scholarly journals Plasma processing and chemistry

2002 ◽  
Vol 74 (3) ◽  
pp. 369-380 ◽  
Author(s):  
Daniel C. Schram
Keyword(s):  
Surface Science ◽  
Materials Science ◽  
Plasma Deposition ◽  
High Growth ◽  
Radical Mechanism ◽  
Short Time ◽  
Further Development ◽  
C2h Radical ◽  
Very High ◽  
Monolayer Coverage

Plasma deposition and plasma conversion can be characterized by five steps: production by ionization, transfer of chemistry to precursors, transport of radicals to the surface, surface interactions with deposition, recirculation and generation of new monomers. For very fast deposition, large flows of radicals are needed and a regime is reached, in which monolayer coverage is reached in a very short time. Such large flows of radicals can be obtained by ion-induced interactions, as the C2H radical from acetylene for a-C:H deposition, or by H atom abstraction as the SiH3 radical from SiH4 for a-Si:H deposition. These radicals with intermediate sticking coefficient are advantageous as they are mobile and have a finite dwelling time at the surface. By such a pure radical mechanism, good layers can be formed with very high growth rates, if large radical fluxes can be reached. This regime of high fluence is also interesting for conversion, of which ammonia formation from hydrogen and nitrogen atoms is given as an example. These new approaches offer new possibilities for further development of the field in close connection with surface science, catalysis, and materials science.

Versatile High Rate Plasma Deposition and Processing with very high Frequency Excitation

1997 ◽  
Vol 467 ◽  
Author(s):  
M. Heintze
Keyword(s):  
Growth Rates ◽  
High Frequency ◽  
Plasma Deposition ◽  
Excitation Frequency ◽  
High Growth ◽  
Surface Reactivity ◽  
High Rate ◽  
Plasma Diagnostic ◽  
Very High Frequency ◽  
Very High

ABSTRACTThe interest in plasma deposition using very high frequency (VHF) excitation arose after the preparation of a-Si:H at high growth rates was demonstrated. Subsequently the improved process flexibility and the control of material properties offered by the variation of the plasma excitation frequency was recognized. The preparation of amorphous and microcrystalline thin films in a VHF-plasma is described. The increased growth rates have been attributed to an enhancement of film precursor formation at VHF, to the decreased sheath thickness as well as to an enhancement of the surface reactivity by positive ions. Plasma diagnostic investigations show that the parameters mainly affected by the excitation frequency are the ion flux to the electrodes as well as the sheaths potentials and widths, rather than the plasma density.

Development of the UHV-STM

1990 ◽  
Vol 48 (1) ◽  
pp. 322-323
Author(s):  
M. Iwatsuki ◽  
S. Kitamura ◽  
A. Mogami
Keyword(s):  
Surface Science ◽  
Real Space ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Great Promise ◽  
Force Microscopy ◽  
Atomic Force ◽  
Stm Image ◽  
Surface Construction ◽  
Very High

Since Binnig, Rohrer and associates observed real-space topographic images of Si(111)-7×7 and invented the scanning tunneling microscope (STM),1) the STM has been accepted as a powerful surface science instrument.Recently, many application areas for the STM have been opened up, such as atomic force microscopy (AFM), magnetic force microscopy (MFM) and others. So, the STM technology holds a great promise for the future.The great advantages of the STM are its high spatial resolution in the lateral and vertical directions on the atomic scale. However, the STM has difficulty in identifying atomic images in a desired area because it uses piezoelectric (PZT) elements as a scanner.On the other hand, the demand to observe specimens under UHV condition has grown, along with the advent of the STM technology. The requirment of UHV-STM is especially very high in to study of surface construction of semiconductors and superconducting materials on the atomic scale. In order to improve the STM image quality by keeping the specimen and tip surfaces clean, we have built a new UHV-STM (JSTM-4000XV) system which is provided with other surface analysis capability.

Very High Growth Rate of 4H-SiC Using MTS as Chloride-Based Precursor

2008 ◽  
Vol 600-603 ◽  
pp. 115-118 ◽  
Author(s):  
Henrik Pedersen ◽  
Stefano Leone ◽  
Anne Henry ◽  
Franziska Christine Beyer ◽  
Vanya Darakchieva ◽  
...  
Keyword(s):  
Growth Rate ◽  
Linear Dependence ◽  
Growth Rates ◽  
Molar Fraction ◽  
High Growth ◽  
High Growth Rate ◽  
Epitaxial Layers ◽  
Single Precursor ◽  
Very High

The chlorinated precursor methyltrichlorosilane (MTS), CH3SiCl3, has been used to grow epitaxial layers of 4H-SiC in a hot wall CVD reactor, with growth rates as high as 170 µm/h at 1600°C. Since MTS contains both silicon and carbon, with the C/Si ratio 1, MTS was used both as single precursor and mixed with silane or ethylene to study the effect of the C/Si and Cl/Si ratios on growth rate and doping of the epitaxial layers. When using only MTS as precursor, the growth rate showed a linear dependence on the MTS molar fraction in the reactor up to about 100 µm/h. The growth rate dropped for C/Si < 1 but was constant for C/Si > 1. Further, the growth rate decreased with lower Cl/Si ratio.

scholarly journals Vegetative growth of grasslands based on hyper-temporal NDVI data from the Modis sensor

2016 ◽  
Vol 51 (7) ◽  
pp. 858-868
Author(s):  
Marcos Cicarini Hott ◽  
Luis Marcelo Tavares de Carvalho ◽  
Mauro Antonio Homem Antunes ◽  
Polyanne Aguiar dos Santos ◽  
Tássia Borges Arantes ◽  
...  
Keyword(s):  
Vegetative Growth ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
High Growth ◽  
Growth Index ◽  
Data Series ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Very High

Abstract: The objective of this work was to analyze the development of grasslands in Zona da Mata, in the state of Minas Gerais, Brazil, between 2000 and 2013, using a parameter based on the growth index of the normalized difference vegetation index (NDVI) from the moderate resolution imaging spectroradiometer (Modis) data series. Based on temporal NDVI profiles, which were used as indicators of edaphoclimatic conditions, the growth index (GI) was estimated for 16-day periods throughout the spring season of 2012 to early 2013, being compared with the average GI from 2000 to 2011, used as the reference period. Currently, the grassland areas in Zona da Mata occupy approximately 1.2 million hectares. According to the used methods, 177,322 ha (14.61%) of these grassland areas have very low vegetative growth; 577,698 ha (45.96%) have low growth; 433,475 ha (35.72%) have balanced growth; 39,980 ha (3.29%) have high growth; and 5,032 ha (0.41%) have very high vegetative growth. The grasslands had predominantly low vegetative growth during the studied period, and the NDVI/Modis series is a useful source of data for regional assessments.

Etching and Surface Smoothing with Gas-Cluster Ion Beams

1999 ◽  
Vol 585 ◽  
Author(s):  
D. B. Fenner ◽  
R. P. Torti ◽  
L. P. Allen ◽  
N. Toyoda ◽  
A. R. Kirkpatrick ◽  
...  
Keyword(s):  
Surface Science ◽  
Ion Beam ◽  
Surface Processing ◽  
Figures Of Merit ◽  
Cluster Ion Beams ◽  
Cluster Ion ◽  
Gas Clusters ◽  
Gas Cluster Ion Beam ◽  
Microelectronic Materials ◽  
Very High

AbstractSurface processing of microelectronic materials by bombardment with nanoparticles of condensed gases (i.e., clusters) in the form of an ion beam, makes possible etching and smoothing of those surfaces to very high figures of merit. As this is not possible with any conventional ion method, gas-cluster ion-beam systems have great potential in manufacturing. The formation of gas clusters and their collision with surfaces provides an interesting arena for novel physics and surface science. This paper outlines a physical model for the clusters and surface interactions, and provides examples of surface processing. In particular, the reduction of surface roughness while etching by cluster-ion bombardment is illustrated for various materials utilized in microelectronics.

scholarly journals Production of radioisotopes within a plasma focus device

2005 ◽  
Vol 20 (1) ◽  
pp. 33-37 ◽  
Author(s):  
Ergisto Angeli ◽  
Agostino Tartari ◽  
Michele Frignani ◽  
Vincenzo Molinari ◽  
Domiziano Mostacci ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Plasma Focus ◽  
Reaction Rates ◽  
Experimental Production ◽  
Endogenous Production ◽  
The Us ◽  
Further Development ◽  
Radio Isotopes ◽  
Very High

In recent years, research conducted in the US and in Italy has demonstrated production of radioisotopes in plasma focus devices, and particularly, on what could be termed "endogenous" production, to wit, production within the plasma it self, as opposed to irradiation of tar gets. This technique relies on the formation of localized small plasma zones characterized by very high densities and fairly high temperatures. The conditions prevailing in these zones lead to high nuclear reaction rates, as pointed out in previous work by several authors. Further investigation of the cross sections involved has proven necessary to model the phenomena involved. In this paper, the present status of research in this field is re viewed, both with regards to cross section models and to experimental production of radio isotopes. Possible out comes and further development are discussed.

scholarly journals E-Service Quality dan E-Promotion Terhadap Keputusan Pembelian Konsumen pada Website Traveloka.com

Competitive ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 106-114
Author(s):  
Aditia Sovia Pramudita ◽  
Rahayu Eka Agustia
Keyword(s):  
Service Quality ◽  
Descriptive Analysis ◽  
Linear Regression Analysis ◽  
High Growth ◽  
Multiple Linear Regression Analysis ◽  
High Growth Rate ◽  
Purchasing Decisions ◽  
Quantitative Design ◽  
Service Purchasing ◽  
Very High

E-Commerce has a very high growth rate which the needs of quickly and precisely are the main target in the e-commerce business. This study aims to determine how consumers respond to the implementation of e-service quality website, e-promotion website which leads into consumer purchasing decisions at Traveloka using a descriptive quantitative design with data collection techniques through a questionnaire. The method used in this research is descriptive analysis and multiple linear regression analysis. The results show that the effect of website e-service quality and website e-promotion on service purchasing decisions at Traveloka is positive and significant. The influence of e-service quality website and e-promotion website on purchasing decisions at Traveloka is 23%. While the rest is influenced by variables not included in this study.

Symposium

PEDIATRICS ◽  
1953 ◽  
Vol 11 (1) ◽  
pp. 82-84
Author(s):  
BRET RATNER ◽  
EMANUEL GRUNBERG ◽  
J. C. BURKE
Keyword(s):  
Pathogenic Bacteria ◽  
Isonicotinic Acid ◽  
Acid Hydrazide ◽  
High Growth ◽  
Test Tube ◽  
Strict Sense ◽  
Tubercle Bacillus ◽  
Synthetic Compound ◽  
Small Doses ◽  
Further Development

The discovery of streptomycin has shown the way by which therapeutic activity against the causative agent of tuberculosis can be found and evaluated in the laboratory prior to its administration in patients. A great number of substances synthesized by the chemist in his laboratory or isolated from natural sources have been found to exert activity against the bacillus of tuberculosis. Many of these show this effect only in the test tube and prove without effectiveness if studied in experimental animals infected with tuberculosis. The new antituberculous agent, isonicotinic acid hydrazide (rimifon®), is a rather simple synthetic compound which was found to be superior to known antituberculous drugs during early stages of the laboratory investigation. Rimifon® possesses not only a remarkably high growth inhibiting effect against the tubercle bacillus in the test tube but also unusual features if studied in infected animals. Most of the fundamental work which has been confirmed in laboratories all over the world was done in mice which were infected with high and fatal doses of human tubercle bacilli. In this infection rimifon® showed 4 characteristic properties which had not been observed with any of the known drugs: (1) the drug protected heavily infected mice after administration of very small doses, (2) the drug successfully prevented the multiplication of the tubercle bacilli in the infected tissues of the animal and therefore (3) produced a lasting protection after discontinuance of therapy, and (4) if given therapeutically in animals in which the disease had already produced its characteristic lesions the drug tended to stop further development of the disease and to prepare the ground for the final cure. In sharp contrast to the broad spectrum antibiotics acting on a multitude of pathogenic bacteria and even viruses, rimifon® is a specific drug in the strict sense of Ehrlich's concept of chemotherapy in that it exerts its activity only against the group of mycobacteria of which the most important representatives are the tubercle bacillus and bacillus of Hansen's disease (bacillus leprae).

Gram Scale and Room Temperature Functionalization of Boron Nitride Nanosheets for Water Treatment

NANO ◽  
2019 ◽  
Vol 14 (08) ◽  
pp. 1950107
Author(s):  
Shirin Daneshnia ◽  
Mohsen Adeli ◽  
Yaghoub Mansourpanah
Keyword(s):  
Water Treatment ◽  
Boron Nitride ◽  
Hexagonal Boron Nitride ◽  
Two Dimensional ◽  
Covalent Functionalization ◽  
Bet Analysis ◽  
Potential Applications ◽  
Short Time ◽  
Further Development ◽  
Straightforward Approach

Two-dimensional hexagonal boron nitride is a fascinating nanomaterial with a broad range of potential applications. However, further development of this nanomaterial is hampered because of its poor functionality and low processability. One of the efficient strategies for improving the processability of two-dimensional hexagonal boron nitride is the covalent functionalization of this nanomaterial. In this study, we report on a straightforward approach for functionalization of two-dimensional hexagonal boron nitride by lithium cyclopentadienyl and its application for water treatment. Cyclopentadienyl-functionalized boron nitride was characterized by different spectroscopy and microscopy methods as well as thermal and BET analysis. The synthesized nanomaterial was able to efficiently remove methylene blue from water in a short time. Adsorption capacity of this nanomaterial was as high as 476.3[Formula: see text]mg/g, which was superior to the nonfunctionalized boron nitride. Our results showed that cyclopentadienyl-functionalized boron nitride is a promising candidate for the removal of cationic pollutants from water.

scholarly journals Intravaginal Devices and GNSS Collars with Satellite Communication to Detect Calving Events in Extensive Beef Production in Northern Australia

2020 ◽  
Vol 12 (23) ◽  
pp. 3963
Author(s):  
Christie Pearson ◽  
Lucy Lush ◽  
Luciano A. González
Keyword(s):  
High Frequency ◽  
Satellite Communication ◽  
Satellite System ◽  
Behavioral Changes ◽  
Very High Frequency ◽  
Average Activity ◽  
Newborn Calves ◽  
Global Navigation Satellite ◽  
Further Development ◽  
Very High

Observing calves at birth may help to identify risk factors for, and reduce, calf loss in extensive beef systems. The objectives of this study were to: (1) evaluate two commercial satellite birth alert systems to enable the observation of newborn calves and (2) assess behavioral changes of cows around calving. Vaginal Implant Transmitters (VIT) paired with Global Navigation Satellite System (GNSS) collars were worn by 20 cows in Trial 1 and 10 cows in Trial 2 to identify birthing events. The VIT and GNSS collars contained a temperature sensor, accelerometer, and very high frequency (VHF) to communicate with a handheld tracker, and ultra-high frequency (UHF) for communication between the VIT and GNSS collar, which had two-way communication using Iridium satellites. A change (Brand 1) or drop (Brand 2) in temperature of more than 3 °C and inactivity triggered the VIT to communicate an expelled alert to the collar, which transmitted the birth alert information via Iridium (device ID, date, time and geolocation of the GNSS collar at expulsion). Cows and calves were tracked in the paddock following a birth alert to assess their health and status. Overall, true birth alerts occurred in only 27.6% of devices. Cows remained active on the day of calving travelling 5.54 ± 4.11 and 5.00 ± 2.80 km/day compared to 6.45 ± 2.79 and 6.12 ± 2.30 km/d on days when calving did not occur for Trial 1 and 2, respectively (mean ± SD). Average activity of the accelerometer X- and Y-axis on calving day was reduced by 15%–20% compared to other days in Trial 1 (p < 0.05) but not in Trial 2 (p > 0.05). Results suggest that these two birth alert systems are not suitable for use in extensive systems and the further development of the technology is required. Cows in the current trials remained active on the day of, and after, calving, indicating that a faster, real-time alert system and communication protocol would be required to achieve the aim of finding newborn calves.

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