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81.
Kento Okoshi Anubhav Saxena Masanobu Naito Goro Suzaki Masatoshi Tokita Junji Watanabe Michiya Fujiki 《Liquid crystals》2004,31(2):279-283
A smectic A-cholesteric phase transition for a rigid-rod helical polymer, poly[n-decyl-(S)-2-methylbutylsilane] (PD2MBS), with a narrow molecular weight distribution, has been observed for the first time. Polarizing optical microscopy showed that the fan-shaped texture of the smectic A phase turned into the characteristic planar texture of the cholesteric phase upon heating. The positive CD band, which corresponds to the reflection band of the cholesteric phase, gradually decreased in intensity within a range 30°C below the transition temperature on cooling, while the peak maximum shifted towards shorter wavelengths. It was concluded that the system has a very wide temperature region over which the cholesteric-smectic A phase transition occurs and in which the cholesteric pitch varies with temperature. 相似文献
82.
THEESTIMATIONOFPRIORFROMFISHERINFORMATION¥LIYUANZHANG;K.M.LALSAXENAANDQIANGWENJIUAbstract:InBayesiananalysis,themaximumentrop... 相似文献
83.
Transition Metal Chemistry - Cyclopentadienylzirconium(IV) complexes of N-phthaloyl amino acids of general formulae Cp2Zr(L)nCl2?n (n = 1 or 2) and CpZrCl(L)2 (LH = N-phthaloyl derivatives of... 相似文献
84.
85.
Salahudeen Nurudeen Ahmed Abdulkarim S. Al-Muhtaseb Ala’a H. Dauda Mohammed Jibril Baba Y. Viswanadham Nagabhatla Saxena Sandeep K. 《Research on Chemical Intermediates》2017,43(1):467-479
Research on Chemical Intermediates - This study presents the synthesis of rare earth-doped Y (RE Y) zeolite, its application in formulation of a fluid catalytic cracking (FCC) catalyst and the... 相似文献
86.
In an attempt to convert the carcinogenic benzene which is almost restricted for its use in gasoline, alkylation reaction with olefin 1-hexene has been conducted on various zeolites. Four zeolites having different pore topology and pore size have been applied as solid acid catalysts for effective production of alkylate in a liquid phase, solvent-less low temperature reaction. The textural properties of all the four zeolites (ZSM-5, MOR, BEA, HY) have been characterized for crystal morphology by TEM, crystal structure by XRD and FTIR, BET for surface area, N2 sorption for porosity and TPD for acidity. Among the zeolite, BEA possessed high surface area (600.61 m2/g) and enhanced meso pores volume (0.3956 cm3/g) as compared to other zeolite samples. The performance of BEA was also observed to be superior in the liquid phase alkylation of benzene with 1-hexene in a batch reactor under autogenous pressure without using any solvent. At the optimum reaction conditions, the benzene conversion was 86.6 wt% and 3-Phenylhexane, 2-Phenylhexane yield were about 47.9 wt% and 38.7 wt% respectively on this catalyst. The BEA also exhibited longer time-on-stream and reusability performance, thus offers an attractive route for converting benzene into valuable (3-Phenylhexane, 2-Phenylhexane) alkylate product useful for the manufacturing of fine chemicals, dyestuff, detergents and scents. 相似文献
87.
V. Prakash Y. Narayana M. K. Saxena S. B. Deb B. K. Nagar K. L. Ramakumar 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(1):103-107
The concentration of five trace elements Cr, As, Pb, Rb and Sr in seven medicinal plants Garcinia indica, Ficus benghalensis, Flacartia Montana, Nyctanthes arbor-tristis, Morinda citrifolia, Ficus recemosa, Barringtonia acutangula and associated soils were analyzed using ICP-MS. In plant the elemental concentrations of Cr, Pb, Rb and Sr vary widely and
in soil the elemental concentrations of Cr, As and Sr showed wide variation. Selective enrichment of elements Rb and Sr was
observed in some plants. The soil to plant transfer ratio was significant for Sr. The results of these systematic investigations
are presented and discussed in this paper. 相似文献
88.
Analysis of cellulose biosynthesis using molecular approaches has been successful in identifying genes in many cellulose-producing
organisms, yet the mechanism of cellulose biosynthesis still remains to be understood. We are interested in developing the
moss Physcomitrella patens as a useful system for the study of cellulose biosynthesis. This moss affords a number of advantages including a haploid
dominated gametophyte and a very high efficiency of homologous recombination in its nuclear DNA for constructing gene knockouts.
In addition, P. patens has only a primary cell wall unlike Arabidopsis thaliana, which has both a primary and a secondary cell wall. We identified two full-length cellulose synthase (CesA) genes of P. patens, PpCesA6 and PpCesA7 from an EST database and have analyzed the genomic sequences. PpCesA6 and PpCesA7 show high similarity to each other, both at the cDNA and genomic DNA levels. Single and double knockouts of PpCesA6 and PpCesA7 were generated and screened for phenotypic changes. While the PpCesA6 and PpCesA7 single knockouts did not show any obvious phenotypic differences from the wild-type, the double knockout had significantly
reduced stem length. These results suggest that PpCesA6 and PpCesA7 probably have a very similar role in cellulose biosynthesis and their functions may be redundant. Additionally, their roles
may overlap with the other P. patens CesAs as observed for CesAs involved in primary cell wall biosynthesis in A. thaliana. 相似文献
89.
Measurements have been taken on a glass trennschaukel of eight tubes for the Ar-He system as a function of composition and with its hot and cold bulbs at 100°c and 0°c. For each mixture, several speeds for the mechanical push-pull motion of the gas which cover a wide enough range were tried. The results have been interpreted to determine the thermal diffusion factor α T, in conventional fashion as well as on the basis of a theory characterizing the low speed operation, developed here. Four such different possibilities of α t evaluation are discussed and values compared with the traditional ones obtained from the convection-free two-bulb apparatus. Lastly we discuss also in brief the prospect of estimating the diffusion coefficient as an important byproduct from measurements on trennschaukel runs. 相似文献
90.