Silicon diffusion in a natural quartz aggregate: constraints on solution-transfer diffusion creep

The InGaAlP quaternary system allows the production of semiconductor lasers emitting light in the visible range of the spectrum. Recent advances in the visible semiconductor diode laser art have established the viability of diode structures with emission wavelengths comparable to the He-Ne gas laser. There has been much interest in the growth of wide bandgap quaternary thin films on GaAs, a substrate most commonly used in optoelectronic applications. There is particular interest in compositions which are lattice matched to GaAs, thus avoiding misfit dislocations which can be detrimental to the lifetime of these materials. As observed in Figure 1, the (AlxGa1-x)0.5In0.5P system has a very close lattice match to GaAs and is favored for these applications.In this work, we have studied the effect of silicon diffusion in GaAs/InGaAlP structures. Silicon diffusion in III-V semiconductor alloys has been found to have an disordering effect which is associated with removal of fine structures introduced during growth. Due to the variety of species available for interdiffusion, the disordering effect of silicon can have severe consequences on the lattice match at GaAs/InGaAlP interfaces.

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Anatomy and ultrastructure of haustoria in selected West Australian parasitic angiosperms

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010016100x ◽

1990 ◽

Vol 48 (3) ◽

pp. 690-691

Author(s):

John Kuo ◽

John S. Pate

Keyword(s):

Parasitic Plants ◽

The Other ◽

Nutrient Transfer ◽

Direct Solution ◽

Tracheary Elements ◽

Solute Transfer ◽

Glycol Methacrylate ◽

Australian Species ◽

Anatomy And Ultrastructure ◽

Solution Transfer

Our understanding of nutrient transfer between host and flowering parasitic plants is usually based mainly on physiological concepts, with little information on haustorial structure related to function. The aim of this paper is to study the haustorial interface and possible pathways of water and solute transfer between a number of host and parasites.Haustorial tissues were fixed in glutaraldehyde and embedded in glycol methacrylate (LM), or fixed in glutaraldehyde then OsO4 and embedded in Spurr’s resin (TEM).Our study shows that lumen to lumen continuity occurs between tracheary elements of a host and four S.W. Australian species of aerial mistletoes (Fig. 1), and some root hemiparasites (Exocarpos spp. and Anthobolus foveolatus) (Fig. 2). On the other hand, haustorial interfaces of the root hemiparasites Olax phyllanthi and Santalum (2 species) are comprised mainly of parenchyma, as opposed to terminating tracheads or vessels, implying that direct solution transfer between partners via vessels or tracheary elements may be limited (Fig. 3).

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Studies of Nucleation and Propagation of Cracks in Natural Quartz

The Journal of Gemmology ◽

10.15506/jog.1976.15.3.129 ◽

1976 ◽

Vol 15 (3) ◽

pp. 129-135 ◽

Cited By ~ 1

Author(s):

M. S. Joshi ◽

B. K. Paul

Keyword(s):

Natural Quartz

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The role of sodium ions in the thermoluminescence peaks of laboratory-irradiated natural quartz

Radiation Measurements ◽

10.1016/j.radmeas.2021.106539 ◽

2021 ◽

Vol 141 ◽

pp. 106539

Author(s):

Tran Ngoc ◽

Ho Van Tuyen ◽

Le Anh Thi ◽

Le Xuan Hung ◽

Nguyen Xuan Ca ◽

...

Keyword(s):

Sodium Ions ◽

Natural Quartz

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An investigation of the nuclear shielding effectiveness of some transparent glasses manufactured from natural quartz doped lead cations

Nuclear Engineering and Technology ◽

10.1016/j.net.2020.12.023 ◽

2020 ◽

Author(s):

Said M. Kassem ◽

G.S.M. Ahmed ◽

A.M. Rashad ◽

S.M. Salem ◽

S. Ebraheem ◽

...

Keyword(s):

Shielding Effectiveness ◽

Natural Quartz ◽

Nuclear Shielding

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A Study of the Impact of Graphite on the Kinetics of SPS in Nano- and Submicron WC-10%Co Powder Compositions

Ceramics ◽

10.3390/ceramics4020025 ◽

2021 ◽

Vol 4 (2) ◽

pp. 331-363

Author(s):

Eugeniy Lantcev ◽

Aleksey Nokhrin ◽

Nataliya Malekhonova ◽

Maksim Boldin ◽

Vladimir Chuvil'deev ◽

...

Keyword(s):

Activation Energy ◽

Solid Phase ◽

Continuous Heating ◽

Diffusion Creep ◽

Hard Alloys ◽

Fine Grained ◽

Plasma Sintering ◽

Spark Plasma ◽

The Impact ◽

Kinetics Of

This study investigates the impact of carbon on the kinetics of the spark plasma sintering (SPS) of nano- and submicron powders WC-10wt.%Co. Carbon, in the form of graphite, was introduced into powders by mixing. The activation energy of solid-phase sintering was determined for the conditions of isothermal and continuous heating. It has been demonstrated that increasing the carbon content leads to a decrease in the fraction of η-phase particles and a shift of the shrinkage curve towards lower heating temperatures. It has been established that increasing the graphite content in nano- and submicron powders has no significant effect on the SPS activation energy for “mid-range” heating temperatures, QS(I). The value of QS(I) is close to the activation energy of grain-boundary diffusion in cobalt. It has been demonstrated that increasing the content of graphite leads to a significant decrease in the SPS activation energy, QS(II), for “higher-range” heating temperatures due to lower concentration of tungsten atoms in cobalt-based γ-phase. It has been established that the sintering kinetics of fine-grained WC-Co hard alloys is limited by the intensity of diffusion creep of cobalt (Coble creep).

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