The reactive power optimization of an active distribution network can effectively deal with the problem of voltage overflows at some nodes caused by the integration of a high proportion of ...distributed sources into the distribution network. Aiming to address the limitations in previous studies of dynamic reactive power optimization using the cluster partitioning method, a three-stage dynamic reactive power optimization decoupling strategy for active distribution networks considering carbon emissions is proposed in this paper. First, a carbon emission index is proposed based on the carbon emission intensity, and a dynamic reactive power optimization mathematical model of an active distribution network is established with the minimum active power network loss, voltage deviation, and carbon emissions as the satisfaction objective functions. Second, in order to satisfy the requirement for the all-day motion times of discrete devices, a three-stage dynamic reactive power optimization decoupling strategy based on the partitioning around a medoids clustering algorithm is proposed. Finally, taking the improved IEEE33 and PG&E69-node distribution network systems as examples, the proposed linear decreasing mutation particle swarm optimization algorithm was used to solve the mathematical model. The results show that all the indicators of the proposed strategy and algorithm throughout the day are lower than those of other methods, which verifies the effectiveness of the proposed strategy and algorithm.
Complete and efficient detection of unknown targets is the most popular application of UAV swarms. Under most situations, targets have directional characteristics so that they can only be ...successfully detected within specific angles. In such cases, how to coordinate UAVs and allocate optimal paths for them to efficiently detect all the targets is the primary issue to be solved. In this paper, an intelligent target detection method is proposed for UAV swarms to achieve real-time detection requirements. First, a target-feature-information-based disintegration method is built up to divide the search space into a set of cubes. Theoretically, when the cubes are traversed, all the targets can be detected. Then, a Kuhn-Munkres (KM)-algorithm-based path planning method is proposed for UAVs to traverse the cubes. Finally, to further improve search efficiency, a 3D real-time probability map is established over the search space which estimates the possibility of detecting new targets at each point. This map is adopted to modify the weights in KM algorithm, thereby optimizing the UAVs’ paths during the search process. Simulation results show that with the proposed method, all targets, with detection angle limitations, can be found by UAVs. Moreover, by implementing the 3D probability map, the search efficiency is improved by 23.4%–78.1%.
Enterocytozoon hepatopenaei (EHP) infection has seriously affected prawn culture globally. The symptoms of the infection are not apparent, and traditional detection methods are time consuming and low ...in accuracy. We developed a new onsite rapid testing device (size 18.8 × 16.7 × 6.6 cm3) for EHP based on magnesium pyrophosphate precipitation and facilitated by loop mediated isothermal amplification (LAMP). The design and fabrication of the device enables efficient light absorbance. The device has a highly sensitive detector, high-precision thermal controller, and humanized touch screen. The temperature control precision of the device is 0.2–0.3 °C at 60 °C, 63 °C, and 65 °C. The coefficients of variation values (CVV) of the luminous power in one channel at light on and off were found to be 0.0097 and 0.0014, respectively, within 1 h. The CVV of the background, luminous power, and values of eight PCR tubes filled with pure water were all less than 5%. In the EHP experiment, eight samples (including seven positive and one negative) confirmed the effectiveness of the device, and four positive and four negative samples verified whether cross-contamination exists. Among them, the rise time of the curve was about 15 min. These results assert that the developed device exhibits enhanced stability and uniformity and has excellent performance with high sensitivity, good specificity, and low testing time. Moreover, the optimal and minimum absorbance range was 555–655 nm for monitoring the production of LAMP.
A new onsite rapid testing device for pathogen has good stability, uniformity and reliability which is integrated with light module, detector, thermal controller and human interface module, the qualitative result can accurate judgment in 30 min. Display omitted
We present optical spectroscopic and photometric observations of the nearby type Ic supernova (SN Ic) SN 2014L. This SN was discovered by the Tsinghua-NAOC Transient Survey (TNTS) in the nearby ...type-Sc spiral galaxy M99 (NGC 4254). Fitting to the early-time light curve indicates that SN 2014L was detected at only a few hours after the shock breakout, and it reached a peak brightness of MV = −17.73 0.28 mag (L = 2.06 0.50 ×1042 erg s−1) approximately 13 days later. SN 2014L shows a close resemblance to SN 2007gr in the photometric evolution, while it shows stronger absorption features of intermediate-mass elements (especially Ca ii) in the early-time spectra. Based on simple modeling of the observed light curves, we derived the mass of synthesized 56Ni as MNi = 0.075 0.025 M , and the mass and total energy of the ejecta as Mej = 1.00 0.20M and Eej = 1.45 0.25 foe, respectively. Given these typical explosion parameters, the early detection, and the extensive observations, we suggest that SN 2014L could be a template sample for the investigation of SNe Ic.
Rhizosphere sediments and plant samples were collected at five sites in a muddy tidal flat of Yangtze Estuary. The enzymatic activities and heavy metal concentrations in the sediment–plant system of ...the muddy tidal flat were analyzed. The results indicated that in muddy tidal plants, Cr and Zn were accumulated in roots and more Mn was transported upwards and accumulated in the plant tissues above the ground. The urease activities, content of Active Mn, Active Zn and Active Cu, and the concentration of Zn in the whole plant–sediment system were influenced by OM and EC in the rhizosphere sediment. Enzymatic activities were sensitive to the heavy metals in sediment–plant system of the muddy tidal flat. Urease activities were inhibited by Active Mn and Active Zn. Catalase activities were greatly activated by Active Cr and Active Mn. Acid phosphatase activities could be activated by Active Cr. Alk-pho had positive correlations with Cr in the plant body (R = 0.795, p < 0.01). The activities of urease could be used as an index for the evaluation of Active Mn and Active Zn in the rhizosphere sediment. The activities of alkaline phosphatase could be an effective indicator for the phyto-availability of Cr in sediment–plant system of Yangtze Estuary.
Whole genome amplification (WGA) is a technology for non‐selective amplification of the whole genome sequence, first appearing in 1992. Its primary purpose is to amplify and reflect the whole genome ...of trace tissues and single cells without sequence bias and to provide sufficient DNA template for subsequent multigene and multilocus analysis, along with comprehensive genome research. WGA provides a method to obtain a large amount of genetic information from a small amount of DNA and provides a valuable tool for preserving limited samples in molecular biology. WGA technology is especially suitable for forensic identification and genetic disease research, along with new technologies such as next‐generation sequencing (NGS). In addition, WGA is also widely used in single‐cell sequencing. Due to the small amount of DNA in a single cell, it is often unable to meet the amount of samples needed for sequencing, so WGA is generally used to achieve the amplification of trace samples. This paper reviews WGA methods based on different principles, summarizes both amplification principle and amplification quality, and discusses the application prospects and challenges of WGA technology in molecular diagnosis and medicine.
Whole genome amplification (WGA) is a technology for non‐selective amplification of the whole genome sequence. This paper reviews WGA methods based on different principles, summarizes both amplification principle and amplification quality, and discusses the application prospects and challenges of WGA technology in molecular diagnosis and medicine.
Insects that can perform flapping-wing flight, climb on a wall, and switch smoothly between the 2 locomotion regimes provide us with excellent biomimetic models. However, very few biomimetic robots ...can perform complex locomotion tasks that combine the 2 abilities of climbing and flying. Here, we describe an aerial-wall amphibious robot that is self-contained for flying and climbing, and that can seamlessly move between the air and wall. It adopts a flapping/rotor hybrid power layout, which realizes not only efficient and controllable flight in the air but also attachment to, and climbing on, the vertical wall through a synergistic combination of the aerodynamic negative pressure adsorption of the rotor power and a climbing mechanism with bionic adhesion performance. On the basis of the attachment mechanism of insect foot pads, the prepared biomimetic adhesive materials of the robot can be applied to various types of wall surfaces to achieve stable climbing. The longitudinal axis layout design of the rotor dynamics and control strategy realize a unique cross-domain movement during the flying-climbing transition, which has important implications in understanding the takeoff and landing of insects. Moreover, it enables the robot to cross the air-wall boundary in 0.4 s (landing), and cross the wall-air boundary in 0.7 s (taking off). The aerial-wall amphibious robot expands the working space of traditional flying and climbing robots, which can pave the way for future robots that can perform autonomous visual monitoring, human search and rescue, and tracking tasks in complex air-wall environments.
The maximum load of wing and fuselage increases sharply while flapping-wing micro air vehicles(FWMAVS) flutters at high frequencies, which seriously affect the flight performance and flight life. The ...mathematical models of wing lift, drag and inertial forces during the FWMAVs fluttering are established, based on the analysis of movement and force conditions of the wing. A multi-objective optimization model targeting at improving the distribution of loads in the time domain is then proposed and solved by using NSGA-Ⅱ algorithm in Matlab environment. After all the work, the Pareto optimal solution set of the hovering state is obtained. Comparison and analysis of the data show that after the optimization, the peaks of lift and inertial forces decline significantly and the load distribution is obviously improved.
The model of Nano quad-rotors contains many uncertainties such as an external disturbance from a wind field, highly non-linear strong coupling between variables and body measurement errors. To deal ...with these uncertainties and control the Nano quad-rotors, a novel data-based disturbance observer (DO) is firstly proposed to observe disturbances from a wind field and perturbations from errors of parameter estimation. Then the DO is used to improve the conventional dynamic inversion (DI) method to obtain an enhanced dynamic inversion (EDI) method, which relies only on roughly estimated geometrical parameters, thus eliminating the largest flaw of conventional DI, namely depending on detailed plant information. Simulation results show that the method proposed achieved good trajectory tracking with only roughly estimated geometrical values under wind field; the DO proposed can accurately estimate disturbance from a wind field and perturbation from error of parameter estimation.
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