地表糙度是衡量地表径流形成的一个重要指标.以东北区典型泥炭沼泽—金川泥炭沼泽为例,考虑地表坡度影响,用链条法对不同群落中糙度系数指标进行计算,并以泥炭沼泽中物种多样性、踏头个数以及踏头形态差异变率系数为主,初步分析泥炭泥泽地表糙度的变化机制,结果表明:在芦苇-臌囊苔草群落、臌囊苔草群落和油桦-臌囊苔草-泥炭藓群落三个植物群落中,糙度系数指标的变化与群落中物种丰富度和生物多样性变化相一致;糙度系数变化与踏头个数呈负相关关系,与踏头形态差异变率系数呈正相关关系.说明物种多样性越小,生态优势度越大,优势种植物越少,踏头个数越多,踏头形态变率系数越小,微地貌形态发育相对较一致,糙度系数越小;反之,则地表糙度系数越大.;Surface roughness was an important indicator for the formation of surface runoff. This paper takes peat mire of Northeast Jinchuan peat mire as an example, considering impacts of surface slope to measure the roughness index with the chain method in different plant communities. Based on the plant richness, the number of hummock and the coefficient of variation of the hummock forms, we analyzed the mechanism of the changes of surface roughness. The results showed: in three Phragmites australis-Carex schmidtii community, Carex schmidtii community and Betula ovilifolia-Carex schmidtii-Sphagnum palustre community, roughness coefficients changed consistently with changes of species richness and biodiversity of the communities. The changes of the roughness were negatively correlated with number of the hummocks, and positively correlated with coefficient of variation of the hummock forms. It showed that, the smaller the species richness, the larger the ecological dominance;the fewer the dominant plant, the more the number of the hummocks;and the smaller the coefficient of variation of the hummock forms, the more consistence the forming of the micro-geomorphologic relief and the smaller the roughness coefficient. Otherwise, the roughness coefficient became bigger.
Quantifying turbidity source is essential but complex for precise environmental rehabilitation of worldwide urban lakeside river networks impaired by turbidity. A new turbidity source analysis framework including in-situ sampling, vessel monitoring, remote sensing, and MIKE 11-based simulation was proposed, where the critical processes of flow reversal from turbid lake, navigation, and urban non-point source in urban lakeside river networks were explicitly considered. The case study results showed that turbidity problem was primarily led by suspended inorganic matter (58%), followed by suspended organic matter (19%) and other matter. The Tiaoxi River and busy shipping contributed most to annual total suspended solids (TSS) load of target river, with the same percentage of 34%. The turbid Lake Taihu provided 31% of total TSS load, focusing on autumn and winter months. Tiaoxi River load was highly concentrated on the storm events, which accounted for 71.4% of annual Tiaoxi River source. Coronavirus disease (COVID-19) lockdown and Spring Festival holiday has a significant effect on the change of shipping and Tiaoxi River sources, through limiting the waterway transportation and the market demand for building materials. River estuary’s vegetation interception belt, shipping restriction and rerouting and integrated catchment management were advised to mitigate the urban river network turbidity.
确定河流鱼类群落的时空分布格局及其形成机制是开展鱼类物种多样性保护与管理的科学基础.基于2013年10月和2014年5月共2次对太湖流域57个河道样点的调查数据，初步研究太湖流域河流鱼类群落结构及其多样性的季节动态和空间分布特点.共采集鱼类5051尾，计46种，其中鲤科鱼类26种，占全部物种数的57%.10月份的鱼类多样性显著高于5月份，且2个季度的鱼类群落结构存在显著性差异.5个主要水系间的鱼类多样性差异显著，总体上，沿江水系和洮滆水系鱼类多样性较低，黄浦江水系居中，而南河水系和苕溪水系较高；鱼类群落结构也随水系而显著变化，主要表现为黄浦江水系与洮滆、苕溪和沿江水系呈显著差异.在2个一级生态分区之间，鱼类多样性无显著差异但群落结构显著不同，主要因、鲫、似鳊等优势种及宽鳍鱲、尖头鱥、中华青鳉、食蚊鱼等偶见种的空间分布差异所引起；在4个二级生态分区之间，鱼类多样性和群落结构均存在显著的空间变化.;Identifying the distribution of species composition and their abundance of fishes is basic for the conservation and management of fish diversity. Based on the data collected from 57 stream segments within the Taihu Lake Basin during October 2013 and May 2014, we examined how the stream fish assemblages vary spatially and seasonally in this study area. A total of 5051 individuals representing 46 species were collected, among which Cyprinidae fishes are amounted to 26 species. Fish diversity in October was significantly higher than that in May, and fish assemblage structures also significantly differed seasonally. Significant variations among different subbasins were observed for both fish species diversity and assemblage structures. The Yanjiang and Zhaoge subbasins had relatively lower species diversity, while those in the Nanhe and Tiaoxi subbasins were relatively higher. Assemblage structures in the Huangpujiang subbasin showed significantly difference from those in the Zhaoge, Tiaoxi and Yanjiang subbasins. When the spatial variations in fish assemblages among ecoregions were considered, fish assemblage structures, not species diversity, showed significantly variation between two ecoregions at level-1; while both assemblage structures and species diversity differed significantly among four ecoregions at level-2. This among-ecoregion variations in assemblage structures resulted from the spatial distribution of some dominant fishes, such as Hemiculter leucisculus, Carassius auratus and Pseudobrama simoni, and some rare fishes, such as Zacco platypus, Phoxinus oxycephalus, Oryzias latipes sinensis and Gambusia affinis.
Magnetic Fe<sub>3</sub>O<sub>4</sub> nanoparticles show promising applications in nanomedicine. The saturation magnetization (<i>M</i><sub>S</sub>) and magnetic anisotropy are critical for the applications of Fe<sub>3</sub>O<sub>4</sub> nanoparticles in drug delivery and magnetic hyperthermia. Here, by density functional computation, the doping effects of 3d and 4d transition metal elements (including Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag and Cd) on the magnetic properties of Fe<sub>3</sub>O<sub>4</sub> are investigated in-depth. A conventional cell of Fe<sub>3</sub>O<sub>4</sub>, containing 24 Fe atoms and 32 O atoms, has been used to investigate the doping of group III elements. One 3d or 4d atom is doped in one conventional cell of Fe<sub>3</sub>O<sub>4</sub>, resulting in the formation of X<sub>0.125</sub>Fe<sub>2.875</sub>O<sub>4</sub> where X represents the dopant. The results show that the doping of most 3d and 4d transition metal elements will reduce the total magnetic moment, while the doping of Ag, Zn and Cd in Fe<sub>3</sub>O<sub>4</sub> will increase the total magnetic moment by 19%–22%. However, it is hard to dope Ag into Fe<sub>3</sub>O<sub>4</sub> according to the positive formation energy. Therefore, Zn and Cd are good candidates to improve the <i>M</i><sub>S</sub> of Fe<sub>3</sub>O<sub>4</sub>. The doping of Zn and Cd has also an influence on the magnetic anisotropy of Fe<sub>3</sub>O<sub>4</sub>. For Zn<sub>0.125</sub>Fe<sub>2.875</sub>O<sub>4</sub>, the magnetic anisotropy energy is about 0.25 meV per cell, which is slightly larger than that of intrinsic Fe<sub>3</sub>O<sub>4</sub> (0.2 meV per cell). Interestingly, the doping of Cd (Cd<sub>0.125</sub>Fe<sub>2.875</sub>O<sub>4</sub>) will greatly increase the magnetic anisotropy energy to 0.8 meV per cell, which is significant for the specific absorption rate in the magnetic hyperthermia application. In addition, the doping of Zn and Cd will not induce any defect states in the band gap according to the density of states. Zn<sub>0.125</sub>Fe<sub>2.875</sub>O<sub>4</sub> and Cd<sub>0.125</sub>Fe<sub>2.875</sub>O<sub>4</sub> are both semiconducting and both the top of valence band and the bottom of conduction band originate from octahedral Fe. This is because the impurity states are very deep in energy. Our research results show that doping Cd is a feasible way to improve the performance of Fe<sub>3</sub>O<sub>4</sub> as a material for drug delivery and magnetic hyperthermia.
Ecological function division was a foundation of ecosystem service function research,ecosystem heterogeneity and change study and countermeasures for ecological restoration.In the paper,based on ecological environment condition analysis,satellite imagery and forest management inventory(FMI),by means of ARCGIS layer overlay functions and methods,three ecological areas and six ecological function areas were produced.In addition,according to main ecological problems of different ecological areas,ecological protection and construction countermeasures were put forward.
Geological conditions for ore-forming are relatively good in Laiwu city.There are rich mineral resources in this area.At present,42 kinds of minerals have been found,and 18 kinds of mineral resources have been proved reserves.In recent years,Laiwu city makes great efforts to manage exploration order of mineral resources,and mining development work has been standardized as well.
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