bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of Different Harvest Time of Quality of ‘Bashan’ Plum
Authors: Li Benjiao , Li Song , Ma Binrong , Jing Yong , Zhang Zheming , Li Zhijia , Zeng Dequan
Published: June 2020

This paper studied the qualities of ‘Bashan’ plum of 9 different harvest times, changes of several indices were measured periodically at normal temperature after fruit picking. The results showed that from July 10th to 26th, as the harvest time of Bashan crisp plum was delayed, the fruit size gradually increased, acidity decreased and sugar content increased, hardness decreased, and the color of the peel changed from green to yellow-green. According to the standardized production of ‘Bashan’ plum, and the environment and climate conditions in this region, different harvesting dates should be used for different uses of ‘Bashan’ plum, in order to achieve the best fruit, high quality and maximum economic benefits.
Study on Primary Influencing Factors of Flavor Components Produced by Bacillus sp. Isolated from Black Part of Maotai Daqu
Authors: Li Hui , Qu Yang , Tian Wenjie , Wang Xiaoqing , Shi Ben , Tang Yuan , Zhou Hongyu , Bai Yuhe , Cao Lina , Dong Qi , Liu Xinrui , Tian Shuting , Qu Lin , Li Xiuze , Yue Lingfan
Published: June 2020

Microbes are major contributors to the unique fragrance of Maotai liquor, in which Bacillus sp. is recognized as the main flavor-producing strain. However, studies with respect to the importance, sensitivity and optimal ranges of the factors influencing the flavor components secreted by Bacillus sp. have not been reported. In this paper, a thermophilic flavor-producing strain Bacillus sp., isolated from the black part of Maotai Daqu, was chosen as the representative to study how the factors (inoculum size, temperature and incubation time) influenced the production of flavor components (acetic acid, 2, 3-butanediol and ethyl oleate). The optimal combination of factors as well as the quadratic mathematical model of flavor-producing process were obtained through central composite design analysis by batch tests. Results showed that the simulation accuracy of nonlinear equations for the production of three different types of flavor components was 96.00, 87.76, and 90.54%, respectively. Temperature was the most significant factor influencing the production of flavor components, followed by incubation time, and inoculum size showed the smallest impact. In conclusion, the optimized zones of the three factors were as follows: temperature of 38°C∼45°C, incubation time of 13∼15 d, inoculum size of 14∼17%.
The Antibacterial Effect of the Extract of Eupatorium indica Leaves on Two Main Postharvest Diseases of Pineapple
Authors: Weifeng Zhao , Weixiu Yang , Ying Li , Junying Cao , Xiaohuan Yang , Jinhu Ma
Published: June 2020

Phytophthora nicotianae var. Parasitica and Thielaviopsis paradoxa, often occur in pineapple production. In order to explore the bacteriostatic effect of the extract on the pathogen of pineapple disease, and to provide theoretical basis for the application of the extract on the prevention and control of pineapple fungal disease, the antibacterial activity of three extracts of Eupatorium adenophorum against two pathogenic bacteria of pineapple was studied. Two components with antibacterial activity extracted from the leaves of Eupatorium indica leaves were used as “fungicide”. The antibacterial effects of the three extracts on the pathogens of pineapple heart rot and black rot were studied. The results showed that the crude extracts of H, B, and C components at a concentration of 2 mg / ml against pineapple heart rot and black rot pathogens reached 76.14%, 77.94%, 80.40% and 40.15%, 60.50%. The EC90 values of the crude extracts H, B, and C for pineapple heart rot were 4.48, 2.67, and 4.45 mg / ml, respectively. Respectively, the EC90 values for pineapple black rot pathogens were 10.60, 7.17, and 3.27 mg / ml. Relatively speaking, the three kinds of extracts have better antibacterial effects on pineapple heart rot pathogens than pineapple black rot pathogens; B and C two component substances have great potential to prevent and cure pineapple heart rot and black rot.
Effect of Beta-glucosidase on the Aroma of Milky Tea Beverage
Authors: Li Dan , Cao Panrong , Wang Min
Published: June 2020

The bottled milky tea in the market has been extracted and sterilized at high temperature resulting in poor aroma, favour deteriorated and other issues. In order to solve these problems, we added β-glucosidase(β-G) after high temperature sterilization and bottle-filling of milky tea beverage. It is proved to be scientific and efficiency of β-G in improving the aroma of milky tea beverage with black-tea, then the effect is the best when the concentration of β-G was 7.4 U/mL, and the amount of substrate was 100 mL, with 50 °C temperature and pH 5.6, as well as the reaction time is 2 hours. Sure, the innovation of this research is to obtain the effect principle and technology of enhancing aroma of milky tea through the treatment of exogenous β-G, which fundamentally solves the problem of serious loss of aroma air flow of milky tea, and ultimately realizes the maintenance of tea aroma after milky tea list and maximizes the maintenance of original tea flavour. Perhaps due to the improvement of milk tea quality, it can promote the sales of tea beverages.
Adsorption of Chromium (III) on Melamine: Kinetic, Isotherm, Thermodynamics and Mechanism Analysis
Authors: Guo Jing , Chen Ronghua , Zhang Liuying , Shang Qian , Chen Ya , Peng Hao
Published: June 2020

Melamine as single absorbance had been investigated in heavy metal ions removing and it showed good adsorption performance. This paper focused on the chromium (III) remove from wastewater by adsorption with melamine. The results showed that the melamine had a great adsorption surface area of 8.71 m2/g and high adsorption capacity (2843 mg/g) at removal efficiency of chromium (III) (98.63%) within 60 min at n (melamine)/n (chromium)=1.5 and reaction temperature at 90 °C. The adsorption process was described by Langmuir isotherm and the kinetic process was fitted well with pseudo-second-order model. The adsorption process was a spontaneous, endothermic and physisorption process according to the thermodynamic analyzing results. This study provided a good evidence for successful application of melamine in adsorptive removal of chromium (III) from wastewater.
Investigation for Using Properties of Work Wear of Food Practitioner in the Market
Authors: Qiang LI , Jia HAO , Wen LIU , Peng LIU , Yue DAI , Min DUAN
Published: June 2020

Food practitioners are the most close to food, so it is very significant to select suitable work wear during food production to ensure food safety and hygiene. Through investigation about fabric physical and chemical properties, fabric hygiene and clean properties and work clothes basic physical properties of work wear for food practitioner which are frequently seen in the market at present, this paper analyzes whether the work wear in the market have good protection properties, thus providing reference for selection of suitable work wear of food practitioner, and providing reference for food safety and hygienic management of food enterprise. Through investigation, it is found that most work wear have good moisture absorption & quick-drying property, color fastness to bleaching of hypochlorite and soil release. Moreover, the pilling, fracture and micro-particle diffusion to air will not occur easily. However, the work wear of different fabrics are different in antibacterial property, air particle filtering efficiency and electrostatic properties. The food production enterprise can equip suitable work wear according to hygiene requirements in different production processes or different produced food varieties.
No More PET Bottles? Modeling on Single-Serving Water Bottles Future Usage and Environmental Effects
Authors: Ye Jiaming , Cheng Yuqi , Li Jiajin , Chen Haotian
Published: June 2020

Nowadays, there are increasing concerns on the protection of environment. Single-serving bottles, made by polyethylene terephthalate mainly, have caused great damages to the harmonious development of human beings, animals and environment. Hence, this paper measures the impacts of single-serving water bottles ban quantitively by constructing sets of models. This project uses AR(p) model to predict the single-serving water bottles usage in future. The result shows that restrictions or bans on single-serving bottles are essential for our earth’s future. There are two major impacts of water bottles: one is the positive impacts (including reducing environmental pollution, reducing energy cost); the other is the negative impacts (including more soft drinks, health cost, and construction cost). The substitution effect model developed by the authors illustrates the influences of the ban on soft drinks as well as tap water. Moreover, the model was applied in the cases of towns, cities and airport, the biggest difference of which is the population density. Due to the limits of tap water, residents in those area with low density are facing high costs to obtain pure water, which causes much bigger inconvenience comparatively. Besides, this paper builds multi-objective model to find the approximate purifier facilities density from the perspective of maximizing carbon dioxide emissions reduction and minimizing costs. The result shows reducing the substitution effect for soft drinks is a good choice of the optimal condition. Besides, enhancing the price of soft drinks is a better method to reduce the negative impacts of a ban on bottled water. In the end, some suggestions are given regarding the water bottle ban, including enhancing soft drinks’ price, advertising the negative impacts of PET bottles to public.
Effects of Grafting on Photosynthesis of Eggplant Seedlings under Selenium Stress
Authors: Pan Shaokun , Tang Youwan , Xi Chunyi , Lu Ronghai , Wu Yongmei
Published: June 2020

The effects of eggplant seedlings of Fengshengjiaowang grafting with 190-1-8, RS-2, RS-5, Qinqing, wild tomato on the leaf photosynthesis of Fengshengjiaowang were studied by a pot experiment. The results showed that the seedlings of Fengshengjiaowang grafted with 190-1-8, RS-2, RS-5, Qinqing and wild tomato had different effects on leaf photosynthesis after grafting treatments. Among the six treatments, the leaf Pn, Gs and Tr under treatment ungrafted reached the lowest. The leaf Vpdl under treatment Fengshengjiaowang grafted with 190-1-8 reached the lowest, the leaf Ci under treatment Fengshengjiaowang grafted with RS-5 reached the lowest. The leaf Ci for the treatments of Fengshengjiaowang grafted with 190-1-8, RS-2, RS-5, Qinqing, and wild tomato were significantly lower than ungrafted. The leaf Vpdl for the treatments of Fengshengjiaowang grafted with RS-2, RS-5, Qinqing and wild tomato were significantly higher than ungrafted. In conclusion, grafting will affect the leaf photosynthesis of Se content by Fengshengjiaowang grafted with 190-1-8, RS-2, RS-5, Qinqing and wild tomato. In terms of Pn the treatment of Fengshengjiaowang grafted with wild tomato is the best.
The development of organic foods in the world and China’s export trade
Authors: Xiaoxiao Shu , Li Qi
Published: June 2020

With the maturity of consumers’ pursuit of quality of life and the rise in the level of needs, international relations, especially international economic and trade relations, have been severely affected. Green barriers have gradually become an important factor hindering the development of international trade, and China’s organic food exports also face major problems.Therefore, this article analyzes the market conditions and regulations of organic food in the world, studies the demand of organic food producers and exporters in China for the target market, and provides reference for China’s organic food trade.
Hypoglycemic and lipid-lowering effects of extracted from the aerial part of Urtica cannabina L. on alloxan-induced hypergl-ycemic mice
Authors: Long Wenyue , Tang Hongcui , Zhong Xue , Wang Haixin , Wang Huiguo
Published: June 2020

To evaluate the potential effect of Urtica cannabina L. (UC)in type 1 diabetes, we herein investigated the hypoglycemic and hypolipidemic effects and the underlying mechanism of ethanol extracted from the aerial part (AUC)and underground part of Urtica cannabina L(UUC) using alloxan-induced hyperglycemic mice model. The aerial part and underground part of Urtica cannabina L was extracted with 95% ethanol was administered orally (AUC and UUC: at 500, 1600mg/kg body weight) every day for 1 weeks to investigate the anti-diabetic effects in alloxan-induced mices. blood glucose and body weight of the mice were recorded daily, and serum levels of total cholesterol, triglycerides and glycosylated hemoglobin were measured. Compared with thediabetic mice, treatment group affected the weight loss of diabetic mice to different degrees and reduced the blood glucose level. The crude extract of Urtica cannabina L also normalizes lipid metabolism parameters. Compared with the diabetic control group, the administration of the high-dose urticaria high-dose group significantly (P <0.05) reduced the levels of serum triglycerides (P <0.05) and cholesterol (P <0.05). This study suggests that in the mouse model of hyperglycemia caused by diabetic alloxan, Urtica cannabina L has significant hypoglycemic and hypolipidemic activity, these provided scientific basis for the high-value utilization of Urtica cannabina L and healthy consumption.
Automatic Temperature and Humidity Detection and Alarm System for Greenhouse
Authors: Zhao Rui , Lu Likun
Published: June 2020

With the continuous development of agricultural production technology, greenhouses have been widely used in the production of agricultural products. Temperature and humidity are important parameters in greenhouses. The real-time detection and regulation of temperature and humidity in greenhouses plays an important role in crop cultivation. This paper designs an automatic detection and alarm system for greenhouse temperature and humidity based on STM32. The system uses STM32F103C8T6 single chip core module as the microcontroller, uses temperature and humidity sensor DHT11 to obtain temperature value and humidity value, and uses LCD1602 liquid crystal module to display monitoring data and Bluetooth module. Together form a temperature and humidity detection system. Through system function testing, the system can operate stably according to the expected requirements and meet the expected requirements. Finally, an intelligent temperature and humidity monitoring and alarming system that can monitor the temperature and humidity in the greenhouse in real time is realized. The system has the advantages of good stability, high precision and convenient operation, which is of great significance for improving the monitoring and management of temperature and humidity and agricultural production.
Effects of time and height of shading on yield and quality of pineapple
Authors: Weifeng Zhao , Weixiu Yang , Zhiling Ma , Xiaoyan Zhang , Liguo Cha , Shenghui Liu , Yanfang Zhang
Published: June 2020

Effects of time and height of shading on the sunburn rate, yield and quality of pineapples were investigated in order to provide a theoretical basis for high-quality pineapple production. Golden pineapple was used as the material, and three shading times (30 d, 45 d, and 60 d after flower-fading), and the heights of 0 cm, 20 cm, and 40 cm (the distance from the top of the plant) were set. Golden pineapple’s internal and external fruit qualities were measured. The results showed that the incidence of sunburn of pineapple fruits increased with the delay of the shading time, and no differences were found among three heights at 30 d after flower fading. When pineapple plants were shaded at 30 d after flower fading and at height of 0 cm, pineapple fruits showed good external qualities, including larger fruit size, less fruit eyes, less fruit shape index, larger fruit hardness, higher edible rate and good internal qualities, including higher soluble solid content, higher soluble sugar content and lower total acidity. Shading at 30 d after flower fading and at height of 0 cm was suggested in pineapple production.
Optimization model of high-frequency second defense line of generator tripping based on frequency safety constraints
Authors: Hengxian Lin , Kaiyuan Hou , Lei Chen , Deming Xia , Yong Min , Shuang Qin , Bowen Zhang
Published: June 2020

Once the transmission grid of the external UHVDC transmission system has a blocking fault, it will cause high-frequency problems. The adjustment capacity of the system alone often cannot meet the requirements, and the generators need to be tripped in the second defense line of the grid. However, the current tripping method of the high-frequency second line of defense is not systematic. This paper first proposes a simple and practical frequency safety constraint condition. When the system meets the constraint condition, the maximum frequency deviation under a given power disturbance will remain within the set limit. At the same time, based on this constraint condition, a generator tripping optimization model of the high-frequency second line of defense is proposed. The simulation results prove that the tripping solution obtained by solving the model can make the highest frequency and steady state frequency of the system meet the setting requirements, meanwhile, it can reduce the tripping amount and avoid excessive generator tripping.
A Method for Detecting Parasitic Circuits in the Same DC System
Authors: Caiquan Wen , Jiexiong Quan , xin Wei , Junrong Lv , Huashou Chen
Published: June 2020

In the electric power system, The DC power supply system used in substation station in power system is related to the normal operation of primary and secondary equipment in substation, and its importance is self-evident?Therefore, in the early power design of substations, the dual-loop power supply mode is specially designed for some important loads or equipment in order to ensure the reliability of power supply for these important loads?However, due to the construction of lines, maintenance of equipment, equipment failure, and management is not in place, design drawings are missing and other reasons, often lead to some load parasitic loop phenomenon?Because of the existence of parasitic circuit, it will cause some hidden dangers to the DC power supply system?Therefore, the detection of parasitic circuits is also one of the most concerned issues in the field of electric power engineering, which needs further extensive and in-depth study?
A SCADA approach for Micro-grid based on Platform as a Service (PaaS) Delivery Model of Cloud Computing
Authors: Zhuo Di , Yining Gang , Yi Ding , Jianhang Sun
Published: June 2020

Based on the current development of smart grid, this paper makes an in-depth exploration on the interoperability of microgrid platforms, mainly on the interoperability among institutions. Conduct a hierarchical analysis of different requirements to study different levels of interoperability. In this paper, a private hybrid cloud based SCADA architecture is found based on the interoperability of the microgrid platform while ensuring security limitations. Because data collection and critical monitoring are limited by time in the grid, not as critical monitoring and data collection can be accessed by private cloud partners only after being selected. And the main SCADA function is still controlled by the local server, so the cloud architecture is mixed, and this communication is a service delivery model, a model based on cloud computing.
Research on Key Technologies of Intelligent Energy Gateway Based on Fog Computing Technology
Authors: Chengming Jin , Zhi Cao , Xuesong Liu , Honghan Jin
Published: June 2020

The global low-carbon emission reduction pressure increases, the development of new energy technology and the new generation of information and communication technology starts to change the energy consumption pattern. Integrated energy services are getting more and more attention. For this reason, a intelligent energy gateway design method based on fog computing technology is proposed in this paper. Firstly, the construction concept of comprehensive energy internet platform is put forward, and the construction goal, architecture and function of the platform are expounded. Secondly, the key technologies of intelligent energy gateway under the framework of fog computing are summarized, which provides a feasible scheme for the design of integrated energy internet platform. Finally, the design results of integrated energy gateway software and hardware parts are given. The rationality and effectiveness of the scheme under the framework of fog computing are proved.
Research on the Failure Process of Oil Paper Insulation of Surface Partial Discharge under Fluctuating DC voltage
Authors: Bangpeng Xie , Yilun Wan , Lei Tang , Shuyun Wu , Zhan Shi
Published: June 2020

Partial discharge along the surface seriously damages the oil-paper insulation performance and ultimately leads to insulation failure, which greatly reduces the safety and reliability of the converter transformer operation. It is important to understand the failure process of oil-paper insulation under partial discharge along the surface to avoid fault occurrence. In this paper, the failure process of oil-paper insulation under partial discharge of pulsating DC and AC voltage is studied. A partial discharge test platform for oil-paper insulation under pulsating DC voltage was built. The partial discharge test of oil-paper insulation along the extremely uneven electric field was simulated by using the needle plate and column plate discharge model. The oilpaper insulation under two kinds of voltages under the extremely uneven electric field was analyzed in depth. The similarities and differences of the failure process and their causes, the insulation design and operation and maintenance recommendations for preventing flashover under the extremely uneven electric field are proposed.
Research on Safety Protection Control of Equipment Terminal Access based on Power Private Network
Authors: Ou Wang , Wei Li , Chengming Jin , Wenjie Zhang , mingyu Yang
Published: June 2020

In this paper, based on the application requirements of the power industry for the wireless private network, the networking and security protection technology of the power wireless private network are studied. Firstly, it analyzes the necessity of establishing the electric power wireless private network, and then gives the system architecture and technical system of the electric power wireless private network; studies the security risks and Countermeasures Faced by the TD-LTE wireless private network, and analyzes the technical applicability of the TD-LTE wireless private network in combination with the electric power wireless technology policy, so as to provide a reference for the construction of the electric power wireless communication network.
A Novel Sensor Detection Method of Partial Discharge in GIS based on the UHF Electromagnetic Wave
Authors: Hongyi Zhao
Published: June 2020

UHF electromagnetic wave has been widely used in various PD measurements of GIS (gas insulated switchgear) because of its high sensitivity, strong anti-interference ability, large effective detection range, fault location and pattern recognition. In this paper, a new method of detecting partial discharge of pouring hole on GIS insulator is studied. The transmission characteristics of UHF electromagnetic wave are simulated by FDTD. Based on the computer simulation technology (CST), a dipole antenna UHF sensor is developed. Finally, the sensitivity and validity of the sensor are tested on the 110kvgis experimental platform. Compared with the conventional method, the sensitivity of PD detection in GIS is obviously improved.
Preliminarily Realize the Remote Diagnosis of the Running State of the Power Station Unit with Principal Component Analysis Based on Java Program
Authors: Zhang Hui , Niu Xiaochuan
Published: June 2020

For realizing the remote diagnosis of the running state of the power station unit preliminarily, the article accomplishes relevant calculation module for implementing the PCA program, and sets up the data interface of power plant data and PCA module by using the Java program, which completes the calculation and analysis of power plant data in a timely and efficient manner, removes the complexity of manual processing in large dimension data filed and realizes the real-time processing of operation parameters of power plant. Furthermore, the portability of program modules is enhanced and the work efficiency is greatly improved by making the program module executable, which provides a certain reference basis for the monitoring of operation of power plant unit.
Design of Dual MCU Vehicle Control Unit Based on Electric Vehicles to Respond to Control Failure
Authors: Li Jiashun , Li Dan , Xu Ying
Published: June 2020

The Vehicle Control Unit (VCU) is the core component of the entire car. It is responsible for collecting the accelerator pedal signal, brake pedal signal, gear signal and other component signals, and makes corresponding judgments based on the vehicle status to control the next controllers of each component of the layer act to drive the electric vehicle. This article introduces the overall system structure of the electric vehicle and the structural characteristics of the Vehicle Control Unit, analyzes the benefits of the dual MCU Vehicle Control Unit to the electric vehicle, and finally establishes the corresponding detection and response methods when various possible failures occur. The detection and response mechanism uses the main and auxiliary dual MCUs as the control core and cooperates in processing. When the main MCU fails, the auxiliary MCU takes over the control to avoid the uncontrollable safety problems caused by the control of the entire vehicle when the single MCU fails.The dual MCU controller uses the main and auxiliary differentiated design, and the functional design of the main and auxiliary MCUs is based on the functional modularity idea. After the main MCU meets the functions of vehicle control and other functions, the sensor signal detection and other functions are added to the auxiliary MCU. A dual MCU Vehicle Control Unit based on electric vehicle response to control failure is presented.
Operation status evaluation of low voltage distribution network based on PCA- entropy combined weight method
Authors: Yiranyou  , Guo Shishi
Published: June 2020

With the rapid development of smart grid and distribution network intelligence, how to accurately grasp the operating status of the distribution network is an urgent task. Therefore, this paper proposes a method for evaluating the operating status of low-voltage distribution networks based on the PCA-entropy combined weight method. Firstly, the improved principal component analysis (PCA) is used to extract the distribution network evaluation indexes and establish an evaluation index system, which from the four aspects of safety, reliability, quality, and economics. Then model the indexes of each level and calculate the subjective and objective comprehensive weights of the indexes of each level by using the entropy combination weight method. Finally, the feasibility and practicability of the method are verified by comprehensive evaluation of the actual distribution network.
Analysis and Application of Abnormal Electricity Based on Mean Shift Clustering and XGBoost Verification
Authors: Liu Aimin , Sun Feng , Li Wei , Wen Xin , Wang Tong , Cheng Xuke
Published: June 2020

with the gradual development of consumer behavior analysis, abnormal electricity consumption analysis has become a hot Topic in the analysis of mining data. At present, the abnormal power analysis method based on manual verification and judgment is inefficient and has a low hit rate. In this paper, the mean shift clustering algorithm is adopted to cluster the electricity consumption and the fluctuation of electricity consumption respectively and the residents with large electricity consumption and large fluctuation of electricity consumption are selected as suspected abnormal electricity consumption. Then, based on the decision tree model of xgboost, the users suspected of abnormal electricity consumption are filtered twice to realize the automatic study and judgment of electricity consumption behavior and make full use of the massive data resources of the power grid. The value of the source greatly improves the efficiency of verification and helps power enterprises to recover considerable economic losses.
Research on Comprehensive Evaluation Model of Investment Benefits of Transmission and Transformation Projects
Authors: Ge Junkai , Xu Xiaoyu , Chen Wenhan , Shao Jian , Chen Chao
Published: June 2020

With the rapid development of our country’s economy, the demand for electric energy from the whole society is constantly increasing. As the infrastructure supporting power supply, the level of investment and construction efficiency is particularly important for supporting social and economic development and supporting the operation and development of power grid companies. Under these conditions, the comprehensive evaluation of the investment and construction benefits of power transmission and transformation projects is of great practical significance to enhance the management level of China’s power transmission and transformation projects, improve the quality of project construction, and improve the level of utilization of project investment funds.
Research On VSG Comprehensive Control Strategy For Power Grid Voltage Sag
Authors: Xiangyang Yu , Zekai Lu , yan Ding , Chunyang Gao , Shiyan Liu , Dong Liang
Published: June 2020

Virtual Synchronous Generator (VSG) photovoltaic inverter still has the problems of surge current and voltage overcharge when the grid voltage drops. Aiming at the problems mentioned above, the comprehensive control strategy for AC/DC is proposed. The direct current (DC) side adopts the strategy of super-capacitor energy storing and switching Maximum Power Point Tracking (MPPT) derating, the alternating current (AC) side adopts the control strategy of virtual impedance and the vector difference of limited voltage, which are based on the quasi-proportional resonance. Particle swarm optimization (PSO) is used to optimize its parameters because of the difficulties in adjusting parameters of quasi-proportional resonance control by experience. This strategy can track on the voltage with no difference when the voltage is normal, it can also limit the overcharging voltage and the surge current into the demanded range when the voltage drops. Finally, the effectiveness of the strategy proposed in the paper is verified by simulation.
Research on the Design of Building Envelope Based on DeST
Authors: Guan Zhenzhong , Qu Lei , Xu Yanxin
Published: June 2020

School buildings in China have unique features and rules of use. The indoor thermal environment during the study period is very important, but it can be ignored during the summer vacation and winter vacation. It is very difficult to determine the parameters of building envelope through the designer’s experience in order to ensure a good indoor thermal environment and energy consumption level of school buildings. The design of building envelope can be optimized by DeST. In this paper, the design scheme of an experimental building in a school in Beijing is simulated by DeST. Not only were the defects of the first scheme analyzed, but the optimization measures were also proposed. Finally, the goal of low energy consumption and high comfort was achieved.
A multi-sequence method for monthly unit combination optimization using flexible resources
Authors: Cui Dai , Xu Fei , Ge Weichun , Min Yong , Zhou Yunhai , Chen Xiaodong , Zhao Pinchao
Published: June 2020

In order to solve the problem of renewable power curtailment, the authors put forward a multi-sequence monthly unit combination optimization method using flexible resources. In addition, an algorithm is proposed to estimate the capacity of peak load shifting of flexible resources in day-ahead or intraday scheduling. By optimizing various types of flexible resource scheduling in day-ahead or intraday scheduling, the maximum load of the system is lessened, and the limit on the capacity of thermal power units is reduced to improve the system’s ability to accommodate renewable power. In the monthly unit combination optimization model, the total minimum output of thermal power units is introduced into the objective function, which can further reduce the thermal power start-up capacity in the monthly plan to increase the system’s spinning reserve and to expand the renewable power accommodation capacity of the system. Various practical constraints are taken into account. The mixed integer programming and software GLPK are used to program and solve the model. Finally, an example of a provincial grid in north China is given to verify the effectiveness of the proposed method.
Analysis and preventive measures of a shutdown accident caused by high voltage insurance slow melting of a voltage transformer used in excitation system
Authors: Qian Zhunli
Published: June 2020

The voltage transformer (TV) excitation system high-voltage fuse is divided into two cases: one is a short-time fast fuse in the high-voltage fuse, and the voltage on the secondary side of the transformer should drop to zero in an instant. The second is that the high-voltage insurance is slowly fused for a long time, and the voltage on the secondary side of the voltage transformer drops slowly, resulting in the excitation system erroneously strong excitation, the terminal voltage rises, the over-excitation protection action chain reaction, and even the accidental trip. In recent years, the shutdown accidents frequently occur in China due to the high voltage insurance slow-melting of excitation voltage transformers. In this paper, the author analyzes the accident caused by the slow melting of TV high voltage insurance for excitation of one-million-kilowatt units in a company, and puts forward some preventive measures.
Analysis of nondestructive testing method for transverse crack of water wall of Supercritical Boiler
Authors: Zhang Yanfei , Gong Yongqiang , Wang Yingjun , Han Kuo
Published: June 2020

According to the mechanism and characteristics of transverse crack of water wall steel tube, the feasibility, advantages and disadvantages of non-destructive testing methods such as visual testing, magnetic particle testing, ultrasonic testing, eddy current testing, penetrant testing and radiographic testing for transverse crack detection are described. The results show that the array eddy current and far-field eddy current have the advantages of small amount of work, high sensitivity, convenience and high efficiency when they are used to detect the transverse crack of the water-cooled wall steel pipe in service.
Analysis of Stability and Dynamic Model Simulation of Mountain Tractor Rollover
Authors: Yang Hongtu , Xia Changgao , Han Jiangyi , Chen Chen , Zhang Hongdang
Published: June 2020

A rollover model for for predicting the operation of mountain tractors in hilly areas is presented. The quasi-static rollover model and the transient rollover model of the mountain tractor are studied, and the dynamic equations are also derived. The simulation model is set in the Carsim/Matlab Simulink environment, the rollover threshold of the tractor when cornering with a certain lateral acceleration under the angular step condition is analyzed. The anti-rollover control is used when one of the four wheels loses contact with the slope surface. The most significant result is that the model suggests that employment of active rollover control of the wheels may hinder the tractor from rolling on the slope. Thus, it proves the rationality of the model presented.
Research on DC grounding finder to effectively prevent microcomputer protection malfunction caused by one-point grounding of secondary circuit
Authors: Wen Caiquan , Chen Manjiang
Published: June 2020

The problem of protection malfunction caused by one-point grounding of the secondary circuit has received extensive attention, which have been updated in several domestic industrial standards, but the problem of microcomputer protection malfunction due to one-point grounding of the secondary circuit still occurs frequently during operation. According to the analysis, with the comprehensive promotion of microcomputer protection, low-power operating element have been used on a large scale, which makes the grounding resistance of the DC system larger. The relevant parameter setting, principle design and specification requirements of the original DC grounding finder have not been taken into account, which leads to frequent occurrences of secondary equipment malfunction in the DC grounding search process. In-depth analysis of the typical grounding situation showed that the detection resistance value of the existing DC grounding finder is too small, and when both positive and negative electrodes are grounded with high resistance, protection malfunction caused by DC grounding finder may occur. According to the asymmetric characteristics of existing secondary circuits, an asymmetric DC grounding finder was designed, with a strong anti-protection malfunction ability, it was verified by actual measurement that the detection sensitivity of the instrument on ground resistance was improved by more than 50%.
Research and Application of Adjustable Load Measurement Technology Based on Blockchain
Authors: Teng Zhang , Yucheng Ren , Xiaodong Cao , Kang Xie , Junjun Shao
Published: June 2020

In order to promote the synergistic interaction between source network and storage, and enhance the load control capability, the adjustable load measurement technology based on blockchain has become the focus of research at home and abroad. This paper reviews the current research status of block chain technology and its application in declaration and issuance, market supervision, market settlement, load measurement, enhancing mutual trust of market transactions and information security. Distributed ledger from block chain under containerized edge service engine, improved directed and acyclic chart distributed ledger structure and adjustable load execution score three based on distributed ledger data. In this respect, the key and difficult points of technology are summarized. Combined with the current situation of power development demand, power market, electricity price mode, demand response, the possible problems and development trend of adjustable load measurement technology based on block chain are discussed in detail.
Research on Cluster Monitoring and Prediction Platform based on Zabbix Technology
Authors: Peixian Cong , Shenghua Bian , Hongliang Zheng , Baoyu Tang
Published: June 2020

With the rapid development of Internet and computer technology, cluster technology has been widely applied to the explosive growth of network data. With the successful construction of the cluster and the continuous expansion of nodes, the reliability and stability of the cluster itself has become an important factor that cannot be ignored, so various monitoring systems emerge. Based on the above reasons, this paper proposes a real-time monitoring and prediction platform for enterprise users based on Zabbix. The monitoring and prediction platform monitors all kinds of indexes in the cluster in real time and predicts important performance indexes in real time. When monitoring or predicting the abnormal situation, the system can warn the users, which is conducive to the real-time understanding of the cluster operation. The short-term real-time prediction model of cluster monitoring index is introduced in detail in this paper. Finally, the real-time monitoring function of indicators is designed and analyzed based on the prediction model.
A Power Big Data Processing Method for Heterogeneous Data Sources
Authors: Hongjun Du , Wei Li , Ou Wang , Wenjie Zhang
Published: June 2020

With the advent of the era of electric power big data, the volume of electric power data will grow at an unprecedented speed. In this paper, we propose a construction scheme of electric power big data service platform. The platform is positioned as a data sharing, analysis and application platform. Data acquisition, storage, preprocessing, visualization and other aspects can be realized. This paper analyzes the demand of platform construction and designs the platform architecture. At the same time, we introduce the implementation way of big data platform from the aspects of overall platform architecture, functional architecture and technical architecture. And the power big data mining algorithm based on Apriori algorithm is introduced. It can be seen that the platform can provide a reliable analysis and mining platform for data mining in power industry.
A new method for vital sign monitoring using IR-UWB radar
Authors: Beidian Liu , Qixiang Fu , Zhezheng Chen , Wenyu Tao , Zhiqiang Dai
Published: June 2020

Quadrature Demodulation IR-UWB radar is a new form of impulse-radio Ultrawide Band (IR-UWB) radar and it can improve the resolution of distance measurement. This paper focuses on a new method for vital sign – specifically breathing rate and heart rate – from the phase of recorded I/Q signals, using Quadrature Demodulation IR-UWB radar. The results of the experiment show that a better estimation of heart rate can be got from such a new method based on the phase difference.
Research on Train Secondary Pulsation Elimination Method
Authors: Wang Chengtao , Zhang Yuxi , Qiu Ruichang
Published: June 2020

In the train traction system, the single-phase four-quadrant converter achieves the same frequency and phase of the voltage and current on the grid side, but it cannot avoid generating secondary pulse power of the same magnitude as the DC side load. The traditional method is to connect the LC secondary resonance circuit in parallel on the DC side, but the volume and weight of the resonance circuit are relatively large, which reduces the power density, which does not meet the development trend of lightweight trains and the requirements of energy saving. The active filtering method of the secondary pulsation can not only effectively eliminate the secondary pulsation, but also cancel the bulky LC filter, reduce the axle load, increase the passenger capacity, and realize green energy saving.
Modeling and Controller Design of Flyback Converter Operating in DCM for LED Constant Current Drive
Authors: Feng Wei , Chen Yiwen , Jiang Jiahui , Jiang Weiting
Published: June 2020

In power converter, the system model has a significant meaning of the design of the controller and the dynamic characteristics. In this paper, the switching network average method is used to set up the small signal model of flyback circuit, which is operating in discontinuous current mode(DCM). A controller with single zero and single pole is designed based on the small signal model which is set up in this paper. Moreover, the analysis of system stability and dynamic response is proposed. Finally, the system is simulated and verified by a flyback LED constant current drive circuit (220AC input, 0.7A/16W output).
Research and application of PFC controlbased on command extra compensation
Authors: Li Jun , Meng XiangRong , Wendongzhang  , Songgao
Published: June 2020

Based on the analysis of the unit’s PFC(primary frequency control) operation process, combined with the grid performance assessment standards, it was concluded that the inherent delay and inertia of the unit equipment caused PFC action to fail. Aiming at the problem of lack of turbine speed dead-band estimation for the PFC performance evaluation of thermal power units, by constructing the correlation domain between the turbine speed difference and the actual power difference of the unit’s daily operating data, the turbine speed dead-band of the unit was estimated. An optimization control method based on command extra compensation for PFC was proposed to improve the qualified rate of unit’s PFC operation.
Application of Tissue Engineering in Skeleton: A Review on Recent Trends and Advances
Authors: Wang Runtian
Published: June 2020

Due to the biological properties of bone and cartilage, tissue engineering, a new solution with no limit on supply, has gained much attention and many investigations over the past few years. In this review, three basic elements of tissue engineering in skeleton are discussed. Take planting trees as an analogy, scaffolds are the soil providing support, growth factors are fertilizers and pesticides which create a suitable environment together with scaffolds, and cells are the seed whose health and proliferation are the ultimate goals. Both stem cells and terminal differentiated cells like chondrocytes are investigated. Growth factors promoting differentiation, osteogenesis and vasculation are also included. Moreover, many studies focus on manufacturing scaffolds with perfect biological and mechanical properties, in which various structures and components are researched. Besides, 3D bioprinting are utilized for accurate control. Furthermore, studies on engineering and science, in vivo trials, and more available resources have been researched.
CFD analysis of flow field in aromatics extraction unit
Authors: Zhou Chenglong , Chen Tao , Chen Tao , Li Zhipeng , Li Xingfeng
Published: June 2020

The technology of monitoring and tracing the unorganized emissions of VOCs in petrochemical parks is a research hotspot. The characteristics of the wind field at the monitoring point are the key to traceability. Aiming at the Daqing Refinery aromatics extraction equipment, the CFD method was used to simulate the transient flow in the equipment area under 160 ° and 300 ° atmospheric wind. The results show that the flow direction of the local flow field at different positions is different, and the stability of the flow direction is also inconsistent. The local flow field at the monitoring point is related to both the location and the wind direction. When the natural wind changes, the direction and stability of the flow field also change. The flow stability in the vortex region is poor.
Research on Improvement of FQNPP Reactor Protection System Hardware Logic Design
Authors: Xun-Cun LI , Ru-Zhen Yang , Cheng-Jun Gong
Published: June 2020

Fuqing Nuclear Power Plant Reactor Protection System has designed emergency control panel ECP, which is used to deal with the risk of loss of digital automatic protection functions due to common software failure. ECP is designed and implemented by analogy technology, which can bypass the computerized DCS system and use buttons, indicator lights, relays and other devices to achieve system-level protection functions. In practical engineering applications, it is found that the current ECP can not meet the requirements of post-accident control in some specific circumstances. Through the analysis of system design and accident management procedures, two design improvements are listed, compared and analysed, and the optimal improvement is given in this paper.