Mechanisms of intrinsic stresses generation in sputtered amorphous Si: H films

1995 ◽  
Vol 10 (11) ◽  
pp. 2736-2741 ◽  
Author(s):  
Hiroki Takahashi ◽  
Hirotoshi Nagata ◽  
Haruki Kataoka ◽  
Hiroshi Takai

The relation between stresses of sputtered a-Si: H films and the film deposition conditions are investigated. The film stresses change from a large compressive stress of 1000 MPa to an almost stress-free one. They arise from distortions of the Si network via the following two mechanisms. The first results from the inclusion of the Ar-sputtering gas into the films, which provides volume expansion of the film network. The other is due to structural disorders, such as a deviation of the Si bond angle which is generated during the deposition processes. Moreover, it is found that Si–H terminations in the films contribute to reducing the film stresses because the Si–H termination breaks and relaxes the Si network. These effects can be realized as long as the Si–H terminations are homogeneously distributed in the films.

1976 ◽  
Vol 32 ◽  
pp. 577-588
Author(s):  
C. Mégessier ◽  
V. Khokhlova ◽  
T. Ryabchikova

My talk will be on the oblique rotator model which was first proposed by Stibbs (1950), and since received success and further developments. I shall present two different attempts at describing a star according to this model and the first results obtained in the framework of a Russian-French collaboration in order to test the precision of the two methods. The aim is to give the best possible representation of the element distributions on the Ap stellar surfaces. The first method is the mathematical formulation proposed by Deutsch (1958-1970) and applied by Deutsch (1958) to HD 125248, by Pyper (1969) to α2CVn and by Mégessier (1975) to 108 Aqr. The other one was proposed by Khokhlova (1974) and used by her group.


1899 ◽  
Vol 45 (191) ◽  
pp. 713-724
Author(s):  
F. Ashby Elkins ◽  
Jas. Middlemass

We think it will be generally acknowledged that the problem which the treatment of noisy, destructive, and dirty patients sets to their medical officers is greatest as regards their management at night. It is then undoubtedly that noise, destructiveness, and dirty habits have the greatest chance of getting free play, and it is then that the efforts for reformation have to be greatest. If these efforts are successful considerably more than half the problem will have been solved. It is to this part of the question, viz. the supervision of such patients during the night, that we desire in this paper to direct attention. At the outset it may be stated that our proposals are not theoretical. They are the result of practical experience gained during the past four years in the Sunderland Asylum. The special arrangements we propose to describe were instituted by one of us at the opening of the institution four years ago. At first a few cases were dealt with tentatively, but, as the first results were so encouraging, the number of cases was gradually increased, until all the patients who were restless, noisy, destructive, or of dirty habits came without exception to be dealt with. The asylum, situated at Ryhope, is a small one, containing only 350 beds, and on this account, as well as because it was new, it was conveniently suited for such an experiment. It may be well before going further to describe the arrangements now in existence there. There are 175 beds for each sex, made up as follows:—45 single rooms, one fully padded, and 2 half-padded; 2 small dormitories of 7 each, 2 of 13 each, 2 of 19 each, and 2 of 26 each. In the last two there is a night attendant, and one also in one of the dormitories for 19, which is the hospital ward. There is, in addition, a head night attendant who visits the patients in these dormitories and also all the remaining patients every hour, or oftener when necessary. There are thus 4 of a night staff for 175 patients. Though this is probably a large proportion compared to most public asylums, it is not claimed as a new departure in asylum management, as we are aware that in a number of asylums the advantage of having a large night staff is fully realised and acted on. The essential feature of the arrangements at Ryhope, to which we wish to direct attention, is the selection of cases placed in dormitories under constant supervision. Of course, all epileptics and suicidal patients are placed there. But, in addition, all recent cases of whatever kind, all dirty and destructive cases, and those who sleep badly and are in consequence inclined to chatter or be noisy, are also placed under constant supervision. Looked at from the other side, all single rooms and dormitories not under constant supervision are reserved for quiet and well-behaved patients who do not require any special attention during the night. This plan has been found to work exceedingly well, and since it was organised we have never had occasion to think of adopting any other. Another testimony to its effectiveness is that those of the staff who have the actual supervision of the patients and have had experience in other asylums are unanimous in their opinion that the arrangement is a very decided improvement. This opinion, let it be observed, is not based on the ground that now their duties are lighter than they were, because, as a matter of fact, they are more onerous.


1994 ◽  
Vol 336 ◽  
Author(s):  
G. De Cesare ◽  
F. Irrera ◽  
F. Lemmi ◽  
F. Palma ◽  
M. Tucci

ABSTRACTWe present a novel family of photodetectors based on hydrogenated amorphous Si/SiC p-i-n-i-p heterostructures. Front p-i-n and rear n-i-p diodes work one as a detector and the other as a load impedance, depending on the polarity of the applied voltage. Due to different absorption at different wavelengths, the devices operate as bias-controlled light detectors in either the blue or the red regions. The energy gap and the thickness of the two intrinsic layers have been optimized to obtain a sharp wavelength selection (centered at 430 and 630 nm) with high rejection-ratios and good quantum efficiencies. The I-V characteristics and the device time response are investigated and simulated by SPICE.


Diamond-like carbon refers to forms of amorphous carbon and hydrogenated amorphous carbon containing a sizeable fraction of sp 3 bonding, which makes them mechanically hard, infrared transparent and chemically inert. This paper discusses the various thin film deposition processes used to form diamond-like carbon and the deposition mechanisms responsible for promoting the metastable sp 3 bonding.


1995 ◽  
Vol 82 (1) ◽  
pp. 44-47 ◽  
Author(s):  
Eric R. Trumble ◽  
J. Paul Muizelaar ◽  
John S. Myseros ◽  
Sung C. Choi ◽  
Brian B. Warren

✓ The use of colloid agents to achieve hypervolemia in the prevention and treatment of postsubarachnoid hemorrhage (post-SAH) vasospasm is included in the standard of care at many institutions. Risk profiles are necessary to ensure appropriate use of these agents. In a series of 85 patients with recent aneurysmal SAH, 26 developed clinical symptoms of vasospasm. Fourteen of the 26 were treated with hetastarch for volume expansion while the other 12 received plasma protein fraction (PPF). Clinically significant bleeding pathologies were noted in six patients who received hetastarch as a continuous intravenous infusion. Hetastarch increased partial thromboplastin time from a mean of 23.9 seconds to a mean of 33.1 seconds (p < 0.001) in all patients who received infusions of this agent, while no effect was noted in the 12 patients who received PPF infusions. No other coagulation parameters were altered. This study shows an increase in coagulopathy with the use of hetastarch as compared with the use of PPF for the treatment of postaneurysmal vasospasm.


2018 ◽  
Vol 82 (2) ◽  
pp. 347-365 ◽  
Author(s):  
Serena C. Tarantino ◽  
Michele Zema ◽  
Athos M. Callegari ◽  
Massimo Boiocchi ◽  
Michael A. Carpenter

ABSTRACTA natural olivenite single crystal was submitted to in situ high-temperature single-crystal X-ray diffraction from room temperature (RT) to 500°C. Unit-cell parameters were measured at regular intervals of 25°C, and complete datasets collected at T = 25, 50, 100, 150, 200, 250, 300, 400 and 500°C. Evolution of unit-cell parameters and structure refinements indicates that olivenite undergoes a structural phase transition from P21/n to Pnnm at ~200°C, and eventually becomes isostructural with the other members of the olivenite-mineral group. Volume expansion with temperature is larger in the monoclinic phase – where it follows a non-linear trend – than in the orthorhombic one. Axial and volume expansion coefficients of the orthorhombic olivenite phase are positive and linear and similar to those of the other Cu-bearing member of the mineral family, namely libethenite, but rather different from those of the Zn-analogue arsenate adamite.Distortion of Cu polyhedra is quite high in the olivenite monoclinic phase at RT and goes towards a relative regularization with increasing T until the phase transition occurs. In the orthorhombic phase, no significant variation of the polyhedral distortion parameters is observed with increasing temperature, and maximum expansion is along the b direction and governed by corner-sharing. Landau potential provides a good representation of the macroscopic changes associated with the phase transition, coupling between the strains and the order parameter is responsible for the nearly tricritical character of the transition.


Author(s):  
Milanesi Milanesi

This article presents the first results of the studies on the geographical content of the heart-shaped map of the world signed Cagi Acmet (1559), which has been made possible by the complete transliteration and translation of the work. The considered area, i.e. Central Asia, is presented and compared with 16th-century cartography. The Author draws from an in-depth examination of this area, as well as from the study of all the other parts of the map, the conclusion that the heart-shaped map is the work of the cartographer Giacomo Gastaldi, active in Venice between 1545 and 1566.


2020 ◽  
Author(s):  
Susana Barbosa ◽  
Mauricio Camilo ◽  
Carlos Almeida ◽  
José Almeida ◽  
Guilherme Amaral ◽  
...  

&lt;p&gt;&lt;span&gt;The study of the electrical properties of the atmospheric marine boundary layer is important as the effect of natural radioactivity in driving near surface ionisation is significantly reduced over the ocean, and the concentration of aerosols is also typically lower than over continental areas, allowing a clearer examination of space-atmosphere interactions. Furthermore, cloud cover over the ocean is dominated by low-level clouds and most of the atmospheric charge lies near the earth surface, at low altitude cloud tops. &lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;The relevance of electric field observations in the marine boundary layer is enhanced by the the fact that the electrical conductivity of the ocean air is clearly linked to global atmospheric pollution and aerosol content. The increase in aerosol pollution since the original observations made in the early 20th century by the survey ship Carnegie is a pressing and timely motivation for modern measurements of the atmospheric electric field in the marine boundary layer. Project SAIL (Space-Atmosphere-Ocean Interactions in the marine boundary Layer) addresses this challenge by means of an unique monitoring campaign on board the ship-rigged sailing ship NRP Sagres during its 2020 circumnavigation expedition. &lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;The Portuguese Navy ship NRP Sagres departed from Lisbon on January 5th in a journey around the globe that will take 371 days. Two identical field mill sensors (CS110, Campbell Scientific) are installed &lt;/span&gt;&lt;span&gt;o&lt;/span&gt;&lt;span&gt;n the mizzen mast, one at a height of 22 m, and the other at a height of 5 meters. &lt;/span&gt;&lt;span&gt;A visibility sensor (SWS050, Biral) was also set-up on the same mast in order to have measurements of the extinction coefficient of the atmosphere and assess fair-weather conditions.&lt;/span&gt;&lt;span&gt; Further observations include gamma radiation measured with a NaI(Tl) scintillator from 475 keV to 3 MeV, cosmic radiation up to 17 MeV, and atmospheric ionisation from a cluster ion counter (Airel). The&lt;/span&gt;&lt;span&gt; 1 Hz measurements of the atmospheric electric field&lt;/span&gt;&lt;span&gt; and from all the other sensors&lt;/span&gt;&lt;span&gt; are &lt;/span&gt;&lt;span&gt;linked to the same rigorous temporal reference frame and precise positioning through kinematic GNSS observations. &lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;Here the first results of the SAIL project will be presented, focusing on fair-weather electric field over the Atlantic. The observations obtained in the first three sections of the circumnavigation journey, including Lisbon (Portugal) - Tenerife (Spain), from 5 to 10 January, Tenerife - Praia (Cape Verde) from 13 to 19 January, and across the Atlantic from Cape Verde to Rio de Janeiro (Brasil), from January 22nd to February 14th, will be presented and discussed.&lt;/span&gt;&lt;/p&gt;


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