Library

Notes: The characteristic properties of noncritically phase-matched frequency doubling in KTiOPO4 have been investigated using ∼1 μm radiation from a Styryl-13 dye laser. Noncritically phase-matched type II second-harmonic generation was found to occur at 994.3 nm. The unusually wide angle, temperature, and wavelength tolerances observed for this nonlinear process are attractive for the design of practical blue-green laser sources. A special strained-layer InGaAs diode laser was fabricated to operate at 994 nm and generation of blue-green 497 nm radiation by noncritically phase-matched frequency doubling was demonstrated.

Notes: Thin films of hydrogenated amorphous carbon (a-C:H) have been evaluated as quarter-wave, antireflection dielectric coatings for application in magneto-optic data storage media. The films, which are produced by plasma deposition from methane, have low optical absorption at 830 nm wavelength, high refractive index (n≈2.1), and provide enhancement of the polar Kerr rotation (θk) when used in conjunction with rare-earth–transition-metal (RE–TM), TbFe, or TbFeCo alloys. The chemical stability, inertness, and homogeneity of the carbon films makes them effective diffusion barriers to oxygen or water vapor and thus provides excellent protection against environmental oxidation of the RE–TM layer. Dynamic disk performance data show improved write sensitivity of the media when used with a-C:H dielectric layers.

Notes: This paper is based on a critical review of the proceedings of the Second International Conference on Interdisciplinary Research held in 1981 in Manchester, England. Two sets of issues important for the management of collaborative research are identified. One is the need to remove ambiguities from the meanings of commonly used terminology, for which more precise definitions are proposed. Cross-disciplinary is used to describe only the nature of the task; multi- and inter-disciplinary are seen as describing alternative organizational ways of executing it. Which way should be used depends objectively on the circumstances.The other set of issues is concerned with the effect institutional setting could have on the possibility of carrying out effective cross-disciplinary activity. Six different settings are identified and broad concepts of group dynamics are used to identify theoretical and practical problems and their possible solutions. The paper concludes with a survey of the practical implications for those managing cross-disciplinary research.

Notes: [Auszug] IN a recent communication from this Laboratory1, it was shown that unstable heavy nuclei are sometimes emitted during the explosive disintegrations produced in photographic plates by the passage of cosmic radiation. In some cases., these unstable particles, after being brought to rest in the ...

Notes: Abstract Strings of moored sediment traps were deployed in a 150 m water column over a period covering the growth and collapse of the spring bloom (4 April–3 June 1976) in an area of the northern North Sea. The efficiency of collection of material in the moored traps was compared to collections in free-drifting traps in the same area of deployment. The ways in which the data from the trap collections may be interpreted was considered at some length and a best estimate of the flux of organic carbon and nitrogen to the sediment was made. For the period prior to the spring bloom (4–23 April) this flux was 50 mg C m−2 d−1 (about 20% of primary production). During the bloom (24 April–19 May) it was about 185 mg C m−2 d−1 (35% of production) and during early summer (20 May–3 June) it was 115 mg C m−2 d−1, about 25% of the overlying production. The organic carbon and nitrogen content of the material collected was measured and the material was examined microscopically. There was evidence of a large settlement of diatoms immediately after the spring bloom which was reflected in changes in the C:N and C:chlorophyll ratios of the material collected. This change in biochemical composition of the material may affect its nutritional quality and have a stimulatory effect on the growth and reproduction of the animals living in the sediment.

Notes: Summary These supporting concepts enable us to much more adequately understand the meaning of apoha. First, a sharp distinction is drawn between the real and the conceptual; the real is particular, unique, momentary and the basis of perception, while the conceptual is universal, general, only supposedly objective and the basis of language. Second, the complex nature of negation discloses the kind of negation meant by apoha. Negation by implication is seen as disclosing the necessary relation between simple affirmations and simple negations. It is in this sense that Dignaga asserts that the meaning of words lies in the negation of the opposite. Third, the idea of apoha as the differentiation of concepts is to be distinguished from the Nyāya-Vaiśe $$\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle\cdot}$}}{s}$$ ika notion of exclusion as a materially present quality in objects. Ratnakirti, and Mok $$\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle\cdot}$}}{s}$$ ākaragupta following him, use the idea of negation by implication to explain apoha as the simultaneity of and logical relation between a positive assertion concerning an epistemological object and a negative assertion concerning all things which are not that epistemological object. For example, Ratnakirti in accordance with the theory of apoha explains that the term cow “harbors” the negation of non-cow in the same way that blue is harbored in the term blue lotus. The exclusion of the other, i.e., the negation of the non-cow, is held by Ratnakirti to be an actually apprehended attribute of the cow cognized (as distinct from the cow in itself). He says “... discrimination of non-cow inevitably arises simultaneously with the perception of the cow, for (the negation of non-cow) is the qualifier (of the individual).” This interaction between the positive and the negation of the other, i.e., the relation of negation by implication, as a simultaneous interaction is necessary lest when, e.g., asked to tie up a cow one ties up a horse instead. Mok $$\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle\cdot}$}}{s}$$ ākaragupta denies three possible interpretations of apoha before putting forth his own definition. The first is that when an external object is conceptualized this is done as “the other (the dissimilar) is discriminated from this.”The second is much the same, only it is in terms of the mental image, i.e., the epistemological object rather than the ontological object as in the first. The third is that apoha means the negation of an assertion, i.e., the simple absence of the other. All three of these interpretations are unacceptable to Mok $$\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle\cdot}$}}{s}$$ ākaragupta. He defines apoha as “the affirmation (of a positive entity) qualified by discrimination (of it from all other entities).” Mok $$\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle\cdot}$}}{s}$$ ākaragupta goes on to explain this simultaneity more fully: ... those who stress affirmation think that after we have known the cow, we consequently determine the discrimination of the essence of the cow from that of the non-cow; those who stress the negative function of apoha are of the opinion that we first know the discrimination of the dissimilar thing and then consequently confirm the thing which is discriminated from others, viz., the cow. Thus (both interpretations) are wrong. For at the time of judgment we do not experience an order of comprehension in which (negation or affirmation) occurs first. In fact, it is not the case that one, having understood the affirmation, later confirms the negation by implication, or that one having understood the negation later confirms what is discriminated (from the dissimilar). Therefore, we say that the very understanding of the cow is the same as the understanding of what is discriminated from the dissimilar. We can see from this that for Ratnakirti and Mok $$\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle\cdot}$}}{s}$$ ākaragupta apoha meant the simultaneous affirmation of and negation of the dissimilar from the (epistemological) object. Mok $$\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle\cdot}$}}{s}$$ ākaragupta's concern with the “time of judgment” also shows that the idea of apoha was understood by them as being psychologically descriptive. In the process of identifying an epistemological object as some particular thing, neither the negative nor the positive function have priority but are, rather, complementary one to the other. This simultaneity and complementarity are supported by the examination of mind “at the time of judgment,” i.e., it is a psychological description of the process of identification of an epistemological object as some particular thing. It is this fact of apoha describing the process of identification which, as described above, places apoha in the inference category of sources of truth. Apoha is clearly, therefore, involved with words and concepts rather than being on the perception side where it would have to be a metaphysical concept describing the real or absolute. Putting the idea of apoha into contemporary terms we can say that it is a psychological descriptor for the bipolar relation of concepts. Dignaga and the other Buddhist logicians are then to be understood here as being involved in producing a phenomenological description of linguistic thought processes. More broadly, as in the discussion of perception, they are involved in the phenomenological description of consciousness, a favorite Buddhist undertaking. As such, the work of the Buddhist logicians fits into the larger soteriological intention of all Buddhist thinkers, since enlightenment is understood to follow from insight into the nature of consciousness as productive of suffering. Some authors have criticized the logicians as being overly concerned with the un-Buddhist occupation of arguing. However, when their work is seen as expanding our understanding of the nature and working of consciousness, the logicians are certainly worthy of our respect.

Notes: [Auszug] IT is of interest and importance to know the energy distribution of the radiation emitted from betatrons and synchrotrons, since such knowledge is necessary in cases where cross-sections of nuclear reactions are to be determined1, and in estimating the clinical effect of such radiation. For some ...

Notes: [Auszug] IN the application of the photographic method to research in cosmic-ray and nuclear physics, the need has always been felt for emulsions of thickness comparable with the range of the particles to be recorded. The use of thick emulsions has been greatly restricted, however, by the difficulties ...

Notes: JOURNAL of the ANTHROPOLOGICAL SOCIETY OF LONDON