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China, a country with a long-standing agricultural legacy, is increasingly prioritizing the reduction of CO2 emissions from its agricultural sector. Initially, the carbon emission sources within the agricultural sector are classified into two categories: direct and indirect emissions. Using this classification, the study calculates the generalized agricultural carbon emissions (GACEs) of 30 provinces in China between 2011 and 2020. To further understand the factors influencing GACEs, the paper employs the logarithmic mean Divisia index method and Tapio decoupling index to analyze seven key factors. These factors include carbon emission intensity, energy consumption of generalized agriculture, and economic benefit level of energy consumption. By comparing the impact and changes of GACEs during the 12th and 13th five-year plan periods, the study reveals valuable insights. The findings suggest that carbon emission intensity plays a crucial role in suppressing GACEs, while the level of economic development acts as a catalyst for their increase. By effectively managing these influencing factors, the paper proposes that the increase in GACEs can be effectively suppressed, and the achievement of agricultural CO2 reduction goals can be expedited. [ABSTRACT FROM AUTHOR]

A superconducting magnet with a warm-bore size of 800 mm and a center magnetic field of 9.4 T for the whole-body magnetic resonance imaging (MRI) system was developed in IEECAS, China. To achieve a highly homogeneous magnetic field over the 400 mm diameter of spherical volume (DSV), both active shimming and passive shimming techniques were employed. This paper mainly focuses on the implementation of passive shimming for the 9.4 T MRI magnet system. After four iterations, we were able to achieve peak-to-peak and root mean square field homogeneities over the DSV at 3.05 and 0.94 ppm, respectively. In addition, this paper analyzes the electromagnetic forces and system errors of passive shimming for ultra-high fields, providing valuable insights into MRI magnet engineering. [ABSTRACT FROM AUTHOR]

The high-quality development of new energy enterprises is of great significance to promote carbon peak and carbon neutrality and cope with the global warming crisis. However, with the increasing intensity of market competition and the appropriate weakening of the expected future subsidies, how to improve their performance through the fulfillment of the social responsibility of stakeholders has become a key scientific problem to be solved. Given the features of the new energy industry, including substantial initial investment, formidable technical barriers, and a pronounced reliance on policy support, this paper takes 182 new energy concept enterprises listed in China's A-shares in 2011–2020 as the research object. Employing qualitative comparative analysis, we extract four key rules for achieving high performance in new energy enterprises from the perspective of value co-creation of core stakeholders, including capital stakeholders (shareholders and creditors), technical stakeholders (employees), policy stakeholders (government and society), and upstream and downstream stakeholders (suppliers and customers). Then, we explore the performance improvement rules of typical cases. Our findings reveal that within the realm of new energy enterprises, capital-intensive enterprises with cost leadership and tax incentives, energy-manufacturing enterprises with suppliers dependence and saving environmental input, technology-innovation enterprises with cost leadership and talents dependence, and comprehensive-mature enterprises with suppliers dependence and tax incentives are more likely to achieve high performance. The findings can better guide management practice and promote the high-quality development of new energy enterprises. [ABSTRACT FROM AUTHOR]

With the increasing application of wind energy, reliable wind speed prediction has become imperative. However, prior studies predominantly concentrated on single-model predictions, disregarding the inherent uncertainty in wind speed. This oversight resulted in inadequate deterministic and probabilistic forecasting outcomes across varying scenarios. To make up for these shortcomings, a novel forecasting system combining a data preprocessing technique, a sub-model selection method, and a modified multi-objective integrate optimization strategy is designed in this paper. According to the data obtained from China's wind farm, the forecasting efficiency of this system is verified from multiple perspectives. The findings show that the system takes advantage of each model to boost the precision and stability of point prediction successfully. Furthermore, it achieves higher interval coverage and narrower interval width under distinct confidence levels. These results highlight the system's potential as a reliable technical support for efficient dispatching of the entire power system. [ABSTRACT FROM AUTHOR]

This paper proposes a high-performance receiver for underwater acoustic communications based on time reversal processing for multiple-input multiple-output (MIMO) systems. The receiver employs the vector approximate message passing (VAMP) algorithm as a soft equalizer in turbo equalization. By performing self-iteration between the inner soft slicer and the inner soft equalizer, the VAMP algorithm achieves near-optimal performance. Furthermore, an iterative channel-estimation-based soft successive interference cancellation method is incorporated to suppress co-channel interference in the MIMO system. Additionally, the introduction of passive time reversal technology can combine multiple channels into a single channel, which greatly reduces the computational complexity of the MIMO system, especially for large MIMO systems. The effectiveness of the proposed receiver is verified using experimental data collected in Songhua Lake, China in 2019. The results demonstrate that the proposed receiver significantly reduces the complexity of the traditional parallel-VAMP receiver without sacrificing performance and outperforms other receivers of the same type. Moreover, our experimental results also verify that the VAMP-turbo outperforms the generalized approximate message passing (GAMP)-turbo in terms of bit error rate and convergence performance. [ABSTRACT FROM AUTHOR]

The article discusses the highlights of the 2009 Conference on Advances in Microfluidics and Nanofluidics at the Hong Kong University of Science & Technology in Hong Kong, China on January 5-7. Among the supporters of the conference include the Institute for Advanced Study, the Institute of Complex Adaptive Matter and the Institute of Integrated Micro Systems. The conference consisted of sessions, contributed talks and poster presentations. Topics discussed include microfluidic science, nanofluidic science and microfludic and nanofluidic applications.

As a kind of renewable energy enterprise, wind power enterprise plays an important role in the energy transformation. However, its financing problems are also widespread. The purpose of this paper is to study the financing mode selection in order to improve sustainable development and future benefits of wind power enterprises. First, an evaluation index system is constructed through literature research and expert interviews, and the weight of each index is determined comprehensively by G1 and information entropy methods. On this basis, a financing mode selection model of wind power enterprises is constructed by using the prospect theory and hesitant fuzzy set. Next, this framework is used for case study. Financing patterns are ranked according to the comprehensive prospect value. The results show that financial leasing is the most suitable financing mode. Finally, the applicability and optimization of the model are proved by sensitivity analysis and comparative analysis. [ABSTRACT FROM AUTHOR]

The next-generation 650 MHz solid state power amplifier designed by the Institute of Modern Physics will utilize 24 modules with an output power of 60 kW. The outputs of each of the 12 modules will be combined using a 12-in-1 rectangular cavity combiner integrated into the rack. This cavity combiner, requiring only a single stage to combine power, is characterized by a minimal power loss and a high combining efficiency. The input couplers of the combiner are adjustable to change the number of combination channels. In the event of one amplifier module failure, the corresponding port can be adjusted to decouple, transforming the combiner to an (N-1)-channel combiner with a combining efficiency decay of 0.2%. The prototype of the combiner has been fabricated and tested with a small signal. The combining efficiency is 98.5%. In this paper, we will validate the feasibility of the combiner from the design, simulation, and experiment. [ABSTRACT FROM AUTHOR]

The Chinese national government and local governments have introduced multiple incentive measures to increase the market share of new energy vehicles (NEVs), such as dual credit policy, financial subsidies, and building new charging infrastructures. However, the government's budget to support the development of NEVs is limited. In this paper, we consider a duopolistic market consisting of a gasoline vehicle (GV) firm and an electric vehicle (EV) firm and develop a multi-level game-theoretic model based on the fact that the Chinese government seeks to achieve a given market share target with the minimum expenditure. A comparison of the equilibrium results in three incentive schemes differentiated by the financial subsidy is conducted to investigate the effectiveness of various incentive schemes. Furthermore, we consider a real situation in China that the government attempts to achieve a target for the total number of charging infrastructures through a reasonable policy design. The results in this study reveal that, with the EV market share target in mind, raising the requirements of dual credit policy has no effect on the EV firm's profit under EV purchase subsidy, is beneficial to the EV firm's profit under construction cost sharing subsidy, and is detrimental to the EV firm's profit under per-unit construction subsidy. It is worthwhile for the government to subsidize for infrastructure construction effort rather than consumers' purchase cost. Given a target for the total number of charging infrastructures, construction cost sharing subsidy can provide more motivation for the EV firm to build charging infrastructures than per-unit construction subsidy. [ABSTRACT FROM AUTHOR]

A scientific research device for geospace physics, the Space Plasma Environment Research Facility (SPERF), is going to be in operation this year at the Harbin Institute of Technology, China. One of its laboratory simulation platforms, the Asymmetric Reconnection EXperiment (AREX), is designed to investigate the asymmetric magnetic reconnection relevant to the process in the dayside magnetopause of the Earth. As a ground-based experimental platform, AREX emphasizes three-dimensional (3D) asymmetric driving features with topological similarity relevant to dayside reconnection. Thus, in this paper, we focus on topological analysis based on numerical simulation of AREX reconnection processes. 3D topological features in various scenarios relevant to magnetopause reconnection in different interplanetary magnetic field (IMF) conditions are investigated by adjusting setup parameters of plasma sources and magnetic coils. The simulation results reveal that the plasma distribution of asymmetric reconnection in SPERF-AREX is analogous to that at the magnetopause. Various types of the 3D magnetic topology relevant to typical IMF conditions, including the X-line and the A–B null chain structures, are, respectively, identified and analyzed in detail. [ABSTRACT FROM AUTHOR]

The China Spallation Neutron Source drift tube linac (DTL) is a high current intensity linear accelerator operated in pulsed mode. Beam loss is the most important cause of DTL performance degradation. Therefore, control of beam loss is very crucial to the linac's commission and routine operation. The beam loss in beam pulse width (∼several hundreds of microseconds) can be regarded as an instantaneous process, which may cause the local temperature of the drift tubes (DTs) to exceed the melting point or the thermal stress to exceed the material yield strength, resulting in permanent damage to the DTs. RF heating and beam loss are two major heat sources of the DTs during operation. First, temperature rise due to RF power dissipation is evaluated in this paper. Then, the thermomechanical response due to beam loss at different energies is investigated. It is found that the 3-MeV beam loss has the greatest stopping power and causes the largest temperature rise to the DTs. The maximum beam current loss for different working conditions is analyzed by both analytical method and ANSYS simulations, and the details will also be discussed in this paper. [ABSTRACT FROM AUTHOR]

The response potential of demand-side resources is becoming increasingly significant in integrated energy system (IES) operations. In addition, to ensure the effective participation of system devices, their actual responsiveness at different timescales should be considered. Based on these considerations, this paper proposes an IES multi-timescale operation optimization strategy that incorporates multiple forms of integrated demand response (IDR) and considers the response characteristics of the equipment. First, the multi-timescale characteristics of IDR are analyzed. Moreover, a multi-timescale operation model of IES that comprises day-ahead, intraday, and real-time stages is further established. In the day-ahead dispatch, a low-carbon economic scheduling model is developed by considering the shifting demand response (DR) and the cost of carbon emissions. In the intraday scheduling, noting that cooling and heat energy transmission possess slow dynamic characteristics, a rolling optimization model for cooling/heating coupled equipment considering load shedding and substituting DR is established. In real-time scheduling, the output of electric/gas coupled equipment is adjusted. Finally, an industrial park-type IES in northern China was selected as an example for a case study. The results show that (1) the IDR multi-timescale response strategy can exploit different types of demand-side flexibility resources. After implementing the shifting DR, the peak-to-valley difference of the electric load curve was reduced by 20%, and the total system cost was reduced by 2.3%. After implementing load shedding, the maximum load differences per unit period of the electric, heat, and cooling load curves decreased by 18.7%, 40.0%, and 68.9%, respectively. (2) By refining the timescale of IES optimization, the proposed model can effectively ensure the energy supply and demand balance of the system under different load scenarios and reduce the system operation cost. After applying the model to simulation in three typical days (transition season, summer, and winter), the penalty costs of lost loads reduce by ¥3650, ¥3807, and ¥3599, respectively, and the total system costs decrease by 17.4%, 16.1%, and 16.2%, respectively. [ABSTRACT FROM AUTHOR]

Urban road networks (URNs), as simplified views and important components of cities, have different structures, resulting in varying levels of transport efficiency, accessibility, resilience, and many socio-economic indicators. Thus, topological characteristics of URNs have received great attention in the literature, while existing studies have used various boundaries to extract URNs for analysis. This naturally leads to the question of whether topological patterns concluded using small-size boundaries keep consistent with those uncovered using commonly adopted administrative boundaries or daily travel range-based boundaries. This paper conducts a large-scale empirical analysis to reveal the boundary effects on 22 topological metrics of URNs across 363 cities in mainland China. Statistical results show that boundaries have negligible effects on the average node degree, edge density, orientation entropy of road segments, and the eccentricity for the shortest or fastest routes, while other metrics including the clustering coefficient, proportion of high-level road segments, and average edge length together with route-related metrics such as average angular deviation show significant differences between road networks extracted using different boundaries. In addition, the high-centrality components identified using varied boundaries show significant differences in terms of their locations, with only 21%–28% of high-centrality nodes overlapping between the road networks extracted using administrative and daily travel range-based boundaries. These findings provide useful insights to assist urban planning and better predict the influence of a road network structure on the movement of people and the flow of socio-economic activities, particularly in the context of rapid urbanization and the ever-increasing sprawl of road networks. [ABSTRACT FROM AUTHOR]

Electricity load forecasting is one of the important tasks of the power marketing department, and accurate load forecasting is extremely important to ensure real-time dispatch and security of the power system. In order to obtain accurate and reliable load forecasting results, an ultra-short-term power load forecasting model based on an improved random forest regression algorithm is proposed in this paper. First, data pre-processing is performed on the original dataset. Then the pre-processed time data and historical load data are used as inputs to the model, and optimization of the model using the Gaussian mixture-based tree-structured Parzen estimator algorithm is carried out. Finally, the final prediction results were derived. Experimental analysis was conducted with real load data from a region of China, and the experimental results show that the method has better prediction accuracy than the original random forest algorithm and other traditional machine learning algorithms. [ABSTRACT FROM AUTHOR]

A renewable portfolio standard is implemented to promote the development of renewable energy at a minimum cost through tradable green certificate market mechanism. Formulating a scientific and feasible renewable energy quota allocation scheme helps RPS function smoothly and optimize resource allocation. This paper proposed a bi-level programming model combined with entropy weight method to allocate renewable portfolio standard quotas with provincial heterogeneity and stakeholders' behavior, and an optimized quota allocation scheme among China's 30 provinces in 2020 was obtained. By comparing with the government's issued scheme, the following were the results under the optimized scheme: (1) Quotas in most provinces have increased, and the responsibility for renewable electricity generation is shared with the provinces with developed economy and well-constructed transmission facilities, where electricity producers can meet the quotas by purchasing tradable green certificate. (2) Quota allocation has positive effects on energy, economy, and environment. Specifically, the non-hydro renewable electricity generation increased by 43.8%, the non-hydro renewable electricity producers' profit increased by 18.4%, and the environmental pollution cost reduced by 27.9%. (3) Quota allocation equity measured by the environmental Gini coefficient increased by 14.3%. Based on these findings, some policy implications related to quota allocation and renewable portfolio standard's institutional arrangement have been put forward. [ABSTRACT FROM AUTHOR]

Distributed photovoltaic power generation can efficiently utilize idle resources and reduce carbon emissions. In order to reduce the impact of grid-connected distributed photovoltaic power fluctuations on grid operation, this paper simultaneously exploits the temporal dependence of power series and the spatial correlation of meteorological data to propose a combined prediction model with temporal characteristics and spatial relationships fused for distributed photovoltaic power plants with spatiotemporal information. First, in the study of time-dependent prediction, we propose a long and short-term memory neural network ensemble prediction model based on genetic algorithm-natural gradient boosting, which efficiently fits multiple sets of temporal characteristics of distributed photovoltaic. In the study of spatial correlation prediction, the meteorological data affecting photovoltaic power generation are selected by κ correlation coefficients, the target power plant and spatial reference power plant meteorological data are reconstructed into a two-dimensional matrix, and a two-dimensional convolutional neural network spatial feature extraction power prediction model is designed. Finally, the advantages of the two prediction models of temporal information and spatial features are fused by multiple error evaluation criteria improved information entropy, and a distributed photovoltaic power plant is constructed and implements highly accurate spatiotemporal information combination prediction model. The effect of the forecasting model in this study is validated using the photovoltaic cluster dataset in Hebei Province, China. Compared with other models, the results of this study show that the five prediction performance evaluation metrics of the proposed combined spatiotemporal information model are better. [ABSTRACT FROM AUTHOR]

Given the pillar role of renewable energy in the low-carbon energy transition and the balancing role of energy storage, many supporting policies have been promulgated worldwide to promote their development. To achieve the ambitious goal of no less than 1200 GW of wind and solar by 2030, China has also introduced policies to encourage the deployment of energy storage for the grid integration of renewable energy. The national policy is conducive to enhancing system flexibility for renewable integration, but it will also add the costs of renewable energy, especially when counting the regional differences. This paper adopts an improved levelized cost of electricity model to examine the total costs of renewable power co-deployed with energy storage in different provinces of China. The results show that the nationally unified energy storage co-deployment requirement, namely, 15% capacity ratio of renewable installation and 4 h duration, will negatively affect the economics of renewable generation, leading to an average cost increase in 15% and 21% for wind and photovoltaic generation, respectively. The economics of co-deploying energy storage under current market mechanism is inferior, but it can be effectively improved when energy storage participates in ancillary services market. With the revenue of frequency regulation, the cost of renewable co-deployed with energy storage can be even less than that without co-deployment in most provinces, except for Hebei, Jiangxi, and Gansu. An independent market entity status is thus conducive to encourage the co-deployment. Our finding also implies for a province-specific energy storage co-deployment policy. [ABSTRACT FROM AUTHOR]

In order to achieve sustainable development goals, China has further increased its goal of reducing carbon intensity and has made digitalization an important support for sustainable development. However, the impact of digitalization on carbon intensity reduction is still unclear. In this context, this paper first evaluates the digitalization level of 30 provincial regions in China and then constructs a spatial Durbin model for two stages, 2012–2015 and 2016–2019, so as to explore the spatial spillover effects of carbon intensity in different stages and the important roles of digital infrastructure and digital inputs in carbon intensity reduction. The main findings are as follows: (1) the current digitization level of each province in China is widely disparate, with the region showing a high level in the east and a low level in the west; (2) carbon intensity reduction has a significant spatial spillover effect, as shown by a 1% reduction in local carbon intensity and a 0.21% reduction in neighboring regions; and (3) digitalization has a more significant positive impact on the reduction in carbon intensity in stage 2. The research results are strong demonstration that digitalization drives sustainable development. [ABSTRACT FROM AUTHOR]

The magnetic reconnection process relevant to that at the magnetotail is one of the research contents of the Space Plasma Environment Research Facility, which is under construction at the Harbin Institute of Technology in China. Two magnetic mirror sub-coils placed symmetrically in the vertical direction and connected in series cooperate with a dipole coil to generate a magnetic field environment similar to the Earth's magnetotail. A capacitor-based pulsed power supply (PPS) system with a modular design is developed to excite two magnetic mirror sub-coils to generate a magnetic field with a magnetic flux density of not less than 200 G at the center of the two sub-coils. The PPS should deliver a pulsed current with a peak of more than 8 kA, and the duration of the current not be less than 95% of the peak over 5 ms to two magnetic mirror sub-coils when the charging voltage is not less than 20 kV. In addition, the duration from the peak to 10% of the peak is not more than 130 ms. The detailed design of the PPS is discussed in this paper, and a test method is designed to reduce the risk of damage to the wires and the connection between the wires and the coaxial cables of the PPS when the PPS discharges at a higher charging voltage. Finally, the discharge test of the PPS is carried out to verify the design of the PPS. [ABSTRACT FROM AUTHOR]

Short-term power load forecasting provides important guidance for the improvement of power marketing and control levels of power enterprises. In this paper, a novel method, named RF-TStacking, is proposed to forecast the short-term load. This study starts from the influence factors of the power load, the random forest is applied to estimate the importance of the influence factors of short-term load. Based on Stacking strategy, the integration of LightGBM and random forest is realized to achieve short-term power load forecasting. To improve the generalization ability of the load model, random put back sampling is used to sample each primary learner, and the average value is taken as the result of each primary learner. The Bayesian optimization is used to adjust the super parameters of the model to improve the accuracy of the selection of influencing factors. The load data of a region in northwest China are used for the testing, and it is found that the model can provide stable prediction results. [ABSTRACT FROM AUTHOR]

China's photovoltaic poverty alleviation power stations (PPAPS) properly combine poverty alleviation and renewable power generation while also meeting rural energy demands. The fundamental problem is how to optimize the benefits of PPAPS during its limited lifetime. Using the post-operation of photovoltaic poverty alleviation power plants as a starting point, this paper proposes a model combining real option theory and cooperative game to determine the ideal contract period of service committed by the government to the operation and maintenance (O&M) company, thus providing a reference for both parties. The model's validity and applicability are verified by incorporating a PPAPS from Henan Province in China as an example; ultimately, the factors influencing the O&M contract period are ranked using the Sobol global sensitivity analysis. The results show that when the solar industry's environment is positive, the government is more inclined to sign long-term contracts with O&M companies. In contrast, the more the government invests in the facilities, the more likely both parties will sign short-term contracts. Furthermore, the O&M company's capital investment in the power station has a direct impact on the contract period. Finally, corresponding policy recommendations are proposed for future O&M contracts. [ABSTRACT FROM AUTHOR]

Geological tectonic movement plays a controlling role in the distribution pattern of coalbed methane (CBM) resources. The traditional CBM resource estimation methods use the measured CBM as the overall CBM content and do not consider the influence of geological structure on the nonuniform distribution of CBM resources. In this paper, the geological structure of the Guojiahe coalfield in the northern Yonglong mining area, China, was used as the research background. Based on the precise three-dimensional (3D) seismic interpretation results of the coal seam geological structure and the tested CBM contents at sampling points, a fuzzy comprehensive evaluation method was used to classify the tectonic complexity of the study area, and the CBM contents of different tectonic locations in the tested coal seams and the results determined by the finite element method were analyzed. On this basis, a quantitative relationship between the tectonic complexity index and the amount of CBM resources was established, and finally, a CBM-enrichment prediction model and a CBM resource estimation method for areas with different tectonic complexities were proposed. The agreement between the amount of CBM resources obtained by the estimation method and the actual exploration result is 85.2%; therefore, the proposed method has a theoretical guidance and engineering application value for the exploration and precise development of CBM resources. [ABSTRACT FROM AUTHOR]

This paper takes the annular solar eclipse that occurred in China on June 21, 2020, as the background and conducts tests and analysis of shortwave timing sky wave signals. The test group continuously tested the signal field strength data from June 20, 2020, to June 23, 2020. The results show that the shortwave signal field strength on June 21, the day of the annular eclipse, is significantly weaker than that on two other days—before and during the annular eclipse—and there are three obvious jumps in the field strength value. (1) The first jump occurs more than one hour before the annular eclipse, and then, the field strength has an oscillatory attenuation. Between the first jump and the second jump, the overall change trend of the field strength value is an oscillatory decline one. (2) About 25 min before the beginning of the eclipse, the second jump of the field strength occurs; from the second jump to the third jump, that is, before the occurrence of the beginning of the eclipse and the transition phase from the beginning to the middle of the eclipse, the value of the field strength has an oscillatory increase. (3) During the period of 8:00–8:10, the field strength shows a third jump. Although the field strength oscillates after the third jump, it has no obvious increasing or decreasing trend. Based on the results of previous studies on the annular eclipse on that day and the analysis of the theoretical model of radio wave propagation, this paper preliminarily considers that the change in signal field strength is supposed to be caused by the impact of the outbreak of the annular eclipse on the ionosphere. When the annular eclipse occurred, the sunlight reaching the ground is blocked by the Moon, and the ionization degree of electrons in the ionosphere is reduced, resulting in an increase in the penetration factor, and the overall performance of the shortwave signal reaching the ground is weakened. [ABSTRACT FROM AUTHOR]

Battery storage is widely regarded as an indispensable solution to the large-scale integration of intermittent renewable energy into the power grid. Being still too expensive by itself, battery storage is currently promoted in China for utility-scale grid-parity wind/solar projects with compulsive technical standards or voluntary allocation requirements for those additional renewable projects beyond grid integration capacity. Under mandatory policies, part of the revenue from renewable energy is used to pay for battery storage. Without a mature electricity market, the development of battery storage co-located with renewable energy would be largely dependent on policy design. This paper conducts a policy-driven system dynamics simulation on the development mechanism of battery storage co-located with renewable energy in China. The results show that the installed capacity growth of battery storage will mainly be driven by mandatory policies before 2024 and mandatory policies will become almost ineffective after 2028. However, mandatory policies may still dominate the development of battery storage after 2030 if the cost reduction is restrained. The conclusions provide theoretical support for the development of battery storage co-located with renewable energy in China. To minimize the adverse effect of mandatory policy, policymakers should keep close eyes on the advance in technology and power market and adjust the policy accordingly. [ABSTRACT FROM AUTHOR]

To better address climate change and environmental pollution, it is of great practical significance to comprehensively evaluate the impact of low-carbon energy transition policies on carbon emission reduction. This paper conducts a policy quantitative evaluation of low-carbon energy transition policies from three dimensions: policy intensity, policy objective, and policy instrument. On this basis, the ridge regression model is used to analyze the carbon emission reduction effect of policies. The results show that (1) changes in policy quantities mainly cause the evolution of total policy effectiveness. The government's emphasis on low-carbon energy transition has fluctuated. (2) The two policy objectives of optimizing the use of fossil energy and developing a low-carbon concept are less synergistic with other policy objectives and neither has a significant impact on carbon reduction. (3) The government prefers to adopt command control policy instruments, but their actual carbon emission reduction effects are inferior to that of economic incentive policy instruments. These findings can provide a decision-making basis for the government to further formulate and optimize policies. [ABSTRACT FROM AUTHOR]

With the process of economic transformation and structural adjustment, low-carbon development has become an intrinsic and realistic demand for China's national economic and social development. This paper builds a system dynamic (SD) model of China's low-carbon development based on the internal influencing mechanisms of carbon sources, carbon flows, and carbon sinks, and then explores the impact of carbon sources, carbon flows, and carbon sinks system on carbon emissions under different scenarios. The model in our study is effective and practical, and it can not only clearly demonstrate the interaction mechanism between various systems but also provide effective policy recommendations for policymakers. The results show that (1) with the steady growth of the economy, China's total energy consumption and carbon emissions have increased significantly. By 2025, the total energy consumption will reach 628 798 ten thousand tons, and the carbon emissions will reach 689 257 ten thousand tons; (2) as for energy and industrial structure, on the one hand, energy restructuring is more effective in reducing carbon emissions than is industrial restructuring; (3) carbon sinks also play an important role in reducing greenhouse gas emissions. [ABSTRACT FROM AUTHOR]

3D asymmetric magnetic reconnection is an important investigation of the Space Plasma Environment Research Facility, which is being built as a user facility at the Harbin Institute of Technology in China. Four magnetosheath coils, which consist of Poloidal Field (labeled PF) coils and Toroidal Field (labeled TF) coils, are used to generate the magnetic field and plasma environment for the reconnecting experiment. A capacitor-based pulsed power supply (PPS) system with a modular design is developed to excite the magnetosheath coils to generate the required amplitude and duration of the magnetic field. The PPS system includes the PF PPS and TF PPS, which include four sets of PPSs, respectively. Each set of PF PPS and TF PPS consists of nine modules and four modules, respectively, and each module consists of a charge and discharge unit. The PF PPS can provide a pulsed current of no less than 360 kA for the corresponding PF coil at 0.11 ms when the charging voltage is 20 kV, and the duration of the pulsed current from the peak to 10% of the peak is no more than 0.6 ms. The TF PPS can provide a pulsed current of no less than 200 kA for the corresponding TF coil at 0.08 ms when the charging voltage is 20 kV, and the duration of the pulsed current from the peak to 10% of the peak is no more than 1.6 ms. The detailed design of the PPS has been discussed in this paper, and the detailed design of the main components in the discharge unit of the PPS is also given in this paper. Finally, the discharge tests of all the PPSs are carried out to verify the design of the PPSs, and the results of the PPSs in discharge tests indicate that all the PPSs meet the design requirements. [ABSTRACT FROM AUTHOR]

Hydrogen production from wind power and energy storage from wind power are considered as effective measures to overcome the problem associated with wind curtailment. However, their further development is clearly constrained by the incurred costs. Hydrogen production from offshore wind power (HPFW), hydrogen production from onshore wind power (HPNW), and underground pumped hydro energy storage from wind power (UPHESW) are considered in this paper. This paper employs a life cycle cost analysis to calculate and compare the levelized costs of hydrogen production and energy storage in China. A sensitivity analysis is conducted to evaluate the influences of different factors on levelized costs. The results show that the levelized cost of HPFW is 1.44 times that of HPNW. The levelized cost of UPHESW is lower than that of traditional pumped hydro energy storage with the same installed capacity and also lower than that of UPHESW with the smaller installed capacity. The economic competitiveness between UPHESW and HPNW depends on the installed capacity of UPHESW. If it exceeds 453 MW, UPHESW is more economical. If it remains below 453 MW, HPNW is more economical. [ABSTRACT FROM AUTHOR]

With the development of the economy and society, the problems of resources and the environment are becoming more and more prominent. As an environmentally friendly and clean energy, wind energy is developing rapidly with the support of relevant policies and technologies. At the same time, the development of the wind power industry is also faced with some problems, as the "abandoning wind" phenomenon of wind farms is still relatively common; the continuous decline of wind turbine prices and the sharp rise in operation and maintenance costs have further reduced the profit space of wind power manufacturers. The fundamental reason for the series of difficulties in the development of the wind power industry is the imbalance between the various links in the wind power industry chain. There is an urgent need to evaluate the performance of the wind power industry chain to improve the weak links. In this paper, by using the three-stage data envelopment analysis (DEA) model, the input-oriented BCC model is used in the first stage, and the stochastic Frontier analysis method is used to analyze the input relaxation variables in the second stage to eliminate two exogenous factors. In the third stage, the adjusted input variables are recalculated in the first stage, and the chain performance value of the wind power industry excluding environmental factors and random errors is obtained in the performance evaluation. This paper takes China's wind power industry as an example and makes an overall analysis of the upstream, middle, and downstream of the wind power industry chain from three aspects: technology performance, scale performance, and pure technology performance. The results show that under the support of policy and economy, the technical performance of the upper and lower reaches of China's wind power industry chain is higher, while the performance of the wind power industry chain is underestimated by environmental factors. The three-stage DEA model can eliminate the influence of environmental and random errors, which makes the evaluation of the wind power industry chain more objective. In addition, according to the evaluation results, the optimization direction of each structure of the industrial chain is put forward. [ABSTRACT FROM AUTHOR]

Solar irradiance data include temporal information and geospatial information, so solar irradiance prediction can be regarded as a spatiotemporal sequence prediction problem. However, at present, most of the research is based on time series prediction models, and the research studies on spatial-temporal series prediction models are relatively few. Therefore, it is necessary to integrate spatial-temporal information to construct a spatial-temporal sequence prediction model for research. In this paper, the spatial-temporal prediction model based on graph convolutional network (GCN) and long short-term memory network (LSTM) was established for short-term solar irradiance prediction. In this model, solar radiation observatories were modeled as undirected graphs, where each node corresponds to an observatory, and a GCN was used to capture spatial correlations between sites. For each node, temporal features were extracted by using a LSTM. In order to evaluate the prediction performance of this model, six solar radiation observatories located in the Xinjiang region of China were selected; together with widely used persistence model seasonal autoregressive integrated moving average and data-driven prediction models such as convolutional neural network, recurrent neural network, and LSTM, comparisons were made under different seasons and weather conditions. The experimental results show that the average root mean square error of the GCN-LSTM model at the six sites is 62.058 W / m 2 , which is reduced by 9.8%, 14.3%, 6.9%, and 3.3%, respectively, compared with other models; the average MAE is 25.376 W / m 2 , which is reduced by 27.7%, 26.5%, 20.1%, and 11%, respectively, compared with other models; the average R2 is 0.943, which is improved by 1.4%, 2.2%, 0.8%, and 0.4%, respectively, compared with other models. [ABSTRACT FROM AUTHOR]

The acoustics research at Tongji University began in the mid-1950s. The Institute of Acoustics (IOA) of Tongji University, which is one of the earliest institutions engaged in acoustics research in China, was formally established in 1984. The IOA has decades of experience in acoustics education, including offering a master's degree program for approximately 40 years, a Ph.D. program for 35 years, and a postgraduate program for 25 years. The IOA is one of the oldest acoustic research facilities in China with outstanding acoustics laboratories. Research at the IOA is performed in many areas of acoustics, which focus on detection acoustics and marine acoustics, laser ultrasonics and photoacoustics, medical ultrasonics and bioacoustics, architectural acoustics, environmental acoustics, noise control, functional and microstructural acoustic materials, aeroacoustics and aeronautical acoustics, and vehicle acoustics. This paper presents acoustics education at the undergraduate and graduate levels of Tongji University and its outstanding acoustics research facilities in detail. [ABSTRACT FROM AUTHOR]

The joint operation of large cascade hydropower plants changes the natural hydrological regime of the river, thereby reducing the stability of the basin ecosystem. To coordinate the power generation of cascade hydropower plants' demand and ecological environment demand, this paper establishes an ecological multi-objective optimized scheduling model (EMOOSM) for cascade hydropower plants, aiming at the maximum power generation of cascade hydropower plants and the minimum inappropriate ecological water volume. To solve the complex EMOOSM, a marine predators algorithm was introduced, which was improved and extended to the multi-objective solution level. Multi-objective improved marine predators algorithm (MOIMPA) based on Cauchy variation preserves non-dominated solutions by adding an external archive set and maintaining them with a crowdedness-based fast sorting strategy. The optimal dispatching results of a cascade hydropower plant in China's Pearl River system show that MOIMPA can effectively deal with conflicting power generation and ecological goals. The recommended scheme determined according to the fuzzy set theory and the principle of maximum satisfaction can adapt to the change law of ecological demand and reasonably adjust the inappropriate ecological water volume in the stage according to the different ecological sensitivity in the dispatching period. The recommended scheme in the normal year reduces the inappropriate ecological water volume caused by the operation of the cascade reservoir by 1.7156 × 105 m3 at the expense of only 1.12% of the power generation, effectively balancing the power generation and ecological benefits of the cascade hydropower plant operation. Compared with the results of other algorithms, the Pareto solution set obtained by MOIMPA has a better diversity metric (DM) indicator, maximum spread (MS) indicator, and hypervolume (HV) indicator. The research results provide a theoretical basis and reference for the ecological operation research of cascade hydropower plants. [ABSTRACT FROM AUTHOR]

The China Spallation Neutron Source project Phase-II aims to deliver 500 kW beam power to the spallation target. To meet the beam power requirement, an RF-driven negative hydrogen ion source with an external-antenna has been developed. In order to optimize the beam transmission through the radio frequency quadrupole and the downstream linac, the low energy beam transport line needs to be carefully studied and the transverse emittance is focused in this paper. With computational simulation and experimental verification, the emittance growth caused by nonlinear magnetic fields of the solenoid and the residual magnetic fields at the measuring position has been carefully analyzed. The measurement uncertainty of the double-slit scanner has also been quantitatively estimated. Using the same plasma-beam boundary setting, the beam extraction system is also optimized with particle tracking simulation in CST PARTICLE STUDIO. [ABSTRACT FROM AUTHOR]

The inaugural conference on Advances in Microfluidics and Nanofluidics was held at the Hong Kong University of Science and Technology on 5–7 January 2009 and brought together leading researchers from across a wide variety of disciplines from North America, Europe, Asia, and Oceania. This Special Topic section forms the second of the two issues dedicated to original contributions covering both fundamental physicochemical aspects of microfluidics and nanofluidics as well as their applications to the miniaturization of chemical and biological systems that were presented at the conference. [ABSTRACT FROM AUTHOR]

This paper selects China's renewable energy enterprises as a research sample and analyzes the impacts of equity balance and executive stock ownership on these companies' innovation efficiency from 2009 to 2018. The results show that equity balance has significant and positive impacts on innovation efficiency, while there is a significant nonlinear, inverted U-shaped relationship between the executive stock ownership and innovation efficiency. In addition, with changes in the shareholding ratio of the largest shareholder, equity balance and executive stock ownership are substitutive in terms of their impacts on innovation efficiency. Therefore, this paper proposes the following recommendations. The shareholding ratio of the largest shareholder should be controlled within a reasonable range to help force executives and outside blockholders to make decisions in the company's interests. When implementing an equity balance, companies should avoid shareholders' oversupervision of executives, which may restrict executives' enthusiasm for innovation investment. A moderate degree of freedom for management executives should be appropriate. [ABSTRACT FROM AUTHOR]

Highly precise and controllable liner implosions driven by a pulsed power facility have extensive applications in exploration of advanced hydrodynamics at the extremes of pressure and material velocity. In this paper, we describe a new pulsed power facility developed in China named FP-2 (a series of facilities for Fluid Physics investigations—the second generation) for liner implosions. Benefiting from the reliable and stable operation of 48 rail gap switches, the FP-2 facility can steadily transmit a current of 10.5 MA to a dummy load of 10 nH in the case of a charging voltage of ±40 kV. The first quarter cycle is 5.5 µs, and the percentage shot-to-shot deviation of the current history is less than 1%. When the aluminum liners of 60 mm in height and 0.6 mm in thickness are adopted, the maximum velocity of 4.5 and 7.5 km/s has been achieved with the liner diameter of 90 and 60 mm, respectively, at the diameter of 10 mm. Experimental results show that the percentage shot-to-shot deviation of the liner velocity history is less than 1%. As impact on the target, the maximum of the impact time deviation measured from four perpendicular fiber pins is less than 20 ns. Due to the modular design of FP-2, it is convenient for a future upgrade. The confirmation of high-quality implosion on FP-2, such as high repeatability, high reliability, and high symmetry, makes it a bright prospect to explore the advanced hydrodynamic problems at extremes of pressure and material velocity in the future. [ABSTRACT FROM AUTHOR]

This paper aims to investigate the influence of active cooling and natural cooling on the electrical performance of photovoltaic (PV) modules in a cold highland area in winter, and the thermal performance of two photovoltaic thermal (PV/T) systems for space heating. A comparative system with exactly the same size of a PV system, liquid-cooled PV/T system, and heat pipe PV/T system was designed and constructed in Ganzi city, China. The energy performance of these systems was tested under real weather conditions for several days. The experimental results show that the PV module can achieve the cooling effect by natural cooling, with a daily average temperature between 30 °C and 40 °C, and an electrical efficiency 3.71% higher than that of active cooling. However, the temperature of naturally cooled PV modules fluctuates drastically with time, and the temperature changes above 10 °C in a short time. The solar energy conversion efficiency of PV/T systems is more than 2.67 times that of a PV system. The heating power of the liquid-cooled PV/T system and heat pipe PV/T system can reach 847.4 and 948.5 W, and the primary-energy saving efficiency can reach 68.8% and 76.7%. A comparison of the intercept efficiency shows that the heat pipe PV/T system has the best energy performance. [ABSTRACT FROM AUTHOR]

As the installed capacity of renewable energy continues to increase, the proportion of China's renewable energy power generation has increased year by year, and carbon emissions have been effectively reduced. However, there is still a big gap between this and China's promised carbon emission reduction target. It is important to explore the coordination and optimization of power supply structure with the goal of carbon emission reduction. In the power market environment, there are conflicts of interest among wind power companies, thermal power companies, and energy storage equipment. Therefore, it is necessary to comprehensively consider their economic and environmental benefits to formulate subsidy policies. In order to solve the above problems, this paper studies the key issues of smart grid operation model, input-output efficiency, market game behavior, and policy effect simulation based on production simulation, game theory, statistics, and other theories. Finally, Matlab and Gridview were used to calculate the model results, and policy recommendations on wind power subsidies, thermal power carbon tax, and thermal power feed-in tariff were put forward. To achieve the goal of carbon emission reduction, renewable energy generation should be encouraged, and the proportion of installed capacity of wind and solar energy in the power structure should be increased. The most effective way is that the government should actively guide the subsidy mechanism into the electricity trading market. Based on the calculation results of the RTS-25 system in this article, the following policy recommendations can be put forward: within the government's financial capacity, at least 1 yuan per kilowatt-hour of wind power subsidy is provided, and the maximum of thermal power feed-in tariff is set at 0.7 yuan, and the higher the wind power subsidy and the lower the feed-in tariff of thermal power, the higher the carbon emission reduction. At the same time, a thermal power carbon tax of about 0.36 yuan per kilowatt-hour should be set. The results of this study can provide suggestions for consuming renewable energy and formulating competition rules in power market transactions. This article can be further studied. The scope of subsidy prices can be narrowed, and more precise subsidy prices that balance the benefits of various systems can be determined on the basis of this research. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new hydrodynamic model for gas–liquid two-phase flows in undulant pipelines based on the gas tracking method. The motion of three main forms of gas phase, including elongated bubbles, small bubbles, and gas pockets, is modeled by respective momentum equations. The mass transfer behaviors among the three gas forms, including interior mass transfer of single gas form, are considered. Therefore, the flow patterns along the pipeline can be predicted based on the gas tracking method. Afterward, the integrated pressure gradient of the gas–liquid two-phase flow in undulant pipelines can be obtained with the updated flow patterns. The model validation using the field data of a real pipeline in China shows that the accuracy of this model is within acceptable range. According to the simulation results, how the pipe terrain affects the gas transport and flow patterns is revealed, and sensitive analysis is carried out. These findings are of great practical value to obtain a deeper understanding of gas–liquid two-phase flows in undulant pipelines. [ABSTRACT FROM AUTHOR]

The mechanism of acceleration, loss, and wave–particle interaction of energetic particles in the magnetosphere is a research content of the Space Plasma Environment Research Facility, which is being built as a user facility at the Harbin Institute of Technology in China. Two magnetic perturbation coils are used to simulate the magnetic storm distortion and excite Alfvén wave perturbation. A capacitor-based pulsed power supply (PPS) system with a modular design is developed to excite the magnetic perturbation coils to generate the required amplitude and duration of the magnetic field. The two magnetic perturbation coils are the CRDI coil and CRDII coil and are excited by one set of PPSs. The PPS for the CRDI coil consists of two modules and can provide a pulsed current of no less than 132 kA at 0.12 ms when the charging voltage is 20 kV, and the duration of the pulsed current from the peak to 10% of the peak is no more than 0.7 ms. The PPS for the CRDII coil consists of five modules and can provide a pulsed current of no less than 16 kA at 0.45, 0.65, 0.8, 0.95, and 1.1 ms, and the duration of the pulsed current from the peak to 10% of the peak is no more than 4.5 ms. The detailed design of the PPSs has been discussed in this paper, and the discharge test of the PPSs is carried out to verify the design of the PPSs. [ABSTRACT FROM AUTHOR]

China's fast growing economy is inducing various technology dynamics. Much attention and resources are being paid to new energy technologies in China. These eight selected papers are a collection of academic studies on modeling and policy analysis of the diffusion of new energy technologies in China. These studies were all presented during the First International Workshop on 'Diffusion of New Energy Technologies in China,' held from 25-26 March 2011, in Shanghai, China. [ABSTRACT FROM AUTHOR]

This paper presents a single-carrier multiuser receiver in underwater acoustic communications with strong multiple access interference (MAI) combining passive time-reversal (PTR) and direct-adaptation-based turbo equalization. The receiver works in an iterative block by block manner. In the first iteration, when the symbols of all users are detected by successive interference cancellation (SIC) in the block, the channel impulse response (CIR) of each user is then updated by post-SIC signal to achieve more accurate MAI reconstruction and PTR combination for the next block. In the following iterations, the a priori mean of symbol in the current block is available and used to further improve the accuracy of reconstructed MAI and the updated CIR. The proposed receiver is demonstrated using experimental data collected at Songhua Lake, China, in 2019. The results show that single-carrier nine-user communication data with quadrature phase-shift keying can be successfully recovered, with an average data rate of 1.67 kbps for each user. [ABSTRACT FROM AUTHOR]

Clean energy has become one of the more broadly acceptable options for the future transformation of existing energy systems. The energy transformation also requires comprehensive preparatory actions. Organizing a multi-chain clean energy value chain into a complex clean energy network system is likely to be critical to the successful utilization of clean energy in the future. This article proposes a novel concept for a clean energy value co-creation system covering the entire clean energy value chain with division on power generation, energy storage, and end utilization sections. This article mainly analyzes the self-organizing evolution mechanism and value co-creation of the clean energy value co-creation system (CEVCS), which is therefore critical to the further development of the renewable energy industry. First, this article analyzes the connotation and basic structure of CEVCS and introduces the self-organizing characteristics of CEVCS. Second, the self-organizing evolution mechanism of CEVCS is discussed, which is analyzed from four aspects: evolutionary power, evolutionary path, evolutionary form, and evolutionary process. Third, this paper analyzes the information cooperative evolution process of CEVCS, defines the value order parameter, and studies how the constituent elements of CEVCS realize value creation through a synergy mechanism based on the theory of synergy. Then the dissipative structure model and information resource collaborative model of CEVCS are presented. Finally, the conclusions are given in the end. The proposed CEVCS concept would support the effective operation of the clean energy value chain within municipalities by establishing virtual energy cooperatives aimed at meeting energy needs and supporting community development. [ABSTRACT FROM AUTHOR]

As the Chinese government has promulgated many renewable energy generation policies to reduce carbon emissions and stimulate the renewable energy industry, it is vital to assess the policy effectiveness and extent to which they encourage sustainable renewable energy generation. This paper focused on the most prominent and the best-performing policy mechanisms feed-in tariffs (FIT) and renewable portfolio standards (RPS), and developed a system dynamics model to comprehensively evaluate the effectiveness and sustainability of the renewable energy generation policies. The model clearly shows the complex causal relationships between the related economic and environmental factors, and the policy scenarios were simulated to indicate the future trends and illustrate the coordination processes between polices and compare the development effects. The results show that current FIT has no obvious impact on the sustainable development of renewable energy industry, while under the integrated scenario, the RPS quota growth rate and fines have a significant positive effect after the construction period. The findings also suggest that a FIT-RPS integrated renewable energy generation policy and a perfect RPS trading system should be prioritized, and the RPS quota ratios and fines should be appropriately increased. As various policies cannot be simultaneously implemented because of financial and resource limitations, the proposed system of dynamics-based analysis approach is useful to analyze policy effectiveness and long-term industry sustainability to ensure the provision of optimized policies. It can also provide guidance for similar problems in different areas as well as decision support for further renewable energy generation policy development. [ABSTRACT FROM AUTHOR]

After the rapid development of China's wind power industry, the lack of core technology and the mismatch between the expansion and development speed have become increasingly prominent. In order to correctly understand the current situation and problems, the whole research process is divided into the following four steps. The first step takes the profit rate of main business from 2017 to 2019 as sample variable to study the smile pattern of the wind power industry value chain. The second step takes the Principal Component Analysis as the research method, and the evaluation index system is constructed, so as to further analyze the value-added driving factors. The third step uses the Data Envelopment Analysis (DEA) and Malmquist model as evaluation methods, and the static and dynamic efficiencies of each value chain link are evaluated, respectively. In step four, the selected companies are effectively clustered with the Cluster Analysis. The results show that the value chain shows a gradual deepening smile, the overall value-added efficiency is not ideal, and there are specific problems in each link. This paper aims to provide reference for enterprises to make targeted improvement on the basis of analyzing the current situation. It also provides reference for the comparison and promotion of other countries. [ABSTRACT FROM AUTHOR]

The Space Plasma Environment Research Facility currently under construction at the Harbin Institute of Technology in China uses four magnetosheath coils (flux cores) and a dipole coil to generate the magnetic field required for the study on the magnetopause magnetic reconnection. Two groups of magnetopause shape control coils (labeled CK coils) are used to slightly adjust the magnetic field distribution on the magnetopause. A capacitive pulsed power supply (PPS) system with a modular design is developed to excite CK coils. The PPS system consists of six sets of PPS with the same principle and structure, which are used to excite six sub-coils of the CK coils, respectively. Each set of PPS consists of ten modules and one local controller, and each module consists of a charger and discharge unit. Each set of PPS can provide a pulsed current of no less than 400 kA for the corresponding sub-coil at 0.11 ms when the charging voltage is 20 kV, and the duration of the pulsed current from the peak to 10% of the peak is no more than 0.6 ms. The detailed design of the PPS is discussed in this paper, and the discharge test of the PPS is carried out to verify the design of the PPS. Because there are acquisition and control devices in the discharge unit, the electromagnetic interference immunity design is also discussed to ensure the normal operation of the PPS. [ABSTRACT FROM AUTHOR]

African swine fever (ASF) is a highly contagious hemorrhagic viral disease of domestic and wild pigs. ASF has led to major economic losses and adverse impacts on livelihoods of stakeholders involved in the pork food system in many European and Asian countries. While the epidemiology of ASF virus (ASFV) is fairly well understood, there is neither any effective treatment nor vaccine. In this paper, we propose a novel method to model the spread of ASFV in China by integrating the data of pork import/export, transportation networks, and pork distribution centers. We first empirically analyze the overall spatiotemporal patterns of ASFV spread and conduct extensive experiments to evaluate the efficacy of a number of geographic distance measures. These empirical analyses of ASFV spread within China indicate that the first occurrence of ASFV has not been purely dependent on the geographical distance from existing infected regions. Instead, the pork supply–demand patterns have played an important role. Predictions based on a new distance measure achieve better performance in predicting ASFV spread among Chinese provinces and thus have the potential to enable the design of more effective control interventions. [ABSTRACT FROM AUTHOR]

A transportable fountain clock with high reliability is important for high-precision time-frequency measurements. Because of its relatively small cold atoms' collision frequency shift and ease of attaining high quantum state preparation efficiency, the rubidium atomic fountain clock has an indicated higher stability and reliability. This paper reports the design and operation of a transportable rubidium atomic fountain clock developed by the Shanghai Institute of Optical and Fine Mechanics, Chinese Academy of Science. After being transported more than 1000 km from Shanghai to the Changping Campus of the National Institute of Metrology, China, the optical platform and other hardware of the fountain clock did not need to be adjusted. The rubidium fountain clock maintained a stability of 4.0 × 10−13τ1/2, reaching 5.0 × 10−16 at 300 000 s. After transportation, the rubidium fountain clock and a cesium fountain clock (NIM5) were operated together against the reference frequency of a hydrogen maser. In three separate operating periods, over a total of nearly three months, the average frequency repeatability of the rubidium fountain was less than 3.8 × 10−15. [ABSTRACT FROM AUTHOR]

Foot-and-mouth disease is a highly contagious and economically devastating disease of cloven-hoofed animals. The historic occurrences of foot-and-mouth diseases led to huge economic losses and seriously threatened the livestock food security. In this paper, a novel age-space diffusive foot-and-mouth disease model with a Dirichlet boundary condition, coupling the virus-to-animals and animals-to-animals transmission routes, has been proposed. The basic reproduction number R 0 is defined as the spectral radius of a next generation operator K , which is calculated in an explicit form, and it serves as a vital value determining whether or not the disease persists. The existence of a unique trivial nonconstant steady state and at least one nonconstant endemic steady state of the system is established by a smart Lyapunov functional and the Kronoselskii fixed point theorem. An application to a foot-and-mouth outbreak in China is presented. The findings suggest that increasing the movements and disinfection of the environment for animals apparently reduce the risk of a foot-and-mouth infection. [ABSTRACT FROM AUTHOR]

In the study of indirect drive Inertial Confinement Fusion (ICF), X-ray images through the laser entrance hole of the hohlraums can provide key information. In this paper, we present the advances on the development of a gated X-ray imager with multiple views and spectral selectivity. A diagnostic snout which contains four X-ray planar mirrors has been designed and coupled to a gated X-ray detector which includes an air box and has a spatial resolution better than 35 µm and a temporal resolution better than 70 ps. The two inner mirrors in the diagnostic snout operate at M band (1.6–3.5 keV), while the two outer mirrors operate at N band (0.5–1 keV). The four mirrors define four observation angles. Each mirror can reflect 4 X-ray images to the four microstrips of the gated X-ray detector with almost the same observation angle. The imager enables us to observe the spatial and temporal evolution of plasma in the hohlraums from four different observation angles based on both N band and M band images. The imager has been used in the ICF experiments conducted at Shenguang laser facility in China, and the obtained X-ray images of Au cylindrical hohlraum are presented and discussed in this paper. [ABSTRACT FROM AUTHOR]