A fast and high precision spatial domain algorithm is presented for forward modeling of two-dimensional(2D)body gravity anomalies of arbitrary shape and density distribution.The new algorithm takes advantage of the co...A fast and high precision spatial domain algorithm is presented for forward modeling of two-dimensional(2D)body gravity anomalies of arbitrary shape and density distribution.The new algorithm takes advantage of the convolution properties of the expression for 2D gravity anomalies,uses a rectangular cell as a grid subdivision unit,and then 2D bodies with irregular cross-sections are approximated by a combination of 2D bodies with a rectangular cross section.The closed-form expression is used to calculate the gravitational anomalies of the combination of 2D bodies with a rectangular cross section.To improve computing effi ciency,the new algorithm uses a fast algorithm for the implementation of the Toeplitz matrix and vector multiplication.The synthetic 2D models with rectangular and circular cross-sections and constant and variable densities are designed to evaluate the computational accuracy and speed of the new algorithm.The experiment results show that the computation costs less than 6 s for a grid subdivision with 10000×10000 elements.Compared to the traditional forward modeling methods,the proposed method significantly improved computational effi ciency while guaranteeing computational accuracy.展开更多
The regions with shear stress and mean velocity gradient of opposite sign often exist in complex turbulent shear flows.In these cases,the eddy viscosity hypothesis breaks down.Hinze regards the,departure from eddy vis...The regions with shear stress and mean velocity gradient of opposite sign often exist in complex turbulent shear flows.In these cases,the eddy viscosity hypothesis breaks down.Hinze regards the,departure from eddy viscosity hypothesis as a result from transportation of mean momentum over distance by the large structures and arrives at a shear stress expression including the second order derivatives of the mean velocity.However,his expression greatly overestimates the shear stress.This implies that the flow particles are unlikely to have enough memory of the mean momentum over distance.By assuming the departure from eddy viscosity hypothesis as a result from transportation of the shear stress contained in smaller eddies over distance by the large structures,the present author has arrived at a new shear stress expression.The shear stress estimated so far is in good agreement with the experiments.展开更多
Longhole caving method was used to mine gently inclined thick orebody step by step in a test stope of tin mine under complex filling body. The problem that the complex filling body around the stope affects the stabili...Longhole caving method was used to mine gently inclined thick orebody step by step in a test stope of tin mine under complex filling body. The problem that the complex filling body around the stope affects the stability of roof thickness, chamber and spacer pillar in actual mining was investigated; meanwhile, the formed goaf during mining is so vulnerable that surrounding rock collapses early. Based on this point, elasticity mechanics and limit span theory were used to study separately the roof thickness and the span limit of goaf formed in mining, and then a reasonable roof thickness of 8 m and goaf span of 14 m are proposed. In addition, the stability of roof thickness, chamber and spacer pillar were investigated and analyzed by using numerical analysis method; meanwhile, the field monitoring on the displacement of caving chamber was conducted. The results show that the maximum compressive stress of surrounding rock is 20 MPa, and the maximum tensile stress is 1.2 MPa, which is less than the ultimate tensile strength of 2.4 MPa. Moreover, plastic zone has little influence on stope stability. In addition, the displacement of 11 mm is also smaller. The displacement monitoring results are consistent with the numerical results. Thus, the roof thickness and span of goaf proposed are safe.展开更多
In this study, two-dimensional correlation spectroscopy integrated with synchronous fluorescence and infrared absorption spectroscopy was employed to investigate the interaction between humic acids and aluminum coagul...In this study, two-dimensional correlation spectroscopy integrated with synchronous fluorescence and infrared absorption spectroscopy was employed to investigate the interaction between humic acids and aluminum coagulant at slightly acidic and neutral p H. Higher fluorescence quenching was produced for fulvic-like and humic-like fractions at p H 5. At p H 5, the humic-like fractions originating from the carboxylic acid, carboxyl and polysaccharide compounds were bound to aluminum first, followed by the fulvic-like fractions originating from the carboxyl and polysaccharide compounds. This finding also demonstrated that the activated functional groups of HA were involved in forming the Al-HA complex, which was accompanied by the removal of other groups by co-precipitation.Meanwhile, at p H 7, almost no fluorescence quenching occurred, and surface complexation was observed to occur, in which the activated functional groups were absorbed on the amorphous Al（OH）3. Two-dimensional FT-IR correlation spectroscopy indicated the sequence of HA structural change during coagulation with aluminum, with IR bands affected in the order of COOH〉 COO-〉NH deformation of amide Ⅱ〉 aliphatic hydroxyl C／OH at p H 5, and COO-〉aliphatic hydroxyl C／OH at p H 7. This study provides a promising pathway for analysis and insight into the priority of functional groups in the interaction between organic matters and metal coagulants.展开更多
Abardia and Bernig introduced the complex projection body and established the Brunn-Minkowski inequality for complex projection bodies.In this paper,we generalize their result and establish the Orlicz-Brunn-Minkowski ...Abardia and Bernig introduced the complex projection body and established the Brunn-Minkowski inequality for complex projection bodies.In this paper,we generalize their result and establish the Orlicz-Brunn-Minkowski inequality for complex projection bodies.And the Orlicz-Brunn-Minkowski inequality for polars of complex projection bodies is also obtained.展开更多
BACKGROUND Limb body wall complex(LBWC)is a fatal malformation characterized by major defects in the fetal abdominal or thoracic wall,visceral herniation,significant scoliosis or spina bifida,limb deformities,craniofa...BACKGROUND Limb body wall complex(LBWC)is a fatal malformation characterized by major defects in the fetal abdominal or thoracic wall,visceral herniation,significant scoliosis or spina bifida,limb deformities,craniofacial deformities,and umbilical cord abnormalities(short or absent umbilical cord).Early diagnosis of this condition is of great clinical significance for clinical intervention and pregnancy decision-making.With the rapid development of fetal ultrasound medicine,early pregnancy(11-13+6 wk)standardized prenatal ultrasound examinations have been widely promoted and applied.AIM To explore the value of prenatal ultrasound in the diagnosis of fetal LBWC syndrome during early pregnancy.METHODS The ultrasonographic data and follow-up results of 18 cases of fetal LBWC diagnosed by prenatal ultrasound during early pregnancy(11-13+6 wk)were retrospectively analyzed,and their ultrasonographic characteristics were analyzed.RESULTS Among the 18 fetuses with limb wall abnormalities,there were spinal dysplasia(18/18,100%),varying degrees of thoracoschisis and gastroschisis(18/18,100%),limb dysplasia in 6 cases(6/18,33%),craniocerebral malformations in 4 cases(4/18,22%),thickening of the transparent layer of the neck in 5 cases(5/18,28%),and umbilical cord abnormalities in 18 cases(18/18,100%),single umbilical artery in 5 cases.CONCLUSION Prenatal ultrasound in early pregnancy can detect LBWC as early as possible,and correct prenatal evaluation provides important guidance value for pregnancy decision-making and early intervention.展开更多
In this paper, based on the notion of mixed complex projection and generalized the recent works of other authors, we obtain some volume difference inequalities containing Brunn-Minkowski type inequality, Minkowski typ...In this paper, based on the notion of mixed complex projection and generalized the recent works of other authors, we obtain some volume difference inequalities containing Brunn-Minkowski type inequality, Minkowski type inequality and Aleksandrov-Fenchel inequality for the polars of mixed complex projection bodies.展开更多
In the paper a new two-dimensional 'man-WCV'(water cooling vest) mathematical model is developed. This model is of practical use: it can predict transient temperature responses and body temperature distributio...In the paper a new two-dimensional 'man-WCV'(water cooling vest) mathematical model is developed. This model is of practical use: it can predict transient temperature responses and body temperature distribution for a person in a nonuniform hot environment, doing various jobs and dressed in different clothes. In addition, the results calculated from the model can be used to optimize the distribution of the tube-net lined on the WCV and to evaluate an individual thermal conditioning system with cooling water. The results obtained from the model agree well with the author's experimental data.展开更多
Background Adjunct RCP to DHCA ensures some extent uninterrupted cerebral perfusion and that promotes one-stage repair of complex aortic arch anomaly.One-stage repair may induce longer myocardial ischemic time.So ther...Background Adjunct RCP to DHCA ensures some extent uninterrupted cerebral perfusion and that promotes one-stage repair of complex aortic arch anomaly.One-stage repair may induce longer myocardial ischemic time.So there evolved cerebral-myocardial perfusion to reduce myocardial ischemic time.Methods We reviewed 78 patients from January 2010 to July 2017 in our center.展开更多
Based on the notion of the complex L_(p)centroid body,we establish Brunn-Minkowski type inequalities and monotonicity inequalities for complex L_(p)centroid bodies in this article.Moreover,we obtain the affirmative fo...Based on the notion of the complex L_(p)centroid body,we establish Brunn-Minkowski type inequalities and monotonicity inequalities for complex L_(p)centroid bodies in this article.Moreover,we obtain the affirmative form of Shephard type problem for the complex L_(p)centroid bodies and its negative form.展开更多
In this paper, wave-body interactions under the effects of complex topography are investigated numerically by a two-phase incompressible Reynolds-Averaged Navier-Stokes(RANS) solver in OpenFOAM. A submerged bottom-sta...In this paper, wave-body interactions under the effects of complex topography are investigated numerically by a two-phase incompressible Reynolds-Averaged Navier-Stokes(RANS) solver in OpenFOAM. A submerged bottom-standing structure is distributed below the floating body, and the effects of the water depth and top width of the submerged structure on wave-body interactions are studied. The results show that the submerged structure can affect wave loads and roll motion. The vertical force can be amplified on the fixed body when the water depth of the submerged structure is smaller than half of the water depth of the body. The top width significantly affects the vertical force when the top width is smaller than the incident wave length and larger than the body width. For the free-rolling body, roll amplitude can be increased when the ratio of the incident wave length to the water depth of the submerged structure is large enough. On the resonance condition, roll amplitude is slightly reduced by the submerged structure. The effects of the top width on roll amplitude are remarkable when special conditions are fulfilled.展开更多
基金This work is jointly sponsored by the National Natural Science Foundation of China(No.41404106)the Scientific Research Startup Fund for Doctoral Program of Guilin University of Technology,Guangxi Natural Science Foundation Program(No.2018GXNSFBA138049)Guangxi Natural Science Foundation Program for Innovation Research Team(No.2016GXNSFGA380004).
文摘A fast and high precision spatial domain algorithm is presented for forward modeling of two-dimensional(2D)body gravity anomalies of arbitrary shape and density distribution.The new algorithm takes advantage of the convolution properties of the expression for 2D gravity anomalies,uses a rectangular cell as a grid subdivision unit,and then 2D bodies with irregular cross-sections are approximated by a combination of 2D bodies with a rectangular cross section.The closed-form expression is used to calculate the gravitational anomalies of the combination of 2D bodies with a rectangular cross section.To improve computing effi ciency,the new algorithm uses a fast algorithm for the implementation of the Toeplitz matrix and vector multiplication.The synthetic 2D models with rectangular and circular cross-sections and constant and variable densities are designed to evaluate the computational accuracy and speed of the new algorithm.The experiment results show that the computation costs less than 6 s for a grid subdivision with 10000×10000 elements.Compared to the traditional forward modeling methods,the proposed method significantly improved computational effi ciency while guaranteeing computational accuracy.
文摘The regions with shear stress and mean velocity gradient of opposite sign often exist in complex turbulent shear flows.In these cases,the eddy viscosity hypothesis breaks down.Hinze regards the,departure from eddy viscosity hypothesis as a result from transportation of mean momentum over distance by the large structures and arrives at a shear stress expression including the second order derivatives of the mean velocity.However,his expression greatly overestimates the shear stress.This implies that the flow particles are unlikely to have enough memory of the mean momentum over distance.By assuming the departure from eddy viscosity hypothesis as a result from transportation of the shear stress contained in smaller eddies over distance by the large structures,the present author has arrived at a new shear stress expression.The shear stress estimated so far is in good agreement with the experiments.
基金Project(2012BAK09B02-05)supported by the National Science and Technology Pillar Program during the 12th Five-Year Plan PeriodProject(11KF02)supported by the Research Fund of the State Key Laboratory of Coal Resources and Mine Safety
文摘Longhole caving method was used to mine gently inclined thick orebody step by step in a test stope of tin mine under complex filling body. The problem that the complex filling body around the stope affects the stability of roof thickness, chamber and spacer pillar in actual mining was investigated; meanwhile, the formed goaf during mining is so vulnerable that surrounding rock collapses early. Based on this point, elasticity mechanics and limit span theory were used to study separately the roof thickness and the span limit of goaf formed in mining, and then a reasonable roof thickness of 8 m and goaf span of 14 m are proposed. In addition, the stability of roof thickness, chamber and spacer pillar were investigated and analyzed by using numerical analysis method; meanwhile, the field monitoring on the displacement of caving chamber was conducted. The results show that the maximum compressive stress of surrounding rock is 20 MPa, and the maximum tensile stress is 1.2 MPa, which is less than the ultimate tensile strength of 2.4 MPa. Moreover, plastic zone has little influence on stope stability. In addition, the displacement of 11 mm is also smaller. The displacement monitoring results are consistent with the numerical results. Thus, the roof thickness and span of goaf proposed are safe.
基金supported by the National Key Technology Support Program(No.2014BAC13B06)the National Natural Science Foundation of China(Nos.51378414,51178376)+1 种基金the Program for Innovative Research Team in Shaanxi(No.2013KCT-13)the Program for New Century Excellent Talents in the University of Ministry of Education of China(No.NCET-12-1043)
文摘In this study, two-dimensional correlation spectroscopy integrated with synchronous fluorescence and infrared absorption spectroscopy was employed to investigate the interaction between humic acids and aluminum coagulant at slightly acidic and neutral p H. Higher fluorescence quenching was produced for fulvic-like and humic-like fractions at p H 5. At p H 5, the humic-like fractions originating from the carboxylic acid, carboxyl and polysaccharide compounds were bound to aluminum first, followed by the fulvic-like fractions originating from the carboxyl and polysaccharide compounds. This finding also demonstrated that the activated functional groups of HA were involved in forming the Al-HA complex, which was accompanied by the removal of other groups by co-precipitation.Meanwhile, at p H 7, almost no fluorescence quenching occurred, and surface complexation was observed to occur, in which the activated functional groups were absorbed on the amorphous Al（OH）3. Two-dimensional FT-IR correlation spectroscopy indicated the sequence of HA structural change during coagulation with aluminum, with IR bands affected in the order of COOH〉 COO-〉NH deformation of amide Ⅱ〉 aliphatic hydroxyl C／OH at p H 5, and COO-〉aliphatic hydroxyl C／OH at p H 7. This study provides a promising pathway for analysis and insight into the priority of functional groups in the interaction between organic matters and metal coagulants.
基金the Natural Science Foundation of Hunan Province(2019JJ50172)。
文摘Abardia and Bernig introduced the complex projection body and established the Brunn-Minkowski inequality for complex projection bodies.In this paper,we generalize their result and establish the Orlicz-Brunn-Minkowski inequality for complex projection bodies.And the Orlicz-Brunn-Minkowski inequality for polars of complex projection bodies is also obtained.
文摘BACKGROUND Limb body wall complex(LBWC)is a fatal malformation characterized by major defects in the fetal abdominal or thoracic wall,visceral herniation,significant scoliosis or spina bifida,limb deformities,craniofacial deformities,and umbilical cord abnormalities(short or absent umbilical cord).Early diagnosis of this condition is of great clinical significance for clinical intervention and pregnancy decision-making.With the rapid development of fetal ultrasound medicine,early pregnancy(11-13+6 wk)standardized prenatal ultrasound examinations have been widely promoted and applied.AIM To explore the value of prenatal ultrasound in the diagnosis of fetal LBWC syndrome during early pregnancy.METHODS The ultrasonographic data and follow-up results of 18 cases of fetal LBWC diagnosed by prenatal ultrasound during early pregnancy(11-13+6 wk)were retrospectively analyzed,and their ultrasonographic characteristics were analyzed.RESULTS Among the 18 fetuses with limb wall abnormalities,there were spinal dysplasia(18/18,100%),varying degrees of thoracoschisis and gastroschisis(18/18,100%),limb dysplasia in 6 cases(6/18,33%),craniocerebral malformations in 4 cases(4/18,22%),thickening of the transparent layer of the neck in 5 cases(5/18,28%),and umbilical cord abnormalities in 18 cases(18/18,100%),single umbilical artery in 5 cases.CONCLUSION Prenatal ultrasound in early pregnancy can detect LBWC as early as possible,and correct prenatal evaluation provides important guidance value for pregnancy decision-making and early intervention.
文摘In this paper, based on the notion of mixed complex projection and generalized the recent works of other authors, we obtain some volume difference inequalities containing Brunn-Minkowski type inequality, Minkowski type inequality and Aleksandrov-Fenchel inequality for the polars of mixed complex projection bodies.
文摘In the paper a new two-dimensional 'man-WCV'(water cooling vest) mathematical model is developed. This model is of practical use: it can predict transient temperature responses and body temperature distribution for a person in a nonuniform hot environment, doing various jobs and dressed in different clothes. In addition, the results calculated from the model can be used to optimize the distribution of the tube-net lined on the WCV and to evaluate an individual thermal conditioning system with cooling water. The results obtained from the model agree well with the author's experimental data.
文摘Background Adjunct RCP to DHCA ensures some extent uninterrupted cerebral perfusion and that promotes one-stage repair of complex aortic arch anomaly.One-stage repair may induce longer myocardial ischemic time.So there evolved cerebral-myocardial perfusion to reduce myocardial ischemic time.Methods We reviewed 78 patients from January 2010 to July 2017 in our center.
基金Supported by the National Natural Science Foundation of China(11901346)
文摘Based on the notion of the complex L_(p)centroid body,we establish Brunn-Minkowski type inequalities and monotonicity inequalities for complex L_(p)centroid bodies in this article.Moreover,we obtain the affirmative form of Shephard type problem for the complex L_(p)centroid bodies and its negative form.
基金supported by the National Key Research and Development Program of China under Grand No.2016YFB0200902supported by the Program for Guangdong Introducing Innovative and Entrepreneurial Teams under Grant No.2016ZT06D211
文摘In this paper, wave-body interactions under the effects of complex topography are investigated numerically by a two-phase incompressible Reynolds-Averaged Navier-Stokes(RANS) solver in OpenFOAM. A submerged bottom-standing structure is distributed below the floating body, and the effects of the water depth and top width of the submerged structure on wave-body interactions are studied. The results show that the submerged structure can affect wave loads and roll motion. The vertical force can be amplified on the fixed body when the water depth of the submerged structure is smaller than half of the water depth of the body. The top width significantly affects the vertical force when the top width is smaller than the incident wave length and larger than the body width. For the free-rolling body, roll amplitude can be increased when the ratio of the incident wave length to the water depth of the submerged structure is large enough. On the resonance condition, roll amplitude is slightly reduced by the submerged structure. The effects of the top width on roll amplitude are remarkable when special conditions are fulfilled.
