Ocean energy has progressively gained considerable interest due to its sufficient potential to meet the world’s energy demand,and the blade is the core component in electricity generation from the ocean current.Howev...Ocean energy has progressively gained considerable interest due to its sufficient potential to meet the world’s energy demand,and the blade is the core component in electricity generation from the ocean current.However,the widened hydraulic excitation frequency may satisfy the blade resonance due to the time variation in the velocity and angle of attack of the ocean current,even resulting in blade fatigue and destructively interfering with grid stability.A key parameter that determines the resonance amplitude of the blade is the hydrodynamic damping ratio(HDR).However,HDR is difficult to obtain due to the complex fluid-structure interaction(FSI).Therefore,a literature review was conducted on the hydrodynamic damping characteristics of blade-like structures.The experimental and simulation methods used to identify and obtain the HDR quantitatively were described,placing emphasis on the experimental processes and simulation setups.Moreover,the accuracy and efficiency of different simulation methods were compared,and the modal work approach was recommended.The effects of key typical parameters,including flow velocity,angle of attack,gap,rotational speed,and cavitation,on the HDR were then summarized,and the suggestions on operating conditions were presented from the perspective of increasing the HDR.Subsequently,considering multiple flow parameters,several theoretical derivations and semi-empirical prediction formulas for HDR were introduced,and the accuracy and application were discussed.Based on the shortcomings of the existing research,the direction of future research was finally determined.The current work offers a clear understanding of the HDR of blade-like structures,which could improve the evaluation accuracy of flow-induced vibration in the design stage.展开更多
Foreign language teaching has shifted from teacher-centered teaching method to student-centered in recent years.Affective factors should be paid enough attention in teacher-learner interaction in.This paper aims to ma...Foreign language teaching has shifted from teacher-centered teaching method to student-centered in recent years.Affective factors should be paid enough attention in teacher-learner interaction in.This paper aims to make an exploration into the effects of affective factors in college learners'classroom.展开更多
Analyses the learners'linguistic environment,language,and the age which have made specific influence on the second language acquisition.These factors play a crucial influence on the second language acquisition,tho...Analyses the learners'linguistic environment,language,and the age which have made specific influence on the second language acquisition.These factors play a crucial influence on the second language acquisition,though some researchers hold different opinions about influence of categories and degree.展开更多
Background High-risk infants refer to newborns exposed to high-risk factors in the prenatal, natal or postnatal period. High-risk infants are at high risk of developmental retardation, and early identification of deve...Background High-risk infants refer to newborns exposed to high-risk factors in the prenatal, natal or postnatal period. High-risk infants are at high risk of developmental retardation, and early identification of developmental abnormalities plays a vital role in improving high-risk infants' quality of life.Aims To describe the neurodevelopment of high-risk infants aged less than 1 year old, and to analyse the incidences and influencing factors of neurodevelopmental abnormalities in order to provide a basis for neurodevelopment monitoring and management of highrisk infants.Methods High-risk infants born between January 2016 and December 2016 in the maternity and infant health hospitals of three districts in Shanghai were followed up.The Gesell Developmental Scale was used to assess the neurodevelopmental level at the time of recruitment(0-2 months) and at 9 months. Univariate and multivariate analyses of the influencing factors were conducted.Results 484 high-risk infants(male 51 %, female 49%)with an average gestation age of 36.5±2.2 weeks were recruited. At the time of recruitment, the average age was2.1(0.8) months, and the developmental quotient(DQ)scores of full-term high-risk infants in motor(t=3.542,p=0.001), cognitive(t=3.125, p=0.002), language(t=3.189, p=0.002) and social(t=3.316, p=0.001) areas were higher than those of preterm infants. The incidences of developmental abnormalities of full-term high-risk infants in motor(χ~2 =9.452, p=0.002), cognitive(χ~2=6.258, p=0.012), language(χ~2 =12.319, p =0.001) and social(χ~2 =6.811, p=0.009) areas were lower than the preterm infants. At 9 months, there was no difference in the DQ scores and incidences of developmental abnormalities in four areas between full-term and preterm high-risk infants, and the incidence of developmental abnormalities was around 10%.Conclusion The incidence of neurodevelopmental abnormalities in high-risk infants aged less than 1 year old is high. Preterm birth and parental bad habits are significant factors affecting the neurodevelopment.Monitoring and early interventions help to improve highrisk infants' neurodevelopment.展开更多
By analyzing the importance of influencing factors and conducting a comparative study of the effects of different sorting algorithms, a new method is proposed that is suitable for classifying the growth state of a nat...By analyzing the importance of influencing factors and conducting a comparative study of the effects of different sorting algorithms, a new method is proposed that is suitable for classifying the growth state of a natural Metasequoia glyptostroboides Hu and W.C. Cheng population. We studied 2817 M. glyptostroboides trees over 100 years old and analyzed their growth state by measuring 15 factors from stumpage, site condition, and environmental data. The dimensionality of all factors were reduced using the random forest algorithm, and we classified the remaining factors using the following algorithms: random forest, back-propagation(BP) neural networks, and support vector machine(SVM). The applicability of each sorting algorithm was analyzed. When all the d factors are used for classification and modeling, the model's overall accuracy,kappa coefficient and test accuracy were 85.5%, 0.739 and 85.8%, respectively. By reducing the dimensionality of the factors using the random forest algorithm, 11 factors most strongly influenced the classifications of the growth state of the Metasequoia population: diameter at breast height,height, crown width, age from stumpage data; longitude,latitude, elevation, slope aspect, gradient and slope position from the site condition data; and the edge of the field from the environmental data. For classifying the Metasequoia population, the random forest algorithm has the highest overall accuracy at 87.2%, which is 3.4 and 2.3% higher than the BP neural networks and SVM algorithms,respectively. The SVM algorithm is superior to the random forest algorithm with respect to classifying the state of mortality. The combination of the random forest and SVM algorithms and their combined information can be used to classify and predict the growth state of this natural M.glyptostroboides population to provide a scientific basis for its effective protection.展开更多
Objective To investigate the influencing factors for prehospital delay in patients with acute myocardial infarction (AMI). Methods A total of 807 consecutive patients with AMI who presented to the emergency department...Objective To investigate the influencing factors for prehospital delay in patients with acute myocardial infarction (AMI). Methods A total of 807 consecutive patients with AMI who presented to the emergency department of Beijing Anzhen Hospital were analyzed. The influence of several potential risk factors on the prehospital delay time (PDT) was evaluated by comparing patients admitted more than 2 hours after onset of chese pain with those admitted within 2 hours after onset. Results Among 807 patients, 402 came to the hospital within 2 hours while the others arrived at the hospital after 2 hours. The median PDT was 130 min. Among the potential variables, advanced age, history of diabetes mellitus, occurrence of symptom at night and use of emergency medical service significantly affected PDT by multivariate analysis. Conclusion Interventions aimed at reducing the prehospital delay in AMI should primarily focus on the awareness of the risk and help-seeking behavior of patients.展开更多
This study aims at identifying crash-influencing factors by facility type of Nagoya Urban Expressway, considering the interaction of geometry, traffic flow, and ambient conditions. Crash rate （CR） model is firstly d...This study aims at identifying crash-influencing factors by facility type of Nagoya Urban Expressway, considering the interaction of geometry, traffic flow, and ambient conditions. Crash rate （CR） model is firstly developed separately at four facility types： basic, merge, and diverge segments and sharp curve. Traffic flows are thereby categorized, and based on the traffic categories, the significances of factors affecting crashes are analyzed by principal component analysis. The results reveal that, the CR at merge segment is significantly higher than those at basic and diverge segments in uncongested flow, while the value is not significantly different at the three facility types in congested flow. In both un- and congested flows, sharp curve has the worst safety performance in view of its highest CR. Regarding influencing factors, geometric design and traffic flow are most significant in un- and congested flows, respectively. As mainline flow increases, the effect of merging ratio affecting crash is on the rise at basic and merge segments as opposed to the decreasing significance of diverging ratio at diverge segment. Mean- while, longer acceleration and deceleration lanes are adverse to safety in uncongested flow, while shorter acceleration and deceleration lanes are adverse in congested flow. Due to its special geometric design, crashes at sharp curve are highly associated with the large centrifugal force and heavy restricted visibility.展开更多
To exert the imbibition between cracks and matrix effectively and enhance the development effect of tight oil reservoirs, a physical simulation method for imbibition in different scales of cores is developed by combin...To exert the imbibition between cracks and matrix effectively and enhance the development effect of tight oil reservoirs, a physical simulation method for imbibition in different scales of cores is developed by combining a high-pressure large-model physical simulation system and nuclear magnetic resonance technology(NMR) to investigate the influencing factors of imbibition process in tight reservoirs, and construct a quantitative evaluation method for the imbibition in water flooding. The results show that in the process of counter-current imbibition, the lower the permeability, the later the oil droplet precipitation, the longer the imbibition equilibrium time, and the lower the recovery degree. Fractures can effectively expand the area of imbibition and the front edge of imbibition in the contact between the dense matrix and water, reduce the resistance of oil discharge, and improve the imbibition speed and the degree of recovery. The more hydrophilic the rock, the higher the imbibition rate and imbibition recovery of tight rocks. In the process of co-current imbibition, the lower the permeability, the more obvious the imbibition, and the displacement recovery is positively correlated with permeability, while the imbibition recovery is negatively correlated with the permeability. It also shows that the imbibition distance of the cyclic water injection is greater than that of the counter-current imbibition, and the higher the permeability and the injection multiple, the longer the imbibition distance. The combination of large-scale volume fracturing with changing reservoir wettability and cyclic water injection is conducive to improving the imbibition ability of tight reservoirs.展开更多
Henry Hub as an important transaction hub for natural gas sets the gas price standard in the USA. In this paper, the factors influencing Henry Hub natural gas prices are analyzed, and the major factors determining the...Henry Hub as an important transaction hub for natural gas sets the gas price standard in the USA. In this paper, the factors influencing Henry Hub natural gas prices are analyzed, and the major factors determining the price levels in the period between January 1997 and December 2016 are studied. It is found that economic conditions, total energy demand, US dollar exchange rate and gas consumption are the major factors. The mechanism of each factor influencing the Henry Hub natural gas price is also explored in the paper.展开更多
The main mechanical properties of scrimber and Parallel Strand Lumber (PSL) were researched through techno-logical test. Experimental materials of scrimber are small log of Aspen, Dahurian larch and Birch. Experimenta...The main mechanical properties of scrimber and Parallel Strand Lumber (PSL) were researched through techno-logical test. Experimental materials of scrimber are small log of Aspen, Dahurian larch and Birch. Experimental materials of PSL come from fishtail veneer strips at plywood plant of Aspen and Birch. In the laboratory conditions low quality small log and wood residues can yield scrimber and PSL with high strength. After the technological conditions of scrimber were compared with that of PSL, the main factors of influencing their properties were separately pointed out and the reasons influencing proper-ties have been analyzed in this paper. The results showed that the hot-pressing pressure is an important technological factor for scrimber. The ratio of veneer-strand length to thickness is a key technological factor for PSL.展开更多
Fluorescent in situ hybridization (FISH) was applied to investigate the phylogenetic relationship among Dendranthema spp. Genomic DNA of wild species which was used as probe did not give specific signals, while 18S-26...Fluorescent in situ hybridization (FISH) was applied to investigate the phylogenetic relationship among Dendranthema spp. Genomic DNA of wild species which was used as probe did not give specific signals, while 18S-26S rDNA from Arabidopsis, which was used as control probe, showed the loci on the target chromosomes clearly. Satisfied results of FISH were gotten when denaturing digoxingenen-labeled probe and chromosome together in oven at 80℃ for 1015min. There is little influence on the result by the stringency of washing when rDNA was used as probe. The result also indicates the limitation of genomic in situ hybridization (GISH) when used as an approach to analyze the phylogenetic relationship among Dendranthema spp. and the origin of cultivated chrysanthemum.展开更多
ASP-foam （ASPF） is a system prepared by injecting natural gas into the conventional alkali- surfactant-polymer （ASP） system. Foam can be formed in the porous media by the interaction of gas and surfactant in the A...ASP-foam （ASPF） is a system prepared by injecting natural gas into the conventional alkali- surfactant-polymer （ASP） system. Foam can be formed in the porous media by the interaction of gas and surfactant in the ASP system. With the ASPF system, oil recovery is improved as the interfacial tension （IFT） is reduced to a relatively low level, and the swept volume is enlarged. In this paper, four surfactants were evaluated and characterized by IFT between ASP system and oil and the foaming performance. AI- kyl benzene sulfonate （ORS-41） was chosen as the surfactant to best reduce IFT between displacement fluids and oil and improve the foaming performance. The mechanisms of ASPF flooding were studied in this paper, the results show that the ASPF flooding not only enlarges the swept volume but also enhances the displacement efficiency. The effects of reservoir heterogeneity, the gas-liquid ratio of ASPF system, and the concentrations of polymer and surfactant on the displacement efficiency were studied. A field trial of ASPF flooding has also been conducted. Both the laboratory results and the field trial results show that the ASPF flooding can significantly increase the oil recovery, with a 30% increase in the proportion of the original oil in place recovered compared with water flooding.展开更多
In this study, the main factors influencing the measurements by means of the off-line low-field 1H NMR in the lab were discussed base on a robust calibration model established by the PLS algorithm using 255 crude oil ...In this study, the main factors influencing the measurements by means of the off-line low-field 1H NMR in the lab were discussed base on a robust calibration model established by the PLS algorithm using 255 crude oil samples. The preheating temperature had a great influence on the viscosity of oil samples and the resolution of spectral analysis. The repeatability of spectral measurements was impacted by the metal and wax content of the oil samples. For the case of high wax content oils, the wax species began to crystallize in the course of determination that could affect the repeatability of spectral measurements. These factors have evidenced why the preheating devices and filter unit are necessary when low field NMR system is used in the online analysis process. The investigation is very important for the on-line application of the low field NMR.展开更多
To analyze the positive influencing factors of Chinese telecom operators' EVA(Economic Value Added),this paper selects fifteen indicators based on the enterprise features of telecom operators and telecommunication...To analyze the positive influencing factors of Chinese telecom operators' EVA(Economic Value Added),this paper selects fifteen indicators based on the enterprise features of telecom operators and telecommunications industry characteristics,and then classifies these indicators into the following factors:operation scale,profitability,solvency and asset management ability by factor analysis.This paper also gives the priorities of these four factors by regression analysis,of which the operation scale is the most important factor.The research results point out a clear method for the telecom operatorsto increase their EVA in order to meet the performance appraisal from State-owned Assets Supervision and Administration Commission of the State Council.展开更多
The homogeneous dielectric barrier discharge （DBD） in atmospheric air between two symmetric-columnar copper electrodes with epoxy plates as the dielectric barriers is generated using a us pulse high voltage power su...The homogeneous dielectric barrier discharge （DBD） in atmospheric air between two symmetric-columnar copper electrodes with epoxy plates as the dielectric barriers is generated using a us pulse high voltage power supply. The discharge characteristics are studied by measurement of its electrical discharge parameters and observation of its light emission phenom- ena, and the main discharge parameters of the homogenous DBD, such as discharge current and average discharge power, are calculated. Results show that the discharge generated is a homogeneous one with one larger single current pulse of about 2 #s duration appearing in each voltage pulse, and its light emission is radially homogeneous and covers the entire surface of the two elec- trodes. The influences of applied voltage amplitude, air gap distance and barrier thickness on the transition of discharge modes are studied. With the increase of air gap distance, the discharge will transit from homogeneous mode to filamentary mode. The higher the thickness of dielectric barriers, the larger the air gap distance for generating the homogeneous discharge mode. The average discharge power increases non-linearly with increasing applied voltage amplitude, and decreases non-linearly with the increase of air gap distance and barrier thickness. In order to generate stable and homogeneous DBD with high discharge power, thin barriers distance should be used, and higher applied voltage amplitude should be applied to small air gap.展开更多
Objective To investigate the association between preoperative,operative,and postoperative factors and persistent pleural effusion after the extracardiac Fontan procedure. Methods Ninety-five consecutive patients diagn...Objective To investigate the association between preoperative,operative,and postoperative factors and persistent pleural effusion after the extracardiac Fontan procedure. Methods Ninety-five consecutive patients diagnosed with univentricular heart underwent extracardiac connection using Gore-Tax conduits at the Department of Children’s Heart Centre,Justus-Liebig-University Giessen in Germany from June 1996 to July 2007. The outcome measures were duration and volume of chest tube drainage after surgical intervention. The investigated factors included age and weight at the time of operation,anatomical diagnosis,preoperative oxygen saturation,mean pulmonary artery pressure,ventricular end-diastolic pressure,fenestration,cardiopulmonary bypass time,conduit size,postoperative pulmonary artery pressure,administration of angiotensin-converting enzyme inhibitors,and postoperative infection. Associations between these factors and persistent pleural effusion after the extracardiac Fontan procedure were analyzed. Results Every patient suffered postoperative effusion. The median duration of postoperative chest tube drainage was 9 days (range,3-69 days),and the median volume was 12 mL·kg-1·d-1 (range,2.0-37.5 mL·kg-1·d-1). Thirty-seven (38.9%) patients had pleural drainage for more than 15 days,and the volume in 35 (36.8%) patients exceeded 25 mL·kg-1·d-1. Nineteen (20%) patients required placement of additional chest tubes for re-accumulation of pleural effusion after removal of previous chest tubes. Fifteen (17.8%) patients were hospitalized again due to pleural effusion after discharge. The median length of hospital stay after the operation was 14 days (range,4-78 days). Multivariate analysis results showed that non-fenestration,low preoperative oxygen saturation,and postoperative infections were independent risk factors for prolonged duration of pleural drainage (P<0.05). Long cardiopulmonary bypass time,non-fenestration,small conduit size,and low preoperative oxygen saturation were independent risk factors for excessive volume of pleural drainage (P<0.05).Conclusions For reduing postoperative duration and volume of pleural drainage following Fontan procedure,it seems to be important to improve the preoperative oxygen saturation,use large size of conduit,shorten cardiopulmonary bypass time,and make fenestration during the operation,as well as avoid postoperative infections.展开更多
The high sulfur coal from southwest of China was used to examine the influence of different factors such as irradiation time, particle size of coal, and leachant (Na2CO3, NaOH and CuCl22H2O)on the conversion rate of p...The high sulfur coal from southwest of China was used to examine the influence of different factors such as irradiation time, particle size of coal, and leachant (Na2CO3, NaOH and CuCl22H2O)on the conversion rate of pyrite to pyrrhotite by microwave irradiation. Single factor experiment was performed firstly, then orthogonal test method was used to explore these factors. The result shows that the optimal treating conditions for the conversion are a treatment time of 3 min, a particle size from 0.086 mm to 0.102 mm, and a favorable leachant of sodium hydroxide. Under these conditions the conversion rate of pyrite can reach 45.7 %.展开更多
This data article describes the dataset from a national cross-sectional questionnaire survey on Chinese internal migrants in 2017.The survey was part of the Chinese Migrants Dynamic Survey,which is an annually conduct...This data article describes the dataset from a national cross-sectional questionnaire survey on Chinese internal migrants in 2017.The survey was part of the Chinese Migrants Dynamic Survey,which is an annually conducted large-scale national questionnaire survey on internal migrants.The respondents in the described dataset were migrants and registered local residents aged over 15 years old.A multistage stratified probability-proportionalto-size(PPS) sampling method based on the 2016 annual report data of China Migrant Population was adopted.The questionnaire was designed to collect demographic information of respondents and their family members,intention of migration or settlement,health status,health services accessibility,social integration,and epidemic influencing factors of common diseases,including hypertension,type 2 diabetes,diarrhea,fever,rash,icterus,conjunctival redness,cold,and other illnesses or injuries.The sample population in this survey include 13,998 internal migrants and 14,000 registered local residents from eight domestic cities/prefecture/districts across China.It is the most widely covering and highly representative dataset on common diseases and influencing factors of internal migrants in China.The dataset can be used to study common diseases and influencing factors among floating Chinese population.It provides data support for government to improve healthcare accessibility and the equity of public health services for internal migrants in China.展开更多
CO_(2)huff and puff experiments of different injection parameters,production parameters and soaking time were carried out on large-scale cubic and long columnar outcrop samples to analyze dynamic characteristics and i...CO_(2)huff and puff experiments of different injection parameters,production parameters and soaking time were carried out on large-scale cubic and long columnar outcrop samples to analyze dynamic characteristics and influencing factors of CO_(2)huff and puff and the contribution of sweeping mode to recovery.The experimental results show that the development process of CO_(2)huff and puff can be divided into four stages,namely,CO_(2)backflow,production of gas with some oil,high-speed oil production,and oil production rate decline stages.The production of gas with some oil stage is dominated by free gas displacement,and the high-speed oil production stage is dominated by dissolved gas displacement.CO_(2)injection volume and development speed are the major factors affecting the oil recovery.The larger the injected CO_(2)volume and the lower the development speed,the higher the oil recovery will be.The reasonable CO_(2)injection volume and development speed should be worked out according to oilfield demand and economic evaluation.There is a reasonable soaking time in CO_(2)huff and puff.Longer soaking time than the optimum time makes little contribution to oil recovery.In field applications,the stability of bottom hole pressure is important to judge whether the soaking time is sufficient during the huff period.The oil recovery of CO_(2)huff and puff mainly comes from the contribution of flow sweep and diffusion sweep,and diffusion sweep contributes more to the oil recovery when the soaking time is sufficient.展开更多
Objective To analyze the influencing factors of the functional significance determined by fractional flow reserve （FFR） in interme- diate coronary artery stenosis. Methods The study enrolled 143 patients with 203 in...Objective To analyze the influencing factors of the functional significance determined by fractional flow reserve （FFR） in interme- diate coronary artery stenosis. Methods The study enrolled 143 patients with 203 intermediate coronary lesions. Pressure-derived FFR of these lesions was gained at maximal hyperemia induced by intravenous adenosine infusion. An FFR 〈 0.80 was considered as abnormal functional significance. Anatomic parameters at the lesion sites were obtained by off-line quantitative coronary angiography analysis （QCA）. The predictive value of the demographic characteristics and anatomic parameters for FFR in these intermediate lesions was assessed using multiple linear and binary logistic regression analysis. Results Overall, FFR 〈 0.8 was found in 70 （34%） of the total 203 intermediate coronary lesions. FFR values were positively correlated with QCA-measured minimum lumen diameters （MLD, r = 0.372, P = 0.000） and the reference vessel diameters （RVD, r = 0.217, P〈 0.002） were negatively correlated with percent area stenosis （AS, r = -0.251, P = 0.000） and percent diameter stenosis （DS, r = -0.210, P = 0.000）. Age, MLD and the lesion location in different coronary arteries were the inde- pendent determinants of FFR 〈 0.8. Conclusions MLD can predict the functional significance of intermediate coronary stenosis, while age and the lesion location in different coronary arteries should be taken into account as important influencing factors of FFR values.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.52222904 and 52309117)China Postdoctoral Science Foundation(Nos.2022TQ0168 and 2023M731895).
文摘Ocean energy has progressively gained considerable interest due to its sufficient potential to meet the world’s energy demand,and the blade is the core component in electricity generation from the ocean current.However,the widened hydraulic excitation frequency may satisfy the blade resonance due to the time variation in the velocity and angle of attack of the ocean current,even resulting in blade fatigue and destructively interfering with grid stability.A key parameter that determines the resonance amplitude of the blade is the hydrodynamic damping ratio(HDR).However,HDR is difficult to obtain due to the complex fluid-structure interaction(FSI).Therefore,a literature review was conducted on the hydrodynamic damping characteristics of blade-like structures.The experimental and simulation methods used to identify and obtain the HDR quantitatively were described,placing emphasis on the experimental processes and simulation setups.Moreover,the accuracy and efficiency of different simulation methods were compared,and the modal work approach was recommended.The effects of key typical parameters,including flow velocity,angle of attack,gap,rotational speed,and cavitation,on the HDR were then summarized,and the suggestions on operating conditions were presented from the perspective of increasing the HDR.Subsequently,considering multiple flow parameters,several theoretical derivations and semi-empirical prediction formulas for HDR were introduced,and the accuracy and application were discussed.Based on the shortcomings of the existing research,the direction of future research was finally determined.The current work offers a clear understanding of the HDR of blade-like structures,which could improve the evaluation accuracy of flow-induced vibration in the design stage.
文摘Foreign language teaching has shifted from teacher-centered teaching method to student-centered in recent years.Affective factors should be paid enough attention in teacher-learner interaction in.This paper aims to make an exploration into the effects of affective factors in college learners'classroom.
文摘Analyses the learners'linguistic environment,language,and the age which have made specific influence on the second language acquisition.These factors play a crucial influence on the second language acquisition,though some researchers hold different opinions about influence of categories and degree.
基金funded by the'Three-Year Action Plan for Strengthening the Public Health System in Shanghai(2015-2017)–Management of High-risk infants with Multidisciplinary Cooperation',project number:GWIV-19
文摘Background High-risk infants refer to newborns exposed to high-risk factors in the prenatal, natal or postnatal period. High-risk infants are at high risk of developmental retardation, and early identification of developmental abnormalities plays a vital role in improving high-risk infants' quality of life.Aims To describe the neurodevelopment of high-risk infants aged less than 1 year old, and to analyse the incidences and influencing factors of neurodevelopmental abnormalities in order to provide a basis for neurodevelopment monitoring and management of highrisk infants.Methods High-risk infants born between January 2016 and December 2016 in the maternity and infant health hospitals of three districts in Shanghai were followed up.The Gesell Developmental Scale was used to assess the neurodevelopmental level at the time of recruitment(0-2 months) and at 9 months. Univariate and multivariate analyses of the influencing factors were conducted.Results 484 high-risk infants(male 51 %, female 49%)with an average gestation age of 36.5±2.2 weeks were recruited. At the time of recruitment, the average age was2.1(0.8) months, and the developmental quotient(DQ)scores of full-term high-risk infants in motor(t=3.542,p=0.001), cognitive(t=3.125, p=0.002), language(t=3.189, p=0.002) and social(t=3.316, p=0.001) areas were higher than those of preterm infants. The incidences of developmental abnormalities of full-term high-risk infants in motor(χ~2 =9.452, p=0.002), cognitive(χ~2=6.258, p=0.012), language(χ~2 =12.319, p =0.001) and social(χ~2 =6.811, p=0.009) areas were lower than the preterm infants. At 9 months, there was no difference in the DQ scores and incidences of developmental abnormalities in four areas between full-term and preterm high-risk infants, and the incidence of developmental abnormalities was around 10%.Conclusion The incidence of neurodevelopmental abnormalities in high-risk infants aged less than 1 year old is high. Preterm birth and parental bad habits are significant factors affecting the neurodevelopment.Monitoring and early interventions help to improve highrisk infants' neurodevelopment.
基金supported by Study on Spatial Environmental Effect Model and Forestation Decision Support System for Forest Vegetation in Beijing(6161001)
文摘By analyzing the importance of influencing factors and conducting a comparative study of the effects of different sorting algorithms, a new method is proposed that is suitable for classifying the growth state of a natural Metasequoia glyptostroboides Hu and W.C. Cheng population. We studied 2817 M. glyptostroboides trees over 100 years old and analyzed their growth state by measuring 15 factors from stumpage, site condition, and environmental data. The dimensionality of all factors were reduced using the random forest algorithm, and we classified the remaining factors using the following algorithms: random forest, back-propagation(BP) neural networks, and support vector machine(SVM). The applicability of each sorting algorithm was analyzed. When all the d factors are used for classification and modeling, the model's overall accuracy,kappa coefficient and test accuracy were 85.5%, 0.739 and 85.8%, respectively. By reducing the dimensionality of the factors using the random forest algorithm, 11 factors most strongly influenced the classifications of the growth state of the Metasequoia population: diameter at breast height,height, crown width, age from stumpage data; longitude,latitude, elevation, slope aspect, gradient and slope position from the site condition data; and the edge of the field from the environmental data. For classifying the Metasequoia population, the random forest algorithm has the highest overall accuracy at 87.2%, which is 3.4 and 2.3% higher than the BP neural networks and SVM algorithms,respectively. The SVM algorithm is superior to the random forest algorithm with respect to classifying the state of mortality. The combination of the random forest and SVM algorithms and their combined information can be used to classify and predict the growth state of this natural M.glyptostroboides population to provide a scientific basis for its effective protection.
文摘Objective To investigate the influencing factors for prehospital delay in patients with acute myocardial infarction (AMI). Methods A total of 807 consecutive patients with AMI who presented to the emergency department of Beijing Anzhen Hospital were analyzed. The influence of several potential risk factors on the prehospital delay time (PDT) was evaluated by comparing patients admitted more than 2 hours after onset of chese pain with those admitted within 2 hours after onset. Results Among 807 patients, 402 came to the hospital within 2 hours while the others arrived at the hospital after 2 hours. The median PDT was 130 min. Among the potential variables, advanced age, history of diabetes mellitus, occurrence of symptom at night and use of emergency medical service significantly affected PDT by multivariate analysis. Conclusion Interventions aimed at reducing the prehospital delay in AMI should primarily focus on the awareness of the risk and help-seeking behavior of patients.
基金support of Nagoya Expressway Public Corporation for the data provision
文摘This study aims at identifying crash-influencing factors by facility type of Nagoya Urban Expressway, considering the interaction of geometry, traffic flow, and ambient conditions. Crash rate （CR） model is firstly developed separately at four facility types： basic, merge, and diverge segments and sharp curve. Traffic flows are thereby categorized, and based on the traffic categories, the significances of factors affecting crashes are analyzed by principal component analysis. The results reveal that, the CR at merge segment is significantly higher than those at basic and diverge segments in uncongested flow, while the value is not significantly different at the three facility types in congested flow. In both un- and congested flows, sharp curve has the worst safety performance in view of its highest CR. Regarding influencing factors, geometric design and traffic flow are most significant in un- and congested flows, respectively. As mainline flow increases, the effect of merging ratio affecting crash is on the rise at basic and merge segments as opposed to the decreasing significance of diverging ratio at diverge segment. Mean- while, longer acceleration and deceleration lanes are adverse to safety in uncongested flow, while shorter acceleration and deceleration lanes are adverse in congested flow. Due to its special geometric design, crashes at sharp curve are highly associated with the large centrifugal force and heavy restricted visibility.
基金Supported by the China National Science and Technology Major Project(2017ZX05013-001)
文摘To exert the imbibition between cracks and matrix effectively and enhance the development effect of tight oil reservoirs, a physical simulation method for imbibition in different scales of cores is developed by combining a high-pressure large-model physical simulation system and nuclear magnetic resonance technology(NMR) to investigate the influencing factors of imbibition process in tight reservoirs, and construct a quantitative evaluation method for the imbibition in water flooding. The results show that in the process of counter-current imbibition, the lower the permeability, the later the oil droplet precipitation, the longer the imbibition equilibrium time, and the lower the recovery degree. Fractures can effectively expand the area of imbibition and the front edge of imbibition in the contact between the dense matrix and water, reduce the resistance of oil discharge, and improve the imbibition speed and the degree of recovery. The more hydrophilic the rock, the higher the imbibition rate and imbibition recovery of tight rocks. In the process of co-current imbibition, the lower the permeability, the more obvious the imbibition, and the displacement recovery is positively correlated with permeability, while the imbibition recovery is negatively correlated with the permeability. It also shows that the imbibition distance of the cyclic water injection is greater than that of the counter-current imbibition, and the higher the permeability and the injection multiple, the longer the imbibition distance. The combination of large-scale volume fracturing with changing reservoir wettability and cyclic water injection is conducive to improving the imbibition ability of tight reservoirs.
基金supported by the National Social Science Foundation of China,2015(Grant No.ZDA059)the National Science Foundation of China,2013(Grant Nos.71373014 and 71303045)+3 种基金the Energy Foundation(USA)Projects,2012(Grant No.12YJAZH056)the special fund of the Research on the Generalized Virtual Economy,2011(Grant No.G-1111-15134)the Philosophy Social Planning project of the Ministry of Education of the People’s Republic of China,2011(Grant No.GX2011-1017Y)‘‘the Fundamental Research Funds for the Central Universities’’in UIBE(No.15YQ09)
文摘Henry Hub as an important transaction hub for natural gas sets the gas price standard in the USA. In this paper, the factors influencing Henry Hub natural gas prices are analyzed, and the major factors determining the price levels in the period between January 1997 and December 2016 are studied. It is found that economic conditions, total energy demand, US dollar exchange rate and gas consumption are the major factors. The mechanism of each factor influencing the Henry Hub natural gas price is also explored in the paper.
文摘The main mechanical properties of scrimber and Parallel Strand Lumber (PSL) were researched through techno-logical test. Experimental materials of scrimber are small log of Aspen, Dahurian larch and Birch. Experimental materials of PSL come from fishtail veneer strips at plywood plant of Aspen and Birch. In the laboratory conditions low quality small log and wood residues can yield scrimber and PSL with high strength. After the technological conditions of scrimber were compared with that of PSL, the main factors of influencing their properties were separately pointed out and the reasons influencing proper-ties have been analyzed in this paper. The results showed that the hot-pressing pressure is an important technological factor for scrimber. The ratio of veneer-strand length to thickness is a key technological factor for PSL.
基金National Natural Science Foundation of China (Grant No. 39600119)
文摘Fluorescent in situ hybridization (FISH) was applied to investigate the phylogenetic relationship among Dendranthema spp. Genomic DNA of wild species which was used as probe did not give specific signals, while 18S-26S rDNA from Arabidopsis, which was used as control probe, showed the loci on the target chromosomes clearly. Satisfied results of FISH were gotten when denaturing digoxingenen-labeled probe and chromosome together in oven at 80℃ for 1015min. There is little influence on the result by the stringency of washing when rDNA was used as probe. The result also indicates the limitation of genomic in situ hybridization (GISH) when used as an approach to analyze the phylogenetic relationship among Dendranthema spp. and the origin of cultivated chrysanthemum.
基金supported by the Daqing Oilfield Limited Company
文摘ASP-foam （ASPF） is a system prepared by injecting natural gas into the conventional alkali- surfactant-polymer （ASP） system. Foam can be formed in the porous media by the interaction of gas and surfactant in the ASP system. With the ASPF system, oil recovery is improved as the interfacial tension （IFT） is reduced to a relatively low level, and the swept volume is enlarged. In this paper, four surfactants were evaluated and characterized by IFT between ASP system and oil and the foaming performance. AI- kyl benzene sulfonate （ORS-41） was chosen as the surfactant to best reduce IFT between displacement fluids and oil and improve the foaming performance. The mechanisms of ASPF flooding were studied in this paper, the results show that the ASPF flooding not only enlarges the swept volume but also enhances the displacement efficiency. The effects of reservoir heterogeneity, the gas-liquid ratio of ASPF system, and the concentrations of polymer and surfactant on the displacement efficiency were studied. A field trial of ASPF flooding has also been conducted. Both the laboratory results and the field trial results show that the ASPF flooding can significantly increase the oil recovery, with a 30% increase in the proportion of the original oil in place recovered compared with water flooding.
基金the financial support from the SINOPEC (ST 13028)
文摘In this study, the main factors influencing the measurements by means of the off-line low-field 1H NMR in the lab were discussed base on a robust calibration model established by the PLS algorithm using 255 crude oil samples. The preheating temperature had a great influence on the viscosity of oil samples and the resolution of spectral analysis. The repeatability of spectral measurements was impacted by the metal and wax content of the oil samples. For the case of high wax content oils, the wax species began to crystallize in the course of determination that could affect the repeatability of spectral measurements. These factors have evidenced why the preheating devices and filter unit are necessary when low field NMR system is used in the online analysis process. The investigation is very important for the on-line application of the low field NMR.
文摘To analyze the positive influencing factors of Chinese telecom operators' EVA(Economic Value Added),this paper selects fifteen indicators based on the enterprise features of telecom operators and telecommunications industry characteristics,and then classifies these indicators into the following factors:operation scale,profitability,solvency and asset management ability by factor analysis.This paper also gives the priorities of these four factors by regression analysis,of which the operation scale is the most important factor.The research results point out a clear method for the telecom operatorsto increase their EVA in order to meet the performance appraisal from State-owned Assets Supervision and Administration Commission of the State Council.
基金supported by National Natural Science Foundation of China(No.50707012)Opening Project of State Key Laboratory of Electrical Insulation and Power Equipment in Xi'an Jiaotong University of China(No.EIPE11205)"Qing Lan Project" of Jiangsu Province,China
文摘The homogeneous dielectric barrier discharge （DBD） in atmospheric air between two symmetric-columnar copper electrodes with epoxy plates as the dielectric barriers is generated using a us pulse high voltage power supply. The discharge characteristics are studied by measurement of its electrical discharge parameters and observation of its light emission phenom- ena, and the main discharge parameters of the homogenous DBD, such as discharge current and average discharge power, are calculated. Results show that the discharge generated is a homogeneous one with one larger single current pulse of about 2 #s duration appearing in each voltage pulse, and its light emission is radially homogeneous and covers the entire surface of the two elec- trodes. The influences of applied voltage amplitude, air gap distance and barrier thickness on the transition of discharge modes are studied. With the increase of air gap distance, the discharge will transit from homogeneous mode to filamentary mode. The higher the thickness of dielectric barriers, the larger the air gap distance for generating the homogeneous discharge mode. The average discharge power increases non-linearly with increasing applied voltage amplitude, and decreases non-linearly with the increase of air gap distance and barrier thickness. In order to generate stable and homogeneous DBD with high discharge power, thin barriers distance should be used, and higher applied voltage amplitude should be applied to small air gap.
文摘Objective To investigate the association between preoperative,operative,and postoperative factors and persistent pleural effusion after the extracardiac Fontan procedure. Methods Ninety-five consecutive patients diagnosed with univentricular heart underwent extracardiac connection using Gore-Tax conduits at the Department of Children’s Heart Centre,Justus-Liebig-University Giessen in Germany from June 1996 to July 2007. The outcome measures were duration and volume of chest tube drainage after surgical intervention. The investigated factors included age and weight at the time of operation,anatomical diagnosis,preoperative oxygen saturation,mean pulmonary artery pressure,ventricular end-diastolic pressure,fenestration,cardiopulmonary bypass time,conduit size,postoperative pulmonary artery pressure,administration of angiotensin-converting enzyme inhibitors,and postoperative infection. Associations between these factors and persistent pleural effusion after the extracardiac Fontan procedure were analyzed. Results Every patient suffered postoperative effusion. The median duration of postoperative chest tube drainage was 9 days (range,3-69 days),and the median volume was 12 mL·kg-1·d-1 (range,2.0-37.5 mL·kg-1·d-1). Thirty-seven (38.9%) patients had pleural drainage for more than 15 days,and the volume in 35 (36.8%) patients exceeded 25 mL·kg-1·d-1. Nineteen (20%) patients required placement of additional chest tubes for re-accumulation of pleural effusion after removal of previous chest tubes. Fifteen (17.8%) patients were hospitalized again due to pleural effusion after discharge. The median length of hospital stay after the operation was 14 days (range,4-78 days). Multivariate analysis results showed that non-fenestration,low preoperative oxygen saturation,and postoperative infections were independent risk factors for prolonged duration of pleural drainage (P<0.05). Long cardiopulmonary bypass time,non-fenestration,small conduit size,and low preoperative oxygen saturation were independent risk factors for excessive volume of pleural drainage (P<0.05).Conclusions For reduing postoperative duration and volume of pleural drainage following Fontan procedure,it seems to be important to improve the preoperative oxygen saturation,use large size of conduit,shorten cardiopulmonary bypass time,and make fenestration during the operation,as well as avoid postoperative infections.
基金Project 2002CB211602 spported by the National Key Besearch and Development
文摘The high sulfur coal from southwest of China was used to examine the influence of different factors such as irradiation time, particle size of coal, and leachant (Na2CO3, NaOH and CuCl22H2O)on the conversion rate of pyrite to pyrrhotite by microwave irradiation. Single factor experiment was performed firstly, then orthogonal test method was used to explore these factors. The result shows that the optimal treating conditions for the conversion are a treatment time of 3 min, a particle size from 0.086 mm to 0.102 mm, and a favorable leachant of sodium hydroxide. Under these conditions the conversion rate of pyrite can reach 45.7 %.
文摘This data article describes the dataset from a national cross-sectional questionnaire survey on Chinese internal migrants in 2017.The survey was part of the Chinese Migrants Dynamic Survey,which is an annually conducted large-scale national questionnaire survey on internal migrants.The respondents in the described dataset were migrants and registered local residents aged over 15 years old.A multistage stratified probability-proportionalto-size(PPS) sampling method based on the 2016 annual report data of China Migrant Population was adopted.The questionnaire was designed to collect demographic information of respondents and their family members,intention of migration or settlement,health status,health services accessibility,social integration,and epidemic influencing factors of common diseases,including hypertension,type 2 diabetes,diarrhea,fever,rash,icterus,conjunctival redness,cold,and other illnesses or injuries.The sample population in this survey include 13,998 internal migrants and 14,000 registered local residents from eight domestic cities/prefecture/districts across China.It is the most widely covering and highly representative dataset on common diseases and influencing factors of internal migrants in China.The dataset can be used to study common diseases and influencing factors among floating Chinese population.It provides data support for government to improve healthcare accessibility and the equity of public health services for internal migrants in China.
文摘CO_(2)huff and puff experiments of different injection parameters,production parameters and soaking time were carried out on large-scale cubic and long columnar outcrop samples to analyze dynamic characteristics and influencing factors of CO_(2)huff and puff and the contribution of sweeping mode to recovery.The experimental results show that the development process of CO_(2)huff and puff can be divided into four stages,namely,CO_(2)backflow,production of gas with some oil,high-speed oil production,and oil production rate decline stages.The production of gas with some oil stage is dominated by free gas displacement,and the high-speed oil production stage is dominated by dissolved gas displacement.CO_(2)injection volume and development speed are the major factors affecting the oil recovery.The larger the injected CO_(2)volume and the lower the development speed,the higher the oil recovery will be.The reasonable CO_(2)injection volume and development speed should be worked out according to oilfield demand and economic evaluation.There is a reasonable soaking time in CO_(2)huff and puff.Longer soaking time than the optimum time makes little contribution to oil recovery.In field applications,the stability of bottom hole pressure is important to judge whether the soaking time is sufficient during the huff period.The oil recovery of CO_(2)huff and puff mainly comes from the contribution of flow sweep and diffusion sweep,and diffusion sweep contributes more to the oil recovery when the soaking time is sufficient.
文摘Objective To analyze the influencing factors of the functional significance determined by fractional flow reserve （FFR） in interme- diate coronary artery stenosis. Methods The study enrolled 143 patients with 203 intermediate coronary lesions. Pressure-derived FFR of these lesions was gained at maximal hyperemia induced by intravenous adenosine infusion. An FFR 〈 0.80 was considered as abnormal functional significance. Anatomic parameters at the lesion sites were obtained by off-line quantitative coronary angiography analysis （QCA）. The predictive value of the demographic characteristics and anatomic parameters for FFR in these intermediate lesions was assessed using multiple linear and binary logistic regression analysis. Results Overall, FFR 〈 0.8 was found in 70 （34%） of the total 203 intermediate coronary lesions. FFR values were positively correlated with QCA-measured minimum lumen diameters （MLD, r = 0.372, P = 0.000） and the reference vessel diameters （RVD, r = 0.217, P〈 0.002） were negatively correlated with percent area stenosis （AS, r = -0.251, P = 0.000） and percent diameter stenosis （DS, r = -0.210, P = 0.000）. Age, MLD and the lesion location in different coronary arteries were the inde- pendent determinants of FFR 〈 0.8. Conclusions MLD can predict the functional significance of intermediate coronary stenosis, while age and the lesion location in different coronary arteries should be taken into account as important influencing factors of FFR values.
