日本交通体系的特征与经验借鉴     

王开泳  陈田  高晓路 《世界地理研究》2008,17(1):112-118

作为发达国家的典型代表,日本在交通体系的规划布局比较完善,已经形成了快速便捷、四通八达的交通体系。结合笔者去日本考察的实际经历,总结了日本在交通路网结构、快速轨道交通的布局、交通换乘、交通工具的人性化设计以及交通规章制度方面的先进经验。并结合中国交通体系建设中存在的问题和不足提出今后需要改进和完善的几个主要方面,为中国的交通体系建设提供经验借鉴。  相似文献   

中日东海石油之争及对我国的启示     

张晓芳  钟全林  邵秀英  陈世发 《世界地理研究》2008,27(3):43-49

随着世界经济的发展,各国对石油的依赖程度越来越高,于是石油被成为经济的“晴雨表”。在石油领域的争夺也日趋激烈,各国纷纷建立自己的石油储备体系,以保障自己的石油安全。中日东海石油之争愈演愈烈,其不仅涉及到我国的石油安全、经济安全,还涉及到政治安全乃至国家安全。关注东海问题,既是维护我国经济和政治安全的需要,更是建立我国能源安全战略的重要组成。  相似文献   

Comparison of the Clay Fraction of Ariake Clay Determined by Japanese and ASTM Standards     

Anil Kumar Mishra  Aflakhur Ridlo  Masami Ohtsubo  Takahiro Higashi 《Marine Georesources & Geotechnology》2013,31(2):110-116

This study compares the clay fraction percentage determined by Japanese standard JIS A1204/JGS 0131 and ASTM standard D422-63 for the clay samples obtained from the surface of sea bottom sediments in Ariake Bay, Japan. These two standards differ in the amount of dispersant to be added for the dispersion of soil suspensions. The Japanese and ASTM standards suggest adding sodium hexametaphosphate solution as the dispersant so that the final concentration of the dispersant in soil suspension for hydrometer test becomes 2 and 5 g/L, respectively. The test results indicated that the treatment by the Japanese standard gave less dispersion in the soil suspension compared to the ASTM standard, and hence resulted in the underestimation of clay fraction percentage of all the samples.  相似文献   

Resource Evaluation and Some Genetic Aspects of Indium in the Japanese Ore Deposits   总被引：7，自引：1，他引：7  

Shunso Ishihara    Kenichi Hoshino  Hiroyasu Murakami  Yuji Endo 《Resource Geology》2006,56(3):347-364

Abstract. There have been two primary sources for industrial indium; one from massive sulfides, while the other is dissemination-veins and skarns, related to felsic igneous rocks. The latter group of the In-bearing deposits is abundant in the Japanese Islands. Indium occurs as In-minerals such as sakuraiite, roquesite, laforetite and many unidentified minerals, but the majority is contained as an impurity in sphalerite, and tin and copper sulfides. Average grades of the ores from which indium has been extracted vary from a few ppm (e.g., Kosaka mine) to more than 300 ppm (Toyoha mine). The amount of indium in all the major basemetal deposits is estimated by analyzing representative samples. The main indium deposits are subvolcanic and tin-poly-metallic vein types. The largest one is Toyoha mine (4,700 tons hi) and the Ashio mine (ca. 1,200 tons In) was found to be the second largest. Many small occurrences, were recognized in the Miocene magnetite-series belt, besides the classic occurrences in the ilmenite-series granitic terrains of SW Japan, including the Ikuno and Akenobe tin(-tungsten) polymetallic veins, located in the northern margin of the late Cretaceous Sanyo ilmenite-series province. Magnetite-series magmas with deep source are necessary to concentrate sulfur in the magma chamber but sedimentary source rocks and their reducing agents are needed to collect and to precipitate indium. The Japanese islands are essentially accretionary terrains intruded by various deep oxidized magmas; thus forming magnetite/ilmenite-series paired belts, which are sometimes mixed. This unique geologic setting may be the most fundamental reason why indium is rich in vein-type deposits of the Japanese Island arcs.  相似文献   

Secular crustal deformation and interplate coupling of the Japanese Islands as deduced from continuous GPS array, 1996–2001     

Gamal El-Fiky  Teruyuki Kato 《Tectonophysics》2006,422(1-4):1-22

Data from the nation-wide GPS continuous tracking network that has been operated by the Geographical Survey Institute of Japan since April 1996 were used to study crustal deformation in the Japanese Islands. We first extracted site coordinate from daily SINEX files for the period from April 1, 1996 to February 24, 2001. Since raw time series of station coordinates include coseismic and postseismic displacements as well as seasonal variation, we model each time series as a combination of linear and trigonometric functions and jumps for episodic events. Estimated velocities were converted into a kinematic reference frame [Heki, K., 1996. Horizontal and vertical crustal movements from three-dimensional very long baseline interferometry kinematic reference frame: implication for reversal timescale revision. J. Geophys. Res., 101: 3187–3198.] to discuss the crustal deformation relative to the stable interior of the Eurasian plate. A Least-Squares Prediction technique has been used to segregate the signal and noise in horizontal as well as vertical velocities. Estimated horizontal signals (horizontal displacement rates) were then differentiated in space to calculate principal components of strain. Dilatations, maximum shear strains, and principal axes of strain clearly portray tectonic environments of the Japanese Islands. On the other hand, the interseismic vertical deformation field of the Japanese islands is derived for the same GPS data interval. The GPS vertical velocities are combined with 31 year tide gage records to estimate absolute vertical velocity. The results of vertical deformation show that (1) the existence of clear uplift of about 6 mm/yr in Shikoku and Kii Peninsula, whereas pattern of subsidence is observed in the coast of Kyushu district. This might reflect strong coupling between the Philippine Sea plate and overriding plate at the Nankai Trough and weak coupling off Kyushu, (2) no clear vertical deformation pattern exists along the Pacific coast of northeastern Japan. This might be due to the long distance between the plate boundary (Japan trench) and overriding plate where GPS sites are located, (3) significant uplift is observed in the southwestern part of Hokkaido and in northeastern Tohoku along the Japan Sea coast. This is possibly due to the viscoelastic rebound of the 1983 Japan Sea (M_w 7.7) and the 1993 Hokkaido–Nansei–Oki (M_w 7.8) earthquakes and/or associated with distributed compression of incipient subduction there. We then estimate the elastic deformation of the Japanese Islands caused by interseismic loading of the Pacific and Philippine Sea subduction plates. The elastic models account for most of the observed horizontal velocity field if the subduction movement of the Philippine Sea Plate is 100% locked and if that of the Pacific Plate is 70% locked. However, the best fit for vertical velocity ranges from 80% to 100% coupling factor in southwestern Japan and only 50% in northeastern Japan. Since horizontal data does not permit the separation of rigid plate motion and interplate coupling because horizontal velocities include both contributions, we used the vertical velocities to discriminate between them. So, we can say there is strong interplate coupling (80%–100%) over the Nankaido subduction zone, whereas it is about 50% only over the Kurile–Japan trench.  相似文献   

实验微粒饲料中花生四烯酸含量对牙鲆(Paralichthys olivaceus)仔稚鱼生长、存活的影响   总被引：4，自引：0，他引：4  

刘镜恪  陈晓琳  李岿然  徐世宏 《海洋与湖沼》2005,36(5):418-422

采用花生四烯酸即廿碳四烯酸（AA, 20∶4n-6）含量梯度法,制备了四种n-3HUFA含量相等、DHA/EPA比例相同、AA含量分别为0.06%、1.00%、1.5%、2.0%的实验微粒饲料,进行了AA的不同含量对牙鲆仔稚鱼生长、存活、体内相关成分以及对外部压力耐受性的影响研究.26天的养殖试验结果表明,当牙鲆仔稚鱼实验微粒饲料中AA的含量为1.5%时,牙鲆仔稚鱼的生长、存活以及对不同压力的耐受性都达到最佳.养殖试验结束后,对稚鱼体内相关成分的分析结果表明,稚鱼体内AA的含量随着实验微粒饲料中AA含量的增加而增加.  相似文献   

不同放养密度和混养石莼对牙Ping鱼种生长的影响   总被引：1，自引：0，他引：1       下载免费PDF全文

王吉桥  李岩 《海洋科学》2003,27(2):1-4

牙鲆的放养密度以所放养鱼腹面表面积之和占养殖池底面积的百分数 ( % )表示。在直径为27cm、容积为40L的塑料桶中放置网箱 ,按网箱底面积48 % ,74 %或100 %的密度放养牙鲆 (Paralichthysolivaceus)幼鱼 (体质量1.86g±0.18g,全长6.3cm±0.27cm)。同时另在放养密度100%组中混养石莼40.00g。经45d饲养 ,混养石莼组中的牙鲆生长最快 ,水质好 ,饲养系数最低。在单养组中 ,牙鲆生长速度由快至慢依次为48 %组>74%组>100%组。牙鲆体长增长和体质量增长速度最快的密度分别为80 %～100%和100%～110 % ,低于或高于此密度鱼的增长均减慢。  相似文献   

Changes in serum thyroid hormone levels and thyroid gland activity of artificially maturing female Japanese eel(Anguilla japonica)     

Qu Xiancheng  Massaki Nagae  Sinji Adachi  Kohei Yamauchi 《海洋学报(英文版)》2003,22(1):111-122

In order to evaluate the involvement of the thyroid gland in reproduction, thyroid functioning was described in female cultivated Japanese eel (Anguilla japonica) in progressive stages of sexual maturation induced by chum salmon pituitary homogenate (SPH) treatment. Serum thyroid hormones, thyroxine (T4) and triiodothyronine (T3) were also measured in each stage. Thyroid gland activity (epithelial cell height) was high before SPH injection (previtellogenic stage), further increasing at the early vitellogenic stage, thereafter decreasing to late vitellogenic and migratory nucleus stages. The profiles of both T3 and T4 changed during vitellogenesis, being high during previtellogenic and early vitellogenic stages, and subsequently declining, thus mimicking thyroid gland activity. These results suggest that the thyroid has relation with eel ovarian development during artificial maturation.  相似文献   

基于企业点数据的在京日企空间集聚模式   总被引：2，自引：0，他引：2  

刘桂梅  王茂军 《世界地理研究》2021,30(5):925-936

基于驻京日企微观空间数据,根据企业母公司所属行业类型,对比探析不同行业企业的空间集聚/分散态势及其演化趋势,利用DO指数法,科学测定在京日企空间集聚范围。研究发现：（1）在“纯距离”条件下,原材料密集型制造业集聚尺度为35-60km,资本和技术密集型制造业集聚尺度为20-28km,生产性服务业的集聚尺度为10-18km,而生活服务业空间分布则较为随机;在考虑企业规模条件下,各个行业集聚尺度则大相径庭,集聚（分散）指数显著升高;（2）服务业与制造业之间存在明显的互斥现象,对于制造业而言互斥状态并不显著,但对于服务业而言在空间上与制造业存在明显的互斥现象,且互斥尺度发生在22-28km上;（3）随着时间的推移,原材料密集型制造业在空间上的分布模式基本趋于稳定,资本和技术密集型制造业新-老企业在空间上愈发集聚,共聚尺度发生在18—30km范围内;生产性服务业与生活服务业的新-老企业分布模式基本相似,新入驻企业依托于前期入驻企业,接触扩散、就近分布,在空间上趋于共栖。  相似文献   

牙鲆体表溃烂综合症病理组织观察     

周丽  战文斌  宋微波  宋春华 《中国海洋大学学报(自然科学版)》2000,30(4)

报道了牙鲆养殖过程中发生的体表溃烂综合症的病理组织变化。该病的病原有盾纤类纤毛虫指状拟舟虫和致病菌兔莫拉氏菌。指状拟舟虫不仅寄生于牙鲆体表皮肤、鳍 ,亦可侵入腹腔、肾脏、肌肉、心脏甚至脑。兔莫拉氏菌大量寄生于心脏血液中 ,随血液循环至各组织器官 ,引起牙鲆肝脏、肾脏及脾脏组织病变。指状拟舟虫和兔莫拉氏菌共同导致牙鲆死亡。  相似文献