Context/objectives: The COVID-19 pandemic has disrupted all programs, potentially impacting access to health services for children under 5 years old. The Far North of Cameroon is one of the northern regions with a pre...Context/objectives: The COVID-19 pandemic has disrupted all programs, potentially impacting access to health services for children under 5 years old. The Far North of Cameroon is one of the northern regions with a prevalence of malnourished children ranging from 5% to 10%. Due to the barrier measures implemented to combat the pandemic, many parents are reluctant to take their children to healthcare facilities. Some of these children were benefiting from the Ambulatory Care Center (ACC) program prior to the COVID-19 outbreak. The main objective of this research is to assess the impact of COVID-19 on access to health services for children under 5 in the Mayo Tsanaga (MT) and Logone & Chari (LC) departments. The implementation of barrier measures could significantly increase the risk of malnutrition among children under 5 years old. Method: A cross-sectional analytical study was conducted in the MT and LC departments, employing both retrospective and prospective approaches. Data was collected through questionnaire, interview guide and a review of existing data prior to the pandemic (DHIS 2). Kobo Collect software was used for data collection, and R software was used for analysis. Results: Children who benefitted from the ACC program during the COVID-19 period were found to have a lower prevalence of malnutrition compared to those who did not benefit (OR: 0.09, CI {0.0 - 0.44}). Conclusion: COVID-19 has led to a decrease in the utilization of health facilities in both departments of the study, resulting in an increase in health issues such as malnutrition among children under 5 years old. Various policies have been implemented to improve attendance at health facilities.展开更多
Background: In Benin, malaria represents the first cause of consultation and hospitalization (48% for children under 5 years old) in health units. It also accounts for 23.1% of deaths recorded in health facilities (Mo...Background: In Benin, malaria represents the first cause of consultation and hospitalization (48% for children under 5 years old) in health units. It also accounts for 23.1% of deaths recorded in health facilities (MoH, 2019). Between the two main components of vector control adopted by Benin government, the mass distribution campaigns of Insecticide-Treated Nets (ITNs) remained the only proven cost-effective way to rapidly achieve high and equitable coverage (WHO, 2017). After the fourth mass distribution campaign conducted in 2017, the Demographic and Health Survey (DHS) data indicated that the percentage of children who slept under an ITN has increased from 20% in 2006 to 70% in 2011-2012 and to 76% in 2017-2018 while the incidence of malaria (tested positive) is increasing rapidly among children under 5 years old, growing from 36.5% in 2009 to 28.8% in 2012 and then to 51.4% in 2019. This study aims to understand this contrast by identifying the origin of the increase in ITN use over time among children under five years old and the factors which determine this use. Methods: Data from the Demographic and Health Survey (DHS) conducted in Benin respectively in 2006 and in 20018 were used during the analysis, which covered 13,445 children under five years old from 2006 DHS and 12,255 children from 2017-2018 DHS. Firstly, the data were analyzed using decomposition method to highlight the origin of the increase of ITN use over time among children under five years old. Secondly, the chi-square test analysis estimated the association between ITN use and some characteristics (wealth index, maternal or caregiver education level and child age). Finally, the logistic regression model was used to identify the main factors, which influence the net use over the study period. Results: This study shows that the improvement of basic conditions is the main origin of behavior change in the use of ITNs among children under five years old. This improvement of the basic conditions consists of making ITNs available in households and informing household members about the benefits of ITN use. So, the free ITN distribution campaigns, routine distribution, awareness campaigns about the benefits of ITN use are the strategies, which increase the household capacities and knowledge, allowing household members to make their children sleep under net. The analysis also shows that region of residence, wealth index of household, household size, religion, and child age continue to determine the ITN use among children under age 5 years old and MNCP will integrate the factors in malaria prevention strategies in order to achieve universal use of ITNs. Conclusions: Although, sleeping under ITN behavior has indeed spread among children under 5 years old, policymakers and other stakeholders should design strategies to maintain and improve the current level of ITN use to reach the collective protection threshold (80% according to WHO). Therefore, to address the challenges of universal use of ITN, the study recommends expanding the routine distribution system to private sector health centers;discussing issues related to health service utilization (particularly ITN use) within a consultation framework at the communal level. In addition, collecting qualitative and quantitative data in the Oueme region will allow better understanding of all aspects of the ITN use gap among children under 5 years.展开更多
In order to recover the strip pillar coal resources, reduce the amount of gangue mountain and realize remediation of the goaf environment in the old mining area, the raw gangue filling mining technology was proposed. ...In order to recover the strip pillar coal resources, reduce the amount of gangue mountain and realize remediation of the goaf environment in the old mining area, the raw gangue filling mining technology was proposed. According to the previous practical experience, the feasibility of the implementation of raw gangue filling mining technology in the coal-pressed area was analyzed. Through the filling gangue compaction test, the deformation under different loading stages was obtained. Further, a reasonable prediction of the deformation beyond the experimental limited loading load was made based on the experimental results. Through the deformation source analysis of the whole process of gangue filling, the key factors for controlling deformation before, during, and after filling were determined. Additionally, the proportion of deformation during different stages was quantified. Considering the protection of surface buildings, mining fullness of the working face and mining technology, the production parameters of 1209 and 1210 filling working faces were preliminarily determined. Through numerical simulation, the rationality of mining scheme was verified. Based on the practice of 1209 working face and the key factors to control the deformation of gangue filling, the mining system and process in 1210 working face were optimized. According to the measured surface rock movement, raw gangue filling mining technology can meet the requirements of surface building protection level. Especially, this paper provides a method to quantitatively calculate the equivalent mining height (EMH) of raw gangue filling and its mining deformation, which has reference significance for old mining areas.展开更多
Background: Otitis media (OM) is highly prevalent and is one of the most important causes of preventable hearing loss in developing countries and it may have long-term impacts on the children. Several hospital-based c...Background: Otitis media (OM) is highly prevalent and is one of the most important causes of preventable hearing loss in developing countries and it may have long-term impacts on the children. Several hospital-based cross-sectional studies have been conducted in East African countries to assess the prevalence of OM;however, no similar studies have been conducted in Somalia. Therefore, we conducted a hospital-based cross-sectional study to identify the prevalence and the underlying risk factors of OM among children under the age of five in Mogadishu, Somalia. Methodology: A hospital-based cross-sectional study was conducted from July 2022 to November 2022 at three main hospitals in Mogadishu, Somalia. A total of 384 children aged less than 5 years were included. Parents of these children were interviewed with a questionnaire and a clinical examination was performed for each child. The Statistical Package for Social Sciences, SPSS (Version 22, IBM, Inc.), was used for the statistical analysis. Result: The prevalence of otitis media among the 384 children recruited was 31.25% (120/384). Otitis media was significantly associated with age less than one year (P = 0.006), malnutrition (P Conclusion: In summary, the present study found that otitis media was highly prevalent (31.25%) in Mogadishu, Somalia. The majority of the affected children were younger than one year. Age of the child, malnutrition, upper respiratory tract infections, feeding in lying position, and dripping something into a child’s ear were found to significantly increase the risk of developing otitis media in children. In contrast, breastfeeding for more than one year has been found to reduce the risk of developing otitis media in children.展开更多
In this paper, artificial intelligence image recognition technology is used to improve the recognition rate of individual domestic fish and reduce the recognition time, aiming at the problem that it is difficult to ea...In this paper, artificial intelligence image recognition technology is used to improve the recognition rate of individual domestic fish and reduce the recognition time, aiming at the problem that it is difficult to easily observe the species and growth of domestic fish in the underwater non-uniform light field environment. First, starting from the image data collected by polarizing imaging technology, this paper uses subpixel convolution reconstruction to enhance the image, uses image translation and fill technology to build the family fish database, builds the Adam-Dropout-CNN (A-D-CNN) network model, and its convolution kernel size is 3 × 3. The maximum pooling was used for downsampling, and the discarding operation was added after the full connection layer to avoid the phenomenon of network overfitting. The adaptive motion estimation algorithm was used to solve the gradient sparse problem. The experiment shows that the recognition rate of A-D-CNN is 96.97% when the model is trained under the domestic fish image database, which solves the problem of low recognition rate and slow recognition speed of domestic fish in non-uniform light field.展开更多
Clear PKKP,a P wave reflects of the core-mantle boundary on the core side,is recorded by the transcontinental USArray from two deep earthquakes occurred in South America and Tonga,and one intermediate-depth earthquake...Clear PKKP,a P wave reflects of the core-mantle boundary on the core side,is recorded by the transcontinental USArray from two deep earthquakes occurred in South America and Tonga,and one intermediate-depth earthquake in the Hindu Kush region.We compare the PKKP waveforms with the direct P waves to investigate the fine structures near the core-mantle boundary,with a primary focus on the core side.We find no evidence for the existence of a sedimentary layer of lighter elements with a thickness above a few hundreds of meters beneath the reflection points of the two deep events,which are located at the Ninety-East Ridge and South Africa.On the other hand the PKKP wave duration of the Hindu Kush event is almost twice as long as that of the P wave,suggesting that multiple reflections may be occurring at the core-mantle boundary located beneath the Antarctic,which is located inside the so-called tangent cylinder of the outer core.The tangent cylinder is an imaginary cylindrical region suggested by geodynamics studies,which has different flow pattern and may have a higher concentration in lighter elements as compared to the rest of the outer core.One possible explanation of the elongated PKKP is a thin distinct layer with a thickness of a few kilometers at the top of the outer core,suggesting that precipitation of lighter elements may occur at the core-mantle boundary.Our data also indicate an extremely low QP of 312,approximately 40%of the PREM average(～780),within the large-scale low-velocity anomaly in the lowermost mantle beneath Pacific.展开更多
Desire Under the Elms was a drama written by Eugene O'Neill in 1924,which is called the first greatest drama in American history.Through analyzing the naturalistic features in this drama and the combination of nat...Desire Under the Elms was a drama written by Eugene O'Neill in 1924,which is called the first greatest drama in American history.Through analyzing the naturalistic features in this drama and the combination of naturalism and realism reflected in Desire Under the Elms,this article aims to help readers understand the lines and the relevant connotations better.展开更多
Desire under the Elms reveals a tragedy of spiritual and survival desire of human being. O'Neill creates many Bible archetypes in Desire under the Elms. The thesis analyzes and appreciates Desire under the Elms fr...Desire under the Elms reveals a tragedy of spiritual and survival desire of human being. O'Neill creates many Bible archetypes in Desire under the Elms. The thesis analyzes and appreciates Desire under the Elms from aspect of Bible archetype to highlight the destructive power of improper desires in Desire under the Elms.展开更多
Ultra-fine Ce:YAG phosphors were prepared by homogeneous precipitation under microwave irradiation method. The formation of Ce:YAG was investigated by means of XRD and DTA/TG. The purified YAG crystallized phase was o...Ultra-fine Ce:YAG phosphors were prepared by homogeneous precipitation under microwave irradiation method. The formation of Ce:YAG was investigated by means of XRD and DTA/TG. The purified YAG crystallized phase was obtained at a lower temperature (1100 ℃). Basically spherical Ce:YAG powders were indicated from TEM images, and the size of the particles is about 80 nm. Two peaks of 436 and 473 nm can be seen from the excitation spectrum in the range of 402～510 nm. A broad emission band located at 480～630 nm shows the phosphors prepared by this method have good emission properties.展开更多
Effects of soil moisture on cotton root length density (total root length per unit soil volume) and yield under drip irrigation with plastic mulch were studied through field experiments. The results indicate that spat...Effects of soil moisture on cotton root length density (total root length per unit soil volume) and yield under drip irrigation with plastic mulch were studied through field experiments. The results indicate that spatial distributions of root length density of cotton under various water treatments were basically similar. Horizontally, both root length densities of cotton in wide and narrow rows were similar, and higher than that between mulches. Vertically, root length density of cotton decreased with increasing soil depth. The distribution of root length density is different under different irrigation treatments. In conditions of over-irrigation, the root length density of cotton between mulches would increase. However, it would decrease in both the wide rows and narrow rows. The mean root length density of cotton increased with increasing irrigation water. Water stress caused the root length density to increase in lower soil layers. There is a significant correlation between root length density and yields of cotton at the flower-boll and wadding stages. The regression between irrigation amount and yield of cotton can be expressed as y = -0.0026x2+18.015x-24845 (R2 = 0.959). It showed that the irrigation volume of 3,464.4 m3/hm2 led to op-timal root length density. The yield of cotton was 6,360 .8 kg/hm2 under that amount of irrigation.展开更多
Solid backfilling mining can reduce the buildings' damage caused by mining greatly. The reduction of subsidence value, the slow advancing speed and the subsidence caused by backfilling body compaction are the main...Solid backfilling mining can reduce the buildings' damage caused by mining greatly. The reduction of subsidence value, the slow advancing speed and the subsidence caused by backfilling body compaction are the main reasons that solid backfilling mining velocity decreases significantly. Based on the research of mechanism, some principles on subsidence control of solid backfilling mining under buildings were proposed. The equivalent mining height was designed according to the fortification criteria of buildings and their attachment structures, which enables the ground movement and deformation caused by mining to be less than the corresponding fortification criteria.展开更多
It is very important to determine the extent of the fractured zone through which water can flow before coal mining under the water bodies.This paper deals with methods to obtain information about overburden rock failu...It is very important to determine the extent of the fractured zone through which water can flow before coal mining under the water bodies.This paper deals with methods to obtain information about overburden rock failure and the development of the fractured zone while coal mining in Xin'an Coal Mine.The risk of water inrush in this mine is great because 40%of the mining area is under the Xiaolangdi reservoir.Numerical simulations combined with geophysical methods were used in this paper to obtain the development law of the fractured zone under different mining conditions.The comprehensive geophysical method described in this paper has been demonstrated to accurately predict the height of the water-flow fractured zone.Results from the new model, which created from the results of numerical simulations and field measurements,were successfully used for making decisions in the Xin'an Coal Mine when mining under the Xiaolangdi Reservoir.Industrial scale experiments at the number 11201,14141 and 14191 working faces were safely carried out.These achievements provide a successful background for the evaluation and application of coal mining under large reservoirs.展开更多
High level architecture(HLA) is the open standard in the collaborative simulation field. Scholars have been paying close attention to theoretical research on and engineering applications of collaborative simulation ba...High level architecture(HLA) is the open standard in the collaborative simulation field. Scholars have been paying close attention to theoretical research on and engineering applications of collaborative simulation based on HLA/RTI, which extends HLA in various aspects like functionality and efficiency. However, related study on the load balancing problem of HLA collaborative simulation is insufficient. Without load balancing, collaborative simulation under HLA/RTI may encounter performance reduction or even fatal errors. In this paper, load balancing is further divided into static problems and dynamic problems. A multi-objective model is established and the randomness of model parameters is taken into consideration for static load balancing, which makes the model more credible. The Monte Carlo based optimization algorithm(MCOA) is excogitated to gain static load balance. For dynamic load balancing, a new type of dynamic load balancing problem is put forward with regards to the variable-structured collaborative simulation under HLA/RTI. In order to minimize the influence against the running collaborative simulation, the ordinal optimization based algorithm(OOA) is devised to shorten the optimization time. Furthermore, the two algorithms are adopted in simulation experiments of different scenarios, which demonstrate their effectiveness and efficiency. An engineering experiment about collaborative simulation under HLA/RTI of high speed electricity multiple units(EMU) is also conducted to indentify credibility of the proposed models and supportive utility of MCOA and OOA to practical engineering systems. The proposed research ensures compatibility of traditional HLA, enhances the ability for assigning simulation loads onto computing units both statically and dynamically, improves the performance of collaborative simulation system and makes full use of the hardware resources.展开更多
文摘Context/objectives: The COVID-19 pandemic has disrupted all programs, potentially impacting access to health services for children under 5 years old. The Far North of Cameroon is one of the northern regions with a prevalence of malnourished children ranging from 5% to 10%. Due to the barrier measures implemented to combat the pandemic, many parents are reluctant to take their children to healthcare facilities. Some of these children were benefiting from the Ambulatory Care Center (ACC) program prior to the COVID-19 outbreak. The main objective of this research is to assess the impact of COVID-19 on access to health services for children under 5 in the Mayo Tsanaga (MT) and Logone & Chari (LC) departments. The implementation of barrier measures could significantly increase the risk of malnutrition among children under 5 years old. Method: A cross-sectional analytical study was conducted in the MT and LC departments, employing both retrospective and prospective approaches. Data was collected through questionnaire, interview guide and a review of existing data prior to the pandemic (DHIS 2). Kobo Collect software was used for data collection, and R software was used for analysis. Results: Children who benefitted from the ACC program during the COVID-19 period were found to have a lower prevalence of malnutrition compared to those who did not benefit (OR: 0.09, CI {0.0 - 0.44}). Conclusion: COVID-19 has led to a decrease in the utilization of health facilities in both departments of the study, resulting in an increase in health issues such as malnutrition among children under 5 years old. Various policies have been implemented to improve attendance at health facilities.
文摘Background: In Benin, malaria represents the first cause of consultation and hospitalization (48% for children under 5 years old) in health units. It also accounts for 23.1% of deaths recorded in health facilities (MoH, 2019). Between the two main components of vector control adopted by Benin government, the mass distribution campaigns of Insecticide-Treated Nets (ITNs) remained the only proven cost-effective way to rapidly achieve high and equitable coverage (WHO, 2017). After the fourth mass distribution campaign conducted in 2017, the Demographic and Health Survey (DHS) data indicated that the percentage of children who slept under an ITN has increased from 20% in 2006 to 70% in 2011-2012 and to 76% in 2017-2018 while the incidence of malaria (tested positive) is increasing rapidly among children under 5 years old, growing from 36.5% in 2009 to 28.8% in 2012 and then to 51.4% in 2019. This study aims to understand this contrast by identifying the origin of the increase in ITN use over time among children under five years old and the factors which determine this use. Methods: Data from the Demographic and Health Survey (DHS) conducted in Benin respectively in 2006 and in 20018 were used during the analysis, which covered 13,445 children under five years old from 2006 DHS and 12,255 children from 2017-2018 DHS. Firstly, the data were analyzed using decomposition method to highlight the origin of the increase of ITN use over time among children under five years old. Secondly, the chi-square test analysis estimated the association between ITN use and some characteristics (wealth index, maternal or caregiver education level and child age). Finally, the logistic regression model was used to identify the main factors, which influence the net use over the study period. Results: This study shows that the improvement of basic conditions is the main origin of behavior change in the use of ITNs among children under five years old. This improvement of the basic conditions consists of making ITNs available in households and informing household members about the benefits of ITN use. So, the free ITN distribution campaigns, routine distribution, awareness campaigns about the benefits of ITN use are the strategies, which increase the household capacities and knowledge, allowing household members to make their children sleep under net. The analysis also shows that region of residence, wealth index of household, household size, religion, and child age continue to determine the ITN use among children under age 5 years old and MNCP will integrate the factors in malaria prevention strategies in order to achieve universal use of ITNs. Conclusions: Although, sleeping under ITN behavior has indeed spread among children under 5 years old, policymakers and other stakeholders should design strategies to maintain and improve the current level of ITN use to reach the collective protection threshold (80% according to WHO). Therefore, to address the challenges of universal use of ITN, the study recommends expanding the routine distribution system to private sector health centers;discussing issues related to health service utilization (particularly ITN use) within a consultation framework at the communal level. In addition, collecting qualitative and quantitative data in the Oueme region will allow better understanding of all aspects of the ITN use gap among children under 5 years.
文摘In order to recover the strip pillar coal resources, reduce the amount of gangue mountain and realize remediation of the goaf environment in the old mining area, the raw gangue filling mining technology was proposed. According to the previous practical experience, the feasibility of the implementation of raw gangue filling mining technology in the coal-pressed area was analyzed. Through the filling gangue compaction test, the deformation under different loading stages was obtained. Further, a reasonable prediction of the deformation beyond the experimental limited loading load was made based on the experimental results. Through the deformation source analysis of the whole process of gangue filling, the key factors for controlling deformation before, during, and after filling were determined. Additionally, the proportion of deformation during different stages was quantified. Considering the protection of surface buildings, mining fullness of the working face and mining technology, the production parameters of 1209 and 1210 filling working faces were preliminarily determined. Through numerical simulation, the rationality of mining scheme was verified. Based on the practice of 1209 working face and the key factors to control the deformation of gangue filling, the mining system and process in 1210 working face were optimized. According to the measured surface rock movement, raw gangue filling mining technology can meet the requirements of surface building protection level. Especially, this paper provides a method to quantitatively calculate the equivalent mining height (EMH) of raw gangue filling and its mining deformation, which has reference significance for old mining areas.
文摘Background: Otitis media (OM) is highly prevalent and is one of the most important causes of preventable hearing loss in developing countries and it may have long-term impacts on the children. Several hospital-based cross-sectional studies have been conducted in East African countries to assess the prevalence of OM;however, no similar studies have been conducted in Somalia. Therefore, we conducted a hospital-based cross-sectional study to identify the prevalence and the underlying risk factors of OM among children under the age of five in Mogadishu, Somalia. Methodology: A hospital-based cross-sectional study was conducted from July 2022 to November 2022 at three main hospitals in Mogadishu, Somalia. A total of 384 children aged less than 5 years were included. Parents of these children were interviewed with a questionnaire and a clinical examination was performed for each child. The Statistical Package for Social Sciences, SPSS (Version 22, IBM, Inc.), was used for the statistical analysis. Result: The prevalence of otitis media among the 384 children recruited was 31.25% (120/384). Otitis media was significantly associated with age less than one year (P = 0.006), malnutrition (P Conclusion: In summary, the present study found that otitis media was highly prevalent (31.25%) in Mogadishu, Somalia. The majority of the affected children were younger than one year. Age of the child, malnutrition, upper respiratory tract infections, feeding in lying position, and dripping something into a child’s ear were found to significantly increase the risk of developing otitis media in children. In contrast, breastfeeding for more than one year has been found to reduce the risk of developing otitis media in children.
文摘In this paper, artificial intelligence image recognition technology is used to improve the recognition rate of individual domestic fish and reduce the recognition time, aiming at the problem that it is difficult to easily observe the species and growth of domestic fish in the underwater non-uniform light field environment. First, starting from the image data collected by polarizing imaging technology, this paper uses subpixel convolution reconstruction to enhance the image, uses image translation and fill technology to build the family fish database, builds the Adam-Dropout-CNN (A-D-CNN) network model, and its convolution kernel size is 3 × 3. The maximum pooling was used for downsampling, and the discarding operation was added after the full connection layer to avoid the phenomenon of network overfitting. The adaptive motion estimation algorithm was used to solve the gradient sparse problem. The experiment shows that the recognition rate of A-D-CNN is 96.97% when the model is trained under the domestic fish image database, which solves the problem of low recognition rate and slow recognition speed of domestic fish in non-uniform light field.
文摘Clear PKKP,a P wave reflects of the core-mantle boundary on the core side,is recorded by the transcontinental USArray from two deep earthquakes occurred in South America and Tonga,and one intermediate-depth earthquake in the Hindu Kush region.We compare the PKKP waveforms with the direct P waves to investigate the fine structures near the core-mantle boundary,with a primary focus on the core side.We find no evidence for the existence of a sedimentary layer of lighter elements with a thickness above a few hundreds of meters beneath the reflection points of the two deep events,which are located at the Ninety-East Ridge and South Africa.On the other hand the PKKP wave duration of the Hindu Kush event is almost twice as long as that of the P wave,suggesting that multiple reflections may be occurring at the core-mantle boundary located beneath the Antarctic,which is located inside the so-called tangent cylinder of the outer core.The tangent cylinder is an imaginary cylindrical region suggested by geodynamics studies,which has different flow pattern and may have a higher concentration in lighter elements as compared to the rest of the outer core.One possible explanation of the elongated PKKP is a thin distinct layer with a thickness of a few kilometers at the top of the outer core,suggesting that precipitation of lighter elements may occur at the core-mantle boundary.Our data also indicate an extremely low QP of 312,approximately 40%of the PREM average(～780),within the large-scale low-velocity anomaly in the lowermost mantle beneath Pacific.
文摘Desire Under the Elms was a drama written by Eugene O'Neill in 1924,which is called the first greatest drama in American history.Through analyzing the naturalistic features in this drama and the combination of naturalism and realism reflected in Desire Under the Elms,this article aims to help readers understand the lines and the relevant connotations better.
文摘Desire under the Elms reveals a tragedy of spiritual and survival desire of human being. O'Neill creates many Bible archetypes in Desire under the Elms. The thesis analyzes and appreciates Desire under the Elms from aspect of Bible archetype to highlight the destructive power of improper desires in Desire under the Elms.
基金Project supported by Foundation for the Excellent Middle-Aged or Young Scientists of Shandong Province (02BS049)
文摘Ultra-fine Ce:YAG phosphors were prepared by homogeneous precipitation under microwave irradiation method. The formation of Ce:YAG was investigated by means of XRD and DTA/TG. The purified YAG crystallized phase was obtained at a lower temperature (1100 ℃). Basically spherical Ce:YAG powders were indicated from TEM images, and the size of the particles is about 80 nm. Two peaks of 436 and 473 nm can be seen from the excitation spectrum in the range of 402～510 nm. A broad emission band located at 480～630 nm shows the phosphors prepared by this method have good emission properties.
基金supported by the National 973 project (2009CB421302)the National Project (2007BAC03A0604)the key National Natural Science Foundation (40830640)
文摘Effects of soil moisture on cotton root length density (total root length per unit soil volume) and yield under drip irrigation with plastic mulch were studied through field experiments. The results indicate that spatial distributions of root length density of cotton under various water treatments were basically similar. Horizontally, both root length densities of cotton in wide and narrow rows were similar, and higher than that between mulches. Vertically, root length density of cotton decreased with increasing soil depth. The distribution of root length density is different under different irrigation treatments. In conditions of over-irrigation, the root length density of cotton between mulches would increase. However, it would decrease in both the wide rows and narrow rows. The mean root length density of cotton increased with increasing irrigation water. Water stress caused the root length density to increase in lower soil layers. There is a significant correlation between root length density and yields of cotton at the flower-boll and wadding stages. The regression between irrigation amount and yield of cotton can be expressed as y = -0.0026x2+18.015x-24845 (R2 = 0.959). It showed that the irrigation volume of 3,464.4 m3/hm2 led to op-timal root length density. The yield of cotton was 6,360 .8 kg/hm2 under that amount of irrigation.
基金Project(50834004)supported by the National Natural Science Foundation of ChinaProject(LEDM2009B01)supported by Key Laboratory for Land Environment and Disaster Monitoring of SBSMProject(SKLGP2010K002)supported by Opening Fund of State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,China
文摘Solid backfilling mining can reduce the buildings' damage caused by mining greatly. The reduction of subsidence value, the slow advancing speed and the subsidence caused by backfilling body compaction are the main reasons that solid backfilling mining velocity decreases significantly. Based on the research of mechanism, some principles on subsidence control of solid backfilling mining under buildings were proposed. The equivalent mining height was designed according to the fortification criteria of buildings and their attachment structures, which enables the ground movement and deformation caused by mining to be less than the corresponding fortification criteria.
基金the National Basic Research Program of China(No.2007CB209401) for its financial support
文摘It is very important to determine the extent of the fractured zone through which water can flow before coal mining under the water bodies.This paper deals with methods to obtain information about overburden rock failure and the development of the fractured zone while coal mining in Xin'an Coal Mine.The risk of water inrush in this mine is great because 40%of the mining area is under the Xiaolangdi reservoir.Numerical simulations combined with geophysical methods were used in this paper to obtain the development law of the fractured zone under different mining conditions.The comprehensive geophysical method described in this paper has been demonstrated to accurately predict the height of the water-flow fractured zone.Results from the new model, which created from the results of numerical simulations and field measurements,were successfully used for making decisions in the Xin'an Coal Mine when mining under the Xiaolangdi Reservoir.Industrial scale experiments at the number 11201,14141 and 14191 working faces were safely carried out.These achievements provide a successful background for the evaluation and application of coal mining under large reservoirs.
基金supported by National Science and Technology Support Program of China (Grant No. 2012BAF15G00)
文摘High level architecture(HLA) is the open standard in the collaborative simulation field. Scholars have been paying close attention to theoretical research on and engineering applications of collaborative simulation based on HLA/RTI, which extends HLA in various aspects like functionality and efficiency. However, related study on the load balancing problem of HLA collaborative simulation is insufficient. Without load balancing, collaborative simulation under HLA/RTI may encounter performance reduction or even fatal errors. In this paper, load balancing is further divided into static problems and dynamic problems. A multi-objective model is established and the randomness of model parameters is taken into consideration for static load balancing, which makes the model more credible. The Monte Carlo based optimization algorithm(MCOA) is excogitated to gain static load balance. For dynamic load balancing, a new type of dynamic load balancing problem is put forward with regards to the variable-structured collaborative simulation under HLA/RTI. In order to minimize the influence against the running collaborative simulation, the ordinal optimization based algorithm(OOA) is devised to shorten the optimization time. Furthermore, the two algorithms are adopted in simulation experiments of different scenarios, which demonstrate their effectiveness and efficiency. An engineering experiment about collaborative simulation under HLA/RTI of high speed electricity multiple units(EMU) is also conducted to indentify credibility of the proposed models and supportive utility of MCOA and OOA to practical engineering systems. The proposed research ensures compatibility of traditional HLA, enhances the ability for assigning simulation loads onto computing units both statically and dynamically, improves the performance of collaborative simulation system and makes full use of the hardware resources.
