The Mathematical Theory of Ito Diffusions on Hypersurfaces, with Applications to NMR Relaxation Problems

A mathematical framework for translational Brownian motion on hypersurfaces is presented, using an imbedding of the surface and Ito diffusions in the ambient space. This includes a survey of Ito calculus and differential geometry. Computational methods for time correlation functions relevant to spin relaxation studies on curved interfaces are given, and explicit calculations of time correlation functions and order parameters for a Rippled surface are presented.     

Crystal chemistry of protonated 1,2-bis(di-R-aminomethyl)benzenes. Part V. [1,2-bis(diethylaminomethyl)-3,6-dichlorobenzene:1,2-bis(diethylaminomethyl)-3,4,6-trichlorobenzene]perchlorate mixed crystals

The mixed crystals of 1,2-bis(diethylaminomethyl)-3,6-di- and 3,4,6-trichloro-benzene perchlorate at 0.5:0.5 ratio have been studied using X-ray diffraction and FT-IR spectroscopy. The molecules of di- and tri-chloro derivatives are distributed randomly in the crystal lattice; however, this disorder manifested mainly by a partial occupation of the chlorine atom at C(4) and by relatively big atomic temperature parameters even at 99 K, particularly for the oxygens of the perchlorate anion. The proton in the [NHN]⁺ bond refined close to the equidistant position between the nitrogens. The conformations of the diethylaminomethyl substituents are pseudo-symmetrical relative to the plane and twofold axis passing through the midpoint of the hydrogen bond. The IR spectrum of the crystals shows a broad intense band and an intense continuous absorption indicating relatively high proton polarizability in the intramolecular hydrogen bond. In acetonitrile and in chloroform, the proton in the intramolecular hydrogen bond also shows a very high proton polarizability demonstrated by the continuous absorption in the IR spectrum.     

EPR spectroscopy on irradiated nickel tetracyanide in NaCl host lattice: mechanism for the simultaneous formation of reduced and oxidized species

The kinetics of oxidized and reduced Ni²⁺ complexes produced by X-ray irradiation on single crystals of NaCl doped with [Ni(CN)₄]²⁻ is studied by Electron Paramagnetic Resonance at room temperature. The interdependent generation of these two complexes is attributed to migration of the charge compensating vacancy from the reduced to the oxidized complex in a reversible reaction. At higher X-ray doses, there is a predominant formation of the reduced complex.     

Practical uses of FTIR spectroscopy in wood science and technology

Based on own research activities this survey demonstrates the potential applications of FTIR spectroscopy in wood and wood-product research. This rapid method can be used e.g. with success for determination of lignin in woody materials and pulps. Crucial analytical data of lignins were also determined by quantitative evaluation of FTIR data. The degree of substitution of cellulose derivatives can be estimated. The course of delignification during pulping was monitored using transmission and circular ATR cells for the IR spectroscopy of the cooking liquors. Based on these spectra the Kappa number of pulps can be predicted.     

Use of FTIR spectroscopy in the investigation of catalytic reactions in zeolites—Possibilities and limitations

FTIR-spectroscopic investigations of catalytic reactions yield detailed information about the interaction of adsorbed molecules with the catalyst and kinetic data of the surface reaction, if the participating molecules show vibrations whose position and intensity in the IR-spectrum depend on the sorption state and the quantity adsorbed. In this paper, the possibilities and limitations of the method are represented by two examples.     

牛血清白蛋白与十二烷基硫酸钠作用的机理

利用电动势法得到了牛血清白蛋白(BSA)与十二烷基硫酸钠(SDS)相互作用的结合等温线. 通过四阶导数紫外光谱法和荧光光谱法研究了相互作用过程中芳香族氨基酸残基微环境极性的变化. 通过研究发现, 随着SDS浓度的逐渐增大, SDS在BSA上的平均结合数(v)逐渐增大, 色氨酸(Trp)残基所处微环境的极性在减弱后保持基本不变, 酪氨酸残基所处微环境的极性在明显增强后稍有减弱, 苯丙氨酸残基所处微环境的极性略有增强. 结果表明, 当v由0增大到14时, SDS主要结合在BSA的Trp-213附近并逐渐形成聚集体, 从而诱导BSA由结构域ⅡA 开始逐渐展开. 此后, SDS呈正协同作用的特点与BSA 结合, v急剧增大. 当v约为302 时, SDS在BSA上的结合基本达到饱和, BSA的构象趋于稳定.     

Small-angle X-ray study of air-dried elastoidin using three- and one- dimensional correlation functions obtained from slit-smeared intensity

In the present paper an isotropic sample of air-dried elastoidin has been studied considering it to be a non-ideal two-phase densely packed system after the theories by Vonk [1]. The relevant important physical parameters obtained for the sample areE, the width of the transition layer,D, the average periodicity transverse to the layers, S/V, the specific inner surface ₁ and ₂, the volume fraction of two phases, i. e. matter and void,l ₁ andl ₂ the transversal lengths,l _r, the range of inhomogeneity,l _c, the length of coherence and 2E/D, the volume fraction of the transition layer. The values ofE obtained by two approches as given by Vonk [1] and Ruland [2] show but a small difference indicating the correctness of the analysis.     

Heteronuclear Nickel‐Iron Complexes and the Crystal Structure of [Fe2(CO)6(μ3‐S)2{Ni(dppe)}]

A series of heteronuclear nickel‐iron complexes [Fe₂(CO)₆(μ‐SH)(μ₃‐S){NiCl(PPh₃)₂}] ( 1 ), [Fe₂(CO)₆(μ‐SH)(μ₃‐S){NiCl(dppe)}] ( 2 ), [Fe₂(CO)₆(μ₃‐S)₂{Ni(PPh₃)₂}] ( 3 ), [Fe₂(CO)₆(μ₃‐S)₂{Ni(dppe)}] ( 4 ) and [Fe₂(CO)₆(μ‐SPh)(μ₃‐S){NiCl(dppe)}] ( 5 ) have been prepared. The structure of 4 has been determined by X‐ray crystallography. The central metal‐sulfur core of 4 has a trigonal bipyramidal shape with a NiFe₂ base plane with two axial sulfur atoms. Each iron atom is 5‐coordinate forming a distorted square pyramid; the nickel is square planar coordinated by two sulfur atoms and two phosphorus atoms.     

Validation of a direct non-destructive quantitative analysis of amiodarone hydrochloride in Angoron formulations using FT-Raman spectroscopy

Raman spectroscopy was applied for the direct non-destructive analysis of amiodarone hydrochloride (ADH), the active ingredient of the liquid formulation Angoron^®. The FT-Raman spectra were obtained through the un-broken as-received ampoules of Angoron^®. Using the most intense vibration of the active pharmaceutical ingredient (API) at 1568 cm⁻¹, a calibration model, based on solutions with known concentrations, was developed. The model was applied to the Raman spectra recorded from three as-purchased commercial formulations of Angoron^® having nominal strength of 50 mg ml⁻¹ ADH. The average value of the API in these samples was found to be 48.56 ± 0.64 mg ml⁻¹ while the detection limit of the proposed technique was found to be 2.11 mg ml⁻¹. The results were compared to those obtained from the application of HPLC using the methodology described in the European Pharmacopoeia and found to be in excellent agreement. The proposed analytical methodology was also validated by evaluating the linearity of the calibration line as well as its accuracy and precision. The main advantage of Raman spectroscopy over HPLC method during routine analysis is that it is considerably faster and no solvent consuming. Furthermore, Raman spectroscopy is non-destructive for the sample. However, the detection limit for Raman spectroscopy is much higher than the corresponding for the HPLC methodology.     

Synthesis and structural characterization of a coordination polymer of silver(I) with saccharinate and nicotinamide

A silver(I)-saccharinato (sac) complex with nicotinamide (nia), [Ag(sac)(nia)] _n has been synthesized and characterized by elemental analysis, IR spectroscopy, DTA-TG analyses and single crystal X-ray diffractometry. The complex crystallizes in monoclinic space group P2₁/n with unit cell parameters of a=7.0258(4) Å, b=24.3784(10) Å, c=8.4301(5) Å, β=109.407(5)°, V=1361.85(13) ų and Z=4. [Ag(sac)(nia)] _n contains [Ag(sac)(nia)] units, which are doubly bridged by both nia and sac ligands, leading to a linear one-dimensional polymeric chains running along the a axis. The silver(I) ion has a highly distorted AgN₂O₂ tetrahedral geometry and the coordination polymer exhibits relatively short intra-chain ligand supported Ag···Ag separations of 3.1593(4) Å. The one-dimensional chains are crosslinked by N–H···O hydrogen bonds and aromatic π(sac)···π(nia) stacking interactions to generate a two-dimensional layer structure. IR spectra and thermal analysis data are in agreement with the crystal structure.