Search

The Huolin River is located in the monsoon marginal zone in Northeast China. It is an important source of the wetland system on the Northeast Plain. Recently, a dramatic reduction in the observed river runoff has resulted in a record high level of dried-up days in the Huolin River catchment (HRC). In this study, we used the hydrological simulation approach of the Soil and Water Assessment Tool (SWAT) model to evaluate the influences of climate change and human activities on runoff in the HRC. The SWAT model effectively simulated the streamflow changes in the HRC with a high accuracy. The R2 values were 0.71 and 0.69 for the calibration and validation periods, respectively. In addition, the Nash-Sutcliffe efficiency (NSE) index reached 0.69 and 0.66 for the calibration and validation periods, respectively. The simulation results demonstrated that the variations in runoff have mostly been caused by combined influence of climate change and land use/land cover (LULC) changes, but the contributions of these factors varied in each period. The climate factors contributed 84.5% of runoff fluctuations before 2000, while the effect of LULC changes gradually grew to 63.6% after 2000. The increase in the influence of LULC changes was mainly apparent in the considerable growth of the areas of the arable land and construction land, which increased by 607 and 113 km2, respectively. This study provides an effective scientific basis for establishing long-term water management in catchment scale and regional social and economic development under the changing environment. HIGHLIGHTS The SWAT model has strong feasibility and applicability in monthly runoff simulation of the HRC.; Climate change played a dominant role in the runoff variation in the HRC before 2000.; The decrease in runoff in HRC is the result of a combination of climate change and human activities.;

Wind energy is one of the most important ways for clean energy,and has pollution-free,renewable and collection-available characteristics,which is developed rapidly in recent years.Compared with the traditional lowaltitude wind power generation,the tethered floating wind power generation has the advantages of high capacity coefficient and low power generation cost,and owns greater development value and potential,which has achieved a certain achievement carried by a number of countries.The research on the present tethered floating wind power generation technology is reported in this paper,which contains a conclusion of four kinds of tethered floating wind power generation technologies.The operating conception and feature of each technique type are analyzed.The critical points including design and manufacture of light and high strength tether,advanced envelope composite material,stable and intelligent control,aircraft overall design of efficient wind power generation and convenient deployment are summarized,which provide a foundation for future development and further research on this direction.

This study introduces a novel satellite image digital surface model (DSM) reconstruction framework grounded in deep learning methodology. The proposed framework effectively utilizes a rational polynomial camera (RPC) model to establish the mapping relationship between image coordinates and geographic coordinates. Given the expansive coverage and abundant ground object data inherent in satellite images, we designed a lightweight deep network model. This model facilitates both coarse and fine estimation of a height map through two distinct stages. Our approach harnesses shallow and deep image information via a feature extraction module, subsequently employing RPC Warping to construct feature volumes for various angles. We employ variance as a similarity metric to achieve image matching and derive the fused cost volume. Following this, we aggregate cost information across different scales and height directions using a regularization module. This process yields the confidence level of the current height plane, which is then regressed to predict the height map. Once the height map from stage 1 is obtained, we gauge the prediction's uncertainty based on the variance in the probability distribution in the height direction. This allows us to adjust the height estimation range according to this uncertainty, thereby enabling precise height value prediction in stage 2. After conducting geometric consistency detection filtering of fine height maps from diverse viewpoints, we generate 3D point clouds through the inverse projection of RPC models. Finally, we resample these 3D point clouds to produce high-precision DSM products. By analyzing the results of our method's height map predictions and comparing them with existing deep learning-based reconstruction methods, we assess the DSM reconstruction performance of our proposed framework. The experimental findings underscore the robustness of our method against discontinuous regions, occlusions, uneven illumination areas in satellite imagery, and weak texture regions during height map generation. Furthermore, the reconstructed digital surface model (DSM) surpasses existing solutions in terms of completeness and root mean square error metrics while concurrently reducing the model parameters by 42.93%. This optimization markedly diminishes memory usage, thereby conserving both software and hardware resources as well as system overhead. Such savings pave the way for a more efficient system design and development process. [ABSTRACT FROM AUTHOR]

Hypersonic vehicles are susceptible to considerable aerodynamic heating and noticeable aerothermoelastic effects during flight due to their high speeds. Functionally graded materials (FGMs), which enable continuous changes in material properties by varying the ratio of different materials, provide both thermal protection and load-bearing capabilities. Therefore, they are widely used in thermal protection structures for hypersonic vehicles. In this work, the aerothermoelastic behaviors of functionally graded (FG) plates under arbitrary temperature fields are analyzed via a semianalytical method. This research develops a method considering the influence of thermal loading, specifically the decrease in stiffness due to thermal stresses, as well as the correlation between material properties and temperatures under arbitrary temperature fields, based on Ritz's method. The classical plate theory, von–Karman's large defection plate theory and piston theory are employed to formulate the strain energy, kinetic energy and external work functions of the system. This paper presents a novel analysis of static aerothermoelasticity of FG plates, in addition to the linear/nonlinear flutter under arbitrary temperature fields, such as uniform, linear and nonlinear temperature fields. In addition, the effects of the volume fraction index, dynamic pressure, and temperature increase on the aerothermoelastic characteristics of FG plates are analyzed. [ABSTRACT FROM AUTHOR]