Flexible Conversion Research Articles

Research on Market Mechanism of Thermal Power Flexible Transformation to Promote Clean Energy Consumption

By continuously developing a new power system aiming at “double carbon”, the peak shaving pressure of the power system continues to rise and the existing peak shaving ability is slightly weakened. But the historic energy structure in Northeast China has more features of thermal power generation. Therefore, it is urgent to improve the demand for deep peak shaving by a flexible combination of thermal power plants to realize renewable energy consumption. In view of this, this paper analyzes the current power market mechanism in Northeast China, constructs a new energy consumption model for flexible transformation of thermal power, and makes a simulation analysis in the area with wind fire ratio of 1:4. Finally, through flexible conversion of thermal power unit, wind power consumption can be better realized and the problem of wind abandonment can be solved. The research results can provide reference for formulating relevant policies and production models.

Quantum-illumination-inspired active single-pixel imaging with structured illumination.

Quantum-illumination-inspired single-pixel imaging (QII-SPI) or computational ghost imaging protocol is proposed to improve image quality in the presence of strong background and stray light. According to the reversibility of the optical path, a digital micro-mirror device acts as a structured light modulator and a spatial light filter simultaneously, which can effectively eliminate 50% of stray light. Accompanied by a 6 dB gain of detection signal-to-noise ratio under an equivalent loss condition, our scheme only requires a simple and minor modification on the placement of the single-pixel detector based on the original SPI system. Since QII-SPI will obtain almost the same reconstruction results as the passive SPI technology in principle, one can, therefore, adjust the placement position of the detector, without exchanging the relative position of the detector and the light source to realize the flexible conversion of the SPI system from active to passive. Also, this work initially discusses the influence of relative coherence time on Hadamard-based SPI driven by a thermal source. This work brings new insights into the optical path design of the SPI technology, paving the way for the practical application of active SPI in stray light environments.

Mechanical Switch Based Adaptive Fault Ride-through Strategy for Power Quality Improvement Device

Cascaded H-bridge power quality improving device (PQID) has garnered extensive attention for its flexible electric energy conversion and fast voltage response. However, the failure rate of PQID is relatively high due to the use of large numbers of power electronic devices. This paper proposes a mechanical-switch based adaptive fault ride-through strategy for improving the operational stability and power supply reliability of PQID. According to the features of the topology and working principle of PQID, this paper summarized the types of internal faults and analyzed the characteristics of different types of faults. Based on the shortcomings of existing mechanical switches as a bypass method, corresponding adaptive fault ride-through strategies are proposed for different types of faults, and a comprehensive simulation test has been carried out. The results show that the proposed strategy can adaptively ride through unit faults and effectively improve the output waveform quality during the ride through time.

Magnetic-induced conversion between electric quadrupole radiation and quasi dipole radiation at THz band

Based on particle-in-cell simulation and theoretical analysis, we demonstrate the possibility of the realization of the electric quadrupole radiation (EQR) and the quasi dipole radiation (QDR) modes at the THz band from the electrostatic oscillation of the electrons driven by the two-color lasers inside the plasma. Interestingly, an implantation of the external magnetic field will induce the flexible conversion between the EQR mode and the QDR mode. The emission angle, radiation frequency, and radiation field strength of the two radiation modes can be highly modulated by adjusting the intensity of the magnetic field, the frequency of the laser pulses, and the density of the plasma. This provides a new and practical way toward the generation and conversion of the multiple radiation modes, greatly extending the potential for optical manipulation in magnetized plasma.

Migration Measurement of Pins in Postoperative Recovery of the Proximal Femur Fractures Based on 3D Point Cloud Matching

Background and objectives: Internal fixation is one of the most effective methods for the treatment of proximal femur fractures. The migration of implants after the operation can seriously affect the reduction of treatment and even cause complications. Traditional diagnosis methods can not directly measure the extent of displacement. Methods: Based on the analysis of Hansson pins, this paper proposes a measurement method based on three-dimensional matching, which uses computerized tomography (CT) images of different periods of patients after the operation to analyze the implants’ migration in three-dimensional space with the characteristics of fast speed and intuitive results. Results and conclusions: The measurement results show that the method proposed in this paper has more minor errors, more flexible coordinate system conversion, and more explicit displacement analysis than the traditional method of manually finding references in CT images and measuring displacement.

Wide voltage and high gain Dual-Bridge flexible switching anode power supply conversion circuit

Wide voltage and high gain Dual-Bridge flexible switching anode power supply conversion circuit

How Do Sport Parents Engage in Autonomy-Supportive Parenting in the Family Home Setting? A Theoretically Informed Qualitative Analysis.

The purpose of this study was to identify and examine how sport parents engage in autonomy-supportive parenting in the family home setting. A total of 44 parents and children from 19 families were initially interviewed. Data from these families were profiled to identify seven families that adopted a highly autonomy-supportive parenting style. The seven families' data were then examined using a theoretically focused qualitative analysis using the three dimensions of autonomy-supportive parenting. Sport parents engaged in autonomy support (vs. control) through flexible conversations and supporting decision making. The themes of boundary setting and establishing expectations based on values were indicative of structure. The authors found high levels of involvement across contexts. These findings depict the nature and types of social interactions in the family home that created an autonomy-supportive emotional climate, which often extended to sport, providing a foundation for future theoretical development and applied research in sport.

The principle and application effect of DC breaker and arm damping system

Since Zhou Shan voltage source converter multi-terminal HVDC system (VSC-MTDC) is put into operation on July 2014, the flexible conversion and mutual allocation of electric energy between islands are realized, which provides a strong electric energy guarantee for the development of Zhou Shan islands new area. Restricted by the topology of Zhou Shan VSC-MTDC, the converter station cannot entry and exit flexibly and DC fault will induce the stop of Zhou Shan VSC-MTDC. Under this situation, damping system and DC breaker are added. The control strategy is also proposed. Based on the experimental results, It is drawn that the converter station can entry and exit flexibly and DC fault will be located and isolated quickly.

A Review of the Use of GPEs in Zinc-Based Batteries. A Step Closer to Wearable Electronic Gadgets and Smart Textiles.

With the flourish of flexible and wearable electronics gadgets, the need for flexible power sources has become essential. The growth of this increasingly diverse range of devices boosted the necessity to develop materials for such flexible power sources such as secondary batteries, fuel cells, supercapacitors, sensors, dye-sensitized solar cells, etc. In that context, comprehensives studies on flexible conversion and energy storage devices have been released for other technologies such Li-ion standing out the importance of the research done lately in GPEs (gel polymer electrolytes) for energy conversion and storage. However, flexible zinc batteries have not received the attention they deserve within the flexible batteries field, which are destined to be one of the high rank players in the wearable devices future market. This review presents an extensive overview of the most notable or prominent gel polymeric materials, including biobased polymers, and zinc chemistries as well as its practical or functional implementation in flexible wearable devices. The ultimate aim is to highlight zinc-based batteries as power sources to fill a segment of the world flexible batteries future market.

Flexibilization of Biorefineries: Tuning Lignin Hydrogenation by Hydrogen Partial Pressure.

The present study describes an interesting and practical catalytic system that allows flexible conversion of lignin into aromatic or aliphatic hydrocarbons, depending on the hydrogen partial pressure. A combination of experiment and theory shows that the product distribution between aromatics and aliphatics can be simply tuned by controlling the availability of hydrogen on the catalyst surface. Noticeably, these pathways lead to almost complete oxygen removal from lignin biomass, yielding high‐quality hydrocarbons. Thus, hydrogen–lignin co‐refining by using this catalytic system provides high flexibility in hydrogen storage/consumption towards meeting different regional and temporal demands.

An Interlinking Converter for Renewable Energy Integration Into Hybrid Grids

This letter proposes an interlinking converter architecture, which enables flexibly integrating renewable energy into hybrid grids. The proposed converter has one ac port, and two dc ports, offering a flexible solution to integrating various dc, and ac sources, which can also be versatilely configured as a dc-dc converter, a dc-ac inverter, or a dc-dc/ac multiport converter. The general concept of the architecture, its common-mode voltage analysis, and flexible operation modes are detailed in this letter. Experimental tests are performed on an example converter with a dedicated modulation strategy. The test results confirm the concept in terms of flexible conversion, high power density, low leakage currents, as well as controllable power flow.

An interactive dispatching strategy for micro energy grids considering multi-energy flexible conversion based on the three-level optimization perspective

The study considered the optimization problem of micro energy grids (MEGs) participating in a bidding game with a utility energy grid. To begin, multi-level bidding game frameworks made of multi-MEGs were designed at different stages (day-ahead, intra-day, and real-time), and a three-stage optimization model with multiple game status was present in this paper. Secondly, the paper proposed an improved ant colony optimization algorithm based on the adaptive adjustment of pheromone volatile factor and transfer probability. The IEEE37 node distribution system and the eight-node natural gas system are selected for example analysis. The results show that: (1) the proposed multi-level bidding game strategy can establish the optimal scheme of multi-MEGs operation at different stages of day-ahead, intra-day, and real-time; (2) the improved ant colony optimization can consider the differences of the cooperative game and non-cooperative game among different entities, balance the multi-objective appeals of energy supply cost, output fluctuation of a wind power plant (WPP) and photovoltaic power (PV), bidding revenue, and reserve cost, which could help obtain the global optimum solution; (3) the price-based demand response is more effective in converting renewable power into different forms of energy, and in participating in bidding transactions with the utility energy grid. A more liberalized energy market will bring higher bidding revenue for multi-MEGs.

The influence of pressure and equivalence ratio on the NTC behavior of methane

Methane based polygeneration processes in piston engines offer the possibility of a controllable and flexible conversion of energy, to up-convert low value chemicals and to store energy. These processes preferably take place under fuel-rich conditions and at high pressures. Under fuel-rich conditions, there was one experimental report that a distinctive negative temperature coefficient (NTC) behavior occurs in methane oxidation (Petersen et al., 1999). To design a polygeneration process, reliable kinetic models are required to capture the impact of pressure and equivalence ratio variations on reactivity of the gas mixtures. Here, the experimental basis for methane oxidation is expanded to high pressures and very fuel-rich conditions and compared to literature models, both with special emphasis on the NTC behavior. The oxidation of methane/oxygen mixtures at 2 ≤ Φ≤ 20 and pressures ranging from 1 to 20 bar is investigated. The literature reaction mechanisms are assessed with respect to their ability to predict this phenomenon and used to identify reaction pathways. It is found that NTC behavior occurs in a temperature range between 700 and 1000 K and at pressures higher than 5 bar. The lower temperature limit is slightly shifted towards higher temperatures with decreasing equivalence ratio. In addition, the higher the equivalence ratio, the broader the pressure range, in which the NTC behavior is observed. In general, predictions of some models are in good agreement with the experimental data. Reaction path analyses reveal that the competition between oxidation and recombination pathways are responsible for the NTC region in methane oxidation.

In-Situ Energy Dispersive X-ray Reflectivity Applied to Polyoxometalate Films: An Approach to Morphology and Interface Stability Issues in Organic Photovoltaics

Organic solar cells, characterized by a symmetrical regular layered structure, are very promising systems for developing green, low cost, and flexible solar energy conversion devices. Despite the efficiencies being appealing (over 17%), the technological transfer is still limited by the low durability. Several processes, in bulk and at interface, are responsible. The quick downgrading of the performance is due to a combination of physical and chemical degradations. These phenomena induce instability and a drop of performance in working conditions. Close monitoring of these processes is mandatory to understand the degradation pathways upon device operation. Here, an unconventional approach based on Energy Dispersive X-ray Reflectivity (ED-XRR) performed in-situ is used to address the role of Wells–Dawson polyoxometalate (K6-P2W18O62, hereafter K6-P2W18) as hole transporting layer in organic photovoltaics. The results demonstrate that K6-P2W18 thin films, showing ideal bulk and interface properties and superior optical/morphological stability upon prolonged illumination, are attractive candidates for the interface of durable OPV devices.

An approach to dynamically assigning cloud resource considering user demand and benefit of cloud platform

Cloud computing, with the features of flexible resource assignment, timely on-demand service and transparent by-quantity pricing, has been widely applied recently. As a new business service model, cloud platform must be capable of satisfying user demand and enhancing quality of service. Therefore, an excellent resource scheduling scheme is requisite to improve the working efficiency of cloud platform and ensure its stability. To achieve the goal of meeting user demand and maximizing the benefit of cloud platform, a dynamic allocation model for cloud resource, which takes into account requirement of users and benefit of cloud platform, is proposed. On the one hand, the concept of user satisfaction is presented to meet the different requirements of different users on time and cost. And a dynamic pricing model is designed to realize the flexible conversion between time and cost, which can instead serve to ensure quality of service and win customer loyalty. On the other hand, genetic algorithm is employed to schedule cloud resources, which can reduce operating cost, shorten makespan, lessen energy consumption, and ensure load balancing, stability and fluency of cloud platform, in order to maximize the benefit of cloud platform as possible. Finally, the results of 5 comparative experiments show that the dynamic pricing model presented is reasonable and the dynamic resource assignment scheme proposed is feasible and efficient.

A Function Reconfigurable Antenna Based on Liquid Metal

To meet the demands of maritime transportation on ships, including satellite positioning, wireless communication, and radio frequency identification (RFID) for cargo handling management, a function reconfigurable antenna based on liquid metal is proposed in this paper. The antenna is composed of 3-D-printed hollow cavities, a two-step impedance feeding sheet, and two feeding probes. The 3-D-printed hollow cavities contain a big hollow helix cavity, a hollow cone loaded cylinder cavity, four hollow cylinder cavities, and four small hollow helix cavities. By filling the liquid metal into different hollow cavities, reconfigurable functions are generated, including right-handed circular polarization (RHCP), omnidirectional linear polarization (O-LP), pattern reconfigurable circular polarization, and omnidirectional left-handed circular polarization (O-LHCP). To illustrate this, a prototype is fabricated using 3-D-printed photopolymer resin and etching technology. The measurement results agree well with the simulated ones in terms of return loss, radiation pattern, gain, and axial ratio (AR). For the five reconfigurable states, the measured relative bandwidths for |S11| < −10 dB are 44.7%, 41.7%, 30.4%, 28.1%, and 10.8%, respectively, which covers the bands of a global navigation satellite system (GNSS), wireless communication system, and RFID communication system. Attributing to the advantages of its compact structure, flexible conversion, and good performance, the proposed antenna is a good candidate for maritime transportation applications.

Diagnosis and treatment strategy of coronavirus disease 2019 with cardiovascular disease in elderly patients.

Diagnosis and treatment strategy of coronavirus disease 2019 with cardiovascular disease in elderly patients.

A CRISPR-Cas9-mediated domain-specific base-editing screen enables functional assessment of ACCase variants in rice.

A CRISPR-Cas9-mediated domain-specific base-editing screen enables functional assessment of ACCase variants in rice.

Optimal operation of AC–DC distribution network with multi park integrated energy subnetworks considering flexibility

In order to improve the utilisation rate of renewable energy and flexibility of the system, the AC–DC distribution network with multiple park integrated energy subnetwork (PIESN) based on multi-port power electronic transformer (MPPET) is proposed. First, a power-sharing model of interconnected PIESNs based on MPPET is built, in which the port power of MPPET can be controlled. Then the flexibility demand and supply of electricity, heat and cooling are analysed and a flexibility-sharing model among multi-PIESN is established. Multi-energy flexibility conversion mechanism is proposed and the flexibility index is established. Moreover, the optimal operation problem is formulated and solved. The objective function is the comprehensive operation cost, which includes generation cost, energy cost of PIESN, network loss cost, MPPET loss cost, carbon emission cost and electricity storage system operation cost. Finally, simulation on the modified IEEE33 system shows that the proposed model can make the system be in an adequate flexibility, improve the utilisation rate of renewable energy, reduce load shedding and realise the power sharing among multi-PIESNs.

A two-stage optimal coordinated scheduling strategy for micro energy grid integrating intermittent renewable energy sources considering multi-energy flexible conversion

In this paper, a two-stage coordinated scheduling model for dealing with the optimization problem of multiple-energy (power, heating, and cooling) synergistic supply in the micro energy grid (MEG) is proposed. To overcome the uncertainty impact of wind power and photovoltaic power, the scheduling cycle was divided into a day-ahead phase and a real-time phase. Then, the day-ahead forecasting results were taken as random variables for the upper-layer model. The actual value was taken as the realization of random variables for the lower-layer model, including the energy storage revised model and demand response (DR) scheduling model. The cell membrane and chaotic search algorithms were employed to improve the particle swarm algorithm. The “international low carbon park” in China was selected for a case study. The case study showed the following results: (1)The two-stage optimization model and solution algorithm achieved the optimal synergistic supply of multiple energy forms. (2) Power-to-gas could convert the surplus electricity into natural gas, realizing multi-directional energy cascade conversion. (3)MEG could flexibly interact with the upper-grade energy network for obtaining more economic benefits. (4)The price-based DR could smooth the energy load curve and maximize the operation revenue of the MEG by utilizing complementary characteristics of energy prices.