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Framework Materials (framework + material)
Selected AbstractsFlexibility in a Metal,Organic Framework Material Controlled by Weak Dispersion Forces: The Bistability of MIL-53(Al),ANGEWANDTE CHEMIE, Issue 41 2010Dr. Andrew M. Walker Atmungsaktiv: Nach DFT-Rechnungen wird die außergewöhnliche, thermisch induzierte Dichteänderung der Metall-organischen Gerüststruktur MIL53(Al) durch konkurrierende kurz- und langreichweitige Wechselwirkungen sowie entropische Faktoren bestimmt. Wie die gezeigte Struktur andeutet (C grün, Al cyan, O rot, H weiß), stabilisieren bei tiefen Temperaturen dispersive Wechselwirkungen eine engporige Form. Bei 325,375,K verursacht die Schwingungsentropie eine Ausdehnung der Struktur, sodass nun große Mengen leichter Gase adsorbiert werden können. [source] Technetium-99 MAS,NMR Spectroscopy of a Cationic Framework Material that Traps TcO4, Ions,ANGEWANDTE CHEMIE, Issue 34 2010Ping Yu Dr. Kein Entrinnen für Technetium: Nur wenige 99Tc-MAS-NMR-Spektren wurden bisher aufgenommen. Die hier vorgestellten Spektren zeigen, dass durch Kernspaltung gebildete, potenziell umweltgefährdende TcO4, -Ionen aus simulierten radioaktiven Abwässern in den Kanälen und Hohlräumen eines Materials mit kationischem Gerüst eingefangen werden (siehe Bild). [source] Time-Evolving Self-Organization and Autonomous Structural Adaptation of Cobalt(II),Organic Framework Materials with scu and pts NetsCHEMISTRY - A EUROPEAN JOURNAL, Issue 24 2008Jing-Yun Wu Dr. Going where? The spontaneous, dynamic adjustment of equilibrium condition (KI/CoII ratio) is found to be a key factor in switching the assembly direction of CoII and K4btec (btec=benzene-1,2,4,5-tetracarboxylate). Compound 1 with a rare scu net was generated within the first three days. A few days later a new product,compound 2 with a pts net,autonomously formed. [source] Can Metal,Organic Framework Materials Play a Useful Role in Large-Scale Carbon Dioxide Separations?CHEMSUSCHEM CHEMISTRY AND SUSTAINABILITY, ENERGY & MATERIALS, Issue 8 2010Seda Keskin Dr. Abstract Metal,organic frameworks (MOFs) are a fascinating class of crystalline nanoporous materials that can be synthesized with a diverse range of pore dimensions, topologies, and chemical functionality. As with other well-known nanoporous materials, such as activated carbon and zeolites, MOFs have potential uses in a range of chemical separation applications because of the possibility of selective adsorption and diffusion of molecules in their pores. We review the current state of knowledge surrounding the possibility of using MOFs in large-scale carbon dioxide separations. There are reasons to be optimistic that MOFs may make useful contributions to this important problem, but there are several critical issues for which only very limited information is available. By identifying these issues, we provide what we hope is a path forward to definitively answering the question posed in our title. [source] Translucency of glass-fibre-reinforced composite materialsJOURNAL OF ORAL REHABILITATION, Issue 8 2004T. Nakamura summary, The purpose of this study was to examine the translucency of glass-fibre-reinforced composite framework materials. Vectris and FibreKor, as well as an experimental material, were the glass-fibre-reinforced framework materials used. Targis, Sculpture and Estenia were the types of particulate filler composites veneered onto frameworks. Specimens were fabricated from each material, 0·5 and 1·0 mm thick. In addition, laminate specimens, 1·5 mm thick, were fabricated. The translucency of each specimen was evaluated by determining its contrast ratio. The laminate specimens were examined for colour differences. The experimental framework material was more translucent than the enamel composite when it was not coloured, and was nearly as translucent as the dentine composite when coloured. The commercial tooth-coloured framework materials were nearly as translucent as the dentine composite. It was found that it was possible to reproduce the same colour as the veneering dentine composite, when the framework thickness was 0·5 mm, except in the case of FibreKor. Within the limitations of this study, tooth-coloured, glass-fibre-reinforced framework materials are nearly as translucent as the veneering dentine composite, but these materials affect the colour of the prosthesis if the thickness of the framework material is increased beyond a certain point. [source] Load-bearing capacity of all-ceramic three-unit fixed partial dentures with different computer-aided design (CAD)/computer-aided manufacturing (CAM) fabricated framework materialsEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 4 2008Florian Beuer The purpose of this in vitro study was to compare the load-bearing capacity of posterior three-unit fixed dental prostheses (FDP) produced with three different all-ceramic framework materials: glass-infiltrated alumina (ICA), glass-infiltrated alumina strengthened with zirconia (ICZ), and yttria-stabilized polycrystalline zirconia (YZ). Additionally, the influence on aging of mechanical cyclic fatigue loading and thermal cycling in water were evaluated. A total of 20 frameworks each were fabricated from ICA, ICZ, and YZ by a computer-aided design (CAD)/computer-aided manufacturing (CAM) system. The framework designs were identical for all specimens. All frameworks were veneered with porcelain and cemented with glass,ionomer. Prior to fracture testing, 10 FDP of each experimental group were subjected to thermal and mechanical cycling. Additionally, fractographic analysis was performed. Statistical analysis showed that FDP made from YZ had significantly higher load to failure, whereas no difference was found between the other two materials. Aging did not have a significant effect on the fracture load. [source] Assembly of Pure Silver-Tungsten-Oxide Frameworks from Nanostructured Solution Processable Clusters and Their Evolution into Materials with a Metallic ComponentADVANCED MATERIALS, Issue 38 2010Thomas McGlone Silver-Tungsten-Oxide Frameworks: Isomerically pure forms of the unique isopolyoxotungstate system are incorporated into highly connected framework materials using Ag(I) as a linking unit. Thermal treatment of the materials leads to the formation of silver microparticles embedded in a tungsten oxide matrix. This novel synthetic approach promises to create a new class of nanostructured tungsten-silver-oxides with exciting physical properties, as well as exemplifies the potential for new frameworks based upon solution processable POM clusters. [source] Elucidation of zeolite microstructure by synchrotron X-ray diffuse scatteringJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2 2004B. J. Campbell Single-crystal diffuse scattering measurements can now rapidly probe the three-dimensional structure of subtle defects in microporous framework materials. Diffuse scattering data from natural mordenite crystals are shown to exhibit a complex distribution of weak features which have been mapped out using a synchrotron X-ray source and a CCD detector. Comparison with computer-simulated diffuse scattering patterns yields a detailed three-dimensional columnar defect structure and reveals that roughly one third of the mordenite's columnar defects cooperate to form a block-mosaic pattern of {110} stacking faults. [source] Translucency of glass-fibre-reinforced composite materialsJOURNAL OF ORAL REHABILITATION, Issue 8 2004T. Nakamura summary, The purpose of this study was to examine the translucency of glass-fibre-reinforced composite framework materials. Vectris and FibreKor, as well as an experimental material, were the glass-fibre-reinforced framework materials used. Targis, Sculpture and Estenia were the types of particulate filler composites veneered onto frameworks. Specimens were fabricated from each material, 0·5 and 1·0 mm thick. In addition, laminate specimens, 1·5 mm thick, were fabricated. The translucency of each specimen was evaluated by determining its contrast ratio. The laminate specimens were examined for colour differences. The experimental framework material was more translucent than the enamel composite when it was not coloured, and was nearly as translucent as the dentine composite when coloured. The commercial tooth-coloured framework materials were nearly as translucent as the dentine composite. It was found that it was possible to reproduce the same colour as the veneering dentine composite, when the framework thickness was 0·5 mm, except in the case of FibreKor. Within the limitations of this study, tooth-coloured, glass-fibre-reinforced framework materials are nearly as translucent as the veneering dentine composite, but these materials affect the colour of the prosthesis if the thickness of the framework material is increased beyond a certain point. [source] Laser-Welded Titanium Frameworks Supported by Implants in the Partially Edentulous Mandible: A 10-Year Comparative Follow-Up StudyCLINICAL IMPLANT DENTISTRY AND RELATED RESEARCH, Issue 3 2008Anders Örtorp DDS, PhD/Odont Dr ABSTRACT Background: Comparative long-term knowledge of different framework materials in the partially edentulous implant patient is not available. Purpose: To report and compare 10-year data on free-standing implant-supported partial prostheses with laser-welded titanium (test) and conventional gold alloy (control) frameworks. Materials and Methods: Altogether, 52 partially edentulous patients were consecutively provided with laser-welded prostheses (n = 60) in the partially edentulous lower jaw (test group). A control group of 52 randomly selected patients with gold alloy castings (n = 60) was used for comparison. Clinical and radiographic 10-year data were retrospectively collected and evaluated for both groups. Results: The overall 10-year implant cumulative survival rate (CSR) was 93.0% (loaded implants, 96.4%), with a 10-year implant CSR of 91.5 and 94.7% for test and control implants, respectively (p > .05). Out of a total of 22 lost implants, 17 implants (77.3%) were shorter than 10 mm. The overall 10-year prosthesis CSR was 93.7%, with a corresponding 10-year CSR of 88.4 and 100% for test and control groups, respectively (p < .05). Average 10-year bone loss was 0.46 mm (SD 0.47) and 0.69 mm (SD 0.53) for the test and control groups (p < .001), respectively. Only 1% of the implants had >3 mm accumulated bone loss after 10 years. Altogether, 10 of the prostheses in both groups had implant component mechanical problems (8.3%). None of the frameworks or implants fractured, but more fractures of porcelain veneers were observed in the test group (p < .05). Conclusion: The protocol of implant treatment in the partially edentulous jaw functioned well during 10 years, although prosthodontic maintenance was required. However, laser-welded titanium frameworks presented more problems as compared with gold alloy frameworks. More loaded implants were lost (p < .05), and higher incidence of porcelain chipping was noted in the test group (p < .05). However, bone loss was on an average lower for the test group during the 10 years of follow-up (p < .001). [source] | |||||||||||||