High-precision articles

Eor processing after sintering, in the least expensive method for sintered PTEE tape or sheet, a large billet is skived on a lathe after it has been sintered and cooled. High precision articles are machined from ram-extmded rods. 

The possibilities of using polysulfones in parts of high-precision articles arise from its low shrinkage (0.7%) and low water absorption (0.22% after 5.64 X10 sec). 

Flow cytometry is a high-precision technique for rapid analysis and sorting of cells and particles. The principles underlying flow cytometry are discussed in many comprehensive review articles (3-5) and will only be touched on here. This fluorescent detection technique provides statistical accuracy, reproducibility, and sensitivity, as well as allowing the simultaneous measurement of multiple parameters on a cell-to-cell basis. Information is derived from the optical responses of... 

Two alternatives would seem to be open in the discussion of this subject. An exhaustive account of known gelling behavior would inevitably result in a technical bias. On the other hand, it should be possible to emphasize the principles, and to illustrate the limits of present understanding by chosen examples. The choice has been made reluctantly, because both types of discussion would be timely, but it would seem more sensible to marshal our ideas about the basis of gel formation before attempting to tabulate and organize the sum of factual knowledge. The present article is written from the viewpoint of the structural chemist who wishes to see how the overall properties of the gel are an outcome of molecular structure, and who would rather have a qualitative understanding in these terms than a physical or mathematical model which, even if capable of predictions with high precision, did not start from the molecular formula. ... 

Density functional techniques are available for the calculation of the molecular and electronic structures of ground state systems. With the functionals available today, these compete with the best ab initio methods. This article focuses on the theoretical aspects associated with the Kohn Sham density functional procedure. While there is much room for improvement, the Kohn-Sham exchange-correlation functional offers a great opportunity for theoretical development without returning to the uniform electron gas approximation. Theoretical work in those areas will contribute significantly to the development of new, highly precise density functional methods. 

Hartwell, S. K. and K. Grudpan, 2012. Flow-based systems for rapid and high-precision enzyme kinetics studies. J. Anal. Methods Chem. 2012, Article ID 450716, 10pp. doi 10.1155/2012/450716. 

Because ENDOR leads to a direct determination of hyperfine splittings via the nuclear moment, its resolution is some 2000 times greater than in a conventional ESR spectrum for the same system. As a result, information which might otherwise remain hidden beneath a broad ESR line may be extracted with high precision. An excellent and very readable review of ENDOR, with special application to the iron-sulfur proteins, may be found in the article by Orme-Johnson and Sands (1973) and the paper by Fritz et al (1971). These two articles give excellent accounts of the relaxation effects involved. 

The term particle and particle size are so highly ambiguous as to require precise definition. As used in this article particles will.be limited by size to those distinct entities which have physically detectable boundaries in any direction within the limits of 0.05 and 10 microns (1 micron, p -0.001mm). This size range covers those particles which can be directly measured without magnification down to those which exhibit colloidal behavior... 

Immunoassays designed for environmental applications are mostly sold as some variation of the ELISA format. ELISA-like formats dominate the field because they are inexpensive and because they provide high sensitivity and precision without requiring complex instrumentation. The basic ELISA format supports both field and laboratory-based applications but is limited by multiple steps and inadequate sensitivity for some applications, excessive variability and sometimes long analysis times. Some of the other formats discussed in this article may replace the ELISA for selected applications however, because many laboratories are familiar with the ELISA technology, there will be a significant delay before alternative formats are widely accepted. 

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