Modulation Strategy Research Articles

IF-EDAAN: An information fusion-enhanced domain adaptation attention network for unsupervised transfer fault diagnosis

Unlike domain adaptation methods that rely on single-source information for transfer diagnosis, multi-source information-based domain adaptation methods can leverage the extensive diagnostic features derived from multiple sources of data. However, the issues of potential feature conflicts, the critical fault information loss, and high computational burdens still hinder effective applications of multi-source information domain adaptation for transfer diagnosis. For resolving these issues, this study proposes an unsupervised multi-source information domain adaptation approach for transfer fault diagnosis, which utilizes an information fusion-enhanced domain adaptation attention network (IF-EDAAN). Firstly, an information fusion method that converts multi-source information into a fused image using principal component analysis and signal-to-image conversion is employed to enhance and compress data from both the source and target domains. Then, a parameter-free attention mechanism (PFAM) module is proposed to adaptively focus on the domain-invariant temporal and spatial features of information fusion samples. Subsequently, the weight assignment module and joint maximum mean discrepancy metric strategy are proposed to mitigate negative transfer, thus enabling the effective extraction and alignment of domain-invariant temporal and spatial features. Finally, experiment validations on two rotating machinery datasets have been comprehensively elaborated to verify the efficacy and advantages of our proposed IF-EDAAN approach for transfer fault diagnosis across different working conditions. Experiment results have proved that our proposed IF-EDAAN approach can rapidly adapt to new transfer diagnostic scenarios with impressive performance and outperform several mainstream unsupervised domain adaptation approaches.

Dirhodium-Catalyzed Asymmetric Transformations of Alkynes via Carbene Intermediates.

ConspectusFunctionalization of alkynes is an established cornerstone of organic synthesis. While numerous transition metals exhibit promising activities in the transformations of alkynes via π-insertion or oxidative cyclometalation, Lewis π-acids offer a different approach. By coordinating with alkynes through π-bonding, Lewis π-acids facilitate nucleophilic addition, leading to the formation of alkenyl metal species. These species can undergo electron rearrangement to generate metal carbenes, which are crucial intermediates for subsequent carbene transfer reactions. This reaction pathway provides a versatile route for alkyne functionalization, especially in an asymmetric manner. Although the Lewis π-acid, gold(I), pioneered this reaction mode, the development of asymmetric variants remains challenging due to the linear coordination of gold(I). Therefore, expanding the range of catalysts beyond gold(I) complexes to other metal catalysts would facilitate further advances in chiral molecule construction and the exploration of novel reaction modes.In this Account, we present a concise review of alkyne multifunctionalization via dirhodium-catalyzed asymmetric transformations, providing the development of the modulation strategies and substrates and plausible reaction mechanisms. In the aromatization-driven strategy, the furanyl dirhodium carbene is generated from an enynone, which is terminated by enantioselective intramolecular C-H insertion, cyclopropanation, aromatic substitution, or the Büchner reaction, giving chiral dihydroindoles, dihydrobenzofurans, cyclopropane-fused tetrahydroquinolines, fluorenes, or cyclohepta[b]benzofurans. The cap-tether modulation strategy was developed in a subsequent study to balance the reactivity and selectivity of an azo-enyne. This strategy gave the first catalytic asymmetric cycloisomerization of azo-enyne, affording centrally and axially chiral isoindazole derivatives. The synergistic activation strategy, i.e., EWG activation and C-H···O interaction, was introduced to achieve the first dirhodium-catalyzed asymmetric cycloisomerization of enynes, providing a range of chiral cyclopropane-annulated bicyclic systems from enynals. Benefiting from these successes, difluoromethyl-substituted enynes were designed and proven to be effective substrates. With the corresponding benzo-1,6-enynes as the substrates, the enantioselective biscyclopropanation and the cascaded cyclopropanation/cyclopropenation were achieved using alkynes as dicarbene equivalents. Additionally, benzo-1,5-enynal generated vinyl dirhodium carbene, which reacted with a variety of alkenes via [2 + 1] cycloaddition, [4 + 3] cycloaddition, or formal allylation, giving spiro and fused polycyclic heterocycles. Coupling the synergistic activation strategy with desymmetrization, we further successfully achieved the asymmetric cycloisomerization of diynals, constructing furan-fused dihydropiperidines with an alkyne-substituted aza-quaternary stereocenter. Notably, by analyzing X-ray structures of several dirhodium-alkyne π-complexes, together with the results of DFT calculations and control experiments, we obtained evidence supporting the synergistic activation mode, making the well-defined paddlewheel-like dirhodium(II) stand out among the other metal complexes. We anticipate that our research will significantly advance the fields of dirhodium, alkyne, and carbene chemistry.

Modulation strategy of dynamic voltage restorer based on dual-feedforward active disturbance rejection compound controller

Modulation strategy of dynamic voltage restorer based on dual-feedforward active disturbance rejection compound controller

Advances in understanding the effects of cardiopulmonary bypass on gut microbiota during cardiac surgery.

Cardiopulmonary bypass (CPB) is an indispensable technique in cardiac surgery; however, its impact on gut microbiota and metabolites remains insufficiently studied. CPB may disrupt the intestinal mucosal barrier, altering the composition and function of gut microbiota, thereby triggering local immune responses and systemic inflammation, which may lead to postoperative complications. This narrative review examines relevant literature from PubMed, Web of Science, Google Scholar, and CNKI databases over the past decade. Keywords such as "gut microbiota," "cardiopulmonary bypass," "cardiac surgery," and "postoperative complications" were employed, with Boolean operators used to refine the search results. The review examines changes in gut microbiota before and after CPB, their role in postoperative complications, and potential strategies for modulation to improve outcomes.

Structure-Based Virtual Screening Identifies 2-Arylthiazole-4-Carboxylic Acids as a Novel Class of Nanomolar Affinity Ligands for the CaMKIIα Hub Domain.

The Ca2+/calmodulin-dependent protein kinase II α (CaMKIIα) plays a crucial role in regulating neuronal signaling and higher brain functions, being involved in various brain diseases. Utilization of small molecules targeting the CaMKIIα hub domain has proved to be a promising strategy for specific CaMKIIα modulation and future therapy. Through an in silico structure-based virtual screening campaign, we herein identified 2-arylthiazole-4-carboxylic acids as a new class of high-affinity CaMKIIα hub ligands. Particularly, the 2,6-dichlorophenyl analog, PTCA (compound 1a), displayed mid-nanomolar affinity (pKi = 7.2) and substantial stabilization of the CaMKIIα hub oligomer upon binding. Moreover, the tert-butyl ester prodrug, 14a, was developed to facilitate the brain delivery of PTCA and demonstrated remarkable enhancement in brain penetration compared to PTCA per se after systemic administration. Altogether, our study highlights that PTCA represents a novel and powerful tool compound for future pharmacological interventions targeting CaMKII kinase in the brain.

Design and Implementation of 3 kW All-SiC Current Source Inverter

In this paper, the optimal design and implementation of a silicon-carbide (SiC) power semiconductor-based current source inverter (CSI) with a power rating of 3 kW focusing on high power density are discussed in detail. The proposed methodology integrates analytical and numerical techniques to optimize the design of passive components, including filter capacitors and the DC-link inductor, and provides a comprehensive analysis of power semiconductor losses. The losses in the DC-link inductor as well as in the output capacitor are strongly dependent on the modulation strategy. Semi-analytical loss models are therefore derived for the most advanced modulation strategy, which are subsequently used to increase volumetric power density. The theoretical findings are experimentally validated using an ultra-compact, high-efficiency 3 kW three-phase CSI prototype operating at up to 100 kHz switching frequency. The experimental results confirm the efficiency of the proposed design and demonstrate its potential for high-power, compact drive applications.

Enhanced Sodium Storage and Thermal Safety of NaNi1/3Fe1/3Mn1/3O2 Cathode via Incorporation of TiN and WO3.

This study proposes an efficient, cost-effective, and industrially scalable electrode modulation strategy, which involves directly adding a small amount of high thermal and high conductance TiN and well interface compatible WO3 to NaNi1/3Fe1/3Mn1/3O2 (NaNFMO-TW) cathode slurry, to effectively reduce electrode polarization and interface side reactions, reduce the Ohmic heat and polarization heat of the battery, and ultimately to significantly improve the sodium-ion storage and thermal safety performance of the battery. At room temperature (RT) and 1C rate, the modified NaNFMO-TW electrode exhibits a reversible capacity of ∼95 mAh g-1 after 300 cycles, with a capacity retention rate of 82.6%, being higher than the 50.7% for NaNFMO. Furthermore, the assembled pouch battery with NaNFMO-TW retains 58.2% capacity after 300 cycles at RT&0.5C, being conspicuously superior to the 46.1% achieved by the NaNFMO||HC battery. In particular, adiabatic thermal tests and infrared thermal imaging tests reveal a marked improvement in the thermal safety of the modified battery, with a reduction in surface temperature of ∼1.3 and ∼2.2 °C during 3C charging and discharging, respectively. Moreover, the results confirmed the performance enhancement mechanism of NaNFMO by addition of TiN and WO3. Such electrode modulation strategy provides a practical method for improving battery performance.

Controlling the energies of the single-rotor large wind turbine system using a new controller

In wind energy generation systems, ensuring high energy quality is critical but is often compromised due to the limited performance and durability of conventional regulators. To address this, this work presents a novel controller for managing the machine-side inverter of a single-rotor large wind turbine system using an induction machine-type generator. The proposed controller is designed using proportional, integral, and derivative error-based mechanisms, which fundamentally differ from traditional proportional-integral (PI) regulators. Key features of the proposed regulator include its simplicity, cost-effectiveness, ease of implementation, reduced number of gains, and rapid dynamic response.This regulator enhances the direct power control (DPC) approach, as it integrates two tailored controllers alongside a pulse width modulation strategy to manage the machine inverter. The DPC strategy incorporating the proposed controller was implemented and tested using MATLAB, with various simulations to evaluate its performance and effectiveness. The proposed regulator demonstrated a significant improvement over the PI regulator, with reductions in active power ripples of 69%, 61.70%, and 59.14% across different tests. Additionally, the steady-state error of reactive power was reduced by 54.84%, 85.23%, and 62.68%, and the total harmonic distortion of current decreased by 48.12%, 50.55%, and 56.05%. These results underscore the high efficiency, robustness, and effectiveness of the proposed controller in improving system performance compared to conventional PI regulators. The controller’s outstanding performance makes it a promising solution for broader industrial applications.

P0896 A double-blind, randomized, placebo-controlled, single-center, pilot study evaluating the efficacy of a synbiotic formulation in modulating gut microbiota biodiversity in patients with mild-to-moderate UC in clinical and endoscopic remission

Abstract Background Intestinal dysbiosis is considered a key factor in the pathogenesis and disease progression of Ulcerative Colitis (UC). Probiotics, prebiotics, and synbiotics are promising strategies for microbiota modulation and could play a role as "add-on" therapies to available drugs. Our primary aim was to characterize the ability of a synbiotic containing Boswellia, Quercetina, Bromelina, Vit. D3, Lactobacillus rhamnosus GG, Inulin, FOS, and Tryptophan in modulating fecal microbiota composition, maintaining disease remission, and controlling the quality of life in patients with Ulcerative Colitis in clinical and endoscopic remission. Methods In our double-blind single-center proof-of-concept study, 26 UC patients in clinical and endoscopic remission were enrolled and randomly divided into 2 treatment arms. One group was treated with 5-ASA + placebo and the other with the synbiotic + 5-ASA for a period of 6 months. At baseline and after 6 months disease activity was assessed through the clinical and endoscopic Mayo Score, while quality of life was evaluated through the Psychological General Well-Being Index (PGWBI) and the Gastrointestinal Symptom Rating Scale (GSRS) scores. 16S rRNA gene sequencing was used to analyze gut microbiota composition at both time points. Results At microbial analyses, the Mann-Whitney test applied on the Shannon-Weiner, Simpson, and Chao1 indices did not reveal any statistically significant difference after 6 months compared with baseline. Also, the PERMANOVA test applied on the distance matrix calculated with the Bray Curtis and Unweighted Unifrac algorithms did not show statistically significant dissimilarities between the two time points. At disease evaluation at baseline, overall only 4 patients (15%) had a Full Mayo Score (FMS) of 1, while all the others had FMS = 0. After 6 months of follow-up, 3 patients experienced a flare with an FMS ≥ 2, and 4 patients (21%) had a worsening of the Mayo endoscopic subscore from 0 to 1. In this scenario, no significant differences were registered between the two groups of patients. At quality of life evaluation, patients treated with the synbiotic experienced a significant improvement in both the psychological/general well-being and gastrointestinal symptoms scores compared with baseline and placebo-treated group. No adverse events were registered. Conclusion Our proof-of-concept study shows that the treatment with this synbiotic formulation used in addition to 5-ASA can improve both psychological and gastrointestinal symptoms in patients with UC while maintaining their clinical and endoscopic remission. No direct effects have been observed on gut microbiota modulation. Further investigations are underway to confirm these findings.

Critical Review of Wireless Charging Technologies for Electric Vehicles

As the world transitions towards sustainable transportation, the advancement of electric vehicles (EVs) has become imperative. Wireless power transfer (WPT) technology presents a promising solution to enhance the convenience and efficiency of EV charging while alleviating the challenges associated with traditional wired systems. This paper conducts an in-depth exploration of WPT technologies for EVs, focusing on their theoretical foundations, practical implementation, optimization strategies, development trends, and limitations. The theoretical principles of wireless charging are first elucidated, categorizing them into near-field methods, such as inductive and capacitive charging, and far-field methods, including microwave and laser-based charging. A comparative analysis reveals the advantages and limitations inherent to each technology. The implementation section examines various charging strategies, encompassing stationary, dynamic, and quasi-dynamic wireless charging, assessing their feasibility and effectiveness in practical applications. Furthermore, optimization techniques aimed at enhancing WPT system performance are examined in depth, with particular emphasis on coil structure optimizations, anti-misalignment solutions, compensation topology optimizations, modulation strategy optimizations, and parameter identifications. The discussion section outlines current development trends in wireless charging technologies for EVs, highlighting the limitations that hinder the widespread adoption of wireless charging technologies in the EV market. Finally, potential research directions and the implications of wireless charging technology on the development of EVs are summarized. This critical review aims to provide valuable insights for researchers and practitioners dedicated to advancing the field of wireless charging for EVs.

A local shrinkage approach for creating dynamic hot-spots on thermoresponsive nanocellulose-based SERS substrate.

Surface-enhanced Raman scattering (SERS) is a highly sensitive technology to detect target analytes. The construction of dynamic "hot-spots" represents a significant approach to enhancing detection sensitivity. Herein, a hybrid plasma platform with dynamic "hot-spots" was developed for SERS recognition based on the assembly of gold nanospheres (AuNSs) on temperature-sensitive bacterial cellulose (BC) film grafted with poly(N-isopropylacrylamide) (PNIPAM). The dynamic "hot-spots" structure was regulated in-situ by local conformational contraction of the grafted thermoresponsive PNIPAM around the BC backbone without changing the overall morphology of the substrate. Moreover, the heating process was simplified by utilizing the plasma photothermal effect of AuNSs to regulate the "hot-spot" structure. The dynamic regulation measured value of the Raman signal of Rhodamine 6G (R6G) was increased by 6.5-times, and the SERS substrate exhibited extremely high sensitivity with a limit of detection (LOD) of 8.47×10-9 g/L and a relative standard deviation (RSD) of 9.24%. Meanwhile, it can accurately detect the pesticide residues of thiram on apple peel with the detection limit of 6.54×10-11 g/L. This dynamic "hot-spot" modulation strategy via local structural regulation has significant potential to improve the convenience, flexibility, and sensitivity of on-site SERS detection.

Electrochemical Ammonia Synthesis at p-Block Active Sites Using Various Nitrogen Sources: Theoretical Insights.

Electrochemical nitrogen conversion for ammonia (NH3) synthesis, driven by renewable electricity, offers a sustainable alternative to the traditional Haber-Bosch process. However, this conversion process remains limited by a low Faradaic efficiency (FE) and NH3 yield. Although transition metals have been widely studied as catalysts for NH3 synthesis through effective electron donation/back-donation mechanisms, there are challenges in electrochemical environments, including competitive hydrogen evolution reaction (HER) and catalyst stability issues. In contrast, p-block elements show unique advantages in light of higher selectivity for nitrogen activation and chemical stability. The present article explores the potential of p-block element-based catalysts as active sites for NH3 synthesis, discussing their activation mechanisms, performance modulation strategies, and future research directions from a theoretical perspective.

Nonalloyed α-phase formamidinium lead triiodide solar cells through iodine intercalation.

Formamidinium lead triiodide (FAPbI3) is considered the most promising composition for high-performing single-junction solar cells. However, nonalloyed α-FAPbI3 is metastable with respect to the photoinactive δ-phase. We have developed a kinetic modulation strategy to fabricate high-quality and stable nonalloyed α-FAPbI3 films, assisted by cogenetic volatile iodine intercalation and decalation. The intercalation of iodine facilitated the formation of corner-sharing Pb-I framework building blocks and reduced the kinetic barrier for α-FAPbI3 formation, whereas the iodine decalation improved the final perovskite film quality in terms of composition purity and overall homogeneity. Solar cells based on this nonalloyed α-FAPbI3 (free of other extrinsic composition ions) achieved a power conversion efficiency of >24%. The devices also exhibited excellent durability, retaining 99% of their original power conversion efficiency after operating for more than 1100 hours at 85° ± 5°C under illumination.

Modulating Interface of Ni-Embedded Hollow Porous Ti3C2Tx MXene Film Toward Efficient EMI Shielding.

Since the explosive growth of state-of-the-art electronics and devices raises concerns about electromagnetic pollution, exploring novel and efficient electromagnetic interference (EMI) shielding materials is desirable and crucial. Ti3C2Tx MXenes hold significant EMI shielding potential due to their inherent characteristics, including lightweight, metal-like conductivities, unique layered structure, and facile processing. Nonetheless, it remains challenging to fabricate Ti3C2Tx MXenes-based EMI shielding materials with efficient shielding capability and low reflection. Herein, an interface modulating strategy is designed to fabricate Ni-embedded hollow porous Ti3C2Tx MXene film. Benefiting from this strategy, the impedance matching is enhanced and the magnetic loss is simultaneously introduced. The multiple reflections, Ohmic loss, magnetic loss, and interfacial polarization concurrently contribute to the EMI shielding mechanism of the film. Accordingly, the film delivers an impressive EMI shielding effectiveness (SET) of 70.7dB at a thickness of ≈55µm, whilst the average reflection effectiveness (SER) is only 17.4dB. The specific EMI shielding effectiveness (SSE/t) is as high as 35126 dB∙cm2∙g-1. This study demonstrates a novel and effective routine for constructing EMI shielding materials with superior shielding capability and minimal reflection.

Impedance matching assistance based on frequency modulation for capacitively coupled plasmas

The efficiency and repeatability of capacitively coupled plasma (CCP) processes are highly dependent on achieving precise impedance matching between the plasma load and the RF power supply. This paper presents a numerical investigation of the role of frequency modulation in enhancing impedance matching of RF CCPs, a technique that can be critical to maintaining operational efficiency and plasma stability. Through a detailed simulation approach, the research explores how variations in the driving frequency impact plasma characteristics and electrical parameters, particularly focusing on the CCP’s impedance behavior. The simulations demonstrate that when impedance matching is achieved at a fixed fundamental frequency of 13.56 MHz, changes in driving frequency will lead to reduced power coupling efficiency and increased reflection. The study introduces a frequency modulation strategy that allows us to re-establish high-quality impedance matching after changes of the plasma impedance occur, e.g., due to changes of the variable capacitor settings inside the matchbox or gas pressure, thereby improving the CCP’s performance. As the driving frequency can be adjusted electrically, adjusting the impedance matching by frequency modulation is much faster than based on mechanical adjustments of variable capacitors inside the matching and could, thus, allows quicker matching. The findings underscore the impact of frequency modulation on power absorption efficiency and highlight the sensitivity of impedance matching to driving frequency fluctuations. This study provides a foundation for further exploration into the optimization of RF CCP systems with the potential to enhance process control and plasma performance across a range of industrial applications, especially pulsed CCPs.

A Modulation Strategy for Suppressing Current Ripple in H7 Current Source Inverters Through Coordinated Switching Operations

The DC bus current ripple is a critical performance parameter affecting the operation of current source inverters (CSIs). In high-power applications, CSIs often operate at lower switching frequencies to minimize losses. However, maintaining low levels of DC bus current ripple necessitates the use of large inductors on the DC side, which increases the size, weight, and cost of the system. This paper first explores the inherent limitations of conventional CSI designs. Subsequently, it proposes a hierarchical coordinated switching modulation strategy based on the H7 current source inverter (H7-CSI) to address the issue of DC bus current ripple. By segmenting the zero-vector states, the proposed method fully utilizes the modulation freedom of the H7-CSI, achieving high-frequency chopping effects on the DC-side current. Experimental results show that the new modulation strategy reduces the amplitude of DC bus current ripple to 43% of that achieved by conventional CSIs under similar switching loss conditions. Furthermore, the dynamic performance of the proposed scheme remains consistent with conventional CSIs. Spectrally, this method exhibits improved performance in the low-frequency range and slightly degraded performance in the high-frequency range, although the latter remains within acceptable limits.

Precision microbial regulation: Strategies for modulating GIT microbiota for host health

AbstractRecent advancements in analytical techniques have unveiled the spatiotemporal diversity of the gastrointestinal tract (GIT) microbiota and their associations with host well‐being. Despite these insights, the precise regulation of GIT microbiota remains a significant challenge. Currently, microbial regulatory strategies, including fecal microbiota transplantation (FMT), synthetic microbial communities (SynComs), genetically engineered microorganisms (GEMs), phages, and nanomaterials, are increasingly utilized for their precise influence on GIT microbiota. This review emphasizes the necessity for developing targeted regulatory strategies in GIT and provides a comprehensive summary and comparison of these approaches to explore their regulatory potential. We discuss recent advancements in these strategies, focusing on their mechanisms, efficacy, safety considerations, clinical trials, and optimization at the application level. Finally, we highlight support methods for optimizing modulation strategies, including the timing of microbial regulation, the selection of microbial targets, and the importance of monitoring the gastrointestinal environment to guide effective microbial interventions.

The Overview for the Stability Improvement Strategy of LIBS Spectrum and Analysis Model: From Physics System to Analysis Method.

Laser-induced breakdown spectroscopy (LIBS) technology has been widely used in many fields including industrial production, space exploration, medical analysis, environmental pollution detection, etc. However, the stability problem of LIBS is one of the core problems for its further development. Solutions in the LIBS field in recent decades were summarized and classified from the physical mechanism and analysis method. In particular, the processing methods based on the features of the plasma image and reconstructed image were analyzed and expounded. At the physical mechanism level, the system improvement strategy, environmental modulation strategy, and sample pretreatment improvement strategy were summarized and classified as a pre-improvement strategy. At the analysis method level, two kinds of correction strategies were concluded according to the difference between the feature mediums of the plasma spectrum and image, which were classified as a later improvement strategy. Strategies and methods were discussed in detail, which can provide a basic architecture and reference for the research of LIBS stability improvement. Moreover, the potential developing trend for this topic was proposed.

Improved modulation strategy for asymmetric eleven-level cascaded H-bridges

Improved modulation strategy for asymmetric eleven-level cascaded H-bridges

Exploring Potential Complement Modulation Strategies for Ischemia-Reperfusion Injury in Kidney Transplantation.

The complement system plays a crucial role in regulating the inflammatory responses in kidney transplantation, potentially contributing to early decline in kidney function. Ischemia-reperfusion injury (IRI) is among the factors affecting graft outcomes and a primary contributor to delayed graft function. Complement activation, particularly the alternative pathway, participates in the pathogenesis of IRI, involving all kidney compartments. In particular, tubular epithelial cells often acquire a dysfunctional phenotype that can exacerbate complement activation and kidney damage. Currently, complement-modulating drugs are under investigation for the treatment of kidney diseases. Many of these drugs have shown potential therapeutic benefits, but no effective clinical treatments for renal IRI have been identified yet. In this review, we will explore drugs that target complement factors, complement receptors, and regulatory proteins, aiming to highlight their potential value in improving the management of renal IRI.