排序方式: 共有93条查询结果,搜索用时 15 毫秒
61.
Alper Tolga Çolak Okan Zafer Ye?ilelGönül Pamuk Handan GünayOrhan Büyükgüngör 《Polyhedron》2011,30(6):1012-1022
Three Co(II) and Cu(II)-pyridine-2,5-dicarboxylate (pydc) proton transfer compounds with 1,4-butanediamine (ben) and 2,2-dimethylpropane-1,3-diamine (dmpen), trans-(H2ben)[Co(pydc)2(H2O)2]·4H2O (1), trans-(H2dmpen)[Co(pydc)2(H2O)2]·2H2O (2) and (H2ben)2[Cu2(μ-pydc)4(H2O)2] (3) have been synthesized and characterized by the methods of elemental, spectroscopic (IR and UV-Vis), thermal (TG/DTG, DTA) analysis, magnetic measurement and single crystal X-ray diffraction. The crystallographic analysis revealed that the complexes consist of [Co(pydc)2(H2O)2]2− anion, bis(protonated) diamine cation (H2ben for 1 and H2dmpen for 2) and four and two crystal water molecules, respectively. The Co(II) ions are coordinated by two pydc and two aqua ligands. The bis(deprotonated) pydc ligands coordinate to the Co(II) ions through the nitrogen atom of pyridine ring and the oxygen atom of carboxylate group, creating a chelate ring. The distorted octahedral geometries are completed by two trans aqua ligands at axial positions. The molecular structure of the complex 3 consists of dinuclear [Cu2(μ-pydc)4(H2O)2]4− units and bis(protonated) 1,4-butanediammonium cation. In the structure, each Cu(II) ion is coordinated by two nitrogen and two oxygen atoms from two pydc ligands and one oxygen atom from aqua ligand, forming a distorted square pyramidal geometry. 相似文献
62.
Tarnkappen, die Menschen unsichtbar machen, galten jahrtausendelang als unerreichbarer Mythos. Unlängst konnten wir am Karlsruhe Institute of Technology gemeinsam mit Kollegen aus London jedoch erstmals eine dreidimensionale optische Tarnkappe herstellen und deren Funktion mit Hilfe eines optischen Mikroskops direkt experimentell nachweisen. 相似文献
63.
Alper Tolga Çolak Murat Taş Gazi İrez Okan Zafer Yeşilel Dr. Orhan Büyükgüngör 《无机化学与普通化学杂志》2007,633(3):504-508
The 2‐phenyl‐2‐(1‐hydroxyiminoethyl)‐1,2,3,4‐tetrahydroquinazoline (HL) and its NiII complex have been prepared and characterized by spectral method (FT‐IR, NMR (13C and 1H), UV‐vis.), elemental analysis, magnetic susceptibility and thermal analysis (TG, DTA) techniques. The crystal structures of HL and NiII complex were also determined by the single crystal X‐ray diffraction. The HL and NiII complex crystallizes in the monoclinic and triclinic, space groups P21/c and , respectively. The complex was occurred by the elimination of 1 mole of 2‐aminobenzylamine from the 2 moles of the HL after the ring opening reaction by the NiII attack. Crystallographic study reveal that NiII atom has a square planer geometry being coordinated by four nitrogen atoms of HL. Two thermal processes of the HL and NiII complex can occur in TG and DTA curves. 相似文献
64.
We show, using a simple example, that the First-In-First-Out (FIFO) policy can be unstable in a system with arbitrarily low load. Our proof is based on the observation that the special structure of the example we use allows us to establish stability using a much simpler queueing system. 相似文献
65.
Tolga Yarman 《Foundations of Physics Letters》2006,19(7):675-693
Herein we present a whole new approach that leads to the end results of the general theory of relativity via just the law
of conservation of energy (broadened to embody the mass and energy equivalence of the special theory of relativity) and quantum
mechanics. We start with the following postulate.
Postulate: The rest mass of an object bound to a celestial body amounts less than its rest mass measured in empty space, and this, as
much as its binding energy vis-á-vis the gravitational field of concern. 相似文献
66.
Jad C. Halimeh Tolga Ergin Nicolas Stenger Dr. Martin Wegener Prof. Dr. 《Physik in unserer Zeit》2010,41(4):170-175
Die Transformationsoptik erlaubt Verformungen des optischen Raums, die denen der Raumzeit in der Allgemeinen Relativitätstheorie bei Anwesenheit von Materie ähneln. Von Fata Morganas ist der Effekt kontinuierlich veränderlicher Brechzahlprofile vertraut. Doch erst die Theorie der Transformationsoptik erlaubt die systematische Entwicklung völlig neuer optischer Funktionen. Computersimulationen des Karlsruhe Institute of Technology zeigen, wie eine Tarnkappe und eine kugelförmige Strahlumlenkung funktionieren könnten – zwei Beispiele für die ungeahnten prinzipiellen Möglichkeiten der Transformationsoptik. Die experimentelle Umsetzung im optischen Spektralbereich stellt allerdings noch eine große Herausforderung dar. 相似文献
67.
Tolga Etgü 《Geometriae Dedicata》2008,132(1):53-63
As an application of the construction of open books on plumbed 3-manifolds, we construct elliptic open books on torus bundles
over the circle. In certain cases these open books are compatible with Stein fillable contact structures and have minimal
genus.
相似文献
68.
A three dimensional analytical model for crawl stroke swimming is developed in which the swimmer is modeled as a body and two arms connected to the body at the shoulder joints. Each arm is assumed to consist of three segments. The numerical results obtained from the model are compared with the results of two sets of experiments performed. In the first series of experiments, the tether forces developed in crawl stroke swimming are measured and a linear correlation between the tether force and the stroke rate is obtained. In the second series of experiments, untethered crawl stroke swimming for different arm position angles is recorded. The results are presented in graphical forms and the effect of stroke rate on swimming velocity is discussed. 相似文献
69.
The lifetimes of the hydroxyl stretch fundamentals of two methanol isotopomers, MeOH and MeOD, in carbon tetrachloride solvent are calculated through the use of the perturbative Landau-Teller and fluctuating Landau-Teller methods. Examination of these systems allows for insight into the nature of the vibrational couplings that lead to intramolecular vibrational energy transfer. While both systems display energy transfer to nearly degenerate modes, MeOD also displays strong coupling to an off-resonant vibration. The relaxation of MeOH and MeOD occurs through transitions involving a total change in the vibrational quanta of 4 and 3, respectively. We calculate vibrational energy relaxation lifetimes of 4-5 ps for MeOH and 2-3 ps for MeOD that agree well with the experimentally determined values. 相似文献
70.
Murat Oğuz Tolga Bektaş Julia A Bennell Jörg Fliege 《The Journal of the Operational Research Society》2016,67(8):1080-1096
This paper presents a general modelling framework for restricted facility location problems with arbitrarily shaped forbidden regions or barriers, where regions are modelled using phi-objects. Phi-objects are an efficient tool in mathematical modelling of 2D and 3D geometric optimization problems, and are widely used in cutting and packing problems and covering problems. The paper shows that the proposed modelling framework can be applied to both median and centre facility location problems, either with barriers or forbidden regions. The resulting models are either mixed-integer linear or non-linear programming formulations, depending on the shape of the restricted region and the considered distance measure. Using the new framework, all instances from the existing literature for this class of problems are solved to optimality. The paper also introduces and optimally solves a realistic multi-facility problem instance derived from an archipelago vulnerable to earthquakes. This problem instance is significantly more complex than any other instance described in the literature. 相似文献