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121.
Nonlinear Dynamics - In this work, we demonstrate the application of the conserved-mass metamaterial concept to control the flutter onset in aircraft wings and mitigate their induced vibrations.... 相似文献
122.
Extending the previous work [1], we establish well-posedness results for a more general class of semilinear wave equations with exponential growth. First, we investigate the well-posedness in the energy space. Then, we prove the propagation of the regularity in the Sobolev spaces HS(IR^2) with s 〉 1. Finally, an ill-posedness result is obtained in HS(IR^2) for s 〈 1. 相似文献
123.
Yingying Wang Yan-Xin Chen Tarek Barakat Tian-Ming Wang Alain Krief Yu-Jia Zeng Marvin Laboureur Luca Fusaro Hong-Gang Liao Bao-Lian Su 《Journal of Energy Chemistry》2021,(5):141-151
The"one pot"simultaneous carbon coating and doping of TiO2 materials by the hydrolysis of TiCl4 in fructose is reported.The synergistic effect of carbon doping and coating of TiO2 to significantly boost textural,optical and electronic properties and photocurrent of TiO2 for high performance visible light H2 production from water splitting has been comprehensively investigated.Carbon doping can significantly increase the thermal stability,thus inhibiting the phase transformation of the Titania material from anatase to rutile while carbon coating can suppress the grain aggregation of TiO2.The synergy of carbon doping and coating can not only ensure an enhanced narrowing effect of the electronic band gap of TiO2 thus extending the absorption of photocatalysts to the visible regions,but also promote dramatically the separation of electron-hole pairs.Owing to these synergistic effects,the carbon coated and doped TiO2 shows much superior photocatalytic activity for both degradation of organics and photocatalytic/photoelectro chemical(PEC)water splitting under simulated sunlight illumination.The photocatalytic activity of obtained materials can reach 5,4 and 2 times higher than that of pristine TiO2,carbon doped TiO2 and carbon coated TiO2,respectively in the degradation of organic pollutants.The carbon coated and doped TiO2 materials exhibited more than 37 times and hundreds of times photocurrent enhancement under simulated sunlight and visible light,respectively compared to that of pristine TiO2.The present work providing new comprehensive understanding on carbon coating and doping effect could be very helpful for the development of advanced TiO2 materials for a large series of applications. 相似文献
124.
Maher A. El-Hashash Eman A. El-Bordany Magda I. Marzouk Tarek M. S. Nawar 《合成通讯》2016,46(24):2009-2021
As a part of ongoing studies in the synthesis of a variety of heterocycles of biological importance, we report here an efficient and convenient method for the synthesis of novel compounds from 6-iodo-2-isopropyl-4H-3,1-benzoxazin-4-one 1 as building block. The reaction of benzoxazinone 1 with various reagents such as diethylmalonate, sodium azide, and phosphorus pentasulfide yielded the compounds 2–5. The behavior of benzothiazin-4-thione 5 toward formamide and hydrazine hydrate was investigated, forming the compounds 6 and 7. The reaction of quinazolinone derivative 8 with β-D-glucose pentaacetate, ethyl 2-methyl-5-((1S,2R,3R)-1,2,3,4-tetrahydroxybutyl)furan-3-carboxylate, epichlorohydrin and benzenesulphonyl chloride afforded quinazolinone derivatives 9, 10, 12, and 13 respectively. The reaction of quinazolinone derivative 10 with acetic anhydride resulted in formation of the acylated compound 11. The behavior of quinazolinylacetohydrazide derivative 14 toward carbon electrophiles[16] has been investigated by its reaction with ethyl benzoylacetate, potassium thiocyanate, and phenyl isothiocyanate, affording the quinazolinone derivatives 15, 16, and 18, respectively. Treatment of compound 16 with sodium hydroxide followed by hydrochloric acid yielded the mercapto-triazole derivative 17. The structures of the newly synthesized compounds were confirmed by elemental analysis, infrared (IR), 1H NMR, 13C NMR, and mass spectra. The antimicrobial activities of some of the synthesized compounds were preliminarily evaluated. 相似文献
125.
Atef M. Amer Medhat El-Mobayed Abdel M. Ateya Tarek S. Muhdi 《Monatshefte für Chemie / Chemical Monthly》2002,133(1):79-88
Summary. It was found that aceanthrene quinone can be condensed with ethylenediamine, 1,2-diaminobenzene, 4-nitro-1,2-diaminobenzene,
1,2-diaminoanthrene quinone, and 4,5,6-triaminopyrimidine derivatives to give aceanthryleno[1,2-b]pyrazine and aceanthryleno[1,2-g]pteridine derivatives. Condensation of aceanthrene quinone with 2-aminoguanidine, semicarbazide, and thiosemicarbazide yielded
aceanthryleno[1,2-e]triazines, condensation with 6-hydrazinopyrimidine derivatives gave 3,4-aceanthrylenopyrimido[4,5-c]pyridazines. Reaction of aceanthrene quinone with 2-cyanoethanoic acid hydrazide afforded 10,11-dihydro-10-oxo-aceanthryleno[1,2-c]pyridazine-9-carbonitrile. Treatment of aceanthrene quinone with malononitrile and hydrazine hydrate resulted in 10-aminoaceanthryleno[1,2-c]pyridazine-9-carbonitrile. The antibacterial effects of the prepared compounds were tested. Three of the compounds were tested
against 60 cancer types.
Received May 6, 2001. Accepted June 5, 2001 相似文献
126.
Mamdouh S. Masoud Ahmed M. Hindawey Ali El-Dissouky Gamal B. Mohamed Tarek M. Abd El-Fattah 《Transition Metal Chemistry》1991,16(2):181-184
Summary The syn-2-picolyl phenyl ketoxime (HL1) and the syn-2-quinaldyl phenyl ketoxime (HL2) give [M(HL)LX], [M(HL)2X2] and [ML] solid complexes (M=Co, Ni and Cu; X=Cl–, Br– and NO
3
–
which have been characterized by elemental analysis, room temperature magnetic moments and electronic and i.r. spectral measurements. 相似文献
127.
Kamal Y.?El-BaradieEmail author Tarek M.?Fayed Ibrahim M.?El-Mehasseb 《Monatshefte für Chemie / Chemical Monthly》2005,136(7):1157-1169
Summary. Mono- and homobinuclear complexes of Mn(II), Co(II), Ni(II), and Cu(II) with phthalein purple are prepared and characterized by elemental analysis, thermal studies (TGA and DTA), spectral methods (IR, UV/Vis, and ESR), magnetic moment determination, and electrochemical reduction (DC polarography at DME and CV at HMDE). Thermal degradation of the complexes was studied by TGA and DTA where some thermodynamic parameters were determined. The mode of bonding and geometry of the complexes were determined from the spectral studies. Magnetic moment values showed some antiferromagnetism in the homobinuclear complexes. The reduction of the metal ions proceeds to the metallic state along an irreversible process. 相似文献
128.
New selective and sensitive Spectrophotometric methods for quinone determination are described. Quinone samples are treated with either methanolic solution of rhodanine, fluorene in ammoniacal media or aqueous semicarbazide hydrochloride solution. Semicarbazide is the most sensitive reagent for the determination of 1,4-benzoquinone, 1,4-naphthoquinone and 2-methyl-1,4-naphthoquinone. Quinones substituted with electron withdrawing groups are better determined using rhodanine. The average recovery is 99.1%, 98.7% and 99.2% using rhodanine, fluorene and semicarbazide as reagents, respectively. 相似文献
129.
A new series of metal complexes containing Co(II), Pd(II), Fe(III) chloride and Cu(II) salts (chloride, bromide, sulphate and perchlorate) have been prepared with Schiff base ligand ( HL ). The synthesized compounds were elucidated using elemental analyses, spectral techniques, molar conductance, magnetic measurements and thermogravimetric studies. The analytical data established (1 M:1 L) stoichiometry for complexes ( 1 ), ( 2 ), ( 4 ), ( 6 ) and ( 7 ) as well as (1 M:2 L) and (2 M:3 L) stoichiometry for complexes ( 5 ) and ( 3 ), respectively. As a result, the ligand HL coordinates in complexes ( 1 ), ( 2 ), ( 4 ), ( 6 ) as a monobasic tridentate ONN moiety via the oxygen atom of the deprotonated phenolic OH, the nitrogen atoms of the azomethine and the imine group in pyrazolopyridine ring. While, it behaves as a neutral bidentate in complexes ( 3 , 7 ), chelates via oxygen and nitrogen atoms of enolic OH and azomethine groups. Also, in complex ( 5 ) Cu2+ ion binds via NO sits of two ligand molecules in its monobasic and neutral forms. The magnetic moment and electronic spectral data proposed octahedral structure for complexes ( 2 , 3 and 7 ) as well as triagonal bipyramidal and square pyramidal geometry for complexes ( 1 and 4 ), while, chelates ( 5 ) and ( 6 ) possess square planar geometry. TG/DTG studies confirmed the chemical formula for these complexes and established the thermal decomposition processes ended with the formation of metal or metal oxides contaminated with carbon residue. An axial electron spin resonance spectra were suggested for Cu(II) complexes pointing to 2B1g as a ground state with hyperfine structure for complex ( 4 ). In vitro antibacterial and antioxidant activities were performed for HL ligand and its metal complexes. The biological studies indicate that complex ( 3 ) has better antibacterial activity compared to the ligand and the other complexes. 相似文献
130.