Infrared Photosensitivity Due to the Yb-Induced Defect States in Pb1−xGexTe Alloys

1999 ◽  
Vol 607 ◽  
Author(s):  
E.P. Skipetrov ◽  
N.A. Chernova ◽  
E.A. Zvereva ◽  
E.I. Slyn'ko
Keyword(s):  
Persistent Photoconductivity ◽  
Helium Temperature ◽  
Defect States ◽  
Galvanomagnetic Properties ◽  
Jahn Teller ◽  
Kinetics Of

AbstractGalvanomagnetic properties and photoconductivity kinetics of Pb1−xGexTe(x≤0.04) alloys doped with Yb have been investigated. The alloys exhibit high infrared photosensitivity at temperature under 40 K; at helium temperature, the effect of persistent photoconductivity has been observed. The photoconductivity kinetics after terminating of infrared illumination consists of a fast and a long-term relaxation regions. We explain the observed effects by a capture of electrons into the Yb-induced states, that are subjected to the Jahn-Teller instability. The parameters of the Jahn-Teller states are estimated.

Impurity-Induced Defect States in Pb1−xGexTe Alloys Doped With Gallium

1999 ◽  
Vol 607 ◽  
Author(s):  
E.P. Skipetrov ◽  
E.A. Zvereva ◽  
V.V. Belousov ◽  
L.A. Skipetrova
Keyword(s):  
Low Temperature ◽  
Heat Source ◽  
Single Crystals ◽  
Deep Level ◽  
Persistent Photoconductivity ◽  
Background Illumination ◽  
Defect States ◽  
Galvanomagnetic Properties ◽  
Controlled Illumination ◽  
Temperature Activation

AbstractGalvanomagnetic properties of n-Pb1−xGexTe<Ga>(O.04≤x≤O.08) single crystals have been investigated in the shielded from external background illumination chamber and under controlled illumination from infrared heat source. Low temperature activation range of the impurity conductivity on the dark curves of ρ(l/T) was revealed and attributed to the appearance of gallium-induced deep level EGa in the gap of the alloys. It was shown that the alloys possess high infrared photosensitivity at temperatures below Tc=50%60 K, and effect of the persistent photoconductivity at helium temperatures was revealed.

The Creation and Annealing Kinetics of Fast Light Induced Defect States created by 1 Sun Illumination in a-Si:H

2005 ◽  
Vol 862 ◽  
Author(s):  
M.L. Albert ◽  
J. Deng ◽  
X. Niu ◽  
J.M. Pearce ◽  
R.W. Collins ◽  
...  
Keyword(s):  
Defect States ◽  
Recombination Rates ◽  
Carrier Generation ◽  
Illumination Time ◽  
Overall Stability ◽  
History Of ◽  
Fast Light ◽  
Kinetics Of ◽  
Dispersive Process

AbstractPreliminary results are presented on the kinetics of fast states at 25°C created by 1 sun illumination in protocrystalline hydrogen diluted a-Si:H films. The results are for the bulk properties of the a-Si:H films which was confirmed by the similarity of results obtained on corresponding intrinsic layers in p-i-n solar cells. It is found that the kinetics exhibit two regimes. The first regime is in the form of a delay before the onset of an A·log(t) time dependence indicative of a dispersive process. Despite the unexpected effect of a dependence of this first regime on the degradation/annealing history of the samples, it was possible to characterize the highly reproducible logarithmic dependences for different illumination times as well as in the presence of different carrier generation/recombination rates. It is found that for the degradation times studied, the annealing kinetics associated with the second regime are independent of the 1 sun illumination time but are dependent on the recombination introduced by illuminations as low as ∼0-5 of 1 sun. These fast states are located close to midgap, similar to the position of dangling bond defects. The results presented raise interesting questions that still need to be answered about the nature and origin of the fast defects in order to assess their contribution to the long term degradation and the overall stability a-Si:H materials.

Comparative Labelling and Biokinetic Studies of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn)

1977 ◽  
Vol 16 (01) ◽  
pp. 30-35 ◽  
Author(s):  
N. Agha ◽  
R. B. R. Persson
Keyword(s):  
Complex Formation ◽  
Significant Influence ◽  
Room Temperature ◽  
Ph Value ◽  
Maximum Activity ◽  
Reduction Step ◽  
Labelling Yield ◽  
Different Temperatures ◽  
Kinetics Of

SummaryGelchromatography column scanning has been used to study the fractions of 99mTc-pertechnetate, 99mTcchelate and reduced hydrolyzed 99mTc in preparations of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn). The labelling yield of 99mTc-EDTA(Sn) chelate was as high as 90—95% when 100 μmol EDTA · H4 and 0.5 (Amol SnCl2 was incubated with 10 ml 99mTceluate for 30—60 min at room temperature. The study of the influence of the pH-value on the fraction of 99mTc-EDTA shows that pH 2.8—2.9 gave the best labelling yield. In a comparative study of the labelling kinetics of 99mTc-EDTA(Sn) and 99mTc- DTPA(Sn) at different temperatures (7, 22 and 37°C), no significant influence on the reduction step was found. The rate constant for complex formation, however, increased more rapidly with increased temperature for 99mTc-DTPA(Sn). At room temperature only a few minutes was required to achieve a high labelling yield with 99mTc-DTPA(Sn) whereas about 60 min was required for 99mTc-EDTA(Sn). Comparative biokinetic studies in rabbits showed that the maximum activity in kidneys is achieved after 12 min with 99mTc-EDTA(Sn) but already after 6 min with 99mTc-DTPA(Sn). The long-term disappearance of 99mTc-DTPA(Sn) from the kidneys is about five times faster than that for 99mTc-EDTA(Sn).

Persistent Photoconductivity And Thermal Recovery Kinetics Of Low Energy Ar + Bombarded GaAs

1991 ◽  
Vol 223 ◽  
Author(s):  
A. Vaseashta ◽  
L. C. Burton
Keyword(s):  
Deep Level Transient Spectroscopy ◽  
Deep Level ◽  
Thermal Recovery ◽  
Low Energy ◽  
Persistent Photoconductivity ◽  
Transport Parameters ◽  
Excellent Correlation ◽  
Proposed Model ◽  
Transient Spectroscopy ◽  
Kinetics Of

ABSTRACTKinetics of persistent photoconductivity, photoquenching, and thermal and optical recovery observed in low energy Ar+ bombarded on (100) GaAs surfaces have been investigated. Rate and transport equations for these processes were derived and simulated employing transport parameters, trap locations and densities determined by deep level transient spectroscopy. Excellent correlation was obtained between the results of preliminary simulation and the experimentally observed values. The exponential decay of persistent photoconductivity response curve was determined to be due to metastable electron traps with longer lifetime and is consistent with an earlier proposed model.

scholarly journals Automated Microscopy: Macro Language Controlling a Confocal Microscope and its External Illumination: Adaptation for Photosynthetic Organisms

2016 ◽  
Vol 22 (2) ◽  
pp. 258-263 ◽  
Author(s):  
Gábor Steinbach ◽  
Radek Kaňa
Keyword(s):  
Light Sources ◽  
Light Conditions ◽  
Photosynthetic Organisms ◽  
Automated Microscopy ◽  
Photosynthetic Microorganisms ◽  
Arduino Microcontroller ◽  
Microscopy Data ◽  
Kinetics Of ◽  
Photosynthetic Cells

AbstractPhotosynthesis research employs several biophysical methods, including the detection of fluorescence. Even though fluorescence is a key method to detect photosynthetic efficiency, it has not been applied/adapted to single-cell confocal microscopy measurements to examine photosynthetic microorganisms. Experiments with photosynthetic cells may require automation to perform a large number of measurements with different parameters, especially concerning light conditions. However, commercial microscopes support custom protocols (throughTime Controlleroffered by Olympus orExperiment Designeroffered by Zeiss) that are often unable to provide special set-ups and connection to external devices (e.g., for irradiation). Our new system combining an Arduino microcontroller with theCell⊕Findersoftware was developed for controlling Olympus FV1000 and FV1200 confocal microscopes and the attached hardware modules. Our software/hardware solution offers (1) a text file-based macro language to control the imaging functions of the microscope; (2) programmable control of several external hardware devices (light sources, thermal controllers, actuators) during imaging via the Arduino microcontroller; (3) theCell⊕Findersoftware with ergonomic user environment, a fast selection method for the biologically important cells and precise positioning feature that reduces unwanted bleaching of the cells by the scanning laser.Cell⊕Findercan be downloaded fromhttp://www.alga.cz/cellfinder. The system was applied to study changes in fluorescence intensity inSynechocystissp. PCC6803 cells under long-term illumination. Thus, we were able to describe the kinetics of phycobilisome decoupling. Microscopy data showed that phycobilisome decoupling appears slowly after long-term (>1 h) exposure to high light.

Long-Term Clinical Effects, Bioavailability, and Kinetics of Minoxidil in Relation to Renal Function

1978 ◽  
Vol 18 (10) ◽  
pp. 500-508 ◽  
Author(s):  
DAVID T. LOWENTHAL ◽  
GADDO ONESTI ◽  
ROBERT MUTTERPERL ◽  
MELTON APFRIME ◽  
EDUARDO W. MARTINEZ ◽  
...  
Keyword(s):  
Renal Function ◽  
Clinical Effects ◽  
Kinetics Of

Phosphorus removal by apatite in horizontal flow constructed wetlands for small communities: pilot and full-scale evidence

2011 ◽  
Vol 63 (8) ◽  
pp. 1629-1637 ◽  
Author(s):  
N. Harouiya ◽  
S. Martin Rue ◽  
S. Prost-Boucle ◽  
A. Liénar ◽  
D. Esser ◽  
...  
Keyword(s):  
Constructed Wetlands ◽  
Particle Surface ◽  
Full Scale ◽  
Retention Capacity ◽  
Small Communities ◽  
Lab Experiments ◽  
Apatite Mineral ◽  
Kinetics Of ◽  
P Removal

Phosphorus (P) removals in constructed wetlands (CWs) have received particular attention in recent decades by using specific materials which promote adsorption/precipitation mechanisms. Recent studies have shown interest in using apatite materials to promote P precipitation onto the particle surface. As previous trials were mainly done by lab experiments, this present study aims to evaluate the real potential of apatites to remove P from wastewater in pilot units and a full-scale plant over a 2 year period. P retention kinetics of two qualities of apatites are presented and discussed. In this work apatite appears to have high retention capacity (&gt;80% of P removal) and is still an interesting way for P removal in CWs for limiting the risk of eutrophication downstream of small communities. Nevertheless, the apatite quality appears to be of great importance for a reliable and long term P removal. The use of materials with low content of apatite mineral (40–50%) seems to be not economically relevant.

Long‐term desorption kinetics of Cu2+from biosorbent in water and seawater

2001 ◽  
Vol 79 (1-2) ◽  
pp. 117-125
Author(s):  
Qiming Yu ◽  
Pairat Kaewsarn ◽  
Weidong Ma
Keyword(s):  
Desorption Kinetics ◽  
Kinetics Of
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