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Littérature scientifique sur le sujet « 2-Bimetallics »

Auteur : Grafiati
Publié le 11 janvier 2025

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Articles de revues sur le sujet "2-Bimetallics"

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Yang, Chunpeng, Byung Hee Ko, Sooyeon Hwang, Zhenyu Liu, Yonggang Yao, Wesley Luc, Mingjin Cui et al. « Overcoming immiscibility toward bimetallic catalyst library ». Science Advances 6, no 17 (avril 2020) : eaaz6844. http://dx.doi.org/10.1126/sciadv.aaz6844.

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Bimetallics are emerging as important materials that often exhibit distinct chemical properties from monometallics. However, there is limited access to homogeneously alloyed bimetallics because of the thermodynamic immiscibility of the constituent elements. Overcoming the inherent immiscibility in bimetallic systems would create a bimetallic library with unique properties. Here, we present a nonequilibrium synthesis strategy to address the immiscibility challenge in bimetallics. As a proof of concept, we synthesize a broad range of homogeneously alloyed Cu-based bimetallic nanoparticles regardless of the thermodynamic immiscibility. The nonequilibrated bimetallic nanoparticles are further investigated as electrocatalysts for carbon monoxide reduction at commercially relevant current densities (>100 mA cm−2), in which Cu0.9Ni0.1 shows the highest multicarbon product Faradaic efficiency of ~76% with a current density of ~93 mA cm−2. The ability to overcome thermodynamic immiscibility in multimetallic synthesis offers freedom to design and synthesize new functional nanomaterials with desired chemical compositions and catalytic properties.
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Smith, KA, GB Deacon, WR Jackson et JM Miller. « Preparation and Reactivity of Some Phenyl-bismuth(III) Quinolin-8-olate Derivatives ». Australian Journal of Chemistry 49, no 2 (1996) : 231. http://dx.doi.org/10.1071/ch9960231.

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The bimetallics [ PhBi (Ox)2( NaX )n] (Ox- = quinolin-8-olate: X = Cl , Br or I), containing variable amounts of sodium halides, have been prepared by reaction of PhBiX2 with Na(Ox) (mole ratio 1 : 2) or of Ph2BiX with Na(Ox) (mole ratio 1 : 1) in ethanol. A similar preparation has given [ PhBi ( MeOx )2( NaI )n] ( MeOx - = 2-methylquinolin-8-olate) . The bimetallics have been characterized by X-ray powder photography, f.a.b . mass spectrometry and 1H n.m.r. and electronic spectroscopy. Sodium halide-free PhBi (Ox)2 was obtained from the reaction of Ph2BiCl with Na(Ox) in the presence of 15-crown-5, or from treatment of PhBiI2 or Ph2BiI with NBu4(Ox). Reaction of equimolar amounts of PhBiI2 and Na(Ox) gives Bi(Ox)2I, which can also be obtained from BiI3 and Na(Ox) in a 1:1 or 1:2 stoichiometry. Treatment of PhBiI2 with M(0x) (M = Na or K) in a 1:3 mole ratio yields [ MPhBi (Ox)3] bimetallics, which appear to contain both chelating and unidentate Ox ligands from their electronic spectra.
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Verma, Alkadevi, Rajeev Kumar Gupta, Madhulata Shukla, Manisha Malviya et Indrajit Sinha. « Ag–Cu Bimetallic Nanoparticles as Efficient Oxygen Reduction Reaction Electrocatalysts in Alkaline Media ». Journal of Nanoscience and Nanotechnology 20, no 3 (1 mars 2020) : 1765–72. http://dx.doi.org/10.1166/jnn.2020.17154.

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The alkaline medium oxygen reduction reaction (ORR) activities of Ag–Cu bimetallic nanoparticles (BNPs), consisting of neighboring Ag and Cu domains, were studied and compared with those of pure Ag and Cu nanoparticles prepared by the same polyol route. Three variations of Ag–Cu BNPs viz. Ag–Cu (4:1), Ag–Cu (2:1), Ag–Cu (1:1) BNPs were considered. The electrocatalytic performances of these nanoparticles were investigated by using different techniques, such as cyclic voltammetry (CV) and linear sweep voltammograms (LSV). The Ag–Cu bimetallics demonstrated synergistic ORR electrocatalytic activity compared to pure Ag or Cu. Optimum values of these parameters were observed for Ag–Cu (4:1) BNPs. According to LSV, the reduction peak position is at lower applied potential and showed higher intensity for the Ag–Cu (4:1) as compared to Ag–Cu (2:1) and Ag–Cu (1:1) BNPs. Density Functional Theory (DFT) calculations show that charge transfer from Cu to Ag (in the bimetallic nanoparticles) results in their stronger oxygen interaction and water activation properties relative to that of pure Ag nanoparticles.
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Agrotis, Stefanos, Daren J. Caruana, Albertus Denny Handoko, Mustafa Emre Sener et Oliver S. J. Hagger. « Atmospheric Pressure Plasma Jet Synthesis and Characterization of Copper-Silver Bimetallic Materials as Electrocatalysts for CO2 Reduction ». ECS Meeting Abstracts MA2024-01, no 24 (9 août 2024) : 1403. http://dx.doi.org/10.1149/ma2024-01241403mtgabs.

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Copper-silver (Cu-Ag) bimetallics and alloys are attractive due to their enhanced performance compared to their parent metals in various fields including electronics, batteries, biomedicine, solar technology, energy storage, and catalysis.[1] Existing methods for synthesizing Cu-Ag bimetallics suffer from major drawbacks such as intense temperature and pressure conditions, pre and post-treatment processes, and multiple time-consuming steps.[2, 3] In this work, Cu-Ag bimetallic films were synthesized under various ratios for the first time using a newly developed Atmospheric Pressure Plasma Jet (APPJ) system. Synthesis was done in a single step, in under 15 minutes. The samples exhibited strong adhesion onto various substrates such as glass and glassy carbon. This direct-deposition technique requires low power input (<50 W) without the need for any pre- or post-treatment processes and with little to no waste. This contrasts with wet chemistry, where deposition normally takes 12-24 hours followed by thermal processes that produce several waste products.[4] Considering the high melting points (MP) of pure Cu and Ag (MP of Cu is ca. 1,085 °C and MP of Ag is ca. 962 °C), and the fact that they are immiscible, the formation of Cu-Ag alloys usually requires a high amount of energy under intense conditions.[5] These Cu-Ag films were characterized via cyclic voltammetry (CV), Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). Here, we demonstrate that by only mixing low-concentration metal salt solutions and using a neutral gas (helium), we can readily synthesize metal alloys while controlling their thickness, shape, composition, and metal ratios. From an electrochemical point of view, APPJ drives the reduction of metal cations from the presence of free electrons. This suggests the presence of a medium that is considered either as an electrode, due to the presence of electrons, or as an electrolyte, due to their electrical conduction.[6] These plasma-synthesized materials were tested as electrocatalysts for reducing atmospheric carbon dioxide (CO2) under various potentials. The performance of these catalysts was assessed via electrochemical surface area (ECSA), electrochemical impedance spectroscopy (EIS), and pulse voltammetry techniques. Copper is the only heterogeneous catalyst that converts CO2 into valuable chemicals, such as hydrocarbons, aldehydes, and alcohols.[7] Interestingly, we illustrate that the addition of silver improves the catalytic activity of copper toward CO2 reduction under low potentials. This is a desirable property given the anticipated transition to green energy. References Tantawy, H.R., et al., Novel synthesis of bimetallic Ag-Cu nanocatalysts for rapid oxidative and reductive degradation of anionic and cationic dyes. Applied Surface Science Advances, 2021. 3: p. 100056. Zhang, X., et al., Microstructures and properties of 40Cu/Ag (Invar) composites fabricated by powder metallurgy and subsequent thermo-mechanical treatment. Metallurgical and Materials Transactions A, 2018. 49: p. 1869-1878. Rajashekhar, B., et al., Electro co-deposition of copper-silver nanocrystallite alloy cluster: A way for tunable SERS substrate development. Materials Letters: X, 2022. 15: p. 100157. Jie, S., et al., Preparation of copper–silver alloy with different morphologies by a electrodeposition method in 1-butyl-3-methylimidazolium chloride ionic liquid. Bulletin of Materials Science, 2019. 42: p. 1-4. Banhart, J., et al., Electronic properties of single-phased metastable Ag-Cu alloys. Physical Review B, 1992. 46(16): p. 9968. Rumbach, P., et al., The solvation of electrons by an atmospheric-pressure plasma. Nature communications, 2015. 6(1): p. 7248. Kuhl, K.P., et al., New insights into the electrochemical reduction of carbon dioxide on metallic copper surfaces. Energy & Environmental Science, 2012. 5(5): p. 7050-7059.
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Lee, Shung-Ik, John M. Vohs et Raymond J. Gorte. « A Study of SOFC Anodes Based on Cu-Ni and Cu-Co Bimetallics in CeO[sub 2]-YSZ ». Journal of The Electrochemical Society 151, no 9 (2004) : A1319. http://dx.doi.org/10.1149/1.1774184.

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Deacon, GB, CM Forsyth, WC Patalinghug, AH White, A. Dietrich et H. Schumann. « Organolanthanoids. XVII. The Synthesis of Bis(diphenylphosphinocyclopentadienyl)ytterbium(II) and Derived Heterobimetallic Complexes [Yb(thf)n(C5H4PPh2)2Z] [Z=Ni(CO)2, Mo(CO)4 or PtMe2 ; n = 1 or 2 ; thf = Tetrahydrofuran]. The X-Ray Crystal-Structure of [Yb(thf)2(C5H4PPh2)2Ni(CO)2] ». Australian Journal of Chemistry 45, no 3 (1992) : 567. http://dx.doi.org/10.1071/ch9920567.

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Reaction of diphenylphosphinocyclopentadiene with Yb (C6F5)2 or with ytterbium metal and Hg(C6F5)2 in tetrahydrofuran ( thf ) gives, after workup with toluene, the phosphinoytter-bocene , [Yb (C5H4PPh2)2( thf )]. Treatment with thf or with N,N,N′,N′- tetramethylethane-1,2-diamine ( tmen ) yields [ Yb (C5H4PPh2)2L2] (L = thf or L2 = tmen ). Redox trans- metallation between ytterbium metal and Tl (C5H4PPh2) in l,2-dimethoxyethane ( dme ) gives thallium metal and [ Yb (C5H4PPh2)2(dme )]. The ytterbium-transition metal hetero-bimetallics [ Yb ( thf ) (C2H4PPh2)2Z]. nPhMe [Z = Ni(CO)2, Mo(CO)4 or PtMe2, n = 2/3 or 1] have been prepared by reaction of [ Yb ( thf )(C5H4PPh2)2] with Ni(CO)2(PPh3)2, Mo(CO)4( nbd ) ( nbd = norbornadiene ) or PtMe2(cod) (cod = cycloocta-1,5-diene) in toluene. Treatment of the heterobimetallics with tetrahydrofuran [Z = PtMe2 or Mo(CO)4] or a preparation in thf /toluene [Z = Ni(CO)2] yields [ Yb ( thf )2(C5H4PPh2)2PtMe2]. thf, [ Yb ( thf )2(C2H4PPh2)2Mo(CO)4]. thf and [ Yb ( thf )2 (C5H4PPh2)2Ni(CO)2]. The X-ray crystal structure of the last compound (triclinic, space group Pi, a 14.514(5), b 13.565(1), c 10.866(5) 93.11(2), β 104.65(3), γ 97.25(2)�, U 2045 � 3 , Z 2, 5141 data refined to R 0.031) reveals eight-coordinate ytterbium with a pseudo-tetrahedral arrangement of two thf ligands and the cyclopentadienyl ring centroids of two ή5 -diphenylphosphinocyclopentadienide ligands . The latter are also bonded through phosphorus to the Ni(CO)2 group, resulting in tetrahedral stereochemistry for nickel. Infrared spectroscopy suggests the presence of ytterbium- isocarbonyl bonding in solid [ Yb ( thf )(C2H4PPh2)2Z] [Z = Ni(CO)2 or Mo(CO)4].
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Ding, Shengda, Pokhraj Ghosh, Marcetta Y. Darensbourg et Michael B. Hall. « Interplay of hemilability and redox activity in models of hydrogenase active sites ». Proceedings of the National Academy of Sciences 114, no 46 (30 octobre 2017) : E9775—E9782. http://dx.doi.org/10.1073/pnas.1710475114.

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The hydrogen evolution reaction, as catalyzed by two electrocatalysts [M(N2S2)·Fe(NO)2]+, [Fe-Fe]+ (M = Fe(NO)) and [Ni-Fe]+ (M = Ni) was investigated by computational chemistry. As nominal models of hydrogenase active sites, these bimetallics feature two kinds of actor ligands: Hemilabile, MN2S2 ligands and redox-active, nitrosyl ligands, whose interplay guides the H2 production mechanism. The requisite base and metal open site are masked in the resting state but revealed within the catalytic cycle by cleavage of the MS–Fe(NO)2 bond from the hemilabile metallodithiolate ligand. Introducing two electrons and two protons to [Ni-Fe]+ produces H2 from coupling a hydride temporarily stored on Fe(NO)2 (Lewis acid) and a proton accommodated on the exposed sulfur of the MN2S2 thiolate (Lewis base). This Lewis acid–base pair is initiated and preserved by disrupting the dative donation through protonation on the thiolate or reduction on the thiolate-bound metal. Either manipulation modulates the electron density of the pair to prevent it from reestablishing the dative bond. The electron-buffering nitrosyl’s role is subtler as a bifunctional electron reservoir. With more nitrosyls as in [Fe-Fe]+, accumulated electronic space in the nitrosyls’ π*-orbitals makes reductions easier, but redirects the protonation and reduction to sites that postpone the actuation of the hemilability. Additionally, two electrons donated from two nitrosyl-buffered irons, along with two external electrons, reduce two protons into two hydrides, from which reductive elimination generates H2.
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ADURIZ, H. R., P. BODNARIUK, B. COQ et F. FIGUERAS. « ChemInform Abstract : Alumina-Supported Bimetallics of Palladium Alloyed with Germanium, Tin, Lead, or Antimony from Organometallic Precursors. Part 2. Gas-Phase Hydrogenation of 2-Methyl-1-buten-3-yne (Valylene) and 2-Methyl-1,3- butadiene (Isoprene). » ChemInform 22, no 27 (23 août 2010) : no. http://dx.doi.org/10.1002/chin.199127096.

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ADURIZ, H. « Alumina-supported bimetallics of palladium alloyed with germanium, tin, lead, or antimony from organometallic precursors II. gas-phase hydrogenation of 2-methyl-1-buten-3-yne (valylene) and 2-methyl-1,3-butadiene (isoprene) ». Journal of Catalysis 129, no 1 (mai 1991) : 47–57. http://dx.doi.org/10.1016/0021-9517(91)90008-r.

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Cooke, Paul A., Caroline O'Dowd, Michael G. S. Londesborough, Josef Holub, Bohumil Štı́br, Mark Thornton-Pett, William Clegg, Simon J. Teat et John D. Kennedy. « B-frame supported bimetallics. ‘Composite cluster’ compounds and the structures of [2,7-(η5-C5Me5)2-nido-2,7,8,6-Ir2CSB6H8] and its 9-chloro derivative. Synchrotron and conventional X-ray studies ». Journal of Organometallic Chemistry 614-615 (décembre 2000) : 57–60. http://dx.doi.org/10.1016/s0022-328x(00)00592-1.

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Thèses sur le sujet "2-Bimetallics"

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OMWENGA, JERSFREY OMWENGA. « Synthesis and Crystal Chemistry of Bimetallic Group II Nitride Fluorides ». Youngstown State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1534861452050001.

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Udumula, Venkata Reddy. « Synthesis, RNA Binding and Antibacterial Studies of 2-DOS Mimetics AND Development of Polymer Supported Nanoparticle Catalysts for Nitroarene and Azide Reduction ». BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/6031.

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Project I 2-Deoxystreptamine (2-DOS), the most conserved central scaffold of aminoglycosides, is known to specifically recognize the 5'-GU-'3 sequence step through highly conserved hydrogen bonds and electrostatic interactions within and without the context of aminoglycosides (Figure 1a). We proposed that a novel monomeric unnatural amino acid building block using 2-DOS as a template would allow us to develop RNA binding molecules with higher affinity and selectivity than those currently available. Conjugating two or more of the monomeric building blocks by an amide bond would introduce extra hydrogen bonding donors and acceptors that are absent in natural aminoglycosides and increase specificity of binding to a target RNA through a network of hydrogen bonds. In addition, the amide conjugation between the monomeric building blocks places two GU-base recognizing amines at 5 Å… distance, which is equal to the distance of neighboring base stacks in dsRNAs We hypothesized that targeting dsRNAs containing multiple consecutive 5'-GU-'3 sequence steps would become possible by connecting two or more of the monomeric building blocks by amide bonds. According to the proposed hypothesis, we designed three dimeric 2-DOS compounds connected by an amide bond. These three targets include the dimeric 2-DOS substrate connected by an amide bond, the dimeric 2-DOS containing the sugar moiety from Neamine, and a dimeric 2-DOS connected by a urea linker. These compounds were then tested for sequence specific binding against 8 different RNA strands, and for antibacterial activity against E. coli, actinobacter baumannii and klebsiella. Project II A dual optimization approach was used for to enhance the catalytic activity and chemoselectivity for nitro reduction. In this approach the composition of the nanoparticles and electronics effects of the polymer were studied towards nitro reduction. Bimetallic Ruthenium-Cobalt nanoparticles showed exceptional catalytic activity and chemoselectivity compared to monometallic Ruthenium nanoparticles. The electronic effects of the polymer also had a significant effect on the catalytic activity of the bimetallic nanoparticles. The electron-deficient poly(4-trifluoromethylstyrene) supported bimetallic nanoparticles undergo nitro reduction in 20 minutes at room temperature, whereas electron-rich poly(4-methylstyrene) and poly(4-methoxystyrene) supported bimetallic nanoparticles to longer reaction times to go to completion. Electronics of the polymers also effects the change in mechanism of nitroreduction. Polystyrene bimetallic Ruthenium-Cobalt nanoparticles showed excellent yields and chemoselectivity towards nitro functional group in the presence of easily reducible functional groups like alkenes, alkynes, allyl ethers, propargyl ethers. Monometallic ruthenium nanoparticles also showed excellent reactivity and chemoselectivity towards azide reduction in the presence of easily reducible functional groups. Interestingly monometallic ruthenium nanoparticles showed regioselective reduction of primary azides in the presence of secondary and benzylic azides, also aromatic azides can be selectively reduced in the presence of secondary azides. These polystyrene supported nanoparticles are heterogeneous and are easily separated from the reaction mixture and reused multiple times without significant of catalytic activity.
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Endot, N. B. « Selective hydrogenation of 5-hydroxymethylfurfural (HMF) to 2, 5-dimethylfuran (DMF) over Ru, Ni, and Co mono and bimetallic catalysts supported on carbon and carbon nanotube ». Thesis, University of Liverpool, 2017. http://livrepository.liverpool.ac.uk/3008300/.

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The main objective of this thesis is to develop better catalysts for the hydrogenation of 5- hydroxymethylfurfural, HMF into high quality liquid fuel 2, 5- dimethylfuran (DMF) or partly hydrogenating compounds. This could be achieved by exploiting the support effect and using CNTs to improve activity and developing mono- and bimetallic systems utilising less expensive metals like Nickel, Cobalt or Iron compared to noble metals like ruthenium and rhodium. Succeeding at this could be an economic incentive for the scale-up production of DMF. In addition, we envisaged the opportunity to be able to produce the metal catalyst and support in one simple step using a sugar and the metal salt and we studied the utilisation of carbon synthesised hydrothermally from glucose as a catalyst support using microwave techniques. The physical and chemical properties of the catalysts were characterised using such techniques as X-ray diffraction (XRD), temperature programmed reduction (TPR), inductively coupled plasma emission spectroscopy (ICP), hydrogen and carbon monoxide chemisorption, transition electron microscopy (TEM) and x-ray photoelectron spectroscopy (XPS). Hydrogenation of HMF to DMF was examined over monometallic and bimetallic Ru, Ni and Co supported on carbon and CNT at 150 °C (20 bar of H2). Among the monometallic catalysts supported on carbon, Ru catalysts exhibited the highest DMF yield up to 80 % in 3 hours followed by Ni and Co catalyst. This is because Ni and Co are not as good as Ru in the hydrogenolysis step in order to get to DMF. As a comparison to carbon, CNT as a support shows a remarkable improvement in the HMF conversion and DMF yield in a shorter reaction time. The effect is consistence for all the catalysts. A control test with only CNT showed a negligible activity which confirms that the enhancement is due to the presence of metal catalyst. HMF conversion of 100 % with 84 % DMF yield in 1 hr was achieved over 5 wt % Ru/CNT. The improvement of reactivity is attributed to the electronic effect of CNT derived from the curvature shape of CNT. This consequently enhanced the electron density of metal thus improving the adsorption of C=O bonds resulting in higher reactivity. We found that the promoting effect of the CNT support was universal to all catalyst tested, so that reasonably good Co and Ni catalysts could be obtained, particularly for the initial step of the reaction. The bimetallic system of RuCo and RuNi with specific molar ratios showed a significant improvement in reactivity compared to their monometallic counterparts, particularly considering the lower loading used. High yield of DMF was obtained even at low Ru content in a bimetallic catalyst without losing much DMF yield. 3.5 % RuCo/C 1:5 (0.6 % Ru) and 3.2 % RuNi 1:3 (0.7 % Ru) have better specific DMF yield as compared to 5% Ru/C and 5 % Ru/CNT. 4.2 % RuCo/CNT 1:2 with only 0.2 % loading of Ru showed the highest specific DMF yield. This finding is a positive outcome in order to reduce the dependent on the expensive noble metal without compromising the activity and the yield of desired product, in our case DMF. This proved the synergistic effect of this system. The only difference when different supports were used was that CNT improved the reaction rates however this is also lead to the formation of ring hydrogenation and ring opening products. Carbon has lower reaction rate however it gives better DMF yield. Finally, we demonstrated that one step microwave assisted synthesis of carbon supported catalysts is a promising technique to simultaneously synthesise catalyst as well as hydrothermal carbon in a shorter amount of time compared to the conventional hydrothermal and incipient wetness impregnation method.
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Hao, Bo. « Asymetric oxidation reactions catalyzed by chiral substituted polymers / nanoclusters ; synthesis of 6-(dimethylamino)-2-phenylisoindolin-1-one derivative ». Diss., 2018. http://hdl.handle.net/2097/38904.

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Doctor of Philosophy
Department of Chemistry
Duy H. Hua
The discovery of new methodologies to advance the fields of synthetic organic, nanoclusters, and polymer chemistry is critical in the asymmetric synthesis of organic compounds. Particularly, catalytic asymmetric oxidation reactions are economic. The oxidation reactions provide chiral molecules and additional functionality onto the molecules for functional group manipulation. New kinds of polymers, namely chiral-substituted poly-N-vinylpyrrolidinones (CSPVPs), stabilize the bimetallic nanoclusters such as Pd/Au or Cu/Au and induce chirality. These chiral polymers wrap around the nanometer-sized (~3 nm) bimetallic nanoclusters and catalyze a number of enantioselective oxidation reactions using oxygen or hydrogen peroxide as the oxidant. Cycloalkanediols were asymmetrically oxidized by 1 atm of oxygen gas to yield the corresponding hydroxyl ketone under the catalysis of Pd/Au (3:1) – CSPVP nanoclusters. Alkenes were oxidized by Pd/Au (3:1)-CSPVP nanoclusters under 2 atmospheric of oxygen in water to give the syn-dihydroxylated products in high chemical and excellent optical yields. Various cycloalkanes underwent regio- and enantio-selective C-H oxidation with Cu/Au (3:1)-CSPVP and 30% hydrogen peroxide to produce the corresponding chiral oxo-molecules in very good to excellent chemical and optical yields. We further discovered an enantioselective desymmetrization of , -dialkenyl-alkanols and , -dialkenyl-amino acid ethyl esters to give chiral disubstituted lactones and lactams, respectively. A number of medium-sized natural products and drugs were also oxidized regioselectively to give the corresponding mono-oxygenated products. A broad-spectrum predictive C-H oxidation of complex molecules is possible. Chapter 1 mainly discussed the synthesis and characterization of the new classes of chiral substituted PVP and bimetallic nanoclusters. Chapter 2 focus on various kind of oxidation reactions by the catalysis of CSPVP stabilized bimetallic nanoclusters. Among various bioluminescence assays, firefly luciferase based bioluminescence assays are popular due to their high specific activity, low background noise and ease of use. However, it has been found that some aromatic carboxylic acid substantially inhibited the firefly luciferase reporter enzyme’s activity. In order to study firefly luciferase inhibition and the proteins associated with inhibition mechanism, we designed two 6-(dimethylamino)-2-phenylisoindolin-1-one derivatives as probe molecules. The synthesis of one probe molecule is discussed in Chapter 3 and the further investigation of its inhibitory activity on firefly luciferase is being conducted by our collaborate.
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Chapitres de livres sur le sujet "2-Bimetallics"

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Liptrot, David J. « Group 1-Group 2 Bimetallic Alkyls and Hydrides ». Dans Group 2 Mediated Dehydrocoupling, 41–61. Cham : Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-21036-0_2.

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Gao, Yuanfeng, Hong Lv, Yongwen Sun, Han Yao, Ding Hu et Cunman Zhang. « Enhancement of Acidic HER by Fe Doped CoP with Bimetallic Synergy ». Dans Proceedings of the 10th Hydrogen Technology Convention, Volume 1, 465–74. Singapore : Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-99-8631-6_45.

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AbstractCompared to single metal site catalysis, the bimetallic synergistic strategy can exploit the complementary ability of different active sites for active species uptake and desorption to develop excellent catalysts. Pure phase metal phosphides are a disadvantage as a promising electrocatalyst for platinum-free hydrogen precipitation with either too strong or too weak adsorption of hydrogen. Here, synthetic Fe-doped CoP particles anchored with MWCNTs, which exhibited excellent catalytic performance for HER, required an overpotential of 123 mV to reach 10 mA cm−2, with a Tafel slope of 58.8 mV dec−1. It was found experimentally that Fe doping improved the conductivity of the catalyst regulated the electronic structure of CoP, and optimized the overall hydrogen adsorption energy of the catalyst. The difference in hydrogen adsorption strength of Fe, Co is used to break the symmetry constraint of single active center and improve the intrinsic activity of the catalyst, a strategy that can be used to guide the preparation of inexpensive and high performance catalysts.
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Pardasani, R. T., et P. Pardasani. « Magnetic properties of bimetallic manganese(II, II) complex with bis(2-hydroxy-1-naphthaldenyde)-oxaloyldihydrazone ». Dans Magnetic Properties of Paramagnetic Compounds, 910–11. Berlin, Heidelberg : Springer Berlin Heidelberg, 2017. http://dx.doi.org/10.1007/978-3-662-54228-6_517.

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Pardasani, R. T., et P. Pardasani. « Magnetic properties of bimetallic manganese(II, II) complex with bis(2-hydroxy-1-naphthaldenyde)-oxaloyldihydrazone ». Dans Magnetic Properties of Paramagnetic Compounds, 912–13. Berlin, Heidelberg : Springer Berlin Heidelberg, 2017. http://dx.doi.org/10.1007/978-3-662-54228-6_518.

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Pardasani, R. T., et P. Pardasani. « Magnetic properties of bimetallic manganese(II, II) complex with bis(2-hydroxy-1-naphthaldenyde)oxaloyldihydrazone ». Dans Magnetic Properties of Paramagnetic Compounds, 914–15. Berlin, Heidelberg : Springer Berlin Heidelberg, 2017. http://dx.doi.org/10.1007/978-3-662-54228-6_519.

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Pardasani, R. T., et P. Pardasani. « Magnetic properties of tetranuclear bimetallic (FeIII-GdIII)2 complex with 1,2-bis-(3-methoxysalicylidene)aminoethane ». Dans Magnetic Properties of Paramagnetic Compounds, Magnetic Susceptibility Data, Volume 3, 921–23. Berlin, Heidelberg : Springer Berlin Heidelberg, 2021. http://dx.doi.org/10.1007/978-3-662-62470-8_390.

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Pardasani, R. T., et P. Pardasani. « Magnetic properties of bimetallic heptanuclear cyano bridged iron(II)-copper(II) complex with tris(2-pyridylmethyl)amine ». Dans Magnetic Properties of Paramagnetic Compounds, 377–78. Berlin, Heidelberg : Springer Berlin Heidelberg, 2017. http://dx.doi.org/10.1007/978-3-662-53971-2_191.

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Pardasani, R. T., et P. Pardasani. « Magnetic properties of bimetallic heptanuclear cyano bridged iron(II)-copper(II) complex with tris(2-pyridylmethyl)amine ». Dans Magnetic Properties of Paramagnetic Compounds, 842–43. Berlin, Heidelberg : Springer Berlin Heidelberg, 2017. http://dx.doi.org/10.1007/978-3-662-53974-3_427.

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Pardasani, R. T., et P. Pardasani. « Magnetic properties of homo-bimetallic Co(II)2 complex with [N10] macrocyclic ligand modified with tetramide function ». Dans Magnetic Properties of Paramagnetic Compounds, Magnetic Susceptibility Data, Volume 7, 600–602. Berlin, Heidelberg : Springer Berlin Heidelberg, 2023. http://dx.doi.org/10.1007/978-3-662-65895-6_223.

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Pardasani, R. T., et P. Pardasani. « Magnetic properties of homo-bimetallic Ni(II)2 complex with [N10] macrocyclic ligand modified with tetramide function ». Dans Magnetic Properties of Paramagnetic Compounds, Magnetic Susceptibility Data, Volume 7, 805–7. Berlin, Heidelberg : Springer Berlin Heidelberg, 2023. http://dx.doi.org/10.1007/978-3-662-65895-6_298.

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Actes de conférences sur le sujet "2-Bimetallics"

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Divya, Shubhangi et Pranjal Chandra. « Bimetallic Copper/Zinc Metal Organic Framework-MoS2Nanohybrid based Electrochemical Sensor ». Dans 2024 IEEE BioSensors Conference (BioSensors), 01–04. IEEE, 2024. http://dx.doi.org/10.1109/biosensors61405.2024.10712708.

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Kleiser, Geremy, Michael Steinberg et Lalit Chhabildas. « Feasibility of an Explosive End-Projector for Conducting Shock Loading Experiments ». Dans ASME 2009 Pressure Vessels and Piping Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/pvp2009-77202.

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This paper focuses on examining the feasibility of using an explosive end-projector device to conduct shock loading experiments. The concept employs an explosive end-projector to accelerate a bonded bimetallic impactor toward a stationary target material in order to conduct complex shock loading experiments. A high-impedance material, tantalum, was specifically selected to generate high stresses in targets. The driver plate materials were varied to create an impedance spectrum from 2 to 4 which would encompass materials from aluminum to zirconium. Techniques for launching single density metal plates exist. [1] The objective of this paper is to further refine an existing explosive technique to launch bimetallic plates which would generate complex shock/reshock or shock/release waves when used as a impactor. Although a bimetallic impactor will generate complex wave loading within a target material upon impact, it must first survive intact the explosive shock acceleration stress history imposed during launch in order to obtain the terminal velocity for use as an impactor. Initial computational studies using the Lagrangian finite element code EPIC were promising. [2] Based on the concern of the plate spallation during launch [2], an air gap between explosive and the backside of the bimetallic plate was modeled to reduce the magnitude of the initial shock resulting from direct explosive-metal interaction and to further gain insight into its effects on pressure, terminal velocity, and planarity of the plate. Initially, a single, homogenous plate of aluminum was modeled to examine the effects of the air gap without the complication of bimetallic wave reverberation. The air gap did reduce the intensity of pressure by 30% with only a 4% loss in terminal velocity. Planarity was exacerbated by the air gap leading to increased warping. With the introduction of bimetallic plates and the corresponding wave reverberation pressure reductions ranged between 20% to 30% with corresponding losses in terminal velocity of between 5% to 7%. Planarity was improved for the configurations in which the high density material, tantalum, was on the free surface or impacting side of the impactor but warping increased when the order was reversed. This results from the low-impedance material serving as a buffer to allow quasi-isentropic and monotonic increase in loading of the tantalum plate. However, when the high density material was placed on the back side of the impactor, the loading history was reversed and the low density material was subjected to high pressures. Overall, the technique appears to be a feasible alternative for conducting shock loading experiments. The air gap reduces pressure with only a minimal loss in terminal velocity, and the air gap in conjunction with plate geometry changes appears to mitigate spall. The air gap does not improve planarity with the explosive end-projector design used in this investigation but optimized designs would improve the flexibility of the technique.
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Magerramova, Liubov, Boris Vasilyev, Ravil Nigmatullin et Vladimir Kinzburskiy. « Design of a Bimetallic Blisk Turbine for a Gas Turbine Engine and its Production Using Powder Metallurgy Methods ». Dans ASME Turbo Expo 2017 : Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gt2017-63560.

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One key engine component that defines the main engine characteristics is the wheel of a high-pressure turbine. One reasonable approach for increasing the efficiency of this type of turbine is to use blade shrouding. However, this shrouding also increases the centrifugal loading on the profile part of the blades, the lock connection, and the disk. One solution to this issue is to eliminate the lock connections, i.e. to create wheels of a blisk-type design. The bimetallic blisk was developed based on a wheel that has a lock connection for the disk and blades without shrouds. This study presents a redesign of the profile parts of the blades using computational fluid dynamics calculations, and a reintroduction of shrouds to the blade design. Connection of the blades to the disc involved a newly developed process based on powder metallurgy. The result is a bimetallic blisk consisting of single-crystal blades with shrouds and a disk consisting of a granulated heat-resistant nickel base alloy, connected by hot isostatic pressing. This bimetallic blisk satisfies the strength requirements and is detuned from the resonant frequencies. The weight is 7% lower for the developed design than for the prototype, and the turbine efficiency is increased by 2%.
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Yang, Y. P., F. W. Brust et J. Oh. « Creep Behavior of a Bimetallic Welded Joint in a Nuclear Piping System ». Dans ASME 2003 Pressure Vessels and Piping Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/pvp2003-2045.

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The information of the creep behavior of a thick welded joint is very important to secure the safety of high temperature service devices. The creep damage development and behavior are very complex; hence it is time consuming to practice the experiment and theoretical analyses. In this paper a simple accurate model was developed to analyze the creep behavior of weld metal and heat-affected zone on a thick bimetallic welded pipe. The pipe was made by welding an A508-class-2 carbon steel pipe to a 304 stainless steel pipe with a shielded metal arcwelding process using INCONEL 182 electrodes. Virtual fabrication technology weld modeling tools (VFT™) developed jointly by Battelle and Caterpillar was used to obtain welding-induced residual stress. The weld residual stress was read into the creep model as initial stress condition for creep analysis. A temperature 1000°F was applied on the bimetallic weld model with inside pressure and axial loading. The simulation results indicated that creep strains were not uniform through the weld joint due to weld residual stresses, materials creep behavior and geometry changes. Some stress and strain concentrations were found on the A508 steel near buttering region, which results in axial cracks.
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Aftandiliants, Yevhenii, Svyatoslav Gnyloskurenko, Helena Meniailo, Valerii Khrychikov et Viktor Lomakin. « Influence of K2ZrF6 and SiO2 on refining ability of flux for manufacturing bimetallic castings ». Dans 23rd International Scientific Conference Engineering for Rural Development. Latvia University of Life Sciences and Technologies, Faculty of Engineering and Information Technologies, 2024. http://dx.doi.org/10.22616/erdev.2024.23.tf061.

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Bimetallic material is considered as an advanced functional material due to the unique physical and mechanical properties varied over the layers. Formation of bimetallic castings with steel base greatly depends on diffusion coupling with the second material working layer at elevated temperatures. The common technological problem is to remove the oxide films from the solid steel surface while its heating prior pouring melt of the working layer. This work studies the protective refining fluxes matching the selected requirements of good wetting the surfaces of solidified metal, effective protection against oxidation in the working temperature range, easy separation after pouring liquid metal and high refining capacity for oxides. The most effective fluxes based on Na2B4O7 and B2O3 compounds were used. To improve their ability to enhance wetting, work of adhesion and reduce surface decarbonization addition of K2ZrF6 and SiO2 to the flux in the amount of 3-4 wt.% was proposed and investigated. It was established that such additions increased wettability up to 9 and 20%, respectively and reduced the average rate of decarburization in the temperature range from 800 to 1000 °С on 57 and 37%. The complete reduction of iron from scale on the steel surface was observed, while in the case of Na2B4O7 – B2O3 system it achieved 30-40% only. The mechanism explaining such a result is proposed to be due to the prevailing effect of zirconium in protecting the surface of the steel base from the oxidation and decarburization. The important result of the study is the recommendation of optimal flux composition (wt.%): Na2B4O7 – from 60 to 80; B2O3 – from 10 to 30; K2ZrF6 - from 3 to 4; SiO2 from 3 to 4. Thus, such flux could improve the production of steel based bimetallic castings and increase their properties.
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Hurst, Antony M., Louis C. W. Chang et Nak-Kyun Cho. « Comparative Study on Creep-Fatigue Damage Assessment Between R5 Procedures and a Full Inelastic Analysis ». Dans 2022 29th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/icone29-91707.

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Abstract This research aims to investigate the differences in structural integrity assessment results between R5 Volume 2/3 procedures and a detailed inelastic analysis. The membrane sidewall/roof bimetallic stub tube subjected to creep-fatigue loading is selected as an example. Based on a linear elastic analysis, the maximum equivalent stress is found to be at the weldment located at the top of the stub tube. The R5 Volume 2/3 procedures enhance the start of a dwell stress and inelastic strain ranges by applying a weld strain enhancement factor and a stress concentration factor, and the assessment predicts a total creep-fatigue damage of 54% for a 45 year life. As a comparison, a detailed inelastic analysis has been conducted for the same bi-metallic stub tube using an incremental, step-by-step analysis. Temperature dependent material properties are used to simulate stress-strain response and a user subroutine is employed for creep deformation. Assessment results for the detailed inelastic analysis confirm the weldment is similarly affected as indicated by the elastic analysis results but the comparable total predicted creep-fatigue damage is less than 35%. Cold eye review of both assessment results concluded that the significant deviation is attributed to the additional factors applied for the assessment of weldments, including weldment geometry, flaw effects and weld micro-cracking, as provided in the R5 Volume 2/3 procedures.
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Laws, A. D., Y. J. Chang, V. M. Bright et Y. C. Lee. « Thermal Conduction Switch for Thermal Management of Chip Scale Atomic Clocks ». Dans ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-14540.

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We report the first use of a bimetallic buckling disk as a thermal conduction switch. The disk is used to passively alter the thermal resistance of the package of a chip scale atomic clock. A vertical-cavity surface-emitting laser (VCSEL) and a cesium vapor cell, contained in the clock, must be maintained at 70±0.1°C even under an ambient temperature variation of -40°C to 50°C. A thermal test vehicle has been developed to characterize a sample package with a thermal conduction switch and has been modeled using Finite Element Analysis (FEA). Three cases are presented for the temperature control of the test vehicle under different load placements and environmental conditions: 1) the center resistor in a vacuum package; 2) the center resistor packaged in air; and 3) the side resistor in a vacuum package. At 38°C, the switch snaps upward to reduce the thermal resistance. As a result, the heating power needed to maintain the same temperature is increased from 118 to 200 mW for Case 1. Such a significant change of the thermal resistance demonstrates the effectiveness of the novel thermal switch. However, the switch becomes less effective with air filling the gap, as in Case 2. More interestingly, the switch is not effective at all if the side resistor's temperature is to be controlled as in Case 3.
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Ancelet, O., et S. Chapuliot. « Tensile Characterization of Narrow Gap Bimetallic Weld Ferritic-Austenitic Steel With a New Measurement System for Tensile Testing ». Dans ASME 2016 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/pvp2016-63637.

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Ferritic steel 2 ¼ Cr is a candidate material for future pressure component in nuclear fields. In order to validate this choice, it is necessary, firstly to verify that it is able to withstand the planned environmental and operating conditions, and secondly to check if it is covered by the existing design codes, concerning its procurement, fabrication, welding, examination methods and mechanical design rules. A large R&D program on 2 ¼ Cr steel has been undertaken at CEA and Areva in order to characterize the behavior of this material and of its welded junctions. In this frame, a new measurement system for tensile testing was developed in the LISN laboratory of the CEA (French atomic commission), in order to characterize the local behavior of the material during a whole tensile testing. Indeed, with the conventional measurement system (typically an extensometer), the local behavior of the material can only be determinate during the stable step of the testing. So, usually the behavior of the material during the necking step of the step is unknown. This new measurement is based on the use of some laser micrometers which allow measuring the minimum diameter of the specimen and the curvature radius during the necking phase with a great precision. Thanks to the Bridgman formula, we can evaluate the local behavior of the material until the failure of the specimen. This new system was used to characterize the tensile propriety of a bimetallic welded junction of 2 ¼ Cr steel and austenitic stainless steel 316L(N) realized with inconel filler metal. These works lead to propose a tensile curve for each materials of the welded junction at room temperature and the effect of postweld heat treatment.
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Rizwan, Mohsin, et Panos S. Shiakolas. « Towards the Realization of a Conveyor Platform for Microparts Employing a Deformable Surface ». Dans ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-87910.

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Various approaches ranging from micro-sized air-nozzles to direct manipulation through bimetallic actuators have been proposed to displace/orient sub-millimeter sized parts for automatic assembly of homogeneous and/or heterogeneous microdevices Keeping in view the micromanipulation requirements, based on the concept of active surface, a new approach for micromanipulation has been proposed by the authors which comprises of controlled deformation of a flexible continuous surface [1]. A single actuator system has limited micropart translocation capability and multiple sequential actuators need to be used if the required translocation distance is more than the capability of an actuator. For a single actuator system, the parameters of the system and their influence on the system output (translocation distance or travel distance) have already been discussed as function of the input frequency, actuator stroke, surface roughness and deformation wavelength [2]. In a multiactuator system, the subsequent actuators engage the micropart with a finite initial velocity and at some position relative to the actuator. Therefore, a sequential array of actuators exhibits a different set of overall operational characteristics. This manuscript describes the operational characteristics of sequential actuators towards a microconveyor system over a range of actuator frequencies and other system parameters and estimates the system output i.e. the micropart distance travelled or translocation. The discussion is based on a two actuator system with the conclusions generalized for a multi-actuator system.
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