Germanium-On-Insulator (GeOI) structure realized by the Smart Cut™ technology

2004 ◽  
Vol 809 ◽  
Author(s):  
F. Letertre ◽  
C. Deguet ◽  
C. Richtarch ◽  
B. Faure ◽  
JM Hartmann ◽  
...  
Keyword(s):  
Cross Sections ◽  
Large Diameter ◽  
Bonding Layer ◽  
Detailed Characterization ◽  
Si Substrates ◽  
First Results ◽  
Defect Densities ◽  
Technological Options ◽  
Roughness Measurements

ABSTRACTFirst results on formation of thin film GeOI structures by the Smart Cut™ technology are presented in this paper. Thin single crystal layers of Ge have been successfully transferred, via oxide bonding layer, onto standard Si substrates with diameters ranging from 100 to 200 mm. Compared to SOI manufacturing, the development of GeOI requires adaptation to the available germanium material, since the starting material can be either bulk Ge or an epitaxial layer. Some results will be presented for GeOI formation according to the different technological options. Germanium splitting kinetics will be discussed and compared to already published results. To show good quality of the GeOI structures, detailed characterization has been done by TEM cross sections for defect densities, interfaces abruptness and layers homogeneities evaluation. AFM was used for surface roughness measurements. These results help define procedures that are required to achieve large diameter high quality GeOI structures.

Status of Large Diameter SiC Single Crystals at II-VI

2008 ◽  
Vol 600-603 ◽  
pp. 35-38 ◽  
Author(s):  
Avinash K. Gupta ◽  
Ilya Zwieback ◽  
Andrew E. Souzis ◽  
Murugesu Yoganathan ◽  
Thomas Anderson
Keyword(s):  
Single Crystals ◽  
Large Diameter ◽  
Lattice Curvature ◽  
Rocking Curve ◽  
Si Substrates ◽  
Edge Defects ◽  
New Generation ◽  
Sublimation Growth ◽  
Lattice Matched

II-VI is developing large-diameter SiC crystals to be used as lattice-matched, high thermal conductivity substrates for new generation GaN-based and SiC-based semiconductor devices. Large-diameter 6H SiC single crystals are grown at II-VI using our Advanced PVT sublimation growth process. Stable SI properties are achieved by compensation with vanadium, which results in high and spatially uniform resistivity, on the order of 1011 Ohm-cm. The quality of the presently grown 100 mm 6H SI substrates has been dramatically improved [1], and they are free of edge defects. Micropipe density in the 100 mm 6H SI substrates ranges from 2 to 8 cm-2 and dislocation density from 3·104 to 6·104 cm-2. X-ray rocking curves measured on as-sawn 100 mm 6H wafers showed edge-to-edge lattice curvature () between 0.1° and 0.3° and FWHM of the rocking curve between 50 and 100 arc-seconds

Pendeo Epitaxy Of 3C-SiC on Si Substrates

2000 ◽  
Vol 622 ◽  
Author(s):  
G.E. Carter ◽  
T. Zheleva ◽  
G. Melnychuck ◽  
B. Geil ◽  
K. Jones ◽  
...  
Keyword(s):  
Low Cost ◽  
Large Diameter ◽  
Side Wall ◽  
Cost Effective ◽  
Interface Layer ◽  
Lateral Epitaxial Overgrowth ◽  
Si Substrates ◽  
Device Applications ◽  
Sic Film

ABSTRACTPendeo Epitaxy is a type of Lateral Epitaxial Overgrowth (LEO) that instead of using a dielectric buffer layer, uses an etched substrate to grow laterally without an interface layer. We report the first successful growth of 3C-SiC on Si using Pendeo epitaxy. Rectangular stripes of 3C-SiC on (100) Si substrates were fabricated, along both the [110] and [100] directions. Pendeo epi was only observed for columns parallel to [001], indicating a preferred growth facet for Pendeo epi of 3C-SiC on Si. SEM and TEM investigations were performed to assess the material quality of the Pendeo 3C-SiC material. Films were grown for 60 min at 1310°C and film coalescence was achieved without evidence of voids where the growth fronts joined. TEM data indicate not only the growth of vertical and lateral 3C-SiC on the 3C-SiC seed layer but direct nucleation of 3C-SiC on the exposed Si columns side wall and trench bottom, despite the lack of a carbonization procedure. The quality of the Pendeo 3C-SiC film appears to be of high quality indicating that Pendeo epi of 3C-SiC on low-cost, large-diameter Si substrates may prove to be a cost effective way to grow device-grade SiC layers on Si substrates for device applications.

’Propylene glycolate’ used as a top coat seal to protect thick juice from degradation in ellipsoidal storage tanks

2013 ◽  
pp. 215-218
Author(s):  
Robert O. Hatch ◽  
Craig M. Giles ◽  
Jay S. Creiglow ◽  
David R. Smith
Keyword(s):  
Propylene Glycol ◽  
Barrier Layer ◽  
Chemical Properties ◽  
Polypropylene Glycol ◽  
Storage Tanks ◽  
First Results ◽  
Thick Juice

The use of sodium propylene glycol for thick juice storage was investigated at Spreckels Sugar Company, in Brawley, California (USA). Sodium-polypropylene glycol has a density of 1.07 and does not mix with thick juice. Therefore it is suitable as a barrier layer. Chemical properties of propylene glycol, and the deposition on the top of thick juice are described. First results of the last campaign are compared with data from previous years. A significantly lower tendency in the reduction of the quality of the thick juice was found.

Effects and Risks of Distance Learning in Higher Education

2020 ◽  
pp. 61-73
Author(s):  
Yu. M. Tsygalov
Keyword(s):  
Higher Education ◽  
Distance Learning ◽  
Online Education ◽  
New Technology ◽  
Negative Consequences ◽  
Higher Education System ◽  
First Results ◽  
Spread Of Infection ◽  
The Cost

The forced work of Russian universities remotely in the context of the pandemic (COVID-19) has generated a lot of discussion about the benefits of the new form of education. The first results were summed up and reports were presented, the materials of which showed that the main goal of online education — the prevention of the spread of infection, - has been achieved. Against this background, proposals and publications have appeared substantiating the effectiveness of the massive introduction of distance learning in Russia, including in higher education. However, the assessment of such training by the population and students in publications and in social networks was predominantly negative and showed that the number of emerging problems exceeds the possible benefits of the new educational technology. Based on the analysis of the materials of publications and personal experience of teaching online, the potential benefits and problems of distance learning in higher education in Russia are considered. It is proposed to consider the effects separately for the suppliers of new technology (government, universities) and consumers (students, teachers, society). It is substantiated that the massive introduction of online education allows not only to reduce the negative consequences of epidemics, but also to reduce budgetary funding for universities, optimize the age composition of teachers, and reduce the cost of maintaining educational buildings. However, there will be a leveling / averaging of the quality of education, and responsibility for the quality of training will shift from the state/universities to students. The critical shortcomings of online education are the low degree of readiness of the digital infrastructure, the lack of a mechanism for identifying and monitoring the work of students, information security problems, and the lack of trust in such training of the population. The massive use of online education creates a number of risks for the country, the most critical of which is the destruction of the higher education system and a drop in the effectiveness of personnel training. The consequences of this risk realization are not compensated by any possible budget savings.

Creation of physiologic rhythm by closed loop stimulation in heart failure patients with severe chronotropic incompetence: worldwide first results of a pilot study

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
J Proff ◽  
B Merkely ◽  
R Papp ◽  
C Lenz ◽  
P.J Nordbeck ◽  
...  
Keyword(s):  
Heart Rate ◽  
Closed Loop ◽  
Funding Source ◽  
Chronotropic Incompetence ◽  
First Results ◽  
The Mean ◽  
Group 2 ◽  
Group 1

Abstract Background The prevalence of chronotropic incompetence (CI) in heart failure (HF) population is high and negatively impacts prognosis. In HF patients with an implanted cardiac resynchronisation therapy (CRT) device and severe CI, the effect of rate adaptive pacing on patient outcomes is unclear. Closed loop stimulation (CLS) based on cardiac impedance measurement may be an optimal method of heart rate adaptation according to metabolic need in HF patients with severe CI. Purpose This is the first study evaluating the effect of CLS on the established prognostic parameters assessed by the cardio-pulmonary exercise (CPX) testing and on quality of life (QoL) of the patients. Methods A randomised, controlled, double-blind and crossover pilot study has been performed in CRT patients with severe CI defined as the inability to achieve 70% of the age-predicted maximum heart rate (APMHR). After baseline assessment, patients were randomised to either DDD-CLS pacing (group 1) or DDD pacing at 40 bpm (group 2) for a 1-month period, followed by crossover for another month. At baseline and at 1- and 2-month follow-ups, a CPX was performed and QoL was assessed using the EQ-5D-5L questionnaire. The main endpoints were the effect of CLS on ventilatory efficiency (VE) slope (evaluated by an independent CPX expert), the responder rate defined as an improvement (decrease) of the VE slope by at least 5%, percentage of maximal predicted heart rate reserve (HRR) achieved, and QoL. Results Of the 36 patients enrolled in the study, 20 fulfilled the criterion for severe CI and entered the study follow-up (mean age 68.9±7.4 years, 70% men, LVEF=41.8±9.3%, 40%/60% NYHA class II/III). Full baseline and follow-up datasets were obtained in 17 patients. The mean VE slope and HRR at baseline were 34.4±4.4 and 49.6±23.8%, respectively, in group 1 (n=7) and 34.5±12.2 and 54.2±16.1% in group 2 (n=10). After completing the 2-month CPX, the mean difference between DDD-CLS and DDD-40 modes was −2.4±8.3 (group 1) and −1.2±3.5 (group 2) for VE slope, and 17.1±15.5% (group 1) and 8.7±18.8% (group 2) for HRR. Altogether, VE slope improved by −1.8±2.95 (p=0.31) in DDD-CLS versus DDD-40, and HRR improved by 12.9±8.8% (p=0.01). The VE slope decreased by ≥5% in 47% of patients (“responders to CLS”). The mean difference in the QoL between DDD-CLS and DDD-40 was 0.16±0.25 in group 1 and −0.01±0.05 in group 2, resulting in an overall increase by 0.08±0.08 in the DDD-CLS mode (p=0.13). Conclusion First results of the evaluation of the effectiveness of CLS in CRT patients with severe CI revealed that CLS generated an overall positive effect on well-established surrogate parameters for prognosis. About one half of the patients showed CLS response in terms of improved VE slope. In addition, CLS improved quality of life. Further clinical research is needed to identify predictors that can increase the responder rate and to confirm improvement in clinical outcomes. Funding Acknowledgement Type of funding source: Private company. Main funding source(s): Biotronik SE & Co. KG

Testing the Accuracy of Surface Roughness Measurements Carried out with a Portable Profilometer

2015 ◽  
Vol 637 ◽  
pp. 69-73 ◽  
Author(s):  
Krzysztof Stępień
Keyword(s):  
Surface Roughness ◽  
Measurement Accuracy ◽  
Environmental Changes ◽  
Experimental Tests ◽  
Evaluation Procedure ◽  
Human Errors ◽  
Modern Manufacturing ◽  
Machine Parts ◽  
Roughness Measurements

Surface roughness is a factor that has a vital influence on overall quality of machine parts. This is the reason why proper measurements of surface roughness are a matter of great importance in modern manufacturing technology. Nowadays portable profilometers are common instruments to be used under industrial conditions. Measurements with such instruments can be affected by numerous factors, for example environmental changes, human errors of an operator, etc. This paper discusses problem of an evaluation of measurement accuracy of portable profilometers. It also describes the evaluation procedure and presents results experimental tests.

Do changes in light direction affect absorption profiles in leaves?

2010 ◽  
Vol 37 (5) ◽  
pp. 403 ◽  
Author(s):  
Craig R. Brodersen ◽  
Thomas C. Vogelmann
Keyword(s):  
Cross Sections ◽  
Incident Light ◽  
Monochromatic Light ◽  
Diffuse Light ◽  
Spongy Mesophyll ◽  
Light Regimes ◽  
Direct Light ◽  
Direct Measurements ◽  
Leaf Level

Leaf anatomy plays a functional role in propagating light through the leaf; palisade mesophyll has been shown to facilitate the channelling of collimated light deeper into the spongy mesophyll. Direct measurements of the propagation of diffuse light into the leaf, however, are absent. Using chlorophyll fluorescence imaging of leaf cross-sections, we measured light absorption profiles in leaves under direct (collimated), diffuse and low-angle monochromatic light. Low-angle and diffuse light was absorbed closer to the irradiated surface than direct light perpendicular to the surface. The shapes of internal absorption profiles indicated that leaves were influenced by the directional quality of the incident light. In addition, absorption profiles revealed that leaves were not simple light absorbing objects and that cellular anatomy influences the direction of light travelling into the mesophyll. These findings also suggest a mechanism for previously measured differences in leaf level photosynthesis under opposing light regimes.

Constraint-Based Reverse Engineering From Ultrasound Cross-Sections

1997 ◽  
Author(s):  
Jai Menon ◽  
Ranjit Desai ◽  
Jay Buckey
Keyword(s):  
Reverse Engineering ◽  
Cross Sections ◽  
Biomedical Applications ◽  
Engineering Application ◽  
Volume Data ◽  
Cross Sectional ◽  
Reverse Engineer ◽  
Network Bandwidth ◽  
Complex Topology

Abstract This paper extends the “cross-sectional” approach for reverse engineering, used abundantly in biomedical applications, to the mechanical domain. We propose a combination of “projective” and cross-sectional algorithms for handling physical artifacts with complex topology and geometry. In addition, the paper introduces the concept of constraint-based reverse engineering, where the constraint parameters could include one or more of the following: time, storage (memory, disk-space), network bandwidth, Quality of Service (output-resolution), and so forth. We describe a specific reverse-engineering application which uses ultrasound (tilt-echo) imaging to reverse engineer spatial enumeration (volume) representations from cross-sectional data. The constraint here is time, and we summarize how our implementation can satisfy real-time reconstruction for distribution of the volume data on the internet. We present results that show volume representations computed from static objects. Since the algorithms are tuned to satisfy time constraints, this method is extendable to reverse engineer temporally-varying (elastic) objects. The current reverse engineering processing time is constrained by the data-acquisition (tilt-echo imaging) process, and the entire reverse engineering pipeline has been optimized to compute incremental volume representations in the order of 3 seconds on a network of four processors.

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