The Relationship of Low-Temperature Rheology to Engine Oil Pumpability

1973 ◽  
Author(s):  
Michael L. Mcmillan ◽  
Chester K. Murphy
Keyword(s):  
Low Temperature ◽  
Engine Oil ◽  
Relationship Of ◽  
The Relationship

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 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.

scholarly journals KONDO IMPURITY IN A DISORDERED METAL: ANDERSON'S THEOREM REVISITED

2000 ◽  
Vol 14 (14) ◽  
pp. 1421-1428 ◽  
Author(s):  
SUDIP CHAKRAVARTY ◽  
CHETAN NAYAK
Keyword(s):  
Low Temperature ◽  
Random Potential ◽  
Experimental Studies ◽  
Time Limit ◽  
Conduction Electrons ◽  
Large N ◽  
Long Time ◽  
Fluctuation Effects ◽  
Relationship Of ◽  
The Relationship

We consider a local moment which is coupled by a non-random Kondo J to a band of conduction electrons in a random potential. We prove an analog of Anderson's theorem in a large-N limit of this model. The theorem states that when the disorder is weak, the disorder-averaged low-temperature thermodynamics is independent of the strength of the disorder; remarkably, it further states that fluctuation effects in the long-time limit are independent even of the realization of the disorder. We discuss the relationship of this theorem to theoretical and experimental studies of similar problems.

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.

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