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Wyniki wyszukiwania dla: CHIRAL DETERMINATION
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Chromium‑based metal organic framework for pipette tip micro‑solid phase extraction: an effective approach for determination of methyl and propyl parabens in wastewater and shampoo samples
PublikacjaAbstract Background A chromium-based metal organic framework was synthesized and employed as an efficient sorbent for pipette tip micro-solid phase extraction and preconcentration of parabens from wastewater and shampoo samples up to sub-ppb level before their spectrophotometric analysis. Results Factors affecting preconcentration including volume and type of solvent, amount of sorbent, number of extraction, and volume and pH of...
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Sensitive method for determination of benzoic acid in beverages and food samples using air–assisted hydrophobic deep eutectic solvent-based dispersive liquid-liquid microextraction
PublikacjaA simple, reliable and rapid air–assisted hydrophobic deep eutectic solvent-based dispersive liquid–liquid microextraction (AA-HDES-DLLME) was developed for analysis of benzoic acid in various beverages and food samples. The final determination stage was performed via UV–visible spectrophotometry. The key parameters (extraction time, HDES type and volume, dispersant volume, pH and sample volume) of the AA-HDES-DLLME method were...
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Volterra series usefulness in modelling of the time-domain cross-talk phenomena in coupled microstrip lines with nonlinear termination
PublikacjaW pracy przedyskutowano możliwość wykorzystania szeregów Volterry do analizy zjawiska przesłuchu w sprzężonych liniach mikropaskowych z nieliniowym obciążeniem. Apracowano algorytm metody, zaś uzyskane wyniki numeryczne zweryfikowano poprzez porównania z wynikami badań eksperymentalnych linii obciążonych w torze transmisyjnym diodą Schottky'ego.
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Stereoselective Alkylation of Indole with 5-Arylidene-Meldrum’s Acids in the Presence of Organocatalysts
PublikacjaBackground: Indole motif is frequently present in biologically active compounds. Enantiomerically pure or enriched 2,2-dimethyl-5-(aryl(1H-indol-3-yl)methyl)-1,3-dioxane-4,6-diones can be considered as a convenient starting point for the synthesis of a indole ring fused with cyclic ketones with biological activity. Preparation of chiral 2,2-dimethyl-5-(aryl(1H-indol-3-yl)methyl)-1,3-dioxane- 4,6-diones requires the reaction of...
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Determination of tributylotin (TBT) in marine sediment using pressurised liquid extraction-gas chromatography-isotope dilution mass spectrometry (PLE-GC-IDMS) with a hexane-tropolone mixture
PublikacjaOpracowano metodę oznaczania zawartości tributylocyny w próbkach osadu morskiego. Na etapie izolacji zastosowano technikę przyspieszonej ekstrakcji za pomocą roztworu tropolonu w heksanie.Na etapie oznaczeń końcowych wykorzystano technikę chromatografii gazowej, stosując metodę spektrometrii mas rozcieńczenia izotopowego. Wyznaczono parametry walidacyjne opracowanej metody: granicę wykrywalności, precyzję, poprawność i niepewność.
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Determination of tributyltin (TBT) in marine sediment using pressurised liquid extraction–gas chromatography–isotope dilution mass spectrometry (PLE–GC–IDMS) with a hexane–tropolone mixture
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A Comparative Quantitative Structure-Retention Relationships Study for Lipophilicity Determination of Compounds with a Phenanthrene Skeleton on Cyano-, Reversed Phase-, and Normal Phase-Thin Layer Chromatography Stationary Phases
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Correction to: Chromium‑based metal organic framework for pipette tip micro‑solid phase extraction: an effective approach for determination of methyl and propyl parabens in wastewater and shampoo samples
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PCN-222 metal–organic framework: a selective and highly efficient sorbent for the extraction of aspartame from gum, juice, and diet soft drink before its spectrophotometric determination
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Interference-Free Determination of Trace Copper in Freshly Ripened Honeys by Flame Atomic Absorption Spectrometry Following a Preconcentration by Solid-Phase Extraction and a Two-Step Elution Process
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Determination of phenol biodegradation pathways in three psychrotolerant yeasts, Candida subhashii A011, Candida oregonensis B021 and Schizoblastosporion starkeyi-henricii L012, isolated from Rucianka peatland
PublikacjaIn this study, three psychrotolerant phenol-degrading yeast strains Candida subhashii (strain A011), Candida oregonenis (strain B021) and Schizoblastosporion starkeyi-henricii (strain L012) isolated from Rucianka peatland were examined to determine which alternative metabolic pathway for phenol biodegradation is used by these microorganisms. All yeast strains were cultivated in minimal salt medium supplemented with phenol at 500,...
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Green, simple analytical method for biogenic amines determination in fruit juice samples using salting-out assisted liquid-liquid microextraction and gas chromatography-mass spectrometry
PublikacjaSalting-out assisted liquid-liquid microextraction (SALLME) was integrated with the derivatization procedure to establish a one-step sample pre-treatment approach for rapid analysis of 14 biogenic amines (BAs) in fruit juices. The methodology consists of salting-out of analytes, derivatization with ethyl chloroformate (ECF), extraction with ethyl acetate (EtAc), and the analysis of the derivatized BAs using gas chromatography-mass...
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Investigation of vortex assisted magnetic deep eutectic solvent based dispersive liquid–liquid microextraction for separation and determination of vanadium from water and food matrices: Multivariate analysis
PublikacjaA new and simple vortex assisted magnetic deep eutectic solvent dispersive liquid–liquid microextraction procedure (VA-MDES-DLLME) was developed for the determination of vanadium (V) in food and water samples by flame atomic absorption spectrometry (FAAS). In the extraction medium, a bis(acetylpivalylmethane) ethylenediimine (H2APM2en) was used for the complexation of V(V) in sample solution at pH 6. The VA-MDES-DLLME was optimized...
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Sulfur compounds: Gas chromatography
PublikacjaSulfur compounds, due to their properties, are responsible for the damage of our environment. For this reason sulfur containing compounds are of constant concern in many fields. Gas chromatography (GC), due to combination of separation capability and sensitive detection is a prime technique for the analysis of thes compounds in various matrices. The chapter rewies general problems of the determination of these compounds by GC and...
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Study on surface termination of boron-doped diamond electrodes under anodic polarization in H2SO4 by means of dynamic impedance technique
PublikacjaAnodic oxidation is a popular way to modify termination bonds at boron doped diamond electrodes altering their electrochemical and physicochemical properties. Our studies, performed with dynamic electrochemical impedance spectroscopy technique, supported with X-ray photoelectron spectroscopy and ellipsometry analysis prove its utility in continuous on-line monitoring of impedance changes on the electrode surface under polarization...
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Identification of X-DING-CD4, a new member of human DING protein family that is secreted by HIV-1 resistant CD4+ T cells and has anti-viral activity
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Application of Alanine Scanning to Determination of Amino Acids Essential for Peptide Adsorption at the Solid/Solution Interface and Binding to the Receptor: Surface-Enhanced Raman/Infrared Spectroscopy versus Bioactivity Assays
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Simultaneous determination of droxidopa and carbidopa by carbon paste electrode functionalized with NiFe2O4 nanoparticle and 2-(4-ferrocenyl-[1,2,3]triazol-1-yl)-1-(naphthalen-2-yl) ethanone
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Application of gas flow headspace liquid phase micro extraction coupled with gas chromatography-mass spectrometry for determination of 4-methylimidazole in food samples employing experimental design optimization
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The Mesoporous Porphyrinic Zirconium Metal-Organic Framework for Pipette-Tip Solid-Phase Extraction of Mercury from Fish Samples Followed by Cold Vapor Atomic Absorption Spectrometric Determination
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Coupling of cold vapor generation with an atmospheric pressure glow microdischarge sustained between a miniature flow helium jet and a flowing liquid cathode for the determination of mercury by optical emission spectrometry
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Magnetic hydrophobic deep eutectic solvents for orbital shaker-assisted dispersive liquid-liquid microextraction (MAGDES-OS-DLLME) - determination of nickel and copper in food and water samples by FAAS
PublikacjaIn this work, a cheap and widely applicable dispersive liquid-liquid microextraction (DLLME) method was developed for the extraction of Ni(II) and Cu(II) from water and food samples and analysis using flame atomic absorption spectrometry. DLLME was assisted by orbital shaker, while ferrofluid as an extractant was based on deep eutectic solvent (DES). This ferrofluid was made of hydrophobic DES (hDES), composed of lauric acid and...
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The presence of polycyclic aromatic hydrocarbons in disposable baby diapers: A facile determination method via salting-out assisted liquid-liquid extraction coupled with gas chromatography-mass spectrometry
PublikacjaIn this paper we demonstrate the development of the extraction procedure of polycyclic aromatic hy- drocarbons from baby diapers along with their quantification by gas chromatography-mass spectrometry. Apart from covering plastic foil, disposable baby diapers contain sorbents intended to absorb urine and feces. A hygroscopic, adsorptive, and tough-to-homogenize fibrous sorbent, represents an analytical chal- lenge to analytical...
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Uncertainty of Postmortem Time Estimation Based on Potassium Ion Determination in Vitreous Humor Using Potentiometric Ion-Selective Electrode and Microwave-Induced Plasma with Optical Emission Spectrometry Methods
PublikacjaThere is a need for a reliable and independent evaluation and confirmation of the post-mortem interval (PMI) based on objective factors other than only postmortem changes or temperature measurements. Estimating the PMI by examining the concentration of potassium ions in the vitreous humor (VH) has a tradition in forensic toxicology dating back to the mid-20th century. So far, the methods for determining the presence of potassium...
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Stability analysis of single-walled carbon nanotubes embedded in winkler foundation placed in a thermal environment considering the surface effect using a new refined beam theory
PublikacjaThis article is devoted to investigate the stability of different types of Single Walled Carbon Nanotubes (SWCNTs) such as zigzag, chiral, and armchair types which are rested in Winkler elastic foundations exposing to both the low and high temperature environments. Also, the Surface effects which include surface energy and surface residual stresses, are taken into consideration in this study. It may be noted that the surface energy...
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Does China use its trade potential in the Belt and Road Initiative properly? The relations between Chinese value added and trade potential in the European countries: bottom-up analysis
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Distinction of clenbuterol intake from drug or contaminated food of animal origin in a controlled administration trial – the potential of enantiomeric separation for doping control analysis
PublikacjaThe differentiation of clenbuterol abuse and unintentional ingestion by contaminated meat is crucial with respect to the valuation of an adverse analytical finding in human sports doping control. The proportion of the two enantiomers of clenbuterol may serve as potential discriminating parameter. For the determination of the individual enantiomers, specific methods were developed and validated for the different matrices under investigation...
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Oznaczanie stężeń jonów fluorkowych w próbkach wody pitnej z terenu miasta Malborka = Determination of fluoride ions in drinking water samples collected from the area of the town of Malbork
PublikacjaW pracy przedstawiono badania próbek wody pitnej z terenu miasta Malborka. Próbki wody pobierano sześciokrotnie (w miesięcznych odstępach - październik 2008, listopad 2008, grudzień 2008, styczeń 2009, luty 2009 oraz marzec 2009) w siedmiu punktach leżących w głównych dzielnicach miasta Malborka. Pobrane próbki podano analizie w celu oznaczenia następujących parametrów: zawartość anionów: F-, Cl-, Br-, 2NO , 3NO , 34 PO , 24 SO...
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Application of Box-Behnken design in response surface methodology for the molecularly imprinted polymer pipette-tip solid phase extraction of methyl red from seawater samples and its determination by spectrophotometery
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Synthesis, characterization and application of a zirconium-based MOF-808 functionalized with isonicotinic acid for fast and efficient solid phase extraction of uranium(VI) from wastewater prior to its spectrophotometric determination
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Separation and determination of ciprofloxacin in seawater, human blood plasma and tablet samples using molecularly imprinted polymer pipette‐tip solid phase extraction and its optimization by response surface methodology
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Rapid and simple multi-analyte LC–MS/MS method for the determination of benzodiazepines and Z-hypnotic drugs in blood samples: Development, validation and application based on three years of toxicological analyses
PublikacjaBenzodiazepines (BZDs) and Z-drugs have been particularly important treatments for sleeping and anxiety disorders for many years. However, recently, a number of new benzodiazepines (named designer benzodiazepines, DBZDs) were synthesised, but some of them have never been used in the clinic; they reached the black drug market as new psychoactive substances and are used for recreational purposes. The abuse of these substances has...
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Horizontal velocity field derived from EPN and ASG-EUPOS satellite data on the example of south-western part of Poland
PublikacjaPresently the determination of the velocity field in the global reference frame is possible by using different space techniques and dense terrestrial networks from global to local and regional scales. However, the reliability of such determinations is strongly limited by the restricted number of unmodeled effects. Some of them are periodic (atmospheric or hydrological effects), some instantaneous (natural or man-made seismicity)...
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Determination of volatile fatty acids in municipal wastewater and leachates from sewage sludge allotments and compost piles using direct aqueous injection gas chromatography preceded by distillation based sample cleanup
PublikacjaOpracowano metodykę i wykorzystano ją do oznaczania lotnych kwasów tłuszczowych w zanieczyszczonych próbkach wodnych,takich jak ścieki komunalne, odcieki ze składowiska osadów ściekowych i pryzm kompostu, stosując metodę bezpośredniego dozowania rzeczywistej próbki wodnej lub jej rektyfikatu do chromatografu gazowego.
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Comments on Identification and Determination of Volatile Chloroorganic Compounds in Crude Oil at Trace Level = Komentarz na temat identyfikowania i oznaczania śladowych ilości lotnych związków chloroorganicznych w ropie naftowej
PublikacjaW pracy przedstawiono możliwości i ograniczenia w stosowaniu techniki GC-ECD i GC-MS do identyfikacji i oznaczania śladowych stężeń związków chloroorganicznych w destylatach z ropy naftowej (frakcjach wrzących do 200oC). Przedyskutowano także procedury rutynowo stosowane w rafineriach do oznaczania zawartości chloru organicznego. Należą do nich metodyki oparte na spalaniu próbki i oznaczaniu wybranych produktów mineralizacji za...
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Wyznaczenie optymalnego sposobu eksploatacji ujęć za pomocą modelu numerycznego na przykładzie rejonu Słupska = Determination of the optimal way of the exploitation based on the numerical model - case study Słupsk region
PublikacjaRejon Słupska należy do obszarów o korzystnych lecz skomplikowanych warunkach hydrogeologicznych. W neogeńskim poziomie wodonośnym wyróżnia się dwie warstwy wodonośne, przy czym obie narażone są na możliwość zasolenia w wyniku ascenzji wód piętra kredowego. Ze względu na planowane zaopatrzenie w wodę miasta Słupska wyłącznie w oparciu o ujęcia Westerplatte i Głobino, badaniami objęto przybliżony obszar zasilania i oddziaływania...
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Spectroscopic evaluation of a low power atmospheric pressure mixed argon–helium microwave induced plasma combined with the chemical generation of volatile species for the optical emission spectrometric determination of arsenic, antimony and mercury
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Opracowanie procedury oznaczania lotnych produktów utleniania olejów roślinnychtechniką statycznej analizy fazy nadpowierzchniowej = The development of a new procedure for determination of volatile oxidation products in edible oils with the use of static headspace analysis
PublikacjaW publikacji przedstawiono dobór optymalnych parametrów w celu opracowania nowej metody diagnozowania jakości olejów poprzez oznaczenie lotnych związków będących produktami reakcji utleniania olejów. Próbki rafinowanych olejów roślinnych przed analizą poddano procesowi przyspieszonego utleniania, stosując naświetlanie promieniowaniem ultrafioletowym (12 W, 254 nm). Jako technikę ekstrakcji lotnej frakcji próbki zastosowano statyczną...
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Box-Behnken design optimization of pipette tip solid phase extraction for methyl orange and acid red determination by spectrophotometry in seawater samples using graphite based magnetic NiFe2O4 decorated exfoliated as sorbent
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FLAME ATOMIC ABSORPTION SPECTROMETRIC DETERMINATION OF TRACE AMOUNTS OF SILVER IN RADIOLOGICAL WASTE SAMPLES AFTER SOLID PHASE EXTRACTION USING MULTI-WALLED CARBON NANO-TUBES MODIFIED BY SODIUM DODECYL SULFATE
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Synthesis and biological activity of mycophenolic acid-amino acid derivatives
PublikacjaIn search of new immunosuppressants, mycophenolic acid (MPA) was coupled with amino acid methyl esters followed by hydrolysis to analogs bearing free carboxylic groups. The obtained compunds were tested in vitro as growth inhibitors of lymphoid cell line (Jurkat) and human peripheral blood mononuclear cells (PBMC) from healthy donors. According to obtained results recovering of free carboxylic group increased their activity. Additionally,...
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Comparative Analysis of Metabolic Variations, Antioxidant Profiles and Antimicrobial Activity of Salvia hispanica (Chia) Seed, Sprout, Leaf, Flower, Root and Herb Extracts
PublikacjaThe purpose of this study was to evaluate the phytochemical profiles of the seeds, sprouts, leaves, flowers, roots and herb of Salvia hispanica and to demonstrate their significant contribution to antioxidant and antimicrobial activities. Applied methods were: HPLC-DAD coupled with post-column derivatization with ABTS reagent, untargeted metabolomics performed by LC-Q-Orbitrap HRMS, and two-fold micro-dilution broth method, which...
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“Dilute & Shoot” approach for rapid determination of trace amounts of nicotine in zero-level e-liquids by reversed phase liquid chromatography and hydrophilic interactions liquid chromatography coupled with tandem mass spectrometry-electrospray ionization
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Development of a solventless stir bar sorptive extraction/thermal desorption large volume injection capillary gas chromatographic-mass spectrometric method for ultra-trace determination of pyrethroids pesticides in river and tap water samples
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Application of Box–Behnken design in the optimization of a simple graphene oxide/zinc oxide nanocomposite-based pipette tip micro-solid phase extraction for the determination of Rhodamine B and Malachite green in seawater samples by spectrophotometry
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HR-CS FAAS based method for direct determination of total concentrations of Ca, Fe, Mg and Mn in functional apple beverages and evaluation of contributions of the bioaccessible fraction of these elements by in vitro gastrointestinal digestion and chemical fractionation
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Solid-contact lead(II) ion-selective electrodes for potentiometric determination of lead(II) in presence of high concentrations of Na(I), Cu(II), Cd(II), Zn(II), Ca(II) and Mg(II)
PublikacjaLead and its compounds are a serious threat to the environment. Monitoring of this toxic heavy metal is a driving force for the continuous development of novel lead(II) ionophores to be applied in ion-selective electrodes. In this work a highly selective lead(II) ionophore, namely 25,26,27,28-tetrakis(piperidinylthiocarbonylmethylene)-p-tert-butylcalix[4]arene, was used in solid-contact ion-selective electrodes for determination...
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Fast, sensitive and reliable multi-residue method for routine determination of 34 pesticides from various chemical groups in water samples by using dispersive liquid – liquid microextraction coupled with gas chromatography – mass spectrometry
PublikacjaA simple and efficient dispersive liquid-liquid microextraction technique (DLLME) was developed by using a mixture of two solvents: 40 μL of tetrachlorethylene (extraction solvent) and 1.0 mL of methanol (disperser solvent), which was rapidly injected with a syringe into 10mL ofwater sample. Some important parameters affecting the extraction efficiency, such as type and volume of solvents, water sample volume, extraction time,...
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“Dilute & Shoot” approach for rapid determination of trace amounts of nicotine in zero-level e-liquids by reversed phase liquid chromatography and hydrophilic interactions liquid chromatography coupled with tandem mass spectrometry-electrospray ionization
PublikacjaTwo analytical procedures are proposed where HILIC and RPLC techniques are coupled with tandem mass spectrometry detection for rapid determination of trace amounts of nicotine in zero-level liquids for electronic cigarettes. Samples are prepared on the basis of the approach “dilute & shoot” which makes this important step quick and not complicated. The chromatographic separation was carried out on a Zorbax XDB column (RPLC method)...
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Potential Skyrmion Host Fe(IO3)3: Connecting Stereoactive Lone-Pair Electron Effects to the Dzyaloshinskii-Moriya Interaction
PublikacjaMagnetic skyrmions, which are topologically distinct magnetic spin textures, are gaining increased attention for their unique physical properties and potential applications in spintronic devices. Here we present a design strategy for skyrmion host candidates based on combinations of magnetic spin, asymmetric building units having stereoactive lone-pair electrons, and polar lattice symmetry. To demonstrate the viability of the proposed...