Vacuum vessel of the HT-7U is a fully welded toroidal structure with a noncircular cross-section nested in the bore of the TF coils. According to the requirement of the physics design, sixteen horizontal ports on outb...Vacuum vessel of the HT-7U is a fully welded toroidal structure with a noncircular cross-section nested in the bore of the TF coils. According to the requirement of the physics design, sixteen horizontal ports on outboard mid-plane and thirty-two vertical ports on the top and bottom are designed for diagnostics, plasma heating, current driving, vacuum pumping and gas puffing. Bellows on these port necks are used for flexible components to absorb the relative displacement in radial and vertical directions due to external load, thermal expansion or contrac-tion and assembly tolerance, and also used for isolation of mechanical vibration. For the support system of vacuum vessel it should be not only strong enough to withstand forces acting on the vessel interior components and the vessel itself due to the dead weight and electromagnetic inter-actions during plasma disruption, but also sufficiently flexible to be suited to thermal expansion during baking. In order to solve this contradiction a new kind of low rigid support has been designed, which has a perfectly rigid in vertical direction and perfectly soft in radial direction. Some three-dimension finite element COSMOS models were performed to analyze their structural strength, stiffness and fatigue life, with an emphasis on the static stress analysis. The load spectra during vacuum vessel operation were also simulated on these models in the view of fatigue design. It was confirmed that the bellows and support had sufficient strength in the designed range of the load conditions. The results showed that the peak stress on bellows was 87 MPa and on the support system was 97 MPa. Now all kinds of bellows and support system have been designed. In order to accumulate some engineering experiences and probe into some molding die and welding technologies, prototypical bellows and support system have been fabricated. At the same time a mechanical testing apparatus was designed for proof tests on the prototypical bellows and support to verify their functional and structure capability. The experimental data indicated that the re-sults of finite element analysis were coincident with experimental test results. It has been proved that the present vacuum vessel's bellows and support system are reasonable and feasible.展开更多
Robust prediction of extreme motions during wind farm support vessel(WFSV)operation is an important safety concern that requires further extensive research as offshore wind energy industry sector widens.In particular,...Robust prediction of extreme motions during wind farm support vessel(WFSV)operation is an important safety concern that requires further extensive research as offshore wind energy industry sector widens.In particular,it is important to study the safety of operation in random sea conditions during WFSV docking against the wind tower,while workers are able to get on the tower.Docking is performed by thrusting vessel fender against wind tower(an alternative docking way by hinging is not studied here).In this paper,the finite element software AQWA has been used to analyze vessel response due to hydrodynamic wave loads,acting on a specific maintenance ship under actual sea conditions.Excessive roll may occur during certain sea conditions,especially in the beam sea,posing a risk to the crew transfer operation.The Bohai Sea is the area of diverse industrial activities such as offshore oil production,wave and wind power generation,etc.This paper advocates a novel method for estimating extreme roll statistics,based on Monte Carlo simulations(or measurements).The ACER(averaged conditional exceedance rate)method and its modification are presented in brief detail in Appendix.The proposed methodology provides an accurate extreme value prediction,utilizing available data efficiently.In this study the estimated return level values,obtained by ACER method,are compared with the corresponding return level values obtained by Gumbel method.Based on the overall performance of the proposed method,it is concluded that the ACER method can provide more robust and accurate prediction of the extreme vessel roll.The described approach may be well used at the vessel design stage,while defining optimal boat parameters would minimize potential roll.展开更多
目的研究颅内支撑导管辅助Solitaire支架取栓抽吸技术(SWIM)在急性颅脑大血管闭塞治疗中的效果。方法选取太和县人民医院2020年11月~2022年5月收治的90例急性颅脑大血管闭塞患者,采取随机数字表法分为观察组与对照组,各45例。观察组给予...目的研究颅内支撑导管辅助Solitaire支架取栓抽吸技术(SWIM)在急性颅脑大血管闭塞治疗中的效果。方法选取太和县人民医院2020年11月~2022年5月收治的90例急性颅脑大血管闭塞患者,采取随机数字表法分为观察组与对照组,各45例。观察组给予SWIM取栓术,对照组给予单纯支架取栓术。术后,采用脑梗死溶栓(TICI)治疗分级标准评估血管再通情况;分别于术前及术后1周采用美国国立卫生研究院卒中量表(NIHSS)评估神经缺损情况,Barthel量表评估患者日常生活自理能力;分别于术前及术后1周检测比较两组神经功能指标[神经元特异性烯醇化酶(NSE)、脑源性神经营养因子(BDNF)、S100β蛋白(S100β)]水平;术后随访3个月,采用改良Rankin量表(mRs)评估患者预后,记录两组患者并发症和死亡情况。结果观察组血管再通率(95.56%,4345)明显高于对照组(68.89%,3145),差异有统计学意义(χ^(2)=10.946,P<0.05)。术后1周,观察组NIHSS评分、NSE、S100β水平较对照组低[(5.37±1.09)分vs.(6.24±1.22)分、(6.03±0.92)ng ml vs.(8.18±1.17)ng ml、(0.27±0.07)ng ml vs.(0.35±0.09)ng ml],观察组Barthel评分、BDNF水平较对照组高[(79.06±8.72)分vs.(69.14±8.09)分、(4776.51±508.65)pg ml vs.(4022.39±425.33)pg ml],差异有统计学意义(t=3.567、9.690、4.707、5.594、7.630,P<0.05)。术后3个月,观察组mRs评分低于对照组,差异有统计学意义(χ^(2)=5.344,P<0.05);两组并发症发生率和死亡率近似,差异无统计学意义(χ^(2)=0.549、0.714,P>0.05)。结论SWIM取栓术能够较好恢复急性颅脑大血管闭塞患者的血流灌注,改善其神经缺损,提高其生活自理能力,同时可改善患者预后。展开更多
In the research,a β-hydroxybutyrate and β-hydroxyvalerate copolymer(PHBV)/polylactic acid(PLA)artificial blood vessel was designed and developed,and it was also implanted in vivo for a period of time to observe its ...In the research,a β-hydroxybutyrate and β-hydroxyvalerate copolymer(PHBV)/polylactic acid(PLA)artificial blood vessel was designed and developed,and it was also implanted in vivo for a period of time to observe its biocompatibility and degradation performance.The results showed that the developed PHBV/PLA artificial blood vessel could be used to replace the natural blood vessel,but its degradation rate was too fast and the mechanical supporting force was insufficient.Thus,properties of the PHBV/PLA need to be further improved.展开更多
This paper attempts to estimate diagnostically relevant measure,i.e.,Arteriovenous Ratio with an improved retinal vessel classification using feature ranking strategies and multiple classifiers decision-combination sc...This paper attempts to estimate diagnostically relevant measure,i.e.,Arteriovenous Ratio with an improved retinal vessel classification using feature ranking strategies and multiple classifiers decision-combination scheme.The features exploited for retinal vessel characterization are based on statistical measures of histogram,different filter responses of images and local gradient in-formation.The feature selection process is based on two feature ranking approaches(Pearson Correlation Coefficient technique and Relief-F method)to rank the features followed by use of maximum classification accuracy of three supervised classifiers(κ-Nearest Neighbor,Support Vector Machine and Naïve Bayes)as a threshold for feature subset selection.Retinal vessels are labeled using the selected feature subset and proposed hybrid classification scheme,i.e.,decision fusion of multiple classifiers.The comparative analysis shows an increase in vessel classification accuracy as well as Arteriovenous Ratio calculation performance.The system is tested on three databases,a local dataset of 44 images and two publically available databases,INSPIRE-AVR containing 40 images and VICAVR containing 58 images.The local database also contains images with pathologically diseased structures.The performance of the proposed system is assessed by comparing the experimental results with the gold standard estimations as well as with the results of previous methodologies.Overall,an accuracy of 90.45%,93.90%and 87.82%is achieved in retinal blood vessel separation with 0.0565,0.0650 and 0.0849 mean error in Arte-riovenous Ratio calculation for Local,INSPIRE-AVR and VICAVR dataset,respectively.展开更多
Recent theoretical physics efforts have been focused on the probes for nonlinear pulse waves in,for example,variable-radius arteries.With respect to the nonlinear waves in an artery full of blood with certain aneurysm...Recent theoretical physics efforts have been focused on the probes for nonlinear pulse waves in,for example,variable-radius arteries.With respect to the nonlinear waves in an artery full of blood with certain aneurysm,pulses in a blood vessel,or features in a circulatory system,this paper symbolically computes out an auto-B?cklund transformation via a noncharacteristic movable singular manifold,certain families of the solitonic solutions,as well as a family of the similarity reductions for a variable-coefficient generalized forced–perturbed Korteweg–de Vries–Burgers equation.Aiming,e.g.,at the dynamical radial displacement superimposed on the original static deformation from an arterial wall,our results rely on the axial stretch of the injured artery,blood as an incompressible Newtonian fluid,radius variation along the axial direction or aneurysmal geometry,viscosity of the fluid,thickness of the artery,mass density of the membrane material,mass density of the fluid,strain energy density of the artery,shear modulus,stretch ratio,etc.We also highlight that the shock-wave structures from our solutions agree well with those dusty-plasma-experimentally reported.展开更多
基金This work was supported by the National Meg-Science Engineering Project of the Chinese Gorernment
文摘Vacuum vessel of the HT-7U is a fully welded toroidal structure with a noncircular cross-section nested in the bore of the TF coils. According to the requirement of the physics design, sixteen horizontal ports on outboard mid-plane and thirty-two vertical ports on the top and bottom are designed for diagnostics, plasma heating, current driving, vacuum pumping and gas puffing. Bellows on these port necks are used for flexible components to absorb the relative displacement in radial and vertical directions due to external load, thermal expansion or contrac-tion and assembly tolerance, and also used for isolation of mechanical vibration. For the support system of vacuum vessel it should be not only strong enough to withstand forces acting on the vessel interior components and the vessel itself due to the dead weight and electromagnetic inter-actions during plasma disruption, but also sufficiently flexible to be suited to thermal expansion during baking. In order to solve this contradiction a new kind of low rigid support has been designed, which has a perfectly rigid in vertical direction and perfectly soft in radial direction. Some three-dimension finite element COSMOS models were performed to analyze their structural strength, stiffness and fatigue life, with an emphasis on the static stress analysis. The load spectra during vacuum vessel operation were also simulated on these models in the view of fatigue design. It was confirmed that the bellows and support had sufficient strength in the designed range of the load conditions. The results showed that the peak stress on bellows was 87 MPa and on the support system was 97 MPa. Now all kinds of bellows and support system have been designed. In order to accumulate some engineering experiences and probe into some molding die and welding technologies, prototypical bellows and support system have been fabricated. At the same time a mechanical testing apparatus was designed for proof tests on the prototypical bellows and support to verify their functional and structure capability. The experimental data indicated that the re-sults of finite element analysis were coincident with experimental test results. It has been proved that the present vacuum vessel's bellows and support system are reasonable and feasible.
文摘Robust prediction of extreme motions during wind farm support vessel(WFSV)operation is an important safety concern that requires further extensive research as offshore wind energy industry sector widens.In particular,it is important to study the safety of operation in random sea conditions during WFSV docking against the wind tower,while workers are able to get on the tower.Docking is performed by thrusting vessel fender against wind tower(an alternative docking way by hinging is not studied here).In this paper,the finite element software AQWA has been used to analyze vessel response due to hydrodynamic wave loads,acting on a specific maintenance ship under actual sea conditions.Excessive roll may occur during certain sea conditions,especially in the beam sea,posing a risk to the crew transfer operation.The Bohai Sea is the area of diverse industrial activities such as offshore oil production,wave and wind power generation,etc.This paper advocates a novel method for estimating extreme roll statistics,based on Monte Carlo simulations(or measurements).The ACER(averaged conditional exceedance rate)method and its modification are presented in brief detail in Appendix.The proposed methodology provides an accurate extreme value prediction,utilizing available data efficiently.In this study the estimated return level values,obtained by ACER method,are compared with the corresponding return level values obtained by Gumbel method.Based on the overall performance of the proposed method,it is concluded that the ACER method can provide more robust and accurate prediction of the extreme vessel roll.The described approach may be well used at the vessel design stage,while defining optimal boat parameters would minimize potential roll.
文摘目的研究颅内支撑导管辅助Solitaire支架取栓抽吸技术(SWIM)在急性颅脑大血管闭塞治疗中的效果。方法选取太和县人民医院2020年11月~2022年5月收治的90例急性颅脑大血管闭塞患者,采取随机数字表法分为观察组与对照组,各45例。观察组给予SWIM取栓术,对照组给予单纯支架取栓术。术后,采用脑梗死溶栓(TICI)治疗分级标准评估血管再通情况;分别于术前及术后1周采用美国国立卫生研究院卒中量表(NIHSS)评估神经缺损情况,Barthel量表评估患者日常生活自理能力;分别于术前及术后1周检测比较两组神经功能指标[神经元特异性烯醇化酶(NSE)、脑源性神经营养因子(BDNF)、S100β蛋白(S100β)]水平;术后随访3个月,采用改良Rankin量表(mRs)评估患者预后,记录两组患者并发症和死亡情况。结果观察组血管再通率(95.56%,4345)明显高于对照组(68.89%,3145),差异有统计学意义(χ^(2)=10.946,P<0.05)。术后1周,观察组NIHSS评分、NSE、S100β水平较对照组低[(5.37±1.09)分vs.(6.24±1.22)分、(6.03±0.92)ng ml vs.(8.18±1.17)ng ml、(0.27±0.07)ng ml vs.(0.35±0.09)ng ml],观察组Barthel评分、BDNF水平较对照组高[(79.06±8.72)分vs.(69.14±8.09)分、(4776.51±508.65)pg ml vs.(4022.39±425.33)pg ml],差异有统计学意义(t=3.567、9.690、4.707、5.594、7.630,P<0.05)。术后3个月,观察组mRs评分低于对照组,差异有统计学意义(χ^(2)=5.344,P<0.05);两组并发症发生率和死亡率近似,差异无统计学意义(χ^(2)=0.549、0.714,P>0.05)。结论SWIM取栓术能够较好恢复急性颅脑大血管闭塞患者的血流灌注,改善其神经缺损,提高其生活自理能力,同时可改善患者预后。
基金"111 Project" Biomedical Textile Materials Science and Technology,China(No.B07024)
文摘In the research,a β-hydroxybutyrate and β-hydroxyvalerate copolymer(PHBV)/polylactic acid(PLA)artificial blood vessel was designed and developed,and it was also implanted in vivo for a period of time to observe its biocompatibility and degradation performance.The results showed that the developed PHBV/PLA artificial blood vessel could be used to replace the natural blood vessel,but its degradation rate was too fast and the mechanical supporting force was insufficient.Thus,properties of the PHBV/PLA need to be further improved.
文摘This paper attempts to estimate diagnostically relevant measure,i.e.,Arteriovenous Ratio with an improved retinal vessel classification using feature ranking strategies and multiple classifiers decision-combination scheme.The features exploited for retinal vessel characterization are based on statistical measures of histogram,different filter responses of images and local gradient in-formation.The feature selection process is based on two feature ranking approaches(Pearson Correlation Coefficient technique and Relief-F method)to rank the features followed by use of maximum classification accuracy of three supervised classifiers(κ-Nearest Neighbor,Support Vector Machine and Naïve Bayes)as a threshold for feature subset selection.Retinal vessels are labeled using the selected feature subset and proposed hybrid classification scheme,i.e.,decision fusion of multiple classifiers.The comparative analysis shows an increase in vessel classification accuracy as well as Arteriovenous Ratio calculation performance.The system is tested on three databases,a local dataset of 44 images and two publically available databases,INSPIRE-AVR containing 40 images and VICAVR containing 58 images.The local database also contains images with pathologically diseased structures.The performance of the proposed system is assessed by comparing the experimental results with the gold standard estimations as well as with the results of previous methodologies.Overall,an accuracy of 90.45%,93.90%and 87.82%is achieved in retinal blood vessel separation with 0.0565,0.0650 and 0.0849 mean error in Arte-riovenous Ratio calculation for Local,INSPIRE-AVR and VICAVR dataset,respectively.
基金supported by the National Natural Science Foundation of China under Grant Nos.11871116 and 11772017the Fundamental Research Funds for the Central Universities of China under Grant No.2019XD-A11.
文摘Recent theoretical physics efforts have been focused on the probes for nonlinear pulse waves in,for example,variable-radius arteries.With respect to the nonlinear waves in an artery full of blood with certain aneurysm,pulses in a blood vessel,or features in a circulatory system,this paper symbolically computes out an auto-B?cklund transformation via a noncharacteristic movable singular manifold,certain families of the solitonic solutions,as well as a family of the similarity reductions for a variable-coefficient generalized forced–perturbed Korteweg–de Vries–Burgers equation.Aiming,e.g.,at the dynamical radial displacement superimposed on the original static deformation from an arterial wall,our results rely on the axial stretch of the injured artery,blood as an incompressible Newtonian fluid,radius variation along the axial direction or aneurysmal geometry,viscosity of the fluid,thickness of the artery,mass density of the membrane material,mass density of the fluid,strain energy density of the artery,shear modulus,stretch ratio,etc.We also highlight that the shock-wave structures from our solutions agree well with those dusty-plasma-experimentally reported.
