Microseismic/acoustic emission(MS/AE)source localization method is crucial for predicting and controlling of potentially dangerous sources of complex structures.However,the locating errors induced by both the irregula...Microseismic/acoustic emission(MS/AE)source localization method is crucial for predicting and controlling of potentially dangerous sources of complex structures.However,the locating errors induced by both the irregular structure and pre-measured velocity are poorly understood in existing methods.To meet the high-accuracy locating requirements in complex three-dimensional hole-containing structures,a velocity-free MS/AE source location method is developed in this paper.It avoids manual repetitive training by using equidistant grid points to search the path,which introduces A*search algorithm and uses grid points to accommodate complex structures with irregular holes.It also takes advantage of the velocity-free source location method.To verify the validity of the proposed method,lead-breaking tests were performed on a cubic concrete test specimen with a size of 10 cm10 cm10 cm.It was cut out into a cylindrical empty space with a size of/6cm10 cm.Based on the arrivals,the classical Geiger method and the proposed method are used to locate lead-breaking sources.Results show that the locating error of the proposed method is 1.20 cm,which is less than 2.02 cm of the Geiger method.Hence,the proposed method can effectively locate sources in the complex three-dimensional structure with holes and achieve higher precision requirements.展开更多
【目的】探讨单孔与三孔胸腔镜肺叶切除术治疗早期非小细胞肺癌的疗效、安全性及对机体应激反应的影响。【方法】选取2015年1月至2017年3月本院收治的早期非小细胞肺癌患者104例,按照随机数字表法分为观察组和对照组,各52例,观察组采用...【目的】探讨单孔与三孔胸腔镜肺叶切除术治疗早期非小细胞肺癌的疗效、安全性及对机体应激反应的影响。【方法】选取2015年1月至2017年3月本院收治的早期非小细胞肺癌患者104例,按照随机数字表法分为观察组和对照组,各52例,观察组采用单孔胸腔镜手术,对照组采用三孔胸腔镜手术。比较2组患者手术指标、术后恢复情况、疼痛评分及应激反应指标情况,记录2组患者术后出现并发症情况。【结果】观察组在引流管留置时间、术后住院时间方面优于对照组,差异显著(P<0.05);2组患者术后1、2、3 d视觉模拟量表(visual analog scale,VAS)评分逐渐降低,观察组各时间点VAS评分优于对照组,差异显著(P<0.05);2组患者术后1 d皮质醇(cortisol,Cor)、生长激素、前列腺素E2(prostaglandin E2,PGE2)水平明显升高,术后3 d Cor、生长激素、PGE2水平低于术后1 d,观察组术后1、3 d上述指标水平低于对照组,差异显著(P<0.05);2组患者术后并发症发生率比较差异无统计学意义(P>0.05)。【结论】与传统三孔胸腔镜术式比较,单孔胸腔镜肺叶切除术能够更好地缩短患者术后带管时间及住院时间,减轻术后应激反应,更有利于患者康复。展开更多
This paper employes variable function method and the technique of conformal mappingto discuss the anti-plane problem of a circular hole with three unequal cracksin a one-dimensional （1D） hexagonal piezoelectric quas...This paper employes variable function method and the technique of conformal mappingto discuss the anti-plane problem of a circular hole with three unequal cracksin a one-dimensional （1D） hexagonal piezoelectric quasicrystal. Based on the piezoelectricityfundamental equations of quasicrystal materials and the symmetry of1D hexagonal quasicrystal and its linear piezoelectricity effect, 1D hexagonal quasicrystalcontrol equations of anti-plane problem are derived. Applying Cauchyintegral formula, the analytical expressions for the crack tip filed intensity factorsare presented with the assumption that the crack are electrical impermeable andelectrical permeable. With the variation of the hole-size and the crack length, someof the new model of crack are obtained. In the absence of the electric load, theresults match with the classical ones. The numerical results indicate the effects ofgeometric parameters on the field intensity factors. It is verified that the horizontalcrack length and the circle radius can easily promote crack growth. Researchon such issues will provide reliable theoretical value for the engineering materialspreparation and application.展开更多
目的探讨单孔法与三孔法腹腔镜疝修补术治疗腹股沟疝的疗效差异。方法回顾性地收集自2011年6月至2016年6月于我科就诊并行腹腔镜腹股沟疝修补术的205例病人的临床资料。按照拟行手术方式不同(是否中转更改手术方式不作为影响分组因素),...目的探讨单孔法与三孔法腹腔镜疝修补术治疗腹股沟疝的疗效差异。方法回顾性地收集自2011年6月至2016年6月于我科就诊并行腹腔镜腹股沟疝修补术的205例病人的临床资料。按照拟行手术方式不同(是否中转更改手术方式不作为影响分组因素),将本次研究纳入的205例病人分为单孔组129例和三孔组76例,比较组间病人性别构成、年龄分布、平均体质量指数(body mass index,BMI)、手术时间、中转手术率(单孔法转三孔法或腹腔镜法转传统开放手术)以及术后并发症发生率的差异。结果组间一般资料比较显示,两组病人性别构成、平均年龄、平均BMI及疝类型(单侧、双侧)差异均无统计学意义(均P>0.05);单孔组手术时间为(55.3±22.8)min,三孔组为(49.4±14.9)min,组间差异无统计学意义(P=0.06);单孔组无中转行三孔法手术病例,两组中转行传统开放手术率基本接近,组间差异无统计学意义(P=0.98);两组术后尿潴留、切口感染发生率差异无统计学意义(均P>0.05),而单孔组病人术后疼痛程度相对较轻,术后住院时间相对较短,与三孔组相比,差异均有统计学意义(均P<0.05);两组病人总体住院费用,单孔组为(2.21±0.65)万元,三孔组为(2.55±0.89)万元,差异无统计学意义(P>0.05);两组病人术后血肿形成、皮下气肿、慢性疼痛发生率相比,差异均无统计学意义(均P>0.05),但与三孔组相比,单孔组的上述并发症发生率均有降低趋势。结论单孔法腹腔镜腹股沟疝修补术是一种临床应用相对安全且卫生经济学指标表现更具优势的新兴微创手术方式,更好地吻合了加速康复外科的理念,值得临床进一步研究证实。展开更多
The paper presents analysis of the performance and the internal flow behaviour in the vaned diffuser of a radial flow pump using PIV(particle image velocimetry)and pressure probe traverses.PIV measurements have alread...The paper presents analysis of the performance and the internal flow behaviour in the vaned diffuser of a radial flow pump using PIV(particle image velocimetry)and pressure probe traverses.PIV measurements have already been performed at middle height inside one diffuser channel passage for a given speed of rotation and various mass flow rates.These results have been already presented in several previous communications.New experiments have been performed using a three-hole pressure probe traverses from hub to shroud diffuser width at different radial locations between the two diffuser geometrical throats.Numerical simulations are also realized with the commercial codes Star CCM+7.02.011 and CFX.Frozen rotor and fully unsteady calculations of the whole pump have been performed.Comparisons between numerical results,previous experimental PIV results and new probe traverses one's are presented and discussed for one mass flow rate.In this respect,a first attempt to take into account fluid leakages between the rotating and fixed part of the pump has been checked since it may affects the real flow structure inside the diffuser.展开更多
Vertical three-dimensional(3D)integration is a highly attractive strategy to integrate a large number of transistor devices per unit area.This approach has emerged to accommodate the higher demand of data processing c...Vertical three-dimensional(3D)integration is a highly attractive strategy to integrate a large number of transistor devices per unit area.This approach has emerged to accommodate the higher demand of data processing capability and to circumvent the scaling limitation.A huge number of research efforts have been attempted to demonstrate vertically stacked electronics in the last two decades.In this review,we revisit materials and devices for the vertically integrated electronics with an emphasis on the emerging semiconductor materials that can be processable by bottom-up fabrication methods,which are suitable for future flexible and wearable electronics.The vertically stacked integrated circuits are reviewed based on the semiconductor materials:organic semiconductors,carbon nanotubes,metal oxide semiconductors,and atomically thin two-dimensional materials including transi-tion metal dichalcogenides.The features,device performance,and fabrication methods for 3D integration of the transistor based on each semiconductor are discussed.Moreover,we highlight recent advances that can be important milestones in the vertically integrated elec-tronics including advanced integrated circuits,sensors,and display systems.There are remaining challenges to overcome;however,we believe that the vertical 3D integration based on emerging semiconductor materials and devices can be a promising strategy for future electronics.展开更多
The purpose of this paper is to study the critical sand starting velocity and transformation law of flow pattern based on gas-water-sand three-phase flow in an inclined pipe.Firstly,the indoor simulation experiment sy...The purpose of this paper is to study the critical sand starting velocity and transformation law of flow pattern based on gas-water-sand three-phase flow in an inclined pipe.Firstly,the indoor simulation experiment system of gas-water-sand three-phase flow was used to test the conversion law of flow pattern based upon the different gas void fraction.Secondly,the influence of slug bubbles on sand migration was investigated according to distinctive hole deviation angles,gas void fraction and sand concentration.Finally,the critical sand starting velocity was tested based on dissimilar hole deviation angles,gas void fraction,sand concentration and sand particle size,and then the influence of the abovementioned key parameters on the sand starting velocity was debated based on the force analysis of the sand particles.The experimental results illustrated that when the gas void fraction was less than 5%,it was bubbly flow.When it increased from 5%to 30%,the bubbly flow and slug flow coexisted.When it was between 30%and 50%,the slug flow and agitated flow coexisted.When it reached 50%,it was agitated flow.Providing that the hole deviation angle was 90°,the phenomenon of overall migration and wavelike migration on the surface of sand bed was observed.On the contrary,the phenomenon of rolling and jumping migration was recognized.The critical sand starting velocity was positively correlated with the hole deviation angle and sand particle size,but negatively associated with the gas void fraction and sand concentration.This research can provide a certain reference for sand-starting production in the field of petroleum engineering.展开更多
目的比较三孔免钛夹腹腔镜胆囊切除术与开腹胆囊切除术的临床治疗效果。方法将104例需行胆囊切除手术的患者根据治疗方法分为对照组和观察组,各52例。对照组采用开腹胆囊切除术治疗,观察组采用三孔免钛夹腹腔镜胆囊切除术治疗。比较两...目的比较三孔免钛夹腹腔镜胆囊切除术与开腹胆囊切除术的临床治疗效果。方法将104例需行胆囊切除手术的患者根据治疗方法分为对照组和观察组,各52例。对照组采用开腹胆囊切除术治疗,观察组采用三孔免钛夹腹腔镜胆囊切除术治疗。比较两组患者的临床疗效。结果观察组患者手术时间、术中出血量、住院时间、胃肠道功能恢复时间、下床活动时间均优于对照组患者(P<0.05)。两组患者治疗后1、7 d CRP水平均高于治疗前(P<0.05);治疗后7 d两组CRP水平低于治疗后1 d,且观察组低于对照组(P<0.05)。观察组不良反应发生率低于对照组(P<0.05)。结论三孔免钛夹腹腔镜胆囊切除治疗胆囊疾病的临床效果优,不良反应少,值得临床推广应用。展开更多
基金The authors wish to acknowledge financial support from the National Natural Science Foundation of China(51822407 and 51774327)Natural Science Foundation of Hunan Province in China(2018JJ1037)Innovation Driven project of Central South University(2020CX014).
文摘Microseismic/acoustic emission(MS/AE)source localization method is crucial for predicting and controlling of potentially dangerous sources of complex structures.However,the locating errors induced by both the irregular structure and pre-measured velocity are poorly understood in existing methods.To meet the high-accuracy locating requirements in complex three-dimensional hole-containing structures,a velocity-free MS/AE source location method is developed in this paper.It avoids manual repetitive training by using equidistant grid points to search the path,which introduces A*search algorithm and uses grid points to accommodate complex structures with irregular holes.It also takes advantage of the velocity-free source location method.To verify the validity of the proposed method,lead-breaking tests were performed on a cubic concrete test specimen with a size of 10 cm10 cm10 cm.It was cut out into a cylindrical empty space with a size of/6cm10 cm.Based on the arrivals,the classical Geiger method and the proposed method are used to locate lead-breaking sources.Results show that the locating error of the proposed method is 1.20 cm,which is less than 2.02 cm of the Geiger method.Hence,the proposed method can effectively locate sources in the complex three-dimensional structure with holes and achieve higher precision requirements.
文摘【目的】探讨单孔与三孔胸腔镜肺叶切除术治疗早期非小细胞肺癌的疗效、安全性及对机体应激反应的影响。【方法】选取2015年1月至2017年3月本院收治的早期非小细胞肺癌患者104例,按照随机数字表法分为观察组和对照组,各52例,观察组采用单孔胸腔镜手术,对照组采用三孔胸腔镜手术。比较2组患者手术指标、术后恢复情况、疼痛评分及应激反应指标情况,记录2组患者术后出现并发症情况。【结果】观察组在引流管留置时间、术后住院时间方面优于对照组,差异显著(P<0.05);2组患者术后1、2、3 d视觉模拟量表(visual analog scale,VAS)评分逐渐降低,观察组各时间点VAS评分优于对照组,差异显著(P<0.05);2组患者术后1 d皮质醇(cortisol,Cor)、生长激素、前列腺素E2(prostaglandin E2,PGE2)水平明显升高,术后3 d Cor、生长激素、PGE2水平低于术后1 d,观察组术后1、3 d上述指标水平低于对照组,差异显著(P<0.05);2组患者术后并发症发生率比较差异无统计学意义(P>0.05)。【结论】与传统三孔胸腔镜术式比较,单孔胸腔镜肺叶切除术能够更好地缩短患者术后带管时间及住院时间,减轻术后应激反应,更有利于患者康复。
文摘This paper employes variable function method and the technique of conformal mappingto discuss the anti-plane problem of a circular hole with three unequal cracksin a one-dimensional （1D） hexagonal piezoelectric quasicrystal. Based on the piezoelectricityfundamental equations of quasicrystal materials and the symmetry of1D hexagonal quasicrystal and its linear piezoelectricity effect, 1D hexagonal quasicrystalcontrol equations of anti-plane problem are derived. Applying Cauchyintegral formula, the analytical expressions for the crack tip filed intensity factorsare presented with the assumption that the crack are electrical impermeable andelectrical permeable. With the variation of the hole-size and the crack length, someof the new model of crack are obtained. In the absence of the electric load, theresults match with the classical ones. The numerical results indicate the effects ofgeometric parameters on the field intensity factors. It is verified that the horizontalcrack length and the circle radius can easily promote crack growth. Researchon such issues will provide reliable theoretical value for the engineering materialspreparation and application.
文摘目的探讨单孔法与三孔法腹腔镜疝修补术治疗腹股沟疝的疗效差异。方法回顾性地收集自2011年6月至2016年6月于我科就诊并行腹腔镜腹股沟疝修补术的205例病人的临床资料。按照拟行手术方式不同(是否中转更改手术方式不作为影响分组因素),将本次研究纳入的205例病人分为单孔组129例和三孔组76例,比较组间病人性别构成、年龄分布、平均体质量指数(body mass index,BMI)、手术时间、中转手术率(单孔法转三孔法或腹腔镜法转传统开放手术)以及术后并发症发生率的差异。结果组间一般资料比较显示,两组病人性别构成、平均年龄、平均BMI及疝类型(单侧、双侧)差异均无统计学意义(均P>0.05);单孔组手术时间为(55.3±22.8)min,三孔组为(49.4±14.9)min,组间差异无统计学意义(P=0.06);单孔组无中转行三孔法手术病例,两组中转行传统开放手术率基本接近,组间差异无统计学意义(P=0.98);两组术后尿潴留、切口感染发生率差异无统计学意义(均P>0.05),而单孔组病人术后疼痛程度相对较轻,术后住院时间相对较短,与三孔组相比,差异均有统计学意义(均P<0.05);两组病人总体住院费用,单孔组为(2.21±0.65)万元,三孔组为(2.55±0.89)万元,差异无统计学意义(P>0.05);两组病人术后血肿形成、皮下气肿、慢性疼痛发生率相比,差异均无统计学意义(均P>0.05),但与三孔组相比,单孔组的上述并发症发生率均有降低趋势。结论单孔法腹腔镜腹股沟疝修补术是一种临床应用相对安全且卫生经济学指标表现更具优势的新兴微创手术方式,更好地吻合了加速康复外科的理念,值得临床进一步研究证实。
文摘The paper presents analysis of the performance and the internal flow behaviour in the vaned diffuser of a radial flow pump using PIV(particle image velocimetry)and pressure probe traverses.PIV measurements have already been performed at middle height inside one diffuser channel passage for a given speed of rotation and various mass flow rates.These results have been already presented in several previous communications.New experiments have been performed using a three-hole pressure probe traverses from hub to shroud diffuser width at different radial locations between the two diffuser geometrical throats.Numerical simulations are also realized with the commercial codes Star CCM+7.02.011 and CFX.Frozen rotor and fully unsteady calculations of the whole pump have been performed.Comparisons between numerical results,previous experimental PIV results and new probe traverses one's are presented and discussed for one mass flow rate.In this respect,a first attempt to take into account fluid leakages between the rotating and fixed part of the pump has been checked since it may affects the real flow structure inside the diffuser.
基金This work was supported by the National Research Foundation of Korea(NRF)grants by the Korean Government(MSIT)(NRF-2021R1A6A3A14038580,NRF-2020R1A2C1101647)This work was supported by the Technology Innovation Program(00144300,Interface Technology of 3D Stacked Heterogeneous System for SCM-based Process-in-Memory)funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea).
文摘Vertical three-dimensional(3D)integration is a highly attractive strategy to integrate a large number of transistor devices per unit area.This approach has emerged to accommodate the higher demand of data processing capability and to circumvent the scaling limitation.A huge number of research efforts have been attempted to demonstrate vertically stacked electronics in the last two decades.In this review,we revisit materials and devices for the vertically integrated electronics with an emphasis on the emerging semiconductor materials that can be processable by bottom-up fabrication methods,which are suitable for future flexible and wearable electronics.The vertically stacked integrated circuits are reviewed based on the semiconductor materials:organic semiconductors,carbon nanotubes,metal oxide semiconductors,and atomically thin two-dimensional materials including transi-tion metal dichalcogenides.The features,device performance,and fabrication methods for 3D integration of the transistor based on each semiconductor are discussed.Moreover,we highlight recent advances that can be important milestones in the vertically integrated elec-tronics including advanced integrated circuits,sensors,and display systems.There are remaining challenges to overcome;however,we believe that the vertical 3D integration based on emerging semiconductor materials and devices can be a promising strategy for future electronics.
基金supporting by the Youth Program of National Natural Science Foundation of China(52104012)the China Postdoctoral Science Foundation(2021M693494)+2 种基金the Key Program of the National Natural Science Foundation of China(51734010)the Key Natural Science Projects of Scientific Research Plan in Colleges and Universities of Xinjiang Uygur Autonomous Region(XJEDU2021I028)the Strategic Cooperation Technology Projects of CNPC and CUPB(ZLZX2020-01-01)
文摘The purpose of this paper is to study the critical sand starting velocity and transformation law of flow pattern based on gas-water-sand three-phase flow in an inclined pipe.Firstly,the indoor simulation experiment system of gas-water-sand three-phase flow was used to test the conversion law of flow pattern based upon the different gas void fraction.Secondly,the influence of slug bubbles on sand migration was investigated according to distinctive hole deviation angles,gas void fraction and sand concentration.Finally,the critical sand starting velocity was tested based on dissimilar hole deviation angles,gas void fraction,sand concentration and sand particle size,and then the influence of the abovementioned key parameters on the sand starting velocity was debated based on the force analysis of the sand particles.The experimental results illustrated that when the gas void fraction was less than 5%,it was bubbly flow.When it increased from 5%to 30%,the bubbly flow and slug flow coexisted.When it was between 30%and 50%,the slug flow and agitated flow coexisted.When it reached 50%,it was agitated flow.Providing that the hole deviation angle was 90°,the phenomenon of overall migration and wavelike migration on the surface of sand bed was observed.On the contrary,the phenomenon of rolling and jumping migration was recognized.The critical sand starting velocity was positively correlated with the hole deviation angle and sand particle size,but negatively associated with the gas void fraction and sand concentration.This research can provide a certain reference for sand-starting production in the field of petroleum engineering.
文摘目的比较三孔免钛夹腹腔镜胆囊切除术与开腹胆囊切除术的临床治疗效果。方法将104例需行胆囊切除手术的患者根据治疗方法分为对照组和观察组,各52例。对照组采用开腹胆囊切除术治疗,观察组采用三孔免钛夹腹腔镜胆囊切除术治疗。比较两组患者的临床疗效。结果观察组患者手术时间、术中出血量、住院时间、胃肠道功能恢复时间、下床活动时间均优于对照组患者(P<0.05)。两组患者治疗后1、7 d CRP水平均高于治疗前(P<0.05);治疗后7 d两组CRP水平低于治疗后1 d,且观察组低于对照组(P<0.05)。观察组不良反应发生率低于对照组(P<0.05)。结论三孔免钛夹腹腔镜胆囊切除治疗胆囊疾病的临床效果优,不良反应少,值得临床推广应用。
