Search

【Objective】 Discharge coefficient is a coefficient describing the discharge of non-point source pollution to water bodies. It is affected by many biotic and abiotic factors. In this paper, we analyze its variation in typical drylands in river network areas in a plain. 【Method】 The studied area is located at the Chongming Island, Shanghai. A hydrology-water quality collaborative monitoring system was constructed in the island, which can accurately calculate the discharge coefficient of non-point source pollution, identify its temporal variation, and analyze the underlying influencing factors. 【Result】 ① Daily discharge coefficient of total nitrogen (TN) and total phosphorus (TP) is 2.2-9 843.9 and 0.08-667.0 g/(hm2·d), respectively; monthly discharge coefficients of TN and TP is 0.02-17.2 and 0.001-1.04 kg/(hm2·m) respectively. ② The total nitrogen discharge coefficient during precipitation runoff period is significantly positively correlated with duration of the precipitation, while the TP discharge coefficient is significantly positively correlated with the total precipitation, average precipitation intensity, and maximum hourly precipitation intensity. ③ Following fertilization, the daily discharge coefficient of TN increases rapidly, while the daily discharge coefficient of TP remains almost unchanged. ④ At different time scales, there is no notable correlation between TN discharge coefficient and surface runoff, whereas the TP discharge coefficient exhibits a significant positive correlation with surface runoff. 【Conclusion】 The discharge coefficients of nitrogen and phosphorus vary with time scales, with significant differences observed between daily and monthly discharge coefficients. TN discharge coefficient is primarily influenced by fertilization, whereas TP discharge coefficient is more sensitive to precipitation and surface runoff.

Aiming at the problems that the penalty factor and kernel function parameters of SVM（support vector machine） are easy to fall into the local optimal solution in the optimization process and the Harris Hawks optimization algorithm is easy to fall into the local optimal solution， a method of using IHHO （improved Harris Hawks optimization） algorithm to optimize the penalty factor and kernel function parameters of SVM and constructing IHHO-SVM classifier to identify disturbance signals of power quality is proposed. By adding 0 dB，20 dB and 30 dB Gaussian white noises to nine different disturbance signals of power quality， the improved empirical mode decomposition algorithm of adaptive noise complete set is used to decompose the signal， and the energy entropy and sample entropy of the first three intrinsic mode function components of the signal are extracted as a set of feature vectors. The feature vectors are normalized and input into nine classifiers for comparison. The simulation results show that the recognition accuracy of IHHO-SVM classifier is 99.11%， 97.78% and 97.33%， respectively， when the signal is added with 0 dB，20 dB and 30 dB Gaussian white noises. The classification effect of IHHO-SVM classifier is the best among all classifiers， which proves the accuracy， superiority and noise immunity of its classification.

Objective To explore the biological effects of electromagnetic pulse (EMP) with different high intensities on condylar cartilage in rats. Methods SD rats were randomly divided into a sham group (Sham) and an irradiation group (EMP1: 500 kV/m, 10 Hz; EMP2: 270 kV/m, 10 Hz). Then, they were sacrificed at 1 h, 3 h, 12 h, 24 h and 3 d after irradiation. The degree of cartilage degeneration was evaluated by HE, safranine O-fast green, type Ⅱ collagen immunohistochemistry and TUNEL staining. Immunohistochemistry and western blot were performed to detect the expression of the matrix degradation factors: matrix metalloproteinase-13 (MMP-13), a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS-5) and the apoptosis key factor cleaved-cysteinyl aspartate specific proteinase (cleaved-Caspase3) in condylar cartilage. Results HE staining showed that, compared with the Sham group, a small amount of exfoliation was found on the fibrous surface layer of the cartilage after irradiation in the EMP1 and EMP2 groups. Compared with the Sham group, the percentage of safranine O-fast green-positive area decreased significantly at 12 h and 24 h (both P

Zr is one of the most deeply investigated and widely used microalloying elements. The low diffusivity of Zr and the formation of thermal-stable Al3Zr dispersoids with the properties of low density, high melting temperature and low interface misfit in Al matrix, making Zr owing a broad prospect of application in developing heat-resistant Al alloys. However, strengthening by Al3Zr has been limited by either low number density or low volume fraction. In addition, the interaction among multiple components is very complex in multi-component Al alloys during solidification, deformation and heat treatment, and it is very difficult to achieve a good combination in strengthening of Al3Zr with the intrinsic phase of each system. In this review, the existing form, the precipitation and coarsening behavior, and the strengthening mechanism of Zr element in Zr-containing Al alloys were summarized. The mechanism of complex microalloying with multiple elements on promoting Al3Zr dispersion was briefly introduced. Finally, the effects of Zr addition on several series of Al-based alloys were summarized. In sum, microalloying with Zr is of great significance for regulating microstructure and improving room temperature/high temperature strength in Al alloys.

Traditional villages are the best witness of the process of agriculture civilization, with rich material and intangible culture heritage. However, under the influence of rapid urbanization, industrialization and globalization, the development of traditional villages is faced with dilemmas such as the decline of material space, the inactivation of cultural space and the hollowing of social space. Scientifically guiding the function renewal and spatial adaptive transformation of traditional villages is not only the practical needs of their protection and development, but also an important topic of rural development and planning research in China. Taking the national traditional village Maihuayucun Village in Huangshan City as an example, on the basis of field investigation, combined with the relevant literature review, and based on the perspective of "ternary dialectics" of space production, this paper analyzes the spatial transformation process, characteristics and driving mechanism of traditional villages from the three dimensions of material space, social space and institutional space. The results show that: (1) Since the reform and opening up, Maihuayucun Village has gradually evolved from a traditional agricultural village to an industrial village characterized with bonsai industry, which has experienced three stages: endogenous slow transformation and development, exogenous space rapid expansion and orderly space quality improvement. (2) The spatial transformation of traditional villages is characterized by the functional differentiation and remodeling of material space, the disintegration and reconstruction of social space, and the gradual improvement of institutional space. The space function has gradually changed from the traditional production and living function to multiple composite functions such as ecological leisure, characteristic bonsai planting, commercial operation and service, and cultural inheritance and display. The livelihood of villagers has been diversified, from the traditional single agricultural planting industry to the diversified livelihood methods such as bonsai management, farmhouse entertainment, and tourism services, and the social relations have changed from closed tradition to open and modern. And the subject of institutional space has changed from the dual subject of village committee and villagers to the multiple subject of government, village committee, villagers, capital and tourists. (3) The changes of social relations, capital investment and power intervention are the main driving forces for the spatial production of Maihuayucun Village. The three forces interact and promote the interactive evolution of social space, material space and institutional space, and jointly promote the spatial transformation. With the disintegration of traditional agricultural economy and the growth of bonsai industry, the growing demand for production and residence of villagers has promoted the continuous expansion and transformation of village material space. Driven by bonsai industry and rural tourism, the exogenous construction of villages has developed rapidly, and the support of a large amount of external capital has provided a strong driving force for the spatial transformation of villages. A series of rural development policies and measures issued by the state, especially the implementation of the rural revitalization strategy, provide strategic guidance and policy guarantee for the protection, development and spatial transformation of traditional villages. In the context of rural revitalization and integrated rural and urban development in the new era, and the increasingly complex relationship between man and land in rural areas, it is particularly important to explore the differentiated and distinctive path of China's rural transformation and development. And the research on the temporal and spatial characteristics and mechanism of rural spatial transformation of different types and different spatial scales needs to be further broken through. This paper can provide reference for relevant researches in terms of research perspective, research ideas and research spatial scale, and provide guidance for the protection, development and planning of traditional villages

Here, we report a high-quality draft genome of a Chinese radish (Raphanus sativus) cultivar. This draft contains 387.73 Mb of assembled scaffolds, 83.93% of the scaffolds were anchored onto nine pseudochromosomes and 95.09% of 43 240 protein-coding genes were functionally annotated. 184.75 Mb (47.65%) of repeat sequences was identified in the assembled genome. By comparative analyses of the radish genome against 10 other plant genomes, 2 275 genes in 780 gene families were found unique to R. sativus. This genome is a good reference for genomic study and of great value for genetic improvement of radish.