Precipitation Chemistry and Corresponding Transport Patterns of Influencing Air Masses at Huangshan Mountain in East China

One hundred and ten samples of rainwater were collected for chemical analysis at the summit of Huangshan Mountain, a high-altitude site in East China, from July 2010 to June 2011. The volume-weighted-mean （VWM） pH for the whole sampling period was 5.03. SO2- and Ca2＋ were the most abundant anion and cation, respectively. The ionic concentrations varied monthly with the highest concentrations in winter/spring and the lowest in summer. Evident inter-correlations were found among most ions, indicating the common sources for some species and fully mixing characteristics of the alpine precipitation chemistry. The VWM ratio of [SO]-]/[NO3] was 2.54, suggesting the acidity of rainwater comes from both nitric and sulfuric acids. Compared with contemporary observations at other alpine continental sites in China, the precipitation at Huangshan Mountain was the least polluted, with the lowest ionic concentrations. Trajectories to Huangshan Mountain on rainy days could be classified into six groups. The rainwater with influencing air masses originating in Mongolia was the most polluted with limited effect. The emissions of Jiangxi, Anhui, Zhejiang and Jiangsu provinces had a strong influence on the overall rain chemistry at Huangshan Mountain. The rainwater with influencing air masses from Inner Mongolia was heavily polluted by anthropogenic pollutants.

Transport patterns and numerical simulation of heavy metal pollutants in soils of lead–zinc ore mines

Exploring transport patterns of soil contaminants is essential for solving the problem of heavy metal contamination in mine soils.In this study,contamination of Pb,Zn,and Cd in the mountain soils of the lead–zinc ore mines in Ganxi Township,Hengdong County,Hunan Province,China was investigated,and their transport patterns were further explored using a soil-column model and numerical simulation techniques.In total,111 mine soil samples were collected and placed into six experimental soil columns.By controlling the water flow,a control soil column group(CK),two mixed soil columns X1 with daily water flows of 1 and 5 L,and three mixed soil columns X3 with daily water flows of 2,3,and 4 L were evaluated.The results showed that the residual fraction of Pb accounted for 71.93%of the content on average,whereas the exchangeable fractions of Zn,Cd,and Fe-Mn oxide-bound fractions of Zn and Cd accounted for 28.60%,31.07%,and 43.2%and 53.54%of the content,respectively.Pb,Zn,and Cd in the soils of the CK,X1,and X3 groups mainly were accumulated at a depth from approximately 0 to 20 cm,and the content at this depth accounted for 60.09%of that at a 0~40 cm depth.The soil at a depth range of 0~10 cm was most seriously contaminated,and the proportion of content was 32.39%of that at a 0~40 cm depth.Numerical simulation showed that on the 5 th day,the pollutant transport range was 0~24 cm,and on the 9 th day,the pollutant transport range exceeded 40 cm.On the 15 th day,the transport capacity of pollutants at depths of 0~40 cm was close to the stable state,but the soil at a depth of 0~10 cm was still heavily polluted.These results reflect the transport pattern of heavy metal pollutants in the soil of lead–zinc ore mines and may provide a reliable scientific support for the prevention of heavy metal contamination in mine environments.

Transport patterns of micro nutrient elements from the continental shelf of the East China Sea to the Kuroshio area

On the basis of the in situ data of DO2, pH, SiO2. PO4-P, NO3-N and NO2-N collected in the north of the East China Sea during 1987-1988, the following points are mainly expounded.1.The inorgonic nutrients are obviously affected by continent runoff in the north of the East China Sea. Their distributions are characteristic of its distribution of terrigenous materials.2.There are three transport paths of nutrients from the shelf to the Kuroshio area. The first is mixing-diffusing-advec-tion and upwelling process, the process of biology and biochemistry belongs to the second, and the sinking process is the last one.3.The swing of the Kuroshio axis affectes both the range of the migration of substances through mixing-diffusing-advec-tion process and the upwelling degree of the subsurface Kuroshio water to the shelf.4.Most part of the substances sink as macroparticles to the deep layer before reaching the Kuroshio area.

The Sources and Transport Patterns of Modern Sediments in Hangzhou Bay: Evidence from Clay Minerals

Clay mineral compositions of 199 offshore surface sediment samples collected from the Hangzhou Bay have been analyzed. The clay minerals in the sediments from the Hangzhou Bay are dominated by illite(58.7%, on average), followed by chlorite(20.3%), kaolinite(16.9%) and smectite(4.1%). Two provinces were classified by Q-mode cluster analysis. Class Ⅰ with relatively low amounts of illite and smectite is widely distributed in the Hangzhou Bay, especially concentrated in the top and mouth of the bay, and the northern and southern nearshore areas. Class Ⅱ with comparatively high amounts of illite and smectite is mainly concentrated in the central part of the bay with the water depth of 8–10 m. By comparing clay mineral compositions with the neighbouring regions, we can find that the sediments in the Hangzhou Bay are mainly influenced by the resuspension and repeated deposition of particles from the Yangtze River due to the strong dynamic environment. In particular, the clay fraction of Class Ⅰ is mainly supplied by the Yangtze River, while the sediments of Class Ⅱ are mixture of the clay minerals carried by the Yangtze River and Qiantang River. In general, the distributions of clay minerals in the northern bay are affected by Yangtze River runoff, coastal current and flood tide together, and in the southern they are mainly affected by the Qiantang River runoff and ebb tide.

The Response of Anomalous Vertically Integrated Moisture Flux Patterns Related to Drought and Flood in Southern China to Sea Surface Temperature Anomaly

With the extreme drought(flood)event in southern China from July to August in 2022(1999)as the research object,based on the comprehensive diagnosis and composite analysis on the anomalous drought and flood years from July to August in 1961-2022,it is found that there are significant differences in the characteristics of the vertically integrated moisture flux(VIMF)anomaly circulation pattern and the VIMF convergence(VIMFC)anomaly in southern China in drought and flood years,and the VIMFC,a physical quantity,can be regarded as an indicative physical factor for the"strong signal"of drought and flood in southern China.Specifically,in drought years,the VIMF anomaly in southern China is an anticyclonic circulation pattern and the divergence characteristics of the VIMFC are prominent,while those are opposite in flood years.Based on the SST anomaly in the typical draught year of 2022 in southern China and the SST deviation distribution characteristics of abnormal draught and flood years from 1961 to 2022,five SST high impact areas(i.e.,the North Pacific Ocean,Northwest Pacific Ocean,Southwest Pacific Ocean,Indian Ocean,and East Pacific Ocean)are selected via the correlation analysis of VIMFC and the global SST in the preceding months(May and June)and in the study period(July and August)in 1961-2022,and their contributions to drought and flood in southern China are quantified.Our study reveals not only the persistent anomalous variation of SST in the Pacific and the Indian Ocean but also its impact on the pattern of moisture transport.Furthermore,it can be discovered from the positive and negative phase fitting of SST that the SST composite flow field in high impact areas can exhibit two types of anomalous moisture transport structures that are opposite to each other,namely an anticyclonic(cyclonic)circulation pattern anomaly in southern China and the coastal areas of east China.These two types of opposite anomalous moisture transport structures can not only drive the formation of drought(flood)in southern China but also exert its influence on the persistent development of the extreme weather.

Evaluation of Disparities between Transportation Needs and Trip Patterns of Men and Women in Kandahar City, Afghanistan

Consideration of gender equality in transportation planning is quite a new phenomenon. However, its significance is discussed widely by several researchers, particularly, in developing countries. In Kandahar city of Afghanistan, women have limited choices when it comes to using transportation services. With respect to some cultural, social, contextual, environmental, technological and physical barriers;women do not receive equal services from the current transport sectors. Using Revealed Preference and Stated Preference techniques, a survey was conducted in Kandahar city to identify the differences between trip patterns and transportation needs among men and women of the city. Our findings show distinct and clear disparities in socio-demographic characteristics of men and women of Kandahar city leading to trip disparities. Almost all of women do not own any types of personal vehicles, they are less educated and do not have jobs. Likewise, there is a considerable gap between trip characteristics and patterns of men and women. Majority of female trips are for educational purposes while male trips are more dispersed over multiple activities. Motorcycle is the most dominant and preferred mode for men, while women are mostly walking or using available public transit. Compared to men, women were recorded to have lesser trips per day over short distances. Transportation choices of women are also limited to walking, accompanying other male members of family or using public modes. However, men are generally using their private cars, motorcycles and bicycles together with all those options available for women. The results of Multinomial Logit Model showed that all selected variables such as vehicle ownership, income, travel cost and time will be significant factors for mode choice behavior of men, though for female respondents travel time and travel cost are main factors.

陆海交通连接工程对海岛区域景观格局时空演变的影响研究——以平潭综合试验区为例

陆岛联通工程是沟通陆域与岛屿地域的重要纽带,探明陆岛连接交通工程对海岛地区景观格局时空演变的影响,对维护海岛地区生态环境质量,实现可持续发展具有重要意义。以福建省平潭综合试验区作为研究区域,利用2017-2022年10 m分辨率土地数据,借助面板回归模型,探究大陆-海岛交通连接工程对海岛区域景观格局时空演变的影响。结果表明:(1)2017-2022年,平潭综合试验区景观格局整体呈现斑块间连通性趋好、景观集聚性越来越高,破碎化程度、景观多样性和异质性程度在不断减弱;(2)在空间方面,平潭岛内与海岛边缘景观格局指数变化差异显著,集聚度及破碎化趋势岛内高于边缘地带;(3)面板回归模型显示,公铁大桥建设对景观蔓延度存在显著负面影响,说明公铁大桥开通在短时间内导致海岛整体景观格局趋向于破碎化。

单层石墨烯微米尺度图案化和功能化:调控电子传输特性

石墨烯具有优异的物理特性,如单原子厚度、极高的载流子迁移率等。然而,其零带隙的半金属特性限制了题在高性能场效应晶体管中的应用。为此,研究者们提出了石墨烯纳米化、外场诱导、掺杂以及化学图案化等策略,以调控其带隙宽度。但是,这些方法的可控性以及稳定性还需要进一步改善。在本研究中,我们提出采用电化学溴化并结合光刻图案化调控单层石墨烯的电子传输特性,通过这种方法,成功制备了图案化的溴化石墨烯(SLGBr)。进一步研究表明,单层石墨烯的电子传输性能可以通过溴化程度来调控。当溴化程度较小时,SLGBr表现为电阻特性,且其电导随溴化程度增加而减小;当溴化程度增加到一定值时,SLGBr表现为与半导体类似的特性。本研究将为全石墨烯器件的制备提供可行的技术路线,拓展其在微电子领域的应用。

少断裂深水油气成藏模式与有利区优选——以圭亚那盆地上白垩统为例

为明确少断裂深水油气运移机理与成藏富集模式,以圭亚那盆地上白垩统为对象,利用地震、测井、钻井及烃源岩测试分析等资料,研究盆地上白垩统石油地质特征,明确研究区成藏模式,划分勘探有利区。结果表明:烃源岩为土伦阶—康尼亚克阶沉积的巨厚黑色页岩,TOC质量分数为4%~7%,有机质类型以Ⅰ、Ⅱ型为主;储层为坎潘阶—马斯特里赫特阶水道、堤岸、朵叶亚相砂岩;主要盖层为古近纪早期沉积的泥岩与物性较差的巨厚粉砂岩。盆地陆坡区发育砂体叠置—断层斜向型运移体系,形成“源—储紧邻、断—砂匹配、水道聚集”的成藏模式;深水区发育砂体叠置—裂缝垂向型运移体系,形成“源—储分离、缝—砂匹配、高点聚集”的成藏模式。盆地中心深水区烃源岩发育与水道发育叠合区为勘探首选目标,北部堤岸发育与烃源岩发育叠合区或未与烃源岩重合的水道发育地区为勘探的第二选择。该结果对相似地质条件的盆地勘探具有指导意义。

福建省沿海港口货运职能识别及结构演变研究

精准识别港口货运职能及其演变规律,是推动港口群协同发展的重要环节。采用货种区位商、货物离散指数、港口分工系数等方法,定量分析福建省沿海港口群货物吞吐量增长态势、货运职能及结构演变趋势。结果表明:2000—2020年,福建省沿海港口群货物吞吐量整体呈增长趋势,但年增长速度趋于放缓;沿海港口群的主要职能以煤炭、钢铁、粮食等传统货物运输为主,其中福州港主要职能最多,具有一定的综合功能;沿海港口群的港口分工系数明显下降,各港间货种结构差异缩小,货运职能特征由单一向多样化转变。今后应优化福建省沿海港口群空间布局,明确港口功能定位,促进沿海港口协同发展。

汉江流域夏季降水演变的水汽输送驱动机制

为应对气候变化下愈加频繁和剧烈的干旱事件,保障跨流域调水工程水源及当地用水安全,亟需对汉江流域这一国家重要战略水源地的降水过程变化进行研究。汉江流域夏季降水占全年降水的40%~50%。本研究利用拉格朗日混合单粒子轨道模型对汉江流域1959—2022年夏季降水的水汽输送过程及其大气环流背景进行分析,以揭示汉江流域夏季降水变化的原因。研究发现,历时72 h以上降水占夏季总雨量的44.6%,在过去半个多世纪中其频次和雨量均呈现显著下降趋势,是汉江流域降水减少的主要原因。对水汽输送过程的模拟分析表明,中国南海、西太平洋、中国东部是流域夏季降水的水汽来源,贡献率分别为:34.7%、28.7%、27.2%。对比不同历时降水的水汽输送过程,发现降水历时越长,来自中国南海和西太平洋的水汽贡献率越高。尽管来自西太平洋的水汽呈现显著增加,但来自中国南海的水汽显著下降,使得72 h以上降水仍然呈现下降趋势。分析大尺度气候指数与各水汽输送路径贡献率的相关性,发现中国南海水汽贡献减小与西太平洋副热带高压面积、强度增加呈显著负相关。这证实了近年来西太副高的增强和扩张对汉江流域夏季降水减少起到促进作用。

微通道换热器拓扑结构优化与性能研究

换热器结构拓扑优化可将传热强化设计问题转化为数学优化问题进行求解,对于设计新颖高效换热器具有重要价值。然而,拓扑优化数学模型难以直接解释优化结果的几何特征及相应强化机理。以传热量为目标,对微通道换热器进行拓扑优化设计,研究了不同参数对换热器强化结构特征和换热器性能的影响。结果表明,拓扑优化换热器的通道结构呈现多级分叉构型,分叉的数量随着入口Reynolds数、翅片传热效率和流体Prandtl数的增大而增多。在此基础上,采用耗散和边界层理论分析了拓扑优化分叉通道与流体边界层厚度的内在联系,为换热器结构强化设计提供了新的思路。

缢蛏ABC转运蛋白基因家族成员全基因组鉴定及表达模式分析

腺苷三磷酸结合盒转运蛋白(ATP binding cassette transporter,ABC transporter)家族是最古老的膜蛋白家族之一,广泛存在于原核生物和真核生物体内,利用ATP水解释放的能量对氨基酸、脂质、抗生素等物质进行跨膜运输,参与生物体内多种生理活动。目前,对软体动物ABC转运蛋白家族的鉴定,仅在虾夷扇贝(Patinopecten yessoensis)、栉孔扇贝(Chlamys farreri)和长牡蛎(Crassostrea gigas)3种双壳类中有系统研究,对缢蛏(Sinonovacula constricta)ABC转运蛋白家族的鉴定和表达模式分析尚未见报道。利用缢蛏基因组和转录组数据,运用本地及NCBI在线BLAST程序、FGENESH+、SMART、Ex PASy、MEGA X、Mev 4.90和MapInspect等生物信息学分析工具,在全基因组水平系统地鉴定出52个缢蛏ABC转运蛋白,并对转运蛋白基因外显子数目、染色体定位等信息进行分析;通过系统进化分析,将缢蛏ABC转运蛋白家族分为8个亚家族,即ABCA~ABCH;通过比较分析不同物种ABC转运蛋白家族,推测基因串联复制事件对软体动物ABC转运蛋白家族成员数目的增加有影响。ABC转运蛋白基因在缢蛏不同发育时期和组织的表达分析显示,ABCC和ABCG亚家族多个基因在缢蛏稚贝时期表达量达到最高值,ABC转运蛋白基因在鳃、肝胰腺和性腺中表达种类较多。软体动物作为第二大动物类群,目前仅有3个物种的ABC转运蛋白得到了系统分类,缢蛏ABC转运蛋白基因家族的系统鉴定与表达模式分析为研究软体动物ABC转运蛋白基因的进化和缢蛏ABC转运蛋白功能提供了基础资料。

甘肃省铁路网高质量发展规划研究

为推动甘肃省铁路网现代化建设和综合交通高质量发展,立足新发展格局下甘肃省铁路发展现状和形势要求,对甘肃省铁路网规划布局进行系统研究。首先,对目前甘肃省铁路网布局结构、路网规模水平、运输效率、运输能力适应性等进行研究,剖析甘肃省铁路网发展存在的瓶颈弱项;其次,基于甘肃省铁路客货运输需求,以问题破解、需求支撑、发展引领为导向,提出甘肃省铁路网发展思路、发展目标和布局方案。研究表明,甘肃省将形成“一心两廊多放射”的铁路网格局,构建“1259小时交通圈”,实现区域内部市市通高速铁路、区域对外多径路快速通达、货运体系保障有力。

基于城市公共交通可达性的医疗服务空间评价——以成都市金牛区为例

医疗服务可达性是城市居民就医便利程度的重要影响因素。利用ArcGIS网络分析模式与空间点格局分析法评估成都市金牛区医院与居住区的空间分布特征及就医平均可达时间,讨论私家车与公交车关于可达性水平的高低与空间聚集现状。研究结果表明,金牛区医院整体可达性较强,91.26%的居住区基本满足30 min的就医需求,顶峰时段公共交通工具更具优势。金牛区的医疗服务设施等资源存在8.3%的重叠及分配不均现象,可对相应医院的设施及配置进行优化,提升各医院的基础服务水平,扩大服务范围,开通快速直达道路,避免因交通拥堵而造成不必要损失。金牛区的居住区与医院分布方向大致相同,圈层密度由核心到边缘逐渐减少,但密度较低区域部分居民就医需求无法得到满足。应优化可达性较弱居住区周边的公共交通基础设施,更深层次维护多种公共交通间的联系。

基于夜光遥感的我国春运人口流动时空特征研究

基于2013、2019和2021年的NPP/VIIRS夜间灯光数据,构建春节夜光差值指数,在省域尺度上证明了差值指数与流动人口量具有显著相关性(R=0.61,P<0.01),并以该指数研究了全国春运期间人口流动的时空特征。结果发现:1)我国春运强度在胡焕庸线两侧差异明显,东南地区人口流动是西北地区的6倍左右。春运在东南地区呈现连片式特征,在西北地区呈现离散零星式的流动特征。2)2013—2021年间,我国春运期间总体人口流动格局大致稳定,但流入地和流出地在空间上存在一定变化。3)经济发展状况和新冠疫情可能导致了这种格局演化特征的发生。尤其新冠疫情防疫和“就地过年”政策的推出,导致2021年春节期间大规模人口流动的减少,春运强度的下降。

交通信息化对中国“一带一路”沿线省域交通碳排放影响的时空分异格局

选取中国“一带一路”沿线17个省级行政单位作为基本空间单元,建立2012~2022年“一带一路”交通信息化评价指标体系,采用双变量空间相关性分析交通信息化与交通碳排放之间的相关关系,使用地理探测器来研究交通信息化对交通碳排放影响的时空异质性.结果表明,“一带一路”沿线省域的交通信息化发展水平不一,对外窗口区和开放先行区的交通信息化发展较为成熟,丝路核心区和战略支点区的交通信息化发展相对较落后;双变量空间自相关指数为0.1917~0.4001,整体呈下降趋势,显著性水平介于0.008~0.060,高-高集聚主要分布在开放先行区,低-低集聚主要分布在丝路核心区,高-低集聚主要分布在对外窗口区和战略支点区,且分布在高-低集聚的省域逐年增多;交通信息化系统应用是影响“一带一路”沿线整体交通碳排放空间分异格局的主导驱动因子,其决定力均值最大达0.53,不同省域间影响交通碳排放空间分异的驱动因子存在差异,且驱动因素之间存在较强的协同性.

广西壮族自治区春节假期城际交通需求分析

运用2024年广西壮族自治区内收费站数据分析广西壮族自治区2024年春节假期城际交通需求特征。对城际交通需求的时间空间特性进行分析,了解2024年春节假期期间城际交通的时间空间变化趋势;利用奇异值分解降维算法对城际客流的时空OD矩阵进行降维分解,降维后识别出3种典型的交通需求模式。研究结果表明,2024年春节假期交通需求分为3个模式:日常城际交通需求模式、假期返乡交通需求模式和假期后返城复工复学交通需求模式。对于日常城际交通需求模式,整体交通需求呈稳定趋势;对于假期返乡交通需求模式,春运开始后到春节假期结束前城际交通需求有了明显的增长,但南宁市、桂林市等经济较为发达的城市呈现出负向需求;对于假期后返城复工复学交通需求模式,在春节前几日达到需求最小点,在法定假期结束后的第1天达到需求最大值。该分析为广西壮族自治区应对未来年春节假期的交通需求的变化提供了依据。

基于公交数据融合的城市人群移动模式识别——以重庆市中心城区为例

揭示城市人群移动模式对理解人群移动行为、优化城市空间结构和解决交通问题具有重要意义。针对传统问卷方式存在数据量少、准确性差、实时性不足等问题,该文融合公交刷卡、公交GPS、公交线路和轨道交通刷卡数据,提出一种数据驱动的城市人群移动模式识别方法。首先,对多源公交数据进行匹配融合,提取公交、地铁联运的城市人群移动OD,再进行稳定居住地和稳定工作地识别,最后以稳定职住地匹配判别出行语义,识别居民通勤、购物、聚餐等社会活动出行模式。利用重庆市中心城区连续1周的公交数据进行验证,实验结果显示:①重庆市中心城区人群出行主要集中在工作日,且出行人数随出行频率的增加而降低;②79.34%的人群出行呈现“两点一线”移动模式,呈现三点、四点和多点移动模式的人群出行占比分别为13.03%、5.99%和1.64%。该文方法可以更全面精细地识别城市人群移动模式,有助于城市管理者、规划者了解城市人群移动方向,优化城市资源配置。