Three-dimensional effects of sidewalls on the low-frequency unsteadiness of the shock-wave/boundary-layer interaction (SBLI) are of academic and practical importance but not yet well understood. Considerable attention has been paid to the viscous effect of sidewalls, whereas the potential inviscid confinement effect of sidewalls has received little attention. The present work provides experimental evidence of multiscale spanwise travelling waves crossing the separation front under the confinement of sidewalls. Global pressure measurements were made for a sidewall-confined 24$^\circ$ compression ramp interaction in Mach-2.83 flow using fast-responding pressure-sensitive paint. The unsteady pressure in a statistically two-dimensional intermittent region suggests that in addition to the canonical streamwise oscillation, the separation front exhibits significant low-frequency, multiscale spanwise distortion. Modal analysis further reveals that multiscale spanwise unsteadiness has higher intensity and frequency than the streamwise oscillation. Such strong spanwise unsteadiness calls attention to the low-frequency unsteadiness in previous sidewall-confined SBLI experiments and encourages further study on the mechanism of the confinement effect.

Participation in social activities might increase older adults’ chances to interact with other people and has been found to be important in reducing the likelihood of depression. A picture of older adults’ attitudes towards ageing and their self-esteem constructed through the lens of how they interact with other people might cast light on the sources of older adults’ depression. This study explored the influences of social participation and attitudes towards ageing on depression of Chinese older adults. Using two waves data from the China Longitudinal Ageing Social Survey (CLASS) in 2014 and 2016 (6,908 participants in 2014 and 3,477 participants in both 2014 and 2016), we found that social participation in 2014 could prevent the risk of depression in both the 2014 and 2016 cohorts. In addition, both psychosocial loss and psychosocial growth in 2014 were negatively associated with depression in both 2014 and 2016. However, there was no evidence that social participation moderated the relationship between attitudes towards ageing and depression in either cohort. Social policies need to encourage older adults’ conversion from ‘passive participation’ to ‘active participation’. This could help older adults understand the process of ageing and their value to society, as well as have positive effects on older adults’ mental health.

Increasing evidence has shown that an active, socially engaged lifestyle in leisure time might protect older adults against the decline of cognitive function. It remains unclear, however, which types of leisure activities are more beneficial to maintain cognitive function, and whether there are gender differences in the association between leisure activities and cognitive function. We used a two-wave of panel data from 1,018 older adults aged 60 and older in rural China to examine the lag effects of different types of leisure activities on cognitive functioning and to identify the gender differences in their impacts on cognition in rural China. Ordinary least-squares regression models showed that high physical activities were associated with better cognitive function. High intensity of cognitive activities and engaging in physical activities have a protective effect on cognitive function among older men rather than older women. Further, we found that cognitive activities had a stronger effect on cognitive function among older men than older women. It is important to consider gender-specific intervention in leisure activities to maintain cognitive function among older adults.

Life expectancy in China has increased. This paper explores the age when older adults (aged 60 and above) consider themselves to be an ‘older person’ and how age-related loss of resources (five dimensions: early cumulative factors, decline and loss of health resources, reduction and loss of economic resources, weakening and loss of social support resources, and personal role transition and experiences of losing family members) could impact their perceived old age. Using two waves of data from the China Longitudinal Ageing Social Survey (CLASS) in 2014 and 2016 (6,244 participants in 2014 and 2,989 participants in both 2014 and 2016), we found that the mean perceived old age is around 70 years at baseline (2014). Higher level of educational attainment and occupational types (early cumulative factors), better health condition, receiving support from friends and taking care of grandchildren are significantly associated with the perception that old age begins at an older age at baseline, while being Han-Chinese, being an urban resident (early cumulative factors) and reporting better health condition have significant positive effects on the perception that old age begins at an older age in the later wave. Our findings suggest that the age standard of older adults should be adjusted dynamically in response to social development and longevity, and also highlight the importance of early cumulative factors in shaping the ageing process besides age-related factors.

Increased mortality after spousal bereavement has been observed in many populations. Few studies have investigated the widowhood effect in a traditional culture where the economy is underdeveloped. The reasons for the widowhood effect and its gender dynamic are not well understood. In this study, we assessed whether the widowhood-associated excess mortality exists and differs by gender and living arrangement in rural China. We used a six-wave panel of data derived from rural people over 60 years old in the Chaohu region of China. Cox regression analyses suggest that there was a positive effect of spousal loss on mortality for older rural Chinese and this effect was gender different. Our findings also suggest that living with adult children after spousal loss played a protective role in reducing the risk of older men's death, though it tended to increase older men's mortality risk in general.

The turbulent–non-turbulent interface (TNTI) of supersonic turbulent boundary layers is a fundamental but relatively unexplored physics problem. In this study, we present experimental results from fractal analysis on the TNTI of supersonic turbulent boundary layers, and test the applicability of the additive law for these flows. By applying the nanoparticle-tracer planar laser scattering (NPLS) technique in a supersonic wind tunnel, we obtain data covering nearly three decades in scale. The box-counting results indicate that the TNTI of supersonic turbulent boundary layers is a self-similar fractal with a fractal dimension of 2.31. By comparing data sets acquired from two orthogonal planes, we find that the scaling exponent does not depend on direction, consistent with the validity of the additive law for the TNTI of turbulent boundary layers in a scale range with the large-scale limit not exceeding approximately $0.05\unicode[STIX]{x1D6FF}$.

Previous studies have demonstrated adverse mental health effects of Pb exposure. The purpose of this study is to investigate the relationship between consumption of preserved egg (PE), a high-Pb-containing food and depressive symptoms among adults in China. A sample of 25 213 adults (mean age 41·4 (sd 11·8) years; males, 53·9 %) in Tianjin, China, was studied in a cross-sectional analysis. Dietary intake including PE was assessed using a valid self-administered FFQ. Depressive symptoms were assessed using the Self-Rating Depression Scale (SDS). The association was estimated by OR using logistic regression models adjusted for multiple confounders. The prevalence of elevated depressive symptoms was 6·6 % (SDS≥50). Compared with the least frequent PE consumption (<once/week), multivariable adjusted OR for elevated depressive symptoms were 1·52 (95 % CI 1·28, 1·81), 2·24 (95 % CI 1·76, 2·81) and 3·31 (95 % CI 2·52, 4·30) for consumption of once, 2–3 times and ≥4 times/week, respectively (Pfor trend<0·0001), indicating a clear dose–response relationship. The results suggested that higher consumption of PE was strongly associated with depressive symptoms among adults in China. These findings underscore the need to consider dietary Pb exposure as a risk factor for psychological distress.

The hot deformation behavior of Nb–V–Ti microalloyed ultra-high strength steel was investigated by isothermal compression at 900–1200 °C with strain rates from 0.01 to 10 s−1. The microstructure evolution and precipitation behavior were studied using an optical microscope and a transmission electron microscope Results indicate that the peak stress of experimental steel increases with increasing the strain rate and decreasing the deformation temperature. The constitutive equation of hot deformation was developed with the activation energy Q being about 407.29 kJ/mol. The processing maps were also obtained to identify the instable regions of the flow behavior and to evaluate the efficiency of hot deformation. The size of dynamically recrystallized grains increases gradually with a decrease in the strain rate. Three types of carbides were identified, namely M3C, rich-Ti MC, and rich-Nb MC. With the increase of the deformation rate, the amounts of carbides increase, and the average sizes of the carbides decrease gradually.

Laminate sheets attract increasing attention from researchers and engineers. In this paper, Al/Ti/Al laminate sheets were fabricated by using cryogenic roll bonding for first time. The edge defects, mechanical properties, and interface bonding of laminate sheets by cryogenic roll bonding technique were compared with these by room-temperature roll bonding technique. Results show that there are some edge cracks in laminate sheets by room-temperature roll bonding while they do not appear when subjected to cryogenic roll bonding. The ultimate tensile stress of laminate sheets by cryogenic roll bonding increases up to 36.7% compared to that by room-temperature roll bonding. When laminate sheets are rolled to 0.125 mm from 2.025 mm, the interfaces between Al and Ti layers are bonded well for both cryogenic roll bonding and room-temperature roll bonding. Finally, we discussed the improvement in edge quality and mechanical properties and the mechanism of interface bonding of Al/Ti/Al laminate sheets during cryogenic roll bonding.

Previous studies have supported the theory that there is a positive association between ferritin and carotid atherosclerosis in Western people. Diet plays an important role in determining serum ferritin concentration. Asian dietary patterns are different from Western dietary patterns, implying that there may be a difference in the association of ferritin with carotid atherosclerosis between Asian and Western people. However, few studies focus on the association between ferritin and carotid atherosclerosis among Asians. The aim of this study was to investigate how serum ferritin levels are associated with carotid atherosclerosis in an Asian adult population. A cross-sectional assessment was performed in 8302 adults in Tianjin, China. Carotid intima-media thickness (IMT) and plaques were assessed using ultrasonography, and serum ferritin was measured using the protein chip-chemiluminescence method. Multiple logistic regression analysis was used to examine the association between quartiles of serum ferritin concentration and carotid atherosclerosis. In the present study, the overall prevalence of IMT and carotid plaques in participants is 29·2 and 22·7 %, respectively. In women, after adjustments for potentially confounding factors, the OR of IMT and carotid plaques by increasing serum ferritin quartiles were 1·00, 1·39 (95 % CI 0·98–1·99), 1·39 (95 % CI 0·99–1·97), 1·81 (95 % CI 1·30–2·55) (Pfor trend<0·001) and 1·00, 1·24 (95 % CI 0·89–1·73), 1·18 (95 % CI 0·85–1·65), 1·59 (95 % CI 1·15–2·20) (Pfor trend<0·01), respectively. However, no association was found between serum ferritin and carotid atherosclerosis in men. The study demonstrated that increased serum ferritin levels are independently associated with IMT and carotid plaques in Asian women but not in Asian men.

The constitutive equation was established based on the consideration of strain compensation to describe the hot deformation behavior of low carbon reduced activation ferritic/martensitic (RAFM) steels at the temperatures of 850–1050 °C and the strain rates of 0.01–10 s−1. The result indicates that the flow stress is increased with the increase of strain rate but decreased with increase of deformation temperature. During the hot deformation process, the increase of temperature is beneficial to attain the complete dynamic recrystallization (DRX). However, excessively high temperature leads to grow up of dynamic recrystallized grain. Higher strain rate leads to finer recrystallized grains. The material constants (α, n, A) and deformation activation energy (Q) are calculated by the regression analysis. The increase of strain caused the decrease of Q, indicating the DRX occurred more easily. In addition, the developed constitutive equation could accurately predict the hot deformation behavior of the low carbon RAFM steel.

The dwarfing wheat (Triticum aestivum L.) breeding has promoted a dramatic increase in yields. Since the utilized dwarfing genes in wheat are very limited, identification of novel dwarfing genes is necessary for improving the genetic diversity of wheat. In this study, more than 300 dwarfing wheat lines from induced mutation were screened by kompetitive allele-specific PCR and gibberellin (GA) treatment. The 17.49% of Rht-D1b and 1.37% of Rht-B1b dwarfing mutants were identified in this mutant group. Additionally, Rht-D1b mutants showed more effective in reduction of plant height and higher 1000-grain weight comparing with that of Rht-B1b mutants. By combing with comparison of yield components and expression profile of GA biosynthetic genes with wild-type, the GA-responsive mutant dm15 without directly involvement in GA metabolism, significantly increased 1000-grain weight but no change of other yield components in two locations of field experiments. Meanwhile, another elite mutant dm11 with change of GA biosynthetic genes expression was also identified. These mutants will be promising candidates for dwarfing wheat breeding.

China is experiencing rapid urbanisation and population ageing, alongside sometimes contentious rural land consolidation. These on-going social, economic, political and demographic changes are especially problematic for older people in rural areas. In these regions, social and institutional support arrangements are less developed than in urban areas; older people have few options for re-settlement but are resistant to or incapable of adjusting to high-rise apartment living. In 2012–13, we gathered rich qualitative and quantitative data on over 600 older residents in 12 villages under the jurisdiction of City L in north-east coastal China to analyse residents’ living arrangement choices during the village renovation process. We compared villages with and without senior centres to shed light on the correlates of co-residence and independent living. Senior centres play a role in balancing the burden on rural Chinese families resulting from population ageing, smaller families, widespread migration for work, and the rapid urbanisation that is restructuring land rights and social support arrangements.

To study the hot deformation behavior of the Ti–22Al–25Nb alloy, isothermal compression tests were conducted at the temperature range of 930–1080 °C with strain rates of 0.001–1.0 s−1. Both the strain rate and the deformation temperature have a significant influence on the stress–strain behavior of the Ti–22Al–25Nb alloy. A hyperbolic–sine constitutive equation is established to quantitatively demonstrate the relationship between the parameters involved, and the hot deformation activation energy Q is determined as 621 kJ/mol. To optimize the processing window, a hot processing map is established, which is related to the microstructure evolution in hot working. The lamellar globularization as well as the dynamic recrystallization (DRX) would contribute to the stable regions with high power dissipation, while the adiabatic shear bands would lead to unstable regions. Moreover, an Avrami-type kinetics model is applied to examine the evolution of DRX during isothermal deformation process.

The microstructure evolution and mechanical properties of ultrafine-grained (UFG) Al sheets subjected to accumulative roll bonding (ARB) and subsequent cryorolling was studied. Cryorolling can suppress the dynamic softening of UFG Al sheets subjected to ARB at room temperature. After the third ARB pass, the grains are slightly refined as the number of ARB passes increases. However, the grains are significantly refined further during cryorolling. The grain size of 460 nm achieved after the third ARB pass is reduced to 290 nm after two cryorolling passes with total reduction ratio 80%. Sheets subjected to ARB + cryorolling show improved mechanical properties compared to only ARB-processed sheets due to a change in the fraction of high-angle boundaries and elongated grains. The deformation mechanism for ultrafine grains at room temperature is determined by grain boundary sliding or dislocation-based recovery, while it is governed by dislocation glide at cryogenic temperature.

The microstructural evolution of type 347H heat-resistant austenitic steel during long-term aging at 700–900 °C was investigated by using a transmission microscope, a scanning electron microscope, and electron energy spectrum technology. The microstructural examination showed the typical micrographs of MX carbonitrides and M23C6 carbides after aging. The existence of the Z phase (NbCrN) at the grain boundaries during aging was identified. Meanwhile, the possible precipitation sequence of these particles was also confirmed. In the beginning of aging, fine Nb(C,N) precipitates first, then, M23C6 carbides precipitate along the grain boundaries. Finally, the Z phase is also observed at the grain boundaries. Moreover, the influence of isothermal holding temperature on the precipitation of MX carbonitrides and M23C6 carbides was discussed. The various microstructural characterizations showed that the M23C6 carbides and MX carbonitrides precipitate more easily with the increase of aging temperature. Furthermore, the number and the size of MX particles and M23C6 carbides increase when the isothermal holding time is prolonged.

The influence of aging treatment on the shape memory effect and corrosion resistance of a newly developed Fe–Mn–Si–Cr–Ni-based alloy containing C, N, and V elements was investigated. Results showed that V(CN) and Cr23C6 particles, precipitated during aging, could improve the shape recovery ratio to 72%, compared with that of 21% for the solution treated sample, when the alloy was aged for 24 h. The corrosion behavior in 0.5 M H2SO4 solution was almost the same for all the samples, barring a slight difference in the passivation range. In addition, the passivation current and critical current required for the onset of passivation of the aged samples were almost triple that of the unaged. In 3.5% NaCl solution the corrosion behavior of all aged samples was that of general dissolution with localized attack (pitting), which can be attributed to the micro-cathodic effect of the V(CN) and Cr23C6 particles precipitated during aging. Although the best corrosion resistance in both H2SO4 and NaCl solutions was shown by the solution treated sample, 24 h-aged sample exhibited an improved corrosion resistance, ascribed to the improved chemical homogeneity of the austenite matrix due to long aging time (24 h).

The influence of aging treatment on shape memory effect (SME) and wear resistance of Fe–20Mn–5Si–10Cr–5Ni–0.7V–0.2N (mass%) alloy was investigated. Results showed that vanadium nitride (VN) particles precipitated during aging treatment, and the amount and size of the particles increased with increasing aging time. The sample aged for 8 h exhibited the maximal shape recovery ratio of 74% (compared with that of 16% for unaged) and favorable wear resistance in both dry wear and oil-lubricant wear conditions. The fine VN particles are the key factor to improve the SME by strengthening the alloy and acting as preferential nucleation sites for martensite. However, more and larger particles due to further aging treatment appeared to have negative effects on the SME and wear resistance. After oil-lubricant friction, there existed large amounts of friction-stress-induced ε martensite in the worn surface of the sample. As a result, the wear resistance of samples in oil-lubricant wear condition was remarkably higher than that in dry wear condition.

Error-prone repair of radiation-induced DNA double-strand breaks (DSBs) results in DNA mutation that is essential for mutation breeding. Non-homologous end joining might be the principal DSB repair mechanism in eukaryotes, which is mediated and activated by Ku protein, a heterodimer of 70 and 80 kDa subunits. In this study, on the basis of complementary DNA (cDNA), the genomic sequences of TaKu70 and TaKu80 genes in all the three genomes of wheat were characterized. Only single-nucleotide substitutions and no insertions or deletions were detected in the exons of TaKu70 and TaKu80 genes. The size of the introns exhibited a slight variation between the sequences. Yeast two-hybrid analysis demonstrated that TaKu70 and TaKu80 formed a heterodimer, and electrophoretic mobility shift assays revealed that this heterodimer bound to double-stranded DNA, but not to single-stranded DNA. The quantitative polymerase chain reaction analysis revealed that the expression of TaKu70 and TaKu80 genes was up-regulated under γ-ray irradiation in a dose-dependent manner in the seedlings of wheat. These results suggest that TaKu70 and TaKu80 form a functional heterodimer and are associated with the repair of the induced DSBs in wheat.