The orthoclase-microcline inversion

1954 ◽  
Vol 30 (225) ◽  
pp. 354-366 ◽  
Author(s):  
Wm. Scott MacKenzie
Keyword(s):  
Optical Properties ◽  
Low Temperature ◽  
Relative Stability ◽  
Temperature Modification ◽  
Potash Felspar ◽  
Lower Temperature ◽  
Relationship Of ◽  
Multiple Twinning ◽  
The Relationship

The association of orthoclase and microcline in the same rock has been commented on by many writers, and from these occurrences attempts have been made to deduce the relative stability of these two low-temperature forms of potash-felspar. Ahnost all investigators have concluded that nlicrocline is the lower-temperature modification, but difficulties in explaining the relationship of adutaria to orthoclase and microcline have been encountered.The identification of the monoclinie potash-felspar in association with microcline is almost always based on optical properties, viz. straight extinction in the zone [010] or the absence of visible multiple twinning.

Relationship of basal plane and prismatic stacking faults in GaN to low temperature photoluminescence peaks at ∼3.4 eV and ∼3.2 eV

2004 ◽  
Vol 831 ◽  
Author(s):  
J. Bai ◽  
M. Dudley ◽  
L. Chen ◽  
B. J. Skromme ◽  
P. J. Hartlieb ◽  
...  
Keyword(s):  
Low Temperature ◽  
Thin Layer ◽  
Basal Plane ◽  
Stacking Faults ◽  
Structural Defects ◽  
Cubic Phase ◽  
Bulk Crystals ◽  
Relationship Of ◽  
The Relationship ◽  
Low Temperature Photoluminescence

ABSTRACTThe relationship between the optical properties and microstructure of GaN is of great interest due to the important optical and electronic applications of this material. Several different studies have been reported attempting to link the low temperature photoluminescence (PL) peak at ∼3.4 eV to the presence of various microstructural defects. However, no clear systematic studies have been reported establishing such a link for the PL peak observed at ∼3.2 eV. In this paper, we present evidence linking the ∼3.4 eV PL peak to the presence of a thin layer of cubic phase associated with basal plane stacking faults (BSF). This relationship is mainly established by studying a series of ammonothermally-grown GaN bulk crystals. The existence and strength of the ∼3.4 eV peak are found to be related to the I2 type BSF (RI2=1/3<1>) observed in these samples. To investigate the relationship between the ∼3.2 eV peak and structural defects, a series of GaN epilayers grown on either SiC or sapphire (of various off-cut angles) was investigated by TEM and PL spectroscopy. Samples grown on 3.5° off-cut SiC and 5° and 9° off-cut sapphire substrates exhibit PL peaks near ∼3.2 and ∼3.4 eV, which are absent in the on-axis SiC and sapphire cases. TEM shows that the former group of samples has defect configurations consisting of prismatic stacking faults (PSFs) folding back and forth between two different {1120} planes connected by stair rod dislocations, which in turn fold onto to I1 type BSFs again with stair rod dislocations at the fault intersections. The ∼3.2 eV PL peaks are proposed to possibly arise from transitions involving the PSFs and the stair rods associated with their mutual intersections and their intersections with the BSFs. The ∼3.4 eV peak is again attributed to the thin layer of cubic phase associated with the I1 type BSF (three bilayers as opposed to four bilayers for the I2 type BSF).

The Effect of Different Doping Methods of Sintering Aids on the Barium Titanate Based X7R Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 83-86 ◽  
Author(s):  
C. Ma ◽  
X.H. Wang ◽  
R.Z. Chen ◽  
Long Tu Li ◽  
Zhi Lun Gui
Keyword(s):  
Rare Earth ◽  
Dielectric Loss ◽  
Barium Titanate ◽  
Low Temperature ◽  
Rare Earth Oxide ◽  
Sintering Aids ◽  
Sintering Properties ◽  
Relationship Of ◽  
The Relationship

The barium titanate based X7R ceramics, which are doped with rare earth oxide, Nb2O5, Co3O4 and ZnO-B2O3, could be sintered at a rather low temperature to satisfy the X7R requirements with good permittivity and dielectric loss. In this paper, different doping methods of sintering aids have been used to prepare X7R BaTiO3 ceramics. Samples were sintered at a low temperature and the relationship of doping methods and sintering properties has been concluded.

scholarly journals Sclerotia Formation of Phlebopus Portentosus in Wild and Artificial Cultivation

2021 ◽  
Author(s):  
Tian-Wei Yang ◽  
Jing Liu ◽  
Xin-Jing Xu ◽  
Ming-Xia He ◽  
Feng Gao ◽  
...  
Keyword(s):  
Edible Mushroom ◽  
Whole Process ◽  
Edible Fungus ◽  
Water Drops ◽  
Set Up ◽  
Lower Temperature ◽  
Relationship Of ◽  
First Time ◽  
The Relationship ◽  
Sclerotium Formation

Abstract Phlebopus portentosus is a favorite wild edible mushroom in the Xishuangbanna region, Yunnan, China and in northern Thailand. This bolete has a unique biotrophy. It can be saprobic but also form a tripartite association with root mealy bugs and plants. P. portentosus is the only edible fungus of Boletales in the world that can be cultivated artificially and anniversary produced at present. Sclerotium is often found at its natural environment and cultivated media, but the regularity and growth characteristics of the sclerotium are unknown. In this study the whole process of birth, growth, death and rebirth of the sclerotium of P. portentosus at the national and lab conditions was reported for the first time. The sclerotium formation in the nature is related to adversity, such as reduced rainfall and low temperature. The more rainfall, the less sclerotia. It seems that the lower temperature increased the sclerotium formation, however the relationship of the sclerotium formation to temperature was not obvious as the rainfall. Under artificial conditions the sclerotium formation of P. portentosus is related to the fungus physiological maturation, and the sclerotium occurrence always accompanied by appearance of the water drops on the colony. The result will set up a platform for research on importance of the sclerotium in life circle of P. portentosus.

The relationship of orthopyroxene to pigeonite

1947 ◽  
Vol 28 (198) ◽  
pp. 164-172 ◽  
Author(s):  
Arie Poldervaart
Keyword(s):  
Optical Properties ◽  
Chemical Composition ◽  
Polarized Light ◽  
Number Of Publications ◽  
Relationship Of ◽  
The Relationship

Interest in the orthopyroxene series is evidenced by the great number of publications on that subject which appeared in the literature. Correlations of the chemical composition and optical properties were attempted by Winchell (1923, 1933), Walls (1935), Henry (1935), and Hess and Phillips (1940). The nomenclature of the series was discussed by Winchell (1923), Alling (1936), and Hess and Phillips (1940). The obscure phenomena exhibited by certain orthopyroxenes in polarized light, attributed by some to twinning, by others to exsolution, was noted by a great many petrologists, of whom are mentioned here Lewis (1908), Holmes and Harwood (1928), Guimarães (1933), Scholtz (1936), Hess and Phillips (1938, 1940), Kuschke (1939), Wager and Deer (1939), Nel (1940), Walker (1940, 1943), Walker and Poldervaart (1940, 1941), Edwards (1942), Henry (1942), and Poldervaart (1944, 1946).

scholarly journals STUDY ON TEMPERATURE FIELD OF ASYMMETRIC LARGE-SPAN ARCH SHEDS UNDER LOW-TEMPERATURE ENVIRONMENT

2020 ◽  
pp. 239-248
Author(s):  
Kai Zhou ◽  
Zhiwei Meng ◽  
Jialin Hou ◽  
Min Wei ◽  
Tianguo Jin ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Wind Speed ◽  
Low Temperature ◽  
Storage Capacity ◽  
Heat Storage ◽  
Large Span ◽  
Distribution Uniformity ◽  
Relationship Of ◽  
The Relationship ◽  
Better Than

In order to improve the effective sunshine time, heat storage capacity and temperature distribution uniformity of traditional arch shed under low temperature, this paper designed a large-span arch shed which has larger sunny side span and east-west orientation. According to the numerical and measured data, it is concluded that the heat storage capacity and temperature distribution of asymmetrical arch shed are better than those of symmetrical arch shed within a certain range of the ratio between sunny and shaded side. After that, ten different asymmetric arch sheds were designed. It is concluded that the structure of 11+9 m along north-south direction has the best heat storage capacity. Besides that, the analysis of outside wind speed and opening size of top vent were carried out. It is found that the outside wind and top vent can effectively promote convection and exchange of the air, and then achieve the purpose of reducing the temperature. At the end of this paper, in order to identify the relationship of temperature with the structure of arch shed, outside wind speed, and opening size of top vent, a mathematical model was built based on response surface methodology, which would provide theoretical guidance for the design of arch sheds.

Sign in / Sign up

Export Citation Format

Share Document