Attraction of Fish to Mercury Vapour Light and Its Application in a Generating Station Forebay

Laboratory and field tests were conducted to determine the effectiveness of filtered mercury vapour lights in attracting fish with possible utilization in a fish conserving scheme at an electrical generating station. In laboratory tests, alewife demonstrated an attraction to the mercury vapour light which was associated with an increase in swimming activity. This response was maintained over a 48-hour period. When the filtered mercury vapour lights were utilized in association with a fish pump in the Nanticoke Generating Station forebay, juvenile gizzard shad and smelt were attracted to the pump area. Although there was variation with time of day, tubidity and lighting array; the results suggested that the number of fish passing through the pump increased when the mercury vapour lights alone or when the mercury lights in association with a white strobe light were employed.     

The Diffusion of Carbon Dioxide and Water Vapour through Stomata

An account is given of the diffusion of carbon dioxide and ofwater vapour through the stomata of leaves in the presence ofair. It shows that the argument given in K. J. Parkinson andH. L. Penman's paper (1970): ‘A Possible Source of Errorin the Estimation of Stomatal Resistance’ is substantiallyincorrect. However, the correction factors to the sugar beetdata presented in their paper are valid owing to a fortuitousset of circumstances including the similarity in magnitude oftwo mutual diffusion coefficients. The concept of stomatal resistanceis criticized.     

压电石英晶体免疫传感器

近年来压电石英晶体免疫传感器作为一种新型生物传感器发展迅速,该文对其检测原理、材料选择、振荡模式选择及再生使用进行了详细介绍,并介绍了其在微生物检测、病毒和蛋白质检测,环境监测方面的具体应用。     

Water Vapour Calibration using Salt Hydrate Transitions

There is a thermodynamic equilibrium between hydrate pairs ofa salt and the water vapour pressure of the surrounding gas.The vapour pressure depends on the nature of the salt hydratepair and on the salt temperature. It is shown that the transitionof ferrous sulphate from the heptahydrate to the tetrahydratewill humidify flowing gas to this equilibrium vapour pressure,provided that the gas is in contact with the crystals for about12 s. The relationship between the equilibrium water vapourpressure and crystal temperature has been established over therange 10–40 ?C (with an accuracy of ?0-1 ?C at 16 ?C).At 20 ?C the equilibrium relative humidity is 55.8%. A practical humidity calibrator based on this hydrate transitionhas been built and tested. Using two-way valves, the input supplyof dry air is divided so that part goes to the exit directly,and the rest to the exit via a ferrous sulphate column maintainedat a constant and measured temperature. By varying the fractionpassing through the ferrous sulphate, the humidity of the emergentair may be varied between zero and the humidity in equilibriumwith the ferrous sulphate.     

Vapour action of fungicides against powdery mildews

Certain fungicides prevented the growth of powdery mildews at distances extending several millimetres beyond the edge of localized deposits on leaves. Most of the materials also acted at a distance when separated from the leaf by glass cover-slips, indicating that the effect was due to the emission of vapour. In addition to sulphur and lime-sulphur, whose vapour action is already known, fungicides based on drazoxolon, oxythioquinox, binap-acryl, dinitro-octyl phenyl crotonates and a phthalimido-phosphonothionate were found to act in this way. Two systemic fungicides, griseofulvin and triamiphos, did not give a detectable vapour action. Tests were conducted mostly on open glasshouse benches. A draught from a fan shifted the zones of inhibition to one side of the deposits, but did not reduce their areas. Vapour effects were similar in extent on plants maintained at 18–25° C and at 27–32° C. Variation in the areas protected was studied in relation to the size and fungicide content of the deposits, to different powdery mildews, to time of incubation and to different types of formulation. Deposits applied to leaves by high- or low-volume sprays at concentrations used in the field gave significant protection at a distance. Vapour effects were demonstrated also on mildew conidia incubated on glass slides bearing a spot of fungicide, and on infected plants placed in beakers coated on the bottom with fungicide. Movement of fungicides in the gaseous state is discussed in relation to the control of foliage diseases in the field.     

Water Vapour and Heat Transfer in Leaves

Factors connected with the formation of water droplets in leavesby distillation from the mesophyll to the epidermis were investigatedin a number of species. It was concluded that in illuminatedleaves water droplets form principally on the inner walls ofguard and subsidiary cells, and sometimes below the anticlinalwalls of epidermal cells, because these sites are cooler thanthe rest of the leaf. Under more isothermal conditions any waterdroplets that had formed disappeared. With increasing waterstress water droplets did not form so readily, though distillationwas occurring. Few water droplets were observed in leaves outof doors that had open stomata. Significant temperature gradientswere measured across leaves with thermocouples, but these werelarger than were gradients calculated from measured thermalconductivities of leaves. The evaporation resistances of theinner walls of the epidermis and of the mesophyll were foundto be similar. This led to the conclusion that the hydrophobicityof the surfaces of these tissues is similar. Water transferin leaves in the vapour phase was found to be more responsiveto temperature than to water stress gradients. leaf, evaporation, distillation, heat loss, transpiration     

Sterilization by Means of Hydrochloric Acid Vapour

As heat sterilization of glass bottles often results in breakage and of most plastic containers in deformation, we investigated a rapid low-temperature sterilization method as an alternative. Vapour evolving from hydrochloric acid was chosen because it does not leave toxic residues which might contaminate food packed in treated containers. Vapour evolving from 0.25 ml of 31% (w/w) hydrochloric acid reduced the number of viable spores of aerobic and anaerobic bacteria in bottles (300 ml) by a factor of at least 2500 and that from 0.01 ml of 37% (w/w) hydrochloric acid reduced the number of mould spores by a factor of over 40 000 within 5 min at 20°C.     

Water Vapour Diffusion in the Substomatal Cavity

In this paper stomatal pore and substomatal cavity are considered to be elliptic cylinders, A three-dimensional diffusion model is presented, which describes the diffusion of vapour from the surfaces of the cells surrounding the cavity to the outer end of the pore Equations describing vapour diffusion in the model are set up, based on Fick's law and the law of conservation of mass, and are solved by using computer. Quantitative relation between the cavity resistance to water vapour diffusion and: stomatal aperture is obtained and is given more general theoretical explanation. Comparing the formula obtained in this paper with those of Brown and Escombe and of Cooke et al., it is found that the cavity resistance calculated by the latter two formulas are 0.5 to 1 times higher in a large rankle of stomatal aperture values. Besides, it is shown by calculating that the rates of loss from guard cells and subsidiary ceils account for 88%– 93% and 7%–12% respectively of that from epidermic cells, and the litter amounts to 86%–96% of that from all the cells in the cavity in the large range of stomatal change.     

The Importance of Water Vapour for the Circulating Air Flow through Nelumbo nucifera

Aquatic vascular plants depend on an adequate oxygen supplyin order to maintain growth and reproduction in anaerobic environments.Nelumbo nucifera is able to survive with a gas transport systemwhich supplies oxygen to the roots and rhizomes submerged inthe anaerobic sediment. It was possible to demonstrate thatthis gas transport system is based on a purely physical phenomenonThermo-osmotic oxygen transport was first demonstrated on freshleaves with the help of an oxygen-sensitive electrode. A definiteenhancement of oxygen flow was obtained through excised leaveswhen a temperature difference between the ambient and lacunarair was present in light. These leaves were then dried to brittlenessand the enhanced oxygen flow was still detectable. This showsthat not only photosynthetic oxygen, but also atmospheric oxygencan be transported to the buried organs. The absolute flow ofoxygen through dry leaves was much lower than through freshleaves, but the thermo-osmotic transport of oxygen still functioned.Furthermore, the process of thermo-osmosis need not rely ona difference in humidity between the two sides of a porous partition,but may be linked causally to the temperature difference andthe pore size. Key words: Nelumbo nucifera, oxygen transport, thermo-osmosis of gases