排序方式: 共有28条查询结果,搜索用时 0 毫秒
1.
Langmuir probe measurements of radio frequency (RF) magnetic pole enhanced inductively coupled (MaPE-ICP) argon plasma were accomplished to obtain the electron number densities and electron temperatures. The measurements were carried out with a fixed RF frequency of 13.56 MHz in a pressure range of 7.5 mTorr to 75 mTorr at an applied RF power of 10 W and 100 W. These results are compared with a global (volume average) model. The results show good agreement between theoretical and experimental measurements. The electron number density shows an increasing trend with both RF power and pressure while the electron temperature shows decreasing trend as the pressure increases. The difference in the plasma potential and floating potential as a function of electron temperature measured from the electrical probe and that obtained theoretically shows a linear relation with a small difference in the coefficient of proportionality. The intensity of the emission line at 750.4 nm due to 2p 1 → 1s 2 (Paschen’s notation) transition closely follows the variation of n e with RF power and filling gas pressure. Measured electron energy probability function (EEPF) shows that electron occupation changes mostly in the high-energy tail, which highlights close similarity of 750.4 nm argon line to n e . 相似文献
2.
AMIR FEREIDOUNI LOTFABADI MOHD HASBULLAH IDRIS ALI OURDJINI MOHAMMED RAFIQ ABDUL KADIR SAEED FARAHANY HAMID REZA BAKHSHESHI-RAD 《Bulletin of Materials Science》2013,36(6):1103-1113
The thermal parameters of Mg–xZn cast alloys with 0·5–9 wt% Zn were evaluated by using computer aided cooling curve thermal analysis (CA–CCTA), whereas the corrosion behaviour was investigated by potentiodynamic polarization and immersion tests. Thermal analysis results revealed that the dendrite coherency temperature (T DCP ) decreased from 642·2 to 600 °C with the addition of Zn from 0·5 to 9 wt%. The liquid fraction at coherency point ( ${f}_{ L}^{ DCP}$ ) increased by 72% when Zn was increased up to 9 wt%. MgZn intermetallic phase was observed in samples with <3 wt% Zn. At higher percentages of Zn, the Mg 51Zn 20 intermetallic phase was also detected in addition to α-Mg and MgZn by first derivative cooling curves under non-equilibrium solidification. All these phases were observed along the grain boundary when Zn was rejected from the solid/liquid interface and enriched in the triple conjunction of grain boundary. The grain size decreased from 185·2 to 71·5 μm when Zn content was increased. The addition of Zn content had a significant effect on the corrosion rate and the corresponding mechanisms. The corrosion rate decreased from 2·1 to 1·81 mmpy as Zn content increased from 0·5 to 3 wt%; afterwards, however, this value increased with further increase of Zn. Mg–3Zn also had the lowest degradation rate and highest corrosion resistance which can be fully utilized for biodegradable orthopedic applications. 相似文献
3.
Protein concentrates and isolates from sunflower (Helianthus annuus L.), essentially free of polyphenols and/or low in phytate, were prepared from dehulled seeds by a sequential extraction procedure using organic solvents, such as hexane for defatting and acidic butanol for removing polyphenols. Phytate was removed by aqueous extraction and separation at acidic and/or alkaline conditions, depending on the relative solubility of the protein and phytate. Reduced-phytate concentrates and isolates developed off-colors unless the polyphenol concentration was less than 0.05%. The protein solubility profile of the reduced-phytate products was much better than that of the defatted meal, especially below the isoelectric point. 相似文献
4.
5.
6.
A. SAEED A. W. KHAN M. SHAFIQ F. JAN M. ABRAR M. ZAKA-UL-ISLAM M. ZAKAULLAH 《等离子体科学和技术》2014,16(4):324-328
Optical emission spectroscopy is used to investigate the nitrogen-hydrogen with trace rare gas (4% Ar) plasma generated by 50 Hz pulsed DC discharges. The filling pressure varies from 1 mbar to 5 mbar and the current density ranges from 1 mA·cm −2 to 4 mA·cm −2 . The hydrogen concentration in the mixture plasma varies from 0% to 80%, with the objective of identifying the optimum pressure, current density and hydrogen concentration for active species ([N] and [N 2 ]) generation. It is observed that in an N 2 -H 2 gas mixture, the concentration of N atom density decreases with filling pressure and increases with current density, with other parameters of the discharge kept unchanged. The maximum concentrations of active species were found for 40% H 2 in the mixture at 3 mbar pressure and current density of 4 mA·cm −2 相似文献
7.
Molybdate sulfuric acid (MSA) has been demonstrated to be an efficient and reusable catalyst for the synthesis of quinoxaline and phenazine derivatives based on the condensation of 1,2-diketones and o-pheneylenediamines in ethanol as solvent at room temperature. Also, some novel polycyclic phenazines and quinoxalines are reported. The practical and simple method adopted in the present study led to very high yields of the products under mild conditions within short time intervals. 相似文献
8.
FAZLUR RAHMAN SHAMS TABREZ RAHAT ALI SAJJADUL KADIR AKAND MOHAMMED A. ALAIDAROUS MOHAMMED ALSAWEED BADER MOHAMMED ALSHEHRI SAEED BANAWAS ABDUR RUB ABDUL AZIZ BIN DUKHYIL 《Biocell》2021,45(6):1601-1610
Leishmaniasis is a vector-borne parasitic neglected tropical disease caused by a group of about 30 differentspecies of the genus Leishmania. It is transmitted by the bite of female phlebotomies sand fly. Three main clinicalmanifestations of leishmaniasis include cutaneous, visceral, and mucocutaneous leishmaniasis. Visceral leishmaniasis(VL) caused by Leishmania donovani, is an infection of reticuloendothelial system and fatal if untreated. Cholesterol,a sterol that is prominent in the mammalian cell membranes whereas stigmasterol and ergosterol are more prevalentin plants, yeast, and protozoa, respectively. Ergosterols which is absent in human being, is an important constituent ofparasite membrane. Sterol C-24 reductase (LdSR) enzyme catalyzes the final step in the ergosterol biosynthesis pathway.The inhibition of biosynthesis of ergosterol may lead to decreased cell viability and growth. Here, we performed themolecular docking-based virtual screening of a library of natural ligands against LdSR to identify a potential inhibitor tofight leishmaniasis. Capsaicin, prenyletin, flavan-3-ol, resveratrol, and gingerol showed the top binding affinity towardsLdSR. Based upon ADME properties and bioactivity score, gingerol showed the best lead-likeness and drug-likenessproperties. Hence, we further annotated its leishmanicidal properties. We found that gingerol inhibited the growth andproliferation of promastigotes as well as intra-macrophagic amastigotes. Gingerol exerted its antileishmanial actionthrough the induction of reactive oxygen species (ROS) in concentration-dependent manner. Gingerol induced ROS ledto apoptosis. Overall, this study described that gingerol would act as possible inhibitor to LdSR. 相似文献
9.
10.
BOTAN JAWDAT ABDULLAH QING JIANG MUSTAFA SAEED OMAR 《Bulletin of Materials Science》2016,39(5):1295-1302
This study investigates the effect of size on mass density and its subsequent influence on the other physical parameters of zirconia nanoparticles in the structural forms of cubic, tetragonal and monoclinic. The general equations for these calculations are established based on the variation of lattice parameter model and surface internal atoms ratio. The mass density of nanoparticles differs from the bulk value when particle size decreases. At a diameter of 4 nm, the mass density values of zirconia nanoparticles are 3.898, 3.626 and 3.488 g ? cm?3 compared to 6.25, 6.1 and 5.87 g? cm?3 for bulk cubic, tetragonal and monoclinic forms, respectively. These results indicate that the variation in mass density is largely due to the differences on their boundaries and the variation in lattice parameters. The calculated results agree well with the available experimental data for the monoclinic form structure of ZrO 2 nanoparticles. The relationship between mass density and melting temperature; and Debye temperature and cohesive energy are proposed. All these parameters have the same nanosize dependence in this regard. 相似文献