2,794 research outputs found

    CW and pulsed electrically detected magnetic resonance spectroscopy at 263 GHz/12 T on operating amorphous silicon solar cells

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    Here we describe a new high frequency/high field continuous wave and pulsed electrically detected magnetic resonance (CW EDMR and pEDMR) setup, operating at 263 GHz and resonance fields between 0 and 12 T. Spin dependent transport in illuminated hydrogenated amorphous silicon p-i-n solar cells at 5 K and 90 K was studied by in operando 263 GHz CW and pEDMR alongside with complementary X-band CW EDMR. Benefiting from the superior resolution at 263 GHz, we were able to better resolve EDMR signals originating from spin dependent hopping and recombination processes. 5 K EDMR spectra were found to be dominated by conduction and valence band tale states involved in spin dependent hopping, with additional contributions from triplet exciton states. 90 K EDMR spectra could be assigned to spin pair recombination involving conduction band tail states and dangling bonds as dominating spin dependent transport process, with additional contributions from valence band tail and triplet exciton states.Comment: 8 pages, 4 figure

    Transport and recombination through weakly coupled localized spin pairs in semiconductors during coherent spin excitation

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    Semi-analytical predictions for the transients of spin-dependent transport and recombination rates through localized states in semiconductors during coherent electron spin excitation are made for the case of weakly spin-coupled charge carrier ensembles. The results show that the on-resonant Rabi frequency of electrically or optically detected spin-oscillation doubles abruptly as the strength of the resonant microwave field gamma B_1 exceeds the Larmor frequency separation within the pair of charge carrier states between which the transport or recombination transition takes place. For the case of a Larmor frequency separation of the order of gamma B_1 and arbitrary excitation frequencies, the charge carrier pairs exhibit four different nutation frequencies. From the calculations, a simple set of equations for the prediction of these frequencies is derived

    Methodological challenges in following up patients of a hospital child protection team: is there a recruitment bias?

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    BACKGROUND: The aims of this study are to describe the methodological challenges in recruiting a follow-up sample of children referred to an interdisciplinary hospital child protection team (CPT) and to compare participating versus non-participating groups on several demographic variables and maltreatment characteristics. METHODS: Of the 319 in- and outpatients referred to the CPT at University Children's Hospital Zurich from 2005-2006 a sample of 180 children was drawn to contact for a follow-up. The children and their parents were asked to participate in a face-to-face interview at the hospital; in 42 cases the children and parents consented to do so. Alternatively, the parents could take part in a telephone interview (n = 39). Non-participation resulted because no contact or adequate communication in German, French, or English could be established (n = 49) or because the parents or children refused to participate (n = 50). RESULTS: Participants and non-participants did not differ significantly in mean child age at follow-up, gender, family status, place of residence, certainty and type of maltreatment, and type of perpetrator. However, the child's nationality had a significant impact: Percentages of foreign nationals were higher in the fully participating group (45%; n = 19) and the non-contactable group (53%; n = 26) and significantly lower in the refusal (26%; n = 10) and the telephone interview group (18%; n = 9). Although a high percentage of families had moved in the few years since the CPT intervention (32%; n = 57), the percentage of moves was not significantly higher in non-participants compared to participants. CONCLUSIONS: Further research is needed to support these results in different national backgrounds and to test for biases in variables not included - especially socioeconomic status. This includes gathering more detailed information on non-participants, while respecting ethical boundaries. Overall, the fact that only child's nationality was unevenly distributed between participants and non-participants is encouraging

    Стадії укладення договору лізингу

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    Узагальнено вітчизняний та зарубіжний досвід укладання лізингових угод. Здійснено структуризацію стадій лізингового процесу. Ключові слова: лізингова угода, лізингодавець, лізингоодержувач.Обобщен отечественный и зарубежный опыт заключения лизинговых соглашений. Осуществлена структуризация стадий лизингового процесса. Ключевые слова: лизинговое соглашение, лизингодатель, лизингополучатель.The generalization of the domestic and international experience in the concluding of leasing agreements is aimed in this article. The consecutive examination of the stages of leasing process is set up structurally. Key words: lease contract, leasee, leasor

    О плазменно-вибрационном воздействии на железорудный массив в условиях термического котлообразования

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    Розглянуті процеси об’ємної іонізації в кварцитах, які виникають при плазмово-віброударній дії на мінерали. Показано, що плазмово віброударне навантаження матеріалів приводить до виникнення локальних областей з аномальним ефектом Шоттки.The process of volume ionization in the quartzite, that arose at plasma-vibrostriking action upon minerals, was considered. It was shown, that the plasma-vibrostriking loading of materials resulted in the appearance of local regions with an anomalous Shottci effect

    Investigations on nucleophilic layers made with a novel plasma jet technique

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    In this work a novel plasma jet technique is used for the deposition of nucleophilic films based on (3-aminopropyl)trimethoxysilane at atmospheric pressure. Film deposition was varied with regard to duty cycles and working distance. Spectral ellipsometry and chemical derivatization with 4-(trifluoromethyl)benzaldehyde using ATR- FTIR spectroscopy measurements were used to characterize the films. It was found that the layer thickness and the film composition are mainly influenced by the duty cycle

    Active vitamin D (1,25-dihydroxyvitamin D) and bone health in middle-aged and elderly men: the European male aging study (EMAS)

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    <p>Context: There is little information on the potential impact of serum 1,25-dihydroxyvitamin D [1,25(OH)2D] on bone health including turnover.</p> <p>Objective: The objective of the study was to determine the influence of 1,25(OH)2D and 25-hydroxyvitamin D [25(OH)D] on bone health in middle-aged and older European men.</p> <p>Design, Setting, and Participants: Men aged 40–79 years were recruited from population registers in 8 European centers. Subjects completed questionnaires that included questions concerning lifestyle and were invited to attend for quantitative ultrasound (QUS) of the heel, assessment of height and weight, and a fasting blood sample from which 1,25(OH)2D, 25(OH)D, and PTH were measured. 1,25(OH)2D was measured using liquid chromatography tandem mass spectrometry. Bone markers serum N-terminal propeptide of type 1 procollagen (P1NP) and crosslinks (β-cTX) were also measured. Dual-energy x-ray absorptiometry (DXA) of the hip and lumbar spine was performed in 2 centers.</p> <p>Main Outcome Measure(s): QUS of the heel, bone markers P1NP and β-cTX, and DXA of the hip and lumbar spine were measured.</p> <p>Results: A total of 2783 men, mean age 60.0 years (SD 11.0) were included in the analysis. After adjustment for age and center, 1,25(OH)2D was positively associated with 25(OH)D but not with PTH. 25(OH)D was negatively associated with PTH. After adjustment for age, center, height, weight, lifestyle factors, and season, 1,25(OH)2D was associated negatively with QUS and DXA parameters and associated positively with β-cTX. 1,25(OH)2D was not correlated with P1NP. 25(OH)D was positively associated with the QUS and DXA parameters but not related to either bone turnover marker. Subjects with both high 1,25(OH)2D (upper tertile) and low 25(OH)D (lower tertile) had the lowest QUS and DXA parameters and the highest β-cTX levels.</p> <p>Conclusions: Serum 1,25(OH)2D is associated with higher bone turnover and poorer bone health despite being positively related to 25(OH)D. A combination of high 1,25(OH)2D and low 25(OH)D is associated with the poorest bone health.</p&gt
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