Embedding the intrinsic symmetry of a flow system in training its machine learning algorithms has become a significant trend in the recent surge of their application in fluid mechanics. This paper leverages the geometric symmetry of a four-roll mill (FRM) to enhance its training efficiency. Stabilising and precisely controlling droplet trajectories in an FRM is challenging due to the unstable nature of the extensional flow with a saddle point. Extending the work of Vona & Lauga (Phys. Rev. E, vol. 104(5), 2021, p. 055108), this study applies deep reinforcement learning (DRL) to effectively guide a displaced droplet to the centre of the FRM. Through direct numerical simulations, we explore the applicability of DRL in controlling FRM flow with moderate inertial effects, i.e. Reynolds number $\sim \mathcal{O}(1)$, a nonlinear regime previously unexplored. The FRM’s geometric symmetry allows control policies trained in one of the eight sub-quadrants to be extended to the entire domain, reducing training costs. Our results indicate that the DRL-based control method can successfully guide a displaced droplet to the target centre with robust performance across various starting positions, even from substantially far distances. The work also highlights potential directions for future research, particularly focusing on efficiently addressing the delay effects in flow response caused by inertia. This study presents new advances in controlling droplet trajectories in more nonlinear and complex situations, with potential applications to other nonlinear flows. The geometric symmetry used in this cutting-edge reinforcement learning approach can also be applied to other control methods.

An ultra-wideband current-reused low-noise amplifier (LNA) monolithic microwave integrated circuit design is presented in this letter. Negative feedback networks are employed at both stages of the proposed LNA to expand bandwidth. Furthermore, source adaptive bias networks is designed in the first stage and combined with a current-reused construction to acquire a compact chip size and maintain low power consumption. Then, the validation of design theory is implemented by employing a 0.15-µm gallium arsenide pseudomorphic high-electron-mobility transistor process. The measured results show that the proposed LNA achieves a small signal gain of 15.5–17.8 dB, a noise figure of 3–3.65 dB, and an output 1 dB compression point (OP1 dB) of 14.5–15.5 dBm from the target bandwidth of 2–18 GHz. In addition, the fabricated LNA consumes 220 mW from a 5 V supply and occupies a chip area of 1.2 × 1.5 mm2.

This study is dedicated to achieving efficient active noise control in a supersonic underexpanded planar jet, utilizing control parameters informed by resolvent analysis. The baseline supersonic underexpanded jet exhibits complex wave structures and substantial high-amplitude noise radiations. To perform the active control, unsteady blowing and suction are applied along the nozzle inner wall close to the exit. Employing both standard and acoustic resolvent analyses, a suitable frequency and spanwise wavenumber range for the blowing and suction is identified. Within this range, the control forcing can be significantly amplified in the near field, effectively altering the original sound-producing energetic structure while minimizing far-field amplification to prevent excessive noise. A series of large-eddy simulations are further conducted to validate the control efficiency, demonstrating an over 10 dB reduction in upstream-propagated screech noise. It is identified that the present unsteady control proves more effective than steady control at the same momentum coefficient. The controlled jet flow indicates that the shock structures become more stable, and the stronger the streamwise amplification of the forcing, the more likely it is to modify the mean flow characteristics, which is beneficial for reducing far-field noise radiation. Spectral proper orthogonal decomposition analysis of the controlled flow confirms that the control redistributes energy to higher forcing frequencies and suppresses large-scale antisymmetric and symmetric modes related to screech and its harmonics. The findings of this study highlight the potential of resolvent-guided control techniques in reducing noise in supersonic underexpanded jets and provide a detailed understanding of the inherent mechanisms for effective noise reduction through active control strategies.

Teaching is a highly complex act, and learning to teach in an educational era that combines both teacher-centred and student-centred approaches presents additional challenges. Conducting demonstration lessons (DL) is one of the methods aimed at enhancing teachers’ instructional skills. This study examines the features and functions of this unique type of lesson from the perspective of music demonstration teachers in Guangdong, China. Through observation and interviews, the findings not only reveal the prevalence of DLs as performance-based lessons in Chinese teachers’ professional lives but also explore their distinctions from regular school teaching and their potential for improving teachers’ pedagogical abilities. Concerns and issues related to this type of lesson, along with possible solutions, are also discussed to provide recommendations for incorporating DLs into teacher training programmes in higher education institutions.

A bandwidth expansion strategy for ultra-wideband power amplifiers (PAs) is presented in this letter by adopting a parallel impedance matching architecture. This design strategy can effectively reduce the impedance conversion ratio between the load and the target impedance of the PA, thereby providing a feasible solution for broadband impedance matching. Subsequently, a commercially available 10 W gallium nitride device and a two-stage Wilkinson power divider network are combined to achieve the verification of the proposed theory. The results of the measurement show that within the target frequency band of 0.9–3.9 GHz, 58.5–71.2% of the drain efficiency and 9.1–12 dB of gain can be achieved with a saturated output power of 39.1–42 dBm.

To meet the demands of laser-ion acceleration at a high repetition rate, we have developed a comprehensive diagnostic system for real-time and in situ monitoring of liquid sheet targets (LSTs). The spatially resolved rapid characterizations of an LST’s thickness, flatness, tilt angle and position are fulfilled by different subsystems with high accuracy. With the help of the diagnostic system, we reveal the dependence of thickness distribution on collision parameters and report the 238-nm liquid sheet generated by the collision of two liquid jets. Control methods for the flatness and tilt angle of LSTs have also been provided, which are essential for applications of laser-driven ion acceleration and others.

The prevalence of workaholism has negative consequences on human health. Lack of sleep, a well-known problem among adults in modern society, is often attributed to overwork as a result of workaholism. Yet there is a lack of empirical research examining how and when workaholism will lead to sleep problems. To answer this question and to examine the longitudinal effect of workaholism on sleep in China, we investigate the mediating role of perceived evening responsibilities of work and the moderating effect of work autonomy. Two hundred and five Chinese working adults (58.0% female) voluntarily completed the online questionnaires at Time 1 (T1) and Time 2 (T2; 1-month later). Results showed that workaholism at T1 had a significant and positive correlation with sleep problem at T2. Further analysis suggested that perceived evening responsibilities of work fully mediated the relationship between workaholism and sleep problem. Work autonomy was shown to buffer the positive effect of workaholism on perceived evening responsibilities of work and attenuate the indirect effect of workaholism on sleep problem. While workers should be made aware of the negative impact of workaholism on sleep, organizations should also consider interventions to enhance employees’ autonomy and control of their work.

As the southernmost part of the central segment of the Central Asian Orogenic Belt, the northern Alxa area is characterized by abundant Permian magmatism and records key information on the geological evolution of the Palaeo-Asian Ocean. This study reports new zircon U–Pb and Lu–Hf isotopic and whole-rock geochemical data of the early Permian (285–286 Ma) Huisentala gabbro and Huodonghaer diorites from the Zhusileng–Hangwula Belt in the northern Alxa area. The gabbro is characterized by high Al, Ca, Mg# and light rare-earth elements, and low K, P and high field strength elements (e.g., Ti, Nb and Ta). Furthermore, the gabbro shows heterogeneous zircon ϵHf(t) value (−2.5 to +2.6). The Huodonghaer diorites show high MgO (3.46–6.32 wt%), Mg# (49–58), Sr (408–617 ppm) and Ba (223–419 ppm), and low FeOT/MgO (1.27–1.83) and TiO2 (0.48–0.90 wt%), with geochemical features similar to the high-Mg andesite/diorite. They show radiogenic zircon ϵHf(t) values of +1.2 to +4.9 and high Th/Nb ratios. These features suggest that the Huisentala gabbro and the Huodonghaer diorites were derived from the partial melting of mantle peridotite that was metasomatized by subduction-related fluids and by subducted sediment-derived melts, respectively.

A distributed basic matching network (MN) designed method that can achieve multioctave bandwidth and highly efficient power amplifier (PA) for multiband applications is presented in this letter. The distributed network unit with a left-rotating T-type structure is employed to construct the wideband MN, whose topology and circuit parameters are acquired through optimization. Finally, the impedance realized by the designed MN falls into the target impedance region obtained by using multi-harmonic bilateral pull technique in the desired frequency band. For the proof of the method, a broadband highly efficient PA has been designed, fabricated, and measured using commercialized GaN high electron mobility transistors (HEMT). The measured results show that the implemented PA achieves a bandwidth of 137.8% from 0.7 to 3.8 GHz. The drain efficiency is between 59% and 70% with an output power of greater than 39 dBm and a gain ranging from 9 to 12.1 dB.

Toll-interacting protein (Tollip) participates in multiple biological processes. However, the biological functions of Tollip proteins in insects remain to be further explored. Here, the genomic sequence of tollip gene from Antheraea pernyi (named Ap-Tollip) was identified with a length of 15,060 bp, including eight exons and seven introns. The predicted Ap-Tollip protein contained conserved C2 and CUE domains and was highly homologous to those tollips from invertebrates. Ap-Tollip was highly expressed in fat body compared with other determined tissues. As far as the developmental stages were concerned, the highest expression level was found at the 14th day in eggs or the 3rd day of the 1st instar. Ap-Tollip was also obviously regulated by lipopolysaccharide, polycytidylic acid or 20E in different tissues. In addition, the interaction between Ap-Tollip and ubiquitin was confirmed by western blotting and pull-down assay. RNAi of Ap-Tollip significantly affected the expression levels of apoptosis and autophagy-related genes. These results indicated that Ap-Tollip was involved in immunity and development of A. pernyi.

Lamprophyre dikes and quartz veins in the Sizhuang gold deposit are used to date and unravel the Early Cretaceous stress regime in the Jiaodong Peninsula, North China Craton. The lamprophyre dikes are grouped into two major sets, trending NNW–SSE and NNE–SSW, respectively, and a subsidiary one, trending WNW–ESE, whereas the quartz veins trend mainly NNE–SSW. The age of lamprophyre dikes’ intrusion was robustly calculated at c. 119 Ma by phlogopite 40Ar–39Ar dating. The fuzzy clustering technique defined four stress states, which were grouped into three stress regimes in Sizhuang. Furthermore, these stress regimes were interrelated with two regional far-field stress regimes, ST1 and ST2, defined by the available published fault-slip data near Sizhuang by applying the separation and stress inversion TR method (TRM). The palaeostress reconstruction indicates that extension and strike-slip tectonics (i.e. transtension) affect the emplacement of the lamprophyre dikes and quartz veins. More precisely, the dike emplacement occurred under unstable stress conditions related to the shift from E–W pure extension–transtension to WNW–ESE transtension, whereas the quartz veins formed under relatively stable WNW–ESE transtension with the variant and increasing fluid pressure ( ${P_{\rm{f}}})$ giving rise to the strike-slip against dip-slip kinematics along the faults. The change from the ST1 to ST2 stress regimes reflects the significant clockwise rotation in the palaeo-Pacific plate subduction direction and defines the switching time at c. 119 Ma as precisely obtained by the lamprophyre dating.

We find generalized conformal measures and equilibrium states for random dynamics generated by Ruelle expanding maps, under which the dynamics exhibits exponential decay of correlations. This extends results by Baladi [Correlation spectrum of quenched and annealed equilibrium states for random expanding maps. Comm. Math. Phys. 186 (1997), 671–700] and Carvalho et al [Semigroup actions of expanding maps. J. Stat. Phys. 116(1) (2017), 114–136], where the randomness is driven by an independent and identically distributed process and the phase space is assumed to be compact. We give applications in the context of weighted non-autonomous iterated function systems, free semigroup actions and introduce a boundary of equilibria for not necessarily free semigroup actions.

Previous research indicates that parental emotion socialization (ES) practices play important roles in adolescents’ social and emotional development. However, longitudinal studies testing bidirectional effects are relatively scarce. Additionally, most studies have focused on people from Western societies. In the current 3-year, multi-informant, longitudinal study of Chinese adolescents and their parents, we investigated prospective bidirectional effects between parental positive ES practices and adolescents’ psychosocial adjustment (i.e., self-esteem and depressive symptoms). Adolescents (N = 710 at T1, 50% boys, Mage = 12.41, SD = 0.59) reported on parental positive ES practices and their own depressive symptoms and self-esteem when they were in 7th, 8th, and 9th grade. Mothers and fathers reported on their own use of positive ES practices at all three time points. We utilized a random intercept cross-lagged panel model to examine between- and within-family effects. Overall results showed robust effects of adolescent depressive symptoms on parental positive ES practices and bidirectional effects between parental ES and adolescent self-esteem. Effects differed by informants whether using adolescent-perceived data, or mother- or father-reported data. However, these child effects and bidirectional effects did not differ by adolescent sex. Our findings add to the understanding of parental ES and adolescent psychosocial adjustment.

Trypanosoma musculi is a, globally distributed, mouse-specific haemoflagellate, of the family Trypanosomatidae, which shares similar characteristics in morphology with Trypanosoma lewisi. The kinetoplast (mitochondrial) DNA of Trypanosomatidae flagellates is comprised of catenated maxicircles and minicircles. However, genetic information on the T. musculi kinetoplast remains largely unknown. In this study, the T. musculi maxicircle genome was completely assembled, with PacBio and Illumina sequencing, and the size was confirmed at 34 606 bp. It consisted of 2 distinct parts: the coding region and the divergent regions (DRs, DRI and II). In comparison with other trypanosome maxicircles (Trypanosoma brucei, Trypanosoma cruzi and T. lewisi), the T. musculi maxicircle has a syntenic distribution of genes and shares 73.9, 78.0 and 92.7% sequence identity, respectively, over the whole coding region. Moreover, novel insertions in MURF2 (630 bp) and in ND5 (1278 bp) were found, respectively, which are homologous to minicircles. These findings support an evolutionary scenario similar to the one proposed for insertions in Trypanosoma cruzi, the pathogen of American trypanosomiasis. These novel insertions, together with a deletion (281 bp) in ND4, question the role of Complex I in T. musculi. A detailed analysis of DRII indicated that it contains numerous repeat motifs and palindromes, the latter of which are highly conservative and contain A5C elements. The comprehensively annotated kinetoplast maxicircle of T. musculi reveals a high degree of similarity between this parasite and the maxicircle of T. lewisi and suggests that the DRII could be a valuable marker for distinguishing these evolutionarily related species.

This work addresses the effects of different thermal sidewall boundary conditions on the formation of flow states and heat transport in two- and three-dimensional Rayleigh–Bénard convection (RBC) by means of direct numerical simulations and steady-state analysis for Rayleigh numbers ${\textit {Ra}}$ up to $4\times 10^{10}$ and Prandtl numbers ${\textit {Pr}}=0.1,1$ and $10$. We show that a linear temperature profile imposed at the conductive sidewall leads to a premature collapse of the single-roll state, whereas a sidewall maintained at a constant temperature enhances its stability. The collapse is caused by accelerated growth of the corner rolls with two distinct growth rate regimes determined by diffusion or convection for small or large ${\textit {Ra}}$, respectively. Above the collapse of the single-roll state, we find the emergence of a double-roll state in two-dimensional RBC and a double-toroidal state in three-dimensional cylindrical RBC. These states are most prominent in RBC with conductive sidewalls. The different states are reflected in the global heat transport, so that the different thermal conditions at the sidewall lead to significant differences in the Nusselt number for small to moderate ${\textit {Ra}}$. However, for larger ${\textit {Ra}}$, the heat transport and flow dynamics become increasingly alike for different sidewalls and are almost indistinguishable for ${\textit {Ra}}>10^{9}$. This suggests that the influence of imperfectly insulated sidewalls in RBC experiments is insignificant at very high ${\textit {Ra}}$ – provided that the mean sidewall temperature is controlled.

The southeastern Central Asian Orogenic Belt (CAOB) records the assembly process between several micro-continental blocks and the North China Craton (NCC), with the consumption of the Paleo-Asian Ocean (PAO), but whether the S-wards subduction of the PAO beneath the northern NCC was ongoing during Carboniferous–Permian time is still being debated. A key issue to resolve this controversy is whether the Carboniferous magmatism in the northern NCC was continental arc magmatism. The Alxa Block is the western segment of the northern NCC and contiguous to the southeastern CAOB, and their Carboniferous–Permian magmatism could have occurred in similar tectonic settings. In this contribution, new zircon U–Pb ages, elemental geochemistry and Sr–Nd isotopic analyses are presented for three early Carboniferous granitic plutons in the southwestern Alxa Block. Two newly identified aluminous A-type granites, an alkali-feldspar granite (331.6 ± 1.6 Ma) and a monzogranite (331.8 ± 1.7 Ma), exhibit juvenile and radiogenic Sr–Nd isotopic features, respectively. Although a granodiorite (326.2 ± 6.6 Ma) is characterized by high Sr/Y ratios (97.4–139.9), which is generally treated as an adikitic feature, this sample has highly radiogenic Sr–Nd isotopes and displays significantly higher K2O/Na2O ratios than typical adakites. These three granites were probably derived from the partial melting of Precambrian continental crustal sources heated by upwelling asthenosphere in lithospheric extensional setting. Regionally, both the Alxa Block and the southeastern CAOB are characterized by the formation of early Carboniferous extension-related magmatic rocks but lack coeval sedimentary deposits, suggesting a uniform lithospheric extensional setting rather than a simple continental arc.