全球视角下中国城镇化进程及其碳排放效应的比较研究

高质量的城镇化发展模式是中国实现现代化和低碳绿色发展转型的关键。本文利用1990―2020年世界195个国家(地区)的面板数据,从人口、空间、经济、社会4个维度测度各个国家(地区)的综合城镇化水平,并基于STIRPAT模型和EKC理论对比分析中国及不同收入群体国家城镇化对碳排放的影响机制。研究结果表明:①世界各国(地区)的综合城镇化水平整体呈现出增长的趋势,其中亚洲和欧洲地区的提升最为明显,中国的综合城镇化水平则呈现出起步低、速度快的发展趋势。②世界各国(地区)的城镇化发展质量正在稳步提升,综合城镇化的发展质量与区域的发展阶段具有密切的相关性,高收入国家(地区)的城镇化发展主要是由经济城镇化和社会城镇化主导的,而低收入国家(地区)城镇化的主导类型则是人口城镇化和空间城镇化,中国的城镇化进程逐渐从以城镇人口带动的“量”转变为协调发展的“质”,但仍与发达国家存在较大差距。③高收入、高城镇化和低收入国家(地区)综合城镇化与人均碳排放上存在“倒U型”曲线关系,中低收入、中高城镇化和低城镇化国家(地区)存在“U型”曲线关系,目前中国还处于人均碳排放随着综合城镇化水平的提升而上升的阶段,“倒U”曲线拐点还未出现,推动经济城镇化和社会城镇化水平的提升则是实现碳达峰的关键。因此,未来中国需要协调城镇化发展、居民生活水平提升和节能减排之间的关系,在提高城镇化质量的同时降低城镇化对碳排放的贡献。

基于文献计量学的林下套种研究热点及进展

采用文献计量学软件CiteSpace对林下套种研究现状及热点进行可视化分析,为林下套种今后的研究发展方向提供借鉴。基于CNKI数据库进行文献检索,共纳入符合标准文献942篇,对发文量、发文机构、作者,关键词共现、聚类、突现进行可视化分析。结果表明:林下套种研究发文量总体呈增长趋势。国内主要研究机构有福建农林大学林学院、福建省林业科学研究院、福建省永安市林业局等。随着时间发展该领域从对套种模式的探索到套种模式优化及其经济与生态效益研究转变。林下套种是一种综合利用和管理森林资源的经济模式,可以产生很高的经济价值、生态价值和社会价值。只有充分认识到林下套种模式的重要性,加强研究和实践,才能推动其在实践中的广泛应用和推广。

蛭石絮凝剂一级强化絮凝预处理皮革废水的研究

针对悬浮颗粒物多、有机污染物浓度高的皮革废水,使用生态型无生物毒性的蛭石絮凝剂,进行一级强化絮凝预处理,结合阳离子助凝剂C-PAM,并且参考传统无机絮凝剂PAC,分别调查蛭石絮凝剂对皮革废水的絮凝效果、C-PAM的协同效应以及与PAC相比之下的絮凝沉降速度。由实验结果可知,蛭石絮凝剂对皮革废水具有很好的絮凝效果,在最佳投加量为6.0 g/L时,上清液的COD、SS、浊度、TP和NH_(3)-N的去除率分别为62.1%、94.5%、97.9%、88.6%和19.3%;在此基础上,阳离子C-PAM为12 mg/L最佳投加量下,上清液的COD、SS、浊度要比只有蛭石絮凝剂的去除率再度增加34.3%、52.4%和54.7%,总去除率分别达到75.1%、97.6%和98.9%,对TP和NH_(3)-N无机物离子去除的影响很小;絮凝后上清液中的重金属和硫化物仍然满足国家排放标准,不因絮凝而超标。相比于PAC,蛭石絮凝剂具有更好的絮凝和沉降效果,在C-PAC协同下,蛭石絮凝剂2 min就基本完成沉降,而PAC却刚刚开始,即使15min后,蛭石絮凝剂的沉积物体积也只有PAC沉积物体积的1/8。有望成为未来本行业中一个重要的处理模式。

武功山重点保护植物区系特征分析

通过野外调查和资料整理,对武功山地区的国家重点保护植物的数量特征、区系特征、生态习性与生长环境特点进行分析,结果表明:1)武功山地区共有国家重点保护植物27科41属57种。2)武功山国家重点保护植物区系成分多样,具有较明显的热带性质。其中,石松类与蕨类植物科、属、种分别可划分为2种、4种、4种分布类型,其中科、属成分均为热带性质成分,种的R/T值约为1.33,热带性质成分略占优势;种子植物属、种可分别划分为10种、6种分布类型,区系热带性与温带性类型的比值(R/T值)分别约为1.28、1.67,该区属的热带成分略占优势,种的地理成分中以热带成分为主。3)武功山国家重点保护植物区系具有起源古老的特性,其中中国特有分布属有3属(均为单型属),中国特有分布种有24种,它们分别占总属数的8.57%、占总种数的48.98%。4)武功山国家重点保护植物主要分布于中低海拔区域,生长于沟谷阔叶林中,其生活型以草本为主。

基于文献计量学的毛竹扩张研究现状可视化分析

【目的】通过CiteSpace文献计量学软件总结毛竹扩张方向取得的研究进展,为森林生态系统的保障提供参考。【方法】基于CNKI及WOS数据库进行文献检索,共纳入文献280篇,对发文量、发文机构、作者,关键词共现、聚类、突现进行可视化分析。【结果】毛竹扩张研究年发文量总体呈增长趋势,国外对于该领域研究起步早,但国内对该领域研究深度及进展远超国外。WOS中相关文献的研究团队主要为国内团队。国内外研究内容主要集中于毛竹扩张的过程与机制及其对森林生态系统的影响。【结论】毛竹扩张对森林生态系统会造成多方面的负面影响,深入研究毛竹扩张机制及其影响才能对其有效管控。

装配式超高墩连续刚构桥碰撞响应及影响研究

灌浆套筒连接装配式超高墩连续刚构桥与边联的动力特性差异显著,地震作用下易与边联发生碰撞。本文采用OpenSees建立了CFRB-FSP(主桥)与边联碰撞模型,探究了非长周期地震动、近断层脉冲型地震动作用下两者纵桥向的碰撞响应及其影响。结果表明,相同PGA作用下,近断层脉冲型地震动作用下的峰值碰撞力比非长周期激励下的大;峰值碰撞力随初始间隙、碰撞刚度以及跨径、墩高的增大而增大;CRFB-FSP主梁峰值位移随主梁跨径、墩高的增大而增大;墩底峰值弯矩随跨径的增大而增大,但随墩高的增高而减小,这与高阶振型的参与有关;碰撞后,CRFB-FSP的主梁峰值位移、墩底峰值弯矩都有所减小,减小率随跨径、墩高的增大而增大。

基于标准化控制的桩基快速施工技术研究

桩基作为桥梁下部结构重要组成部分之一,其施工具有隐蔽性强、可探知度差等特点。目前桥梁桩基施工技术工艺较为成熟,但实际应用中标准化施工仍受现场环境、人为因素等限制,间接对桩基成孔造成一定的质量影响。以标准化施工作为研究方向,利用新兴CPS控制系统,有机融合3C技术,研发一套符合绿色智能、标准高效的规范化施工体系,有利于提高桩基工艺效率及结构质量,同时为上部承台、墩身和桥梁等结构提供稳定可靠的基础。

服务业与多维城镇化的耦合协调研究——以广州市为例

通过借鉴物理学耦合模型测算广州市服务业与综合城镇化及其子系统的耦合协调性,对不同层次内部耦合协调状态的特点以及服务业和城镇化协调发展的内在机制进行了深入探讨。研究发现:2000—2017年,广州的服务业和综合城镇化水平大幅持续上升,二者整体协调发展态势良好,其耦合协调度跨度较大,由0.1710增长到0.9741,从低协调耦合阶段上升至极耦合协调阶段。服务业与4类城镇化子系统的耦合结果显示:人口城镇化、经济城镇化和服务业的耦合协调度处于持续上升状态,而社会城镇化、空间城镇化,尤其是后者和服务业的耦合协调度的上升波动性相对较大;人口城镇化、社会城镇化、空间城镇化与服务业的良好耦合对综合城镇化与服务业的协调发展起拉动作用,而经济城镇化这一子系统则起阻滞作用;保持拉动优势,解决阻滞劣势是加快广州城市发展的良好路径。

乡村振兴背景下社会调查研究教学改革

乡村振兴战略是破解“三农”问题和建设社会主义现代化国家的战略举措,其实施需要乡村社会调查研究以及人才培育的关键支撑。文章通过解读乡村振兴战略,提出地理学和城乡规划专业对社会调查研究的新教学目标与任务,分析当前社会调查研究在教学课程体系、教学内容和教学模式中的问题和不足,探讨社会调查研究教学改革的新路径。新时代社会调查研究应丰富乡村知识版块,构建“理论-调研-竞赛-规划”的教学课程培养体系,提高师生的乡村情怀和关注度;综合运用新理论、新技术和新方法来分析乡村发展面临困境与问题;并通过革新教学模式和转变考核机制来增强学生的专业水平和综合素质,为乡村振兴战略培育更多有情怀、有本领和有经验的综合人才。

粤港澳大湾区知识网络空间结构演化特征与影响机制

以2000-2018年国内外期刊数据库合作论文数据为基础,借助社会网络分析和空间结构指数法分析了粤港澳大湾区知识空间网络结构演化特征与影响因素,结果发现:1)知识网络格局由广州的“一家独大”逐渐演变为广州、深圳、香港“齐头并进”的发展态势.香港虽然处于知识网络的核心位置,但受行政壁垒的影响,主要与广州、深圳高等级的城市建立紧密的知识合作联系.2)粤港澳大湾区知识联系网络呈现“核心—边缘”结构,西部地区知识联系远低于东部地区,虽然研究期内湾区的知识网络的极化特征得到一定的缓解,但不均衡性仍然显著.3)湾区知识活动主体的自身需求是促进城市间知识合作的内在驱动力,知识环境和知识联系通道是区域知识合作网络外在推动力,在内生作用和外生作用的共同影响下,知识合作产出得以实现,粤港澳大湾区知识网络得以发展.

基于图像边缘特征的零件分类与定位算法

本论文提出了一种基于图像边缘特征的零件分类与定位算法。算法首先对图像腐蚀膨胀等预处理,然后通过边缘检测得零件的完整边缘轮廓,然后对零件边缘轮廓图像使用方向梯度直方图(HOG)构造训练数据,并采用支持向量机(SVM)在训练数据上训练分类识别模型,最后进行检测。根据检测结果获得图像中零件的种类和位置信息,然后使用棋盘格标定的方法来确定深度。标定时,取标定板上的两个点来计算深度,根据已知的深度,获取实际抓取点的两个图像坐标系的x,y值,计算世界坐标系坐标。此系统能解决零件分类、定位问题,能广泛运用于生产线引导工业机器人进行零件抓取。

Structure of Chinese City Network as Driven by Technological Knowledge Flows

Based on patent cooperation data,this study used a range of city network analysis approaches in order to explore the structure of the Chinese city network which is driven by technological knowledge flows.The results revealed the spatial structure,composition structure,hierarchical structure,group structure,and control structure of Chinese city network,as well as its dynamic factors.The major findings are:1) the spatial pattern presents a diamond structure,in which Wuhan is the central city;2) although the invention patent knowledge network is the main part of the broader inter-city innovative cooperation network,it is weaker than the utility model patent;3) as the senior level cities,Beijing,Shanghai and the cities in the Zhujiang(Pearl) River Delta Region show a strong capability of both spreading and controlling technological knowledge;4) whilst a national technology alliance has preliminarily formed,regional alliances have not been adequately established;5) even though the cooperation level amongst weak connection cities is not high,such cities still play an important role in the network as a result of their location within ′structural holes′ in the network;and 6) the major driving forces facilitating inter-city technological cooperation are geographical proximity,hierarchical proximity and technological proximity.

Evaluation of Three-dimensional Urban Expansion: A Case Study of Yangzhou City, Jiangsu Province, China

With rapid urban development in China in the last two decades, the three-dimensional(3D) characteristic has been the main feature of urban morphology. However, the vast majority of researches of urban growth have focused on the planar area(two-dimensional(2D)) expansion. Few studies have been conducted from a 3D perspective. In this paper, the 3D urban expansion of the Yangzhou City, Jiangsu Province, China from 2003 to 2012 was evaluated based on Geographical Information System(GIS) tools and high-resolution remote sensing images. Four indices, namely weighted average height of buildings, volume of buildings, 3D expansion intensity and 3D fractal dimension are used to quantify the 3D urban expansion. The weighted average height of buildings and the volume of buildings are used to illustrate the temporal change of the 3D urban morphology, while the other two indices are used to calculate the expansion intensity and the fractal dimension of the 3D urban morphology. The results show that the spatial distribution of the high-rise buildings in Yangzhou has significantly spread and the utilization of the 3D space of Yangzhou has become more efficient and intensive. The methods proposed in this paper laid a foundation for a wide range of study of 3D urban morphology changes.

移动互联网时代碎片化学习的反思

在“互联网+教育”的积极作用下,移动互联网学习已经进入到人们的生活中。研究认为碎片化学习虽然具有学习内容的针对性、学习方式的灵活性、学习内容呈现的多彩性等特点,但碎片化学习造成了知识系统化的破坏、学习知识的浅表化、学习知识的纷繁芜杂,同时长时间的碎片化学习对学生的身心健康带来不利影响。从学习者、教育者和学习资源的承载体三个方面提出优化碎片化学习的策略。

粤港澳大湾区生态系统服务价值的时空演化及其影响机制

Ecosystem services are the media and channels through which ecological elements, structures, functions, and products benefit human society. Regulating the utilization intensity and protection methods of society on the ecosystem according to the ecosystem service value(ESV) and its influencing mechanism is of great significance for achieving the sustainable development goals. This paper takes the Guangdong-Hong Kong-Macao Greater Bay Area(GBA) as the research object and describes the spatiotemporal evolution characteristics of ESV in the GBA from 2000 to 2015. Panel quantile regression is also implemented to increase the understanding of the influencing mechanism of ESV. The main results are as follows:(1) From 2000 to 2015, the total ESV declined with a decreasing rate. The areas of decline were mainly distributed in the central part of the GBA and areas along the Pearl River Estuary.(2) Elasticity index, indicating response of ESV to land use change, reached its peak(1.08). The spatial distribution of elasticity index showed that land use changes brought about more intense ESV variations at the junction of cities.(3) In areas with different ESV levels, the influencing factors have different effects. Land use integrity can only promote ecosystem service capabilities in low-ESV areas. The positive effect of temperature on ecosystem service capacity increases with the increase of ESV, which reflects the self-reinforcement of the ecosystem. Moreover, the negative effect of economic density on ecosystem service capacity decreases with the increase of ESV, which reflects the self-protection of the ecosystem. The combination of such self-reinforcement and self-protection will lead to an ESV gap between the high-and low-ESV areas, and induce the “natural Matthew effect.”

区域贸易视角下中国省域隐含土地流动研究

With the continuous enhancement of regional connectivity,the indirect use of land resources through the pathways of trade in goods and services plays an increasingly important role in the overall utilization of land resources.Despite this,relevant research in this field is still in its infancy,and few papers have addressed this issue.This paper uses a multi-regional input–output model to calculate the embodied land in the 30 provinces(autonomous regions and municipalities)and eight regions of China from the perspective of regional trade and further analyzes the spatial pattern of characteristics associated with embodied land flows.The results show that the amount of embodied land occupied by China’s inter-regional trade accounts for 21.39%of the country’s total land,and an average of 38.54%of China’s provincial land demand is met by land exports from other provinces.More than 80%of land consumed by Beijing,Tianjin,and Shanghai is from other provinces.The provinces of Heilongjiang,Inner Mongolia,Xinjiang,and Hebei are the largest net exporters of cultivated land,forest and grazing and aquatic land,fishery land,and built-up land,respectively(the outflows account for 42.26%,27.53%,38.66%,and 35.28%of the corresponding land types in the province);and Guangdong,Shandong,and Zhejiang are the main net importers.The flow of agricultural land(cultivated land,forest land,grazing land,and aquatic land)generally shows a shift from west to east and from north to south.The regions in northeast and northwest China have the largest scale of agricultural land outflows,mainly into East and South China.In addition,8.43%of cultivated land,7.47%of forest land,6.41%of grazing land,6.88%of aquatic land,and 18.35%of built-up land in China are provided for foreign use through international trade.This paper provides feasible ideas and a theoretical basis for solving the contradiction between land use and ecological protection,which could potentially help to achieve sustainable land use in China.

Spatiotemporal evolution of urban carbon emission performance in China and prediction of future trends

Climate change resulting from CO_2 emissions has become an important global environmental issue in recent years.Improving carbon emission performance is one way to reduce carbon emissions.Although carbon emission performance has been discussed at the national and industrial levels,city-level studies are lacking due to the limited availability of statistics on energy consumption.In this study,based on city-level remote sensing data on carbon emissions in China from 1992–2013,we used the slacks-based measure of super-efficiency to evaluate urban carbon emission performance.The traditional Markov probability transfer matrix and spatial Markov probability transfer matrix were constructed to explore the spatiotemporal evolution of urban carbon emission performance in China for the first time and predict long-term trends in carbon emission performance.The results show that urban carbon emission performance in China steadily increased during the study period with some fluctuations.However,the overall level of carbon emission performance remains low,indicating great potential for improvements in energy conservation and emission reduction.The spatial pattern of urban carbon emission performance in China can be described as"high in the south and low in the north,"and significant differences in carbon emission performance were found between cities.The spatial Markov probabilistic transfer matrix results indicate that the transfer of carbon emission performance in Chinese cities is stable,resulting in a"club convergence"phenomenon.Furthermore,neighborhood backgrounds play an important role in the transfer between carbon emission performance types.Based on the prediction of long-term trends in carbon emission performance,carbon emission performance is expected to improve gradually over time.Therefore,China should continue to strengthen research and development aimed at improving urban carbon emission performance and achieving the national energy conservation and emission reduction goals.Meanwhile,neighboring cities with different neighborhood backgrounds should pursue cooperative economic strategies that balance economic growth,energy conservation,and emission reductions to realize low-carbon construction and sustainable development.

美国对伊朗石油禁运与全球能源安全

2018年6月美国针对伊朗启动了史上最严厉的石油禁运政策,要求所有国家于11月停止从伊朗进口石油,否则相关国家和企业都将面临美国的经济制裁,并无意给予任何国家豁免权。当前,中国、日本、韩国、印度和欧盟等世界重要的石油进口国已经做出回应,除中国明确拒绝美国的单边制裁继续保持与伊朗的石油贸易外,其他主要石油进口国都大量削减从伊朗的石油进口。沙特阿拉伯等石油生产国也承诺通过石油增产来维护全球能源市场的稳定,以支持美国对伊朗的制裁。在经济全球化的大趋势下,美国对伊朗的石油禁运,势必引发全球能源市场的动荡,改变全球石油政治格局以及相关利益方的石油权益。这些方面会涉及到全球油价的波动、不同国家的石油安全与应对政策、世界能源贸易稳定与地缘政治格局的变动等。长期关注能源地缘政治的专家学者围绕美国对伊朗的石油禁运可能产生的影响发表观点,专家们认为美国此举是战略两难的困境,短期内对将会引起世界石油短缺及油价波动,甚至可能导致OPEC减产协议崩溃,改变世界主要进口国的进口规模以及来源结构,但对世界石油市场的长期影响有限。伊朗将寻求打折出售原油、替代港口出口以及多元化出口3条生存路径,目前最大的隐患是伊朗或将封锁霍尔木兹海峡,但是此举目前可能性不大。伊朗石油禁运具有长期性和复杂性,对中国既是机遇也是挑战,中国在"一带一路"倡议下与伊朗保持正常的石油贸易是双赢的选择,但需要谨慎对待由此引发的能源地缘政治的风险,提升能源安全应对的措施。期待各方观点对伊朗石油禁运引发的能源地缘政治格局以及中国的能源安全的解析,能够为相关政策制定者提供理论借鉴。

胰腺内副脾伴表皮样囊肿误诊误治分析

目的探讨胰腺内副脾伴表皮样囊肿(ECIPAS)的影像学特征及误诊误治原因,以期提高术前诊断的准确率。方法收集2008年6月至2018年2月间浙江省人民医院经病理证实的8例ECIPAS患者临床及影像学资料。1例因体检发现血清CA19-9升高就诊,7例因体检发现胰腺占位就诊,均无明显症状。分析患者的C T和M RI影像学特征及诊治情况。结果8例ECIPAS患者病灶均位于胰腺尾部,呈囊实性,3例以囊性为主,囊壁呈线状,病灶影像学密度或信号及强化方式无法与脾脏对比;5例囊壁见实性成分,实性部分C T密度或M RI信号与脾脏相似,增强后动脉期实性部分均匀强化且强化程度高于胰腺,与脾脏类似,门静脉期均匀强化且与脾脏强化程度一致。8例患者术前均诊断为胰腺肿瘤而行手术治疗,1例术后出现胰瘘和胰周坏死物包裹。术后病理均证实为ECIPAS。结论通过提高放射科医师及临床医师对ECIPAS影像学表现的认知,可提高其术前诊断的准确率,避免因误诊而进行不必要的手术。

粤港澳大湾区生态系统服务价值的时空演化及其影响机制

生态系统服务是生态要素、结构、功能和产品造福于人类社会的媒介和通道。根据生态系统服务价值(ESV)及其影响机制调节人类社会对生态系统的利用强度和保护方式,对于实现人地和谐的可持续发展目标具有重要意义。本文以粤港澳大湾区作为研究对象,依托遥感数据修订ESV核算结果,更加准确地揭示2000—2015年粤港澳大湾区ESV的时空演变特征,并引入面板分位数回归深入探索生态系统服务影响因素的分段效应,增加对生态系统服务影响机制的认识。结果显示:(1)2000—2015年粤港澳大湾区ESV减速下降,下降区域主要分布在粤港澳大湾区中部和珠江入海口两岸等城市快速扩张区。(2)在城市交界处,土地利用变化会带来更为强烈的ESV变化。(3)在ESV水平不同的区域,影响因素具有不同的影响效果。用地完整度仅在ESV的低值区可以促进生态系统服务能力提升。气温对生态系统服务能力的正向作用随ESV的提高而增强,经济密度对生态系统服务能力的负向作用随ESV的提高而减弱,二者均会导致ESV高值区与低值区间的差距增大,形成"自然马太效应"。