In this paper, on–off switching digitization of a W-band variable gain power amplifier (VGPA) with above 60 dB dynamic range is introduced for large-scale phased array. Digitization techniques of on–off switching modified stacking transistors with partition are proposed to optimize configuration of control sub-cells. By the proposed techniques, gain control of a radio frequency variable gain amplifier (VGA) could be highly customized for both coarse and fine switching requirements instead of using additional digital-to-analog converters to tune the overall amplifier bias. The designed VGA in 130 nm SiGe has achieved switchable gain range from −46.4 to 20.6 dB and power range from −25.0 to 15.7 dBm at W band. The chip size of the fabricated VGPA is about 0.31 mm × 0.1 mm.

This paper proposes an online robust self-learning terminal sliding mode control (RS-TSMC) with stability guarantee for balancing control of reaction wheel bicycle robots (RWBR) under model uncertainties and disturbances, which improves the balancing control performance of RWBR by optimising the constrained output of TSMC. The TSMC is designed for a second-order mathematical model of RWBR. Then robust adaptive dynamic programming based on an actor-critic algorithm is used to optimise the TSMC only by data sampled online. The system closed-loop stability and convergence of the neural network weights are guaranteed based on the Lyapunov analysis. The effectiveness of the proposed algorithm is demonstrated through simulations and experiments.

The discovery that blazars dominate the extra-galactic $\gamma$-ray sky is a triumph in the Fermi era. However, the exact location of $\gamma$-ray emission region still remains in debate. Low-synchrotron-peaked blazars (LSPs) are estimated to produce high-energy radiation through the external Compton process, thus their emission regions are closely related to the external photon fields. We employed the seed factor approach proposed by Georganopoulos et al. It directly matches the observed seed factor of each LSP with the characteristic seed factors of external photon fields to locate the $\gamma$-ray emission region. A sample of 1 138 LSPs with peak frequencies and peak luminosities was adopted to plot a histogram distribution of observed seed factors. We also collected some spectral energy distributions (SEDs) of historical flare states to investigate the variation of $\gamma$-ray emission region. Those SEDs were fitted by both quadratic and cubic functions using the Markov-chain Monte Carlo method. Furthermore, we derived some physical parameters of blazars and compared them with the constraint of internal $\gamma\gamma$-absorption. We find that dusty torus dominates the soft photon fields of LSPs and most $\gamma$-ray emission regions of LSPs are located at 1–10 pc. The soft photon fields could also transition from dusty torus to broad line region and cosmic microwave background in different flare states. Our results suggest that the cubic function is better than the quadratic function to fit the SEDs.

Understanding settling motion of coral grains is important in terms of protection of coral reef systems and resotoration of the associated ecosystems. In this paper, a series of laboratory experiments was conducted to investigate the settling motion, using optical microscopy to measure shape parameters of coral grains and the particle-filtering-based object tracking to reconstruct the three-dimensional trajectory. Three characteristic descent regimes, namely, tumbling, chaotic and fluttering, are classified based on the three-dimensional trajectory, the spiral radius variation and the velocity spectrum. It is demonstrated that if one randomly picks up one coral grain, then the probabilities of occurrence of the three regimes are approximately $26\,\%$, $42\,\%$ and $32\,\%$, respectively. We have shown that first, the dimensionless settling velocity generally increases with the non-dimensional diameter and Corey shape factor and second, the drag coefficient generally decreases with the Reynolds number and Corey shape factor. Based on this, the applicability of existing models on predicting settling velocity and drag coefficient for coral grains is demonstrated further. Finally, we have proposed extended models for predicting the settling velocity. This study contributes to better understanding of settling motion and improves our predictive capacity of settling velocity for coral grains with complex geometry.

We report a compact, tunable, self-starting, all-fiber laser-based asynchronous optical sampling (ASOPS) system. Two Er-doped fiber oscillators were used as the pulsed-laser source, whose repetition rate could be set at 100 MHz with a tuning range of 1.25 MHz through a fiber delay line. By employing phase-locked and temperature control loops, the repetition rate offset of the two lasers was stabilized with 7.13 × 10−11 fractional instability at an average time of 1 s. Its capabilities in the terahertz regime were demonstrated by terahertz time-domain spectroscopy, achieving a spectral bandwidth of 3 THz with a dynamic range of 30 dB. The large range of repetition rate adjustment in our ASOPS system has the potential to be a powerful tool in the terahertz regime.

We report on the generation of a mid-infrared (mid-IR) frequency comb with a maximum average output power of 250 mW and tunability in the 2.7–4.0 μm region. The approach is based on a single-stage difference frequency generation (DFG) starting from a compact Yb-doped fiber laser system. The repetition rate of the near-infrared (NIR) comb is locked at 75 MHz. The phase noise of the repetition rate in the offset-free mid-IR comb system is measured and analyzed. Except for the intrinsic of NIR comb, environmental noise at low frequency and quantum noise at high frequency from the amplifier chain and nonlinear spectral broadening are the main noise sources of broadening the linewidth of comb teeth, which limits the precision of mid-IR dual-comb spectroscopy.

This paper reviews previous studies on metamaterials and its application to wireless power transfer (WPT) technologies, as well as discussing about development opportunities and technical challenges for the contactless charging of electric vehicles (EVs). The EV establishes a bridge between sustainable energies and our daily transportation, especially the park-and-charge and move-and-charge for EVs have attracted increasing attentions from the academia and the industry. However, the metamaterials-based WPT has been nearly unexplored specifically for EVs by now. Accordingly, this paper gives an overview for the metamaterial-based WPT technologies, with emphasizes on enhancing efficiency, increasing distance, improving misalignment tolerance, and compacting size. From the perspective of EV wireless charging, this paper discusses about the breakthrough to current WPT technique bottlenecks and prospective EV charging scenarios by utilizing the left-handed material. Meanwhile, the technical issues to be addressed are also summarized in this paper, which aims to arouse emerging research topics for the future development of EV wireless charging systems.

Although the brittle material in analogue models is characterized by a linear Navier-Coulomb behaviour and rate-independent deformation, the geometry and style of deformation in accretionary wedges is sensitive to shortening velocity. In this study we have constructed a series of analogue models with various shortening velocities in order to study the influence of shortening velocity on the geometry and kinematics of accretionary wedges. Model results illustrate how shortening velocity has an important influence on the geometry and kinematics of the resulting wedge. In general, for models having similar bulk shortening, the accretionary wedges with higher velocities of shortening are roughly steeper, higher and longer, as well as having larger critical wedge angles and height. It accommodates a number of foreland-vergent thrusts, larger fault spacing and displacement rates than those of low- to medium-velocity shortening, which indicates a weak velocity-dependence in geometry of the wedge. Moreover, models with a high velocity of shortening undergo larger amounts of volumetric strain and total layer-parallel shortening than models with low- to medium-velocity shortening. The former accommodate a greater development of back thrusts and asymmetric structures; a backwards-to-forwards style of wedge growth therefore occurs in the frontal zone under high-velocity shortening.

SG-III laser facility is now the largest laser driver for inertial confinement fusion research in China. The whole laser facility can deliver 180 kJ energy and 60 TW power ultraviolet laser onto target, with power balance better than 10%. We review the laser system and introduce the SG-III laser performance here.

Most species of the genus Eulecanium Cockerell (Hemiptera: Coccidae) are important economic pests for ornamental plants and fruit trees. Two morphologically similar species, Eulecanium giganteum Shinji and E. kuwanai Kanda, are distributed mainly in China and are quite difficult to identify because of the paucity of distinguishing characteristics, which can only be observed in slide-mounted young, adult females. Furthermore, we demonstrate here that the species occur in sympatry and on many of the same host plants. Mitochondrial cytochrome c oxidase I (COI) and the D2–D3 expansion segments of 28S rDNA were used for accurate identification of these two Eulecanium species from 19 different locations in China. The average K2P distances of COI sequences were 0.47% in E. kuwanai and 0.32% in E. giganteum, and the interspecific divergences varied from 7.23% to 8.34%. Neighbour-joining (NJ) trees of COI and 28S rDNA revealed two distinct non-overlapping clusters, respectively. Meanwhile, “best close match” analysis also showed that 100% of individuals were classified successfully using COI and 28 S sequences. Differentiating between E. giganteum and E. kuwanai is challenging when using ecological and morphological traits. In contrast, identification using DNA diagnostics appears to be very effective, especially when slide-mounted specimens are difficult to obtain.

A magnetoelectric theoretical model combing piezoelectric and piezomagnetic parts about the longitudinal vibration was proposed for the laminate composite based on equivalent circuit. The model shows that the magnetoelectric voltage is relative to the thickness ratio, total thickness, frequency and loss. A simple laminate magnetoelectric composite was prepared by bonding a nickel plate and a multilayer piezoelectric vibrator together for the experimental research. The multilayer vibrator enjoys high capacitance, large effective area and low thickness, leading to a high magnetic field sensitivity of 1 mOe at the magnetoelectric field coefficient of 2.58 V/cmOe in the simple composite with nickel thickness of 0.2 mm. The model fits the resonance frequency well with the experimental results. Numerical calculation well predicates the magnetoelectric experimental behaviors, presenting a magnetoelectric maximum at about the thickness ratio 0.3 between the nickel plate and multilayer vibrators. This approach provides a method for the magnetoelectric application.

Hsp90 is a widely distributed and highly conserved molecular chaperone that is ubiquitously expressed throughout nature, being one of the most abundant proteins within non-stressed cells. This chaperone is up-regulated following stressful events and has been involved in many cellular processes. In Toxoplasma gondii, Hsp90 could be linked with many essential processes of the parasite such as host cell invasion, replication and tachyzoite-bradyzoite interconversion. A Protein-Protein Interaction (PPI) network approach of TgHsp90 has allowed inferring how these processes may be altered. In addition, data mining of T. gondii phosphoproteome and acetylome has allowed the generation of the phosphorylation and acetylation map of TgHsp90. This review focuses on the potential roles of TgHsp90 in parasite biology and the analysis of experimental data in comparison with its counterparts in yeast and humans.

A 9-week feeding trial was conducted to evaluate the effects of dietary cholesterol supplementation at different levels (0, 0·3, 0·6, 0·9, 1·2 and 1·5 %) on growth and cholesterol metabolism of rainbow trout (Oncorhynchus mykiss) fed soyabean meal (SBM)-based diets. Daily growth coefficient (DGC) steadily increased when the supplemental cholesterol was increased by up to 1·2 %, but declined upon further addition. The total cholesterol (TC), HDL-cholesterol (HDL-C) and LDL-cholesterol (LDL-C) levels in plasma generally increased when the supplemental cholesterol was increased by up to 1·2 %. Thereafter, the TC level reached a plateau, the LDL-C level showed a marked decline, whereas the HDL-C level continued to increase. Dietary cholesterol supplementation generally increased the total lipid and cholesterol levels in liver; the total lipid and TAG levels in muscle; the TC, free cholesterol, cholesteryl ester and total bile acid levels in intestinal contents; and the triiodothyronine and Ca levels in plasma. However, significant differences were mainly observed with high levels of supplemental cholesterol (0·9–1·5 %). Low levels of supplemental cholesterol (0·3–0·9 %) decreased hepatic 3-hydroxy-3-methyl-glutaryl-CoA reductase and cholesterol 7α-hydroxylase activities, but high levels of supplemental cholesterol (1·5 %) increased hepatic acyl-CoA:cholesterol acyl transferase and cholesterol 7α-hydroxylase activities. These results suggest that rainbow trout fed SBM-based diets have a certain ‘cholesterol-buffering capacity’, which in turn suggests the possibility of the inhibition of exogenous cholesterol absorption and/or inadequate endogenous production of cholesterol in trout fed SBM-based diets. DGC increased steadily with increasing supplemental cholesterol level up to 1·2 %, and the growth-promoting effects might be related to the alleviation of the negative effects caused by a soyabean diet and/or make up for the deficiency of endogenous cholesterol in rainbow trout.

A simple and environmentally benign three-step hydrothermal method was developed for growing oriented single-crystalline TiO2-B and/or anatase TiO2 nanowire arrays on titanium foil over large areas. These nanowire arrays are suitable for use as the anode in lithium ion batteries; they exhibit specific capacities ranging from 200–250 mAh/g at charge-discharge rates of 0.3 C where 1 C is based on the theoretical capacity of 168 mAh/g. Batteries retain this capacity over as many as 200 charge-discharge cycles. Even at high charge-discharge rates of 0.9 C and 1.8 C, the specific capacities were 150 mAh/g and 120 mAh/g, respectively. These promising properties are attributed to both the nanometer size of the nanowires and their oriented alignment. The comparable electrochemical performance to existing technology, improved safety, and the ability to roll titanium foils into compact three-dimensional structures without additional substrates, binders, or additives suggest that these TiO2 nanowires on titanium foil are promising anode materials for large-scale energy storage.