Properties of SiO2 Films Fabricated by Microwave Ecr Plasma Processing with and Without Energetic Particle Bombardment During Film Deposition Part I. Fabrication Processes and Physical Properties

1991 ◽  
Vol 223 ◽  
Author(s):  
T. T. Chau ◽  
S. R. Mejia ◽  
K. C. Kao
Keyword(s):  
Silicon Dioxide ◽  
Particle Bombardment ◽  
Energetic Particle ◽  
Deposition Temperature ◽  
Film Growth ◽  
Plasma Processing ◽  
Film Deposition ◽  
Ecr Plasma ◽  
Group A ◽  
Group B

ABSTRACTSilicon dioxide (SiO2) films were fabricated by microwave ECR plasma processing. Two groups of films were fabricated; group A with the substrates placed in a position directly facing the plasma so that the substrates as well as the on-growing films were subjected to bombardment of energetic particles produced in the plasma, and group B with the substrates placed in a processing chamber physically separated from the plasma chamber in order to prevent or suppress the damaging effects resulting from these energetic particle bombardment. The systems used for fabricating these two different groups of samples are described. The films were deposited at various deposition temperatures. On the basis of the deposition rate as a function of deposition temperature the film growth for group A samples is due mainly to mass-limited reaction, and that for group B samples is due to surface rate limited reaction. The stoichiometric level for group A does not change with deposition temperature though the films density increases with increasing deposition temperature. However, group B samples exhibit an off-stoichiometric property but they become highly stoichiometric as the deposition temperature is increased beyond 200 °C

Properties of SiO2 Films Fabricated by Microwave ECR Plasma Processing with and without Energetic Particle Bombardment During Film Deposition. Part II: Electronic Properties

1991 ◽  
Vol 225 ◽  
Author(s):  
T. T Chau ◽  
S. R. Mejia ◽  
K. C. Kao
Keyword(s):  
Electronic Properties ◽  
Particle Bombardment ◽  
Energetic Particle ◽  
Plasma Processing ◽  
Film Deposition ◽  
Dust Particles ◽  
Phase Reaction ◽  
Ecr Plasma ◽  
Group A ◽  
Group B

ABSTRACTSilicon dioxide (SiO2) films were fabricated by microwave ECR plasma processing at 300°C, the range of the film thicknesses being 200 - 300 Å. Two groups of films were fabricated; group A with the substrates placed in a position directly facing the plasma so that the substrates as well as the on-growing films were subjected to bombardment of energetic particles produced in the plasma, and group B with the substrates placed in a processing chamber physically separated from the plasma chamber in order to prevent or suppress the damaging effects resulting from these energetic particle bombardment. It has been found that group A films are poor in both the capacitance-voltage (C-V) and the current-voltage (I-V) characteristics, possibly due to dust particles created by the gas phase reaction of SiH4 and ionic bombardment and radiation damage during film deposition. Group B films, on the other hands, exhibit good electronic properties. On the basis of their I-V and C-V characteristics, group B films yield an average breakdown strength of about 10 MV/cm, an oxide bulk charge density on the order of 1014 q/cm3 and an interface trap density on the order of 1011 cm−2 eV−1 which are approaching those of high quality thermally grown oxides and they are suitable for use as gate insulator for MOS devices.

Ion-Beam-Assisted Deposition and Synthesis

MRS Bulletin ◽  
1987 ◽  
Vol 12 (2) ◽  
pp. 40-51 ◽  
Author(s):  
S.M. Rossnagel ◽  
J.J. Cuomo
Keyword(s):  
Thin Film ◽  
Particle Bombardment ◽  
Energetic Particle ◽  
Ion Beam ◽  
Chemical Properties ◽  
Film Surface ◽  
Arrival Rate ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Deposition Techniques

Concurrent energetic particle bombardment during film deposition can strongly modify the structural and chemical properties of the resulting thin film. The interest in this technique, ion-assisted deposition, comes about because it can be used to produce thin films with properties not achievable by conventional deposition. Bombardment by low energy ions occurs during almost all plasma-based thin film deposition techniques. Bombardment of a growing film, particularly by accelerated ions, can also be combined with non-plasma-based deposition techniques, such as evaporation, to simulate some of the effects observed with sputtering. The bombarding particle flux is usually controllable so that the arrival rate, energy, and species can be independently varied from the depositing flux. Thus, a basic aspect of ion-beam-based deposition techniques is the “control” often absent in plasma-based techniques. In plasmas, the voltage, current, and pressure are all interdependent. The energetic bombardment at the substrate-film interface depends on the various properties of the plasma, as does the deposition rate. It is often difficult, or even impossible, to decouple these processes. With ion-beam-based deposition techniques, the ion bombardment is essentially independent of the deposition process, and both can be more easily controlled.The incident energetic particle contributes some of its energy or momentum to irreversibly change the dynamics of the film surface. The incident particle may also be incorporated into the growing film, changing the film's chemical nature. The changes induced by particle bombardment during deposition are often not characteristic of equilibrium thermodynamics because the incident particle's energy is often many times the local adsorption or binding energy.

scholarly journals Evaluation of Surface Conditioning of Zirconia and Its Effect on Bonding to Resin-Luting Agent

2013 ◽  
Vol 3 (1) ◽  
pp. 7-10
Author(s):  
Sonu Gargava ◽  
Sabita M Ram
Keyword(s):  
Bond Strength ◽  
Silicon Dioxide ◽  
Shear Bond Strength ◽  
Composite Resin ◽  
Testing Machine ◽  
Acrylic Resin ◽  
Surface Conditioning ◽  
Luting Agent ◽  
Group A ◽  
Group B

ABSTRACT Zirconia, a recently introduced ceramic exhibits excellent esthetic qualities and demonstrates outstanding flexural strength but its extensive use, requires a reliable bond of Zirconia with resinluting agent. Resin Zirconia bonding cannot be achieved as the material is resistant to common etching procedures used for other glass containing ceramics. With surface conditioning increased adhesion between Zirconia and resin-luting agent can be successfully achieved. Aim Aim of this study was to evaluate surface conditioning of Zirconia and its effect on bonding to resin-luting agent. Materials and Methods Fifteen blocks of Zirconia (VITA Zirconia) were fabricated in the laboratory according to manufacturer's instructions and embedded in acrylic resin to get 15 Zirconia samples. Fifteen composite resin cylinders were prepared one for each Zirconia sample. All the 15 Zirconia samples were divided into three groups of five samples each. Group A: Was kept as control with no surface conditioning done. Group B: Surface conditioning was done with 30 µ silicon dioxide. Group C: Surface conditioning was done with 110 µ aluminum oxide. Composite resin cylinders were cemented on the Zirconia samples using a resin-luting agent (Panavia F). The samples were subjected to universal testing machine to evaluate shear bond strength and the data was statistically analyzed by oneway ANOVA. Results Group A showed least shear bond strength. Shear bond strength of group C was greater than group A while group B showed highest shear bond strength. Conclusion Surface conditioning results in significant increase bond strength between Zirconia and resin-luting agent. Among the two methods surface conditioning with 30 µ silicon dioxide is much better and efficient method. How to cite this article Gargava S, Ram SM. Evaluation of Surface Conditioning of Zirconia and Its Effect on Bonding to Resin-Luting Agent. J Contemp Dent 2013;3(1):7-10.

DLC thin film growth under energetic particle bombardment: a comparison between PLD and rf-bias enhanced PLD

1998 ◽  
Author(s):  
Thomas Klotzbuecher ◽  
Jens Gottmann ◽  
M. Meyer ◽  
David A. Wesner ◽  
Ernst-Wolfgang Kreutz
Keyword(s):  
Thin Film ◽  
Particle Bombardment ◽  
Energetic Particle ◽  
Film Growth ◽  
Thin Film Growth

An ultrastructural study of sertoli cells in two geographically isolated populations of Aphanius dispar

1992 ◽  
Vol 50 (1) ◽  
pp. 548-549
Author(s):  
Taber A. Ba-Omar ◽  
Philip F. Prentis
Keyword(s):  
Ultrastructural Level ◽  
Uranyl Acetate ◽  
Freshwater Teleost ◽  
Isolated Populations ◽  
En Bloc ◽  
The North ◽  
Group A ◽  
Ultrathin Sections ◽  
Group B ◽  
Geographically Isolated

We have recently carried out a study of spermiogenic differentiation in two geographically isolated populations of Aphanius dispar (freshwater teleost), with a view to ascertaining variation at the ultrastructural level. The sampling areas were the Jebel Al Akhdar in the north (Group A) and the Dhofar region (Group B) in the south. Specimens from each group were collected, the testes removed, fixed in Karnovsky solution, post fixed in OsO, en bloc stained with uranyl acetate and then routinely processed to Agar 100 resin, semi and ultrathin sections were prepared for study.

Comparison of one-year prognosis of patients classified as chronic critical lower limb ischaemia according to TASC II or European consensus definition in the COPART cohort

VASA ◽  
2015 ◽  
Vol 44 (3) ◽  
pp. 0220-0228 ◽  
Author(s):  
Marion Vircoulon ◽  
Carine Boulon ◽  
Ileana Desormais ◽  
Philippe Lacroix ◽  
Victor Aboyans ◽  
...  
Keyword(s):  
Medical Treatment ◽  
Critical Limb Ischaemia ◽  
Limb Ischaemia ◽  
Medical Group ◽  
Consensus Definition ◽  
Transcutaneous Oxygen ◽  
European Consensus ◽  
Group A ◽  
One Year ◽  
Group B

Background: We compared one-year amputation and survival rates in patients fulfilling 1991 European consensus critical limb ischaemia (CLI) definition to those clas, sified as CLI by TASC II but not European consensus (EC) definition. Patients and methods: Patients were selected from the COPART cohort of hospitalized patients with peripheral occlusive arterial disease suffering from lower extremity rest pain or ulcer and who completed one-year follow-up. Ankle and toe systolic pressures and transcutaneous oxygen pressure were measured. The patients were classified into two groups: those who could benefit from revascularization and those who could not (medical group). Within these groups, patients were separated into those who had CLI according to the European consensus definition (EC + TASC II: group A if revascularization, group C if medical treatment) and those who had no CLI by the European definition but who had CLI according to the TASC II definition (TASC: group B if revascularization and D if medical treatment). Results: 471 patients were included in the study (236 in the surgical group, 235 in the medical group). There was no difference according to the CLI definition for survival or cardiovascular event-free survival. However, major amputations were more frequent in group A than in group B (25 vs 12 %, p = 0.046) and in group C than in group D (38 vs 20 %, p = 0.004). Conclusions: Major amputation is twice as frequent in patients with CLI according to the historical European consensus definition than in those classified to the TASC II definition but not the EC. Caution is required when comparing results of recent series to historical controls. The TASC II definition of CLI is too wide to compare patients from clinical trials so we suggest separating these patients into two different stages: permanent (TASC II but not EC definition) and critical ischaemia (TASC II and EC definition).

Absorbable suture material in carotid surgery

VASA ◽  
2015 ◽  
Vol 44 (6) ◽  
pp. 451-457 ◽  
Author(s):  
Vincenzo Gasbarro ◽  
Luca Traina ◽  
Francesco Mascoli ◽  
Vincenzo Coscia ◽  
Gianluca Buffone ◽  
...  
Keyword(s):  
Suture Material ◽  
Absorbable Suture ◽  
Paediatric Surgery ◽  
Carotid Surgery ◽  
Suture Materials ◽  
Absorbable Suture Material ◽  
Absorbable Sutures ◽  
Group A ◽  
Group B

Abstract. Background: Absorbable sutures are not generally accepted by most vascular surgeons for the fear of breakage of the suture line and the risk of aneurysmal formation, except in cases of paediatric surgery or in case of infections. Aim of this study is to provide evidence of safety and efficacy of the use of absorbable suture materials in carotid surgery. Patients and methods: In an 11 year period, 1126 patients (659 male [58.5 %], 467 female [41.5 %], median age 72) underwent carotid endarterectomy for carotid stenosis by either conventional with primary closure (cCEA) or eversion (eCEA) techniques. Patients were randomised into two groups according to the type of suture material used. In Group A, absorbable suture material (polyglycolic acid) was used and in Group B non-absorbable suture material (polypropylene) was used. Primary end-point was to compare severe restenosis and aneurysmal formation rates between the two groups of patients. For statistical analysis only cases with a minimum period of follow-up of 12 months were considered. Results: A total of 868 surgical procedures were considered for data analysis. Median follow-up was 6 years (range 1-10 years). The rate of postoperative complications was better for group A for both cCEA and eCEA procedures: 3.5 % and 2.0 % for group A, respectively, and 11.8 % and 12.9 % for group B, respectively. Conclusions: In carotid surgery, the use of absorbable suture material seems to be safe and effective and with a general lower complications rate compared to the use of non-absorbable materials.

Randomized trial of medical compression stockings versus two-layer short-stretch bandaging in the management of venous leg ulcers

Phlebologie ◽  
2009 ◽  
Vol 38 (04) ◽  
pp. 157-163 ◽  
Author(s):  
A. Franek ◽  
L. Brzezinska-Wcislo ◽  
E. Blaszczak ◽  
A. Polak ◽  
J. Taradaj
Keyword(s):  
Drug Therapy ◽  
Randomized Clinical Trials ◽  
Therapy Group ◽  
Long Term Results ◽  
Leg Ulcers ◽  
Compression Stockings ◽  
Venous Leg Ulcers ◽  
Group A ◽  
Group B ◽  
Medical Compression Stockings

SummaryA prospective randomized clinical trial was undertaken to compare a medical compression stockings with two-layer short-stretch bandaging in the management of venous leg ulcers. Study endpoints were number of completely healed wounds and the clinical parameters predicting the outcome. Patients, methods: Eighty patients with venous leg ulcers were included in this study, and ultimately allocated into two comparative groups. Group A consisted of 40 patients (25 women, 15 men). They were treated with the compression stockings (25–32 mmHg) and drug therapy. Group B consisted of 40 patients (22 women, 18 men). They were treated with the short-stretch bandages (30–40 mmHg) and drug therapy, administered identically as in group A. Results: Within two months the 15/40 (37.50%) patients in group A and 5/40 (12.50%) in group B were healed completely (p = 0.01). For patients with isolated superficial reflux, the healing rates at two months were 45.45% (10/22 healed) in group A and 18.18% (4/22 healed) in group B (p = 0.01). For patients with superficial plus deep reflux, the healing rates were 27.77% (5/18 healed) in group A and 5.55% (1/18 healed) in group B (p = 0.002). Comparison of relative change of the total surface area (61.55% in group A vs. 23.66% in group B), length (41.67% in group A vs. 27.99% in group B), width (46.16% in group A vs. 29.33% in group B), and volume (82.03% in group A vs. 40.01% in group B) demonstrated difference (p = 0.002 in all comparisons) in favour of group A. Conclusion: The medical compression stockings are extremely useful therapy in enhancement of venous leg ulcer healing (both for patients with superficial and for patients who had superficial plus deep reflux). Bandages are less effective (especially for patients with superficial plus deep reflux, where the efficiency compared to the stockings of applied compression appeared dramatically low). These findings require confirmation in other randomized clinical trials with long term results.

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