Solubility of CO2 in room temperature ionic liquid [hmim][Tf2N

Solubility measurements of carbon dioxide in 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide have been performed with a gravimetric microbalance at temperatures of about 282, 297, 323, and 348 K and pressures up to about 2 MPa. Two different sources for the ionic liquid are examined in this work: an ultrapure sample from NIST (the IUPAC task force sample) and a commercially available sample. Both samples show nearly identical solubility behaviors, being undistinguishable within experimental uncertainties. Solubility (pressure-temperature-composition) data have been well correlated with an equation-of-state (EOS) model used in our previous works. The EOS model calculations are compared with experimental solubility data for the same system in the literature. The present EOS has predicted partial immiscibility at the CO2-rich side solutions. To prove this prediction, vapor-liquid-liquid equilibrium experiments have been made, and our predictions have been confirmed.     

Thermal effect on C-H stretching vibrations of the imidazolium ring in ionic liquids

We have studied temperature dependent IR spectra of the C-H stretching modes of the imidazolium ring in [bmim][PF(6)], [bmim][Tf(2)N], [emim][Tf(2)N], [hmim][Tf(2)N], and [bmim][BF(4)]. Temperatures in this study are from 278 to 348 K at an interval of 10 K. Spectra of the C-H stretching modes have been deconvoluted using our previous computer program of the Voigt-lineshape function. Frequency shifts, Lorentzian spectral widths, and band absorbance were examined as a function of temperature. In order to interpret the observed behaviors, we have developed a simple mechanical model as well as a chemical equilibrium model. The model analyses suggest that enthalpy changes for the cluster and/or ion-pair breaking reactions in the liquid state are several kJ mol(-1) endothermic, and the degree of dissociations of ion pairs or hydrogen bonded clusters is in the range from 0.3 to 0.9 with different magnitudes for the five ionic liquids.     

Doubly stochastic measures with prescribed support

Summary Denote the set of doubly stochastic measures on the unit square X ×X that are supported on the graphs of measurable maps L,HXX by (L, H). Conditions are given that imply that (L, H) is a singleton. Since (L, H) is in any event a (possibly empty) extremal subset of the set of all doubly stochastic measures on X×X, our results are intimately related to the problem of describing the supports of the extreme points of .     

Analysis of transmembrane dynamics of cholera toxin using photoreactive probes.

Using sodium dodecyl sulfate--polyacrylamide gel electrophoresis and autoradiography, we have shown that 125I-labeled cholera toxin binds to Newcastle disease virus. Pretreatment of Newcastle disease virus with "cold" cholera toxin (at 37 degrees C for 30 minutes) inhibits the binding of 125I-labeled toxin in a subsequent incubation (at 37 degrees C for 30 minutes). These results suggest that cholera toxin binds to Newcastle disease virus in a specific manner. The precise receptor for toxin is unknown in Newcastle disease virus but it is presumed to be the ganglioside GM1. We have previously shown that the photoreactive probe 12-(4-azido-2-nitrophenoxy)stearoylglucosamine[1-14C] labels the membrane proteins of Newcastle disease virus. Since the reactive group of the probe, ie, N3, resides within the membrane bilayer, studies were initiated to determined which, if any, of the subunits of cholera toxin cross the membrane of Newcastle disease virus and become radioactively labeled upon photoactivation of the probe at 360 nm. After a 15-minute incubation of cholera toxin with Newcastle disease virus containing the photoreactive probe, irradiation effected the 14C-labeling of the active A1 subunit of cholera toxin. Irradiation of cholera toxin in solution with an equivalent amount of probe but without virus resulted in no labeling of toxin subunits.     

Quasielastic reactions around the coulomb barrier in 16O+118Sn

Measurement of elastic and quasielastic reaction cross sections were done in ¹⁶O + ¹¹⁸Sn system at two different energies above the barrier. Attempts are being made to understand the results in the framework of coupled reaction channel model.     

Doubly stochastic matrices over arbitrary vector spaces and the Birkhoff theorem

Doubly stochastic matrices are defined which have entries from an arbitrary vector space V. The extreme points of this convex set of matrices are studied, and convex subsets of V are identified for which these extreme matrices are of a permutation matrix type, i.e. for which a Birkhoff theorem holds.     

ICP-AES分析光谱条件对中药蒲公英无机元素吸收的影响

在全密闭植物工厂中水培种植中药蒲公英,以发射不同波段光谱的荧光灯及LED灯作为药材生长光源,并结合ICP–AES技术分析了不同光谱条件对蒲公英无机元素吸收和积累的影响。结果表明:(1)相近的光合有效辐射(PAR)条件下,单一红光R及混合光FLRB有利于水培蒲公英可食生物量的积累,单一蓝光B处理下可食生物量最低;(2)荧光灯FL条件下蒲公英地上部分常量无机元素含量比值为K∶Ca∶P∶Mg∶Na=79.74∶32.39∶24.32∶10.55∶1.00,微量无机元素含量比值为Fe∶Mn∶B∶Zn∶Cu=9.28∶9.71∶3.82∶2.08∶1.00;(3)峰值为660nm的红光有利于蒲公英对Ca,Fe,Mn,Zn元素的吸收,Cu元素含量受光谱条件的影响不明显;(4)蒲公英地上部分对Ca,Na,Mn,Zn四种元素的积累量均在纯红光R下最高,而对其余六种元素的积累量以混合光FLRB条件下最高。