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排序方式: 共有119条查询结果,搜索用时 15 毫秒
81.
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83.
Nazario Lopez Andrey V. Prosvirin Dr. Hanhua Zhao Dr. Wolfgang Wernsdorfer Dr. Kim R. Dunbar Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(42):11390-11400
A series of isostructural compounds with formula [M(TCNQF4)2(H2O)6]TCNQF4 ? 3 H2O (M=Tb ( 1 ), Y ( 2 ), Y:Tb (74:26) ( 3 ), and Y:Tb (97:3) ( 4 ); TCNQF4= tetrafluorotetracyanoquinodimethane) were prepared and their magnetic properties investigated. Compounds 1 , 3 , and 4 show the beginning of a frequency‐dependent out‐of‐phase ac signal, and decreasing intensity of the signal with decreased concentration of TbIII ions in the diluted samples is observed. No out‐of‐phase signal was observed for 2 , an indication that the behavior of 1 , 3 , and 4 is indicative of slow paramagnetic relaxation of TbIII ions in the samples. A more detailed micro‐SQUID study at low temperature revealed an interplay between single‐molecule magnetic (SMM) behavior and a phonon bottleneck (PB) effect, and that these properties depend on the concentration of diamagnetic yttrium ions. A combination of SMM and PB phenomena was found for 1 , whereby the PB effect increases with increasing dilution until eventually a pure PB effect is observed for 2 . The PB behavior is interpreted as being due to the presence of a “sea of organic S=1/2 radicals” from the TCNQF4 radicals in these compounds. The present data underscore the fact that the presence of an out‐of‐phase ac signal may not, in fact, be caused by SMM behavior, particularly when magnetic metal ions are combined with organic radical ligands such as those found in the organocyanide family. 相似文献
84.
A machine design is described and results given for testing specimens of polymethyl methacrylate, treated in different conditions.Lenin Komsomol Riga Institute of Civil-Aviation Engineers. Translated from from Mekhanika Polimerov, No. 5, pp. 952–955, September–October, 1973. 相似文献
85.
Karadas F Schelter EJ Prosvirin AV Bacsa J Dunbar KR 《Chemical communications (Cambridge, England)》2005,(11):1414-1416
A high spin molecular square of square pyramidal Co(II) and tetrahedral Mn(II) corners exhibiting an overall S= 4 ground state has been crystallized and its magnetic properties investigated. 相似文献
86.
O. A. Kharitonova A. V. Prosvirin Yu. G. Galyametdinov I. V. Ovchinnikov 《Russian Chemical Bulletin》1996,45(9):2213-2215
Complexes of the composition L(LH)2Ln(NO3)2 (Ln = La, Dy, Gd, Er, Eu, or Tb) were obtained by the reaction of -aminovinyl ketone (LH) with rare earth metal nitrates. All the compounds synthesized are thermotropic liquid crystals having the smectic SA phase. The values of magnetic anisotropy of these complexes measured by magnetic birefringence are fairly high.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2331–2333, September, 1996. 相似文献
87.
Lopez N Zhao H Prosvirin AV Chouai A Shatruk M Dunbar KR 《Chemical communications (Cambridge, England)》2007,(44):4611-4613
Removal of methanol molecules from the interstices of a metal-organic framework based on a 2-D hexagonal Mn(II)-TCNQF(4) net results in stronger magnetic interactions and leads to a glassy magnetically ordered state; the magnetic behavior can be reversibly cycled upon solvation-desolvation of the material. 相似文献
88.
Karadas F Schelter EJ Shatruk M Prosvirin AV Bacsa J Smirnov D Ozarowski A Krzystek J Telser J Dunbar KR 《Inorganic chemistry》2008,47(6):2074-2082
The syntheses, structures, and magnetic properties of a series of tetranuclear cyanide-bridged compounds are reported. This family of molecular squares, [{M(II)Cl2}2{Co(II)(triphos)(CN)2}2] (M = Mn ([CoMn]), Fe ([CoFe]), Co ([CoCo]), Ni ([CoNi]), and Zn ([CoZn]), triphos = 1,1,1-tris(diphenylphosphinomethyl)ethane), has been synthesized by the reaction of Co(II)(triphos)(CN)2 and MCl2 (M = Mn, Co, Ni, Zn) or Fe4Cl8(THF)6 in a CH2Cl2/EtOH mixture. These complexes are isostructural and consist of two pentacoordinate Co(II) and two tetrahedral M(II) centers. The resulting molecular squares are characterized by antiferromagnetic coupling between metal centers that generally follows the spin-coupling model S total = SM(II)1 - SCo1 + SM(II)2 - SCo2. Magnetic parameters for all the complexes were measured using SQUID magnetometry. Additionally, [CoZn] and [CoMn] were studied by both conventional and high-frequency and high-field electron paramagnetic resonance. 相似文献
89.
I. S. Mashkovsky P. V. Markov G. O. Bragina G. N. Baeva A. V. Bukhtiyarov I. P. Prosvirin V. I. Bukhtiyarov A. Yu. Stakheev 《Kinetics and Catalysis》2017,58(4):471-479
The structure of the Pd–Zn/α-Al2O3 catalyst, which was prepared by a joint impregnation method, was studied. According to XRD analysis data, supported intermetallic Pd–Zn particles were formed in a temperature range of 200–600°C. At 600°C, the crystal lattice of substitutional solid solution based on Pd (FCC) was finally rearranged into the tetragonal lattice of Pd–Zn. A shift of the Pd3d 5/2 line in the XPS spectrum indicated the formation of the Pd–Zn intermetallic compound. 相似文献
90.
V. Z. Radkevich S. G. Khaminets O. A. Samoilenko I. G. Paplevko I. P. Prosvirin A. A. Dubkov L. N. Grishchenko 《Russian Journal of Applied Chemistry》2017,90(2):225-235
The influence exerted by the conditions of oxidation and calcination in an inert medium on the properties of Karbopon and Busofit activated carbon fibers were studied using a set of physicochemical methods. The maximal concentration of thermally stable phenol groups in Busofit is reached by its oxidation with a 20% aqueous HNO3 solution, followed by calcination in an inert medium at 500°С for 1.5 h. Experiments with catalysts supported on Busofit samples functionalized with 20% HNO3 have shown that palladium supported on Busofit that was calcined at 500°C after oxidative treatment is characterized by monodisperse nanocluster distribution. The prepared catalysts containing 1 wt % Pd exhibit higher activity in oxidation of carbon monoxide than their presently known analogs do. 相似文献