High Power Research Articles

Determinants and impacts of supply chain responsiveness: an empirical research

PurposeThe aim of this study is to identify the factors affecting supply chain responsiveness. Additionally, it investigates the relationships between supply chain responsiveness, customer satisfaction and competitive power.Design/methodology/approachA quantitative method was adopted. Data were collected from 290 companies operating in Turkey and tested with structural equation modeling.FindingsThe results show that supply chain responsiveness is related to continuous process improvement, supplier integration and environmental uncertainty but not to customer integration. The findings also present relationships between supply chain responsiveness, customer satisfaction and competitive power.Practical implicationsThe findings indicate that decision-makers should invest in continuous process improvement and supplier integration. They also need to understand that their supply chain responsiveness depends on the environmental dynamism of their sectors, and they must direct their efforts accordingly. Finally, decision-makers wishing high customer satisfaction and competitive power must value supply chain responsiveness and take necessary actions to achieve it.Originality/valueA literature review for this study indicated very limited empirical evidence of the relationship between continuous process improvement, supplier integration, customer integration, environmental uncertainty and supply chain responsiveness. Similarly, there was a quest for more research on the relationships between supply chain responsiveness, customer satisfaction and competitive power. This work will enhance the literature by adding knowledge in these areas.

Dynamic of mode transition in air surface micro-discharge plasma: reactive species in confined space

Flexible surface micro-discharge plasma is a non-thermal plasma technique used for treating wounds in a painless way, with significant efficacy for chronic or hard-to-heal wounds. In this study, a confined space was designed to simulate wound conditions, with gelatin used to simulate wound tissue. The distinction between open and confined spaces was explored, and the effects of temperature, humidity, discharge power and the gap size within the confined space on the plasma characteristics were analyzed. It was found that temperature, humidity and discharge power are important factors that affect the concentration distribution of active components and the mode transition between ozone and nitrogen oxides. Compared to open space, the concentration of ozone in confined space was relatively lower, which facilitated the formation of nitrogen oxides. In open space, the discharge was dominated by ozone initially. As the temperature, humidity and discharge power increased, nitrogen oxides in the gas-phase products were gradually detected. In confined space, nitrogen oxides can be detected at an early stage and at much higher concentrations than ozone concentration. Furthermore, as the gap of the confined space decreased, the concentration of ozone was observed to decrease while that of nitrate increased, and the rate of this concentration change was further accelerated at higher temperature and higher power. It was shown that ozone concentration decreased from 0.11 to 0.03 μmol and the nitrate concentration increased from 20.5 to 24.5 μmol when the spacing in the confined space was reduced from 5 to 1 mm, the temperature of the external discharge was controlled at 40 °C, and the discharge power was 12 W. In summary, this study reveals the formation and transformation mechanisms of active substances in air surface micro-discharge plasma within confined space, providing foundational data for its medical applications.

Stakeholder analysis of banning unhealthy product advertisement in Iran

BackgroundThe advertising of unhealthy products, including unhealthy foods, drugs with abuse potential, certain cosmetic products and services, and tobacco, has raised significant public health concerns due to its role in increasing consumption and contributing to the rise of non-communicable diseases. Policy development and enforcement in this area necessitate an in-depth analysis of the relevant stakeholders. This study aims to examine the stakeholders involved in regulating the advertisement of unhealthy products in Iran, providing critical evidence for shaping advertising regulations and reducing the societal consumption of such products.MethodsThis qualitative study, conducted in 2022, involved 18 experts experienced in the area of unhealthy product advertisement in Iran. Participants were selected through purposive and snowball sampling methods. The stakeholders' roles, power, positions, and interests were analyzed using Schmeer's guidelines.Results17 stakeholders were identified as relevant to the ban on unhealthy product advertisements, of whom 14 were classified as active and three as inactive. Key stakeholders included radio and television broadcasters, the Ministries of Health, Culture, and Industry, as well as political institutions. The Ministry of Health (MOHME) emerged as a leading advocate for the ban, while the Ministries of Culture and Industry, along with political institutions, were identified as possessing significant power with moderate support for the policy. In contrast, broadcasters and social media platforms were powerful opponents of the ban.ConclusionsThe study underscores the pivotal role of stakeholders with high power and medium interest in the success of policies aimed at banning unhealthy product advertisements. Key challenges included conflicts of interest, insufficient penalties for organizations violating advertising regulations, organizational disputes, limited human and financial resources, lack of clear implementation guidelines, weak community engagement, and inadequate oversight. Engaging key stakeholders effectively could mitigate these obstacles and facilitate more effective health policy interventions in the future.

Dual-Discriminator Conditional Generative Adversarial Network-based LDPC-Coded OFDM Free-Space OCS for Improving BER Analysis

This paper proposes a Dual-Discriminator Conditional Generative Adversarial Network-based LDPC-Coded OFDM Free-Space OCS for Improving BER Analysis (LDPC-OFDM-FSO-DDcGAN). The proposed LDPC-OFDM-FSO-DDcGAN method containsthe transmitter model, the channel model and the receiver model. The binary data are given to the encoder of LDPC in the transmitter model and the input data encode previously controlling the situation using QAM. To decrease the effects of fading caused by turbulence, the channel model intends a probability density function with FSO-DDcGAN. The maximal ratio combing (MRC), equal gain combining (EGC) and selection combining (SC) can be employed by the combiner to integrate the signal once it has been received from the FSO channel. The combiner is used to improve one signal by combining the several signals received. The bit of data is transformed towards a sequential stream after combiner. The proposed Probability Density Function (PDF) offers high SNR gain, BER reduction and power efficiency when combined with DDcGAN. To achieve large coding gain, the standard coding methods of LDPC are used through only a code percentage as realistic to imitation data. The proposed LDPC-OFDM-FSO-DDcGAN technique is executed in MATLAB. The LDPC-OFDM-FSO-DDcGAN method provides higher power efficiency and lower bit error rate analysed with the existing models.

Joint Fault Diagnosis of IGBT and Current Sensor in LLC Resonant Converter Module Based on Reduced Order Interval Sliding Mode Observer

LLC resonant converters have emerged as essential components in DC charging station modules, thanks to their outstanding performance attributes such as high power density, efficiency, and compact size. The stability of these converters is crucial for vehicle endurance and passenger experience, making reliability a top priority. However, malfunctions in the switching transistor or current sensor can hinder the converter’s ability to maintain a resonant state and stable output voltage, leading to a notable reduction in system efficiency and output capability. This article proposes a fault diagnosis strategy for LLC resonant converters utilizing a reduced-order interval sliding mode observer. Initially, an augmented generalized system for the LLC resonant converter is developed to convert current sensor faults into generalized state vectors. Next, the application of matrix transformations plays a critical role in decoupling open-circuit faults from the inverter system’s state and current sensor faults. To achieve accurate estimation of phase currents and detection of current sensor faults, a reduced-order interval sliding mode observer has been designed. Building upon the estimation results generated by this observer, a diagnostic algorithm featuring adaptive thresholds has been introduced. This innovative algorithm effectively differentiates between current sensor faults and open switch faults, enhancing fault detection accuracy. Furthermore, it is capable of localizing faulty power switches and estimating various types of current sensor faults, thereby providing valuable insights for maintenance and repair. The robustness and effectiveness of the proposed fault diagnosis algorithm have been validated through experimental results and comparisons with existing methods, confirming its practical applicability in real-world inverter systems.

Power Distance Moderates the Relation Between Income Inequality and Life Satisfaction: A Cross-Country Longitudinal Analysis.

Despite extensive research, the relationship between income inequality and life satisfaction remains unclear, with some countries experiencing negative consequences, while others show neutral or positive outcomes. Using data from the Gallup World Poll (2006-2022) with nearly two million respondents from more than 110 countries, we disentangle the distinct within-country and between-country effects of inequality. Our multilevel analyses reveal a significant within-country effect: Temporal increases in inequality are associated with decreases in life satisfaction. At the between-country level, power distance-a cultural dimension reflecting tolerance for social disparities-moderates the relationship. In low power distance countries, higher inequality strongly predicts lower life satisfaction, whereas in high power distance countries, the effect is nonsignificant. These findings are robust across two measures of income inequality and controls for wealth and individualism, offering a refined methodological and cultural interpretation to resolve inconsistencies in prior cross-national research.

Flexible solid-state supercapacitors based on biowaste-derived activated carbon and nanomaterials for enhanced performance.

Supercapacitors are energy storage devices with long cycle life that can harvest and deliver high power. This makes them attractive for a broad range of applications including flexible and lightweight wearable consumer electronics. In this work, we fabricate flexible solid-state supercapacitors with improved capacitance and cycle life. We synthesize activated carbon (AC) from cabbage leaves as a low cost, biowaste-derived active electrode material. To improve mechanical flexibility and conductivity, we incorporate reduced graphene oxide sheets (RGO) and carbon quantum dots (CQDs) into the electrodes. We show that at the optimum AC/RGO/CQD composition, the capacitance of the solid-state supercapacitor is maximized while its scan rate dependence and bending stability are simultaneously improved. We envision that this approach offers significant potential for delivering efficient energy storage devices for consumer electronics.

Raman scattering impairments caused by 50G-PON introduction and mitigation techniques

We explore the impact of stimulated Raman scattering (SRS) in the context of multiple PON generations sharing the same optical distribution network. The 50G-PON, being the last specified ITU-T PON, imposes the use of high launch power to meet strong optical path loss requirements. We show that the XGS-PON upstream could be the first victim of the introduction of 50G-PON since its wavelength spacing maximizes Raman scattering. We exploit a model to describe both in simulation and experiment the SRS-induced depletion on XGS-PON. Assuming that 50G-PON will be deployed on the current passive infrastructure, we also exploit field data to precisely predict the amount of terminations exceeding the requirements. The results show that up to 1.8 dB can be lost on XGS-PON upstream signals, 1.3 dB on the 50G-PON upstream, and 0.5 dB on the G-PON upstream, over a distance of 20 km of fiber. Up to 3% of terminations may be affected, according to our field data exploitation. Improving the receivers’ sensitivity through either better photodiodes, signal processing, or forward error correction could relax the high launch power constraints, and thus the SRS. Deploying an optical splitter at the central office could also limit the power actually launched into the fiber while meeting high split ratios. Finally, decreasing the 50G-PON downstream wavelength seems a possible option to mitigate the Raman scattering.

ZnSe⊂MoSe2/rGO Petal-like Assembly as Fast and Stable Sodium Ion Storage Anodes

The development of high energy and power density sodium-ion batteries (SIBs) has attracted increasing interest in the last two decades due to the abundance and cost-effectiveness of sodium resources. Herein, this study developed a self-templating synthetic method to construct MoSe2 nanosheets which were intercalated by ZnSe nanoparticles and were anchored on the in situ reduced graphene oxide layers. The thus-fabricated composites exhibited excellent Coulombic efficiency, a remarkable rate capability and an exceptionally long cycle life when being utilized as the anode in SIBs. Specifically, a reversible capacity of 265 mAh g−1 was achieved at 20 A g−1, which could be maintained for 6400 cycles. At an ultra-high rate of 30.0 A g−1, the anode retained a capacity of 235 mAh g−1 after 9500 cycles. Such a strong performance was attributed to its unique porous structure and synergistic interactions of multi-components. The underlying sodium storage mechanism was further investigated through various techniques such as in situ X-ray diffraction spectroscopy, the galvanostatic intermittent titration method, etc. Overall, this study illustrates the great potential of clad-structured multicomponent hybrids in developing high-performance SIBs.

GeTe/Sb2Te3 Super‐Lattices: Impact of Atomic Structure on the RESET Current of Phase‐Change Memory Devices

AbstractPhase change memories (PCMs) are at the heart of modern memory technology, offering multi‐level storage, fast read/write operations, and non‐volatility, bridging the gap between volatile DRAM and non‐volatile Flash. The reversible transition between amorphous and crystalline states of phase‐change materials such as GeTe or Ge2Sb2Te5 is at the basis of PCM devices. Despite their importance, PCM devices face challenges including high power consumption during the RESET operation. Current research efforts focus on improving device architecture and exploring alternative phase‐change materials such as GeTe/Sb2Te3 super‐lattices (SLs), for which a reduced programming power consumption is observed compared with standard PCMs. Herein, by combining X‐ray diffraction and scanning transmission electron microscopy imaging of SL thin films with the study of the same SL in PCM devices, it is shown that it is possible to significantly decrease RESET energy of the device, without modifying the SL composition, by reducing the amount of structural defects through annealing treatment. The best device properties are obtained after transforming the SL into a defect‐free, highly out‐of‐plane oriented rhombohedral phase. These results offer a promising avenue for further improving the performance of SL‐based PCM devices through structural optimization.

Minimizing Performance Loss in Blade‐Coated Large‐Area Perovskite Solar Cells Via Semi‐Sealed Gas Quenching

AbstractGas‐quenching of perovskite wet films is widely used in upscaling perovskite solar cells (PSCs). However, due to uneven and turbulent gas stream generated by traditional approaches through air knife or air gun, it is a challenge to induce homogeneous nucleation and produce high‐quality perovskite films suitable for large‐area PSCs. Here this work presents a semi‐sealed gas quenching (SSGQ) strategy that produces homogeneous low‐velocity large‐area high‐pressure gas flow to extract low‐boiling‐point solvents effectively, while leaving behind perovskite intermediates undisturbed that then turn into large crystalline grains. As a result, the SSGQ‐processed perovskite films exhibit improved crystallinity and reproducibility, suppressed defect density and residual stress, as well as compact buried interface and large‐scale uniformity. Such blade‐coated large‐area (1.0 cm2) PSCs with carbon and metal electrodes achieve high power conversion efficiencies (PCEs) of 19.5% and 23.3% (20.5% and 24.2% for 0.04 cm2), both with the lowest PCE loss of ≤1.0% among reported works. This work presents a scalable and affordable approach for fabricating high‐quality perovskite films and high‐performance perovskite photovoltaics, paving the way to PSC commercialization.

Sediment transport characteristics at the flood-event scale in the Minjiang River Basin, China

ABSTRACT In recent years, the significant change in the runoff–sediment distribution in the upper Yangtze River has led to an increased sediment contribution from the Minjiang River Basin (MRB) to the Three Gorges Reservoir. However, previous studies on sediment load changes in the MRB have focused mainly on annual-scale characteristics, thereby neglecting features driven by floods. Therefore, this study focused on examining the changes in flood-event sediment loads in the MRB based on mathematical statistics and comprehensive measurement data. The results indicated that human activities, climate change, and seismic events have caused an increasing trend in the flood-scale sediment load in the upper MRB and a decreasing trend in the lower MRB. The changes in the flood-scale sediment modulus at low runoff erosion power levels were greater than those at high runoff erosion power levels at different abrupt-change stages. During extreme flood events, the actual sediment concentration in the MRB remained below the sediment-carrying capacity. This study provides novel insights into water resource management during the flood season in the MRB and similar basins.

Investigation of deep trap states at the negative polarization interface of N-polar HEMT through capacitance-conductance measurements

Abstract N-polar high electron mobility transistors (HEMTs) will play a crucial role in the future high frequency and high power GaN based technology due to their inherent advantages over Ga-polar technology. However, still, there are some fundamental questions about N-polar technology that needs to be addressed. One of the questions that remained unanswered or regaining interest recently is the nature of the negative polarization interface of N-polar HEMTs. Two contradicting views exist regarding the nature of the negative polarization interface at the barrier/buffer interface of N-polar HEMT: one view suggests that hole-like trap states exist at this interface while the other view suggests that two-dimensional hole gas exists at this interface. To give a possible solution to this fundamental question, in this study, two N-polar HEMT heterostructures were investigated, one without any Si δ-doping at the barrier/buffer interface and the other with Si δ-doping at the sameinterface. Through capacitance-conductance measurements, existence of deep trap states at the negative polarization interface at barrier/buffer interface is demonstrated for the sample without Si δ doping- , which indirectly contradicts the idea of existence of hole gas at this interface. Moreover, in the capacitance-conductance measurements, Si δ-doping is shown to eliminate the presence of deep trap states.

Concurrently Boosting Activity and Stability of Oxygen Reduction Reaction Catalysts via Judiciously Crafting Fe–Mn Dual Atoms for Fuel Cells

The ability to unlock the interplay between the activity and stability of oxygen reduction reaction (ORR) represents an important endeavor toward creating robust ORR catalysts for efficient fuel cells. Herein, we report an effective strategy to concurrent enhance the activity and stability of ORR catalysts via constructing atomically dispersed Fe-Mn dual-metal sites on N-doped carbon (denoted (FeMn-DA)-N-C) for both anion-exchange membrane fuel cells (AEMFC) and proton exchange membrane fuel cells (PEMFC). The (FeMn-DA)-N-C catalysts possess ample dual-metal atoms consisting of adjacent Fe-N4 and Mn-N4 sites on the carbon surface, yielded via a facile doping-adsorption-pyrolysis route. The introduction of Mn carries several advantageous attributes: increasing the number of active sites, effectively anchoring Fe due to effective electron transfer to Mn (revealed by X-ray absorption spectroscopy and density-functional theory (DFT), thus preventing the aggregation of Fe), and effectively circumventing the occurrence of Fenton reaction, thus reducing the consumption of Fe. The (FeMn-DA)-N-C catalysts showcase half-wave potentials of 0.92 and 0.82V in 0.1M KOH and 0.1M HClO4, respectively, as well as outstanding stability. As manifested by DFT calculations, the introduction of Mn affects the electronic structure of Fe, down-shifts the d-band Fe active center, accelerates the desorption of OH groups, and creates higher limiting potentials. The AEMFC and PEMFC with (FeMn-DA)-N-C as the cathode catalyst display high power densities of 1060 and 746mWcm-2, respectively, underscoring their promising potential for practical applications. Our study highlights the robustness of designing Fe-containing dual-atom ORR catalysts to promote both activity and stability for energy conversion and storage materials and devices.

Research on Voltage Stability Strategy of Energy Storage Access to High Penetration Wind and Solar Power Distribution Network System with SOP (Soft Open Point)

Research on Voltage Stability Strategy of Energy Storage Access to High Penetration Wind and Solar Power Distribution Network System with SOP (Soft Open Point)

High Power Multi-Junction 808 nm Vertical Cavity Surface Emitting Lasers With High Efficiency

High Power Multi-Junction 808 nm Vertical Cavity Surface Emitting Lasers With High Efficiency

Directly Interconnected High-Energy and High-Power Battery Packs

Designing battery packs is a trade-off between power capability and capacity. Often, high power is only desired for short periods; otherwise, high capacities are preferred. To meet these requirements, hybrid packs comprising high-power and high-energy batteries can be used. However, a major drawback of these systems is the need for additional direct current to direct current converters, which increase the complexity, weight, and cost. By directly interconnecting high-power and high-energy battery strings in parallel, the current distribution is determined exclusively by Kirchhoff’s laws, which can lead to the overloading of individual batteries and thus to damage or dangerous failures. To overcome these problems, we developed a layout and control algorithm for directly interconnected packs that keeps them in a safe state by solely controlling the external power, which is governed by two additional requirements. These keep the discharge current of the high-energy element below the maximum charge current of the high-power element and the charge current of the high-energy element below the maximum discharge current of the high-power element while the pack is discharging or charging, respectively. As a proof of concept, a directly interconnected lithium-ion battery pack was successfully designed using the electrochemical simulation software Battery Simulation Studio 2021,which was tested and integrated into a Audi A3 cabriolet.

Pulse duration dependent effects of ultrafast laser induced damage on a 1030 nm multi-layer dielectric mirror for high repetition rate, high average power laser systems

Pulse duration dependent effects of ultrafast laser induced damage on a 1030 nm multi-layer dielectric mirror for high repetition rate, high average power laser systems

Absolute signal of stimulated Raman scattering microscopy: A quantum electrodynamics treatment.

The advent of stimulated Raman scattering (SRS) microscopy has launched a rapidly growing field in chemical imaging with broad impact. Although the physical picture seems to be well understood from classical models, prediction of absolute SRS signals remains a challenge. Here, we present a quantum electrodynamics treatment of the newly introduced stimulated Raman cross section. The resulting formula for calculating the absolute SRS signal is simple and differs from the commonly used relations by only one factor. We demonstrate the utility of this formula in a broad range of crucial applications of SRS microscopy, including stimulated Raman enhancement factor (>108 times), signal-to-noise ratio (SNR) of typical imaging experiments, population saturation under high power excitation, and energy deposition during stimulated Raman photothermal microscopy. In particular, the theory predicts that SRS microscopy is almost always more sensitive than spontaneous Raman microscopy for chemical imaging.

Enhanced proton acceleration using spiral-phase plasma mirrors

Abstract We present a method for generating intense vortex laser beams using spiral-phase plasma mirrors. These single-use micro-metric formations imprint a set amount of orbital angular momentum (OAM) to an arbitrary high power focusing beam. Using these beams, we irradiated ultrathin foils and measured the emission of ions from their back side. Utilizing a PW class laser, 5 J@45fs@2w resulting in an Intensity of 2×1020 W cm − 2 at spot focus, we observed an increase in the energy and numbers of these ions, compared to shots taken with reflection off flat plasma mirrors. A 45% increase in the proton numbers and a 35% increase in cutoff energy was observed. This is a major advance since the area of interaction and intensity are reduced due to the planar shape of the generated OAM laser. We review the available data-sets on laser ion acceleration using vortex beams, and conclude with a comparison to our findings.