20 research outputs found
Frequency Characteristic of Resonant Micro Fluidic Chip for Oil Detection Based on Resistance Parameter
Monitoring the working condition of hydraulic equipment is significance in industrial fields. The abnormal wear of the hydraulic system can be revealed by detecting the variety and size of micro metal debris in the hydraulic oil. We thus present the design and implementation of a micro detection system of hydraulic oil metal debris based on inductor capacitor (LC) resonant circuit in this paper. By changing the resonant frequency of the micro fluidic chip, we can detect the metal debris of hydraulic oil and analyze the sensitivity of the micro fluidic chip at different resonant frequencies. We then obtained the most suitable resonant frequency. The chip would generate a positive resistance pulse when the iron particles pass through the detection area and the sensitivity of the chip decreased with resonant frequency. The chip would generate a negative resistance pulse when the copper particles pass through the detection area and the sensitivity of the chip increased with resonant frequency. The experimental results show that the change of resonant frequency has a great effect on the copper particles and little on the iron particles. Thus, a relatively big resonant frequency can be selected for chip designing and testing. In practice, we can choose a relatively big resonant frequency in this micro fluidic chip designing. The resonant micro fluidic chip is capable of detecting 20–30 μm iron particles and 70–80 μm copper particles at 0.9 MHz resonant frequency
Design of Substation Carbon Emission Prediction Model Based on Cloud Model
In order to achieve the goal of energy conservation and emission reduction, all walks of life are taking active actions. Power system, as the main dispatching application of energy, is in full swing in the monitoring and management of carbon emissions and other related studies. The purpose of this paper is to study the design of substation carbon emission prediction model based on the cloud model. First, the basic concepts and numerical characteristics of the cloud model are introduced. Secondly, it introduces the principle of carbon emission prediction method based on cloud model and the common carbon emission prediction method. Combining the real-time substation carbon emission data simulation with the cloud model prediction, the prediction results were compared with the BP neural network, and two average error values were used to measure the prediction results. It was found that the cloud model had a higher accuracy in predicting carbon emission, which verified its feasibility and superiority
Control Strategy of Flywheel Energy Storage System Based on Primary Frequency Modulation of Wind Power
As a form of energy storage with high power and efficiency, a flywheel energy storage system performs well in the primary frequency modulation of a power grid. In this study, a three-phase permanent magnet synchronous motor was used as the drive motor of the system, and a simulation study on the control strategy of a flywheel energy storage system was conducted based on the primary frequency modulation of wind power. The speed and current double closed-loop control strategy was used in the system start-up phase, and the power and current double-closed-loop control strategy were used in the power compensation phase. The model reference adaptive control was used to accurately estimate the speed and position of the rotor. The system compensates for the wind power output by using a wind turbine in real-time and conducting simulation experiments to verify the feasibility of the charge and discharge control strategy. At the same time, it can be verified that the flywheel energy storage system has a beneficial effect on wind power frequency modulation
Control Strategy of Flywheel Energy Storage System Based on Primary Frequency Modulation of Wind Power
As a form of energy storage with high power and efficiency, a flywheel energy storage system performs well in the primary frequency modulation of a power grid. In this study, a three-phase permanent magnet synchronous motor was used as the drive motor of the system, and a simulation study on the control strategy of a flywheel energy storage system was conducted based on the primary frequency modulation of wind power. The speed and current double closed-loop control strategy was used in the system start-up phase, and the power and current double-closed-loop control strategy were used in the power compensation phase. The model reference adaptive control was used to accurately estimate the speed and position of the rotor. The system compensates for the wind power output by using a wind turbine in real-time and conducting simulation experiments to verify the feasibility of the charge and discharge control strategy. At the same time, it can be verified that the flywheel energy storage system has a beneficial effect on wind power frequency modulation
Frequency Characteristic of Resonant Micro Fluidic Chip for Oil Detection Based on Resistance Parameter
Monitoring the working condition of hydraulic equipment is significance in industrial fields. The abnormal wear of the hydraulic system can be revealed by detecting the variety and size of micro metal debris in the hydraulic oil. We thus present the design and implementation of a micro detection system of hydraulic oil metal debris based on inductor capacitor (LC) resonant circuit in this paper. By changing the resonant frequency of the micro fluidic chip, we can detect the metal debris of hydraulic oil and analyze the sensitivity of the micro fluidic chip at different resonant frequencies. We then obtained the most suitable resonant frequency. The chip would generate a positive resistance pulse when the iron particles pass through the detection area and the sensitivity of the chip decreased with resonant frequency. The chip would generate a negative resistance pulse when the copper particles pass through the detection area and the sensitivity of the chip increased with resonant frequency. The experimental results show that the change of resonant frequency has a great effect on the copper particles and little on the iron particles. Thus, a relatively big resonant frequency can be selected for chip designing and testing. In practice, we can choose a relatively big resonant frequency in this micro fluidic chip designing. The resonant micro fluidic chip is capable of detecting 20–30 μm iron particles and 70–80 μm copper particles at 0.9 MHz resonant frequency
RNF7 Facilitated the Tumorigenesis of Pancreatic Cancer by Activating PI3K/Akt Signaling Pathway
RING finger protein-7 (RNF7) functions as a positive regulator in the progression of multiple malignancies. However, the underlying mechanism by which RNF7 contributes to pancreatic cancer (PC) is lacking. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to test the level of RNF7expression in PC cell lines and tissues. The role of RNF7 in PC tumorigenesis was analyzed by Cell Counting Kit-8 (CCK-8). 5-Ethynyl-20-deoxyuridine (EdU), wound-healing/Transwell assays, as well as a subcutaneous tumorigenesis model were constructed to assess the role of RNF7 in PC cells. The association between RNF7 and PI3K/Akt signaling were assessed by western blot and further confirmed by rescue experiments. The PC patients with upregulated expression of RNF7 had poor survival. Overexpression of RNF7 significantly facilitated PC proliferative and migrative and invasive properties in vitro and vivo; however, knockdown of RNF7exhibited the opposite results. Mechanistically, RNF7 promoted PANC-1 and SW1990 cell growth through impacting the activation of the PI3K/Akt signaling pathway. Our data demonstrated that RNF7 promoted PC tumorigenesis via activating the PI3K/Akt signaling pathway and might be regarded as one of the potential therapies to PC
Research on Security Framework of Mobile Application in Dispatch and Control Domain of Power Grid
The rapid development of mobile Internet technology and the wide spread of smart terminals have brought opportunities for the transformation of power grid business model. Compared to the non-real-time information, the real-time and running data of dispatch and control domain is easy to be intercepted and cracked. To solve this problem, this paper presents a new approach to mobile application security framework for the power grid control field. It is to realize secondary encryption by using the method of MD5+AES mixed encryption algorithm and combining the time stamp in real-time data transmission process. At the same time it is to prevent cross-border operations and brute force by using Token authentication and Session technology. China EPRI safety test results show that the application of the framework significantly improves the integrity, safety and reliability of real-time data in power grid control
Realization of interdigitated back contact silicon solar cells by using dopant-free heterocontacts for both polarities
For crystalline-silicon (c-Si) solar cells, the interdigitated back contact (IBC) structure has been long known as an efficient way to approach the theoretical limit of efficiency. However, the complexity of fabricating this kind of devices as well as the high dependence on expensive vacuum systems pose concerns about their commercial potential. Here, we demonstrate a novel c-Si IBC solar cell featuring dopant-free heterocontacts for both polarities, i.e. a solution-proceeded PEDOT: PSS film as hole-transporting layer (HTL) and an evaporated magnesium-oxide film as electron-transporting layer (ETL). Our innovatively buried ETL method provides substantial simplification on the architecture and fabrication of the IBC cells and makes it possible to adapt solution-proceeded HTLs while keeping good passivation in gap regions. The IBC solar cell shows an efficiency of 16.3%, with a promising short-circuit current density (J(sc)) up to 38.4 mA/cm(2). A thorough simulation concerning the influence of pitch size, surface recombination rate (at ETL and gap regions) was conducted, revealing a readily achievable J(sc) of 41 mA/cm(2) and a PCE beyond 22%. Our findings demonstrated a feasibility of using solution method to fabricate high efficiency dopant-free IBC solar cells
Activating and optimizing evaporation-processed magnesium oxide passivating contact for silicon solar cells
Activating and optimizing evaporation-processed magnesium oxide passivating contact for silicon solar cell