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排序方式: 共有273条查询结果,搜索用时 15 毫秒
111.
Eguchi N Morii N Ueda T Funada R Takagi K Hiura T Sasa K Koike T 《Tree physiology》2008,28(2):287-295
Water relations in woody species are intimately related to xylem hydraulic properties. High CO(2) concentrations ([CO(2)]) generally decrease transpiration and stomatal conductance (g(s)), but there is little information about the effect of atmospheric [CO(2)] on xylem hydraulic properties. To determine the relationship between water flow and hydraulic structure at high [CO(2)], we investigated responses of sun and shade leaves of 4-year-old saplings of diffuse-porous Betula maximowicziana Regel and ring-porous Quercus mongolica Fisch. ex Ledeb. ssp. crispula (Blume) Menitsky grown on fertile brown forest soil or infertile volcanic ash soil and exposed to 500 micromol CO(2) mol(-1) for 3 years. Regardless of species and soil type, elevated [CO(2)] consistently decreased water flow (i.e., g(s) and leaf-specific hydraulic conductivity) and total vessel area of the petiole in sun leaves; however, it had no effect on these parameters in shade leaves, perhaps because g(s) of shade leaves was already low. Changes in water flow at elevated [CO(2)] were associated with changes in petiole hydraulic properties. 相似文献
112.
Jie Liu Ryo Ando Kuniyoshi Shimizu Koh Hashida Rei Makino Seiji Ohara Ryuichiro Kondo 《Journal of Wood Science》2008,54(1):68-75
In humans, steroid 5α-reductase is involved in the development of benign prostatic hyperplasia (BPH). We tested the steroid
5α-reductase inhibitory activity of the 70% acetone extract of woody plants. The tannin polymer prepared from the 70% acetone
extract showed the highest steroid 5α-reductase inhibitory activity. Furthermore, the steroid 5α-reductase inhibitory activity
of tannins was not affected by the addition of superoxide dismutase or catalase. It was concluded that the steroid 5α-reductase
inhibitory activity of condensed tannin was caused by binding to the steroid 5α-reductase, rather than from the peroxide/superoxide
produced by tannins. The tannins, prepared from tree barks, with potential for steroid 5α-reductase inhibitory activity might
be advantageous in therapy for steroid 5α-reductase diseases such as BPH or prostate cancer.
Part of this report was presented at the 54th Annual Meeting of the Japan Wood Research Society, Sapporo, August 2004 相似文献
113.
114.
Kazuyuki Hattori Sota Shikata Ryo Maekawa Masakazu Aoyama 《Journal of Wood Science》2010,56(2):169-171
We examined the dissolution of polystyrene into p-cymene and related substances to develop an alternative method for the recycling of expanded polystyrene. The dissolving
power of p-cymene [212.0 g (100 g solvent)−1] to polystyrene at 50°C compared favorably with those of 2-p-cymenol [156.7 g (100 g solvent)−1], (R)-limonene and its structural isomers [181.7–197.1 g (100 g solvent)−1], and Abies leaf oil [84.7 g (100 g solvent)−1]. The favorable solubility of polystyrene into p-cymene can be explained by the solubility parameter. p-Cymene and polystyrene can be recovered almost quantitatively from the polystyrene solution by simple steam distillation. 相似文献
115.
116.
拖拉机行驶路线的自动变更研究 总被引:3,自引:3,他引:0
为了实现拖拉机自动化作业的需要,本研究利用前馈控制和反馈控制相结合的控制方法,设计了拖拉机行驶路线自动变更的非线性反馈控制器。首先,利用非线性最优控制方法,设计了车辆进行行驶路线自动变更的基准轨迹;然后利用LQ最优控制技术,构造了车辆沿着基准轨迹进行行驶路线变更的反馈控制器。最后,利用设计的基准轨迹和反馈控制器进行了实车试验。试验表明,该控制方法具有良好的适应性,所设计的控制器具有良好的响应性和收敛性。 相似文献
117.
Ko Fujioka Ryo Kawabe Alistair J. Hobday Yoshimi Takao Kazushi Miyashita Osamu Sakai Tomoyuki Itoh 《Fisheries Science》2010,76(3):403-410
Acoustic tags were used to examine the spatial and temporal distribution of southern bluefin tuna (SBT) in southern Western Australia, which is in a region where fishery-independent acoustic surveys of the recruitment abundance index of SBT have been historically undertaken. We investigated patterns of SBT distribution within and inshore of the acoustic survey area during three summer seasons. Annual differences in distribution patterns were characterized by two distinctive migration pathways. An inshore-migrating pathway was observed in two seasons (2004/2005 and 2006/2007), with a relatively high proportion of tagged SBT (84.5, 65.0%) migrating inshore of the acoustic survey area. The other pathway was concentrated along the shelf (2005/2006 season), with an estimated 63.3% of tagged SBT moving within the survey area. These variable migration patterns may bias the interannual fluctuations in abundance indices. Current survey methods can be modified to include both inshore and continental shelf areas. This contribution shows that the accuracy of acoustic surveys can be improved by including ecological patterns. 相似文献
118.
119.
Hiroki Yasuma Ryo Nakagawa Takashi Yamakawa Kazushi Miyashita Ichiro Aoki 《Fisheries Science》2009,75(3):545-552
Sound-speed and density contrasts (h and g, respectively), important acoustic material properties, of Japanese sandeel Ammodytes personatus were measured to estimate theoretical target strength (TS). The measured sound-speed contrast of adult fish varied between
1.016 and 1.023 (mean 1.020), and showed temperature dependence. The measured density contrast differed significantly between
juvenile and adult. The density contrast of juvenile varied between 1.017 and 1.024 (1.021), and that of adult varied between
1.026 and 1.038 (1.032). Using these results, TS at 38 and 120 kHz in the fishing season were estimated by an empirical sound
scattering model. TS of an individual fish varied significantly with change of tilt angle. TS of near-dorsal aspect (TSmax) and tilt-averaged TS (TSave) differed by up to 7 dB. At both frequencies, two different TSave−length relationships (TSave = a log L + b) were obtained for adult and juvenile. The coefficients of log L of adult were close to 20, suggesting that backscattering strength was proportional to square of body length. These values
were larger in juvenile (34.0 at 120 kHz, 56.5 at 38 kHz), suggesting that backscattering strength varied drastically with
the cube or fifth power of body length. 相似文献
120.
Induction of stress protein (HSP70) was studied in goldfish (Carassius auratus) reared with bluegills (Lepomis macrochirus), a predator of small fish. HSP70 was identified by Western blotting and quantified by optical density after SDS-PAGE. The expression of HSP70 was significantly enhanced in the brains of goldfish reared with bluegills for 6 and 12 h in a single tank. The hepatopancreas and the kidney were not affected by the treatment. When goldfish were separated from bluegills with a partition net (1×1 cm mesh size), this protein also increased in the brains after 6 h but then returned to the control level after 12 h. When the goldfish and bluegills were kept in separate tanks and were not able to see each other but were connected by circulating water, HSP70 levels in the goldfish were unaffected. Immunohistochemical observations indicated that an anti-HSP70 antibody was found to react predominantly with the optic and vagal lobes of the brains. These results suggest that visual perception plays a primary role in enhancement of HSP70 expression in the goldfish reared with bluegills. 相似文献