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11.
We demonstrate a simple method to tune and pattern the wettability of polydimethylsiloxane (PDMS) to generate microfluidic mimics of heterogeneous porous media. This technique allows one to tailor the capillary forces at different regions within the PDMS channel to mimic multi-phase flow in oil reservoirs. In this method, UV-ozone treatment is utilized to oxidize and hydrophilize the surface of PDMS. To maintain a stable surface wettability, the oxidized surfaces are immersed in water. Additionally, the use of a photomask makes it convenient to pattern the wettability in the porous media. A one-dimensional diffusive reaction model is established to understand the UV-ozone oxidation as well as hydrophobic recovery of oxidized PDMS surfaces. The modeling results show that during UV-ozone, surface oxidation dominates over diffusion of low-molecular-weight (LMW) species. However, the diffusivity of LMW species plays an important role in wettability control of PDMS surfaces. 相似文献
12.
PHOTOCONTROL OF LEAF SENESCENCE 总被引:4,自引:0,他引:4
13.
Bishnu P. Biswal Sreeramulu Valligatla Mingchao Wang Tanmay Banerjee Nabil A. Saad Bala Murali Krishna Mariserla Naisa Chandrasekhar Daniel Becker Matthew Addicoat Irena Senkovska Reinhard Berger D. Narayana Rao Stefan Kaskel Xinliang Feng 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(21):6970-6974
Covalent organic frameworks (COFs) have garnered immense scientific interest among porous materials because of their structural tunability and diverse properties. However, the response of such materials toward laser‐induced nonlinear optical (NLO) applications is hardly understood and demands prompt attention. Three novel regioregular porphyrin (Por)‐based porous COFs—Por‐COF‐HH and its dual metalated congeners Por‐COF‐ZnCu and Por‐COF‐ZnNi—have been prepared and present excellent NLO properties. Notably, intensity‐dependent NLO switching behavior was observed for these Por‐COFs, which is highly desirable for optical switching and optical limiting devices. Moreover, the efficient π‐conjugation and charge‐transfer transition in ZnCu‐Por‐COF enabled a high nonlinear absorption coefficient (β=4470 cm/GW) and figure of merit (FOM=σ1/σo, 3565) value compared to other state‐of‐the‐art materials, including molecular porphyrins (β≈100–400 cm/GW), metal–organic frameworks (MOFs; β≈0.3–0.5 cm/GW), and graphene (β=900 cm/GW). 相似文献
14.
Sunit Kumar Sahoo Gyanada Sankar Dash Satyajeet Biswal Prasanta Kumar Biswal 《Journal of Dispersion Science and Technology》2019,40(3):464-475
The current work designed to fabricate and evaluate self-nanoemulsfying oil formulations (SNEOFs) of Efavirenz (Efz) a BCS class II drug with the objective of increasing its solubility as well as in vitro dissolution rate for improvisation of bioavailability. Preliminary screening of drug which includes solubility, emulsifying ability and ternary phase diagrams was carried out to fabricate SNEOFs. Various thermodynamic stability studies were exercised to find out the stable SNEOFs. Robustness to dilution, % transmittance and turbidity, droplet size analysis, TEM study, cloud point measurement, viscosity and refractive index were executed on the stable SNEOFs to characterize the delivery system. FTIR study was adopted for the compatibility of the additives with the drug. In vitro release profiles of SNEOFs compared with Efz, percent dissolution efficiency (DE) and dissolution half-life (t50) were evaluated. A low percent DE (30.12%) and high t50 was obtained for Efz whereas all SNEOFs showed a DE of greater than 78.48% and less than 9?min t50. The optimized SNEOFs (F8) demonstrated a significant (p?<?0.05) increase in bioavailability over Efz. Thus the designed optimized delivery system could be instrumental in increasing aqueous solubility of Efz, improving its release performance and enhancement of oral absorption. 相似文献
15.
High resolution laser induced fluorescence spectrum of jet-cooled SO(2) is recorded toward the blue side of the Clement's A-Band in the region of 314-319 nm. Time resolved fluorescence measurements have been carried out for all the prominent peaks in this region. Most of the peaks exhibited double exponential decay profiles. Some of the rovibronic bands exhibited quantum beats with strong quantum beats observed at 315.261 and 315.271 nm. This is the first observation of quantum beats in SO(2) in the absence of any external magnetic or electric fields. The decay profiles of the beating rovibronic bands were fitted using a four-level model by least-squares fitting method. The fitting shows that all the measured bands were double exponential with a similar first lifetime of approximately 3 mus and a varying second lifetime of the order of 1 micros-100 ns with a beating frequency of approximately 1 MHz. These quantum beats, in the absence of any external field, indicate rotational level mixing between the A (1)A(2) and the B (1)B(1) vibronic states which are near resonant due to the high density of states of these two states. 相似文献
16.
J. Ray A.K. Biswal S. Acharya V. Ganesan D.K. Pradhan P.N. Vishwakarma 《Journal of magnetism and magnetic materials》2012
Bismuth ferrite is doped with a dilute concentration of cobalt, BiFe1−XCoXO3; X=0, 0.01, 0.02 is prepared by sol-gel auto combustion technique. X-ray diffraction data refined via Reitveld method shows single phase and shrinkage in cell volume for Co doped BiFeO3. Various magnetic ground states viz. superparamagnetic, glassy antiferromagnetic and glassy ferrimagnetic behavior is observed for X=0, 0.01, 0.02, respectively. A first-order magnetic transition is observed in the Arrott plot data of cobalt doped BiFeO3. Possibility of thermally induced magnetic transition is also seen in the magnetization data of cobalt doped BiFeO3. A model based on the existing spinoidal cyclic arrangement of spins is proposed to explain the observed data. Finally, a very dilute concentration of Co+3 in BiFeO3 is found sufficient to tailor the magnetic properties. 相似文献
17.
K. L. Mahanta S. K. Biswal P. K. Sahoo M. C. Adhikary 《International Journal of Theoretical Physics》2012,51(5):1538-1544
We have constructed Bianchi type-III cosmological model with strange quark matter attached to the string cloud in Barber’s
(Gen. Relativ. Gravit. 14:117, 1982) second self-creation theory of gravitation which is inflationary. Further it is obtained that the theory leads to Einstein
theory at initial epoch and at infinite future. 相似文献
18.
Biswal Rasmita Nayak Debasis Janakiraman S. Chaudhary N. Vijay Prakash Ghosh Sudipto Adyam Venimadhav 《Journal of Solid State Electrochemistry》2021,25(2):561-573
Journal of Solid State Electrochemistry - The tin oxide (SnO2) thin films have been prepared by the pulsed laser deposition (PLD) at deposition temperatures (Td) ranging from 300 to... 相似文献
19.
Dr. K. Justice Babu Gurpreet Kaur Liza Biswal Prof. Dr. Goutam De Prof. Dr. Hirendra N. Ghosh 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(2):683-691
CsPbBr3 nanocrystals (NCs) encapsulated in a transparent polystyrene (PS) fiber matrix (CsPbBr3@PS) have been synthesized to protect the NCs. The ultrafast charge delocalization dynamics of the embedded NCs have been demonstrated, and the results are compared with the pristine CsPbBr3 in toluene. The electrospinning method was employed for the preparation of CsPbBr3@PS fibers by using a polystyrene solution doped with pre-synthesized CsPbBr3 and characterized by XRD, HRTEM, and X-ray photoelectron spectroscopy (XPS). Energy level diagrams of CsPbBr3 and PS suggest that CsPbBr3@PS fibers make a type I core–shell structure. The carrier cooling for CsPbBr3@PS fibers is found to be much slower than pure CsPbBr3 NCs. This observation suggests that photoexcited electrons from CsPbBr3 NCs get delocalized from the conduction band of the perovskite to lowest unoccupied molecular orbital (LUMO) of the PS fiber matrix. The CsPbBr3@PS fibers possess remarkable stability under ambient conditions as well as in water over months. The clear understanding of charge carrier relaxation dynamics of CsPbBr3 confined in PS fibers could help to design robust optoelectronic devices. 相似文献
20.
Chemically Stable Covalent Organic Framework (COF)‐Polybenzimidazole Hybrid Membranes: Enhanced Gas Separation through Pore Modulation
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Bishnu P. Biswal Harshal D. Chaudhari Prof. Dr. Rahul Banerjee Prof. Dr. Ulhas K. Kharul 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(14):4695-4699
Highly flexible, TpPa‐1@PBI‐BuI and TpBD@PBI‐BuI hybrid membranes based on chemically stable covalent organic frameworks (COFs) could be obtained with the polymer. The loading obtained was substantially higher (50 %) than generally observed with MOFs. These hybrid membranes show an exciting enhancement in permeability (about sevenfold) with appreciable separation factors for CO2/N2 and CO2/CH4. Further, we found that with COF pore modulation, the gas permeability can be systematically enhanced. 相似文献