bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of Radiative Properties of a Multi-particle Cloud with Non-uniform Particle Size Distribution
Authors: Cheng Z M , Wang F Q , Gong D Y , Liang H X , Shuai Y , Li G Q
Published: March 2021

Particle systems involve numerous fields such as combustion, oceanography, photocatalysis, and atmospheric science, among others. In fact, most of these systems were in the form of multi-particle systems composed of different types of particles. In most previous studies, the influence of the type of element on radiative characteristic parameters was not considered, or the effective medium theory was adopted, which led to large calculation errors. In this paper, the differential-integration algorithm developed based on the Mie theory was used to calculate the radiative characteristics (extinction coefficient, absorption coefficient, scattering phase function, asymmetry factor) of a multi-particle system with non-uniform size distribution, and the Monte Carlo ray-tracing (MCRT) method was used to solve the radiative transfer equation (RTE). SiO2 particles and polystyrene particles were investigated and subsequently divided into two categories: submicron particles (χ
>1) and nano particles (χ
>1) according to the size parameter. The radiative characteristics and spectral transmittance of particles with different volume fraction ratios and different particle sizes in the multi-particle system were also investigated. The results of the proposed method were compared to those of experimental tests to verify the accuracy of the algorithm. The maximum relative transmittance error decreased from 30.1% to 0.77%, and the average error decreased from 18.78% to 0.67%.
Analysis and Design of Three-Level Full-Bridge LLC Resonant Converter Based on Pulse Frequency Modulation
Authors: Liu J Z , Zhao Y , Hu P , Chen T T
Published: March 2021

Aiming at the problem of serious switching loss in high-power and high-voltage occasions, the traditional LLC resonant network is difficult to adapt, the DC gain is difficult to obtain intuitively, and the voltage stress on the switch is too high, resulting in large switching losses and difficult selection of the switch. This paper uses a three-level full-bridge LLC resonant converter topology, the First Harmonic Approximation (FHA) is used to analyze the LLC resonant converter gain characteristics, and the parameter design ideas are given. A simulation experiment of a three-level full-bridge LLC resonant converter based on frequency modulation control is presented. The simulation results show that each primary side switch transistor can achieve zero voltage switching (ZVS), the secondary side diode realizes zero current switching (ZCS), and can obtain higher working efficiency, which verifies the feasibility of the design.
Numerical Investigation of the Clocking Effect on the Centrifugal Pump as Turbine
Authors: Jiang W , Liu Z L , Wang Y C , Yang J G , Hou G Y
Published: March 2021

The clocking effect is widely recognized to have an important impact on the function of rotating machinery. The effect of the clocking position on the flow field and the hydraulic performance in a pump as turbine (PAT)with vane diffusers has been investigated and analyzed numerically. The results show the hydraulic performance of the PAT decreasing gradually as the diffuser blade near the tongue. Under optimal operating conditions, the maximum difference in efficiency for different guide vane positions is 2.2%. When the position of the tongue is equidistant from the two diffuser blades, the energy loss of the volute and the diffuser is minimized. And the flow field results prove that the timing position affects the flow field in the volute and diffuser to a certain extent, but has little effect on the impeller. In addition, this may provide ideas for the installation of PAT with guide vanes, and the diaphragm should be as far away as possible from the two adjacent diffuser blades.
Research on Ultrasonic Power Supply Based on Cascade Buck Technology
Authors: Zhang W Y , Zhang C Z , Zhou C H , Zhu Y J , Shu Y H
Published: March 2021

In view of the large voltage harmonics and low power density of the low-power ultrasonic power supply, a low-power ultrasonic power supply based on the cascade buck technology is proposed. The converter of the power supply is composed of two buck units in cascade, and the output of the unit is forward Sinusoidal half-wave DC voltage waveform, and then commutated by the full-bridge inverter every half cycle to output sine wave AC voltage waveform, can significantly reduce the voltage harmonics of the ultrasonic power supply, reduce the inductance of the matching network, and improve the ultrasonic wave Power density. Through the combination of voltage and current phase detection and PI regulator, the tracking resonance frequency is controlled. By analyzing the system structure, working principle and control strategy of the ultrasonic power supply, modeling and simulation are carried out on Matlab / Simulink, and the feasibility and effectiveness of the scheme are verified.
Defect Text Mining Technique and Application in Power Grid Based on the modified Semantic Framework
Authors: Yang T M , Wang Y H , Han Z T , Liang Y , Gao J , Ji X
Published: March 2021

There are mass data that contain important defect texts in the power grid enterprise, and they contain important reliability information. And the efficiency is very low to mine the exact information about the texts especially when the texts are in Chinese. Thus, the defect text mining technique based on the modified semantic framework is proposed. All texts are translated into English and use the text mining model based on the modified semantic framework, the defect texts are divided into a fixed pattern and the digital information can be extracted accurately. Take the transformer as an example, the first step is to establish the ontology dictionary and to separate the sentence and extract the texts’ features. Then, the modified power semantic framework and the semantic slots are defined, and the slots filling method and the semantic framework construction process are discussed, which can automatically perfect the ontology dictionary by merging the word series. Finally, the researches of defect text mining results of statistical reliability are studied, and the results show that the proposed model and method is feasible and effective when applied to automatic classification and statistics of grid defect.
Investigation of Complex Permittivity/Conductivity Distribution by Electrical Tomography
Authors: Wang R C , Gao Y , Wang G J , Li Q P , Wang Q , Wang H G
Published: March 2021

The electrical tomography technology is a multi-phase flow detection technology. This technology has the advantages of non-radiation, non-invasive and visualization, can be widely used in traditional energy field and new energy field. The permittivity and conductivity, as the basic electrical parameters of material, are closely related to the distribution of material in multiphase flow. However, in the actual multiphase flow, due to the non-uniform distribution of permittivity and conductivity in time and space, the accuracy and validity of measuring instruments are challenged. The main target of this research is to investigate the application of electrical capacitance tomography (ECT), electrical resistance tomography with voltage excitation (ERTv) and electrical resistance tomography with current excitation (ERTc) on the multiphase flow with complex permittivity and conductivity distribution. The final objective based on the above research is to provide suitable tomography modual for different multiphase flow process. The experimental results show that ECT is suitable for measuring dry gas-solid fluids. ERTv is better for measuring high water content gas-solid fluids and low conductivity gas-liquid fluids, while ERTc is better for measuring continuous phase conductivity gas-liquid fluids.
Investigation of Temperature Transient Response Characteristics of Ceramic Fuel Rod of Open-Cycled Reactor
Authors: Zhou Y , Lu R B , Zhao F L , Tan S C
Published: March 2021

To investigate the effects of the fuel material property on the temperature safety response characteristics of the new-designed open-cycled reactor with the air as the coolant, the geometric model of the annular fuel rod is built. The parameter model is developed based on the properties of the three types of ceramic material of nuclear fuel including the Uranium dioxide (UO2), Uranium carbide (UC) and Uranium nitride (UN). The temperature transient response rule of the three kinds of fuel rods at the cases of reactor power step increase is obtained based on the fluid-structure coupling method. The temperature transient response characteristics of three types of ceramic fuel rods open-cycled reactor are analyzed. The numerical results reveal that the peak fuel temperature and the average fuel temperature increase significantly with the step increasing reactor power. The response time of the fuel rod with UC is the longest. The peak fuel temperature and the temperature difference of the fuel rod with UO2 are the highest. The relative results can lay the theoretical foundation for the fuel material selection, structure design and the safety analysis of the open-cycled reactor.
Simulation and Experimental Study on the Characteristics of the Gas Cooler in the Simulink CO2 Heat Pump
Authors: Xuan F C , Xie J , Gu Z
Published: March 2021

So as to research impact of inlet temperature of gas cooler on the expression of carbon dioxide hot water unit, the ambient temperature was controlled at 15 °C, and the inlet temperature was adjusted. The exhaust temperature, heating capacity, and system heat exchange capability were calculated. Testing and measuring the change of exhaust temperature, outlet temperature of gas cooler, exhaust pressure, heat exchange capability. Based on simulink simulation tools, a calculation simulation platform of CO2 heat pump water heaters was established, and a test bench of transcritical CO2 heat pumps was built. In the experimental simulation, the inlet water temperature was increased from 15 °C to 40 °C, the simulation result of the exhaust temperature increased by 14.2 °C, the heating capacity decreased by 4.69 kW, the heat pump coefficient decreased by 0.66. In the experimental result, the exhaust temperature increased by 18.7 °C, the heating capacity decreased by 4.31 kW, heat pump coefficient decreased by 0.63. The research results can provide some guidances for the practical application and optimization of transcritical CO2 heat pump system.
Simulation Study of SOFC/GT Combined Cycle System with Turbine Exhaust Recycled to Heat Fuel Cell Air Intake
Authors: Lao X S , Zhang K L , Wang W
Published: March 2021

For the low-temperature SOFC/GT combined cycle system used to recover the SOFC cathode intake air by using turbine exhaust gas circulation, a simulation model of the combined cycle system was established based on the lumped parameter model of SOFC, turbine, compressor and preheater. Some experimental data have verified the validity of the zero-dimensional model of SOFC. The system simulation results show that the air intake pressure caused by the air recirculation does not completely depend on the outlet pressure of the compressor. When the outlet pressure of the compressor is between 0.2MPa and 0.5MPa. The intake pressure of the SOFC will decrease to varying degrees, and it depends on the proportion of the exhaust gas recirculation. The compression ratio is not related to the output power and efficiency of the SOFC. Increase in compression ratio will reduce the output of the turbine, resulting in a reduction in the overall efficiency of the system.
Investigation on the Effect of Dead Time on the Phase of Fundamental Voltage in VSI-PMSM Drive System
Authors: Chen S Z , Jiang J F
Published: March 2021

Both electric vehicle PMSM drive system and grid connected photovoltaic (PV) power generation need voltage source inverter (VSI). The dead time should be set properly when the power switches are turned on and off in the same bridge arm of VSI. During the dead time, the load is out of control, which will cause the abnormal output voltage amplitude and phase. However the influence of dead time on the output fundamental voltage phase has not been paid much attention to and studied. Firstly, in the paper, the phase shift of output fundamental voltage caused by dead time is simulated and analyzed for three-phase VSI - resistance inductance series (RL) load system under several conditions such as variable switching frequency, modulation index, output fundamental frequency and dead time. Secondly, take three-phase VSI - permanent magnet synchronous motor (PMSM) drive system for instance, the simulation analysis of output fundamental voltage phase shift and rotor positioning error caused by dead time are also performed, and an off-line method to compensate the fundamental voltage phase based on αβ coordinate is given. The above work provides a reference for further understanding the influence of dead time on fundamental voltage phase shift in VSI, so as to improve the monitoring and control precision of electric vehicle drive system. The analysis approach can be applicable to the grid connected photovoltaic (PV) power generation PMSM servo system.
Numerical Study on the Coupling Process of Supercritical Heat Transfer and Combustion in the Boiler
Authors: Zhao Z X , Ma C , Li Y Q , Lu D , Lin Y S , Liu Y , Dai C H , Xiao Q , Gou J L
Published: March 2021

The conjugate heat transfer from in–furnace combustion to in-tube supercritical fluid has been numerically investigated in this study. The mathematic model of the conjugate heat transfer process has been constructed. The effects of the heat transfer phenomenons of supercritical fluid in tube and combustion status change in the furnace on the conjugate heat transfer process were analyzed. The results show that the RNG (Renormalization-group) model can better simulate the heat transfer process in the tube and the combustion process in the furnace than the AKN (Abe-Kondoh-Nagano) model. The difference between the two turbulence models for the furnace simulation focuses on the distribution in the high temperature region and the region of the recirculation region.
Research on Drag Reduction Mechanism and Optimization Design of Bionic Jet Flow
Authors: Chen K , Wei Z G , Lin Y S , Zhao X F , Qi X , Huang C H , Yang X H , Zhou H K , Ke H B
Published: March 2021

In the process of sailing, the frictional resistance of underwater objects must be reduced, which is of great significance for improving speed, range and saving energy. Based on the inspiration of the shark breathing process, this paper simplified the water spray process from the external bronchial slit of the shark breathing to the cross-flow lateral jet process. By establishing a numerical model, the influence mechanism of the jet on the flow resistance was studied, and by analyzing different jet velocities, the change of viscous resistance reveals the influence of jet velocity on viscous resistance. The results show that the side jet can reduce the boundary layer on the surface of the object, thereby having a drag reduction effect, and the drag reduction rate can be about 10%. In addition, as the jet velocity increases, the drag reduction effect is enhanced, and at the back of the jet port the vortex is formed, the outlet pressure is reduced, and the drag reduction effect is strengthened. At the same time, the study found that the arc-shaped jet port is more conducive to the reduction of resistance.
Energy Saving Retrofitting of Existing Public Building: A Case Study in Shanghai Area
Authors: Qu Y
Published: March 2021

In order to reduce energy consumption of commercial and public buildings, a series of policies has been implemented in Shanghai area. And retrofitting of inefficient commercial and public buildings serves as one of the main measures. However, there is little study about the effect and economic analysis of energy saving retrofitting, which hinders the popularizing of energy saving retrofitting. Under the sponsorship of the government of Shanghai and World Bank, a typical office building in Changning district of Shanghai was studied about whether it could be retrofitted into a nearly zero energy building through a series of passive and active technologies. During the design stage, based on energy consumption simulations, it was found that nearly zero energy building could save 37.1% energy compared with baseline building. Among the adopted technologies, high-efficiency lamp and photovoltaic system had a relatively higher energy saving ratio, which were followed by high-efficiency cooling and heating system, natural lighting and envelope insulation. Natural ventilation had the least energy saving ratio. By one-year field monitoring of energy consumption after building retrofitting, it was found that the retrofitted building was able to control the CO2 emission per unit area to be less than 25 kg/m2 · a, which met the goal of nearly zero energy building. And the incremental cost per unit area of nearly zero energy building is ￥1553 compared to baseline building. High efficiency lighting is the most cost-effective technology. The conclusions drawn in this study could provide reference for similar retrofitting projects in Shanghai area.
Exploring New Building Energy Saving Control Strategy Application under the Energy Internet of Things
Authors: Qin Y D , Ke J , Wang B
Published: March 2021

This paper makes innovative research on developing a data-driven control strategy under the Energy Internet of Things architecture. On the one hand, the platform aims to provide data representation and interpretable analysis for different stakeholders (end users, construction operators or managers) to realize the flexibility and scalability of the platform; on the other hand, it can improve the thermal comfort and also reduce the power consumption of buildings. However, to process vast amounts of data, it is critical to select appropriate control methods and design optimization issues. Data-driven predictive control (DPC) is a control technology that replaces model-based predictive control (MPC). When applied to complex building operations, MPC is implemented by using the control-oriented data-driven model. The key to DPC technology is the use of CatBoost algorithm, which is highly interpretable and easy to be operated by stakeholders. This paper chooses TDNN, LightGBM, and CatBoost to compare and analyze building energy consumption. Numerical simulation results show that the CatBoost algorithm’s performance is better than other algorithms, and the complexity and implementation cost is significantly reduced.
Active Damping and Passive Control Strategy for Three-Phase LCL Grid-Connected Inverter
Authors: Xie J L , Liao D C , Chen T T , Chen J
Published: March 2021

Compared with traditional controllers such as PI based on classic control theory, the article applies passive control (PBC) theory to the design of three-phase LCL grid-connected inverter controllers. The mathematical model of the system based on Euler-Lagrange (EL) is established, and the damping method of the trap is used to suppress the resonance spikes generated by the system, so that the system meets the requirements of grid connection. The simulation results verify the feasibility of the scheme.
Innovation Control Strategy Simulation Research of Once-through Steam Generator
Authors: Sun Y L , Cheng S Y , Xia G L , li L , Zhang B W
Published: March 2021

The new type of nuclear power plant adopts once-through steam generator (OTSG) which can supply steam to the turbine, control and operation of OTSG is different from the traditional natural circulation steam generator, the control strategy of the traditional natural circulation steam generator is not applicable to OTSG. In order to meet the demand of the general operation of the integrated reactor, the operation control of OTSG is put forward. The paper proposes a double const control strategy that the average temperature of the primary circuit coolant and the secondary circuit steam pressure are kept constant, also proposesa coordinated control strategy considering reactor and turbine as a whole. The control strategy is different the traditional control method. In order to verify the control strategy, simulation experiments are carried out in a full-scale simulator system. The simulation results show that the proposed control strategy of OTSG in integrated reactor to meet the load demand, also can effectively guarantee the dynamic characteristics of pressure steam generator and related parameters of OTSG.
Research on Application of Solar Air Heating in Buildings of Villages in Northern China—Based on Experimental Study
Authors: Liu Z J , Xu W , Zhang L H , Li Z , Li J , Li A S , Feng A R
Published: March 2021

In this paper, a test bench was built to study the thermal performance of three typical air collectors. Based on the test data, this paper conducted a comprehensive study on the physical and economic performance of the solar air heating systems including indoor temperature, solar energy guarantee rate, investment payback period and life cycle cost, and gave recommendations for their applications. The research showed that under the specified air flow rate range, the efficiency of the three typical collectors all reached above 45%. When the flow rate increased twice, the efficiencies of the V-groove collector, S-type spoiler collector, seams penetration collector were increased by 16%, 20%, 19%, respectively. This research recommended the ideal flow rate for solar air heating in China was 36 m3/(h.m2) ~ 54 m3/(h.m2). The simulation results in15 typical cities showed that the solar energy guarantee rate was generally above 20%, and in more than half of cities the solar energy guarantee rate reached 30% or above, with the highest in Lhasa, reached 62%. Economic analysis indicated more than 70% of the cities in northern China have a simple payback period of less than 6 years. The results indicated that solar air heating technology not only has a wide range of adaptability but also yield great financial benefits in northern China. This paper will have a significant impact on guiding the application of solar air heating in rural areas of China.
Analysis and Testing of U.S.-China Key Technology for Charging Interoperability of Electric Vehicles
Authors: Zhang X , Cui J , Zhang W , Ye J D , Li X L
Published: March 2021

At present, China has overtaken the United States to become the world’s largest new energy vehicle market. Due to differences in developmental trajectory, developmental mode, and charging standards, China and the U.S. have common interests and the foundation for cooperation, which can work together for a win-win development. Charging interoperability is the basis for ensuring charging safety and interchangeability of electric vehicles. This study examined and compared the differences between China and the U.S. in the standards for conductive AC charging of electric vehicles. The requirements for a control pilot circuit, proximity circuit, current capacity, and charging-state transition timing were analysed. Hierarchical and layered interoperability test cases based on GB/T 34657 and SAE J2953 series were presented. A dual interface interoperability test system was constructed and used to verify the test method rationale. The results provided a mutual inspection solution for AC charging equipment between China and the U.S. and accelerated global application and promotion of the electric vehicle industry.
Deep-Adversarial-Transfer Learning Based Fault Classification of Power Lines in Smart Grid
Authors: Han J , Miao S H , Yin H R , Guo S Y , Wang Z X , Yao F X , Lin Y J
Published: March 2021

Due to the insufficiency of actual fault samples, the machine learning based fault classification models of the power lines in smart grid are generally trained using the simulated fault samples acquired from software, such as Matlab/Simulink. Yet, the fault features of actual and simulated fault samples are different, and the existed methods might not be valid or accurate enough in classifying the fault types of actual power lines. Thus, a new fault classification model for actual power lines in smart grid based on deep-adversarial-transfer learning is proposed. Firstly, the conditional generative adversarial network (CGAN) is applied for the augmentation of actual fault samples, so as to increase the data amount to some extent. Then, the loss function of convolutional neural network (CNN) is resigned based on transfer learning, and a new fault classification framework based on improved CNN (I-CNN) is proposed. The I-CNN based model is trained using both adversarial and simulated samples, and can make the distrubution of both catergories of samples features closer, thereby achieving to classify the fault types of actual power lines. To verify the method validity, the real-world power line is used for case study. The results show the effectiveness of the proposed method.
Fast Frequency and Phase Lock of Grid-connected TGS Based on FIR Filter
Authors: Ji F , Xu J
Published: March 2021

The thermoelectric generation system (TGS) has many advantages such as clean, no mechanical vibration and high reliability. When TGS is connected to the power grid, it requires that the frequency and phase are same as the power grid. It will take a number of working periods for the response time under the traditional method. A frequency and phase lock method with FIR filter will be introduced in the paper. It is based on the Capture and EPWM module of TMS320F28335. The phase lock can be carried out in one period. And the working frequency of TMS320F28335 is 150MHZ. Therefore, the speed of the whole operation is fast. The experimental results show that the method is feasible.
What’s the Role Of Corn Ethanol Fuel in China: From the Life Cycle Cost View
Authors: Sun Y M , Chung K H
Published: March 2021

China originally planned to use fuel ethanol gasoline nationwide in 2020, and taking corn as an important raw material of ethanol gasoline, this paper analyzed the life cycle cost model of corn fuel ethanol gasoline and traditional gasoline from production to consumption, including internal and external cost calculations. The internal cost is the actual cost of the industry chain, while the external cost is converted into the cost value by examining the environmental impact of pollutant emission levels in each stage of the life cycle of ethanol gasoline production. Based on this model, by selecting the project data of specific regions and manufacturers in China, it can be calculated as follows: The main links affecting the internal cost of ethanol gasoline production are crude oil procurement cost, refinery and ethanol plant construction cost; The main influencing link of external cost is the emission of ethanol gasoline combustion, including the fuel, power and other energy consumption factors in the production of ethanol and gasoline; The cost can be optimized from the perspective of production technology, technological process, energy material consumption and various labor costs. Assuming E10 is used in the whole Chinese market, the empirical results are as follows: among the pollutants produced by the use of ethanol-added gasoline in the whole region, CO2emission reduction is the largest, exceeding 53 million tons, followed by CO and wastewater emission reduction of 1.78 million tons and 1.58 million tons respectively. In terms of the conventional gasoline, the CO emission reduction of about 20% is the largest, followed by about 17% reduction of HC, about 15% reduction of SO2and about 9% reduction of CO2respectively. These results show that the promotion of ethanol gasoline (E10) usage in China has a considerable reduction effect of emission if the availability of raw materials are sufficient. The life cycle external cost of ethanol gasoline is 11.45%, lower than that of conventional gasoline. In 2019, China’s fuel ethanol production capacity was 4.15 million tons, and the actual production was about 3 million tons. Assuming that all of it were used to produce E10 ethanol gasoline, compared with traditional gasoline consumption, the emission reduction benefit of E10 gasoline would be nearly $84.7 million.
New Process of Solidification under Low Temperature of Cation Conductive NaSn2(PO4)3 Synthesized Hydrothermally
Authors: Shimanouchi R , Okubo R , Sato H
Published: March 2021

NaSn2(PO4)3 hard bulk materials were successfully obtained by low-temperature calcination (~600 °C) from hydrothermally synthesized sols without a powder-press or sintering at high temperature. A hydrothermal reaction was performed at 250 °C for 5 h using an aqueous solution of NaOH, an aqueous solution of SnCl4, and H3PO4 as starting materials. The ratio of the starting materials was changed, and the range in which NaSn2(PO4)3 was formed was investigated. As a result, the sample hydrothermally synthesized under the synthesis conditions of Na: Sn: P = 2.75: 0.50: 1.75 was produced as a white sol in a Teflon container. In order to remove Cl from this sol, an immersion treatment with deionized water was performed. After immersion treatment for 3 h, and calcination at 600-900 °C, it was possible to obtain the target substance NaSn2(PO4)3 as a hard bulk material.
Study on Water Model Experimental of Waste Circuit Board Treatment by Top-Blowing Bath Smelting Method
Authors: Zhao X X , Liu Y , Liu X Q , Zhang T A
Published: March 2021

Through the water model experiment of oxygen-enriched top-blowing bath smelting, the effects of factors such as gas flow, lance position and liquid height on the bubble size distribution and liquid splash height during top blowing process of waste circuit boards were studied. The results showed that, the mixing effect worked best when the lance blew in the center of the molten pool. With a suitable increase of the gas flow, the impact of bubble refinement in the molten pool can be optimized. At the same time, the liquid splash, slag entrapment and liquid level fluctuation were aggravated. Appropriately increasing the liquid height can inhibit liquid splash to a certain extent. Considering the effect of bubble refinement and liquid splash height, the optimal experimental conditions of this experimental system were as follows. A straight barrel lance with a diameter of 15mm was installed in the center of the furnace body, the liquid height was 80mm, the lance submersion depth was 40mm, and the gas flow was 7.48Nm3/h.
The Influence of the Clearance on Performance of Compressor
Authors: Geng M F , Chen A Y , Chen D X
Published: March 2021

Cold compressor (CC) was adopted to pump saturated liquid helium to obtain subcooled helium. In the Experimental Advanced Superconducting Tokamak (EAST) system, cold presses were studied and would replace the oil ring pump. The cold compressor processing and installation had been completed, and it had been tested by cold nitrogen gas. For cold compressors, testing at low temperature was essential, but the real working condition of low-temperature helium gas had great risks for large helium cryogenic system. Therefore, an independent cold nitrogen test system was an economical solution. In this work, numerical simulation and quantitative analysis method were used to investigate the flow field around different tip clearances and mass flow by CFD at liquid nitrogen temperature, and they were validated by experiments. When the tip clearance was increased by 0.1mm, the pressure ratio dropped 0.27% and the polytropic efficiency dropped 0.82%. To a certain extent, a larger tip clearance could improve the surge condition and had little influence on the efficiency. Therefore, in the design and operation, the tip clearance could be appropriately increased.
Effects of different ratio of red and blue light on flowering and fruiting of tomato
Authors: Fan Xiaoxue , Yang Yana , Xu Zhigang
Published: March 2021

In this study, the effects of red and blue Light Emitting Diodes (LED) light on flowering and fruiting in the facility cultivation of tomato plants were investigated, tomato plants were subjected to 4 light treatments, dysprosium lamp (as the control, CK) and another three LEDs light with different ratios of red and blue light (RB1, RB2, RB3, R, B). The results showed that under the light with the ratio of red and blue 1:1, the time of first flower and first fruit appeared significantly earlier. The pollen viability and the content of soluble solids sucrose were the highest, and the ratio of sugar to acid is high, which made tomatoes taste great. This study is expected to provide theoretical basis for the high-quality cultivation of tomato seedlings.
Study on the antibacterial activity of dandelion leaf tea
Authors: Li Shuhuan , Chi Xiaojun , Bo Yongheng , Zheng Mengyao
Published: March 2021

In this paper, Shandong dandelion tea was selected as the research object. Its water-soluble and fat-soluble components were extracted by alcohol precipitation method and Soxhlet extraction method, respectively. Antibacterial effects were tested on four different types of strains including Staphylococcus aureus (S.A), Salmonella (SE), Escherichia coli (E. coil) and Candida albicans (CA) in vitro by coating and drilling method. Results showed that dandelion tea powder had certain bacteriostatic effect on Staphylococcus aureus, Escherichia coli, Salmonella and Candida albicans. Water-soluble components mainly had bacteriostatic effect on Staphylococcus aureus, Salmonella and Escherichia coli, and showed the strongest bacteriostatic effect on Staphylococcus aureus but nearly no bacteriostatic effect on Candida albicans. Fat-soluble components had obvious bacteriostatic effect on Candida albicans, but not on Staphylococcus aureus and Escherichia coli.
Study on the biological hazards and control measures of the Dunhuang manuscripts
Authors: Zhang Chao , Lan Xiao-Jun , Bai Xue-Tao
Published: March 2021

The Dunhuang manuscripts are world-renowned precious paper cultural relics, and it is necessary to conduct research on the prevention and control of harmful biological hazards. Taking 6 Dunhuang manuscripts as the research object, through appearance observation, data measurement and literature review, the paper material characteristics are analyzed, and the types of microorganisms on its surface are collected, cultivated and identified, and the cellulolytic ability of the Penicillium strains in them is determined. The spore germination rate of Penicillium at different temperatures was measured, and the effect of low temperature on Penicillium harming paper relics was analyzed. The results showed that the 6 Dunhuang manuscripts were made of hemp paper and thin white paper from the Tang Dynasty to the Song Dynasty. A total of 12 bacteria species and 1 fungus species were isolated and identified. Among them, Penicillium has the ability to decompose cellulose on paper, which is the main harmful microorganism to the Dunhuang manuscripts, low temperature can significantly reduce the germination rate of Penicillium, so low-temperature refrigeration technology can be used to effectively inhibit the damage of Penicillium to paper cultural relics.
The flavor chemistry of pork broth: a review
Authors: Fan Yuting
Published: March 2021

Pork is widely consumed in the world. The unique and attractive flavor is one of the major drivers of consumer liking for pork. Even though the flavor of pork products varies heavily depending on the processing and cooking method, pork broth is very popular in East Asian countries and could serve as a perfect model for studying the flavor chemistry of pork. While quite a number of studies have been carried out on this topic, only a few meet the basic criteria of modern flavor chemistry approaches. By reviewing these publications, 12 volatile compounds, including 4 sulfur containing compounds, 4 aldehydes, 1 alcohol, 1 ester, 1 lactone, and 1 carboxylic acid, were selected as the major aroma active components in pork broth. While the taste of pork broth mainly comes from the basic tastants such as amino acids, organic acids, inorganic minerals, and nucleotides, the role of taste modifiers in pork broth has yet to be investigated. More research is needed to further clarify the flavor chemistry of pork broth.
Exploring the potential pharmacological mechanism of Coix seed on pneumonia based on network pharmacology and molecular docking
Authors: Shen Xingang , Qiu Zhaozhi , Wang Yueqin , Gao Ling , Liu Ying , Liu Yunfeng
Published: March 2021

To explore the potential target and mechanism of action of Coix seed in the treatment of pneumonia by means of network pharmacology and molecular docking. To construct the potential protein interaction network and “component-target” network diagram, GO and KEGG enrichment analysis were performed, then molecular docking was used for verification. In coix seed, 7 effective components and 144 corresponding potential targets were obtained by screening with OB ≥ 30% and DL ≥ 0.18% as thresholds. A total of 5014 pneumonia related targets were obtained, and 90 common targets were obtained.151 nodes and 251 edges were read in the “component-target” visual network diagram. A total of 19 signal pathways with significant differences were obtained by KEGG enrichment analysis. The molecular docking showed that the compounds in Coix seed had higher binding energy with the key proteins that caused pneumonia. This study preliminarily explored the potential action mechanism of coix seed in treating pneumonia by multiple channels and multiple targets, providing scientific basis for clinical application and in-depth study of this decoction piece.
Comparison of activity and components of Sophora flavescens root and seed
Authors: Zhao Wen-Ying , Xiao Wei , Hao Hao-Qi , Zheng Ke , Zhang Dan-Dan , Jin Qing , Zhu Qing-Shu
Published: March 2021

Infectious diseases are amongst the leading causes of morbidity and mortality. The Sophora flavescens root (traditional Chinese medicine “kushen”) is recognized as a strong anti-bacterial and anti-inflammatory Chinese herb, and widely used for clinical application. However, the ever-increasing demand for natural antibacterial agent is fostering the insufficient supply of “kushen”. This study was conducted for the first time to explore the feasibility of Sophora flavescens seed used as a supplement of Sophora flavescens root to alleviate the shortage of “kushen” resources. To accomplish this, the seed and root of Sophora flavescens were extracted by ultrasound-assisted extraction method. The antimicrobial activities of Sophora flavescens seed and root against Escherichia coli, Bacillus subtilis, Micrococcus tetragenus and Proteus species were compared by agar well diffusion method. And the phytochemical constituents from seed and root were analyzed by TLC, chromogenic reaction method, HPLC and GC/MS. The results revealed that different solvent fraction from Sophora flavescens root and seed exhibited different degrees of antibacterial activity. The chloroform fraction, ethyl acetate fraction and anhydrous ethanol fraction of Sophora flavescens root had obvious antibacterial activity. However, the best antibacterial activity of Sophora flavescens seed was achieved with the 80% ethanol extracts. Furthermore, the analysis of phytochemical compositions showed that the antibacterial-activity component profiles of Sophora flavescens seed were different from that of roots. This study clearly reveal that Sophora flavescens seed is unsuitable as a straight substitution of “kushen” due to the differences in their active component, but it has the potential to be used as a promising source of antibacterial agent, which could be utilized in clinical application and pharmaceutical industry, just as Sophora flavescens root.
Effect of spectrum on biological habit of Scopula subpunctaria Herrich-Schaeffer
Authors: Qiao Li , Chen Jun-Hua , Zhang Fang-Mei , Yin Jian , Guo Shi-Bao , Wang Guo-Jun
Published: March 2021

This study aims to screen out the best spectrum possible by study the effect of spectral treatment on biological habit of Scopula subpunctaria Herrich-Schaeffer, and provided a reference for the integrated management of S. subpunctaria. Total 6 groups (90) of adult S. subpunctaria, 9 groups (450) of eggs, 3 groups (300) of pupae, treated with continuous light treatment under room condition from 7:00 pm to 7:00 am every day at 370-375 nm or 420-425 nm, respectively, the control group (45 adult S. subpunctaria) without light treatment. The spawning amount and longevity of adults, the hatching rate of eggs and the eclosion rate of pupae in each group were recorded. The results showed that the total egg quantity and oviposition rate had been effected significantly under illumination treatments. The egg number in every female adult reduced 28.9 and 53.5% under 370~375 nm and 420~425 nm illumination, respectively, compared with the control group, and showed a significant difference level; while the average oviposition rate reduced 11.10 and 15.90% respectively. Meanwhile, the pre-oviposition period and oviposition period were affected by the two illumination treatments. There was no significant effect on the adult longevity of S. subpunctaria nor adult longevity in group feeding nor paired feeding conditions. The egg quantity in groups feeding was higher than that in pairs, and 420~425 nm was reached a significant level contrast to the control deal. The spectral treatments of 370~375 nm and 420~425 nm have effects on the biological parameters of S. subpunctaria, and the latter has significant effects. In conclusion, the light sources can be provided in the tea garden at night (from 7:00 pm to 7:00 am) before the emergence of the adult S. subpunctaria to interfere its population development.
Progress in comprehensive development and utilization of pecan resources
Authors: Wei Hailin , Chen Yuxin , Ouyang Qunwen , Liu Shifeng , Jiang Yao , Lv Fangde
Published: March 2021

The pecan (Carya illinoinensis) is one of the most important woody oil and dried fruit trees in the world. The kernels, peels, husks, inflorescences, leaves, etc. of pecans have many industrial values and are widely used in industrial fields such as chemicals, medicines, pesticides, additives, and vegetable proteins. This article reviews the current process and utilization status of pecans and their nutritional value, including the kernels, skins, shells, inflorescences, leaves, etc. of pecans with shells, and puts forward relevant suggestions for problems in development.
Research on regional environmental legal system to solve toxic and harmful pollution
Authors: Fa Li-Na
Published: March 2021

With the development of economy and the promotion of industrial urban agglomeration, the toxic and harmful substance in Yangtze River Delta has become a difficult problem. Toxic and harmful substances not only include NO2, CO and SO2 in the air which affect people’s health, but also include ammonia nitrogen, petroleum, volatile phenol discharged from waste water caused rivers pollution. From the perspective of regional environmental legal reform, this paper puts forward some suggestions on how to solve toxic and harmful substance pollution by using the principles of law and economics. It is suggested that distinctive and effective legal system measures that corresponding to the local environment should be taken by the regional environmental laws in our country and moreover, in the process of law making, law enforcement and law-abiding, we should pay attention to the important role of public participation. Finally, we actively absorb foreign classic and effective environmental legislation, making the regional environmental legislation norms more and more internationalized.
Reconstruction of the distribution rules of the burden of proof on the causality of environmental tort of toxic and hazardous substances
Authors: Zhang De-Jin
Published: March 2021

The forensic toxicology mainly focus on the determination of the biological damage relationship of external factors through scientific methods. The causation of environmental tort of toxic and harmful substances is on the polluters. However, some judicial practices deviate from the legislative logic. In this study, the contact causality and injury causality, as well as the classification of general causality and specific causality were analysed and discussed. In the result, in the case of scientific uncertainty, the burden of proof of general causality should be assigned to the polluter; in the case of scientific certainty, the burden of proof should be assigned to the injured party. In addition, the burden of proof of specific causality should also be assigned to polluters. This paper is expected to provide a reference for the related research.
Stability analysis of binary transposition algorithms during attacks on text data
Authors: Kryzhevich L S , Dovgal V M
Published: March 2021

Different approaches to using of transposition methods for data protection are examined in the article. The author has conducted comparative analysis of the approaches to increasing strength to protect the text from various attacks when its length and the data amount given per one symbol are raised. Basic criteria of evaluation of the offered methods are marked as well. The increase of the computational complexity in the described approaches is calculated.
Approaches to the application of homomorphic encryption in sensor networks
Authors: Babenko L K , Tolomanenko E A
Published: March 2021

This paper describes the basic principles of the sensor network. The article characterizes the most common types of attacks on wireless sensor networks. The most commonly used protocols of sensor networks are presented. Special attention is paid to schemes of partially homomorphic encryption and fully homomorphic encryption schemes. An approach to the implementation of sensor network protection using the joint use of a fully homomorphic encryption algorithm and a symmetric block encryption algorithm is proposed.
Semi-structured information in the field of artificial intelligence and information security: processing results
Authors: Yusupova N.I. , Smetanina O.N. , Gayanova M.M. , Komendantova N.P.
Published: March 2021

This article is devoted to the semantic analysis of weakly structured information in the field of “Artificial intelligence and information security”. The methodology of this research included two stages and is based on the meta-analysis of existing studies. The received results allow development of further methodological recommendations on semi-structured information and artificial intelligence.
Artificial intelligence tools for analyzing emotionally colored information from customer reviews in the service sector
Authors: Yusupova N I , Bogdanova D R , Komendantova N P
Published: March 2021

On the Internet, you can find millions of service reviews. This information can be useful to support decision-making for both potential customers and for managing a service business It is especially important to consider the emotional tone of such reviews, because emotions can attract or repel potential customers. The article discusses the actual task of the automatic processing of customer reviews and identifying emotionally colored information in it. In this paper we provide the definition of emotions and describe the results of the analysis of their classification. Further on, we identify six main emotions from the customer reviews. As our methodological basis we use a well-known approach for accounting emotionally colored information in customer reviews. This approach made it possible to set the task of automatic analysis of customer reviews, which we applied in this paper.