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71.
Zoobia Ameer Anna Grazia Monteduro Silvia Rizzato Anna Paola Caricato Maurizio Martino I. C. Lekshmi Abhijit Hazarika Debraj Choudhury Elisabetta Mazzotta Cosimino Malitesta Vittorianna Tasco D. D. Sarma Giuseppe Maruccio 《Journal of Materials Science: Materials in Electronics》2018,29(9):7090-7098
The increasing constraints in the miniaturization of modern electronic devices is driving the search for new high-k dielectric materials. Rare-earth transition metal oxides are very interesting because of the large values of dielectric constant observed in bulk samples. Here, we report on a comparison among the dielectric properties of yttrium copper titanate (YCTO) thin films and those of commonly used dielectrics such as SiO2 and MgO, grown in similar device structures. The YCTO permittivity was found to depend strongly on the oxygen pressure during deposition and can reach values even higher than those reported in bulk YCTO with good performances in terms of losses. 相似文献
72.
In this work, we report on structural, optical, photocatalytic and nitrogen adsorption–desorption characteristics of \(\hbox {WS}_{2 }\) nanosheets developed via a hydrothermal route. X-ray diffraction (XRD) studies have revealed a hexagonal crystal structure, whereas nanodimensional sheets are apparently observed in scanning and transmission electron microscopy (SEM and TEM) micrographs. As compared to the bulk counterpart, the \(\hbox {WS}_{2}\) nanosheets exhibited a clear blue shift. Through Brunauer–Emmett–Teller (BET) surface area analysis, average surface area, pore volume and pore size of the NSs were calculated as 211.5 \(\hbox {m}^{2}~\hbox {g}^{-1}\), 0.433 cc \(\hbox {g}^{-1}\) and 3.8 nm, respectively. The photocatalytic activity of the \(\hbox {WS}_{2}\) nanosheets was also examined with malachite green (MG) as the target dye under both UV and day light (visible) illumination conditions. Accordingly, a degradation efficiency as high as 67.4 and 86.6% were witnessed for an irradiation time duration of 60 min. The nano-\(\hbox {WS}_{2}\) systems have immense potential in optoelectronics, solid-lubrication and other next generation elements. 相似文献
73.
During power system restoration, it is necessary to check the phase angle between two buses before closing circuit breakers to connect a line between them. In case of large standing phase angle (SPA) difference the synchrocheck relay does not allow closing of the breaker for this line. Therefore, this SPA has to be reduced before attempting to connect the line. In this paper a new and fast method for reducing SPA is presented. For this purpose, the standing phase angle difference between two specific buses is represented in terms of sensitivity factors associated with the change in real power injections at the buses. The proposed method will act as a direct help for reducing excessive SPA difference between two buses to an acceptable limit 相似文献
74.
Dhamodaran Arunbabu Mousumi Hazarika Somsankar Naik Tushar Jana 《Bulletin of Materials Science》2009,32(6):633-641
We have synthesized highly charged, crosslinked poly (styrene-co-divinylbenzene-co-sulfopropyl methacrylate) copolymer colloidal particles using emulsion polymerization. The effects of concentration of the
emulsifier and the initiator on the particle size and the charge density of the colloidal particles are studied. Colloidal
particle size is highly dependent upon the concentration of the emulsifier and the initiator. The colloidal particle diameter
decreases with increasing concentration of the emulsifier and increases with increasing concentration of the initiator in
the polymerization mixture. Number of particles, surface charge density and charges per particle are also functions of both
the emulsifier and the initiator concentration. The surface charge density and the number of charges per sphere increase with
increasing particle diameter. These copolymer colloid particles self assemble readily and diffract visible light. Polymer
hydrogel imbibed with these colloids shows the light diffraction. 相似文献
75.
An immunoassay based technique is used for the detection of psychoactive substances in the sweat deposited within fingermarks of a narcotic drug user. Magnetic particles functionalized with antimorphine and antibenzoylecgonine antibodies were used for the detection of a metabolite of heroin (morphine) and a metabolite of cocaine (benzoylecgonine), respectively. The drug metabolites were detected individually as well as simultaneously from a single fingermark. The images of the fingermarks obtained using brightfield and fluorescence microscopy were of high evidential quality with resolution to enable identification of an individual in addition to providing information on drug usage. 相似文献
76.
Melamine formaldehyde‐furfuryl alcohol (MFFA) copolymer was prepared and impregnated into softwood Ficus hispida in combination with crosslinking agent and montmorillonite (MMT) under vacuum condition. Different crosslinkers namely n‐methylol acrylamide, (NMA), 2‐hydroxyethyl methacrylate (HEMA) and 1,3‐dimethylol‐4,5‐dihydroxyethyleneurea (DMDHEU) were used for evaluation of properties of the prepared composites. Nuclear magnetic resonance (NMR) and fourier transform infrared spectroscopy (FTIR) studies confirmed the formation of MFFA copolymer, NMA, and DMDHEU crosslinkers. X‐ray diffractometry (XRD) and FTIR studies were used to characterize the nanocomposites. The incorporation of MMT decreased the crystallinity of wood composites as revealed by XRD study. Maximum interaction was found in wood samples treated with MFFA/(NMA+HEMA+DMDHEU)/MMT as shown by FTIR study. The incorporation of MMT into the wood polymer composite was revealed by transmission electron microscopy study. Thermal stability and flammability were checked by thermogravimetric analyzer and limiting oxygen index instrument. Wood treated with MFFA, blended crosslinker and MMT exhibited higher dimensional stability, lower water uptake (%), enhanced chemical resistance, and better mechanical properties (flexural, tensile, and hardness). SEM study indicated the presence of polymer and MMT in the void spaces of wood. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers 相似文献
77.
Das B Hazarika P Saikia G Kalita H Goswami DC Das HB Dube SN Dutta RK 《Journal of hazardous materials》2007,141(3):834-841
A traditional method for removal of iron from ground water by using ash has been systematically investigated. Ashes from five different sources, viz., banana rind, banana pseudostem, banana leaf, rice husk and bamboo has been studied. The principle applied is enhanced precipitation of iron at high pH caused by ash. The study included laboratory analysis of some relevant chemical parameters of the ashes and the efficiency of the ashes in removing iron from prefabricated water with respect to quantity of ash and corresponding increase in pH of water. The ash of banana pseudostem has been found to be most suitable for removal of iron. A low-cost and easily made iron removal system for household use has been designed and tested in the laboratory. The ash of banana pseudostem has been found to remove iron to below 0.3ppm without increasing the pH above the acceptable limit. The optimum values of the different parameters for removal of iron are 200-300mgl(-1) ash, 1.0lh(-1) flow rate and 1h of contact time with ash for groundwater having [Fe] of about 2.20ppm. The amount of ash can be increased for groundwater having higher [Fe] and can be decreased gradually during continuous use of the system. Acceptability of the method has been examined based on chemical analysis of the treated water. Increase in the essential minerals such as Ca, K has been observed in the water after treatment. The designed iron removing system is expected to be suitable for household use. 相似文献
78.
Optimisation of withered leaf moisture during the manufacture of black tea based upon theaflavins fractions 总被引:1,自引:0,他引:1
Santanu Sabhapondit Pradip Bhattacharyya Lakshi P. Bhuyan Mridul Hazarika Bhabesh Ch Goswami 《International Journal of Food Science & Technology》2014,49(1):205-209
A study was conducted to see the effect of different moisture content of withered leaf on the activity of oxidative enzymes polyphenoloxidase (PPO) and peroxidase (PO) and on the formation of theaflavins (TFs) and thearubigins (TRs). Six commercially popular cultivars TV1, TV7, TV9, TV23, TV26 and T.3E/3 of Assam, India, were processed in four different moisture levels (72%, 70%, 68% and 65%). Significant reduction in PPO and PO enzymes, TFs, TRs and theaflavin digallate equivalent was observed with the decrease in moisture content of withered leaf. The TFs (0.83–5.4 mg g?1) and TRs (23–107 mg g?1) fractions were lowest at moisture level 65 ± 1%. Of the six cultivars studied, better quality of black tea was obtained for cultivar TV1, TV9 and TV23 at 70 ± 1% moisture content, while for TV7 and TV26, it was 68 ± 1%. Withered leaf moisture content should be carefully chosen to obtain the better quality tea from specific cultivar. 相似文献
79.
Groundwater Drought in the Northwestern Districts of Bangladesh 总被引:1,自引:0,他引:1
Prolonged absence of groundwater within the operating range of shallow tube-wells during dry season is a common problem in the northwestern districts of Bangladesh in the recent years. In this paper, groundwater scarcity and drought in three northwestern districts of Bangladesh have been investigated. The Cumulative Deficit approach from a threshold groundwater level has been used for the computation of severity of groundwater droughts. Monthly groundwater fluctuation data collected from 85 sites is used for the study. The study shows that groundwater scarcity in 42% area is an every year phenomenon in the region. Analysis of groundwater hydrographs and rainfall time-series reveals that ever increasing groundwater extraction for irrigation in the dry season and recurrent droughts are the causes of groundwater level drop in the region. 相似文献