Enhancement of contrast in living and fixed specimens by the use of fibre optics
A method is described which enhances the contrast of living and fixed specimens examined with the stereomicroscope. It consists of immersing the ends of flexible fibre optic light sources together with the specimen in the fluid used for examination. It is reported that not only does this method increase the contrast of living specimens but that it may also be applied to specimens being prepared as thin sections or freeze fracture surfaces for examination with the transmission electron microscope. A further method of enhancement of contrast is suggested which involves the fitting of light filters of complementary colours, one to each of the fibre optic light sources, before immersion with the specimen.
Contrast Methods in Microscopy: Rheinberg Illumination
In 1896, Julius Rheinberg introduced a color contrast method to the microscopy world. This method uses colored discs relatively near the back focal planes of the objective, or more commonly, near the aperture focal plane of the condenser to provide a colored specimen on a colored background. Almost any microscope can be modified to generate this style of imaging, which can be accomplished using a few practical options. The Rheinberg technique is a modification of the darkfield (or darkground) method of illumination and the color contrast enhances the visibility of specimens and their texture. It also provides an esthetically pleasing view of specimens worthy of photomicrography awards.
Centrifuge modelling of effects of shield tunnels on existing tunnels in soft clay
With the rapid development of the subway network,the phenomena of shield tunnels going across the adjacent tunnels are becoming more and more common.The interaction between shield tunneling and nearby tunnels is more complicated than the ordinary shield tunneling in intact soil strata.Based on the project of Shanghai Bund Passage crossing Metro Line 2,the method of centrifuge modeling together with the field measurement is employed to study the effects shield tunneling on nearby strata and existing tunnels.In centrifugal model tests,the effects simulation techniques considering the unloading of excavation,ground loss and grouting are developed to analyze the longitudinal settlement of the shield tunnel and the existing tunnel induced by the shield tunneling.Besides,the deformation distribution and settlement curves of the existing tunnels during shield construction are studied by using the monitoring data.