bluuebunny/crossref_metadata_2025 huggingface dataset:
A probabilistic method for mapping earth fissure hazards
Authors: Zang Mingdong , Peng Jianbing , Xu Nengxiong , Jia Zhijie
Published: April 2021

Earth fissures caused by tectonic forces, human activities, or both seriously threaten the safety of people’s lives and properties. The Taiyuan Basin, a Cenozoic downfaulted basin located in the centre of the Fen-Wei Basin tectonic belt, in northwestern China, presents the ideal study area for a hazard assessment of earth fissures. A total of 104 earth fissures have been observed in the Taiyuan Basin, with a total length of approximately 128 km. In this paper, we proposed a probabilistic method for mapping earth fissure hazards by integrating the analytic hierarchy process (AHP), the area under the curve (AUC), and the certainty factor model (CFM). Geomorphic units, geologic formations, active faults and land subsidence zones of the Taiyuan Basin were mapped in detail. Correlations between these factors and earth fissures were evaluated through spatial modelling in ArcGIS. The AUC was introduced into the AHP to weight each factor and thus, to derive an earth fissure susceptibility map. Finally, the modelled earth fissure susceptibility was compared with a digital inventory of earth fissures to develop a probability function and map the spatial variability in failure probability through the CFM. The study indicates that active faults have the greatest contribution to the generation of earth fissures. Earth fissures are prone to develop in the piedmont alluvial-diluvial clinoplain and the transitional zone near the geomorphic boundary. This mapping procedure can assist in making rational decisions regarding urban planning and infrastructure development in areas susceptible to earth fissures.
Picking up the hydrothermal whisper at Ischia Island in the Covid-19 lockdown quiet
Authors: Falanga Mariarosaria , Cusano Paola , De Lauro Enza , Petrosino Simona
Published: April 2021

In this paper, we analyse the seismic noise at Ischia Island (Italy) with the objective of detecting the hydrothermal source signals taking advantage of the Covid-19 quiescence due to lockdown (strong reduction of anthropogenic noise). We compare the characteristics of the background noise in pre-, during and post-lockdown in terms of spectral content, energy release (RMS) and statistical moments. The continuous noise is decomposed into two independent signals in the 1−2 Hz and 2−4 Hz frequency bands, becoming sharpened around 1 Hz and 3 Hz respectively in lockdown. We propose a conceptual model according to which a dendritic system of fluid-permeated fractures plays as neighbour closed organ pipes, for which the fundamental mode provides the persistent whisper and the first higher mode is activated in concomitance with energy increases. By assuming reasonable values for the sound speed in low vapor–liquid mass fraction for a two-phase fluid and considering temperatures and pressures of the shallow aquifer fed by sea, meteoric and deep hydrothermal fluids, we estimate pipe lengths in the range 200–300 m. In this scheme, Ischia organ-like system can play both continuous whisper and transients, depending on the energy variations sourced by pressure fluctuations in the hydrothermal fluids.
Safety of traditional Chinese medicine injection based on spontaneous reporting system from 2014 to 2019 in Hubei Province, China
Authors: Huang Rui , Cai Yuanxuan , Yang Linhui , Shangguan Xiaofang , Ghose Bishwajit , Tang Shangfeng
Published: April 2021

Traditional Chinese medicine (TCM) injection is widely used in clinical settings, but its adverse drug reactions (ADRs) can be a serious public health concern. The objective is to study the safety of TCM injection and provide suggestions for clinical use. ADR reports collected by the Hubei Adverse Drug Reaction Monitoring Center from 2014 to 2019 were analysed. The safety of TCM injections was described by descriptive analysis and three signal mining methods, including the reporting odd ratio (ROR), proportional reporting ratio (PRR) and comprehensive standard method (MHRA). The findings indicate that the age groups of 0–10 and 41–80 years had the highest rates of reporting ADRs. A total of 96.41% of the ADRs occurred within one week, mostly on the same day that the injection was administered. Among the 60 TCM injections, Shenmai, Xiangdan, Salvia, Shengmai, Astragalus and Xuebijing injection had an above average ratio of severe ADRs (12.63%). A total of 99.24% of the cases improved after treatment. There were 9 deaths whose ADRs were mainly anaphylactic shock, dyspnoea and anaphylactoid reaction. In signal mining, the three methods produced 19 signals that were the same, and 14 of them were off-label ADRs. The frequency of TCM injections in children and elderly patients should be reduced and monitored strictly. Close observation is necessary during the first seven days after receiving the injection. The clinical use of Shenmai, Xiangdan, Salvia, Shengmai, Astragalus and Xuebijing injections should be investigated. Signal mining and more research are needed on TCM injections.
Aggressive and recurrent ovarian cancers upregulate ephrinA5, a non-canonical effector of EphA2 signaling duality
Authors: Jukonen Joonas , Moyano-Galceran Lidia , Höpfner Katrin , Pietilä Elina A. , Lehtinen Laura , Huhtinen Kaisa , Gucciardo Erika , Hynninen Johanna , Hietanen Sakari , Grénman Seija , Ojala Päivi M. , Carpén Olli , Lehti Kaisa
Published: April 2021

Erythropoietin producing hepatocellular (Eph) receptors and their membrane-bound ligands ephrins are variably expressed in epithelial cancers, with context-dependent implications to both tumor-promoting and -suppressive processes in ways that remain incompletely understood. Using ovarian cancer tissue microarrays and longitudinally collected patient cells, we show here that ephrinA5/EFNA5 is specifically overexpressed in the most aggressive high-grade serous carcinoma (HGSC) subtype, and increased in the HGSC cells upon disease progression. Among all the eight ephrin genes, high EFNA5 expression was most strongly associated with poor overall survival in HGSC patients from multiple independent datasets. In contrast, high EFNA3 predicted improved overall and progression-free survival in The Cancer Genome Atlas HGSC dataset, as expected for a canonical inducer of tumor-suppressive Eph receptor tyrosine kinase signaling. While depletion of either EFNA5 or the more extensively studied, canonically acting EFNA1 in HGSC cells increased the oncogenic EphA2-S897 phosphorylation, EFNA5 depletion left unaltered, or even increased the ligand-dependent EphA2-Y588 phosphorylation. Moreover, treatment with recombinant ephrinA5 led to limited EphA2 tyrosine phosphorylation, internalization and degradation compared to ephrinA1. Altogether, our results suggest a unique function for ephrinA5 in Eph-ephrin signaling and highlight the clinical potential of ephrinA5 as a cell surface biomarker in the most aggressive HGSCs.
Promotion of hydrogen evolution catalysis by ordered hierarchically porous electrodes
Authors: Yu Yihuan , Liu Pengdong , Dou Meiling , Niu Jin , Zhang Zhengping , Wang Feng
Published: April 2021

Ru-Based ordered hierarchically porous electrodes promote fast mass transfer and diffusion for hydrogen evolution under high current densities.
Natural products inCyperus rotundusL. (Cyperaceae): an update of the chemistry and pharmacological activities
Authors: Babiaka Smith B. , Moumbock Aurélien F. A. , Günther Stefan , Ntie-Kang Fidele
Published: April 2021

Cyperus rotundusL. (Nutgrass, family Cyperaceae) is a notorious weed which is widespread in temperate tropical and subtropical regions of the world.
Iron-catalysed hydroboration of non-activated imines and nitriles: kinetic and mechanistic studies
Authors: Bazkiaei Adineh Rezaei , Wiseman Michael , Findlater Michael
Published: April 2021

Iron-catalysed hydroboration of imines and nitriles has been developed under low catalyst loading (1 mol%) in the presence of HBpin.
Chemical and electrochemical water oxidation mediated by bis(pyrazol-1-ylmethyl)pyridine-ligated Cu(i) complexes
Authors: Makhado T. , Das B. , Kriek R. J. , Vosloo H. C. M. , Swarts A. J.
Published: April 2021

The first CuI-complexes as homogeneous chemically and electrocatalytically driven WOCs operating at low and near-neutral pH.
Calculating the magnetic force of solenoid inductor wound by rectangular cross‐section wire
Authors: Hao Shuangpeng , Li Baoming
Published: April 2021

A new semi‐analytical expression is presented based on two integrations for calculating the magnetic force of a solenoid inductor wound by rectangular cross‐section wire. The authors simplified the solenoid inductor coil to a collection of circular coils, and the current density of the coils in the radial direction which was inversely proportional to its radius is considered. The obtained expressions can be implemented by adaptive Gaussian quadrature integration with MATLAB programming. In addition, they used the filament method and the finite element method to calculate the magnetic force on the solenoid inductor coil. The correctness of the semi‐analytical expressions was verified by comparing the results of the semi‐analytical numerical method with those of the filament method and the finite element method, respectively. The derived semi‐analytical expressions of magnetic force allow a low computational time compared with the filament method and the finite element method to a specific accuracy. The calculation results show that: the solenoid inductor coil tends to compress in the axial direction, and the axial magnetic force on the outermost coils is the largest; the solenoid inductor coil tends to expand outward in the radial direction, and the radial magnetic force on the intermediate coil is the largest.
High‐quality reversible data hiding scheme using sorting and enhanced pairwise PEE
Authors: Kaur Gurjinder , Singh Samayveer , Rani Rajneesh , Kumar Rajeev , Malik Aruna
Published: April 2021

This paper proposes a novel reversible data hiding (RDH) technique using sorting and pairwise prediction error expansion (PEE) to improve embedding capacity (EC) while retaining the quality of cover image. The proposed scheme traverses alternate pixels of the cover image in a zig‐zag order to construct two independent sets for sequential embedding. The pixels of each set are sorted in an increasing order of their rhombus mean followed by a two‐pass data embedding by dividing the sets into 1 × 3 size blocks based on some pre‐defined criteria. In pass 1, two prediction errors are calculated for the first and the last pixels using their rhombus means; and pairwise mapping is modified and exploited to embed the secret data in such a way that the value of the first pixel is either increased or remains unchanged, and the value of the last pixel is either decreased or remains unchanged. In pass‐2, the middle pixel is utilised to predict the first and last pixels and the values of the first pixel and the last pixel are either decreased or remains unchanged and either increased or remains unchanged, respectively. In contrast to some existing recovery‐based methods, the proposed pass‐2 guarantees to complement the changes made in pass‐1, thereby boosting the quality along with increased EC. The experimental results show that the proposed method achieves better embedding performance than the state‐of‐the‐art RDH techniques. More specifically, the proposed method gets an increment by an average of 0.46 dB and 1.01 dB for embedding 10,000 bits and 20,000 bits respectively over its closest prior art.
Study on GNSS‐R multi‐target detection and location method based on consistency checking
Authors: Liu Cheng , Xiang Hengyong , Li Fang , Shi Huli , Wang Wei , Gao Weiguang , Zhang Jie , Ning Yongke
Published: April 2021

The use of GNSS reflected signals to carry out passive detection of space targets is an emerging technical field. Unlike the traditional GNSS‐R in large‐scale environments such as oceans, vegetation, ice and snow, it is required to identify different targets within the detection range, which is one of the biggest challenges. To solve this problem, a hyperboloid observation equation based on the TDOA location model is constructed, which can eliminate the GNSS satellite orbit error, the satellite atomic clock error and the detection receiver clock error via differential technique. The consistency checking theory based on hypothesis and test is used to detect and distinguish different targets while locating. The simulation results show that the target detection and location accuracy can reach tens of metres, and when the different space targets are separated by 50 m, 100 m, 150 m, 200 m, and 250 m in sequence, the detection success rate of the method is 67.25%, 87.50%, 95.75%, 99.25%, and 99.75%, respectively, which indicates the feasibility and effectiveness of the method. The study provides a feasible technical approach for solving the multi‐target problem in GNSS‐R space target passive detection.
Visual inspection for transformer insulation defects by a patrol robot fish based on deep learning
Authors: Ji Hongxin , Cui Xiwang , Ren Weiyan , Liu Liqing , Wang Wei
Published: April 2021

In order to effectively detect the internal insulation defects of large transformers, a miniature patrol robot fish is designed and used to observe the pressboard inside the transformer, which can visually inspect the insulation condition of the pressboard. In the process of visual inspection by a patrol robot fish, insulation defects observed in the transformer (such as discharge carbon marks, pressboard cracks, etc.) are small size, indistinctive colour contrast and different shapes. The key purpose of the patrol robot fish is to identify the defect targets and defect types intelligently and quickly from the images taken by the camera on the fish. Considering that there are abundant insulation defects in transformers and a lack of samples for learning, a vision detection method based on deep learning network is proposed in this study. The proposed method integrates the variable autoencoder into the traditional Faster‐RCNN target detection network and constructs an improved Faster‐RCNN that enhances feature extraction. This method expands the small‐scale training sample set and improves the generalisation performance of the model. In order to verify the effectiveness of the proposed method, the improved network is trained and tested, and the test results show that the improved network training model can accurately identify and mark the carbon marks on the pressboard surface.
Euclid: Impact of non-linear and baryonic feedback prescriptions on cosmological parameter estimation from weak lensing cosmic shear
Authors: Martinelli M. , Tutusaus I. , Archidiacono M. , Camera S. , Cardone V. F. , Clesse S. , Casas S. , Casarini L. , Mota D. F. , Hoekstra H. , Carbone C. , Ilić S. , Kitching T. D. , Pettorino V. , Pourtsidou A. , Sakr Z. , Sapone D. , Auricchio N. , Balestra A. , Boucaud A. , Branchini E. , Brescia M. , Capobianco V. , Carretero J. , Castellano M. , Cavuoti S. , Cimatti A. , Cledassou R. , Congedo G. , Conselice C. , Conversi L. , Corcione L. , Costille A. , Douspis M. , Dubath F. , Dusini S. , Fabbian G. , Fosalba P. , Frailis M. , Franceschi E. , Gillis B. , Giocoli C. , Grupp F. , Guzzo L. , Holmes W. , Hormuth F. , Jahnke K. , Kermiche S. , Kiessling A. , Kilbinger M. , Kunz M. , Kurki-Suonio H. , Ligori S. , Lilje P. B. , Lloro I. , Maiorano E. , Marggraf O. , Markovic K. , Massey R. , Meneghetti M. , Meylan G. , Morin B. , Moscardini L. , Niemi S. , Padilla C. , Paltani S. , Pasian F. , Pedersen K. , Pires S. , Polenta G. , Poncet M. , Popa L. , Raison F. , Rhodes J. , Roncarelli M. , Rossetti E. , Saglia R. , Schneider P. , Secroun A. , Serrano S. , Sirignano C. , Sirri G. , Starck J.-L. , Sureau F. , Taylor A. N. , Tereno I. , Toledo-Moreo R. , Valentijn E. A. , Valenziano L. , Vassallo T. , Wang Y. , Welikala N. , Zacchei A. , Zoubian J.
Published: April 2021

Upcoming surveys will map the growth of large-scale structure with unprecented precision, improving our understanding of the dark sector of the Universe. Unfortunately, much of the cosmological information is encoded on small scales, where the clustering of dark matter and the effects of astrophysical feedback processes are not fully understood. This can bias the estimates of cosmological parameters, which we study here for a joint analysis of mock Euclid cosmic shear and Planck cosmic microwave background data. We use different implementations for the modelling of the signal on small scales and find that they result in significantly different predictions. Moreover, the different non-linear corrections lead to biased parameter estimates, especially when the analysis is extended into the highly non-linear regime, with the Hubble constant, H0, and the clustering amplitude, σ8, affected the most. Improvements in the modelling of non-linear scales will therefore be needed if we are to resolve the current tension with more and better data. For a given prescription for the non-linear power spectrum, using different corrections for baryon physics does not significantly impact the precision of Euclid, but neglecting these correction does lead to large biases in the cosmological parameters. In order to extract precise and unbiased constraints on cosmological parameters from Euclid cosmic shear data, it is therefore essential to improve the accuracy of the recipes that account for non-linear structure formation, as well as the modelling of the impact of astrophysical processes that redistribute the baryons.
Optical nebular emission following the most luminous outburst of Aquila X-1
Authors: Panizo-Espinar G. , Muñoz-Darias T. , Armas Padilla M. , Jiménez-Ibarra F. , Casares J. , Mata Sánchez D.
Published: April 2021

Aquila X-1 is a prototypical neutron star low mass X-ray binary and one of the most studied X-ray transients. We present optical spectroscopy obtained with the Gran Telescopio Canarias (10.4 m) during the 2016 outburst, the brightest recorded in recent times and which showed a standard evolution with hard and soft accretion states. Our dataset includes a dense coverage of the brightest phases of the event, as well as the decay towards quiescence. We searched for optical winds by studying the profiles and evolution of the main emission lines and found no indisputable wind signatures, such as P-Cyg profiles. Nonetheless, our detailed analysis of the particularly strong and broad Hαemission line, detected at the end of the outburst, is consistent with the presence of a nebular phase produced by optically thin ejecta at ∼800 km s−1or, alternatively, an extended disc atmosphere. We discuss these possibilities as well as the similarities with the phenomenology observed in other black hole and neutron star systems. Our study suggests that optical nebular phases might be a relatively common observational feature during the late stages of low mass X-ray binaries’ outbursts, enabling us to probe the presence of outflows at low-to-intermediate orbital inclinations.
Research on Power System Control Based on Emergency Response
Authors: Weihua Chen , Renzhong Shan , Cuifen Bai , Youdong Zhang
Published: April 2021

In order to prevent power system disasters and improve power system emergency response capability, the theoretical basis of integration power system disaster prevention and emergency response into social disaster prevention and emergency response was studied. Based on the statistical summary of power system disasters and emergency treatment, the necessity and feasibility of integration power disaster prevention and emergency response into social disaster prevention and emergency response was analyzed. And the mode of integration power disaster prevention and emergency response into social disaster prevention and emergency response was discussed, including weak contact mode, integration mode, unified coordination mode, etc. Then, the path map of integration power disaster prevention and emergency response into social disaster prevention and emergency response was constructed. The research shows that integration of power disaster prevention and emergency response into social disaster prevention and emergency response can realize the prevention and early control of electronic system disasters through data sharing and action coordination, so as to improve the level of power disaster prevention and emergency response.
A Secure and Fast Access Protocol for Collecting Terminal in Power Internet of Things based on Symmetric Cryptographic Algorithm
Authors: Zhai Feng , Zhao Yingjie , Kong Lingda , Zhang Xiaojuan , Jiang Lin
Published: April 2021

The development of Power Internet of Things has brought a variety of access requirements for massive collecting terminals. Based on the characteristics of security attributes of Power Internet of Things, this paper proposes a secure access protocol based on symmetric cryptographic algorithm for the large number of collecting terminals with limited manufacturing cost, computing power and storage resources. This protocol only uses the symmetric cryptographic algorithm which has the fast computing speed and low resource consumption, and the protocol can realize two-way identity authentication between the collecting terminal and master station. At the same time, combined with the historical access mechanism, it improves the access efficiency of the collecting terminals, and realizes the safe and fast access of the collecting terminal. Finally, compared with other protocols, the proposed protocol is also effective in security and performance.
Online Identification on Operational Risks of the Second and Third Defense Line of UHVDC Sending-End Power Grid
Authors: Yu Rui , Xiang Zhen , Xiong Jun , Jianhui Gu , Tang Fan , Wang Xiaoyu , Wang Xiongfei
Published: April 2021

The paper analyzed the potential safety and stability control risk of the southwest power grid, presented the general online identification framework for operational risks of the second and third defense line of UHVDC sending-end power grid, elaborated the key techniques for realizing the aforementioned functions, including security control strategy/system protection strategy modelling, high frequency cutting generator strategy modelling , conflict detection for the control measures of the second and third defense line, practicability assessment method for security control strategy/system protection strategy, practicability assessment method of high frequency cutting generator strategy and other technologies. According to the actual application conditions of the southwest power grid, the system may provide dispatching users with more comprehensive Online identification for the operational risks the second and third defense line as well as discover the potential safety hazards and risks during operation of the power grid.
Online Evaluation System of Power Grid Efficiency
Authors: Weihua Chen , Renzhong Shan , Cuifen Bai , Youdong Zhang
Published: April 2021

Transmission network is an important part of power system. The operation efficiency of transmission network is one of the important indexes of power system. At present, there is still much room to improve the efficiency of China's transmission network. There is a lack of a suitable system to evaluate the operation efficiency of transmission network. In order to effectively evaluate the efficiency of transmission network, this paper establishes the evaluation index system of transmission network operation efficiency and applies it to the actual power system. The test results verify the feasibility of the proposed index system.
A Two-Stage PV Accommodation Optimization in Jinzhai County, Anhui Province with Hydropower as Stand-By Unit
Authors: Liu Tianyi , Bao Hai
Published: April 2021

In respond to the national “Photovoltaic Poverty Alleviation” and renewable energy accommodation policy, this paper proposes a two-stage PV accommodation optimization strategy based on improved PSO, PV forecast, and hydropower dispatch to tackle with the instability caused by distributed PV, since Jinzhai County, Anhui Province has both sufficient hydropower and photovoltaic. In the first stage, the hydropower reserve capacity of each period of the next day is optimized according to the PV forecast. In the second stage, real-time online optimization is carried out using the operation data to determine the amount of power generated by each PV source during each period. Finally, the optimization strategy is verified by simulations using grid operation data in Jinzhai, and the comparison is made with the thermal power standby unit. The results show that the hydropower units which has higher climbing rate can immensely increase the photovoltaic consumption, reduce the power loss and enhance the voltage stability of the network.
Secure sharing method of network data transmission based on multi-layer encryption technology
Authors: Jing Yanrong , Zhang Wenqian , Ge Lin , Li Nanfang , Shang Xiyuan , Ye Yun
Published: April 2021

In order to ensure the effect of network data transmission in scientific research institutions and avoid network information from being attacked and damaged, a secure sharing method of network data transmission based on multi-layer encryption technology is proposed. Combined with multi-layer encryption technology, the network data transmission security protocol is constructed to ensure the security and integrity of the initial file. The network information transmission security evaluation system is further constructed. The network transmission path security of scientific research institutions is tracked, evaluated and tested in real time. The network data transmission security sharing platform is constructed to ensure the safe sharing of massive and complex data Experiments have proved that the security and sharing processing effect of the network data transmission security sharing method based on multi-layer encryption technology are significantly improved compared with the traditional methods, and fully meet the research requirements.
Assessment of the Distribution Effectiveness of Labor Protective Articles in Power Supply Enterprises based on Certain Distribution System
Authors: Liu Sen , Zhu Baoyu , Li Hongyan , Gao Yang , Xu Hualei , Su Chang , Li Zhi
Published: April 2021

To further optimize the distribution of labor protective articles in certain power supply enterprise, a distribution system is established to help their type selection and allocation, and questionnaires are utilized to assess the changes in relevant knowledge, behaviors, and satisfaction among the randomly sampled respondents, and the effectiveness of the distribution arising from the adoption of the system. It is demonstrated that a remarkable increase occurs in the accuracy of employees mastering knowledge pertaining to labor protective articles, and particularly their willingness to actively learn the correct method of using the articles stands at as high as 94.7%; their satisfaction with the replacement cycle of the protective articles decreases, satisfaction with to what extent their requirements of protection are met by the articles distributed through the system significantly rises, and the proportion of the negative options in terms of willingness to wear the articles drops from 2.7% before adopting the distribution system to 0%. It is suggested that the employees’ requirements of the effectiveness and usability of the protective articles in power supply enterprises can be met quite well through this distribution system, which is of significance in providing guidance about how to enhance the practicability of such articles.
Research on Application of ETAP in Ship electric propulsion system
Authors: Liu Kai , Chen Jing
Published: April 2021

This article takes a ship electric propulsion system as a specific example, using ETAP to establish a simulation model and short-circuit current calculation. Through the calculation results, the coordination setting of the circuit breaker and the comparison with the COMPASS calculation results are carried out, and finally the selective protection and coordination analysis of the power system are completed.
Construction and application of temperature and humidity precision control model based on differentiation theory
Authors: Ye Shengli , Xia Yunfei , Hong Zhengguo , Jin Hangping
Published: April 2021

Through the construction and application of the temperature and humidity precision control model of the differentiation theory, and on the basis of customer needs, the temperature and humidity precision control model based on the differentiation theory is proposed. The core concept is to implement differential control in time and zone, and use zone control, Card edge control, dual-mode control and other control methods to achieve stable, reliable and precise control of the temperature and humidity of the production environment, so as to reduce the energy consumption of the air conditioning system.
Research on Seismic Analysis of Converter Valve of Offshore Flexible High Voltage Direct Current Considering the Effect of Initial Displacement
Authors: Zhang Lihong , Xiao Jin , Lv Wei , Zeng Di
Published: April 2021

Due to the acceleration of global energy transformation and the reduction of the cost of new energy, offshore wind power has been attached great importance by many countries. Therefore, offshore wind power transmission based on flexible HVDC transmission technology has become a hot issue in the development and research of offshore wind power. When the offshore platform is running for a long time, there may be extreme conditions of encountering earthquake. As the core component of flexible HVDC transmission, converter valve's structural safety research under earthquake is very necessary. Different from the onshore converter station and limited by the installation environment, the bottom support insulator of offshore converter valve tower may have initial displacement after being installed on the foundation plate of offshore platform. However, there is no literature on the effect of initial displacement on the dynamic characteristics and seismic performance of valve towers. In this paper, a practical engineering valve tower is taken as an example. Firstly, the influence of different initial displacements on the dynamic characteristics of valve tower is studied. Then, the dynamic analysis of valve tower under earthquake load is carried out by using time history integration algorithm. The influence of initial displacement on the structural safety of valve tower is studied by comparison method. The results of this paper can provide reference for similar projects.
Advance Evaluation of System Protection Control Strategy Based on Multi-scheme Concurrency
Authors: Liu Lin , Guo Jian , Luo Jianyu , Xu Xiongfeng , Luo Kaiming , Wang Shengming
Published: April 2021

According to rapid assessment requirement of system protection control strategy adaptability in future operation mode, combining with application status of distributed computing for power system security and stability analysis, based on design idea of asynchronism and concurrency, this paper proposes a multi-scheme concurrent computing framework suitable for coarse-grained case parallelism. By the way of multi-data section parallel, the asynchronous and concurrent scheduling management of computing task of multiple application functions under different sections is realized, which effectively improves the utilization rate of computing resources and significantly reduces the computing period of advance evaluation of system protection control strategy adaptability. The technology has been applied in provincial power grid and its effectiveness has been verified.
Flexible Control Strategy for Intelligent Building Air Conditioning System
Authors: Xue Guiyuan , Wu Chen , Niu Wenjuan , Dou Xun , Wang Shizhen , Fu Yadie
Published: April 2021

An improved optimization adjustment strategy for building heating ventilation and air conditioning (Heating Ventilation and Air Conditioning, HVAC) is proposed. The energy consumption model of building heating/refrigeration is established by using the instantaneous energy balance of heat, and then the optimal operation strategy of building HVAC energy based on weather forecast data is constructed in the range of user temperature comfort. Finally, the MATLAB and TRNSYS simulation techniques are used to verify the example. Simulation results show that the optimal operation strategy of building HVAC energy based on weather forecast data can not only significantly reduce the cost of energy use, but also effectively improve the absorption capacity of renewable energy on the building side.
Temperature measurement and identity detection system based on multiple embedded control units and LBP detection algorithm
Authors: Zhu Zhishan , Liu Aike , Chi Haifei
Published: April 2021

This paper designs a simple non-contact temperature measurement and identity recognition device based on multiple embedded control systems and feature recognition algorithms. The device can achieve multiple functions such as non-contact temperature measurement, face recognition, mask recognition, and smart alarm. The system consists of three parts: main control, interactive system and detection system: the main control selects STM32F407VGT6 to process the data returned by multiple sensors and realize the mutual communication of each system; the interactive system uses the HMI serial touch screen to realize the visualization of data and human Machine operation function; the detection system is equipped with MLX90614 temperature detection module and OpenMV4 machine vision module to realize functions such as temperature detection, face recognition and mask recognition[1]. In addition, in order to ensure the accuracy and stability of the detection results, this article specifically designs temperature data filtering and compensation algorithms, LBP feature detection algorithms and other intelligent algorithms. Through experiments, the accuracy of this device to detect 28°C-48°C is within 0.8°C, and the accuracy of identifying faces and masks is above 98%.
Research and Application of Hydraulic Injection Precise Fracturing Technology in W27 Oilfield
Authors: Li-yong Yang , Shun-li Yin , Tian-lin Zhuang , Xiao-ting Gou , Yu-qiao Du
Published: April 2021

W27 oilfield is a multi-layer heterogeneous low permeability reservoir, which has entered the middle and late stage of development. The main reservoir is flooded seriously, and the remaining oil distribution is complex. If conventional fracturing technology is adopted, the risk of longitudinal fracture communication with water layer or water-flooded layer is high, which is easy to cause high water cut after fracturing and affect the fracturing effect. According to the characteristics of fractured well reservoir, the hydraulic injection fracturing technology is optimized to optimize the position of injection point and fracturing process parameters, avoid pressing water layer, and achieve accurate reconstruction of potential reservoir. The technology was applied to 4 Wells on site, and the average daily oil gain per well was 6 tons and the average accumulated oil gain per well was 2,500 tons. Hydraulic injection precision fracturing technology has an obvious effect on water control and oil increase in W27 oilfield, which has an important guiding significance for similar reservoirs to improve the fracturing effect.
Research on improving low frequency oscillation characteristics of wind power system with DFIG-PSS-VI
Authors: He Ping , Zheng Mingming , Li Zhao , Fang Qiyuan , Wu Xiaopeng
Published: April 2021

The new energy represented by strong random wind power connecting to the power system may make the problem of inter-area low-frequency oscillation more serious. In this paper, a DFIG-PSS controller based on virtual impedance is constructed to solve the low-frequency oscillation problem in the wind power system. The step response of PSS-VI was carried out to test the effect of the controller to verify the advantages of PSS-VI than traditional PSS. The input signal of PSS-VI which is a controller based on PSS installed virtual impedance is the active power of DFIG. The output signal of PSS-VI is added to the reactive power control loop of rotor side controller of DFIG. DFIG-PSS-VI was built in Digsilent/Powerfactory software, and the simulation was carried out on the system of 4 machines and 2 regions. It is verified that PSS-VI can improve the low-frequency oscillation of wind power system.
Aging Characteristics of Lithium Titanate Batteries under Ultrahigh Discharge Rate
Authors: Liu Zehui , Wang Chu , Miao Chen , Gao Yinghui , Sun Yaohong
Published: April 2021

The aging characteristics of lithium titanate batteries under ultra-high discharge rate were studied in this paper. The discharge characteristics is highly temperature-dependent under 55C discharge rate. The capacity retention rate is about 73% after 100 cycles of 55C discharge. The in-situ analysis incremental capacity analysis (ICA) was used to analyze the aging mechanism, and it was found that the main reason for the capacity fading was the loss of active material of the positive electrode, which leads to an increase of polarization resistance under 55C discharge rate.
Research on Safety of Mine Power Supply System
Authors: Weihua Chen , Renzhong Shan , Cuifen Bai , Youdong Zhang
Published: April 2021

Electric power is one of the main supplies of mine energy. The safety of electric power is of great significance to the safety of mines. The probability of blackout is relatively small. But once it happens, the harm is great. In order to improve the safety of mine power supply, this paper summarizes the research on the safety of mine power supply system, puts forward the research direction, and prospects the development of mine power security in the future.
Development of Degassing Device for Transformer oil Based on Headspace Degassing Method
Authors: Yin Zhibin , Huo Chao , Sun Haipeng , Chen Jing
Published: April 2021

By analyzing the type and content of gas in oil, the latent faults in equipment can be found as soon as possible, and the faults can be monitored at any time. In this paper, a degassing device based on headspace degassing method is designed. The oil circuit adopts the way of oil pump and battery valve to complete the oil inlet and oil discharge. Through stirring, the dissolved gas in the oil can reach the dynamic balance in the gas-liquid two-phase, so as to realize the rapid and effective separation of the gas in the oil. At the same time, after degassing, the oil can be sent back to the body. In addition, the degassing verification of the device is carried out, and the effect is good. In the next step, the device can be integrated with the gas detection equipment to form a sealed cabinet detection equipment, which is of great significance for the technical realization and engineering application of online monitoring and live detection of power equipment.
Analysis of Backup Protection Action of a Transformer Caused by Improper Implementation of Voltage Regulation Measures
Authors: Chen Yu , Ding Hongcheng , Zhang Junwei , Ding Ganghui , Cui Jun , Hu Shengzhi
Published: April 2021

It is an effective measure for power enterprises to improve the voltage level of the system by raising and lowering the tap position of the main transformer. For the parallel operation of the main transformer, the whole process of adjusting the tap must strictly meet the conditions of parallel operation. Aiming at a case of backup protection action of main transformer caused by improper implementation of voltage regulation measures, this paper analyzes the uneven load distribution and increase of reactive power loss caused by improper adjustment of tap, and the analysis results are verified by PSCAD.
Analysis of Special Consequences and Losses of Equipment Accident in Thermal Power Plant
Authors: Kong Shuai , Yu Xuefen , Ling Zhangwei , Tang Ping , Jin Nanhui
Published: April 2021

Many types of equipment in the thermal power plant has special risks. Once a safety accident occurs, it often causes special consequences and losses. The indirect losses are difficult to calculate in general due to the special property. In this paper, a calculation model was proposed, considering collateral production impact on upstream and downstream industries, the inconvenience impact on people’s electricity and gas supply, and social security panic by rapidly spreading to media and public opinion. An example of a main steam pipe burst accident in a thermal power plant was analysed. The ratio of indirect economic losses and direct economic losses was obtained. Results showed that the ratio value (35.4) was much higher than the value (4) of general industrial accident loss. The ratio value maybe even much higher if the internal medium of special equipment has strong toxic and harmful effects. It is quite important to make concerted efforts to manufacture, usage, management, inspection, safety monitoring, and scientific supervision, in order to detect and eliminate hidden dangers early and ensure the safe operation of special equipment.
Silicon content prediction of hot metal in blast furnace based on attention mechanism and CNN-IndRNN model
Authors: Gao-peng Wang , Zhen-yu Yan , Hai-peng Zhai , Rui-ji Zheng
Published: April 2021

The stability of blast furnace temperature is an important condition to ensure the efficient production of hot metal. Accurate prediction of silicon content in hot metal is of great significance to the control of blast furnace temperature in iron and steel plants. At present, the accuracy of most silicon prediction models can only be guaranteed when the furnace condition is stable. However, due to many factors affecting the silicon content in hot metal of blast furnace, and there are large noises, large delays and large fluctuations in the data, the previous prediction results are of limited guiding significance to the actual production. In this paper, combined with the actual situation, the convolution neural network is used to extract the furnace condition characteristics, and then combined with the attention mechanism and the IndRNN model to get the prediction results, so that the prediction can better adapt to the fluctuating data set. The experimental results show that the prediction error of this model is lower than that of other models, which provides a new solution for the research of silicon content in hot metal of blast furnace.
Finite Element Analysis and Experimental Study of Metal Shell of GIL
Authors: Mimi Gong , Yantao Zhao , Jiajia Fu , Changlu Luo , Mingdao Sun , Zhiqiang Ma , Fengtao Shi , Zhenkui Gao , Fang Sun , Zhankui Li
Published: April 2021

Mathematical modeling, finite element numerical simulation and experimental measurement of the stress-deformation distribution of the gas-insulated metal-enclosed transmission line shell were carried out. Also, Stress linearization analysis was used to analyze the maximum stress. The results show that the stress is linearly dependent on water pressure and the shell occurs elastic deformation without plastic deformation. The simulated maximum stress of 76.2MPa is fairly in good agreement with the measured one (69.9MPa). The stress linearization analysis results show that the shell well satisfies the environmental safety requirements. The experimental results are consistent with the finite element results.
Analysis of thermodynamic process of water vapor in boiler
Authors: Wang Yarong , Wang Peirong
Published: April 2021

In steam power plant, the working medium used for energy transformation is water vapor. The generation process of water vapor has experienced three stages: pre-heat, vaporization and superheat stage. There are five states in the process. They are sub-cooled liquid, saturated water, saturated liquid-vapour mixture, saturated vapor and superheated vapor. The thermodynamic properties of each state are usually obtained by using water vapor tables and charts. The constant pressure process of water vapor is very common in engineering application. In general, we first determine the state parameters by using charts and tables, and then make relevant calculations according to the first law of thermodynamics.
Effect of a promising CSESE pretreatment on the morphological structure and properties of jute fibers
Authors: Chong Li , Zhiyuan Sun , Hongzhen Fan , Chen Chen , Junjie Li , Qiao Liu , Jianhui Dai , Huazheng Chen , Hongmei Wang , Hongbo Liu , Qingze Jiao , Yanhong Feng , Yongchun Wei
Published: April 2021

Plant fiber has a complex aggregated structure, high crystallinity and a large number of hydrogen bonds, and has low chemical reaction activity. Therefore, in order to improve the reactivity, the plant fiber needs to be pretreated before chemical modification. Therefore, the pretreatment method has an important influence on the chemical modification of plant fibers. In this paper, Jute fibers were successively treated by particular continuous screw-extrusion steam explosion (CSESE). The effects on the morphological ructure, composition, thermal and crystalline properties of jute fibers before and after treated were investigated. Scanning electron microscopy (SEM) showed that the morphological structure changed significantly after CSESE pretreatment, the diameter was smaller, the surface cracks and the specific surface area increased. There was no new functional groups appeared in fourier transform infrared spectroscopy (FTIR). Composition analysis demonstrated that the content of hemicellulose and extractive decreased, but cellulose and lignin increased. The crystallinity of JSE increased from 66.31 % to 70.19 %. X-ray photoelectron spectroscopy (XPS) suggested that the cellulose and lignin content increased. Thermogravimetric analysis (TGA) demonstrated that the initial decomposition temperature of JSE increased from 334.4 to 355.2°C. DMA indicated that the Tg of JSE reduced from 92.6 to 90.0°C. Therefore, for jute fiber, the CSESE pretreatment is an effective and promising pretreatment method for further chemical modification, biofuels and chemical products.
In-situ preparation of MOFs/SiC/PVA-Co-PE nanofiber membranes for efficient photocatalytic reduction of CO2
Authors: Fan Xianwei , Zhao Ran , Hu Haoxuan , Liu Junyi , Nie Yahui , Wang Dong
Published: April 2021

In this paper, we prepared a polyvinyl alcohol-polyethylene (PVA-Co-PE) composite nanofiber membrane catalyst decorated by Fe-MOFs/SiC and completed the photocatalytic reduction of CO2 performance. The results show that the CO2 conversion rate of composite film materials under visible light irradiation is increased by 31 times compared with powdered Fe-MOFs/SiC materials. Through SEM, XRD, BET, FTIR, DRS and other characterization methods, the influencing factors of the photocatalytic CO2 reduction process of the composite nanofiber membrane were investigated. The synergistic effect of Fe-MOFs/SiC and nanofiber membrane photocatalysis is beneficial to electron-hole pairs. The effective separation and strong absorption in the visible light region make it exhibit excellent photocatalytic activity in the photocatalytic CO2 reduction reaction.
Synthesis and Characterization of Eu3+ + 2-thenoyltrifluoroacetone + triphenylphosphine Oxide Ternary Complex
Authors: Shen Qiuxin , Xu Liting , Jiang Yiyan , Zhang Yiping
Published: April 2021

Rare earth europium ion (Eu3+) can emit red characteristic fluorescence under UV excitation and is preferred for the preparation of red phosphors for near-UV white LEDs. In this paper, the effects of solvent, reflux time and preparation method on the preparation of europium ternary complexes were studied with europium ion as the central coordination ion, 2-thenoyltrifluoroacetone as the first ligand and triphenylphosphine oxide as the second ligand. The results showed that the better reaction solvent was anhydrous ethanol and the better reflux time was 8 hours. Both the common synthesis method and the solvothermal method could successfully synthesize the europium ternary complex, and the solvothermal method has a higher yield. The europium ternary complex was characterized by inductively coupled plasma emission spectroscopy, element analysis and infrared spectroscopy, and it was proved that the europium complex could emit a strong characteristic red fluorescence of europium with the structure of Eu(TTA)3(TPPO)2 in 1:3:2 coordination ratio.