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排序方式: 共有554条查询结果,搜索用时 15 毫秒
31.
Solar Cells: Ab Initio Simulation of Charge Transfer at the Semiconductor Quantum Dot/TiO2 Interface in Quantum Dot‐Sensitized Solar Cells (Part. Part. Syst. Charact. 1/2015)
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32.
A. S. Singha Ashish Guleria Raj K. Rana 《International Journal of Polymer Analysis and Characterization》2014,19(4):318-331
Functional materials obtained from cellulosic biofibers have gained attention due to the growing demand for them in the field of wastewater remediation. In view of the technological significance of functionalized cellulosic biofibers in wastewater treatment, the present study is a green approach to functionalized cellulosic fibers through graft copolymerization under microwave irradiation. The grafted cellulosic polymers were subsequently subjected to heavy metal ion adsorption studies in order to assess their application in wastewater remediation. The effects of pH, contact time, temperature, and metal ion concentration were studied in batchwise adsorption experiments. The Langmuir, Freundlich, and Tempkin models were used to show the adsorption isotherms. The maximum monolayer capacities, q m. calculated using the Langmuir isotherm for Zn2+, Cd2+, and Pb2+ were found to be 37.79, 69.68, and 96.81 mg/g respectively. The thermodynamic parameter ΔH° and ΔG° values for metal ion adsorption on functionalized cellulosic fibers showed that adsorption process was spontaneous as well as exothermic in nature. 相似文献
33.
Confinement of CuII–Phthalocyanine in a Bioinspired Hybrid Nanoparticle‐Assembled Structure Yields Selective and Stable Epoxidation Catalysts
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Joydeb Manna Arlin Jose Amali Dr. Rohit Kumar Rana 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(27):8453-8457
Herein, we demonstrate that a bioinspired assembly of silica nanoparticles with polyamines as structure‐directing agents similar to that known for the biosilicification of diatoms can pave the way for the efficient encapsulation of sulfonated copper–phthalocyanine in a hybrid microcapsule structure, in which the organic component provides a capable environment for its catalytic activity in epoxidation reactions and the nanoassembled structure imparts stability. 相似文献
34.
Dr. Rakesh Chilivery Dr. Gousia Begum Vahinipathi Chaitanya Dr. Rohit Kumar Rana 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(21):8237-8242
A bio-inspired method is used to render controlled wrinkling surface patterns on supramolecular architectures assembled from polyoxometalate (POM) clusters. It involves a polyamine-multivalent anion interaction generating positively charged coacervates, which while dictating the assembly of POM into spherical structures further facilitate an interesting surface morphogenesis with wrinkling patterns. This spontaneous surface wrinkling depends on the type of multivalent anion and the pH. As the polyamine-anion interaction becomes stronger, the wrinkles turn denser with lesser depth, which eventually undergoes post-buckling to engender a complex surface pattern. Interestingly, the order of influence exerted by different anions on the morphology follows the Hofmeister series. Moreover, the mild synthesis conditions keep the functional POM units dispersed in the sphere with a structural transformability to their lacunary form. 相似文献
35.
Kubra Kahremanoglu Ezgi Rana Temel Tamara Ecem Korkut Atakan Arda Nalbant Bersu Batu Azer Caner Durucan Murvet Volkan Ezel Boyaci 《Journal of separation science》2020,43(9-10):1925-1933
Recently the connection between oxidative stress and various diseases, including cancer and Alzheimer's, attracts notice as a pathway suitable for diagnostic purposes. 8‐Oxo‐deoxyguanosine and 8‐oxo‐deoxyadenosine produced from the interaction of reactive oxygen species with DNA become prominent as biomarkers. Several methods have been developed for their determination in biofluids, including solid‐phase extraction and enzyme‐linked immunosorbent assays. However, still, there is a need for reliable and fast analytical methods. In this context, solid‐phase microextraction offers many advantages such as flexibility in geometry and applicable sample volume, as well as high adaptability to high‐throughput sampling. In this study, a solid‐phase microextraction method was developed for the determination of 8‐oxo‐deoxyguanosine and 8‐oxo‐deoxyadenosine in biofluids. The extractive phase of solid‐phase microextraction consisted of hydrophilic–lipophilic balanced polymeric particles. In order to develop a solid‐phase microextraction method suitable for the determination of the analytes in saliva and urine, several parameters, including desorption solvent, desorption time, sample pH, and ionic strength, were scrutinized. Analytical figures of merit indicated that the developed method provides reasonable interday and intraday precisions (<15% in both biofluids) with acceptable accuracy. The method provides a limit of quantification for both biomarkers at 5.0 and 10.0 ng/mL levels in saliva and urine matrices, respectively. 相似文献
36.
The European Physical Journal H - The widespread positivist approach of physics research in Italy at the turn of the XIX and XX centuries did not provide a fertile ground for the scientific debate... 相似文献
37.
Synthesis,characterization and role of zero-valent iron nanoparticle in removal of hexavalent chromium from chromium-spiked soil 总被引:3,自引:0,他引:3
Chromium is an important industrial metal used in various products/processes. Remediation of Cr contaminated sites present
both technological and economic challenges, as conventional methods are often too expensive and difficult to operate. In the
present investigation, Zero-valent iron (Fe0) nanoparticles were synthesized, characterized, and were tested for removal of Cr(VI) from the soil spiked with Cr(VI). Fe0 nanoparticles were synthesized by the reduction of ferric chloride with sodium borohydride and were characterized by UV–Vis
(Ultra violet–Visible) and FTIR (Fourier transform infrared) spectroscopy. The UV–Vis spectrum of Fe0 nanoparticles suspended in 0.8% Carboxymethyl cellulose showed its absorption maxima at 235 nm. The presence of one band
at 3,421 cm−1 ascribed to OH stretching vibration and the second at 1,641 cm−1 to OH bending vibration of surface-adsorbed water indicates the formation of ferrioxyhydroxide (FeOOH) layer on Fe0 nanoparticles. The mean crystalline dimension of Fe0 nanoparticles calculated by XRD (X-ray diffraction) using Scherer equation was 15.9 nm. Average size of Fe0 nanoparticles calculated from TEM (Transmission electron microscopy) images was found around 26 nm. Dynamic Light Scattering
(DLS) also showed approximately the same size. Batch experiments were performed using various concentration of Fe0 nanoparticles for reduction of soil spiked with 100 mg kg−1 Cr(VI). The reduction potential of Fe0 nanoparticles at a concentration of 0.27 g L−1 was found to be 100% in 3 h. Reaction kinetics revealed a pseudo-first order kinetics. Factors like pH, contact time, stabilizer,
and humic acid facilitates the reduction of Cr(VI). 相似文献
38.
Manohar Mahato Gaurav Rana Pradeep Kumar Ashwani Kumar Sharma 《Journal of polymer science. Part A, Polymer chemistry》2012,50(12):2344-2355
Highly toxic polyallylamine (PA) was reacted with a varying amount of a novel linker, 6‐(N,N,N′,N′‐tetramethylguanidinium chloride) hexanoic acid (Tmg‐HA), to prepare a series of tetramethylguanidinium‐PA (Tmg‐PA) polymers, which were used as vectors for gene transfection. The extent of attachment of the linker, Tmg‐HA, to the PA backbone was determined by 2,4,6‐trinitrobenzene sulfonic acid assay. The modified polymers (Tmg‐PAs), when complexed with pDNA, exhibited good condensation ability. The nanoparticles, so formed, were characterized by their size and zeta potential and were subsequently evaluated for their toxicity and transfection ability on various mammalian cells, viz., HeLa, CHO, and HEK 293 cells. Mobility shift assay revealed that on increasing the percent substitution of Tmg‐HA onto PA (from Tmg‐PA1 to Tmg‐PA6), relatively higher amounts of modified polymers were required to retard the mobility of a fixed amount of DNA. Besides, Tmg‐PA polymers provided sufficient protection (ca. 84–88%) to bound DNA against nucleases and one of the formulations, Tmg‐PA2 (ca. 15% substitution) displayed the highest transfection efficiency outcompeting the commercial transfection reagent, Lipofectamine? with minimal cytotoxicity. More impressively, the transfection efficiency increased despite recording a decrease in the buffering capacity of the grafted polymers suggesting that buffering capacity is not the sole parameter in determining the gene delivery efficiency of a vector system. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
39.
S. Leray G. Nebbia C. Gregoire G. La Rana P. Lhenoret C. Mazur C. Ngô M. Ribrag E. Tomasi S. Chiodelli J.L. Charvet C. Lebrun 《Nuclear Physics A》1984,425(2):345-353
We have measured the angular correlation between two fragments emitted in the reactions Ar + Au and Ar + U at 44 MeV/u at GANIL. The aim was to investigate the amount of initial linear momentum transferred from the projectile to a fissioning nucleus. It turned out that this amount is much smaller than can be extrapolated from previous experiments. Furthermore, the probability of forming a fissioning nucleus is very small. 相似文献
40.
A canonical planar beta-hairpin peptide, stereochemically reengineered into a semicircular bracelet type motif by L-to-D stereochemical inversion in two pairs of its cross-strand neighbor residues, displays protein like ordering including two-state behavior in H2O, which is unusual for a small peptide of this size. 相似文献