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The current study examined the relationship between napping duration and metabolic syndrome (MetS) among Chinese middle-aged and older adults over 4 years. We included 4,526 individuals aged ≥50 years who completed the 2011 and 2015 waves of the China Health and Retirement Longitudinal Study. General linear models were conducted to analyze the association of napping duration (none, 1 to 29 minutes, 30 to 59 minutes, 60 to 89 minutes, and ≥90 minutes) with MetS. At baseline, a higher prevalence of MetS was observed among participants with longer napping durations (60 to 89 minutes or ≥90 minutes) compared to non-nappers (odds ratio [OR] = 1.27, OR = 1.51, respectively). Among all participants, a napping duration ≥90 minutes at baseline was correlated with an increased risk of MetS 4 years later (OR = 1.58). Among participants without MetS at baseline, excessive napping (≥90 minutes) was predictive of a higher incidence of MetS 4 years later (OR = 1.46). Results revealed that excessive napping was related to an increased prevalence and incidence of MetS among Chinese middle-aged and older adults. [ Research in Gerontological Nursing, 16 (3), 115–124.]

The signal-to-noise ratio of infrared photodetectors can be improved by using resonant cavities, whereas the enhancement effect usually occurs in a narrow wavelength range. Here, we propose a dual-mode plasmonic resonant cavity which can enhance the performance of infrared photodetectors in a wide range of wavelengths from 3.5 $$\mu$$ m to 5.5 $$\mu$$ m. The optical cavity consists of an Au grating, an ultrathin (310 nm) detective layer of mercury cadmium telluride, and an Au film, which can exhibit nearly perfect absorption at resonant wavelengths with using optimal parameters. For wavelengths from 3.5 $$\mu$$ m to 5.5 $$\mu$$ m, the wavelength-averaged absorption in the detective layer can also be 62%, about 12 times of that without the resonant cavity. Such a high enhancement of absorption can occur for incident light in a broad range of angle ( $$\theta

Research on evacuation simulation and modeling is an important and urgent issue for emergency management. This paper presents an evacuation model based on cellular automata and social force to simulate the evacuation dynamics. Attractive force of target position, repulsive forces of individuals and obstacles, as well as congestion are considered in order to simulate the interaction among evacuees and the changing environment. A visual-guidance-based artificial bee colony algorithm is proposed to optimize the evacuation process. Each evacuee moves toward exits with the guidance of leading bee in his/her visual field. And leading bee is selected according to comprehensive factors including distance from the current individual, the number of obstacles and congestion, which avoids the randomness of roulette mechanism used by basic artificial bee colony algorithm. The experimental results indicate that the proposed model and algorithm can achieve effective performances for indoor evacuation problems with a large number of evacuees and obstacles, which accords with the actual evacuation situation.

During the Miocene, when the Zhujiang Formation was deposited, the eastern part of the Pearl River Mouth Basin, northern South China Sea, underwent intense mixed siliciclastic and carbonate sedimentation, particularly on the platform of the marginal ramp of the Dongsha Rise, northeastern margin of the South China Sea. Cores and well logs from industrial boreholes were collected and systematically investigated to reveal the sedimentary-petrographic characteristics of the mixed deposits and their formative processes. Four lithotypes were differentiated in the deposits, that is, (1) sandstone, (2) dolomitic sandstone and calcitic sandstone, (3) sandy dolomite and sandy limestone, and (4) dolomite, bioclastic limestone, and micrite limestone, which were formed by three major types of mixing processes: punctuated, facies, and in situ mixing processes. The porosity and permeability of the mixed deposits indicated that the siliciclastic component of the mixed deposits that experienced punctuated mixing formed the most high-quality hydrocarbon reservoirs. Exploration revealed that the lithologic reserves in the study area were mainly developed in mixed sedimentation areas. Our results suggest that the mixed sedimentation area, particularly with pure sandstone sedimentation or bioclastic sandstone, that underwent compaction or structural fracture activities, may be the next preference for lithologic exploration.

The Huizhou Movement refers to the Middle Eocene tectonic transition from the early to the late Wenchang Rifting stage (about 43 Ma ago) in the Pearl River Mouth Basin. Based on seismic reflection, drilling, logging and geological data, fault characteristic analysis, denudation thickness recovery, magmatism statistics, regional tectonic dynamics comparison and other methods are used to reveal the characteristics, properties and dynamic mechanism of the Huizhou Movement. The Huizhou Movement mainly shows the North-South transition of rifting and the migration along the faults, basement uplift, magmatic diapir and stratigraphic denudation. It is believed that the Huizhou Movement is a comprehensive reflection of plate interaction and lithospheric thinning process in the Pearl River Mouth Basin, which is closely related to the transition of lithosphere from initial rifting to rapid thinning, the India-Eurasia hard collision and the change of subduction direction of the Pacific plate. The Huizhou Movement has significant influence and control on the Paleogene hydrocarbon-generating sags and the development of hydrocarbon source rocks, sedimentary system and deep high-quality reservoir, hydrocarbon migration and accumulation in the Pearl River Mouth Basin.

The Z21 gas field is the only one gas field in the Huizhou depression. The distributions of sandstone and mudstone in the adjacent west zone control the extent of the Z21 gas field, making the confirmation of the reservoir connectivity between the west zone and main zone (RCWM) crucial. In this study, a practical workflow was proposed to confirm the RCWM. First, the sandstone and mudstone distributions were modeled by a sequential indicator simulation, using the vertical proportion curves as constraints. The porosity and permeability distributions were then predicted using a sequential Gaussian simulation based on sandstone and mudstone models. The sandstone, mudstone, and physical property models were treated as components of a geological embryonic model (GEM) prior to the RCWM confirmation. Different hypotheses on the RCWM of the GEMs were drawn, bringing variations to the GEMs and the GEMs turned to be different new models. These new models were then applied to numerical simulations, not only to perform quality checks, but also to attain the simulated formation pressure coefficients (Pfcs) and couple the study with the current formation pressure coefficients (Pfcc) derived from the modular formation dynamics tester (MDT). A hypothesis is negated if the Pfcs is not equal or approximately equal to the Pfcc. A coupled result was iteratively generated until the RCWM was confirmed. This coupling study on reservoir connectivity makes use of general geological reservoir models and highlights the ingenious designs based on different hypotheses of the RCWM to generate reliable results. Coupling study shows that distributions of formation pressure in the west zone of Z21 field are largely affected by a low-permeability belt and RCWM is proved weak due to the existence of the low-permeability belt.

The recent advent of acoustic metamaterials offers unprecedented opportunities for sound controlling in various occasions, whereas it remains a challenge to attain broadband high sound absorption and free air flow simultaneously. Here, we demonstrated, both theoretically and experimentally, that this problem can be overcome by using a bilayer ventilated labyrinthine metasurface. By altering the spacing between two constituent single-layer metasurfaces and adopting asymmetric losses in them, near-perfect (98.6%) absorption is achieved at resonant frequency for sound waves incident from the front. The relative bandwidth of absorption peak can be tuned in a wide range (from 12% to 80%) by adjusting the open area ratio of the structure. For sound waves from the back, the bilayer metasurface still serves as a sound barrier with low transmission. Our results present a strategy to realize high sound absorption and free air flow simultaneously, and could find applications in building acoustics and noise remediation.

Usually, materials with perfect structures possess excellent properties, but it is not always the case. Here, a new approach is reported to construct structural colored hydrogel films with excellent ultraviolet (UV) blocking performance for contact lenses. The theoretical simulation predicts that with perfect periodic structures, the hydrogel films can strongly reflect incident light in a narrow visible wavelength range and thus exhibit extraordinarily brilliant colors. However, such hydrogel films cannot effectively block UV light. By slightly breaking the structural periodicity (quasi-periodic structure), strong diffuse scattering or pseudoabsorption of light can occur for all of the wavelengths shorter than a structural characteristic length, leading to perfect UV blocking. According to the theoretical prediction, a structural colored hydrogel film with nearly periodic polystyrene sphere arrays in poly(hydroxyethyl methacrylate) hydrogel matrix is fabricated; this hydrogel film possesses brilliant colors and perfect UV blocking, and the core particle composition and size have been investigated in detail for the optimized properties of contact lenses. Meanwhile, the cell proliferation assay proves the cytocompatibility of the hydrogel for real application. Regarding its unique optical characteristics, the as-prepared structural colored hydrogel shows great promise in the fields of UV-protective equipment, medical device, soft robot, sensor, and so on.

In this paper, we investigate the structure of the Cenozoic rift basin in the proximal domain of the northern South China Sea (SCS) margin, with an emphasis on the influence exerted by pre-existing basement faults on rift development. Results of our work indicate that the overall rift architecture of the proximal domain of the northern SCS margin is associated with extensional faults arranged in two main structural trends, WNW- to EW- trending and ENE- trending. Structural evidence presented in this paper suggests that extensional faults of the two main structural trends mainly reactivated two pre-existing basement fault systems mapped in previous works, a WNW- to EW- striking thrust fault system (PFS1) and a ENE-striking thrust fault system (PFS2). During the first rifting phase, both pre-existing fault systems were reactivated; however, strains and depocenters were mainly localized on the ENE-striking normal fault system that reactivated the PFS2. On the contrary, in the second rifting phase, extension was mainly accommodated by WNW- to EW- striking normal faults that reactivated the PFS1, while most of the earlier ENE-striking normal faults became inactive or less active. These different degrees of reactivation of the two pre-existing fault systems during the two rifting phases suggest a clockwise rotation of the regional extension direction from NNW-SSE in the syn-rift stage 1 to N-S in the syn-rift stage 2. This study implies that apart from Cenozoic tectonic processes pre-existing structures have also played a key role during rifting evolution across the SCS margin.

Using a combined dataset including 3D seismic volumes, 2D profiles and 127 industrial wells, this study systematically investigated sequence stratigraphy and depositional architecture of the Pearl River Delta system (PRDS) during the Middle Miocene. In total, six stratigraphic sequences (SQ1 to SQ6) were recognized for the Hanjiang Formation, each of which could be further subdivided into a transgressive systems tract (TST) and a regressive systems tract (RST) according to a T-R sequence stratigraphic model. Seismic geomorphologic approaches were then conducted to interpret and map the key depositional elements, including fluvial channel systems, river mouth bars, longshore bars, shelf sand ridges and shelf sand sheets. After a detailed construction of the paleogeography for each of the twelves systems tracts, it was found that the types, geometries and depositional regimes of PRDS significantly altered at ca. 13.8 Ma. Before ca. 13.8 Ma, the PRDS were dominated by well-developed fluvial systems and an overall lobate shape, indicating a fluvial-dominated process. However, after 13.8 Ma, the whole PRDS began to form enormous shoreline-parallel depositional elements such as longshore bars, shelf sand ridges and shelf sand sheets, indicating dominant shore-parallel regimes. Besides, the whole deltaic system displayed obvious southwest deflection in map view after 13.8 Ma. Detailed analysis showed that this sudden change in the evolution of the PRDS could be ascribed to an interactive response to several factors. At ca. 13.8 Ma, the sea level began to rapidly rise and caused the fluvial energy to decrease, which was likely to lead to the diversion of the fluvial systems. Besides, the gradual uplift of the Dongsha Rise resulted in the raised shelf topography in the east region, thus confining the fluvial channels to flow southwestward. What's more, a few key paleoceanographic events, including the reglaciation of the Antarctic ice-sheet and the shoaling of the Pacific-Indian Ocean Seaway, might have contributed to the intensification of the southwesterly flowing paleocurrent along the northern South China Sea, thus triggering the delta asymmetry and deflecton of the PRDS after 13.8 Ma.

Seismic amplitude variation with offset (AVO) inversion is well-known as a popular and pragmatic tool used for the prediction of elastic parameters in the geosciences. Low frequencies missing from conventional seismic data are conventionally recovered from other geophysical information, such as well-log data, for estimating the absolute rock properties, which results in biased inversion results in cases of complex heterogeneous geologic targets or plays with sparse well-log data, such as marine or deep stratum. Broadband seismic data bring new opportunities to estimate the low-frequency components of the elastic parameters without well-log data. We have developed a novel AVO inversion approach with the Bayesian inference for broadband seismic data. The low-frequency components of the elastic parameters are initially estimated with the proposed broadband AVO inversion approach with the Bayesian inference in the complex frequency domain because seismic inversion in the complex frequency domain is helpful to recover the long-wavelength structures of the elastic models. Gaussian and Cauchy probability distribution density functions are used for the likelihood function and the prior information of model parameters, respectively. The maximum a posteriori probability solution is resolved to estimate the low-frequency components of the elastic parameters in the complex frequency domain. Furthermore, with those low-frequency components as initial models and constraints, the conventional AVO inversion method with the Bayesian inference in the time domain is further implemented to estimate the final absolute elastic parameters. Synthetic and field data examples demonstrate that the proposed AVO inversion in the complex frequency domain is able to predict the low-frequency components of elastic parameters well, and that those low-frequency components set a good foundation for the final estimation of the absolute elastic parameters.

To realize an ``acoustic laser'', enhanced emission of a source of plane waves of sound is important, but because such sources possess a large surface area and thus high reflection loss, amplifying emission is difficult. With this in mind, the authors design and fabricate a high-$Q$ acoustic surface that incorporates a sound-plane-wave source, and with appropriate structural parameters yields strongly enhanced emission. This work suggests an inventive method to create high-intensity collimated sound beams, which should see application in sound manipulation and nonlinear acoustics.

In order to quickly and efficiently simulate the crowd movement process under the evacuation scene, so as to reduce the casualties in emergency evacuation, this article proposes an indoor emergency evacuation model based on the improved artificial swarm algorithm. In this article, the cellular automata (CA) model is used to establish the evacuation environment, and then the artificial bee colony (ABC) algorithm is used to simulate the crowd evacuation. However, due to too many obstacles existing in the neighboring cells of some position, the individual in that position have to wait. If the distance equation is used to calculate the fitness, it may cause other individuals to choose these positions as new position and repeat the same mistake above. To reduce the occurrence of such cases, we improve the fitness function of the ABC algorithm. In the fitness function, the factors of attraction and repulsion force in social force model are introduced. And on the basis of the ABC algorithm, we propose the visual employed bee. The visual employed bee leads the onlooker bee to evacuate, so as to improve the efficiency of evacuation. The research results of this article can provide ideas for evacuation modeling and useful guidance for formulating evacuation strategies to reduce evacuation time and disaster losses.

Abnormal event detection, as a hot research field in intelligent video monitoring system, has attracted many researchers' attention in recent years. In order to overcome the shortcomings of the semi-supervised model, namely the training sample is difficult to contain all possible situations, leading to the occurrence of error detection, we propose a method based on support vector data description (SVDD). The principle of the method is to train the model with normal data and abnormal data respectively to obtain two SVDD models, and then judge whether there are abnormal events according to the results of the two models. This method has been tested by existing data sets and achieved good results.

Multiphase rifting with tectonic quiescence intervals is one of the most distinguishing features during the evolution of rift basins and rifted margins, which always produce oceanward rift migration. However, this law seems to be challenged in the proximal domain of the northern South China Sea (SCS) rifted margin. Based on high-quality 2D/3D seismic reflection data and borehole data from the Zhu 1 Depression located in the northern SCS, we examine the temporal and spatial variations of rifting. The regional unconformity, cyclicity of faulting, and rotation in extension direction indicate that the Zhu 1 Depression experienced continuous two-phase rifting with four stages but without distinct tectonic quiescence intervals. In Stage 1 of Syn-rift 1, rifts were distributed across the whole depression. They began to migrate towards the continent in stage 2 of Syn-rift 1, which continued until stage 1 of Syn-rift 2, and then migrated to the east. Rifting was also accompanied by a clockwise rotation of the strikes of fault systems, which were ~N065°E and ~N080°E in stage 1 and stage 2 of Syn-rift 1, respectively, and then rotated to ~ S085°E during Syn-rift 2. We suggest that the interactions between the pre-existing basement fabrics and the regional stress fields rotating clockwise can account for this rotation and the eastward rift migration. The rift migration towards the continent is supposed to be caused by the emplacement of the high-velocity lower crust (HVLC) underneath the Dongsha Uplift, which may initiate in the Eocene. The distinctive multidirectional, multiphase, and multi-mechanical rift migration reflects the uniqueness of the SCS rifted margin. This study helps us understand the complicated rifting process that interacts with pre-existing fabrics, regional stress field, and the emplacement of high-velocity lower crust.

The thin layer of infrared detection material guarantees the uniformity of the materials and reduces the signal noise in infrared detection. The absorption of infrared detector is limited by the thin layer of infrared detection material attributing to small volume. According to the characteristics of different infrared detection materials, artificial microstructure can effectively improve the performance of infrared detector. The strategies of enhancing the absorption of thin-layer infrared detection materials were introduced. The strategies were based on metal back plate, metal grating and asymmetric Fabry-Perot cavity. They could have an excellent performance in their own adaptive scenarios. Meanwhile, the mechanism of adjusting the absorption peak height and width by artificial microstructure was also elaborated briefly. The application of artificial microstructure in several infrared detectors was demonstrated. Finally, an artificial microstructure HgCdTe infrared detector was designed, which could achieve broadband absorption in 3.5-5.5 μm atmospheric window. The absorption peak reached 91.8% and the relative peak width was 41.8%. In most of frequency in the atmospheric window, the absorption enhancement is higher than 6. The development of artificial microstructure opens up the design idea of traditional infrared devices, and provides theoretical basis and guidance for new infrared devices.

When a charged particle moves parallel and close to the surface of a metasurface, intense Smith-Purcell radiation can be observed at resonant frequencies. Here, we present a systematic investigation on the Smith-Purcell radiation and evanescent-to-propagating wave conversion in metal-groove metasurfaces. Based on a coupled mode theory, analytic formulas are derived for the resonant frequency, Q-factor, and wave conversion efficiency at resonant frequency. The accuracy of the formulas is verified by numerical simulations. It is found that the resonant frequency and Q-factor depend on the depth and filling ratio of the grooves, respectively. A high Q-factor can be obtained by decreasing the filling ratio of the grooves. As the Q-factor increases, the wave conversion efficiency at resonant frequency increase but exhibits an upper limit. Such an upper bound of efficiency (Cr,max = 4) can be approached at a moderate Q-factor (Q = 16) or an optimal filling ratio of the grooves (fs = 0.05). Our results may benefit the construction of compact high-power free-electron light sources.

Emergent events and catastrophe accidents in large public places are increasing in recent years. In order to ensure successful escape from the accident places and provide a scientific and efficient plan for evacuees, an evacuation model based on artificial fish swarm algorithm(AFSA) for large public place is presented in this paper. In the model, each evacuee is considered as an intelligent artificial fish, and the foraging process of fish swarm is used to simulate evacuation behavior. Route choice strategy is proposed to simulate the psychological behaviors of evacuation individuals. Evacuation Simulation algorithm based on artificial fish swarm is proposed and applied to large stadium evacuation problem. The experimental and simulated results show that the presented model and algorithm can simulate the characteristics of the evacuation individuals, the evacuation rules and the uncertain factors in the evacuation process. The modelling approach has good effect in evacuation problem.

Aimed at four major issues in the oil and gas exploration of the southwestern Huizhou area in Pearl River Mouth Basin, in-depth study on geologic features and oil and gas reservoir forming pattern has been carried out to find out the exploration potential and direction of compound oil and gas reservoirs in this area. There develops the compound formation structure of basement, rifting and depression layers in this area, and a composite hydrocarbon transport system comprised by faults, sandstone layers and the sequence boundaries, which are connected to the several hydrocarbon generation subsags in the adjacent Huixi half graben. Controlled by the subsag-controlling boundary faults, long inherited paleo-uplifts and ancient structural ridges, oil and gas accumulate in multiple series in vertical direction, multiple connected traps horizontally, forming compound reservoirs of various traps. According to the three types of structural zones controlling oil and gas enrichment, the southwestern Huizhou area can be divided into seven compound oil and gas accumulation zones in three categories, which combine into a large compound hydrocarbon accumulation province. Key words: compound oil and gas accumulation play/zone, southwestern Huizhou area, Pearl River Mouth Basin, reservoir forming features, accumulation pattern, exploration potential

With the increase of emergencies in large public places, emergency evacuation research has become an important and urgent issue. This paper first proposes a tree hierarchical evacuation network. According to the hierarchical path selection strategy, the evacuation routes are obtained and sorted by the length of route. This hierarchical path selection strategy is more realistic than using the straight line distance. An evacuation model based on hierarchical directed evacuation network is presented in this paper, and a hierarchical directed artificial fish swarm algorithm is proposed to solve the evacuation problem. The model simulates the movements of pedestrians by means of preying, swarming, following and waiting behaviors of artificial fish swarm algorithm. During the evacuation process, the effects of congestion, retrograde and blocking time on evacuation speed and route selection are considered. The simulation results show that the proposed model and algorithm can effectively improve the evacuation efficiency in a stadium, and provide scientific and reasonable path guidance.

Few studies have focused their attentions on the source-to-sink (S2S) system from a multiple-level perspective. We have proposed an effective multilevel S2S subdivision approach based on the integrated study of seismic geomorphology, well-based facies, seismic facies and multi-attribute. The inspiration of multilevel S2S subdivision method is drawn mainly from the modern Diancang Mountain- Lake Erhai S2S system with different-orders of drainage divides. The Paleogene Central Uplift system during the syn-rift stage in Xijiang Sag, Pearl River Mouth Basin, South China Sea, provides a suitable example to test the approach and analyze the multilevel S2S characteristics of an ancient uplift system. The result shows that the Central Uplift system can be divided into three second-level sub-S2S systems (R-A, R-B and R-C), and can be further sub-divided into twelve third-level sub-S2S systems (A1∼A5, B1∼B5 and C1∼C2). Generally, the A1∼A5 and B1∼B4 systems are developed at the gentle slopes and deposited a series of narrow-shaped braided deltas with higher exploration potential, whereas the B5 and C1∼C2 systems are developed at the relatively steep slopes and deposited a series of lobate shaped turbidite and fan deltas with lower reservoir quality. Based on the multilevel S2S analysis, the ancient uplift can be scientifically sub-divided and compared with each sub-S2S system, including the sediment-transport type and distance, sedimentary facies characteristics and stacking relationship with the hydrocarbon source rocks. These in-depth and detailed studies have practical significance for the exploration of favorable reservoir sandbodies and stratigraphic-lithologic traps.

We demonstrate that when a charged particle moves on top of a metal-slot metasurface consisting of metallic slot resonators, strong Smith-Purcell electromagnetic (EM) radiation can be produced at resonant frequency. By adjusting the period of the metasurface, the resonant (or working) frequency can be tuned from gigahertz to terahertz and infrared regions. Since the EM field is localized in the slots rather than at the metal surface, the metasurfaces are found to exhibit a very low absorption loss ratio (1%) in low working frequencies (1 THz). Although it becomes larger in high frequencies (1 THz), the loss ratio remains relatively low (12%). In addition, a nonlinear relationship is also uncovered between the resonant frequency and the reciprocal of the period. Our results could benefit the construction of efficient, compact terahertz, and infrared free-electron light sources.