目前,国内高压直流输电技术分为两类:一是基于ABB、南瑞技术路线的限幅型直流,二是基于SIEMENS、许继技术路线的选择型直流。前者已有成熟机电暂态仿真模型,而后者尚缺乏深入研究,通常以限幅型模型近似代替,仿真结果与实际尚有一定差距...目前,国内高压直流输电技术分为两类:一是基于ABB、南瑞技术路线的限幅型直流,二是基于SIEMENS、许继技术路线的选择型直流。前者已有成熟机电暂态仿真模型,而后者尚缺乏深入研究,通常以限幅型模型近似代替,仿真结果与实际尚有一定差距,难以满足电力系统安全稳定计算的需求。该文在总结直流输电系统机电暂态建模原则的基础上,建立了选择型直流的精细化模型;利用轨迹灵敏度筛选出需校核参数,提出了基于实测数据的关键参数校核方法;并在中国通用的电力系统暂态稳定程序(powersystem department power tools-swing transient,PSD-ST)中开发实现,最后利用厂家电磁暂态仿真结果验证了模型的正确性。该文成果可改善直流控制系统模型缺失、仿真能力受限问题,有效提升机电暂态仿真程序的仿真精度。展开更多
Transparent photoresists with a high refractive index(RI)and high transmittance in visible wavelengths have promising functionalities in optical fields.This work reports a kind of tunable optical material composed of ...Transparent photoresists with a high refractive index(RI)and high transmittance in visible wavelengths have promising functionalities in optical fields.This work reports a kind of tunable optical material composed of titanium dioxide nanoparticles embedded in acrylic resin with a high RI for ultraviolet(UV)-imprint lithography.The hybrid film exhibits a tunable RI of up to 1.67(589 nm)after being cured by UV light,while maintaining both a high transparency of over 98%in the visible light range and a low haze of less than 0.05%.The precision machining of optical microstructures can be imprinted easily and efficiently using the hybrid resin,which acts as a light guide plate(LGP)to guide the light from the side to the top in order to conserve the energy of the display device.These preliminary studies based on both laboratory and commercial experiments pave the way for exploiting the unparalleled optical properties of nanocomposite resins and promoting their industrial application.展开更多
In order to solve the problems of surface runoff increase,water accumulation in rainy days and urban heat island effect,an ecological outdoor ground structure with composite water storage and drainage functions was st...In order to solve the problems of surface runoff increase,water accumulation in rainy days and urban heat island effect,an ecological outdoor ground structure with composite water storage and drainage functions was studied and applied in this paper:Through the comprehensive design of road ground,road inspection well,garden inspection well and drainage pipe network,it can quickly store and drain ground water,alleviate the urban heat island effect,realize plant infiltration irrigation,and achieve the purpose of saving water and energy.展开更多
目的探讨血清肿瘤标志物癌胚抗原和糖类抗原在胃癌腹膜转移中的诊断价值,为胃癌腹膜转移的诊断提供理论依据。方法纳入2014年6月～2017年6月于乐山市人民医院肿瘤科诊治的68例胃癌患者,根据是否发生腹膜转移分为转移组(20例)与非转移组...目的探讨血清肿瘤标志物癌胚抗原和糖类抗原在胃癌腹膜转移中的诊断价值,为胃癌腹膜转移的诊断提供理论依据。方法纳入2014年6月～2017年6月于乐山市人民医院肿瘤科诊治的68例胃癌患者,根据是否发生腹膜转移分为转移组(20例)与非转移组(48例);手术或化疗前采用全自动免疫分析仪检测血清肿瘤标志物癌胚抗原(Carcinoembryonic antigen,CEA)、糖类抗原CA724、CA242、CA211、CA19-9、CA125水平,比较两组各检测指标血清水平、阳性率。进行Logistic回归分析,绘制受试者特征ROC曲线,比较联合检测以及各指标单独检测的诊断效能。结果转移组血清CEA、CA724、CA242、CA211、CA19-9、CA125水平均显著高于非转移组,差异均有统计学意义(P<0.05);转移组血清CA724、CA125、CA211阳性率显著高于非转移组,差异均有统计学意义(P<0.05),血清CEA、CA242、CA19-9阳性率差异无统计学意义(P>0.05);CA724、CA125、CA211联合诊断(Y1)与所有检测指标联合诊断(Y2)ROC曲线下面积(area under the cure,AUC)值均大于单项指标诊断(P<0.05)。结论单项指标中CA125诊断胃癌腹膜转移效能最高,其与CA724、CA211联合诊断可作为胃癌腹膜转移的有效诊断方式。展开更多
文摘目前,国内高压直流输电技术分为两类:一是基于ABB、南瑞技术路线的限幅型直流,二是基于SIEMENS、许继技术路线的选择型直流。前者已有成熟机电暂态仿真模型,而后者尚缺乏深入研究,通常以限幅型模型近似代替,仿真结果与实际尚有一定差距,难以满足电力系统安全稳定计算的需求。该文在总结直流输电系统机电暂态建模原则的基础上,建立了选择型直流的精细化模型;利用轨迹灵敏度筛选出需校核参数,提出了基于实测数据的关键参数校核方法;并在中国通用的电力系统暂态稳定程序(powersystem department power tools-swing transient,PSD-ST)中开发实现,最后利用厂家电磁暂态仿真结果验证了模型的正确性。该文成果可改善直流控制系统模型缺失、仿真能力受限问题,有效提升机电暂态仿真程序的仿真精度。
基金supported by the National Natural Science Foundation of China(22288102 and 22278027).
文摘Transparent photoresists with a high refractive index(RI)and high transmittance in visible wavelengths have promising functionalities in optical fields.This work reports a kind of tunable optical material composed of titanium dioxide nanoparticles embedded in acrylic resin with a high RI for ultraviolet(UV)-imprint lithography.The hybrid film exhibits a tunable RI of up to 1.67(589 nm)after being cured by UV light,while maintaining both a high transparency of over 98%in the visible light range and a low haze of less than 0.05%.The precision machining of optical microstructures can be imprinted easily and efficiently using the hybrid resin,which acts as a light guide plate(LGP)to guide the light from the side to the top in order to conserve the energy of the display device.These preliminary studies based on both laboratory and commercial experiments pave the way for exploiting the unparalleled optical properties of nanocomposite resins and promoting their industrial application.
文摘In order to solve the problems of surface runoff increase,water accumulation in rainy days and urban heat island effect,an ecological outdoor ground structure with composite water storage and drainage functions was studied and applied in this paper:Through the comprehensive design of road ground,road inspection well,garden inspection well and drainage pipe network,it can quickly store and drain ground water,alleviate the urban heat island effect,realize plant infiltration irrigation,and achieve the purpose of saving water and energy.
文摘目的探讨血清肿瘤标志物癌胚抗原和糖类抗原在胃癌腹膜转移中的诊断价值,为胃癌腹膜转移的诊断提供理论依据。方法纳入2014年6月～2017年6月于乐山市人民医院肿瘤科诊治的68例胃癌患者,根据是否发生腹膜转移分为转移组(20例)与非转移组(48例);手术或化疗前采用全自动免疫分析仪检测血清肿瘤标志物癌胚抗原(Carcinoembryonic antigen,CEA)、糖类抗原CA724、CA242、CA211、CA19-9、CA125水平,比较两组各检测指标血清水平、阳性率。进行Logistic回归分析,绘制受试者特征ROC曲线,比较联合检测以及各指标单独检测的诊断效能。结果转移组血清CEA、CA724、CA242、CA211、CA19-9、CA125水平均显著高于非转移组,差异均有统计学意义(P<0.05);转移组血清CA724、CA125、CA211阳性率显著高于非转移组,差异均有统计学意义(P<0.05),血清CEA、CA242、CA19-9阳性率差异无统计学意义(P>0.05);CA724、CA125、CA211联合诊断(Y1)与所有检测指标联合诊断(Y2)ROC曲线下面积(area under the cure,AUC)值均大于单项指标诊断(P<0.05)。结论单项指标中CA125诊断胃癌腹膜转移效能最高,其与CA724、CA211联合诊断可作为胃癌腹膜转移的有效诊断方式。
