During the transport., assembly., installation., and operation of a gas-insulated switchgear (GIS), the introduction of metal particles into the unit is inevitable. The presence of metal particles on ...the insulator surface is regarded as a critical factor in insulation failures. Thus, a thorough understanding of the characteristics of metal particles on the insulator surface is critical. In this study, a 126-kV GIS experiment platform with a highly sensitive partial discharge (PD) detection system is established. The movement and PD characteristics of micron-sized metal particles on the insulator surface in a 126-kV GIS under long-time alternating current (AC) stress are investigated. The results demonstrate that the PDs triggered by the micron-sized metal particles are weak and sporadic: the apparent charge of most PDs is lower than 1 pC, and the discharge repetition rate can be as low as once per minute. When two metal particles are sufficiently close to each other, they are charged by the PDs between them. This causes the metal particles to move away from each other and tend to be evenly distributed over the entire insulator surface. Some metal particles can move to stay at the triple junction near the grounded enclosure and center conductor or jump to adhere to the surface of center conductor. This study is anticipated to be a beneficial reference for further understanding the movement and PD characteristics of micron-sized metal particles on the GIS insulator surface.
Pyrazolecarboxamide fungicides are one of the most important classes of agricultural fungicides, which belong to succinodehydrogenase inhibitors (SDHIS). To discover new pyrazolecarboxamide analogues ...with broad spectrum and high activity, a class of new compounds of pyrazole carboxamide derivatives containing thiazole or oxazole ring were designed by scaffold hopping and bioisosterism, and 36 pyrazole carboxamide derivatives with antifungal activity were synthesized. Those compounds were evaluated against five phytopathogenic fungi, Gibberella zeae, Phytophythora capsici, Sclerotonia sclerotiorum, Erysiphe graminis and Puccinia sorghi. The results indicated that most of the compounds displayed good fungicidal activities, especially against E. graminis. Theoretical calculations were carried out at the B3LYP/6-31G (d, p) level and the full geometry optimization was carried out using the 6-31G (d, p) basis set, and the frontier orbital energy, atomic net charges, molecular docking were discussed, and the structure-activity relationships were also studied.
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•The introduction of thiazole or oxazole ring makes our target compounds have good antifungal activities.•The change of three-dimensional structure is necessary for the transformation from insecticidal activity to antifungal activity.•DFT study and molecular docking verify the interaction between small molecule and protein.
•Groove superhydrophobic structure can inhibit frost propagation and ice covering.•Airflow provides sufficient vapor to promote multi-directional frost propagation.•Passive anti-frosting method has ...limited effect under forced convection condition.•Frost propagation time decreases sharply and rises as airflow velocity increases.
The characteristics of frost propagation and distribution on cold plate surfaces under forced convection conditions were studied experimentally. The influence of forced convection on frost propagation was analyzed by comparing it with natural convection. The weakening effect of airflow on the frost suppression of the superhydrophobic and groove-superhydrophobic surfaces was revealed. The results indicate that the superhydrophobic micro-nanostructure increases the required volume of the ice bridge, inhibiting the one-way frost propagation from the sample edge to the center. By evaporating the droplets and forming dry zones in the groove valley, the groove patterns can intercept the generation of the ice bridge, and reduce the frost coverage. Under forced convection, the airflow can continuously provide sufficient water vapor to promote the growth of the droplets and trigger isolated-droplet nucleation, thus accelerating the frost propagation by building ice bridge connections in multiple directions. Moreover, the vapor can deposit in the groove valley to prevent the formation of the dry zone, which causes the anti-frosting function of the groove patterns by regulating the local vapor flux to have a limited effect. With the increase of the airflow velocity, the frost morphology changes from spreading columnar crystals to independent ice blocks covered with a frost layer, and the frost coverage rate increases. The frost propagation time drastically reduces, and then rises slightly due to the change in freezing mode and coalescence of the frozen droplets, which are caused by the intenser convective heat transfer.
Economic geography in China＇s mainland has developed in a different way from that in many other countries. On the one hand, it has been increasingly active in participating in academic dialogues and ...knowledge development led by Anglophone countries; on the other hand, it takes practice-based and policy-oriented research, i.e. satisfying the demands from the Chinese government and society, as the linchpin of research. Since there has been a lot of literature reviewing the development of economic geography in the country before the new millennium, this paper will make a comprehensive analysis of the discipline in 2000–2015, based on a bibliometric survey and research projects done by Chinese economic geographers. The analysis indicates that（1） economic geography research in China＇s mainland is unevenly distributed but concentrated in several leading institutions;（2） traditional research fields like human-nature system, regional disparity, industrial location and transportation geography remain dominant while new topics such as globalization, multinational corporations and foreign direct investments, information and communication technology, producer services, climate change and carbon emission emerge as important research areas;（3） Chinese economic geography is featured by policy-oriented research funded by government agencies, having considerable impacts on regional policy making in China, both national and regional. To conclude, the paper argues that the development of economic geography in China＇s mainland needs to follow a dual track in the future, i.e. producing knowledge for the international academic community and undertaking policy-oriented research to enhance its role as a major consulting body for national, regional and local development.
In this paper, active control for vibration reduction of a flexible marine riser is studied by using boundary control, adaptive control and Lyapunov's synthesis method. To achieve more accurate and ...practical dynamic behavior of the riser, the effects of time-varying internal fluid are considered in dynamics model of the riser. The signum function and adaptive boundary control scheme are design to compensate for the system parametric uncertainties. With the proposed control, the uniform boundedness and closed-looped stability is demonstrated via Lyapunov's direct method. Simulation results illustrate the effectiveness of the proposed control scheme.
The buried-oxide in SOI MOSFET inhibits heat dissipation in the Si film and leads to increase in transistor temperature. This paper reports a simple and accurate characterization method for the ...self-heating effect (SHE) in SOI MOSFETs. The AC output conductance at a chosen bias point is measured at several frequencies to determine the thermal resistance (R/sub th/) and thermal capacitance (C/sub th/) associated with the SOI device. This methodology is important to remove the misleadingly large self-heating effect from the DC I-V data in device modeling. Not correcting for SHE may lead to significant error in circuit simulation. After SHE is accounted for, the frequency-dependent SHE may be disabled in circuit simulation without sacrificing the accuracy, thus providing faster circuit simulation for high-frequency circuits.
Innovation-driven development worldwide is driving scientific and technological (Sci-Tech) progress. As an important form of Sci-Tech achievements, patents provide effective protection and ...transformation opportunities for Sci-Tech innovations; this includes using and exchanging of patents to realize their value. However, realizing patent value involves some challenges: (1) discovering the transformation opportunities and (2) determining the conditions needed to realize patent transformation. To solve these challenges, we introduce a heterogeneous network-based transformation prediction model to discover transformation opportunities and explain the transformation conditions. The model includes: (1) construction of a heterogeneous network, (2) a heterogeneous network-based transformation opportunity prediction method, and (3) a heterogeneous network-based transformation conditions explainable method. The results obtained show that the proposed model can discover transformation opportunities with high evaluation measurements and explainable transformation conditions.
•The heterogeneous network based transformation opportunity prediction method discovers the transformation opportunities.•The heterogeneous network based transformation condition explainable method explains what transformation conditions are needed to realize the transformation.
This article presents new full-wave analytical formulas for the partial element involving the free-space Green's function in the modeling of thin-wire structures for lightning transient analysis. In ...the framework of the partial element equivalent circuit (PEEC) formulation for thin conductors, the partial elements are computed by double-folded line integrals. In layered media, the interaction integrals involve the dyadic Green's function, which contains the free-space Green's function term. The direct numerical computation of these integrals is time-consuming, which hinders the practical application of the full-wave method. Therefore, quasi-static (QS) analytical formulas for orthogonal meshes are widely used, which significantly reduces the computational overhead. However, these existing analytical formulas are derived under the QS hypothesis, which is not suitable for full-wave wideband analysis. The accurate analytical calculation of these partial elements has not been investigated in a comprehensive way so far. Accordingly, this article presents new full-wave analytical formulas for the evaluation of the partial elements for a thin-wire structure. These formulas are derived based on the Taylor series expansion of the full-wave free-space Green's function. The range of applicability of the proposed formulas is analyzed in terms of frequency, length of the conductor, and distance between these conductors. Numerical results computed by the PEEC method are presented, showing that the proposed formulas outperform the conventional QS ones at high frequencies, which makes them more appropriate for wideband modeling.
The extensive use of antibiotics in aquaculture has resulted in the prevalence of antibiotic-resistant bacteria and, consequently, new antibacterial strategies or drugs with clear modes of action are ...urgently needed. Antimicrobial peptides (AMPs) are currently widely considered as alternatives to antibiotics in the treatment of infections in aquatic animals. In this study, we aimed to evaluate the effects of NKL-24, a truncated peptide derived from zebrafish NK-lysin, against Yesso scallop (Patinopecten yessoensis) pathogen, Vibrio parahaemolyticus. The results showed that NKL-24 had a potent antibacterial effect against V. parahaemolyticus via a membrane active cell-killing mechanism. The in vitro study showed that sub-lethal levels of NKL-24 obviously reduced bacterial swimming ability and downregulated the transcription of the selected genes associated with V. parahaemolyticus virulence. Studies on NKL-24 biosafety in hemocytes and in Yesso scallop have shown no adverse effects from this peptide. Bacteria challenge test results demonstrated that NKL-24 significantly decreased the mortality and inhibited bacterial growth in the scallop infected with V. parahaemolyticus, while further in vivo examination revealed that NKL-24 could enhance non-specific immune parameters. Moreover, NKL-24 was capable of modulating a series of V. parahaemolyticus-responsive genes in the scallop. These results suggest the protective action of NKL-24 against V. parahaemolyticus and the potential of this peptide as a promising candidate for aquaculture applications.
•NKL-24 had a potent antibacterial effect against V. parahaemolyticus.•NKL-24 had no cytotoxicity toward Yesso scallop hemocytes.•NKL-24 could enhance the survival of scallops infected with V. parahaemolyticus.•NKL-24 was capable of increasing the bacterial clearance in Yesso scallop.
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