Effect Of Concentration Gradient Research Articles

Kinetics of voids evolution during diffusion bonding of dissimilar metals on consideration of the realistic surface morphology: Modeling and experiments

A comprehensive model for analyzing the kinetics of void evolution and shrinkage during dissimilar diffusion bonding is proposed based on the sinusoidal profile. The model incorporates atom accumulation at void tip to determine the curvature radius of void neck, and integrates the local effect of surface diffusion to quantify the contribution of surface diffusion, thus avoiding the unrealistic void evolution observed in previous models. Furthermore, the model utilizes a combined diffusion coefficient for multicomponent alloys under the effect of stress and concentration gradients, to determine the interfacial diffusion coefficient for dissimilar joints. In contrast to previous models, the current model demonstrates significant improvements in predicted accuracy, efficiently depicting the realistic void evolution and interpreting the formation of various interfacial voids, which can be applied in various bonding cases, including for the dissimilar base metals with different surface conditions. Simulation results from bonding between austenitic steel and ferritic steel with different surface roughness reveal that interfacial voids predominantly form on the side of the base metal with the rougher bonding surface. Additionally, as surface roughness decreases, the prevailing surface source diffusion and interface source diffusion mechanisms promote void evolution and shrinkage, resulting in a significant reduction of the final bonding time. To achieve a high-quality bonding joint, it's suggested to place the smoother bonding surface on the higher creep-resistant base metal, which can accelerate the void closure process.

Net escape velocity, transfer probability, and travel time distributions within a cross-ventilated room model sheltered by urban-like block array

Natural ventilation offers significant advantages, especially in terms of energy conservation. However, most published articles have focused on the ventilation flow rate to determine the average contaminant concentration, while few have examined local ventilation distributions. Therefore, isothermal steady-state Reynolds-averaged Navier–Stokes simulations were conducted to analyze the airflow and scalar concentration fields of a cross-ventilation model sheltered by buildings. Based on these fields, we generated the spatial distributions of ventilation indices, namely, the net escape velocity (NEV), point-to-point indices transfer probability (TP), and travel time (TT), to discuss the dispersion of scalars emitted from local points in a room with natural ventilation. The NEV, which indicates the direction of the scalar discharge from each cell, exhibited a distribution distinct from the advection velocity because of concentration gradient effect. Higher TPs were observed when evaluated from a contaminant source to a target point following the NEV streamlines. Meanwhile, lower TTs were observed when evaluated in a point near the source and also from a contaminant source to a target point following the NEV streamlines. Although TP and TT are independent ventilation indices, a negative correlation between them was observed. Instead of the ventilation flow rate, the detailed structure of scalar dispersion can now be described by simultaneously analyzing the ventilation efficiency indices, which provide information on the general contaminant transport direction, and the probability and duration of transfer from a source to a target point. This potentially helps in the design of ventilation system especially in room lay-out to avoid cross-contamination.

Concentration gradient effect in liquid thermoelectric device composed of organic-solvent-added aqueous solution containing K4[Fe(CN)6]/K3[Fe(CN)6

A liquid thermoelectric conversion device (LTE), which has a simple device structure composed of low-cost materials, is attracting attention. Here, we investigated the additive effect of methanol (MeOH), acetone, and tetrahydrofuran (THF) on an LTE composed of a K4[Fe(CN)6]/K3[Fe(CN)6] aqueous solution. We ascribed to the enhancement of the thermal voltage V and electrochemical Seebeck coefficient α to precipitation of K4[Fe(CN)6] and resultant concentration gradient of [Fe(CN)6]3− between the hot and cold electrodes. The enhancement of V and α is quantitatively reproduced by the concentration gradient model incorporating experimentally-obtained solubility s(T) of K4[Fe(CN)6]. We further demonstrated that precipitation enhances the maximum power by as much as 152% in a MeOH-added LTE composed of 0.35 M K4[Fe(CN)6]/K3[Fe(CN)6] aqueous solution at ΔT = 10 K.

Initiating a composite membrane with a localized high iodine concentration layer based on adduct chemistry to enable highly reversible zinc-iodine flow batteries.

The issue of polyiodide crossover at an iodine cathode significantly diminishes the efficiency and practicality of aqueous zinc-iodine flow batteries (ZIFBs). To address this challenge, we have introduced a localized high iodine concentration (LHIC) coating layer onto a porous polyolefin membrane, which featured strong chemical adsorption by exploiting adduct chemistry between the iodine species and a series of low-cost oxides, e.g., MgO, CeO2, ZrO2, TiO2, and Al2O3. Leveraging the LHIC based on the potent iodine adsorption capability, the as-fabricated MgO-LHIC composite membrane effectively mitigates iodine crossover via Donnan repulsion and concentration gradient effects. At a high volumetric capacity of 17.8 Ah L-1, ZIFBs utilizing a MgO-LHIC composite membrane exhibited improved coulombic efficiency (CE) and energy efficiency (EE) of 96.3% and 68.6%, respectively, along with long-term cycling stability of 170 cycles. These results significantly outperform those of ZIFBs based on a blank polyolefin membrane (78.2%/61.9% after 60 cycles) and the widely used commercial Nafion N117 (67.8%/53.0% after 23 cycles). Even under high-temperature conditions (60 °C), the LHIC-based battery still demonstrates superior CE/EE of 95.1%/67.5% compared to those of the blank polyolefin membrane (CE/EE: 61.1%/46.8%). Our pioneering research showcases enormous prospects for developing high-efficiency and low-cost composite membranes based on adduct chemistry for large-scale energy storage applications.

SKI-349, a Sphingosine Kinases 1/2 Inhibitor, Suppresses Cell Viability, Invasion, and AKT/mTOR Signaling Pathway, and Shows Synergistic Cytotoxic Effects with Sorafenib in Hepatocellular Carcinoma.

SKI-349 is a novel sphingosine kinases (SPHK) inhibitor with anti-tumor effects. This study aimed to assess the effect of SKI-349 on cell biological behaviors, downstream pathways, and its synergistic effect with sorafenib in hepatocellular carcinoma (HCC). HCC cell lines (Huh7 and Hep3B) were treated with SKI-349 at concentrations of 1, 2, 4, or 8 μM. Then, SPHK1/2 activity, cell viability, proliferation, apoptosis, invasion, and protein expressions of phosphorylated-protein kinase B (p-AKT), AKT, phosphorylated-mammalian target of rapamycin (p-mTOR) and mTOR were detected. Combination index values of SKI-349 (0, 1, 2, 4, or 8 μM) and sorafenib (0, 2.5, 5, 10, or 20 μM) were calculated. SKI-349 decreased the relative SPHK1 and SPHK2 activity compared with blank control in a dose-dependent manner in the Huh7 and Hep3B cell lines. Meanwhile, SKI-349 reduced cell viability, 5-ethynyl-2'-deoxyuridine (EdU) positive cells, and invasive cells, while it increased apoptotic cells compared to blank control in a dose-dependent manner in Huh7 and Hep3B cell lines. Based on the western blot assay, SKI-349 decreased the ratio of p-AKT to AKT and that of p-mTOR to mTOR compared with blank control in a dose-dependent manner in the Huh7 and Hep3B cell lines. Additionally, SKI-349 combined with sorafenib declined cell viability with concentration gradient effects compared to SKI-349 sole treatment, and they had synergistic cytotoxic effects in Huh7 and Hep3B cell lines. SKI-349 suppresses SPHK1 and SPHK2 activity, cell viability, invasion, and AKT/mTOR signaling pathway, as well as exhibits a synergistic cytotoxic effect with sorafenib in HCC.

The mechanism of a submerged aquatic plant to various size of micro-nano plastics stress in ecological constructed wetland

Wetlands are the most self-purifying ecosystems in nature and are known as the kidneys of the Earth. The widespread use of plastic products has led to the storage of large amounts of microplastics that can negatively affect wetland plants. This of great concern owing to their refractory degradation and widespread presence in various environmental media. Current research focused on the effects of microplastic concentration gradients and ignored the potential effects of particle size differences. This study investigated the physiological responses of Vallisneria natans (V. natans) to polyethylene microplastics (PE-MPs) of different sizes. Microplastics of different particle sizes exhibit direct and indirect toxicity in V. natans. The uptake of nitrogenous substances by V. natans did not significantly differ among PE-MPs of different sizes. The V. natans had increased chlorophyll content following short-term exposure to 50 nm and 500 nm polyethylene that disappeared after 28 d of continuous exposure. The leaf antioxidant defense system is activated by PE-MP pollution stress, and oxidative stress becomes more pronounced as the particle size decreases. Moreover, the presence of PS-MPs changed the abundance of dominant microbial species in the environment but did not change the composition of the microbial community. PE-MPs caused changes in the dominant microbial communities and increased metabolic activities related to amino acid transport, energy metabolism, and signaling. This study provides a theoretical reference to utilize submerged plants in wetland restoration.

Dramatic mitigation of capacity decay and volume variation in vanadium redox flow batteries through modified preparation of electrolytes

Electrolyte imbalance caused by the undesired vanadium-ions cross-over and water transport through the membrane is one of the main critical issues of vanadium redox flow batteries, leading to battery capacity loss and electrolytes volume variation. In this work, the evolution of discharged capacity and electrolyte volume variation were firstly investigated adopting commercial electrolyte for hundreds of charge-discharge cycles in vanadium redox flow batteries employing different membranes, varying thickness and equivalent weight. Subsequently, with the support of a 1D physics-based model, the origin of the main phenomena regulating capacity decay and volume variation has been identified and different modifications in the preparation of electrolytes have been proposed. Electrolytes characterized by an equal proton concentration between the two tanks at the beginning of cycling operation turned out to limit capacity decay, while increasing electrolyte proton concentration was effective also in the mitigation of volume variation. The most promising electrolyte preparation combined the effect of high proton concentration and null osmotic pressure gradient between the two tanks: compared to commercial electrolyte this preparation reduced the capacity decay from 47.7% to 20.9%, increased the coulombic efficiency from 96.2% to 98.9% and the energy one from 79.9% to 83.4%, and also implied a negligible volume variation during cycles. The effectiveness of this electrolyte preparation has been verified with different membranes, increasing the range of validity of the results, that could be thus applied in a real system regardless of the adopted membrane.

Effects of transverse concentration gradients on the vented explosion of methane-air mixtures

Experiments were performed in a 90-L vessel with a side vent to investigate the effects of transverse concentration gradients on the vented explosion of non-uniform methane-air mixture. Controlled by a mass flow meter, methane was injected uniformly into the vessel through 18 nozzles that are evenly distributed at the top to configure a methane-air mixture with an average methane volume fraction of 10.9%. Various transverse concentration gradients were obtained by altering the free diffusion time of the methane in the vessel. The deflagration flame was recorded through a high-speed camera at a frequency of 1000 Hz, and the internal overpressure at different locations was captured through three piezoelectric sensors. Experimental results reveal that larger concentration gradient resulted in lower flame propagation rate, longer time for the burst of the vent cover, and stronger pressure oscillations. Concentration gradient affects the typical flame structure, especially the formation and development of the tulip flame. Under the present experimental conditions, Helmholtz oscillations occurred in all tests. Concentration gradient has a negative correlation with the frequency of Helmholtz oscillations but a positive correlation with the duration of oscillations. In conclusion, the variation of concentration gradient obviously affects flame propagation and pressure evolution during vented explosions, which deserves more attention in the design of explosion protection.

Study on effect of transverse concentration gradients in pipeline on methane explosion characteristics

In this paper, we studied the effects of transverse concentration gradients on methane explosion characteristics using a fully-transparent pipeline and finally came to the following conclusions. The peak explosion overpressure changed in a waveform of “M” along different measuring points, but a set of non-equivalent concentration gradients maximized this peak value. Higher methane concentrations in the Q2 region could cause the secondary peak overpressure near the both ends of the pipe. In this process, the flame outside the pipe tends to form a near-spherical shape. However, at lower methane concentrations in the Q2 region, the secondary peak overpressure was only detected near the outlet. Its occurrence at different sites may relate to the turbulence effect heightened by concentration gradients. Besides, under the same gradient, the smallest propagation speed was measured on the right of the ignition source when the flame propagated fastest on the left, which was attributed to different inhibiting effects of reflected waves on flame propagation.

COMBINED HYDRODYNAMIC INSTABILITIES AND THEIR ROLE IN THE FORMATION OF MICRO- AND NANOSTRUCTURES OF MATERIALS UNDER PLASMA INFLUENCES

The formation of micro- and nanostructures in titanium alloys subjected to combined treatment, including exposure to heterogeneous plasma flows and subsequent modification of the surface layer by a low-energy high-current electron beam, was studied. It is established that the main mechanism for the formation of structural-phase states of the micro and nanoscale range under the influence of plasma flows created by an electric explosion of conductors is the joint manifestation of Kelvin-Helmholtz and Rayleigh-Taylor instabilities at the interface of the media. It is shown that the maximum growth rate of disturbances with acceleration of the second layer g = 5 ×109 m/s2 and a transverse velocity of 0 m/s falls on the wavelength λm = 6.76 µm. If the velocity value of the second layer is u0 = 10 m/s, then λm = 6.23 µm, and at u0 = 50 m/s ‒ λm = 1.24 μm. The mechanism of formation of micro- and nanostructures during subsequent electron beam processing is a combined thermo-evaporative, concentration- capillary and thermoelectric instability. It is shown that if the influence of the concentration gradient, thermoelectric and evaporative effects is not taken into account, the maximum value of the growth rate will be observed at a wavelength of 113 µm. Taking into account thermoelectric phenomenon leads to a decrease in the value of λm to 48 μm. It is established that at the value of the thermoelectric coefficient γ = 0.1 V/K, the maximum growth rate is observed at λm = 300 nm.

Low-strain Co-free Li-rich layered cathode with excellent voltage and capacity stability

Owing to the inherent advantages of low cost and high capacity, cobalt (Co)-free lithium (Li)-rich layered oxides have become one of the most promising cathodes for next-generation high-energy lithium-ion batteries. However, these familial cathodes suffer from serious voltage decay due to many reasons, such as oxygen release and transition metal (TM) migration, which are closely related to nanoscale strain evolution. Here, by combining the synergistic effects of surface integration, bulk doping, and concentration gradient, we successfully construct a Co-free Li-rich layered cathode with a very small volumetric strain (1.05%) between 2.0 and 4.8 V, approaching the critical value of zero strain. Various characterizations indicate that the constructed zero-strain cathode can significantly suppress the TM migration, interfacial reactions, and structural degradation including cracks, lattice defects, phase evolution, and nanovoids, leading to improved voltage stability of Co-free Li-rich layered oxides during the prolonged cycles. This work provides a strategy to eliminate the lattice strain of Li-rich layered cathodes and facilitates the up-scaled application of the as-prepared cathode materials.

Coupling model of electromigration and experimental verification – Part I: Effect of atomic concentration gradient

This paper presented integrated electromigration (EM) studies through experiment, theory, and simulation. First, extensive EM tests were performed using Blech and standard wafer-level electromigration acceleration test (SWEAT)-like structures, which were fabricated on four-inch wafers. Second, a molecular dynamics (MD) simulation-based diffusion-induced strain was incorporated into the existing coupled theory. Third, one-dimensional (1D) governing equations in terms of atomic concentration for un-passivated and passivated configurations were derived for void formation and growth, using a modified Eshelby's solution to consider the effect of passivation. Fourth, a systematic approach was established, including theoretical formulations and experimental methods, to obtain key material properties, i.e., critical atomic concentration and diffusivity. We then determined the material's properties from a specific set of experimental data, using aluminium (Al) as a carrier for demonstration. These properties were then used to predict the time to failure and void growth under various conditions. The theoretical results agreed well with the experimental data. Moreover, we theoretically determined the critical threshold products of current density and conductor length for the un-passivated and passivated configurations, respectively. Both experiment and theory showed that, in the absence of mechanical stress in un-passivated configurations, the atomic self-diffusion, which was opposite to electron wind, was significant in resisting EM development. However, when mechanical stress was present, such as in passivated configurations, stress migration played a dominant role in resisting EM development. Our numerical results showed that the current density exponent n in Black's law remained as 2 in the range of the current density greater than 0.2 MA/cm2 and rapidly approached infinity at a low level of current density.

Development of a cellular mixing model for competitive-consecutive reactions

This work presents experimental and theoretical investigations into the effects of mixing on third-order reaction kinetics in a semibatch reactor with high feed rates. Minimization of the thiourea impurity in this synthetic step constituted the main objective. The kinetic data were obtained in laboratory experiments, whereas the characteristic mixing time-constants at low stirring speeds were measured using a purposely developed asymptotic pH method in linear buffer. A general mixing model combining both mass- and heat-transfer was created using cellular automata (CA) principles, and in conjunction with the engulfment (E) model of micromixing. This new approach included the effects of concentration gradients and interacting mixing-reaction zones and predicted a significant increase of the impurity formation under low mixing conditions. The predictions were also extended to an industrial scale.

Effect of IMC Thickness on the Mechanical Properties of Microbumps

With the continuous development of electronic products towards high density and small size, the size of interconnecting solder joints also continues to decrease. Under normal service conditions, micro-solder joints will be subjected to multiple loads at the same time, which in turn will cause many reliability problems in the package structure. This paper focuses on the growth pattern of IMC (Intermetallic compounds) during hot-press bonding and analyses its effect on the shear strength and creep properties of copper pillar micro-bumps. Firstly, the solder joints with different IMC thicknesses were obtained by adjusting the bonding parameters during the thermal compression bonding process, and the growth pattern of IMC during the thermal compression bonding process was analyzed. Secondly, shear experiments were conducted on solder joints with different IMC thicknesses, and the effects of IMC on the shear strength and shear fracture mode of solder joints were analyzed. Finally, creep experiments were performed on cylinder-shaped solder joints with different IMC thicknesses under different stress conditions. The results show that throughout the bonding process, copper atoms migrate under the combined effect of temperature gradient (JTM) and concentration gradient (JCM), and IMC shows asymmetric growth, and the growth rate of IMC gradually decreases with the increase of bonding holding time. Under the same temperature conditions, the shear strength of the solder joint shows a trend of increasing and then decreasing with the increase of holding time. In addition, with the increase of IMC thickness, the shear fracture mode of solder joints changes from ductile fracture in the initial stage to tough-brittle combination fracture and finally evolves to brittle fracture. With the continuous increase of stress, the steady-state creep strain rate of all solder joints increases, and the fracture location tends to be closer to the intersection of the solder and the copper pillar from inside the solder joint. With the increase of IMC thickness, the steady-state creep strain rate of solder joints shows a trend of decreasing and then increasing.

A new heat transfer model based on non-equilibrium film theory for annular flow condensation of binary zeotropic mixtures

In recent years, zeotropic mixtures have been widely used as substitutes for pure fluids. Accordingly, their condensation properties have attracted increasing attention. However, it is a challenge to accurately describe the heat transfer performance of zeotropic mixtures in condensation, which is limited by the estimation of mixture effects, especially the mass transfer resistance therein. Focusing on this issue, the mass transfer due to the axial and radial concentration gradients in the vapor phase was considered, and a new heat transfer model for the annular flow of binary zeotropic mixtures in horizontal tubes was developed based on non-equilibrium film theory. In this model, the boiling point difference was introduced to approximate the effect of concentration gradients by combining with the vapor-liquid phase equilibrium properties of binary zeotropic mixtures. Secondly, equivalent specific heat capacities were defined for an analogy with single-phase heat transfer, which further simplifies the form of the model. The simplified model was evaluated with a consolidated database of 11 mixtures from 13 sources. The results show that the predictions of the model are in good agreement with the experimental results, with a mean absolute relative deviation (MARD) of 15.88 and 91.14% of points falling in the ±30% deviation band. Predictions were also performed for excluded data from other sources and satisfactory results were obtained with a MARD of 13.47%. Moreover, the mechanism of mixture effects is elaborated. It indicates that besides the commonly mentioned heat transfer degradation, there is also heat transfer enhancement for binary zeotropic mixtures condensation due to the opposite effects of the axial and radial concentration gradients.

Compressive failure strain of unidirectional carbon fibre composites from bending tests

One of the major difficulties in establishing material properties for composites is to obtain reliable compressive strengths either from the current direct compressive testing methods due to the stress concentration or from the indirect flexural tests due to the localised stress concentration and strain gradient effect. In the present paper, unconventional flexural tests on carbon fibre/wood sandwich and monolithic composite beams have been developed and compressive failure strains of unidirectional carbon fibre composites have been obtained with high values and low variability. The compressive strain of 1.36% obtained for the IM7/8552 material is 14% higher than the highest published value found and the variability is only 3%. Strain gradient effects on the compressive failure strain from measurements with the same stressed volume have also been quantified for the first time using the proposed carbon fibre/wood sandwich beam with various wood core depths. The increase in failure strain due to the strain gradient effect reduced with the increase of total beam thickness and approached a constant value when the beam was thicker than 20 mm.

The effects of source doping concentration and doping gradient on the ON-state current of Si nanowire TFETs

The tunnel field-effect transistor (TFET) is considered a promising next-generation transistor due to its potentially limit-breaking low subthreshold swing and better immunity against short-channel effects. However, the low ON-state current (ION) of TFETs has been a critical problem. In this work, we investigated the effects of the source doping concentration and the source doping gradient (SDG) on the ION of n-type Si gate-all-around (GAA) nanowire (NW) TFETs using an ATLAS device simulator. Unexpectedly, we found that increasing the source doping concentration does not necessarily improve ION, especially for TFETs with a large SDG. Moreover, although reducing the SDG indeed increases ION, for TFETs with low source doping concentration (e.g., 1 × 1019 cm−3), the improvement in ION by reducing the SDG becomes insignificant.

Methyl orange degradation and hydrogen production simultaneously by a reverse electrodialysis−electrocoagulation coupling system powered by salinity gradient energy

To produce hydrogen and treat dye wastewater simultaneously, a salinity gradient energy (SGE) driven reverse electrodialysis（RED）− electrocoagulation (EC) coupling system was designed and investigated experimentally. Energy conversion was achieved by means of the ionic electromigration (across the membranes) and redox reaction (on the electrodes). The iron anode electrode was electro-dissolved and releases Fe2+ (to be oxidized to Fe3+), and OH– was produced at cathode electrode, which were combined to be the flocculent. Additionally, hydrogen was produced at the cathode. Experiments were conducted to investigate the effects of electrodes (surface, material, and structure) and concentration gradients (from 10:1 to 250:1) on dye methyl orange (MO) degradation and hydrogen production. It results that the use of iron electrode as anode is significantly more efficient than the aluminum electrode for MO degradation, but inversely for hydrogen production; as for cathodes, the largest MO degradation rate and hydrogen production are achieved by means of the titanium mesh electrode and titanium plate electrode respectively. When the working current is constant at 0.25 A, the MO degradation rate and hydrogen production are both decreased with the increase of the concentration gradient. When the experiments are carried under the short-circuit current condition, the MO degradation rate reaches 98.1 % in 70 min at the concentration gradient of 50:1, and the maximum hydrogen production is 294.15 ml·h−1 at the concentration gradient of 25:1. Besides, the evolutions of the following parameters have been observed, including the current of RED stacks, pH of solution, and dissolution of electrodes.

Coupling Effects of Electrostatic Interactions and Salt Concentration Gradient in Polymer Translocation through a Nanopore: A Coarse-Grained Molecular Dynamics Simulations Study.

We study the influence of polymer pore interactions and focus on the role played by the concentration gradient of salt in the translocation of polyelectrolytes (PE) through nanopores explicitly using coarse-grained Langevin dynamics simulations. The mean translocation time is calculated by varying the applied voltage, the pH, and the salt concentration gradient. Changing the pH can alter the electrostatic interaction between the protein pore and the polyelectrolyte chain. The polymer pore interaction is weakened by the increase in the strength of the externally applied electric field that drives translocation. Additionally, the screening effect of the salt can reduce the strong charge-charge repulsion between the PE beads which can make translocation faster. The simulation results show there can be antagonistic or synergistic coupling between the salt concentration-induced screening effect and the drift force originating from the salt concentration gradient thereby affecting the translocation time. Our simulation results are explained qualitatively with free energy calculations.

Energy harvesting from charged conical nanopore with salinity and temperature gradient

• An energy harvesting system from charged conical nanopore with coupled salinity and temperature gradient is proposed. • An interesting completive mechanism between the concentration gradient and temperature gradient effect was found, which determined the output performance. • The enhancement of negative temperature difference on output power is more significant compared with positive temperature difference. • The research results provide useful information for the design and optimization of energy devices. Renewable energy has been received more attention with the increasingly serious energy crisis. In this paper, an energy harvesting system from charged conical nanopore with coupled salinity and temperature gradient is proposed. The results show that the obtained maximum power increases first and then decreases as the concentration difference increases. Particularly, the enhancement of negative temperature difference (NTD) on maximum output power and the corresponding energy conversion efficiency is more significant compared with positive temperature difference (PTD) due to the simultaneous increase of short circuit current and open circuit voltage. Besides, the maximum output power is larger when the low concentration reservoir is connected to the tip end of the conical nanopore. The obtained maximum optimal value is about 0.22 pW. In the further investigation of a temperature gradient, we found that the short circuit current, open circuit voltage, and maximum output power show the approximately linear thermal response characteristics as the temperature difference is increased. Besides, an interesting competive mechanism between the concentration gradient effect and temperature gradient effect is found, which determines the prior conical nanopore orientation. The related research results provide useful information for the design and optimization of energy devices.