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The formation of intermolecular bonds in C60 has been investigated in detail at pressures below 2.2 GPa and up to 750 K. Fullerene samples were heated in a temperature gradient to obtain data on the formation of dimers and low-dimensional polymers along isobars. Intermolecular bonding was analyzed ex situ by Raman scattering, using both intramolecular modes and intermolecular stretching modes. Semi-quantitative reaction maps are given for the formation of dimers and chains. The activation energy for dimer formation decreases by 0.2 meV pm-1 when intermolecular distances decrease and dimer formation is noticeably affected by the rotational state of molecules. Above 400-450 K larger oligomers are formed; below 1.4 GPa most of these are disordered, with small domains of linear chains, but above this the appearance of stretching modes indicates the existence of ordered one-dimensional polymers. At the highest pressures and temperatures two-dimensional polymers are also observed

DiVA -Digitala Vetenskapliga Arkivet

IR spectra, TG analysis and x-ray diffraction showed a solvated structure for the as-grown C 60 microtubes. Through a gentle heat-treatment in vacuum, pure C 60 microtubes with single crystalline fcc structure were obtained after the elimination of solvents. It is suggested that the C 60 microtubes form through self-assembly from several individual C 60 nanorods

Расчет распределения примеси и потоков ее миграции у клиновидного двойника на основании макроскопической дислокационной модели

High pressure Raman, IR and X-ray diffraction (XRD) studies have been carried out on C-70(Fe(C5H5)(2))(2) (hereafter, "C-70(Fc)(2)") sheets. Theoretical calculation is further used to analyze the Electron Localization Function (ELF) and charge transfer in the crystal and thus to understand the transformation of C-70(Fc)(2) under pressure. Our results show that even at room temperature dimeric phase and one dimensional (1D) polymer phase of C-70 molecules can be formed at about 3 and 8 GPa, respectively. The polymerization is found to be reversible Upon decompression and the reversibility is related to the pressure-tuned charge transfer, as well as the overridden steric repulsion of counter ions. According to the layered structure of the intercalated ferrocene molecules formed in the crystal, we suggest that ferrocene acts as not only a spacer to restrict the polymerization of C-70 molecules within a layer, but also as charge reservoir to tune the polymerization process. This supplies a possible way for us to design the polymerization of fullerenes at suitable conditions

Оценка помехоустойчивости метода диагностики роторных узлов машин в зависимости от условий предварительной фильтрации вибрационного сигнала

Произведено сравнение двух способов предварительной фильтрации при оценке технического состояния роторных узлов машин по методу анализа спектра огибающей вибрационного сигнала. Определена помехоустойчивость метода при воздействии широкополосных шумов.ditions of Prefiltration of the Vibration Signal The comparison of the two methods of prefiltration during evaluation of technical condition of the machine rotor units is performed in the paper using the method of the analysis of the spectrum of the vibration waveform envelope. Noise stability of the method under the action of broadband noise is determined

Individual prediction of treatment outcome in patients with temporomandibular disorders. A quality improvement model.

The general aim of this thesis was to create and evaluate a quality improvement model for prediction of treatment outcome in patients diagnosed with Temporomandibular Disorders (TMD) of either Muscle or Mainly TMJ (Temporomandibular Joint) origin, treated with interocclusal appliances and/or occlusal adjustment. The model was assumed to generate negative predictors of treatment outcome through evaluating all patients predicted Good reaching an objective treatment goal but not having an improvement of 50% or more. The model was created and evaluated by one TMD specialist. The questions were (I) was it possible for the TMD specialist to predict treatment outcome individually in patients diagnosed with TMD and, from the results, create a quality improvement model? (II) Was it possible for eight TMD-trained general dental practitioners, under the supervision of the TMD specialist, to treat TMD patients with similar results to the TMD specialist if the TMD specialist had examined, treatment planned, and individually predicted the treatment outcome? (III) Was it possible for the TMD specialist to improve the possibility to predict individual treatment outcome over time? (IV) Was it possible for one TMD-trained general dental practitioner to copy the clinical part of the model and achieve the same results as the TMD specialist, in patients selected by the TMD specialist? Out of 5165 patients subjected to a functional examination of the masticatory system, 3602 were diagnosed with TMD and subgrouped as either Muscle or Mainly TMJ symptoms. The patients were predicted to have a Good, Dubious, or Poor possibility to have an improvement of 50% or more after treatment. Patients predicted Poor were not offered any treatment. A correct prediction of actual treatment outcome Good was defined as an improvement of 50% or more for muscle and/or TMJ symptoms. A total of 2625 patients began treatment at the specialist clinic for TMD and 2128 completed the full course of treatment. The patients were treated with counseling, interocclusal appliances and/or occlusal adjustment. Treatment outcome was evaluated at an objective treatment goal as improvement in percent using a verbal Numeric Rating Scale ranging from 0 to 100. The results suggest that (I) individual treatment outcome can be predicted in patients with TMD treated by one specialist in TMD and a quality improvement model could be created, (II) eight TMD-trained general dental practitioners could, under the supervision of the TMD specialist, treat TMD patients with similar results to the TMD specialist, (III) the TMD specialist could improve the possibility to predict individual treatment outcome over time, and (IV) the clinical part of the model could be copied by one TMD-trained general dental practitioner with similar results to the TMD specialist. In conclusion, the model works in the hand of one TMD specialist and the clinical part for one general dental practitioner, but it needs to be evaluated by other clinics/clinicians before it can be claimed to be generalizable. The model has identified new negative predictors for treatment outcome in patients with TMD. These predictors need to be investigated further in well controlled clinical trials. The created model is a PDSA cycle

Mapping intermolecular bonding in C60

The formation of intermolecular bonds in C60 has been investigated in detail at pressures below 2.2 GPa and up to 750 K. Fullerene samples were heated in a temperature gradient to obtain data on the formation of dimers and low-dimensional polymers along isobars. Intermolecular bonding was analyzed ex situ by Raman scattering, using both intramolecular modes and intermolecular stretching modes. Semi-quantitative reaction maps are given for the formation of dimers and chains. The activation energy for dimer formation decreases by 0.2 meV pm-1 when intermolecular distances decrease and dimer formation is noticeably affected by the rotational state of molecules. Above 400-450 K larger oligomers are formed; below 1.4 GPa most of these are disordered, with small domains of linear chains, but above this the appearance of stretching modes indicates the existence of ordered one-dimensional polymers. At the highest pressures and temperatures two-dimensional polymers are also observed

Detailed mapping of reaction diagrams for metastable phases

A method is presented to map reaction diagrams for metastable phases by treating a rod-shaped sample under high pressure in a known temperature gradient, such that each point on the sample is treated at a unique, known temperature. After quenching to ambient conditions the structural properties of the sample can be studied by spectroscopic or other techniques. The accuracy and resolution in temperature is mainly limited by the uncertainties in the measured temperature distribution during treatment and the uncertainty in position during analysis. The method is tested by re-mapping the polymerization reaction of C60 under high pressure in the range 0.8 – 2 GPa. Preliminary data show surprisingly sharp "reaction boundaries" at certain temperatures, signalling the onset of dimerization and polymerization of the material