scholarly journals Capillary Action Around Dental Structures

1973 ◽  
Vol 52 (3) ◽  
pp. 544-550 ◽  
Author(s):  
W.J. O'Brien

The capillary action of saliva occurs in the crevices around and between teeth and around dental restorations. Marginal leakage and denture retention caused by a thin film of saliva are aspects of capillary phenomena. Liquids in capillaries isolated from a reservoir showed an increase in surface tension and lower vapor pressure. The strength of thin films of human saliva was independent of ambient pressure.

2013 ◽  
Vol 80 (2) ◽  
Author(s):  
Yong Wang ◽  
Xue Feng ◽  
Bingwei Lu ◽  
Gangfeng Wang

The buckling of thin films with natural nonlinearity can provide a useful tool in many applications. In the present paper, the mechanical properties of controllable buckling of thin films are investigated by accounting for both geometric nonlinearity and surface effects at nanoscale. The effects of surface elasticity and residual surface tension on both static and dynamic behaviors of buckled thin films are discussed based on the surface-layer-based model. The dynamic design strategy for buckled thin films as interconnects in flexible electronics is proposed to avoid resonance in a given noise environment based on the above analysis. Further discussion shows that the thermal and piezoelectric effects on mechanical behavior of buckled thin film are equivalent to that of residual surface tension.


2016 ◽  
Vol 23 (03) ◽  
pp. 1650009 ◽  
Author(s):  
İ. A. KARIPER

This study examines the critical surface energy of manganese sulfite (MnSO[Formula: see text] crystalline thin film, produced via chemical bath deposition (CBD) on substrates. In addition, parachor, which is an important parameter of chemical physics, and its relationship with grain size, film thickness, etc., has been investigated for thin films. For this purpose, MnSO3 thin films were deposited at room temperature using different deposition times. Structural properties of the films, such as film thickness and average grain size, were examined using X-ray diffraction; film thickness and surface properties were measured by and atomic force microscope; and critical surface tension of MnSO3 thin films was measured with Optical Tensiometer and calculated using Zisman method. The results showed that critical surface tension and parachor of the films have varied with average grain size and film thickness. Critical surface tension was calculated as 32.97, 24.55, 21.03 and 12.76[Formula: see text]mN/m for 14.66, 30.84, 37.07 and 44.56[Formula: see text]nm grain sizes, respectively. Film thickness and average grain size have been increased with the deposition time and they were found to be negatively correlated with surface tension and parachor. The relationship between film thickness and parachor was found as [Formula: see text] whereas the relationship between average grain size and parachor was found as [Formula: see text] We also showed the relationships between parachor and some thin films parameters.


1981 ◽  
Vol 4 ◽  
Author(s):  
S. P. Tobin ◽  
A. C. Greenwald ◽  
R. G. Wolfson ◽  
T. T. Wong

ABSTRACTWe have developed a novel technique for improving the morphology of as-grown monocrystalline thin films on foreign substrates. A pulsed electron beam briefly heats the surface of the film above its melting temperature, allowing surface tension in the liquid to erase irregular features. Crystallinity of the layer is preserved by rapid resolidification with the underlying material acting as a seed. Pulse polishing has been applied to two heteroepitaxial systems exhibiting rough as-deposited surfaces: germanium on silicon and cadmium telluride on mica. In both cases the surface morphology was dramatically improved while crystallinity and other critical properties of the layers were maintained. We believe this technique has potentially wide application to many thin film systems and should allow a greater degree of freedom in the growth conditions for heteroepitaxial thin films.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Firoz Alam ◽  
David J. Lewis

AbstractFormamidinium lead iodide (CH(NH2)2PbI3, FAPI) thin films have been deposited on glass substrates at 150 °C using ambient pressure aerosol assisted chemical vapour deposition (AACVD). The films have been analysed by a range of techniques including powder X-ray diffraction (pXRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, and UV–Vis–NIR absorption spectroscopy. Sharp reflections in the pXRD pattern can be indexed to the α-phase of FAPI which confirms the crystallinity of the as-deposited film and reveals a preferred growth orientation along the (002) plane with respect to the substrate. High magnification SEM images show that the thin film is comprised of a network of intimately connected FAPI crystallites which form a mesoporous architecture. EDX mapping of lead and iodine emission peaks show that the Pb and I within these films are spatially co-localised. Optical measurements show as-deposited FAPI films have absorption onsets in the near infra-red with a direct bandgap value of 1.46 eV, suitable for single junction solar cells. Four-point probe measurement of as deposited films show that the electrical conductivity (σ) of the FAPI thin film is 5.2 × 10–7 S/cm, which is similar to FAPI thin films deposited by spin coating technique.


2018 ◽  
Vol 47 (40) ◽  
pp. 14179-14183 ◽  
Author(s):  
Raghavender Medishetty ◽  
Zongji Zhang ◽  
Alexander Sadlo ◽  
Stefan Cwik ◽  
Daniel Peeters ◽  
...  

Fabrication of 3-dimensional MOF thin films has been investigated through the conversion of ZnO thin film via a pure vapour–solid deposition reaction at ambient pressure.


2003 ◽  
Vol 764 ◽  
Author(s):  
Hong Seong Kang ◽  
Jeong Seok Kang ◽  
Jae Won Kim ◽  
Sang Yeol Lee

AbstractZnO thin films and ZnO-Si-ZnO multi-layer thin films have been deposited by pulsed laser deposition (PLD). And then, the films have been annealed at 300°C in oxygen ambient pressure. The optical and structural properties changed by Si layer in ZnO thin film. UV and visible peak position was shifted by Si layer. Electrical properties of the films were improved slightly than ZnO thin film without Si layer. The optical and structural properties of ZnO thin films and ZnOSi-ZnO multi-layer thin films were characterized by PL (Photoluminescence) and XRD(X-ray diffraction method), respectively. Electrical properties were measured by van der Pauw Hall measurements.


Author(s):  
R. C. Moretz ◽  
G. G. Hausner ◽  
D. F. Parsons

Use of the electron microscope to examine wet objects is possible due to the small mass thickness of the equilibrium pressure of water vapor at room temperature. Previous attempts to examine hydrated biological objects and water itself used a chamber consisting of two small apertures sealed by two thin films. Extensive work in our laboratory showed that such films have an 80% failure rate when wet. Using the principle of differential pumping of the microscope column, we can use open apertures in place of thin film windows.Fig. 1 shows the modified Siemens la specimen chamber with the connections to the water supply and the auxiliary pumping station. A mechanical pump is connected to the vapor supply via a 100μ aperture to maintain steady-state conditions.


Author(s):  
M. Grant Norton ◽  
C. Barry Carter

Pulsed-laser ablation has been widely used to produce high-quality thin films of YBa2Cu3O7-δ on a range of substrate materials. The nonequilibrium nature of the process allows congruent deposition of oxides with complex stoichiometrics. In the high power density regime produced by the UV excimer lasers the ablated species includes a mixture of neutral atoms, molecules and ions. All these species play an important role in thin-film deposition. However, changes in the deposition parameters have been shown to affect the microstructure of thin YBa2Cu3O7-δ films. The formation of metastable configurations is possible because at the low substrate temperatures used, only shortrange rearrangement on the substrate surface can occur. The parameters associated directly with the laser ablation process, those determining the nature of the process, e g. thermal or nonthermal volatilization, have been classified as ‘primary parameters'. Other parameters may also affect the microstructure of the thin film. In this paper, the effects of these ‘secondary parameters' on the microstructure of YBa2Cu3O7-δ films will be discussed. Examples of 'secondary parameters' include the substrate temperature and the oxygen partial pressure during deposition.


Author(s):  
P. Lu ◽  
W. Huang ◽  
C.S. Chern ◽  
Y.Q. Li ◽  
J. Zhao ◽  
...  

The YBa2Cu3O7-x thin films formed by metalorganic chemical vapor deposition(MOCVD) have been reported to have excellent superconducting properties including a sharp zero resistance transition temperature (Tc) of 89 K and a high critical current density of 2.3x106 A/cm2 or higher. The origin of the high critical current in the thin film compared to bulk materials is attributed to its structural properties such as orientation, grain boundaries and defects on the scale of the coherent length. In this report, we present microstructural aspects of the thin films deposited on the (100) LaAlO3 substrate, which process the highest critical current density.Details of the thin film growth process have been reported elsewhere. The thin films were examined in both planar and cross-section view by electron microscopy. TEM sample preparation was carried out using conventional grinding, dimpling and ion milling techniques. Special care was taken to avoid exposure of the thin films to water during the preparation processes.


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