| 1. |
- Chen, Zhe, et al.
(författare)
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Nano-scale characterization of white layer in broached Inconel 718
- 2017
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Ingår i: Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing. - Amsterdam : Elsevier BV. - 0921-5093 .- 1873-4936. ; 684, s. 373-384
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Tidskriftsartikel (refereegranskat)abstract
- The formation mechanism of white layers during broaching and their mechanical properties are not well investigated and understood to date. In the present study, multiple advanced characterization techniques with nano-scale resolution, including transmission electron microscopy (TEM), transmission Kikuchi diffraction (TKD), atom probe tomography (APT) as well as nano-indentation, have been used to systematically examine the microstructural evolution and corresponding mechanical properties of a surface white layer formed when broaching the nickel-based superalloy Inconel 718.TEM observations showed that the broached white layer consists of nano-sized grains, mostly in the range of 20–50 nm. The crystallographic texture detected by TKD further revealed that the refined microstructure is primarily caused by strong shear deformation. Co-located Al-rich and Nb-rich fine clusters have been identified by APT, which are most likely to be γ′ and γ′′ clusters in a form of co-precipitates, where the clusters showed elongated and aligned appearance associated with the severe shearing history. The microstructural characteristics and crystallography of the broached white layer suggest that it was essentially formed by adiabatic shear localization in which the dominant metallurgical process is rotational dynamic recrystallization based on mechanically-driven subgrain rotations. The grain refinement within the white layer led to an increase of the surface nano-hardness by 14% and a reduction in elastic modulus by nearly 10% compared to that of the bulk material. This is primarily due to the greatly increased volume fraction of grain boundaries, when the grain size was reduced down to the nanoscale.
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| 2. |
- Engvall, Monica, 1940, et al.
(författare)
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Oral health in children and adolescents with myotonic dystrophy.
- 2007
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Ingår i: European journal of oral sciences. - : Wiley. - 0909-8836 .- 1600-0722. ; 115:3, s. 192-7
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Tidskriftsartikel (refereegranskat)abstract
- Myotonic dystrophy or dystrophia myotonica (DM) is a hereditary neuromuscular multisystem disease with a varying clinical expressivity and severity. The objective of this study was to assess the oral health in children with myotonic dystrophy and to compare it with a control group. Fifty-six DM patients, aged 2.7-18.0 yr, were compared with age- and gender-matched control patients with respect to caries, plaque, and gingivitis. Oral function and signs of temporomandibular dysfunction (TMD) were assessed, and the ability to co-operate in dental treatment was estimated. Questionnaires concerning eating habits, dental care, traumatic injuries to teeth, and orofacial function were also used. The DM patients had significantly more caries, plaque, and gingivitis than did control patients. They had more TMD problems and lower co-operation ability than the healthy control persons. General sedation was frequently needed to carry through dental treatment. DM patients are at risk of caries, gingivitis and TMD problems, and need intensified prophylactic care. Behavior management problems are common.
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| 3. |
- Engvall, Monica, 1940, et al.
(författare)
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Oral health status in a group of children and adolescents with myotonic dystrophy type 1 over a 4-year period.
- 2009
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Ingår i: International journal of paediatric dentistry / the British Paedodontic Society [and] the International Association of Dentistry for Children. - 1365-263X. ; 19:6, s. 412-22
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Tidskriftsartikel (refereegranskat)abstract
- AIM: The aim of this longitudinal study was to evaluate changes in oral health, orofacial function, and dental care in children with myotonic dystrophy type 1 (DM1) in comparison with a control group. METHODS: Thirty-six DM1 patients and 33 control patients out of originally 37 in each group were examined on two occasions about 4 years apart. Caries, plaque, and gingivitis were registered, mouth opening capacity assessed and the ability to cooperate in dental treatment estimated. Questionnaires concerning different aspects of oral health and care, symptoms of temporomandibular dysfunction (TMD), and dental trauma were also used. RESULTS: The DM1-patients, in particular the boys, had significantly more caries, plaque, and gingivitis than the control patients on both occasions and the increase in decayed missing or filled permanent teeth (DMFT) and surfaces (DMFS) was significantly larger. They received more dental care and had lower cooperation ability. Mouth opening capacity and increase of it was significantly lower and symptoms of TMD were significantly more frequent. CONCLUSIONS: DM1 patients, as they grow older, have increasing amounts of plaque and risk of caries and gingivitis. They have more TMD problems. Behaviour management problems do not seem to decrease with age. Increased prophylactic care is essential for DM1 patients.
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| 4. |
- Karlsson, Maths, 1978, et al.
(författare)
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Using Neutron Spin-Echo To Investigate Proton Dynamics in Proton-Conducting Perovskites
- 2010
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Ingår i: Chemistry of Materials. - : American Chemical Society (ACS). - 1520-5002 .- 0897-4756. ; 22:3, s. 740-742
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Tidskriftsartikel (refereegranskat)abstract
- The applicability and potential of neutron spin-echo (NSE) to study proton dynamics in proton-conducting ceramics was studied. The experiment was performed on hydrated BaZr 0,90 Y 0.10 O 2.95 (10Y:BZO), a cubic perovskite with a relatively high proton conductivity. The NSE experiment was performed at the IN15 spectrometer at Institut Laue-Langevin (ILL) in Grenoble, France. The relaxation rate for two Q-values for the temperature 563 K was determined. The first-principles calculations were carried out within the framework of density functional theory (DFT). The calculated diffusion harriers far from Y-dopants are found to he 0.20 and 0.18 eV for the proton transfer and hydroxyl rotation motion, respectively. The binding energy to a Y-dopant is 0.16 eV, and the influence of the Y-dopant on the energetics for the proton is quite extended in space, including both the first and the second coordination shells.
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| 5. |
- Karlsson, Maths, 1978, et al.
(författare)
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Vibrational Properties of Protons in Hydrated BaInxZr1-xO3-x/2
- 2005
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Ingår i: Physical Review B - Condensed Matter and Materials Physics. - 2469-9950 .- 2469-9969. ; 72, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the local proton dynamics in the proton conducting hydrated perovskite system BaInxZr1-xO3-x/2 (x=0.25-0.75) using infrared spectroscopy and first-principles calculations. We show that oxygen vacancies and dopant atoms in the vicinity of the proton tilt the proton toward a neighboring oxygen creating strongly hydrogen-bonded configurations. This is manifested as a strong redshift of the O-H stretch band in the infrared absorption spectrum. We also find considerable fluctuations of the nearest and next-nearest oxygen-proton distances with time, resulting in additional spectral broadening. By comparing the frequencies of computed O-H stretch modes we can relate specific local configurations to different parts of the broad O-H stretch band. Even though hydrogen-bonded configurations favor proton transfer they hinder the long-range migration by decreasing the reorientational rate. Thus, in order to optimize the proton mobility it is important to avoid extreme configurations caused by either oxygen vacancies or dopant atoms in the perovskite structure.
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| 6. |
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| 7. |
- Sundell, Kerstin, et al.
(författare)
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Quality of life in adolescents with asthma, during the transition period from child to adult.
- 2011
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Ingår i: Clinical Respiratory Journal. - 1752-6981. ; 5:4, s. 195-202
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Tidskriftsartikel (refereegranskat)abstract
- Aim: The present investigation was designed to evaluate the health-related quality of life (HRQOL) of adolescents with asthma between the age of 16 and 21, when they are transferred from paediatric to adult care. Methods: In this prospective study, 156 teenagers (69 females) with asthma were screened employing spirometry, a histamine challenge, skin prick test for allergy and filled out the 'Living with Asthma Questionnaire' both at the time of entry into the study and after 2 and 5 years of follow-up. An exercise test and questions concerning regular performed exercise were carried out at baseline and 5 years later. Results: At all three time-points, the HRQOL of the men was generally better than that of the women. At the same time, the HRQOL of both genders was significantly better, both in terms of the overall scores (P < 0.001) as well as the scores for most of the individual domains, in connection with the 5-year follow-up. The young women who exercised regularly at the time of their entry exhibited better HRQOL at this time than those who did not (P < 0.001), whereas regular exercise had no impact on the HRQOL of the young men. The women with severe asthma demonstrated a poorer HRQOL than those suffering from mild-to-moderate asthma. Conclusion: The HRQOL of adolescents with asthma improves with age. The pronounced positive correlation between regular exercise and HRQOL in female adolescents with asthma revealed here deserves special attention in the care of young women and deserves further exploration.
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