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151.
Multilayer assemblies of uniform ultrathin film electrodes with good electrical conductivity and very large surface areas were prepared for use as electrochemical capacitors. A layer-by-layer self-assembly approach was employed in an effort to improve the processability of highly conducting polyaniline (PANi) and chemically modified graphene. The electrochemical properties of the multilayer film (MF-) electrodes, including the sheet resistance, volumetric capacitance, and charge/discharge ratio, were determined by the morphological modification and the method used to reduce the graphene oxide (GO) to reduced graphene oxide (RGO) in the multilayer films. The PANi and GO concentrations could be modulated to control the morphology of the GO monolayer film in the multilayer assemblies. Optical ellipsometry was used to determine the thickness of the GO film in a single layer (1.32 nm), which agreed well with the literature value (~1.3 nm). Hydroiodic acid (HI), hydrazine, or pyrolysis were tested for the reduction of GO to RGO. HI was found to be the most efficient technique for reducing the GO to RGO in the multilayer assemblies while minimizing damage to the virgin state of the acid-doped PANi. Ultimately, the MF-electrode, which could be optimized by fine-tuning the nanostructure and selecting a suitable reduction method, exhibited an excellent volumetric capacitance, good cycling stability, and a rapid charge/discharge rate, which are required for supercapacitors. A MF-electrode composed of 15 PANi/RGO bilayers yielded a volumetric capacitance of 584 F/cm(3) at a current density of 3.0 A/cm(3). Although this value decreased exponentially as the current density increased, approaching a value of 170 F/cm(3) at 100 A/cm(3), this volumetric capacitance is one of the best yet reported for the other carbon-based materials. The intriguing features of the MF-electrodes composed of PANi/RGO multilayer films offer a new microdimensional design for high energy storage devices for use in small portable electronic devices. 相似文献
152.
Delazar A Modarresi M Shoeb M Nahar L Reid RG Kumarasamy Y Majinda RR Sarker SD 《Natural product research》2006,20(2):167-172
The reversed-phase preparative HPLC analysis of the methanol extract of the rhizomes of Eremostachys glabra (Lamiaceae) led to the isolation of two furanolabdane diterpene glycosides, phlomisoside II, and beta-D-glucopyranosyl-(1-->2)-beta-D-glucopyranosyl ester of phlomisoic acid (named eremostachiin), the latter being a novel natural product. The structure of the new compound has been elucidated unambiguously by HRMS and a series of 1D- and 2D-NMR spectroscopic techniques. The free radical scavenging activity of these compounds was assessed using the DPPH assay. 相似文献
153.
Sahena Ferdosh Md. Zaidul Islam Sarker Nik Norulaini Nik Abd Rahman Jinap Selamat Md. Rezaul Karim Tariq Abdul Razak Mohd Omar Abd Kadir 《中国化学会会志》2012,59(11):1421-1429
Fish viscera, a waste of fish processing industry, can be exploited as a source of PUFA‐rich fish oil for use in food or pharmaceutical industry and at the same time the environment can be protected from pollution by fish wastes. Fish oil was recovered from viscera of Indian Mackerel (Rastrelliger kanagurta), by different supercritical fluid extraction (SFE) e.g. continuous, co‐solvent, soaking, and pressure swing techniques and the yields were compared with that of the solvent extraction method. The SFE parameters such as pressure, temperature, and CO2 flow rate were optimised by employing Response Surface Methodology (RSM) with a view to maximize the oil yield and minimize CO2 consumption. The central composite rotatable design (CCRD) consisting of three variables provided 20 experimental settings. Multiple regressions determined the coefficients of the second‐order polynomial equation. The optimum parameters for all 4 techniques applied were found to be 35 MPa, 60 °C, and 2 mL min?1 with an Oil recovery ranging from 93 to 99%. The study demonstrated a lower CO2 consumption by the soaking and pressure swing techniques at the optimized conditions. Thus, the soaking and pressure swing techniques were most effective for extracting oil from fish viscera. 相似文献
154.
Nik Norulaini Nik Abd. Rahman Salman Zhari Md. Zaidul Islam Sarker Sahena Ferdosh Mohd Azizi Che Yunus Mohd Omar Abd Kadir 《中国化学会会志》2012,59(4):507-514
A rapid identification, classification and discrimination tool, using Fourier Transform Infrared (FTIR) spectroscopy combined with Principal Component Analysis (PCA), was developed and applied to determine the profile of the Supercritical Fluid Extraction (SFE) of Parkia speciosa seeds under various temperature and pressure conditions (313, 323, 333, 343, 353 and 363 K and 20.68, 27.58, 34.47, 41.37, 48.26, and 55.16 MPa). The separation and identification of the compounds was carried out by Gas Chromatography coupled with Time of Flight Mass Spectrometry (GC/TOF‐MS). This technique has made it possible to detect the variability obtained under different SFE conditions and the separation of different chemical compounds in P. speciosa seeds. The FTIR‐PCA results were verified by GC/TOF‐MS, and the FTIR‐PCA method successfully identified the unsaturated carboxylic acids with the highest percentage area under the different conditions. 相似文献
155.
Just-in-time (JIT) procurement is one of the important elements of lean production system. Successful implementation of JIT needs vendor-manufacturer cooperation on small lot size delivery and inbound logistics cost reduction. Unlike the most recent literature focusing on single-vendor and single-buyer integrated inventory systems, this paper studies a multi-vendor integrated procurement-production inventory system that incorporates delivery and shared transportation costs. A multi-vendor optimal model is developed here for deciding the batch size of vendor's production, and delivery frequencies of different vendors to the manufacturer. Solution procedures for two special cases—uncapacitated and capacitated models are developed; especially, a new approximate method for capacitated model is devised. Numerical examples demonstrate the solution mechanism for the model. The results highlight cooperation between vendors and manufacturers on JIT procurement practices. 相似文献
156.
The paper deals with the imprtance of the Kullback descrimination information in the statistical characterization of negentropy of non-equilibrium state and the irreversibility of a classical dynamical system. The theory based on the Kullback discrimination information as theH-function gives new insight into the interrelation between the concepts of coarse-graining and the principle of sufficiency leading to important statistical characterization of thermal equilibrium of a closed system. 相似文献
157.
The isolation, comprehensive structure elucidation, and assessment of the free radical scavenging activity of caffeic acid decyl ester (1) from the seeds of Phleum pratense have been described. The RC50 value of this compound in the DPPH assay was found to be 3.60 × 10−3 mg/mL, whereas that of positive control, trolox, was 3.07 × 10−3 mg/mL.__________Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 237–239, May–June, 2005. 相似文献
158.
Sanjay Senapoti Kamal Krishna Sarker Tapan Kumar Mondal Chittaranjan Sinha 《Transition Metal Chemistry》2006,31(3):293-298
2-(Methyl)-4-(arylazo)imidazole (RLH) (1, 2) are new series of azoimidazoles. Upon treatment of alkylhalide in dry THF in presence of NaH has synthesised 1-alkyl-2-(methyl)-4-(arylazo)imidazole
(RLR′) (3, 4). They belong to the azoimine family of N,N′-chelating ligand. They stabilize the Cu(I) oxidation state and we have synthesized [Cu(RLR′)2](ClO4) (5, 6). These complexes show a moderately intense visible band (500–600 nm) which has been assigned to 3d(Cu) → π*(ligand) transition. Ag(I) complexes of RLR′ (7, 8) are also very stable under ambient conditions and show weak transitions in the visible region. The Cu(I)-complexes show high
potential Cu(II)/Cu(I) redox couple > 0.4 V vs Ag, AgCl/Cl− reference electrode. All these complexes have been structurally characterized by 1H NMR spectroscopic data. 相似文献
159.
Prashanta Sarkhel Sekhar Ch. Sarker Akhilesh K. Gupta Raj K. Poddar 《Transition Metal Chemistry》1996,21(3):250-253
Summary The syntheses of new dinuclear and mononuclear complexes of RuII trifluoroacetate containing monodentate co-ligands, namely [Ru2(-O2CCF3)4L2] (L = py, 2-Mepy or 3-Mepy); trans-[Ru(O2CCF3)2L4] (L = 2-Mepy or 3-Mepy); [Ru(O2CCF3)(PPh3)4](O2CCF3) and [Ru(O2CCF3)2(CO)(MPh3)3] (M = P or As), are described. The complexes have been characterized by physical and electrochemical studies. 相似文献
160.