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Reactions of nitric acid solutions of bismuth with alkalis have been studied. The effect caused by coprecipitation conditions in the presence of additional agents (EG, PEG 400, or PEG 8000) and without on the phase composition and morphology of α- and γ-Bi2O3 has been determined.

A process for the growth of VSe2 and VTe2 single crystals using VCl3 as a transport agent is proposed and experimentally demonstrated. X-ray diffractometry and Laue X-ray photography results indicate that the crystals thus grown are identical in properties to chalcogenide crystals grown using I2 as a transport agent. The mechanism of chemical vapor transport is discussed and the process conditions are optimized.

In this work, Bi1-xPrxGeSbO6 (x = 0–0.5) solid solutions were synthesized, and the corresponding properties were compared to those of La1-xPrxGa0.5Sb1·5O6. The lattice parameters of the La1-xPrxGa0.5Sb1·5O6 solid solutions decrease linearly as the activator concentration increases. This linear reduction is only observed for the a parameter for Bi1-xPrxGeSbO6. Parameter c shows non-linear growth, which is related to the structural features of BiGeSbO6. Increasing the activator content leads to a decrease in the particle size, which is 0.5–8 μm for Bi1-xPrxGeSbO6. The influence of the host composition on the spectral-luminescent properties of the solid solutions was determined. The difference in the phonon frequencies of BiGeSbO6 and LaGa0.5Sb1·5O6 leads to different luminescence quenching processes for Pr3+ ions. Interactions between Pr3+ ions and Bi3+ were observed for Bi1-xPrxGeSbO6 solid solutions. These processes give rise to changes in the ratios of the luminescence bands of these ions. All the bismuth-containing solid solutions are characterized by the appearance of an additional band in the spectrum related to the luminescence of the bismuth centres of the BiGeSbO6 host. An evaluation of the colour coordinates (CIE 1931) of the Bi1-xPrxGeSbO6 luminescence showed that the colour of the radiation depends on the praseodymium content: as the praseodymium content increases, the luminescence changes from orange (x = 0.005, 0.01) to yellow-green (x = 0.05–0.5). Broadband thermal emission is observed for Bi0.5Pr0.5GeSbO6 under laser excitation with λ = 457 nm and a power density of J = 6 kW/cm2.

The region of pyrochlore existence in the Bi-Mn-Sb-O system, Mn valence state and magnetic properties of pyrochlore compounds have been studied. It is shown that a pyrochlore phase exists in the vide range х = 0.2–0.8 along the Bi(2−x)Mn(1+x/2)Sb(1+x/2)O7 section. Rietveld structure refinement, XANES and EXAFS data show that Bi-Mn-Sb-O pyrochlores are structurally disordered and manganese is in Mn2+/Mn3+mixed-valence state. Mn2+ ions occupy a part of eight coordinated Bi sites while Mn3+ ions are in strongly distorted octahedra. Magnetic measurements confirm the structural data and reveal strong dependence of magnetic properties on Mn concentration. According to dc and ac susceptibility data all studied pyrochlores demonstrate a transition to the conventional spin glass state at Tf ≤ 7 K. The transition temperature decreases with the decrease of Mn3+ amount in the pyrochlore octahedral sublattice. It was also revealed that there exists a threshold Mn concentration above which we detected an antiferromagnetic transition at TN = 42 K along with an SG transition.

A technique has been developed for fluorinating the pyrochlore oxide Bi1.8Fe0.2FeSbO7, and a compound with the composition Bi1.8Fe1.2SbO7–x/2Fx has been obtained. The synthesized oxyfluoride also has the pyrochlore structure (sp. gr. Fd3m), with a lattice parameter a = 10.4443(1) A (R wp = 5.2). It has been shown that the charge balance upon fluorine substitution for oxygen is maintained not through partial reduction of Fe3+ to Fe2+ but through the incorporation of fluorine into oxygen vacancies. The magnetic behavior of the fluorinated pyrochlore phase is determined by the persisting frustration of the octahedral sublattice, which is responsible for the development of a spin glass state below T f = 12 K. The fluorination-induced changes in the anion sublattice led to an increase in the antiferromagnetic exchange interaction between neighboring Fe3+ ions and changes in the dynamic properties of the spin glass phase.

Optical and vibrational spectra of Bi1.8Fe1.2(1 – x)Ga1.2x SbO7 solid solutions with pyrochlore structure have been studied. It has been shown that the compounds have strongly disordered structure. It has been established that a decrease in iron content causes a marked shift of Bi1.8Fe1.2(1 – x)Ga1.2x SbO7 absorption edge. According to assessment of band gap width, Bi1.8Ga1.2SbO7 is the most wide-band compound (2.90 eV), while Bi1.8Fe1.2SbO7 is the most narrow-band compound (1.88 eV).

A series of Bi1.8Fe1.2(1−x)M1.2xSbO7 (M = Ga, Al) compositions with substitution of Fe3+ for diamagnetic Ga3+ and Al3+ has been synthesized and characterized by XRD, Mossbauer spectroscopy and magnetic measurements. X-ray diffraction analysis indicate that the Bi1.8Fe1.2(1−x)Ga1.2xSbO7 (x = 0–1) at the whole x range and Bi1.8Fe0.84Al0.36SbO7 (x = 0.3) are solid solutions of pyrochlore structure. With an increase of Ga3+ content the substitution of Fe3+ for Ga3+ occurs disproportionally over A- and B-sites while Al3+ ion incorporates entirely on B-site. Magnetic measurements showed that all studied compositions fall into the category of disordered, magnetically frustrated materials and at T ≤ 13 K undergo spin-glass transition. The spin-glass phases have a striking sensitivity to substitution of Fe3+ for Ga3+ or Al3+. The comparison of the magnetic behavior of Ga- and Al-containing pyrochlores revealed that, most likely, freezing temperature is governed by Fe3+ ions residing especially on octahedral B-sites.

The article is devoted to the participation of the outstanding dental hygienist F. F. Erisman in the development of the Moscow low territorial sanitary organization. Under his leadership, there was carried out a large-scale study of the impact of conditions of the work and life on the health of plant workers, served as a model for similar types of sanitary-statistical research in a number of rural provinces. F. F. Erisman actively participated in the work of the sanitary organization of the Moscow gubernia Zemstvo, the creation of the first district sanitary Bureau.

The article discusses the government's policy towards the Zemstvo self-government bodies, the influence of increased administrative and political oversight on the establishment and development of Zemstvo medicine, the achievements of the zemstvo doctors in the struggle for public, qualified assistance to the population despite the government policy of limiting the independence of Zemstvo institutions.

World's first biography of Tarasov D.K. (1792-1866), honorary surgeon in ordinary to the king, prominent figure in Russian military medicine. Since 1820 he had accompanied the Emperor Alexander I on trips across Russia and abroad, and had been present at his death. In 1827-1836 he was a civilian-general headquarters doctor. As a director of the Medical Department of the Military Ministry (1836-1846), carried out a number of important reforms to streamline the medical service in the Russian army. He was one of the founders (1833) and long-term president of the Society of Russian Phmirians in St. Petersburg.

The article presents facts of mass arests of physicians by the organs of the All-Russian Special Commission for Combating Counter-revolution and Sabotage during years of the Civil war in Russia in conditions of large-scale epidemics and acute lacking of medical personnel. The article demonstrates the straggle for liberation of physicians led by the RSFSR Narkomzdrav under the direct leadership of N. A. Semashko.

New complex Cr-containing pyrochlores Ln2CrTaO7, Ln = Y, Sm, Gd, were synthesized. The Rietveld refinement of the Ln2CrTaO7 composition confirmed the pyrochlore type of the structure. The Cr3+ oxidation state is corroborated by XANES spectra. The detailed study of DC and AC magnetization of Ln2CrTaO7, Ln = Y, Sm, Gd, was carried out in the temperature range 2–300 K and magnetic field up to 5 T. FM phase transitions at 143, 192, and 163 K were observed in pyrochlores with Y, Sm, and Gd, respectively. It is shown that these transitions are due to canted antiferromagnetism or weak-ferromagnetism in the Ln2CrTaO7 pyrochlores. AFM interactions between Ln- and Cr-sublattices in Sm2CrTaO7 and Gd2CrTaO7 causes AFM transition at T = 42 K, after which magnetization continues increasing. Unusual magnetic properties were observed for Gd2CrTaO7 at low temperatures. Competitive FM and AFM interactions in Cr-and Gd-sublattice give rise to the occurrence of reentrant spin glass at T

The Bi–La–Fe–Sb–O, Pr–Fe–Sb–O, and Bi–Pr–Fe–Sb–O systems have been shown to contain pyrochlore solid solutions. We have determined the limits of the Pr2–xFe1 + xSbO7 and Bi2–xLnxFeSbO7 (Ln = La, Pr) solid solutions and shown that there is no compound corresponding to the “ideal” composition Pr2FeSbO7. Analysis of the magnetic properties of the synthesized compounds indicates that rare earth substitution for bismuth ions has no effect on the spin glass transition and that the spin glass state is only determined by the interaction between the Fe3+ spins on the octahedral site. The Pr3+ paramagnetic ion in Pr2–xFe1 + xSbO7 does not participate in the formation of the spin glass state but makes a paramagnetic contribution to the total magnetic susceptibility, which is especially significant at low temperatures.

Phase equilibria in the La 2 O 3 -Fe 2 O 3 –Sb 2 O 5 system have been studied. The isothermal section was constructed at T=900 °С. The existence of the ternary oxide LaFe 0.5 Sb 1.5 O 6 was confirmed. The structure of this compound was solved using Rietveld refinement of synchrotron radiation-based powder XRD data. LaFe 0.5 Sb 1.5 O 6 crystallizes in a trigonal layered structure relating to PbSb 2 O 6 type (space group P-31m, a=b=5.2446(3) A, c=5.1930(3) A, Z=1). The fine powder of LaFe 0.5 Sb 1.5 O 6 was prepared by molten salt synthesis. The compound was characterized by diffuse reflection and Mossbauer spectroscopy, magnetic measurements, scanning electron microscopy and photocatalytic tests. The magnetic behavior of LaFe 0.5 Sb 1.5 O 6 in the applied magnetic field H=5000 Oe is entirely paramagnetic. By contrast, in the small magnetic field H=100 Oe the magnetic data of LaFe 0.5 Sb 1.5 O 6 indicates an unusual critical behavior near phase transition at T

The crystallization mechanism of chlorine-containing fluorohafnate glasses with the compositions (65–56)HfF4 · (20–x)BaF2 · xBaCl2 · 4LaF3 · (3–y)AlF3 · yInF3 · (5–18)NaF has been studied by X-ray diffraction and differential thermal analysis. The results demonstrate that characteristic features of the glasses are a decrease in glass transition temperature and the precipitation of fine-particle crystalline chloride phases at temperatures below the crystallization temperature of their fluoride analogs. We have studied the effect of the Cl/F ratio in the glass batch and the melt cooling rate on the crystallization behavior of the glasses and determined the heat treatment temperature and time for the formation of transparent glassceramic materials. The luminescence properties of Er3+-doped fluoride and fluorochloride glasses and glassceramics prepared from them have been investigated in the 1.5-µm range.

The thermal behavior of barium and bismuth borate BaBiBO4 is studied by X-ray powder and single-crystal diffraction in a wide temperature range, as well as by the methods of differential scanning calorimetry and dielectric spectroscopy. Thermal expansion is anisotropic, which is caused by the orientation of BO3 boron-oxygen groups. With increasing temperature, the degree of anisotropy of thermal expansion increases up to negative. In the temperature range of 700–800 K, an anomaly of the dielectric properties is observed, accompanied by the change of the temperature dependence of the coefficients of thermal expansion and the heat capacity.

Crystallization processes in the Bi2O3-Fe2O3-NaOH system upon microwave-assisted hydrothermal synthesis have been studied to reveal the effect of the mineralizer concentration, temperature, degree of filling of the autoclave, and the preparation of precursors on the phase composition and the morphology of the reaction product. Submicron powders of bismuth ferrite Bi2Fe4O9 have been synthesized.

The article considers the development of preventive direction and implementation of dispensary methodology into health care practice during the first decade after organization of the RSFSR Narkomzdrav. The roles of such leaders of the Soviet health care as N. A. Semashko and Z. P. Soloviev in organizing functioning of dispensaries, including experience of the Moscow health care agencies in the organization of dispensarization are demonstrated.

The article is devoted to 100th anniversary of organization of the Narkomzdrav of the Russian Soviet Federal Socialist Republic. The input of N.A. Semashko, the People's Commissar of Health Care, is presented concerning organization of the state central board of the national medical sanitary business, organization of the Soviet health care system and development of its major principles. The archive sources were involved to through light upon other aspects of activity of N.A. Semashko, including struggle with arrests of physicians during the Civil War, circumstances of his displacement from the position of People's Commissar of Health Care, work as a director of the Institute of health care organization and history of medicine.