Objective Venous thromboembolism is a highly prevalent condition after polytrauma,and recognized as an important factor contributing to poor prognosis.The aim of this study was to investigate the risk factors for lowe...Objective Venous thromboembolism is a highly prevalent condition after polytrauma,and recognized as an important factor contributing to poor prognosis.The aim of this study was to investigate the risk factors for lower extremity deep venous thrombosis(LEDVT)in a severely traumatized population and to evaluate their predictive value for LEDVT.Methods This was a retrospective,single-center observational study.All subjects were severely traumatized patients who were admitted to the Traumatic Intensive Care Unit from January 2021 to May 2024.Based on Doppler ultrasound findings of both lower extremities from the time of injury to 30 days post-injury,patients who developed LEDVT were enrolled in the LEDVT group,and those who did not develop LEDVT were enrolled in the NLEDVT group.Demographic,clinical,and laboratory data were collected upon admission.Multivariable logistic regression analysis was performed to identify risk factors for LEDVT.Receiver operating characteristic(ROC)curve was used to evaluate the overall fit of the final model.Results There were 56 patients enrolled in the LEDVT group and 81 patients in the NLEDVT group.Age,Aggregate Index of Systemic Inflammation(AISI),Systemic Inflammation Response Index(SIRI),ICU length of stay,and albumin were identified as independent risk factors for LEDVT(all P<0.05).The area under their ROC curves were 0.604,0.657,0.694,0.668,and 0.405,respectively.Combined model for early clinical prediction of LEDVT in severely traumatized patients by age,SIRI,AISI,and albumin resulted in an area under the ROC curve of 0.805(95%CI:0.73-0.88,SE=0.037).Conclusion The combination of age,SIRI,AISI,and albumin has a predictive value for LEDVT in severely traumatized patients.展开更多
Because of the contradiction between the scale of new energy installations and the continuous load growth in the central and eastern regions of China,the balance problems of the electricity market are becoming increas...Because of the contradiction between the scale of new energy installations and the continuous load growth in the central and eastern regions of China,the balance problems of the electricity market are becoming increasingly prominent,and it is urgent to solve such problems through inter-provincial electricity spot markets.First,the development history and construction status of the inter-provincial electricity spot market are summarized;second,the mechanism design of the inter-provincial electricity spot market is sorted out in terms of the market operation framework,transaction declaration,and clearing methods;subsequently,the evaluation index system of the inter-provincial electricity spot market is constructed,including four themes of electricity mutual aid and support,new energy consumption,economic benefits of market-based allocation,and social benefits of market-based allocation;finally,the operation of the inter-provincial electricity spot market is comprehensively analyzed by the algorithm based on the market operation data of 2022,which proves the feasibility and practicality of the proposed index system.展开更多
The main objective is to optimize the development of shale gas-rich areas by predicting seismic sweet spot parameters in shale reservoirs. We systematically assessed the fracture development, fracture gas content, and...The main objective is to optimize the development of shale gas-rich areas by predicting seismic sweet spot parameters in shale reservoirs. We systematically assessed the fracture development, fracture gas content, and rock brittleness in fractured gas-bearing shale reservoirs. To better characterize gas-bearing shale reservoirs with tilted fractures, we optimized the petrophysical modeling based on the equivalent medium theory. Based on the advantages of shale petrophysical modeling, we not only considered the brittle mineral fraction but also the combined effect of shale porosity, gas saturation, and total organic carbon(TOC) when optimizing the brittleness index. Due to fractures generally functioning as essential channels for fluid storage and movement, fracture density and fracture fluid identification factors are critical geophysical parameters for fractured reservoir prediction. We defined a new fracture gas indication factor(GFI) to detect fracture-effective gas content. A new linear PP-wave reflection coefficient equation for a tilted transversely isotropic(TTI) medium was rederived, realizing the direct prediction of anisotropic fracture parameters and the isotropic elasticity parameters from offset vector tile(OVT)-domain seismic data. Synthetic seismic data experiments demonstrated that the inversion algorithm based on the L_P quasinorm sparsity constraint and the split-component inversion strategy exhibits high stability and noise resistance. Finally, we applied our new prediction method to evaluate fractured gas-bearing shale reservoirs in the Sichuan Basin of China, demonstrating its effectiveness.展开更多
The effect of inhaled nano-TiO2 on lung histology and serum biochemical indexes is evaluated in healthy and adult Kunming mice（eight in each group）after exposure to TiO2 aerosols（1 500 mg/m3）in a sealed chamber.An...The effect of inhaled nano-TiO2 on lung histology and serum biochemical indexes is evaluated in healthy and adult Kunming mice（eight in each group）after exposure to TiO2 aerosols（1 500 mg/m3）in a sealed chamber.Another eight mice are exposed to indoor air to be served as a control group.Lung tissue and blood are collected after euthanizing the animals.The results show that lactate dehydrogenase（LDH）activity increases in all experimental groups.Alanine aminotransferase（ALT）activity and blood urea nitrogen（BUN）levels are increased in the group exposed to TiO2 aerosols for 28 d,and creatinine（Cr）levels are increased in 14 d and 28 d samples（P0.05）.No obvious changes are observed in other serum indexes.Lungs of mice exposed to 28 d exposure show significant but moderate increase in pulmonary inflammation,and many TiO2 particles are found in the interstitium of pulmonary alveoli.展开更多
In the process of designing self-elevating drilling unit, it is important, yet complicated, to use comparison and filtering to select the optimum scheme from the feasible ones. In this research, an index system and me...In the process of designing self-elevating drilling unit, it is important, yet complicated, to use comparison and filtering to select the optimum scheme from the feasible ones. In this research, an index system and methodology for the evaluation of self-elevating drilling unit was proposed. Based on this, a multi-objective combinatorial optimization model was developed, using the improved grey relation Analysis （GRA）, in which the analytic hierarchy process （AHP） was used to determine the weights of the evaluating indices. It considered the connections within the indices, reflecting the objective nature of things, and also considered the subjective interests of ship owners and the needs of designers. The evaluation index system and evaluation method can be used in the selection of an optimal scheme and advanced assessment. A case study shows the index system and evaluation method are scientific, reasonable, and easy to put into practice. At the same time, such an evaluation index system and evaluation method will be helpful for making decisions for other mobile platforms.展开更多
Forest structure is fundamental in determining ecosystem function,yet the impact of bamboo invasion on these structural characteristics remains unclear.We investigated 219 invasion transects at 41 sites across the dis...Forest structure is fundamental in determining ecosystem function,yet the impact of bamboo invasion on these structural characteristics remains unclear.We investigated 219 invasion transects at 41 sites across the distribution areas of Moso bamboo(Phyllostachys edulis)in China to explore the effects of bamboo invasion on forest structural attributes and diameter–height allometries by comparing paired plots of bamboo,mixed bamboo-tree,and non-bamboo forests along the transects.We found that bamboo invasion decreased the mean and maximum diameter at breast height,maximum height,and total basal area,but increased the mean height,stem density,and scaling exponent for stands.Bamboo also had a higher scaling exponent than tree,particularly in mixed forests,suggesting a greater allocation of biomass to height growth.As invasion intensity increased,bamboo allometry became more plastic and decreased significantly,whereas tree allometry was indirectly promoted by increasing stem density.Additionally,a humid climate may favour the scaling exponents for both bamboo and tree,with only minor contributions from topsoil moisture and nitrogen content.The inherent superiority of diameter–height allometry allows bamboo to outcompete tree and contributes to its invasive success.Our findings provide a theoretical basis for understanding the causes and consequences of bamboo invasion.展开更多
BACKGROUND:This study aims to explore the causal relationship of body weight,body mass index(BMI),and waist circumference (WC) with the risk of cardiac arrest (CA) using two-sample Mendelian randomization (MR).METHODS...BACKGROUND:This study aims to explore the causal relationship of body weight,body mass index(BMI),and waist circumference (WC) with the risk of cardiac arrest (CA) using two-sample Mendelian randomization (MR).METHODS:Data were summarized using genome-wide association studies (GWAS).Twosample MR analyses were performed using the inverse variance weighting (IVW) method,the weighted median method,and the MR-Egger analysis.Heterogeneity test and sensitivity analysis were performed using Cochran’s Q test and the leave-one-out method,respectively.The Steiger test was used to detect reverse causality.Bayesian model-averaged MR was used to identify the most influential risk factors.RESULTS:A total of 13 GWAS data were collected for BMI,body weight and WC.IVW analyses showed a positive correlation of body weight,BMI,and WC with CA (all OR>1 and P<0.05),with MR-Egger and weighted median methods confirming the IVW findings.No horizontal pleiotropy or heterogeneity was observed.Sensitivity analysis indicated that no single nucleotide polymorphism(SNP) caused significant changes in overall causality.Bayesian model-averaged MR was also used to rank causality based on marginal inclusion probability (MIP),and the corresponding modelaveraged causal estimate (MACE) were confirmed,which indicated that WC (GWAS ID:ukb-b-9405)was the highest-ranked risk factor (MIP=0.119,MACE=0.011);its posterior probability was 0.057.A total of 14 sex-specific GWAS data on weight,BMI,and WC were analyzed in relationship with CA,and the MR results showed no significant effects of sex-specific factors.CONCLUSION:Body weight,BMI,and WC are causally associated with an increased risk of CA,with WC identified as the most important risk factor.展开更多
Site index(SI)is determined from the top height development and is a proxy for forest productivity,defined as the expected top height for a given species at a certain index age.In Norway,an index age of 40 years is us...Site index(SI)is determined from the top height development and is a proxy for forest productivity,defined as the expected top height for a given species at a certain index age.In Norway,an index age of 40 years is used.By using bi-temporal airborne laser scanning(ALS)data,SI can be determined using models estimated from SI observed on field plots(the direct approach)or from predicted top heights at two points in time(the height differential approach).Time series of ALS data may enhance SI determination compared to conventional methods used in operational forest inventory by providing more detailed information about the top height development.We used longitudinal data comprising spatially consistent field and ALS data collected from training plots in 1999,2010,and 2022 to determine SI using the direct and height differential approaches using all combinations of years and performed an external validation.We also evaluated the use of data assimilation.Values of root mean square error obtained from external validation were in the ranges of 16.3%–21.4%and 12.8%–20.6%of the mean fieldregistered SI for the direct approach and the height differential approach,respectively.There were no statistically significant effects of time series length or the number of points in time on the obtained accuracies.Data assimilation did not result in any substantial improvement in the obtained accuracies.Although a time series of ALS data did not yield greater accuracies compared to using only two points in time,a larger proportion of the study area could be used in ALS-based determination of SI when a time series was available.This was because areas that were unsuitable for SI determination between two points in time could be subject to SI determination based on data from another part of the time series.展开更多
The Wiener index of a graph is defined to be the sum of the distances of all pairs of vertices in the graph.The kth power G^(k) of a graph G is the graph on V(G)and two vertices are adjacent if and only if their dista...The Wiener index of a graph is defined to be the sum of the distances of all pairs of vertices in the graph.The kth power G^(k) of a graph G is the graph on V(G)and two vertices are adjacent if and only if their distance in G is less or equal to k.In this paper,we computed the Wiener index of the kth power of paths and cycles for any k≥2.展开更多
An assessment index system including environment, socio-culture, economy and technology was established for evaluating environmental construction level of community （objective construction）, and questionnaire was de...An assessment index system including environment, socio-culture, economy and technology was established for evaluating environmental construction level of community （objective construction）, and questionnaire was designed according to paper review for evaluating residential satisfaction （subjective satisfaction）. The index system was divided into four layers： system （A）, subsystems （B）, categories （C）, and indicators （D）, and in total of 38 indicators was established. The Xihe community, affiliated to Nanfen district, Benxi City, Liaoning Province, China was selected as a case study. Results indicated that the community sustainability index related to objective environmental construction was 0.4355 and was classified as class Ⅲ （moderate）; the community sustainability index related to the residential satisfaction was 0.4255, belonging to class Ⅲ. In conclusion, the sustainability of Xihe community was moderate and needed to be improved. Residential satisfaction was lower than objective environmental construction. The assessment index system established in this study is able to reflect the comprehensive sustainability of community and can be used to evaluate other similar communities＇ sustainability.展开更多
Regarding the complexity and inconsistency of results in existing evaluation methods of mine cooling system, this paper clarifies the advantages, disadvantages and application of various mine cooling sys- tems through...Regarding the complexity and inconsistency of results in existing evaluation methods of mine cooling system, this paper clarifies the advantages, disadvantages and application of various mine cooling sys- tems through principle analysis, and divides all the cooling systems into air-cooling, ice-cooling and water-cooling according to the transportation of cold energy. On this basis, the paper proposes a simple and efficient evaluation method for mine cooling system. The first index of this method is the air temper- ature at point C which is 15 m away from the return wind corner at working face. A cooling system will be judged ineligible if the air temperature at point C is above 30 ℃ during operation, because in this case, the combustible gases in coal will sharply overflow, inducing gas incidents. Based on the preliminary judg- ment of the first index, another two evaluation indexes are proposed based on the cooling ability and dehumidification of an airflow volume of 1000 m3/min at point C to evaluate the investment and opera- tion cost of mine cooling system. This evaluation method has already been successfully applied in the cooling system design of Zhangshuanglou coal mine.展开更多
This paper establishes a risk assessment index system for the natural gas industrial chain. China＇s natural gas industrial chain is entering a stage of rapid growth. In order to guarantee healthy development of the n...This paper establishes a risk assessment index system for the natural gas industrial chain. China＇s natural gas industrial chain is entering a stage of rapid growth. In order to guarantee healthy development of the natural gas industrial chain, it is urgent to establish a risk alert system, which is based on a risk assessment index system. First of all, the risks of the natural gas industrial chain are defined in the paper; then the risk factors are analyzed according to the present status of the natural gas industrial chain, and five categories of risk factors are summarized： resource risk, transport risk, marketing risk, risk of unbalanced chain links, and environment risk. The paper presents the principles of the risk assessment index system. The natural gas industrial chain risk assessment index system is established with four levels and forty-six risk indices.展开更多
With the ever-increased installed capacity of renewable energy generation units in a power system,the so-called shared energy storage(SES),a novel business model under the umbrella of the shared economy principle,has ...With the ever-increased installed capacity of renewable energy generation units in a power system,the so-called shared energy storage(SES),a novel business model under the umbrella of the shared economy principle,has the potential to play an essential role in the accommodation of renewable energy generation.However,unified evaluation standards and methods,which can help decision-makers analyze the performance of the SES market,are still not available.In this paper,an evaluation index system of the SES market is designed based on the trading rules of China’s Qinghai province and the structure-conduct-performance(SCP)analytical model.Moreover,the definition and characteristics of the indices,which can show the performance of the SES market from different perspectives,are given.Furthermore,the ideal cases are presented as the evaluation benchmark based on the development expectation of the SES market,and the analytic hierarchy process(AHP)and the technique for order preference by similarity to an ideal solution(TOPSIS)are applied to evaluate the SES market comprehensively.Finally,a case study based on actual data of the SES trading pilot project in Qinghai shows that the evaluation index system can reflect the operation status,existing problems and influencing factors of the SES market.展开更多
Dynamic resource allocation(DRA) is a key technology to improve system performances in GEO multi-beam satellite systems. And, since the cache resource on the satellite is very valuable and limited, DRA problem under r...Dynamic resource allocation(DRA) is a key technology to improve system performances in GEO multi-beam satellite systems. And, since the cache resource on the satellite is very valuable and limited, DRA problem under restricted cache resources is also an important issue to be studied. This paper mainly investigates the DRA problem of carrier resources under certain cache constraints. What's more, with the aim to satisfy all users' traffic demands as more as possible, and to maximize the utilization of the bandwidth, we formulate a multi-objective optimization problem(MOP) where the satisfaction index and the spectrum efficiency are jointly optimized. A modified strategy SA-NSGAII which combines simulated annealing(SA) and non-dominated sorted genetic algorithm-II(NSGAII) is proposed to approximate the Pareto solution to this MOP problem. Simulation results show the effectiveness of the proposed algorithm in terms of satisfaction index, spectrum efficiency, occupied cache, and etc.展开更多
A new method based on the combination of a neural network and a genetic algorithm was proposed to rank the order of exploitation priority of coalbed methane reservoirs. The neural network was used to acquire the weigh...A new method based on the combination of a neural network and a genetic algorithm was proposed to rank the order of exploitation priority of coalbed methane reservoirs. The neural network was used to acquire the weights of reservoir parameters through sample training and genetic algorithm was used to optimize the initial connection weights of nerve cells in case the neural network fell into a local minimum. Additionally, subordinate functions of each parameter were established to normalize the actual values of parameters of coalbed methane reservoirs in the range between zero and unity. Eventually, evaluation values of all coalbed methane reservoirs could be obtained by using the comprehensive evaluation method, which is the basis to rank the coalbed methane reservoirs in the order of exploitation priority. The greater the evaluation value, the higher the exploitation priority. The ranking method was verified in this paper by ten exploited coalbed methane reservoirs in China. The evaluation results are in agreement with the actual exploitation cases. The method can ensure the truthfulness and credibility of the weights of parameters and avoid the subjectivity caused by experts. Furthermore, the probability of falling into local minima is reduced, because genetic the algorithm is used to optimize the neural network system.展开更多
In this study, we developed a comprehensive index system for forestry sustainability of Heilongjiang Province, which includes forest resources sustainability,sustainable economic development, sustainable social develo...In this study, we developed a comprehensive index system for forestry sustainability of Heilongjiang Province, which includes forest resources sustainability,sustainable economic development, sustainable social development and sustainable advancement in science and technology. Based on this system and the regional forest development, we further evaluated the sustainability of Heilongjiang Province for year 2008-2013. The results show that even though the regional forestry has been preliminarily on the track of sustainable development, it is fragile. Four indicators, e.g. soil and water retention rate,forest stand growth（per unit area）, the proportion of national investment and the annual carbon sequestration have important impact on the sustainability, with a weight of 39.0 % in all the indicators. We also analyzed the factors hindering the sustainable development. It turns out that soil and water retention rate, forest stand growth（per unit area）,the proportion of science and technology funds, per capita GDP and the proportion of the tertiary industry production are the main factors hindering regional sustainable development, which accounts for 50.94 % of the total obstacle degrees in the system. At last, we discussed how to promote the regional sustainable development from the perspectives of forest resources sustainability, economic development sustainability, society development sustainability and the sustainable advancement of science and technology.展开更多
Plant flowering and breeding characteristics are important for us to understand the reproduction of plant populations. In this paper, we studied the reproduction characteristics of Jatropha curcas in Yuanjiang County ...Plant flowering and breeding characteristics are important for us to understand the reproduction of plant populations. In this paper, we studied the reproduction characteristics of Jatropha curcas in Yuanjiang County （23°36＇1＇4, 101°00＇E）, Yunnan Province. The plant produces flowers in dichasial inflorescences. Normally, the flowers are unisexual, and male and female flowers are produced in the same inflorescence. Only a few male flowers are produced in an inflorescence, and fruits are produced only through pollination between different flowers from the same or different plants. By the treatments of emasculation, bagging and artificial pollination in this experiment, there were few but same fruit set ratios when the inflorescences were emasculated, bagged, or bagged with net, except artificial pollination treatments, which showed that Jatropha curcas could produce fruit through apomixis but not wind pollination. When the inflorescences were unbagged, unemasculated and with free pollination treatments, or bagged, emasculated and with artificial cross-pollination treatments, or unbagged, emasculated and with free pollination treatments, there were many fruits produced. It showed that Jatropha curcas shows outcrossing, is self-compatible, and demanding for pollinators. Normally, the male flowers open first and a few flowers bloom in one day in a raceme. These flowers last a long time in bloom. However, a large number of female flowers open from the third to the fifth day, with some female flowers opening first in a few raceme. This shows a tendency to promote xenogamy and minimize geitonogamy.展开更多
Keerqin sand land is located in the transitional terrain between the Northeast Plain and Inner Mongolia （42°41′-45°15′N, 118°35′-123°30′ E） in Northeast China and it is seriously affected by ...Keerqin sand land is located in the transitional terrain between the Northeast Plain and Inner Mongolia （42°41′-45°15′N, 118°35′-123°30′ E） in Northeast China and it is seriously affected by desertification. According to the configuration and ecotope of the earths surface, the coverage of vegetation, occupation ratio of bare sandy land and the soil texture were selected as evaluation indexes by using the field investigation data. The evaluation index system of Keerqin sandy desertification was established by using Remote Sensing data. and the occupation ratio of bare sandy land was obtained by mixed spectrum model. This index system is validated by the field investioation data and results indicate that it is suitable for the desertification evaluation of Keerqin.Foundation Item： This study is supported by a grant from the National Natural Science Foundation of China （No. 30371192）展开更多
With the background of China's fast growing economy, Internet has become a key factor to keep the economy go steadily. It is important to quantitatively analyze the whole Internet industry and hence master its dev...With the background of China's fast growing economy, Internet has become a key factor to keep the economy go steadily. It is important to quantitatively analyze the whole Internet industry and hence master its development direction clearly, which will provide regulators with reference for industry analysis, policy formulation, and policy evaluation. This article re-constructs the calculation method of traditional Prosperity Indexes, and builds up a new indicators portfolio for Internet Industry Prosperity Indexes. By calculation, the Internet Industry Coincidence Index value is 105.9. And the Leading Index and Coincidence Index are all within the up-going range, which suggests that China's Internet Industry is likely to remain in its usual fast growing state.展开更多
The authors study the existence of solutions for the nonlinear elliptic system {-Mλ＋,（D2u）=f（u,v）in Ω,-Mλ＋,（D2u）=g（u,v）inΩ,u≥0,v≥0 inΩ,u=v=0 on Ω, where Ω is a bounded convex domain in RN, N ≥ 2. I...The authors study the existence of solutions for the nonlinear elliptic system {-Mλ＋,（D2u）=f（u,v）in Ω,-Mλ＋,（D2u）=g（u,v）inΩ,u≥0,v≥0 inΩ,u=v=0 on Ω, where Ω is a bounded convex domain in RN, N ≥ 2. It is shown that under some assumptions on f and g, the problem has at least one positive solution （u, v）.展开更多
基金Basic Research Spe-cial Project of Suzhou Science and Technology Bureau(SSD2024050).
文摘Objective Venous thromboembolism is a highly prevalent condition after polytrauma,and recognized as an important factor contributing to poor prognosis.The aim of this study was to investigate the risk factors for lower extremity deep venous thrombosis(LEDVT)in a severely traumatized population and to evaluate their predictive value for LEDVT.Methods This was a retrospective,single-center observational study.All subjects were severely traumatized patients who were admitted to the Traumatic Intensive Care Unit from January 2021 to May 2024.Based on Doppler ultrasound findings of both lower extremities from the time of injury to 30 days post-injury,patients who developed LEDVT were enrolled in the LEDVT group,and those who did not develop LEDVT were enrolled in the NLEDVT group.Demographic,clinical,and laboratory data were collected upon admission.Multivariable logistic regression analysis was performed to identify risk factors for LEDVT.Receiver operating characteristic(ROC)curve was used to evaluate the overall fit of the final model.Results There were 56 patients enrolled in the LEDVT group and 81 patients in the NLEDVT group.Age,Aggregate Index of Systemic Inflammation(AISI),Systemic Inflammation Response Index(SIRI),ICU length of stay,and albumin were identified as independent risk factors for LEDVT(all P<0.05).The area under their ROC curves were 0.604,0.657,0.694,0.668,and 0.405,respectively.Combined model for early clinical prediction of LEDVT in severely traumatized patients by age,SIRI,AISI,and albumin resulted in an area under the ROC curve of 0.805(95%CI:0.73-0.88,SE=0.037).Conclusion The combination of age,SIRI,AISI,and albumin has a predictive value for LEDVT in severely traumatized patients.
基金State Grid Jibei Electric Power Company Limited(no.SGJBJY00GPJS2310051)Natural Science Foundation of Beijing Municipality(no.9242015).
文摘Because of the contradiction between the scale of new energy installations and the continuous load growth in the central and eastern regions of China,the balance problems of the electricity market are becoming increasingly prominent,and it is urgent to solve such problems through inter-provincial electricity spot markets.First,the development history and construction status of the inter-provincial electricity spot market are summarized;second,the mechanism design of the inter-provincial electricity spot market is sorted out in terms of the market operation framework,transaction declaration,and clearing methods;subsequently,the evaluation index system of the inter-provincial electricity spot market is constructed,including four themes of electricity mutual aid and support,new energy consumption,economic benefits of market-based allocation,and social benefits of market-based allocation;finally,the operation of the inter-provincial electricity spot market is comprehensively analyzed by the algorithm based on the market operation data of 2022,which proves the feasibility and practicality of the proposed index system.
基金financially supported by the Sichuan Science and Technology Program (Grant No. 2023ZYD0158)the National Natural Science Foundation of China (Grant Nos. 42304147 and 42304076)。
文摘The main objective is to optimize the development of shale gas-rich areas by predicting seismic sweet spot parameters in shale reservoirs. We systematically assessed the fracture development, fracture gas content, and rock brittleness in fractured gas-bearing shale reservoirs. To better characterize gas-bearing shale reservoirs with tilted fractures, we optimized the petrophysical modeling based on the equivalent medium theory. Based on the advantages of shale petrophysical modeling, we not only considered the brittle mineral fraction but also the combined effect of shale porosity, gas saturation, and total organic carbon(TOC) when optimizing the brittleness index. Due to fractures generally functioning as essential channels for fluid storage and movement, fracture density and fracture fluid identification factors are critical geophysical parameters for fractured reservoir prediction. We defined a new fracture gas indication factor(GFI) to detect fracture-effective gas content. A new linear PP-wave reflection coefficient equation for a tilted transversely isotropic(TTI) medium was rederived, realizing the direct prediction of anisotropic fracture parameters and the isotropic elasticity parameters from offset vector tile(OVT)-domain seismic data. Synthetic seismic data experiments demonstrated that the inversion algorithm based on the L_P quasinorm sparsity constraint and the split-component inversion strategy exhibits high stability and noise resistance. Finally, we applied our new prediction method to evaluate fractured gas-bearing shale reservoirs in the Sichuan Basin of China, demonstrating its effectiveness.
文摘The effect of inhaled nano-TiO2 on lung histology and serum biochemical indexes is evaluated in healthy and adult Kunming mice（eight in each group）after exposure to TiO2 aerosols（1 500 mg/m3）in a sealed chamber.Another eight mice are exposed to indoor air to be served as a control group.Lung tissue and blood are collected after euthanizing the animals.The results show that lactate dehydrogenase（LDH）activity increases in all experimental groups.Alanine aminotransferase（ALT）activity and blood urea nitrogen（BUN）levels are increased in the group exposed to TiO2 aerosols for 28 d,and creatinine（Cr）levels are increased in 14 d and 28 d samples（P0.05）.No obvious changes are observed in other serum indexes.Lungs of mice exposed to 28 d exposure show significant but moderate increase in pulmonary inflammation,and many TiO2 particles are found in the interstitium of pulmonary alveoli.
基金Supported by the National 863 Plan Foundation under Grant No.2003AA414060
文摘In the process of designing self-elevating drilling unit, it is important, yet complicated, to use comparison and filtering to select the optimum scheme from the feasible ones. In this research, an index system and methodology for the evaluation of self-elevating drilling unit was proposed. Based on this, a multi-objective combinatorial optimization model was developed, using the improved grey relation Analysis （GRA）, in which the analytic hierarchy process （AHP） was used to determine the weights of the evaluating indices. It considered the connections within the indices, reflecting the objective nature of things, and also considered the subjective interests of ship owners and the needs of designers. The evaluation index system and evaluation method can be used in the selection of an optimal scheme and advanced assessment. A case study shows the index system and evaluation method are scientific, reasonable, and easy to put into practice. At the same time, such an evaluation index system and evaluation method will be helpful for making decisions for other mobile platforms.
基金supported by the National Natural Science Foundation of China(No.31988102)Yunnan Province Major Program for Basic Research Project(No.202101BC070002)+1 种基金Yunnan Province Science and Technology Talents and Platform Program(No.202305AA160014)Yunnan Province Key Research and Development Program of China(No.202303AC100009)。
文摘Forest structure is fundamental in determining ecosystem function,yet the impact of bamboo invasion on these structural characteristics remains unclear.We investigated 219 invasion transects at 41 sites across the distribution areas of Moso bamboo(Phyllostachys edulis)in China to explore the effects of bamboo invasion on forest structural attributes and diameter–height allometries by comparing paired plots of bamboo,mixed bamboo-tree,and non-bamboo forests along the transects.We found that bamboo invasion decreased the mean and maximum diameter at breast height,maximum height,and total basal area,but increased the mean height,stem density,and scaling exponent for stands.Bamboo also had a higher scaling exponent than tree,particularly in mixed forests,suggesting a greater allocation of biomass to height growth.As invasion intensity increased,bamboo allometry became more plastic and decreased significantly,whereas tree allometry was indirectly promoted by increasing stem density.Additionally,a humid climate may favour the scaling exponents for both bamboo and tree,with only minor contributions from topsoil moisture and nitrogen content.The inherent superiority of diameter–height allometry allows bamboo to outcompete tree and contributes to its invasive success.Our findings provide a theoretical basis for understanding the causes and consequences of bamboo invasion.
基金This study is supported by the National Natural Science Foundation of China (No. 82072127)。
文摘BACKGROUND:This study aims to explore the causal relationship of body weight,body mass index(BMI),and waist circumference (WC) with the risk of cardiac arrest (CA) using two-sample Mendelian randomization (MR).METHODS:Data were summarized using genome-wide association studies (GWAS).Twosample MR analyses were performed using the inverse variance weighting (IVW) method,the weighted median method,and the MR-Egger analysis.Heterogeneity test and sensitivity analysis were performed using Cochran’s Q test and the leave-one-out method,respectively.The Steiger test was used to detect reverse causality.Bayesian model-averaged MR was used to identify the most influential risk factors.RESULTS:A total of 13 GWAS data were collected for BMI,body weight and WC.IVW analyses showed a positive correlation of body weight,BMI,and WC with CA (all OR>1 and P<0.05),with MR-Egger and weighted median methods confirming the IVW findings.No horizontal pleiotropy or heterogeneity was observed.Sensitivity analysis indicated that no single nucleotide polymorphism(SNP) caused significant changes in overall causality.Bayesian model-averaged MR was also used to rank causality based on marginal inclusion probability (MIP),and the corresponding modelaveraged causal estimate (MACE) were confirmed,which indicated that WC (GWAS ID:ukb-b-9405)was the highest-ranked risk factor (MIP=0.119,MACE=0.011);its posterior probability was 0.057.A total of 14 sex-specific GWAS data on weight,BMI,and WC were analyzed in relationship with CA,and the MR results showed no significant effects of sex-specific factors.CONCLUSION:Body weight,BMI,and WC are causally associated with an increased risk of CA,with WC identified as the most important risk factor.
基金part of the Centre for Research-based Innovation SmartForest:Bringing Industry 4.0 to the Norwegian forest sector(NFR SFI project no.309671,smartforest.no)。
文摘Site index(SI)is determined from the top height development and is a proxy for forest productivity,defined as the expected top height for a given species at a certain index age.In Norway,an index age of 40 years is used.By using bi-temporal airborne laser scanning(ALS)data,SI can be determined using models estimated from SI observed on field plots(the direct approach)or from predicted top heights at two points in time(the height differential approach).Time series of ALS data may enhance SI determination compared to conventional methods used in operational forest inventory by providing more detailed information about the top height development.We used longitudinal data comprising spatially consistent field and ALS data collected from training plots in 1999,2010,and 2022 to determine SI using the direct and height differential approaches using all combinations of years and performed an external validation.We also evaluated the use of data assimilation.Values of root mean square error obtained from external validation were in the ranges of 16.3%–21.4%and 12.8%–20.6%of the mean fieldregistered SI for the direct approach and the height differential approach,respectively.There were no statistically significant effects of time series length or the number of points in time on the obtained accuracies.Data assimilation did not result in any substantial improvement in the obtained accuracies.Although a time series of ALS data did not yield greater accuracies compared to using only two points in time,a larger proportion of the study area could be used in ALS-based determination of SI when a time series was available.This was because areas that were unsuitable for SI determination between two points in time could be subject to SI determination based on data from another part of the time series.
基金Supported by National Natural Science Foundation of China(Grant No.12201471)the Special Foundation in Key Fields for Universities of Guangdong Province(Grant No.2022ZDZX1034).
文摘The Wiener index of a graph is defined to be the sum of the distances of all pairs of vertices in the graph.The kth power G^(k) of a graph G is the graph on V(G)and two vertices are adjacent if and only if their distance in G is less or equal to k.In this paper,we computed the Wiener index of the kth power of paths and cycles for any k≥2.
基金This study was supported by the National Key Tech-nologies R & D Program of China (2006BAD03A09)Agrifund of China’s Ministry of Science and Technology (2006GB24910472)
文摘An assessment index system including environment, socio-culture, economy and technology was established for evaluating environmental construction level of community （objective construction）, and questionnaire was designed according to paper review for evaluating residential satisfaction （subjective satisfaction）. The index system was divided into four layers： system （A）, subsystems （B）, categories （C）, and indicators （D）, and in total of 38 indicators was established. The Xihe community, affiliated to Nanfen district, Benxi City, Liaoning Province, China was selected as a case study. Results indicated that the community sustainability index related to objective environmental construction was 0.4355 and was classified as class Ⅲ （moderate）; the community sustainability index related to the residential satisfaction was 0.4255, belonging to class Ⅲ. In conclusion, the sustainability of Xihe community was moderate and needed to be improved. Residential satisfaction was lower than objective environmental construction. The assessment index system established in this study is able to reflect the comprehensive sustainability of community and can be used to evaluate other similar communities＇ sustainability.
基金supported by the key project of National Natural Science Foundation ‘‘Deep Heat Governance and Utilization’’ (Nos.51134005 and 41402273)the Doctoral Fund of Ministry of Education (No. 20130023110021)
文摘Regarding the complexity and inconsistency of results in existing evaluation methods of mine cooling system, this paper clarifies the advantages, disadvantages and application of various mine cooling sys- tems through principle analysis, and divides all the cooling systems into air-cooling, ice-cooling and water-cooling according to the transportation of cold energy. On this basis, the paper proposes a simple and efficient evaluation method for mine cooling system. The first index of this method is the air temper- ature at point C which is 15 m away from the return wind corner at working face. A cooling system will be judged ineligible if the air temperature at point C is above 30 ℃ during operation, because in this case, the combustible gases in coal will sharply overflow, inducing gas incidents. Based on the preliminary judg- ment of the first index, another two evaluation indexes are proposed based on the cooling ability and dehumidification of an airflow volume of 1000 m3/min at point C to evaluate the investment and opera- tion cost of mine cooling system. This evaluation method has already been successfully applied in the cooling system design of Zhangshuanglou coal mine.
基金This research is supported by CNPC Innovation Foundation.
文摘This paper establishes a risk assessment index system for the natural gas industrial chain. China＇s natural gas industrial chain is entering a stage of rapid growth. In order to guarantee healthy development of the natural gas industrial chain, it is urgent to establish a risk alert system, which is based on a risk assessment index system. First of all, the risks of the natural gas industrial chain are defined in the paper; then the risk factors are analyzed according to the present status of the natural gas industrial chain, and five categories of risk factors are summarized： resource risk, transport risk, marketing risk, risk of unbalanced chain links, and environment risk. The paper presents the principles of the risk assessment index system. The natural gas industrial chain risk assessment index system is established with four levels and forty-six risk indices.
基金supported by the Science and Technology Project of State Grid Qinghai Electric Power Company(No.106000003367).
文摘With the ever-increased installed capacity of renewable energy generation units in a power system,the so-called shared energy storage(SES),a novel business model under the umbrella of the shared economy principle,has the potential to play an essential role in the accommodation of renewable energy generation.However,unified evaluation standards and methods,which can help decision-makers analyze the performance of the SES market,are still not available.In this paper,an evaluation index system of the SES market is designed based on the trading rules of China’s Qinghai province and the structure-conduct-performance(SCP)analytical model.Moreover,the definition and characteristics of the indices,which can show the performance of the SES market from different perspectives,are given.Furthermore,the ideal cases are presented as the evaluation benchmark based on the development expectation of the SES market,and the analytic hierarchy process(AHP)and the technique for order preference by similarity to an ideal solution(TOPSIS)are applied to evaluate the SES market comprehensively.Finally,a case study based on actual data of the SES trading pilot project in Qinghai shows that the evaluation index system can reflect the operation status,existing problems and influencing factors of the SES market.
基金supported by the National Science and Technology Major Project under Grant 2018ZX03001016
文摘Dynamic resource allocation(DRA) is a key technology to improve system performances in GEO multi-beam satellite systems. And, since the cache resource on the satellite is very valuable and limited, DRA problem under restricted cache resources is also an important issue to be studied. This paper mainly investigates the DRA problem of carrier resources under certain cache constraints. What's more, with the aim to satisfy all users' traffic demands as more as possible, and to maximize the utilization of the bandwidth, we formulate a multi-objective optimization problem(MOP) where the satisfaction index and the spectrum efficiency are jointly optimized. A modified strategy SA-NSGAII which combines simulated annealing(SA) and non-dominated sorted genetic algorithm-II(NSGAII) is proposed to approximate the Pareto solution to this MOP problem. Simulation results show the effectiveness of the proposed algorithm in terms of satisfaction index, spectrum efficiency, occupied cache, and etc.
基金EU-China Energy and Environment Programme(Europe Aid/120723/D/SV/CN)Research Fund for the Doctoral Program of Higher Education of China(20030425001)
文摘A new method based on the combination of a neural network and a genetic algorithm was proposed to rank the order of exploitation priority of coalbed methane reservoirs. The neural network was used to acquire the weights of reservoir parameters through sample training and genetic algorithm was used to optimize the initial connection weights of nerve cells in case the neural network fell into a local minimum. Additionally, subordinate functions of each parameter were established to normalize the actual values of parameters of coalbed methane reservoirs in the range between zero and unity. Eventually, evaluation values of all coalbed methane reservoirs could be obtained by using the comprehensive evaluation method, which is the basis to rank the coalbed methane reservoirs in the order of exploitation priority. The greater the evaluation value, the higher the exploitation priority. The ranking method was verified in this paper by ten exploited coalbed methane reservoirs in China. The evaluation results are in agreement with the actual exploitation cases. The method can ensure the truthfulness and credibility of the weights of parameters and avoid the subjectivity caused by experts. Furthermore, the probability of falling into local minima is reduced, because genetic the algorithm is used to optimize the neural network system.
文摘In this study, we developed a comprehensive index system for forestry sustainability of Heilongjiang Province, which includes forest resources sustainability,sustainable economic development, sustainable social development and sustainable advancement in science and technology. Based on this system and the regional forest development, we further evaluated the sustainability of Heilongjiang Province for year 2008-2013. The results show that even though the regional forestry has been preliminarily on the track of sustainable development, it is fragile. Four indicators, e.g. soil and water retention rate,forest stand growth（per unit area）, the proportion of national investment and the annual carbon sequestration have important impact on the sustainability, with a weight of 39.0 % in all the indicators. We also analyzed the factors hindering the sustainable development. It turns out that soil and water retention rate, forest stand growth（per unit area）,the proportion of science and technology funds, per capita GDP and the proportion of the tertiary industry production are the main factors hindering regional sustainable development, which accounts for 50.94 % of the total obstacle degrees in the system. At last, we discussed how to promote the regional sustainable development from the perspectives of forest resources sustainability, economic development sustainability, society development sustainability and the sustainable advancement of science and technology.
文摘Plant flowering and breeding characteristics are important for us to understand the reproduction of plant populations. In this paper, we studied the reproduction characteristics of Jatropha curcas in Yuanjiang County （23°36＇1＇4, 101°00＇E）, Yunnan Province. The plant produces flowers in dichasial inflorescences. Normally, the flowers are unisexual, and male and female flowers are produced in the same inflorescence. Only a few male flowers are produced in an inflorescence, and fruits are produced only through pollination between different flowers from the same or different plants. By the treatments of emasculation, bagging and artificial pollination in this experiment, there were few but same fruit set ratios when the inflorescences were emasculated, bagged, or bagged with net, except artificial pollination treatments, which showed that Jatropha curcas could produce fruit through apomixis but not wind pollination. When the inflorescences were unbagged, unemasculated and with free pollination treatments, or bagged, emasculated and with artificial cross-pollination treatments, or unbagged, emasculated and with free pollination treatments, there were many fruits produced. It showed that Jatropha curcas shows outcrossing, is self-compatible, and demanding for pollinators. Normally, the male flowers open first and a few flowers bloom in one day in a raceme. These flowers last a long time in bloom. However, a large number of female flowers open from the third to the fifth day, with some female flowers opening first in a few raceme. This shows a tendency to promote xenogamy and minimize geitonogamy.
基金This study is supported by a grant from the National Natural Science Foundation of China （No. 30371192）
文摘Keerqin sand land is located in the transitional terrain between the Northeast Plain and Inner Mongolia （42°41′-45°15′N, 118°35′-123°30′ E） in Northeast China and it is seriously affected by desertification. According to the configuration and ecotope of the earths surface, the coverage of vegetation, occupation ratio of bare sandy land and the soil texture were selected as evaluation indexes by using the field investigation data. The evaluation index system of Keerqin sandy desertification was established by using Remote Sensing data. and the occupation ratio of bare sandy land was obtained by mixed spectrum model. This index system is validated by the field investioation data and results indicate that it is suitable for the desertification evaluation of Keerqin.Foundation Item： This study is supported by a grant from the National Natural Science Foundation of China （No. 30371192）
文摘With the background of China's fast growing economy, Internet has become a key factor to keep the economy go steadily. It is important to quantitatively analyze the whole Internet industry and hence master its development direction clearly, which will provide regulators with reference for industry analysis, policy formulation, and policy evaluation. This article re-constructs the calculation method of traditional Prosperity Indexes, and builds up a new indicators portfolio for Internet Industry Prosperity Indexes. By calculation, the Internet Industry Coincidence Index value is 105.9. And the Leading Index and Coincidence Index are all within the up-going range, which suggests that China's Internet Industry is likely to remain in its usual fast growing state.
基金supported by National Natural Sciences Foundations of China (10571175,10631030)
文摘The authors study the existence of solutions for the nonlinear elliptic system {-Mλ＋,（D2u）=f（u,v）in Ω,-Mλ＋,（D2u）=g（u,v）inΩ,u≥0,v≥0 inΩ,u=v=0 on Ω, where Ω is a bounded convex domain in RN, N ≥ 2. It is shown that under some assumptions on f and g, the problem has at least one positive solution （u, v）.
