The weapons system portfolio selection problem arises at the equipment demonstration stage and deals with the military application requirements.Further,the contribution rate of the system is one of the important indic...The weapons system portfolio selection problem arises at the equipment demonstration stage and deals with the military application requirements.Further,the contribution rate of the system is one of the important indicators to evaluate the role of a system,which can facilitate the weapons system portfolio selection.Therefore,combining the system contribution rate with system portfolio selection is the focus of this study.It also focuses on calculating the contribution rates of multiple equipment systems with various types of capabilities.The contribution rate is measured by establishing a hierarchical multi-criteria value model from three dimensions.Based on the value model,the feasible portfolios are developed under certain cost constraints and the optimal weapons system portfolios are obtained by using the classification optimization selection strategy.Finally,an illustrative example is presented to verify the feasibility of the proposed model.展开更多
The Three-River Source Region(TRSR)in China holds a vital position and exhibits an irreplaceable strategic importance in ecological preservation at the national level.On the basis of an in-depth study of the vegetatio...The Three-River Source Region(TRSR)in China holds a vital position and exhibits an irreplaceable strategic importance in ecological preservation at the national level.On the basis of an in-depth study of the vegetation evolution in the TRSR from 2000 to 2022,we conducted a detailed analysis of the feedback mechanism of vegetation growth to climate change and human activity for different vegetation types.During the growing season,the spatiotemporal variations of normalized difference vegetation index(NDVI)for different vegetation types in the TRSR were analyzed using the Moderate Resolution Imaging Spectroradiometer(MODIS)-NDVI data and meteorological data from 2000 to 2022.In addition,the response characteristics of vegetation to temperature,precipitation,and human activity were assessed using trend analysis,partial correlation analysis,and residual analysis.Results indicated that,after in-depth research,from 2000 to 2022,the TRSR's average NDVI during the growing season was 0.3482.The preliminary ranking of the average NDVI for different vegetation types was as follows:shrubland(0.5762)>forest(0.5443)>meadow(0.4219)>highland vegetation(0.2223)>steppe(0.2159).The NDVI during the growing season exhibited a fluctuating growth trend,with an average growth rate of 0.0018/10a(P<0.01).Notably,forests displayed a significant development trend throughout the growing season,possessing the fastest rate of change in NDVI(0.0028/10a).Moreover,the upward trends in NDVI for forests and steppes exhibited extensive spatial distributions,with significant increases accounting for 95.23%and 93.80%,respectively.The sensitivity to precipitation was significantly enhanced in other vegetation types other than highland vegetation.By contrast,steppes,meadows,and highland vegetation demonstrated relatively high vulnerability to temperature fluctuations.A further detailed analysis revealed that climate change had a significant positive impact on the TRSR from 2000 to 2022,particularly in its northwestern areas,accounting for 85.05%of the total area.Meanwhile,human activity played a notable positive role in the southwestern and southeastern areas of the TRSR,covering 62.65%of the total area.Therefore,climate change had a significantly higher impact on NDVI during the growing season in the TRSR than human activity.展开更多
The contribution rate of equipment system-of-systems architecture(ESoSA)is an important index to evaluate the equipment update,development,and architecture optimization.Since the traditional ESoSA contribution rate ev...The contribution rate of equipment system-of-systems architecture(ESoSA)is an important index to evaluate the equipment update,development,and architecture optimization.Since the traditional ESoSA contribution rate evaluation method does not make full use of the fuzzy information and uncertain information in the equipment system-of-systems(ESoS),and the Bayesian network is an effective tool to solve the uncertain information,a new ESoSA contribution rate evaluation method based on the fuzzy Bayesian network(FBN)is proposed.Firstly,based on the operation loop theory,an ESoSA is constructed considering three aspects:reconnaissance equipment,decision equipment,and strike equipment.Next,the fuzzy set theory is introduced to construct the FBN of ESoSA to deal with fuzzy information and uncertain information.Furthermore,the fuzzy importance index of the root node of the FBN is used to calculate the contribution rate of the ESoSA,and the ESoSA contribution rate evaluation model based on the root node fuzzy importance is established.Finally,the feasibility and rationality of this method are validated via an empirical case study of aviation ESoSA.Compared with traditional methods,the evaluation method based on FBN takes various failure states of equipment into consideration,is free of acquiring accurate probability of traditional equipment failure,and models the uncertainty of the relationship between equipment.The proposed method not only supplements and improves the ESoSA contribution rate assessment method,but also broadens the application scope of the Bayesian network.展开更多
Standard has played an important role in modern enterprises and society through the encouragement of technology innovation and distribution. Based on the survey of 30 typical enterprises in the field of automobile in ...Standard has played an important role in modern enterprises and society through the encouragement of technology innovation and distribution. Based on the survey of 30 typical enterprises in the field of automobile in Shanghai, this paper makes quantitative analysis on comprehensive contribution of standard to automobile industry and accomplishes the demonstration of standard comprehensive evaluation index system. The analysis shows that standardization makes obvious contribution to Shanghai automobile industry.展开更多
The contribution of the quark loop to the gluon damping rate at zero momentum is calculated using the effective perturbative expansion technique developed by Braaten and Pisarski. It is shown that in the temperature r...The contribution of the quark loop to the gluon damping rate at zero momentum is calculated using the effective perturbative expansion technique developed by Braaten and Pisarski. It is shown that in the temperature range accessible in the present heavy-ion experiments, the contribution of the quark loop can not be ignored. The numerical results show that the quark loop provides ~n apparent contribution to the gluon damping rate at temperatures of experimental interest.展开更多
A single-sweep oscillopolarographic procedure is descrital which allows detethenahon of rateconstants for reachons of oH. For a wide range of compounds, the results fit well with rate constantspreviously obtained with...A single-sweep oscillopolarographic procedure is descrital which allows detethenahon of rateconstants for reachons of oH. For a wide range of compounds, the results fit well with rate constantspreviously obtained with other methods. Rate constants for reactions of six kinds of active compoundscontalned in rheum, a tradihonal Chinese herb, have been deteboned by this method. Rcationmechanism ha5 also been discussed.展开更多
This paper presents a method combining single-indicator comprehensive evaluation and influence factor identification to measure groundwater quality. This method not only reflects groundwater quality classification wit...This paper presents a method combining single-indicator comprehensive evaluation and influence factor identification to measure groundwater quality. This method not only reflects groundwater quality classification with clear physical significance, but also divides the possibilities of man-made pollution in regional groundwater. The paper selects 6 063 representative groundwater wells in the North China Plain to evaluate 49 groundwater inorganic and organic index and comes to a conclusion: Controlled by geological environment and hydrogeological conditions, the groundwater quality in the North China Plain deteriorates from the bottom of maintain to coastal area, with Class I to III groundwater decreasing from 49% to 3.9% while Class V groundwater increasing from 21% to 86.9%; the quality of deep groundwater is better than that of shallow groundwater; the contribution rate of manganese, total hardness, total dissolved solids and iodide in shallow groundwater to over-III type water exceeds 50%; the contribution rate of nitrite in pollution index reaches 20%; while heavy metal and organic indexes have limited impact on regional groundwater quality. The North China Plain is an important economic area in China. Over decades, it has witnessed intense human activities, and water resource quantity demanded has been far greater than quantity supplied. Due to scarce surface water resource, groundwater becomes the pillar supporting regional economic development. This has led to increasing groundwater exploitation and development. According to statistics, the exploitation degree of shallow groundwater reaches 105% in the North China Plain and 118% in the Hebei Plain; the exploitation degree of deep groundwater reaches 143% in the North China Plain and 163% in the Hebei Plain. The serious over-exploitation of groundwater brings various geological environmental problems, with the worsening of groundwater quality being a typical one. Besides impact brought by human activities, the poor quality of natural water in the North China Plain is also an important factor. Therefore, to understand the current regional groundwater quality situation and to master influence factors and influence degree can provide reliable scientific protection for regional economic development.展开更多
Using the data of 545 meteorological stations in 1961-2015,according to the rainfall intensity classification standard issued by the China Meteorological Administration,the rainfall events were divided into six intens...Using the data of 545 meteorological stations in 1961-2015,according to the rainfall intensity classification standard issued by the China Meteorological Administration,the rainfall events were divided into six intensities: light rain,moderate rain,heavy rain,torrential rain,downpour and heavy downpour. The latter three were recorded as total torrential rain,and all the six were recorded as the total rainfall. In terms of the interannual rainfall and rainy days,the whole China was regarded as an object. Firstly,the annual rainfall and rainy day of different intensity of rainfalls of 545 stations in 1961-2015 were calculated. Then,the variation trend of rainfall and rainy days was calculated. Finally,the variation trend of contribution of different intensity of rainfalls and rainy days to total rainfall and rainy days were diagnosed. It obtained the following results.( i) The light rain in China was declining from 1961 to 2015,and the trend values of light rain and rainy days were-411. 44 mm/yr and-136. 99 d/yr,respectively. Heavy rain and total heavy rainfall showed an increasing trend,with rainfall and rainy day trends of 127. 02 and 463. 94 mm/yr and 7. 93 and 4. 24 d/yr,respectively. The total rainfall showed a ' hockey' phenomenon of ' first rise,then decline',and the trend values of rainfall and rainy days were 204. 29 mm/yr and-95. 81 d/yr,respectively. Except the northern region,the rainfall in most parts of China was dominated by increasing trends and was moving towards extremes.( ii) In terms of rainfall contribution rate,the contribution of light rain to total rainfall showed a declining trend,and the trend values of rainfall and rainy day contribution were both-0. 11%/yr. The contribution of other intensity rainfalls to total rainfall showed an increasing trend. The contribution of torrential rain to the total torrential rain showed a declining trend. The contribution trends of rainfall and rainy days were-0. 06% and-0. 03%/yr,respectively. The contribution of downpour and heavy downpour to total torrential rain showed an increasing trend,indicating the intensity of torrential rain in China is increasing. Although the contribution rate of different intensity of rainfalls to total rainfall was different in different areas of China,the contribution rate of heavy rainfall to total rainfall in most areas showed an increasing trend.( iii) Through comparing the rainfall and rainy days of six different intensity of rainfalls,it can be found that China’s heavy rainfall events are increasing and the rainfall intensity is developing towards extremes.展开更多
The overseas oil and gas investment evaluation is one of the core tasks in overseas investment of oil and gas companies,among which risk evaluation and benefit evaluation are the most important.This paper sets forth t...The overseas oil and gas investment evaluation is one of the core tasks in overseas investment of oil and gas companies,among which risk evaluation and benefit evaluation are the most important.This paper sets forth transmission paths of risk factors to the investment benefit by identifying 14 overseas oil and gas investment risks in four categories.On the basis of the concept of risk compensation,different compensation mechanisms specific to each risk are designed.The risk and benefit are integrated objectively to develop a comprehensive evaluation model by correcting the recoverable reserve,adjusting benefit evaluation parameters such as investments on exploration and development,and compensating for the changes in risk factors with time through dynamic discount rate.Moreover,two cases studies,namely the evaluations of Project A in Sudan and comparison among Blocks A–G,are used to describe usage method and applicable scope of such evaluation model,respectively.According to the results,oil price is a key influencing factor for enterprise internal risk and industrial risk.Risk compensation reduces comprehensive benefit of overseas oil and gas investment and undermines the investment feasibility and priority of blocks.The research findings of this paper are free from the effects of some subject factors and avoid multi-objective decision making,and also avoid the undesired repeated calculation of risk factors.展开更多
Alpine treeline, as a prominent ecological boundary between forested mountain slopes and alpine meadow/shrub, is highly complex in altitudinal distribution and sensitive to warming climate. Great efforts have been mad...Alpine treeline, as a prominent ecological boundary between forested mountain slopes and alpine meadow/shrub, is highly complex in altitudinal distribution and sensitive to warming climate. Great efforts have been made to explore their distribution patterns and ecological mechanisms that determine these patterns for more than 100 years, and quite a number of geographical and ecophysiological models have been developed to correlate treeline altitude with latitude or a latitude related temperature. However,on a global scale, all of these models have great difficulties to accurately predict treeline elevation due to the extreme diversity of treeline site conditions.One of the major reasons is that "mass elevation effect"(MEE) has not been quantified globally and related with global treeline elevations although it has been observed and its effect on treeline elevations in the Eurasian continent and Northern Hemisphere recognized. In this study, we collected and compiled a total of 594 treeline sites all over the world from literatures, and explored how MEE affects globaltreeline elevation by developing a ternary linear regression model with intra-mountain base elevation(IMBE, as a proxy of MEE), latitude and continentality as independent variables. The results indicated that IMBE, latitude and continentality together could explain 92% of global treeline elevation variability, and that IMBE contributes the most(52.2%), latitude the second(40%) and continentality the least(7.8%) to the altitudinal distribution of global treelines. In the Northern Hemisphere, the three factors' contributions amount to 50.4%, 45.9% and 3.7% respectively; in the south hemisphere, their contributions are 38.3%, 53%, and 8.7%, respectively. This indicates that MEE, virtually the heating effect of macro-landforms, is actually the most significant factor for the altitudinal distribution of treelines across the globe, and that latitude is relatively more significant for treeline elevation in the Southern Hemisphere probably due to fewer macro-landforms there.展开更多
The aim of this study was to explore appropriate index for load evaluation by analyzing.the changes of pulmonary ventilation (VE) and heart rate (HR)in 35 student volunteers under the condition of static posture and w...The aim of this study was to explore appropriate index for load evaluation by analyzing.the changes of pulmonary ventilation (VE) and heart rate (HR)in 35 student volunteers under the condition of static posture and weight holding.Each subject was asked to perform 7 kinds of static postures and 2 kinds of weight holdings. The HR was continuously measured by a remote detecting device. VE was recorded by a ventimeter for an average of 5 min. The results showed that HR was positively correlated to VE under static activities (r=0. 89), which suggested that VE as well as HR could to some degrees reflect the static load. It was better to use VE to indicate the load of weight holdings than to use HR, which, on the other hand, was more sensible in reflection of the posture load. It is better to use relative value of both of VE and HR to reflect the static load. In addition,arm-overheaded posture increase HR more significantly than any other activities.展开更多
This article proposes to assess the impact of the subprime mortgage crisis on the exchange rate channel in 6 countries of the Euro-Med zone. To do this, our analysis is based on three evaluation methods that allow us ...This article proposes to assess the impact of the subprime mortgage crisis on the exchange rate channel in 6 countries of the Euro-Med zone. To do this, our analysis is based on three evaluation methods that allow us to conclude that the exchange rate channel is better evaluated by the non-linear approach of the countries studied. Thus, the depreciation of the exchange rate adopted by the countries of the Med zone did worse macroeconomic stability and economic convergence.展开更多
Food insecurity in most dry regions in Zimbabwe has taught many people a lesson of using non timber forest products(NTFPs)to reduce food insecurity and improve livelihoods as well as poverty alleviation.The aim of the...Food insecurity in most dry regions in Zimbabwe has taught many people a lesson of using non timber forest products(NTFPs)to reduce food insecurity and improve livelihoods as well as poverty alleviation.The aim of the study was to evaluate the potential contribution of non-timber forest products to smallholder farmers in arid and semi-arid regions.The research was carried out as a survey and data was collected using interviews,questionnaires and focus group discussion.Data was analysed for descriptive statistics using IBM SPSS version 25.Results indicated that 64%were females and 36%were males with the majority of participants being married(57.6%)with only 8.8%being widowed.Results show that all respondents(100%)indicated that they obtain fruits from the forests as a major source of food during winter and rain season.Vegetables(84.2%),thatching grass(80.8%)and edible worms(62.5%)were also major non-timber forest products obtained from the forests by participants.All participants(100%)indicated that income generation,firewood and source of heat for brick moulding were major benefits they obtain from forest with vegetables(74.2%),brooms(91.7%)and improved nutrition(85.0%)being regarded as other important benefits enjoyed by local people from forests.Afforestation and reforestation were regarded as major sustainable forest management practices by all(100%)participants with agroforestry being indicated by only 12.5%since people had no knowledge about it.NTFPs has capacity of improving food security,human livelihoods and alleviate poverty.People are encouraged to harvest NTFPs sustainably to allow future use.Use of agroforestry can be a best way for managing forests sustainably,improve food security,crop yield,poverty alleviation and climate change mitigation.展开更多
To investigate the water quality of sampling in aquaculture ponds around the basic farmland protection areas in the five districts of Foshan city, and use the environmental pollution index to evaluate the condition of...To investigate the water quality of sampling in aquaculture ponds around the basic farmland protection areas in the five districts of Foshan city, and use the environmental pollution index to evaluate the condition of water quality. The results indicated that water temperature and pH of aquaculture ponds cound meet the requirements of fish normal growth,and dissolved oxygen was rich, but the water quality was over fertilized generally. In 20 investigation spots of the five districts, the content of CODCr, NH4^+-N and TP exceeded 90%, 30% and 85% respectively. The pollution degrees of the water quality from high to low in aquaculture ponds were Chancheng district,Nanhai district, Sanshui district, Shunde district, Gaoming district. The comprehensive quality index of aquaculture ponds was 1.44 in Foshan city, the water quality was polluted severly as a whole. The share rate of pollution load of TP was the highest, the second were CODCr and NH4^+-N. On the whole, the pollution of organic matter was very prominent in the water quality of aquaculture ponds around the basic farmland protection areas in Foshan city that had been eutrophicated.展开更多
A decline in atmospheric oxygen concentration is projected in the 21st century given the background of global warming.The Qinghai-Tibetan Plateau is located at a high altitude,and thus,it faces a hypoxia challenge;how...A decline in atmospheric oxygen concentration is projected in the 21st century given the background of global warming.The Qinghai-Tibetan Plateau is located at a high altitude,and thus,it faces a hypoxia challenge;however,knowledge of the factors contributing to its atmospheric oxygen concentration is still lacking.Here,we conducted joint observations of ecosystem oxygen production and carbon sinks and near-surface atmospheric oxygen concentrations on the Qinghai-Tibetan Plateau and meteorological elements at Beijing Fangshan Station.Using seasonal differences and statistical methods,we calculated the relative contribution rates of vegetation to changes in atmospheric oxygen concentration.Our results indicate that solar radiation,atmospheric humidity,and ecosystem oxygen consumption and production have a significant impact on the atmospheric oxygen concentration,and the impact shows temporal and spatial differences.Vegetation significantly impacts the oxygen concentration,with a contribution rate of 16.7%–24.5%,which is underestimated in existing research.Our findings provide important insights into the factors that influence atmospheric oxygen concentration and highlight the contribution of vegetation.To better understand the oxygen dynamics of the Qinghai-Tibetan Plateau,we recommend further field observations of soil respiration and vegetation photosynthesis to clarify the contributions of carbon storage,carbon sinks and other factors to the near-surface atmospheric oxygen concentration.展开更多
Objective: To study the predictive value of serum electrolyte combined with glomerular filtration rate (GFR) evaluation equation for prognosis of severe obstructive renal injury. Methods: A total of 69 patients with c...Objective: To study the predictive value of serum electrolyte combined with glomerular filtration rate (GFR) evaluation equation for prognosis of severe obstructive renal injury. Methods: A total of 69 patients with calculous obstructive renal impairment admitted to our hospital from May 2017 to December 2018 were selected as the research objects. Clinical data of the patients were collected, and according to the status of renal function impairment, they were divided into 37 cases of mild to moderate, 32 cases of severe, and 40 cases of health examination in the same period as the control group. The fasting serum of the subjects was separated in the morning, and the serum electrolytes and related indicators were detected by Olympus AV640 automatic biochemical analyzer, Scr-CysC GFR evaluation equation was used to calculate the GFR score of all subjects, the levels of serum sodium, potassium and GFR scores in patients with severe obstructive renal injury with different prognostic outcomes were analyzed, subject operating characteristic curve (ROC) of prognostic indicators in patients with severe obstructive renal impairment was drawn, and the prognostic values of serum Na+, K+, GFR score and their combination in patients with severe obstructive renal damage were analyzed. Results: Compared with the control group, the levels of UmAb, CysC, Scr, BUN, TC, serum sodium and potassium in mild to moderate group and severe group increased in turn, and the GFR score decreased in turn (P < 0.05). The serum sodium and potassium concentrations increased in turn and the GFR score decreased in turn at 1 month after operation (P < 0.05). Compared with the 1 day before operation, the serum sodium and potassium concentrations in mild group and severe group decreased and the GFR score increased 1 month after operation (P < 0.05). Compared with the good prognosis group, the serum sodium and potassium levels in patients with severe obstructive renal damage in the poor prognosis group increased significantly, and the GFR score decreased significantly (P<0.05). The results of ROC showed that the combined detection of Na + concentration, K+ concentration and GFR score had an AUC of 0.936 for predicting the prognosis and outcomes of patients with severe renal injury, which was significantly higher than that of the single detection (AUC of 0.796, 0.815 and 0.810, respectively). Conclusion: The serum sodium and potassium levels in patients with severe obstructive renal impairment are increased, and the GFR score is decreased. The combined detection of the three factors has certain reference value in predicting the poor prognosis of patients with severe obstructive renal impairment.展开更多
This article is based on the imbalance state of China's marine industries,focuses on how to evaluate and calculate marine industries'development level,and to enhance the comprehensive competitiveness.Based on ...This article is based on the imbalance state of China's marine industries,focuses on how to evaluate and calculate marine industries'development level,and to enhance the comprehensive competitiveness.Based on the present situation of China's marine industries,we construct the marine industries development index system and then measure the developing level of main marine industries,use detailed data and table to show the difference of marine pillar industries.After comprehensive evaluation and comparative analysis,we give some suggestions to enhance China's marine industrial competitiveness.展开更多
Most of the oil wells enter the middle and late stages of extraction. After one oil extraction, water injection is needed for secondary extraction. With a large amount of calcium and magnesium ions in the water, which...Most of the oil wells enter the middle and late stages of extraction. After one oil extraction, water injection is needed for secondary extraction. With a large amount of calcium and magnesium ions in the water, which is easy to form a large amount of insoluble scale, its formed barium sulfate and strontium sulfate scale are more difficult to handle than carbonate scale. In order to reduce the difficulty of oil production work, this paper mainly targeted the sulfate scale for experiments, and prepared the scale retardant agent CQC-1. Through orthogonal experimental screening, the mass ratio of itaconate acid:methacrylic acid:AMPS:sodium acrylic sulfonate was 2:1:1:1, increase the amount of evocating agent was 8% and the reaction time was 4h, the sulfate scale inhibitor synthesized at the temperature of 80°C had the best performance. Using scale resistance rate, degradation and salt-resistance, the experimental results showed that the scale resistance rate of CQC-1 reached 90.46%. In the four-week degradation experiment, the degradation rate reached over 71% and was maintained by 80.65% at 150°C, while the scale resistance rate still reached 80.35% in simulated saline. It has excellent scale resistance, temperature resistance, salt-resistance and degradation, and has good development prospects.展开更多
The effect of rating scales and test parts of body on the fabric-evoked prickle evaluation results are studied by carrying out subjective evaluation tests under controlled environment conditions (24±1)℃,(65±...The effect of rating scales and test parts of body on the fabric-evoked prickle evaluation results are studied by carrying out subjective evaluation tests under controlled environment conditions (24±1)℃,(65±5) %RH. Ten college female students aged about 20 were chosen as the subjects, who have participated a preliminary training on subjective prickle evaluation. The prickle of a range of 9 light-weight worsted woven wool and wool blend fabrics and a cotton fabric were tested by using a 15 rating scale and using a 010 rating scale respectively at different test parts of body respectively such as forearm, upper arm ball and neck back. The test results were statistically analyzed. It is found that there is a significant correlation coefficient between the evaluation results of using the 15 rating scale and of using the 010 rating scale. It is also found that there are highly significant correlation coefficients between the evaluation results of using the forearm prickle test and the neck back prickle test, between the evaluation results of using the neck back prickle test and the upper arm ball prickle test, and between the evaluation results of using the forearm prickle test and the upper arm ball prickle test. It is suggested that the forearm prickle test is preferable in evaluating fabric-evoked prickle for its convenience and sensitivity.展开更多
基金supported by the National Key R&D Program of China(2017YFC1405005)the National Natural Science Foundation of China(71690233)
文摘The weapons system portfolio selection problem arises at the equipment demonstration stage and deals with the military application requirements.Further,the contribution rate of the system is one of the important indicators to evaluate the role of a system,which can facilitate the weapons system portfolio selection.Therefore,combining the system contribution rate with system portfolio selection is the focus of this study.It also focuses on calculating the contribution rates of multiple equipment systems with various types of capabilities.The contribution rate is measured by establishing a hierarchical multi-criteria value model from three dimensions.Based on the value model,the feasible portfolios are developed under certain cost constraints and the optimal weapons system portfolios are obtained by using the classification optimization selection strategy.Finally,an illustrative example is presented to verify the feasibility of the proposed model.
基金supported by the National Natural Science Foundation of China (42377472, 42174055)the Jiangxi Provincial Social Science "Fourteenth Five-Year Plan" (2024) Fund Project (24GL45)+1 种基金the Research Center of Resource and Environment Economics (20RGL01)the Provincial Finance Project of Jiangxi Academy of Sciences-Young Talent Cultivation Program (2023YSBG50010)
文摘The Three-River Source Region(TRSR)in China holds a vital position and exhibits an irreplaceable strategic importance in ecological preservation at the national level.On the basis of an in-depth study of the vegetation evolution in the TRSR from 2000 to 2022,we conducted a detailed analysis of the feedback mechanism of vegetation growth to climate change and human activity for different vegetation types.During the growing season,the spatiotemporal variations of normalized difference vegetation index(NDVI)for different vegetation types in the TRSR were analyzed using the Moderate Resolution Imaging Spectroradiometer(MODIS)-NDVI data and meteorological data from 2000 to 2022.In addition,the response characteristics of vegetation to temperature,precipitation,and human activity were assessed using trend analysis,partial correlation analysis,and residual analysis.Results indicated that,after in-depth research,from 2000 to 2022,the TRSR's average NDVI during the growing season was 0.3482.The preliminary ranking of the average NDVI for different vegetation types was as follows:shrubland(0.5762)>forest(0.5443)>meadow(0.4219)>highland vegetation(0.2223)>steppe(0.2159).The NDVI during the growing season exhibited a fluctuating growth trend,with an average growth rate of 0.0018/10a(P<0.01).Notably,forests displayed a significant development trend throughout the growing season,possessing the fastest rate of change in NDVI(0.0028/10a).Moreover,the upward trends in NDVI for forests and steppes exhibited extensive spatial distributions,with significant increases accounting for 95.23%and 93.80%,respectively.The sensitivity to precipitation was significantly enhanced in other vegetation types other than highland vegetation.By contrast,steppes,meadows,and highland vegetation demonstrated relatively high vulnerability to temperature fluctuations.A further detailed analysis revealed that climate change had a significant positive impact on the TRSR from 2000 to 2022,particularly in its northwestern areas,accounting for 85.05%of the total area.Meanwhile,human activity played a notable positive role in the southwestern and southeastern areas of the TRSR,covering 62.65%of the total area.Therefore,climate change had a significantly higher impact on NDVI during the growing season in the TRSR than human activity.
基金supported by the National Key Research and Development Project(2018YFB1700802)the National Natural Science Foundation of China(72071206)the Science and Technology Innovation Plan of Hunan Province(2020RC4046).
文摘The contribution rate of equipment system-of-systems architecture(ESoSA)is an important index to evaluate the equipment update,development,and architecture optimization.Since the traditional ESoSA contribution rate evaluation method does not make full use of the fuzzy information and uncertain information in the equipment system-of-systems(ESoS),and the Bayesian network is an effective tool to solve the uncertain information,a new ESoSA contribution rate evaluation method based on the fuzzy Bayesian network(FBN)is proposed.Firstly,based on the operation loop theory,an ESoSA is constructed considering three aspects:reconnaissance equipment,decision equipment,and strike equipment.Next,the fuzzy set theory is introduced to construct the FBN of ESoSA to deal with fuzzy information and uncertain information.Furthermore,the fuzzy importance index of the root node of the FBN is used to calculate the contribution rate of the ESoSA,and the ESoSA contribution rate evaluation model based on the root node fuzzy importance is established.Finally,the feasibility and rationality of this method are validated via an empirical case study of aviation ESoSA.Compared with traditional methods,the evaluation method based on FBN takes various failure states of equipment into consideration,is free of acquiring accurate probability of traditional equipment failure,and models the uncertainty of the relationship between equipment.The proposed method not only supplements and improves the ESoSA contribution rate assessment method,but also broadens the application scope of the Bayesian network.
基金Project supported by the Shanghai Technical Standard Project(Grant No.06DZ05134)
文摘Standard has played an important role in modern enterprises and society through the encouragement of technology innovation and distribution. Based on the survey of 30 typical enterprises in the field of automobile in Shanghai, this paper makes quantitative analysis on comprehensive contribution of standard to automobile industry and accomplishes the demonstration of standard comprehensive evaluation index system. The analysis shows that standardization makes obvious contribution to Shanghai automobile industry.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11465021 and 11065010
文摘The contribution of the quark loop to the gluon damping rate at zero momentum is calculated using the effective perturbative expansion technique developed by Braaten and Pisarski. It is shown that in the temperature range accessible in the present heavy-ion experiments, the contribution of the quark loop can not be ignored. The numerical results show that the quark loop provides ~n apparent contribution to the gluon damping rate at temperatures of experimental interest.
文摘A single-sweep oscillopolarographic procedure is descrital which allows detethenahon of rateconstants for reachons of oH. For a wide range of compounds, the results fit well with rate constantspreviously obtained with other methods. Rate constants for reactions of six kinds of active compoundscontalned in rheum, a tradihonal Chinese herb, have been deteboned by this method. Rcationmechanism ha5 also been discussed.
基金jointly funded by Hebei Key Fund Project(D2015504019)Project of the Ministry of Water Resources(201501008)
文摘This paper presents a method combining single-indicator comprehensive evaluation and influence factor identification to measure groundwater quality. This method not only reflects groundwater quality classification with clear physical significance, but also divides the possibilities of man-made pollution in regional groundwater. The paper selects 6 063 representative groundwater wells in the North China Plain to evaluate 49 groundwater inorganic and organic index and comes to a conclusion: Controlled by geological environment and hydrogeological conditions, the groundwater quality in the North China Plain deteriorates from the bottom of maintain to coastal area, with Class I to III groundwater decreasing from 49% to 3.9% while Class V groundwater increasing from 21% to 86.9%; the quality of deep groundwater is better than that of shallow groundwater; the contribution rate of manganese, total hardness, total dissolved solids and iodide in shallow groundwater to over-III type water exceeds 50%; the contribution rate of nitrite in pollution index reaches 20%; while heavy metal and organic indexes have limited impact on regional groundwater quality. The North China Plain is an important economic area in China. Over decades, it has witnessed intense human activities, and water resource quantity demanded has been far greater than quantity supplied. Due to scarce surface water resource, groundwater becomes the pillar supporting regional economic development. This has led to increasing groundwater exploitation and development. According to statistics, the exploitation degree of shallow groundwater reaches 105% in the North China Plain and 118% in the Hebei Plain; the exploitation degree of deep groundwater reaches 143% in the North China Plain and 163% in the Hebei Plain. The serious over-exploitation of groundwater brings various geological environmental problems, with the worsening of groundwater quality being a typical one. Besides impact brought by human activities, the poor quality of natural water in the North China Plain is also an important factor. Therefore, to understand the current regional groundwater quality situation and to master influence factors and influence degree can provide reliable scientific protection for regional economic development.
基金Supported by Project of National Natural Science Foundation of China(41801064)China Postdoctoral Science Foundation(2019T120114+1 种基金 2019M650756)Central Asian Atmospheric Science Research Fund(CAAS201804)
文摘Using the data of 545 meteorological stations in 1961-2015,according to the rainfall intensity classification standard issued by the China Meteorological Administration,the rainfall events were divided into six intensities: light rain,moderate rain,heavy rain,torrential rain,downpour and heavy downpour. The latter three were recorded as total torrential rain,and all the six were recorded as the total rainfall. In terms of the interannual rainfall and rainy days,the whole China was regarded as an object. Firstly,the annual rainfall and rainy day of different intensity of rainfalls of 545 stations in 1961-2015 were calculated. Then,the variation trend of rainfall and rainy days was calculated. Finally,the variation trend of contribution of different intensity of rainfalls and rainy days to total rainfall and rainy days were diagnosed. It obtained the following results.( i) The light rain in China was declining from 1961 to 2015,and the trend values of light rain and rainy days were-411. 44 mm/yr and-136. 99 d/yr,respectively. Heavy rain and total heavy rainfall showed an increasing trend,with rainfall and rainy day trends of 127. 02 and 463. 94 mm/yr and 7. 93 and 4. 24 d/yr,respectively. The total rainfall showed a ' hockey' phenomenon of ' first rise,then decline',and the trend values of rainfall and rainy days were 204. 29 mm/yr and-95. 81 d/yr,respectively. Except the northern region,the rainfall in most parts of China was dominated by increasing trends and was moving towards extremes.( ii) In terms of rainfall contribution rate,the contribution of light rain to total rainfall showed a declining trend,and the trend values of rainfall and rainy day contribution were both-0. 11%/yr. The contribution of other intensity rainfalls to total rainfall showed an increasing trend. The contribution of torrential rain to the total torrential rain showed a declining trend. The contribution trends of rainfall and rainy days were-0. 06% and-0. 03%/yr,respectively. The contribution of downpour and heavy downpour to total torrential rain showed an increasing trend,indicating the intensity of torrential rain in China is increasing. Although the contribution rate of different intensity of rainfalls to total rainfall was different in different areas of China,the contribution rate of heavy rainfall to total rainfall in most areas showed an increasing trend.( iii) Through comparing the rainfall and rainy days of six different intensity of rainfalls,it can be found that China’s heavy rainfall events are increasing and the rainfall intensity is developing towards extremes.
文摘The overseas oil and gas investment evaluation is one of the core tasks in overseas investment of oil and gas companies,among which risk evaluation and benefit evaluation are the most important.This paper sets forth transmission paths of risk factors to the investment benefit by identifying 14 overseas oil and gas investment risks in four categories.On the basis of the concept of risk compensation,different compensation mechanisms specific to each risk are designed.The risk and benefit are integrated objectively to develop a comprehensive evaluation model by correcting the recoverable reserve,adjusting benefit evaluation parameters such as investments on exploration and development,and compensating for the changes in risk factors with time through dynamic discount rate.Moreover,two cases studies,namely the evaluations of Project A in Sudan and comparison among Blocks A–G,are used to describe usage method and applicable scope of such evaluation model,respectively.According to the results,oil price is a key influencing factor for enterprise internal risk and industrial risk.Risk compensation reduces comprehensive benefit of overseas oil and gas investment and undermines the investment feasibility and priority of blocks.The research findings of this paper are free from the effects of some subject factors and avoid multi-objective decision making,and also avoid the undesired repeated calculation of risk factors.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41030528 and No. 40971064)
文摘Alpine treeline, as a prominent ecological boundary between forested mountain slopes and alpine meadow/shrub, is highly complex in altitudinal distribution and sensitive to warming climate. Great efforts have been made to explore their distribution patterns and ecological mechanisms that determine these patterns for more than 100 years, and quite a number of geographical and ecophysiological models have been developed to correlate treeline altitude with latitude or a latitude related temperature. However,on a global scale, all of these models have great difficulties to accurately predict treeline elevation due to the extreme diversity of treeline site conditions.One of the major reasons is that "mass elevation effect"(MEE) has not been quantified globally and related with global treeline elevations although it has been observed and its effect on treeline elevations in the Eurasian continent and Northern Hemisphere recognized. In this study, we collected and compiled a total of 594 treeline sites all over the world from literatures, and explored how MEE affects globaltreeline elevation by developing a ternary linear regression model with intra-mountain base elevation(IMBE, as a proxy of MEE), latitude and continentality as independent variables. The results indicated that IMBE, latitude and continentality together could explain 92% of global treeline elevation variability, and that IMBE contributes the most(52.2%), latitude the second(40%) and continentality the least(7.8%) to the altitudinal distribution of global treelines. In the Northern Hemisphere, the three factors' contributions amount to 50.4%, 45.9% and 3.7% respectively; in the south hemisphere, their contributions are 38.3%, 53%, and 8.7%, respectively. This indicates that MEE, virtually the heating effect of macro-landforms, is actually the most significant factor for the altitudinal distribution of treelines across the globe, and that latitude is relatively more significant for treeline elevation in the Southern Hemisphere probably due to fewer macro-landforms there.
文摘The aim of this study was to explore appropriate index for load evaluation by analyzing.the changes of pulmonary ventilation (VE) and heart rate (HR)in 35 student volunteers under the condition of static posture and weight holding.Each subject was asked to perform 7 kinds of static postures and 2 kinds of weight holdings. The HR was continuously measured by a remote detecting device. VE was recorded by a ventimeter for an average of 5 min. The results showed that HR was positively correlated to VE under static activities (r=0. 89), which suggested that VE as well as HR could to some degrees reflect the static load. It was better to use VE to indicate the load of weight holdings than to use HR, which, on the other hand, was more sensible in reflection of the posture load. It is better to use relative value of both of VE and HR to reflect the static load. In addition,arm-overheaded posture increase HR more significantly than any other activities.
文摘This article proposes to assess the impact of the subprime mortgage crisis on the exchange rate channel in 6 countries of the Euro-Med zone. To do this, our analysis is based on three evaluation methods that allow us to conclude that the exchange rate channel is better evaluated by the non-linear approach of the countries studied. Thus, the depreciation of the exchange rate adopted by the countries of the Med zone did worse macroeconomic stability and economic convergence.
文摘Food insecurity in most dry regions in Zimbabwe has taught many people a lesson of using non timber forest products(NTFPs)to reduce food insecurity and improve livelihoods as well as poverty alleviation.The aim of the study was to evaluate the potential contribution of non-timber forest products to smallholder farmers in arid and semi-arid regions.The research was carried out as a survey and data was collected using interviews,questionnaires and focus group discussion.Data was analysed for descriptive statistics using IBM SPSS version 25.Results indicated that 64%were females and 36%were males with the majority of participants being married(57.6%)with only 8.8%being widowed.Results show that all respondents(100%)indicated that they obtain fruits from the forests as a major source of food during winter and rain season.Vegetables(84.2%),thatching grass(80.8%)and edible worms(62.5%)were also major non-timber forest products obtained from the forests by participants.All participants(100%)indicated that income generation,firewood and source of heat for brick moulding were major benefits they obtain from forest with vegetables(74.2%),brooms(91.7%)and improved nutrition(85.0%)being regarded as other important benefits enjoyed by local people from forests.Afforestation and reforestation were regarded as major sustainable forest management practices by all(100%)participants with agroforestry being indicated by only 12.5%since people had no knowledge about it.NTFPs has capacity of improving food security,human livelihoods and alleviate poverty.People are encouraged to harvest NTFPs sustainably to allow future use.Use of agroforestry can be a best way for managing forests sustainably,improve food security,crop yield,poverty alleviation and climate change mitigation.
文摘To investigate the water quality of sampling in aquaculture ponds around the basic farmland protection areas in the five districts of Foshan city, and use the environmental pollution index to evaluate the condition of water quality. The results indicated that water temperature and pH of aquaculture ponds cound meet the requirements of fish normal growth,and dissolved oxygen was rich, but the water quality was over fertilized generally. In 20 investigation spots of the five districts, the content of CODCr, NH4^+-N and TP exceeded 90%, 30% and 85% respectively. The pollution degrees of the water quality from high to low in aquaculture ponds were Chancheng district,Nanhai district, Sanshui district, Shunde district, Gaoming district. The comprehensive quality index of aquaculture ponds was 1.44 in Foshan city, the water quality was polluted severly as a whole. The share rate of pollution load of TP was the highest, the second were CODCr and NH4^+-N. On the whole, the pollution of organic matter was very prominent in the water quality of aquaculture ponds around the basic farmland protection areas in Foshan city that had been eutrophicated.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(Grant Nos.2019QZKK0606&2019QZKK0906)。
文摘A decline in atmospheric oxygen concentration is projected in the 21st century given the background of global warming.The Qinghai-Tibetan Plateau is located at a high altitude,and thus,it faces a hypoxia challenge;however,knowledge of the factors contributing to its atmospheric oxygen concentration is still lacking.Here,we conducted joint observations of ecosystem oxygen production and carbon sinks and near-surface atmospheric oxygen concentrations on the Qinghai-Tibetan Plateau and meteorological elements at Beijing Fangshan Station.Using seasonal differences and statistical methods,we calculated the relative contribution rates of vegetation to changes in atmospheric oxygen concentration.Our results indicate that solar radiation,atmospheric humidity,and ecosystem oxygen consumption and production have a significant impact on the atmospheric oxygen concentration,and the impact shows temporal and spatial differences.Vegetation significantly impacts the oxygen concentration,with a contribution rate of 16.7%–24.5%,which is underestimated in existing research.Our findings provide important insights into the factors that influence atmospheric oxygen concentration and highlight the contribution of vegetation.To better understand the oxygen dynamics of the Qinghai-Tibetan Plateau,we recommend further field observations of soil respiration and vegetation photosynthesis to clarify the contributions of carbon storage,carbon sinks and other factors to the near-surface atmospheric oxygen concentration.
基金supported by Shaanxi Natural Science Basic Research Project(2012018JM7154).
文摘Objective: To study the predictive value of serum electrolyte combined with glomerular filtration rate (GFR) evaluation equation for prognosis of severe obstructive renal injury. Methods: A total of 69 patients with calculous obstructive renal impairment admitted to our hospital from May 2017 to December 2018 were selected as the research objects. Clinical data of the patients were collected, and according to the status of renal function impairment, they were divided into 37 cases of mild to moderate, 32 cases of severe, and 40 cases of health examination in the same period as the control group. The fasting serum of the subjects was separated in the morning, and the serum electrolytes and related indicators were detected by Olympus AV640 automatic biochemical analyzer, Scr-CysC GFR evaluation equation was used to calculate the GFR score of all subjects, the levels of serum sodium, potassium and GFR scores in patients with severe obstructive renal injury with different prognostic outcomes were analyzed, subject operating characteristic curve (ROC) of prognostic indicators in patients with severe obstructive renal impairment was drawn, and the prognostic values of serum Na+, K+, GFR score and their combination in patients with severe obstructive renal damage were analyzed. Results: Compared with the control group, the levels of UmAb, CysC, Scr, BUN, TC, serum sodium and potassium in mild to moderate group and severe group increased in turn, and the GFR score decreased in turn (P < 0.05). The serum sodium and potassium concentrations increased in turn and the GFR score decreased in turn at 1 month after operation (P < 0.05). Compared with the 1 day before operation, the serum sodium and potassium concentrations in mild group and severe group decreased and the GFR score increased 1 month after operation (P < 0.05). Compared with the good prognosis group, the serum sodium and potassium levels in patients with severe obstructive renal damage in the poor prognosis group increased significantly, and the GFR score decreased significantly (P<0.05). The results of ROC showed that the combined detection of Na + concentration, K+ concentration and GFR score had an AUC of 0.936 for predicting the prognosis and outcomes of patients with severe renal injury, which was significantly higher than that of the single detection (AUC of 0.796, 0.815 and 0.810, respectively). Conclusion: The serum sodium and potassium levels in patients with severe obstructive renal impairment are increased, and the GFR score is decreased. The combined detection of the three factors has certain reference value in predicting the poor prognosis of patients with severe obstructive renal impairment.
文摘This article is based on the imbalance state of China's marine industries,focuses on how to evaluate and calculate marine industries'development level,and to enhance the comprehensive competitiveness.Based on the present situation of China's marine industries,we construct the marine industries development index system and then measure the developing level of main marine industries,use detailed data and table to show the difference of marine pillar industries.After comprehensive evaluation and comparative analysis,we give some suggestions to enhance China's marine industrial competitiveness.
文摘Most of the oil wells enter the middle and late stages of extraction. After one oil extraction, water injection is needed for secondary extraction. With a large amount of calcium and magnesium ions in the water, which is easy to form a large amount of insoluble scale, its formed barium sulfate and strontium sulfate scale are more difficult to handle than carbonate scale. In order to reduce the difficulty of oil production work, this paper mainly targeted the sulfate scale for experiments, and prepared the scale retardant agent CQC-1. Through orthogonal experimental screening, the mass ratio of itaconate acid:methacrylic acid:AMPS:sodium acrylic sulfonate was 2:1:1:1, increase the amount of evocating agent was 8% and the reaction time was 4h, the sulfate scale inhibitor synthesized at the temperature of 80°C had the best performance. Using scale resistance rate, degradation and salt-resistance, the experimental results showed that the scale resistance rate of CQC-1 reached 90.46%. In the four-week degradation experiment, the degradation rate reached over 71% and was maintained by 80.65% at 150°C, while the scale resistance rate still reached 80.35% in simulated saline. It has excellent scale resistance, temperature resistance, salt-resistance and degradation, and has good development prospects.
文摘The effect of rating scales and test parts of body on the fabric-evoked prickle evaluation results are studied by carrying out subjective evaluation tests under controlled environment conditions (24±1)℃,(65±5) %RH. Ten college female students aged about 20 were chosen as the subjects, who have participated a preliminary training on subjective prickle evaluation. The prickle of a range of 9 light-weight worsted woven wool and wool blend fabrics and a cotton fabric were tested by using a 15 rating scale and using a 010 rating scale respectively at different test parts of body respectively such as forearm, upper arm ball and neck back. The test results were statistically analyzed. It is found that there is a significant correlation coefficient between the evaluation results of using the 15 rating scale and of using the 010 rating scale. It is also found that there are highly significant correlation coefficients between the evaluation results of using the forearm prickle test and the neck back prickle test, between the evaluation results of using the neck back prickle test and the upper arm ball prickle test, and between the evaluation results of using the forearm prickle test and the upper arm ball prickle test. It is suggested that the forearm prickle test is preferable in evaluating fabric-evoked prickle for its convenience and sensitivity.