There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Partial leastgquares (PLS) methods for spectral analyses are related to other multlvarlate callbratlon methods such as classical least-squares (CLS), Inverse least-squares (ILS), and prlnclpal component regression (PCR) methods which have been used often In quantitative spectral analyses. The PLS method which analyzes one chemlcal component at a tbne Is presented, and the basis for each step In the algorithm Is explained. PLS callbratlon Is shown to be composed of a series of simpllfled CLS and ILS steps. This detalled understandlng of the PLS algorithm has helped to ldentlfy how chemically Interpretable qualltatlve spectral lnformatlon can be obtained from the lntennedlate steps of the PLS algorithm. These methods for extractlng qualitative Information are demonstrated by use of simulated spectral data. The qualltatlve Information directly available from the PLS analysis Is superlor to that obtained from PCR but is not as complete as that which can be generated during CLS analyses. Methods are presented for selecting optbnal numbers of loading vectors for both the PLS and PCR models In order to optimize the model while simultaneously reduclng the potential for overfittlng the caHbratlon data. Outlier detection and methods to evaluate the statlstlcal slgnlflcance of resuits obtalned from the dMerent cahatlon methods applied to the same spectral data are also discussed.

/pdf/partial-least-squares-methods-for-spectral-analyses-1-125ka44fdl.pdf

Partial least-squares methods for spectral analyses. 1. Relation to other quantitative calibration methods and the extraction of qualitative information

This paper provides a third update to the review of reversible deactivation radical polymerization (RDRP) achieved with thiocarbonylthio compounds (ZC(=S)SR) by a mechanism of reversible addition-fragmentation chain transfer (RAFT) that was published in June 2005 (Aust. J. Chem. 2005, 58, 379). The first update was published in November 2006 (Aust. J. Chem. 2006, 59, 669) and the second in December 2009 (Aust. J. Chem. 2009, 62, 1402). This review cites over 700 publications that appeared during the period mid 2009 to early 2012 covering various aspects of RAFT polymerization which include reagent synthesis and properties, kinetics and mechanism of polymerization, novel polymer syntheses, and a diverse range of applications. This period has witnessed further significant developments, particularly in the areas of novel RAFT agents, techniques for end-group transformation, the production of micro/nanoparticles and modified surfaces, and biopolymer conjugates both for therapeutic and diagnostic applications.

/pdf/living-radical-polymerization-by-the-raft-process-a-second-3rre2ur7xt.pdf

Living Radical Polymerization by the RAFT Process - A Second Update

FTIR techniques in clay mineral studies

2.3. Ionic Liquids (ILs) 5374 2.4. Complexation Reactions on Oxidized CNTs 5375 2.5. Halogenation 5376 2.6. Cycloaddition Reactions 5377 2.7. Radical Additions 5379 2.8. Nucleophilic Additions 5381 2.9. Electrophilic Additions 5381 2.10. Electrochemical Modifications 5381 2.11. Plasma-Activation 5381 2.12. Mechanochemical Functionalizations 5382 3. Noncovalent Interactions 5382 3.1. Polynuclear Aromatic Compounds 5382 3.2. Interactions with Other Substances 5384 3.3. Interactions with Biomolecules 5385 4. Endohedral Filling 5386 4.1. Encapsulation of Fullerenes 5386 4.2. Encapsulation of Organic Substances 5387 4.3. Encapsulation of Inorganic Substances 5387 5. Decoration of CNTs with Metal Nanoparticles 5388 5.1. Covalent Linkage 5388 5.2. Direct Formation on Defect Sites 5388 5.3. Electroless Deposition 5388 5.4. Electrodeposition 5389 5.5. Chemical Decoration 5390 5.6. Deposition of Nanoparticles onto CNTs 5391 5.7. π-π Stacking and Electrostatic Interactions 5391 6. Concluding Remarks 5392 7. Acknowledgments 5392 8. References 5392

Current progress on the chemical modification of carbon nanotubes.

Interactions between alginate and chitosan biopolymers characterized using FTIR and XPS.

Surface-enhanced Raman spectroscopy of amino acids adsorbed on an electrochemically prepared silver surface

Surface-enhanced Raman spectroscopy of peptides and proteins adsorbed on an electrochemically prepared silver surface

Ultrasonically initiated, in situ emulsion polymerization was used to prepare multiwalled carbon nanotube/polyaniline composites (MWNTs/PANI). Transmission electron microscopy (TEM) showed that the nanotubes were coated with a PANI layer, with the thickness of this coating varying with the content of carbon nanotubes and polymerization conditions. Whereas polyaniline/carbon nanotube composite particles prepared by the conventional stirring method have a highly structured, nodular morphology, ultrasonic initiation leads to long, thin, polymer-wrapped tubes. In the case of ultrasonically initiated in situ emulsion polymerization, Fourier transform infrared (FTIR) spectra suggested that site-selective interactions between the quinoid ring of the PANI and the MWNTs facilitate charge-transfer between the two components. In such composites, CNT improved the polymer properties, such as thermal stability, as determined by thermogravimetric analysis and conductivity measured using the four-probe method.

Synthesis of New Polyaniline/Nanotube Composites Using Ultrasonically Initiated Emulsion Polymerization

A method is presented which allows the FT-IR spectrum of a material to be related to many of the significant practical properties of that material. The method uses factor analysis of all or part of the spectra of a calibration set of well-characterized samples to determine the minimum set of factors and the associated factor loadings required to reproduce the spectra. Multiple linear regression of the factor loadings against measured properties gives close correlations which are used to predict the properties of unknown samples similar to those constituting the base set. The method is often fast compared with conventional techniques and, by suitable choice of calibration sets, can give semiquantitative results for a widely varying set of samples, or quantitative results of accuracy comparable with conventional techniques for a calibration set and unknowns from a narrower range of samples. Examples of the use of the method are given for coal, bauxite, manganese dioxide ore, and diesel fuel.

Peter M. Fredericks

Papers

Interactions between alginate and chitosan biopolymers characterized using FTIR and XPS.

Surface-enhanced Raman spectroscopy of amino acids adsorbed on an electrochemically prepared silver surface

Surface-enhanced Raman spectroscopy of peptides and proteins adsorbed on an electrochemically prepared silver surface

Synthesis of New Polyaniline/Nanotube Composites Using Ultrasonically Initiated Emulsion Polymerization

Materials Characterization Using Factor Analysis of FT-IR Spectra. Part 1: Results