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Resistivity Values (resistivity + value)
Selected AbstractsGrowth of lead bromide polycrystalline filmsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 10 2004M. Giles Abstract Lead bromide polycrystalline films were grown by the physical vapor deposition method (PVD). Glass 1,x1, in size, uncoated, and coated with Indium Tin Oxide (ITO), was used as substrate and rear contact. The starting material was evaporated at temperatures from 395°C to 530°C under high vacuum atmosphere (6 x 10 -3 Pa) and during 8 days. The substrate temperature was prefixed from 190°C to 220°C. Film thickness yielded values from 40 to 90 ,m. Optical microscopy and scanning electron microscopy (SEM) were performed on the films. Grain size resulted to be from 1.0 to 3.5 ,m. SEM and X-ray diffraction indicate that films grow with a preferred orientation with the (0 0 l) planes parallel to the substrate. The Texture Coefficient (TC) related to the plane (0 0 6) was 7.3. Resistivity values in the order of 1012 ,cm were obtained for the oriented samples, but a strong polarization indicates severe charge transport problems in the films. Film properties were correlated with the growth temperature and with previous results for films of other halides. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Evidence of nanodomes in carbon nitride thin filmsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 2 2004S. Chowdhury Abstract This article reports the synthesis of hard and conductive carbon nitride thin films with evidence of formation of nanodomes over a range of substrate temperature from 50 °C to 550 °C. The size of the nanodomes increases from 40,80 nm at room temperature to 200,400 nm at high temperature (550 °C). Electrical characterization shows that these films have conductive behaviour with a resistivity depending on the size of the nanodomes. Resistivity values of 19 m, cm were found for nanodomes of size 40,80 nm falling to 6 m, cm for nanodomes of size 200,400 nm. Nanoindentation results show that the hardness and Young's modulus of these films are in the range from 9,22 GPa and 100,168 GPa respectively and these values decrease as the size of the nanodomes increases. GXRD results confirm that a crystalline graphitic carbon nitride structure has formed. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Monitoring Lung Resistivity Changes in Congestive Heart Failure Patients Using the Bioimpedance TechniqueCONGESTIVE HEART FAILURE, Issue 6 2005Sharon Zlochiver MSc The feasibility of a novel, dedicated system for monitoring lung resistivity in congestive heart failure patients, implementing a hybrid approach of the bioimpedance technique, was assessed in this preliminary study. Thirty-three healthy volunteers and 34 congestive heart failure patients were measured with the PulmoTrace system (Cardiolnspect, Tel Aviv University, Tel Aviv, Israel) during tidal respiration, and the ability to monitor the respective lung resistivity values was assessed. Mean left and right lung resistivity values of 1205±163 and 1200±165 ,·cm for the control group and 888±193 and 943±187 ,·cm for the congestive heart failure group were found, indicating a significant (p<2·10,7) difference between the two groups. The results of long-term monitoring of two patients during medical treatment are also shown. This hybrid approach system is believed to improve diagnostic capabilities and help physicians to better adjust medication dosage on a frequent basis. [source] Integrated deep drilling, coring, downhole logging, and data management in the Chicxulub Scientific Drilling Project (CSDP), MexicoMETEORITICS & PLANETARY SCIENCE, Issue 6 2004Lothar Wohlgemuth To date, a continuous scientific sampling of large impact craters from cover rocks to target material has only seldom been performed. The first project to deep-drill and core into one of the largest and well-preserved terrestrial impact structures was executed in the winter of 2001/2002 in the 65 Myr-old Chicxulub crater in Mexico using integrated coring sampling and in situ measurements. The combined use of different techniques allows a three-dimensional insight and a better understanding of impact processes. Here, we report the integration of conventional rotary drilling techniques with wireline mining coring technology that was applied to drill the 1510 m-deep Yaxcopoil-1 (Yax-1) well about 40 km southwest of Mérida, Yucatán, Mexico. During the course of the project, we recovered approximately 900 m of intact core samples including the transitions of reworked ejecta to post-impact sediments, and that one from large blocks of tilted target material to impact-generated rocks, i.e., impact melt breccias and suevites. Coring was complemented by wireline geophysical measurements to obtain a continuous set of in situ petrophysical data of the borehole walls. The data acquired is comprised of contents of a natural radioactive element, velocities of compressional sonic waves, and electrical resistivity values. All the digital data sets, including technical drilling parameters, initial scientific sample descriptions, and 360° core pictures, were distributed during the course of the operations via Internet and were stored in the ICDP Drilling Information System (http:www.icdp-online.org), serving the global community of cooperating scientists as a basic information service. [source] Applicability of electrical resistivity tomography monitoring to coarse blocky and ice-rich permafrost landformsPERMAFROST AND PERIGLACIAL PROCESSES, Issue 3 2009C. Hilbich Abstract The inversion and interpretation of electrical resistivity tomography (ERT) data from coarse blocky and ice-rich permafrost sites are challenging due to strong resistivity contrasts and high contact resistances. To assess temporal changes during ERT monitoring (ERTM), corresponding inversion artefacts have to be separated from true subsurface changes. Appraisal techniques serve to analyse an ERTM data set from a rockglacier, including synthetic modelling, the depth of investigation index technique and the so-called resolution matrix approach. The application of these methods led step by step to the identification of unreliable model regions and thus to the improvement in interpretation of temporal resistivity changes. An important result is that resistivity values of model regions with strong resistivity contrasts and highly resistive features are generally of critical reliability, and resistivity changes within or below the ice core of a rockglacier should therefore not be interpreted as a permafrost signal. Conversely, long-term degradation phenomena in terms of warming of massive ground ice at the permafrost table are detectable by ERTM. Copyright © 2009 John Wiley & Sons, Ltd. [source] Genetic differences of rock glaciers and the discontinuous mountain permafrost zone in Kanchanjunga Himal, Eastern NepalPERMAFROST AND PERIGLACIAL PROCESSES, Issue 3 2001Mamoru Ishikawa Abstract A number of rock glaciers, including glacier-derived and talus-derived rock glaciers, were identified in Kanchanjunga Himal, easternmost Nepal. DC resistivity imagings were applied to representative rock glaciers of both types. The distribution of resistivity values in the subsurface within these rock glaciers was significantly different. A massive glacial ice body was found within the glacier-derived rock glacier, suggesting this rock glacier originated from glacial dead ice (ice-cored rock glacier). The lower limits of discontinuous mountain permafrost zone in Kanchanjunga Himal were inferred from the distribution of talus-derived rock glaciers (ice-cemented rock glaciers) and the estimated mean annual air temperature. The lower limit of the discontinuous mountain permafrost zone is 4800 m ASL on the north-facing slopes, while 5300 m ASL on the south- to east-facing slopes. These altitudes were considerably higher than those of the western Himalaya, which are under dry continental climatic conditions. Copyright © 2001 John Wiley & Sons, Ltd. RÉSUMÉ Plusieurs glaciers rocheux comprenant à la fois des formes dérivéees de vrais glaciers et des formes provenant de la mise en mouvement de talus, ont été identifiés dans le Kanchanjunga Himal, dans le Népal le plus oriental. Des images par résistivité DC ont été obtenues pour des glaciers représentatifs des deux catégories. La distribution des valeurs de résistivité en profondeur dans ces glaciers rocheux a été significativement différente. Un corps de glace massif a été trouvé dans le glacier rocheux provenant d'un vrai glacier suggérant qu'il s'agissait de glace morte glaciaire (glacier rocheux à noyau de glace). Les limites inférieures de la zone du pergélisol discontinu dans le Kanchanjungga Himal ont été déduites de la distribution des glaciers rocheux provenant de talus (glaciers rocheux avec de la glace ciment) et d'une estimation de la température moyenne annuelle de l'air. La limite inférieure de la zone du pergélisol discontinu de montagne est de 4800 m d'altitude sur les pentes exposées au nord, tandis que la limite est de 5300 m sur les pentes exposées au sud. Ces altitudes sont considérablement plus élevées que celles de l'ouest de l'Himalaya exposé à des conditions climatiques continentales sèches. Copyright © 2001 John Wiley & Sons, Ltd. [source] Optical and transport properties of Ti-doped In2O3 thin films prepared by electron beam physical vapour depositionPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 7 2010J. Sánchez-Marcos Abstract Ti-doped In2O3 (ITiO) thin films have been prepared by electron beam physical vapour deposition (EB-PVD). Their optical and electrical properties are studied for the obtained compositions. After oxygen annealing all samples show excellent optical transparence; additionally, maximum values for conductivity are obtained for samples with titanium contents near 6,at.%, with typical resistivity values of 4,×,10,5,,,cm. Finally, the band-gap energy evolution is studied for the set of samples. [source] Nondestructive topographic resistivity evaluation of semi-insulating SiC substratesPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 3 2003R. Stibal Abstract Semi-insulating silicon carbide single crystals have been grown using high temperature chemical vapor deposition without vanadium doping. The resistivity of standard and exploratory 2, diameter substrates has been analysed topographically with 1 mm lateral resolution with an improved contactless resistivity mapping technique. Absolute resistivity values are ranging from below 1 × 105 to above 1 × 1012 , cm. The lateral homogeneity of state-of-the-art material is very satisfactory, whereas strong localized inhomogeneities in exploratory materials underscore the decisive advantage of a nondestructive and topographic resistivity evaluation in supporting the optimization of the crystal growth procedure. [source] Electrical properties of structured HIPS/gamma-irradiated UHMWPE/carbon black blendsPOLYMER ENGINEERING & SCIENCE, Issue 4 2000O. Breuer HIPS/UHMWPE and HIPS/XL-UHMWPE containing carbon black (CB) are unique systems in which CB is attracted to the PE, and thus structuring takes place affecting the morphology and the resultant electrical properties. UHMWPE, having a very high viscosity, was chosen as the dispersed phase within HIPS in place of a conventional polymer in order to explore possibilities of obtaining unique structures that would induce the CB to segregate and form a conductive network. XL-UHMWPE particles also constitute an interesting dispersed phase, maintaming their highly porous and intricate structure even subsequent to melt processing. In both cases the CB is located at the interface; however, differences in resistivity values are observed. When low UHMWPE or XL-UHMWPE contents are incorporated, the HIPS/XL-UHMWPE/CB compositions have lower resistivities due to the heterogeneity of the interface, even at high shear rates. When high UHMWPE or XL-UHMWPE contents are utilized, the trends reverse: HIPS/UHMWPE/CB depict enhanced conductivity, due to the dominance of UHMWPE particle coalescence and the resultant decrease in surface area. This is contrary to what happens with the XL-UHMWPE particles, where the surface area increases with their higher contents, since they do not coalesce. [source] Contribution of geophysics to outlining the foundation structure of the Islamic Museum, Cairo, EgyptARCHAEOLOGICAL PROSPECTION, Issue 3 2005A. M. Abbas Abstract The Islamic museum was erected in 1896. The building is situated in the heart of Cairo (capital of Egypt) and holds marvellous Islamic antiquities and priceless ancient hand-writing and rare books. Recently, a restoration scheme has been planned to secure the old building which suffers from weakened foundations. In addition, the wooden roofs will be replaced by concrete ones and an extra floor will be integrated into the building. Unfortunately, the architecture construction charts were neither available nor obtainable. Therefore, the structure of the foundations and the base walls of the building had to be outlined. At the time of construction, three major fundamental wall designs were dominant and were to be considered during the work approach. Ground-penetrating radar (GPR) and dipole,dipole resistivity imaging have been integrated to (define the structure of the foundation walls of the building. A Ramac2 system connected to a 500,MHz antenna has been utilized for conducting the GPR survey. In addition, a Terrameter SAS 1000 single channel device has been used for performing the resistivity profiles. At accessible spaces around the building GPR and resistivity profiles were obtained. The GPR analysis has revealed the depth of the foundation walls to be about 0.9,m from the ground surface with a width close to 0.6,m. The wall design is close to a straight wall style. Furthermore, the analysis of the dipole,dipole resistivity measurements has matched the geology of the area, where subsoil anomalies may be due to the scattered limestone blocks that occur in the area. Moreover, the foundation walls have resistivity values that fall into the range of fractured limestone or limestone blocks. A step-wise or inclined foundation wall style has not been indicated through the parallel resistivity profiles. Copyright © 2005 John Wiley & Sons, Ltd. [source] | ||||||||||