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1.
D. Amutha Rani Y. Yamamoto S. Mohri M. Sivakumar Y. Tsujita H. Yoshimizu 《Journal of Polymer Science.Polymer Physics》2003,41(3):269-273
In this study, a novel stepwise extraction method has been examined. The guest molecules housed between the helices of the clathrate δ form of syndiotactic polystyrene can be removed completely with this method. A systematic study of the preparation of a solvent‐free mesophase (emptied clathrate) membrane, its helical and residual solvent contents, and its structural transformations has been performed. In this first attempt, an enhancement in the TTGG helical content has been observed in the extracted membrane, and a conceptual mechanism is proposed. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 269–273, 2003 相似文献
2.
S. Mohri D. Amutha Rani Y. Yamamoto Y. Tsujita H. Yoshimizu 《Journal of Polymer Science.Polymer Physics》2004,42(2):238-245
Syndiotactic polystyrene (sPS) has various crystalline forms such as α, β, γ, and δ forms, and a mesophase depending on the preparation method. In this study, we focused on the mesophase with the molecular cavity of sPS, which is obtained by step‐wise extraction of the guest molecules from the sPS δ form. To prepare the mesophase containing different shapes and sizes of the cavity, two kinds of the sPS δ form membrane cast from either toluene or chloroform solution were first prepared and then the guest molecules were removed by a step‐wise extraction method using acetone and methanol. We could succeed in the preparation of two kinds of mesophase with different shapes and sizes of the molecular cavity. Either toluene or chloroform vapor sorption to the sPS mesophase membranes was examined at 25 °C. Sorption analysis indicates that the mesophase with large molecular cavities can mainly sorb large molecules; on the other hand, the mesophase with small cavities can sorb only the small molecules, and is unable to sorb a large amount of large molecule because the cavity was too small to sorb the large molecules. Therefore, the sPS mesophase membrane has sorption selectivity based on the size of the molecular cavity. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 238–245, 2004 相似文献
3.
Sunanda Banerjee Rohini M Godbole Sreerup Raychaudhuri Ben Allanach Sunanda Banerjee Satyaki Bhattacharyya Debajyoti Choudhury Siba Prasad Das Anindya Datta Rohini M Godbole Monoranjan Guchait Sabine Kraml Gobinda Majumdar David Miller Margarete Mühlleitner Nobuchika Okada Maxim Perelstein Santosh K Rai Sreerup Raychaudhuri Saurabh D Rindani DP Roy K Sridhar Rishikesh Vaidya D Zeppenfeld 《Pramana》2006,67(4):617-637
This is summary of the activities of the working group on collider physics in the IXth Workshop on High Energy Physics Phenomenology
(WHEPP-9) held at the Institute of Physics, Bhubaneswar, India in January 2006. Some of the work subsequently done on these
problems by the subgroups formed during the workshop is included in this report. 相似文献
4.
Chattopadhyay S Srivastava AK Bisaria VS 《Applied biochemistry and biotechnology》2002,102(1-6):381-393
The root explants of the germinated seedlings of Podophyllum hexandrum were grown in MS medium supplemented with indole acetic acid (IAA) (2 mg/L) and activated charcoal (0.5%), and healthy callus
culture was obtained after incubation for 3 wk at 20°C. The cultivation of plant cells in shake flask was associated with
problems such as clumping of cells and browning of media, which were solved by the addition of pectinase and polyvinylpyrrolidone.
The effect of major media components and carbon source was studied on the growth and podophyllotoxin production in suspension
culture. It was found that glucose was a better carbon source than sucrose and that NH4
+:NO3
− ratio (total nitrogen concentration of 60 mM) and PO4
3− did not have much effect on the growth and product formation. The relative effect of culture parameters (inoculum level,
pH, IAA, glucose, NH4
+:NO3
− ratio, and PO4
3−) on the overall growth and product response of the plant cell suspension culture was further investigated by Plackett-Burman
design. This indicated that inoculum level, glucose, IAA, and pH had significant effects on growth and production of podophyllotoxin.
To identify the exact optimum concentrations of these parameters on culture growth and podophyllotoxin production, central
composite design experiments were formulated. The overall response equations with respect to growth and podophyllotoxin production
as a function of these culture parameters were developed and used to determine the optimum concentrations of these parameters,
which were pH 6.0, 1.25 mg/L of IAA, 72 g/L of glucose, and inoculum level of 8 g/L. 相似文献
5.
Prakash O Kaur H Batra H Rani N Singh SP Moriarty RM 《The Journal of organic chemistry》2001,66(6):2019-2023
The combination reagent (dichloroiodo)benzene and lead(II) thiocyanate in dichloromethane effects oxidation of various enol silyl ethers, ketene silyl acetals, and beta-dicarbonyl compounds, thereby providing an efficient and convenient method for alpha-thiocyanation of carbonyl and beta-dicarbonyl compounds. 相似文献
6.
Perchloric acid supported on silica gel acts as an excellent reagent system in converting glucals into 2,3-unsaturated-O-glucosides in good to excellent yields in short reaction time with good alpha selectivity. Primary, secondary, and allylic alcohols, phenols, and thiols react with 3,4,6-tri-O-acetyl glucal with equal ease. In addition to this, a chiral furan diol is obtained from unprotected D-glucal or D-galactal in good yields. 相似文献
7.
Saurabh D Rindani 《Pramana》1995,45(Z1):263-276
The prospects of experimental detection ofCP violation ate
+
e
− and
colliders are reviewed. After a general discussion on the quantities which can measureCP violation and on the implications of theCPT theorem, various possibilities of measuringCP violation arising outside the standard model are taken up.CP violation in leptonic processes, especially polarization effects ine
+
e
−→l
+
l
− are discussed next.CP violation in
andW
+
W
− production and decay is also described. 相似文献
8.
On the mechanism of nanopore filling of SAPO-5 molecular sieve by nitrogen molecules 总被引:1,自引:0,他引:1
Boddenberg B Radha Rani V Grosse R 《Langmuir : the ACS journal of surfaces and colloids》2004,20(25):10962-10969
SAPO-5 molecular sieve was synthesized according to patent literature and characterized with X-ray diffraction, electron microscopy (SEM, TEM), and solid state magic angle spinning NMR spectroscopy. The material of particles in the micrometer region was found to consist of ca. 20 nm microcrystallites packed in mostly parallel orientation to ca. 200 nm sized agglomerates. The nitrogen adsorption isotherm was measured at 77.6 K over ca. 7 decades of pressure up to pore saturation. The course of the isotherm is interpreted to consist of filling of the nanopores (diameter, 0.73 nm) up to 2N(2)/unit cell, subsequent multilayer adsorption on the outer surface of the agglomerates, and, finally, pore condensation in the interparticle adsorption space. The nanopore adsorption can be quantitatively reproduced with the statistical mechanical model of a quasi one-dimensional lattice gas taking intermolecular interactions into account. The evaluated energy parameters are of physically reasonable magnitude and agree with literature data. The multilayer part of the adsorption isotherm can be well represented by the Brunauer-Emmett-Teller model yielding a specific outer space area (63 m(2) g(-)(1)) which is consistent with estimated geometrical and pore size analysis data. 相似文献
9.
A silver selective electrode based on TEPQA‐MCM‐41 material was developed and used for the selective determination of Ag+ ion in various samples. The effect of various plasticizers i. e. dimethyl phthalate (DMP), Tris(ethylhexyl)phosphate (TEP), bis‐(2‐ethylhexyl)sebacate (BEHS), bis‐(2‐ethylhexyl)adipate (BEHA) was investigated. The electrode of the composition of 2 : 1 : 77 : 12 : 8 (w/w, %) of TEPQA‐MCM‐41 : NaTPB : Graphite powder : paraffin oil : DMP respectively, works satisfactorily in a wide concentration range of 1.3×10?9 M–1.0×10?1 M for Ag+ ion with a lower detection limit (LOD) of 1.0×10?9 M and has Nernstian slope of 63.4 1 mV/decay. The electrode can be used in a pH range of 2.3 to 6.7 for a period of 3 months without any divergence in potential response. The selectivity coefficient calculated by fixed interference method indicates the high selectivity of the electrode towards Ag+ ion over other tested cations. 相似文献
10.
Moriarty RM Rani N Enache LA Rao MS Batra H Guo L Penmasta RA Staszewski JP Tuladhar SM Prakash O Crich D Hirtopeanu A Gilardi R 《The Journal of organic chemistry》2004,69(6):1890-1902
A general and novel solution to the synthesis of biologically important stable analogues of prostacyclin PGI(2), namely benzindene prostacyclins, has been achieved via the stereoselective intramolecular Pauson-Khand cyclization (PKC). This work illustrates for the first time the synthetic utility and reliability of the asymmetric PKC route for synthesis and subsequent manufacture of a complex drug substance on a multikilogram scale. The synthetic route surmounts issues of individual step stereoselectivity and scalability. The key step in the synthesis involves efficient stereoselection effected in the PKC of a benzoenyne under the agency of the benzylic OTBDMS group, which serves as a temporary stereodirecting group that is conveniently removed via benzylic hydrogenolysis concomitantly with the catalytic hydrogenation of the enone PKC product. Thus the benzylic chiral center dictates the subsequent stereochemistry of the stereogenic centers at three carbon atoms (C(3a), C(9a), and C(1)). 相似文献