Influence of Concentration Distribution on Cross Diffusion Level in Building Room

The relationship of contaminant gas concentration distribution influence on cross diffusion character and level among temperature, humidity and contaminant gas concentration was obtained according to the non-equilibrium thermodynamic theory. The cross diffusion character and level under different contaminant gas concentration distribution were discussed, combining real temperature and humidity in building room. The results show that temperature grads and vapor mass grads are less than zero when contaminant gas mass grads and additional diffusion coefficient are both positive or negative, otherwise the two grads are more than zero. And the higher the initial temperature and humidity levels, the greater the absolute values of temperature grads and vapor mass grads, with the same contaminant gas mass grads and additional diffusion coefficient. While the influence of initial temperature level is finite, and that of initial humidity level is remarkable.

Direct bonding of silicon with solders type Sn-Ag-Ti

Purpose The work aims to study the direct bonding of silicon substrate with solders type Sn-Ag-Ti. Design/methodology/approach During the bonding process with ultrasound assistance, the active element (Ti,Ce,Mg) is distributed from the solder to interface with a silicon substrate, where it supports the bond formation. Findings Formation of a reaction layer, 1-2 μm in thickness, was observed. The new Si2Ti phases and Mg2Si phase were identified in the reaction layer. Originality/value The results of analysis suggest that the Si/Sn-Ag-Ti joint is of diffusion character. The highest average strength on silicon substrate (39 MPa) was achieved with Sn-Ag-Ti(Mg) solder.

Research of Joining Brittle Nonmetallic Materials with an Active Solder

This paper deals with soldering high-purity brittle, nonmetallic materials such as SiO2, Si, and C (graphite). However, these materials exert poor wettability when using tin solder. Therefore, to reduce the wetting angle, an Sn solder alloyed with active Ti element was used. At a soldering temperature of 860°C and 15 min soldering time, the wetting angle on SiO2ceramics was 30°, on silicon 42°, and on graphite 52°. All these wetting angles are below 90° and are acceptable for soldering. It has been shown that the bond in all joined materials (SiO2, Si, and C) was of a diffusion character. New intermetallic products were formed on the boundary with nonmetal, thus allowing bond formation. The shear strength of SiO2ceramics attained an average value of 17 MPa.

Glow discharge treatment of Inconel 625 for glass fibreizing spinner discs

Fibreizing spinner discs work in absolutely extreme conditions. They are exposed to the influences of high temperatures, oxidation at elevated temperatures, combustion gases, and liquid glass. The spinner discs usually used are made from Inconel 625 alloys. Liquid glass affects the chemical composition of the Inconel surface zone, decreasing the chromium content. This causes corrosion phenomena. The recent studies concerning the application of CrN layers to protect the spinner disc against the external environment are presented. It has been shown that CrN layers improve the lifetime of the spinner disc. Produced CrN layers have diffusion character, hardness ∼1700 HV 0.05, and high wear and corrosion resistance.

Modelling of Moisture Sorption by Cfrp Rebars with Vinylester Matrix

The results of experimental investigation and modelling of moisture sorption by CFRP rebars and vinylester matrix are presented. Experimental values of the rebar diffusion coefficients essentially differ from those predicted using structural approach. Essential anisotropy of sorption process in longitudinal and transverse directions is observed. Quasi three phase model is suggested for description of the CFRP rebar sorption. The model is based on consideration of sorption process of the diffusion character in the composite consisted of two phases: resin and microplastic, which includes fibres and fibre-resin interphase. The suggested model describes the experimental sorption data quite satisfactorily and explains high anisotropy effect.

Diffusion Character in Four-Dimensional Volume-Preserving Map

Due to the existence of invariant tori, chaotic sea and hyperbolic structures in higher dimensional phase space of a volume-preserving map, the diffusion route of chaotic orbits will be complicated. The velocity of diffusion will be very slow if the orbits are near an invariant torus. In order to realize this complicated diffusion phenomenon, in this paper we study the diffusion characters in the different regions, i.e., chaotic, hyperbolic and invariant tori’s regions. We find that for the three different regions, the diffusion velocities are different. The diffusion velocity in the vicinity of an invariant torus is the slowest one.

Small-intestinal transfer mechanism of prunasin, the primary metabolite of the cyanogenic glycoside amygdalin

1 The small-intestinal transfer of prunasin (D-mandelo nitrile-β-D-glucoside), the primary metabolite of amyg dalin which is not absorbed in the small intestine as such, was studied in rat jejunum and ileum in vitro. 2 As shown by high pressure liquid chromatography, prunasin is transferred essentially intact across the intesti nal wall, without cleavage of the glycosidic bond and thus no formation of benzaldehyde or cyanide during the mucosal passage. 3 Only the jejunal transfer of prunasin followed satura tion kinetics (vmax = 1.6 μmol cm-1 min-1; KT = 460 μmol l-1) and exhibited a clearsodium-ion dependence. As indicated by the temperature dependence, only the jejunal mucosa- to-serosa transfer and the corresponding tissue uptake of prunasin required apparently high activation energies. Transfer in the terminal ileum showed diffusion character istics. 4 Jejunal methyl α-D-glucoside transfer was inhibited by the presence of prunasin. Furthermore, the tissue uptake of methyl α-D-glucoside in rat jejunum was competitively inhibited by prunasin. 5 The results indicate that prunasin is absorbed unmetabolised in the jejunum of the rat via the transport system of glucose.