The Manufacture of Spherical WC Powder in Plasma

2013 ◽  
Vol 774-776 ◽  
pp. 1258-1261
Author(s):  
Wei Huang ◽  
Zi Ming Chen ◽  
Yong Liu ◽  
Fu Jun Shang ◽  
Ji Hong Su ◽  
...  
Keyword(s):  
Particle Size ◽  
Plasma Treatment ◽  
Oxygen Content ◽  
Spherical Powder ◽  
Induction Plasma ◽  
Manufacture Technology ◽  
Plasma Method ◽  
Before And After

The manufacture technology of spherical WC powder has been studied by using of induction plasma. We can get spherical powder above 85% in the powder through changing several parameters. And the hall flow-ability, the oxygen content , particle size of powder before and after plasma treatment have been compared. The results were shown that oxygen contents was deduced markedly, and the plasma method can control the particle size easily.

The stability of dislocation networks under various oxygen-doping conditions in superconducting Bi2Sr2CaCu2Oy single crystals and their influence on the flux pinning properties

1994 ◽  
Vol 52 ◽  
pp. 802-803
Author(s):  
Y. Feng ◽  
X. Y. Cai ◽  
R. J. Kelley ◽  
D. C. Larbalestier
Keyword(s):  
Single Crystals ◽  
Oxygen Content ◽  
Basal Plane ◽  
Flux Pinning ◽  
Pinning Centers ◽  
Before And After ◽  
Anomalous Peak ◽  
Basal Plane Dislocation ◽  
The Stability ◽  
Further Development

The issue of strong flux pinning is crucial to the further development of high critical current density Bi-Sr-Ca-Cu-O (BSCCO) superconductors in conductor-like applications, yet the pinning mechanisms are still much debated. Anomalous peaks in the M-H (magnetization vs. magnetic field) loops are commonly observed in Bi2Sr2CaCu2Oy (Bi-2212) single crystals. Oxygen vacancies may be effective flux pinning centers in BSCCO, as has been found in YBCO. However, it has also been proposed that basal-plane dislocation networks also act as effective pinning centers. Yang et al. proposed that the characteristic scale of the basal-plane dislocation networksmay strongly depend on oxygen content and the anomalous peak in the M-H loop at ˜20-30K may be due tothe flux pinning of decoupled two-dimensional pancake vortices by the dislocation networks. In light of this, we have performed an insitu observation on the dislocation networks precisely at the same region before and after annealing in air, vacuumand oxygen, in order to verify whether the dislocation networks change with varying oxygen content Inall cases, we have not found any noticeable changes in dislocation structure, regardless of the drastic changes in Tc and the anomalous magnetization. Therefore, it does not appear that the anomalous peak in the M-H loops is controlled by the basal-plane dislocation networks.

Effect of particle size and delignification on the rate of digestion of hemicellulose and cellulose by cellulase in mature pangola grass stems

1983 ◽  
Vol 34 (3) ◽  
pp. 241 ◽  
Author(s):  
CW Ford
Keyword(s):  
Particle Size ◽  
Cell Walls ◽  
Trichoderma Viride ◽  
Structural Features ◽  
Cell Wall Polysaccharides ◽  
Particle Size Reduction ◽  
Digitaria Decumbens ◽  
Hemicellulose Degradation ◽  
Before And After ◽  
The Difference

Stem cell walls of pangola grass (Digitaria decumbens) were ground to two particle sizes (c. 1 and 0.1 mm diameter), and incubated with cellulase (ex. Trichoderma viride) for varying times before and after delignification. Total cell walls finely ground (0.1 mm) with a Spex Shatterbox mill were initially degraded more rapidly (to 24 h) than delignified 1 mm particles. Thereafter the delignified material was solubilized to a greater extent. Subsequent specific determinations of cell wall polysaccharides indicated that delignification increased the rate of hemicellulose degradation to a greater extent than did particle size reduction, whereas the opposite was found for cellulose. The difference between delignified and Spex-ground residues, in terms of the amount of polysaccharide digested, was much greater for cellulose than hemicellulose. It is concluded that structural features play a more important role in limiting cellulase degradation of cellulose than does association with lignin, the reverse being so for hemicellulose.

scholarly journals Experimental Investigation of Wave Velocity-Permeability Model for Granite Subjected to Different Temperature Processing

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Guanghui Jiang ◽  
Jianping Zuo ◽  
Teng Ma ◽  
Xu Wei
Keyword(s):  
Particle Size ◽  
High Temperature ◽  
Wave Velocity ◽  
Pore Fluid ◽  
Rock Matrix ◽  
Permeability Model ◽  
Wave Velocities ◽  
Before And After ◽  
Different Temperatures ◽  
Increasing Temperature

Understanding the change of permeability of rocks before and after heating is of great significance for exploitation of hydrocarbon resources and disposal of nuclear waste. The rock permeability under high temperature cannot be measured with most of the existing methods. In this paper, quality, wave velocity, and permeability of granite specimen from Maluanshan tunnel are measured after high temperature processing. Quality and wave velocity of granite decrease and permeability of granite increases with increasing temperature. Using porosity as the medium, a new wave velocity-permeability model is established with modified wave velocity-porosity formula and Kozeny-Carman formula. Under some given wave velocities and corresponding permeabilities through experiment, the permeabilities at different temperatures and wave velocities can be obtained. By comparing the experimental and the theoretical results, the proposed formulas are verified. In addition, a sensitivity analysis is performed to examine the effect of particle size, wave velocities in rock matrix, and pore fluid on permeability: permeability increases with increasing particle size, wave velocities in rock matrix, and pore fluid; the higher the rock wave velocity, the lower the effect of wave velocities in rock matrix and pore fluid on permeability.

scholarly journals About a possibility of increasing the adhesion strength between mineral glass and polymeric binder under radio-frequency induction plasma treatment

2017 ◽  
Vol 789 ◽  
pp. 012033
Author(s):  
I S Miftakhov ◽  
A V Trofimov ◽  
A I Nagmutdinova ◽  
E F Voznesensky ◽  
F S Sharifullin ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Plasma Treatment ◽  
Adhesion Strength ◽  
Polymeric Binder ◽  
Induction Plasma

Surface Modification of Si Field Emitter Arrays for Vacuum Sealing

2000 ◽  
Vol 621 ◽  
Author(s):  
M. Nagao ◽  
H. Tanabe ◽  
T. Kobayashi ◽  
T. Matsukawa ◽  
S. Kanemaru ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Vacuum Packaging ◽  
Field Emitter ◽  
Vacuum Sealing ◽  
Field Emitter Arrays ◽  
Vacuum Microelectronics ◽  
Field Emission Displays ◽  
Before And After ◽  
Heating Treatment ◽  
Field Emitter Array

ABSTRACTVacuum packaging is a very important issue for vacuum microelectronics devices, especially for field emission displays. Emission current from the field emitter array (FEA), however, is known to decrease significantly after the vacuum packaging process. The current decrease is caused by heating treatment in the vacuum sealing process. In the present paper, the effect of the heating treatment on Si FEA was investigated and CHF3 plasma treatment was proposed for avoiding the problem. The Si FEA was exposed to plasma for 15sec and emission characteristics were measured before and after the vacuum sealing process using frit. It was confirmed that CHF3 plasma treatment was very effective for avoiding the emission degradation of the Si FEA. Details of the heating damage and CHF3 plasma treatment are described.

Investigation of the properties of knitted woolen fabrics treated with oxygen low-temperature plasma for sportswear applications

2021 ◽  
pp. 004051752110306
Author(s):  
Honglian Cong ◽  
Boyu Zhao ◽  
Hao Han ◽  
Xuliang Yu
Keyword(s):  
Low Temperature ◽  
Plasma Treatment ◽  
Moisture Absorption ◽  
Mapping Method ◽  
Function Evaluation ◽  
Low Temperature Plasma ◽  
Temperature Plasma ◽  
Wool Fibers ◽  
Before And After ◽  
Concentration Mapping

Nine groups of knitted woolen fabrics for sportswear with different technical characteristics were treated with oxygen low-temperature plasma, and the changes in the surface morphology and chemical composition of wool fibers before and after plasma treatment, as well as the changes in the applicability indexes of knitted woolen fabrics, were studied. Finally, the comfort performance of the fabrics was evaluated by combining the concentration mapping method and the function evaluation value method. The analysis found that the surface scales of wool fibers were seriously etched after oxygen low-temperature plasma treatment, and the anti-felting, bursting strength and moisture absorption of the knitted woolen fabrics were improved. At the same time, the quick-drying index of the fabric has also been improved to a certain extent. This research provides a basis for the development of knitted woolen fabric for sportswear with excellent performance.

scholarly journals Application of Waterborne Acrylic and Solvent-Borne Polyester Coatings on Plasma-Treated Fir (Abies alba M.) Wood

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 370
Author(s):  
Hadi Gholamiyan ◽  
Behnam Gholampoor ◽  
Reza Hosseinpourpia
Keyword(s):  
Plasma Treatment ◽  
Treated Wood ◽  
Abies Alba ◽  
Untreated Wood ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Accelerated Weathering ◽  
Water Contact ◽  
Before And After ◽  
Carbon Dioxide Co2

This research investigates the effect of plasma treatment with air, nitrogen (N2), and carbon dioxide (CO2) gases on the performance of waterborne (acrylic) and solvent-borne (polyester) coated fir (Abies alba M.) wood samples. The properties of the plasma-coated samples were analyzed before and after exposure to accelerated weathering and compared with those of untreated and solely treated ones. According to pull-off testing, the coating adhesion of the wood samples was considerably improved by plasma treatment, and obvious differences were observed between different plasma gases. The effect was more pronounced after the weathering test. Similar results were obtained for the abrasion resistance of the samples. The water contact angle measurement illustrated more hydrophilic character in the solely plasma-treated wood in comparison with the untreated wood. The application of coatings, however, strongly improved its hydrophobic character. The performances of waterborne and solvent-borne coatings on plasma-treated wood were comparable, although slightly better values were obtained by the waterborne system. Our results exhibit the positive effect of plasma treatment on coating performances and the increased weather resistance of the waterborne and solvent-borne coating systems on plasma-treated wood.

Surface Modification of Cellulose Membrane by Air Plasma Treatment

2013 ◽  
Vol 770 ◽  
pp. 112-115
Author(s):  
Nawal Binhayeeniyi ◽  
Adinan Jehsu ◽  
Mancharee Sukpet ◽  
Safitree Nawae
Keyword(s):  
Surface Modification ◽  
Plasma Treatment ◽  
Surface Modifications ◽  
Contact Angles ◽  
Cellulose Membrane ◽  
Air Plasma ◽  
Before And After ◽  
Cellulose Membranes ◽  
Hydrophilic Membranes ◽  
Air Plasma Treatment

Low-temperature air plasma was used to treat the cellulose membranes by varying the period of time from 10 to 30 minutes. The surfaces of membranes were changed from hydrophobic to hydrophilic membranes. The contact angles of treated membranes were increased when increasing time to treat. The surface modifications of membrane before and after treated were characterized by SEM. It is shown that air plasma treatment is used to improve the roughness. The dielectric property was also studied.

scholarly journals The Effect of Exercise on Oxygen Content in Anemic Patients With Chronic Obstructive Pulmonary Disease

2018 ◽  
Vol 12 ◽  
pp. 117954841879648
Author(s):  
Ahmet Sinan Copur ◽  
Hannan Dogar ◽  
Zhang Chao ◽  
Leandra Wallace ◽  
Kevin Henegar ◽  
...  
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Pulmonary Disease ◽  
Oxygen Content ◽  
T Test ◽  
Walking Distance ◽  
Chronic Obstructive ◽  
Continuous Variables ◽  
Obstructive Pulmonary Disease ◽  
Arterial Blood ◽  
Before And After

Background: Anemia is reported in one-third of the patients with chronic obstructive pulmonary disease (COPD). Anemia, by decreasing oxygen content, can be a contributing factor for hypoxemia. We determined to find whether anemia causes more prominent hypoxia by decreasing the total oxygen content after exercise in anemic patients with COPD. Methods: Stable moderate-to-severe COPD patients with and without anemia were recruited. Arterial blood gas analyses were performed on room air before and after a 6-minute walking test (6MWT). Walking distance, oxygen saturation, and heart rate were recorded in each case before and after the 6MWT. Pulmonary function test measurements and other data were obtained from the chart. The mean and standard deviations were calculated for continuous variables. The independent t-test and Kruskal-Wallis test were performed for numerical covariate and univariate analyses. The paired t-test was used for the analyses of data before and after exercise. Results: A total of 24 male patients were included in the study; 12 of which were anemic. The oxygen content was decreased in the anemic group (15.22 ± 1.28 vs 15.07 ± 1.22) after exercise, but it was not significant. In the non-anemic group, no oxygen content decrease was observed after exercise (18.83 ± 1.41 vs 18.9 ± 1.37). Interestingly, the Spo2, but not Sao2, was significantly lower after exercise in anemic patients with COPD (93.46% ± 5.06% vs 88.20% ± 6.35% before and after exercise, respectively). Conclusions: Anemia does not cause more prominent hypoxemia after exercise in patients with COPD. However, the recorded Spo2 levels were significantly lower after exercise in the anemic patients with COPD.

scholarly journals Polyimide Surface Modification Using He-H2O Atmospheric Pressure Plasma Jet-Discharge Power Effect

Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 662
Author(s):  
Essam Abdel–Fattah ◽  
Mazen Alshaer
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Plasma Treatment ◽  
Atmospheric Pressure ◽  
Atmospheric Pressure Plasma ◽  
Plasma Jet ◽  
Discharge Power ◽  
Force Microscopy ◽  
Before And After ◽  
Power Effect

The atmospheric pressure He- H 2 O plasma jet has been analyzed and its effects on the Kapton polyimide surface have been investigated in terms of discharge power effect. The polyimide surfaces before and after plasma treatment were characterized using atomic force microscopy (AFM), X-ray photoelectrons spectroscopy (XPS) and contact angle. The results showed that, increasing the discharge power induces remarkable changes on the emission intensity, rotational and vibrational temperatures of He- H 2 O plasma jet. At the low discharge power ≤5.2 W, the contact angle analysis of the polyimide surface remarkably decrease owing to the abundant hydrophilic polar C=O and N–C=O groups as well as increase of surface roughness. Yet, plasma treatment at high discharge power ≥5.2 W results in a slight decrease of the surface wettability together with a reduction in the surface roughness and polar groups concentrations.

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