The standard material flow diagram in steel manufacturing process was proposed to analyze the influences of various material flows on environmental load of 1tof final product.Two influence factors and reducing measure...The standard material flow diagram in steel manufacturing process was proposed to analyze the influences of various material flows on environmental load of 1tof final product.Two influence factors and reducing measures of environmental load were pointed out.The environmental load was appraised for a typical technological process in a Chinese steel plant.展开更多
Understanding the underlying processes of how communities are structured remains a central question in community ecology. However, the mechanisms of the soil animal community are still unclear, especially for communit...Understanding the underlying processes of how communities are structured remains a central question in community ecology. However, the mechanisms of the soil animal community are still unclear, especially for communities on a small scale. To evaluate the relative roles of biotic interactions and environmental and spatial processes in a soil collembolan community, a field experiment was carried out on a small scale(50 m) in the farmland ecosystem of the Sanjiang Plain, Northeast China. In August and October, 2011, we took 100 samples each month in a 50 m × 50 m plot using a spatially delimited sampling design. Variation partitioning was used to quantify the relative contributions of the spatial and environmental variables. A null model was selected to test for the non-randomness pattern of species co-occurrence and body size in assemblages of collembolans and to test whether the pattern observed was the result of environmental or biotic processes that structured the community on a small scale. The results showed that large variance was accounted for by spatial variables(18.99% in August and 21.83% in October, both were significant). There were relatively lower effects of environmental variation(3.56% in August and 1.45% in October, neither was significant), while the soil water content, soil p H and soybean height explained a significant portion of the variance that was observed in the spatial pattern of the collembolan community. Furthermore, the null model revealed more co-occurrence than expected by chance, suggesting that collembolan communities had a non-random co-occurrence pattern in both August and October. Additionally, environmental niche overlap and the body size ratio of co-occurrence showed that interspecific competition was not influential in collembolan community structuring. Considering all of the results together, the contributions of spatial and environmental processes were stronger than biotic interactions in the small-scale structuring of a soil collembolan community.展开更多
In recent years, the beer industry is a biological food industry that consumes a lot of water, and it has developed rapidly in China. The sewage discharged from the mass production of beer poses a huge threat to the e...In recent years, the beer industry is a biological food industry that consumes a lot of water, and it has developed rapidly in China. The sewage discharged from the mass production of beer poses a huge threat to the environment. In order to evaluate and better solve the possible environmental impacts of beer treatment engineering projects, a brewery project in Foshan City is taken as an example to investigate the water pollution generation links of the engineering process including surface water and groundwater. According to the relevant technical methods and standards, water pollution factors are screened, and concentration and discharge are monitored. Through comprehensive analysis, predictive evaluation is obtained. It is confirmed that the project meets the requirements of national laws and regulations and environmental protection standards.展开更多
Green manufacturing is a mode to realize environmental friendliness by considering the environmental impact and energy consumption in manufacturing process.In order to make an environmental friendly assessment for man...Green manufacturing is a mode to realize environmental friendliness by considering the environmental impact and energy consumption in manufacturing process.In order to make an environmental friendly assessment for manufacturing process,a multi-criteria decision making( MCDM) model combined with fuzzy analytic hierarchy process( FAHP) and fuzzy technique for order preference by similarity to ideal solution( FTOPSIS) is proposed in this work.The environmental and resource criteria and manufacturing process objects are identified as the first step.Then,the weights of the criteria are calculated by FAHP.Finally,based on experts' evaluation using fuzzy words,the manufacturing process objects are ranked by FTOPSIS.The proposed methodology is applied to a gear shaft manufacturing.The sensitivity analysis and comparisons are implemented to prove its robustness and effectiveness for the ecofriendly assessment for process objects.展开更多
Soil environmental capacity is defined as the maximumpermitted load of the pollutant in a cettain soil environmental unitwithin a certain temporal period. With that load, the criteria canbe maintained, production and ...Soil environmental capacity is defined as the maximumpermitted load of the pollutant in a cettain soil environmental unitwithin a certain temporal period. With that load, the criteria canbe maintained, production and quality of crops can be gqaranteed.Regional soil capacity is the function of physical geographiccharacteristics. In determining capacity of sierozem, key stepsinclude: (1) establishing the criteria on comprehensive basis, (2)calculating the permitted input with the application of the capacitymodel. Dynamic capacity of Cd, Cu, As and Pb for sierozem isreported and compared with that of phaiozem and red 1oam.According to the results, it is obvious that regional differentiationin capacity is distinct and the distribution pattern of permittedload is closely related to the spacial variation of physicalgeographic processes.展开更多
In this paper,the development process of the construction of soil environmental quality standards in China is reviewed,and the construction situation of soil environmental quality standards in typical developed countr...In this paper,the development process of the construction of soil environmental quality standards in China is reviewed,and the construction situation of soil environmental quality standards in typical developed countries is introduced.According to characteristics of soil environment and practice of soil environment management in China,the relevant suggestions are discussed,thereby further perfecting construction work of soil environmental quality standards in China.展开更多
A methodology is presented to identify environmental impact minimization alternatives for reaction processes and assess their environmental performance. The potential environmental impact (PEI) scheme can be used to v...A methodology is presented to identify environmental impact minimization alternatives for reaction processes and assess their environmental performance. The potential environmental impact (PEI) scheme can be used to visibly display the transformation relationships among different types of PEI, identify the sources of environmental impacts, and propose alternatives for eliminating or minimizing the impacts. To evaluate the environmental performance of the alternatives effectively, some new indices, such as PEI input rate of non-products, PEI output rate of non-products per profit and the PEI conversion efficiency are proposed. Finally, the application of the methodology is illustrated using an industrial case study.展开更多
The meteorological big data in Beijing area are typical multi-dimensional big data containing spatiotemporal characteristics,which have important research value for researches related to urban human settlement environ...The meteorological big data in Beijing area are typical multi-dimensional big data containing spatiotemporal characteristics,which have important research value for researches related to urban human settlement environment.With the help of computer programming and software processing,big data crawling,integration,extraction and multi-dimensional information fusion can be realized quickly and effectively,so as to obtain the data set needed for research and realize the target of visualization.Through big data analysis of wind environment,thermal environment and total atmospheric suspended particulate pollutants in Beijing area,it was found that the average wind speed in Beijing area decreased signifi cantly in recent 40 years,while the surface temperature increased signifi cantly;urban heat island effect was signifi cant,and the phenomenon of atmospheric suspended particulate pollution was relatively common.The spatial distribution of the three climatic and environmental data was not balanced and had signifi cant regularity and correlation.Improving urban ventilation corridors and improving urban ventilation capacity is a feasible way to improve urban heat island effect and reduce urban climate issues such as atmospheric particulate pollution.展开更多
The existing recycling and regeneration technologies have problems,such as poor regeneration effect and low added value of products for lithium(Li)-ion battery cathode materials with a low state of health.In this work...The existing recycling and regeneration technologies have problems,such as poor regeneration effect and low added value of products for lithium(Li)-ion battery cathode materials with a low state of health.In this work,a targeted Li replenishment repair technology is proposed to improve the discharge-specific capacity and cycling stability of the repaired LiCoO_(2) cathode materials.Compared with the spent cathode material with>50%Li deficiency,the Li/Co molar ratio of the regenerated LiCoO_(2) cathode is>0.9,which completely removes the Co_(3)O_(4) impurity phase formed by the decomposition of LixCoO_(2) in the failed cathode material after repair.The repaired LiCoO_(2) cathode mater-ials exhibit better cycling stability,lower electrochemical impedance,and faster Li^(+)diffusion than the commercial materials at both 1 and 10 C.Meanwhile,Li_(1.05)CoO_(2) cathodes have higher Li replenishment efficiency and cycling stability.The energy consumption and greenhouse gas emissions of LiCoO_(2) cathodes produced by this repair method are significantly reduced compared to those using pyrometallurgical and hydro-metallurgical recycling processes.展开更多
A three-dimensional advection-diffusion model coupled with the degradation process is established for describing the transport of chemical oxygen demand (COD). Comparison of the simulated distribution of COD at the su...A three-dimensional advection-diffusion model coupled with the degradation process is established for describing the transport of chemical oxygen demand (COD). Comparison of the simulated distribution of COD at the surface in the Bohai Sea in August, 2001 with field observations, shows that the model simulates the dataset reasonably well. The Laizhou Bay, Bohai Bay, and Liaodong Bay were contaminated heavily near shore. Based on the optimal discharge flux method, the Environmental Capacity (EC) and allocated capacities of COD in the Bohai Sea are calculated. For seawater of Grades I to IV of the Chinese National Standard, the ECs of COD in the Bohai Sea were 77×104 t/a, 116×104 t/a, 154×104 t/a and 193×104 t/a, respectively. The Huanghe (Yellow) River pollutant discharge accounted for the largest percentage of COD at 14.3%, followed by that of from the Liugu River (11.5%), and other nine local rivers below 10%. The COD level in 2005 was worse than that of Grade II seawater and was beyond the environmental capacity. In average, 35% COD reduction is called to meet the standard of Grade I seawater.展开更多
The concepts of Markov process in random environment, q-matrix in random environment, and q-process in random environment are introduced. The minimal q-process in random environment is constructed and the necessary an...The concepts of Markov process in random environment, q-matrix in random environment, and q-process in random environment are introduced. The minimal q-process in random environment is constructed and the necessary and sufficient conditions for the uniqueness of q-process in random environment are given.展开更多
Let(Z_(n))be a branching process with immigration in a random environmentξ,whereξis an independent and identically distributed sequence of random variables.We show asymptotic properties for all the moments of Z_(n) ...Let(Z_(n))be a branching process with immigration in a random environmentξ,whereξis an independent and identically distributed sequence of random variables.We show asymptotic properties for all the moments of Z_(n) and describe the decay rates of the n-step transition probabilities.As applications,a large deviation principle for the sequence log Z_(n) is established,and related large deviations are also studied.展开更多
Collision avoidance decision-making models of multiple agents in virtual driving environment are studied. Based on the behavioral characteristics and hierarchical structure of the collision avoidance decision-making i...Collision avoidance decision-making models of multiple agents in virtual driving environment are studied. Based on the behavioral characteristics and hierarchical structure of the collision avoidance decision-making in real life driving, delphi approach and mathematical statistics method are introduced to construct pair-wise comparison judgment matrix of collision avoidance decision choices to each collision situation. Analytic hierarchy process (AHP) is adopted to establish the agents' collision avoidance decision-making model. To simulate drivers' characteristics, driver factors are added to categorize driving modes into impatient mode, normal mode, and the cautious mode. The results show that this model can simulate human's thinking process, and the agents in the virtual environment can deal with collision situations and make decisions to avoid collisions without intervention. The model can also reflect diversity and uncertainly of real life driving behaviors, and solves the multi-objective, multi-choice ranking priority problem in multi-vehicle collision scenarios. This collision avoidance model of multi-agents model is feasible and effective, and can provide richer and closer-to-life virtual scene for driving simulator, reflecting real-life traffic environment more truly, this model can also promote the practicality of driving simulator.展开更多
In this paper, we investigate Galton-Watson branching processes in random environments. In the case where the environmental process is a Markov chain which is positive recurrent or has a transition matrix Q (θ,α) su...In this paper, we investigate Galton-Watson branching processes in random environments. In the case where the environmental process is a Markov chain which is positive recurrent or has a transition matrix Q (θ,α) such that sup_θ Q (θ,α)> 0 for some α, we prove that the model has the asymptotic behavior being similar to that of Galton-Watson branching processes. In other case where the environments are non-stationary independent, the sufficient conditions are obtained for certain extinction and uncertain extinction for the model.展开更多
This article is a continuation of[9].Based on the discussion of random Kolmogorov forward(backward)equations,for any given q-matrix in random environment, Q(θ)=(q(θ;x,y),x,y∈X),an infinite class of q-proces...This article is a continuation of[9].Based on the discussion of random Kolmogorov forward(backward)equations,for any given q-matrix in random environment, Q(θ)=(q(θ;x,y),x,y∈X),an infinite class of q-processes in random environments satisfying the random Kolmogorov forward(backward)equation is constructed.Moreover, under some conditions,all the q-processes in random environments satisfying the random Kolmogorov forward(backward)equation are constructed.展开更多
Studying the climatic and environmental changes on different time scales in inland arid regions of Asia can greatly im‐prove our understanding of climatic influences for the Qinghai-Tibet Plateau in the context of gl...Studying the climatic and environmental changes on different time scales in inland arid regions of Asia can greatly im‐prove our understanding of climatic influences for the Qinghai-Tibet Plateau in the context of global change. Pollen, as a remnant of seed plants, is sensitive to environmental factors including precipitation, temperature and altitude, and is a clas‐sic proxy in environmental reconstruction. In the last two decades, great progress in the application of palynology to in‐land areas of Asia has highlighted the role of palynology in paleoclimatic and paleoenvironmental research. The main progress is as follows. (1) On the tectonic time scale of the late Cenozoic, the palaeoclimatological sequence has been es‐tablished on the basis of pollen percentage, concentration and taxon. Pollen data have revealed a continuous enhancement of drought in the inland arid region of Asia, in contrast to evidence acquired based on other proxies. (2) In the late Quater‐nary, an increase in herbaceous plants further supports the intensification of drought associated with global cooling. In more detail, the palynological record shows a glacial-interglacial pattern consistent with changes in global ice volume. (3) The Holocene pollen record has been established at a high resolution and across a wide range of inland areas. In general, it presents an arid grassland environment in the early Holocene, followed by the development of woody plants in the mid- to late-Holocene climate optimum. This pattern is related to moisture changes in areas dominated by the westerlies. There are also significant regional differences in the pattern and amplitude of vegetation response to the Holocene environment. (4) Modern pollen studies based on vegetation surveys, meteorological data and statistics show that topsoil palynology can better reflect regional vegetation types (e. g., grassland, meadow, desert). Drier climates yield higher pollen contents of drought-tolerant plants such as Chenopodioideae, Ephedra, and Nitriaria, while contents of Artemisia and Poaceae are greater under humid climates. Besides these achievements, problems remain in palynological research: for example, pol‐len extraction, identification, interpretation, and quantitative reconstruction. In the future, we encourage strengthened inter‐disciplinary cooperation to improve experimental methods and innovation. Firstly, we should strengthen palynological classification and improve the skill of identification;secondly, laboratory experiments are needed to better constrain pol‐len transport dynamics in water and air;thirdly, more rigorous mathematical principles will improve the reliability of re‐constructions and deepen the knowledge of plant geography;and finally, new areas and methods in palynology should be explored, for example DNA, UV-B and isotopic analysis. It is expected that palynology will continue to develop, and we hope it will continue to play an important role in the study of past climatic and environmental changes.展开更多
For continuous-state branching processes in Lévy random environments, the recursion of n-moments and the equivalent condition for the existence of general f-moments are established, where f is a positive continuo...For continuous-state branching processes in Lévy random environments, the recursion of n-moments and the equivalent condition for the existence of general f-moments are established, where f is a positive continuous function satisfying some standard conditions.展开更多
The concepts of bi-immigration birth and death density matrix in random environment and bi-immigration birth and death process in random environment are introduced. For any bi-immigration birth and death matrix in ran...The concepts of bi-immigration birth and death density matrix in random environment and bi-immigration birth and death process in random environment are introduced. For any bi-immigration birth and death matrix in random environment Q(θ) with birth rate λ 〈 death rate μ, the following results are proved, (1) there is an unique q-process in random environment, P^-(θ*(0);t) = (p^-(θ^*(0);t,i,j),i,j ≥ 0), which is ergodic, that is, lim t→∞(θ^*(0);t,i,j) = π^-(θ^*(0);j) ≥0 does not depend on i ≥ 0 and ∑j≥0π (θ*(0);j) = 1, (2) there is a bi-immigration birth and death process in random enjvironment (X^* = {X^*,t ≥ 0},ε^* = {εt,t ∈ (-∞, ∞)}) with random transition matrix P^-(θ^* (0);t) such that X^* is a strictly stationary process.展开更多
We are interested in the convergence rates of the submartingale Wn=Z_(n)/Π_(n)to its limit W,where(Π_(n))is the usually used norming sequence and(Z_(n))is a supercritical branching process with immigration(Y_(n))in ...We are interested in the convergence rates of the submartingale Wn=Z_(n)/Π_(n)to its limit W,where(Π_(n))is the usually used norming sequence and(Z_(n))is a supercritical branching process with immigration(Y_(n))in a stationary and ergodic environmentξ.Under suitable conditions,we establish the following central limit theorems and results about the rates of convergence in probability or in law:(i)W-W_(n) with suitable normalization converges to the normal law N(0,1),and similar results also hold for W_(n+k)-W_(n) for each fixed k∈N^(*);(ii)for a branching process with immigration in a finite state random environment,if W_(1) has a finite exponential moment,then so does W,and the decay rate of P(|W-W_(n)|>ε)is supergeometric;(iii)there are normalizing constants an(ξ)(that we calculate explicitly)such that a_(n)(ξ)(W-W_(n))converges in law to a mixture of the Gaussian law.展开更多
基金Sponsored by National Natural Science Foundation of China(50334020)
文摘The standard material flow diagram in steel manufacturing process was proposed to analyze the influences of various material flows on environmental load of 1tof final product.Two influence factors and reducing measures of environmental load were pointed out.The environmental load was appraised for a typical technological process in a Chinese steel plant.
基金Under the auspices of National Natural Science Foundation of China(No.41101049,41471037,41371072,41430857)University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province(No.UNPYSCT-2015054)+1 种基金Distinguished Young Scholar of Harbin Normal University(No.KGB201204)Excellent Youth Scholars of Northeast Institute of Geography and Agroecology,Chinese Academy of Sciences(No.DLSYQ13003)
文摘Understanding the underlying processes of how communities are structured remains a central question in community ecology. However, the mechanisms of the soil animal community are still unclear, especially for communities on a small scale. To evaluate the relative roles of biotic interactions and environmental and spatial processes in a soil collembolan community, a field experiment was carried out on a small scale(50 m) in the farmland ecosystem of the Sanjiang Plain, Northeast China. In August and October, 2011, we took 100 samples each month in a 50 m × 50 m plot using a spatially delimited sampling design. Variation partitioning was used to quantify the relative contributions of the spatial and environmental variables. A null model was selected to test for the non-randomness pattern of species co-occurrence and body size in assemblages of collembolans and to test whether the pattern observed was the result of environmental or biotic processes that structured the community on a small scale. The results showed that large variance was accounted for by spatial variables(18.99% in August and 21.83% in October, both were significant). There were relatively lower effects of environmental variation(3.56% in August and 1.45% in October, neither was significant), while the soil water content, soil p H and soybean height explained a significant portion of the variance that was observed in the spatial pattern of the collembolan community. Furthermore, the null model revealed more co-occurrence than expected by chance, suggesting that collembolan communities had a non-random co-occurrence pattern in both August and October. Additionally, environmental niche overlap and the body size ratio of co-occurrence showed that interspecific competition was not influential in collembolan community structuring. Considering all of the results together, the contributions of spatial and environmental processes were stronger than biotic interactions in the small-scale structuring of a soil collembolan community.
基金Supported by Key Fields of Universities in Guangdong Province (Science and Technology Service for Rural Revitalization)(2021ZDZX4023)2021 Undergraduate Teaching Quality and Teaching Construction Project of Guangdong Province (Guangdong Education Gao Han [2021] 29)+1 种基金Zhaoqing University Quality Engineering and Teaching Reform Project (zlgc 201931)Zhaoqing University Students’Innovation and Entrepreneurship Training Program in 2022 (X 202210580130)。
文摘In recent years, the beer industry is a biological food industry that consumes a lot of water, and it has developed rapidly in China. The sewage discharged from the mass production of beer poses a huge threat to the environment. In order to evaluate and better solve the possible environmental impacts of beer treatment engineering projects, a brewery project in Foshan City is taken as an example to investigate the water pollution generation links of the engineering process including surface water and groundwater. According to the relevant technical methods and standards, water pollution factors are screened, and concentration and discharge are monitored. Through comprehensive analysis, predictive evaluation is obtained. It is confirmed that the project meets the requirements of national laws and regulations and environmental protection standards.
基金National Natural Science Foundation of China(No.51475459)the Priority Academic Program Development of Jiangsu Higher Education Institutions of China(No.PAPD)
文摘Green manufacturing is a mode to realize environmental friendliness by considering the environmental impact and energy consumption in manufacturing process.In order to make an environmental friendly assessment for manufacturing process,a multi-criteria decision making( MCDM) model combined with fuzzy analytic hierarchy process( FAHP) and fuzzy technique for order preference by similarity to ideal solution( FTOPSIS) is proposed in this work.The environmental and resource criteria and manufacturing process objects are identified as the first step.Then,the weights of the criteria are calculated by FAHP.Finally,based on experts' evaluation using fuzzy words,the manufacturing process objects are ranked by FTOPSIS.The proposed methodology is applied to a gear shaft manufacturing.The sensitivity analysis and comparisons are implemented to prove its robustness and effectiveness for the ecofriendly assessment for process objects.
文摘Soil environmental capacity is defined as the maximumpermitted load of the pollutant in a cettain soil environmental unitwithin a certain temporal period. With that load, the criteria canbe maintained, production and quality of crops can be gqaranteed.Regional soil capacity is the function of physical geographiccharacteristics. In determining capacity of sierozem, key stepsinclude: (1) establishing the criteria on comprehensive basis, (2)calculating the permitted input with the application of the capacitymodel. Dynamic capacity of Cd, Cu, As and Pb for sierozem isreported and compared with that of phaiozem and red 1oam.According to the results, it is obvious that regional differentiationin capacity is distinct and the distribution pattern of permittedload is closely related to the spacial variation of physicalgeographic processes.
基金Supported by Preparation Project of Science Popularization Materials for Publicity and Education of Soil Environmental Protection,Ministry of Environmental Protection(H201606)
文摘In this paper,the development process of the construction of soil environmental quality standards in China is reviewed,and the construction situation of soil environmental quality standards in typical developed countries is introduced.According to characteristics of soil environment and practice of soil environment management in China,the relevant suggestions are discussed,thereby further perfecting construction work of soil environmental quality standards in China.
基金National Natural Science Foundation of China(No.20176045)Major State Basic Research Development Program(No.G20000263)
文摘A methodology is presented to identify environmental impact minimization alternatives for reaction processes and assess their environmental performance. The potential environmental impact (PEI) scheme can be used to visibly display the transformation relationships among different types of PEI, identify the sources of environmental impacts, and propose alternatives for eliminating or minimizing the impacts. To evaluate the environmental performance of the alternatives effectively, some new indices, such as PEI input rate of non-products, PEI output rate of non-products per profit and the PEI conversion efficiency are proposed. Finally, the application of the methodology is illustrated using an industrial case study.
基金Sponsored by National Natural Science Foundation of China(51708004)YuYou Talent Training Program of North University of Technology(215051360020XN160/009)+1 种基金General Program of Beijing Natural Science Foundation(8202017)2018 Beijing Municipal University Academic Human Resources Development:Youth Talent Support Program(PXM2018-014212-000043).
文摘The meteorological big data in Beijing area are typical multi-dimensional big data containing spatiotemporal characteristics,which have important research value for researches related to urban human settlement environment.With the help of computer programming and software processing,big data crawling,integration,extraction and multi-dimensional information fusion can be realized quickly and effectively,so as to obtain the data set needed for research and realize the target of visualization.Through big data analysis of wind environment,thermal environment and total atmospheric suspended particulate pollutants in Beijing area,it was found that the average wind speed in Beijing area decreased signifi cantly in recent 40 years,while the surface temperature increased signifi cantly;urban heat island effect was signifi cant,and the phenomenon of atmospheric suspended particulate pollution was relatively common.The spatial distribution of the three climatic and environmental data was not balanced and had signifi cant regularity and correlation.Improving urban ventilation corridors and improving urban ventilation capacity is a feasible way to improve urban heat island effect and reduce urban climate issues such as atmospheric particulate pollution.
基金supported by the National Natural Science Foundation of China (Nos. 51972030 and 51772030)the S&T Major Project of Inner Mongolia Autonomous Region in China (No. 2020ZD0018)+1 种基金the Beijing Outstanding Young Scientists Program (No. BJJWZYJH01201910007023)the Guangdong Key Laboratory of Battery Safety (No. 2019B121203008)
文摘The existing recycling and regeneration technologies have problems,such as poor regeneration effect and low added value of products for lithium(Li)-ion battery cathode materials with a low state of health.In this work,a targeted Li replenishment repair technology is proposed to improve the discharge-specific capacity and cycling stability of the repaired LiCoO_(2) cathode materials.Compared with the spent cathode material with>50%Li deficiency,the Li/Co molar ratio of the regenerated LiCoO_(2) cathode is>0.9,which completely removes the Co_(3)O_(4) impurity phase formed by the decomposition of LixCoO_(2) in the failed cathode material after repair.The repaired LiCoO_(2) cathode mater-ials exhibit better cycling stability,lower electrochemical impedance,and faster Li^(+)diffusion than the commercial materials at both 1 and 10 C.Meanwhile,Li_(1.05)CoO_(2) cathodes have higher Li replenishment efficiency and cycling stability.The energy consumption and greenhouse gas emissions of LiCoO_(2) cathodes produced by this repair method are significantly reduced compared to those using pyrometallurgical and hydro-metallurgical recycling processes.
基金Supported by 908 Program of the State Ocean Administration of China (Nos.908-02-02-02,908-02-02-03)the State Ocean Administration Foundation of China (No.200805065)
文摘A three-dimensional advection-diffusion model coupled with the degradation process is established for describing the transport of chemical oxygen demand (COD). Comparison of the simulated distribution of COD at the surface in the Bohai Sea in August, 2001 with field observations, shows that the model simulates the dataset reasonably well. The Laizhou Bay, Bohai Bay, and Liaodong Bay were contaminated heavily near shore. Based on the optimal discharge flux method, the Environmental Capacity (EC) and allocated capacities of COD in the Bohai Sea are calculated. For seawater of Grades I to IV of the Chinese National Standard, the ECs of COD in the Bohai Sea were 77×104 t/a, 116×104 t/a, 154×104 t/a and 193×104 t/a, respectively. The Huanghe (Yellow) River pollutant discharge accounted for the largest percentage of COD at 14.3%, followed by that of from the Liugu River (11.5%), and other nine local rivers below 10%. The COD level in 2005 was worse than that of Grade II seawater and was beyond the environmental capacity. In average, 35% COD reduction is called to meet the standard of Grade I seawater.
文摘The concepts of Markov process in random environment, q-matrix in random environment, and q-process in random environment are introduced. The minimal q-process in random environment is constructed and the necessary and sufficient conditions for the uniqueness of q-process in random environment are given.
基金partially supported by the National Nature Science Foundation of China(11601286,11501146)。
文摘Let(Z_(n))be a branching process with immigration in a random environmentξ,whereξis an independent and identically distributed sequence of random variables.We show asymptotic properties for all the moments of Z_(n) and describe the decay rates of the n-step transition probabilities.As applications,a large deviation principle for the sequence log Z_(n) is established,and related large deviations are also studied.
基金supported by National Basic Research Program (973 Program,No.2004CB719402)National Natural Science Foundation of China (No.60736019)Natural Science Foundation of Zhejiang Province, China(No.Y105430).
文摘Collision avoidance decision-making models of multiple agents in virtual driving environment are studied. Based on the behavioral characteristics and hierarchical structure of the collision avoidance decision-making in real life driving, delphi approach and mathematical statistics method are introduced to construct pair-wise comparison judgment matrix of collision avoidance decision choices to each collision situation. Analytic hierarchy process (AHP) is adopted to establish the agents' collision avoidance decision-making model. To simulate drivers' characteristics, driver factors are added to categorize driving modes into impatient mode, normal mode, and the cautious mode. The results show that this model can simulate human's thinking process, and the agents in the virtual environment can deal with collision situations and make decisions to avoid collisions without intervention. The model can also reflect diversity and uncertainly of real life driving behaviors, and solves the multi-objective, multi-choice ranking priority problem in multi-vehicle collision scenarios. This collision avoidance model of multi-agents model is feasible and effective, and can provide richer and closer-to-life virtual scene for driving simulator, reflecting real-life traffic environment more truly, this model can also promote the practicality of driving simulator.
文摘In this paper, we investigate Galton-Watson branching processes in random environments. In the case where the environmental process is a Markov chain which is positive recurrent or has a transition matrix Q (θ,α) such that sup_θ Q (θ,α)> 0 for some α, we prove that the model has the asymptotic behavior being similar to that of Galton-Watson branching processes. In other case where the environments are non-stationary independent, the sufficient conditions are obtained for certain extinction and uncertain extinction for the model.
基金the NNSF of China(10371092,10771185,10471148)the Foundation of Wuhan University
文摘This article is a continuation of[9].Based on the discussion of random Kolmogorov forward(backward)equations,for any given q-matrix in random environment, Q(θ)=(q(θ;x,y),x,y∈X),an infinite class of q-processes in random environments satisfying the random Kolmogorov forward(backward)equation is constructed.Moreover, under some conditions,all the q-processes in random environments satisfying the random Kolmogorov forward(backward)equation are constructed.
基金the NSFC(41772181,41807440 and 41888101)the Strategic Priority Research Program of CAS(No.XDA20070200)+4 种基金Young Top Talents Project of the"Ten Thousand Youth Program"of the Organization Department of the Central Committee of the CPCYouth Innovation Promotion Association,CAS(2014383)"Light of West China"Program,CASand the NSF of Gansu Province(18JR3RA395)We thank Miao's group members and anonymous referees for discussions and their constructive suggestions。
文摘Studying the climatic and environmental changes on different time scales in inland arid regions of Asia can greatly im‐prove our understanding of climatic influences for the Qinghai-Tibet Plateau in the context of global change. Pollen, as a remnant of seed plants, is sensitive to environmental factors including precipitation, temperature and altitude, and is a clas‐sic proxy in environmental reconstruction. In the last two decades, great progress in the application of palynology to in‐land areas of Asia has highlighted the role of palynology in paleoclimatic and paleoenvironmental research. The main progress is as follows. (1) On the tectonic time scale of the late Cenozoic, the palaeoclimatological sequence has been es‐tablished on the basis of pollen percentage, concentration and taxon. Pollen data have revealed a continuous enhancement of drought in the inland arid region of Asia, in contrast to evidence acquired based on other proxies. (2) In the late Quater‐nary, an increase in herbaceous plants further supports the intensification of drought associated with global cooling. In more detail, the palynological record shows a glacial-interglacial pattern consistent with changes in global ice volume. (3) The Holocene pollen record has been established at a high resolution and across a wide range of inland areas. In general, it presents an arid grassland environment in the early Holocene, followed by the development of woody plants in the mid- to late-Holocene climate optimum. This pattern is related to moisture changes in areas dominated by the westerlies. There are also significant regional differences in the pattern and amplitude of vegetation response to the Holocene environment. (4) Modern pollen studies based on vegetation surveys, meteorological data and statistics show that topsoil palynology can better reflect regional vegetation types (e. g., grassland, meadow, desert). Drier climates yield higher pollen contents of drought-tolerant plants such as Chenopodioideae, Ephedra, and Nitriaria, while contents of Artemisia and Poaceae are greater under humid climates. Besides these achievements, problems remain in palynological research: for example, pol‐len extraction, identification, interpretation, and quantitative reconstruction. In the future, we encourage strengthened inter‐disciplinary cooperation to improve experimental methods and innovation. Firstly, we should strengthen palynological classification and improve the skill of identification;secondly, laboratory experiments are needed to better constrain pol‐len transport dynamics in water and air;thirdly, more rigorous mathematical principles will improve the reliability of re‐constructions and deepen the knowledge of plant geography;and finally, new areas and methods in palynology should be explored, for example DNA, UV-B and isotopic analysis. It is expected that palynology will continue to develop, and we hope it will continue to play an important role in the study of past climatic and environmental changes.
基金supported by the National Natural Science Foundation of China(11531001)
文摘For continuous-state branching processes in Lévy random environments, the recursion of n-moments and the equivalent condition for the existence of general f-moments are established, where f is a positive continuous function satisfying some standard conditions.
基金Supported by the NNSF of China (10371092,10771185) the Foundation of Whuan University
文摘The concepts of bi-immigration birth and death density matrix in random environment and bi-immigration birth and death process in random environment are introduced. For any bi-immigration birth and death matrix in random environment Q(θ) with birth rate λ 〈 death rate μ, the following results are proved, (1) there is an unique q-process in random environment, P^-(θ*(0);t) = (p^-(θ^*(0);t,i,j),i,j ≥ 0), which is ergodic, that is, lim t→∞(θ^*(0);t,i,j) = π^-(θ^*(0);j) ≥0 does not depend on i ≥ 0 and ∑j≥0π (θ*(0);j) = 1, (2) there is a bi-immigration birth and death process in random enjvironment (X^* = {X^*,t ≥ 0},ε^* = {εt,t ∈ (-∞, ∞)}) with random transition matrix P^-(θ^* (0);t) such that X^* is a strictly stationary process.
基金supported by the National Natural Science Foundation of China(11571052,11731012)the Hunan Provincial Natural Science Foundation of China(2018JJ2417)the Open Fund of Hunan Provincial Key Laboratory of Mathematical Modeling and Analysis in Engineering(2018MMAEZD02)。
文摘We are interested in the convergence rates of the submartingale Wn=Z_(n)/Π_(n)to its limit W,where(Π_(n))is the usually used norming sequence and(Z_(n))is a supercritical branching process with immigration(Y_(n))in a stationary and ergodic environmentξ.Under suitable conditions,we establish the following central limit theorems and results about the rates of convergence in probability or in law:(i)W-W_(n) with suitable normalization converges to the normal law N(0,1),and similar results also hold for W_(n+k)-W_(n) for each fixed k∈N^(*);(ii)for a branching process with immigration in a finite state random environment,if W_(1) has a finite exponential moment,then so does W,and the decay rate of P(|W-W_(n)|>ε)is supergeometric;(iii)there are normalizing constants an(ξ)(that we calculate explicitly)such that a_(n)(ξ)(W-W_(n))converges in law to a mixture of the Gaussian law.
基金Supported by the National Natural Science Foundation of China (10871200)
文摘In this article, we obtain the central limit theorem and the law of the iterated logarithm for Galton-Watson processes in i.i.d, random environments.