Sharp Junction Research Articles

AN ASSESSMENT OF THE RELATIONSHIP BETWEEN THE SURFACE PROPERTIES OF CHALK SOILS AND SLOPE FORM USING PRINCIPAL COMPONENTS ANALYSIS

SummaryFive line transects were sited over grass‐covered, convex‐concave slopes in the Berkshire and Wiltshire chalk downs, with the object of describing and interpreting the variation in selected surface soil properties. Previous work had concentrated upon the correlation between single variables and slope gradient and slope length, whereas the emphasis of the present paper lies in examining the interrelationships amongst the variables through the use of principal components analysis.A consistent pattern of variation was established between the five sites. The first component derived from the analysis was interpreted as a combined organic matter and soluble constituents factor, which accounted for between 50 and 60 per cent of the total variance. The second component was identified as particle‐size variation and accounted for a further 13 to 18 per cent of the total variance.Whereas the distribution of the component scores for the second component supported the original idea of a sharp junction effect in the pattern of soil properties on the slope, the first and most important component indicated a more diffuse transition from net erosion to net deposition conditions.

Two types of squamous epithelium of the human ectocervix. A histological and colposcopic study.

Summary:The human ectocervix is divided into two zones, a circumoral regenerate epithelium and a more peripheral native epithelium. Each zone possesses a specific histological and colposcopic structure involving epithelial and subepithelial layers. Colposcopic examination reveals a difference in colour and texture of the two areas, whilst histological examination reveals differences in the type and arrangements of cells and tissues in both epithelial and subepithelial layers. These differences are manifest at a sharp junction represented by the line visible in the colposcope.The significance of the occurrence of atypical epithelia on the more central (regenerate) portion of the cervix as it affects the problem of the origin of cancerous change is discussed. A homology is suggested concerning the sharp junction always found between native and regenerate epithelia and a similar junction sometimes found between atypical and native epithelium.

Epitaxial Growth of Silicon by Vacuum Evaporation

SINGLE crystal layers of silicon up to 50µ thick have been deposited on to a heated single crystal silicon substrate. Reflexion electron diffraction of the deposited layer showed Kikuchi lines indicating a high order of crystalline perfection. PN junctions with a maximum reverse breakdown of voltage in excess of 300 V. have been made. The conventional bevelling and staining techniques1 showed a sharp junction between the deposited layer and the substrate. Maximum resistivities of 10 Ω-cm. for P-type and 3 Ω-cm. for N-type layers have been obtained.

A Study of Two Directions of Folding: The Structural Geology of the Monadhliath and Mid-Strathspey

A review of the different ways in which more than one direction of folding has been thought to occur in one area and a classification of the different varieties of cross folding described in the literature are given. An area of complex folding in Moine metasediments is described. Consideration of the style of folding and the orientation of axial planes supports the view that an initial phase of homoaxial folding developed about axes plunging southeastward. This folding was accompanied by slide tectonics repeating the succession in large tectonic inclusions. The deformation was monoclinic and apparently in response to a regional sinistral movement (looking northward along the fold axes). A second phase of folding turned the folds of half the area through about 48°, producing a dominant southwesterly trend and a sharp junction line with crossing (mainly east-west) structures at the boundary between the originally disposed and the rotated block. Dislocation of the line of junction proves the magnitude of the...

VII.—Note on a Section in Probable Bagshot Beds on Shooters Hill, Kent

In 1905 trenches for electric mains were carried up the northeastern slope of Shooters Hill, along Shrewsbury Lane to “The Bull”, and thence down the western hill-slope along the Dover Road. From about 350 O.D. in Plum Lane to 424 O.D. at “The Bull” the trench ran for nearly two-thirds of a mile along the junction of the London Clay with the overlying group of sands, pebbles, and clayey gravels which form the ‘gravel cap’ of Shooters Hill. Neither the exact age of these superficial deposits nor their mode of formation—whether marine or fluviatile beds—is as yet known, but the general coarseness of the sands, the presence of pebbles of Lower Greensand chert, and the very stiff clayey matrix of the gravel distinguish them from typical Bagshot Beds, and moreover throughout the greater part of the section a sharp and irregular junction could be traced between them and the brown London Clay. At a few points, however, the top of the London Clay was seen to pass into pale-brown and yellowish sandy clays, sometimes of significant thickness. Thus in the Dover Road, about 100 yards above Christ Church, below the thick red clayey gravel of the ‘cap’, lay about 3 feet of yellow loam, the lower part of which became a pale-brown clay passing quite gradually into normal blue or brown London Clay with septarian nodules. In the same series of excavations (1905) a trench at the junction of Shrewsbury Lane with the Dover Road showed the Shooters Hill gravel resting irregularly on a bed of fine clean yellowish sand quite unlike anything previously noted in the numerous pits and trenches opened upon the Hill, but as unfortunately the trench was only a few feet deep the relation of this fine sand to the London Clay could not then be made out.