Structural Conversion Research Articles

Closed-loop Implementation of a Non-isolated High Step-up Integrated SEPIC-CUK DC-DC Converter Structure with Single Switch

Closed-loop Implementation of a Non-isolated High Step-up Integrated SEPIC-CUK DC-DC Converter Structure with Single Switch

Stimuli-responsive Zn(ii) complexes showing the structural conversion and on/off switching of catalytic properties.

In this work, we report a series of dinuclear Zn(ii) complexes and their corresponding catalytic properties for a transesterification reaction. We show that the structures and catalytic activity of the complexes are strongly dependent on their molecular structures surrounding the metal centres. The use of halides yields a series of [Zn2X4L] (X = Cl, Br, and I) complexes with low catalytic activity because of the fully saturated coordination environment, whereas Zn(ClO4)2 results in two isomeric [ZnL] n 1D coordination polymers with efficient catalytic properties, despite being susceptible to structural rearrangement and consequent changes in catalytic activity over time. The response to chemical stimuli to trigger anion exchange allows for switching on/off the systems' catalytic activity, simultaneously recovering the catalytic effect upon degradation and thus reconstructing the coordination environment of the 1D polymer.

Tristate Converters with Limited Duty Cycle

Replacing the active switch of a DC/DC converter with a series connection of two active switches and a diode which is connected to the connection point of the two switches, changes the converter into a tristate one. The tristate concept changes the voltage transformation ratio of the original converter and influences the dynamics. Starting from a topology for limited duty cycles, four converters can be derived. There are two possibilities for the position of the second capacitor and so eight converter structures can be achieved. The position of the second capacitor influences the input current, the inrush, the stored energy, and the voltage stress of this component. When the input voltage has the other polarity, again eight converters can be designed. Changing all active electronic switches by current bidirectional ones (an electronic switch with an antiparallel diode) leads to bidirectional converters and increases the number of converters that are derived from the basic topology to thirty-two. The function of the four basic structures is explained, and the voltage transformation ratio calculated and graphically shown. The connections of the currents are explained. For one converter the large and the small signal models and two transfer functions are calculated, and simulation of the dynamics are shown.

Revolutionizing transportation composite structures: Lightweight, sustainable, and multi-scale hybrid design through waste tire-driven graphene, hemp fiber, and bio-based overmoulding

The pursuit of lightweight, environmentally friendly composite structures in transportation is crucial for minimizing ecological footprints and promoting energy-efficient manufacturing techniques. This study presents a novel approach by replacing traditional long glass fiber reinforced homopolymer polypropylene (homoPP) compounds with short hemp fiber reinforced homoPP, incorporating graphene nanoplatelets (GNP) derived from recovered carbon black via waste tire pyrolysis, resulting in a remarkable 15% weight reduction. With new compound formulation by adjusting the amounts of compatibilizer and GNP, injection moulding process was integrated with overmoulding process by using bio-based UD prepregs to enhance the adhesion of injected part and interfacial interaction by decreasing the stress concentrations in the structure. This novel hybrid composite design having 40 wt% hemp fiber, 1.0 wt% GNP and 2.7 wt% compatibilizer provided to improve flexural modulus and strength by 169% and 67.9%, respectively, compared to neat homoPP. The overmolding process employed bio-based natural fibers reinforced UD tapes as inserts, leading to an impressive enhancement of 211% in tensile modulus and 93.6% in strength, further surpassing the performance of neat homoPP. This work not only achieves the conversion of conventional composite structures into recyclable, sustainable thermoplastic composites but also introduces multi-scale reinforcements with customizable functionality, demonstrating a significant step forward in the development of environmentally conscious materials and manufacturing methods by adopting Life-Cycle Assessment (LCA) methodology regarding the sustainability of the newly developed composites.

Enantiomorph conversion in single crystals of the Weyl semimetal CoSi

Chiral intermetallic phases may show unusual chemical and physical properties with nontrivial structure-property relationship. It is therefore of particular interest to study the structural conversion between domains of different handedness. Here, the atomic decoration of the enantiomorph exchange area within single crystal of the Weyl semimetal CoSi is determined by a combination of atomic-resolution scanning transmission electron microscopy imaging, single crystal X-ray diffraction and quantum chemical analysis of atomic interactions. Two-atomic [CoSi] units are shown to be the bonding base for the FeSi-type structure and may be considered as ‘pseudo-molecules’, thinking of molecular organic crystals. Tiny reorganisation of atomic interactions within these units results in the appearance of sequence ‘faults’ in the structure pattern i.e. in a different structural motif in the enantiomorph exchange area, which – contrary to the A and B enantiomorphs of CoSi – contains an inversion centre and allows a local enantiomorph ‘conversion’. Due to the special features of atomic interactions, the reorganisation of multi-atomic bonds leads to slightly higher total energy. This appears within one and the same grain which is prepared by the short distance chemical vapor transport.

Cations induced in situ electrochemical amorphization for enhanced oxygen evolution reaction

Surface reconstruction is widely existed on the surface of transition metal-based catalysts under operando oxygen evolution reaction (OER) condition. The design and optimize the reconstruction process are essential to achieve high electrochemical active surface and thus facilitate the reaction kinetics, whereas still challenge. Herein, we exploit electrolyte engineering to regulate reconstruction on the surface of Fe2O3 catalysts under operando OER conditions. The intentional added cations in electrolyte can participate the reconstruction process and realize a desirable crystalline to amorphous structure conversion, contributing abundant well-defined active sites. Spectroscopic measurements and density functional theory calculation provide insight into the underlying role of amorphous structure for electron transfer, mass transport, and intermediate adsorption. With the assistant of Co2+ cations, the enhanced current density as large as 17.9 % can be achieved at 2.32 V (vs RHE). The present results indicate the potential of electrolyte engineering for regulating the reconstruction process and provide a generalized in-situ strategy for advanced catalysts design.

Two Ln-MOFs containing abundant Lewis acid sites as the efficient and heterogeneous catalyst to activate epoxides for cycloaddition of CO2

The burning of a large number of fossil fuels leads to the increase of CO2 content in the air, causing environmental problems such as greenhouse effect and ocean acidification, which has attracted wide attention. It is of great significance to utilize microporous metal-organic frameworks (MOFs) for carbon dioxide conversion and utilization. Herein, two MOFs {[Ln(dppa)(H2O)2·2H2O]·dima·H2O·0.5O} (1: Sm-MOF; 2: Gd-MOF; H4dppa = 5-(3′ 4′-dicar- boxylphenoxy) isophthalic acid, dima = dimethylamine, which is decomposed by DMF hydrothermal reaction), and its structural characterization and CO2 catalytic conversion performance were studied. The BET test of MOFs 1–2 shows that it has good microporosity. At 273 K and 298 K, MOFs 1–2 showed lower adsorption capacity for CH4, but higher adsorption capacity for CO2. The adsorption enthalpy of CO2 was calculated by Virial equation, and the adsorption selectivity of CO2 at different separation ratios was discussed respectively. The heterogeneity of MOFs 1–2 was proved by thermal filtration experiments. The reproducibility test shows that the catalyst structure is still intact after five cycles, indicating that the catalyst still has good repeatability. In addition, the catalytic mechanism of cycloaddition reaction was discussed.

SideNet: Learning representations from interactive side information for zero-shot Chinese character recognition

Existing methods for zero-shot Chinese character recognition usually exploit a single type of side information such as radicals, glyphs, or strokes to establish a mapping with the input characters for the recognition of unseen categories. However, these approaches have two limitations. Firstly, the mappings are inefficient owing to their complexity. Some existing methods design radical-level mappings using a non-differentiable dictionary-matching strategy, whereas others construct sophisticated embeddings to map seen and unseen characters into a unified latent space. Although the latter approach is straightforward, it lacks a learnable scheme for explicit structure construction. Secondly, the complementarity within multiple types of side information has not been effectively explored. For example, the radicals provide structural knowledge at an abstract level, whereas glyphs offer detailed information on their figurative counterparts. To this end, we propose a new method called SideNet that jointly learns character-level representations assisted by two types of interactive side information: radicals and glyphs. SideNet contains a structural conversion module that extracts radical knowledge via dimensional decomposition, and a spatial conversion module that encodes the radical counting map to produce an interactive outcome between radicals and glyph. Finally, we propose a new classifier that integrates the converted features by a similarity-guided fusion mechanism. To the best of our knowledge, this study represents the first attempt to integrate these two types of side information and explore a joint representation for zero-shot learning. Experiments show that SideNet consistently outperforms existing methods by a significant margin in diverse scenarios, including handwriting, printed art, natural scenes, and ancient Chinese characters, which demonstrates the potential of joint learning with multiple types of side information.

Subnanosecond microlaser pumped fan-out grating design MgO:PPLN optical parametric generator continuously tunable from near- to mid-infrared

An in-depth analysis and description of, to the best of our knowledge, the first subnanosecond pulse duration optical parametric generator (OPG) based on a fan-out grating design MgO-doped periodically-poled lithium niobate (MgO:PPLN) crystal is presented. Pumped by high energy subnanosecond pulse duration Q-switched Nd:YAG microlaser pulses, our OPG provides high output energies ranging from tens to hundreds of μJ with up to 45% conversion efficiency and enables fast and precise wavelength tuning across the near-to-mid infrared spectral regions (1414–4303 nm) just by laterally displacing the fan-out crystal without the need for temperature tuning. Limits of operation of the device were found in terms of the laser-induced damage threshold (LIDT) of the fan-out MgO:PPLN crystal. The OPG was fully characterized in terms of spectral, energy, and spatial properties of the signal wave, and analyzed experimentally and theoretically for the feasibility of producing broadband infrared output through non-collinear quasi-phase-matching and conversion of the fan-out grating structure into a chirped one.

An extract from the frass of swallowtail butterfly (Papilio machaon) larvae inhibits HCT116 colon cancer cell proliferation but not other cancer cell types

BackgroundThe frass of several herbivorous insect species has been utilised as natural medicines in Asia; however, the metabolite makeup and pharmaceutical activities of insect frass have yet to be investigated. Oligophagous Papilionidae insects utilise specific kinds of plants, and it has been suggested that the biochemicals from the plants may be metabolised by cytochrome P450 (CYP) in Papilionidae insects. In this study, we extracted the components of the frass of Papilio machaon larvae reared on Angelica keiskei, Oenanthe javanica or Foeniculum vulgare and examined the biological activity of each component. Then, we explored the expression of CYP genes in the midgut of P. machaon larvae and predicted the characteristics of their metabolic system.ResultsThe components that were extracted using hexane, chloroform or methanol were biochemically different between larval frass and the host plants on which the larvae had fed. Furthermore, a fraction obtained from the chloroform extract from frass of A. keiskei-fed larvae specifically inhibited the cell proliferation of the human colon cancer cell line HCT116, whereas fractions obtained from the chloroform extracts of O. javanica- or F. vulgare-fed larval frass did not affect HCT116 cell viability. The metabolites from the chloroform extract from frass of A. keiskei-fed larvae prevented cell proliferation and induced apoptosis in HCT116 cells. Next, we explored the metabolic enzyme candidates in A. keiskei-fed larvae by RNA-seq analysis. We found that the A. keiskei-fed larval midgut might have different characteristics from the O. javanica- or F. vulgare-fed larval metabolic systems, and we found that the CYP6B2 transcript was highly expressed in the A. keiskei-fed larval midgut.ConclusionsThese findings indicate that P. machaon metabolites might be useful as pharmaceutical agents against human colon cancer subtypes. Importantly, our findings show that it might be possible to use insect metabolic enzymes for the chemical structural conversion of plant-derived compounds with complex structures.

The Construction of Binary Phase Electrolyte Interface for Highly Stable Zinc Anodes.

Metal zinc is a promising anode candidate of aqueous zinc-ion batteries due to high theoretical capacity, low cost, and high safety. However, it often suffers from hydrogen evolution reaction (HER), dendrite growth, and formation of by-products. Herein, a triethyl phosphate (TEP)/H2 O binary phase electrolyte (BPE) interface is developed by introducing TEP-based electrolyte-wetted hydrophobic polypropylene (PP) separator onto the Zn anode surface. The equilibrium of the BPE interface depends on the comparable surface tensions of H2 O-based and TEP-based electrolytes on hydrophobic PP separator surfaces. The BPE interface induces Zn2+ solvation structure conversion from [Zn(H2 O)x ]2+ to [Zn(TEP)n (H2 O)y ]2+ , where most solvated H2 O molecules are removed. In [Zn(TEP)n (H2 O)y ]2+ , the residual H2 O molecules can be further constrained by the formation of H bonds between TEP and H2 O molecules. Consequently, the ionization of solvated H2 O molecules is effectively suppressed, and HER and by-products are effectively restricted on Zn anode surfaces in BPE. As a result, Zn anodes exhibit a high Coulombic efficiency of 99.12% and superior cycling performance of 6000h, which is much higher than the case in single-phase aqueous electrolytes. To illustrate the feasibility of BPE in full cells, the Zn/Alx V2 O5 batteries are assembled based on the BPE and exhibited enhanced cycling performance.

Thermodynamics of amyloid formation

AbstractBackgroundIs amyloid formation an exothermic process with the potential to damage brain tissue by local hyperthermia? In our study we aim to find answers to the above question. Several proteins, i.e. lysozyme and amyloid‐β peptide, known to form amyloid structures are investigated primarily by differential scanning calorimetry (DSC) in order to determine their thermodynamic properties.MethodExperiments in DSC are complemented by a set of other biophysical methods in order to clarify molecular parameters for the evaluation of the heat capacity measurements.ResultFor this purpose a seeded amyloid formation assay has been designed. In this assay the structural conversion of a given amount of monomeric protein is accelerated and synchronized by the addition of preformed amyloid fibril fragments to result in reproducible heat bursts caused by amyloid formation.ConclusionFirst results are reported and the measured enthalpies are related to known enthalpies from protein structural conversion processes.

Torrefaction of Flax Shives as a Process of Preparation Waste Vegetable Biomass for Energy Purposes

Abstract The use of processed biomass, derived from agricultural crop residues, as a fuel is becoming increasingly important in the energy sector, which additionally allows for the management of excess waste that is a burden on the environment. The aim of this study was to investigate the effect of the torrefaction process conditions in a carbon dioxide atmosphere on the chemical structure of biocarbon and the energy parameters of the produced product, which can be a solid biofuel. The biomass chosen for the experimental work was flax shive. Determinations of the heat of combustion of the produced biocarbon samples were carried out using a KL-10 calorimeter, and identification of the molecular structure of the product and the starting biomass was carried out using infrared spectrometry. It was confirmed that increasing the temperature of biomass torrefaction increases the heat of combustion of the product, with this parameter obtaining the most favourable value for biocarbon obtained during torrefaction at 320°C and for 20 to 30 minutes. The heat of combustion of the biocarbon produced during torrefaction at 320°C and for 30 minutes was 25.92 MJ/kg, with a feedstock mass loss of 41%. Such conditions lead to a significant conversion of the chemical structure of the biomass, with no complete destruction of organic structures.

Recasting the gold standard - part II of II: communicating healthcare options along a continuum of care.

This is the second part of a two-part series on spectrum of care that encourages practitioners to tailor case management to the patient along a continuum of acceptable options. Part I defined the spectrum of care and broadened its approach beyond initial cost-of-care considerations. This second article introduces strategies for initiating conversations with clients about their needs, wants and expectations specific to healthcare options and case management decisions. It will explore how open inquiry, reflective listening, transparency and unconditional positive regard facilitate dialogue between providers and their clients as they collaborate on decision-making along a spectrum of care. Contextual case management prioritizes interventions that are appropriate for both the patient and the client. To identify and explore which healthcare options represent the best fit for those impacted most by medical decisions, veterinarians need to make space for clients to feel comfortable sharing their perspectives. Clients are more likely to be engaged in decision-making when their insight is actively solicited. They have much to share with us as experts about their cat's overall health and wellness needs. Inviting clients to contribute to the consultation and being receptive to hearing what motivates their choices helps us to structure conversations around healthcare options. The ability to communicate healthcare options is as vital as the provision of healthcare, if not more so.

Continuous Synthesis of Spherical Polyelectrolyte Brushes by Photo-Emulsion Polymerization in a Microreactor.

Nanosized spherical polyelectrolyte brushes (SPBs) are ideal candidates for the preparation of nanometal catalysts, protein separation, and medical diagnostics. Until now, SPBs have been synthesized by photo-emulsion polymerization in a batch reactor, which remains challenging to scale up. This paper reports a successful continuous preparation of SPBs by photo-emulsion polymerization in a self-made microreactor. The effects of residence time, monomer concentration, and feed ratios on the conversion of monomers and SPB structures are systematically investigated by dynamic lighting scattering and transmission electron microscopy. Poly(acrylic acid) (PAA) SPBs obtained in a microreactor exhibiting a narrow size distribution with a short reaction time are very effective in inhibiting the calcium carbonate scale and are comparable to those produced in a batch reactor. This work confirms the feasibility of continuous preparation and scaled-up production of SPBs.

Cooking-Induced Oxidation and Structural Changes in Chicken Protein: Their Impact on In Vitro Gastrointestinal Digestion and Intestinal Flora Fermentation Characteristics.

Meat digestion and intestinal flora fermentation characteristics are closely related to human dietary health. The present study investigated the effect of different cooking treatments, including boiling, roasting, microwaving, stir-frying, and deep-frying, on the oxidation of chicken protein as well as its structural and digestion characteristics. The results revealed that deep-fried and roasted chicken exhibited a relatively higher degree of protein oxidation, while that of boiled chicken was the lowest (p < 0.05). Both stir-frying and deep-frying led to a greater conversion of the α-helix structure of chicken protein into a β-sheet structure and resulted in lower protein gastrointestinal digestibility (p < 0.05), whereas roasted chicken exhibited moderate digestibility. Further, the impact of residual undigested chicken protein on the intestinal flora fermentation was assessed. During the fermentation process, roasted chicken generated the highest number of new intestinal flora species (49 species), exhibiting the highest Chao 1 index (356.20) and a relatively low Simpson index (0.88). Its relative abundance of Fusobacterium was the highest (33.33%), while the total production of six short-chain fatty acids was the lowest (50.76 mM). Although stir-fried and deep-fried chicken exhibited lower digestibility, their adverse impact on intestinal flora was not greater than that of roasted chicken. Therefore, roasting is the least recommended method for the daily cooking of chicken. The present work provides practical advice for choosing cooking methods for chicken in daily life, which is useful for human dietary health.

Domain-Limited Sub-Nanometer Co Nanoclusters in Defective Nitrogen Doped Carbon Structures for Non-Invasive Drug Monitoring.

In this work, sub-nanometer Co clusters anchored on porous nitrogen-doped carbon (C─N─Co NCs) are successfully prepared by high-temperature annealing and pre-fabricated template strategies for non-invasive sensing of clozapine (CLZ) as an efficient substrate adsorption and electrocatalyst. The introduction of Co sub-nanoclusters (Co NCs) provides enhanced electrochemical performance and better substrate adsorption potential compared to porous and nitrogen-doped carbon structures. Combined with ab initio calculations, it is found that the favorable CLZ catalytic performance with C─N─Co NCs is mainly attributed to possessing a more stable CLZ adsorption structure and lower conversion barriers of CLZ to oxidized state CLZ. An electrochemical sensor for CLZ detection is conceptualized with a wide operating range and high sensitivity, with monitoring capabilities validated in a variety of body fluid environments. Based on the developed CLZ sensing system, the CLZ correlation between blood and saliva and the accuracy of the sensor are investigated by the gold standard method and the rat model of drug administration, paving the way for non-invasive drug monitoring. This work provides new insights into the development of efficient electrocatalysts to enable drug therapy and administration monitoring in personalized healthcare systems.

MSC converter with optimized input current ripple for fuel cells applications

This article focuses on the analysis of a newly introduced DC-DC converter structure suitable for applications in fuel cell generation systems, the Modified Series Capacitor (MSC) converter. An interleaved-type converter with high voltage gain. The converter was proposed with a particular PWM scheme in which their two transistors operate with equal duty cycle, but the switching signals are 180° out of phase, and it uses two equal inductors. This article suggests a different way to design and operate the MSC converter with unequal inductors and unequal duty cycles. The primary benefit of the proposed approach with independent duty cycles and inductances is that it allows for the application of a numerical optimization algorithm to minimize the converter's input current ripple without the need to increase the stored energy in inductors. For example, it was possible to reduce one of the two inductors while maintaining (or even improving) the power quality of the input current. To prove the concept, an experiment was set up, executed, and confirmed.

An evaluation of the Place Standard Tool as a means of examining inequalities in relation to place

ABSTRACT Improving the quality of places is a crucial element in addressing the inequalities that exist across the UK. While standardised tools exist to structure conversations about place, the extent to which these capture inequalities remain unclear. This study examined the utility of the Place Standard Tool (PST) as a means of understanding inequalities in relation to place. A dataset of 8,218 PST responses collected in the north of England, and the PST itself, were analysed using an inequalities lens with a particular focus on the qualitative data collected through the tool. The results showed that despite limits to the demographic data recorded by the PST such as the lack of ethnicity and disability data, key themes relating to protected characteristic groups were captured in the data. The analysis identified the themes of ethnicity, gender, physical mobility, economic status, and housing situation as particularly prominent within the dataset, and reflects on how these themes affect people’s relationships with place. In its current form, the PST demonstrates an ability to improve understanding of inequalities in relation to place. However, extra consideration, particularly relating to ensuring the PST is applied equitably, and some adaptation of questions would unlock its full potential. Improving the quality of demographic data collected is a key part of improving the accuracy and equity of data collection. Responding proactively to gaps in response rates during data collection exercises can improve the overall quality of data collected, particularly for minority groups. Considering equitable and accessible ways to collect data using the Place Standard Tool is key to fulfilling its potential as a tool for examining inequalities in relation to place.

Bridging Thai music notation to Western music scores through innovative conversion and evaluation

Research on bridging Thai music notation to Western music scores through innovative conversion and evaluation by developing a Thai music notation printing program through innovative research For converting Thai musical notation into an international musical score by researching documents and related research along with advice from music experts. After that, the program was tried and evaluated by three experts and 20 test users. The results of the research showed the creation of a program to Thai music notation to Western music note structure conversion called XxX Notation (Triple Note) by accessing the domain http://www.music.msu.ac.th/xxxnotation-v2, which is under the website of the College of Music, Mahasarakham University. Music can be saved online, reused, and edited. Able to export notes to paper through printers, PDF, Word, and Excel. Able to listen to the sound of printed notes. It is the sound of a large gong, which is an instrument in the main melody of Thai music. And can increase or decrease speed. To Thai music notation to Western music note structure conversion. Use Thai music notation input, convert the data to MusicXML, and display it as an international note. The results of the quality assessment of the Thai music notation printing program from 3 experts to evaluate the quality of the program in 4 aspects found that the program evaluation results were the highest quality with an average of 4.68, and the quality assessment results from 20 users were the highest quality with an average of 4.76.