The No.1 Central Document of 2024 emphasizes the need to learn from and apply the experience of the"Thousand-Village Demonstration,Ten-Thousand-Village Renovation"project to paint a new picture of livable,wo...The No.1 Central Document of 2024 emphasizes the need to learn from and apply the experience of the"Thousand-Village Demonstration,Ten-Thousand-Village Renovation"project to paint a new picture of livable,workable,harmonious,and beautiful villages,thereby accelerating agricultural and rural modernization and better advancing the construction of Chinese modernization.This paper,based on elucidating the scientific connotations and logical pathways of the"Thousand-Village Demonstration,Ten-Thousand-Village Renovation"project and"harmonious and beautiful villages",analyzes the practices of building"harmonious and beautiful villages"in Gansu Province.It proposes learning from the experience of coordinated advancement in the"Thousand-Village Demonstration,Ten-Thousand-Village Renovation"project to strengthen infrastructure and public service construction;learning from the experience of adapting to local conditions to reinforce rural industrial drive and integrated development;learning from the experience of environmental optimization and shaping to accelerate the improvement of human settlements and ecological civilization construction;and learning from the experience of co-construction,co-governance,and sharing to speed up rural governance and spiritual civilization development,thereby aiding the construction of harmonious and beautiful villages in Gansu.展开更多
This work established a quantitative method to access the shear stability of aerobic granular sludge(AGS)and validated its feasibility by using the mature AGS from a pilot-scale(50 tons/day)membrane bioreactor(MBR)for...This work established a quantitative method to access the shear stability of aerobic granular sludge(AGS)and validated its feasibility by using the mature AGS from a pilot-scale(50 tons/day)membrane bioreactor(MBR)for treating real municipal wastewater.The results showed that the changing rate( S)of the peak area(S)of granule size distribution(GSD)exhibited an exponential relationship(R^(2)≥0.76)with the shear time(y=a−b·c^(x)),which was a suitable indicative index to reflect the shear stability of different AGS samples.The limiting granule size(LGS)was defined and proposed to characterize the equilibrium size for AGS after being sheared for a period of time,whose value in terms of Dv50 showed high correlation(R^(2)=0.92)with the parameter a.The free Ca^(2+)(28.44-34.21 mg/L)in the influent specifically interacted with polysaccharides(PS)in the granule’s extracellular polymeric substance(EPS)as a nucleation site,thereby inducing the formation of Ca precipitation to enhance its Young’s modulus,while Ca^(2+) primarily interacted with PS in soluble metabolic product(SMP)during the initial granulation process.Furthermore,the Young’s modulus significantly affected the parameter a related to shear stability(R^(2)=0.99).Since the parameter a was more closely related(R^(2)=1.00)to S than that of the parameter b or c,the excellent correlation(R^(2)=0.99)between the parameter a and the wet density further verified the feasibility of this method.展开更多
Exploring the specific environmental impacts and mechanisms of China’s sustainable development pilot policy can enrich and expand China’s institutional and practical experiences,offering valuable insights and refere...Exploring the specific environmental impacts and mechanisms of China’s sustainable development pilot policy can enrich and expand China’s institutional and practical experiences,offering valuable insights and references for advancing global environmental sustainability.This study selects the National Innovation Demonstration Zone for Sustainable Development Agenda(NIDZSDA)as the sample and empirically evaluates the effects of the policy on urban environmental quality,using panel data from 74 prefecture-level cities in China between 2006 and 2020.The findings indicate that the sustainable development policy significantly improves urban environmental quality.Two key mechanisms identified are the aggregation of high-quality talent and the enhancement of technological innovation capabilities.Furthermore,the policy exhibits heterogeneous effects across different types of cities,with more pronounced improvements observed in mega and super cities,as well as in resource-based cities.展开更多
The increasing complexity of on-orbit tasks imposes great demands on the flexible operation of space robotic arms, prompting the development of space robots from single-arm manipulation to multi-arm collaboration. In ...The increasing complexity of on-orbit tasks imposes great demands on the flexible operation of space robotic arms, prompting the development of space robots from single-arm manipulation to multi-arm collaboration. In this paper, a combined approach of Learning from Demonstration (LfD) and Reinforcement Learning (RL) is proposed for space multi-arm collaborative skill learning. The combination effectively resolves the trade-off between learning efficiency and feasible solution in LfD, as well as the time-consuming pursuit of the optimal solution in RL. With the prior knowledge of LfD, space robotic arms can achieve efficient guided learning in high-dimensional state-action space. Specifically, an LfD approach with Probabilistic Movement Primitives (ProMP) is firstly utilized to encode and reproduce the demonstration actions, generating a distribution as the initialization of policy. Then in the RL stage, a Relative Entropy Policy Search (REPS) algorithm modified in continuous state-action space is employed for further policy improvement. More importantly, the learned behaviors can maintain and reflect the characteristics of demonstrations. In addition, a series of supplementary policy search mechanisms are designed to accelerate the exploration process. The effectiveness of the proposed method has been verified both theoretically and experimentally. Moreover, comparisons with state-of-the-art methods have confirmed the outperformance of the approach.展开更多
The energy contents of biogas could be significantly enhanced by upgrading it to vehicle fuel quality.A pilot-scale separation plant based on carbon hollow fiber membranes for upgrading biogas to vehicle fuel quality ...The energy contents of biogas could be significantly enhanced by upgrading it to vehicle fuel quality.A pilot-scale separation plant based on carbon hollow fiber membranes for upgrading biogas to vehicle fuel quality was constructed and operated at the biogas plant,Gl?r IKS,Lillehammer Norway.Vehicle fuel quality according to Swedish legislation was successfully achieved in a single stage separation process.The raw biogas from anaerobic digestion of food waste contained 64±3 mol%CH_4,30–35 mol%CO_2 and less than one percent of N_2 and a minor amount of other impurities.The raw biogas was available at 1.03 bar with a maximum flow rate of 60 Nm^3h^(à1).Pre-treatment of biogas was performed to remove bulk H_2O and H_2S contents up to the required limits in the vehicle fuel before entering to membrane system.The membrane separation plant was designed to process 60 Nm^3h^(à1)of raw biogas at pressure up to 21 bar.The initial tests were,however,performed for the feed flow rate of 10 Nm^3h^(à1)at 21 bar.The successful operation of the pilot plant separation was continuously run for 192 h(8days).The CH_4 purity of 96%and maximum CH_4 recovery of 98%was reached in a short-term test of 5 h.The permeate stream contained over20 mol%CH_4which could be used for the heating application.Aspen Hysys~?was integrated with Chem Brane(in-house developed membrane model)to run the simulations for estimation of membrane area and energy requirement of the pilot plant.Cost estimation was performed based on simulation data and later compared with actual field results.展开更多
With Xiangtian Village, Jin＇an County as an example, development objec- tive and functional orientation of ecological and leisure agricultural demonstration park were described in detail, based on which a characteris...With Xiangtian Village, Jin＇an County as an example, development objec- tive and functional orientation of ecological and leisure agricultural demonstration park were described in detail, based on which a characteristic and promising plan of the park was proposed.展开更多
Features of agritourism emerging in the development of modern agriculture were analyzed, it was stressed that industrial convergence was a basic feature of modern agriculture, and modern agriculture was the integratio...Features of agritourism emerging in the development of modern agriculture were analyzed, it was stressed that industrial convergence was a basic feature of modern agriculture, and modern agriculture was the integration of agriculture, science and technology, integration of agriculture, industry and trade, and integration of rural and urban areas. Agritourism was believed as the optimal carrier of expanding functions of modern agriculture combining agriculture, ecology and tourism industry. From such perspectives, causes for the loss of tourist functions in the development of agricultural demonstration zone were identified as 5 aspects, specifically including various planners from diverse fields; no any technical standard for the planning, or systematic planning theory and technique; many individual planning cases with poor applicability; no innovative idea brought into the tourism project planning; the loss of cultures in new tourist products. After proposing key points in the expansion planning of tourist functions, this research pointed out 4 countermeasures, i.e. (1) design concepts should be changed; (2) planning functions should be reoriented to match service facility planning with laws of tourism development and properly design tourist projects; (3) landscaping planning should be focused on; and (4) eco-environment protection and brand building should be enhanced.展开更多
In order to resolve the issue of soil erosion in East African plateau, a micro-landscape irrigation region was established in Ethiopia plateau to research status quo of agricultural demonstration site in Jari in Ethio...In order to resolve the issue of soil erosion in East African plateau, a micro-landscape irrigation region was established in Ethiopia plateau to research status quo of agricultural demonstration site in Jari in Ethiopia and to analyze the relation between structure and function of inner elements in different landscapes of demonstration site. Furthermore, in accordance with ecology, silviculture, agriculture and economics, the ecological landscapes were classified as per landscape functions; lands returning from farming were classified and re-used; ecosystems of grassland, river, agriculture and courtyard were researched; the feasibility of ecological restoration and sustainable development in demonstration site was demonstrated; the model for rational irrigation and water conservation was proposed. The research guarantees sustainable development of agriculture and animal husbandry and provides references for undeveloped countries with similar problems.展开更多
Popularization mode of government-dominated rural residential demonstration projects and its features were introduced.It was proposed that such a popularization mode still remained at the primary development stage and...Popularization mode of government-dominated rural residential demonstration projects and its features were introduced.It was proposed that such a popularization mode still remained at the primary development stage and was still suffering from many problems such as guiding role of government not fully played,lack of assessment standards,unitary funding channels,ineffective popularization effects and unpractical management regulations.In view of these problems,popularization strategies for rural residential demonstration projects were given from the perspective of establishing authorized coordination and supervision agencies,improving incentive policies of demonstration projects and also regulation system for these projects,expanding funding channels,and building information platforms.The study was to provide practical references for the future development of rural residential demonstration projects.展开更多
Environmental degradation and deforestation in Jari Demonstration Plot needed forestation and reforestation,and the plant species selection was a key issue in the ecological recovery.Ecological information was fully c...Environmental degradation and deforestation in Jari Demonstration Plot needed forestation and reforestation,and the plant species selection was a key issue in the ecological recovery.Ecological information was fully considered regarding each species in various agro-climatic zones,altitude ranges,specific niches in different landscapes,soil preference,drought resistance and certain other important ecological factors.The species selection model represents an idea of ecological recovery and soil erosion control in the demonstration plot.展开更多
From 2010 to 2012, the China Geological Survey Center for Hydrogeology and Environmental Geology Survey （CHEGS） carried out the project ＂Potential evaluation and demonstration project of CO2 Geological Storage in C...From 2010 to 2012, the China Geological Survey Center for Hydrogeology and Environmental Geology Survey （CHEGS） carried out the project ＂Potential evaluation and demonstration project of CO2 Geological Storage in China＂. During this project, we developed an evaluation index system and technical methods for the potential and suitability of CO2 geological storage based on China＇s geological conditions, and evaluated the potential and suitability of the primary basins for COz geological storage, in order to draw a series of regional scale maps （at a scale of 1：5000000） and develop an atlas of the main sedimentary basins in China. By using these tools, we delineated many potential targets for CO2 storage. We also built techniques and methods for site selection and the exploration and assessment of CO2 geological storage in deep saline aquifers. Furthermore, through cooperation with the China Shenhua Coal to Liquid and Chemical Co., Ltd., we successfully constructed the first coal-based demonstration project for CO2 geological storage in deep saline aquifers in the Yijinhuoluo Banner of Ordos in the Inner Mongolia Autonomous Region, which brought about the basic preliminary theories, techniques, and methods of geological CO2 storage in deep saline aquifers under China＇s geological conditions.展开更多
In solving the deterioration of biological treatment system treating petrochemical wastewater under low temperatures, bioaugmentation technology was adopted by delivering engineering bacteria into a pilot-scale two-st...In solving the deterioration of biological treatment system treating petrochemical wastewater under low temperatures, bioaugmentation technology was adopted by delivering engineering bacteria into a pilot-scale two-stage anoxic-oxic (A/O) process based on previous lab-scale study. Experimental results showed that when the concentrations of COD and NH4+-N of the influent were 370~910 mg/L and 10~70 mg/L, the corresponding average concentrations of those of effluent were about 80 mg/L and 8 mg/L respectively, which was better than the Level I criteria of the Integrated Wastewater Discharge Standard (GB8978-1996). According to GC-MS analysis of the effluents from both the wastewater treatment plant (WWTP) and the pilot system, there were 68 kinds of persistent organic pollutants in the WWTP effluent, while there were only 32 in that of the pilot system. In addition, the amount of the organics in the effluent of the pilot system reduced by almost 50% compared to that of the WWTP. As a whole, after bioaugmentation, the organic removal efficiency of the wastewater treatment system obviously in- creased.展开更多
The diffusion of e-commerce has played a significant role in recent rural economic development in China.E-commerce is also considered as an efficient channel to alleviate poverty in rural China.Voluminous studies have...The diffusion of e-commerce has played a significant role in recent rural economic development in China.E-commerce is also considered as an efficient channel to alleviate poverty in rural China.Voluminous studies have investigated the contribution of e-commerce to agricultural development,yet it is lacking empirical evidence as to the effects of e-commerce on rural poverty alleviation.Since the year of 2014,in order to develop rural e-commerce,Chinese government launched the National Rural E-commerce Comprehensive Demonstration Project.This gradual involvement policy offered a natural experiment for evaluation of e-commerce.Based on village-level survey data from rural China and Heckit method,our study finds that rural e-commerce has a significantly positive effect on rural income.Moreover,the effect is inverted U-shaped for the relative-poverty villages.The estimation of the propensity scores matching model confirms that the results are robust.The following policy recommendations are proposed:(1)policy support to rural e-commerce should prioritize the povertystricken villages.By doing so,the marginal income effects of e-commerce will be maximized.(2)Investment in internet infrastructure and establishment of human resources for e-commerce in rural areas will have spillover effects,increasing rural income through the"digital dividend".展开更多
We demonstrate a simple scheme of 6.835 GHz microwave source based on the sub-sampling phase lock loop(PLL). A dielectric resonant oscillator of 6.8 GHz is directly phase locked to an ultra-low phase noise 100 MHz ove...We demonstrate a simple scheme of 6.835 GHz microwave source based on the sub-sampling phase lock loop(PLL). A dielectric resonant oscillator of 6.8 GHz is directly phase locked to an ultra-low phase noise 100 MHz oven controlled crystal oscillator(OCXO) utilizing the sub-sampling PLL. Then the 6.8 GHz is mixed with 35 MHz from an direct digital synthesizer(DDS) which is also referenced to the 100 MHZ OCXO to generate the final6.835 GHz signal. Benefiting from the sub-sampling PLL, the processes of frequency multiplication, which are usually necessary in the development of a microwave source, are greatly simplified. The architecture of the microwave source is pretty simple. Correspondingly, its power consumption and cost are low. The absolute phase noises of the 6.835 GHz output signal are-47 d Bc/Hz,-77 dBc/Hz,-104 dBc/Hz and-121 dBc/Hz at1 Hz, 10 Hz, 100 Hz and 1 kHz offset frequencies, respectively. The frequency stability limited by the phase noise through the Dick effect is theoretically estimated to be better than 5.0 × 10^-14τ^1/2 when it is used as the local oscillator of the Rb atomic clocks. This low phase noise microwave source can also be used in other experiments of precision measurement physics.展开更多
Tertiary denitrification is an effective method for nitrogen removal from wastewater. A pilot-scale biofilter packed with suspended carriers was operated for tertiary denitrification with ethanol as the organic carbon...Tertiary denitrification is an effective method for nitrogen removal from wastewater. A pilot-scale biofilter packed with suspended carriers was operated for tertiary denitrification with ethanol as the organic carbon source. Long-term performance, biokinetics of denitrification and biofilm growth were evaluated under filtration velocities of 6, 10 and 14 m/hr. The pilot-scale biofilter removed nitrate from the secondary effluent effectively, and the nitrate nitrogen（NO_3-N） removal percentage was 82%, 78% and 55% at the filtration velocities of 6, 10 and 14 m/hr, respectively. At the filtration velocities of 6 and 10 m/hr, the nitrate removal loading rate increased with increasing influent nitrate loading rates, while at the filtration velocity of 14 m/hr, the removal loading rate and the influent loading rate were uncorrelated.During denitrification, the ratio of consumed chemical oxygen demand to removed NO_3-N was 3.99-4.52 mg/mg. Under the filtration velocities of 6, 10 and 14 m/hr, the maximum denitrification rate was 3.12, 4.86 and 4.42 g N/（m^2·day）, the half-saturation constant was 2.61, 1.05 and 1.17 mg/L, and the half-order coefficient was 0.22, 0.32 and 0.24（mg/L）1/2/min,respectively. The biofilm biomass increased with increasing filtration velocity and was 2845,5124 and 7324 mg VSS/m^2 at filtration velocities of 6, 10 and 14 m/hr, respectively. The highest biofilm density was 44 mg/cm^3 at the filtration velocity of 14 m/hr. Due to the low influent loading rate, biofilm biomass and thickness were lowest at the filtration velocity of 6 m/hr.展开更多
In this paper,an efficient skill learning framework is proposed for robotic insertion,based on one-shot demonstration and reinforcement learning.First,the robot action is composed of two parts:expert action and refine...In this paper,an efficient skill learning framework is proposed for robotic insertion,based on one-shot demonstration and reinforcement learning.First,the robot action is composed of two parts:expert action and refinement action.A force Jacobian matrix is calibrated with only one demonstration,based on which stable and safe expert action can be generated.The deep deterministic policy gradients(DDPG)method is employed to learn the refinement action,which aims to improve the assembly efficiency.Second,an episode-step exploration strategy is developed,which uses the expert action as a benchmark and adjusts the exploration intensity dynamically.A safety-efficiency reward function is designed for the compliant insertion.Third,to improve the adaptability with different components,a skill saving and selection mechanism is proposed.Several typical components are used to train the skill models.And the trained models and force Jacobian matrices are saved in a skill pool.Given a new component,the most appropriate model is selected from the skill pool according to the force Jacobian matrix and directly used to accomplish insertion tasks.Fourth,a simulation environment is established under the guidance of the force Jacobian matrix,which avoids tedious training process on real robotic systems.Simulation and experiments are conducted to validate the effectiveness of the proposed methods.展开更多
Under the guidance of strain tolerance, a new combination method for crude oil-degrading bacterial consortium was studied. Firstly, more than 50 efficient crude oil-degrading and biosurfactant producing bacteria were ...Under the guidance of strain tolerance, a new combination method for crude oil-degrading bacterial consortium was studied. Firstly, more than 50 efficient crude oil-degrading and biosurfactant producing bacteria were isolated from petroleum-contaminated soil and water in Tianjin Binhai New Area Oil field, China. Twenty-four of them were selected for further study. These strains were identified as belonging Pseudornonas aeruginosa, Bacillus subtilis, Brevibacillus brevis, Achrornobacter sp., Acinetobacter venetianus, Lysinibacillus rnacroides, Klebsiella oxytoca, Stenotrophornonas rhizophila, Rhodococcus sp. and Bacillus thuringiensis. A shake-flask degradation test revealed that 12 of these strains could degrade over 50% of 1% crude oil concentration in 7 d. Of these, 8 strains were able to produce biosurfactants. Furthermore, environmental tolerance experiments indicated that the majority of the strains had the ability to adapt to extreme environments including high temperatures, alkaline en- vironments and high salinity environments. A mixed bacterial agent comprising the strains WB2, W2, W3 and HA was developed based on the environmental tolerance tests and subjected to the pilot-scale degradation test indicating that this bacterial agent could degrade 85.2% of 0.8% crude oil concentration in 60 d. Our results suggest that the application of this mixed agent could remediate crude oil polluted soils in saline and alkaline environments.展开更多
On the basis of AHP method,this paper establishes comprehensive evaluation model of demonstration farmers' specialized cooperatives,uses the Delphi method and AHP software to assign scientific and objective weight...On the basis of AHP method,this paper establishes comprehensive evaluation model of demonstration farmers' specialized cooperatives,uses the Delphi method and AHP software to assign scientific and objective weight to 7 criteria in criteria layer and 27 indices in index layer,and evaluate the overall level of 153 farmers' specialized cooperatives whose main business is fruits and vegetables in Region R.The results show that the overall operation level of farmers' specialized cooperatives is common;democratic and financial management is open;the information-based level and social sensation are not insufficient;the marking results of questionnaire is basically scientific and objective.This paper discusses the new way to evaluate operation level of farmers' specialized cooperatives,and puts forward relevant countermeasures and suggestions as follows:promote the information-based level of demonstration cooperatives;strengthen the service capacity of demonstration cooperatives;use means of science and technology to promote product quality;amplify social sensation of farmers' specialized cooperatives.展开更多
After the United Nations Agenda 2030 was officially launched in September 2015,governments around the world have taken actions to implement the ambitious plan.This paper summarizes the actions and policies taken in Ch...After the United Nations Agenda 2030 was officially launched in September 2015,governments around the world have taken actions to implement the ambitious plan.This paper summarizes the actions and policies taken in China for promoting the implementation of the UN’2030 Agenda for Sustainable Development,with emphasis on promoting the development of demonstration zones for delivery of the Sustainable Development Goals(SDGs).The Chinese government has taken two types of measures.One is to formulate a series of national plans and strategies and the other is to construct pilot and demonstration zones.Two approaches were presented to optimize the selection criteria for demonstration zones:a problem-based approach;and a major function-based approach.Both provided priority regions and major themes for selection and construction of demonstration zones.Suggestions for promoting the development of demonstration zones include:(1)building a monitoring system for the implementation of SDGs in each demonstration zone and establishing an open online platform to track the progress;(2)forming an effective stakeholder participation mechanism.The experiences in constructing innovation-driven demonstration zones are insightful for other countries to take practical actions in the delivery of SDGs.展开更多
基金Supported by 2025 Gansu Provincial Party School(Institute of Administration)System Social Science Planning Project(QSDXYB2025046).
文摘The No.1 Central Document of 2024 emphasizes the need to learn from and apply the experience of the"Thousand-Village Demonstration,Ten-Thousand-Village Renovation"project to paint a new picture of livable,workable,harmonious,and beautiful villages,thereby accelerating agricultural and rural modernization and better advancing the construction of Chinese modernization.This paper,based on elucidating the scientific connotations and logical pathways of the"Thousand-Village Demonstration,Ten-Thousand-Village Renovation"project and"harmonious and beautiful villages",analyzes the practices of building"harmonious and beautiful villages"in Gansu Province.It proposes learning from the experience of coordinated advancement in the"Thousand-Village Demonstration,Ten-Thousand-Village Renovation"project to strengthen infrastructure and public service construction;learning from the experience of adapting to local conditions to reinforce rural industrial drive and integrated development;learning from the experience of environmental optimization and shaping to accelerate the improvement of human settlements and ecological civilization construction;and learning from the experience of co-construction,co-governance,and sharing to speed up rural governance and spiritual civilization development,thereby aiding the construction of harmonious and beautiful villages in Gansu.
基金supported by the Key Technologies Research and Development Program of Guangzhou (No.2023B03J1284)Guangdong Yuehai Water Investment Co.,Ltd. (No.CC80-QT01-2020-0010).
文摘This work established a quantitative method to access the shear stability of aerobic granular sludge(AGS)and validated its feasibility by using the mature AGS from a pilot-scale(50 tons/day)membrane bioreactor(MBR)for treating real municipal wastewater.The results showed that the changing rate( S)of the peak area(S)of granule size distribution(GSD)exhibited an exponential relationship(R^(2)≥0.76)with the shear time(y=a−b·c^(x)),which was a suitable indicative index to reflect the shear stability of different AGS samples.The limiting granule size(LGS)was defined and proposed to characterize the equilibrium size for AGS after being sheared for a period of time,whose value in terms of Dv50 showed high correlation(R^(2)=0.92)with the parameter a.The free Ca^(2+)(28.44-34.21 mg/L)in the influent specifically interacted with polysaccharides(PS)in the granule’s extracellular polymeric substance(EPS)as a nucleation site,thereby inducing the formation of Ca precipitation to enhance its Young’s modulus,while Ca^(2+) primarily interacted with PS in soluble metabolic product(SMP)during the initial granulation process.Furthermore,the Young’s modulus significantly affected the parameter a related to shear stability(R^(2)=0.99).Since the parameter a was more closely related(R^(2)=1.00)to S than that of the parameter b or c,the excellent correlation(R^(2)=0.99)between the parameter a and the wet density further verified the feasibility of this method.
基金fund support was received from National Social Science Fund of China[Grant No.23BJL010].
文摘Exploring the specific environmental impacts and mechanisms of China’s sustainable development pilot policy can enrich and expand China’s institutional and practical experiences,offering valuable insights and references for advancing global environmental sustainability.This study selects the National Innovation Demonstration Zone for Sustainable Development Agenda(NIDZSDA)as the sample and empirically evaluates the effects of the policy on urban environmental quality,using panel data from 74 prefecture-level cities in China between 2006 and 2020.The findings indicate that the sustainable development policy significantly improves urban environmental quality.Two key mechanisms identified are the aggregation of high-quality talent and the enhancement of technological innovation capabilities.Furthermore,the policy exhibits heterogeneous effects across different types of cities,with more pronounced improvements observed in mega and super cities,as well as in resource-based cities.
基金co-supported by the National Natural Science Foundation of China(No.12372045)the Guangdong Basic and Applied Basic Research Foundation,China(No.2023B1515120018)the Shenzhen Science and Technology Program,China(No.JCYJ20220818102207015).
文摘The increasing complexity of on-orbit tasks imposes great demands on the flexible operation of space robotic arms, prompting the development of space robots from single-arm manipulation to multi-arm collaboration. In this paper, a combined approach of Learning from Demonstration (LfD) and Reinforcement Learning (RL) is proposed for space multi-arm collaborative skill learning. The combination effectively resolves the trade-off between learning efficiency and feasible solution in LfD, as well as the time-consuming pursuit of the optimal solution in RL. With the prior knowledge of LfD, space robotic arms can achieve efficient guided learning in high-dimensional state-action space. Specifically, an LfD approach with Probabilistic Movement Primitives (ProMP) is firstly utilized to encode and reproduce the demonstration actions, generating a distribution as the initialization of policy. Then in the RL stage, a Relative Entropy Policy Search (REPS) algorithm modified in continuous state-action space is employed for further policy improvement. More importantly, the learned behaviors can maintain and reflect the characteristics of demonstrations. In addition, a series of supplementary policy search mechanisms are designed to accelerate the exploration process. The effectiveness of the proposed method has been verified both theoretically and experimentally. Moreover, comparisons with state-of-the-art methods have confirmed the outperformance of the approach.
文摘The energy contents of biogas could be significantly enhanced by upgrading it to vehicle fuel quality.A pilot-scale separation plant based on carbon hollow fiber membranes for upgrading biogas to vehicle fuel quality was constructed and operated at the biogas plant,Gl?r IKS,Lillehammer Norway.Vehicle fuel quality according to Swedish legislation was successfully achieved in a single stage separation process.The raw biogas from anaerobic digestion of food waste contained 64±3 mol%CH_4,30–35 mol%CO_2 and less than one percent of N_2 and a minor amount of other impurities.The raw biogas was available at 1.03 bar with a maximum flow rate of 60 Nm^3h^(à1).Pre-treatment of biogas was performed to remove bulk H_2O and H_2S contents up to the required limits in the vehicle fuel before entering to membrane system.The membrane separation plant was designed to process 60 Nm^3h^(à1)of raw biogas at pressure up to 21 bar.The initial tests were,however,performed for the feed flow rate of 10 Nm^3h^(à1)at 21 bar.The successful operation of the pilot plant separation was continuously run for 192 h(8days).The CH_4 purity of 96%and maximum CH_4 recovery of 98%was reached in a short-term test of 5 h.The permeate stream contained over20 mol%CH_4which could be used for the heating application.Aspen Hysys~?was integrated with Chem Brane(in-house developed membrane model)to run the simulations for estimation of membrane area and energy requirement of the pilot plant.Cost estimation was performed based on simulation data and later compared with actual field results.
文摘With Xiangtian Village, Jin＇an County as an example, development objec- tive and functional orientation of ecological and leisure agricultural demonstration park were described in detail, based on which a characteristic and promising plan of the park was proposed.
基金Supported by Hebei Provincial Natural Science Foundation (G2010000337)~~
文摘Features of agritourism emerging in the development of modern agriculture were analyzed, it was stressed that industrial convergence was a basic feature of modern agriculture, and modern agriculture was the integration of agriculture, science and technology, integration of agriculture, industry and trade, and integration of rural and urban areas. Agritourism was believed as the optimal carrier of expanding functions of modern agriculture combining agriculture, ecology and tourism industry. From such perspectives, causes for the loss of tourist functions in the development of agricultural demonstration zone were identified as 5 aspects, specifically including various planners from diverse fields; no any technical standard for the planning, or systematic planning theory and technique; many individual planning cases with poor applicability; no innovative idea brought into the tourism project planning; the loss of cultures in new tourist products. After proposing key points in the expansion planning of tourist functions, this research pointed out 4 countermeasures, i.e. (1) design concepts should be changed; (2) planning functions should be reoriented to match service facility planning with laws of tourism development and properly design tourist projects; (3) landscaping planning should be focused on; and (4) eco-environment protection and brand building should be enhanced.
基金Supported by South-South Cooperation Project of SSC/SPFS-FAO-Ethiopia-China~~
文摘In order to resolve the issue of soil erosion in East African plateau, a micro-landscape irrigation region was established in Ethiopia plateau to research status quo of agricultural demonstration site in Jari in Ethiopia and to analyze the relation between structure and function of inner elements in different landscapes of demonstration site. Furthermore, in accordance with ecology, silviculture, agriculture and economics, the ecological landscapes were classified as per landscape functions; lands returning from farming were classified and re-used; ecosystems of grassland, river, agriculture and courtyard were researched; the feasibility of ecological restoration and sustainable development in demonstration site was demonstrated; the model for rational irrigation and water conservation was proposed. The research guarantees sustainable development of agriculture and animal husbandry and provides references for undeveloped countries with similar problems.
基金Supported by Key Project of National Scientific and Technological Support Program(2008BAJ08B16)~~
文摘Popularization mode of government-dominated rural residential demonstration projects and its features were introduced.It was proposed that such a popularization mode still remained at the primary development stage and was still suffering from many problems such as guiding role of government not fully played,lack of assessment standards,unitary funding channels,ineffective popularization effects and unpractical management regulations.In view of these problems,popularization strategies for rural residential demonstration projects were given from the perspective of establishing authorized coordination and supervision agencies,improving incentive policies of demonstration projects and also regulation system for these projects,expanding funding channels,and building information platforms.The study was to provide practical references for the future development of rural residential demonstration projects.
基金Sponsored by FAO of the United Nations under South-south Cooperation Program in Ethiopia(SSC/SPFS-FAO-ETHIOPIA-CHINA)~~
文摘Environmental degradation and deforestation in Jari Demonstration Plot needed forestation and reforestation,and the plant species selection was a key issue in the ecological recovery.Ecological information was fully considered regarding each species in various agro-climatic zones,altitude ranges,specific niches in different landscapes,soil preference,drought resistance and certain other important ecological factors.The species selection model represents an idea of ecological recovery and soil erosion control in the demonstration plot.
文摘From 2010 to 2012, the China Geological Survey Center for Hydrogeology and Environmental Geology Survey （CHEGS） carried out the project ＂Potential evaluation and demonstration project of CO2 Geological Storage in China＂. During this project, we developed an evaluation index system and technical methods for the potential and suitability of CO2 geological storage based on China＇s geological conditions, and evaluated the potential and suitability of the primary basins for COz geological storage, in order to draw a series of regional scale maps （at a scale of 1：5000000） and develop an atlas of the main sedimentary basins in China. By using these tools, we delineated many potential targets for CO2 storage. We also built techniques and methods for site selection and the exploration and assessment of CO2 geological storage in deep saline aquifers. Furthermore, through cooperation with the China Shenhua Coal to Liquid and Chemical Co., Ltd., we successfully constructed the first coal-based demonstration project for CO2 geological storage in deep saline aquifers in the Yijinhuoluo Banner of Ordos in the Inner Mongolia Autonomous Region, which brought about the basic preliminary theories, techniques, and methods of geological CO2 storage in deep saline aquifers under China＇s geological conditions.
基金Project supported by the National Basic Research Program (973) of China (No. 2004CB418505)the Science and Technology Development Program of Heilongjiang Province (No. CC05S301), China
文摘In solving the deterioration of biological treatment system treating petrochemical wastewater under low temperatures, bioaugmentation technology was adopted by delivering engineering bacteria into a pilot-scale two-stage anoxic-oxic (A/O) process based on previous lab-scale study. Experimental results showed that when the concentrations of COD and NH4+-N of the influent were 370~910 mg/L and 10~70 mg/L, the corresponding average concentrations of those of effluent were about 80 mg/L and 8 mg/L respectively, which was better than the Level I criteria of the Integrated Wastewater Discharge Standard (GB8978-1996). According to GC-MS analysis of the effluents from both the wastewater treatment plant (WWTP) and the pilot system, there were 68 kinds of persistent organic pollutants in the WWTP effluent, while there were only 32 in that of the pilot system. In addition, the amount of the organics in the effluent of the pilot system reduced by almost 50% compared to that of the WWTP. As a whole, after bioaugmentation, the organic removal efficiency of the wastewater treatment system obviously in- creased.
基金financial support from the National Natural Science Foundation of China(71673274)the Outstanding Innovative Talents Cultivation Funded Programs 2019 of Renmin University of China。
文摘The diffusion of e-commerce has played a significant role in recent rural economic development in China.E-commerce is also considered as an efficient channel to alleviate poverty in rural China.Voluminous studies have investigated the contribution of e-commerce to agricultural development,yet it is lacking empirical evidence as to the effects of e-commerce on rural poverty alleviation.Since the year of 2014,in order to develop rural e-commerce,Chinese government launched the National Rural E-commerce Comprehensive Demonstration Project.This gradual involvement policy offered a natural experiment for evaluation of e-commerce.Based on village-level survey data from rural China and Heckit method,our study finds that rural e-commerce has a significantly positive effect on rural income.Moreover,the effect is inverted U-shaped for the relative-poverty villages.The estimation of the propensity scores matching model confirms that the results are robust.The following policy recommendations are proposed:(1)policy support to rural e-commerce should prioritize the povertystricken villages.By doing so,the marginal income effects of e-commerce will be maximized.(2)Investment in internet infrastructure and establishment of human resources for e-commerce in rural areas will have spillover effects,increasing rural income through the"digital dividend".
基金Supported by the National Key Research and Development Program of China under Grant No 2017YFA0304400the National Natural Science Foundation of China under Grant Nos 91336213,11703031,U1731132 and 11774108
文摘We demonstrate a simple scheme of 6.835 GHz microwave source based on the sub-sampling phase lock loop(PLL). A dielectric resonant oscillator of 6.8 GHz is directly phase locked to an ultra-low phase noise 100 MHz oven controlled crystal oscillator(OCXO) utilizing the sub-sampling PLL. Then the 6.8 GHz is mixed with 35 MHz from an direct digital synthesizer(DDS) which is also referenced to the 100 MHZ OCXO to generate the final6.835 GHz signal. Benefiting from the sub-sampling PLL, the processes of frequency multiplication, which are usually necessary in the development of a microwave source, are greatly simplified. The architecture of the microwave source is pretty simple. Correspondingly, its power consumption and cost are low. The absolute phase noises of the 6.835 GHz output signal are-47 d Bc/Hz,-77 dBc/Hz,-104 dBc/Hz and-121 dBc/Hz at1 Hz, 10 Hz, 100 Hz and 1 kHz offset frequencies, respectively. The frequency stability limited by the phase noise through the Dick effect is theoretically estimated to be better than 5.0 × 10^-14τ^1/2 when it is used as the local oscillator of the Rb atomic clocks. This low phase noise microwave source can also be used in other experiments of precision measurement physics.
基金supported by the Major Science and Technology Program for Water Pollution Control and Treatment of China (No. 2012ZX07302002)
文摘Tertiary denitrification is an effective method for nitrogen removal from wastewater. A pilot-scale biofilter packed with suspended carriers was operated for tertiary denitrification with ethanol as the organic carbon source. Long-term performance, biokinetics of denitrification and biofilm growth were evaluated under filtration velocities of 6, 10 and 14 m/hr. The pilot-scale biofilter removed nitrate from the secondary effluent effectively, and the nitrate nitrogen（NO_3-N） removal percentage was 82%, 78% and 55% at the filtration velocities of 6, 10 and 14 m/hr, respectively. At the filtration velocities of 6 and 10 m/hr, the nitrate removal loading rate increased with increasing influent nitrate loading rates, while at the filtration velocity of 14 m/hr, the removal loading rate and the influent loading rate were uncorrelated.During denitrification, the ratio of consumed chemical oxygen demand to removed NO_3-N was 3.99-4.52 mg/mg. Under the filtration velocities of 6, 10 and 14 m/hr, the maximum denitrification rate was 3.12, 4.86 and 4.42 g N/（m^2·day）, the half-saturation constant was 2.61, 1.05 and 1.17 mg/L, and the half-order coefficient was 0.22, 0.32 and 0.24（mg/L）1/2/min,respectively. The biofilm biomass increased with increasing filtration velocity and was 2845,5124 and 7324 mg VSS/m^2 at filtration velocities of 6, 10 and 14 m/hr, respectively. The highest biofilm density was 44 mg/cm^3 at the filtration velocity of 14 m/hr. Due to the low influent loading rate, biofilm biomass and thickness were lowest at the filtration velocity of 6 m/hr.
基金supported by National Key Research and Development Program of China(No.2018AAA0103005)National Natural Science Foundation of China(No.61873266)。
文摘In this paper,an efficient skill learning framework is proposed for robotic insertion,based on one-shot demonstration and reinforcement learning.First,the robot action is composed of two parts:expert action and refinement action.A force Jacobian matrix is calibrated with only one demonstration,based on which stable and safe expert action can be generated.The deep deterministic policy gradients(DDPG)method is employed to learn the refinement action,which aims to improve the assembly efficiency.Second,an episode-step exploration strategy is developed,which uses the expert action as a benchmark and adjusts the exploration intensity dynamically.A safety-efficiency reward function is designed for the compliant insertion.Third,to improve the adaptability with different components,a skill saving and selection mechanism is proposed.Several typical components are used to train the skill models.And the trained models and force Jacobian matrices are saved in a skill pool.Given a new component,the most appropriate model is selected from the skill pool according to the force Jacobian matrix and directly used to accomplish insertion tasks.Fourth,a simulation environment is established under the guidance of the force Jacobian matrix,which avoids tedious training process on real robotic systems.Simulation and experiments are conducted to validate the effectiveness of the proposed methods.
基金Supported by the National Basic Research Program of China(“973”Program:2014CB745100)the National Natural Science Foundation of China(21576197)+2 种基金Tianjin Research Program of Application Foundation and Advanced Technology(14JCQNJC06700)the Major Research Plan of Tianjin(16YFXTSF00460)Tianjin Penglai 19-3 Oil Spill Accident Compensation Project(19-3BC2014-03)
文摘Under the guidance of strain tolerance, a new combination method for crude oil-degrading bacterial consortium was studied. Firstly, more than 50 efficient crude oil-degrading and biosurfactant producing bacteria were isolated from petroleum-contaminated soil and water in Tianjin Binhai New Area Oil field, China. Twenty-four of them were selected for further study. These strains were identified as belonging Pseudornonas aeruginosa, Bacillus subtilis, Brevibacillus brevis, Achrornobacter sp., Acinetobacter venetianus, Lysinibacillus rnacroides, Klebsiella oxytoca, Stenotrophornonas rhizophila, Rhodococcus sp. and Bacillus thuringiensis. A shake-flask degradation test revealed that 12 of these strains could degrade over 50% of 1% crude oil concentration in 7 d. Of these, 8 strains were able to produce biosurfactants. Furthermore, environmental tolerance experiments indicated that the majority of the strains had the ability to adapt to extreme environments including high temperatures, alkaline en- vironments and high salinity environments. A mixed bacterial agent comprising the strains WB2, W2, W3 and HA was developed based on the environmental tolerance tests and subjected to the pilot-scale degradation test indicating that this bacterial agent could degrade 85.2% of 0.8% crude oil concentration in 60 d. Our results suggest that the application of this mixed agent could remediate crude oil polluted soils in saline and alkaline environments.
基金Supported by Ministry of Science and Technology Key Project of Science and Technology Support Program Blueprinted by the Tenth Five-Year Plan of China (2009BADB6B04)
文摘On the basis of AHP method,this paper establishes comprehensive evaluation model of demonstration farmers' specialized cooperatives,uses the Delphi method and AHP software to assign scientific and objective weight to 7 criteria in criteria layer and 27 indices in index layer,and evaluate the overall level of 153 farmers' specialized cooperatives whose main business is fruits and vegetables in Region R.The results show that the overall operation level of farmers' specialized cooperatives is common;democratic and financial management is open;the information-based level and social sensation are not insufficient;the marking results of questionnaire is basically scientific and objective.This paper discusses the new way to evaluate operation level of farmers' specialized cooperatives,and puts forward relevant countermeasures and suggestions as follows:promote the information-based level of demonstration cooperatives;strengthen the service capacity of demonstration cooperatives;use means of science and technology to promote product quality;amplify social sensation of farmers' specialized cooperatives.
基金supported by the National Key R&D Program of China(2019YFC0507505,2017YFC0505704)the National Natural Science Foundation of China(Grant No.71761147001).
文摘After the United Nations Agenda 2030 was officially launched in September 2015,governments around the world have taken actions to implement the ambitious plan.This paper summarizes the actions and policies taken in China for promoting the implementation of the UN’2030 Agenda for Sustainable Development,with emphasis on promoting the development of demonstration zones for delivery of the Sustainable Development Goals(SDGs).The Chinese government has taken two types of measures.One is to formulate a series of national plans and strategies and the other is to construct pilot and demonstration zones.Two approaches were presented to optimize the selection criteria for demonstration zones:a problem-based approach;and a major function-based approach.Both provided priority regions and major themes for selection and construction of demonstration zones.Suggestions for promoting the development of demonstration zones include:(1)building a monitoring system for the implementation of SDGs in each demonstration zone and establishing an open online platform to track the progress;(2)forming an effective stakeholder participation mechanism.The experiences in constructing innovation-driven demonstration zones are insightful for other countries to take practical actions in the delivery of SDGs.
