Basic Concepts of Stimulated Emission and Lasing in Organic Materials

Ultimate resolution in the scanning electron microscope is determined not only by the diameter of the incident electron beam, but by interaction of that beam with the specimen material. Generally, while minimum beam diameter diminishes with increasing voltage, due to the reduced effect of aberration component and magnetic interference, the excited volume within the sample increases with electron energy. Thus, for any given material and imaging signal, there is an optimum volt age to achieve best resolution.In the case of organic materials, which are in general of low density and electric ally non-conducting; and may in addition be susceptible to radiation and heat damage, the selection of correct operating parameters is extremely critical and is achiev ed by interative adjustment.

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200kv superconducting cryo electron microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100127645 ◽

1987 ◽

Vol 45 ◽

pp. 642-643

Author(s):

M. Iwatsuki ◽

Y. Kokubo ◽

Y. Harada ◽

J. Lehman

Keyword(s):

Electron Microscope ◽

Structure Analysis ◽

Organic Materials ◽

Strong Interactions ◽

Specimen Preparation ◽

Great Effort ◽

Electron Microscopic ◽

Crystal Fields ◽

Special Skill ◽

Long Time

In recent years, the electron microscope has been significantly improved in resolution and we can obtain routinely atomic-level high resolution images without any special skill. With this improvement, the structure analysis of organic materials has become one of the interesting targets in the biological and polymer crystal fields.Up to now, X-ray structure analysis has been mainly used for such materials. With this method, however, great effort and a long time are required for specimen preparation because of the need for larger crystals. This method can analyze average crystal structure but is insufficient for interpreting it on the atomic or molecular level. The electron microscopic method for organic materials has not only the advantage of specimen preparation but also the capability of providing various information from extremely small specimen regions, using strong interactions between electrons and the substance. On the other hand, however, this strong interaction has a big disadvantage in high radiation damage.

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STM of freeze-fracture replicas: Problems and promises

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100146187 ◽

1993 ◽

Vol 51 ◽

pp. 68-69

Author(s):

J. T. Woodward ◽

J. A. N. Zasadzinski

Keyword(s):

Scanning Tunneling Microscope ◽

Organic Materials ◽

Freeze Fracture ◽

Atomic Resolution ◽

Scanning Tunneling ◽

Tunneling Microscope ◽

Molecular Scale ◽

Organic Surfaces ◽

Metal Layers ◽

Conductive Surfaces

The Scanning Tunneling Microscope (STM) offers exciting new ways of imaging surfaces of biological or organic materials with resolution to the sub-molecular scale. Rigid, conductive surfaces can readily be imaged with the STM with atomic resolution. Unfortunately, organic surfaces are neither sufficiently conductive or rigid enough to be examined directly with the STM. At present, nonconductive surfaces can be examined in two ways: 1) Using the AFM, which measures the deflection of a weak spring as it is dragged across the surface, or 2) coating or replicating non-conductive surfaces with metal layers so as to make them conductive, then imaging with the STM. However, we have found that the conventional freeze-fracture technique, while extremely useful for imaging bulk organic materials with STM, must be modified considerably for optimal use in the STM.

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Stabilizing pyritic material

The Paleontological Society Special Publications ◽

10.1017/s2475262200005207 ◽

1989 ◽

Vol 4 ◽

pp. 244-248 ◽

Cited By ~ 2

Author(s):

Donald L. Wolberg

Keyword(s):

Significant Contribution ◽

Organic Materials ◽

Sedimentary Rocks ◽

Iron Sulfides ◽

Decomposition Products ◽

Iron Minerals ◽

Pyrite Formation ◽

Organic Sediments ◽

Freshwater Environments

The minerals pyrite and marcasite (broadly termed pyritic minerals) are iron sulfides that are common if not ubiquitous in sedimentary rocks, especially in association with organic materials (Berner, 1970). In most marine sedimentary associations, pyrite and marcasite are associated with organic sediments rich in dissolved sulfate and iron minerals. Because of the rapid consumption of sulfate in freshwater environments, however, pyrite formation is more restricted in nonmarine sediments (Berner, 1983). The origin of the sulfur in nonmarine environments must lie within pre-existing rocks or volcanic detritus; a relatively small, but significant contribution may derive from plant and animal decomposition products.

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A Cognitive-Linguistic Intervention Program: Basic Concept Formation Level

Language Speech and Hearing Services in Schools ◽

10.1044/0161-1461.0801.23 ◽

1977 ◽

Vol 8 (1) ◽

pp. 23-32

Author(s):

Gerald E. Chappell

Keyword(s):

Basic Concept ◽

Concept Formation ◽

Intervention Program ◽

Cognitive Linguistic ◽

Basic Concepts ◽

Linguistic Skills ◽

Linguistic Intervention

Test-teach questioning is a strategy that can be used to help children develop basic concepts. It fosters the use of multisensory exploration and discovery in learning which leads to the development of cognitive-linguistic skills. This article outlines some of the theoretical bases for this approach and indicates possibilities for their applications in child-clinician transactions.

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Prekindergarteners' Performance on The Boehm Test of Basic Concepts

NSSLHA Journal ◽

10.1044/nsshla_16_137 ◽

1988 ◽

Vol 16 ◽

pp. 137-141 ◽

Cited By ~ 1

Author(s):

Amelia Ouellette ◽

Robert Casteel

Keyword(s):

Basic Concepts

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The Developing Relationship Among Cognition, Amplification, and Aural Rehabilitation

Perspectives of the ASHA Special Interest Groups ◽

10.1044/persp1.sig6.46 ◽

2016 ◽

Vol 1 (6) ◽

pp. 47-54 ◽

Cited By ~ 1

Author(s):

Jeffrey J. DiGiovanni ◽

Travis L. Riffle

Keyword(s):

Working Memory ◽

Best Practices ◽

Cognitive Abilities ◽

Hearing Aid ◽

Hearing Aid Fitting ◽

Aural Rehabilitation ◽

Basic Concepts ◽

And Function

The search for best practices in hearing aid fittings and aural rehabilitation has generally used the audiogram and function stemming from peripheral sensitivity. In recent years, however, we have learned that individuals respond differently to various hearing aid and aural rehabilitation techniques based on cognitive abilities. In this paper, we review basic concepts of working memory and the literature driving our knowledge in newer concepts of hearing aid fitting and aural rehabilitation.

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