In this paper, an unmanned bicycle (UB) with a reaction wheel is designed, and a second-order mathematical model with uncertainty is established. In order to achieve excellent balancing performance of the UB system, an adaptive controller is designed, which is composed of nominal feedback control, compensating control using extreme learning machine observer and reaching control via integral terminal sliding mode (ITSM) and barrier function (BF)-based adaptive law. Owing to the features of BF-based ITSM (BFITSM), not only any uncertainty or disturbance upper bound is not needed any longer but also the finite-time convergence of the closed-loop system can be ensured with a predefined error bound. Moreover, the BF-based control gain can be adaptively adjusted according to the update of the lumped uncertainty such that the overestimation is removed. The stability analysis of the closed-loop system is given according to Lyapunov theory. Comparable experimental results on an actual UB are carried out to validate the superior balancing performance of the proposed controller.

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.

Numerous Late Carboniferous – Early Permian dykes are found in West Junggar and represent an important part of the Central Asian Orogenic Belt. In this contribution, we use these dykes to assess the tectonic regime and stress state in the Late Carboniferous – Early Permian. The West Junggar dykes are mainly diorite/dioritic porphyrite with minor diabase and were formed in 324–310 Ma. They have been divided into two groups based on their orientation, petrology and geochronology. Group 1 dykes mostly comprise WNW-striking dioritic porphyrite and NE-striking diorite with minor diabase and resemble the Karamay-Baogutu sanukitoid. They were probably formed from depleted mantle at a relatively high temperature and pressure with the addition of 1–2% sediment/sedimental partial melt and 0–5% trapped oceanic crust-derived melts. Group 2 dykes are ENE-striking and are similar to sanukite in the Setouchi Volcanic Belt. These dykes were also derived from depleted mantle at a shallow depth but high temperature with the addition of 2–3.5% sediment/sedimental partial melt. Magma banding and injection folds in dykes and host granitoids indicate magma flow. Paleostress analysis reveals that both groups of dykes were formed in a tensile stress field. Their emplacement is favoured by presence of pre-existing joints or fractures in the host granitoids and strata. We conclude that large-scale asthenosphere mantle upwelling induced by trapped oceanic slab-off can explain the magmatism and significant continental crustal growth of West Junggar during Late Carboniferous to Early Permian.

Pyrophyllite is an important layered phyllosilicate material that is used in many fields due to its beneficial physicochemical and mechanical properties. Due to the presence of multiple defects in pyrophyllite, an in-depth investigation was conducted using density functional theory to explore the effects of Na(I), K(I), Mg(II), Ca(II) and Fe(II) doping on the atomic structure, electronic properties and mechanical characteristics of pyrophyllite. The results demonstrated that, among the studied defects, K(I) doping had the most pronounced effects on the lattice constants and bonding lengths of pyrophyllite, while the least significant effects were observed in the case of Fe(II) doping. Moreover, the partial and total densities of states and band structures of the five kinds of doped pyrophyllite also changed significantly due to the redistribution of electrons. Finally, the elastic constants of the doped pyrophyllite were lower than that of the undoped pyrophyllite. Doping with Na(I), K(I), Mg(II), Ca(II) and Fe(II) reduced the deformation resistance, stiffness and elastic wave velocity but increased the degree of anisotropy in pyrophyllite. The observed effects on the mechanical properties of pyrophyllite followed the order: Mg(II) > Fe(II) > Ca(II) >K(I) > Na(I).

This paper presents systematic molecular dynamics modelling of Na-montmorillonite subjected to uniaxial compression and unidirectional shearing. An initial 3D model of a single-cell Na-montmorillonite structure is established using the Build Crystal module. The space group is C2/m, and COMPASS force fields are applied. Hydration analysis of Na-montmorillonite has been performed to validate the simulation procedures, where the number of absorbed water molecules varied with respect to the various lattice parameters. A series of uniaxial compression stress σzz and unidirectional shear stress τxy values are applied to the Na-montmorillonite structure. It is shown that the lattice parameter and hydration degree exhibit significant influence on the stress–strain relationship of Na-montmorillonite. The ultimate strain increases with increases in the lattice parameter but decreases in the number of water molecules. For saturated Na-montmorillonite, more water molecules result in a stiffer clay mineral under uniaxial compression and unidirectional shearing.

The pandemic caused by severe acute respiratory syndrome coronavirus 2 is sweeping the world, threatening millions of lives and drastically altering our ways of living. According to current studies, failure to either activate or eliminate inflammatory responses timely and properly at certain stages could result in the progression of the disease. In other words, robust immune responses to coronavirus disease 2019 (COVID-19) are critical. However, they do not theoretically present in some special groups of people, including the young, the aged, patients with autoimmunity or cancer. Differences also do occur between men and women. Our immune system evolves to ensure delicate coordination at different stages of life. The innate immune cells mainly consisted of myeloid lineage cells, including neutrophils, basophils, eosinophils, dendritic cells and mast cells; they possess phagocytic capacity to different degrees at different stages of life. They are firstly recruited upon infection and may activate the adaptive immunity when needed. The adaptive immune cells, on the other way, are comprised mainly of lymphoid lineages. As one grows up, the adaptive immunity matures and expands its memory repertoire, accompanied by an adjustment in quantity and quality. In this review, we would summarise and analyse the immunological characteristics of these groups from the perspective of the immune system ‘evolution’ as well as ‘revolution’ that has been studied and speculated so far, which would aid the comprehensive understanding of COVID-19 and personalised-treatment strategy.

This study aimed to evaluate the performance of Cobas human papillomavirus (HPV) test in cervical cancer screening. A total of 3442 women aged ⩾20 years used Cobas HPV and hybrid capture 2 (HC2) tests were included in this study. Women with any positive result were examined by liquid-based cytology (LBC) test. Then subjects with abnormal LBC or positive Cobas HPV16/18 were further checked by colposcopy to observe the visible lesions to perform the pathological examination. Of these 3442 women, 328 cases were Cobas HPV positive, and the positive rate was 9.53% (95% confidence interval (CI) 8.50–10.53). The positive rate of HPV16, HPV18, and other 12 types of high-risk HPV were 1.54% (95% CI 1.12–1.95), 0.55% (95% CI 0.30–0.80), and 7.44% (95% CI 6.56–8.32), respectively. The coincidence rate of Cobas HPV test and HC2 test was 90% (95% CI 89.00–91.00; Kappa = 0.526) in the primary screening. Age had a non-linear relationship with Cobas HPV positive rate (χ2 = 4.240, P = 0.040) and HPV16/18 typing positive rate (χ2 = 6.610, P = 0.010). Compared with the LBC test, the Cobas HPV test had higher sensitivity when detecting patients with high cervical intraepithelial neoplasia (CIN2+ and CIN3+).

Anatase phase NOx/S6+–TiO2 (x= 0, 1) film with high solar-driven activity has been successfully prepared via electro-assisted oxidation processes. The morphological and structural properties of the film were characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction, while the optical property was detected by UV-vis-NIR absorption spectroscopy. The results showed that the NOx/S6+–TiO2 film was composed of “flower-like” microvoids structure and displayed broad and strong optical absorption at around 544 and 1500 nm. Transient photocurrent response, photoluminescence spectroscopy, and electrochemical impedance spectroscopy indicated that the generation and separation of photogenerated charges were significantly enhanced under simulated solar irradiation. The NOx/S6+–TiO2 film exhibited excellent photoelectrocatalytic activity for the degradation of methyl orange (MO), and the decoloration rate and TOC removal respectively reached 98.97 and 59.44% at 20 min under solar irradiation. The film still had good stability after reusing ten times. Furthermore, a possible mechanism of photoelectrocatalysis was suggested in MO degradation by using NOx/S6+–TiO2 film.

GH3536 alloy is one of the high-temperature nickel-based alloys and widely applied in aviation and aerospace industries. In this study, a combination of experiment and simulation is proposed to study the effect of processing parameters on the selective laser melting (SLM) of GH3536 powder. It is concluded that the relationship between density and laser input energy during SLM complies with a quadratic function and presents an inverted U-shaped distribution. By fitting density and input power to a quadratic polynomial, the optimal laser input energy during SLM of GH3536 alloy can be obtained. The result shows that using 275 W laser power and 960 mm/s scanning speed, the SLM GH3536 specimens can reach the maximum density. This experimental result is consistent with the simulation result obtained by analyzing molten pool dimension. Furthermore, a full process energy prediction diagram for SLM GH3536 alloy based on the simulated molten pool depth and width is proposed. The result shows that it provides an innovative and efficient method for the selection of processing parameters during SLM of GH3536 powder.

Evidence on the association between maternal Hb concentration and preterm birth (PTB) risk is inconclusive. This paper aimed to explore whether women with anaemia or high Hb level before pregnancy would be at higher risk of PTB. We conducted a population-based cohort study with 2 722 274 women aged 20–49 years, who participated in National Free Pre-Pregnancy Checkups Project between 2013 and 2015 and delivered a singleton before 2016 in rural China. Logistic models were used to estimate OR and 95 % CI after adjusting for confounding variables. Restricted cubic spline models were applied to evaluate the dose–response relationships. A total of 192 819 (7·08 %) women had preterm deliveries. Compared with women with Hb of 110–149 g/l, the multivariable-adjusted OR for PTB was 1·19 (95 % CI 0·98, 1·44) for women with Hb<70 g/l, 1·01 (95 % CI 0·97, 1·03) for 70–99 g/l, 0·96 (95 % CI 0·95, 0·98) for 100–109 g/l, 1·04 (95 % CI 1·01, 1·06) for 150–159 g/l, 1·11 (95 % CI 1·05, 1·17) for 160–169 g/l and 1·19 (95 % CI 1·11, 1·27) for ≥170 g/l, respectively. The multivariable-adjusted OR for very PTB (VPTB) was 1·07 (95 % CI 1·03, 1·12) and 1·06 (95 % CI 1·01, 1·12) for women with Hb <110 and ≥150 g/l, compared with those with Hb of 110–149 g/l, respectively. Our study identified a U-shaped relationship between maternal preconception Hb concentration and PTB risk. Both preconception anaemia and high Hb level can significantly increase VPTB risk. Appropriate intervention for women with abnormal Hb levels before pregnancy is very necessary.

In this work, differential scanning calorimetry (DSC) was used to characterize and analyze the precipitation/dissolution kinetics of second phase particles during the cooling/reheating process in a vanadium microalloyed steel. The results indicated that three obvious exothermic peaks were detected on the cooling DSC curve. Furthermore, three corresponding endothermic peaks were also detected on the heating DSC curve. Combined with thermodynamic calculation and transmission electron microscopy analysis, these three exothermic peaks along cooling DSC curve were defined as the precipitation reaction of V(CN), the reaction of austenite transformation into ferrite and the precipitation reaction of VC, respectively. Meanwhile, three corresponding reverse reactions for cooling were also defined along the reheating DSC curve. The linear regression result revealed that the precipitation activation energies for V(CN) and VC were identified as 311.2 kJ/mol and 167.6 kJ/mol, respectively. The dissolution activation energies for VC and V(CN) were identified as 255.4 kJ/mol and 592.6 kJ/mol, respectively.

This work was aimed to use the peak separation method to directly measure the critical temperatures and phase transition fractions of austenite decomposition products based on experimental dilatometric curves in hypo-eutectoid steels. The results indicated that pearlite transformation start temperature and ferrite transformation finish temperature could be clearly obtained through peak separation processing, which were generally hidden in the overlapped peaks of the linear thermal expansion coefficient curve. Moreover, four critical temperatures of austenite decomposition were retarded to lower temperature with cooling rate increasing. The phase transition fraction for austenite decomposition was quantitated by measuring the area of the corresponding phase transformation peak. The final ferrite phase fraction after austenite decomposition decreased with cooling rate increasing. On the contrary, the final pearlite phase fraction increased with cooling rate increasing. Compared with the lever rule, the calculation result using peak area method can accurately reflect the actual phase fraction change versus the temperature during austenite decomposition.

As a unique tubular nanoclay, halloysite nanotubes (HNTs) have recently attracted significant research attention. The HNTs have outer diameters of ∼50 nm, inner lumens of ∼20 nm and are 200–1000 nm long. They are biocompatible nanomaterials and widely available in nature, which makes them good candidates for application in biomedicine. Compared with other types of nanoparticles such as polymer nanoparticles and carbon nanotubes, the drawbacks associated with HNTs include brittleness, difficulty with fabrication, low fracture strength, high density and inadequate biocompatibility. Preparation of polysaccharide-HNT composites offer a means to overcome these shortcomings. Halloysite nanotubes can be incorporated easily into polysaccharides via solution mixing, such as with chitosan (CS), sodium alginate, cellulose, pectin and amylose, for forming composite films, porous scaffolds or hydrogels. The interfacial interactions, such as electrostatic attraction and hydrogen bonding, between HNTs and the polysaccharides are critical for improvement of the properties. Morphology results show that HNTs are dispersed uniformly in the composites. The mechanical strength and Young's modulus of the composites in both the dry and wet states are enhanced by HNTs and the HNTs can also increase the storage modulus, glass-transition temperature and thermal stability of the composites. Cytocompatibility results demonstrate that the polysaccharide-HNT composites have low cytotoxicity even for HNT loading >80%. Therefore, the polysaccharide-HNT composites show great potential for biomedical applications, e.g. as tissue engineering scaffold materials, wound-dressing materials, drug-delivery carriers, and cell-isolation surfaces.

Drawing from self-concept and implicit leadership theories, we propose a multilevel model to examine whether, why, and when self-sacrificial leadership motivates followers’ affiliative and challenging citizenship behaviors in China. Data from 329 full-time employees in 83 work groups provide support for the hypothesized model. Specifically, we demonstrated that self-sacrificial leadership was positively related to followers’ relational self-concept constructs of leader identification and leader-based self-esteem, which had differential, downstream implications for followers’ two types of citizenship behavior. Whereas leader identification was found to mediate the positive relationship between self-sacrificial leadership and affiliative citizenship behavior only, leader-based self-esteem mediated the positive relationships of self-sacrificial leadership with both affiliative and challenging citizenship behaviors. We further demonstrated individual power distance orientation as a significant cultural contingency in the above mediation relationships, which were found to exist among followers with low rather than high power distance orientations. We conclude by discussing the theoretical and practical implications of these findings.

For Sn–Pb eutectic solder alloy, uniaxial tensile tests were conducted to dog-bone type specimens annealed at different temperatures (60–180 °C) and durations (2–48 h). Low strain rates ranging from 10−4 s−1 to 10−3 s−1 were applied to study the competition between creep and plasticity and also the rate dependent effect of annealing condition. It is found that the influence of annealing temperature on material properties is more than that of annealing duration. Higher temperature up to 180 °C generally leads to higher yield and ultimate stresses and ultimate strain of annealed specimens. The optimal annealing condition is suggested to be 180 °C for 6 h for stable and efficient improvements in both strength and ductility. By proposing a concise unified creep and plasticity constitutive model, the sensitivity to strain rate and annealing condition is quantified with consideration of both creep and hardening properties. Parameter calibration theoretically confirms the observed optimal annealing condition in experiments.

The Be-based materials with many particular properties lead to an important research subject. The investigation progresses in the fabrication technologies are introduced here, including main three kinds of Be-based materials, such as Be–Cu capsule, $\text{Be}_{2}\text{C}$ ablator and high-purity Be material. Compared with the pioneer workgroup on Be-based materials, the differences in Be–Cu target fabrication were described, and a grain refinement technique by an active hydrogen reaction for Be coating was proposed uniquely. $\text{Be}_{2}\text{C}$ coatings were first prepared by the DC reactive magnetron sputtering with a high deposition rate $({\sim}300~\text{nm}/\text{h})$. Pure polycrystalline $\text{Be}_{2}\text{C}$ films with uniform microstructures, smooth surface, high density $({\sim}2.2~\text{g}\cdot \text{cm}^{3})$ and good optical transparency were fabricated. In addition, the high-purity Be materials with metal impurities in a ppm magnitude were fabricated by the pyrolysis of organometallic Be.

The Myanmar snub-nosed monkey Rhinopithecus strykeri was discovered in 2010 on the western slopes of the Gaoligong Mountains in the Irrawaddy River basin in Myanmar and subsequently in the same river basin in China, in 2011. Based on 2 years of surveying the remote and little disturbed forest of the Gaoligong Mountains National Nature Reserve in China, with outline transect sampling and infrared camera monitoring, a breeding group comprising > 70 individuals was found on the eastern slopes of the Gaoligong Mountains in the Salween River Basin. Given the Critically Endangered status of this primate (a total of < 950 individuals are estimated to remain in the wild), efforts to protect the relatively undisturbed habitat of this newly discovered population and to prevent hunting are essential for the long-term survival of this species.