Due to their perfect correlation properties, complementary sequences (also called complementary codes) have been widely used in communication, radar, information security and other fields. In addition, there are deep connections between complementary sequences and mathematical structures such as Hadamard matrices, Reed-Muller codes, difference families, and generalized Boolean functions. In view of its important theoretical significance and application value, complementary sequences have been a hot research topic in the field of sequence coding, and a large number of research results have been reported. The objective of this paper is to give a well-rounded treatment of complementary sequences, focusing on the construction methods and parameters of complementary sequences, mutually orthogonal complementary sequences, and Z-complementary sequences.

Reaction-diffusion problems in several different types of domains are investigated in this paper, which describes spatial expansion of population. Compared with the classical Cauchy problem, diffusion problems are presented in fixed domains, evolving domains and free boundaries. According to the theoretical results of the corresponding problems, the differences and connections of diffusion in different domains are analyzed.

Zanthoxylum nitidum (Roxb.) DC., a kind of Zanthoxylum plant of Rutaceae family, is mainly distributed in Guangxi, Fujian, Guangdong and Yunnan provinces in China. The root, stem, leaf and peel ofZ. nitidum can be used for medicine, which has the effects of promote blood circulation to remove blood stasis, promote qi circulation to relieve pain, disperse wind to dredge collaterals and remove toxicity to achieve detumescence. It is one of the national medicines with Guangxi characteristics, and is the classic Laoban medicine of Yao people “Ru Shan Hu” and Zhuang medicine “Liang Bei Zhen”. At present, the chemical components isolated from Z. nitidum, including alkaloids, coumarins, lignans, flavonoids and other compounds, which possess anti-inflammatory, analgesic, hemostatic, antitumor, antibacterial and other pharmacological effects. The chemical constituents and pharmacological activities of Z. nitidum at home and abroad in recent five years are reviewed based on literatures search in this paper, which will provide references for further research and development of the medicinal values of this plant.

With the improvement of people’s living standards, the household power load is also gradually increasing. Aiming at reducing household power expenditure, and based on the demand responseandand the environment of time phased pricing, a two-tier optimization strategy is adopted.Firstly, the upper layer of the strategy is the classified dispatching of household electrical equipment. Through the classified adjustment of household equipment, the schedulable load can be adjusted from the time period of high electricity price to the normal and valley periods of low electricity price, so as to greatly reduce the power consumption expenditure of household users; Secondly, the lower layer adjusts the output period of photovoltaic power generation equipment and energy storage equipment, and makes rational and efficient use of photovoltaic energy through the cooperation of energy storage equipment and photovoltaic equipment. Finally, taking a typical household load configuration as an example, the improved second-order oscillatory particle swarm optimization algorithm is used to analyze different scenarios such as power consumption period optimization, power consumption period and photovoltaic optimization, and verify the effectiveness of the two-tier optimal scheduling used in this paper.

The integrated energy system combining wind power generation and electricity to gas is an effective way to realize energy efficient utilization and has great development potential. How to rationally plan and dispatch the integrated energy systemis a key problem to be solved urgently. In this paper, the operation process of electricity to gas is divided into two stages:electric hydrogen production and hydrogen methanation. Firstly, in the stage of water electrolysis hydrogen production, combining with the future development trend of hydrogen energy demand, unstable wind power is converted into hydrogen to supply hydrogen load.Secondly, with the goal of minimizing the sum of operation cost and carbon emission cost, an economic optimal dispatching model of the park comprehensive energy system including wind power-hydrogen energy-electric power to gas (P2G) is established. Simulations showthat compared with the traditional electric power to gas contained in the system, the model proposed can realize energy efficient utilization, improve the economic benefit of integrated energy system and low carbon, and the total cost is reduced by 16.61%. Finally, the weight coefficient is introduced to analyze the sensitivity of the system, and the reasonable range is obtained for reference.

The accurate estimation of battery state of charge (SOC) is very important for the management of electric vehicle power battery, and electric vehicles often encounter the mutation of SOC data in actual operation. At the same time, there are some errors in the established battery models and noise models, which lead to the poor self adaptability and robustness of the traditional extended Kalman filter algorithm in the process of SOC estimation. To solve these problems, this paper proposes to use the adaptive fading extended Kalman filter algorithm (AFEKF) to estimate the SOC of lithium-ion battery. The fading factor is introduced to adaptively iterate the system noise covariance, so as to update the optimal Kalman gain in real time and reduce the influence of factors such as data burst and battery model error.It can be seen from the experimental comparison under complex working conditions, thatcompared with the standard EKF, the SOC estimation accuracy of AFEKF can be improved by about 0.78% under NEDC condition and 0.5% under variable current condition. At the same time, it can converge to the real value faster and more smoothly when the initial value of battery SOC is inaccurate, which shows that AFEKF algorithm has higher estimation accuracy and better robustness than EKF.

The problem of unbalanced mid-point voltage of VIENNA rectifier will lead to unbalanced voltage stress on the two equalizing capacitors and the main switching device, resulting in the distortion of the input current waveform on the AC side, which greatly reduces the reliability of the system. To solve this problem, this paper studies the effect of the traditional three-level space vector modulation on the midpoint voltage of the VIENNA rectifier, so that an improved SVPWM control strategy is proposed to suppress the fluctuation of the midpoint potential. The combination of the three-phase current polarity on the input side further divides the traditional sector, and through the judgment of the new sector and the adjustment factor of the positive and negative small vectors, the effect of the middle vector is cancelled to achieve the midpoint balance. Finally, compared with the traditional SVPWM, it is verified by simulation that the midpoint potential and current fluctuations of the proposed control strategy are reduced from ±5 V and ±18 A to ±2.5 V and ±7.5 V respectively, which effectively suppresses the problem of midpoint voltage imbalance.

Aiming at the problem of low detection accuracy due to the large number of small-scale targets in the detection of masks worn by people in public places, the feature pyramid structure of YOLOv3 is improved by the method in this paper. Firstly, the rich location information of the low-level feature map is transmitted to the middle-level and high-level feature map by using the jump connection and the location feature enhancement module LFE containing channel attention, so as to strengthen the recognition of small targets. Secondly, the bounding box regression using the CIoU loss function improves the positioning accuracy of the algorithm. In addition, nonstandard wearing of masks is also detected. The experimental results show that on the self-made mask wearing dataset, the mAP of the improved YOLOv3 algorithm reaches 86.96%, which is 3.30% higher than that of the YOLOv3 algorithm. The result is also better than those of the mainstream algorithms such as Faster R-CNN, SSD300, DSSD321 and YOLOv4. The detection speed FPS of the algorithm reaches 39.2 frame/s, which is only 2.2 frame/s lower than that of YOLOv3, meeting the requirements of real-time detection.

With the development of mobile location technology, the point-of-Interest (POI) recommendation technology has become one of the research hotspots in the field of recommendation system. Limited by the check-in ability of users, there is a serious data sparsity problem in POI recommendation, what’s more, POI recommendations with combining multiple sources of data is faced with the challenges of multiple privacy. Because data from multiple sources have privacy characteristics of diversity and pluralism, the mechanism of privacy leakage is more complex and diverse, which makes the privacy problem more challenging. To solve this problem, a multi-source POI recommendation with attention mechanism and privacy protection, MultiAM&PP_POI, is proposed in this paper. In order to achieve effective data fusion, LDA topic model to extract users’ potential features in different domains is used in this paper, and an attention mechanism is used to adaptively train the influence of potential features in different domains on POI recommendation results. Meanwhile, multi-layer perceptron method is used to realize the transfer of potential features in different domains. As for the privacy problem in the recommendation of multi-source POI, the federated learning framework is used to save the original data locally without uploading, so each participant only needs to interact with the potential features after encryption. The attention mechanism is improved so multi-layer perceptron can finish training in ciphertext state to protect the security of user privacy. Finally, through experimental verification, the proposed model can effectively improve the recommendation accuracy by 3.05% and 4.42% compared with the single-source federated model and other cross-domain models on the premise of protecting users’ privacy.

Compared with simple questions, multi-hop questions are more in line with people's daily questioning methods. At the same time, the research on the multi-hop knowledge graph question-answering (KGQA) algorithm is useful to enhance the intelligent question answering system. However, the existing multi-hop KGQA methods show weak answer reasoning ability in 2 and 3-hop questions and incomplete knowledge graph. To solve this problem, a multi-hop KGQA based on convolution reasoning is proposed in this paper. A question embedding model combining character features and semantic features is developed according to the semantic similarity between questions and relationships to obtain more expressive question embedding. Furthermore, to enhance the long link reasoning ability of the algorithm, an answer reasoning model based on convolutional neural network (CNN) is proposed to extract the high-order information of the embedding. The experimental results on MetaQA dataset demonstrate that compared with the five existing methods, the new algorithm improves the prediction accuracy of the 2-hop and 3-hop questions in the complete knowledge graph and incomplete knowledge graph by 1.7%, 1.3%, 9.4%, and 9.3%, respectively.

The Mittag-Leffler projective synchronization of the fractional order Newton-Leipnik chaotic system is investigated in this paper. By utilizing input control, and based on proper Lyapunov function, the Mittag-Leffler projective synchronization of fractional order Newton-Leipnik systems for system parameters known or unknown is realized in 6 s under nonlinear feedback and self-adaptive schemes. Suitable numerical examples are presented to demonstrate the effectiveness of the proposed control method.

Based on the Rubin causal model, the interaction effects between the treatment and the covariates in the compliance sub-population are obtained, by estimating the complier average causal effect parameter with likelihood function. Simulation studies demonstrate that the proposed inference procedure performs well. The proposed method is applied to the data of the rural residents and the migrant residents in China in 2013, using Mincer earnings function to evaluate the impact of migrant work on the rate of return to education. The empirical results show thatthe rate of return education of dependent subgroups of migrant workers increases by 3.22%.

Zn-modified biochar (ZnBC) was prepared from bamboo biochar by co-precipitation loading ZnO. The adsorption performance of ZnBC for Cr(Ⅵ) in wastewater was investigated by batch experiments. The ZnBC before and after adsorption was characterized by SEM, XRD, FTIR and XPS. The experimental results show that the adsorption of Cr(Ⅵ) by ZnBC is the best at pH=7, reaction time 720 min and reaction temperature 298 K. The adsorption results of Cr(Ⅵ) conform to the pseudo-second-order (PSO) and Langmuir model theory, indicating that the adsorption types are chemical adsorption and monolayer adsorption. The saturated adsorption capacity fitted by Langmuir model is 106.383 mg/g. The coexisting ion experiments show that ZnBC has good selective adsorption for Cr(Ⅵ). The adsorption mechanism of Cr(Ⅵ) by ZnBC mainly includes photocatalytic reduction, functional group complexation, cation-π and precipitation. The results show that ZnBC has great application potential as adsorbent for removing Cr(Ⅵ) from aqueous solution.

To explore the mechanism of Rubus suavissmus S. Lee in the intervention of type 2 diabetes mellitus, type 2 diabetic rats were fed with high-fat and high-sugar diet combined with streptozotocin (STZ) to observe the changes of blood glucose and pancreatic tissue. The active ingredient targets and type 2 diabetes mellitus related genes of Rubus suavissmus S. Lee were searched and screened by systematic pharmacology method, and enrichment analysis was conducted to predict their possible signaling pathways. Molecular docking verification was conducted between the screened core ingredients and the core target, and the molecular mechanism was explored. The results showed that Rubus suavissmus S. Lee significantly reduced blood sugar in diabetic model rats (P<0.05), and at the same time improved its islet cell damage. KEGG pathway enrichment analysis showed that cancer signaling pathway, FOXO signaling pathway and HIF-1 signaling pathway were closely related to type 2 diabetes mellitus. The molecular docking results showed that baicalin, quercetin and caffeic acid may be the material basis for the anti-glycemic treatment of type 2 diabetes by Rubus suavissmus S. Lee, which was related to the regulation of MAPK1, EGFR, SRC, AKT1, PIK3R1 and PTPN11 signaling pathways.

Based on previous studies, citrus endophytic fungus Nemania sp. LJZ-Y-11 was selected for fermentation, extract preparation and evaluation of its antimicrobial activity, aiming to lay a foundation for the development and utilization of its metabolites. The antifungal and antibacterial activities of the ethyl acetate extract were determined by using a mycelium growth rate method and toxic medium coating method, respectively. The results showed that the ethyl acetate extract of LJZ-Y-11 exhibited an excellent antifungal activity against most of tested plant pathogenic fungi, and had an antibacterial activity against 10 animal pathogens to some extent. The inhibitory rate against 9 plant pathogenic fungi were all more than 50% at 2.5 g/L of the extract. Moreover, except that the inhibitory rate against Alternaria citri was 56.52%, the others were 100%. The toxicity of extract against 8 plant pathogenic fungi was determined furtherly, with EC₅₀ values ranging from 0.004 8 g/L to 0.154 4 g/L. There was the highest inhibitory activity against Exserohilum turcicum, Diaporthe citri and Phytophthora parasitica var. nicotianae with EC₅₀ values of 0.004 8, 0.005 3 and 0.006 7 g/L, respectively, less than 0.01 g/L, following by Colletotrichum capsici, Pestalotiopsis theae and Ceratocystis paradoxa with EC₅₀ values of 0.022 7, 0.035 6 and 0.067 9 g/L, respectively, less than 0.1 g/L; and also had a significant inhibitory activity against Alternaria oleracea and Cochliobolus miyabeanus with EC₅₀ values of 0.101 3 g/L and 0.154 4 g/L, respectively. In addition, the extract also showed significant antibacterial activities against 10 animal pathogens with MIC values of 0.078 1-2.5 g/L. There were high inhibitory activities against Bacillus subtilis, Escherichia coli, Staphylococcus aureus, Bacillus cereus, Bacillus anthraci and Monilia albican with MIC values of less than 0.2 g/L, and had the highest inhibitory activity against Bacillus subtilis with a MIC value 0.078 1 g/L. There were also strong inhibitory effects against Bacillus megaterium and Micrococcus lysodeikticus, with a MIC value of 0.625 g/L. The inhibition activity against Enterobacter aerogenes and Salmonella typhi was relatively weaker, with MIC values of 2.5 g/L. The results in this study reveal that the secondary metabolites of LJZ-Y-11 has broad-spectrum and significant antimicrobial activity against the common pathogens, providing a useful experiment basis for the development and utilization of the secondary metabolites as biological antimicrobial agents.

The physical and chemical properties, signal peptides, transmembrane structure, secretory protein types, subcellular localization, phosphorylation site modification, secondary structure and protein interaction of the human somatostatin type Ⅱ receptor (SSTR2) were analyzed by online bioinformatics software such as NCBI, ExPASy, SignalP, PSORTII, SOPMA, STRING, SWISS-MODEL, and the phylogenetic tree of SSTR2 protein was established by MegAlign software. The results showed that, the protein encoded by the gene contains 369 amino acids, the molecular formula was C₁₈₉₈H₂₉₈₄N₄₇₀O₅₁₃S₂₃, the relative molecular weight was 41 332.79, the theoretical value of isoelectric point was 9.15 and the instability coefficient was 37.16. SSTR2 was a stable alkaline hydrophilic protein with no signal peptide and 7 transmembrane regions, which acts on the plasma membrane structure. The secondary structure was mainly α-Helix belonging to 7tmGPCRs superfamily and containing one 7tmA_SSTR2 domain; proteins interacting with SSTR2 include CORT, SST, NPY, GHRL, GNAI1, GNAI2, GNAI3, SHANK1, HIVEP2. SSTR2 gene and its encoding protein were highly conserved in evolution, and may be involved in the G protein coupled receptor signal pathway and play its role. In this study, the physical and chemical properties and biological functions of SSTR2 gene were analyzed to provide theoretical basis for the in-depth study of the mechanism of SSTR2 protein in the occurrence of diseases and the research and development of targets therapies for neuroendocrine tumors and other cancer drugs.

To reveal the distribution regularity of ant species in eastern Daliangshan, Sichuan, China, distribution patterns of ant species were investigated by plot-sampling method. The vertical distribution, habitat, nesting and foraging sites of ant species were analyzed by means of collection frequency statistics. The results showed that a total of 35 630 ant individuals were collected in the survey, belonging to 135 species, 43 genera and 6 subfamilies (including 15 undetermined species). There were more ant species in coniferous forest and conifer-broadleaf mixed forest in low altitude area, but fewer ant species distribute in other vegetation, showing a narrower ecological adaptation range. There were more ant species foraging on the ground with wide vision and rich food resources. Majority of ant species built their nests in soil or under rocks with stable structure. In conclusion, the distribution pattern of ant species was affected by altitude, vegetation types, food resources richness, the stability of nesting sites, as well as the self-adaptability of ant species.

Taking shrubs in different slope positions in Jiangjiaba hills of Guilin as the research subjects, and based on the species diversity index and random forest statistical model, this paper made an in-depth analysis of the shrub species diversity of soil factors change with slope position, and clarified the influence mechanism of environmental factors on shrub species diversity. The results showed that: (1)Soil factors such as water content, available nitrogen, organic matter, available potassium, and total phosphorus were significantly different in different slope positions, and their changing laws were: water content appeared in the Foot>Middle>Upper, and available nitrogen appeared in the Middle>Foot>Upper, organic matter and available potassium appeared in the Middle> Upper>Foot, and the total phosphorus appeared in the Foot>Upper>Middle. (2)Species richness, Shannon-Wiener index and Simpson index were significantly different in different slope positions. The former two results showed the Foot>Middle>Upper, and the latter showed the Foot>Upper>Middle. (3)Organic matter, total phosphorus, available nitrogen and water content were the main soil factors that affected shrub species diversity. These results can provide references for species selection and vegetation layout for the ecological restoration and reconstruction of degraded vegetation in subtropical hilly areas.

The assessment and monitoring of ecological environment quality is an important part of SDG15, and also an important indicator for the construction and performance evaluation of innovation demonstration zone of national sustainable development agenda. Based on the Landsat TM/OLI remote sensing image data of Guilin in 2001, 2006, 2015 and 2019, the improved remote sensing ecological index (RSEI) constructed by NDVI, WET, NDBSI and LST was calculated by principal component analysis. The ecological environment quality of Guilin from 2001 to 2019 was evaluated and monitored. The results showed that: RSEI could indicate the eco-environmental quality of Guilin city better. Among the single index factors, NDBSI has the greatest influence on eco-environmental quality, and LST was the least. From 2001 to 2019, the mean value of RSEI in Guilin increased from 0.51 to 0.65, with an increase of 27.45%. The regional ecological environment quality of 60.10% was getting better, and the improvement was mainly in one grade. The ecological environment of all districts and counties was improved, and the improvement was most prominent in Quanzhou County and Guanyang County. The mean value of RSEI of Quanzhou and Guanyang Counties increased by 0.184 and 0.182, respectively, and the proportion of the area with excellent and good ecological environment quality of the two counties increased by 38.42% and 35.27%, respectively. The spatial distribution pattern of eco-environmental quality in Guilin had an important relationship with the land use types and the regulation of spatial function zoning. The distribution of the worst and poor eco-environmental quality occupies the eco-spatial function area of Yangshuo County, and the eco-environmental monitoring and protection efforts need to be strengthened.

Resources and the environment are the basic material conditions for human survival, and the evaluation of resource and environmental carrying capacity can provide a data basis for regional land and space planning. Firstly, construct an evaluation index system of resources and environment carrying capacity in Gansu Province from the three subsystems of resources (environment, economy and society). Secondly, use the entropy method to comprehensively evaluate the comprehensive carrying capacity of Gansu Province from 2004 to 2019 and the carrying capacity of the three subsystems, and the coupling coordination degree model is used to measure and analyze the internal coupling coordination of the three subsystems. Finally, the obstacle degree model is introduced to obtain the obstacle factors of Gansu Province’s resource and environmental carrying capacity improvement. The results show that from 2004 to 2019, the resource and environmental carrying capacity index of Gansu Province has increased from 0.207 in 2004 to 0.876 in 2019, showing a steady upward trend, and changing from an uncarryable stage to a strong carrying stage; The carrying capacity of resources, environment, and economic and social subsystems has shown a trend of increasing year by year, however, the level of carrying capacity of resources lags behind that of the economy, society and environment; The degree of system coordination has increased from 0.355 in 2004 to 0.935 in 2019, showing a steady increase. In 2019, it is in a stage of high coupling and high-quality coordination, and the resource, environment, and economic and social subsystems are in a state of benign coupling. The resource criterion layer is the main criterion layer that restricts the carrying capacity of resources and environment in Gansu Province. The development and utilization of natural resources, the level of pollutant emission, the level of farmland infrastructure construction, and the construction of social security systems are the main obstacles constrainting the improvement of the carrying capacity of resources and environment in Gansu Province. Research shows that the carrying capacity of resources and the environment and the internal coordination of the system in Gansu Province are currently at a relatively high level. At the same time, there is still room for improvement in the development and protection of resources and environment. Therefore, it is recommended to strengthen the unified registration of natural resources, establish long-term monitoring and early warning, improve the carrying capacity of resources and the environment in terms of mechanisms, introduce agricultural science and technology, and establish a sound ecological compensation mechanism.