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A growing trend of aging population of China has brought tremendous pressure on the domestic care system, and community education is one of the important content for elderly services. Based on the framework of SAPAD, the community English class in Guangzhou City is taken for case study. Depth research on three stakeholeders-the elderly, social workers and volunteers are carried out by interview, user observation and field research. 6 levels (physical level, syntactic level, empirical level, semantic level, pragmatic level and social level) are extracted based on SAPAD framework, and the behavior- object-significance mapping is completed. Significant clusters of multiple users at different levels are analyzed, and 16 core significant clusters are jointly built. By linking with clustering results of the syntactic level, 6 new function modules are obtained. Finally, the community elderly education service system is built through personas, service blueprint, touch points and storyboard. The new service system will improve learning efficiency, satisfactions and emotional appeals for the elderly, and work efficiency of social workers and volunteers.
More people remain in the workforce into their late life as people’s life expectancy increases. This study examined the relationship between work stress and depressive symptoms of older workers in mainland China, focusing on the interplay between work stress with family and community factors in three (i.e., urban, rural, and migrant) settings.
National representative survey data on the Chinese labor force collected by the Social Science Research Center of Sun-Yetsen University in 2014 were used. The sample consisted of 5,751 workers aged 50 and above recruited from 29 out of 31 provinces in mainland China.
Work stress had a consistent and robust effect on depressive symptoms across older worker groups. Moreover, it interacted with family and community factors differentially in three settings. For migrant older workers, work stress was a dominant factor affecting their depressive symptoms. Among rural older workers, the influence of work stress on depressive symptoms depended on their family debt and neighborhood cohesion levels.
Stressors from work, family, and community comprised a general model that explains depressive symptoms in Chinese older workers. Interventions or service programs aimed at reducing work stress and improving mental health among older adults should consider the complexity of intertwining family and community dynamics as well as respective strengths in urban, rural, and migrant communities.
In order to reveal the quantitative relationship between fatigue crack deflection path and cross-sectional grain boundary (GB) arrangement of metallic nanolayered composites (NLCs), a stochastic model was established based on the interface-dominant fatigue damage for the ultrafine-scale NLCs. The model indicates that the crack deflection length decreases with decreasing GB arrangement deviation and grain size of constituent layers. The observation and quantitative analysis of fatigue cracking behavior of the Cu/W multilayers with a layer thickness of 5 and 20 nm was conducted to verify the model.
In January 2016, static GPS measurements were carried out in a 30 × 30 km2 area centered around Kunlun station at Dome Argus (Dome A), East Antarctica, to acquire high-precision 3-D geodetic coordinates at 49 sites. By comparing the coordinates with previous GPS measurements in 2008 and 2013 at the same sites, we constructed a detailed and long-term record of the ice-surface velocity field, 2008–2016, around Dome A. During this time span, the estimated ice-surface velocity ranges from 0.8 ± 0.3 to 28.7 ± 1.6 cm a−1, with a mean of 10.4 ± 0.3 cm a−1. From 2013 to 2016, the surface elevation of most Dome A areas exhibits a rising trend, and the maximum increase of snow surface elevation is 84.8 cm. The mean snow surface elevation change rate at Dome A is estimated to be 6.6 ± 0.7 cm a−1. The difference of 1.0 cm a−1 between the snow surface change rate derived from GPS and pole-height change rate from surface mass balance is suspected to be a result of a combination of firn densification and basal melt under Dome A.
A compact wideband out-of-phase power divider (PD) with improved isolation performance is proposed. This divider is formed by connecting an additional stub for isolation to output ports of a traditional Marchand balun with a defected ground structure (DGS) been used. To verify the design, a prototype divider is fabricated and tested. The measured results validate the 53.86% band-width centered at 3.43 GHz with more than 15 dB return loss at all ports, more than 17 dB isolation, respectively.
This paper is concerned with the travelling waves for a class of non-local dispersal non-cooperative system, which can model the prey-predator and disease-transmission mechanism. By the Schauder's fixed-point theorem, we first establish the existence of travelling waves connecting the semi-trivial equilibrium to non-trivial leftover concentrations, whose bounds are deduced from a precise analysis. Further, we characterize the minimal wave speed of travelling waves and obtain the non-existence of travelling waves with slow speed. Finally, we apply the general results to an epidemic model with bilinear incidence for its propagation dynamics.
A compact high-isolation power divider with bandpass response and high-frequency selectivity is presented in this letter. Two dual-mode resonators are used to realize filtering response. The circuit size of the proposed power divider can be reduced by using dual-mode capacitance loaded square meander loop resonators. Due to capacitive load, the resonator can exhibit slow-wave characteristics, which can be utilized to suppress harmonics and reduce size. The simulated and measured results show reasonable agreement.
This paper introduces recent activities on Marx-based compact repetitive pulsed power generators at the Institute of Applied Electronics (IAE), China Academy of Engineering Physics (CAEP), over the period 2010–2018. A characteristic feature of the generators described is the use of a simplified bipolar charged Marx circuit, in which the normal isolation resistors or inductors to ground are removed to make the circuit simpler. Several pulse-forming modules developed to generate a 100 ns square wave output are introduced, including thin-film dielectric lines of different structures, a pulse-forming line based on a Printed Circuit Board, and non-uniform pulse-forming networks. A compact repetitive three-electrode spark gap switch with low-jitter, high-voltage, and high-current was developed and is used in the generators. A positive and negative series resonant constant current power supply with high precision and high power is introduced. As an important part of the repetitive pulse power generator, a lower jitter pulse trigger source is introduced. Several typical high-power repetitive pulsed power generators developed at IAE are introduced including a 30 GW low-impedance Marx generator, a compact square-wave pulse generator based on Kapton-film dielectric Blumlein line, a 20 GW high pulse-energy repetitive PFN-Marx generator, and a coaxial Marx generator based on ceramic capacitors. The research of key technologies and their development status are discussed, which can provide a reference for the future development and application of miniaturization of compact and repetitive Marx generators.
Polydopamine (PDA) is a biopolymer, which can form uniform thin films on almost all solid substrates as well as at the liquid/air interface. Carbonized polydopamine possesses graphite-like structure and exhibits high electrical conductivity, which makes it a potential carbon-based thin film conductor. However, studies on mechanical behavior of PDA and its derived materials are very limited. In this study, PDA samples were synthesized through self-assembly of dopamine in aqueous solution. Elastic modulus of thin films was measured using the nanoindentation technique. It is shown that the Young’s modulus of PDA thin film increased with increasing heat treatment temperature (up to 600°C). Doping with Cu ions also increased the Young’s modulus of PDA. Furthermore, all PDA thin films, with and without Cu, exhibited creep behavior.
Highly dense zirconia dental ceramic coatings were fabricated by aqueous electrophoretic deposition (EPD) and subsequently sintered between 1250 and 1450 °C. Microstructural examination revealed that aqueous EPDZrO2 coatings possessed a tetragonal phase structure and the grain size increased with increasing sintering temperature. Nanoindentation study proved that the aqueous EPDZrO2 coating also had excellent mechanical properties. The effect of different applied loads on hardness and elastic modulus of the 1350 °C-sintered sample at room temperature was investigated by the method of progressive multicycle measurement nanoindentation. The simulative experiment proved that hardness of aqueous EPDZrO2 exhibited reverse indentation size effect (ISE) behavior and then displayed the normal ISE response. The analysis indicates that the reverse ISE is attributed to the relaxation of surface stresses resulting from indentation cracks at small loads and normal ISE is caused by geometrically necessary dislocations. The tetragonal–monoclinic stress-induced phase transformation during nanoindentation is the primary cause of dental zirconia failures.
Grain production potential (GrPP) is the maximum production in 1 year that can be achieved by land use under the limitations of climate conditions and in the absence of pests and diseases and other factors. Regional GrPP can change over time and there is an urgent need to identify the main factors affecting regional differences in such changes. Therefore, changes in GrPP were studied for six geographical units in Shaanxi Province, with summer maize and winter wheat as the main grain crops. Changes of GrPP during 2000–2015 were simulated by the global aro-ecological zone model. Analysis of modelled GrPP driven by observed changes in climate and land use suggest that over this period GrPP increased to the north but declined to the south of the Qinling Mountains. This is driven mainly by past changes in climate, with modelled GrPP more sensitive to changes in precipitation than temperature in all geographical units except one. Climate change was the main factor affecting GrPP in all geographical units except one; however, model prediction suggests that land use changes had a clear yield-reducing effect in three of the units. It is the conversion from cultivated land to construction land, grassland and woodland that led to the greatest declines in GrPP in these three geographical units. In order to ensure the stable development of regional agriculture and food security, Shaanxi Province should focus on tapping GrPP north of the Qinling Mountains and increasing the conversion rate of GrPP to actual production.
The interaction of stationary streaks undergoing non-modal growth with modally unstable instability waves in a high Mach number boundary-layer flow is studied using numerical computations. The geometry and flow conditions are selected to match a relevant trajectory location from the ascent phase of the HIFiRE-1 flight experiment; namely, a
half-angle, circular cone with
mm nose radius, free-stream Mach number equal to
, unit Reynolds number equal to
and wall-to-adiabatic temperature ratio of approximately
over most of the vehicle. This paper investigates the nonlinear evolution of initially linear optimal disturbances that evolve into finite-amplitude streaks, followed by an analysis of the modal instability characteristics of the perturbed, streaky boundary-layer flow. The investigation is performed with a stationary, full Navier–Stokes equations solver and the plane-marching parabolized stability equations (PSE), in conjunction with partial-differential-equation-based planar eigenvalue analysis. The overall effect of streaks is to reduce the peak amplification factors of instability waves, indicating a possible downstream shift in the onset of laminar–turbulent transition. The present study confirms previous findings that the mean-flow distortion of the nonlinear streak perturbation reduces the amplification rates of the Mack-mode instability. More importantly, however, the present results demonstrate that the spanwise varying component of the streak can produce a larger effect on the Mack-mode amplification. The analysis of planar and oblique Mack-mode waves modulated by the presence of the streaks shows that the planar Mack mode still dominates the instability characteristics of the flow. The study with selected azimuthal wavenumbers for the stationary streaks reveals that a wavenumber of approximately
times larger than the optimal wavenumber is more effective in stabilizing the planar Mack-mode instabilities. In the absence of unstable first-mode waves for the present cold-wall condition, transition onset is expected to be delayed until the peak streak amplitude increases to nearly 35 % of the free-stream velocity, when intrinsic instabilities of the boundary-layer streaks begin to dominate the transition process. For streak amplitudes below that limit a significant net stabilization is achieved, yielding a potential transition delay that can exceed 100 % of the length of the laminar region in the uncontrolled case.
A bulk NbCr2 Laves phase matrix composite toughened with ductile Cr phase has been fabricated by spark plasma sintering (SPS) using pre-alloyed NbCr2 and Cr powders. The sintering behaviour and phase morphological evolution of the sintered alloy were investigated. The results show that a series of microstructure evolutions along the sintering temperature occurred: elongated Cr phase with uniform dispersion of fine NbCr2 and Cr phase → coarse Cr phase with matured fine NbCr2 and Cr → coarse Cr and Nb phases with lamellar eutectics. The microstructural evolution and phase transformation along the sintering temperature are analyzed by considering the inhomogenous temperature distribution and the accelerated atomic diffusion due to the pulsed electric current applied during SPS. The room temperature fracture toughness of the sintered samples is expected to be markedly improved due to the absence of lamellar or the occurrence of ductile Cr and Nb phases.
The aims of this systematic review were to examine the effects of the overall and the different types of the interventions on the do-not-resuscitate (DNR) designation and the time between DNR and death among cancer patients.
Data were searched from the databases of PubMed, CINAHL, EMbase, Medline, and Cochrane Library through 2 November 2017. Studies were eligible for inclusion if they were (1) randomized control trails, quasi-experimental study, and retrospective observational studies and (2) used outcome indicators of DNR designation rates. The Effective Public Health Practice Project tool was used to assess the overall quality of the included studies.
The 14 studies with a total of 7,180 participants were included in this review. There were 78.6% (11 of 14) studies that indicated that the interventions could improve the DNR designation rates. Three types of DNR interventions were identified in this review: palliative care unit service, palliative consultation services, and patient-physician communication program. The significant increases of the time between DNR designation and death only occurred in a patient-physician communication program.
Significance of results:
The palliative care unit service provided a continuing care model to reduce unnecessary utilization of healthcare service. The palliative consultation service is a new care model to meet the needs of cancer patients in non-palliative care unit. The share decision-making communication program and physician's compassion attitudes facilitate to make DNR decision early. The individualized DNR program needs to be developed according to the needs of cancer patients.
Solving the problem of ship weather routing has been always a goal of nautical navigation research and has been investigated by many scientists. The operation schedule of an oceangoing ship can be influenced by wave or wind disturbances, which complicate route planning. In this paper, we present a real-coded genetic algorithm to determine the minimum voyage route time for point-to-point problems in a dynamic environment. A fitness assignment method based on an individual's position in the sorted population is presented, which greatly simplifies the calculation of fitness value. A hybrid mutation operator is proposed to enhance the search for the optimal solution and maintain population diversity. Multi-population techniques and an elite retention strategy are employed to increase population diversity and accelerate convergence rates. The effectiveness of the algorithm is demonstrated by numerical simulation experiments.
A method for extracting the substrate-independent stress–strain curves of thin films was developed using spherical nanoindentation to investigate the yield behavior of diamond-like carbon (DLC) thin films with Young’s moduli of ∼73 GPa and ∼76 GPa. The resulting stress–strain curves showed that these films commence yielding at ∼13 GPa and ∼14 GPa, respectively. These yield strength values agree with the critical pressure necessary to initiate the transformation of sp2-bonded carbon into significantly harder sp3-bonded carbon, indicating that the yielding of the materials is associated with the sp2-to-sp3 phase transition. The ability of a DLC film to accommodate a progressively increasing contact stress with strain beyond the yield point while dissipating part of the accumulated strain energy, as evidenced in this work, implies a unique mechanism of the brittle material for passively mitigating contact deformation and fracture in tribological applications.
Using repeat GPS measurements during 2005–16, we calculated and updated two-dimensional high-resolution decadal ice surface velocity estimates along the traverse route from Zhongshan Station to and around Dome Argus, East Antarctica. Along the 71 sites of the transect, the magnitudes of ice velocity increased from near 0 in Dome Argus to 1, 10 and ~100 m a−1 at the sites DT416, DT333 and LT980, respectively. The comparison between GPS and interferometric synthetic aperture radar (InSAR) derived results agree well when the magnitude of the ice surface velocities is faster than 5 m a−1, and disagree for slower flow velocities. A scale value 1.15 and 0.12 can be applied to InSAR derived results over this region with ice surface velocity larger and <5 m a−1, respectively. We attributed the cause of the discrepancy to the insensitivity of InSAR to the magnitude of low ice surface velocities, thus confirming the importance of GPS fieldwork-based ground truth high-resolution ice velocity estimates to constrain ice-sheet dynamics.
Grain production potential is mainly influenced by agroclimate and land use. In the present study, substantial regional differences associated with the impact of climate change were found (i.e. the degree of climate-related impacts varied among regions). Currently, there is an urgent need for effective responses and adaptations to different agricultural districts and agricultural production modes. Therefore, the aim was to examine ecotones and explore trends and influential factors associated with grain production potential change. Using the Global Agro-ecological Zone model, the grain production potential of West Jilin, China under different conditions during various years were estimated, considering meteorological, soil, topographic, land use and other data. The results showed that total grain production potential (TGrPP) of West Jilin increased continuously from 1976 to 2013. The average annual increase in TGrPP was higher in period 1 (1976–2000) than period 2 (2000–2013). In period 1, grain production potential was influenced mainly by irrigation percentage changes, followed by land use change. The conversion of grassland to farmland was the most important land use change factor that was associated with increased grain production potential. Climate change affected grain production potential in period 1 negatively. In period 2, climate change had the largest impact and land use imparted the smallest effect on grain production potential. Finally, the decrease in irrigation percentage resulted in reduced grain production potential.
The purpose of this study was to investigate the joint associations of dietary pattern and television viewing with risk factors of CVD among urban adults in China. A community-based cross-sectional study was conducted among urban adults in Nanjing, China. Five dietary patterns were identified based on a FFQ. Television time was obtained from a standard questionnaire and further classified into two categories (≤7, >7 h/week). Multiple logistic regression was used to calculate the OR and 95 % CI for the separate and joint associations of dietary patterns and television viewing with CVD risk factors. Compared with other dietary patterns, participants who followed the healthy traditional pattern had a lower likelihood of abdominal obesity (AO) (OR 0·52; 95 % CI 0·41, 0·67). Participants watching television no more than 7 h/week presented a 19 and 21 % lower likelihood for hypertension (HT) and elevated total cholesterol (ETC) than those with television time >7 h/week. Individuals who had less television time and a healthy dietary pattern had a lower OR for the presence of AO (OR 0·48; 95 % CI 0·36, 0·65), HT (OR 0·71; 95 % CI 0·66, 0·77), ETC (OR 0·72; 95 % CI 0·57, 0·91) and elevated TAG (OR 0·76; 95 % CI 0·61, 0·95), compared with those who followed other dietary patterns and television time >7 h/week. In conclusion, both healthy traditional pattern and less television time are jointly associated with reduced levels of CVD risk factors. It has important public health implications regarding the precision prevention of CVD at population level.
Congenital heart disease (CHD) is one of the most common birth defects. More than 200 susceptibility loci have been identified for CHDs, yet a large part of the genetic risk factors remain unexplained. Monozygotic (MZ) twins are thought to be completely genetically identical; however, discordant phenotypes have been found in MZ twins. Recent studies have demonstrated genetic differences between MZ twins. We aimed to test whether copy number variants (CNVs) and/or genetic mutation differences play a role in the etiology of CHDs by using single nucleotide polymorphism (SNP) genotyping arrays and whole exome sequencing of twin pairs discordant for CHDs. Our goal was to identify mutations present only in the affected twins, which could identify novel candidates for CHD susceptibility loci. We present a comprehensive analysis for the CNVs and genetic mutation results of the selected individuals but detected no consistent differences within the twin pairs. Our study confirms that chromosomal structure or genetic mutation differences do not seem to play a role in the MZ twins discordant for CHD.