The stimulative effect of trace elements on seed germination and seedling growth of Pinus tabulaeformis was tested. The experiments were carried out on seed soak and topdressing with different trace elements and varie...The stimulative effect of trace elements on seed germination and seedling growth of Pinus tabulaeformis was tested. The experiments were carried out on seed soak and topdressing with different trace elements and varied concentrations at the nursery of Gardens Research Institute, Harbin, in 2000-2001. The experimental results showed that soaking seed with 1% and 0.2% concentrations of Mn element produced best result for seed germination, and the germination rate was increased by 9%~19% for the seeds treated with 1% concentration and 12%~14% for the seeds treated with 0.2% concentration compared with the control group. The seeds treated with boron element had lowest germination rate. For trace element topdressing, Mn and Mo elements presented good result for seedling growth and the treatment with low concentration was even better. The height or chlorophyll content of the seedlings with spray of low-concentration Mn and Mo element was much higher than that of untreated ones. In the contrast to the treating method of seed soak, topdressing (application of spraying on foliage) had evident effect on seedling growth.展开更多
A new method using high water content material to mechanically fill cross roadways to form artificial bottom for coal faces was introduced. The reasonable determination of filling range, the optimization of the compou...A new method using high water content material to mechanically fill cross roadways to form artificial bottom for coal faces was introduced. The reasonable determination of filling range, the optimization of the compounding ratio of high water content material, and the filling technique were discussed in detail. This new method has been spread after industrial testing in Baodian Colliery. Compared with the traditional method, the manual wooden chock method, the new one decreases about 40% of the filling range and cost in dealing every one set of cross roadway in the testing condition.展开更多
A study was conducted in central Ethiopian highland in 2008 to investigate the consumption of house construction wood, the tree species preference for construction wood and the forthcoming conditions of this forest pr...A study was conducted in central Ethiopian highland in 2008 to investigate the consumption of house construction wood, the tree species preference for construction wood and the forthcoming conditions of this forest product and possible strategies for future availability. Twenty-four iron-roofed houses and twenty-eight thatch-roofed houses belonging to thirty-six farm households were investigated for types, volumes and sources of construction wood used. It was found that an average farmhouse with a floor space of 57 m^2 consumed about 13.7 m^3 of wood. Both floor space and wood consumptions vary with house types An average iron-roofed house with floor space of 51.9 m^2 consumed 16.8 m^3 of wood and an average thatch-roofed house with mean floor space of 28.6 m^2 consumed 3.2 m^3 of wood. Family size and floor space were the major factors influencing construction wood consumption. An average living house was composed of woods of 39.3% ,luniperus procera, 5.6% Cupressus lusitanica, 29.2% Eucalyptus globulus and 26% Eucalyptus camaldulensis. The wood volume from the first two species and half that of the third species were obtained from state forest which is currently banned from any construction wood extraction and hence there is a shortage of around 59.5% of woods. We suggest the promotion of various tree planting approaches to increase the wood supply and the use of alternative local materials like soil bricks for house construction.展开更多
Let ：T2k＋1 be the set of trees on 2k＋ 1 vertices with nearly perfect matchings, and let S2k＋2 be the set of trees on 2k ＋ 2 vertices with perfect matchings. The largest Laplacian spectral radii of trees in ：T2k...Let ：T2k＋1 be the set of trees on 2k＋ 1 vertices with nearly perfect matchings, and let S2k＋2 be the set of trees on 2k ＋ 2 vertices with perfect matchings. The largest Laplacian spectral radii of trees in ：T2k＋l and S2k＋2 and the corresponding trees were given by Guo （2003）. In this paper, the authors determine the second to the sixth largest Laplacian spectral radii among all trees in T2k＋1 and give the corresponding trees.展开更多
文摘The stimulative effect of trace elements on seed germination and seedling growth of Pinus tabulaeformis was tested. The experiments were carried out on seed soak and topdressing with different trace elements and varied concentrations at the nursery of Gardens Research Institute, Harbin, in 2000-2001. The experimental results showed that soaking seed with 1% and 0.2% concentrations of Mn element produced best result for seed germination, and the germination rate was increased by 9%~19% for the seeds treated with 1% concentration and 12%~14% for the seeds treated with 0.2% concentration compared with the control group. The seeds treated with boron element had lowest germination rate. For trace element topdressing, Mn and Mo elements presented good result for seedling growth and the treatment with low concentration was even better. The height or chlorophyll content of the seedlings with spray of low-concentration Mn and Mo element was much higher than that of untreated ones. In the contrast to the treating method of seed soak, topdressing (application of spraying on foliage) had evident effect on seedling growth.
文摘A new method using high water content material to mechanically fill cross roadways to form artificial bottom for coal faces was introduced. The reasonable determination of filling range, the optimization of the compounding ratio of high water content material, and the filling technique were discussed in detail. This new method has been spread after industrial testing in Baodian Colliery. Compared with the traditional method, the manual wooden chock method, the new one decreases about 40% of the filling range and cost in dealing every one set of cross roadway in the testing condition.
基金the Austrian Exchange Service for financially supporting this study as part of the academic thesis of the first author
文摘A study was conducted in central Ethiopian highland in 2008 to investigate the consumption of house construction wood, the tree species preference for construction wood and the forthcoming conditions of this forest product and possible strategies for future availability. Twenty-four iron-roofed houses and twenty-eight thatch-roofed houses belonging to thirty-six farm households were investigated for types, volumes and sources of construction wood used. It was found that an average farmhouse with a floor space of 57 m^2 consumed about 13.7 m^3 of wood. Both floor space and wood consumptions vary with house types An average iron-roofed house with floor space of 51.9 m^2 consumed 16.8 m^3 of wood and an average thatch-roofed house with mean floor space of 28.6 m^2 consumed 3.2 m^3 of wood. Family size and floor space were the major factors influencing construction wood consumption. An average living house was composed of woods of 39.3% ,luniperus procera, 5.6% Cupressus lusitanica, 29.2% Eucalyptus globulus and 26% Eucalyptus camaldulensis. The wood volume from the first two species and half that of the third species were obtained from state forest which is currently banned from any construction wood extraction and hence there is a shortage of around 59.5% of woods. We suggest the promotion of various tree planting approaches to increase the wood supply and the use of alternative local materials like soil bricks for house construction.
基金supported by the National Natural Science Foundation of China under Grant No. 10331020.
文摘Let ：T2k＋1 be the set of trees on 2k＋ 1 vertices with nearly perfect matchings, and let S2k＋2 be the set of trees on 2k ＋ 2 vertices with perfect matchings. The largest Laplacian spectral radii of trees in ：T2k＋l and S2k＋2 and the corresponding trees were given by Guo （2003）. In this paper, the authors determine the second to the sixth largest Laplacian spectral radii among all trees in T2k＋1 and give the corresponding trees.
