Time-Resolved Photoacoustic Calorimetry: From Carbenes to Proteins

Why have molecules only been seen but not heard? For over a century chemists have probed reactions with various spectroscopic methods to learn about structures, dynamics, and reactivities of their molecules. What they have not done is to listen to their molecules react. Although the photoacoustic phenomenon has been known since 1880, it is only in the last twenty years that technology has developed to the point where sound waves produced by reacting molecules can be time resolved and the information contained within the waves deciphered. The information content within the photoacoustic wave is indeed rich, for one can learn about the dynamics and the magnitude of enthalpy changes associated with the reaction as well as the changes in molecular volume. This review article chronicles the development of time-resolved photoacoustic calorimetry and its application to a variety of reactions encountered in organic and organometallic chemistry and biochemistry.     

Synthesis and Crystal Structure of Di-n-butyltin(IV) Complex with 2-Oxo-propionic Acid (4-Pyridinecarbonyl) Hydrazone

Introduction The studies of diorganotin(IV) complexes are of current interest owing to their wide range of applica-tions such as biocides and homogeneous catalysts in industry.1 In recent years there have been more and more reports on the synthesis, antitumour activities and structural elucidation of various diorganotin(IV) deriva-tives of carboxylic acid.2-5 In particular, people take considerable interest in structural studies of diorgano-tin(IV) complexes of carboxylic acid, because there…     

Formulation of N- and ν-representable density functional theory. V. Exchange-only self-consistent field

The concept of a self-consistent field is developed within the version of density functional theory based on local-scaling transformations. It is shown that in this context there arise two types of consistency: one relating to the charge-consistency within an orbit and another to “orbit jumping.” The latter is analyzed in terms of one-particle equations. The connection with other methods is discussed. © 1992 John Wiley & Sons, Inc.     

Surface plasmon-polaritons and their uses

Surface plasmon-polaritons have been experimentally and theoretically studied for many years but in recent years interest has grown substantially due to their possible use in novel device applications. The aim of this review is to introduce the concept of surface plasmon-polaritons so that the reader will be able to appreciate the physics they can probe, and the device applications in which they may be utilized.     

Local solution for the Kadomtsev-Petviashvili equation with periodic conditions

In this article we prove a local existence and uniqueness theorem for the Kadomtsev-Petviashvili Equation (u _t +u _xxx +uu _x ) _x −u _yy =0) in the Sobolev spaces of orders≥3, with initial values in the same spaces, and periodic boundary conditions. This theorem improves previous results based upon the application of singular perturbation techniques.     

Molecular weight dependence of diblock copolymer segregation at a polymer/polymer interface

Utilizing forward recoil spectrometry (FRES), we have determined the segregation isotherm which describes the interfacial excess z_i^* of diblock copolymers of poly (d₈-styrene-b-2-vinylpyridine) (dPS-PVP) at the interface between the homopolymers PS and PVP as a function of ?_∞, the volume fraction of diblock copolymer remaining in the host homopolymer. All the samples were analyzed after annealing at temperatures and times sufficient to achieve equilibrium segregation. The effect of the degree of polymerization of both the diblock copolymers and the host homopolymers on the segregation isotherm is investigated. When the degree of polymerization of the homopolymer is much larger than that of the diblock copolymer, the normalized interfacial excess (z_i^*/R_g), where R_g is the radius of gyration of an isolated block copolymer chain, is a universal function of that portion of the block copolymer chemical potential due to chain stretching. The existence of such a universal function is predicted by theory and its form is in good agreement with self-consistent mean field calculations. Using these results, one can predict important aspects of the block copolymer segregation (e.g., the saturation interfacial excess) without recourse to the time-consuming numerical calculations. © 1994 John Wiley & Sons, Inc.     

Schiff碱水杨醛苯甲酰腙的特性

研究了 Schiff碱水杨醛苯甲酰腙 (简称 SBH)晶体在 DMSO及其 DMSO- H2 O的混合溶剂中的红外光谱 ,通过 SBH氘代前后的 IR对比发现 ,羟基氢质子与混合溶剂 DMSO- H2 O(3∶ 1 ,V/ V)产生较大的相互作用。向溶有 SBH的 75 % DMSO- 2 5 % H2 O的溶液滴加 KOH发现 ,SBH分子上的 C O羰基基团先与 KOH作用 ,其后与 O H 羟基基团作用