Browsing University of Hertfordshire by Issue Date
Now showing items 1-20 of 24755
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The Revolution in Tanner's Lane
(1971) -
Fabrication of single-crystal semiconductor optical waveguides by solid-state diffusion
(1972)Optical surface waveguides have been fabricated by diffusing selenium into single-crystal CdS substrates to produce graded-composition CdS Se crystals. Planar guides which confine a beam in one dimension and guides produced ... -
Fluorescence of graded-band-gap CdSxSe1-x crystals produced by diffusion
(1972)The fluorescence of CdSxSe1-x mixed crystals with band-gap gradients as large as 1200 eV/cm has been investigated at 77°K. The graded samples were produced by heating CdSe or CdSxSe1-x platelets in a sulfur-selenium ... -
Optical waveguides by diffusion in II-VI compounds
(1972)Planar optical waveguides have been made by sealed ampoule diffusion of Cd and Se into ZnS and Cd into ZnSe. Three-dimensional diffused guides of Cd-diffused ZnSe have been made by using a masking layer of evaporated ... -
Infection of protoplasts from yeast with tobacco mosaic virus
(1972-12-22)PROTOPLASTS from higher plant cells can become infected with plant viruses under special conditions, and it has been shown that yeast cells can become infected with viruses normally found in different fungal genera . We ... -
Waveguide electro-optic modulation in II-VI compounds
(1973)Electro-optic intensity modulation is demonstrated in three-dimensional (channel) waveguides fabricated by diffusion techniques in ZnSe and CdS. Typical diffused guide dimensions are 1.6 μm × 19 μm × 2 mm. Two electrode ... -
Photoluminescence determinations of Cd diffusion in ZnSe
(1973)The diffusion constant D(T) of cadmium into single-crystal zinc selenide was measured using a photoluminescence/etch technique. Diffusions were performed in sealed ampoules using cadmium metal and cadmium selenide powder ... -
A technique for obtaining the electrocardiogram of fish
(1973-02-01)1. A method is described which enables the electrocardiogram of a fish to be studied over extended periods using chronically implanted electrodes. 2.2. This method has been used successfully for studies on restrained and ... -
Lawrence, Leavis and culture
(1974) -
The explanatory power of Chomsky's transformational generative grammar
(1974)One of the main difficulties in Chomsky's account of generative grammars and linguistic theories is to determine what exactly these grammars and theories explain. In some places Chomsky seems to be saying that they explain ... -
Additives for the enhancement of fusion and endocytosis in higher plant protoplasts : An electrophoretic study
(1974-06-01)A range of additives has been employed to enhance both endocytosis and fusion in isolated higher plant protoplast systems. The effects of these compounds, at various concentrations, on the electrical properties of the ... -
Refractive index profile measurements of diffused optical waveguides
(1974-09-01)Refractive index profiles resulting from the fabrication of optical waveguides by diffusion techniques are measured using a reflection interferometric technique. In Cd-diffused ZnSe waveguides, the index variations are ... -
Behavioural effects of electrical stimulation of the hypothalamus of the goldfish (Carassius auratus)
(1975)Food-satiated goldfish were stimulated in tanks containing food on the surface of the water and on the bottom of the tank. Various components of the feeding response were seen, and complete feeding was observed, which was ... -
A new waveguide switch/modulator for integrated optics
(1975)A waveguide optical switch and/or modulator device is described that uses a single-mode waveguide version of the Mach-Zehnder interferometer. A mode selective branching waveguide is used for switching, and modulation can ... -
Early stages in cell wall regeneration of tobacco mesophyll protoplasts : An electrophoretic study
(1975-02-01)The electrophoretic mobilities of isolated mesophyll protoplasts of Nicotiana tabacum var. Xanthi n.c. were measured using a whole cell electrophoresis apparatus. Changes in mobility were recorded at times during aseptic ... -
The isolation and culture of cucumber mesophyll protoplasts
(1975-03-01)Large numbers of viable protoplasts were obtained from the first leaves of two cultivars of cucumber, Cucumis sativus L. cv. Ashley and China. Cell wall regeneration was observed in liquid culture within 3 days of isolation, ... -
Ribosomal RNA metabolism in cucumber leaf mesophyll protoplasts
(1975-07-01)Aspects of the metabolism of RNA have been studied in enzymatically isolated protoplasts from cotyledon and first leaf mesophyll tissue of two cultivars of cucumber. The first leaf mesophyll protoplasts incorporated ( ... -
Refractive index profile optimization in diffused graded index lenses
(1975-10)Refractive index profiles resulting from simple diffusion processes in glass are calculated, and optimum choices of diffusion parameters are chosen from minimum error in approximating focusing refractive index profiles. ... -
Preliminary studies on the RNA components of three strains of cucumber mosaic virus
(1975-11)In investigations of the causal relationships between disease symptoms and virus infection of plants, three strains of cucumber mosaic virus (viz. N, Price's No. 6 and W) which caused different symptoms in several plant ...