Land use change of Kitakyushu based on landscape ecology and Markov model

Based on four phases of TM images acquired in 1990, 1995, 2000 and 2005, this paper took Kitakyushu in Japan as a case study to analyze spatial change of land use landscape and corresponding effects on environmental issues guided by landscape ecology theory in virtue of combining technology of Remote Sensing with GIS. Firstly, land use types were divided into 6 classes (farmland, mountain, forestland, water body, urban land and unused land) according to national classification standard of land use, comprehensible ability of TM image and purpose of this study. Secondly, following the theory of landscape ecology analysis, 11 typical landscape indices were abstracted to evaluate the environmental effects and spatial feature changes of land use. Research results indicated that land use has grown more and more diversified and unbalanced, human activities have disturbed the landscape more seriously. Finally, transfer matrix of Markov was applied to forecast change process of land use in the future different periods, and then potential land use changes were also simulated from 2010 to 2050. Results showed that conversion tendency for all types of land use in Kitakyushu into urban construction land were enhanced. The study was anticipated to help local authorities better understand and address a complex land use system, and develop improved land use management strategies that could better balance urban expansion and ecological conservation.     

中国东北地区地震活动的动力背景及其时空特征分析

本文根据日本海沟、 西太平洋板块俯冲与中国东北地区深源地震的关系、 中国东北地区深源地震的平均震源机制结果以及日本海沟强震与中国东北地区浅源地震的关联性, 概述了中国东北地区地震活动的动力背景, 说明中国东北地区的深源地震与西太平洋板块俯冲具有成因上的联系, 中国东北深震是西太平洋板块高速度、 小倾角向欧亚大陆下俯冲的结果。 中国东北地区深源地震、 浅源地震的时空分布以及依据浅源地震的分期统计资料表明, 中国东北地区浅源地震经历了5个活动周期, 每个活动周期浅源地震的时空分布具有个性差异, 在此基础上, 分析了浅源地震每个活动周期结束地震时空分布特征, 发现每个活动周期结束地震前均经历了平均约4.19年的长时间平静, 结束地震以成对地震为主要表现形式。     

1990年代以来日本大都市圈的结构变化

基于既有研究综述了1990年代以来日本大都市圈的发展动态。1990年代初期,东京都市圈郊区扩张的势头停止,取而代之的是中心区的人口增加,即人口的都心回流趋向。究其原因,泡沫经济中持续上升的地价于1986~1991年间开始回落,由此引发了城市中心区的住宅建设,带动了诸多价格适中的商品住房供给。此外,伴随少子化,人们为追求住宅面积而迁往郊区的势头也已减弱;日益增多的老年人反而为了追求便利性从郊区的独立住宅迁往市中心居住,郊区一些公共交通不便的居住区人口开始减少。在地方都市圈,类似的现象也已出现,甚至还存在总人口减少的可能。在此状况下,抑制郊区开发、建设紧凑城市的规划政策开始受到重视。     

AMS analysis of I in Japanese soil samples collected from background areas far from nuclear facilities

Analytical procedures in the determination of iodine-129 (half-life: 1.6×10⁷ y) have been studied using accelerator mass spectrometry (AMS), with special references to the separation procedures of iodine from soil samples for the AMS measurement. Iodine was successfully volatilized from soil samples by pyrohydrolysis at 1000 °C and collected in a trap solution. Iodine was purified from the matrix by solvent extraction. Finally, it was precipitated as silver iodide to make a target for AMS. In order to obtain information on the ¹²⁹I/¹²⁷I ratio in a chemical blank (or iodine carrier), we have determined the ratios in several iodine reagents and found that the ratios fell in a narrow range around 1.7×10⁻¹³. The detection limit for soil sample (1 g material) by the present method was about 0.01 mBq/kg or 4×10⁻¹¹ as the ratio of stable iodine (¹²⁹I/¹²⁷I ratio), i.e. these values were much better than that by neutron activation analysis (NAA) used in our previous studies. We have applied this method in the analysis of soil samples collected from different places in Japan. We could successfully determine ¹²⁹I in soil samples with low ¹²⁹I concentrations, which could not be detected by NAA. Sample size necessary for the soil analysis by AMS was only about 0.5 g or less, whereas about 100 g of the sample were required for NAA [Muramatsu, Y., Ohmomo, Y., 1986. Iodine-129 and iodine-127 in environmental samples collected from Tokaimura/ Ibaraki, Japan. Sci. Total Environ. 48, 33-43]. Using this method, new data were obtained for the ¹²⁹I levels in 20 soil samples collected from background areas far from nuclear facilities, and the ranges were 1.4×10⁻⁵−4.5×10⁻³ Bq/kg as ¹²⁹I concentrations and 3.9×10⁻¹¹−2.2×10⁻⁸ as ¹²⁹I/¹²⁷I ratios. These values are useful in understanding the ¹²⁹I levels in Japanese environments. Higher ¹²⁹I concentrations were observed in forest soils than those in field and rice paddy soils should be related to the interception effect of atmospheric ¹²⁹I due to tree canopies. Relatively high ¹²⁹I/¹²⁷I ratios found in rice paddy soils could be explained by their low stable iodine concentrations which were caused by the desorption of stable iodine from the rice paddies during the cultivation.     

Mixed layer in the Sea of Japan: numerical simulation and long-term data analysis

Seasonal variation and topography of the mixed layer in the Sea of Japan are studied by comparison of results from long-term observation data analysis and from numerical simulation with the MHI oceanic model (Shapiro. 1998. Marine Hydrophysical Journal, 6:26～40). The data are retrieved from Oceanographic Atlas of the Bering Sea, Okhotsk Sea, and Japan/East Sea (Rostov, Rostov, Dmitrieva, et al. 2003. Pacific Oceanography, 1 (1):70-72). The simulated and long-term patterns are compared. An impact of surface buoyancy flux, wind, and convergence/divergence of surface currents upon the mixed layer in the Sea of Japan is analyzed.     

Geochronological characterization and petrogenesis of granitoids in the Ryoke belt, Southwest Japan Arc: constraints from K–Ar, Rb–Sr and Sm-Nd systematics

Abstract Rb–Sr and K–Ar chronological studies were carried out on granitic and metamorphic rocks in the Ina, Awaji Island and eastern Sanuki districts, Southwest Japan to investigate the timing of intrusion of the granitoids in the Ryoke belt. Intrusions of 'younger' Ryoke granitic magmas took place in the Ina district between 120 Ma and 70 Ma, and cooling began immediately after the emplacement of the youngest granitic bodies. Igneous activity in Awaji Island was initiated at 100 Ma and continued to 75 Ma. Along-arc variations of Rb–Sr whole-rock isochron ages suggest that magmatism began everywhere in the Ryoke and San-yo belts at almost the same time ( ca 120 Ma). The last magmatism took place in the eastern part of both belts. Rb–Sr and K–Ar mineral ages for the granitoids young eastwards. The age data suggest that the Ryoke belt was uplifted just after the termination of igneous activity. Initial Sr and Nd isotopic ratios for the Ryoke granitoids indicate that most were derived from magmas produced in the lower crust and/or upper mantle with uniform Sr and Nd isotopic compositions. Several granitoids, however, exhibit evidence of assimilation of Ryoke metamorphic rocks or older Precambrian crustal rocks beneath the Ryoke belt.     

日本东京煤气管网地震实时防灾系统综述

以东京煤气公司为例,论述了高、中、低压煤气管网的地震实时防灾系统－感震自动隔断系统,地震警报系统、无线电远程监视与操作系统、远程煤气泄漏监测系统等。     

2011年日本9.0级地震的同震位错以及震后应力松弛过程对中国大陆的影响

本文基于日本GEONET的GPS观测资料, 对日本2011年9.0级地震的同震和震后形变过程进行了研究。 结果表明, 日本9.0级地震使中国大陆出现了显著的同震位移, 几乎对整个中国大陆都有影响。 位移量在中国东北地区最大, 接近甚至超过该地区的年运动速率。 震后1年观测到的形变基本上可由沿着断层面的蠕滑进行模拟, 粘弹松弛的贡献不大。 根据所得到的震后蠕滑模型, 震后1年形变所释放的能量等同于发生一个8.7级地震, 其影响主要在东部地区, 最大位移约为年运动速率的30%。 预测在未来2年, 该地震的影响范围将逐渐减小。 地震造成的粘弹松弛在未来50~100年的尺度上, 对东北地区有拉张效应。 日本9.0级地震整体上起到了卸载中国大陆在板块间挤压过程中所累积应变能的作用, 因此该地震发生后的几个月, 中国大陆东部的地震活动水平较震前明显降低。     

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日本早期社会主义思潮与中国革命

明治维新之后,社会主义思潮在日本得以兴起。日本是社会主义思潮在亚洲最先传播、社会主义运动历史最长的国家。20世纪初日本社会主义思想的传播掀起了史无前例的高潮,对中国留学生产生了重要影响。社会主义思想通过日本留学生等渠道传播到中国来,梁启超、孙中山、李大钊等先进的中国知识分子,通过翻译、比较、吸收、宣传,推动了中国早期革命。