金属羰基化合物[CpFe(CO)_2]_2与金属氧化物表面作用的傅里叶变换漫反射和光声红外光谱研究

用漫反射红外光谱和光声红外光谱法研究了金属羰基化合物［ＣｐＦｅ（ＣＯ）２］２Ｃｐ＝η５—Ｃ５Ｈ５与酸性、中性和碱性Ａｌ２Ｏ３及ＴｉＯ２的相互作用。结果表明，在Ａｌ２Ｏ３表面生成的衍生物种类及浓度与Ａｌ２Ｏ３的酸碱度明显相关。在酸性Ａｌ２Ｏ３表面，主要存在衍生物［ＣｐＦｅ（ＣＯ）２Ｆｅ—Ｈ—Ｆｅ（ＣＯ）２Ｃｐ］＋及少量的ＣｐＦｅ（ＣＯ）２（—Ｏ—）；在中性Ａｌ２Ｏ３表面存在ＣｐＦｅ（ＣＯ）２（—Ｏ—）及较少的［ＣｐＦｅ（ＣＯ）］４；而在碱性Ａｌ２Ｏ３表面主要衍生物为［ＣｐＦｅ（ＣＯ）］４及少量ＣｐＦｅ（ＣＯ）２（—Ｏ—）。衍生物的相对浓度以酸性Ａｌ２Ｏ３表面最高，碱性Ａｌ２Ｏ３表面最低。在ＴｉＯ２表面，［ＣｐＦｅ（ＣＯ）２］２结构基本未变，在空气中比较稳定，没有观察到衍生物的生成。测定了［ＣｐＦｅ（ＣＯ）２］２及其在ＴｉＯ２表面近红外漫反射光谱，指认了大部分观察到的光谱为羰基振动的合频和倍频，并尝试指认了少数光谱为高级（三级）倍频和多元组频（合频）。     

漫反射FTIRS定量分析法测定诺氟沙星胶囊的含量

采用漫反射红外定量分析技术测定了诺氟沙星胶囊的含量，可排除辅料的影响，且吸光度与诺氟沙星的浓度呈良好的线性关系，平均回收率为98．23％，RSD为1．56％。方法简便、准确、可靠，可用于诺氟沙星胶囊的含量测定。     

Nonadiabatic fragmentation of excited molecular ions: An exploratory study for

The photodissociation of was studied in a one-dimensional approximation, with the aim of understanding the nonadiabatic features of the fragmentation dynamics. In the collinear arrangement of the system, the three lowest excited surfaces (states) interact via two avoided crossings outside the Franck-Condon region, and they are strongly coupled radially by nonadiabatic terms. Electronic transition probabilities for the process , with in one of the three lowest electronic states involved in the fragmentation, were calculated using the semiclassical multichannel S-matrix within the half-collision approach to photodissociation. The reliability of the semiclassical theory, for treating multichannel nonadiabatic processes was analyzed, and inelastic cross-sections for the three processes of electronically selected fragmentations were calculated. The structure found in the calculated absorption lineshapes reveals the marked influence of the nonadiabatic couplings between excited states in the fragmentation dynamics of this molecular ion. Received: 6 March 1998 / Revised: 7 March 1998 and 17 June 1998 / Accepted: 23 June 1998     

Diffuse interstellar bands: a comprehensive laboratory study

As a result of the search for the identity of the chromophores responsible for producing the diffuse interstellar bands, a comprehensive exposition of experimental data is presented, which implicates the following molecules: (1) The extremely stable organic molecules, magnesium tetrabenzoporphyrin (MgTBP) and H(2)TBP. (2) A paraffin matrix (referred to as "grains") containing TBPs. (3) A low concentration of pyridine (also within the grains), whose transmission window at 2175 A, accounts for the ubiquitous UV bump. The blue emission spectra associated with the central star, HD44179, of the Red Rectangle displays the fluorescence excitation spectra of bare MgTBP. This unique spectrum matches the low temperature lab data of MgTBP in the vapor phase. An effective grain temperature of 2.728 K (+/-0.008) was deduced, based on MgTBP's lowest measured vibrational state of 341 GHz.     

Diffuse scattering from fullerenes

Fullerene solids exhibit textbook examples of orientational freezing transitions, i.e. structural transitions from a high temperature phase, where the molecules undergo rapid reorientation, to a low temperature phase where the molecules are locked-in into discrete orientations. In general, even low temperature phases are not completely ordered because of frozen-in orientational disorder, partly also because of a high density of stacking faults. Diffuse scattering has been used extensively to characterize both dynamic and static disorder in fullerene solids. A review is given on the experimental results as well as on the various techniques employed to analyze the data.     

Diffuse Reflectance Spectrum of Cupric Oxide

The diffuse reflectance spectrum of cupric oxide (GuO) powder in the region 300–1000 mμ. has already been studied^1,2. In the present communication, the diffuse reflectance spectra of both pure and diluted cupric oxide powder samples have been reported. In the present work, the region of investigation has also been extended down to 200 mμ.     

Diffuse reflectance spectroscopy for monitoring diabetic foot ulcer – A pilot study

Foot ulceration due to diabetes mellitus is a major problem affecting 12–25% of diabetic subjects in their lifetime. An untreated ulcer further gets infected which causes necrosis leading to amputation of lower extremities. Early identification of risk factors and treatment for these chronic wounds would reduce health care costs and improve the quality of life for people with diabetes. Recent clinical investigations have shown that a series of factors including reduced oxygen delivery and disturbed metabolism have been observed on patients with foot ulceration due to diabetes. Also, these factors can impair the wound healing process. Optical techniques based on diffuse reflectance spectroscopy provide characteristic spectral finger prints shed light on tissue oxygenation levels and morphological composition of a tissue. This study deals with the application of diffuse reflectance intensity ratios based on oxyhemoglobin bands (R542/R580), ratios of oxy- and deoxy-hemoglobin bands (R580/R555), total hemoglobin concentration and hemoglobin oxygen saturation between normal and diabetic foot ulcer sites. Preliminary results obtained are found to be promising indicating the application of reflectance spectroscopy in the assessment of foot ulcer healing.     

采用中子衍射实验解析PbS的原子间力常数

使用日本原子能研究开发机构里设置的高分解能粉末中子衍射装置, 在 15 K 和 294 K 温度下对 PbS 进行了中子衍射实验。在 15 K 和 294 K 温度里观察到了明显的振动形状的热漫散射。 所观察到的漫散射强度可由原子间热振动相关效应的影响来解释。在 294 K 下从原子间相关效应和德拜—劳厄因子的温度参数中获得了 PbS 相邻原子间的力常数。     

A diffuse‐interface modeling for liquid solution–solid gel phase transition of physical hydrogel with nonlinear deformation

A diffuse‐interface model is presented in this paper for simulation of the evolution of phase transition between the liquid solution and solid gel states for physical hydrogel with nonlinear deformation. The present domain covers the gel and solution states as well as a diffuse interface between them. They are indicated by the crosslink density in such a way that the solution phase is identified as the state when the crosslink density is small, while the gel as the state if the crosslink density becomes large. In this work, a novel order parameter is thus defined as the crosslink density, which is homogeneous in each distinct phase and smoothly varies over the interface from one phase to another. In this model, the constitutive equations, imposed on the two distinct phases and the interface, are formulated by the second law of thermodynamics, which are in the same form as those derived by a different approach. The present constitutive equations include a novel Ginzburg–Landau type of free energy with a double‐well profile, which accounts for the effect of crosslink density. The present governing equations include the equilibrium of forces, the conservations of mass and energy, and an additional kinetic equation imposed for phase transition, in which nonlinear deformation is considered. The equilibrium state is investigated numerically, where two stable phases are observed in the free energy profile. As case studies, a spherically symmetrical solution‐gel phase transition is simulated numerically for analysis of the phase transition of physical hydrogel.     

Flow injection visible diffuse reflectance quantitative analysis of nickel

Flow injection (FI) methodology, using diffuse reflectance in the visible region of the spectrum, for the analysis of nickel, precipitated in the form of dimethylglyoximate, is presented. A reflectance cell, constructed in polytetrafluoroethylene, using a LED (light emitting diode) as light source and a LDR (light dependent resistor) as detector, is described. The analytical signal (S) correlates with nickel concentration (C) between 1.6 × 10⁻⁴ and 6.6 × 10⁻⁴ mol L⁻¹. This correlation is described by the equation S = −1.108 + 3.314 × 10⁴C − 2.081 × 10⁷C² (r = 0.9996). The experimentally observed limit of detection is about 1.3 × 10⁻⁴ mol L⁻¹, as in lower concentrations the formation of precipitate is not observed. The experimental quantitation limit is about 1.6 × 10⁻⁴ mol L⁻¹. The mean R.S.D. (relative standard deviation) is about 2.7%. Samples containing nickel were analyzed and the results obtained in this method were compared with those of other methods using the statistical Student's t-test.