Fractional Calculus Guidance Algorithm in a Hypersonic Pursuit-Evasion Game

Aiming at intercepting a hypersonic weapon in a hypersonic pursuit-evasion game, this paper presents a fractional calculus guidance algorithm based on a nonlinear proportional and differential guidance law. First, under the premise of without increasing the complexity degree of the guidance system against a hypersonic manoeuvering target, the principle that the differential signal of the line-of-sight rate is more sensitive to the target manoeuver than the line-of-sight rate is employed as the guidelines to design the guidance law. A nonlinear proportional and differential guidance law (NPDG) is designed by using the differential derivative of the line-of-sight rate from a nonlinear tracking differentiator. By using the differential definition of fractional calculus, on the basis of the NPDG, a fractional calculus guidance law (FCG) is proposed. According to relative motions between the interceptor and target, the guidance system stability condition with the FCG is given and quantitative values are also proposed for the parameters of the FCG. Under different target manoeuver conditions and noisy conditions, the interception accuracy and robustness of these two guidance laws are analysed. Numerical experimental results demonstrate that the proposed guidance algorithms effectively reduce the miss distance against target manoeuvers. Compared with the NPDG, a stronger robustness of the FCG is shown under noisy condition

Design of Punching Process and Assembly Process for Agricultural Machinery Chain Attachment

According to the study and analysis of the part structure characteristic and conventional process,the compound die processing scheme is selected. It means that the five processes of cutting,stamping,ribbing,punching and leveling can be completed on a pair of mold. Although the mold structure is relatively complex,but it is good way to save the number of mold,the processing efficiency is improved and the product quality stable is ensured. Also,the structure characteristics of the mold and the key problem the process should be paid attention are introduced

Runoff Dynamics and Associated Multi-Scale Responses to Climate Changes in the Middle Reach of the Yarlung Zangbo River Basin, China

Long-term hydro-climatic datasets and sophisticated change detection methods are essential for estimating hydro-climatic trends at regional and global scales. Here, we use the ensemble empirical mode decomposition method (EEMD) to investigate runoff oscillations at different time scales and its response to climatic fluctuations in the middle of the Yarlung Zangbo River Basin (MYZRB) over the period 1961–2009. In the study region, results revealed that the runoff presented an overall nonlinear and nonstationary decreasing-increasing alternative trend with weak quasi-three-year and unobvious quasi-five-year cycles at the inter-annual scale, while, significance was discovered with quasi-12-year and quasi-46-year cycles at the inter-decadal scale. Variance contribution rates of the hydrological components suggested that the inter-annual oscillations played an essential role in the runoff variations in the MYZRB. According to the reconstructed inter-decadal runoff series, the runoff may keep declining in future. For the response of runoff to climate change, overall, the runoff had a positive correlation with precipitation and a negative correlation with extreme temperature. But the runoff did not show obvious correlation with mean temperature. Furthermore, from a temporal scale point of view, the inter-annual runoff showed significant response to the inter-annual precipitation. The inter-decadal runoff strongly responded to the inter-annual extreme temperature. These findings will help us understand the hydro-climatic intrinsic mechanism in the MYZRB and develop better water resources management to account for climate change impact

Pinning energies of organic semiconductors in high-efficiency organic solar cells

With the emergence of new materials for high-efficiency organic solar cells (OSCs), understanding and finetuning the interface energetics become increasingly important. Precise determination of the so-called pinning energies, one of the critical characteristics of the material to predict the energy level alignment (ELA) at either electrode/organic or organic/organic interfaces, are urgently needed for the new materials. Here, pinning energies of a wide variety of newly developed donors and non-fullerene acceptors (NFAs) are measured through ultraviolet photoelectron spectroscopy. The positive pinning energies of the studied donors and the negative pinning energies of NFAs are in the same energy range of 4.3-4.6 eV, which follows the design rules developed for fullerene-based OSCs. The ELA for metal/organic and inorganic/organic interfaces follows the predicted behavior for all of the materials studied. For organic-organic heterojunctions where both the donor and the NFA feature strong intramolecular charge transfer, the pinning energies often underestimate the experimentally obtained interface vacuum level shift, which has consequences for OSC device performance.Funding Agencies|Swedish Research Council [2016-05498, 2016-05990, 2020-04538]; Swedish Energy Agency [45411-1]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoeping University [2009 00971]; Wallenberg Wood Science Center (WWSC)</p

Spatial Sifferentiation and Differentiated Development Paths of Traditional Villages in Yunnan Province

Enhancing spatial quality is an important aspect of future studies on the development of traditional villages. From the perspective of spatial vitality, the degree of revitalization and utilization of traditional villages can be visually reflected and thus, corresponding development strategies can be provided. However, existing studies on traditional villages have paid little attention to the relationship between spatial vitality and development. Therefore, this study evaluates the spatial vitality of traditional villages in Yunnan Province based on Sina Weibo sign-in data, analyzes its relationship with spatial distribution characteristics, and finally, proposes development strategies based on different types of traditional villages. The study results show that first, the Sina Weibo sign-in data can well reflect the spatial vitality of traditional villages. Second, there is a significant difference between the spatial vitality of traditional villages and the spatial distribution characteristics, and we summarize the four types of traditional villages based on this difference. Overall, from the perspective of spatial vitality of traditional villages, this study provides differentiated ideas for the protection, spatial enhancement, and development of traditional villages on the one hand, and on the other hand, it also provides feasible references for rural revitalization planning in Yunnan

The Effect of Extrusion and Heat Treatment on the Microstructure and Tensile Properties of 2024 Aluminum Alloy

Hot extrusion forming is one of the best cost-effective processing methods to obtain high-strength aluminum alloys. In order to obtain high performance 2024 aluminum alloy for the aero and automobile industries, this research comprehensively uses heat treatment and reverse isothermal extrusion technology to prepare 2024 alloy. The effects of homogenization, extrusion and post-extrusion annealing treatment on the microstructure and mechanical properties of 2024 aluminum alloy were discussed in detail. The results indicate that the grain refinement of the extruded alloy material is significant. The coarse eutectic microstructure at the grain boundaries was refined, and these grains tended to be uniformly distributed after the annealing treatment. Extruded 2024 aluminum alloy material mainly has S (Al2CuMg) and Al7Cu2Fe second phases. The appearance of a large number of S phases led to a significant improvement in the properties of the alloy with an increase in tensile strength and elongation of 176% and 547%, respectively. In addition, EBSD analysis showed a significant meritocratic growth in the extrusion direction with the appearance of Copper {112} &lt;111&gt; rolling weaving, which led to process hardening and the strength improvement of the alloy

Tensor Robust Principal Component Analysis via Non-Convex Low Rank Approximation

Tensor Robust Principal Component Analysis (TRPCA) plays a critical role in handling high multi-dimensional data sets, aiming to recover the low-rank and sparse components both accurately and efficiently. In this paper, different from current approach, we developed a new t-Gamma tensor quasi-norm as a non-convex regularization to approximate the low-rank component. Compared to various convex regularization, this new configuration not only can better capture the tensor rank but also provides a simplified approach. An optimization process is conducted via tensor singular decomposition and an efficient augmented Lagrange multiplier algorithm is established. Extensive experimental results demonstrate that our new approach outperforms current state-of-the-art algorithms in terms of accuracy and efficiency

Assessing the Spatiotemporal Development of Ecological Civilization for China&rsquo;s Sustainable Development

The ecological civilization strategy in China has accelerated its national sustainability. However, few systematic evaluations of Chinese Ecological Civilization Construction (ECC) have provided detailed and timely information regarding estimations of the sustainable development levels. Here, we combined indicators and policies of the United Nations (UN) sustainable development goals (SDGs) with Chinese ecological civilization and built an integrated assessment system with mixed indicators for evaluating the sustainable development levels in five dimensions (i.e., economy, society, ecology, culture, and institutions). Based on the acquired sustainability index from the system, we revealed the spatiotemporal transitions at the national and provincial levels from 2005 to 2019 in China. Specifically, both the national and provincial ECC temporally increased in this period, while spatially, the development performance of ECC was differentiated across provinces and regions. In particular, sustainable trajectories in east China and coastal regions presented better than the west and inland. Moreover, we identified the different dimensional contributions between the top and bottom provinces in ECC development. The results showed that the institutional, social, and cultural dimensions created more effects than the economic and ecological dimensions. By analyzing the provincial development patterns, we recommend the comprehensive development of ECC across the five dimensions and suggest that addressing weak dimensions is a priority. The proposed system will elevate the sustainable development strategies and pave the way for the broadening of the framework&rsquo;s application to other regions and countries in the future

Nanosized CoO Loaded on Copper Foam for High-Performance, Binder-Free Lithium-Ion Batteries

The synthesis of nanosized CoO anodes with unique morphologies via a hydrothermal method is investigated. By adjusting the pH values of reaction solutions, nanoflakes (CoO-NFs) and nanoflowers (CoO-FLs) are successfully located on copper foam. Compared with CoO-FLs, CoO-NFs as anodes for lithium ion batteries present ameliorated lithium storage properties, such as good rate capability, excellent cycling stability, and large CoO nanoflakes; CoO nanoflowers; anodes; binder free; lithium ion batteriesreversible capacity. The initial discharge capacity is 1470 mA h g−1, while the reversible capacity is maintained at 1776 m Ah g−1 after 80 cycles at a current density of 100 mA h g−1. The excellent electrochemical performance is ascribed to enough free space and enhanced conductivity, which play crucial roles in facilitating electron transport during repetitive Li+ intercalation and extraction reaction as well as buffering the volume expansion

Clinical and Prognostic Significance of HIF-1α, PTEN, CD44v6, and Survivin for Gastric Cancer: A Meta-Analysis

<div><p>Purpose</p><p>This study was to quantitatively summarize published data for evaluating the clinical and prognostic significance of four proteins involved in hypoxia-inducible factor-1 (HIF-1α) regulation of the metastasis cascade.</p><p>Methods</p><p>Searches were performed using the MEDLINE, EMBASE, Cochrane Library, and Chinese Biomedicine databases without any language restrictions. Studies were pooled and either the summary risk ratio (RR) or odds ratio (OR) was calculated. Potential sources of heterogeneity were sought out <i>via</i> subgroup and sensitivity analyses, and publication bias was also performed.</p><p>Results</p><p>Seventeen studies evaluated HIF-1α, 20 studies evaluated phosphatase and tensin homolog (PTEN), 20 studies evaluated Survivin, and 16 studies evaluated CD44v6. Our results showed that increased HIF-1α expression was linked to a poor 5-year overall survival (RR = 1.508; 95% confidence interval (CI) 1.318–1.725; P<0.001). Decreased survival was heavily influenced by advanced tumor invasion (OR = 3.050; 95% CI 2.067–4.501; P<0.001), lymph node metastasis (1415 patients; OR = 3.486, 95% CI 2.737–4.440; P<0.001), distant metastasis (OR = 6.635; 95% CI 1.855–23.738; P = 0.004), vascular invasion (OR = 2.368; 95% CI 1.725–3.252; P<0.001), dedifferentiation (OR = 2.112; 95% CI 1.410–3.163; P<0.001), tumor size (OR = 1.921; 95% CI 1.395–2.647; P<0.001), and a higher TNM stage (OR =  2.762; 95% CI 1.941–3.942; P<0.001). Similarly, aberrant expression of PTEN, CD44v6, and Survivin were also observed in tumors that correlated with poor OS. The higher ORs of death at 5 years were 1.637 (95% CI = 1.452–1.845; P<0.001), 1.901 (95% CI = 1.432–2.525; P<0.001), and 1.627 (95% CI = 1.384–1.913; P<0.001), respectively, with an OR>2 for the main stratified meta-analyses of clinical factors.</p><p>Conclusions</p><p>Our findings indicate that HIF-1α/PTEN/CD44v6/Survivin, as measured by immunohistochemistry, can be used to predict the prognosis and potential for invasion and metastasis in Asian patients with gastric cancer. The development of strategies against this subset of proteins could lead to new therapeutic approaches.</p></div