目的本研究旨在评估宫颈机能不全(cervical insufficiency,CI)与自发性早产(spontaneous preterm birth,SPB)之间的关联,并探讨宫颈剪切波弹性成像(shear wave elasticity,SWE)、宫颈长度(cervical length,CL)和宫颈前角(anterior cervi...目的本研究旨在评估宫颈机能不全(cervical insufficiency,CI)与自发性早产(spontaneous preterm birth,SPB)之间的关联,并探讨宫颈剪切波弹性成像(shear wave elasticity,SWE)、宫颈长度(cervical length,CL)和宫颈前角(anterior cervical angle,ACA)在预测CI引起的SPB中的应用价值。方法本研究纳入了2023年6月至2024年1月期间在南通大学附属医院及江南大学附属妇产医院产前门诊就诊或住院治疗的786例孕妇,其中足月组723例孕妇,早产组63例孕妇。使用迈瑞Resona R9 Pro/Eagus R9s超声仪,配备剪切波弹性成像软件,进行宫颈SWEI、CL和ACA的测量。此外,按照受检孕周将孕妇分为19~23^(+6)周、24~27^(+6)周、28~33^(+6)周、34~36^(+6)周4组,评估孕周与超声参数的关系。结果早产组孕妇的CL平均为25.42 mm,显著低于足月组的29.71 mm(P<0.001)。ACA在早产组平均为121°,高于足月组的99°(P<0.001)。宫颈各部位的SWE值在早产组也显著低于足月组:外口前唇(AE)为6.47 k Pa对比9.91 k Pa(P<0.001)、内口前唇(AI)为10.98 k Pa对比18.62 k Pa(P<0.001)、内口后唇(PI)为11.32 k Pa对比21.09 k Pa(P<0.001)、外口后唇(PE)为8.16 k Pa对比13.24 k Pa(P<0.001)。CL与孕周存在显著的负相关(r=-0.278,P=0.001)。联合预测指标在预测早产方面显示出较高的准确性和特异性,曲线下面积(AUC)达到0.952,灵敏度和特异度分别为95%和86%。结论宫颈SWE、CL和ACA的联合使用可以显著提高对CI导致SPB的预测效能,可以为临床医生提供了一个更全面、准确的工具,以识别高危孕妇并及时采取干预措施,减少早产的发生,改善母婴预后。展开更多
Quick and reliable identification of the traffic state is of critical importance to traffic control systems, especially when spillovers appear. Firstly, a calculation method for the occupancy per cycle under different...Quick and reliable identification of the traffic state is of critical importance to traffic control systems, especially when spillovers appear. Firstly, a calculation method for the occupancy per cycle under different traffic conditions were presented, based on the relationship between the three basic traffic flow parameters, speed, traffic flow and density. Secondly, the times at which the stopping and starting waves approach a loop detector were confirmed using the traffic wave models modified by a kinematic equation. Then, the threshold of occupancy, which characterizes the appearance of spillovers, was determined by the premise that the stopping and starting waves had the same speed. At last, the accuracy and usability of the new method were verified by VISSIM simulation, using the ratio of misjudgment as the evaluation index. The results show that the ratio of misjudgment of the new method is about 11.36% compared to 17.65% of the previous method.展开更多
Compression ratio is significant for cellular structures on energy absorption. In the present work, theoretical formulas to determine the initial densification strain of honeycomb structure were put forward by means o...Compression ratio is significant for cellular structures on energy absorption. In the present work, theoretical formulas to determine the initial densification strain of honeycomb structure were put forward by means of minimum energy principle. Detailed densification strain points were identified, with full fold model for kinds of specimens. To validate, corresponding numerical simulations were carried out with explicit finite element method. Excellent agreement in terms of initial densification stain point has been observed between the theoretical calculation and numerical simulation. The results show that: (1) a different honeycomb structure has different initial densification strain point, and its geometric configuration of cells plays an evident role on densification; (2) half-wave length of the wrinkle of honeycomb in folding process significantly influences on the densification strain point; (3) the initial densification point is an decreasing power function of the ratio of foil thickness to cell length, with the exponent 2/3. These achievements provide important references for design in cellular energy absorption devices.展开更多
Semiconductor pigment of Cd-Zn-S is synthesized through the solid state reaction method and its structure and surface morphology is characterized by X-ray diffraction (XRD) and scanning electron microscope(SEM). It is...Semiconductor pigment of Cd-Zn-S is synthesized through the solid state reaction method and its structure and surface morphology is characterized by X-ray diffraction (XRD) and scanning electron microscope(SEM). It is demonstrated that the crystal lattice of the product is hexagonal. When the heat treatment temperature increases, the distortion of crystal lattice reduces. The samples annealed at different temperatures agglomerate to different degrees while the one annealed at higher temperature agglomerates clearly. The infrared emissivity of Cd-Zn-S at two window-bands of 3-5 μm and 8-14 μm is researched. The researched result shows that the infrared emissivity of Cd-Zn-S in 8-14 μm wave bands is much higher than that in 3-5 μm wave bands. The infrared emissivity decreases with the increasing of heat treatment temperature, which reason is that with the increasing of temperature, the infrared absorption decreases and the scatter by the particles rises.展开更多
文摘目的本研究旨在评估宫颈机能不全(cervical insufficiency,CI)与自发性早产(spontaneous preterm birth,SPB)之间的关联,并探讨宫颈剪切波弹性成像(shear wave elasticity,SWE)、宫颈长度(cervical length,CL)和宫颈前角(anterior cervical angle,ACA)在预测CI引起的SPB中的应用价值。方法本研究纳入了2023年6月至2024年1月期间在南通大学附属医院及江南大学附属妇产医院产前门诊就诊或住院治疗的786例孕妇,其中足月组723例孕妇,早产组63例孕妇。使用迈瑞Resona R9 Pro/Eagus R9s超声仪,配备剪切波弹性成像软件,进行宫颈SWEI、CL和ACA的测量。此外,按照受检孕周将孕妇分为19~23^(+6)周、24~27^(+6)周、28~33^(+6)周、34~36^(+6)周4组,评估孕周与超声参数的关系。结果早产组孕妇的CL平均为25.42 mm,显著低于足月组的29.71 mm(P<0.001)。ACA在早产组平均为121°,高于足月组的99°(P<0.001)。宫颈各部位的SWE值在早产组也显著低于足月组:外口前唇(AE)为6.47 k Pa对比9.91 k Pa(P<0.001)、内口前唇(AI)为10.98 k Pa对比18.62 k Pa(P<0.001)、内口后唇(PI)为11.32 k Pa对比21.09 k Pa(P<0.001)、外口后唇(PE)为8.16 k Pa对比13.24 k Pa(P<0.001)。CL与孕周存在显著的负相关(r=-0.278,P=0.001)。联合预测指标在预测早产方面显示出较高的准确性和特异性,曲线下面积(AUC)达到0.952,灵敏度和特异度分别为95%和86%。结论宫颈SWE、CL和ACA的联合使用可以显著提高对CI导致SPB的预测效能,可以为临床医生提供了一个更全面、准确的工具,以识别高危孕妇并及时采取干预措施,减少早产的发生,改善母婴预后。
基金Project(2011AA110304) supported by the National High Technology Research and Development Program of China
文摘Quick and reliable identification of the traffic state is of critical importance to traffic control systems, especially when spillovers appear. Firstly, a calculation method for the occupancy per cycle under different traffic conditions were presented, based on the relationship between the three basic traffic flow parameters, speed, traffic flow and density. Secondly, the times at which the stopping and starting waves approach a loop detector were confirmed using the traffic wave models modified by a kinematic equation. Then, the threshold of occupancy, which characterizes the appearance of spillovers, was determined by the premise that the stopping and starting waves had the same speed. At last, the accuracy and usability of the new method were verified by VISSIM simulation, using the ratio of misjudgment as the evaluation index. The results show that the ratio of misjudgment of the new method is about 11.36% compared to 17.65% of the previous method.
基金Project(51505502)supported by the National Natural Science Foundation of ChinaProject(2015BAG13B01)supported by the National Key Technology Support Program,China+1 种基金Project(ZZYJKT2017-09)supported by the State Key Laboratory of High Performance Complex Manufacturing,ChinaProject supported by the Open End Fund for the Valuable and Precision Instrument of Central Sonth University,China
文摘Compression ratio is significant for cellular structures on energy absorption. In the present work, theoretical formulas to determine the initial densification strain of honeycomb structure were put forward by means of minimum energy principle. Detailed densification strain points were identified, with full fold model for kinds of specimens. To validate, corresponding numerical simulations were carried out with explicit finite element method. Excellent agreement in terms of initial densification stain point has been observed between the theoretical calculation and numerical simulation. The results show that: (1) a different honeycomb structure has different initial densification strain point, and its geometric configuration of cells plays an evident role on densification; (2) half-wave length of the wrinkle of honeycomb in folding process significantly influences on the densification strain point; (3) the initial densification point is an decreasing power function of the ratio of foil thickness to cell length, with the exponent 2/3. These achievements provide important references for design in cellular energy absorption devices.
基金Chinese Postdoctoral Fund (2006040931)National Natural Science Foundation of China (90505008)
文摘Semiconductor pigment of Cd-Zn-S is synthesized through the solid state reaction method and its structure and surface morphology is characterized by X-ray diffraction (XRD) and scanning electron microscope(SEM). It is demonstrated that the crystal lattice of the product is hexagonal. When the heat treatment temperature increases, the distortion of crystal lattice reduces. The samples annealed at different temperatures agglomerate to different degrees while the one annealed at higher temperature agglomerates clearly. The infrared emissivity of Cd-Zn-S at two window-bands of 3-5 μm and 8-14 μm is researched. The researched result shows that the infrared emissivity of Cd-Zn-S in 8-14 μm wave bands is much higher than that in 3-5 μm wave bands. The infrared emissivity decreases with the increasing of heat treatment temperature, which reason is that with the increasing of temperature, the infrared absorption decreases and the scatter by the particles rises.
