Objective Access to improved sanitation is a fundamental human right and an important aspect of Public Health.However,an estimated thousands of people in Ghana especially,the West Mamprusi Municipal Assembly(WMMA)stil...Objective Access to improved sanitation is a fundamental human right and an important aspect of Public Health.However,an estimated thousands of people in Ghana especially,the West Mamprusi Municipal Assembly(WMMA)still have no access to adequate toilet facilities.This has brought untold health repercussions to the inhabitants,the community,and the environment at large.To address this menace,the community-led total sanitation(CLTS)was implemented.This study aimed to assess communities’perspectives on the implementation of CLTS and to understand the factors influencing its success and failures.Methods A mixed-method approach involving sequential qualitative and quantitative methods was employed in this study.Participants for the quantitative study were randomly selected and surveyed using questionnaires.The qualitative study employed focus group discussion involving purposively sampled participants including assembly members,opinion leaders,and assembly staff.Results The CLTS program in WMMA realized an apparent use of construction and proper use of household latrines leading to a reduction of open defecation free(ODF)and two communities achieving sanitized status in the history of the study area,enabling the training of latrine artisans and natural leaders to facilitate the CLTS expansion and sustainability,improved sanitation and hygiene,strengthened the enforcement of community rules and regulations and many others.Conclusion The CLTS program has received more widespread acceptance in the study area than the previous government policy of constructing public toilets,which was greeted with massive failures due to poor implementation.To ensure that gains achieved through CLTS implementation are sustained longer,it is recommended that chiefs and opinion leaders should be involved in the CLTS programs to ensure checks and enforcement.The entrenchment of bylaws and more education to address enduring myths and misconceptions will sustain the program.Subsidies in the form of sanitation loans for latrine construction materials by the government and supporting non-governmental organizations(NGOs)will be paramount in sustaining ODF.展开更多
The regeneration, tree growth, and community structure and dynamics were studied in old-growth Korean pine (Pinus koraiensis) forest.The results showed that the formation of tree form and growth character have been ob...The regeneration, tree growth, and community structure and dynamics were studied in old-growth Korean pine (Pinus koraiensis) forest.The results showed that the formation of tree form and growth character have been obviously related with the gap-phase regeneration.The ecological effects of the gap suppress the tree growth in diameter,and control that young tree stem fork in early stage.The heterogeneity of tree growth in time and space is the results of high quality in tree height and diameter.The hardwood species mixth Korean pine have different ecological effect on regeneration and tree growth of Korean pine in the early stage of gap reconstructing. Community dynamics depends on tree gaps oceurs,in which a 'cyclic sucession'between Korean pine and hard wood species may occurs.The process would take about 200 yers.展开更多
In recent years,under the influence of multiple factors such as traditional ideas and living economic conditions,the aging population in China continues to increase.Most of the elderly are more inclined to aged at hom...In recent years,under the influence of multiple factors such as traditional ideas and living economic conditions,the aging population in China continues to increase.Most of the elderly are more inclined to aged at home,and the first places for elderly activities are communities and the surrounding environment,which greatly affects the convenience of life and happiness of the elderly.In this paper,Changxindian area in Fengtai District of Beijing was as the research object,and detailed calculation and analysis were carried out by using POI data and arcGIS software.The relative location of residential areas and surrounding public toilets was explored,and the best location of public toilets in the daily walking area under the model of community home-based care for the elderly was further studied.展开更多
The performance of the chemical fuel determines the altitude,range and longevity of spacecraft in air and space exploration.Promising alternatives(e.g.,hypergolic ionic liquids or high-energy composites)with high-ener...The performance of the chemical fuel determines the altitude,range and longevity of spacecraft in air and space exploration.Promising alternatives(e.g.,hypergolic ionic liquids or high-energy composites)with high-energy density,heat of formation and fast initial rate are considered as potential chemical fuels.As the high-energy density material,hexanitrohexaazaisowurtzitane(CL-20)often serves as secondary explosive with poor self-propagating combustion behaviors.Herein,90%loading CL-20 microspheres with uniform particle sizes are precisely prepared by microfluid method,which exhibit unique hierarchical structure.The morphology,thermal behaviors,as well as combustion performance were further investigated.The results demonstrated that as-prepared spherical particles exhibit prominent thermal compatibility,and the enhanced self-sustaining combustion performance.This work provides an efficient method achieving the uniform high-energy density particles with excellent self-sustaining combustion performance.展开更多
Hollow cathode researches used to focus on the inner cavity or downstream plume,however,rarely on the gap between the throttling orifice plate and the keeper plate(T-K gap),which was found to impact the self-sustainin...Hollow cathode researches used to focus on the inner cavity or downstream plume,however,rarely on the gap between the throttling orifice plate and the keeper plate(T-K gap),which was found to impact the self-sustaining margin of hollow cathode discharge in this paper.Near the lower margin,the main power deposition and electron emission and ionization regions would migrate from inner cavity and downstream plume to the T-K gap,in which case,the source and destination of each m A current therein matter for the self-sustaining capability.Changing the metal surfaces in the T-K gap with emissive materials proved effective in lowering the lower margin by supplementing auxiliary thermionic emission,compensating electron loss on cold absorbing walls and suppressing discharge oscillations.By doing so,the lower margin of a 4 A hollow cathode was lowered from 1 to 0.1-0.2 A,enabling it to couple with low power Hall thruster without extra keeper current.展开更多
Aiming at the contradiction between the depth control accuracy and the energy consumption of the self-sustaining intelligent buoy,a low energy consumption depth control method based on historical array for real-time g...Aiming at the contradiction between the depth control accuracy and the energy consumption of the self-sustaining intelligent buoy,a low energy consumption depth control method based on historical array for real-time geostrophic oceanography(Argo)data is proposed.As known from the buoy kinematic model,the volume of the external oil sac only depends on the density and temperature of seawater at hovering depth.Hence,we use historical Argo data to extract the fitting curves of density and temperature,and obtain the relationship between the hovering depth and the volume of the external oil sac.Genetic algorithm is used to carry out the optimal energy consumption motion planning for the depth control process,and the specific motion strategy of depth control process is obtained.Compared with dual closed-loop fuzzy PID control method and radial basis function(RBF)-PID method,the proposed method reduces energy consumption to 1/50 with the same accuracy.Finally,a hardware-in-the-loop simulation system was used to verify this method.When the error caused by fitting curves is not considered,the average error is 2.62 m,the energy consumption is 3.214×10^(4)J,and the error of energy consumption is only 0.65%.It shows the effectiveness and reliability of the method as well as the advantages of comprehensively considering the accuracy and energy consumption.展开更多
To promote high-speed boundary layer transition,this paper proposes an active self-sustaining dual jets(SDJ)actuator utilizing the energy of supersonic mainflow.Employing the nanoparticle-based planar laser scattering...To promote high-speed boundary layer transition,this paper proposes an active self-sustaining dual jets(SDJ)actuator utilizing the energy of supersonic mainflow.Employing the nanoparticle-based planar laser scattering(NPLS),supersonic flat-plate boundary layer transition induced by SDJ is experimentally investigated in an Ma-2.95 low-turbulence wind tunnel.Streamwise and spanwise NPLS images are obtained to analyze fine flow structures of the whole transition process.The results reveal the transition control mechanisms that on the one hand,the jet-induced shear layer produces unstable Kelvin–Helmholtz instabilities in the wake flow,on the other hand,the jets also generates an adverse pressure gradient in the boundary layer and induce unstable streak structures,which gradually break down into turbulence downstream.The paper provides a new method for transition control of high-speed boundary layer,and have prospect both in theory and engineering application.展开更多
In this paper,we propose a local fuzzy method based on the idea of "p-strong" community to detect the disjoint and overlapping communities in networks.In the method,a refined agglomeration rule is designed for agglo...In this paper,we propose a local fuzzy method based on the idea of "p-strong" community to detect the disjoint and overlapping communities in networks.In the method,a refined agglomeration rule is designed for agglomerating nodes into local communities,and the overlapping nodes are detected based on the idea of making each community strong.We propose a contribution coefficient bvcito measure the contribution of an overlapping node to each of its belonging communities,and the fuzzy coefficients of the overlapping node can be obtained by normalizing the bvci to all its belonging communities.The running time of our method is analyzed and varies linearly with network size.We investigate our method on the computergenerated networks and real networks.The testing results indicate that the accuracy of our method in detecting disjoint communities is higher than those of the existing local methods and our method is efficient for detecting the overlapping nodes with fuzzy coefficients.Furthermore,the local optimizing scheme used in our method allows us to partly solve the resolution problem of the global modularity.展开更多
Changes in the fungal and bacterial biomass and community structure in litter after the volcanic eruptions of Mount Usu, northern Japan were investigated using a chronosequence approach, which is widely used for analy...Changes in the fungal and bacterial biomass and community structure in litter after the volcanic eruptions of Mount Usu, northern Japan were investigated using a chronosequence approach, which is widely used for analyzing vegetation succession. The vegetation changed from bare ground (10 years after the eruptions) with little plant cover and poor soil to monotonic grassland dominated by Polygonum sachalinense with undeveloped soil (33 years) and then to deciduous broad-leaved forest dominated by Populus maximowiczii with diverse species composition and well-developed soil (100 years). At three chronosequential sites, we evaluated the compositions of phospholipid fatty acids (PLFAs), carbon (C) and nitrogen (N) contents and the isotope ratios of C (δ13C) and N (δ15N) in the litter of two dominant species, Polygonum sachalinense and Populus maximowiezii. The C/N ratio, δ13C and δ15N in the litter of these two species were higher in the forest than that in the bare ground and grassland. The PLFAs gradually increased from the bare ground to the forest, showing that microbial biomass increased with the development of the soil and/or vegetation. The fungi-to-bacteria ratio of PLFA was constant at 5.3 ± 1.4 in all three sites, suggesting that fungi were predominant. A canonical correspondence analysis suggested that the PLFA comoosition was related to the successional ages and the developing soil properties (P 〈 0.05, ANOSIM). The chrono- sequential analysis effectively detected the successional changes in both microbial and plant communities.展开更多
The aerospace community widely uses difficult-to-cut materials,such as titanium alloys,high-temperature alloys,metal/ceramic/polymer matrix composites,hard and brittle materials,and geometrically complex components,su...The aerospace community widely uses difficult-to-cut materials,such as titanium alloys,high-temperature alloys,metal/ceramic/polymer matrix composites,hard and brittle materials,and geometrically complex components,such as thin-walled structures,microchannels,and complex surfaces.Mechanical machining is the main material removal process for the vast majority of aerospace components.However,many problems exist,including severe and rapid tool wear,low machining efficiency,and poor surface integrity.Nontraditional energy-assisted mechanical machining is a hybrid process that uses nontraditional energies(vibration,laser,electricity,etc)to improve the machinability of local materials and decrease the burden of mechanical machining.This provides a feasible and promising method to improve the material removal rate and surface quality,reduce process forces,and prolong tool life.However,systematic reviews of this technology are lacking with respect to the current research status and development direction.This paper reviews the recent progress in the nontraditional energy-assisted mechanical machining of difficult-to-cut materials and components in the aerospace community.In addition,this paper focuses on the processing principles,material responses under nontraditional energy,resultant forces and temperatures,material removal mechanisms,and applications of these processes,including vibration-,laser-,electric-,magnetic-,chemical-,advanced coolant-,and hybrid nontraditional energy-assisted mechanical machining.Finally,a comprehensive summary of the principles,advantages,and limitations of each hybrid process is provided,and future perspectives on forward design,device development,and sustainability of nontraditional energy-assisted mechanical machining processes are discussed.展开更多
Parameterization is a critical step in modelling ecosystem dynamics.However,assigning parameter values can be a technical challenge for structurally complex natural plant communities;uncertainties in model simulations...Parameterization is a critical step in modelling ecosystem dynamics.However,assigning parameter values can be a technical challenge for structurally complex natural plant communities;uncertainties in model simulations often arise from inappropriate model parameterization.Here we compared five methods for defining community-level specific leaf area(SLA)and leaf C:N across nine contrasting forest sites along the North-South Transect of Eastern China,including biomass-weighted average for the entire plant community(AP_BW)and four simplified selective sampling(biomass-weighted average over five dominant tree species[5DT_BW],basal area weighted average over five dominant tree species[5DT_AW],biomass-weighted average over all tree species[AT_BW]and basal area weighted average over all tree species[AT_AW]).We found that the default values for SLA and leaf C:N embedded in the Biome-BGC v4.2 were higher than the five computational methods produced across the nine sites,with deviations ranging from 28.0 to 73.3%.In addition,there were only slight deviations(<10%)between the whole plant community sampling(AP_BW)predicted NPP and the four simplified selective sampling methods,and no significant difference between the predictions of AT_BW and AP_BW except the Shennongjia site.The findings in this study highlights the critical importance of computational strategies for community-level parameterization in ecosystem process modelling,and will support the choice of parameterization methods.展开更多
Popular fermented golden pomfret(Trachinotus ovatus)is prepared via spontaneous fermentation;however,the mechanisms underlying the regulation of its flavor development remain unclear.This study shows the roles of the ...Popular fermented golden pomfret(Trachinotus ovatus)is prepared via spontaneous fermentation;however,the mechanisms underlying the regulation of its flavor development remain unclear.This study shows the roles of the complex microbiota and the dynamic changes in microbial community and flavor compounds during fish fermentation.Single-molecule real-time sequencing and molecular networking analysis revealed the correlations among different microbial genera and the relationships between microbial taxa and volatile compounds.Mechanisms underlying flavor development were also elucidated via KEGG based functional annotations.Clostridium,Shewanella,and Staphylococcus were the dominant microbial genera.Forty-nine volatile compounds were detected in the fermented fish samples,with thirteen identified as characteristic volatile compounds(ROAV>1).Volatile profiles resulted from the interactions among the microorganisms and derived enzymes,with the main metabolic pathways being amino acid biosynthesis/metabolism,carbon metabolism,and glycolysis/gluconeogenesis.This study demonstrated the approaches for distinguishing key microbiota associated with volatile compounds and monitoring the industrial production of high-quality fermented fish products.展开更多
Synthetic nitrogen(N)fertilizer has made a great contribution to the improvement of soil fertility and productivity,but excessive application of synthetic N fertilizer may cause agroecosystem risks,such as soil acidif...Synthetic nitrogen(N)fertilizer has made a great contribution to the improvement of soil fertility and productivity,but excessive application of synthetic N fertilizer may cause agroecosystem risks,such as soil acidification,groundwater contamination and biodiversity reduction.Meanwhile,organic substitution has received increasing attention for its ecologically and environmentally friendly and productivity benefits.However,the linkages between manure substitution,crop yield and the underlying microbial mechanisms remain uncertain.To bridge this gap,a three-year field experiment was conducted with five fertilization regimes:i)Control,non-fertilization;CF,conventional synthetic fertilizer application;CF_(1/2)M_(1/2),1/2 N input via synthetic fertilizer and 1/2 N input via manure;CF_(1/4)M_(3/4),1/4 N input synthetic fertilizer and 3/4 N input via manure;M,manure application.All fertilization treatments were designed to have equal N input.Our results showed that all manure substituted treatments achieved high soil fertility indexes(SFI)and productivities by increasing the soil organic carbon(SOC),total N(TN)and available phosphorus(AP)concentrations,and by altering the bacterial community diversity and composition compared with CF.SOC,AP,and the soil C:N ratio were mainly responsible for microbial community variations.The co-occurrence network revealed that SOC and AP had strong positive associations with Rhodospirillales and Burkholderiales,while TN and C:N ratio had positive and negative associations with Micromonosporaceae,respectively.These specific taxa are implicated in soil macroelement turnover.Random Forest analysis predicted that both biotic(bacterial composition and Micromonosporaceae)and abiotic(AP,SOC,SFI,and TN)factors had significant effects on crop yield.The present work strengthens our understanding of the effects of manure substitution on crop yield and provides theoretical support for optimizing fertilization strategies.展开更多
A three-year study over the Bai, Jingpo and Huayaodai communities in Yunnan Province reveals that the community development is significantly influenced in various ways by such cultural factors as the concepts of devel...A three-year study over the Bai, Jingpo and Huayaodai communities in Yunnan Province reveals that the community development is significantly influenced in various ways by such cultural factors as the concepts of development; concepts and traditions of inter-community relationships, consumption, mar- riage and gender; patterns of decision-making and production, resource and income allocation; as well as the role of information dissemination systems, religion and ritual. Based on the analysis over the interactive relevance between each factor and community development, some strategies and methods for dealing with such a cultural relevance in development projects are recommended.展开更多
In the renovation of old communities,it is important to explore ways of continuing regional cultural context,realizing harmonious regeneration of residential functions and cultural,commercial benefits when the communi...In the renovation of old communities,it is important to explore ways of continuing regional cultural context,realizing harmonious regeneration of residential functions and cultural,commercial benefits when the community environment is optimized.Taking the renovation design of Caojiaxiang Community in Chengdu City,Sichuan Province for example,we studied the utilization of marketplace culture resources in the place reconstruction of Caojiaxiang Community, summarized place reconstruction concepts and methods for the renovation of old communities,to provide valuable suggestions for the development of old communities.展开更多
Here,we characterize the temporal and spatial dynamics of forest community structure and species diversity in a subtropical evergreen broad-leaved forest in China.We found that community structure in this forest chang...Here,we characterize the temporal and spatial dynamics of forest community structure and species diversity in a subtropical evergreen broad-leaved forest in China.We found that community structure in this forest changed over a 15-year period.Specifically,renewal and death of common species was large,with the renewal of individuals mainly concentrated within a few populations,especially those of Aidia canthioides and Cryptocarya concinna.The numbers of individual deaths for common species were concentrated in the small and mid-diameter level.The spatial distribution of community species diversity fluctuated in each monitoring period,showing a more dispersed diversity after the 15-year study period,and the coefficient of variation on quadrats increased.In 2010,the death and renewal of the community and the spatial variation of species diversity were different compared to other survey years.Extreme weather may have affected species regeneration and community stability in our subtropical monsoon evergreen broad-leaved forests.Our findings suggest that strengthening the monitoring and management of the forest community will help better understand the long-and short-term causes of dynamic fluctuations of community structure and species diversity,and reveal the factors that drive changes in community structure.展开更多
With the rapid development of the city,the old city has gradually lost its former glory,and the old community accounts for a large proportion in the city,and is located in the core area of the city. At present,there a...With the rapid development of the city,the old city has gradually lost its former glory,and the old community accounts for a large proportion in the city,and is located in the core area of the city. At present,there are some problems in the old community,such as high degree of aging,poor quality of living space,and lack of outdoor space. The old community transformation is mainly in the way of ' guided reconstruction',it has completely destroyed the original historical environment and the spirit of the place. Therefore,taking Xingchaibeiyuan Community in Nanchang City as an example,we deeply explore the strategy of micro-renewal of community outdoor space,so as to provide a reference for the renewal of outdoor space in this kind of old residential area.展开更多
Overpopulation globally is an addressed issue impacting human lives, marine lives, and the surrounding ecosystem;it is adding pressure on the available resources that should be optimized to suit the needs. Yet with im...Overpopulation globally is an addressed issue impacting human lives, marine lives, and the surrounding ecosystem;it is adding pressure on the available resources that should be optimized to suit the needs. Yet with improper management of resources and monitoring of daily activities, the environment will be further negatively impacted. With overpopulation higher urbanization rates are noticed with the demand of seeking better health facilities, better education, better jobs and better well-being;this progression is driving more demand into the infrastructure sector to be able to accommodate the growth rates. Hence, the need to having sustainable communities aiming at optimizing the resources used, working towards more feasible, environmentally friendly and cost-effective communities with a better occupant’s experience is in action. Sustainable development goals (SDG) are vital goals developed by the United Nations Development Program (UNDP) in 2015 to address and guide through 17 interconnected global goals serving the previously mentioned trend. Out of the 17 goals, Sustainable Cities and Communities (goal #11) and Good Health and Well-Being (goal #3) are the focus of this paper directed towards holding a comparative analysis between the community scale commonly known and mostly used rating system Leadership of Energy and Environmental Design (LEED-Cities and Communities) (USA) versus similar rating systems like Tarsheed-Communities (Egypt) and Estidama-Pearl (UAE) rating systems meeting sustainable development goal #11. Conjointly, another complimenting comparative review of the occupant’s health and wellbeing rating systems, such as Fitwel (USA) and Well (USA) are studied under sustainable development goal #3;however, they are focused on a building scale assessment. Living Community Challenge (LCC, USA) rating system linking community rating system with health & wellbeing credits was first issued in 2006, yet is it not cost effective neither easy to apply acting as a primary step while being affordable, accessible, and easy to implement. The objective of this paper is to highlight the pros and gaps under both categories of studies of community rating system and occupants’ health & wellbeing rating systems based on scientific content and commercial acceptance and do-ability. This comparison is done via comparing credits and sections within each rating system type;this will support in addressing the focal points needed for an integrated rating system between both categories that will serve in meeting SDG Sustainable Cities and Communities (goal #11) and Good Health and Well-Being (goal #3).展开更多
Public space is an important part of a dty and also a crucial carrier for public activities. During the urban development, the overall environmental quality of old residential communities has degraded gradually for th...Public space is an important part of a dty and also a crucial carrier for public activities. During the urban development, the overall environmental quality of old residential communities has degraded gradually for the lack of maintenance and upgrading, its public spaces have failed to satisfy routine needs of residents. To remodel the vitality of public spaces in old residential communities, this paper based on the field investigation of Qingshanhu Community in Nanchang City explored the thoughts of revitalizing public spaces in old residential communities from the aspects of society and material environment, and put forward the strategies of designing vitality of public spaces in old residential communities.展开更多
There are a large number of old communities in Chinese cities that urgently need to be updated and upgraded.However,the old community renewal in the past mostly focused on the transformation of physical environment wi...There are a large number of old communities in Chinese cities that urgently need to be updated and upgraded.However,the old community renewal in the past mostly focused on the transformation of physical environment with a single goal.There is a lack of in-depth thinking about the problems presented by the public space in the old communities,and it is necessary to focus on this.The continuous occurrence of public health incidents has increased the pressure on urban development,and old communities have become shortcomings in such incidents.It is a topic worthy to study whether the emergency design update of public spaces can supplement the shortcomings of old communities in public health emergencies.Based on the background of public health emergencies,combined with the theory of resilient cities,the study analyzes the emergency design of public space in the old communities and conducts a research on the renewal strategy,taking the No.4 Courtyard of Luochengtou Community in Handan City as an example.The improvement strategies of management,transportation,structure and space are specifically put forward,in order to provide reference for the emergency design update of old communities.展开更多
文摘Objective Access to improved sanitation is a fundamental human right and an important aspect of Public Health.However,an estimated thousands of people in Ghana especially,the West Mamprusi Municipal Assembly(WMMA)still have no access to adequate toilet facilities.This has brought untold health repercussions to the inhabitants,the community,and the environment at large.To address this menace,the community-led total sanitation(CLTS)was implemented.This study aimed to assess communities’perspectives on the implementation of CLTS and to understand the factors influencing its success and failures.Methods A mixed-method approach involving sequential qualitative and quantitative methods was employed in this study.Participants for the quantitative study were randomly selected and surveyed using questionnaires.The qualitative study employed focus group discussion involving purposively sampled participants including assembly members,opinion leaders,and assembly staff.Results The CLTS program in WMMA realized an apparent use of construction and proper use of household latrines leading to a reduction of open defecation free(ODF)and two communities achieving sanitized status in the history of the study area,enabling the training of latrine artisans and natural leaders to facilitate the CLTS expansion and sustainability,improved sanitation and hygiene,strengthened the enforcement of community rules and regulations and many others.Conclusion The CLTS program has received more widespread acceptance in the study area than the previous government policy of constructing public toilets,which was greeted with massive failures due to poor implementation.To ensure that gains achieved through CLTS implementation are sustained longer,it is recommended that chiefs and opinion leaders should be involved in the CLTS programs to ensure checks and enforcement.The entrenchment of bylaws and more education to address enduring myths and misconceptions will sustain the program.Subsidies in the form of sanitation loans for latrine construction materials by the government and supporting non-governmental organizations(NGOs)will be paramount in sustaining ODF.
文摘The regeneration, tree growth, and community structure and dynamics were studied in old-growth Korean pine (Pinus koraiensis) forest.The results showed that the formation of tree form and growth character have been obviously related with the gap-phase regeneration.The ecological effects of the gap suppress the tree growth in diameter,and control that young tree stem fork in early stage.The heterogeneity of tree growth in time and space is the results of high quality in tree height and diameter.The hardwood species mixth Korean pine have different ecological effect on regeneration and tree growth of Korean pine in the early stage of gap reconstructing. Community dynamics depends on tree gaps oceurs,in which a 'cyclic sucession'between Korean pine and hard wood species may occurs.The process would take about 200 yers.
文摘In recent years,under the influence of multiple factors such as traditional ideas and living economic conditions,the aging population in China continues to increase.Most of the elderly are more inclined to aged at home,and the first places for elderly activities are communities and the surrounding environment,which greatly affects the convenience of life and happiness of the elderly.In this paper,Changxindian area in Fengtai District of Beijing was as the research object,and detailed calculation and analysis were carried out by using POI data and arcGIS software.The relative location of residential areas and surrounding public toilets was explored,and the best location of public toilets in the daily walking area under the model of community home-based care for the elderly was further studied.
基金supported by the Project of State Key Laboratory of Environment-friendly Energy Materials,Southwest University of Science and Technology(No.20fksy18)。
文摘The performance of the chemical fuel determines the altitude,range and longevity of spacecraft in air and space exploration.Promising alternatives(e.g.,hypergolic ionic liquids or high-energy composites)with high-energy density,heat of formation and fast initial rate are considered as potential chemical fuels.As the high-energy density material,hexanitrohexaazaisowurtzitane(CL-20)often serves as secondary explosive with poor self-propagating combustion behaviors.Herein,90%loading CL-20 microspheres with uniform particle sizes are precisely prepared by microfluid method,which exhibit unique hierarchical structure.The morphology,thermal behaviors,as well as combustion performance were further investigated.The results demonstrated that as-prepared spherical particles exhibit prominent thermal compatibility,and the enhanced self-sustaining combustion performance.This work provides an efficient method achieving the uniform high-energy density particles with excellent self-sustaining combustion performance.
基金National Natural Science Foundation of China(Nos.61571166 and 51736003)for supporting the research。
文摘Hollow cathode researches used to focus on the inner cavity or downstream plume,however,rarely on the gap between the throttling orifice plate and the keeper plate(T-K gap),which was found to impact the self-sustaining margin of hollow cathode discharge in this paper.Near the lower margin,the main power deposition and electron emission and ionization regions would migrate from inner cavity and downstream plume to the T-K gap,in which case,the source and destination of each m A current therein matter for the self-sustaining capability.Changing the metal surfaces in the T-K gap with emissive materials proved effective in lowering the lower margin by supplementing auxiliary thermionic emission,compensating electron loss on cold absorbing walls and suppressing discharge oscillations.By doing so,the lower margin of a 4 A hollow cathode was lowered from 1 to 0.1-0.2 A,enabling it to couple with low power Hall thruster without extra keeper current.
基金Qingdao Entrepreneurship and Innovation Leading Researchers Program(No.19-3-2-40-zhc)Key Research and Development Program of Shandong Province(Nos.2019GHY112072,2019GHY112051)Project Supported by State Key Laboratory of Precision Measuring Technology and Instruments(No.pilab1906).
文摘Aiming at the contradiction between the depth control accuracy and the energy consumption of the self-sustaining intelligent buoy,a low energy consumption depth control method based on historical array for real-time geostrophic oceanography(Argo)data is proposed.As known from the buoy kinematic model,the volume of the external oil sac only depends on the density and temperature of seawater at hovering depth.Hence,we use historical Argo data to extract the fitting curves of density and temperature,and obtain the relationship between the hovering depth and the volume of the external oil sac.Genetic algorithm is used to carry out the optimal energy consumption motion planning for the depth control process,and the specific motion strategy of depth control process is obtained.Compared with dual closed-loop fuzzy PID control method and radial basis function(RBF)-PID method,the proposed method reduces energy consumption to 1/50 with the same accuracy.Finally,a hardware-in-the-loop simulation system was used to verify this method.When the error caused by fitting curves is not considered,the average error is 2.62 m,the energy consumption is 3.214×10^(4)J,and the error of energy consumption is only 0.65%.It shows the effectiveness and reliability of the method as well as the advantages of comprehensively considering the accuracy and energy consumption.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11602299,11872374,and 51809271)
文摘To promote high-speed boundary layer transition,this paper proposes an active self-sustaining dual jets(SDJ)actuator utilizing the energy of supersonic mainflow.Employing the nanoparticle-based planar laser scattering(NPLS),supersonic flat-plate boundary layer transition induced by SDJ is experimentally investigated in an Ma-2.95 low-turbulence wind tunnel.Streamwise and spanwise NPLS images are obtained to analyze fine flow structures of the whole transition process.The results reveal the transition control mechanisms that on the one hand,the jet-induced shear layer produces unstable Kelvin–Helmholtz instabilities in the wake flow,on the other hand,the jets also generates an adverse pressure gradient in the boundary layer and induce unstable streak structures,which gradually break down into turbulence downstream.The paper provides a new method for transition control of high-speed boundary layer,and have prospect both in theory and engineering application.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51278101 and 51578149)the Science and Technology Program of Ministry of Transport of China(Grant No.2015318J33080)+1 种基金the Jiangsu Provincial Post-doctoral Science Foundation,China(Grant No.1501046B)the Fundamental Research Funds for the Central Universities,China(Grant No.Y0201500219)
文摘In this paper,we propose a local fuzzy method based on the idea of "p-strong" community to detect the disjoint and overlapping communities in networks.In the method,a refined agglomeration rule is designed for agglomerating nodes into local communities,and the overlapping nodes are detected based on the idea of making each community strong.We propose a contribution coefficient bvcito measure the contribution of an overlapping node to each of its belonging communities,and the fuzzy coefficients of the overlapping node can be obtained by normalizing the bvci to all its belonging communities.The running time of our method is analyzed and varies linearly with network size.We investigate our method on the computergenerated networks and real networks.The testing results indicate that the accuracy of our method in detecting disjoint communities is higher than those of the existing local methods and our method is efficient for detecting the overlapping nodes with fuzzy coefficients.Furthermore,the local optimizing scheme used in our method allows us to partly solve the resolution problem of the global modularity.
文摘Changes in the fungal and bacterial biomass and community structure in litter after the volcanic eruptions of Mount Usu, northern Japan were investigated using a chronosequence approach, which is widely used for analyzing vegetation succession. The vegetation changed from bare ground (10 years after the eruptions) with little plant cover and poor soil to monotonic grassland dominated by Polygonum sachalinense with undeveloped soil (33 years) and then to deciduous broad-leaved forest dominated by Populus maximowiczii with diverse species composition and well-developed soil (100 years). At three chronosequential sites, we evaluated the compositions of phospholipid fatty acids (PLFAs), carbon (C) and nitrogen (N) contents and the isotope ratios of C (δ13C) and N (δ15N) in the litter of two dominant species, Polygonum sachalinense and Populus maximowiezii. The C/N ratio, δ13C and δ15N in the litter of these two species were higher in the forest than that in the bare ground and grassland. The PLFAs gradually increased from the bare ground to the forest, showing that microbial biomass increased with the development of the soil and/or vegetation. The fungi-to-bacteria ratio of PLFA was constant at 5.3 ± 1.4 in all three sites, suggesting that fungi were predominant. A canonical correspondence analysis suggested that the PLFA comoosition was related to the successional ages and the developing soil properties (P 〈 0.05, ANOSIM). The chrono- sequential analysis effectively detected the successional changes in both microbial and plant communities.
基金supported by the National Natural Science Foundation of China(Nos.52075255,92160301,52175415,52205475,and 92060203)。
文摘The aerospace community widely uses difficult-to-cut materials,such as titanium alloys,high-temperature alloys,metal/ceramic/polymer matrix composites,hard and brittle materials,and geometrically complex components,such as thin-walled structures,microchannels,and complex surfaces.Mechanical machining is the main material removal process for the vast majority of aerospace components.However,many problems exist,including severe and rapid tool wear,low machining efficiency,and poor surface integrity.Nontraditional energy-assisted mechanical machining is a hybrid process that uses nontraditional energies(vibration,laser,electricity,etc)to improve the machinability of local materials and decrease the burden of mechanical machining.This provides a feasible and promising method to improve the material removal rate and surface quality,reduce process forces,and prolong tool life.However,systematic reviews of this technology are lacking with respect to the current research status and development direction.This paper reviews the recent progress in the nontraditional energy-assisted mechanical machining of difficult-to-cut materials and components in the aerospace community.In addition,this paper focuses on the processing principles,material responses under nontraditional energy,resultant forces and temperatures,material removal mechanisms,and applications of these processes,including vibration-,laser-,electric-,magnetic-,chemical-,advanced coolant-,and hybrid nontraditional energy-assisted mechanical machining.Finally,a comprehensive summary of the principles,advantages,and limitations of each hybrid process is provided,and future perspectives on forward design,device development,and sustainability of nontraditional energy-assisted mechanical machining processes are discussed.
基金This research was funded by the National Natural Science Foundation of China(Grant Nos.31870426).
文摘Parameterization is a critical step in modelling ecosystem dynamics.However,assigning parameter values can be a technical challenge for structurally complex natural plant communities;uncertainties in model simulations often arise from inappropriate model parameterization.Here we compared five methods for defining community-level specific leaf area(SLA)and leaf C:N across nine contrasting forest sites along the North-South Transect of Eastern China,including biomass-weighted average for the entire plant community(AP_BW)and four simplified selective sampling(biomass-weighted average over five dominant tree species[5DT_BW],basal area weighted average over five dominant tree species[5DT_AW],biomass-weighted average over all tree species[AT_BW]and basal area weighted average over all tree species[AT_AW]).We found that the default values for SLA and leaf C:N embedded in the Biome-BGC v4.2 were higher than the five computational methods produced across the nine sites,with deviations ranging from 28.0 to 73.3%.In addition,there were only slight deviations(<10%)between the whole plant community sampling(AP_BW)predicted NPP and the four simplified selective sampling methods,and no significant difference between the predictions of AT_BW and AP_BW except the Shennongjia site.The findings in this study highlights the critical importance of computational strategies for community-level parameterization in ecosystem process modelling,and will support the choice of parameterization methods.
基金supported by the National Natural Science Foundation of China(32001733)the Earmarked fund for CARS(CARS-47)+3 种基金Guangxi Natural Science Foundation Program(2021GXNSFAA196023)Guangdong Basic and Applied Basic Research Foundation(2021A1515010833)Young Talent Support Project of Guangzhou Association for Science and Technology(QT20220101142)the Special Scientific Research Funds for Central Non-profit Institutes,Chinese Academy of Fishery Sciences(2020TD69)。
文摘Popular fermented golden pomfret(Trachinotus ovatus)is prepared via spontaneous fermentation;however,the mechanisms underlying the regulation of its flavor development remain unclear.This study shows the roles of the complex microbiota and the dynamic changes in microbial community and flavor compounds during fish fermentation.Single-molecule real-time sequencing and molecular networking analysis revealed the correlations among different microbial genera and the relationships between microbial taxa and volatile compounds.Mechanisms underlying flavor development were also elucidated via KEGG based functional annotations.Clostridium,Shewanella,and Staphylococcus were the dominant microbial genera.Forty-nine volatile compounds were detected in the fermented fish samples,with thirteen identified as characteristic volatile compounds(ROAV>1).Volatile profiles resulted from the interactions among the microorganisms and derived enzymes,with the main metabolic pathways being amino acid biosynthesis/metabolism,carbon metabolism,and glycolysis/gluconeogenesis.This study demonstrated the approaches for distinguishing key microbiota associated with volatile compounds and monitoring the industrial production of high-quality fermented fish products.
基金supported by the National Key Research and Development Program of China(2022YFD2301403-2)the Major Special Project of Anhui Province,China(2021d06050003)+2 种基金the Postdoctoral Foundation of Anhui Province,China(2022B638)the Special Project of Zhongke Bengbu Technology Transfer Center,China(ZKBB202103)the Grant of the President Foundation of Hefei Institutes of Physical Science of Chinese Academy of Sciences(YZJJ2023QN37)。
文摘Synthetic nitrogen(N)fertilizer has made a great contribution to the improvement of soil fertility and productivity,but excessive application of synthetic N fertilizer may cause agroecosystem risks,such as soil acidification,groundwater contamination and biodiversity reduction.Meanwhile,organic substitution has received increasing attention for its ecologically and environmentally friendly and productivity benefits.However,the linkages between manure substitution,crop yield and the underlying microbial mechanisms remain uncertain.To bridge this gap,a three-year field experiment was conducted with five fertilization regimes:i)Control,non-fertilization;CF,conventional synthetic fertilizer application;CF_(1/2)M_(1/2),1/2 N input via synthetic fertilizer and 1/2 N input via manure;CF_(1/4)M_(3/4),1/4 N input synthetic fertilizer and 3/4 N input via manure;M,manure application.All fertilization treatments were designed to have equal N input.Our results showed that all manure substituted treatments achieved high soil fertility indexes(SFI)and productivities by increasing the soil organic carbon(SOC),total N(TN)and available phosphorus(AP)concentrations,and by altering the bacterial community diversity and composition compared with CF.SOC,AP,and the soil C:N ratio were mainly responsible for microbial community variations.The co-occurrence network revealed that SOC and AP had strong positive associations with Rhodospirillales and Burkholderiales,while TN and C:N ratio had positive and negative associations with Micromonosporaceae,respectively.These specific taxa are implicated in soil macroelement turnover.Random Forest analysis predicted that both biotic(bacterial composition and Micromonosporaceae)and abiotic(AP,SOC,SFI,and TN)factors had significant effects on crop yield.The present work strengthens our understanding of the effects of manure substitution on crop yield and provides theoretical support for optimizing fertilization strategies.
文摘A three-year study over the Bai, Jingpo and Huayaodai communities in Yunnan Province reveals that the community development is significantly influenced in various ways by such cultural factors as the concepts of development; concepts and traditions of inter-community relationships, consumption, mar- riage and gender; patterns of decision-making and production, resource and income allocation; as well as the role of information dissemination systems, religion and ritual. Based on the analysis over the interactive relevance between each factor and community development, some strategies and methods for dealing with such a cultural relevance in development projects are recommended.
文摘In the renovation of old communities,it is important to explore ways of continuing regional cultural context,realizing harmonious regeneration of residential functions and cultural,commercial benefits when the community environment is optimized.Taking the renovation design of Caojiaxiang Community in Chengdu City,Sichuan Province for example,we studied the utilization of marketplace culture resources in the place reconstruction of Caojiaxiang Community, summarized place reconstruction concepts and methods for the renovation of old communities,to provide valuable suggestions for the development of old communities.
基金funded by the Guangxi Natural Science Foundation Program (2022GXNSFAA035583 and 2020GXNSFAA159108)National Natural Science Foundation of China (32060305)+2 种基金Foundation of Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection (Guangxi Normal University)Ministry of Education, China (ERESEP 2021Z06)Chinese Forest Biodiversity Monitoring Network
文摘Here,we characterize the temporal and spatial dynamics of forest community structure and species diversity in a subtropical evergreen broad-leaved forest in China.We found that community structure in this forest changed over a 15-year period.Specifically,renewal and death of common species was large,with the renewal of individuals mainly concentrated within a few populations,especially those of Aidia canthioides and Cryptocarya concinna.The numbers of individual deaths for common species were concentrated in the small and mid-diameter level.The spatial distribution of community species diversity fluctuated in each monitoring period,showing a more dispersed diversity after the 15-year study period,and the coefficient of variation on quadrats increased.In 2010,the death and renewal of the community and the spatial variation of species diversity were different compared to other survey years.Extreme weather may have affected species regeneration and community stability in our subtropical monsoon evergreen broad-leaved forests.Our findings suggest that strengthening the monitoring and management of the forest community will help better understand the long-and short-term causes of dynamic fluctuations of community structure and species diversity,and reveal the factors that drive changes in community structure.
文摘With the rapid development of the city,the old city has gradually lost its former glory,and the old community accounts for a large proportion in the city,and is located in the core area of the city. At present,there are some problems in the old community,such as high degree of aging,poor quality of living space,and lack of outdoor space. The old community transformation is mainly in the way of ' guided reconstruction',it has completely destroyed the original historical environment and the spirit of the place. Therefore,taking Xingchaibeiyuan Community in Nanchang City as an example,we deeply explore the strategy of micro-renewal of community outdoor space,so as to provide a reference for the renewal of outdoor space in this kind of old residential area.
文摘Overpopulation globally is an addressed issue impacting human lives, marine lives, and the surrounding ecosystem;it is adding pressure on the available resources that should be optimized to suit the needs. Yet with improper management of resources and monitoring of daily activities, the environment will be further negatively impacted. With overpopulation higher urbanization rates are noticed with the demand of seeking better health facilities, better education, better jobs and better well-being;this progression is driving more demand into the infrastructure sector to be able to accommodate the growth rates. Hence, the need to having sustainable communities aiming at optimizing the resources used, working towards more feasible, environmentally friendly and cost-effective communities with a better occupant’s experience is in action. Sustainable development goals (SDG) are vital goals developed by the United Nations Development Program (UNDP) in 2015 to address and guide through 17 interconnected global goals serving the previously mentioned trend. Out of the 17 goals, Sustainable Cities and Communities (goal #11) and Good Health and Well-Being (goal #3) are the focus of this paper directed towards holding a comparative analysis between the community scale commonly known and mostly used rating system Leadership of Energy and Environmental Design (LEED-Cities and Communities) (USA) versus similar rating systems like Tarsheed-Communities (Egypt) and Estidama-Pearl (UAE) rating systems meeting sustainable development goal #11. Conjointly, another complimenting comparative review of the occupant’s health and wellbeing rating systems, such as Fitwel (USA) and Well (USA) are studied under sustainable development goal #3;however, they are focused on a building scale assessment. Living Community Challenge (LCC, USA) rating system linking community rating system with health & wellbeing credits was first issued in 2006, yet is it not cost effective neither easy to apply acting as a primary step while being affordable, accessible, and easy to implement. The objective of this paper is to highlight the pros and gaps under both categories of studies of community rating system and occupants’ health & wellbeing rating systems based on scientific content and commercial acceptance and do-ability. This comparison is done via comparing credits and sections within each rating system type;this will support in addressing the focal points needed for an integrated rating system between both categories that will serve in meeting SDG Sustainable Cities and Communities (goal #11) and Good Health and Well-Being (goal #3).
文摘Public space is an important part of a dty and also a crucial carrier for public activities. During the urban development, the overall environmental quality of old residential communities has degraded gradually for the lack of maintenance and upgrading, its public spaces have failed to satisfy routine needs of residents. To remodel the vitality of public spaces in old residential communities, this paper based on the field investigation of Qingshanhu Community in Nanchang City explored the thoughts of revitalizing public spaces in old residential communities from the aspects of society and material environment, and put forward the strategies of designing vitality of public spaces in old residential communities.
基金Sponsored by Social Science Research Project of Hebei Province in 2021 (20210301135)。
文摘There are a large number of old communities in Chinese cities that urgently need to be updated and upgraded.However,the old community renewal in the past mostly focused on the transformation of physical environment with a single goal.There is a lack of in-depth thinking about the problems presented by the public space in the old communities,and it is necessary to focus on this.The continuous occurrence of public health incidents has increased the pressure on urban development,and old communities have become shortcomings in such incidents.It is a topic worthy to study whether the emergency design update of public spaces can supplement the shortcomings of old communities in public health emergencies.Based on the background of public health emergencies,combined with the theory of resilient cities,the study analyzes the emergency design of public space in the old communities and conducts a research on the renewal strategy,taking the No.4 Courtyard of Luochengtou Community in Handan City as an example.The improvement strategies of management,transportation,structure and space are specifically put forward,in order to provide reference for the emergency design update of old communities.