Mechanism Of Efficiency Improvement Research Articles

P‐156: Efficiency Improvement Mechanism Analysis of Sidewall Passivation GaN based Micro‐LEDs by Atomic Layer Deposition

Sidewall passivation using atomic layer deposition (ALD) can efficiently improve external quantum efficiency (EQE). Such treatment increases EQE, a combination of internal quantum efficiency (IQE) and light extraction efficiency (LEE), primarily by curtailing surface recombination according to the ABC model. Determined by the ratio of radiative recombination rate to total recombination rate, the IQE of an LED holds a significant correlation with the diode's ideality factor in the Shockley model. In this paper, we analysis the mechanism of ALD sidewall passivation enhancing device performance in detail from the aspects of electrical performance improvement and optical performance improvement.

Efficiency Improvement and Market Value Analysis of Guide Vane Electrostatic Precipitators

Urbanization and industrialization accelerate, the issue of atmospheric environmental pollution has become increasingly severe, particularly the impact of indoor air quality on human health and well-being. This study introduces a novel guide vane electrostatic precipitator that significantly enhances dust removal efficiency through optimized airflow channels and electrostatic field design. Experimental data demonstrate that this device can effectively reduce PM2.5 concentrations, improving dust removal efficiency by approximately 10% compared to traditional electrostatic dust removal technologies. Applications in various scenarios, including hotels, dust workshops, and steel foundries, indicate that the device not only improves air quality, enhancing employee productivity and well-being, but also features low energy consumption and intelligent operation. Furthermore, it holds considerable potential market value, contributing to the promotion of green and low-carbon development objectives. This research provides a comprehensive analysis and evaluation of the structure, working principle, mechanism of efficiency improvement, practical application effects, and market value of the guide vane electrostatic precipitator, looking forward to its application prospects in the field of air purification.

Efficiency Improvement Mechanism of Smart Logistics Technology in Rural E-commerce Logistics and Distribution

Abstract This paper addresses the problems existing in the current two-way logistics and distribution model of rural e-commerce and proposes the study of rural e-commerce distribution efficiency with the technical support of intelligent logistics. Based on the knowledge of multi-objective optimization theory, the maximization of distribution efficiency of logistics enterprises and the maximization of demand coverage as the objective function, while the constraints are vehicle load, service time, path constraints, and finally, complete the construction of the multi-objective optimization model of rural e-commerce logistics and distribution efficiency. According to the NSGA-II algorithm with low computational complexity, fast operation speed, and good convergence, the NSGA-II algorithm is used to solve the constructed model, and then the optimal solution of rural e-commerce logistics distribution efficiency is derived. With regional logistics as the research subject, a multi-objective optimization model for rural e-commerce logistics distribution efficiency supported by intelligent logistics technology is simulated and analyzed. The data show that compared with other algorithms, the NSGAII algorithm has a smoother learning curve oscillation, while the final result of convergence (-1.473), the objective function is smaller (20.42), and the optimal total transportation time is smaller (609.22s). Finally, in order to solve the current rural e-commerce logistics and distribution problems in part, from the improvement of rural e-commerce logistics and distribution system, strengthen the rural logistics infrastructure construction of the two aspects of rural e-commerce logistics and distribution efficiency improvement strategy.

Analysis and research on the efficiency improvement mechanism of automated invoicing process of outage ticket based on queuing theory

Analysis and research on the efficiency improvement mechanism of automated invoicing process of outage ticket based on queuing theory

Control and Enhancement of Single-Molecule Electroluminescence through Strong Light–Matter Coupling

The energetic positions of molecular electronic states at molecule/electrode interfaces are crucial factors for determining the transport and optoelectronic properties of molecular junctions. Strong light-matter coupling offers a potential for manipulating these factors, enabling a boost in the efficiency and versatility of these junctions. Here, we investigate electroluminescence from single-molecule junctions in which the molecule is strongly coupled with the vacuum electromagnetic field in a plasmonic nanocavity. We demonstrate an improvement in the electroluminescence efficiency by employing the strong light-matter coupling in conjunction with the characteristic feature of single-molecule junctions to selectively control the formation of the lowest-energy excited state. The mechanism of efficiency improvement is discussed based on the energetic position and composition of the formed polaritonic states. Our findings indicate the possibility to manipulate optoelectronic conversion in molecular junctions by strong light-matter coupling and contribute to providing design principles for developing efficient molecular optoelectronic devices.

Advances in chloride additives for high-efficiency perovskite solar cells: multiple points of view.

Chloride (Cl) additives are rather effective in improving the performance of perovskite solar cells (PSCs) through the modulation of crystallization process and surface morphology. After incorporating Cl-containing additives, the optoelectrical properties of perovskite films, such as the electron/hole diffusion length and carrier lifetime, are greatly enhanced. However, only a trace amount of Cl has been identified in the resultant perovskite film, and the mechanism of efficiency improvement induced by Cl remains unclear. In this review, we discuss organic and inorganic Cl additives systematically from the perspective of their solubility, volatility, cation size and chemical groups. In addition, the roles of residual Cl anions and cations are analyzed in detail. Finally, some valuable future perspectives of Cl additives are proposed.

Analysis of the efficiency improvement of 273 nm AlGaN UV-C micro-LEDs

UV-C LEDs have great application prospects in the fields of sterilization, disinfection, and non-line-of-sight solar-blind communication. However, their efficiency is currently not high enough to satisfy these applications and needs to be improved. In this work, AlGaN based UV-C LEDs (273 nm) with size from 8 to 200 μm were fabricated to evaluate the size effect of external quantum efficiency (EQE). Higher EQE was detected in smaller-size UV-C micro-LEDs. Simulations on EQE were performed. The analysis on experimental data and the simulation results reveals that higher EQE originates from both higher internal quantum efficiency at high current densities due to better current spreading and higher light extraction efficiency (LEE) due to the larger proportion of sidewall. From the efficiency improvement mechanism, it is concluded that the most sever current density non-uniformity and LEE loss of UV-C devices compared with visible or near ultraviolet LEDs can be effectively restrained by preparing micro-LEDs. Our work helps to optimize the efficiency characteristics for UV-C applications.

Effects of surface tension on the dynamics of a single micro bubble near a rigid wall in an ultrasonic field

Acoustic cavitation is a very important hydrodynamic phenomenon, and is often implicated in a myriad of industrial, medical, and daily living applications. In these applications, the effect mechanism of liquid surface tension on improving the efficiency of acoustic cavitation is a crucial concern for researchers. In this study, the effects of liquid surface tension on the dynamics of an ultrasonic driven bubble near a rigid wall, which could be the main mechanism of efficiency improvement in the applications of acoustic cavitation, were investigated at the microscale level. A synchronous high-speed microscopic imaging method was used to clearly record the temporary evolution of single acoustic cavitation bubble in the liquids with different surface tension. Meanwhile, the bubble dynamic characteristics, such as the position and time of bubble collapse, the size and stability of the bubbles, the speed of bubble boundaries and the micro-jets, were analyzed and compared. In the case of the single bubbles near a rigid wall, it was found that low surface tension reduces the stability of the bubbles in the liquid medium. Meanwhile, the bubbles collapse earlier and farther from the rigid wall in the liquids with lower surface tension. In addition, the surface tension has no significant influence on the speed of the first micro-jet, but it can substantially increase the speed of second and the third micro-jets after the first collapse of the bubble. These effects of liquid surface tension on the bubble dynamics can explain the mechanism of surfactants in numerous fields of acoustic cavitation for facilitating its optimization and application.

Study on the combustion characteristics of furan- and nitromethane-added hydrocarbon fuels

In this study, the combustion characteristics of furan and nitromethane-added fuels were studied to clarify the thermal efficiency improvement mechanism in engine experiments. The laminar burning velocity was measured using a constant volume chamber. The laminar burning velocity of the furan was found to be high, but the effect of the furan addition on the laminar burning velocity was small. Alternatively, the addition of furan to S5H was found to increase the lean flammability limit, which can be related to the thermal efficiency improvement in engine experiments. In addition, extinction characteristics were evaluated for diffusion flames using a counterflow burner. Consequently, it was found that furan exhibited large resistance for flame extinction. The extinction characteristics of furan can result in an increase in the lean flammability limit of furan-containing fuel, which can improve the thermal efficiency of the engine following the addition of furan. However, nitromethane has smaller resistance for flame extinction than isooctane in terms of diffusion flames, which is considered to be a consequence of the decreased laminar burning velocity near the stoichiometric mixture of nitromethane compared with the fuel-lean scenario.

Resource recycle efficiency improvement analysis for sharing bicycles: Value chain perspective

Sharing economy represents a new business model in which the access to goods, services, spaces, and other assets can be shared or obtained. Sharing economy firms have been able to achieve global levels of success at an unprecedented space. It is acknowledged by the public and enterprises due to intensive utilization of resources. In order to help enterprises understand and clarify the resources efficiency improvement mechanism of environmental impact during the promotion of the sharing economy model in operation, this paper explores the evolutionary history and value chain of different bicycle consumption pattern, then employs a queuing theory to discuss the feasibility of the sharing bicycle company recycle system from the perspective of value chain and analyzes the approach to improve the efficiency of recycling system. It creates a model against current traditional recycling mechanism which contains production, consumption and recycling process with a queuing theory as a base. Related cost and benefit calculation are analyzed based on an example simulation, an empirical application in two sharing bicycle companies are discussed as well. Result shows that, if the ration of operating cost of each recycle station and the average reduction cost each bicycle recycle can meet a range between the average number of bicycles in recycle station and the average number of bicycles waiting to be recycled, the sharing bicycle resource recycle efficiency can be improved, accordingly, it can not only alleviate the urban environmental problems as it allows idle assets to gain more usage but also generate more frequent economic activity, the bicycle companies have a value adding in sharing bicycle operation from the efficiency improvement. The comparison between two major sharing bicycle enterprises (OFO and Mobike) with two different schemes in China indicates that the model with self-source of damaged bicycles recycling are more beneficial than the model with the public help of the damaged bicycles recycling.

Efficiency Improvement of Wireless Charging System Based on Active Power Source in Receiver

Wireless charging technology adapts to the electrified, lightweight, and intelligent trends of electric vehicle development. However, energy efficiency of wireless charging is still lower than conductive charging, and it is important for the wireless charging system to achieve global efficiency optimization in a constant current–constant voltage (CC–CV) charging operation. This paper proposes a novel system configuration, which adds an active power source into the receiver of the wireless charging system. It is proved that the efficiency can be increased significantly with amplitude and phase of the active power source be properly set. A novel current decoupling algorithm is used to analyze the efficiency of the new configuration, and a simulation model is established to validate the theoretical result and to explain the mechanism of efficiency improvement. The simulation shows that the active power source is able to change the power distribution and the current balance, and as a result, the efficiency increases in part of the operating region. The proposed configuration is realized in the experiment and then the efficiency improvement is demonstrated. The experimental result shows that the efficiency increases from 84.9% to 95.7% in a low coupling and slightly detuning working condition.

Design and Analysis of a Novel Split Sliding Variable Nozzle for Turbocharger Turbine

Variable geometry turbine (VGT) has been widely applied in internal combustion engines to improve engine transient response and torque at light load. One of the most popular VGTs is the variable nozzle turbine (VNT) in which the nozzle vanes can be rotated along the pivoting axis and thus the flow passage through the nozzle can be adjusted to match with different engine operating conditions. One disadvantage of the VNT is the turbine efficiency degradation due to the leakage flow in the nozzle endwall clearance, especially at small nozzle open condition. With the purpose to reduce the nozzle leakage flow and to improve turbine stage efficiency, a novel split sliding variable nozzle turbine (SSVNT) has been proposed. In the SSVNT design, the nozzle is divided into two parts: one part is fixed and the other part can move along the partition surface. When sliding the moving vane to large radius position, the nozzle flow passage opens up and the turbine has high flow capacity. When sliding the moving vane to small radius position, the nozzle flow passage closes down and the turbine has low flow capacity. As the fixed vane does not need endwall clearance, the leakage flow through the nozzle can be reduced. Based on calibrated numerical simulation, there is up to 12% turbine stage efficiency improvement with the SSVNT design at small nozzle open condition while maintaining the same performance at large nozzle open condition. The mechanism of efficiency improvement in the SSVNT design has been discussed.

The role of Sb in solar cell material Cu2ZnSnS4

In this study, based on first-principles calculations we report a possible mechanism of efficiency improvement of Sb-doped Cu2ZnSnS4 (CZTS) solar cells from the Sb-related defect point of view.

Privatization and efficiency: a mixed oligopoly approach

While models of mixed oligopoly have been analyzed within a rapidly growing literature, little is known about the mechanism of efficiency improvement relating to partial privatization. In this paper, we endogenize efficiency improvement in relation to the level of privatization. We show that in the short run, an improvement in efficiency associated with a state-owned firm reduces the output substitution among firms, and that the reduction in output substitution effect is proportional to the strength of the improvement in efficiency. Specifically, if the effect of efficiency improvement is sufficiently small, the magnitude of the improvement of social welfare is reduced. In the literature, the optimal policy in the long run is full nationalization. However, we argue that the optimal policy for a state-owned firm is partial privatization. Moreover, efficiency improvement provides the impetus for indirect entry regulation of private entrants.

Application of different surrogate models on the optimization of centrifugal pump

An optimization process for impellers was carried out based on numerical simulation, Latin hypercube sampling (LHS), surrogate model and Genetic algorithm (GA) to improve the efficiency of residual heat removal pump. The commercial software ANSYS CFX 14.5 was utilized to solve the Reynolds-averaged Navier-Stokes equations by using the Shear stress transport turbulence model. The impeller blade parameters, which contain the blade inlet incidence angle Δβ, blade wrap angle φ, and blade outlet angle β 2, were designed by random sample points according to the LHS method. The efficiency predicted under the design flow rate was selected as the objective function. The best combination of parameters was obtained by calculating the surrogate model with the GA. Meanwhile, the prediction accuracies of three surrogate models, namely, Response surface model (RSM), Kriging model, and Radial basis neural network (RBNN), were compared. Results showed that the calculated findings agree with the experimental performance results of the original pump. The RSF model predicted the highest efficiency, while the RBNN had the highest prediction accuracy. Compared with the simulated efficiency of the original pump, the optimization increased efficiency by 8.34% under the design point. Finally, the internal flow fields were analyzed to understand the mechanism of efficiency improvement. The optimization process, including the comparison of the surrogate models, can provide reference for the optimization design of other pumps.

Effect of Blend Composition and Additives on the Morphology of PCPDTBT:PC71BM Thin Films for Organic Photovoltaics.

The use of solvent additives in the fabrication of bulk heterojunction polymer:fullerene solar cells allows to boost efficiencies in several low bandgap polymeric systems. It is known that solvent additives tune the nanometer scale morphology of the bulk heterojunction. The full mechanism of efficiency improvement is, however, not completely understood. In this work, we investigate the influences of blend composition and the addition of 3 vol % 1,8-octanedithiol (ODT) as solvent additive on polymer crystallization and both, vertical and lateral morphologies of poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta [2,1-b;3,4-b']dithiophene)-alt-4,7(2,1,3-benzothiadiazole)] and [6,6]-phenyl C71-butyric acid methyl ester (PCPDTBT:PC71BM) blend thin films processed from chlorobenzene-based solutions. The nanoscale morphology is probed with grazing incidence small- and wide-angle X-ray scattering as well as X-ray reflectivity and complemented with UV/vis spectroscopy. In PCPDTBT:PC71BM films the use of ODT is found to lower the solubility of fullerene in the polymer matrix and to promote polymer crystallization, both vertical and lateral microphase separation with morphological coarsening, and formation of a fullerene-rich topping layer. The enhanced photovoltaic performance is explained by these findings.

Interfacial modification of photoelectrode in ZnO-based dye-sensitized solar cells and its efficiency improvement mechanism

A ZnO compact layer prepared by a sol–gel method was introduced into a photoelectrode at the interface between fluorine-doped tin oxide (FTO) substrate and a mesoporous ZnO layer in ZnO-based dye-sensitized solar cells (DSSCs). The ZnO compact layer was characterized by field-emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) and UV-Vis spectroscopy. The compact layer increased the photoelectric conversion efficiency of ZnO-based DSSCs by 20%. An electrochemical impedance spectroscopy (EIS) study demonstrated that the compact layer strikingly reduced the interfacial resistance in the device by enhancing the conductive contact between nanocrystalline ZnO and FTO substrate. The photocurrent density–voltage characteristics in the dark suggests that the compact ZnO layer also plays the role of a blocking layer suppressing the charge recombination, which is illustrated by the suppression of dark current density. The two effects effectively elevate the short circuit current density (JSC) and open circuit voltage (VOC), and finally improve the overall conversion efficiency of ZnO-based DSSCs.

Demand Curvature in Mixed Oligopoly: An Implication of Privatization

While models of mixed oligopoly have been analyzed within a rapidly growing literature, little is known about the mechanism of efficiency improvement relating to partial privatization. In this paper, we endogenize efficiency improvement in relation to the level of privatization. We show that in the short run, an improvement in efficiency associated with a state-owned firm reduces the output substitution among firms, and that the reduction in output substitution effect is proportional to the strength of the improvement in efficiency. Specifically, if the effect of efficiency improvement is sufficiently small, the magnitude of the improvement of social welfare is reduced. In the literature, the optimal policy in the long run is full nationalization. However, we argue that the optimal policy for a state-owned firm is partial privatization. Moreover, efficiency improvement provides the impetus for indirect entry regulation of private entrants.

The Relative Efficiency of Departments at a Turkish Engineering College: A Data Envelopment Analysis

In this study, Data Envelopment Analysis is used to measure relative efficiencies of academic departments of an engineering college. Input and output criteria are determined and measured utilizing the academic personnel performance measurement scheme of the College. New measures are developed to compare departments of different disciplines. The discriminating power of the measurement models is improved by restricting criteria weights directly and by using a multiple criteria decision making approach. Sensitivity of the results to exclusion of a criterion and changes in relative importance of the criteria is analyzed. Evaluation of the results jointly by the college administration and the departments is explained for a successful efficiency improvement mechanism.