Growth conditions of manganese nodules comparative studies of growth rate, magnetization, chemical composition and internal structure

1978 ◽  
Vol 7 (5-6) ◽  
pp. 163-239 ◽  
Author(s):  
Dietrich Heye
Keyword(s):  
Growth Rate ◽  
Chemical Composition ◽  
Internal Structure ◽  
Comparative Studies ◽  
Growth Conditions ◽  
Manganese Nodules

Preparation and characterization of epitaxial iron oxide films

1998 ◽  
Vol 13 (7) ◽  
pp. 2003-2014 ◽  
Author(s):  
Y. Gao ◽  
Y. J. Kim ◽  
S. A. Chambers
Keyword(s):  
Growth Rate ◽  
Iron Oxide ◽  
Oxygen Plasma ◽  
Film Surface ◽  
Surface Region ◽  
Growth Conditions ◽  
Epitaxial Films ◽  
Pure Phase ◽  
Iron Oxide Films

Well-ordered, pure-phase epitaxial films of FeO, Fe3O4, and γ–Fe2O3 were prepared on MgO(001) by oxygen-plasma-assisted MBE. The stoichiometries of these thin films were controlled by varying the growth rate and oxygen partial pressure. Selective growth of γ–Fe2O3 and α–Fe2O3 was achieved by controlling the growth conditions in conjunction with the choice of appropriate substrates. Growth of the iron oxide epitaxial films on MgO at ≥350 °C is accompanied by significant Mg outdiffusion. The FeO(001) film surface exhibits a (2 × 2) reconstruction, which is accompanied by a significant amount of Fe3+ in the surface region. Fe3O4 (001) has been found to reconstruct to a structure. γ–Fe23 (001) film surface is unreconstructed.

Thermal Parameters, Microstructure and Porosity During Transient Solidification of Ternary Al–Cu–Si Alloys

2012 ◽  
Vol 730-732 ◽  
pp. 883-888 ◽  
Author(s):  
Daniel J. Moutinho ◽  
Laércio G. Gomes ◽  
Otávio L. Rocha ◽  
Ivaldo L. Ferreira ◽  
Amauri Garcia
Keyword(s):  
Growth Rate ◽  
Chemical Composition ◽  
Cooling Rate ◽  
Tip Growth ◽  
Thermal Parameters ◽  
Volumetric Fraction ◽  
Dendritic Network ◽  
Intermetallic Particles ◽  
Casting Length

Solidification of ternary Al-Cu-Si alloys begins with the development of a complex dendritic network typified by primary (λ1) and secondary (λ2) dendrite arm spacings which depend on the chemical composition of the alloy and on the casting thermal parameters such as the growth rate and the cooling rate. These thermal parameters control the scale of dendritic arms, the size and distribution of porosity and intermetallic particles in the casting. In this paper, λ1and λ2were correlated with experimental thermal parameters i.e., the tip growth rate and the tip cooling rate. The porosity profile along the casting length has also been experimentally determined. The volumetric fraction of pores increase with the increase in alloying Si and with the increase in Fe concentration at the regions close to the casting cooled surface.

Emission characteristics of GaInN/GaN multiple quantum shell nanowire-based LEDs with different p-GaN growth conditions

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sae Katsuro ◽  
Weifang Lu ◽  
Kazuma Ito ◽  
Nanami Nakayama ◽  
Naoki Sone ◽  
...  
Keyword(s):  
Growth Rate ◽  
Shell Growth ◽  
Light Output ◽  
High Growth ◽  
Growth Conditions ◽  
High Growth Rate ◽  
Current Injection ◽  
Emission Characteristics ◽  
Multiple Quantum ◽  
Plane Region

Abstract Improving current injection into r- and m-planes of nanowires (NWs) is essential to realizing efficient GaInN/GaN multiple quantum shell (MQS) NW-based light-emitting diodes (LEDs). Here, we present the effects of different p-GaN shell growth conditions on the emission characteristics of MQS NW-LEDs. Firstly, a comparison between cathodoluminescence (CL) and electroluminescence (EL) spectra indicates that the emission in NW-LEDs originates from the top region of the NWs. By growing thick p-GaN shells, the variable emission peak at around 600 nm and degradation of the light output of the NW-LEDs are elaborated, which is attributable to the localization of current in the c-plane region with various In-rich clusters and deep-level defects. Utilizing a high growth rate of p-GaN shell, an increased r-plane and a reduced c-plane region promote the deposition of indium tin oxide layer over the entire NW. Therefore, the current is effectively injected into both the r- and m-planes of the NW structures. Consequently, the light output and EL peak intensity of the NW-LEDs are enhanced by factors of 4.3 and 13.8, respectively, under an injection current of 100 mA. Furthermore, scanning transmission electron microscope images demonstrate the suppression of dislocations, triangular defects, and stacking faults at the apex of the p-GaN shell with a high growth rate. Therefore, localization of current injection in nonradiative recombination centers near the c-plane was also inhibited. Our results emphasize the possibility of realizing high efficacy in NW-LEDs via optimal p-GaN shell growth conditions, which is quite promising for application in the long-wavelength region.

Differences in Chemical Composition and Internal Structure Influence Systemic Host Response to Implants of Biomaterials

2011 ◽  
Vol 34 (5) ◽  
pp. 422-431 ◽  
Author(s):  
Silvia Scaglione ◽  
Michele Cilli ◽  
Mauro Fiorini ◽  
Rodolfo Quarto ◽  
Giuseppina Pennesi
Keyword(s):  
Chemical Composition ◽  
Internal Structure ◽  
Host Response

scholarly journals Influence of stress conditions on the quality of obtained sprouts – modification of their chemical composition

2021 ◽  
Vol 13 (2) ◽  
pp. 1-12
Author(s):  
Magdalena Zielińska-Dawidziak
Keyword(s):  
Chemical Composition ◽  
Secondary Metabolites ◽  
Metal Ions ◽  
Nutritional Quality ◽  
Growth Conditions ◽  
Stress Conditions ◽  
Light Illumination ◽  
Health Promoting ◽  
Chemical Factors

Sprouts are generally accepted as a pro-healthy food. They are consumed as a source of valuable macronutrients, antioxidants, microelements, and vitamins. Changing growth conditions of sprouts enables modification of their nutritional quality, as well as their safety. Thus, in order to achieve the most desirable composition of the produced sprouts, the conditions for their production are optimized. The aim of this review is to present methods currently used to modify the nutritional quality of plant sprouts. Most scientific works focus on stress conditions inducing the synthesis of secondary metabolites, mainly antioxidants. An increase in their content is achieved after application of physical (e.g., light illumination, temperature) or chemical factors (e.g., salinity stress, phytohormones, metal ions, etc). Though the application of these modifications on a larger scale is problematic. These problems include difficulties in predicting the effect of the stressor and an increased price of the obtained sprouts. However, since it is possible to enrich sprouts with valuable health-promoting substances, these methods are still considered very promising.

scholarly journals <sup>210</sup>Pb-<sup>226</sup>Ra chronology reveals rapid growth rate of <i>Madrepora oculata</I> and <i>Lophelia pertusa</i> on world's largest cold-water coral reef

2011 ◽  
Vol 8 (6) ◽  
pp. 12247-12283
Author(s):  
P. Sabatier ◽  
J.-L. Reyss ◽  
J. M. Hall-Spencer ◽  
C. Colin ◽  
N. Frank ◽  
...  
Keyword(s):  
Growth Rate ◽  
Coral Reef ◽  
Linear Growth ◽  
Cold Water ◽  
Optimal Growth ◽  
Growth Conditions ◽  
Age And Growth ◽  
Linear Growth Rate ◽  
Lophelia Pertusa ◽  
Water Coral

Abstract. Here we show the use of the 210Pb-226Ra excess method to determine the growth rate of corals from one of the world's largest known cold-water coral reef, the Røst Reef off Norway. Two large branching framework-forming cold-water coral specimens, one Lophelia pertusa and one Madrepora oculata were collected alive at 350 m water depth from the Røst Reef at ~67° N and ~9° E. Pb and Ra isotopes were measured along the major growth axis of both specimens using low level alpha and gamma spectrometry and the corals trace element compositions were studied using ICP-QMS. Due to the different chemical behaviors of Pb and Ra in the marine environment, 210Pb and 226Ra were not incorporated the same way into the aragonite skeleton of those two cold-water corals. Thus to assess of the growth rates of both specimens we have here taken in consideration the exponential decrease of initially incorporated 210Pb as well as the ingrowth of 210Pb from the decay of 226Ra. Moreover a~post-depositional 210Pb incorporation is found in relation to the Mn-Fe coatings that could not be entirely removed from the oldest parts of the skeletons. The 226Ra activities in both corals were fairly constant, then assuming constant uptake of 210Pb through time the 210Pb-226Ra chronology can be applied to calculate linear growth rate. The 45.5 cm long branch of M. oculata reveals an age of 31 yr and a~linear growth rate of 14.4 ± 1.1 mm yr−1, i.e. 2.6 polyps per year. However, a correction regarding a remaining post-depositional Mn-Fe oxide coating is needed for the base of the specimen. The corrected age tend to confirm the radiocarbon derived basal age of 40 yr (using 14C bomb peak) with a mean growth rate of 2 polyps yr−1. This rate is similar to the one obtained in Aquaria experiments under optimal growth conditions. For the 80 cm-long specimen of L. pertusa a remaining contamination of metal-oxides is observed for the middle and basal part of the coral skeleton, inhibiting similar accurate age and growth rate estimates. However, the youngest branch was free of Mn enrichment and this 15 cm section reveals a growth rate of 8 mm yr−1 (~1 polyp every two to three years). However, the 210Pb growth rate estimate is within the lowermost ranges of previous growth rate estimates and may thus reflect that the coral was not developing at optimal growth conditions. Overall, 210Pb-226Ra dating can be successfully applied to determine the age and growth rate of framework-forming cold-water corals, however, removal of post-depositional Mn-Fe oxide deposits is a prerequisite. If successful, large branching M. oculata and L. pertusa coral skeletons provide unique oceanographic archive for studies of intermediate water environmentals with an up to annual time resolution and spanning over many decades.

In Situ Monitoring of the Smear-Out of the Ge Profile in GAS Source SiGe MBE Using Rheed Intensity Oscillations

1992 ◽  
Vol 263 ◽  
Author(s):  
K. Werner ◽  
S. Butzke ◽  
J.W. Maes ◽  
O.F.Z. Schannen ◽  
J. Trommel ◽  
...  
Keyword(s):  
Growth Rate ◽  
Molecular Beam ◽  
Surface Segregation ◽  
Catalytic Effect ◽  
Growth Conditions ◽  
In Situ Monitoring ◽  
Marked Contrast ◽  
Si Substrates ◽  
Gas Source

ABSTRACTWe have studied the deposition of GexSi1−x layers on (100) Si substrates by gas source molecular beam epitaxy (GSMBE) using disilane and germane.The investigation of RHEED intensity oscillations during growth reveals the well known rate enhancement obtained when adding a small amount of germane to the disilane flux. However, when exposing a previously deposited Ge layer to a pure disilane flux the growth rate during the first few monolayers remains at an enhanced value but returns to its homoepitaxial value after about 10 to 15 monolayers. This behaviour was observed under a variety of growth conditions. It is in marked contrast to the experience obtained in conventional Si/Ge MBE and suggests a catalytic effect of the particular surface present during GSMBE growth. We propose that this effect is caused by the surface segregation of Ge species and leads to a smear-out of the Ge profile in the layer.

Рентгенофлюоресцентный анализ металлических изделий из скального погребения Узуур-Гялана (Монгольский Алтай)

2021 ◽  
Author(s):  
Мунхбаяр Б.Ч. ◽  
Keyword(s):  
Chemical Composition ◽  
Comparative Studies ◽  
Ferrous Metal ◽  
Tenth Century ◽  
Cultural Relations ◽  
Local Characteristics ◽  
Ferrous Metals ◽  
Metal Products ◽  
Non Ferrous Metals ◽  
The Comparative Study

The article describes the metalwork of the Uzuur Gyalan rock burial, popularly known online in 2016 as the «Adidas Mummy». The definitions and chemical composition of the metalware were compared with those of the time in the region. According to the results of the comparative study, the composition of the bronze mirror is very different from other bronze objects. However, bridles, saddle plaques, and ligaments are similar to the main non-ferrous metals in the region, but appear to have local characteristics. Further detailed comparative studies of the chemical composition of non-ferrous metal products in the tenth century are important steps in establishing regional cultural relations.

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