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排序方式: 共有451条查询结果,搜索用时 31 毫秒
11.
From a range of preparative methods, three geometric isomers of bis(diphenylarsino)methane‐dichloroplatinum(II) have been isolated, viz. cis‐PtCl2(dpam), trans, trans‐Pt2Cl4(dpam)2 and cis, trans‐Pt2Cl4(dpam)2. Their structures were determined by single‐crystal X‐ray diffraction. 相似文献
12.
Afshin Zarghi Sayed M. Foroutan Alireza Shafaati Arash Khoddam 《Chromatographia》2007,66(9-10):747-750
A simple, rapid and sensitive HPLC method has been developed and validated for the analysis of letrozole in human plasma. The separation was achieved on a monolithic silica column using acetonitrile–phosphate buffer. A fluorescence detector was used for the quantitation with excitation and emission wavelengths at 230 and 295 nm. The assay enables the measurement of letrozole for therapeutic drug monitoring with a minimum quantification limit (LOQ) of 0.5 ng mL?1. The method involves a simple, one-step extraction procedure with complete recovery. Calibration was linear over the concentration range 0.5–80 ng mL?1. The coefficients of variation for inter-day and intra-day assay were found to be less than 8%. 相似文献
13.
Jennifer Albaneze-Walker Jerry A. Murry Arash Soheili Scott Ceglia Shawn A. Springfield Charles Bazaral Peter G. Dormer David L. Hughes 《Tetrahedron》2005,61(26):6330-6336
An efficient synthesis of a potent PDE IV inhibitor 1 is described. The synthesis is highlighted by two practical and efficient catalytic reactions: a highly selective catalytic palladium mediated carbonylation of the pyridine side chain and an efficient palladium-catalyzed Suzuki-Miyaura coupling of a chloropyridine-N-oxide. 相似文献
14.
N. Mohtat F. L. Cozens T. Hancock-Chen J. C. Scaiano J. McLean J. Kim 《Photochemistry and photobiology》1998,67(1):111-118
We have examined the behavior of radical pairs derived by hydrogen abstraction of triplet benzophenone and some of its derivatives from bovine serum albumin, human serum albumin and calf thymus DNA. They have been investigated by means of nanosecond laser flash photolysis techniques. The dynamics of radical pair behavior are shown to be sensitive to external magnetic fields; these effects are interpreted using the established model for the influence of magnetic fields on radical pairs in micellar aggregates, in which intersystem crossing of the radical pair is slowed by the external magnetic field. Our results indicate that proteins and DNA can confine the radicals for a sufficiently long period of time for spin evolution to be affected by external fields. In proteins the radical pair retains its geminate character ( i.e . remains confined) for about 0.5–1 μs. Interestingly, the magnetic field effects observed in proteins and in DNA seem to occur in distinct timescales; for example, for 2,3,4,5,6-pentafluorobenzophenone bound to DNA, the magnetic field alters the radical reactivity only over times ≤50 ns, suggesting poor confinement. The timescale for these effects can be increased by promoting Coulombic attraction between DNA and the radical precursor. Electron transfer interactions play a role in the case of DNA. 相似文献
15.
Tamoradi Taiebeh Mehraban-Esfandiari Bita Ghadermazi Mohammad Ghorbani-Choghamarani Arash 《Research on Chemical Intermediates》2018,44(2):1363-1380
Research on Chemical Intermediates - In the present research, a magnetically recoverable catalyst was easily prepared by anchoring nickel onto the surface of organically modified magnetite... 相似文献
16.
An environmentally benign aqueous protocol for the synthesis of 3,4-dihydropyrimidin-2-(1H)-ones and thiones promoted by a green catalyst,silica gel-supported L-pyrrolidine-2-carboxylic acid-4-hydrogen sulfate,has been developed.The use of nontoxic,thermally stable and inexpensive amino acid catalyst makes the process simple with minimal amount of chemical waste.Compared with classical Biginelli reaction conditions,this new method has the advantages of high yields and simple workup procedures. 相似文献
17.
Optimal free-defect synthesis of four-bar linkage with joint clearance using PSO algorithm 总被引:1,自引:0,他引:1
This paper presents the design of planar four-bar linkages free of order, branch and circuit defects, for the purpose of path generation, having clearances at one, two, three or all of its joints. Joint clearance is treated as a massless virtual link and its direction is known by the direction of the joint force. A Particle Swarm Optimization based algorithm is given here to solve this highly nonlinear optimization problem with some constraints, namely; the Grashof’s and free of the foregoing defects conditions. An example is included in which the optimal problem is solved for different cases; namely planar four-bar linkage having clearances at one, two, three, all of the joints and without clearance. For all the designs, the generated paths, the errors and the directions of the virtual links are plotted and are compared. Finally, we compare the optimal designs with reality. 相似文献
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