scholarly journals CHARACTERIZATION OF THE FROST HEAVE DEFORMATIONS IN HIGH LATITUDE AND DEEP SEASONALLY FROZEN SOIL OF INNER MONGOLIA WITH SENTINEL-1 INSAR OBSERVATIONS

2020 ◽  
Vol XLIII-B3-2020 ◽  
pp. 887-891
Author(s):  
T. Qu ◽  
H. Zhang ◽  
F. Niu ◽  
X. Shi ◽  
Z. Li
Keyword(s):  
Time Series ◽  
High Latitude ◽  
Inner Mongolia ◽  
Hydrothermal Process ◽  
Frozen Soil ◽  
In Situ Monitoring ◽  
Frost Heave ◽  
Permafrost Degradation

Abstract. Global warming in recent years led to significant permafrost degradation worldwide. Accurate monitoring and comprehensive characterization of the deformation process in seasonally frozen soil is of great importance for constructions in cold regions in China. This work concentrates on the deformation laws and spatio-temporal characteristics of frost heave in high latitude and seasonally frozen soil of Inner Mongolia with time series InSAR observations. With 101 Sentinel-1 descending scenes that covered more than three freeze-thaw cycles for the study area along Shiwei-Labudalin Highway, this study realized the characterization of the frost heave deformations in seasonally frozen soil, and the analysis of the influencing factors of the hydrothermal process with the help of temperature and moisture data from in-situ monitoring. Time series InSAR observations show that most parts of the highway show obvious deformation with a displacement rate of around 30–60 mm/yr. Especially, the deformation evolution in this seasonally frozen soil region changes with seasons, demonstrating a notable annual cyclical characteristic and seasonal activity. Moreover, time series in-situ monitoring data in deep underground boreholes not only further explains the deformation kinematics from InSAR observations, but also provide a better supplement for a more comprehensive mechanism understanding of frost heave deformations.

Photoreflectance Characterization of the Semi-Insulating InP Substrate Interface with InGaAs and InAlAs Epilayers

1992 ◽  
Vol 281 ◽  
Author(s):  
Weimin Zhou ◽  
H. Shen ◽  
J. Pamulapati ◽  
M. Dutta ◽  
B. R. Bennett ◽  
...  
Keyword(s):  
Electron Transition ◽  
In Situ Monitoring ◽  
Signal Phase ◽  
Mbe Growth ◽  
Substrate Interface ◽  
Inp Substrate ◽  
Excitonic Transition ◽  
Inp Substrates

ABSTRACTPhotoreflectance (PR) has been performed on a series of undoped and n-type, InGaAs and InAlAs molecular beam epitaxy (MBE) grown layers with different In mole fractions, and epilayer thicknesses on Fe-doped semi-insulating (SI)-InP substrates. From investigations of the temperature dependence, time constant dependence and an additional cw light beam intensity dependence, three substrate peaks are identified as an excitonic transition from the substrate, a free electron transition near the interface which gives a Franz-Keldysh oscillation (KFO), and a transition from the spin-orbit split-off valence band. The results are indicative of a redistribution of charge near the substrate interface in the process of MBE growth; the associated PR signal (phase) could be used for in-situ monitoring of epilayer growth on SI-InP wafers.

scholarly journals In situ monitoring of frost heave pressure during cross passage construction using ground-freezing method

2016 ◽  
Vol 53 (3) ◽  
pp. 530-539 ◽  
Author(s):  
Lei Han ◽  
Guan-lin Ye ◽  
Yuan-hai Li ◽  
Xiao-he Xia ◽  
Jian-hua Wang
Keyword(s):  
Pressure Gauge ◽  
Earth Pressure ◽  
In Situ Monitoring ◽  
Frost Heave ◽  
Freezing Process ◽  
Groundwater Levels ◽  
Freezing Method ◽  
Ground Freezing ◽  
Artificial Ground Freezing

The artificial ground-freezing method has the dual effect of ground reinforcement and waterproof sealing, and the frozen curtain can be designed flexibly. It is widely used in the construction of cross passages for shield tunnels in soft ground with high groundwater levels. However, due to the lack of in situ monitoring data, it remains difficult to determine the frost heave pressure acting upon a tunnel. In this study, based on the use of an anti-freezing pad-type earth pressure gauge, in situ monitoring was carried out to measure the frost heave pressure acting upon tunnel segments during the construction of cross passages for the Shanghai Yangtze River Tunnel. The monitoring results show that the earth pressure acting upon the tunnel could decrease dramatically during freezing, and this kind of decrease can take place suddenly and unpredictably, which can be illustrated using the finite element method. The maximum measured frost heave pressure during freezing and cross passage excavation was approximately 0.2 MPa, which was much smaller than the predicted value. Combining the distribution of temperature in the ground and construction countermeasures, the observed phenomena are mainly related to three factors: water migration during the freezing process, the tunnel–ground interaction, and the countermeasure of pressure release holes. The tunnel showed a horizontal extension–deformation, which was consistent with the releasing frost heave pressure acting upon it.

In situ monitoring of the growth and characterization of (PrMnO3)n(SrMnO3)n superlattices

2003 ◽  
Vol 94 (4) ◽  
pp. 2716-2724 ◽  
Author(s):  
B. Mercey ◽  
P. A. Salvador ◽  
Ph. Lecoeur ◽  
W. Prellier ◽  
M. Hervieu ◽  
...  
Keyword(s):  
In Situ Monitoring

Efficiency of Geosynthetic Lateral Drainage in Northern Climates

1996 ◽  
Vol 1534 (1) ◽  
pp. 12-18
Author(s):  
Jean Lafleur ◽  
Y. Savard
Keyword(s):  
Glacial Till ◽  
In Situ Monitoring ◽  
Frost Heave ◽  
Full Scale Test ◽  
Severe Damage ◽  
Flow Rates ◽  
Scale Test ◽  
Frost Penetration ◽  
Lateral Drainage

During winter the formation of ice lenses causes frost heave within frost-susceptible materials. The uneven spatial distribution of heave due to heterogeneity results in severe damage to the pavement. Fissures are created, favoring excess infiltration, especially during subsequent springtime thaw. The installation of drainage can be beneficial in reducing the amount of water present in road foundations. Some uncertainty, however, exists about the sources of water feeding the lenses and, therefore, the optimal location of the systems. To assess the efficiencies of deep lateral drainage systems, a full-scale test has been undertaken along an existing road constructed on a glacial till subgrade. Three 150-m-long vertical geocomposite systems were installed at depths ranging between 2 and 3 m. In situ monitoring included piezometers and frost indicators and measurements of flow rates and pavement heave. To obtain a point of comparison, the measurements started 1 year before drain installation. For the period of observation the freezing indexes ranged between 1432°C-day and 1558°C-day, and the maximum frost penetration was 2.5 m. The flow rates varied considerably with the seasons, ranging between 1 ml/sec/linear meter during winter and 10 ml/sec/m during the April thaw. Before drainage the heave values ranged between 50 and 150 mm. After installation they were reduced by a factor ranging between 10 and 50 percent.

A 50-Year Sr/Ca Time Series from an Enclosed, Shallow-Water Guam Coral: In situ Monitoring and Extraction of a Temperature Trend, Annual Cycle, and ENSO and PDO Signals

2019 ◽  
Vol 35 (2) ◽  
pp. 269
Author(s):  
Tomoko Bell ◽  
Mark A. Lander ◽  
John W. Jenson ◽  
Richard H. Randall ◽  
Judson W. Partin ◽  
...  
Keyword(s):  
Time Series ◽  
Shallow Water ◽  
Annual Cycle ◽  
Temperature Trend ◽  
In Situ Monitoring

Polarization Resolved Grazing Angle Scatterometry for In Situ Monitoring of Roughness for Silicon and Compound Solar Cells, Light Emitting Devices and other Structured Surfaces

MRS Advances ◽  
2017 ◽  
Vol 2 (53) ◽  
pp. 3129-3133
Author(s):  
Wojtek J. Walecki ◽  
Peter S. Walecki ◽  
Eve S. Walecki ◽  
Abigail S. Walecki
Keyword(s):  
Solar Cells ◽  
Grazing Angle ◽  
Stray Light ◽  
In Situ Monitoring ◽  
In Situ Characterization ◽  
Light Emitting ◽  
Structured Surfaces ◽  
Light Emitting Devices

ABSTRACTNovel metrology tool for in-situ characterization of surfaces semiconductor solar cells (both silicon and compound), and Light Emitting Device diffusers is presented. The tool measures the total integrated scattering when measuring forward, or back-reflection at very large angles of incidence. The tool is insensitive to vibrations and stray light. We discuss polarization resolved data and characterize our technique using NIST traceable standards. We discuss it’s applications to semiconductor manufacturing.

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