Eu2Si5N8 and EuYbSi4N7

The crystal structures of dieuropium penta siliconoctanitride, Eu2Si5N8, and europium ytterbium tetrasiliconheptanitride, EuYbSi4N7, are based on three-dimensional networks of corner-sharing SiN4 tetrahedra. Eu2Si5N8 is isotypic with the previously reported Sr and Ba analogues; EuYbSi4N7 is isotypic with SrYbSi4N7 and BaYbSi4N7

High temperature syntheses of novel nitrido- and oxonitrido-silicates and sialons using rf furnaces

The high-temperature reaction of pure metals with silicon diimide Si(NH)2 in a specially developed radiofrequency furnace has been successfully applied to the synthesis of novel highly condensed nitridosilicates. With SrCO3 as an additional starting material this procedure has now been extended to the synthesis of oxonitridosilicates and oxonitridoaluminosilicates (sialons). Two novel sialons SrSiAl2 O3 N2 [space group P21 21 21 (no. 19), a=491.89(6), b=789.73(7), c=1134.94(18) pm, Z=4] and SrErSiAl3 O3 N4 [space group P63 mc (no. 186), a=606.53(3), c=985.90(8) pm, Z=2] have been obtained as coarsely crystalline materials. According to single crystal X-ray diffraction both compounds adopt structure types which are unprecedented for sialons. They derive from the nitridosilicates LnSi3 N5 (Ln=La, Ce, Pr, Nd) and MYbSi4 N7 (M=Sr, Ba, Eu), respectively, by partial substitution of Si by Al and N by O. For SrSiAl2 O3 N2 and SrErSiAl3 O3 N4 an unambiguous crystallographic differentiation between the tetrahedral centres (Al and Si) as well as the bridging atoms of the framework structures (N and O) seems reasonable

On a quantum particle in laser channels

In this paper the effective potential describing interaction of a scalar quantum particle with arbitrary nonuniform laser field is derived for a wide spectrum of the particle energies. The presented method allows to take into account all the features of the effective potential for a scalar particle. The derived expression for effective potential for quantum particle has the same form as the one presented earlier for a classical particle. A special case for channeling of a quantum particle as well as accompanying channeling radiation in a field formed by two crossed plane laser waves is considered. It is shown that relativistic particles moving near the laser channel bottom should be examined as quantum ones at both arbitrarily large longitudinal energies and laser fields of accessible intensities

Разработка процесса аргонодуговой сварки неплавящимся электродом с управлением магнитным дутьем

Объектом исследования является процесс дуговой сварки неплавящимся электродом в защитной среде аргона Цель работы – исследование и разработка технологии сварки неплавящимся электродом в аргоне с управлением собственным магнитным дутьем. В процессе исследования проводились анализ методов повышения эффективности и способы сварки неплавящимся электродом с применением импульсного питания сварочной дуги, проведен анализ сварки модулированным током и предложен наиболее перспективный способ. В результате исследования разработан процесс сварки неплавящимся электродом с управлением магнитным дутьем. Область применения: данный способ сварки может применяться в разных отраслях: нефтяной, газовой, котельной, электрического промышленности, а также в коммунальном, сельском хозяйстве и кораблестроении.The object of investigation is the process of arc welding with a non-consumable electrode in an argon protective medium The purpose of the work is to study and develop the welding technology with a non-consumable electrode in argon with control of its own magnetic blow. In the process of the investigation, methods of increasing efficiency and methods for welding with a non-consumable electrode were analyzed using pulse welding arc welding, an analysis of modulated current welding was performed and the most promising method was proposed. As a result of the research, a process of welding with a non-consumable electrode with control of magnetic blowing was developed. Scope: this method of welding can be used in different industries: oil, gas, boiler, electrical industry, as well as in commun

An organometallic chimie douce approach to new Re(x)W(1-x)O3 phases

Re(x)W(1-x)O3.H2O and Re(x)W(1-x)O3 phases are prepared by a new organometallic chimie douce concept employing the organometallic precursor methyltrioxorhenium.Comment: 3 pages, 6 figures, submitted to Chem. Com

Synthesis of Alkaline Earth Diazenides MAEN2 (MAE = Ca, Sr, Ba) by Controlled Thermal Decomposition of Azides under High Pressure

The alkaline earth diazenides MAEN2 with MAE = Ca, Sr and Ba were synthesized by a novel synthetic approach, namely, a controlled decomposition of the corresponding azides in a multianvil press at highpressure/ high-temperature conditions. The crystal structure of hitherto unknown calcium diazenide (space group I4/mmm (no. 139), a = 3.5747(6) Å, c = 5.9844(9) Å, Z = 2, wRp = 0.078) was solved and refined on the basis of powder X-ray diffraction data as well as that of SrN2 and BaN2. Accordingly, CaN2 is isotypic with SrN2 (space group I4/mmm (no. 139), a = 3.8054(2) Å, c = 6.8961(4) Å, Z = 2, wRp = 0.057) and the corresponding alkaline earth acetylenides (MAEC2) crystallizing in a tetragonally distorted NaCl structure type. In accordance with literature data, BaN2 adopts a more distorted structure in space group C2/c (no. 15) with a = 7.1608(4) Å, b = 4.3776(3) Å, c = 7.2188(4) Å, β = 104.9679(33)°, Z = 4 and wRp = 0.049). The N−N bond lengths of 1.202(4) Å in CaN2 (SrN2 1.239(4) Å, BaN2 1.23(2) Å) correspond well with a double-bonded dinitrogen unit confirming a diazenide ion [N2]2−. Temperature-dependent in situ powder X-ray diffractometry of the three alkaline earth diazenides resulted in formation of the corresponding subnitrides MAE2N (MAE = Ca, Sr, Ba) at higher temperatures. FTIR spectroscopy revealed a band at about 1380 cm−1 assigned to the N−N stretching vibration of the diazenide unit. Electronic structure calculations support the metallic character of alkaline earth diazenides

Exercise as an add-on treatment in individuals with schizophrenia: results from a large multicenter randomized controlled trial

Current treatment methods do not achieve recovery for most individuals with schizophrenia, and symptoms such as negative symptoms and cognitive deficits often persist. Aerobic endurance training has been suggested as a potential add-on treatment targeting both physical and mental health. We performed a large-scale multicenter, rater-blind, parallel-group randomized controlled clinical trial in individuals with stable schizophrenia. Participants underwent a professionally supervised six-month training comprising either aerobic endurance training (AET) or flexibility, strengthening, and balance training (FSBT, control group), follow-up was another six months. The primary endpoint was all-cause discontinuation (ACD); secondary endpoints included effects on psychopathology, cognition, functioning, and cardiovascular risk. In total, 180 participants were randomized. AET was not superior to FSBT in ACD and most secondary outcomes, with dropout rates of 59.55% and 57.14% in the six-month active phase, respectively. However, both groups showed significant improvements in positive, general, and total symptoms, levels of functioning and in cognitive performance. A higher training frequency additionally promoted further memory domains. Participants with higher baseline cognitive abilities were more likely to respond to the interventions. Our results support integrating exercise into schizophrenia treatment, while future studies should aim to develop personalized training recommendations to maximize exercise-induced benefits

Health Care Workers’ Sick Leave due to COVID-19 Vaccination in Context With SARS-CoV-2 Infection and Quarantine—A Multicenter Cross-Sectional Survey

Background Reactogenicity of coronavirus disease 2019 (COVID-19) vaccines can result in inability to work. The object of this study was to evaluate health care workers’ sick leave after COVID-19 vaccination and to compare it with sick leave due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and quarantine leave. Methods A multicenter cross-sectional survey was conducted at Regensburg University Medical Center and 10 teaching hospitals in South-East Germany from July 28 to October 15, 2021. Results Of 2662 participants, 2309 (91.8%) were fully vaccinated without a history of SARS-CoV-2 infection. Sick leave after first/second vaccination occurred in 239 (10.4%) and 539 (23.3%) participants. In multivariable logistic regression, the adjusted odds ratio for sick leave after first/second vaccination compared with BNT162b2 was 2.26/3.72 for mRNA-1237 (95% CI, 1.28–4.01/1.99–6.96) and 27.82/0.48 for ChAdOx1-S (95% CI, 19.12–40.48/0.24–0.96). The actual median sick leave (interquartile range [IQR]) was 1 (0–2) day after any vaccination. Two hundred fifty-one participants (9.4%) reported a history of SARS-CoV-2 infection (median sick leave [IQR] 14 [10–21] days), 353 (13.3%) were quarantined at least once (median quarantine leave [IQR], 14 [10–14] days). Sick leave due to SARS-CoV-2 infection (4642 days) and quarantine leave (4710 days) accounted for 7.7 times more loss of workforce than actual sick leave after first and second vaccination (1216 days) in all fully vaccinated participants. Conclusions Sick leave after COVID-19 vaccination is frequent and is associated with the vaccine applied. COVID-19 vaccination should reduce the much higher proportion of loss of workforce due to SARS-CoV-2 infection and quarantine

Li14Ln5[Si11N19O5]O2F2 with Ln = Ce, Nd-Representatives of a Family of Potential Lithium Ion Conductors

The isotypic layered oxonitridosilicates Li14Ln5[Si11N19O5]O2F2 (Ln = Ce, Nd) have been synthesized using Li as fluxing agent and crystallize in the orthorhombic space group Pmmn (Z = 2, Li14Ce5[Si11N19O5]O2F2: a = 17.178(3), b = 7.6500(15), c = 10.116(2) Å, R1 = 0.0409, wR2 = 0.0896; Li14Nd5 Si11N19O5]O2F2: a = 17.126(2), b = 7.6155 15), c = 10.123(2) Å, R1 = 0.0419, wR2 = 0.0929). The silicate layers consist of dreier and sechser rings interconnected via common corners, yielding an unprecedented silicate substructure. A topostructural analysis indicates possible 1D ion migration pathways between five crystallographic independent Li positions. The specific Li-ionic conductivity and its temperature dependence were determined by impedance spectroscopy as well as DC polarization/depolarization measurements. The ionic conductivity is on the order of 5 × 10−5 S/cm at 300°C, while the activation energy is 0.69 eV. Further adjustments of the defect chemistry (e.g., through doping)can make these compounds interesting candidates for novel oxonitridosilicate based ion conductors