Analysis of PM2.5 variation characteristics and main influencing factors in the Yangtze River Basin from 2016 to 2021

Studying the variation characteristics and main influencing factors of PM2.5 concentration in the Yangtze River Basin from 2016 to 2021 could provide references for optimizing the policy of collaborative governance of the atmospheric environment in the basin. Using the PM2.5 concentration data from 110 national stations in the Yangtze River Basin from 2016 to 2021, the temporal and spatial variation characteristics of PM2.5 were analyzed with the Theil-Sen trend analysis and Mann-Kendall statistical test methods. Combined with the Environmental Meteorological Assessment Index (EMI), the relative contributions of the two main influencing factors including the meteorological conditions and emission reduction measures, to the changes in PM2.5 concentration changes during the "13th Five-Year Plan" period (2016—2020) and the first year of the "14th Five-Year Plan" (2021) were quantitatively analyzed. The results were as follows. (1) Significant spatial variations in PM2.5 concentration distribution were found in the Yangtze River Basin was uneven in 2016-2021. The high-value areas were in the eastern part of the Hanjiang River Basin extending southward to the eastern part of the Dongting Lake Basin and the southern part of the Mintuo River, While the low-value area was in the upper and middle reaches of the Jinsha River Basin. (2) During the "13th Five-Year Plan" period, PM2.5 concentration in major cities of the Yangtze River Basin decreased year by year, with an annual variation rate of -3.62μg·m-3·a-1. However, PM2.5 concentration about 40% of the Yangtze River Basin region increased in 2021, which was mainly distributed in the upper reaches of the Yangtze River Basin and Dongting Lake Basin. (3) The PM2.5 in the western part of the basin was greatly affected by meteorological conditions, while the eastern part was greatly affected by emission sources and other factors. (4) Meteorological conditions and emission reduction measures during the "13th Five-Year Plan" period were conducive to the decrease of PM2.5 concentration.Their contribution rates to the increase of PM2.5 were -16.54% and -14.00%, respectively. Compared with the previous year, the emission reduction measures in 2021 were generally beneficial to the decrease of PM2.5 concentration (contribution rate of -5.84%), but adverse meteorological conditions (contribution rate of 4.49 %) offset part of the emission reduction effects, making a slight decrease in the PM2.5 concentration

A Block in Daqing Saltu Oilfield Study on well network reconstruction of stratigraphic system

A block in Daqing Saltu Oilfield has a large span of formation systems, large permeability grade difference, prominent inter-formation conflicts, low degree of control of multi-directional water drive, large injection and extraction well spacing in thin differential layers, and low degree of utilization, etc. In this regard, based on the existing well network, a study on the reconstruction of the formation system well network is carried out in this area. Longitudinal subdivision of the layer system, narrowing the mining span, the X, Y, Z oil layer mixed mining, adjusted to X oil layer separate mining, Y + Z oil layer mixed mining; at the same time, according to the nature of the oil layer subdivision of mining objects, X oil layer and Y + Z oil layer mining objects adjusted to medium and high permeability layer and low permeability layer. On the plane of optimizing the injection and extraction well spacing, the original 250m well spacing was adjusted to 175m area well network, which eased the development contradiction

The Effect of Ultraviolet Wavelength on Corrosion Behavior of 7075 Aluminum Alloy in the Marine Atmospheric Environment

The influence of ultraviolet rays on the corrosion behavior of 7075 aluminum alloy in the marine atmosphere was studied by salt spray corrosion test. Electrochemical methods and surface analysis techniques were used to analyze and compare the corrosion laws of 7075 aluminum alloy in the marine atmosphere under ultraviolet radiation with wavelengths of 0 nm, 185 nm, 254 nm, and 365 nm. The results showed that ultraviolet light irradiation could promote the corrosion of 7075 aluminum alloy. Oxygen was prone to chemical reactions to form oxygen atoms after being irradiated by ultraviolet rays, and oxygen atoms recombined with oxygen to form ozone in the marine atmosphere. The 7075 aluminum alloy in the marine atmosphere accelerated corrosion due to the increasing ozone content. Although there were passivation films with different degrees of protection on the surface of aluminum alloy under ultraviolet irradiation, the surface of 7075 aluminum alloy in the marine atmosphere failed to form a stable passivation film after pitting, and the corrosion rate was the fastest when the ultraviolet wavelength was 185 nm

Improved JPS Path Optimization for Mobile Robots Based on Angle-Propagation Theta* Algorithm

The Jump Point Search (JPS) algorithm ignores the possibility of any-angle walking, so the paths found by the JPS algorithm under the discrete grid map still have a gap with the real paths. To address the above problems, this paper improves the path optimization strategy of the JPS algorithm by combining the viewable angle of the Angle-Propagation Theta* (AP Theta*) algorithm, and it proposes the AP-JPS algorithm based on an any-angle pathfinding strategy. First, based on the JPS algorithm, this paper proposes a vision triangle judgment method to optimize the generated path by selecting the successor search point. Secondly, the idea of the node viewable angle in the AP Theta* algorithm is introduced to modify the line of sight (LOS) reachability detection between two nodes. Finally, the paths are optimized using a seventh-order polynomial based on minimum snap, so that the AP-JPS algorithm generates paths that better match the actual robot motion. The feasibility and effectiveness of this method are proved by simulation experiments and comparison with other algorithms. The results show that the path planning algorithm in this paper obtains paths with good smoothness in environments with different obstacle densities and different map sizes. In the algorithm comparison experiments, it can be seen that the AP-JPS algorithm reduces the path by 1.61–4.68% and the total turning angle of the path by 58.71–84.67% compared with the JPS algorithm. The AP-JPS algorithm reduces the computing time by 98.59–99.22% compared with the AP-Theta* algorithm

The Effect of Chlorine Ion on Metal Corrosion Behavior under the Scratch Defect of Coating

The influence of chloride ion on the corrosion of metal under coating with scratch defects was researched by wire beam electrode (WBE) technology and electrochemical impedance spectroscopy (EIS) technology. The results showed that the current of metal surface could be characterized by the WBE technology. In the case of scratches on the coating, the location of the damage always showed an anodic current, and the cathodic reaction took place adjacent to the damaged location. The cathode area surrounded the defect and migrated to the far end over time. With the increase of Cl- concentration, the corrosion reaction speeded up, the rate of cathode migration also increased, and the speed of coating stripping did as well. Combined with electrochemical impedance spectroscopy, uniform laws were obtained

Neddylation: a novel modulator of the tumor microenvironment

Abstract Neddylation, a post-translational modification that adds an ubiquitin-like protein NEDD8 to substrate proteins, modulates many important biological processes, including tumorigenesis. The process of protein neddylation is overactivated in multiple human cancers, providing a sound rationale for its targeting as an attractive anticancer therapeutic strategy, as evidence by the development of NEDD8-activating enzyme (NAE) inhibitor MLN4924 (also known as pevonedistat). Neddylation inhibition by MLN4924 exerts significantly anticancer effects mainly by triggering cell apoptosis, senescence and autophagy. Recently, intensive evidences reveal that inhibition of neddylation pathway, in addition to acting on tumor cells, also influences the functions of multiple important components of the tumor microenvironment (TME), including immune cells, cancer-associated fibroblasts (CAFs), cancer-associated endothelial cells (CAEs) and some factors, all of which are crucial for tumorigenesis. Here, we briefly summarize the latest progresses in this field to clarify the roles of neddylation in the TME, thus highlighting the overall anticancer efficacy of neddylaton inhibition

3D JPS Path Optimization Algorithm and Dynamic-Obstacle Avoidance Design Based on Near-Ground Search Drone

As various fields and industries have progressed, the use of drones has grown tremendously. The problem of path planning for drones flying at low altitude in urban as well as mountainous areas will be crucial for drones performing search-and-rescue missions. In this paper, we propose a convergent approach to ensure autonomous collision-free path planning for drones in the presence of both static obstacles and dynamic threats. Firstly, this paper extends the jump point search algorithm (JPS) in three dimensions for the drone to generate collision-free paths based on static environments. Next, a parent node transfer law is proposed and used to implement the JPS algorithm for any-angle path planning, which further shortens the planning path of the drones. Furthermore, the optimized paths are smoothed by seventh-order polynomial interpolation based on minimum snap to ensure the continuity at the path nodes. Finally, this paper improves the artificial potential field (APF) method by a virtual gravitational field and 3D Bresenham’s line algorithm to achieve the autonomous obstacle avoidance of drones in a dynamic-threat conflict environment. In this paper, the performance of this convergent approach is verified by simulation experiments. The simulation results show that the proposed approach can effectively solve the path planning and autonomous-obstacle-avoidance problems of drones in low-altitude flight missions

Negative Parenting Affects Adolescent Internalizing Symptoms Through Alterations in Amygdala-Prefrontal Circuitry: A Longitudinal Twin Study

BACKGROUND: The synergic interaction of risk genes and environmental factors has been thought to play a critical role in mediating emotion-related brain circuitry function and dysfunction in depression and anxiety disorders. Little, however, is known regarding neurodevelopmental bases underlying how maternal negative parenting affects emotion-related brain circuitry linking to adolescent internalizing symptoms and whether this neurobehavioral association is heritable during adolescence. METHODS: The effects of maternal parenting on amygdala-based emotional circuitry and internalizing symptoms were examined by using longitudinal functional magnetic resonance imaging among 100 monozygotic twins and 78 dizygotic twins from early adolescence (age 13 years) to mid-adolescence (age 16 years). The mediation effects among variables of interest and their heritability were assessed by structural equation modeling and quantitative genetic analysis, respectively. RESULTS: Exposure to maternal negative parenting was positively predictive of stronger functional connectivity of the amygdala with the ventrolateral prefrontal cortex. This neural pathway mediated the association between negative parenting and adolescent depressive symptoms and exhibited moderate heritability (21%). CONCLUSIONS: These findings highlight that maternal negative parenting in early adolescence is associated with the development of atypical amygdala-prefrontal connectivity in relation to internalizing depressive symptoms in midadolescence. Such abnormality of emotion-related brain circuitry is heritable to a moderate degree.</p

Near-Ground Delivery Drones Path Planning Design Based on BOA-TSAR Algorithm

With the advancement of technology and the rise of the unmanned aerial vehicle industry, the use of drones has grown tremendously. For drones performing near-ground delivery missions, the problem of 3D space-based path planning is particularly important in the autonomous navigation of drones in complex spaces. Therefore, an improved butterfly optimization (BOA-TSAR) algorithm is proposed in this paper to achieve the autonomous pathfinding of drones in 3D space. First, this paper improves the randomness strategy of the initial population generation in the butterfly optimization algorithm (BOA) via the Tent chaotic mapping method, by means of the removal of the short-period property, which balances the equilibrium of the initial solutions generated by the BOA algorithm in the solution space. Secondly, this paper improves the shortcomings of the BOA algorithm in terms of slower convergence, lower accuracy, and the existence of local optimal stagnation when dealing with high-dimensional complex functions via adaptive nonlinear inertia weights, a simulated annealing strategy, and stochasticity mutation with global adaptive features. Finally, this paper proposes an initial population generation strategy, based on the 3D line of sight (LOS) detection method, to further reduce the generation of path interruption points while ensuring the diversity of feasible solutions generated by the BOA algorithm for paths. In this paper, we verify the superior performance of BOA-TSAR by means of simulation experiments. The simulation results show that BOA-TSAR is very competitive among swarm intelligence (SI) algorithms of the same type. At the same time, the BOA-TSAR algorithm achieves the optimal path length measure and smoothness measure in the path-planning experiment