High Efficiency Output Research Articles

What is holding back business process virtualization in the post-COVID-19 era? Based on process virtualization theory (PVT).

The post-pandemic COVID-19 has been influential in accelerating the digital transformation of enterprises and business process virtualization. However, in a virtual working environment with no physical interaction, the psychological requirements of the communication between teleworkers and the negative impact of information systems are hindering the business process virtualization. Studying the relationship between the interaction between organizational members and job performance is an important part of organizational psychology. For an enterprise to maintain high-efficiency output, it is necessary to study psychological factors related to business process virtualization. This paper verified the factors hindering business process virtualization based on process virtualization theory (PVT). The research was implemented on a sample of 343 teleworkers in China enterprises. The structure of the model of this study includes two aspects that hinder the business process virtualization: the psychological requirements of teleworkers (Sensory requirements, Synchronism requirements, and Relationship requirements) and the negative effects of information systems (Information overload and Communication overload). The results show that teleworkers' sensory requirements, synchronism requirements, and communication overload negatively impact business process virtualization. However, unlike the results in the existing literature, the relationship requirements and information overload do not affect the business process virtualization. The results will help business managers, teleworkers, and information system developers develop strategies to address the negative factors hindering business process virtualization. In the so-called new "normal era," our research will help companies to create a successful virtual work environment.

High-performance Kerr microresonator optical parametric oscillator on a silicon chip

Optical parametric oscillation (OPO) is distinguished by its wavelength access, that is, the ability to flexibly generate coherent light at wavelengths that are dramatically different from the pump laser, and in principle bounded solely by energy conservation between the input pump field and the output signal/idler fields. As society adopts advanced tools in quantum information science, metrology, and sensing, microchip OPO may provide an important path for accessing relevant wavelengths. However, a practical source of coherent light should additionally have high conversion efficiency and high output power. Here, we demonstrate a silicon photonics OPO device with unprecedented performance. Our OPO device, based on the third-order (χ(3)) nonlinearity in a silicon nitride microresonator, produces output signal and idler fields widely separated from each other in frequency ( > 150 THz), and exhibits a pump-to-idler conversion efficiency up to 29 % with a corresponding output idler power of > 18 mW on-chip. This performance is achieved by suppressing competitive processes and by strongly overcoupling the output light. This methodology can be readily applied to existing silicon photonics platforms with heterogeneously-integrated pump lasers, enabling flexible coherent light generation across a broad range of wavelengths with high output power and efficiency.

Fullerene Lattice‐Confined Ru Nanoparticles and Single Atoms Synergistically Boost Electrocatalytic Hydrogen Evolution Reaction

AbstractThe design and construction of electrocatalysts with high efficiency, low cost and large current output suitable for industrial hydrogen production is the current development trend for water electrolysis. Herein, a lattice‐confined in situ reduction effect of the 3D crystalline fullerene network (CFN) is developed to trap Ru nanoparticle (NP) and single atom (SA) via a solvothermal‐pyrolysis process. The optimized product (RuNP‐RuSA@CFN‐800) exhibits outstanding electrocatalytic performance for alkaline hydrogen evolution reactions. To deliver a current density of 10 mA cm−2, the RuNP‐RuSA@CFN‐800 merely required an overpotential of 33 mV, along with a robust electrocatalytic durability for 1400 h. Even at large current densities of 500 and 1000 mA cm−2, the overpotentials are only 154 and 251 mV, respectively. Density function theorey calculation results indicated that the electronic synergetic effect between Ru NP and SA enable to regulate the charge distribution of RuNP‐RuSA@CFN‐800 and reduce the Gibbs free energy of intermediate species for water dissociation process, thereby accelerating the hydrogen evolution process. Moreover, the robust CFN matrix render this strategy patulous to other transition metals, e.g., Cu, Ni, and Co. The present study provides a new clue for the construction of novel electrocatalyst in the field of energy storage and conversion.

Developing a microwave-driven reactor for ammonia synthesis: insights into the unique challenges of microwave catalysis

Reactor requirements grow with scale as new phenomena can become more and more relevant, creating trends that we've observed in the development of microwave-driven ammonia synthesis – a technique with a unique combination of high output and energy efficiency.

Dynamic modeling and disturbance rejection compensation for hysteresis nonlinearity of high voltage piezoelectric stack actuators

High voltage piezoelectric stack actuators (HVPSA) are widely used in the field of active vibration control of engineering structures due to their strong load capacity, fast response rate, and high mechanical output efficiency. However, their inherent hysteresis will have a direct impact on the stability and control efficiency of the piezoelectric active control system. To compensate the hysteresis nonlinearity of HVPSA, a high-precision dynamic hybrid method based on linear active disturbance rejection control (LADRC) is proposed. Starting from the hysteresis analysis of piezoelectric actuators, an exponential function butterfly-shape hysteresis operator is constructed and combined with the asymmetric Bouc–Wen model to present a novel hybrid static hysteresis model. In order to implement rate-dependent hysteresis modeling, the Hammerstein rate-dependent hysteresis model of HVPSA is further established, and its inverse model is built for feedforward compensation. Subsequently, the LADRC is used to adjust the driving voltage in real time to form the hysteresis closed-loop compensator of HVPSA. The experimental results show that the Hammerstein rate-dependent hysteresis model established has satisfactory modeling accuracy in the working voltage range and frequency band under consideration. Furthermore, compared with the traditional inverse model feedforward compensation strategy, the proposed hybrid compensation method based on LADRC improves the compensation efficiency by more than 11% and reduces the hysteresis nonlinearity of HVPSA to less than 3%, with strong anti-disturbance ability.

Facile design of flexible Pd nanoclusters sensitized reduced graphene oxide paper film towards hydrogen sensing

Developing flexible gas sensors based on reduced graphene oxide (rGO) are highly promising for practical application, however, it is still challenging due to the sacrificed solution-processibility and mechanical properties after reduction. To address this issue, we here introduce solution-processed rGO and designed a flexible hydrogen (H2) film sensor by coupling with Pd nanoclusters as the activators via direct colloids mixing and subsequent vacuum filtration. The rGO/Pd nanocluster film features with structural compactness, surface homogeneity, excellent mechanical flexibility, high-efficiency output, and simplification of compositing method. In addition, the film sensor exhibited high response value, fast behavior and stable sensing behavior towards high-concentration H2 compared with bare rGO film owing to the significant activation role of Pd nanoclusters with ultrasmall sizes (average size: 3.3 nm). Conclusively, this work provides an ingenious and effective way for the design of rGO-based flexible sensor, and shows promise for efficient portable and cost-effective monitoring of environmentally H2 gases leaks.

Emergy evaluation of biogas production system in China from perspective of collection radius

Biogas production has become one of the main renewable energy utilization modes in Chinese rural areas. In this study, emergy theory was employed to assess the ecological sustainability of biogas production system based on the case of Weilai energy company. Emergy radius formulas derived from biogas production characteristics were constructed to illustrate the relationship between the degree of system development and biomass supply distance. The calculated emergy results showed that the biogas production system required an average of 1.98 E+14sej emergy inputs in the process of utilizing one-ton agricultural waste. And the emergy indicators implied that the system had a low degree of social resource input and environmental loading, indicating that the system could keep high output efficiency and ecological sustainability. The biomass recycling distance (9.93 km) which was calculated from emergy radius demonstrated better ecological performance and higher waste utilization degree than that of economic recycling distance (7.57 km). Biomass recycling distance based on emergy theory would provide a comprehensive understanding for the biogas production development.

Usefulness of a new DUV-LED device for the control of infection by Escherichia coli, Staphylococcus aureus, mycobacteria and spore-forming bacteria

Reliable disinfection and sterilization technologies are needed to deal with the various infectious diseases spreading around the world. Furthermore, bacteria that are difficult to eliminate by ordinary disinfection are also a problem in the medical environment. We examined the germicidal effect of a newly developed deep-ultraviolet light-emitting diode (DUV-LED) prototype device (wavelength of 280 ± 5 nm; power of 0.9 to 1.4 mW/cm2) for floor sterilization against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), Mycobacterium gordonae (M. gordonae), and Bacillus subtilis (B. subtilis). This prototype device is equipped with highly practical DUV-LEDs with a high output efficiency and a long life, and was designed with consideration of the irradiation distance and the angle of the DUV-LEDs to provide a uniform irradiation rate. We found a statistically significant reduction of ≥90% in the infectious titers of both E. coli and S. aureus after irradiation for 2 s. Although acid-fast bacilli and spore-type bacilli are generally thought to be resistant to UV light irradiation compared to general bacteria, the acid-fast bacillus M. gordonae was inactivated after irradiation for 10 s, and spore-type cells of the bacillus B. subtilis were inactivated by ≥90% after irradiation for 30 s. We also found that the effects were cumulative when irradiation was performed at intervals. In the future, the usefulness of this device as an infection control measure will be evaluated in daily medical practice.

Design and Experimental Research of a Compact Ku-Band Triaxial Klystron Amplifier With Low Seed Injection Power

A compact Ku-band triaxial klystron amplifier (TKA) with three cascaded single-gap bunching cavities is proposed for the sake of high output efficiency at low seed injection power. The three bunching cavities are specially designed with optimal external quality factors and specific drift tube length to suppress the self-oscillation of these cavities. By decreasing the coupling coefficients and increasing the frequency interval of the three cavities, the asymmetric mode competition can be successfully eliminated in 3D particle-in-cell simulation. The compact TKA is demonstrated to be capable of producing the Ku-band high power radiation with a peak power of 580 MW corresponding to an efficiency of 31 % and a pulse duration of nearly 100 ns in typical experiments. Furthermore, the seed injection power and axial length of the proposed device are reduced to 9 kW and 10 wavelengths, respectively.

Investigation and Application of Magnetic Properties of Ultra-Thin Grain-Oriented Silicon Steel Sheets under Multi-Physical Field Coupling

Nowadays, energy shortages and environmental pollution have received a lot of attention, which makes the electrification of transportation systems an inevitable trend. As the core part of an electrical driving system, the electrical machine faces the extreme challenge of keeping high power density and high efficiency output under complex workin g conditions. The development and research of new soft magnetic materials has an important impact to solve the current bottleneck problems of electrical machines. In this paper, the variation trend of magnetic properties of ultra-thin grain-oriented silicon steel electrical steel (GOES) under thermal-mechanical-electric-magnetic fields is studied, and the possibility of its application in motors is explored. The magnetic properties of grain-oriented silicon steel samples under different conditions were measured by the Epstein frame method and self-built multi-physical field device. It is verified that the magnetic properties of grain-oriented silicon steel selected within 30° magnetization deviation angle are better than non-grain-oriented silicon steel. The magnetic properties of the same ultra-thin grain-oriented silicon steel as ordinary non-oriented silicon steel deteriorate with the increase in frequency. Different from conventional non-grain-oriented silicon steel, its magnetic properties will deteriorate with the increase in temperature. Under the stress of 30 Mpa, the magnetic properties of the grain-oriented silicon steel are the best; under the coupling of multiple physical fields, the change trend of magnetic properties of grain-oriented silicon steel is similar to that of single physical field, but the specific quantitative values are different. Furthermore, the application of grain-oriented silicon steel in interior permanent magnet synchronous motor (IPM) for electric vehicles is explored. Through a precise oriented silicon steel motor model, it is proved that the magnetic flux density of stator teeth increases by 2.2%, the electromagnetic torque of motor increases by 2.18%, and the peak efficiency increases by 1% after using grain-oriented silicon steel. In this paper, through the investigation of the characteristics of grain-oriented silicon steel, it is preliminarily verified that grain-oriented silicon steel has a great application prospect in the drive motor (IPM) of electric vehicles, and it is an effective means to break the bottleneck of current motor design.

Size effect of piezoelectric energy harvester for road with high efficiency electrical properties

In order to further improve the power generation properties of the piezoelectric energy harvester inside the piezoelectric device for road, this paper presents a stacked piezoelectric energy harvester with high electrical output and energy output efficiency for road energy harvesting, which improves the power generation properties of the existing road piezoelectric power technology. Based on the electrical theory, the size parameters related to the electrical properties are clarified. And based on the size effect, the electrical law is analyzed. Subsequently, the output voltage and power of energy harvesters with different sizes are studied under the different traffic conditions. At the same time, considering the processing and testing errors, an energy generation calculation method of energy harvester is deduced, and the energy output efficiency is clarified. The results indicate that the diameter has the greatest influence on the electrical properties, the Φ15-h30 mm energy harvester has the best performance under the random traffic conditions of vehicles with different loads and different speeds. Under the condition of SUV car, the maximum voltage and power are 86 V and 39.2 mW, the generated energy and output electric energy are 69.2 mJ and 14.7 mJ within 2 s, the energy output efficiency reaches 21.4 %. The improvement of the electrical properties of the energy harvester inside the piezoelectric device will be beneficial to the application process of converting road waste vibration energy into clean energy. And the energy generation calculation method will provide a reference for the piezoelectric energy and other energy technologies.

A Low Impedance Current-Reuse Path for UWB-PA to Improve Efficiency and Gain

Current-reuse circuit with a low impedance current-reuse path has been proposed to enrich high flat gain, high efficiency, and high output power across the operating band. While an inductor-capacitor (LC) interstage is employed to improve the linearity of the proposed PA. In the second stage, the shunt peaking design in a common-source circuit is employed to improve the power gain, while a network of reactance compensation is adopted at the output of the second stage to overcome the parasitic capacitance's impact on the active device. The post-layout simulation using the TSMC 65 nm CMOS process is carried out on the entire frequency range from 3.1 GHz to 10.6 GHz. The post-layout simulation achieved ±42 ps group delay variation, 32% power-added efficiency (PAE), and 32-dB power gain. Matching input and output of less than −10 dB has been achieved over the operating band, and it achieved an output power of 18.3 dBm.

Highly efficient long-lasting triboelectric nanogenerator upon impact and its application to daily-life self-cleaning solar panel

Triboelectric nanogenerators (TENGs) have the potential to harvest energy from any type of movement; however, most TENGs are designed for low-frequency movement due to their low energy conversion efficiency with high-frequency movements such as impacts. In this paper, a TENG with high energy conversion efficiency and long-lasting output from impacts is proposed. This design is for a freely oscillating, non-contact TENG that employs a freely oscillating structure without frictional contact and which exhibits persistent output after impacts. It provides the capacity to light 20 LEDs for 10 s upon a single instantaneous impact. Owing to its freely oscillating structure, the energy conversion efficiency is up to 50.8%, which is significantly higher than that of other TENGs that use impacts. This platform was then applied to develop a self-cleaning solar panel system, which effectively removed 79.2% of the dust from the test panel surface after twelve impacts. Collectively, this work provides a strategy for harvesting energy from impacts and offers a useful application for self-cleaning solar panels.

Elimination of self-oscillation between three cascaded reflectors in an X-band triaxial klystron amplifier

Self-oscillation of three cascaded reflectors easily occurs in a triaxial klystron amplifier (TKA) since the TEM mode leakage cannot be cut off by a coaxial waveguide. To solve this issue, we propose a non-uniform reflector to obtain an optimal external quality factor, which indicates its minimum TEM mode leakage. The self-oscillation of three non-uniform reflectors is then suppressed by selecting a specific drift tube length between them. Moreover, different eigenfrequencies are chosen for the three improved reflectors to enhance the tolerance of the drift tube length between them. With these methods, the self-oscillation of three cascaded reflectors can be successfully eliminated, and a TKA with high output efficiency is capable of achieving a long pulse output.

A compact coaxial relativistic klystron amplifier with three cascaded single-gap bunching cavities for efficient output

A compact coaxial relativistic klystron amplifier (RKA) with three cascaded bunching cavities is investigated to obtain high efficiency output in this paper. When the injection power and drift tube length are both decreased for the compactness of the initial coaxial RKA, the conversion efficiency of this device decreases to only 20%, which is mainly due to the insufficient modulation of intense relativistic electron beam (IREB). To solve this issue, three cascaded bunching cavities are designed to strengthen the modulation of IREB, and each bunching cavity is designed to a non-uniform single-gap cavity with a high external quality factor. Moreover, a specific drift tube length is chosen for minimizing the TEM mode leakage between every two adjacent cavities. With these methods, the self-oscillation between input and three cascaded bunching cavities can be successfully suppressed without loading any reflectors. The proposed three cascaded single-gap bunching cavities are further examined in a Ku-band coaxial RKA, and the output efficiency of this device increases to 44%, which is more than twice that of the initial coaxial RKA. Furthermore, the injection power and axial length of the propagating IREB in the improved coaxial RKA are reduced to only 5 kW and 10 wavelengths, respectively.

Promoting Reversible Dissolution/Deposition of MnO2 for High-Energy-Density Zinc Batteries via Enhancing Cut-Off Voltage.

Zn//MnO2 batteries based on the MnO2 /Mn2+ conversion reaction mechanism featuring high energy density, safety, and affordable cost are promising in large-scale energy storage application. Nonetheless, the continuous H+ intercalation at low potential reduces the average output voltage and the energy efficiency, impeding the development of the high-performance zinc battery. In this work, a strategy was proposed of enhancing the cut-off voltage from the perspective of electrochemical parameters, toward high energy efficiency and stable output voltage of the Zn//MnO2 battery. This strategy was beneficial to promoting MnO2 dissolution/deposition through the increase of acidity caused by the constant accumulation of MnO2 and inhibiting H+ (de)intercalation during cycling process, thereby improving the energy efficiency (83.5 %) along with the stable average output voltage (1.88 V) under the cut-off voltage of 1.8 V. This work provides a new pathway to promote aqueous zinc batteries with high energy density and stable output voltage.

Experimental Study on Transverse Mode Instability Characteristics of Few-Mode Fiber Laser Amplifier Under Different Bending Conditions

We studied the transverse mode instability (TMI) characteristics of few-mode fiber laser amplifier employing ytterbium-doped fiber (YDF) with core/cladding diameter of 30/400 μm under different bending diameters. The gain fiber is coiled in ellipse shape with minimum bending diameter changed from 9 cm, 10 cm, 11 cm to 12 cm in the bending part, and the experimental results show an anomaly characteristic of TMI. The TMI threshold improved from 772 W, 1149 W and 1458 W to 1641 W when the bending diameter of YDF increase from 9 cm, 10 cm, 11 cm to 12 cm, accompanied by the deterioration of beam quality from 1.60, 1.67, 1.87 to 1.95. This is mainly because tightly bending in few-mode fiber will promote the overlap between modes and lead to mode coupling, which may trigger TMI. Besides, the bending losses of HOMs decrease while bending diameter increasing, so that there is higher output efficiency and deteriorated beam quality when bending diameter increase. Although the phenomenon is not agreed with common TMI with near single-mode fiber laser, the result will be helpful for the design and power scaling of few-mode fiber lasers.

Biodiesel production from transesterification of Australian Brassica napus L. oil: optimisation and reaction kinetic model development

Edible oil-based feedstocks based biodiesel is still leading the industry around the world. Canola oil (Brassica napus L.) contributes significantly to that race. Process optimisation and the development of reaction kinetic models of edible oil feedstocks are still required since the knowledge of kinetics is needed for designing industrial facilities and evaluating the performance of catalysts during transesterification or other related processes in a biorefinery. This research focuses on the transesterification process for biodiesel production because of its higher output efficiency, reactivity with feedstock, techno-economic feasibility in terms of FFA content, and environmental sustainability. The response surface method with the Box–Behnken model was used to optimise the process. Multivariate analysis of variance (ANOVA) was also performed to investigate the effectiveness of the regression model. The optimal process conditions were found to be 5.89 M methanol, 0.5% (w/w) KOH, 60 °C and 120 min. The predicted yield was 99.5% for a 95% confidence interval (99.1, 99.9). The experimental yield was 99.6% for these conditions. Two different kinetic models were also developed in this study. The activation energy was 16.9% higher for the pseudo-first-order irreversible reaction than for the pseudo-homogenous irreversible reaction. Such a comprehensive analysis will assist stakeholders in evaluating the technology for industrial development in biodiesel fuel commercialisation.

An economical and specific purification process of human haptoglobin 1-1

Human haptoglobin (Hp) 1–1 is a potential protein drug to eliminate toxic effects of free hemoglobin, however it was difficult to selectively purify Hp 1–1 from pooled plasma. In this work, a specific purification process of Hp 1–1 from pooled human plasma was introduced, with PEG precipitation as the key step. First, frozen human plasma was thawed on ice to remove condensed proteins, then Hp 1–1, Hp 2–1 and Hp 2–2 were all precipitated by ammonium sulfate between 40%–65% (0 °C) saturation. 50% (m/v) PEG4000 solution (dissolved in 0.2 M HAc-NaAc pH 5.0) was then added into the pellet resuspension, and Hp 2–1, Hp 2–2 were precipitated between the concentration of 6%–15% (m/v) while Hp 1–1 remained in the 15% supernatant. The purity of Hp 1–1 raised from < 5% to a maximum of 50% after this step. Finally, Hp 1–1 with a maximum purity of > 98% was prepared after refined purification including anion exchange chromatography and hydrophobic chromatography. This process has a total Hp 1–1 recovery of 76.97%, along with characteristics of low cost, high efficiency, and high output, making it a process applicable for large-scale purification of Hp 1–1 from human plasma.

High‐Efficiency E‐Beam Pumped Deep‐Ultraviolet Surface Emitter Based on AlGaN Ultra‐Thin Staggered Quantum Wells

AbstractA 2‐inch wafer‐scale electron‐beam (e‐beam) pumped deep‐ultraviolet surface emitter (DUVSE) with high efficiency and high output power at an emission wavelength of 248 nm is reported. This DUVSE benefits from ultra‐thin staggered AlN/AlGaN/GaN multiple quantum wells (MQWs), which compromise the electron–hole overlap and carrier confinement and thus significantly improve the emission efficiency. The wall‐plug‐efficiency (WPE) is increased by six times to 5.25% in comparison to that of conventional DUV light‐emitting devices (LEDs) based on AlGaN MQWs. This WPE is achieved under an anode voltage and current of 8 kV and 1 mA, where the output power is 420 mW. This output power can be further enhanced to 702 mW by increasing the anode current to 3 mA. The enhanced WPE and uniform electron beam distribution lighten the avenue to achieve a wafer‐scale high power dense DUV light source, which is a challenge for conventional DUV‐LEDs, in particular with an emission wavelength of less than 250 nm.