《宇航学报》英文版(Advances in Astronautics)由中国宇航学会与哈尔滨工业大学联合主办,与中国宇航学会主办的中文旗舰学术期刊《宇航学报》实施一体化建设,定位于覆盖宇航领域主要技术方向的综合性英文学术期刊。本刊为英文季刊,与...《宇航学报》英文版(Advances in Astronautics)由中国宇航学会与哈尔滨工业大学联合主办,与中国宇航学会主办的中文旗舰学术期刊《宇航学报》实施一体化建设,定位于覆盖宇航领域主要技术方向的综合性英文学术期刊。本刊为英文季刊,与施普林格·自然集团合作出版,并已被Ei Compendex、Scopus等权威数据库收录,为全球科研人员提供高质量的成果发表平台。展开更多
《宇航学报》英文版(Advances in Astronautics)由中国宇航学会与哈尔滨工业大学联合主办,与中国宇航学会主办的中文旗舰学术期刊《宇航学报》实施一体化建设,定位于覆盖宇航领域主要技术方向的综合性英文学术期刊。本刊为英文季刊,与...《宇航学报》英文版(Advances in Astronautics)由中国宇航学会与哈尔滨工业大学联合主办,与中国宇航学会主办的中文旗舰学术期刊《宇航学报》实施一体化建设,定位于覆盖宇航领域主要技术方向的综合性英文学术期刊。本刊为英文季刊,与施普林格·自然集团合作出版,并已被Ei Compendex、Scopus等权威数据库收录,为全球科研人员提供高质量的成果发表平台。展开更多
Objective:Albumin-globulin ratio(AGR),prognostic nutritional index(PNI),and platelet to-lymphocyte ratio(PLR)have been validated as prognostic factors for gastric cancer(GC).However,significant gender differences exis...Objective:Albumin-globulin ratio(AGR),prognostic nutritional index(PNI),and platelet to-lymphocyte ratio(PLR)have been validated as prognostic factors for gastric cancer(GC).However,significant gender differences exist in albumin levels and inflammatory cell counts,and further research is required to understand how these differences influence GC prognosis.This study aims to investigate the prognostic impact of nutritional and inflammatory indicators on GC patients undergoing radical surgery,as well as the influence of gender on these indicators’prognostic value.Methods:The study included 596 patients with advanced GC hospitalized in the Department of Gastrointestinal Surgery,General Surgery,Xiangya Hospital of Central South University from January 2012 to December 2016.Receiver operating characteristic(ROC)analysis was performed to determine cutoff values for nutritional and inflammatory factors.Univariate analysis was used to identify factors significantly affecting survival in GC patients,while multivariate and Kaplan-Meier analyses determined independent prognostic factors for GC.Results:Multivariate analysis revealed that postsurgical tumor node metastasis(pTNM)stage[stage II:hazard ratio(HR)=3.284,P=0.012;stage III:HR:8.062,P<0.001],low preoperative AGR(HR=1.499,P=0.012),and postoperative PNI(HR=1.503,P=0.008)were risk factors for overall survival in male patients after radical GC surgery.For female patients,pN2-3(HR=3.185,P<0.001),total gastrectomy(HR=2.286,P=0.004),low preoperative PLR(HR=1.702,P=0.027),and postoperative PNI(HR=1.943,P=0.011)were identified as risk factors for overall survival.Conclusion:Postoperative PNI is an independent risk factor for all advanced GC patients.Preoperative PLR is an independent prognostic factor only for female patients,while preoperative AGR is an independent prognostic factor only for male patients.Further research is warranted to investigate the gender-specific differences in GC prognosis.展开更多
Interest in the possibility of storing and transporting natural gas in the form of clathrate hydrates has been increasing in recent years, particularly in some gas-importing and exporting countries.The technologies ne...Interest in the possibility of storing and transporting natural gas in the form of clathrate hydrates has been increasing in recent years, particularly in some gas-importing and exporting countries.The technologies necessary for realizing this possibility may be classified into those relevant to the four serial processes (a) the formation of a hydrate, (b) the processing (dewatering, pelletizing, etc. ) of the formed hydrate, (c) the storage and transportation of the processed hydrate, and (d) the regasification (dissociation) of the hydrate. The technological development of any of these processes is still at an early stage. For hydrate formation, for example, various rival operations have been proposed. However,many of them have never been subjected to actual tests for practical use. More efforts are required for examining the different hydrate-formation technologies and for rating them by comparison. The general design of the processing of the formed hydrate inevitably depends on both the hydrate-formation process and the storage/transportation process, hence it has a wide variability. The major uncertainty in the storage-process design lies in the as-yet unclarified utility of the "self-preservation" effect of the naturalgas hydrates. The process design as well as the relevant cost evaluation should strongly depend on whether the hydrates are well preserved at atmospheric pressure in large-scale storage facilities. The regasification process has been studied less extensively than the former processes. The state of the art of the technological development in each of the serial processes is reviewed, placing emphasis on the hydrate formation process.展开更多
To keep the tunnel face stable is very important for tunnel construction.In this paper,the tunnel face stability under the advanced pipe was analyzed using the Winkler foundation model and rigid limit equilibrium.The ...To keep the tunnel face stable is very important for tunnel construction.In this paper,the tunnel face stability under the advanced pipe was analyzed using the Winkler foundation model and rigid limit equilibrium.The tunnel face deformation characteristics were also analyzed using the numerical simulation.The influence of parameters on the deflection of the pipe roof and the stability of the tunnel face were discussed.The results show that the tunnel face stability can be improved through increasing the pipe diameter,decreasing the initial displacement at the beginning of the pipe seat,and adopting the short round length and small excavation height.With the increase of tunnel burial depth,the safety factor of tunnel face stability first decreases,then increases,and then remains unchanged.The deformation at the center of the tunnel face is larger than the deformation at the surround sides and at the corner.The horizontal displacement varies little with the increasing of the pipe length.The horizontal displacement at the center of the tunnel face increases with the increase of the pipe ring spacing and the pipe longitudinal spacing.There is an optimum external angle.展开更多
Background and objective Lung cancer is the most common cause of death in men in the world and in Indonesia where nonsmall cell carcinoma lung cancer(NSCLC) constitutes 85% of all lung cancer cases. The high mortality...Background and objective Lung cancer is the most common cause of death in men in the world and in Indonesia where nonsmall cell carcinoma lung cancer(NSCLC) constitutes 85% of all lung cancer cases. The high mortality rate is due to a poor prognosis and is often diagnosed as having advanced stages. If it is known at the initial stage, the prognosis of lung cancer will be better. Prognosis can be predicted with a marker of prognostic biology, one of which is micro RNA(mi RNA). This study aims to prove that serum mi RNA can be predictive biological marker and prognosis in NSCLC patients in Indonesia.Methods This study was cohort retrospective among 52 subjects in "Dharmais" Hospital National Cancer Center. Sample was obtained from patients’ serum. Mi R-34, mi R-148, mi R-155 and mi R-222 serum are measured through Real-Time PCR(q PCR). Data were analyzed and interpreted with descriptive analysis, bivariate analysis(Mann Whitney-U for two type of variables or Kruskal-Wallis for more than two type of variables. Kaplan-Meier analysis was used to know association between characteristic which are sociodemographic, performance status, clinico-pathology, and survival rate in mi RNA expression. Results From this study, mi RNA expression: mi R-34(46.15%), mi R-148(23.08%), mi R-155(40.38%) and mi R-222(32.69%). Performance status score was statistically significant correlation with mi R-148(P=0.049) and mi R-222(P=0.018). High mi R-34 is associated with multiple M1 b metastatic type(P=0.020), cancer cell type(adenocarcinoma, P=0.009) and adenocarcinoma epidermal growth factor receptor(EGFR) mutation(negative, P=0.031). There was a significant correlation between the high mi R-222 as a poor prognosis in advanced stage NSCLC with M1 b metastasis(Median Survival/MS: 27 d, P=0.049) and positive EGFR mutations(MS: 74 d, P=0.049) and correlation of mi R-155 with adenocarcinoma(MS: 69 d, P=0.034) and positive EGFR gene mutations(MS: 58 d, P=0.023).Conclusion High mi R-34 expression in advanced stage NSCLC is the predictive factor for multiple metastatic, adenocarcinoma cell type and adenocarcinoma negative EGFR mutation. High expression of mi R-155 and mi R-222 are poor prognoses, especially high mi R-222 found in metastasis M1 b and positive EGFR mutation and mi R-155 found in adenocarcinoma and positive EGFR gene mutations. Further studies regarding correlation between mi RNA and survival rate are needed.展开更多
Experiments were conducted to investigate the behavior of the sequential system of intensified zero-valent iron process(IZVI) and anaerobic filter and biological aerated filter(AF/BAF) reactors for advanced treatment ...Experiments were conducted to investigate the behavior of the sequential system of intensified zero-valent iron process(IZVI) and anaerobic filter and biological aerated filter(AF/BAF) reactors for advanced treatment of biologically pretreated coking wastewater. Particular attention was paid to the performance of the integrated system for the removal of chemical oxygen demand(COD), ammonia nitrogen(NH3-N) and total nitrogen(TN). The average removal efficiencies of COD, NH3-N and TN were 76.28%, 96.76% and 59.97%, with the average effluent mass concentrations of 56, 0.53 and 18.83 mg/L, respectively, reaching the first grade of the national discharge standard. Moreover, the results of gas chromatography/mass spectrum(GC/MS) and gel permeation chromatography(GPC) analysis demonstrated that the refractory organic compounds with high relative molecular mass were partly removed in IZVI process by the function of oxidation-reduction, flocculation and adsorption which could also enhance the biodegradability of the system effluent. The removal efficiencies of NH3-N and TN were achieved mainly in the subsequent AF/BAF reactors by nitrification and denitrification. Overall, the results obtained show that the application of IZVI in combination with AF/BAF is a promising technology for advanced treatment of biologically pretreated coking wastewater.展开更多
Waxy crude oil exhibits complex shear-and-thermal-history-dependent non-Newtonian behaviors.In the past 10 years,driven by the petroleum industry,crude oil rheology has been an active field.Studies on crude oil rheolo...Waxy crude oil exhibits complex shear-and-thermal-history-dependent non-Newtonian behaviors.In the past 10 years,driven by the petroleum industry,crude oil rheology has been an active field.Studies on crude oil rheology have been passing a way from simply relying on rheological measurements,through quantitative experimental simulation of shear and thermal history effects in pipelining,to recent development of correlation between flow properties and shear and thermal history.Currently,the study is toward quantitative inquiry of relations between the rheological behaviors and micro-structures of wax crystals as well as oil compositions.Advances achieved by the author' team are summarized,including simulation of the thermal and shear history effects,correlations and computation of flow properties,fractal characterization of morphology and structure of wax crystals,relations of rheological behaviors to fractal dimension and oil compositions,and the most successful example of the application of rheology in crude oil pipelining.Future studies are prospected.展开更多
Advanced traveler information systems （ATIS） can not only improve drivers＇ accessibility to the more accurate route travel time information, but also can improve drivers＇ adaptability to the stochastic network cap...Advanced traveler information systems （ATIS） can not only improve drivers＇ accessibility to the more accurate route travel time information, but also can improve drivers＇ adaptability to the stochastic network capacity degradations. In this paper, a mixed stochastic user equilibrium model was proposed to describe the interactive route choice behaviors between ATIS equipped and unequipped drivers on a degradable transport network. In the proposed model the information accessibility of equipped drivers was reflected by lower degree of uncertainty in their stochastic equilibrium flow distributions, and their behavioral adaptability was captured by multiple equilibrium behaviors over the stochastic network state set. The mixed equilibrium model was formulated as a fixed point problem defined in the mixed route flows, and its solution was achieved by executing an iterative algorithm. Numerical experiments were provided to verify the properties of the mixed network equilibrium model and the efficiency of the iterative algorithm.展开更多
A compensation implementation scheme of the advanced targeting process based on the fine tracking system is proposed in this paper.Based on the working process of the quantum positioning system(QPS)and its acquisition...A compensation implementation scheme of the advanced targeting process based on the fine tracking system is proposed in this paper.Based on the working process of the quantum positioning system(QPS)and its acquisition,tracking and pointing(ATP)system,the advanced targeting subsystem of the ATP system is designed.Based on six orbital parameters of the quantum satellite Mozi,the advanced targeting azimuth angle and pitch angle are transformed into the dynamic tracking center of the fine tracking system in the ATP system.The deviation of the advanced targeting process is analyzed.In the Simulink,the simulation experiment of the ATP system considering the deviation compensation of the advanced targeting is carried out,and the results are analyzed.展开更多
Based on the specialty of major rock-forning minerals and elementary composition of metamorphite,the detailed and systematical review,analysis and summary are completed for a series of lithology and reservoir fracture...Based on the specialty of major rock-forning minerals and elementary composition of metamorphite,the detailed and systematical review,analysis and summary are completed for a series of lithology and reservoir fracture identification teehnologies with logging that are recent years.Research shows that nuclear logging series in conventional logging are more favorable to identify the metanorphie lithology.ECS(elemental capturespectrosoopy)and other new logging lechnologies can be applied to identify metamorphic lithology.Due to theolex and di-verse metamorphic lithologies,the correspending reservoir identification standard should be established for metamorphic reservoir identificat lithology identification,The applicable conventional logging methods for metamorphic reservoir fracture identification mainly incldle dual lat ging,scoustic logging,dual lateral logging-microspherical focus,borehole diameter logging,natural gamma ray spectrology baging,etc.In additie acoustic-resistivity imaging logging,multipolar array acoustic logging,cross dipole acoustic logging and other new logging tec nologies with unique ad-vantages are increasingly applied for metamorphic reservoir fractureidentification.Currently,there are no gener appli sandards for logging i-dentification of metamorphic lithology and reservoir fracture.The specific metamorphic reservoir development a field actual data in specific ar-eas should be considered to study the logging identification and evaluation.展开更多
To explore the influence of intelligent highways and advanced traveler information systems(ATIS)on path choice behavior,a day-to-day(DTD)traffic flow evolution model with information from intelligent highways and ATIS...To explore the influence of intelligent highways and advanced traveler information systems(ATIS)on path choice behavior,a day-to-day(DTD)traffic flow evolution model with information from intelligent highways and ATIS is proposed,whereby the network reliability and experiential learning theory are introduced into the decision process for the travelers’route choice.The intelligent highway serves all the travelers who drive on it,whereas ATIS serves vehicles equipped with information systems.Travelers who drive on intelligent highways or vehicles equipped with ATIS determine their trip routes based on real-time traffic information,whereas other travelers use both the road network conditions from the previous day and historical travel experience to choose a route.Both roadway capacity degradation and travel demand fluctuations are considered to demonstrate the uncertainties in the network.The theory of traffic network flow is developed to build a DTD model considering information from intelligent highway and ATIS.The fixed point theorem is adopted to investigate the equivalence,existence and stability of the proposed DTD model.Numerical examples illustrate that using a high confidence level and weight parameter for the traffic flow reduces the stability of the proposed model.The traffic flow reaches a steady state as travelers’routes shift with repetitive learning of road conditions.The proposed model can be used to formulate scientific traffic organization and diversion schemes during road expansion or reconstruction.展开更多
To improve the computational efficiency of the reliability-based design optimization(RBDO) of flexible mechanism, particle swarm optimization-advanced extremum response surface method(PSO-AERSM) was proposed by integr...To improve the computational efficiency of the reliability-based design optimization(RBDO) of flexible mechanism, particle swarm optimization-advanced extremum response surface method(PSO-AERSM) was proposed by integrating particle swarm optimization(PSO) algorithm and advanced extremum response surface method(AERSM). Firstly, the AERSM was developed and its mathematical model was established based on artificial neural network, and the PSO algorithm was investigated. And then the RBDO model of flexible mechanism was presented based on AERSM and PSO. Finally, regarding cross-sectional area as design variable, the reliability optimization of flexible mechanism was implemented subject to reliability degree and uncertainties based on the proposed approach. The optimization results show that the cross-section sizes obviously reduce by 22.96 mm^2 while keeping reliability degree. Through the comparison of methods, it is demonstrated that the AERSM holds high computational efficiency while keeping computational precision for the RBDO of flexible mechanism, and PSO algorithm minimizes the response of the objective function. The efforts of this work provide a useful sight for the reliability optimization of flexible mechanism, and enrich and develop the reliability theory as well.展开更多
文摘《宇航学报》英文版(Advances in Astronautics)由中国宇航学会与哈尔滨工业大学联合主办,与中国宇航学会主办的中文旗舰学术期刊《宇航学报》实施一体化建设,定位于覆盖宇航领域主要技术方向的综合性英文学术期刊。本刊为英文季刊,与施普林格·自然集团合作出版,并已被Ei Compendex、Scopus等权威数据库收录,为全球科研人员提供高质量的成果发表平台。
文摘《宇航学报》英文版(Advances in Astronautics)由中国宇航学会与哈尔滨工业大学联合主办,与中国宇航学会主办的中文旗舰学术期刊《宇航学报》实施一体化建设,定位于覆盖宇航领域主要技术方向的综合性英文学术期刊。本刊为英文季刊,与施普林格·自然集团合作出版,并已被Ei Compendex、Scopus等权威数据库收录,为全球科研人员提供高质量的成果发表平台。
基金supported by the National Natural Science Foundation of China(8197103463).
文摘Objective:Albumin-globulin ratio(AGR),prognostic nutritional index(PNI),and platelet to-lymphocyte ratio(PLR)have been validated as prognostic factors for gastric cancer(GC).However,significant gender differences exist in albumin levels and inflammatory cell counts,and further research is required to understand how these differences influence GC prognosis.This study aims to investigate the prognostic impact of nutritional and inflammatory indicators on GC patients undergoing radical surgery,as well as the influence of gender on these indicators’prognostic value.Methods:The study included 596 patients with advanced GC hospitalized in the Department of Gastrointestinal Surgery,General Surgery,Xiangya Hospital of Central South University from January 2012 to December 2016.Receiver operating characteristic(ROC)analysis was performed to determine cutoff values for nutritional and inflammatory factors.Univariate analysis was used to identify factors significantly affecting survival in GC patients,while multivariate and Kaplan-Meier analyses determined independent prognostic factors for GC.Results:Multivariate analysis revealed that postsurgical tumor node metastasis(pTNM)stage[stage II:hazard ratio(HR)=3.284,P=0.012;stage III:HR:8.062,P<0.001],low preoperative AGR(HR=1.499,P=0.012),and postoperative PNI(HR=1.503,P=0.008)were risk factors for overall survival in male patients after radical GC surgery.For female patients,pN2-3(HR=3.185,P<0.001),total gastrectomy(HR=2.286,P=0.004),low preoperative PLR(HR=1.702,P=0.027),and postoperative PNI(HR=1.943,P=0.011)were identified as risk factors for overall survival.Conclusion:Postoperative PNI is an independent risk factor for all advanced GC patients.Preoperative PLR is an independent prognostic factor only for female patients,while preoperative AGR is an independent prognostic factor only for male patients.Further research is warranted to investigate the gender-specific differences in GC prognosis.
文摘Interest in the possibility of storing and transporting natural gas in the form of clathrate hydrates has been increasing in recent years, particularly in some gas-importing and exporting countries.The technologies necessary for realizing this possibility may be classified into those relevant to the four serial processes (a) the formation of a hydrate, (b) the processing (dewatering, pelletizing, etc. ) of the formed hydrate, (c) the storage and transportation of the processed hydrate, and (d) the regasification (dissociation) of the hydrate. The technological development of any of these processes is still at an early stage. For hydrate formation, for example, various rival operations have been proposed. However,many of them have never been subjected to actual tests for practical use. More efforts are required for examining the different hydrate-formation technologies and for rating them by comparison. The general design of the processing of the formed hydrate inevitably depends on both the hydrate-formation process and the storage/transportation process, hence it has a wide variability. The major uncertainty in the storage-process design lies in the as-yet unclarified utility of the "self-preservation" effect of the naturalgas hydrates. The process design as well as the relevant cost evaluation should strongly depend on whether the hydrates are well preserved at atmospheric pressure in large-scale storage facilities. The regasification process has been studied less extensively than the former processes. The state of the art of the technological development in each of the serial processes is reviewed, placing emphasis on the hydrate formation process.
基金Project(20A187)supported by the Hunan Provincial Department of Education,ChinaProjects(51408216,51308209)supported by the National Natural Science Foundation of China。
文摘To keep the tunnel face stable is very important for tunnel construction.In this paper,the tunnel face stability under the advanced pipe was analyzed using the Winkler foundation model and rigid limit equilibrium.The tunnel face deformation characteristics were also analyzed using the numerical simulation.The influence of parameters on the deflection of the pipe roof and the stability of the tunnel face were discussed.The results show that the tunnel face stability can be improved through increasing the pipe diameter,decreasing the initial displacement at the beginning of the pipe seat,and adopting the short round length and small excavation height.With the increase of tunnel burial depth,the safety factor of tunnel face stability first decreases,then increases,and then remains unchanged.The deformation at the center of the tunnel face is larger than the deformation at the surround sides and at the corner.The horizontal displacement varies little with the increasing of the pipe length.The horizontal displacement at the center of the tunnel face increases with the increase of the pipe ring spacing and the pipe longitudinal spacing.There is an optimum external angle.
文摘Background and objective Lung cancer is the most common cause of death in men in the world and in Indonesia where nonsmall cell carcinoma lung cancer(NSCLC) constitutes 85% of all lung cancer cases. The high mortality rate is due to a poor prognosis and is often diagnosed as having advanced stages. If it is known at the initial stage, the prognosis of lung cancer will be better. Prognosis can be predicted with a marker of prognostic biology, one of which is micro RNA(mi RNA). This study aims to prove that serum mi RNA can be predictive biological marker and prognosis in NSCLC patients in Indonesia.Methods This study was cohort retrospective among 52 subjects in "Dharmais" Hospital National Cancer Center. Sample was obtained from patients’ serum. Mi R-34, mi R-148, mi R-155 and mi R-222 serum are measured through Real-Time PCR(q PCR). Data were analyzed and interpreted with descriptive analysis, bivariate analysis(Mann Whitney-U for two type of variables or Kruskal-Wallis for more than two type of variables. Kaplan-Meier analysis was used to know association between characteristic which are sociodemographic, performance status, clinico-pathology, and survival rate in mi RNA expression. Results From this study, mi RNA expression: mi R-34(46.15%), mi R-148(23.08%), mi R-155(40.38%) and mi R-222(32.69%). Performance status score was statistically significant correlation with mi R-148(P=0.049) and mi R-222(P=0.018). High mi R-34 is associated with multiple M1 b metastatic type(P=0.020), cancer cell type(adenocarcinoma, P=0.009) and adenocarcinoma epidermal growth factor receptor(EGFR) mutation(negative, P=0.031). There was a significant correlation between the high mi R-222 as a poor prognosis in advanced stage NSCLC with M1 b metastasis(Median Survival/MS: 27 d, P=0.049) and positive EGFR mutations(MS: 74 d, P=0.049) and correlation of mi R-155 with adenocarcinoma(MS: 69 d, P=0.034) and positive EGFR gene mutations(MS: 58 d, P=0.023).Conclusion High mi R-34 expression in advanced stage NSCLC is the predictive factor for multiple metastatic, adenocarcinoma cell type and adenocarcinoma negative EGFR mutation. High expression of mi R-155 and mi R-222 are poor prognoses, especially high mi R-222 found in metastasis M1 b and positive EGFR mutation and mi R-155 found in adenocarcinoma and positive EGFR gene mutations. Further studies regarding correlation between mi RNA and survival rate are needed.
基金Project(2006BAJ04A)suppprted by the National Sci-Tech Support Plan,China
文摘Experiments were conducted to investigate the behavior of the sequential system of intensified zero-valent iron process(IZVI) and anaerobic filter and biological aerated filter(AF/BAF) reactors for advanced treatment of biologically pretreated coking wastewater. Particular attention was paid to the performance of the integrated system for the removal of chemical oxygen demand(COD), ammonia nitrogen(NH3-N) and total nitrogen(TN). The average removal efficiencies of COD, NH3-N and TN were 76.28%, 96.76% and 59.97%, with the average effluent mass concentrations of 56, 0.53 and 18.83 mg/L, respectively, reaching the first grade of the national discharge standard. Moreover, the results of gas chromatography/mass spectrum(GC/MS) and gel permeation chromatography(GPC) analysis demonstrated that the refractory organic compounds with high relative molecular mass were partly removed in IZVI process by the function of oxidation-reduction, flocculation and adsorption which could also enhance the biodegradability of the system effluent. The removal efficiencies of NH3-N and TN were achieved mainly in the subsequent AF/BAF reactors by nitrification and denitrification. Overall, the results obtained show that the application of IZVI in combination with AF/BAF is a promising technology for advanced treatment of biologically pretreated coking wastewater.
文摘Waxy crude oil exhibits complex shear-and-thermal-history-dependent non-Newtonian behaviors.In the past 10 years,driven by the petroleum industry,crude oil rheology has been an active field.Studies on crude oil rheology have been passing a way from simply relying on rheological measurements,through quantitative experimental simulation of shear and thermal history effects in pipelining,to recent development of correlation between flow properties and shear and thermal history.Currently,the study is toward quantitative inquiry of relations between the rheological behaviors and micro-structures of wax crystals as well as oil compositions.Advances achieved by the author' team are summarized,including simulation of the thermal and shear history effects,correlations and computation of flow properties,fractal characterization of morphology and structure of wax crystals,relations of rheological behaviors to fractal dimension and oil compositions,and the most successful example of the application of rheology in crude oil pipelining.Future studies are prospected.
基金Projects(51378119,51578150)supported by the National Natural Science Foundation of China
文摘Advanced traveler information systems （ATIS） can not only improve drivers＇ accessibility to the more accurate route travel time information, but also can improve drivers＇ adaptability to the stochastic network capacity degradations. In this paper, a mixed stochastic user equilibrium model was proposed to describe the interactive route choice behaviors between ATIS equipped and unequipped drivers on a degradable transport network. In the proposed model the information accessibility of equipped drivers was reflected by lower degree of uncertainty in their stochastic equilibrium flow distributions, and their behavioral adaptability was captured by multiple equilibrium behaviors over the stochastic network state set. The mixed equilibrium model was formulated as a fixed point problem defined in the mixed route flows, and its solution was achieved by executing an iterative algorithm. Numerical experiments were provided to verify the properties of the mixed network equilibrium model and the efficiency of the iterative algorithm.
基金supported by the National Natural Science Foundation of China(61973290).
文摘A compensation implementation scheme of the advanced targeting process based on the fine tracking system is proposed in this paper.Based on the working process of the quantum positioning system(QPS)and its acquisition,tracking and pointing(ATP)system,the advanced targeting subsystem of the ATP system is designed.Based on six orbital parameters of the quantum satellite Mozi,the advanced targeting azimuth angle and pitch angle are transformed into the dynamic tracking center of the fine tracking system in the ATP system.The deviation of the advanced targeting process is analyzed.In the Simulink,the simulation experiment of the ATP system considering the deviation compensation of the advanced targeting is carried out,and the results are analyzed.
文摘Based on the specialty of major rock-forning minerals and elementary composition of metamorphite,the detailed and systematical review,analysis and summary are completed for a series of lithology and reservoir fracture identification teehnologies with logging that are recent years.Research shows that nuclear logging series in conventional logging are more favorable to identify the metanorphie lithology.ECS(elemental capturespectrosoopy)and other new logging lechnologies can be applied to identify metamorphic lithology.Due to theolex and di-verse metamorphic lithologies,the correspending reservoir identification standard should be established for metamorphic reservoir identificat lithology identification,The applicable conventional logging methods for metamorphic reservoir fracture identification mainly incldle dual lat ging,scoustic logging,dual lateral logging-microspherical focus,borehole diameter logging,natural gamma ray spectrology baging,etc.In additie acoustic-resistivity imaging logging,multipolar array acoustic logging,cross dipole acoustic logging and other new logging tec nologies with unique ad-vantages are increasingly applied for metamorphic reservoir fractureidentification.Currently,there are no gener appli sandards for logging i-dentification of metamorphic lithology and reservoir fracture.The specific metamorphic reservoir development a field actual data in specific ar-eas should be considered to study the logging identification and evaluation.
基金Project(71801115)supported by the National Natural Science Foundation of ChinaProject(2021M691311)supported by the Postdoctoral Science Foundation of ChinaProject(111041000000180001210102)supported by the Central Public Interest Scientific Institution Basal Research Fund,China。
文摘To explore the influence of intelligent highways and advanced traveler information systems(ATIS)on path choice behavior,a day-to-day(DTD)traffic flow evolution model with information from intelligent highways and ATIS is proposed,whereby the network reliability and experiential learning theory are introduced into the decision process for the travelers’route choice.The intelligent highway serves all the travelers who drive on it,whereas ATIS serves vehicles equipped with information systems.Travelers who drive on intelligent highways or vehicles equipped with ATIS determine their trip routes based on real-time traffic information,whereas other travelers use both the road network conditions from the previous day and historical travel experience to choose a route.Both roadway capacity degradation and travel demand fluctuations are considered to demonstrate the uncertainties in the network.The theory of traffic network flow is developed to build a DTD model considering information from intelligent highway and ATIS.The fixed point theorem is adopted to investigate the equivalence,existence and stability of the proposed DTD model.Numerical examples illustrate that using a high confidence level and weight parameter for the traffic flow reduces the stability of the proposed model.The traffic flow reaches a steady state as travelers’routes shift with repetitive learning of road conditions.The proposed model can be used to formulate scientific traffic organization and diversion schemes during road expansion or reconstruction.
基金Projects(51275138,51475025)supported by the National Natural Science Foundation of ChinaProject(12531109)supported by the Science Foundation of Heilongjiang Provincial Department of Education,China+1 种基金Projects(XJ2015002,G-YZ90)supported by Hong Kong Scholars Program,ChinaProject(2015M580037)supported by Postdoctoral Science Foundation of China
文摘To improve the computational efficiency of the reliability-based design optimization(RBDO) of flexible mechanism, particle swarm optimization-advanced extremum response surface method(PSO-AERSM) was proposed by integrating particle swarm optimization(PSO) algorithm and advanced extremum response surface method(AERSM). Firstly, the AERSM was developed and its mathematical model was established based on artificial neural network, and the PSO algorithm was investigated. And then the RBDO model of flexible mechanism was presented based on AERSM and PSO. Finally, regarding cross-sectional area as design variable, the reliability optimization of flexible mechanism was implemented subject to reliability degree and uncertainties based on the proposed approach. The optimization results show that the cross-section sizes obviously reduce by 22.96 mm^2 while keeping reliability degree. Through the comparison of methods, it is demonstrated that the AERSM holds high computational efficiency while keeping computational precision for the RBDO of flexible mechanism, and PSO algorithm minimizes the response of the objective function. The efforts of this work provide a useful sight for the reliability optimization of flexible mechanism, and enrich and develop the reliability theory as well.
