Scintillation neutron detector on the basis of boron-containing plastics

Main parameters are presented for plastic scintillators containing boron. These scintillators were obtained by the block polymerization method of polystyrene with luminescent dopants and allyldodecaborane. Sample dimensions: diameter 25 mm, height 25 mm. Parameters studied included light output, sensitivity to neutrons and time characteristics.У роботі представлені основні параметри пластмасових сцинтиляторів, які містять бор. Ці сцинтилятори одержані за допомогою методу блочної полімеризації полістиролу з домішками, що випромінюють люмінесценцію та алилдодекабораном. Розміри зразків: Ø25х25 мм. Досліджені світловий вихід, чутливість до нейтронів та компоненти висвічування.В работе представлены основные параметры пластмассовых сцинтилляторов, содержащих бор. Эти сцинтилляторы получены методом блочной полимеризации полистирола с люминесцирующими добавками и аллилдодекабораном. Размеры образцов: диаметр 25 мм и высота 25 мм. Исследованы световой выход, чувствительность к нейтронам и времен- ные характеристики

Molecular and crystal structures of 11-phenyl-4,9,10,11-tetrahydro-1,2,4-triazolo[5,1-b]naphtho[1,2-d]pyrimidine: The nature of disorder in the dihydronaphthalene fragment

The crystal structure of 11-phenyl-4,9,10,11-tetrahydro-1,2,4-triazolo[5,1-b]naphtho[1,2-d]pyrimidine has been studied by X-ray diffraction analysis at 293 and 153 K. The crystal data are as follows. At T = 293 K: monoclinic, a = 10.588(3), b = 18.196(6), and c = 7.939(2) Å; β = 98.55(1)°; sp. gr. P21/c; Z = 4; number of reflections = 1780; wR2 = 0.139; and R1 = 0.067 for 1130 reflections with F > 4σ(F). At T = 153 K: monoclinic, a = 10.414(9), b = 18.11(2), and c = 7.952(6) Å; β = 97.95(2)°; sp. gr. P21/c; Z = 4; number of reflections = 2384; wR2 = 0.161; and R1 = 0.078 for 1456 reflections with F > 4σ(F). It is demonstrated that annelation of the dihydropyrimidine cycle with a carbocycle at the C=C double bond brings about a substantial flattening of the boat conformation of the dihydroheterocycle. The dihydronaphthalene fragment is disordered between two equally probable conformations. The presence of the forbidden intermolecular contact C⋯C (2.83 Å) indicates that the disorder is statistic in nature, which is corroborated by the low-temperature (T = 153 K) investigation. In the crystal, the molecules are linked by hydrogen bonds that give rise to the centrosymmetric dimers that, in turn, form the ribbons. Each ribbon contains molecules in which the dihydronaphthalene fragments adopt only one of two conformations found

Molecular and crystal structures of 11-phenyl-4,9,10,11-tetrahydro-1,2,4-triazolo[5,1-b]naphtho[1,2-d]pyrimidine: The nature of disorder in the dihydronaphthalene fragment

The crystal structure of 11-phenyl-4,9,10,11-tetrahydro-1,2,4-triazolo[5,1-b]naphtho[1,2-d]pyrimidine has been studied by X-ray diffraction analysis at 293 and 153 K. The crystal data are as follows. At T = 293 K: monoclinic, a = 10.588(3), b = 18.196(6), and c = 7.939(2) Å; β = 98.55(1)°; sp. gr. P21/c; Z = 4; number of reflections = 1780; wR2 = 0.139; and R1 = 0.067 for 1130 reflections with F > 4σ(F). At T = 153 K: monoclinic, a = 10.414(9), b = 18.11(2), and c = 7.952(6) Å; β = 97.95(2)°; sp. gr. P21/c; Z = 4; number of reflections = 2384; wR2 = 0.161; and R1 = 0.078 for 1456 reflections with F > 4σ(F). It is demonstrated that annelation of the dihydropyrimidine cycle with a carbocycle at the C=C double bond brings about a substantial flattening of the boat conformation of the dihydroheterocycle. The dihydronaphthalene fragment is disordered between two equally probable conformations. The presence of the forbidden intermolecular contact C⋯C (2.83 Å) indicates that the disorder is statistic in nature, which is corroborated by the low-temperature (T = 153 K) investigation. In the crystal, the molecules are linked by hydrogen bonds that give rise to the centrosymmetric dimers that, in turn, form the ribbons. Each ribbon contains molecules in which the dihydronaphthalene fragments adopt only one of two conformations found

Study of Mn²⁺ and MnO₄⁻ products interaction in alkaline solution

Interaction of Mn²⁺ ions with MnO₄⁻ in alkaline medium is considered. The main component of this interaction is manganese oxyhydroxide MnO(OH) and not manganese dioxide, that is revealed by means of X-ray diffraction analysis, IR-spectrometry and chemical analysis. It is demonstrated that decomposition of MnO(OH) occurs in the wide temperature range (60-550 °C), that results in mixture of Mn₂O₃ and MnO₂ oxides formation

Formation characteristics of Fe₃O₄ magnetic particles precipitated from aqueous solutions and their sorption properties

Effect of temperature and iron concentration in solution on the phase composition, particle size, and magnetization was studied. It is shown that amount of the magnetite phase increases with the temperature increase. The magnetization slightly decreases with increase in the initial iron concentration. It is found that, regardless of the deposition conditions, spherical particles are formed, the average size of which varies within 7 to 15 nm. Comparison between the for removal efficiency and sorption capacity of the particles with the magnetite and hematite phase for cobalt was carried out. The sorption capacity of the particles is essentially independent of the phase composition and is about 18 mg/g for cobalt. For preparation of sorption material based on Fe₃O₄ magnetic particles, it is recommended to carry out the precipitation at the temperature of not lower than 80°C and the concentration of iron in solution of 0.15 to 0.3 M. The resulting particles comprise not less than 90 wt. % of magnetite phase and are characterized by magnetization of 65 to 70 A·m²/kg

Doebner-type pyrazolopyridine carboxylic acids in an Ugi four-component reaction

Substituted 1H-pyrazolo[3,4-b]pyridine-4- and 1H-pyrazolo[3,4-b]pyridine-6-carboxamides have been synthetized through a Doebner-Ugi multicomponent reaction sequence in a convergent and versatile manner using diversity generation strategies: combination of two multicomponent reactions and conditions-based divergence strategy. The target products contain as pharmacophores pyrazolopyridine and peptidomimetic moieties with four points of diversity introduced from readily available starting materials including scaffold diversity. A small focused compound library of 23 Ugi products was created and screened for antibacterial activity. © 2019 Murlykina et al