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1.
《Wood material science & engineering》2013,8(4):186-195
Abstract This work was an investigation of the effect of nanoparticles on the durability of wood specimens exposed to artificial weathering. TiO2 and clay nanoparticles were mixed with preservative (Wolmanit CX-8) for improving the durability of Norway spruce (Picea abies). Impregnated and untreated specimens were subjected to Atlas Solar Simulator accelerated ageing test chamber for solar radiation and water spray exposure. The effectiveness of the treatment against colour and chemical changes was investigated using CIEL*a*b* colour measurements system and Fourier transform infrared analysis. The present study showed that the wood specimens that had been treated with preservatives containing nanoparticles were slightly more stable against artificial ageing than both untreated specimens and specimens treated with preservative alone. 相似文献
2.
A series of experiments were conducted in which label rate (0.3 g per kg of wheat) with diatomaceous earth (DE) formulation
Protect-It. Exposure studies were carried out at two levels of relative humiditiy (40% and 55%), two levels of insect density
(10 or 20 adults per vial), and three levels of exposure periods. Test insects were placed in vials containing 40 g of soft
white winter wheat mixed with either 0 or 0.3 g Protect-It per kg of wheat. After relating exposure periods for both insect
density and relative humidity levels, highest mortality was only 16%. Mortality, regardless of the dose rate applied (0 and
0.3 g) were not significantly increased as the exposure period increased. Regardless of relative humidity (r.h.) (40% and
55%r.h.), mortality in control were not significantly increased as the exposure period increased for the same insect density.
However, significant differences among the three exposure periods in 10 adults’ density in 0.3 g DE application. Mortality
was significantly increased in 10 adults’ density. In this case mortality of R. dominica adults increased with the increasing of the exposure intervals. As for 20 adults’ density, mortality in 0.3 g DE application
was not significantly changed along with the exposure intervals. After insects were exposed for 1, 2, or 3 week, dead and
live insects were removed, and the wheat in the vial were returned to relating humidity box and kept for 8 week until F1 adults emerged. Then, the number of F1 adult was counted. The mean numbers of F1 adults on untreated wheat at all density and r.h. combinations, regardless of exposure periods were significantly higher
than that of 0.3 g DE- treated wheat (Fig. 3). At each density and treatment, the mean number of F1 adults at 55% r.h. were higher that that of 40%r.h. The comparison between adult densities at each r.h. and treatment showed
that adult densities influenced the F1 production of R. dominica and F1 adults were always higher at 20 adults’ density. The mean number of F1 adults at each density, regardless of treatment progressively increased as the exposure period increased. Fewer progeny were
produced at 10 adults’ density compared to 20 adults’ density for same exposure periods. The highest reproduction occurred
in 3 week of exposure period for both insect densities. Regardless of adult densities, the mean number of F1 adults was significantly increased as the exposure period increased (Fig. 5) for both control and 0.3 g DE treatment. Reduction of F1 adults at 0.3 g DE application compared to control were found to be 76.88, 74.78 and 67.63% for 1, 2 and 3 week of exposure
period, respectively. 相似文献
3.
Basic structure and algorithm of leaf mechanism photosynthesis model were described in first part of this study based on former
researcher results. Then, considering some environmental factors influencing on leaf photosynthesis, three numerical sensitivity
experiments were carried out. We simulated the single leaf net CO2 assimilation, which acts as a function of different light, carbon dioxide and temperature conditions. The relationships between
leaf net photosynthetic rate of C3 and C4 plant with CO2 concentration intercellular, leaf temperature, and photosynthetic active radiation (PAR) were presented, respectively. The
results show the numerical experiment may indicate the main characteristic of plant photosynthesis in C3 and C4 plant, and further can be used to integrate with the regional climate model and act as land surface process scheme, and better
understand the interaction between vegetation and atmosphere.
Foundation Item: This paper was supported by Natural Science Foundation of China (Grant No. 39900084)
Biography: ZHANG Jia-hua (1966-), male, Ph. Doctor, Associate professor in START, Institute of Atmospheric Physics. Chinese Academy
of SciencesBeijing, 100029, P. R. China
Responsible editor: Chai Ruihai 相似文献
4.
Acacia melanoxylon, a N2-fixing timber tree occurring naturally in eastern Australia, is now promoted as a component of silvopastoral systems; but the interaction of the tree with pasture and soils has not been adequately studied. This study investigated the effects of Acacia melanoxylon on soil nitrogen (N) levels, N availability, soil pH, bulk density, organic carbon, C:N ratios and soil moisture in three separate silvopastoral sites with contrasting soil types in the North Island of New Zealand. At each site four tree stocking rates were studied (0, 500, 800, and 1700 stems ha–1). The trees were nine years old at the time of the study. Soil samples from each study site were taken once at three depths (0 to 75 mm, 75 to 150 mm, and 150 to 300 mm), with three replicates per tree stocking rate. Soil analyses showed that although there were differences between soil types, few statistically significant differences occurred due to tree stocking rate. A greenhouse pot trial growing ryegrass (Lolium multiflorum L. cv. Concord) in soil from the A horizon of each soil type from under the trees and the open pasture found that ryegrass yield, N uptake and N supply increased with increasing tree stocking rate. Increased N supply under the trees, coupled with greater soil moisture compared to the open pasture may have accounted for the higher pasture yield under Acacia melanoxylon compared to non dinitrogen fixing tree species. This study suggested that Acacia melanoxylon in a silvopastoral system had the potential to increase soil N availability.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
5.
Sylvie Carles Delphine Boyer Groulx Mohammed S. Lamhamedi André Rainville Jean Beaulieu Pierre Bernier 《Journal of Sustainable Forestry》2013,32(3):169-198
Tree improvement programs aim to develop families that are well-adapted to future growing conditions. To gain insight into the stability of the family genetic response to climate change, white spruce (Picea glauca) seedlings from 60 full-sib families were subjected to a combination of two temperature regimes and two levels of CO2 over two growing seasons. There was positive effect of warmer temperatures and higher CO2 on some growth variables but no significant family × treatment interactions. Instantaneous water use efficiency was the only physiological trait that was affected positively by the CO2 treatment, showing a 51% increase that was consistent across families. 相似文献