Subjects: Geosciences >> Geography submitted time 2023-12-16 Cooperative journals: 《干旱区研究》
Abstract： Understanding the species diversity of submerged plant communities in response to nitrogen and phosphorus nutrition levels in sediments can clarify the relationship between the two. This relationship has direct theoretical and practical significance for studying the spatial and temporal changes of wetland vegetation and environment, and has implications for habitat restoration, pollution control, and planning management in the study area and similar areas. In this study, the wetland areas (lakes and ditches) of Yinchuan Plain were used as the research area to conduct a field survey of the submerged plant communities to obtain an understanding of the environmental sediment nutrients. Three typical submerged plant communities were screened out by the community classification method, and the nitrogen and phosphorus nutrient levels of the wetland sediment were evaluated. A structural equation model was used to analyze the relationship between the species diversity of typical submerged plant communities and the nitrogen and phosphorus nutrient components of the sediments. The results revealed that eight common submerged plants exist in the wetlands of Yinchuan Plain. The typical submerged plant communities were identified as a Potamogeton pectinatus community, a Myriophyllum spicatum community, and a Potamogeton crispus community. The species composition diversity and species contribution of the Potamogeton crispus community were high, and the species distribution was uniform. The species in the Potamogeton pectinatus community showed cluster or patchy distribution. Three levels (rich, moderate, and poor) of nitrogen and phosphorus fertility were identified in the sediment of the wetlands of Yinchuan Plain, and moderate and poor levels of fertility were most commonly found. The Potamogeton pectinatus and Myriophyllum spicatum communities were found to grow mainly in the poor- and moderate-level fertility sediment areas, while the Potamogeton crispus community was found to grow in all three levels of sediment nutrient content. The nitrogen and phosphorus nutrition level of the sediment had a significant positive effect on the three typical submerged plant communities, promoting an increase in the community diversity index. The characteristics of the three typical submerged plant communities were mainly affected by species evenness. The nitrogen and phosphorus fertility level of the sediment was mainly affected by the phosphorus level in the sediment.
Subjects: Geosciences >> Geography submitted time 2020-12-17 Cooperative journals: 《干旱区研究》
Abstract：内蒙古托克托县地下水普遍高氟、高盐，大部分不适合长期饮用，而位于县城西南的“神泉”，却因优良的水质成为该区域人民生活的主要水源。为了探寻“神泉”水的来源及其与周边地下水化学特征不同的原因，通过收集水文地质资料、实地踏勘及取样分析的基础上，利用Piper三线图法、Durov图法、地下水流动系统分析等方法对该泉水以及周边地下水进行对比分析并追溯其来源。结果表明：（1）“神泉”虽处于托克托县境内冲湖积平原排泄区并紧邻黄河，但其水质低氟高锶（HCO3-Ca型水）与黄河水（Cl-Na型水）及周边地下水（高氟、高TDS）有本质的不同。（2）“神泉”水与黄河水及周边地下水无明显的水力联系，其主要是由库布齐沙漠区地下水通过鄂尔多斯北缘断层，经由黄河河床淤泥下伏断裂通道补给形成，属于典型的断层泉。
Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract： The production and measurement system of uniform axial hypomagnetic field based on Silicon Labs C8051F005 micro-processor is designed for the research on biological effects of the hypomagnetic field. A new structure for producing uniform axial hypomagnetic field is suggested according to the principle of magnetic field generated by Helmholtz coil. MAX038 is used for hardware circuit to generate the alternating magnetic field. The magnetic field can be accurately measured by magnetoresistive sensor, the data of which are transferred to the host computer via serial port, and then displayed graphically in real time. The uniformity of the magnetic field generated with the new structure is experimentally demonstrated to be better than that generated with Helmholtz coil. Experiments show that the magnetic field intensity is proportional to the current, and has the well controllability. The frequency of alternating magnetic field can be controlled by simple parameter setting.
Peer Review Status:
Awaiting Review
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