邻里空间演化的个体化现象研究—以广州华侨聚居区为例

基于华侨新村建筑形态演变研究,通过质性研究访谈,对在全球化和政治变革影响下广州华侨聚居区——华侨新村个体化现象出现的原因及机制进行分析,发现高围墙所揭示的不仅是物质空间上的边界和隔离,同时是居民交往空间上的边界和隔离的隐喻。由于城市管理模式变革,社区内异质性增高,社区中上阶层对其他的居民的认同感和信任感低,并且在绅士化的冲击下,以老归侨和单位制居民为主的旧情感性关系正在瓦解,新的认知性关系无法建立,实体社区功能弱化,个体化现象在华侨新村内日益普遍。     

浙江省主要河流水沙特征及变化趋势分析

以浙江省主要河流为研究对象,选取11个水文控制站1956~2013年的水沙序列资料,对径流、悬移质泥沙输沙量进行年内变化、年际变化、代际变化的特征分析。运用改进的M-K趋势检验及线性滑动回归分析等方法,系统分析了6大主要河流水沙变化趋势。研究表明:水沙年内、年际变化有一定的相关性,泥沙的变化幅度大于径流的变化幅度,径流变化趋势不显著,但73%的水文控制站的输沙量呈显著下降趋势。     

Seismic activities before and after the impoundment of the Xiangjiaba and Xiluodu reservoirs in the lower Jinsha River

The lower Jinsha River basin is located at the junction of Sichuan and Yunnan provinces in Southwest China, a region with intense tectonic movements and frequent moderate to strong seismic activities. Cascade hydropower stations have been constructed along the lower Jinsha River since 2012. However, research on the effect of the impoundment of large-scale cascade reservoirs in a river basin on local seismic activities is currently lacking. Accurately identifying earthquake locations is essential for studying reservoir-induced earthquakes. Analyzing the spatiotemporal migration process of seismic activities based on complete and precise earthquake relocation is fundamental for determining the fluid diffusion coefficient, constructing fault models for reservoir areas, identifying earthquake types, exploring earthquake mechanisms, and evaluating seismic hazards. The seismicity pattern in the Xiangjiaba and Xiluodu reservoir areas, where seismic activities had been weak for a long time, has changed with the successive impoundment of the two reservoirs, showing microseismic events and seismic clusters. We investigated the spatiotemporal characteristics of seismic activities in the Xiangjiaba and Xiluodu reservoir areas using the waveform cross-correlation-based double-difference relocation technique and the b-value analysis method. We discovered that seismic events after the impoundment of these two reservoirs exhibited different characteristics in different regions. The seismic activities at the Xiluodu dam quickly responded to the rising water level, with the seismic intensity decaying rapidly afterward. These events were concentrated in the limestone strata along both sides of the Jinsha River, with a shallow focal depth, generally within 5 km, and a high b-value of approximately 1.2. Such features are close to those of karst-type earthquakes. Microseismic activities frequent occur on the eastern bank of the Yongshan reservoir section downstream of the Xiluodu dam, with two parallel NW-trending earthquake strips visible after precise earthquake relocation. The M_S5.2 earthquake near Wuji town on August 17, 2014, had prominent foreshocks and aftershocks distributed in a clear NW-trending 20-km-long strip, perpendicular to the riverbank. These seismic events had a low b-value of approximately 0.7. The orientation of the node plane revealed by the strike-slip focal mechanism of the mainshock is consistent with that of the strip formed by the foreshock-mainshock-aftershock sequence, indicating the existence of a NW-striking concealed fault. Seismic activities near the Yanjin-Mabian fault upstream of the Xiangjiaba reservoir area since 2013 were concentrated in a NW-trending strip, with several near EW-trending seismic clusters on its western side, and with the largest event having a magnitude of M_L3.7. So far, the impoundment of the Xiangjiaba and Xiluodu reservoirs has not triggered seismic activities on the large Jinyang-Ebian and Yanjin-Mabian faults nearby.     

长江流域夏季日面雨量精度与不同站数间关系研究

为探讨不同测量站配置数对统计长江流域夏季日面雨量精度的影响,选取金沙江下游、鄂东北、青弋水阳江3个流域作为研究对象,并挑选出不同站网分布,统计各站网分布计算的2016—2018年夏季日面雨量,运用平均绝对误差（MAE）、均方差（MSE）和相关系数（r）三个技术指标来评价各流域夏季日面雨量精度与站数之间的关系。结果表明：各流域夏季日面雨量精度均受站数变化的影响,MAE、MSE均随站数的增加而减小,但当站数增加到一定数量之后趋于稳定,r也有相同的变化规律,只是随站数增加而增大。同时,通过计算三个技术指标随站数平均变化值,定量揭示了以上变化规律并得到金下、鄂东北、青弋水阳江流域代表性站数分别为405站、293站、126站,与现有站数相比,分别减少25.1%、55.8%、56.6%,可为计算长江流域夏季日面雨量选用站数和站网布局提供参考。     

地面测控站分布对北斗卫星精密定轨的影响

北斗卫星精确定轨是北斗卫星导航系统应用与服务的核心技术,而地面测控站的分布是影响其精度的主要原因之一。针对北斗卫星地面跟踪站的现状,该文基于几何法定轨的基本原理,将卫星定轨的观测方程线性化,根据位置精度衰减因子值的构成,分析了测站分布与卫星定轨精度之间的关系。通过3种实验方案,对比不同测站分布和测站数量对北斗卫星定轨精度和计算效率的影响。实验结果表明:仅利用现有iGMAS站和BETS站的观测数据,很难获取高精度的北斗定轨结果;增加国际MGEX的北斗数据后,定轨精度有明显提高,尤其体现在GEO卫星切线方向;利用40个全球均匀分布的北斗站与利用70个站的定轨精度相当,但前者的解算效率较后者可提高近1倍。     

State‐led talent return migration programme and the doubly neglected ‘Malaysian diaspora’: Whose diaspora,what citizenship,whose development?

This paper questions the assumptions of ‘diaspora’, ‘citizenship’ and ‘development’ underlying diaspora strategies targeting a specific pool of overseas Malaysian ‘talent’ migrants. I examine the Malaysian state's discursive attempts to construct a carefully contained economic ‘diaspora'—the ‘Malaysian diaspora'—through its talent return migration programme. In this process, there is a portion of the ‘Malaysian diaspora’, especially non‐bumiputeras (sons of soil), who are doubly neglected and excluded: first, from access to full and equal citizenship (which arguably contributed to their emigration in the first place); and second, from eligibility and recognition to participate in Malaysia's talent return migration programme. However, recent political activism calling for electoral reform and overseas voting rights challenges state‐constructed visions of the ‘diaspora’ and their expected roles in advancing ‘development’. This paper concludes by highlighting questions raised by the Malaysian case, linking these explicitly to how diaspora strategies—as they have been conceived, practised and contested—challenge the broader Migration and Development paradigm.     

改进量子粒子群算法在水电站群优化调度中的应用

针对量子粒子群算法求解水电站群优化调度问题存在的早熟收敛、寻优能力欠佳等缺陷,从种群初始化、进化和变异等方面提出了改进量子粒子群算法。该方法引入混沌搜索增强初始种群质量;通过加权更新种群最优位置中心改善种群进化模式并提升收敛速度;利用邻域变异搜索增加种群多样性避免早熟收敛。同时依据问题特点设计了矩阵实数编码方式与复杂约束处理方法。乌江梯级综合对比分析表明所提方法能切实保证快速获得高质量优化调度结果,有效提高梯级水能利用率,如长序列模拟调度较逐步优化算法分别减少8.9%的弃水和72.3%的耗时,是一种适用于大规模水电站群优化调度的高效实用方法。     

电站建设对澜沧江-湄公河泥沙年内分配的影响

采用澜沧江漫湾电站上游旧州站和下游允景洪、清盛站1987~2003 年逐月悬移质泥沙含量实测资料, 分析对比了三站年内泥沙分配不均匀系数、集中度和集中期、变化幅度等特性。将上述参数与澜沧江上游干流漫湾与大朝山电站建设的响应进行关联研究, 分析电站建设进程对河道输沙变化的驱动作用。结果表明: (1) 旧州水文站泥沙年内分配与区域气候变化 (降水) 趋势一致, 研究时段内不均匀性系数呈上升趋势, 维持天然河道输沙特性; 允景洪和 清盛水文站的泥沙年内分配不均匀性系数对电站建设等人类活动的响应程度不一致, 允景洪站泥沙含量不均匀系数先减小后急剧增加, 而清盛站呈微弱减小态势。(2) 旧州水文站泥沙年 内分配集中度及集中期基本无变化; 允景洪与清盛水文站的泥沙年内分配集中度变化较大, 泥沙集中期在在电站施工的高峰期(1987~1992 年、1997~2003 年) 后延, 且不同步, 允景洪在漫湾施工期后延5~6 天, 而清盛则后延将近半个月,而在大朝山施工期, 允景洪的后延响应 却明显于清盛。(3) 旧州站相对、绝对泥沙变幅逐时段递增, 允景洪站年内最大与最小月泥沙含量的相对、绝对变化幅度均减小, 清盛站泥沙含量的相对变化幅度却先增后减, 绝对变化 幅度则一直减小。三站泥沙年内极值变幅以及电站建设前后的响应差异, 说明三站泥沙变化的驱动因子有明显不同。这些关于泥沙含量年内分配特征规律的发现, 为研究澜沧江干流电站建设对上下游泥沙变化以及跨境影响的科学评价提供了新的佐证。     

星座异构基准站网虚拟参考站数据生成方法

针对各地现有卫星导航定位基准站可用星座存在差异性的问题,提出了按星座分别生成虚拟参考站数据的方法。该方法通过修正接收机钟差影响,实现了多个参考站作为主参考站生成同一个站点的虚拟观测值,有效避免了单个主参考站星座兼容性的影响,可为流动站提供更多的可用卫星。试验针对部分基准站不兼容北斗卫星的情况,分别在开阔区域和房角区域测试了按星座组网前后流动站的定位性能。结果显示：更多基准站参与服务能够改善虚拟参考站数据质量;按星座组网后流动站的定位质量更优,尤其可以显著改善流动站在房角等有遮挡区域的可用性和定位质量。研究成果对于有效整合当前各类基准站数据资源、提升服务对星座的兼容性具有实用价值。     

合作伙伴关系视角下的海外园区政策移动性研究——以泰中罗勇工业园为例

政策移动性是国际政治地理学研究的经典理论。作为包容性全球化和“一带一路”倡议重要空间载体的海外园区,是检验政策移动性理论框架的新兴空间载体。本文以泰中罗勇工业园为例,以合作伙伴为切入点,检验政策移动性理论在海外园区的适用性,并强调海外园区的政策移动性是渐进发展的过程,关键角色的合作伙伴关系对于政策移动性起着重要作用。本文系统分析了泰中罗勇工业园的制度背景、主体合作伙伴,甄别出国家、地方政府、主导企业等关键角色的合作伙伴关系及其在税收、土地、人才等要素政策移动性过程中的机制。在此基础上,提出未来“一带一路”建设中海外园区可持续发展的政策建议。