bluuebunny/crossref_metadata_2025 huggingface dataset:
Optical properties of Silica capped Mn doped ZnS quantum dots
Authors: Tomar Stuti , Gupta Suhaas , Mukherjee Samrat , Singh Arun , Kumar Sunil , Kumar Vijay , Choubey Ravi Kant
Published: March 2021

In the present report, silica capped ZnS quantum dots (QDs) have been synthesized using one-step Stober process. The bare Mn doped ZnS samples have been prepared by the co-precipitation method. The samples have then been coated by a SiO2 layer. X ray diffraction have been used to confirm the presence of desired phases and the absence of any impurity phase. The particle size and morphology have been studied through high resolution transmission electron microscopy (HRTEM). The absorption and the emission properties of the bare and the capped samples have been studied through UV-visible and photoluminescence spectroscopy respectively. Fourier-transform infrared (FTIR) spectroscopy was employed to study the band resonances of the samples.
Chiral gravitational waves produced in a helical magnetogenesis model
Authors: Okano So , Fujita Tomohiro
Published: March 2021

We investigate the gravitational wave production induced by
the primordial magnetic fields in a parity-violating magnetogenesis
model. It is shown that the gravitational waves detectable by LISA,
DECIGO or BBO and the magnetic fields strong enough to explain the
blazar observation can be simultaneously produced. The magnetic
fields and the gravitational waves have the same chirality and their
amplitudes are related, which may also be tested by future
observations.
Experimental study on tritium breeding in water-cooled ceramic breeder blanket mock-up under D–T neutron irradiation conditions
Authors: Zhu Qingjun , Chen Wuhui , Bao Jie , Du Hua , Liu Songlin , Huang Kai
Published: March 2021

The accurate assessment of tritium breeding parameters within fusion blankets is crucial for future magnet-confined fusion machines to realize fuel self-sufficiency. Such an assessment can be conducted using the simulation approach with nuclear data of high-fidelity and, most importantly, validated against experimental data. In this paper, we report neutronics experiment studies carried out on a mock-up of the water-cooled ceramic breeder blanket of the China fusion engineering test reactor (CFETR), irradiated at a deuterium–tritium (D–T) neutron source. The mock-up’s nuclear responses to 14 MeV neutrons, including tritium production rates (TPR) and neutron-induced reaction rates, are simulated and validated by experimental results. Redundant measurement techniques are used, including Li2TiO3 pellets for offline TPR measurements and the developed lithium glass detector with a significantly reduced size for online TPR measurements. The validation of the TPR value is complemented by the experimental evaluation of the neutron-induced reaction rates for Au and Zr foils. All experimental results are analyzed using the MCNP-4C code and FENDL-3.0 nuclear data library. The source term for the Monte Carlo simulation is built using a newly-developed method based upon the modeling of the depth profiling of tritium in the tritiated target. The experiments are in good agreement with the simulations; ratios of the calculation to experimental results (C/E) on TPR are found to be 0.97–1.08. The influence of the first wall tungsten armor on the mock-up nuclear responses is also studied.
IOT based corona preventive polycoat with automatic sanitization system
Authors: Sadhu Aishwarya , Raj Yachna , Chatterjee Sumanta
Published: March 2021

Nowadays, due to the pandemic situation people are stressful. They are fighting against this virus by launching various preventive measures such as “PPE kit”, “Sanitizer Machine”, “ELISA test”, etc. with the help of which India recovered 54% from this virus. At the mean time all the workers are highly at risk for the huge amount of economic loss. Focusing on their situation, a new kit model will be generated in India. To bulwark from COVID-19, preventive measures are employed, which is developed cost-effective and medicated fabric-based full body-cover protective sanitizer polycot. In this research paper, we have proposed an IOT based sanitizer polycot in which Sanitizer Fogging Machine using timer will be fixed. As laminated polyester non-woven fabric with polycot found as the material to get the best product, so the sanitize machine will be automatically connected to the polycot. At the mean time timer will help to sanitize it for particular time. So, that the solution does not get wasted. This will not only help the doctors, nurses to protect themselves but also everyone can use it. It can be easily affordable and also hygienic to use.
Wavelet transform analysis of composite signal under multi-source excitation
Authors: Li Cai , Xiaoling Zhu
Published: March 2021

In practical engineering application, the response of mechanical structure may be the superposition effect of vibration source interaction, while the traditional detection method only considers the main vibration source, ignoring other vibration sources will cause analysis error. Therefore, it is of practical engineering significance to study the detection method of compound excitation in mechanical testing. This paper aims to present an extraction method of composite modulation signal under multi-source excitation by wavelet transform. The modulated signal is analyzed by short-time Fourier transform and wavelet transform. The time-frequency analysis results show that the resolution of wavelet can be automatically adjusted at high frequency, and the effect of wavelet is better at high frequency. The key contribution is to establish a method for extracting multi-source excitation signals and to provide certain technical support for the modulated signal under multi-source excitation.
Design of airborne radar Attitude Test System Based on servo drive
Authors: Zhang Yong , Huo Lijun , Xia Tian , Tang Rongjiang , Mu Hailong
Published: March 2021

This paper presents a design method of airborne radar attitude test system based on servo drive, which can realize the closed-loop test of servo system, the separate test of antenna drive module, the separate test of scanner base and the attitude test. The system adopts the attitude angle measurement method based on fiber laser gyroscope as the core, which can realize scanning angle: azimuth ±0.2° and pitch. By decoupling the disturbance and the measured, the small angle attitude algorithm is designed and corrected. The test results show that the scanning accuracy of the attitude determination system can be controlled ±0.2°, and through the modular instrument of PXI bus, the test efficiency and equipment fault maintenance ability of airborne radar can be improved.
Improved design and experimental research of cooperative robot’s manipulator
Authors: Wei Leng , Lei Zhang , Xian Zhang
Published: March 2021

With the proposal of the Made in China 2025 plan, robots have been widely used in aerospace and other fields. In recent years, robots have been applied in aviation manufacturing industry in the way of man-machine collaboration. Manipulator, as an important part of cooperative robot, plays an important role in its work. In this paper, a new type of modular underactuated manipulator is designed based on the structural improvement of the underactuated manipulator. The test platform of the modular underactuated manipulator is built to verify the actual grasping ability of the manipulator. Experiments show that the design of manipulator is reasonable and can meet the requirements of grasping work.
Simulation and optimum design of small fan for animal house by CFD
Authors: Liu Zhaoxia , Xiong Yingqing , Chen Yan
Published: March 2021

In order to improve the aerodynamics performance of the fan in animal house, the extractor for animal house (model: 400-4-2) has been taken as the optimization object, and the Computational Fluid Dynamics (CFD) method was used to analyze the airflow nearby the whole extractor. The FreescaX5 3D scanner was used to collect data and reconstruct 3D model of the prototype fan. Then, the prototype fan model was optimized by CFD simulation to investigate the performance and defects of the prototype fan, and thereby to propose the improvement scheme. The simulation results of flow field near the blade showed that the performance of fan was influenced by the impeller numbers, the bending direction and the blade shape. In the numerical simulation, when the wind speed was used as the evaluation standard, the parameters of the optimized fan are as follows, the blade number is 7, the blade bending direction is forward bending, the blade tip angle and root angle is 9.5° and 58.0° respectively, and the blade cross-section shape is streamlined with small airfoil curvature. The air volume of the optimized fan increased by 3.86% when the optimized fan is compared with the prototype fan at the same power.
Review on chaotic weak signal processing
Authors: Wang Meng Tong , Liu Shu Yong , Cai Ying , Li Si Ting
Published: March 2021

Weak fault signal not only refers to the signal with very small amplitude, but also refers to the signal existing in the background of strong noise. Weak signal detection technology is widely used in communication, radar, magnetism, vibration measurement, medicine and other research fields. Based on the essence of chaos, this paper summarizes the research status of chaos at home and abroad, including the basic characteristics of chaos system, the basic characteristics of chaos, the chaotic dynamics model and the discriminant method of chaos. The different methods of chaotic weak fault feature extraction are analyzed, their advantages and disadvantages are pointed out, and the research trend is forecasted
Study on modal dynamic balance method of bearing rotor system
Authors: Zhou Huimin , Wang Zhan
Published: March 2021

In order to make dynamic balance for bearing rotor system with unbalanced vibration, a modal balancing method for bearing rotor system is proposed. The vibration of the rotor is decomposed into multi-order components according to vibration mode, the unbalanced components are balanced step by step, and the correction amount of each unbalance is solved by establishing a modal matrix equation. Through simulation analysis, it can be seen that under different conditions of speed and unbalance, the amplitude of the rotor after dynamic balace is greatly reduced, and the average vibration is reduced by more than 70%. This method can suppress vibration effectively for bearing rotor system and improve running performance of high speed bearing rotor system.
Research on Robotic Measurement Path Planning for Complex Surface Workpieces
Authors: Mei Zhen , Qi Lizhe , Sun Yunquan , Xu Min
Published: March 2021

Combined with measurement efficiency, measurement accuracy and no interference in the measurement process, this paper proposes a path planning method for a measuring robot for complex surfaces such as blisk. The position planning of robot measurement path is realized based on the surface chord height difference, and the attitude planning of robot measurement path is realized based on the single measured point measurement attitude space(SMPMAS). Finally, the effectiveness of the proposed method is verified by experiments.
Effect of deformation parameters on microstructure of martensitic stainless steel during static recrystallization
Authors: Ren Facai , Si Jun , Xu Jinsha
Published: March 2021

In this paper, the static recrystallization behavior of X20Cr13 martensitic stainless steel was studied based on the hot compression test. The experimental results show that when the strain of the first pass is less than the critical strain of dynamic recrystallization, the main static softening mechanism is static recrystallization. The effects of prestrain, initial austenite grain size, deformation temperature and strain rate on the microstructure during static recrystallization were analyzed in detail.
A novel method for bearing lubrication enhancement via the inner ring groove structure
Authors: Ge Linfeng , Yan Ke , Wang Chao , Zhu Yongsheng , Hong Jun
Published: March 2021

As the bearing rotation speed increases, the efficiency of the jet lubrication is drastically reduced due to the air curtain effect inside bearing cavity. Regarding this, by adding groove structures to the non-contact area of bearing inner ring surface, a novel method which can guide more oil flowing into the bearing raceway was proposed. By numerical simulation, the flow behavior of oil on the bearing inner ring surface was investigated. The results indicate that, compared with the traditional structure, the axial oil flow on grooved inner ring surface was enhanced, and more oil accumulated in the key lubrication area inside bearing cavity. Finally, by lubrication performance experiments, it was proved that the bearing lubrication performance had been improved by adding groove structures on its inner ring surface.
Rolling Bearing Fault Diagnosis Method Based on Improved Deep Belief Network
Authors: Hu Bingbing , Tang Jiahui , Wu Jimei , Liu Jie
Published: March 2021

The issue of classification accuracy for the fault diagnosis model has received considerable critical attention. In this study, an improved deep belief network was developed and applied to fault diagnosis of rolling bearings. Firstly, the forward training part composed of restricted Boltzmann machines (RBMs) is employed to learn the hidden features of vibration data. Secondly, the samples are synthetized by the reverse generation part according to the weight sharing. The noise time-shift layer can significantly enhance the generalization performance of the model, and the synthesized samples can be utilized to supplement the original dataset to enhance the learning efficiency. Experimental results prove that the improved DBN can manifest remarkable superiority in fault diagnosis against other methods.
Numerical study on the effect of CaCO3 ratio on the mechanical properties of CaCO3/PVC composites
Authors: Luo Shijun , Pan Sining
Published: March 2021

The effect of CaCO3 (calcium carbonate) ratio on the mechanical properties of CaCO3/PVC (polyvinyl chloride) composites was studied by numerical simulation in this paper. The representative volume units of CaCO3/PVC Composites with different CaCO3 ratios were established by using the random dropping method. The stress-strain variation of CaCO3/PVC composites with different CaCO3 ratios under tensile or compressive loads was calculated, and the influence of CaCO3 ratio on the stiffness of CaCO3/PVC composites was discussed. Considering the comprehensive effect of calcium carbonate ratio on stiffness and stress-strain, the best ratio of calcium carbonate in PVC is 25%.
Automatic and rapid calibration method for temperature coefficient of fiber grating temperature sensor
Authors: Lu Meng , Zhang Nan , Liu Pan , He Jianjun , Zhou Yabin , Zhu Pingyu
Published: March 2021

Bare fiber Bragg grating (FBG) is packaged by thermal conductive materials and to be used as a temperature sensor. In the oil bath calibration of the temperature coefficient of the FBG temperature, it is difficult to accurately synchronize the single point temperature measurement and the simultaneously record FBG central wavelength using different devices. An automatic, fast and high precision calibration method for temperature coefficient of FBG temperature sensor is proposed. The experimental results show that the temperature coefficient obtained by the proposed method can accurately measure the temperature, and the calibration process is fast and avoids the error caused by manual recording and formula derivation. The system is suitable for rapid calibration of mass-produced FBG sensors.
Stability Test on Power Supply to the Xenon Lamp of Solar Simulator
Authors: Liu Gaotong , Ning Juan , Gu Zhifei , Wang Zeyang
Published: March 2021

In this paper, the stability of the electrical control system structure of the typical solar simulator system is studied. Volt-ampere characteristic tests, light-on tests and system-level irradiance stability tests after light-on of xenon lamps with three power supplies were carried out using the solar simulator (KFTA). The solar simulator test is carried out on the current three mainstream input power supplies respectively. The stability test target of the electrical control structure of the solar simulator system is completed, and the irradiation instability is realized which is better than± 1%.
Electro-hydraulic Composite Emergency Braking System Based on Frequency Reconstruction Control
Authors: Pan Zheng , Yang Xiao , Jing Hui , Li Boyuan , Wang Rongrong
Published: March 2021

For four-wheel independently driven (FWID) electric vehicle (EV), in order to guarantee braking reliability, hydraulic braking system and motor anti-drag braking system are usually used at the same time. In this paper, a novel electro-hydraulic composite braking control strategy is given to solve the distribution problem of braking torque between hydraulic braking torque and motor anti-drag braking torque. The high-frequency part of the desired braking torque is distributed to the motor brake through a high-pass filter so as to fully utilize the fast response characteristics of the motor. Meanwhile, the low-frequency part of the desired braking torque is distributed to the hydraulic brake through a low-pass filter so as to reduce the load of the motor. The cost functions are designed to determine the cut-off frequency of low-pass and high-pass filters. Through the joint simulation of Matlab/Simulink and TruckSim, the braking effect of the electro-hydraulic composite braking is better than that of pure hydraulic braking with no motor to modulate the braking torque.
Guidelines for the computational domain size on an urban-scale VAWT
Authors: Mo Qiuyun , Guan Huisen , He Shengwen , Liu Yanyan , Guo Rongbin
Published: March 2021

Focusing on the H-type vertical axis wind turbines (VAWTs) widely used in urban, the SST k - ω turbulence model was selected to establish a two-dimensional Computational Fluid Dynamics (CFD) model, the moment coefficient (Cm), and power coefficient (Cp) was taken as the evaluation indicators. The CFD model was used in different domain sizes. The simulation results under the sizes were used to investigate the effect of the computational domain size on the numerical simulation results of the aerodynamic performance of the VAWT. Furthermore, a distance from the turbine center to the domain inlet and outlet of 10D (D: diameter of the turbine) each, a domain width of 10D and a diameter of the rotating core of 1.5D are found to be safe choices to minimize the effects of blockage and uncertainty in the boundary conditions on the results. It provides a reference for the selection of the domain size when CFD simulation is implemented in a vertical axis turbine to get its prediction of the performance in the future accurately.
Research on Topic Mining of Medical Surgical Mask Reviews Sold on E-commerce Platform
Authors: Qidi Jiao
Published: March 2021

Since the outbreak of the epidemic in 2020, the development potential of pharmaceutical e-commerce is huge. Mining and studying the review information of e-commerce platform to improve the dimensions of products is an important way for the healthy development of medical e-commerce. In this paper, the review information of medical surgical mask, a hot sales product of medical e-commerce, is extracted. TF-IDF algorithm, dependency syntax and other models are used to mine the topic information contained in the review, and then python is used to analyze the emotional polarity of the review, and finally the emotional assignments of the main review topics are obtained. The results show that consumers have higher satisfaction with the appearance of goods, but lower satisfaction with packaging. On the basis of the research results, corresponding reference suggestions are proposed for medical e-commerce.
Singularity Avoidance Algorithm Based on Bounded Deviation Path Correction Method
Authors: Wang Nei , Li Bin , Lai Qiwei , Xiang Chao , Wu Di
Published: March 2021

Focused on the abnormal problems of path planning when a custom 6-DOF robot goes passed singular points, this paper makes descriptions based on kinematic analysis and dynamic analysis. It is pointed out that linear interpolation should not be simply abandoned but choose joint motion when singularity problems encounters. Instead, this paper suggests a singularity algorithm to modify the interpolated point sequence in the singular interval after a preliminary path planning of the interpolated point sequences, of which the modification method is called “Bounded Deviation Path Correction Method”(BDPC) in this paper. This algorithm can ensure both the accuracy of the end position and the attitude, and finally realizes the effective and reliable motion planning of the manipulator through the singular interval.
Seeking sustainable pathways for fostering agricultural transformation in peninsular India
Authors: Anantha K H , Garg Kaushal K , Petrie Cameron A , Dixit Sreenath
Published: March 2021

Sizable populations in developing countries in Asia and Africa live in dryland ecosystems, and agriculture in these areas faces major challenges including water scarcity, land degradation, poor infrastructure and insufficient access to markets. Natural resource management (NRM) interventions offer an important path to sustainable agricultural practices through increasing resource use efficiency, but true efficacy will only be achievable if these initiatives can be scaled up. This paper explores the impact of farm-scale NRM interventions undertaken in the state of Karnataka, India, between 2005 and 2020. NRM technologies such as soil health management, resource use efficiency and improved crop cultivars were demonstrated in more than 50 000 farmers’ fields. Participatory demonstrations and capacity building initiatives were effectively used to co-create innovations for rapid and wide dissemination, and NRM practices involving the soil-nutrient-crop-water continuum were the subject of large-scale demonstrations. The demonstration fields were divided into treated and control fields, and efforts were made to measure cost of cultivation, irrigation application and crop yield. The soil health management interventions helped to enhance crop yield by 10%–60% over the control plots. Technologies specific to resource conservation have helped to conserve soil moisture, reduce irrigation requirement by 50–300 mm and reduce the cost of cultivation by US$ 150 ha−1. Improved cereal, pulse and oil seed cultivars increased crop yield minimum by 15%. Although these results have a large variability, they consistently showed the effectiveness of integrating NRM practices with crop demonstrations. These results are ideal for sensitizing stakeholders and policymakers to the benefits of adopting science-based approaches to NRM interventions in order to bridge yield gaps and address land degradation, food insecurity and poverty in dryland regions in South Asia and globally.
Influence of Pacific Decadal Oscillation on global precipitation extremes
Authors: Wei Wenguang , Yan Zhongwei , Li Zhen
Published: March 2021

While the influence of the Pacific Decadal Oscillation (PDO) on precipitation has been extensively studied, its influence on precipitation extremes remains not well-known. Based on a series of generalized extreme value modeling experiments, this paper demonstrates some distinct regional patterns of the PDO’s influence on precipitation extremes worldwide. In eastern China, the well-known ‘southern flood (drought) and northern drought (flood)’ pattern in summer corresponds well to the positive (negative) phase of the PDO. In Australia, there tends to be a tripole pattern, with positive correlation between precipitation extremes and the PDO in the central region, and negative correlation in both eastern and western Australia. The precipitation extremes in northwestern Europe and western Russia roughly hold positive correlation with the PDO. These regional patterns of the PDO’s influences are explained via comparative analyses of the atmospheric circulation conditions between cold and warm PDO phases. Certain precipitation extremes tend to be missed or happen more than once during different phases of the PDO at more than 2/3 of stations in a typical region. The cold phase tends to exert more consistent influences than the warm phase in these typical regions. These findings not only indicate different risks of extreme precipitation for the typical regions during different phases of the PDO, but also have important implications for the near-term projection of variable regional climate extremes under global warming.
Economic Analysis of Centralized Energy Storage and Impact on NEM
Authors: Meng Yunfan
Published: March 2021

Energy storage has a broad prospect in the future electricity market. Hornsdale Power Reserve (HPR), the largest battery energy storage system in Australia, was selected as the research case to evaluate the impact of energy storage systems on the National Electricity Market (NEM) operation and its economic benefits. The analysis of HPR includes its performance in the NEM and FCAS markets, its profitability, and its impact on the different markets, thus reflecting the feasibility and superiority of the energy storage system. The results show that energy storage is active in the FCAS market. By comparing the FCAS regulation performance of HPR and the conventional OCGT in South Australia and researching the response to sudden frequency changes, it is found that energy storage has accuracy, speed in regulating frequency, and maintaining system frequency stability. The economic analysis results show that the primary revenue of energy storage comes from the FCAS market. Taking HPR as an example, more than 70% of its electricity sales revenue comes from the FCAS market, especially the Contingency FCAS market. Comparing HPR with wind farms and PV farms of the same power size (100MW), its high IRR, short payback period, and relatively high NPV demonstrate the investment potential of energy storage systems. Optimizing HPR’s energy storage configuration achieves the maximum benefit when its scale expands by 50% (150MW). There will still be huge profits when grown by 100% (200MW), proving energy storage systems’ development potential. Using the economic sensitivity analysis of HPR to find ways to improve the energy storage system’s economic benefits, it can be seen that increasing the participation rate of the FCAS market and improving the technical level of the battery are the effective methods.
Application of Automation Technology in Coal Preparation Technology
Authors: Wei Xiaolong
Published: March 2021

In order to improve the quality of the coal preparation process and realize the automatic control of the coal preparation process, this article takes an intelligent transformation project of a coal preparation plant as an example to analyze the application of automation technology in the coal preparation process. The article introduces the actual situation of a coal preparation plant and the specific application of automation technology, analyzes the research ideas of the coal preparation plant’s automation technology, the automatic transformation, installation and commissioning of the coal preparation process equipment, and analyzes its process test results. It is hoped that this analysis can be helpful to the good application and development of automation technology in coal preparation technology.
Research on Safety Evaluation Technology of Portal Cranes Based On Analytic Hierarchy Process (AHP) Theory
Authors: Li Qin , Ren Li-Xin , Li Guo-Feng , Tong Yao-Ting
Published: March 2021

This paper introduces the present situation of portal crane and the shortcomings of the current standard system, and puts forward a feasible safety evaluation method. Based on the theory of Analytic Hierarchy Process ((AHP)), the safety assessment method of portal crane is studied, and a more perfect method is put forward. The evaluation value D of equipment safety performance obtained by this method can specifically and clearly express the actual status and risk level of equipment.
An Empirical Analysis of the Impact of Government Subsidies on the Innovation of New Energy Automobile Companies before and after the subsidy policy declines
Authors: Lu Ye , Liu Qin , dan Han Ming
Published: March 2021

This article uses 2016 as the time node, divides 2009-2019 into two phases before and after the subsidy policy declines. It uses the panel data of 15 listed companies whose main business of new energy is the production and sales of new energy vehicles. Regression model and panel regression model respectively analyze the relationship between government subsidies and the innovation performance of new energy automobile companies.
A Wind Speed Prediction Method Based on Improved Empirical Mode Decomposition and Support Vector Machine
Authors: Wang Shibo , Guo Yongchao , Wang Yanzhuo , Li Qinghua , Wang Nan , Sun Shumin , Cheng Yan , Yu Peng
Published: March 2021

Based on the complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) and bat algorithm (BA) to optimize the support vector machine, this paper proposed a combined model for short-term wind speed forecasting to predict the wind speed more accurately. Firstly, CEEMDAN was used to decompose the original wind speed time series into a series of subsequences with different frequencies. Secondly, the decomposed subsequences were forecasted by combined model of BA-SVM. Finally, the wind speed forecasting results was achieved by superposing each predicted subsequence. The simulation results suggest that the model improves the prediction accuracy and reduces the error.
Design of lithium-ion battery management system for mine electric vehicle
Authors: Huang Kaifeng , Wang Yong , Feng Juqiang
Published: March 2021

With the continuous improvement on mine equipment automation level and the progress of battery manufacturing technology, Lithium-ion batteries are widely used in mining transportation, monitoring communication and emergency facilities. This paper designs a kind of lithium-ion battery management system for explosion-proof mining electric vehicle according to GB3836-20210 series standard. And the management system takes STM32F103 as the main controller and LTC6811 as the core, using passive equalization strategy to realize battery voltage equalization. The test results show that the maximum error of 100 batteries after equalization is 0.32v, the average error is 0.03v and the maximum error between the monitoring value and the measured value is 0.3v, the average error is 0.0019v, which prove that the management system has high accuracy and effectiveness.
Research on Marine Photovoltaic Grid-connected System Based on Super Capacitor
Authors: Wang Shihao
Published: March 2021

Ships undertake more than 90% of the logistics and transportation of world trade, but shipping also brings about a large amount of pollutant emissions. According to statistics, 30% and 5% of global pollutants NOx and SOx come from ships. With the continuous introduction of new regulations and policies, green and low-carbon has become the current development trend of ships. The application of new energy power generation through inverter control technology to connect to the ship’s power grid is one of the technical approaches, of which photovoltaic power generation technology is representative. Through the review of relevant literature and books, learn the working principles and characteristics of each component of the photovoltaic power generation system, and complete the selection and design of the main equipment of the system according to the needs of ro-ro ships.
Grid-connected microgrid operation strategy and aggregate load characteristics under differentiated power prices
Authors: Piao Zheyong , Li Haiyan , Bin Geng , Jiang Dongxiao , Yang Weilong , Wu Gang , zhang Wenbao
Published: March 2021

In order to master the aggregated load characteristics of the grid-connected microgrid to serve the planning and operation of the distribution network, the operation strategies and aggregated load characteristics of the grid-connected microgrid under the differential power price are studied. This paper investigates the market mechanism of domestic and foreign microgrids and establishes power configuration modes for different types of microgrids. Under the current differentiated distributed power tariff, considering various power tariffs and generation costs, the output strategies and state change paths for different power scenarios are proposed. Based on this, a solution method based on adaptive immune particle swarm algorithm is presented. Through a large number of simulations, the aggregated load characteristics of the grid-connected microgrid are extracted, which provides a reference for the planning, operation and price mechanism of the microgrid and distribution network.
Study on the toxicity of solar cells
Authors: Qi Hu
Published: March 2021

A solar cell is a device that uses the photovoltaic effect to convert solar energy directly into electric energy. It is used in aviation, aerospace, transportation, communication, forestry and other fields. With the increase of solar cell materials in the environment, the potential impact on the environment is also increased. It has attracted wide attention. Solar cell materials mainly include multi-metal compound thin films such as cadmium telluride (CdTe), cadmium selenide (CdSe) and cadmium sulfide(CDS). Moreover, it includes nanocrystalline solar cell materials such as TiO2 and ZnO and Molecular solar cell materials. The toxicity research status of solar cell materials was reviewed from three aspects: materials and organic solar cell materials. The development of this field is prospected.
Analysis on Coupling Structure of Dynamic Wireless Charging in Electric Vehicle
Authors: Lin Zhiqi , Liu Jiaxin
Published: March 2021

The existing electric vehicles use charging piles for charging, which is inefficient and inconvenient, so wireless charging technology has become the research focus. Compared with the traditional charging mode, electric vehicle wireless charging does not need wiring, more convenient, safe and efficient. This paper presents a three-coil compensation optimization scheme. Based on the research of square-square coupling coil, while determining the optimal winding mode of the coil, the magnetic cores of transmitting and receiving coils were selected to analyze the coupling situation according to the magnetic field distribution cloud map, and use the Simplorer Maxwell and ANSYS software simulation, analysis, contrast system coupling way, the purpose is to meet the needs of dynamic charging, solve the problem of the current electric vehicle charging limited.
Construction of power data products based on STP theory
Authors: Bing Cai , Peng Chen
Published: March 2021

Under the background of digital revolution, the level of power grid intelligence and automation has been improved, and a large number of data of various types have been gathered. Through the analysis of multi-source data of power grid, the new profit growth point of power grid enterprises can be mined. In this paper, the “STP theory” is introduced into the power data commodity market. Through the in-depth analysis of the three elements of power data market segmentation, target market selection and market positioning, the power data product types facing different data trading objects, such as government, power grid itself, third-party enterprises and ordinary users, are constructed. This study will provide a basis for grid companies to explore new data business model.
Research on Temperature Distribution of Single Tank Using Molten Salt for Thermal Storage
Authors: Zhang Huiting , Cai Liang , Zhang Xiao , Li Guanghua
Published: March 2021

The temperature distribution of the storage tank with molten salt as the heat storage medium during the discharge process is introduced in the article. In order to analyze the temperature distribution of molten salt in a storage tank and improve the heat exchange effect, the exothermic process of a single thermal storage tank equipped with an immersion heat exchanger was studied. Fluent software was used in the analysis to study the influence of different heat transfer areas, structures and layouts on temperature distribution by means of numerical simulation. The results show that if the heat exchange area is increased, the temperature uniformity and heat transfer speed in the tank will strengthen. By reducing the tube diameter of heat exchanger, the temperature difference in the axial direction can be reduced. When the heat exchanger is arranged above, the temperature stratification in the tank will be improved, and the heat exchange will be more sufficient.
Performance monitoring and verification of a groundwater source heat pump heating system in a greenhouse
Authors: Zhou Meili , Cai Fei , Uenishi Masahisa , Sekine Yasumasa
Published: March 2021

The traditional heating of greenhouse is mainly by burning coal and fuel; this has some disadvantages such as low energy efficiency and high carbon dioxide emissions. As a renewable energy, groundwater source heat pump (GWSHP) has been widely concerned, and its heating application in greenhouse has a significant impact on energy saving and emission reduction. This paper introduces the GWSHP, and establishes a heating system combined with an existing fuel oil heater (FOH) in a horticultural greenhouse in Gunma Prefecture, Japan. The GWSHP bore most of the heat load, and the FOH was only used as an auxiliary heat source at low temperature. A heating cycle operation monitoring was carried out from November to May of the following year, and the fuel oil saving rate and energy saving rate of the system were calculated to be 74.4% and 22.3% respectively. The results show that the combined heating of GWSHP and FOH is energy-saving and environmentally friendly, and can be widely used in areas rich in groundwater.
Study on oscillatory heat transfer performance of single loop pulsating heat pipe
Authors: Zhi Zhuang , Lei Su , Zheng Dingming
Published: March 2021

The heat transfer performance of single loop pulsating heat pipe (PHP) under different filling rates (FR) was studied experimentally. The temperature oscillation characteristics of the outer wall of the tube, the start-up characteristics under different heating power and the heat transfer characteristics between the tube wall and the working fluid are analyzed. The results show that the evaporation section has the uniform temperature characteristic, the uniform temperature characteristic of the condensation section is related to FR and heating power, there is an obvious temperature change in the adiabatic section. At 50% FR, the working fluid is easier to start. At high power, the thermal resistance of phase change heat transfer between the tube wall and the working fluid has an obvious influence on the heat transfer performance, which cannot be ignored.
A numerical analysis on molten droplet hydrodynamics in sodium pool
Authors: Yassin Nassir , Zhang Zhi-Gang , Wu Qi , Wang Fang , Yang Zhi , Rabih Ahmed , Ali Mohsen M. M.
Published: March 2021

The risk and consequences of vapor explosion during severe accidents are among the most critical safety problems to be considered in next-generation sodium-cooled fast reactors. The melt of the core material (corium) may be produced in the event of inadequate core cooling and/or during Loss of Coolant Accident (LOCA) leading to Core Disruptive Accident (CDA). Corium displacement can then lead to powerful fuel-coolant interactions (FCIs). One of the consequences of this molten corium-coolant interaction is that vapor formation and hence explosion may occur. Due to the problem complexity, only hydrodynamic effects of the multiphase system of a single-droplet vapor explosion phenomenon, without heat transfer, is considered. The present study focuses on simulating a molten droplet pre-conditioning (deformation before breakup) through the early stages of the molten fuel coolant interaction. In order to efficiently capture the melt-sodium interfaces and predict droplet behavior with appropriate mass conservation, calculations were conducted using the CFD code of STAR CCM+ for several melt coolant two-phase system configurations. The results demonstrate that the melt properties and velocity are the dominant factors on the melt droplet pre-conditioning behavior.
Studies of Interactions between Water Droplet and Soap Film
Authors: Liang Yuxi , Tian Shihao , Burleigh Brain
Published: March 2021

In this paper, it explored the interactions between water droplet and soap film. Three types of interactions: merging (droplet and film merges after interaction), bouncing (droplet bounces off the film) and passing (droplet pass through the film) are mainly examined, and how the mass and impact velocity of water droplet will affect the film deformation are studied. After understanding the importance of surface tension and Weber number, both simulation and experiment are used to verify the theory and to interpret the phenomena of droplet-film interactions.
Controllable interfacial synthesis of three-dimensional hierarchical graphdiyne multilayer films
Authors: Hao Wenjun , Lu Shan , Chen Zongping
Published: March 2021

Graphdiyne (GDY) is a new type of carbon allotrope. Liquid/liquid interface growth of GDY can be realized in a controllable manner. Herein, three-dimensional hierarchical multilayer GDY films were prepared by polymerization of hexaethynylbenzene at liquid/liquid interface with various thickness. The present approach allows layer-by-layer growth of hierarchical GDY films. The obtained robust GDY multiple layers can be used as support to grow composites which are efficient catalysts for electrochemical reactions.
Numerical study on thermohydraulic behavior in evaporator section of wicked copper-water heat pipe at low superheat
Authors: Zhu Xidong , Dong Yu , Cheng Jianjie , Yao Yao , Bao Jun , Wang Yu , Liu Jinxiang
Published: March 2021

Previous numerical studies have focused on the temperature profiles, flow pattern, heat transfer characteristics and transient behavior of wickless heat pipes. With the increase of heat dissipated power, the heat transfer capacity of the wickless heat pipe is no longer satisfied. Therefore, the research on flow and heat transfer of wicked heat pipe is more meaningful. In this paper, the numerical model of the heat pipe evaporator with a simplified rectangular wick structure was simulated. The present work to be aimed at the numerical model investigating on possible heat transfer performance. The effects of wick thickness, wick porosity, contact angle, single and double layer on heat transfer and flow characteristics were studied. For the wick thickness of 0.25, 0.5 and 1 mm, the 0.5 mm wick exhibits good versatility in heat transfer and flow. The porosity of 0.3 exhibits better heat transfer than that of 0.5, 0.7, 0.9. The value of the Nusselt number of the porosity of 0.3 reaches 142. For the contact Angle of 0, 30, 60, 90 degrees, 30 degrees has better heat transfer performance. Compared with single-layer wick, the double-layer wick can better promote thermal-hydraulic behavior.
Determination of Limited Aritolonchic Acid A Content in Bazheng Granules by Capillary Electrophoresis
Authors: Liu Fang , Liu Haixing , Han Likun
Published: March 2021

The paper investigated the determination of limited aritolonchic acid A content in Bazheng granules by capillary electrophoresis. The buffer was 30 mmol/L borax solution containing 3% ethanol. The voltage was 16 kV and UV detection wavelength was 250 nm. The aritolonchic acid A content in Bazheng granules was 0.267 mg/g(RSD=4.39%)(n=6). The recovery of aritolonchic acid A in Bazheng granules sample was in the range of 83.8%-121.2% (n=5). The average recovery was 103%(n=5). The new method is fit for the determination of limited aritolonchic acid A content in Bazheng granules.
Research on Rice Disease Identification Model Based on Migration Learning in VGG Network
Authors: Qiu Jing , Lu Xiaolei , Wang Xingxing , Hu Xianqi
Published: March 2021

[Purpose]Aiming at the problems of slow speed, over-fitting and unsatisfactory recognition of traditional recognition models, VGG16 convolutional neural network is applied to rice disease identification, and the knowledge learned by VGG16 model is transferred to rice disease identification by means of migration learning method to construct the recognition model. [Method] The classifier uses linear discriminant analysis by setting different learning rates to fine tune the network parameters. Using image processing technology to expand the disease image set, according to the disease characteristics, the sample is divided into 10 types of diseases such as rice blast, sheath blight, rice smut and bacterial blight, and 90% of each sample is randomly selected as the training set. 10% of the samples were used as test sets, and the samples were trained using the 10-fold cross-validation method. During the simulation training, the other two methods were compared and analyzed. [Result] The experimental results show that the accuracy, balance F score and prediction speed of the disease recognition model using parameter trimming and linear discriminant classifier are higher than the other two recognition models. The average correct rate is 97.19%, the equilibrium F score is 96.75%, and the prediction speed is 175 samples per second; from the performance analysis of the model, the accuracy rate did not show large fluctuations. After 100 trainings, the training and prediction accuracy rate reached 96%, the loss rate showed a gradient downward trend, and the change was relatively stable; The 10 types of disease samples were predicted, and the average accuracy was 97.08%, the recovery rate was 96.22%, and the F1-score value was 96.75%. [Conclusion] The method has the characteristics of high accuracy, strong generalization ability, good robustness and small loss rate. This provides reference and reference for plant disease identification research.
Plasma resonance ultraviolet absorption spectroscopy of gold nanorods
Authors: Li Huiqin , Yan Shaotian , Wu Lihua , Dou Shumei , Ren Xinyue
Published: March 2021

Au nanorods were prepared by seed growth method. Based on the local surface plasmon resonance (SPR) absorption spectra of gold nanoparticles, the formation and growth kinetics of gold nanorods were observed and studied in real time. The effects of temperature and reaction time on the growth process of gold nanorods were emphatically investigated. It was found that the shift of SPR UV-vis absorption peak was closely related to the experimental conditions The influence factors and mechanism of SPR absorption peak shift are discussed. It is concluded that the moving direction of SPR peak is the result of the competition of particle size and charge transfer.
Predicting of Ship Magnetic Field Underwater Based on Grey Theory Model
Authors: Wang Pengzhong , Gao Junji
Published: March 2021

Based on the grey theory DGM (1,1) model, the ship magnetic field at different depths is predicted. COMSOL is used to simulate the ship’s magnetic field, and the simulated magnetic field value is applied to the established model. The gray model is used to predict the ship’s underwater magnetic field at different depths, which verifies the effectiveness of the gray prediction model.
Inland water green smart power pusher
Authors: Xie Yuhong
Published: March 2021

At present, the auxiliary ships for inland waterway operations mainly use diesel as fuel, and a large amount of polluting gas is emitted in the inland waterway, which seriously affects the air quality of cities along the waterway. In order to solve the impact of the current inland waterway auxiliary ships on the environment, this work has designed a new energy intelligent pusher for inland rivers and lakes. The pusher uses electric energy as an energy source. This work is mainly composed of power supply system, container battery rapid replacement system, ship slow contact system, ship positioning and anti-collision system. Under the joint cooperation of all systems, the intelligent jacking of inland rivers and lakes and the rapid battery replacement are completed, and finally it is green, Intelligent and efficient operation effect.