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Tetranychus urticae Koch is a worldwide agricultural pest mite that feeds on more than 1100 kinds of crops. The mite has developed a high level of tolerance to high temperatures, but the physiological mechanism underlying the outstanding adaptability of this pest to high temperatures remains unclear. To clarify the physiological mechanisms of T. urticae in response to short-term heat stress, four temperatures (36, 39, 42, and 45 °C) and three short-term heat durations (2, 4, and 6 h) were conducted to test the effects on protein content, the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), and the total antioxidant capacity (T-AOC). The results showed that protein content, antioxidant enzyme activity, and T-AOC in T. urticae were significantly induced by heat stress. These results suggest that heat stress induces oxidative stress and that antioxidant enzymes play an important role in reducing oxidative damage in T. urticae. The data of this study will provide a basis for further research on the molecular mechanisms of thermostability and ecological adaptability of T. urticae.

Tetranychus urticae Koch is a worldwide pest mite which can cause continuous damage to multiple plants even in hot environment such as greenhouse due to its strong endurance to high temperature. In order to clarify the physiological mechanisms of T. urticae in response to short-term heat stress, four high temperatures (36, 39, 42, and 45°C), three short-term heat durations (2, 4, and 6 h) were conducted to test the effects on the protein content of T. urticae and the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and total antioxidant capacity (T-AOC), respectively. The results showed that protein content, antioxidant enzymes activity, and T-AOC in T. urticae were significantly affected by both the high temperature and duration after treatment, meanwhile, they showed same trends of increased at 25–39℃, then decreased at 39–42℃ except for CAT activity. The highest values of SOD activity, POD activity and T-AOC were all obtained at 39℃-4h, and that of CAT activity was obtained at 39℃-2h. The higher levels of T-AOC serve an important signal demonstrating that T. urticae has other antioxidant mechanisms except for antioxidant enzymes. Those results suggested that heat stress induces oxidative stress, and antioxidant enzymes played important role in reducing oxidative damage in T. urticae. which provided a basis for further research on the molecular mechanisms of thermostability and ecological adaptability of T. urticae.

This paper focuses on the dynamic tracking control of ammunition manipulator system. A standard state space model for the ammunition manipulator electro-hydraulic system (AMEHS) with inherent nonlinearities and uncertainties considered was established. To simultaneously suppress the violation of tracking error constraints and the complexity of differential explosion, a barrier Lyapunov functions-based dynamic surface control (BLF-DSC) method was proposed for the position tracking control of the ammunition manipulator. Theoretical analysis prove the stability of the closed-loop overall system and the tracking error converges to a prescribed neighborhood asymptotically. The effectiveness and dynamic tracking performance of the proposed control strategy is validated via simulation and experimental results.

The strong adhesion of thermally conductive silicone encapsulants on highly integrated electronic devices can avoid external damages and lead to an improved long-term reliability, which is critical for their commercial application. However, due to their low surface energy and chemical reactivity, the self-adhesive ability of silicone encapsulants to substrates need to be explored further. Here, we developed epoxy and alkoxy groups-bifunctionalized tetramethylcyclotetrasiloxane (D4H-MSEP) and boron-modified polydimethylsiloxane (PDMS-B), which were synthesized and utilized as synergistic adhesion promoters to provide two-component addition-cured liquid silicone rubber (LSR) with a good self-adhesion ability for applications in electronic packaging at moderate temperatures. The chemical structures of D4H-MSEP and PDMS-B were characterized by Fourier transform infrared spectroscopy. The mass percentage of PDMS-B to D4H-MSEP, the adhesion promoters content and the curing temperature on the adhesion strength of LSR towards substrates were systematically investigated. In detail, the LSR with 2.0 wt% D4H-MSEP and 0.6 wt% PDMS-B exhibited a lap-shear strength of 1.12 MPa towards Al plates when curing at 80 °C, and the cohesive failure was also observed. The LSR presented a thermal conductivity of 1.59 W m−1 K−1 and good fluidity, which provided a sufficient heat dissipation ability and fluidity for potting applications with 85.7 wt% loading of spherical α-Al2O3. Importantly, 85 °C and 85% relative humidity durability testing demonstrated LSR with a good encapsulation capacity in long-term processes. This strategy endows LSR with a good self-adhesive ability at moderate temperatures, making it a promising material requiring long-term reliability in the encapsulation of temperature-sensitive electronic devices.

Firms compete intensely in sponsored search. Their bidding strategies hinge on understanding who competes with whom, how they compete, and how consumers react to competing advertisements. In this context, we investigate how firm competition impacts consumers’ click-through behaviors in search advertising from a strategic group perspective. Using search results from Google and consumers’ clickstream data, we found strong negative externality for competitors within the same strategic group relative to competitors across strategic groups: firms reap fewer click-throughs when an advertisement of another firm from the same strategic group is also displayed in search results, relative to when other displayed advertisers are not from the same group. This indicates that when competitors from the same strategic group are likely to appear in the results of a sponsored search auction, the focal firm would be better off avoiding head-to-head competition in the auction. However, we did not find empirical evidence of such firm behaviors, suggesting myopia or the inability of firms to avoid such competition. We also show that when multiple firms from the same strategic group appear in search results, the closer the focal firm is located to such competing firms, the more click-throughs the firm accrues. This suggests that firms should stay close to their within-group competitors when they compete in the same search auction. Further, our empirical results indicate that firms are indeed doing so. Using another set of data from Google AdWords reports, we show that our findings are also robust to multi-keyword bidding scenarios. These findings represent the first attempt to understand the impact of strategic groups in search advertising and provide interesting implications for advertisers and search engines.

A polydimethylsiloxane armed with epoxy, alkoxy and acrylate groups was synthesized from silanol terminated-PDMS and epoxy and acrylate groups functionalized silane coupling agents, and utilized as the adhesion promoter (AP) to prepare addition-cured liquid silicone rubber that exhibited self-adhesion ability (SA-LSR) with biocompatible thermoplastic polyurethanes (TPU) sheets. The structural characteristics of AP were characterized by Fourier transform infrared (FTIR) spectroscopy, which demonstrated the strong adhesion to polyester-based TPU sheets due to a sufficient amount of acrylate groups, epoxy groups and silanol groups obtained by the hydrolysis of alkoxy groups. In detail, the peel-off strength of SA-LSR and TPU joints reached up to 7.63 N mm−1 after the optimization of adhesion promoter including type and content, and curing condition including time and temperature. The cohesive failure was achieved during the sample breakage process. Moreover, the SA-LSR showed a good storage stability under proper storage conditions. This design strategy provided the feasibility to combine the advantages of addition-cured liquid silicone rubber and plastics with low melting points, promoting the potential application range of those silicone-based materials.

To the Editor Opioid therapy is the first-line pharmacological approach for moderate-to-severe pain after surgery, but the potential overprescribing of opioids after surgery may contribute to opioid-related adverse events.[1][1] Given the lack of clinical evidence regarding the consumption patterns

An asynchronous microgrid (ASMG) with silicon carbide (SiC) MOSFET-based power conditioning system (PCS) is an attractive option for future microgrids, which can potentially improve microgrid dynamic performance and grid power quality. To support future microgrids’ needs for higher power, scaling PCS power via paralleling multiple modules or converters is a potential solution. In this paper, a strategy for scalable ASMG PCS operation is proposed. MMC-based PCSs are implemented to demonstrate the proposed strategy, including MMC paralleling operation analysis and corresponding control functions. Experimental results are provided to demonstrate the scalable PCS operation at 25 kV rated voltage.

Medium voltage (MV) asynchronous microgrids have numerous unique benefits over regular synchronous MV ac microgrids. This paper focuses on a MV transformer less asynchronous microgrids power conditioning system (PCS) using 10 kV SiC MOSFETs. The benefits of a 10 kV SiC MOSFET based PCS include simplified topology, higher control bandwidth, and hence more advanced control functions, although it is still challenging to apply 10 kV SiC MOSFETs with their associated much faster switching speed in MV systems. A modular design approach is adopted in the design and implementation of the PCS as well as its controller. The sophisticated grid functions of the asynchronous microgrid PCS are supported by a hierarchical modular control system. A 100 kVA back-to-back transformer less PCS for a 13.8 kV MV grid is developed and tested at rated voltage and power.

Asynchronous microgrid (ASMG) is a microgrid concept where the ac microgrid is connected to a utility grid through a power conditioning system (PCS). The development of high voltage (HV, >3.3 kV) silicon carbide (SiC) MOSFET technology promotes the implementation of ASMG PCS converters. However, the system-level benefits from SiC MOSFETs have not been well studied for this application. This paper discusses ASMG system stability enhancement resulting from HV SiC MOSFET-based PCS converters. HV SiC MOSFET-based PCS converters can achieve high control frequency, which can benefit the potential harmonic instability caused by the digital control delay. A detailed theoretical analysis is provided, and experimental results for the stability enhancement capability are demonstrated on a converter-based hardware testbed (HTB).

This paper provides an analysis of the desat protection for high voltage (>3.3 kV) SiC MOSFETs from the perspective of noise immunity. The high positive dv/dt with long voltage rise time generated by high voltage SiC MOSFETs is identified as a major threat to noise immunity of the desat protection circuitry. The impact of numerous influencing factors is analyzed, such as parasitic inductance, damping resistance, and clamping impedance. In some cases, small parasitic capacitances (

A supra-amphiphilic polymer (SAP) with controlled molecular structures is constructed, in this work, via self-complementary hydrogen bonding of guanosine groups between a hydrophilic block, poly(N-isopropylacrylamide), and a hydrophobic block, poly(ε-caprolactone). By simply changing the mixing ratio of the guanosine-capped hydrophilic and hydrophobic blocks, a series of SAPs with tailored nanostructures are constructed, which can further self-assemble into different nano-aggregates in solution, including spheres, vesicles and large vesicle micelles. The thermo-induced phase transition of the hydrophilic block induces the fusion and aggregation of the nanoparticles into irregular particles upon heating, which further transform to large compound vesicles after cooling.

A novel block copolymer is fabricated by orthogonally coupling two end-functionalized polymers, glucose-capped methoxypoly(ethylene glycol) (mPEG2k-diol) and phenylboronic acid-capped poly(e-caprolactone) (PBA-PCL), with dual boronate ester and B N/B O dynamic covalent interactions. Due to their synergetic effect, this block copolymer can self-assemble into micelles in aqueous solution with high stability. More importantly, micellar disassembly can be only triggered in the presence of both signal inputs, acid and salt, displaying an “AND” logic-gate responsive behavior.

To investigate whether dendritic superstructures can be formed from random copolymers, the morphological evolution of a random copolymer, poly(p-dioxanone-co-butylene-co-succinate) (PPBS), is tracked at different crystallization temperatures by optical microscopy. The crystal morphology is regulated by controlling the molecular structure of PPBS as well as the crystallization temperatures, that is, from rounded spherulite for the homopolymer counterpart to dendrites for the copolymer with high p-dioxanone (PDO) content and crystallization temperature. Different from previous works on dendritic crystals, interestingly, film thickness shows no obvious effect on the formation of dendrites. While we find that the crystal growth rate is seriously frustrated by the random structures of PPBS copolyester. Besides, small-angle X-ray scattering (SAXS) analysis indicated that the inter-lamellar region of PPBS copolyester is highly affected by the crystallization temperature. The PDO content, random structure, and high crystallization temperature were believed to be the main factors for the crystals transition from well-rounded spherulite to dendritic crystals.

HCHO removal from indoor air was usually slow and inefficient due to the low concentration but persistent release, inadequate oxidation and less efficient catalysts at room temperature. PEC (photo-electro-catalysis) can better remove pollutant than PC (photocatalysis) or EC (electro-catalysis), but was rarely used directly in indoor air purification, because often aqueous electrolyte was not considered in indoor air purification reactor. Theoretically, removing HCHO in indoor air by PEC is possible, the question is how to integrate gas phase reaction with electric field and electrolyte. In this article, using copper anode in a thin film liquid electrolyte and high activity Pt/TiO2-ZnO cathode, efficient HCHO removal was realized by photo-electro-catalytic oxidation. The nano catalyst was prepared by sol-gel method and loaded on stainless steel mesh as cathode. Its structure, morphology and photocatalytic properties were characterized. The effect of Pt loading and/or external resistances on the removal efficiencies were investigated. Within 120 min of reaction time, 74% HCHO (0.16 mg/m3, in 5.56 10−3 m3 air volume) was removed using 36 cm2 cathode loaded with 4.16 10−3 mg/cm2 catalyst, while only 42% and 53% was removed respectively in PC and EC using the same catalyst and reactor.