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This study employs direct numerical simulations to examine the effects of varying backpressure conditions on the turbulent atomisation of impinging liquid jets. Using the incompressible Navier–Stokes equations, and a volume-of-fluid approach enhanced by adaptive mesh refinement and an isoface-based interface reconstruction algorithm, we analyse spray characteristics in the environments with ambient gas densities ranging from 1 to 40 times the atmospheric pressure under five different backpressure scenarios. We investigate the behaviour of turbulent jets, incorporate realistic orifice geometries and identify significant variations in the atomisation patterns depending on backpressure. Two distinct atomisation types emerge, namely jet-sheet-ligament-droplet at lower backpressures and jet-sheet-fragment-droplet at higher ones, alongside a transition from dilute to dense spray patterns. This variation affects the droplet size distribution and spray dynamics, with increased backpressure reducing the spray's spreading angle and breakup length, while increasing the droplet size variation. Furthermore, these conditions promote distributions that induce rapid, nonlinear wavy motion in liquid sheets. Topological analysis of the atomisation field using velocity-gradient tensor invariants reveals significant variations in topology volume fractions across different regions. Downstream, the droplet Sauter mean diameter increases and then stabilises, reflecting the continuous breakup and coalescence processes, notably under higher backpressures. This research underscores the substantial impact of backpressure on impinging-jet atomisation and provides essential insights for nozzle design to optimise droplet distributions.
In the control of space robots, flexible vibrations exist in the base, links and joints. When building a motion control scheme, the following three aspects should be considered: (1) the complexity in dynamic modeling; (2) the low accuracy of motion control and (3) the simultaneous suppression of multiple flexible vibrations. In this paper, we propose a motion vibration integrated saturation control scheme. First, the dynamic model of space robot with flexible-base, flexible-link and flexible-joint is established according to the assumed modes method and Lagrange equation. Second, singular perturbation theory is used to decompose the model into two subsystems: a slow subsystem containing the rigid motions of base and joints as well as the vibration of links, and a fast subsystem containing vibrations of base and joints. Third, an integrated sliding mode control with input restriction, output feedback and repetitive learning (ISMC-IOR) is designed, which can track the desired trajectories of base and joints with −3 orders of magnitude accuracy, while suppressing the multiple flexible vibrations of base, links and joints 50%–80% and 37% performance improvement over ISMC-IOR-NV were achieved. Finally, the algorithm is verified by simulations.
The aim of this study was to investigate the changes in Chinese residents’ psychological state and its influencing factors after the Wuhan shutdown on January 23, 2020.
Methods:
Two surveys were conducted on February 1-5 and February 20-24, separately, using an online self-administrated questionnaire among 3145 and 3814 participants, respectively. Subjective indicators of daily-life changes include level of attention, risk of infection, impact of daily life, self-perceived health status, and mental health help-seeking. Individual scores on changes in anxiety, depression, and stress were generated by 6-item, 4-item, and 3-item questions. A multivariate regression model was fitted in each survey, separately and combined.
Results:
A total of 6959 residents participated in the study, with 32.78% male and 67.22% female, people living in Wuhan and other cities in Hubei Province accounted for 25.22% and 18.85%, respectively. One week after the Wuhan shutdown, their anxiety, depression, and stress had all increased. Compared with the first survey, the changes in the scores of anxiety, depression, and stress in the second survey were decreased (β = −1.220, −0.798, and −0.623, all P < 0.001). The level of attention, risk of infection, and self-perceived health status tended to be positively associated with the changes in the scores of anxiety, depression, and stress.
Conclusions:
The study showed that the lives and psychological conditions of residents had undergone negative changes after the Wuhan shutdown, but the measures taken during this period were effective. These results may provide guidance for public health policies in other countries and regions.
Understanding the patterns of treatment response is critical for the treatment of patients with schizophrenia; one way to achieve this is through using a longitudinal dynamic process study design.
Aims
This study aims to explore the response trajectory of antipsychotics and compare the treatment responses of seven different antipsychotics over 6 weeks in patients with schizoprenia (trial registration: Chinese Clinical Trials Registry Identifier: ChiCTR-TRC-10000934).
Method
Data were collected from a multicentre, randomised open-label clinical trial. Patients were evaluated with the Positive and Negative Syndrome Scale (PANSS) at baseline and follow-up at weeks 2, 4 and 6. Trajectory groups were classified by the method of k-means cluster modelling for longitudinal data. Trajectory analyses were also employed for the seven antipsychotic groups.
Results
The early treatment response trajectories were classified into a high-trajectory group of better responders and a low-trajectory group of worse responders. The results of trajectory analysis showed differences compared with the classification method characterised by a 50% reduction in PANSS scores at week 6. A total of 349 patients were inconsistently grouped by the two methods, with a significant difference in the composition ratio of treatment response groups using these two methods (χ2 = 43.37, P < 0.001). There was no differential contribution of high- and low trajectories to different drugs (χ2 = 12.52, P = 0.051); olanzapine and risperidone, which had a larger proportion in the >50% reduction at week 6, performed better than aripiprazole, quetiapine, ziprasidone and perphenazine.
Conclusions
The trajectory analysis of treatment response to schizophrenia revealed two distinct trajectories. Comparing the treatment responses to different antipsychotics through longitudinal analysis may offer a new perspective for evaluating antipsychotics.
Nitrogen is an important element for the growth of flue-cured tobacco and is closely related to its yield and quality. In order to pursue higher economic benefits, excessive fertilizer is generally applied in flue-cured tobacco production, which is unfavourable for the sustainable development of flue-cured tobacco production and for the environment. In 2016 and 2017, experiments using different nitrogen fertilizer application rates in flue-cure tobacco were conducted in Yunnan province, and the changes in agronomic, economic and chemical indices as well as in residual soil nitrogen were compared. Linear and quadratic models were used to compare the response of tobacco to nitrogen fertilizer. With increasing nitrogen fertilizer rate, the proportions of superior to medium tobacco and the average price of flue-cured tobacco leaves initially increased and then decreased, while fresh weight, dry weight and the proportion of inferior tobacco showed the opposite trend. Total sugar and reducing sugar contents decreased with increasing nitrogen fertilizer rates, while total nitrogen and nicotine contents increased. Sensory evaluation scores had the highest value when 90 kg N/ha and 120 kg N/ha were applied. Soil nitrate contents increased as nitrogen fertilizer rate increased. The quadratic model was suitable for the response of cultivar K326 to nitrogen and 90 kg N/ha could meet the needs of cultivar K326.
We report on a high-power Ho:YAG single-crystal fiber (SCF) laser inband pumped by a high-brightness Tm-fiber laser at 1908 nm. The Ho:YAG SCF grown by the micro-pulling-down technique exhibits a propagation loss of $0.05\pm 0.005~\text{cm}^{-1}$ at $2.09~\unicode[STIX]{x03BC}\text{m}$. A continuous-wave output power of 35.2 W is achieved with a slope efficiency of 42.7%, which is to the best of our knowledge the highest power ever reported from an SCF-based laser in the 2 $\unicode[STIX]{x03BC}\text{m}$ spectral range.
To explore the scope of metabolic syndrome (MetS) and its relationship to the major dietary patterns among an urbanised and semi-urbanised Tibetan population in transition from nomadic to settled settings.
Design:
Cross-sectional.
Setting:
Community-based.
Participants:
Urbanised and semi-urbanised Tibetan adults (n 920, aged 18–90 years), who have moved from nomadic to settled living environments, answered questionnaires on food consumption frequency and lifestyle characteristics through structured face-to-face interviews and completed anthropometric measurement and metabolic biomarker tests.
Results:
MetS prevalence was 30·1 % in males and 32·1 % in females. Low HDL-cholesterol and central obesity were the leading metabolic abnormalities (86·3 and 55·8 %, respectively). Three major dietary patterns – urban, western and pastoral – were identified. Beef/mutton was an important food group for all three identified dietary patterns. In addition, the urban dietary pattern was characterised by frequent consumption of vegetables, tubers/roots and refined carbohydrates; the western pattern was characterised by sweetened drinks, snacks and desserts; and the pastoral pattern featured tsamba (roasted Tibetan barley), Tibetan cheese, butter tea/milk tea and whole-fat dairy foods. Individuals in the highest quintile of urban dietary pattern scores were found to be at a higher risk of developing MetS (OR 2·43, 95 % CI 1·41, 4·18) and central obesity (OR 1·91, 95 % CI 1·16, 3·14) after controlling for potential confounders.
Conclusions:
MetS was common among urbanised and semi-urbanised Tibetan adult population in transition. The urban dietary pattern, in particular, was a risk factor for MetS. To prevent MetS, nutrition interventions need to be tailored to address the variety of local diet patterns to promote healthy eating.
Sea ice is composed of columnar-shaped grains. To investigate the influence of the loading direction on the uniaxial compressive strength and failure processes of sea ice, field experiments were performed with first-year level ice. Loads were applied both horizontally (parallel to the grain columns) and vertically (across the grain columns) with various nominal strain rates. Two failure modes have been observed: a ductile failure mode at low nominal strain rates, and a brittle failure mode at high nominal strain rates. However, the failure pattern of sea ice was clearly dependent on the loading direction. At low nominal strain rates (ductile failure mode), the sea-ice samples yielded due to the development of wing cracks under horizontal loading and due to splaying out at one end under vertical loading. When sea ice fails in the ductile mode, the deformation is driven by grain boundary sliding under horizontal loading and by grain decohesion and crystal deflection under vertical loading. At high nominal strain rates (brittle failure mode), the sea-ice samples failed in shear faulting under horizontal loading and in cross-column buckling under vertical loading. The nominal strain rate at the brittle–ductile transition zone is about ten times higher under vertical loading.
In this paper, the atomic resolution high-angle annular dark-field scanning transmission electron microscope (HAADF-STEM) was used as the main research method. Using HAADF-STEM, two types of long-period stacking ordered structure (LPSO)—14H and 18R-LPSO—were observed in Mg96Gd2Y1Ni1 alloy, and the precipitates at various stages of aging were observed. Moreover, a type of rectangular β precipitates were found, and the atomic models of β precipitates along the [0001]Mg and ${\tf="TeXGyrePagella-Bold (TrueType)"\char9001} 11\bar 20\hbox{]}_{{\rm{Mg}}}$ directions were identified. At the aging peak stage, a three-dimensional network structure composed of LPSO/γ′ precipitates and β′ precipitates and β precipitates was observed. The hardness of the unaged homogenized Mg96Gd2Y1Ni1 alloy was only 87 HV and the hardness value of aging peak was 128.4 HV. Compared with the unaged alloy, the hardness of the peak-aged alloy increased by 47.59%. The composite strengthening of the three types of precipitates induced a significant strengthening to the alloy.
We study the breakup of confined fluid threads at low flow rates to understand instability mechanisms. To determine the critical conditions between the earlier quasi-stable necking stage and the later unstable collapse stage, simulations and experiments are designed to operate at an extremely low flow rate. The critical mean radii at the neck centres are identified by the stop-flow method for elementary microfluidic configurations. Two distinct origins of capillary instabilities are revealed for different confinement situations. One is the gradient of capillary pressure induced by the confinements of geometry and external flow, whereas the other is the competition between the capillary pressure and internal pressure determined by the confinements.
Aging treatment plays an important role in strengthening of 2198 Al–Li alloy. Through a serious of heat treatment processes, a large amount of precipitates emerge, mainly observed to be θ′(Al2Cu), Al3Zr, and T1(Al2CuLi), among which, T1 turns to be the most important precipitate that contributes to the strengthening of 2198 Al–Li alloy. While the temperature of the aging process is 175 °C, the density and size of T1 phase keep increasing through the process and reach peak in about 18 h. T1 phase tends to have a certain orientation relationship of ${\left( {0001} \right)_{{{\rm{T}}_1}}}//{\left\{ {111} \right\}_{{\rm{Al}}}}$, ${\left\langle {1010} \right\rangle _{{{\rm{T}}_{\rm{1}}}}}//{\left\langle {110} \right\rangle _{{\rm{Al}}}}$ and may have different kinds of multilayered structures. In most of the multilayered structures, the distance between two adjacent copper-rich laths is less than that in classical single-layered phase. Thus, it can be inferred that the microstructure of T1 phase might change in the process of developing from single-layered structure to multilayered structure. In addition, the interactions between different phases become relatively frequent when the density of T1 phase reaches a threshold.
A field study to optimize the nitrogen (N) top-dressing mode of panicle fertilization and improve rice yields was conducted in mid-eastern China. Japonica cultivar Yunongjing-6 was grown and panicle N fertilizer was applied at the beginning of the inverted fourth leaf stage using three different modes: manual broadcast application (BA) on the soil surface as a control treatment, deep application during ditching at a depth of 15 cm (DD) and manual BA on the soil surface during deep ditching (BAD). The activity of soil enzymes, including invertase, urease, phosphatase and catalase, was increased significantly at the jointing, booting and grain-filling stages with the DD and BAD treatments compared with the traditional BA mode. The DD and BAD treatments also increased basal internode and neck-panicle internode bleeding intensity. The DD treatment gave the highest crop yield, increasing the yield by 0.63 and 0.31 t/hm2 in 2011 and 2012, respectively, compared with BA. The results suggest that ditching during panicle N fertilizer application after sun-drying of the fields increases rice yields, most likely by improving the activity of soil enzymes and enhancing the physiological activity of roots and grain weight.
Promoting environmentally conscious behaviour requires an understanding of the complex cognitive mechanisms by which people decide to act environmentally. Research suggests that locus of control (LOC), or the extent to which a person feels his or her own actions can produce broader change, is an important predictor of environmental behaviour; however, little is known about how LOC interacts with other cognitive motivators. This study uses a nationwide survey from China to test whether LOC moderates the effect of environmental attitudes on behaviour. Respondents with external LOC (i.e., those who believe personal actions cannot produce change) reported lower pro-environmental behaviour than those with internal LOC (i.e., those who believe personal actions can produce change). In addition, the influence of environmental attitudes on pro-environmental behaviour was stronger among respondents with external LOC than those with internal LOC. These results support efforts to promote conservation in China by promoting internal LOC and add a novel suggestion that attitude-based messaging is more efficacious among audiences with external LOC.
Underground Nuclear Astrophysics in China (JUNA) will take the advantage of the ultra-low background in Jinping underground lab. High current accelerator with an ECR source and detectors were commissioned. JUNA plans to study directly a number of nuclear reactions important to hydrostatic stellar evolution at their relevant stellar energies. At the first period, JUNA aims at the direct measurements of 25Mg(p,γ)26 Al, 19F(p,α) 16 O, 13C(α, n) 16O and 12C(α,γ) 16O near the Gamow window. The current progress of JUNA will be given.
Hot deformation behavior and microstructure evolution of as-cast Mn18Cr18N austenitic stainless steel were investigated by isothermal compression experiments. The results indicate that the microstructure evolution of the as-cast Mn18Cr18N steel is sensitive to strain rates. Discontinuous dynamic recrystallization, characterized by nucleation and growth controlled by grain boundary migration, occurs at lower strain rates. However, higher strain rates result in higher adiabatic temperature rise, which could be contributed to dynamic recrystallization (DRX) nucleation and growth by acceleration boundary migration. In addition, at higher strain rates, a large number of deformation microbands in the interior of coarse columnar grains were observed, which would provide potential nucleation sites for DRX. Meanwhile, a great number of Σ3 twins were observed, which reveals that twinning accelerates the separation of subgrains from bulging grain boundaries, and the iterative processing among Σ3 twins and its variants promotes the transformation from specific CSL grain boundaries to random high-angle boundaries.
Formation of a nanometer-scale oxide surface layer is common when a material is exposed to oxygen-containing environment. Employing aberration-corrected analytical transmission electron microscopy and using single crystal SnSe as an example, we show that for an alloy, a second thin amorphous layer can appear underneath the outmost oxide layer. This inner amorphous layer is not oxide based, but instead originates from solid-state amorphization of the base alloy when its free energy rises to above that of the metastable amorphous state; which is a result of the composition shift due to the preferential depletion of the oxidizing species, in our case, the outgoing Sn reacting with the oxygen atmosphere.