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The further development of fast electrochemical devices is hindered by self-discharge. Current strategies for suppressing self-discharge are mainly focused on the extrinsic and general mechanisms including faradaic reactions, charge redistribution, and ohmic leakage. However, the self-discharge process is still severe for conventional supercapacitors. Herein, we unravel the deterministic effect of solid-state diffusion energy barrier by constructing conjugately configured supercapacitors based on pairs of pre-lithiated niobium oxides with similar intercalation pseudocapacitive process but different phases. This device works with a single type of charge carrier while materials with various diffusion barriers can be implanted, thus serving as an ideal platform to illustrate the influence of the diffusion barrier. The results show that the comprehensive effect of solid-state diffusion energy barrier and extrinsic effects drives the self-discharge process. Noteworthy, the diffusion barrier presents with an exponential form, which governs the self-discharge of supercapacitors. This work is expected to unravel the deterministic effect of the solid-state diffusion energy barrier and provide a general guidance for suppressing self-discharge for supercapacitors., Comment: 35 pages, 16 figures, 1 table

In China, the orientation toward "ecological civilization" has been proposed for some years. But if the hard core of developmentalism and modernization continues to be the guiding principle, China will continue to be challenged by social injustice and environmental devastation.

Verbena officinalis Linn. is a kind of traditional Chinese medicine, which has a long history of application and shows good effects on neuroprotection. Therefore, we consider that V. officinalis may be a potential drug for treating Alzheimer’s disease (AD). First, ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) pointed out that the main chemical components in V. officinalis were iridoid glycosides, phenylethanoid glycosides, and flavonoids. These compounds were used for molecular docking and the results showed that these compounds had good anti-AD activity. To explore the biosynthetic pathway of anti-AD components in V. officinalis, UPLC and ultraviolet (UV) spectrophotometry were used for contents determination and the result was leaf > stem > root. At the same time, 92,867 unigenes were annotated in V. officinalis transcriptome; 206, 229, 115 related unigenes were, respectively, annotated in iridoid glycoside, phenylethanoid glycoside, and flavonoid pathway, of which 61, 73, and 35 were differential expression genes. The components had relatively high expression in leaves, which was consistent with the quantitative results. In addition, the tissue distribution particularity of verbenalin may be related to the branching of pathways. Meanwhile transcription factors VoWRKY6 and VoWRKY7 may be involved in the regulation of iridoid glycoside biosynthesis. Further, VoWRKY3, VoWRKY9, and VoWRKY12 may be related to flavonoid biosynthesis. The above research is helpful to explore the biosynthetic pathway of anti-AD components and the regulation mechanism of active components and to further explore the anti-AD effect of V. officinalis.

Beyond topical relevance, passage ranking for open-domain factoid question answering also requires a passage to contain an answer (answerability). While a few recent studies have incorporated some reading capability into a ranker to account for answerability, the ranker is still hindered by the noisy nature of the training data typically available in this area, which considers any passage containing an answer entity as a positive sample. However, the answer entity in a passage is not necessarily mentioned in relation with the given question. To address the problem, we propose an approach called \ttt{PReGAN} for Passage Reranking based on Generative Adversarial Neural networks, which incorporates a discriminator on answerability, in addition to a discriminator on topical relevance. The goal is to force the generator to rank higher a passage that is topically relevant and contains an answer. Experiments on five public datasets show that \ttt{PReGAN} can better rank appropriate passages, which in turn, boosts the effectiveness of QA systems, and outperforms the existing approaches without using external data.

A modified artificial bee colony algorithm is proposed for solving the scheduling optimization problem of multi-aisle automatic storage/retrieval system. The optimization model of the problem is analyzed and founded, in which the sequence constraint of tasks and calculation of the number of aisles are more realistic. According to the features of the problem, the encoding and decoding strategies for solutions to MABC algorithm are redesigned. Probability selection-based updating method is also introduced to enhance the neighborhood search and preserve the good fragments. The experimental results show that MABC can obtain better results than PSO and GA algorithm, and is a competitive approach for AS/RS scheduling optimization.

Zhoujiazhuang and the Puhan Rural Community offer contrasting experiences of how communities in different parts of China have responded to, negotiated, and undergone extensive changes during the last forty years since the reform policy was implemented in the country in 1979.

Additional file 1. Additional Tables S1–S10, Figures S1–S53.

Deep Q-learning algorithms often suffer from poor gradient estimations with an excessive variance, resulting in unstable training and poor sampling efficiency. Stochastic variance-reduced gradient methods such as SVRG have been applied to reduce the estimation variance (Zhao et al. 2019). However, due to the online instance generation nature of reinforcement learning, directly applying SVRG to deep Q-learning is facing the problem of the inaccurate estimation of the anchor points, which dramatically limits the potentials of SVRG. To address this issue and inspired by the recursive gradient variance reduction algorithm SARAH (Nguyen et al. 2017), this paper proposes to introduce the recursive framework for updating the stochastic gradient estimates in deep Q-learning, achieving a novel algorithm called SRG-DQN. Unlike the SVRG-based algorithms, SRG-DQN designs a recursive update of the stochastic gradient estimate. The parameter update is along an accumulated direction using the past stochastic gradient information, and therefore can get rid of the estimation of the full gradients as the anchors. Additionally, SRG-DQN involves the Adam process for further accelerating the training process. Theoretical analysis and the experimental results on well-known reinforcement learning tasks demonstrate the efficiency and effectiveness of the proposed SRG-DQN algorithm., 8 pages, 3 figures

Local scour can jeopardize the safety of the hydraulic structures and the ecology of a river system, so it is desirable to understand better the relevant processes and characteristics, and thus it is of primary importance for researchers to propose better research methodologies or numerical models. OpenFOAM is attractive for sediment-scour applications because of its high-quality hydrodynamic solvers and turbulence models, and its advantages of being open source and readily modifiable and extendable. However, the standard OpenFOAM package does not have a sediment scour module. It lacks the ability to perform large-amplitude motions needed for sediment-scour problems, and thus its application is normally restricted to small-amplitude cases to prevent divergence due to mesh deterioration. The first part of this study presents the implementation and validation of a new sediment-scour model with a strict vertex-based terrain conformal moving-mesh technique within the framework of OpenFOAM. The proposed simple moving-mesh technique in OpenFOAM is implemented to overcome the shortcomings of the conventional automatic mesh-motion techniques in handling large-amplitude moving geometries. The model is employed to simulate a simple case of prescribed boundary motion, a previous experiment in the literature, and a new laboratory experiment for local scour due to submerged wall jets. The results are compared with both the experimental and other numerical results. The comparisons demonstrate that the present model has the novel advantage of allowing for more severe topographic variations, and can provide more reliable predictions for the key characteristics and evolution of the bed profiles in wall jet scour problems. The second part of this study extends the model presented in the first part to simulate cases in which there is an embedded structure (here, a pipeline). In contrast to previous moving-mesh models, the newly implemented model uses masked elements to resolve the effects of the stationary object on the flow and sediment scour processes. This approach makes it possible to track directly the moving fluid-sediment interface using a very simple mesh setup, which is more practical for engineering computations than the existing models. The third part of this study further applies the proposed masked-element approach to simulate local scour at submerged weirs with downstream slopes. A new laboratory experiment is reported and used to validate the model. The effects of various parameters and configurations on the numerical predictions are studied, including the roughness height estimation, angle of repose, turbulence model, stochastic model, critical Shields number, and the form of the sand-slide model. The fourth part of this study provides some additional results and discussions, including the applications of the wall jet scour model, numerical modeling of flow around a pipeline near a scoured bed, and mesh configurations and improvement.

There is considerable interest in the history and characterization of China's economy. This overview of the evolution of the renminbi from the late Qing dynasty to the present, shows how China's political and economic changes in the twentieth and twenty-first centuries are reflected in the development of its highly contested modern currency system.

Throughout China's nearly seventy-year history of industrialization and financialization, whenever the cost of an economic crisis could be transferred to the rural sector, capital-intensive urban industries have had a "soft landing" and existing institutional arrangements have been maintained—a pattern that continues today. We argue that Chinese peasants and rural communities have rescued the country from no fewer than ten such economic crises.

The globalization led by financial capital has already resulted in ‘grain financialization’ (or grain dollarization), which is the most important factor giving rise to the grave situation in global food security, as well as turmoil in developing countries that rely heavily on grain imports.* This article analyzes food security issues in the twenty-first century in the context of international financial globalization. In particular, it pays attention to developing countries’ discontents and crises due to grain financialization, as well as China’s strategies in dealing with the dual risks existing in grain and financial markets.

Obstacle detection is very important for the autonomous movement of robots. Variety of sensors are used in obstacle detection to obtain information about obstacles. Different types of data obtained by sensors cannot be directly analyzed. This paper proposed an obstacle detection method based on heterogeneous data fusion. An image processing method is adopted to process the image of obstacle obtained by monocular vision sensor, and the size and position of the obstacle can be obtained. Then using infrared distance sensors are used to obtain distance of obstacles. Finally the location and distance information of obstacles can be obtained by a specific algorithm. Two experiments are performed for verifing the effect of proposed method. Experiments shown that the proposed method can effectively obtain the position and distance of obstacles.

Considering dangerous environmental conditions, maintenance of radioactive equipment can be performed by remote handling maintenance (RHM) system. The RHM system is a sophisticated man-machine system. Therefore, human factors analysis is an inevitable aspect considered in guaranteeing successful and safe task performance. This study proposes an approach for integrated analysis of human factors in RHM so as to make the evaluating process more practical. In the approach, indicators of accessibility, health safety, and fatigue are analyzed using virtual human simulation technologies. The human error factors in the maintenance process are analyzed using the human error probability (HEP) based on the success likelihood index method- (SLIM-) analytic hierarchy process (AHP). The psychological factors level of maintenance personnel is determined with an expert scoring. The human factors for the entire RHM system are then evaluated using the interval method. An application example is present, and the application results show that the approach can support the evaluation of the human factors in RHM.

The salinity distribution in an inverse estuary (where the sea water is concentrated by the estuary water) possesses its own uniqueness due to excessive net freshwater loss and restricted circulation. The study of long-term balance of salinity can contribute to a better understanding of the mixing and transport properties in such a distinct type of water body (i.e., inverse estuary water), and can provide valuable information for sound water management and environmental assessment. The Persian Gulf is chosen to be the study region, as it is a typical large-scale inverse estuary with severe shortages of freshwater resources and has been of significant research interest during the past several decades. For basin-wide examinations of a large-scale inverse estuary, analytical solutions are typically unavailable and field measurements are expensive, so numerical modeling as well as validation with available data is the main focus in this thesis. Firstly, the salinity distribution in the Persian Gulf is simulated with 8 different schemes, and the obtained results are compared with the World Ocean Atlas 2013 (WOA13) data. The comparisons can validate the utilization of the numerical model in predicting the salinity distribution in a large-scale inverse estuary. Given that results are affected by the choice of the numerical scheme, a performance analysis of candidate schemes is performed. The most appropriate scheme for the Persian Gulf is figured out in this stage. Secondly, the validated scheme is used for the prediction with respect to the long-term salinity response of the Persian Gulf to the climate change and anthropogenic activities. The results show that without mitigation measures taken, the salinity in the Persian Gulf will continually increase with time. The long-term and basin-wide simulations that will be presented in this thesis are expected to be more useful than previous studies (which were generally limited in time from hours to a few months) in terms of inspecting long-term characteristics. The performance of various numerical schemes has been assessed for the first time through a practical case study, which can contribute to a better understanding of the applications and characteristics of these schemes. Besides, the long-term salinity variations in the Persian Gulf are predicted for the next half-century, and this is the first numerical prediction of the long-term salinity response of the Persian Gulf to climate changes and anthropogenic activities.

A wide variety of enzymatic pathways that produce specialized metabolites in bacteria, fungi and plants are known to be encoded in biosynthetic gene clusters. Information about these clusters, pathways and metabolites is currently dispersed throughout the literature, making it difficult to exploit. To facilitate consistent and systematic deposition and retrieval of data on biosynthetic gene clusters, we propose the Minimum Information about a Biosynthetic Gene cluster (MIBiG) data standard.