Artykuły w czasopismach: „Complexe ZZS”

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Dais, Tyson N., Rina Takano, Takayuki Ishida i Paul G. Plieger. "Lanthanide induced variability in localised Co^II geometries of four triangular L₃Co₃^IILn^III complexes". RSC Advances 12, nr 8 (2022): 4828–35. http://dx.doi.org/10.1039/d1ra08797e.

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Four acyclic CoII–3LnIII triangle complexes are reported in which two Co ions in each complex are octahedral while the third Co exhibits a lanthanide dependent coordination geometry. Magnetic analysis of the La complex shows a large ZFS effect for Co.

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Jiang, Heng, Jie Zhang, Yibo Zeng, Yanli Chen, Hang Guo, Lei Li, Xin Chen i Ying Zhang. "Two-dimensional ZnS@N-doped carbon nanoplates for complete lithium ion batteries". Nanotechnology 33, nr 6 (18.11.2021): 065406. http://dx.doi.org/10.1088/1361-6528/ac3540.

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Abstract Metal sulfides are promising anode materials for lithium ion batteries because of the high specific capacities and better electrochemical kinetics comparing to their oxide counterparts. In this paper, novel monocrystalline wurtzite ZnS@N-doped carbon (ZnS@N–C) nanoplates, whose morphology and phase are different from the common ZnS particles with cubic phase, are successfully synthesized. The ZnS@N–C nanoplates exhibit long cycle life with a high reversible specific capacity of 536.8 mAh · g−1 after 500 cycles at a current density of 500 mA · g−1, which is superior to the pure ZnS nanoplates, illustrating the obvious effect of the N-doped carbon coating for mitigating volume change of the ZnS nanoplates and enhancing the electronic conductivity during charge/discharge processes. Furthermore, it is revealed that the ZnS single crystals with wurtzite phase in the ZnS@N–C nanoplates are transformed to the polycrystalline cubic phase ZnS after charge/discharge processes. In particular, the ZnS@N–C nanoplates are combined with the commercial LiNi0.6Co0.2Mn0.2O2 cathode to fabricate a new type of LiNi0.6Co0.2Mn0.2O2/ZnS@N–C complete battery, which exhibits good cycling durability up to 120 cycles at a charge/discharge rate of 1 C after the prelithiation treatment on the ZnS@N–C anode, highlighting the potential of the ZnS@N–C nanoplates anode material applied in lithium ion battery.

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Onwudiwe, Damian C., Jerry O. Adeyemi, Rebecca T. Papane, Felicia F. Bobinihi i Eric Hosten. "Synthesis, optical and structural characterisation of ZnS nanoparticles derived from Zn(ii) dithiocarbamate complexes". Open Chemistry 19, nr 1 (1.01.2021): 1134–47. http://dx.doi.org/10.1515/chem-2021-0094.

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Abstract Zinc sulphide nanoparticles represented as ZnS1, ZnS2 and ZnS3 have been prepared from Zn(ii) N-methyl-N-ethanoldithiocarbamate (1) complex and its 2,2′-bipyridine (2) and 1,10′-phenanthroline (3) adducts, respectively. Both the parent complex (1) and the adducts (2) and (3) were characterised by spectroscopic techniques and elemental analysis. In the solid state, the structures of complexes (1) and (2) were established using single-crystal X-ray analysis. Complex (1) possessed a distorted trigonal bipyramidal geometry about the zinc centre, whilst forming a dimer via bidentate bridging coordination between two opposite dithiocarbamate motifs. On the other hand, complex (2) formed a trigonal prismatic geometry about the Zn centre with a ZnS4N2 chromophore. The decomposition of the complexes in hexadecylamine afforded spherical-shaped ZnS nanoparticles of the cubic sphalerite crystal phase. The transmission electron microscopy (TEM) micrographs showed that the average particles size of ZnS1, ZnS2 and ZnS3 were 2.63, 5.27 and 6.52 nm, respectively. In the optical study, the estimated bandgap energies were found in the range between 4.34 and 4.08 eV, which indicated a blue shift when compared with the bandgap energy of bulk ZnS.

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Bentley, Blake, Fadi Chanaa i Steven Clayton. "Complete Esophageal Obstruction: A Rare Complication of Zollinger-Ellison Syndrome". ACG Case Reports Journal 10, nr 11 (listopad 2023): e01205. http://dx.doi.org/10.14309/crj.0000000000001205.

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ABSTRACT Complete esophageal obstruction (CEO) is a rare phenomenon usually observed after receiving head and neck radiation. Zollinger-Ellison syndrome (ZES) is typically associated with minimal esophageal morbidity because of advancements in antisecretory medications. There are currently no documented reports of CEO in patients with ZES. Although surgeries are available for the treatment of CEO, there is no established method for endoscopic lumen restoration, given its rarity. This case documents potential sequala of modern-day patients with ZES.

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Corti, Fabio, Alberto Reatti, Ya-Hui Wu, Dariusz Czarkowski i Salvatore Musumeci. "Zero Voltage Switching Condition in Class-E Inverter for Capacitive Wireless Power Transfer Applications". Energies 14, nr 4 (9.02.2021): 911. http://dx.doi.org/10.3390/en14040911.

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This paper presents a complete design methodology of a Class-E inverter for capacitive wireless power transfer (CWPT) applications, focusing on the capacitance coupling influence. The CWPT has been investigated in this paper, because most of the literature refers to inductive power transfer (IWPT). However, CWPT in perspective can result in lower cost and higher reliability than IWPT, because it does not need coils and related shields. The Class-E inverter has been selected, because it is a single switch inverter with a grounded MOSFET source terminal, and this leads to low costs and a simple control strategy. The presented design procedure ensures both zero voltage switching (ZVS) and zero derivative switching (ZDS) conditions at an optimum coupling coefficient, thus enabling a high transmission and conversion efficiency. The novelties of the proposed method are that the output power is boosted higher than in previous papers available in the literature, the inverter is operated at a high conversion efficiency, and the equivalent impedance of the capacitive wireless power transfer circuit to operate in resonance is exploited. The power and the efficiency have been increased by operating the inverter at 100 kHz so that turn-off losses, as well as losses in inductor and capacitors, are reduced. The closed-form expressions for all the Class-E inverter voltage and currents waveforms are derived, and this allows for the understanding of the effects of the coupling coefficient variations on ZVS and ZDS conditions. The analytical estimations are validated through several LTSpice simulations and experimental results. The converter circuit, used for the proposed analysis, has been designed and simulated, and a laboratory prototype has been experimentally tested. The experimental prototype can transfer 83.5 W at optimal capacitive coupling with operating at 100 kHz featuring 92.5% of the efficiency, confirming that theoretical and simulation results are in good agreement with the experimental tests.

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Смагин, В. П., Л. В. Затонская, Е. Г. Ильина i Е. П. Харнутова. "Фотолюминесценция композиций полиметилметакрилат/(Zn, Cu, Ag)S : Eu-=SUP=-3+-=/SUP=-". Физика твердого тела 62, nr 7 (2020): 1074. http://dx.doi.org/10.21883/ftt.2020.07.49476.037.

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Luminescent nanoscale particles (quantum dots) (Zn,Cu,Ag)S:Eu3+ were synthesized during decomposition of thioacetamide complexes of metals in a methylmethacrylate medium during block polymerization under heating. The formation of quantum dots is confirmed by the corresponding band in the optical absorption spectrum of polymer compositions. Photoluminescence of PMMA/(Zn,Cu,Ag)S:Eu3+ compositions is manifested as a complex band associated with defects in the crystal structure formed when ZnS was doped with copper and silver ions, and a set of narrow bands of luminescence of Eu3+ ions. Luminescence excitation occurs as a result of inter-zone transitions and electron transitions from the valence band to the ZnS defect levels, and self-absorption of energy by Eu3+ ions. The relationship of ions Eu3+ particles of ZnS is confirmed by the dependence of the intensity of the broadband luminescence of ZnS with increasing concentration of ions Eu3+ and an increase in intensity narrow-band luminescence of ions Eu3+ as a result of energy transfer from levels of doped ZnS crystals on the energy levels of the ions Eu3+.

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Martynenko, Irina V., Anna O. Orlova, Vladimir G. Maslov, Alexander V. Baranov, Anatoly V. Fedorov i Mikhail Artemyev. "Energy transfer in complexes of water-soluble quantum dots and chlorin e6 molecules in different environments". Beilstein Journal of Nanotechnology 4 (13.12.2013): 895–902. http://dx.doi.org/10.3762/bjnano.4.101.

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The photoexcitation energy transfer is found and investigated in complexes of CdSe/ZnS cationic quantum dots and chlorin e6 molecules formed by covalent bonding and electrostatic interaction in aqueous solution and in porous track membranes. The quantum dots and chlorin e6 molecules form stable complexes that exhibit Förster resonance energy transfer (FRET) from quantum dots to chlorin e6 regardless of complex formation conditions. Competitive channels of photoexcitation energy dissipation in the complexes, which hamper the FRET process, were found and discussed.

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Halaš, Petr, Ivan Nemec i Radovan Herchel. "Honey-like Odor Meets Single-Ion Magnet: Synthesis, Crystal Structure, and Magnetism of Cobalt(II) Complex with Aromatic Trans-Cinnamic Acid". Magnetochemistry 9, nr 11 (16.11.2023): 229. http://dx.doi.org/10.3390/magnetochemistry9110229.

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The hexacoordinate Co(II) complex [Co(neo)2(cin)][BPh4]·½Me2CO (1·½Me2CO) containing trans-cinnamic acid (Hcin) and neocuproine (neo) was prepared. The compound 1·½Me2CO was characterized via single-crystal X-ray analysis, FT-IR spectroscopy, and magnetic measurements. The coordination polyhedron of the complex cation adopts a deformed octahedron shape, and cinnamate exhibits a bidentate mode of coordination, which is unusual for mononuclear Co(II) cinnamate complexes. The analysis of DC magnetic measurements with zero-field splitting (ZFS) spin Hamiltonian revealed large magnetic anisotropy defined by the axial ZFS parameter D = +53.2 cm−1. AC susceptibility measurements revealed the slow relaxation of magnetization under the applied field; thus, 1·½Me2CO behaves as a field-induced single-molecule magnet. The analysis of magnetic properties was also supported by CASSCF/NEVPT2 calculations.

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Chakraborty, Avijit, Pradip Kumar Sadhu, Kallol Bhaumik, Palash Pal i Nitai Pal. "Behaviour of a High Frequency Parallel Quasi Resonant Inverter Fitted Induction Heater with Different Switching Frequencies". International Journal of Electrical and Computer Engineering (IJECE) 6, nr 2 (1.04.2016): 447. http://dx.doi.org/10.11591/ijece.v6i2.pp447-457.

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This paper investigates the behavior of a high frequency parallel quasiresonant inverter fitted domestic induction heater with different switching frequencies. The power semiconductor switch Insulated Gate Bipolar Junction Transistor (IGBT) is incorporated in this high frequency inverter that can operate under ZVS and ZCS conditions during the switching operations at certain switching frequency to reduce switching losses. The proposed induction heating system responds to three different switching frequencies with providing different results. An Insulated Gate Bipolar Junction Transistor (IGBT) provides better efficiency and faster switching operations. After the complete study of the proposed induction heating system at the selected switching frequencies, the results are compared and it is decided that most reliable, efficient and effective operations from the proposed induction heater can be obtained if the switching frequency is selected slightly above the resonant frequency of the tank circuit of the resonant inverter. The proposed scheme is analyzed using Power System Simulator (PSIM) environment.

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Ernits, K., K. Muska, M. Danilson, J. Raudoja, T. Varema, O. Volobujeva i M. Altosaar. "Anion Effect of Zinc Source on Chemically Deposited ZnS(O,OH) Films". Advances in Materials Science and Engineering 2009 (2009): 1–5. http://dx.doi.org/10.1155/2009/372708.

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The study on the anion effect of different Zn sources—Zn(CH3COO)2, ZnCl2, ZnI2, Zn(NO3)2and ZnSO4—on the chemical deposition of ZnS(O,OH) films revealed that the growth rate and composition of the ZnS(O,OH) layer depend on the instability constant (pK) value of the corresponding Zn-complex Zn(L)nin the chemical bath solution. In the region ofpKZn(NH3)2+>pKZn(L)nthe ZnS(O,OH) film's growth rate and ZnS concentration in films increased with the increasing pK value of the used Zn salt complex up to the pK value of theZn[NH3]2+complex and decreased in the region wherepKZn(NH3)2+<pKZn(L)n. The band gap values (around 3.6 eV in most cases) of deposited ZnS(O,OH) films did not depend on the Zn precursor's instability constant, the ZnS(O,OH) film from zinc nitrate containing bath has higher band gap energy (Eg= 3.8 eV). The maximum efficiency of CISSe and CZTSSe monograin layer solar cells was gained with ZnS(O,OH) buffer layer deposited from CBD solution containing Zn(CH3COO)2as Zn source, which provided the highest growth rate and ZnS concentration in the ZnS(O,OH) film on glass substrates.

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Rai, S., i R. Kothari. "Synthesis and Spectroscopic Characterization of Zinc Sulphide nanoparticles using Microwave irradiation of Zinc complex of Thiosemicarbazone ligand as a Single Molecular precursor : Pharmacological activities". Digest Journal of Nanomaterials and Biostructures 18, nr 1 (styczeń 2023): 31–45. http://dx.doi.org/10.15251/djnb.2023.181.31.

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Single molecular precursors are appropriate starting materials for synthesis of semiconductor nanoparticles (NPs), which allow for the control of atomic ratio, monodispersity, composition and particle size of nanoscaled metallic sulfide nanoparticles. In the present study, we have reported the synthesis of nanostructured chalcogenides pharmacologically active active zinc sulfide nanoparticles (ZnS NPs) using Zn (II) ion inserted thiosemicarbazone ligand as a single molecular precursor .The precursors were thermally pyrolysized using high energy microwave radiations to obtain very fine ZnS nanoparticles. In this synthesis, we use DMSO as a nonpolar solvent for the synthesis of all compounds. The heating of Zinc complex in the non- aqueous environment of DMSO plays a very crucial role in decreasing reaction time, reducing the chances of side reactions and proper conversion of Zn complex into ZnS nanoparticles. In this reaction Zn complex of thiosemicarbazone ligand provides both Zn2+ and S2- ions for synthesis of ZnS nanoparticles. The microwave synthesis of ZnS NPs from Zn complex is a very simple, fast, highly effective, efficient and low cost method. All synthesized compounds were characterized by various structural, electronic, vibrational, optical, morphological and pharmacological characterizations. The prepared ZnS NPs were found to crystallize in cubic phase, which generally forms at low temperatures, with the dimensions dependent upon the molar ratio of molecular precursors used. Synthesized ZnS nanomaterials had surface sulfur vacancies that extend their absorption spectra towards the visible region and decreased the bond gap. This allowed ZnS nanoparticles to demonstrate various pharmacological activities like antibacterial, antioxidant and anti-inflammatory activities under normal conditions. Powered X-ray diffraction studies confirms the formation of well -defined equispaced crystalline ZnS NPS. TEM and FE SEM microscopic studies confirmed the elongated tubules structure of ZnS NPs with an average particle size of 60 nm. Sharpe electronic absorption band at 390 nm indicates the synthesis of good quality ZnS NPs. The FT-IR spectral studies confirmed the presence of Zn-S stretching, N-H bending and C=N stretching, vibrations in molecular precursor as Zn(II) complex. The thermal analysis of molecular precursor was performed to investigate the thermal stability of zinc complex. The Zn complex was stable up-to 3800 c. All synthesized compounds demonstrated excellent pharmacological activities like antibacterial, antioxidant and antiinflammatory activities as compared to standards used in analysis of compounds. The microwave synthesis of ZnS nanoparticles via single molecular precursor in proper stoichiometric ratios is an excellent and an efficient method for synthesizing highly effective bioactive agents which can be considered as good drug candidate for the treatment of various diseases in future

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Bédard, Mikaël, Vincent Roy, Martin Montagne i Pierre Lavigne. "Structural Insights into c-Myc-interacting Zinc Finger Protein-1 (Miz-1) Delineate Domains Required for DNA Scanning and Sequence-specific Binding". Journal of Biological Chemistry 292, nr 8 (29.12.2016): 3323–40. http://dx.doi.org/10.1074/jbc.m116.748699.

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c-Myc-interacting zinc finger protein-1 (Miz-1) is a poly-Cys2His2 zinc finger (ZF) transcriptional regulator of many cell cycle genes. A Miz-1 DNA sequence consensus has recently been identified and has also unveiled Miz-1 functions in other cellular processes, underscoring its importance in the cell. Miz-1 contains 13 ZFs, but it is unknown why Miz-1 has so many ZFs and whether they recognize and bind DNA sequences in a typical fashion. Here, we used NMR to deduce the role of Miz-1 ZFs 1–4 in detecting the Miz-1 consensus sequence and preventing nonspecific DNA binding. In the construct containing the first 4 ZFs, we observed that ZFs 3 and 4 form an unusual compact and stable structure that restricts their motions. Disruption of this compact structure by an electrostatically mismatched A86K mutation profoundly affected the DNA binding properties of the WT construct. On the one hand, Miz1–4WT was found to bind the Miz-1 DNA consensus sequence weakly and through ZFs 1–3 only. On the other hand, the four ZFs in the structurally destabilized Miz1–4A86K mutant bound to the DNA consensus with a 30-fold increase in affinity (100 nm). The formation of such a thermodynamically stable but nonspecific complex is expected to slow down the rate of DNA scanning by Miz-1 during the search for its consensus sequence. Interestingly, we found that the motif stabilizing the compact structure between ZFs 3 and 4 is conserved and enriched in other long poly-ZF proteins. As discussed in detail, our findings support a general role of compact inter-ZF structures in minimizing the formation of off-target DNA complexes.

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Rinke, Sven, Matthias Rödiger, Dirk Ziebolz i Anne-Kathrin Schmidt. "Fabrication of Zirconia-Reinforced Lithium Silicate Ceramic Restorations Using a Complete Digital Workflow". Case Reports in Dentistry 2015 (2015): 1–7. http://dx.doi.org/10.1155/2015/162178.

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This case report describes the fabrication of monolithic all-ceramic restorations using zirconia-reinforced lithium silicate (ZLS) ceramics. The use of powder-free intraoral scanner, generative fabrication technology of the working model, and CAD/CAM of the restorations in the dental laboratory allows a completely digitized workflow. The newly introduced ZLS ceramics offer a unique combination of fracture strength (>420 MPa), excellent optical properties, and optimum polishing characteristics, thus making them an interesting material option for monolithic restorations in the digital workflow.

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Torić, Filip, Gordana Pavlović, Damir Pajić, Marina Cindrić i Krešo Zadro. "Tetranuclear Ni4 cubane complexes with high χT maxima: magneto-structural analysis". CrystEngComm 20, nr 27 (2018): 3917–27. http://dx.doi.org/10.1039/c8ce00566d.

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Ajibade, Peter A., i Abimbola E. Oluwalana. "Photocatalytic Degradation of Single and Binary Mixture of Brilliant Green and Rhodamine B Dyes by Zinc Sulfide Quantum Dots". Molecules 26, nr 24 (19.12.2021): 7686. http://dx.doi.org/10.3390/molecules26247686.

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We present the preparation of octadecylamine-capped ZnS quantum dots from bis(morpholinyldithiocarbamato)Zn(II) complex. The complex was thermolyzed at 130 °C in octadecylamine at different times, to study the effect of reaction time on the morphological and photocatalytic properties of the ZnS quantum dots. Powder X-ray diffraction patterns confirmed a hexagonal wurtzite crystalline phase of ZnS, while HRTEM images showed particle sizes of about 1–3 nm, and energy band gaps of 3.68 eV (ZnS–1), 3.87 eV (ZnS–2), and 4.16 eV (ZnS–3) were obtained from the Tauc plot for the ZnS nanoparticles. The as-prepared ZnS were used as photocatalysts for the degradation of brilliant green, rhodamine B, and binary dye consisting of a mixture of brilliant green-rhodamine B. The highest photocatalytic degradation efficiency of 94% was obtained from ZnS–3 with low photoluminescence intensity. The effect of catalytic dosage and pH of the dyes solution on the photocatalytic process shows that pH 8 is optimal for the degradation of brilliant green, while pH 6.5 is the best for photocatalytic degradation of rhodamine B. The degradation of the binary dyes followed the same trends. The effect of catalytic dosage shows that 1 mg mL−1 of the ZnS nano-photocatalyst is the optimum dosage for the degradation of organic dyes. Reusability studies show that the ZnS quantum dots can be reused five times without a significant reduction in degradation efficiency.

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Xu, Leilei, Yuwei Ao, Bin Guan, Yun Xiang i Jianguo Guan. "Coordination Complex Transformation-Assisted Fabrication for Hollow Chestnut-Like Hierarchical ZnS with Enhanced Photocatalytic Hydrogen Evolution". Nanomaterials 9, nr 2 (15.02.2019): 273. http://dx.doi.org/10.3390/nano9020273.

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Hierarchical nanostructures (HNs) are possibly endowed with novel properties due to their complex three-dimensional (3D) structures. Here, we provide a novel stepwise growth strategy of Coordination Complex Transformation-Assisted Growth for fabricating HNs. By using this, we prepare a new wurtzite ZnS HNs-hollow chestnut-like hierarchical microspheres (HCHMs), which are mesoporous hollow microspheres with single crystalline nanorods arrayed densely and radially from the centre. The HCHMs formation depends on the stepwise decomposition of the two Zn2+ complexes ([Zn(en)m(H2O)2(3−m)]2+ and [Zn(en)m(NH3)2(3−m)]2+, natural number m < 3). As the reaction proceeds, [Zn2+] has been distinctly reduced due to the transformation from [Zn(en)m(H2O)2(3−m)]2+ to [Zn(en)m(NH3)2(3−m)]2+ with a high stability constant, leading to a low crystal growth rate to obtain single crystalline nanorods. Additionally, the generated bubbles (CO2, NH3) acting as a template can induce the generation of hollow structure. The as-prepared ZnS HCHMs show an enhanced photocatalytic hydrogen evolution activity due to the single crystalline wurtzite phase and the high surface area contributed by the hollow hierarchical structures, as well as the mesoporosity. The versatility of the coordination complex transformation-assisted growth strategy will open up new possibilities for fabricating HNs, especially for those transition metal ions with excellent complex capabilities.

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Shang, Jin, Huan Ke, Shu Wang Duo, Ting Zhi Liu i Hao Zhang. "Effect of Different Radios of Two Complexes on the Structural and Optical Properties of ZnS Thin Films". Advanced Materials Research 986-987 (lipiec 2014): 47–50. http://dx.doi.org/10.4028/www.scientific.net/amr.986-987.47.

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ZnS thin films were deposited at three different radios of V(NH3·H2O)/V(N2H4) on glass substrates by chemical bath deposition (CBD) method without stirring the deposition bath during the deposition process. The structural and optical properties were analyzed by X-ray diffraction (XRD) and UV-VIS spectrophotometer. The results showed that ZnS thin film deposited at the radio of V(NH3·H2O)/V(N2H4)=15:15 is higher than that of the other two different solutions. With the radio of V(NH3·H2O)/V(N2H4) decreasing from 15:5 to 15:15, homogenous precipitation of Zn (OH)2easily forms in the bath, but ZnS precipitation first become suppressed and then easily forms in solution. It means that the concentration of OH-ion increases with the volume of N2H4increasing, which accelerates the formation of Zn (OH)2. However, when the volume of N2H4increases to 15mL, relatively high concentration of OH-ion not only accelerates the formation of Zn (OH)2, but also be used to the hydrolysis of thiourea. The average transmissions of all the ZnS films from three different solutions (V(NH3·H2O)/V(N2H4)=15:5, 15:10 and 15:15) are greater than 90% for wavelength values in visible region. The direct band gaps range from 3.80 to 4.0eV. The ZnS film deposited for 2.5h with the radio of V(NH3·H2O)/V(N2H4)=15:15 has the cubic structure only after single deposition.

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Shilovskikh, O. V., V. O. Ponomarev, V. N. Kazaykin, K. A. Tkachenko, A. S. Vokhmintsev, I. A. Weinstein, S. M. Rozanova, M. V. Kirf i S. V. Marysheva. "Evaluation of the Anti-Infectious Activity of the Complex Based on Quantum Dots InP / ZnSe / ZnS 650 and Tobramycin Against Pseudomonas Aeruginosa Infection of the Cornea. Experimental Research". Ophthalmology in Russia 20, nr 1 (6.04.2023): 157–64. http://dx.doi.org/10.18008/1816-5095-2023-1-157-164.

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Microbial keratitis (MK) is a homogeneous group of diseases accompanied by loss of the corneal epithelium, stromal leukocyte infiltration and/or destructive tissue breakdown, occurring when the protective mechanisms of the ocular surface are disturbed, which require an immediate set of therapeutic measures, including, first of all, massive etiotropic therapy, which is represented, as a rule, by broad-spectrum antibiotics (AB) and anti-inflammatory drugs. One of the most threatening MK pathogens is P. aeruginosa (PA) (Pseudomonas aeruginosa). Multiple drug resistance, the highest pathogenicity, numerous RA virulence factors dictate the need to search for new highly effective methods to combat MC, in the etiological structure of which RA dominates. The most promising direction in this area is the use of artificial fluorophores, in particular quantum dots (QDs). The objective of this study was to evaluate the anti-infectious activity of the complex based on InP/ZnSe/ZnS 650 quantum dots and Tobramycin against Pseudomonas aeruginosa infection of the cornea. As an object of study, laboratory New Zealand rabbits (No. 6) were studied — 2 females, 4 males, which were induced bacterial keratitis by introducing a nosocomial Ps strain. aeruginosa in the structure of the cornea. The following antimicrobial agents were used: Tobramycin solution 5 ml for epibulbar application and a bioconjugate based on QD InP/ZnSe/ZnS 650 and tobramycin. Laboratory animals were divided into 2 groups. Rabbits of the 1st group, after the manifestation of the clinical picture of microbial keratitis, received instillations of tobramycin drops into the conjunctival sac every 2 hours for 3 days with a complete absence of positive clinical dynamics and a subsequent transition from day 4 in order to anatomically preserve the eyeball to instillations of the CT InP/ZnSe/ZnS complex 650 + Tobramycin. Rabbits of the 2nd group received instillations of the CT + Tobramycin complex and showed positive dynamics in relation to the regression of symptoms from the 2nd day of therapy. As methods of dynamic observation, photoregistration of the anterior segment with fluorescein staining and optical coherence tomography of the anterior segment were used. A clinical experiment has demonstrated the highest efficiency of the InP/ZnSe/ZnS 650 + Tobramycin complex in relation to Pseudomonas aeruginosa strain resistant to Tobramycin monotherapy.

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Yan, Yu, Handong Gui i Hua Bai. "Complete ZVS Analysis in Dual Active Bridge". IEEE Transactions on Power Electronics 36, nr 2 (luty 2021): 1247–52. http://dx.doi.org/10.1109/tpel.2020.3011470.

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Yang, Ping, i Michael Bredol. "Surface Passivation and Photoluminescence of Mn-Doped ZnS Nanocrystals". Research Letters in Materials Science 2008 (2008): 1–5. http://dx.doi.org/10.1155/2008/506065.

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Enhanced photoluminescence (PL) is reported from Mn-doped ZnS nanocrystals (NCs) capped with ZnS (ZnS:Mn/ZnS core-shell NCs) and thioglycolic acid (TGA) (ZnS:Mn/ZnS core-shell NCs dispersed in an alkaline TGA solution). The NCs were prepared using a reverse micelle route. Comparing with initial ZnS:Mn core NCs, the ZnS:Mn/ZnS core-shell NCs exhibit much stronger orange PL (~580 nm). This is presumably the result of effective passivation of quenching ZnS:Mn NCs surface states by a pure ZnS shell. As for TGA-capped ZnS:Mn/ZnS core-shell NCs, the parallel decrease of a defect-related emission of ZnS is associated with the formation of a shell surface layer of TGA-Zn complexes. In summary, the combination of ZnS shells with TGA ligands was demonstrated to yield ZnS:Mn NCs with narrow size distribution and intense PL.

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Cardoso Castaldo, Fernando, Denizar Cruz Martins i Ivo Barbi. "Aplicação da célula de comutação ZVS-PWM no conversor CC-CC ponte completa". Eletrônica de Potência 3, nr 1 (1.11.1998): 1–8. http://dx.doi.org/10.18618/rep.1998.1.001008.

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Mannam, Rayudu, Srinivasa Rao Gorantla i Nagesh Vangala. "A 500 Watts Single Stage Single Switch Soft Switched CCM PFC Flyback Converter with BCM Control". International Journal of Engineering & Technology 7, nr 4.24 (27.11.2018): 124. http://dx.doi.org/10.14419/ijet.v7i4.24.21871.

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Single stage isolated AC to DC converters find prominence due to simplicity and efficiency in addition to economics. Boundary control Mode BCM Flyback converters are widely used for such applications up to power levels of 200 watts. For higher power levels, average current control mode PFCs are used and two stage conversion is incorporated. In this paper, a novel technique for building a single stage PFC with a Continuous Conduction Mode CCM Flyback AC DC converter is proposed for 500 watts power. A practicalsingle stage converter is built with power factor correction and input output isolation. The unique feature of the new configuration lies in having only one primary MOSFET switch and adapting BCM control in a CCM Flyback configuration and achieving ZVS and ZCS while in CCM operation. Proposed configuration is best suited for battery charger applications. Also, the absence of high voltage bulk capacitor at the mains input adds lot of advantages in terms of eliminating inrush current and saving PCB area. A working model of 130 V Dc output and 4.0A is built and the test data are presented depicting the complete soft switching of all power devices and exhibiting the efficiencies in excess of 95%.

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Clayton, Jessica A., Katharina Keller, Mian Qi, Julia Wegner, Vanessa Koch, Henrik Hintz, Adelheid Godt i in. "Quantitative analysis of zero-field splitting parameter distributions in Gd(iii) complexes". Physical Chemistry Chemical Physics 20, nr 15 (2018): 10470–92. http://dx.doi.org/10.1039/c7cp08507a.

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Martynenko, Irina V., Anna O. Orlova, Vladimir G. Maslov, Anatoly V. Fedorov, Kevin Berwick i Alexander V. Baranov. "The influence of phthalocyanine aggregation in complexes with CdSe/ZnS quantum dots on the photophysical properties of the complexes". Beilstein Journal of Nanotechnology 7 (13.07.2016): 1018–27. http://dx.doi.org/10.3762/bjnano.7.94.

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The formation of nonluminescent aggregates of aluminium sulfonated phthalocyanine in complexes with CdSe/ZnS quantum dots causes a decrease of the intracomplex energy transfer efficiency with increasing phthalocyanine concentration. This was confirmed by steady-state absorption and photoluminescent spectroscopy. A corresponding physical model was developed that describes well the experimental data. The results can be used at designing of QD/molecule systems with the desired spatial arrangement for photodynamic therapy.

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Du, Zhifeng, Raphael E. F. de Paiva, Yun Qu i Nicholas Farrell. "Tuning the reactivity of Sp1 zinc fingers with platinum complexes". Dalton Transactions 45, nr 21 (2016): 8712–16. http://dx.doi.org/10.1039/c6dt01128d.

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The microenvironment around a zinc finger coordination unit affects the reactivity of apparently similar ZFs with Lewis acid platinum electrophiles. The unique dicysteine-bridged dinuclear platinum unit is the product of the reaction of [PtCl₂(en)] and the F3 of the transcription factor Sp1.

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Fortmann, Christian. "Bewegungsresistente Verben". Zeitschrift für Sprachwissenschaft 26, nr 1 (19.01.2007): 1–40. http://dx.doi.org/10.1515/zfs.2007.009.

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AbstractIn German, three types of morphologically complex verbs have to be distinguished with respect to V2-movement. Complex verbs either move as a whole or leave behind a particle or do not move at all. I argue that the latter type –

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Geddam, Kiran Kumar, i Elangovan Devaraj. "Real Time Hardware-in-Loop Implementation of LLC Resonant Converter at Worst Operating Point Based on Time Domain Analysis". Energies 15, nr 10 (16.05.2022): 3634. http://dx.doi.org/10.3390/en15103634.

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The inductor inductor capacitor (LLC) resonant topology has become more popular for deployment in high power density and high-efficiency power converter applications due to its ability to maintain zero voltage switching (ZVS) over a wider input voltage range. Due to their ease of operation and acceptable accuracy, frequency domain-related analytical methods using fundamental harmonic approximation (FHA) have been frequently utilized for resonant converters. However, when the switching frequency is far from the resonant frequency, the circuit currents contain a large number of harmonics, which cannot be ignored. Therefore, the FHA is incapable of guiding the design when the LLC converter is used to operate in a wide input voltage range applications due to its inaccuracy. As a result, a precise LLC converter model is needed. Time domain analysis is a precise analytical approach for obtaining converter attributes, which supports in the optimal sizing of LLC converters. This work strives to give a precise and an approximation-free time domain analysis for the exact modeling of high-frequency resonant converters. A complete mathematical analysis for an LLC resonant converter operating in discontinuous conduction mode (DCM)—i.e., the boost mode of operation below resonance—is presented in this paper. The proposed technique can confirm that the converter operates in PO mode throughout its working range; in addition, for primary MOSFET switches, it guarantees the ZVS and zero current switching (ZCS) for the secondary rectifier. As a function of frequency, load, and other circuit parameters, closed-form solutions are developed for the converter’s tank root mean square (RMS) current, peak stress, tank capacitor voltage, voltage gain, and zero voltage switching angle. Finally, an 8 KW LLC resonant converter is built in the hardware-in-loop (HIL) testing method on RT-LAB OP-5700 to endorse the theoretical study.

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Koo, Eunhae, i Jong-Chul Lee. "A Turn-On Fluorescent Probe for Detecting Nitric Oxide in Aqueous Media". Journal of Nanomaterials 2014 (2014): 1–5. http://dx.doi.org/10.1155/2014/276057.

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Imaging of nitric oxide (NO) in living cells can provide new insights in understanding unsolved pathways in the cardiovascular and neurological dysfunction and many types of cancers. For the detection of NO under physiological conditions, we synthesized a turn-on fluorescent probe comprising CdSe/ZnS quantum dots (QDs) coordinated with dirhodium complex. Emission from CdSe/ZnS-QDs is quenched when coordinated with the dirhodium complex but can be restored upon the displacement by nitric oxide.

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Liu, Jia-Jia, Yin-Shan Meng, Ivo Hlavička, Milan Orlita, Shang-Da Jiang, Bing-Wu Wang i Song Gao. "Determination of zero-field splitting in Co2+ halide complexes with magnetic and far-IR measurements". Dalton Transactions 46, nr 23 (2017): 7408–11. http://dx.doi.org/10.1039/c7dt01486d.

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Sarkar, Arup, Gunasekaran Velmurugan, Thayalan Rajeshkumar i Gopalan Rajaraman. "Deciphering the origin of invariance in magnetic anisotropy in {FeIIS4} complexes: a theoretical perspective". Dalton Transactions 47, nr 30 (2018): 9980–84. http://dx.doi.org/10.1039/c8dt02145g.

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Ramachandra, Srinidhi, Cristian Alejandro Strassert, David N. Reinhoudt, Daniel Vanmaekelbergh i Luisa De Cola. "Bidirectional Photoinduced Energy Transfer in Nanoassemblies of Quantum Dots and Luminescent Metal Complexes". Zeitschrift für Naturforschung B 69, nr 2 (1.02.2014): 263–74. http://dx.doi.org/10.5560/znb.2014-3323.

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This work describes the synthesis and photophysical characterization of Ir(III) and Ru(II) complexes bearing terminal amino groups, which act as anchoring units for the attachment to quantum dots, QDs. The photophysical properties of the metal complexes in combination with different types of QDs, allows directional photoinduced processes in the assemblies. In particular, we show photoinduced energy transfer from the luminescent excited Ir(III) unit to the CdTe nanocrystals, with an efficiency of 40%. The directionality was then inverted by employing an emitting Ru(II) complex as energy acceptor, in combination with photoluminescent CdSe/ZnS quantum dots. The efficiency of the photoinduced energy transfer from the nanocrystals to the Ru(II) center was estimated to be as high as 75%. This work provides model systems for nanoassemblies based on quantum dots and metal complexes for optoelectronic applications, and as active light-harvesting systems.

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Kulakovich, O. S., L. I. Gurinovich, L. I. Trotsiuk, A. A. Ramanenka, Hongbo Li, N. A. Matveevskaya i S. V. Gaponenko. "Manipulation of the quantum dots photostability using gold nanoparticles". Doklady of the National Academy of Sciences of Belarus 66, nr 2 (6.05.2022): 148–55. http://dx.doi.org/10.29235/1561-8323-2022-66-2-148-155.

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The effect of plasmonic films containing gold nanoparticles of different shape (nanospheres and nanorods) on the photostability of InP/ZnSe/ZnSeS/ZnS and CdSe/ZnCdS/ZnS quantum dots with core/shell structure has been determined. Gold nanospheres increase the photostability of InP/ZnSe/ZnSeS/ZnS quantum dots when excited by blue LED radiation when reducing the average lifetime of the excited state of quantum dots and, accordingly, when reducing the probability of Auger processes. An increase in the average lifetime of the excited state of CdSe/ZnCdS/ZnS quantum dots in complexes with gold nanorods leads to a decrease in the photostability upon excitation at 449 and 532 nm.

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Loseva, O. V., T. A. Rodina, A. V. Gerasimenko i A. V. Ivanov. "Species of Gold(III) Binding by Binuclear Zinc Dipropyldithiocarbamate: Supramolecular Self-Organization and Thermal Behavior of Ionic Complexes [Au(S2CNPr2)2]2[ZnCl4] and [Au(S2CNPr2)2]2[AuCl4][AuCl2]". Координационная химия 49, nr 1 (1.01.2023): 13–26. http://dx.doi.org/10.31857/s0132344x22700128.

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The reaction of binuclear zinc dipropyldithiocarbamate [Zn2{S2CN(C3H7)2}4] with an AuCl3/2 М HCl solution is studied. The double ionic complex [Au{S2CN(C3H7)2}2]2[ZnCl4] (I) is identified as the main species of gold(III) binding in the heterogeneous system under study and is characterized by 13С and 15N CP-MAS NMR spectroscopy. Single crystals of heterovalent compound [Au{S2CN(C3H7)2}2]2[AuCl4][AuCl2] (II) are sampled as a by-product. The crystal and supramolecular structures of complexes I and II are determined by the direct XRD method (CIF files CCDC nos. 2159171 and 2159170, respectively). The self-organization of the complex pseudopolymeric structures of compounds I and II are shown to be due to the binding of ionic structural units by secondary nonvalent interactions Au⋅⋅⋅S and S⋅⋅⋅Cl and hydrogen bonds C–H⋅⋅⋅Cl. The thermal behavior of the complexes is studied by simultaneous thermal analysis (STA), and the quantitative regeneration of bound gold (I and II) with the partial transformation of released ZnCl2 to ZnS (I) is found.

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Udoeva, Lyudmila Yu, Sergey N. Agafonov i Sofia A. Petrova. "Thermodynamic and experimental simulation of interactions in the Ta-ZnS system". Butlerov Communications 63, nr 9 (30.09.2020): 94–98. http://dx.doi.org/10.37952/roi-jbc-01/20-63-9-94.

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The article presents the results of studies to estimation the possibility of sulfiding of metallic tantalum by zinc sulfide in an inert atmosphere. To theoretically substantiate the possibility of the process, the HSC 6.12 Chemistry software package (Outotec) was used, which allows predicting the equilibrium composition of the interaction products. The Gibbs energies of possible reactions in the ZnS-Ta system are calculated, the optimum operating parameters of the process of complete transformation of metallic tantalum into TaS2 are determined. Experimental studies were carried out in a tubular furnace in a flow of an inert gas (helium) supplied through a closed loop of an alundum reactor. Components with different molar ratios compressed into tablets were kept at the temperature 1300 ° C for 90 minutes. It has been found tantalum disulfide of two modifications (hexagonal and trigonal systems) and Ta5S8 (14.1%) are formed at a stoichiometric ZnS / Ta molar ratio of 2.0. Its subsulfides (Ta1.23S2, Ta3.1S6, TaS (y)), which are intermediate phases in the transformation of tantalum-to-TaS2, are formed if a sulfidizer is deficient. The identification of the phases and the estimation of their proportion in the sulfiding product were made by the full-profile analysis by Rietveld method. The experimental conditions did not reveal the formation of complex sulfides like the ZnxTaS2, the formation of which is possible because of zinc intercalation between the layers of the tantalum disulfide basic structure of the crystal lattice.

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Maskaeva, Larisa N., Anastasia D. Kutyavina, Anna I. Zhdanova, Roman A. Gagarin, Tatiana V. Vinogradova i Vyacheslav F. Markov. "Chemical bath synthesis of metal chalcogenide films. Part 39. Chemical bath deposition of ZnS films by thioacetamide". Butlerov Communications 57, nr 1 (31.01.2019): 115–26. http://dx.doi.org/10.37952/roi-jbc-01/19-57-1-115.

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ZnS thin films are promising as a buffer layer in solar cells, which can be basis of photovoltaic cells, photoelectric sensors, and light-emitting diodes. For the preparation of thin ZnS films by chemical bath deposition, thioacetamide or thiourea is used as a chalcogenization agent, and ammonia, triethanolamine and sodium citrate are mainly used as ligands, carrying out the process in an alkaline medium. In the present work, in order to predict the conditions of hydrochemical deposition of ZnS films, we have analyzed ionic equilibria in two reaction systems “ZnCl2 – NH4OH – CH3CNH2” and “ZnCl2 – CH3CSNH2 – KHC8H4O4” that differ in acidity of the medium. An analysis of ionic equilibrium showed that in the first bath ~80% of the metal is in the form of a neutral hydroxo complex Zn(OH)2 at pH > 7, and in the second more than 98% of zinc is present as acetate complexes Zn(CH3COO)+ and Zn(CH3COO)2 in the range of pH from 0 to 7. The thermodynamic evaluation of the boundary conditions for the formation of zinc sulfide made it possible to conclude that a zinc sulfide film can be formed in both systems without the admixture of Zn(OH)2 hydroxide. ZnS films were obtained by hydrochemical deposition with thick about 100 nm from both systems. Using local energy-dispersive elemental analysis, it was found that the average ratio between the main elements of Zn and S in the layers obtained in an alkaline medium is 49.48 and 50.52 at.%, and in the synthesized from acidic solutions – 50.35 and 49.65 at.%. According to the data of electron microscopy, up to 85% of the agglomerates have an average size of 200-450 nm that formed from ZnS particles growing in an alkaline reaction bath. At the same time, there are aggregates whose dimensions reach 700 nm. The layers that deposited from relatively acidic solutions are distinguished by a higher degree of dispersion. Here up to ~90% of the film-forming particles is in the nanoscale range from 50 to 90 nm.

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Kurshanov, D. A., I. A. Arefina, M. S. Stepanova, A. Dubavik i A. V. Baranov. "Effect of Fe-=SUB=-3-=/SUB=-O-=SUB=-4-=/SUB=- nanoparticle concentration on the luminescence of AgInS-=SUB=-2-=/SUB=-/ZnS in hybrid complex CaCO-=SUB=-3-=/SUB=--Fe-=SUB=-3-=/SUB=-O-=SUB=-4-=/SUB=-@AgInS-=SUB=-2-=/SUB=-/ZnS-=SUP=-*-=/SUP=-". Оптика и спектроскопия 129, nr 11 (2021): 1424. http://dx.doi.org/10.21883/os.2021.11.51649.1418-21.

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In this paper, we studied the properties of a multifunctional system, in which the luminescent and magnetic properties are combined. The calcium carbonate microspheres are used as porous matrices for complexes combining luminescence properties of AgInS2/ZnS quantum dots and magnetic properties of Fe3O4 nanoparticles. The study investigates the effect of magnetic nanoparticles concentration on optical properties of quantum dots in CaCO3-Fe3O4@AgInS2/ZnS complexes. It is shown that applying calcium carbonate microspheres as a matrix permits to reduce quenching of the quantum dots luminescence. Keywords: hybrid system; ternary quantum dots; magnetic nanoparticles; iron oxide; calcium carbonate microspheres.

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Kurshanov D.A., Arefina I. A., Stepanova M. S., Dubavik A. i Baranov A. V. "Effect of Fe-=SUB=-3-=/SUB=-O-=SUB=-4-=/SUB=- nanoparticle concentration on the luminescence of AgInS-=SUB=-2-=/SUB=-/ZnS in hybrid complex CaCO-=SUB=-3-=/SUB=--Fe-=SUB=-3-=/SUB=-O-=SUB=-4-=/SUB=-@AgInS-=SUB=-2-=/SUB=-/ZnS". Optics and Spectroscopy 130, nr 14 (2022): 2134. http://dx.doi.org/10.21883/eos.2022.14.53999.1418-21.

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In this paper, we studied the properties of a multifunctional system, in which the luminescent and magnetic properties are combined. The calcium carbonate microspheres are used as porous matrices for complexes combining luminescence properties of AgInS2/ZnS quantum dots and magnetic properties of Fe3O4 nanoparticles. The study investigates the effect of magnetic nanoparticles concentration on optical properties of quantum dots in CaCO3-Fe3O4@AgInS2/ZnS complexes. It is shown that applying calcium carbonate microspheres as a matrix permits to reduce quenching of the quantum dots luminescence. Keywords: hybrid system; ternary quantum dots, magnetic nanoparticles, iron oxide; calcium carbonate microspheres.

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Liang, Caishuang, Xiaoqing Liu, Chunyan Chen, Xiaoming Chen i Changqun Cai. "Vitro toxicity assessments of nano-ZnS on bovine serum albumin by multispectroscopic methods". Canadian Journal of Chemistry 94, nr 10 (październik 2016): 877–81. http://dx.doi.org/10.1139/cjc-2016-0060.

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Measuring protein damaged by nanomaterials may give insight into the mechanisms of toxicity of nanomaterials. The toxic effects of nano-ZnS, nano-Al2O3, nano-ZnCO3, and nano-SiO2 on bovine serum albumin (BSA) were thoroughly studied by multispectroscopic methods, including resonance light scattering, UV-vis absorption spectroscopy, fluorescence spectroscopy, circular dichroism, etc., and the most obvious changes were observed when nano-ZnS interacted with BSA among the four nanoparticles. The experimental results showed that nano-ZnS can bind with BSA to form a complex when the conjugating ratio is 1:1. nano-ZnS can alter the structure of BSA, leading to a loosening of the protein skeleton, and therefore, the internal hydrophobic amino acids are exposed in the loose structure, which indicated that nano-ZnS has an obvious toxic effect on BSA. This work provides a new perspective and method for determining the toxic effects of nanomaterials on biological macromolecules.

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Ehm, Christian, Antonio Vittoria, Georgy P. Goryunov, Vyatcheslav V. Izmer, Dmitry S. Kononovich, Oleg V. Samsonov, Rocco Di Girolamo i in. "An Integrated High Throughput Experimentation/Predictive QSAR Modeling Approach to ansa-Zirconocene Catalysts for Isotactic Polypropylene". Polymers 12, nr 5 (27.04.2020): 1005. http://dx.doi.org/10.3390/polym12051005.

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Compared to heterogenous Ziegler–Natta systems (ZNS), ansa-metallocene catalysts for the industrial production of isotactic polypropylene feature a higher cost-to-performance balance. In particular, the C2-symmetric bis(indenyl) ansa-zirconocenes disclosed in the 1990s are complex to prepare, less stereo- and/or regioselective than ZNS, and lose performance at practical application temperatures. The golden era of these complexes, though, was before High Throughput Experimentation (HTE) could contribute significantly to their evolution. Herein, we illustrate a Quantitative Structure – Activity Relationship (QSAR) model trained on a robust and highly accurate HTE database. The clear-box QSAR model utilizes, in particular, a limited number of chemically intuitive 3D geometric descriptors that screen various regions of space in and around the catalytic pocket in a modular way thus enabling to quantify individual substituent contributions. The main focus of the paper is on the methodology, which should be of rather broad applicability in molecular organometallic catalysis. Then again, it is worth emphasizing that the specific application reported here led us to identify in a comparatively short time novel zirconocene catalysts rivaling or even outperforming all previous homologues which strongly indicates that the metallocene story is not over yet.

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Cárcamo, Alberto, Alejandro Fernandez-Hernandez, Fernando Gonzalez-Hernando, Aitor Vázquez i Alberto Rodríguez. "Variable Switching Frequency for ZVS over Wide Voltage Range in Dual Active Bridge". Electronics 13, nr 10 (7.05.2024): 1800. http://dx.doi.org/10.3390/electronics13101800.

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The Dual Active Bridge (DAB) converter is known for its advantageous characteristics, including bidirectionality, galvanic isolation, and soft-switching operation. However, achieving Zero Voltage Switching (ZVS) across the complete operation range is not guaranteed, particularly through a wide input–output voltage ratio. This paper explores the integration of the switching frequency as a control variable in the DAB converter to ensure ZVS operation across a wide voltage range, employing Single Phase Shift (SPS) modulation. The study evaluated the RMS and reactive currents under variable switching frequency, presenting the advantages of this approach. Moreover, it includes a design-oriented analysis of the ZVS limits and their relationship with the switching frequency, aiming to ensure ZVS at any operating point. Experimental results validated the theoretical analysis, while presenting the main advantages of variable switching frequency implementation.

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Jablanovic, Anastasija D., Marianna Z. Bekanova, Ekaterina A. Litmanovich, Oleg N. Karpov, Miron A. Bugakov, George A. Shandryuk, Alexander A. Ezhov, Raisa V. Talroze i Elena V. Chernikova. "Monochelic Versus Telechelic Poly(Methyl Methacrylate) as a Matrix for Photoluminescent Nanocomposites with Quantum Dots". Molecules 26, nr 14 (7.07.2021): 4131. http://dx.doi.org/10.3390/molecules26144131.

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Nanocomposites based on CdSe or CdSe/ZnS quantum dots (QDs) and poly(methyl methacrylate) (PMMA) of different molecular weights and functionality were synthesized by ligand exchange of oleic acid with RAFT-based PMMA. The successful ligand exchange was confirmed by dynamic light scattering in combination with the approach “macromolecules—ghosts” and transmission electron microscopy. Comparative study of mono- and telechelics of PMMA revealed the similarities and differences in their behavior in formation of complexes with QDs and the optical properties of the corresponding nanocomposites. Telechelics exhibited higher efficiency in the complex formation and seemed to be promising candidates for the construction of devices based on QDs and polymer matrix for optical applications.

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Phoohinkong, Weerachon, Thitinat Sukonket i Udomsak Kitthawee. "A Facile Fynthesis of ZnS Nanostructures via Liquid-Solid Reactions". Advanced Materials Research 979 (czerwiec 2014): 184–87. http://dx.doi.org/10.4028/www.scientific.net/amr.979.184.

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Zinc sulfide (ZnS) nanostructures are important materials for many technologies such as sensors, infrared windows, transistors, LED displays, and solar cells. However, many methods of synthesizing ZnS nanostructures are complex and require expensive equipment. In this study, a liquid-solid chemical reaction without surfactant was used to synthesize ZnS at room temperature. In addition, commercial grade zinc oxide (ZnO) particles were used as a precursor. The effect of the addition of acids and inorganic salts were investigated. The products were characterized by field emission scanning electron microscopy (FESEM) coupled with energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM). The results show that the nanoparticles of ZnS were obtained in hydrochloric acid and acetic acid addition. The diameters were in the range of 10 to 20 nm and 50 to 100 nm, respectively. In the case of a sodium chloride salt addition, a ZnS structure was obtained with a particle size of approximately 5 nm and a flake-like morphology.

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Sheng, Wei Chen, Jing Tan, Ping Wu, Qiao Chen i Zhi Ping Zhou. "Synthesis and Optical Properties of ZnS Nanoparticles Using Multi-Mercaptan-Terminated Thio Ether as Surface Modifier". Key Engineering Materials 575-576 (wrzesień 2013): 24–29. http://dx.doi.org/10.4028/www.scientific.net/kem.575-576.24.

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ZnS nanoparticles have been prepared by using 2, 3-dimercaptoethylthiopropanethiol (BES) as the coordinating modifier reagent to form Zn-thiol complex at low reaction temperatures. By controlling the experimental conditions, the diameter of the ZnS nanopaticles can be tuned from 43 nm to 115 nm. Systematic experiments were carried out to investigate the factors such as the amounts of the reagents (thiourea and BES) and the temperature, which have great influence on the sizes of the products. And when the content of BES is much higher, ZnS nanopaticles with mercapto surface modification were synthesized. In addition, massive blue shift in UV-vis spectra has been observed and the photoluminescence spectra of the ZnS show a strong emission at approximate 432 nm and 527 nm. Therefore, the preparation and properties studies of different ZnS sizes will offer great opportunities to explore the dependence of a material’s properties and find many interesting applications in the optical devices.

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Isaeva, Anastasya A., i Vladimir P. Smagin. "INFLUENCE OF LEAD IONS ON PHOTOLUMINESCENT PROPERTIES OF POLYMETHYL METACRYLATE /(Zn,Pb)S/CdS/(Zn,Pb)S COMPOSITIONS". IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 63, nr 11 (27.10.2020): 82–87. http://dx.doi.org/10.6060/ivkkt.20206311.6231.

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The paper presents the results of a study of the effect of lead ions on the photoluminescent properties of core / shell / shell nanostructures based on zinc and cadmium sulfides synthesized in situ during the formation of polyacrylate composition. ZnS/CdS/ZnS and (Zn,Pb)S/CdS/(Zn,Pb)S nanoparticles were obtained by colloidal synthesis in a medium of (poly) methyl methacrylate. Colloidal solutions are solidified to a glassy state by radical thermal polymerization of methyl methacrylate in a block. To initiate the polymerization, benzoyl peroxide was introduced into the solutions in an amount of 0.1% by weight of methyl methacrylate. The conclusion on the formation of nanosized particles of complex composition in the polymer matrix is made by comparing the luminescence and luminescence spectra of the compositions containing ZnS and CdS particles and their structure. In the photoluminescence spectra of the (poly) methyl methacrylate/(ZnS/CdS/ZnS) composition, two complex bands associated with crystal lattice defects of ZnS particles (380 - 530 nm) and CdS (530 - 840 nm) were detected. The excitation of photoluminescence occurs as a result of interband transitions of electrons in each of the semiconductor layers, as well as during transitions of electrons from the conduction band to defect levels located in the forbidden band of the semiconductor structure. In the luminescence excitation spectrum, they correspond to bands of various intensities in the range of 300–420 nm and 300–480 nm. From the overlap of the ZnS luminescence bands and the excitation of CdS luminescence, it was concluded that the radiation of the core is absorbed by the CdS coating layer and that energy is transferred from the levels of structural defects of ZnS to the levels of structural defects of CdS at the layer boundary. Doping of zinc sulfide layers with lead ions leads to a change in the luminescence spectrum in the region of 380 - 530 nm and the disappearance of the CdS luminescence band in the range of 530 - 840 nm. The observed changes are associated with defects that create Pb2+ ions in the crystal lattice of the ZnS outer shell and the screening of the (Zn,Pb)S shell of the inner layers from the penetration of exciting radiation.

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Ajibade, Peter A., i Jejenija Osuntokun. "Synthesis and Characterization of Hexadecylamine Capped ZnS, CdS, and HgS Nanoparticles Using Heteroleptic Single Molecular Precursors". Journal of Nanomaterials 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/782526.

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Zn(II), Cd(II), and Hg(II) complexes of tetramethyl thiuram disulfides and 1-ethoxylcarbonyl-1-ethylenecarbonyl-2-dithiolate were synthesized and characterized by elemental analysis, FTIR, and1H- and13C-NMR spectroscopy. The complexes were thermolysed in hexadecylamine as single molecule precursors to prepare HDA capped ZnS, CdS, and HgS nanoparticles. The optical and structural properties of the nanoparticles are reported. ZnS nanoparticles existed in the hexagonal phase with particle sizes of 8–15 nm; the CdS nanoparticles in the cubic phase have particle sizes in the range 4–7 nm and the HgS nanoparticles indexed to face-centered cubic phase have an average particle size of 7–12 nm.

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Mersel, Maali-Amel, Lajos Fodor, Péter Pekker, Miklós Jakab, Éva Makó i Ottó Horváth. "Effects of Preparation Conditions on the Efficiency of Visible-Light-Driven Hydrogen Generation Based on Cd0.25Zn0.75S Photocatalysts". Catalysts 11, nr 12 (16.12.2021): 1534. http://dx.doi.org/10.3390/catal11121534.

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Photocatalytic H2 production utilizing H2S, an industrial side-product, is regarded as an environmentally friendly process to produce clean energy through direct solar energy conversion. For this purpose, sulfide-based materials, such as photocatalysts, have been widely used due to their good solar response and high photocatalytic activity. In this work, a ZnS–CdS composite was studied, and special attention was dedicated to the influence of the preparation parameters on its H2 production activity. The ZnS–CdS composite, with an enhanced photoactivity for H2 production, was synthesized both from ammine complexes and, in a conventional way, directly from acetates at various pH values. Deviating from the traditional method, the photoactivity of ZnS–CdS prepared from ammine complexes was not affected by the pH. Besides, the hydrothermal treatment and the ammonia content strongly influenced the rate of H2 production in this system. DRS, TEM, SEM, XRD, and quantum yield measurements prove the dependence of the photoactivity of these catalysts on the structural and morphological properties determined by the preparation conditions. The promising photocatalytic efficiency achieved with the application of these ZnS–CdS catalysts, prepared without any metal deposition, encourages further investigations to enhance the rate of hydrogen generation by optimization of the reaction conditions for practical utilization.

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Zou, Xiaochuan, Yue Wang, Cun Wang, Kaiyun Shi, Yanrong Ren i Xin Zhao. "Chiral MnIII (Salen) Immobilized on Organic Polymer/Inorganic Zirconium Hydrogen Phosphate Functionalized with 3-Aminopropyltrimethoxysilane as an Efficient and Recyclable Catalyst for Enantioselective Epoxidation of Styrene". Polymers 11, nr 2 (26.01.2019): 212. http://dx.doi.org/10.3390/polym11020212.

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Organic polymers/inorganic zirconium hydrogen phosphate (ZSPP, ZPS-IPPA, and ZPS-PVPA) functionalized with 3-aminopropyltrimethoxysilane were prepared and used to support chiral MnIII (salen) complexes (Jacobsen’s catalyst). Different characterization methods demonstrated that the chiral MnIII (salen) complexes was successfully supported on the surface of the carrier (ZSPP, ZPS-IPPA, or ZPS-PVPA) through a 3-aminopropyltrimethoxysilane group spacer. The supported catalysts effectively catalyzed epoxidation of styrene with m-chloroperbenzoic acid (m-CPBA) as an oxidant in the presence of N-methylmorpholine N-oxide (NMO) as an axial base. These results (ee%, 53.3–63.9) were significantly better than those achieved under a homogeneous counterpart (ee%, 46.2). Moreover, it is obvious that there was no significant decrease in catalytic activity after the catalyst 3 was recycled four times (cons%: from 95.0 to 92.6; ee%: from 64.7 to 60.1). Further recycles of catalyst 3 resulted in poor conversions, although the enantioselectivity obtained was still higher than that of corresponding homogeneous catalyst even after eight times. After the end of the eighth reaction, the solid catalyst was allowed to stand in 2 mol/L of dilute hydrochloric acid overnight, prompting an unexpected discovery that the catalytic activity of the catalyst was recovered again at the 9th and 10th cycles of the catalyst.

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Sliusariak, T. K., Y. M. Andriichuk, S. A. Vojtovych, M. A. Zhukovskyi i Y. B. Khalavka. "Synthesis of CdSe/ZnS Nanoparticles with Multiple Photoluminescence". Фізика і хімія твердого тіла 21, nr 1 (29.03.2020): 105–12. http://dx.doi.org/10.15330/pcss.21.1.105-112.

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The CdSе/ZnS nanostructures of Core-Shell type, that have multi-wave emission, are described and a scheme of possible energy transitions in the studied system is presented. CdSe nuclei were synthesized by mixing cadmium and selenium precursors without creating an inert atmosphere. The cadmium complex with sulphanilamide was used as a cadmium precursor and simultaneously as a stabilizing ligand. To grow the shell, zinc stearate and thiourea were gradually added to the solution of cadmium selenide nuclei in octadecene at 200°C. TEM studies show that the obtained CdSe/ZnS nanoparticles have the shape close to tetrahedral with an effective diameter up to 10 nm. The thickness of the ZnS shell is about 3-4 nm. From the absorption spectra of the CdSe/ZnS nanoparticles, it is clear that the shell growth leads to a sharp increase in the absorption in the short wavelentgh area, which means the formation of a wide gap ZnS material. The obtained CdSe/ZnS nanostructures emit three fluorescence peaks in the visible range. They are attributed to exciton transitions in the nucleus, recombination at defects of the boundary between the core and the shell, and recombination at defects of the shell. Such property provides CdSe/ZnS nanocrystals with a wide range of functionalities.

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Zhang, Qianting, Shu-Yan Ji, Kiran Busayavalasa i Chao Yu. "SPO16 binds SHOC1 to promote homologous recombination and crossing-over in meiotic prophase I". Science Advances 5, nr 1 (styczeń 2019): eaau9780. http://dx.doi.org/10.1126/sciadv.aau9780.

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Segregation of homologous chromosomes in meiosis I is tightly regulated by their physical links, or crossovers (COs), generated from DNA double-strand breaks (DSBs) through meiotic homologous recombination. In budding yeast, three ZMM (Zip1/2/3/4, Mer3, Msh4/5) proteins, Zip2, Zip4, and Spo16, form a “ZZS” complex, functioning to promote meiotic recombination via a DSB repair pathway. Here, we identified the mammalian ortholog of Spo16, termed SPO16, which interacts with the mammalian ortholog of Zip2 (SHOC1/MZIP2), and whose functions are evolutionarily conserved to promote the formation of COs. SPO16 localizes to the recombination nodules, as SHOC1 and TEX11 do. SPO16 is required for stabilization of SHOC1 and proper localization of other ZMM proteins. The DSBs formed in SPO16-deleted meiocytes were repaired without COs formation, although synapsis is less affected. Therefore, formation of SPO16-SHOC1 complex–associated recombination intermediates is a key step facilitating meiotic recombination that produces COs from yeast to mammals.

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Graber, Joseph R., Jared R. Leadbetter i John A. Breznak. "Description of Treponema azotonutricium sp. nov. and Treponema primitia sp. nov., the First Spirochetes Isolated from Termite Guts". Applied and Environmental Microbiology 70, nr 3 (marzec 2004): 1315–20. http://dx.doi.org/10.1128/aem.70.3.1315-1320.2004.

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ABSTRACT Long after their original discovery, termite gut spirochetes were recently isolated in pure culture for the first time. They revealed metabolic capabilities hitherto unknown in the Spirochaetes division of the Bacteria, i.e., H2 plus CO2 acetogenesis (J. R. Leadbetter, T. M. Schmidt, J. R. Graber, and J. A. Breznak, Science 283:686-689, 1999) and dinitrogen fixation (T. G. Lilburn, K. S. Kim, N. E. Ostrom, K. R. Byzek, J. R. Leadbetter, and J. A. Breznak, Science 292:2495-2498, 2001). However, application of specific epithets to the strains isolated (Treponema strains ZAS-1, ZAS-2, and ZAS-9) was postponed pending a more complete characterization of their phenotypic properties. Here we describe the major properties of strain ZAS-9, which is readily distinguished from strains ZAS-1 and ZAS-2 by its shorter mean cell wavelength or body pitch (1.1 versus 2.3 μm), by its nonhomoacetogenic fermentation of carbohydrates to acetate, ethanol, H2, and CO2, and by 7 to 8% dissimilarity between its 16S rRNA sequence and those of ZAS-1 and ZAS-2. Strain ZAS-9 is proposed as the type strain of the new species, Treponema azotonutricium. Strains ZAS-1 and ZAS-2, which are H2-consuming, CO2-reducing homoacetogens, are proposed here to be two strains of the new species Treponema primitia. Apart from the salient differences mentioned above, the genomes of all three strains were similar in size (3,461 to 3,901 kb), in G+C content (50.0 to 51.0 mol%), and in possession of 2 copies of the gene encoding 16S rRNA (rrs). For comparison, the genome of the free-living spirochete Spirochaeta aurantia strain J1 was analyzed by the same methods and found to have a size of 3,719 kb, to contain 65.6 mol% G+C, and also to possess 2 copies of the rrs gene.

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