first time. The total standard uncertainty of the experimental results was estimated to be less than 2% (in the 0.68 confidence level) and the repeatability was better than ±0.5%. The liquid thermal conductivity results of three alcohols, 1-butanol/methyl myristate blends and 1-pentanol/methyl myristate blends were fitted as a polynomial function of temperature. In addition, three useful correlations have been optimized by the results of 1-propanol/methyl myristate blends.

Biodiesel is considered a feasible replacement for fossil fuels. Alcohols are alternative biofuels, while also playing a role as additives to improve certain properties of diesel and biodiesel. In this work, the thermal conductivity in the liquid phase of binary mixtures of methyl caprate, usually the significant biodiesel component with three higher alcohols (1-propanol, 1-butanol, and 1-pentanol), was measured, with the temperature ranging from 287 K to 358 K at atmospheric pressure. The total standard uncertainty of the experimental results was estimated at less than 2% and the repeatability was better than ±0.5%. In addition, three correlations for estimating the thermal conductivity of mixtures were fitted and improved, with the average absolute relative deviation of the three correlations less than 0.30%.

Biodiesel has been considered as one of the feasible attempts to replace the fossil fuels. Alcohols always played a role as the additives to improve the certain properties of biodiesel. In this work, the liquid thermal conductivity of binary mixtures of methyl laurate usually the significant biodiesel component with three alcohols (1-propanol, 1-butanol and 1-pentanol) was measured with the temperature ranging within 287 K to 358 K at atmospheric pressure. The total standard uncertainty of the experimental results was estimated to be less than 2% (in the 0.68 confidence level) and the repeatability was better than ±0.5%. In addition, three useful correlations for estimating the thermal conductivity of mixtures have been fitted and optimized, and the maximum deviation of three correlations were less than 1.30%.

Molecular dynamic simulations were adopted to study the wetting properties of nanoscale droplets on rough silicon solid substrate subject to perpendicular electric fields. The effect of roughness factor and electric field strength on the static and dynamic wetting behaviors of a nano-droplet on a solid surface was investigated at the molecular level. Results show that the static contact angle tends to decrease slightly and show small difference with the increase of roughness factor, while it shows an obvious increase for the ramp-shaped surface because the appearing bottom space reduces the wettability of solid surface. Additionally, under the electric field, a nano-droplet was elongated in the field direction and the equilibrium contact angle increases with the increase of electric field strength. The nano-droplet was completely stretched to be column-shaped at a threshold value of the field. Besides, accompanied by the shape variation of water droplets, the molecular dipole orientations of water molecules experience a remarkable change from a random disordered distribution to an ordered profile because of the realignment of water molecules induced by electric fields.

Electric field-induced micro-/nanopatterns in thin polymer films, sometimes referred as electrohydrodynamic patterning, is a promising technique to fabricate micro-/nanostructures. Extensive attention has been attracted because of its advantages in microcontact (easy demolding) and low cost. Although considerable work has been done on this technique, including both experimental and theoretical ones, there still appears a requirement for understanding the mechanism of electrohydrodynamic patterning. Thus, we systematically studied the effect of different parameters on electrohydrodynamic patterning with a numerical phase field model. Previous researchers usually employed lubrication approximation (i.e., long-wave approximation) to simplify the numerical model. However, this approximation would lose its validity if the structure height is on the same scale or larger than the wavelength, which occurs in most cases. Thus, we abandoned the lubrication approximation and solved the full governing equations for fluid flow and electric field. In this model, the deformation of polymer film is described by the phase field model. As to the electric field, the leaky dielectric model is adopted in which both electrical permittivity and conductivity are considered. The fluid flow together with electric field is coupled together in the framework of phase field. By this model, the effect of physical parameters, such as external voltage, template structure height, and polymer conductivity, is studied in detail. After that, the governing equations are nondimesionalized to analyze the relationship between different parameters. A dimensionless parameter, electrical Reynolds number ER, is defined, for which, a large value would simplify the electric field to perfect dielectric model and a small value leads it to steady leaky model. These findings and results may enhance our understanding of electrohydrodynamic patterning and may be a meaningful guide for experiments.

By performing molecular dynamics simulations, a GNT/CNT hybrid structure constructed via combing (6, 6) graphyne nanotube (GNT) with (6, 6) carbon nanotube (CNT) has been designed and investigated. The mechanical properties induced by the percentage of GNT, water content and electric field were examined. Calculation results reveal that the fracture strain and strength of hollow hybrid structure are remarkably smaller than that of perfect (6, 6) CNT. In addition, the Young's modulus decreases monotonously with the increase of percentage of GNT. More importantly, the tunable mechanical properties of hybrid structure can be achieved through filling with water molecules and applying an electric field along tensile direction. Specifically, increasing water content from 0.0 to 8.70 mmol g-1 in the absence of electric field could result in fracture strain and strength reducing by 15.09% and 12.87%, respectively. Besides, enhancing fracture strain and strength of water-filled hybrid structure with water content of 8.70 mmol g-1 can also be obtained with rising electric field intensity. These findings would provide a valuable theoretical basis for designing and fabricating a nanodevice with controllable mechanical performances.

A method has been developed to quantify the nitrofuran metabolites 3-amino-5-morphorinomethyl-1,3-oxazolidinone, 3-amino-oxazolidinone, 1-aminohydantoin, and semicarbazide, as well as chloramphenicol in shrimp with a single extraction procedure followed by LC-MS/MS analysis. Dynamic selected reaction monitoring with positive and negative ionization mode switching was used. The method LODs were 0.5 ng/g for the nitrofuran metabolites and 0.3 ng/g for chloramphenicol.