Особливості реалізації графічного конвеєру при візуалізації тривимірних моделей приміщень університету

В більшості систем комп‘ютерної графіки застосовується графічний конвеєр – логічна група послідовно виконуваних обчислень (етапів), які в результаті дають синтезовану сцену на екрані комп‘ютера. Серед основних – етапи геометричних перетворень та візуалізації. Результат виконання кожного з цих етапів впливає на кінцевий вигляд синтезованої сцени, тому їх коректне завершення є необхідною умовою отримання якісного зображення

Slow Dynamics of the Magnetization in One-Dimensional Coordination Polymers: Single-Chain Magnets

Slow relaxation of the magnetization (i.e., “magnet-like” behavior) in materials composed of magnetically isolated chains was observed for the first time in 2001. This type of behavior was predicted in the 1960s by Glauber in a chain of ferromagnetically coupled Ising spins (the so-called Glauber dynamics). In 2002, this new class of nanomagnets was named single-chain magnets (SCMs) by analogy to single-molecule magnets that are isolated molecules displaying related superparamagnetic properties. A long-range order occurs only at T = 0 K in any pure one-dimensional (1D) system, and thus such systems remain in their paramagnetic state at any finite temperature. Nevertheless, the combined action of large uniaxial anisotropy and intrachain magnetic interactions between high-spin magnetic units of the 1D arrangement promotes long relaxation times for the magnetization reversal with decreasing temperature, and finally at significantly low temperatures, the material can behave as a magnet. In this Forum Article, we summarize simple theoretical approaches used for understanding typical SCM behavior and some rational synthetic strategies to obtain SCM materials together with representative examples of SCMs previously reported

Slow Dynamics of the Magnetization in One-Dimensional Coordination Polymers: Single-Chain Magnets

Slow relaxation of the magnetization (i.e., “magnet-like” behavior) in materials composed of magnetically isolated chains was observed for the first time in 2001. This type of behavior was predicted in the 1960s by Glauber in a chain of ferromagnetically coupled Ising spins (the so-called Glauber dynamics). In 2002, this new class of nanomagnets was named single-chain magnets (SCMs) by analogy to single-molecule magnets that are isolated molecules displaying related superparamagnetic properties. A long-range order occurs only at T = 0 K in any pure one-dimensional (1D) system, and thus such systems remain in their paramagnetic state at any finite temperature. Nevertheless, the combined action of large uniaxial anisotropy and intrachain magnetic interactions between high-spin magnetic units of the 1D arrangement promotes long relaxation times for the magnetization reversal with decreasing temperature, and finally at significantly low temperatures, the material can behave as a magnet. In this Forum Article, we summarize simple theoretical approaches used for understanding typical SCM behavior and some rational synthetic strategies to obtain SCM materials together with representative examples of SCMs previously reported

Synthesis Crystal Structure and Magnetic Properties of the Trinuclear Nickel(II) Complex Bis[(μ-thiocyanato-<i>N</i>)bis(μ-pyridazine-<i>N</i>¹,<i>N</i>²)bis(thiocyanato-<i>N</i>)(pyridazine-<i>N</i>¹)nickel(II)- <i>N</i>,<i>N</i>¹,<i>N</i>¹‘]nickel(II)

Synthesis Crystal Structure and Magnetic Properties of the Trinuclear Nickel(II) Complex Bis[(μ-thiocyanato-N)bis(μ-pyridazine-N1,N2)bis(thiocyanato-N)(pyridazine-N1)nickel(II)- N,N1,N1‘]nickel(II

Novel Three-Dimensional Cage Assembly of a μ₄-Carbonato-Bridged Cobalt(II) Compound [Co₂(bpm)(H₂O)₂(CO₃)(OH)]NO₃·4H₂O

Novel Three-Dimensional Cage Assembly of a μ4-Carbonato-Bridged Cobalt(II) Compound [Co2(bpm)(H2O)2(CO3)(OH)]NO3·4H2

Self-Assembly of the Hexabromorhenate(IV) Anion with Protonated Benzotriazoles: X‑ray Structure and Magnetic Properties

Two novel ReIV compounds of formulas [HBTA]2­[ReIVBr6] (1) and [HMEBTA]2­[ReIVBr6] (2) [BTA = 1H-benzotriazole and MEBTA = 1-(methoxy­methyl)-1H-benzotriazole] have been synthesized and magneto-structurally characterized. 1 and 2 crystallize in the triclinic system with space group P1̅. In both compounds, the rhenium ion is six-coordinate, bonded to six bromo ligands in a regular octahedral geometry. Short ReIV–Br···Br–ReIV contacts, π–π stacking, and H-bonding interactions occur in the crystal lattice of both 1 and 2, generating novel supramolecular structures based on the ReIV. The different dispositions of the cations and the intermolecular Br···Br contacts in 1 and 2 play an important structure–property role, with the magnetic properties of 1 and 2 revealing a significant antiferromagnetic coupling between ReIV ions through intermolecular Br···Br interactions. In 1, these interactions account for a maximum in the magnetic susceptibility at ca. 10 K

Weak Ferromagnetism in Chiral 3-Dimensional Oxalato-Bridged Cobalt(II) Compounds. Crystal Structure of [Co(bpy)₃][Co₂(ox)₃]ClO₄

Weak Ferromagnetism in Chiral 3-Dimensional Oxalato-Bridged Cobalt(II) Compounds. Crystal Structure of [Co(bpy)3][Co2(ox)3]ClO4</sub

Ferromagnetic Coupling Through the End-to-End Thiocyanate Bridge in Cobalt(II) and Nickel(II) Chains

The preparation, spectroscopic characterization, and X-ray crystal structure of two novel one-dimensional compounds of formula [M^II(tppz)­(NCS)­(μ-1,3-NCS)]_<i>n</i> [tppz = 2,3,5,6-tetrakis­(2-pyridyl)­pyrazine and M = Co­(<b>1</b>) and Ni (<b>2</b>)] are reported. <b>1</b> and <b>2</b> are isomorphous compounds, and they crystallize in the <i>P</i>2₁/<i>n</i> space group. Their structures are made up of zigzag chains of cobalt­(II) (<b>1</b>) and nickel­(II) ions (<b>2</b>) bridged by single end-to-end thiocyanate groups with a tridentate <i>tppz</i> molecule and a terminally bound thiocyanate-<i>N</i> ligand achieving distorted MN₅S octahedral surroundings around each metal center. The main source of the distortion of the ideal octahedron is due to the geometrical constraints issued from the occurrence of two fused five-member chelate rings of the tridentate <i>tppz</i> ligand, the values of the N–M–N bond angles covering the range 75.58(9)–78.66(9)°. The M–N bond lengths vary in the range 2.025(3)–2.116­(29 (<b>1</b>) and 2.001(2)–2.079(2) Å (<b>2</b>), and they are shorter than the M–S bond distance [2.6395(10) (<b>1</b>) and 2.5225(9) Å (<b>2</b>)]. The values of the intrachain metal–metal separation are 6.4197(7) (<b>1</b>) and 6.3257(5) Å (<b>2</b>). The magnetic properties of <b>1</b> and <b>2</b> have been investigated in the temperature range 1.9–300 K. Both compounds exhibit intrachain ferromagnetic interactions with values of the magnetic coupling (<i>J</i>) of +4.60 (<b>1</b>) and +7.82 cm^–1 (<b>2</b>) [the spin Hamiltonian being defined as <i>Ĥ</i> = −<i>J</i>Σ_{<i>i</i> = 1}^<i>n</i>–1<i>Ŝ</i>_<i>i</i><i>Ŝ</i>_<i>i</i>+1]

Ferromagnetic Coupling between Low- and High-Spin Iron(III) Ions in the Tetranuclear Complex <i>f</i><i>ac</i>-{[Fe^III{HB(pz)₃}(CN)₂(μ-CN)]₃Fe^III(H₂O)₃}· 6H₂O ([HB(pz)₃]^- = Hydrotris(1-pyrazolyl)borate)

The novel mononuclear PPh4-fac-[FeIII{HB(pz)3}(CN)3]·H2O (1) [PPh4+= tetraphenylphosphonium cation; (HB(pz)3)- = hydrotris(1-pyrazolyl)borate] and tetranuclear fac-{[FeIII{HB(pz)3}(CN)2(μ-CN)]3FeIII(H2O)3}·6H2O (2) have been prepared and characterized by X-ray diffraction analysis. Crystal data for compound 1:  monoclinic, space group P21/c, a = 9.575(3) Å, b = 21.984(4) Å, c = 16.863(3) Å, β = 100.34(2)°, U = 3486(1) Å3, Z = 4. Crystal data for compound 2:  orthorhombic, space group Pnam, a = 14.084(3) Å, b = 14.799(4) Å, c = 25.725(5) Å, U = 5362(2) Å3, Z = 4. Compound 1 is a low-spin iron(III) compound with three cyanide ligands in fac arrangement and a tridentate pyrazolylborate ligand building a distorted octahedral environment around the iron atom. Compound 2 is the first example of a molecular species containing three peripheral low-spin iron(III) ions linked to a central high-spin iron(III) cation by single cyanide bridges, the anion of 1 acting as a monodentate ligand in 2. Variable-temperature magnetic susceptibility measurements of 2 reveal the occurrence of a significant ferromagnetic coupling between the three peripheral low-spin iron(III) centers and the central high-spin iron(III) ion cations leading to a low-lying nonet spin state

Slow Relaxation of the Magnetization in a 4,2-Wavelike Fe^III₂Co^II Heterobimetallic Chain

The reaction of the low-spin iron­(III) complex [Fe­(dmbpy)­(CN)₄]⁻ (<b>1</b>) with fully solvated cobalt­(II) ions affords the cyanide-bridged heterobimetallic chain {[Fe^III(dmbpy)­(CN)₄]₂Co^II(H₂O)₂}<i>_n</i> · 4<i>n</i>H₂O (<b>2</b>), which exhibits intrachain ferromagnetic coupling and double slow relaxation of the magnetization