Semicontinuous Measurement of Soil Atmosphere Gases with Gas-Flow Soil Core Method

1995 ◽  
Vol 59 (5) ◽  
pp. 1336-1342 ◽  
Author(s):  
M. Swerts ◽  
G. Uytterhoeven ◽  
R. Merckx ◽  
K. Vlassak
1984 ◽  
Vol 16 (4) ◽  
pp. 323-330 ◽  
Author(s):  
Timothy B. Parkin ◽  
Heinrich F. Kaspar ◽  
Alan J. Sexstone ◽  
James M. Tiedje
Keyword(s):  
Gas Flow ◽  

2019 ◽  
Vol 105 ◽  
pp. 316-328 ◽  
Author(s):  
Weiwei Chen ◽  
Xunhua Zheng ◽  
Benjamin Wolf ◽  
Zhisheng Yao ◽  
Chunyan Liu ◽  
...  

2011 ◽  
Vol 45 (14) ◽  
pp. 6066-6072 ◽  
Author(s):  
Rui Wang ◽  
Georg Willibald ◽  
Qi Feng ◽  
Xunhua Zheng ◽  
Tingting Liao ◽  
...  
Keyword(s):  
Gas Flow ◽  

Chemosphere ◽  
2013 ◽  
Vol 93 (11) ◽  
pp. 2848-2853 ◽  
Author(s):  
Tingting Liao ◽  
Rui Wang ◽  
Xunhua Zheng ◽  
Yang Sun ◽  
Klaus Butterbach-Bahl ◽  
...  

2012 ◽  
Vol 46 (1) ◽  
pp. e-33-e-35 ◽  
Author(s):  
H. Bharti ◽  
A. Wachkoo

First Record of the Genus Myopias (Hymenoptera, Formicidae) from India, with Description of New Species Myopias shivalikensis Bharti et Wachkoo, sp. n. is described based on a single worker, collected in lower Shivalik range (700 m a. s. l.) of Northwest Himalaya by soil core method. The genus Myopias is recorded for the first time in India. M. shivalikensis is a cryptobiotic species with reduced body size and rudimentary eyes. It is similar to M. nops Willey et Brown, 1983, distinctly differing from all described species of this genus.


2014 ◽  
Vol 11 (6) ◽  
pp. 8399-8442 ◽  
Author(s):  
C. Werner ◽  
K. Reiser ◽  
M. Dannenmann ◽  
L. B. Hutley ◽  
J. Jacobeit ◽  
...  

Abstract. Strong seasonal variability of hygric and thermal soil conditions are a defining environmental feature in Northern Australia. However, how such changes affect the soil–atmosphere exchange of nitrous oxide (N2O), nitric oxide (NO) and dinitrogen (N2) is still not well explored. By incubating intact soil cores from four sites (3 savanna, 1 pasture) under controlled soil temperatures (ST) and soil moisture (SM) we investigated the release of the trace gas fluxes of N2O, NO and carbon dioxide (CO2). Furthermore, the release of N2 due to denitrification was measured using the helium gas flow soil core technique. Under dry pre-incubation conditions NO and N2O emission were very low (<7.0 ± 5.0 μg NO-N m−2 h−1; <0.0 ± 1.4 μg N2O-N m−2 h−1) or in case of N2O, even a net soil uptake was observed. Substantial NO (max: 306.5 μg N m−2 h−1) and relatively small N2O pulse emissions (max: 5.8 ± 5.0 μg N m−2 h−1) were recorded following soil wetting, but these pulses were short-lived, lasting only up to 3 days. The total atmospheric loss of nitrogen was dominated by N2 emissions (82.4–99.3% of total N lost), although NO emissions contributed almost 43.2% at 50% SM and 30 °C ST. N2O emissions were systematically higher for 3 of 12 sample locations, which indicates substantial spatial variability at site level, but on average soils acted as weak N2O sources or even sinks. Emissions were controlled by SM and ST for N2O and CO2, ST and pH for NO, and SM and pH for N2.


Soil Science ◽  
1997 ◽  
Vol 162 (7) ◽  
pp. 510-517 ◽  
Author(s):  
D. R. Shelton ◽  
A. M. Sadeghi ◽  
G. W. McCarty ◽  
A. R. Isensee

Author(s):  
N. David Theodore ◽  
Mamoru Tomozane ◽  
Ming Liaw

There is extensive interest in SiGe for use in heterojunction bipolar transistors. SiGe/Si superlattices are also of interest because of their potential for use in infrared detectors and field-effect transistors. The processing required for these materials is quite compatible with existing silicon technology. However, before SiGe can be used extensively for devices, there is a need to understand and then control the origin and behavior of defects in the materials. The present study was aimed at investigating the structural quality of, and the behavior of defects in, graded SiGe layers grown by chemical vapor deposition (CVD).The structures investigated in this study consisted of Si1-xGex[x=0.16]/Si1-xGex[x= 0.14, 0.13, 0.12, 0.10, 0.09, 0.07, 0.05, 0.04, 0.005, 0]/epi-Si/substrate heterolayers grown by CVD. The Si1-xGex layers were isochronally grown [t = 0.4 minutes per layer], with gas-flow rates being adjusted to control composition. Cross-section TEM specimens were prepared in the 110 geometry. These were then analyzed using two-beam bright-field, dark-field and weak-beam images. A JEOL JEM 200CX transmission electron microscope was used, operating at 200 kV.


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