极地微陨石的收集、研究与设想

微陨石对于人类研究地外环境和太阳系的演化而言,具有极其重要的意义。20世纪40年代开始,微陨石的收集便成了国际上的热点。尤其是80年代后,通过在南北两极开展微陨石收集,产出了大量的科学成果。我国的微陨石研究主要集中在20世纪80—90年代,而后便处于停滞的状态。本文简要介绍了各国在极地微陨石方面取得的成果,基于我国陨石和微陨石的研究现状,对我国开展极地微陨石研究提出了几点设想和规划。     

Spatial and temporal variation of the urban impervious surface and its driving forces in the central city of Harbin

Associated with the rapid economic development of China, the level of urbanization is becoming a serious concern. Harbin, the capital city of Heilongjiang Province, China and one of the political, economic, cultural, and transportation centers of the northeastern region of China, has experienced rapid urbanization recently. To examine the spatial patterns of long-term urbanization and explore its driving forces, we employed the impervious surface fraction derived from remote sensing image as a primary indicator. Specifically, urban impervious surface information for the central city of Harbin in 1984, 1993, 2002, and 2010 was extracted from Landsat Thematic Mapper image using a Linear Spectral Mixture Analysis (LMSA). Then, the spatial and temporal variation characteristics and the driving factors of percent impervious surface area (ISA) changes were analyzed throughout this 26-year period (1984 to 2010). Analysis of results suggests that: (1) ISAs in the central city of Harbin constantly increased, particularly from 1993 to 2010, a rapid urbanization period; (2) the gravity center of impervious surface area in the central city was located in Nangang District in 1984, moving southeast from 1984 to 1993, northwest from 1993 to 2002, and continuing toward the southeast from 2002 to 2010; and (3) the urban growth of the central city can be characterized as edge-type growth.     

基于POI数据的郑州市文化设施的区位布局特征与影响因素研究

以服务于居民的文化设施兴趣点为研究对象,采用标准差椭圆、核密度分析等方法,定量分析了2007年和2017年郑州市文化设施空间格局的演变,并从宏观的空间形态和微观的集聚中心2个方面对比分析了博物馆、图书馆、文化馆、美术馆、影剧院5类文化设施的区位布局特征;利用地理探测器,基于大规模实地调研数据引入居民行为因素探究对文化设施空间形态的影响,并针对郑州市文化设施规划发展的方向提出相关建议。研究表明：① 10 a来郑州市文化设施增长迅猛,由传统文化形式占优势转变为审美艺术和休闲文化占优势;② 不同类文化设施朝着均衡的方向发展;各类文化设施的集聚特征与其自身特点和城市实际发展情况相关。③ 居民可支配时间、消费习惯、居民文化水平等居民群体因素对文化设施分布的影响是不可忽视的,且不同因素对不同类文化设施的影响大小有较大差别。针对郑州市文化设施规划发展方向的建议：① 加强市区东北部和东南部文化设施建设;② 多注重审美艺术和休闲文化类设施的建设,迎合居民逐渐转变的精神与价值观趋向;③ 尝试文化设施的综合性布局和多用途开发;④ 在城市规划实践中综合考量不同居民群体对文化设施的需求程度和类型。     

陕西省气候的主成分分析与区划

P个气候要素、n个站点的气候要素场,由主成分分析,可用前m个主成分反映气候要素场的主要气候特征,由各主成分的空间分布,可以分析各地的气候特征。据此,将陕西省划分为5个气候亚带11个气候区。     

论“造山的高原”

地球上的高原依照其组成及形成过程差异分为两大类:克拉通高原与造山高原。克拉通高原是在古老的前寒武纪基底和稳定的克拉通的基础上构筑的高原,具有简单的、均一的、稳定的、冷的地壳以及刚性古老硬基底,如巴西高原、科罗拉多高原、埃塞俄比亚高原、南非高原、中西伯利亚高原和德干高原等。造山的高原是以造山单元作为主体的高原,分为俯冲型高原和碰撞型高原。前者如"中安第斯高原"与东太平洋的向东俯冲密切相关;后者如青藏高原,具有相对复杂、不均一、多地体拼贴、多期造山、相对热的巨厚地壳组成的造山软基底。研究表明青藏高原的初始高原在白垩纪形成,与班公湖-怒江缝合带的闭合(120~140Ma)有关。而印度-亚洲碰撞(60~50Ma)和印度岩石圈板片平俯冲在青藏高原之下,促使青藏高原整体的抬升至4000~5000m的高度。     

基于珠江三角洲ZK13孔年代和微体古生物重建的晚第四纪环境演化历史

依据珠江三角洲ZK13钻孔沉积物孢粉、微体古生物鉴定及年龄测试结果,将钻孔剖面记录的古环境信息划分为4个阶段。Ⅰ:91.50±11.00~84.61±5.47ka,孢粉组合为三缝孢-栎属-禾本科-栲属-松属-栗属-大戟科,反映温暖湿润气候,未见有孔虫及介形虫化石,沉积环境为陆相;Ⅱ:84.61±5.47~59.46±3.02ka,孢粉组合为栲属-三缝孢-栎属-禾本科-栗属-石竹科-单缝孢,反映干暖气候,未见有孔虫及介形虫化石,沉积环境为陆相;Ⅲ:59.46±3.02~2ka,孢粉浓度低,以孢子及木本植物花粉为主,进一步划分3个亚带,总体气候以温暖潮湿为主,微体古生物含量高,底栖有孔虫丰度远大于介形虫丰度,推测为海陆过渡相沉积环境;Ⅳ:2000~1000a,孢子含量最高,木本、草本植物花粉含量降低,气候较III阶段更湿润,微体古生物以介形虫为主,依据化石组合和数量,推测为海陆过渡相沉积环境。     

Influence of chlorine substitution on adsorption of gaseous chlorinated phenolics on multi-walled carbon nanotubes embedded in SiO<Subscript>2</Subscript>

Multi-walled carbon nanotubes (MWCNTs) embedded in SiO₂ particles were prepared through the floating-catalyst chemical vapor deposition method. The parameters reaction time and flow rate of the carbon source (CH₄) were studied to obtain optimum conditions for MWCNT synthesis. The obtained MWCNTs were characterized by transmission electron microscopy, scanning electron microscopy, Raman spectroscopy, and Fourier transform infrared spectroscopy to confirm their morphology and crystallinity. The optimum conditions were a CH₄ flow rate of 100 ml/min in a H₂–Ar mixture at a flow rate of 500 ml/min and a reaction time of 20 min. Under these conditions, MWCNTs with average outer and inner diameters of around 50 and 10 nm, respectively, were obtained. SiO₂ particles with embedded MWCNTs were studied for their adsorption of gaseous chlorinated phenolic compounds (CPCs), with emphasis on the effect of number of chlorine substituents. The CPC compounds of 2-chlorophenol (CP) and 2,4-dichlorophenol (DCP) were compared against phenol (P). Adsorption of P and CPCs on the particles fit well the Langmuir isotherm. The adsorption capacities of P, CP, and DCP on SiO₂ particles with embedded MWCNTs were found to be 3.12, 13.83, and 44.25 mg/g, respectively. Desorption activation energy was determined by thermogravimetric analysis. Chlorine substitution on P changed the adsorption process from physical to chemical adsorption. The particles showed high potential for use as a pre-concentration unit for solid-phase microextraction.     

黄海底栖纤毛虫的群落结构与时空变化

采用密度梯度离心结合定量蛋白银染色(Ludox-QPS)方法,对2010年7月和11月获自黄海海域沉积物中的底栖纤毛虫进行了群落结构研究,并结合环境因子进行了分析。结果表明:7月浒苔暴发期间,纤毛虫现存量以北黄海、南黄海近岸和长江口外海域较高,南黄海离岸站位较低;11月的纤毛虫丰度和生物量均明显高于7月,南黄海近岸站位的丰度和生物量较高,且向外海随水深增大呈减少的趋势。11月丰度和生物量前三位的类群与7月一致,前口类丰度所占比例最高,核残迹类生物量所占比例最高。肉食性纤毛虫均是两个月份的最优势摄食类群。11月纤毛虫的物种数、Margalef指数和香农-威纳指数均高于7月,且均以南黄海近岸海域较高,而离岸海域较低;纤毛虫丰度、生物量、物种数、Margalef和香农-威纳指数与底层水温度和沉积物中值粒径呈显著正相关。冷水团对底栖纤毛虫群落结构和分布有一定的影响,且是多个环境因子的共同影响。两个月份纤毛虫群落间的Jaccard相似系数值高于单个月份南北黄海和冷水团内外的系数值,表明黄海底栖纤毛虫的物种组成在季节间的差异可能小于不同海域之间的差异。7月南黄海近岸较高的纤毛虫现存量和多样性表明,浒苔的死亡和降解可能通过级联效应促进了近岸站位纤毛虫的生长。