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601.
602.
Javad Zolgharnein Hoomayon Tahmasebi Morteza Habibi Saeid Amani 《Journal of inclusion phenomena and macrocyclic chemistry》2004,49(3-4):231-234
The complexation of some alkali and alkaline earth cations with18-crown-6(18C6), dibenzo-18-crown-6 (DB18C6), dicyclohexyl-18-crown-6 (DCY18C6), and dibenzopyridino-18-crown-6 (DBPY18C6) in a methanol solution has been studied by a competitive potentiometric titration using Ag+/Ag electrode as a probe. The stoichiometry and stability constants of the resulting complexes have been evaluated by the MINIQUAD program. The stoichiometry for all resulting complexes was 1:1. The order of stability of Ag+ complexes with desired crown ethers varied as DBPY18C6 > DCY18C6 > 18C6 > DB18C6.The stability of the resulting complexes for each of these crown ethers varies in the order ofK+ > Na+ and Ba2+ > Sr2+ > Ca2+ > Mg2+.For each of the used metal ions the major sequence of the stability constants of the resulting complexes varies as DCY18C6 > 18C6 > DB18C6 > DBPY18C6 with minor exceptions. 相似文献
603.
As a counterpart to best approximation in normed linear spaces, best coapproximation was introduced by Franchetti and Furi.
In this paper, we shall show that if M is a separable, coproximinal subspace of X satisfying some additional conditions, then L
1 (S, M) is coproximinal in L
1(S, X).
相似文献
604.
605.
606.
In this research, potassium permanganate in the presence of a catalytic amount of [bmim]Br under solvent free conditions is used as an efficient and chemoselective method for oxidative cleavage of some oximes to corresponding carbonyl compounds. This experiment was carried out in mild conditions without any further oxidation of aldehydes to corresponding acids. 相似文献
607.
Jamshid Sabbaghzadeh Parvaneh Jafarkhani Siamak Dadras Mohammad Javad Torkamany 《Applied Physics A: Materials Science & Processing》2009,94(2):293-297
Synthesis of multi-wall carbon nanotubes in a 1473 K furnace using a copper vapor laser (CVL) is reported. The operating parameters
of this laser, i.e. a high fluence at the focal point and an extremely high frequency of 10 kHz, distinguished it from common
laser sources in the synthesis of CNTs. Therefore, the unexpected experimental findings, the formation of MWNTs instead of
the generally reported SWNTs, would be verified by these two notable parameters. Electron microscopy beside Raman spectroscopy
illustrates the presence of multi-wall carbon nanotubes in the resulting product. 相似文献
608.
Inverse dynamics of a general model of a spherical star-triangle (SST) parallel manipulator (Enferadi and Akbarzadeh Tootoonchi,
Robotica 27:663–676, 2009) is the subject of this paper. This manipulator is of type 3-RRP, has good accuracy and relatively a large workspace which
is free of singularities (Enferadi and Akbarzadeh Tootoonchi, Robotica, Revised paper, 2009). First, inverse kinematics utilizing the angle axis representation is solved. Next, velocity and acceleration analysis as
well as link Jacobian matrices are obtained in invariant form. Finally, a systematic approach based on the principle of virtual
work and the concept of link Jacobian matrices is presented. This method allows elimination of constraint forces and moments
at the passive joints from motion equations. It is shown that the dynamics of the manipulator can be reduced to solving a
system of three linear equations with three unknowns. Moreover, a computational algorithm for solving the inverse dynamics
is developed. Two examples with different trajectories for the moving spherical platform are presented and motor torques are
obtained. Results are verified using a commercial dynamics modeling package. 相似文献
609.
Azizian J Mohammadi AA Karimi AR Mohammadizadeh MR 《The Journal of organic chemistry》2005,70(1):350-352
KAl(SO(4))(2).12H(2)O is found to catalyze efficiently the stereoselective one-pot three-component cyclocondensation of homophthalic anhydride, aldehydes, and amines under mild conditions to afford the corresponding cis-isoquinolonic acids in good yields. 相似文献
610.
This study reports the development of a production scheduling system for the integrated management of production in large-scale, high-volume electronic assembly lines. The development of the system incorporates control and planning considerations by addressing the interaction of various subsystems. Stochastic and deterministic aspects of the problem environment are appropriately handled via relevant simulation and analytic models. By effecting a hierarchical breakdown of the problem environment, the system produces information used in practical decision making for production planning and scheduling. Procedures used encompass and address considerations for management of work-in-process, optimization of the various subsystems' performance, minimization of setup time effect, and inventory carrying costs. 相似文献