| 1. |
|
|
| 2. |
- Reichartzeder, Dominik, et al.
(author)
-
Crystal Chemistry, Optical Spectroscopy and Crystal Field Calculations of Co3TeO6 and Solid Solutions Co3-xZnxTeO6
- 2018
-
In: European Journal of Inorganic Chemistry. - : WILEY-V C H VERLAG GMBH. - 1434-1948 .- 1099-1948 .- 1099-0682. ; :38, s. 4221-4233
-
Journal article (peer-reviewed)abstract
- Solid solutions Co3-xZnxTeO6 (x = 0-3) were prepared both in polycrystalline and single-crystalline form using solid state reactions and chemical vapour transport reactions, respectively. Miscibility between the isotypic end members was established over the complete range (C2/c, Z = 12, a approximate to 14.85, b approximate to 8.83, c approximate to 10.34 angstrom, beta approximate to 93 degrees). Crystal structure determinations, performed on basis of single crystal laboratory X-ray (at 295 K) and synchrotron (at 10 and 100 K) data of Co3TeO6 and selected solid solutions, revealed no structural phase transition and allowed a detailed insight into the Co -> Zn substitution mechanism. The coordination polyhedra of the five crystallographically independent M2+ cations are distorted octahedra (for three cations), one distorted tetrahedron and one distorted square pyramid. With increasing Zn content the polyhedral distortions increase, and the preference of the Zn2+ cation for the tetrahedral coordination becomes distinctive. Optical absorption and diffuse reflectance spectroscopy reveal extraordinary strong crystal field absorption effects, over wide x ranges predominantly governed by Co2+ in the single tetrahedral and one strongly acentric distorted octahedral site. Superposition Model crystal field calculations yield intrinsic and power-law exponent parameters in general agreement with previous data for Co2+. The five cation sites show comparatively high crystal field strengths at generally very low interelectronic repulsion parameters, indicating prominent covalent contribution to Co-O bonding in Co3-xZnxTeO6 solid solutions.
|
|
| 3. |
- Specht, Sara, et al.
(author)
-
Age, period, and cohort effects on trends in outpatient addiction care utilization in the general Berlin population from 2008 to 2016
- 2022
-
In: BMC Public Health. - : Springer Science and Business Media LLC. - 1471-2458. ; 22:1
-
Journal article (peer-reviewed)abstract
- Background: The aim of this study was to decompose independent effects of age, period, and cohort on trends in outpatient addiction care utilization resulting from alcohol (AUD) and illicit substances use disorders (ISUD). Decomposing trends in addiction care utilization into their independent effects by age, period, and cohort may lead to a better understanding of utilization patterns.Methods: Individuals seeking help in Berlin outpatient addiction care facilities between 2008 and 2016 with an age range of 18–81 years for AUD (n = 46,706) and 18–70 years for ISUD (n = 51,113) were standardized to the general Berlin population using data from the German Federal Statistical Office. Classification of utilization as AUD- (F10) or ISUD-related (F11, F12, F14, F15, F16, F18, F19) help-seeking was based on primary diagnoses according to the International Statistical Classification of Diseases and Related Health Problems. Age was measured in years and period as year of data collection. Cohort was defined as the mathematical difference between period and age. Age, period, and cohort analyses were conducted using the intrinsic estimator model on AUD- and ISUD-related outpatient addiction care utilization.Results: Age effects on AUD-related utilization were highest in 18- to 19-year-old and in 39- to 59-year-old individuals. ISUD-related utilization declined almost continuously with increasing age. Period effects on AUD- and ISUD-related utilization were small. AUD-related utilization was highest in cohorts born from 1951 to 1986. ISUD-related utilization increased in cohorts born between 1954 and 1973 where utilization peaked, followed by a decline of the same order.Conclusions: Age and cohort effects were the strongest drivers of trends in AUD- and ISUD-related outpatient addiction care utilization. Onset of help-seeking in earlier phases of AUD development should be enhanced as well as help-seeking for AUD and ISUD in general. The highest cohort-related rates in the baby boomer and following cohorts for AUD and ISUD underline an increased demand for addiction care.
|
|
| 4. |
- Weil, Matthias, et al.
(author)
-
CoTeO4 : a wide-bandgap material adopting the dirutile structure type
- 2024
-
In: Materials Advances. - : Royal Society of Chemistry. - 2633-5409. ; 5:7, s. 3001-3013
-
Journal article (peer-reviewed)abstract
- High-quality crystals of CoTeO4 were grown by application of chemical vapor transport reactions in closed silica ampoules, starting from polycrystalline material in a temperature gradient 640 °C → 580 °C with TeCl4 as transport agent. Crystal structure analysis of CoTeO4 from single crystal X-ray data revealed a dirutile-type structure with CoII and TeVI atoms at crystallographically distinct sites, each with point group symmetry . The statistical significance and accuracy of the previously reported structural model based on powder data with the ordered arrangement of Co and Te cations was noticeably improved. CoTeO4 does not undergo a structural phase transition upon heating, but decomposes stepwise (Co2Te3O8 as intermediate phase) to Co3TeO6 as the only crystalline phase stable above 770 °C. Temperature-dependent magnetic susceptibility and dielectric measurements suggest antiferromagnetic ordering at ∼50 K. Optical absorption spectroscopy and computational studies reveal wide-band semiconductive behavior for CoTeO4. The experimentally determined band gap of ∼2.42 eV is also found for CdS, which is frequently used in photovoltaic systems but is hazardous to the environment. Hence, CoTeO4 might be a possible candidate to replace CdS in this regard.
|
|
| 5. |
- Weil, Matthias, et al.
(author)
-
CoTeO4 - a wide-bandgap material adopting the dirutile structure type
- 2024
-
In: Materials Advances. - 2633-5409. ; 5:7, s. 3001-3013
-
Journal article (peer-reviewed)abstract
- High-quality crystals of CoTeO4 were grown by application of chemical vapor transport reactions in closed silica ampoules, starting from polycrystalline material in a temperature gradient 640°C → 580°C with TeCl4 as transport agent. Crystal structure analysis of CoTeO4 from single crystal X-ray data revealed a dirutile-type structure with CoII and TeVI atoms at crystallographically distinct sites, each with point group symmetry . The statistical significance and accuracy of the previously reported structural model based on powder data with the ordered arrangement of Co and Te cations was noticeably improved. CoTeO4 does not undergo a structural phase transition upon heating, but decomposes stepwise (Co2Te3O8 as intermediate phase) to Co3TeO6 as the only crystalline phase stable above 770°C. Temperature-dependent magnetic susceptibility and dielectric measurements suggest antiferromagnetic ordering at ∼50 K. Optical absorption spectroscopy and computational studies reveal wide-band semiconductive behavior for CoTeO4. The experimentally determined band gap of ∼2.42 eV is also found for CdS, which is frequently used in photovoltaic systems but is hazardous to the environment. Hence, CoTeO4 might be a possible candidate to replace CdS in this regard.
|
|
| 6. |
|
|
