Design of Photovoltaic Tracking System Based on Fourier Fitting

[Introduction] In order to improve the power generation efficiency of photovoltaic brackets, the research and design focus is on a photovoltaic tracker based on Fourier fitting algorithm for apparent solar motion trajectory. [Method] The tracking accuracy of traditional solar motion trajectory algorithms was analyzed using MATLAB. Furthermore and an 8-order Fourier fitting solar motion trajectory tracking algorithm with better accuracy was proposed. The real-time solar motion trajectory was obtained combined with GNSS positioning technology. The system design employed the STM32 microcontroller as the microprocessor and adopted 6-axis acceleration sensor. The real-time tilt of the photovoltaic tracking bracket was determined by the projection of the gravity vector on its axis. Based on this, a three-dimensional operation model of the tracking bracket was established. By analyzing the cosine effect of sunlight on the bracket, the action angle required for the motor to operate can be obtained. At the same time, to solve the problem of shadow shielding between photovoltaic modules at dawn and dusk, the system added an inverse tracking algorithm. Considering the application of large-scale units, a master-slave motor synchronous control strategy was proposed. [Result] The Fourier fitting algorithm has higher tracking accuracy, reaching an accuracy of 10-2 orders of magnitude, one order of magnitude higher than traditional algorithms. At the same time, reverse tracking technology can save 24.3% of the photovoltaic array land area, significantly improving land use efficiency. [Conclusion] This study adopts a more accurate apparent solar motion trajectory tracking model, which effectively solves the cosine effect of solar radiation utilization, improves the power generation efficiency of power stations, realizes the construction of a safe and efficient green energy system, and promotes the promotion and achievement of China's goals of carbon peak and carbon neutrality

Retraction Note: Research on Key Technologies and Scenario Application of Emerging Business under the Energy Internet

This paper has been formally retracted at the author’s request. Requestapproved by the proceedings Editor and the Publisher on September 13, 2022

Hydrocarbon Resources within the U-shaped Line in the Southern South China Sea:Distribution Characteristics and Development Status

*李金蓉,国家海洋信息中心助理研究员。电子邮箱:[email protected]。 **方银霞,国家海洋局第二海洋研究所专属经济区与大陆架研究中心研究员。 ***朱瑛,中国海洋大学。［文摘］南海南部油气资源丰富,多年来越南、菲律宾、马来西亚、文莱无视我国海洋主权和权益,在我国U形线附近和U形线内大肆开展油气资源勘探开发活动,使得南海南部成为全球关注的焦点和热点。本文在分析研究南海中、南部主要沉积盆地构造特征的基础上,讨论了南海南部油气资源分布和开发现状,以及我国在复杂政治地理环境下的应对策略。［Abstract］The southern South China Sea contains rich hydrocarbon resources.Over many years,Vietnam,the Philippines,Malaysia and Brunei have wantonly carried out exploration and development activities of oil and gas resources near and even within China’s U-shaped boundary line,defying the maritime sovereign rights and interests of China.Consequently,the southern South China Sea has become a focus of global attention.In this article,by analyzing and studying the tectonic features of the major basins in the central and southern South China Sea,the authors discuss the distribution characteristics and development status of the oil and gas resources in the southern South China Sea,as well as China’s strategies to cope against the complex geopolitical backdrops.本文为2010年国家社科基金重大课题《南海地区国家核心利益的维护策略研究》(项目编号: 10zd&013)之子课题二《南海非生物资源权益维护》的阶段性成果

Methylation-state-specific recognition of histones by the MBT repeat protein L3MBTL2.

The MBT repeat has been recently identified as a key domain capable of methyl-lysine histone recognition. Functional work has pointed to a role for MBT domain-containing proteins in transcriptional repression of developmental control genes such as Hox genes. In this study, L3MBTL2, a human homolog of Drosophila Sfmbt critical for Hox gene silencing, is demonstrated to preferentially recognize lower methylation states of several histone-derived peptides through its fourth MBT repeat. High-resolution crystallographic analysis of the four MBT repeats of this protein reveals its unique asymmetric rhomboid architecture, as well as binding mechanism, which preclude the interaction of the first three MBT repeats with methylated peptides. Structural elucidation of an L3MBTL2-H4K20me1 complex and comparison with other MBT-histone peptide complexes also suggests that an absence of distinct surface contours surrounding the methyl-lysine-binding pocket may underlie the lack of sequence specificity observed for members of this protein family

Community Detection Based on Modularity and k-Plexes

Abstract(#br)Community identification is of great worth for analyzing the structure or characteristics of a complex network. Many community detection methods have been developed, such as modularity-based optimization models, which are widely used but significantly restricted in “resolution limit”. In this paper, we propose a novel algorithm, called modularity optimization with k -plexes (MOKP), to solve this problem, and this algorithm can identify communities smaller than a scale. The proposed algorithm uses k -plexes to generate community seeds from the whole network and assigns the remaining nodes by modularity optimization. To save computational time, we further propose the improved MOKP algorithm (IMOKP) by reducing the scale of the network before community seeds generation and adjusting rules of nodes assignment. Extensive experimental results demonstrate our proposed algorithms perform better than several state-of-the-art algorithms in terms of accuracy of detected communities on various networks, and can effectively detect small communities in terms of a newly defined index, namely small community level, on multiple networks as well

The mechanisms underlying the actions of Xuefu Zhuyu decoction pretreatment against neurological deficits after ischemic stroke in mice: The mediation of glymphatic function by aquaporin-4 and its anchoring proteins

Ischemic stroke (IS) has been associated with an impairment in glymphatic function. Xuefu Zhuyu Decoction (XFZYD) is widely used in the prevention and treatment of ischemic stroke. We hypothesized that Xuefu Zhuyu decoction pretreatment could attenuate early neurological deficits after ischemic stroke by enhancing the function of the glymphatic system. To prove our hypothesis, we carried out temporary middle cerebral artery occlusion and reperfusion surgery on C57BL/6 mice and then measured neurological score, infarct size and performed hematoxylin-eosin staining to assess stroke outcomes after 24 h of reperfusion. Subsequently, we injected fluorescent tracers in to the cisterna magna and evaluated tracer distribution in coronal brain sections. The polarization of aquaporin-4 (AQP4), colocalization of aquaporin-4, α-dystroglycan, β-dystroglycan and agrin were determined by immunofluorescence. Our research showed that pretreatment with Xuefu Zhuyu decoction significantly alleviated neurological scores, neurological deficits and pathological abnormalities in a mouse model of ischemic stroke. Importantly, Xuefu Zhuyu decoction pretreatment enhanced cerebrospinal fluid influx, protected aquaporin-4 depolarization and promoted the colocalization of aquaporin-4 with its anchoring proteins in the brain. Our findings highlight novel mechanisms underlying the neuroprotective effect of Xuefu Zhuyu decoction pretreatment on ischemic stroke-induced brain damage through the glymphatic system. Xuefu Zhuyu decoction pretreatment may offer a promising approach to slow the onset and progression of ischemic stroke

Probing NaCl hydrate formation from aqueous solutions by Terahertz Time-Domain Spectroscopy

The cooling-induced formation of hydrate in aqueous NaCl solutions was probed using terahertz time-domain spectroscopy (THz-TDS). It was found that the NaCl hydrate formation is accompanied with emergence of four new absorption peaks at 1.60, 2.43, 3.34 and 3.78 THz. Combining the X-ray diffraction measurement with the solid-state based density functional theory (DFT) calculations, we assign the observed terahertz absorption peaks to the vibrational modes of the formed NaCl⋅2H2O hydrate during cooling. This work dedicates THz-TDS based analysis great potential in studying ionic hydrate and the newly revealed collective vibrational modes could be the sensitive indicators to achieve quantitative analysis in phase transitions and lattice dynamics

liver-enriched gene 1a and 1b Encode Novel Secretory Proteins Essential for Normal Liver Development in Zebrafish

liver-enriched gene 1 (leg1) is a liver-enriched gene in zebrafish and encodes a novel protein. Our preliminary data suggested that Leg1 is probably involved in early liver development. However, no detailed characterization of Leg1 has been reported thus far. We undertook both bioinformatic and experimental approaches to study leg1 gene structure and its role in early liver development. We found that Leg1 identifies a new conserved protein superfamily featured by the presence of domain of unknown function 781 (DUF781). There are two copies of leg1 in zebrafish, namely leg1a and leg1b. Both leg1a and leg1b are expressed in the larvae and adult liver with leg1a being the predominant form. Knockdown of Leg1a or Leg1b by their respective morpholinos specifically targeting their 5′-UTR each resulted in a small liver phenotype, demonstrating that both Leg1a and Leg1b are important for early liver development. Meanwhile, we found that injection of leg1-ATGMO, a morpholino which can simultaneously block the translation of Leg1a and Leg1b, caused not only a small liver phenotype but hypoplastic exocrine pancreas and intestinal tube as well. Further examination of leg1-ATGMO morphants with early endoderm markers and early hepatic markers revealed that although depletion of total Leg1 does not alter the hepatic and pancreatic fate of the endoderm cells, it leads to cell cycle arrest that results in growth retardation of liver, exocrine pancreas and intestine. Finally, we proved that Leg1 is a secretory protein. This intrigued us to propose that Leg1 might act as a novel secreted regulator that is essential for liver and other digestive organ development in zebrafish