The Selective Epitaxy of Silicon at Low Temperatures

ABSTRACTLow-temperature selective epitaxial growth (SEG) of silicon using a dichlorosilane-hydrogen mixture in an LPCVD hot-wall reactor has been discussed with respect to the wafer preparation and the deposition cycle. The surface morphology and the quality of epilayers are strongly affected by residual oxide islands at interface. A reduction of local growth rate near interfacial oxides is attributed to the dissolution of oxide at interface, and this reduction can lead to pits and textured features on the Si epitaxial surface. An ex-situ HF vapor or an HF dip with an in-situ small DCS 900°C prebake step can completely remove surface oxide prior to the deposition and achieve defect-free Si epilayers at the deposition temperatures of 850°C and 800°C. It is also found that fluorine atoms can play a major role in the removal of surface oxide.

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Low Temperature Diamond Growth With CF4 Addition in A Hot Filament Reactor

MRS Proceedings ◽

10.1557/proc-349-421 ◽

1994 ◽

Vol 349 ◽

Cited By ~ 3

Author(s):

Evaldo. J. Corat ◽

V. J. Trava-Airoldi ◽

Nélia F. Leite ◽

Angel F.V. Peña ◽

Vítor Baranauskas

Keyword(s):

Growth Rate ◽

Raman Spectroscopy ◽

Low Temperature ◽

Substrate Temperature ◽

Low Temperatures ◽

Diamond Growth ◽

Gas Mixture ◽

Hot Filament ◽

Micro Balance

ABSTRACTIn this work we show that the addition of a small amount of CF4 to a regular CH4 -H2 gas mixture allows diamond growth at lower temperatures with reasonable growth rates. We used a hot filament assisted reactor and observed diamond growth with a substrate temperature as low as 390 ଌ. We present a comparative study for the growth dependence on substrate temperature with and without CF4 addition in the gas mixture. The growth rate is measured by post growth weighting with a micro balance. Raman spectroscopy, SEM and AFM images show the good quality of the films grown at low temperatures when CF4 is added to the feeding gas.

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In situ Tensile Experiments at Low Temperatures on Niobium Single Crystals by H.V.E.M.

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100113913 ◽

1975 ◽

Vol 33 ◽

pp. 58-59

Author(s):

F. H. Louchet ◽

L. P. Kubin

Keyword(s):

Electron Microscope ◽

Transition Temperature ◽

Low Temperature ◽

Slip System ◽

Low Temperatures ◽

Tensile Axis ◽

Image Intensifier ◽

Screw Dislocations ◽

Source Operation

Experiments have been carried out on the 3 MeV electron microscope in Toulouse. The low temperature straining holder has been previously described Images given by an image intensifier are recorded on magnetic tape.The microtensile niobium samples are cut in a plane with the two operative slip directions [111] and lying in the foil plane. The tensile axis is near [011].Our results concern:- The transition temperature of niobium near 220 K: at this temperature and below an increasing difference appears between the mobilities of the screw and edge portions of dislocations loops. Source operation and interactions between screw dislocations of different slip system have been recorded.

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Start-up Strategies for Anaerobic Ammonia Oxidation (Anammox) in In-Situ Nitrogen Removal from Polluted Groundwater in Rare Earth Mining Areas

Sustainability ◽

10.3390/su13084591 ◽

2021 ◽

Vol 13 (8) ◽

pp. 4591

Author(s):

Shuanglei Huang ◽

Daishe Wu

Keyword(s):

Rare Earth ◽

Low Temperature ◽

Removal Efficiency ◽

Nitrogen Removal ◽

Ex Situ ◽

High Concentration ◽

Low Concentration ◽

Start Up ◽

Anammox Activity

The tremendous input of ammonium and rare earth element (REE) ions released by the enormous consumption of (NH4)2SO4 in in situ leaching for ion-adsorption RE mining caused serious ground and surface water contamination. Anaerobic ammonium oxidation (anammox) was a sustainable in situ technology that can reduce this nitrogen pollution. In this research, in situ, semi in situ, and ex situ method of inoculation that included low-concentration (0.02 mg·L−1) and high-concentration (0.10 mg·L−1) lanthanum (La)(III) were adopted to explore effective start-up strategies for starting up anammox reactors seeded with activated sludge and anammox sludge. The reactors were refrigerated for 30 days at 4 °C to investigate the effects of La(III) during a period of low-temperature. The results showed that the in situ and semi in situ enrichment strategies with the addition of La(III) at a low-concentration La(III) addition (0.02 mg·L−1) reduced the length of time required to reactivate the sludge until it reached a state of stable anammox activity and high nitrogen removal efficiency by 60–71 days. The addition of La(III) promoted the formation of sludge floc with a compact structure that enabled it to resist the adverse effects of low temperature and so to maintain a high abundance of AnAOB and microbacterial community diversity of sludge during refrigeration period. The addition of La(III) at a high concentration caused the cellular percentage of AnAOB to decrease from 54.60 ± 6.19% to 17.35 ± 6.69% during the enrichment and reduced nitrogen removal efficiency to an unrecoverable level to post-refrigeration.

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In situ UV monitoring of wastewater: a response to sample aging

Water Science & Technology ◽

10.2166/wst.2004.0015 ◽

2004 ◽

Vol 49 (1) ◽

pp. 47-52 ◽

Cited By ~ 3

Author(s):

E. Baurès ◽

C. Berho ◽

M.-F. Pouet ◽

O. Thomas

Keyword(s):

Low Temperature ◽

Process Control ◽

Treated Wastewater ◽

Wastewater Sample ◽

Line Measurement ◽

Regulation Compliance

The phenomenon of wastewater sample aging is supposed to be treated with a low temperature autosampler. This work presents two examples of treated wastewater, the quality of which varies with the time of conservation. This evolution may pose some problems with respect to regulation compliance or process control. After the explanation of the mechanisms involved in sample aging, some recommendations are proposed in order to improve the UV off-line measurement of TSS and COD of treated wastewater.

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Longevity of seeds and soil seed bank of the Cerrado tree Miconia chartacea (Melastomataceae)

Seed Science Research ◽

10.1017/s0960258515000173 ◽

2015 ◽

Vol 25 (4) ◽

pp. 386-394 ◽

Cited By ~ 3

Author(s):

Diego F. Escobar E. ◽

Victor J. M. Cardoso

Keyword(s):

Seed Bank ◽

Low Temperatures ◽

Rainy Season ◽

Storage Time ◽

Soil Seed Bank ◽

High Water ◽

Ex Situ ◽

High Water Content ◽

Storage Test

AbstractMiconia chartacea is a widely distributed tree in Brazil, occurring at altitudes ranging from 300 m to 1900 m in the Caatinga, Cerrado and Atlantic Forest biomes. In this work we attempted to classify M. chartacea seeds regarding their behaviour during storage and their germination syndrome and to determine, from a storage test in Cerrado soil and laboratory conditions in situ and ex situ, the longevity of seeds, as well as the capacity of the species to form a soil seed bank. The results suggested that M. chartacea seeds form a transient soil seed bank in the Cerrado and can be classified as orthodox in terms of storage behaviour, although the seeds are dispersed with a relatively high water content. The life span of seeds was favoured in soil-stored seeds in comparison with dry storage at 25°C, whereas storage at low temperatures prevented a decrease of the seed's germinability with storage time (330 d). M. chartacea seeds are dispersed during the dry season and germinate during the next rainy season, which can be classified as an intermediate–dry germination syndrome. Seeds of this species are dispersed in the Cerrado when temperatures and soil moisture are relatively low, which favours the formation of a soil seed bank, considering that the seeds tolerate desiccation and their longevity is favoured by low temperatures. A transient seed bank type is favoured by the loss of viability in storage at warm temperatures linked to the rainy season, and the predictable seasonal variations in climate in the region, with germination being restricted to the beginning of the rainy season.

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In-situ and ex-situ characterization of surface oxide films on AB5-type metal hydride electrodes

Journal of Alloys and Compounds ◽

10.1016/s0925-8388(99)00350-3 ◽

1999 ◽

Vol 293-295 ◽

pp. 747-750 ◽

Cited By ~ 5

Author(s):

J.M Nan ◽

Y Yang ◽

J.K You ◽

X.Q Li ◽

Z.G Lin

Keyword(s):

Metal Hydride ◽

Oxide Films ◽

Surface Oxide ◽

Ex Situ ◽

Metal Hydride Electrodes

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(Keynote) Recent Progress in Nanoscale Understanding of Surface Oxide Film Formation, Properties and Breakdown on Metals and Alloys Using in Situ and Ex Situ Characterization Methods

ECS Meeting Abstracts ◽

10.1149/ma2016-02/10/1143 ◽

2016 ◽

Keyword(s):

Oxide Film ◽

Recent Progress ◽

Film Formation ◽

Metals And Alloys ◽

Surface Oxide ◽

Ex Situ ◽

Surface Oxide Film ◽

Characterization Methods

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Electrochemical generation of 2,3-oxazolidinone glycosyl triflates as an intermediate for stereoselective glycosylation

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.8.52 ◽

2012 ◽

Vol 8 ◽

pp. 456-460 ◽

Cited By ~ 22

Author(s):

Toshiki Nokami ◽

Akito Shibuya ◽

Yoshihiro Saigusa ◽

Shino Manabe ◽

Yukishige Ito ◽

...

Keyword(s):

Low Temperature ◽

Electrochemical Oxidation ◽

Low Temperatures ◽

Protecting Group ◽

Triflic Acid ◽

Electrochemical Generation ◽

Stereoselective Glycosylation

Glycosyl triflates with a 2,3-oxazolidinone protecting group were generated from thioglycosides by low-temperature electrochemical oxidation. The glycosyl triflates reacted with alcohols to give the corresponding glycosides β-selectively at low temperatures. However, α-selectivity was observed in the absence of base at elevated reaction temperatures. In situ generated triflic acid promotes the isomerization of β-products to α-products.

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The SCOC database, a large, open, and global database with sediment community oxygen consumption rates

Scientific Data ◽

10.1038/s41597-019-0259-3 ◽

2019 ◽

Vol 6 (1) ◽

Cited By ~ 2

Author(s):

Tanja Stratmann ◽

Karline Soetaert ◽

Chih-Lin Wei ◽

Yu-Shih Lin ◽

Dick van Oevelen

Keyword(s):

Oxygen Consumption ◽

Oxygen Uptake ◽

Selection Procedure ◽

Ex Situ ◽

Global Database ◽

Data Record ◽

Consumption Rates ◽

Meta Analyses

Abstract Sediment community oxygen consumption (SCOC) rates provide important information about biogeochemical processes in marine sediments and the activity of benthic microorganisms and fauna. Therefore, several databases of SCOC data have been compiled since the mid-1990s. However, these earlier databases contained much less data records and were not freely available. Additionally, the databases were not transparent in their selection procedure, so that other researchers could not assess the quality of the data. Here, we present the largest, best documented, and freely available database of SCOC data compiled to date. The database is comprised of 3,540 georeferenced SCOC records from 230 studies that were selected following the procedure for systematic reviews and meta-analyses. Each data record states whether the oxygen consumption was measured ex situ or in situ, as total oxygen uptake, diffusive or advective oxygen uptake, and which measurement device was used. The database will be curated and updated annually to secure and maintain an up-to-date global database of SCOC data.

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