IR Study of Monomer–Dimer Self-association of 2,2-Dimethyl-3-ethyl-3-pentanol in n-Octane: Determination of the Molar Absorptivities of Monomer and Dimer Bands, and Dimerization Constants Using Novel Equations

The monomer–dimer self-association equilibrium of 2,2-dimethyl-3-ethyl-3-pentanol in n-octane has been studied by IR spectroscopy at four temperatures (288, 298, 308, and 318 K). The solute was chosen to restrict the self-association between solute molecules to dimerization only, owing to steric hindrance of the bulky chains in the vicinity of the OH group. Two linear equations have been derived for the treatment of the experimental data. One of these equations was used to treat the data of the concentration dependent integrated absorbance of the monomer bands for each temperature to obtain the monomer molar absorptivity, ε _m, and dimerization constant, K. The other equation was used to treat the data of concentration-dependent dimer bands to obtain the dimer molar absorptivity, ε _d, and K. Thus, the dimerization constant was determined by two methods. Since the same thermodynamic quantity K is obtained from either the monomer bands or the dimer bands, the difference between them at a given temperature can serve as an assessment of the quality of the experiment. The standard enthalpy and entropy of dimerization were also obtained from a van’t Hoff plot.     

Molecular dynamic-secondary ion mass spectrometry (D-SIMS) ionized by co-sputtering with C60+ and Ar+

Dynamic secondary ion mass spectrometry (D-SIMS) analysis of poly(ethylene terephthalate) (PET) and poly(methyl methacrylate) (PMMA) was conducted using a quadrupole mass analyzer with various combinations of continuous C(60)(+) and Ar(+) ion sputtering. Individually, the Ar(+) beam failed to generate fragments above m/z 200, and the C(60)(+) beam generated molecular fragments of m/z ~1000. By combining the two beams, the auxiliary Ar(+) beam, which is proposed to suppress carbon deposition due to C(60)(+) bombardment and/or remove graphitized polymer, the sputtering range of the C(60)(+) beam is extended. Another advantage of this technique is that the high sputtering rate and associated high molecular ion intensity of the C(60)(+) beam generate adequate high-mass fragments that mask the damage from the Ar(+) beam. As a result, fragments at m/z ~900 can be clearly observed. As a depth-profiling tool, the single C(60)(+) beam cannot reach a steady state for either PET or PMMA at high ion fluence, and the intensity of the molecular fragments produced by the beam decreases with increasing C(60)(+) fluence. As a result, the single C(60)(+) beam is suitable for profiling surface layers with limited thickness. With C(60)(+)-Ar(+) co-sputtering, although the initial drop in intensity is more significant than with single C(60)(+) ionization because of the damage introduced by the auxiliary Ar(+), the intensity levels indicate that a more steady-state process can be achieved. In addition, the secondary ion intensity at high fluence is higher with co-sputtering. As a result, the sputtered depth is enhanced with co-sputtering and the technique is suitable for profiling thick layers. Furthermore, co-sputtering yields a smoother surface than single C(60)(+) sputtering.     

Synthesis and characterization of a new chromophor with acid/base-sensitive fluorescence emission

A new two-photon absorption compound,2-{4-((dicyanomethylidene-5,5-dimethylcyclohexl)vinyl]phenyl}imidazo[4,5- f][l,10]phenanthroline(DDVPIP),was synthesized and characterized.The one-photon excited fluorescence(OPEF) and two-photon excited fluorescence(TPEF) of DDVPIP are sensitive to the acid/base of the solution,which arc enhanced in basic solution but weakened in acidic solution.Charge-transfer(CT) states of DDVPIP were calculated through theory methods to explain its acid/ base-sensitive fluorescent properties.     

The influence of different fabrication processes on characteristics of excess Bi2O3-doped 0.95 (Na0.5Bi0.5)TiO3–0.05 BaTiO3 ceramics

In this study, we will develop the influences of the excess x wt% (x=0, 1, 2, and 3) Bi₂O₃-doped and the different fabricating process on the sintering and dielectric characteristics of 0.95 (Na_0.5Bi_0.5)TiO₃–0.05 BaTiO₃ ferroelectric ceramics with the aid of SEM and X-ray diffraction patterns, and dielectric–temperature curves. The 0.95 (Na_0.5Bi_0.5)TiO₃–0.05 BaTiO₃+x wt% Bi₂O₃ ceramics are fabricated by two different processes. The first process is that (Na_0.5Bi_0.5)TiO₃ composition is calcined at 850 °C and BaTiO₃ composition is calcined at 1100 °C, then the calcined (Na_0.5Bi_0.5)TiO₃ and BaTiO₃ powders are mixed in according to 0.95 (Na_0.5Bi_0.5)TiO₃–0.05 BaTiO₃+x wt% Bi₂O₃ compositions. The second process is that the raw materials are mixed in accordance to the 0.95 (Na_0.5Bi_0.5)TiO₃–0.05 BaTiO₃+x wt% Bi₂O₃ compositions and then calcining at 900 °C. The sintering process is carried out in air for 2 h from 1120 to 1240 °C. After sintering, the effects of process parameters on the dielectric characteristics will be developed by the dielectric–temperature curves. Dielectric–temperature properties are also investigated at the temperatures of 30–350 °C and at the frequencies of 10 kHz–1 MHz.     

Anisotropic power-law inflation of the five dimensional scalar–vector and scalar-Kalb–Ramond model

We will study the cosmological implications of the five dimensional scalar–vector and scalar-Kalb–Ramond model. In particular, a new set of Bianchi type I power-law analytic solution will be obtained for this model. The cosmic no-hair conjecture can be shown to break down in the presence of the scalar–vector and scalar-Kalb–Ramond couplings. The effect of the Kalb–Ramond field in the presence of the power-law solution will be shown explicitly. We will also show that the presence of a phantom field does, however, destabilize the corresponding Bianchi type I power-law inflationary solutions.     

1,4-二(2-苯并(口恶)唑基)苯及其衍生物紫外光谱和荧光光谱的溶剂效应

测定了1,4-二(2-苯并(口恶)唑基)本及其5,5′-二取代衍生物共八种化合物在十五种溶剂中的紫外吸收光谱及1,4-二(2-苯并(口恶)唑基)苯在九种溶剂中的荧光发射光谱。用二元回归分析和两类溶剂参数的双参数方程处理数据,得到了较一元回归和单参数方程更好的相关关系。     

RESEARCH ON 2-(2'-SUBSTITUTED VINYL)-5-BIPHENYLYL OXAZOLES

Fifteen of the 2-(2'-substituted vinyl)-5-biphenylyl oxazoles were synthesized respectively by the condensation of corresponding 2-methyl-5-biphenylyl oxazole with benzaldehyde,substituted benzaldehydes or furfural in the presence of alkali or acid.Their m.p.,infrared spectra,λmax of UV spectra and fluorescence spectra,fluorescence quantum yields as well as laser conversion efficiency of the compounds are listed in tables.     

高分辨超导NMR谱仪的匀场

本文详细叙述了超导磁体的磁场分布和匀场线圈的设计。并对匀场电源、匀场线圈的精度和稳定性等要求作了估算。     

交流示波极谱滴定的研究(Ⅻ)——中和滴定

本文系统地报导了交流示波极谱滴定在中和滴定中的应用,解决了弱酸弱碱在水溶液中直接滴定等问题。同时提出了中和滴定的两大类指示剂的概念,并且总结了它们的性质。因此,示波极谱中和滴定将大大地丰富中和滴定的内容,扩大其应用范围。     

2,6-二取代苯并二噁唑的研究(Ⅴ)

合成了21种在苯基上间位和邻位取代的2,6-二取代苯基苯并二噁唑,测定了化合物的熔点、紫外吸收光谱、萤光发射光谱及激光性能,并讨论了这些化合物的结构与光性能之间的关系。