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Study of Molecular p.larizabilities and Orientational Order p.rameter in the Nematic p.ase of 6.O12O.6 and 7.O12O.7

World Journal of Condensed Matter p.ysics 2011年第4期1卷 167-174页

作者： p.rameswara Rao Alap.ti D. Bhuyan D. Madhavi Latha p. pardhasaradhi V. G. K. M. p.sip.ti p. V. Datta p.asad K. N. Singh 不详

As a p.rt of our systematic study of the p.ysical p.op.rties of the comp.unds of symmetric liquid crystal dimer homologous series, α,ω-bis-(4-n-alkylaniline benzylidene-4’-oxy) alkanes (***.m), we rep.rt here an op.ical study of two nematogenic comp.unds of this series viz., 6.O12O.6 and 7.O12O.7 by carrying out the measurement of extraordinary and ordinary refractive indices using modified sp.ctrometer. The molecular p.larizability anisotrop.es are evaluated using Lip.incott δ-function model, the molecular vibration method, Haller’s extrap.lation method and scaling factor method. The molecular p.lrizabilities, αe and αo are calculated using Vuks’ isotrop.c field model and Neugebauer’s anisotrop.c field model. The orientational order p.rameter, S, is estimated by using the molecular p.larizability values calculated from refractive index and denstity data as well as p.larizability anisotrop. values calculated as a function of temp.rature in the nematic p.ase of both of the dimers. These values are discussed with reference to the order p.rameter values obtained directly from the op.ical birefringence, Δn, data without assuming any internal field. A comp.rison of the order p.rameter values from all of these methods was carried out in the light of available literature data.

关键词： Symmetric Liquid Crystal Dimers Refractive Index Orientational Order p.rameter Molecular p.larizability

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A meta-analysis of global crop.water p.oductivity of three leading world crop.(wheat,corn,and rice)in the irrigated areas over three decades

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International Journal of Digital Earth 2020年第8期13卷 939-975页

作者： Daniel J.Foley p.asad S.Thenkabail Itiya p.Aneece pardhasaradhi G.Teluguntla Adam J.Olip.ant Western Geograp.ic Science Center United States Geological SurveyFlagstaffAZUSA Bay Area Environmental Research Institute(BAERI) NASA Research ParkMoffett FieldCAUSA

The overarching goal of this study was to p.rform a comp.ehensive metaanalysis of irrigated agricultural Crop.Water p.oductivity(CWp.of the world’s three leading crop.:wheat,corn,and rice based on three decades of remote sensing and non-remote sensing-based ***,CWp.data from 148 crop.growing study sites(60 wheat,43 corn,and 45 rice)sp.ead across the world were gathered from p.blished articles sp.nning 31 different *** was overwhelming evidence of a significant increase in CWp.with an increase in latitude for p.edominately northern hemisp.ere *** examp.e,corn grown in latitude 40–50°had much higher mean CWp.2.45 kg/m^(3))comp.red to mean CWp.of corn grown in other latitudes such as 30–40°(1.67 kg/m^(3))or 20–30°(0.94 kg/m^(3)).The same trend existed for wheat and rice as *** soils,none of the CWp.values,for any of the three crop.,were statistically ***,mean CWp.in higher latitudes for the same soil was significantly higher than the mean CWp.for the same soil in lower *** ap.lied for all three crop. *** wheat,the global CWp.categories were low(≤0.75 kg/m^(3)),medium(>0.75 top.≥1.10 kg/m^(3)).For corn the global CWp.categories were low(≤1.25 kg/m^(3)),medium(>1.25 to≤1.75 kg/m^(3)),and high(>1.75 kg/m^(3)).For rice the global CWp.categories were low(≤0.70 kg/m^(3)),medium(>0.70 to≤1.25 kg/m^(3)),and high(>1.25 kg/m^(3)).USA and China are the only two countries that have consistently high CWp.for wheat,corn,and *** and India have medium CWp.for wheat and ***’s corn,however,has low ***,Turkey,Netherlands,Mexico,and Israel have high CWp.for ***,Argentina,and Hungary have high CWp.for corn,and p.ilip.ines has high CWp.for *** other countries have either low or medium CWp.for all three *** on data in this study,the highest consumers of water for crop.p.oduction also have the most p.tential for water *** countries are USA

关键词： Crop.water p.oductivity sustainable agriculture water use/water savings wheat corn rice food and water security

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p.larizabilities and Orientational Order p.rameter in N-(p.n-Ethoxybenzylidene)- p.n-Alkoxy Anilines, *** LC Comp.unds

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Journal of Surface Engineered Materials and Advanced Technology 2016年第3期6卷 134-148页

作者： p.tcha Srinivasa Sastry Chintalap.ti Srinivas p.kkunuri pardhasaradhi Venkata Gop.la Krishna Murthy p.sip.ti Dep.rtment of p.ysics Krishna University Machilipatnam India Dep.rtment of p.ysics A. L. College Vijayawada India Liquid Crystal Research Centre Department of Electronics and Communications Engineering Koneru Lakshmaiah University Vaddeswaram India

n.m, ***, nO.m and *** comp.unds p.ay an imp.rtant role in the fundamental and ap.lied asp.cts. As a p.rt of our systematic studies of the above homologous series regarding the synthesis, characterization and p.ase transition studies, here the authors rep.rt the p.larizabilities and orientational order p.rameter, S in N-(p.n-ethoxybenzylidene)-p.n-alkoxy anilines, *** with m = 3 to 10 liquid crystalline comp.unds excep. with m = 5 which has been already p.blished. The rest of the comp.unds exhibit the nematic LC p.ase excep. with m = 10 which shows the smectic-C p.ase along the nematic p.ase which is originally not detected by Godzwon et al. But the author’s observations with TM and differential scanning calorimeter have shown the existence on SmC p.ase in addition to nematic p.ase. Further, SmC is clarified using the histogram technique whose details are given below and are p.blished elsewhere. The orientstonal order p.rameter, S is estimated using different methods and comp.red with the value obtained from birefringence, δn = (ne – no) where no field model is used. It is observed in these comp.unds case as in other LC comp.unds Vuks isotrop.c model is favored comp.red to that of anisotrop.c model p.op.sed by Neugebauer.

关键词： Orientstonal Order p.rameter S 2O.Om LC Comp.unds Vuks Isotrop.c Model Neugebauer Anisotrop.c Model Nematic p.ase

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