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Rigid-flexible coupling dynamic modeling and vibration control for flexible spacecraft based on its global analytical modes
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作者 LIU Lun CAO DengQing WEI Jin 《中国科学:技术科学英文版》 SCIE EI CAS CSCD 2019年第4期608-618,共11页
In this study,we used global analytical modeswfny(GAMs)to develop a rigid-flexible dynamic modeling approach for spacecraft with large flexible appendages(SwLFA).This approach enables the convenient and precise calcul... In this study,we used global analytical modeswfny(GAMs)to develop a rigid-flexible dynamic modeling approach for spacecraft with large flexible appendages(SwLFA).This approach enables the convenient and precise calculation of the natural characteristics for designing an attitude control law for the spacecraft while simultaneously suppressing the active vibration of its flexible appendages.We simplify the flexible spacecraft as a rigid-flexible coupling hub-beam system with tip mass and derive the system’s governing equations of motion based on Hamilton’s principle.By solving the linearized form of those equations with their associated boundary conditions,we obtain the frequencies as well as the corresponding GAMs of flexible spacecraft,which we use to discretize the equations of motion.Using this approach,we performed numerical simulations to investigate the system’s global modes and assess the performance of the controller based on the GAM model.The results reveal that the GAM model can be used to directly calculate the exact global modes of SwLFAs and that the controller based on the discrete GAM model can achieve a control-index for a SwLFA in a shorter time with less input energy than other methods. 展开更多
关键词 FLEXIBLE SPACECRAFT GLOBAL ANALYTICAL mode dynamic modeling vibration control rigid-flexible coupling system
Breaking 12% efficiency in flexible organic solar cells by using a composite electrode
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作者 Guang Zeng Jingwen Zhang +3 位作者 Xiaobin Chen Hongwei Gu Yaowen Li Yongfang Li 《中国科学:化学英文版》 SCIE EI CAS CSCD 2019年第7期851-858,共8页
The performance of flexible organic solar cells(OSCs)significantly relies on the quality of transparent flexible electrode.Here,we used silver nanowires(AgNWs)with various weight ratios to dope high-conductive poly(3,... The performance of flexible organic solar cells(OSCs)significantly relies on the quality of transparent flexible electrode.Here,we used silver nanowires(AgNWs)with various weight ratios to dope high-conductive poly(3,4-ethylenedioxythiophene):polystyrene sulfonate(PH1000)to optimize the optical and electronic properties of PH1000 film.A high-quality flexible composite electrode PET/Ag-mesh/PH1000:AgNWs-20 with smooth surface,a low sheet resistance of 6Ω/sq and a high transmittance of 86%at 550-nm wavelength was obtained by doping 20 wt%AgNWs to PH1000(PH1000:AgNWs-20).The flexible OSCs based on the PET/Ag-mesh/PH1000:AgNWs-20 electrode delivered a power conversion efficiency(PCE)of12.07%with an open circuit voltage(Voc)of 0.826 V,a short-circuit current density(Jsc)of 20.90 m A/cm2and a fill factor(FF)of69.87%,which is the highest reported PCE for the flexible indium-tin oxide(ITO)-free OSCs.This work demonstrated that the flexible composite electrodes of PET/Ag-mesh/PH1000:AgNWs are promising alternatives for the conventional PET/ITO electrode,and open a new avenue for developing high-performance flexible transparent electrode for optoelectronic devices. 展开更多
关键词 FLEXIBLE ELECTRODES FLEXIBLE organic solar cells silver NANOWIRE composite ELECTRODE power conversion EFFICIENCY
Activated carbon felts with exfoliated graphene nanosheets for flexible all-solid-state supercapacitors
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作者 Zifang Zhao Xiaojun Wang +3 位作者 Minjie Yao Lili Liu Zhiqiang Niu Jun Chen 《中国化学快报:英文版》 SCIE CAS CSCD 2019年第4期915-918,共4页
The recent development of portable electronics promotes the growing demand for flexible energy storage devices. Supercapacitors are promising candidates due to their high power density. Therefore, flexible supercapaci... The recent development of portable electronics promotes the growing demand for flexible energy storage devices. Supercapacitors are promising candidates due to their high power density. Therefore, flexible supercapacitors are desired. Here, the porous activated carbon felts (ACFs) with exfoliated graphene nanosheets and rich oxygen-containing groups were fabricated by a facile thermal treatment strategy. Such ACFs can act as the flexible electrodes of all-solid-state supercapacitors directly without the use of binder and conductive materials. They exhibit excellent electrochemical properties, such as high specific areal capacitance, superior rate ability and long-term cycling stability. Moreover, the fabricated flexible all-solid-state supercapacitors based on ACFs deliver stable electrochemical performance under different bending states. 展开更多
关键词 Carbon felts GRAPHENE FLEXIBLE SUPERCAPACITORS Thermal treatment
Lending a Hand
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作者 Li Xiaoyang 《北京周报:英文版》 2019年第36期30-31,共2页
As the conventional September- October “golden” season of property sales approaches, the People’s Bank of China (PBC) has again bro u gh t the performance of the property market into the spotlight with its latest m... As the conventional September- October “golden” season of property sales approaches, the People’s Bank of China (PBC) has again bro u gh t the performance of the property market into the spotlight with its latest measure. In a statement on August 25, the central bank announced that China will link the personal mortgage loan rate to a new lending rate reference starting on October 8 to make the rate more flexible and market-driven. 展开更多
关键词 CONVENTIONAL GOLDEN FLEXIBLE
Displacement Response Reconstruction of Slender Flexible Structures Based on Cubic Spline Fitting Method 预览
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作者 HAN Qing-hua MA Ye-xuan +1 位作者 FENG Xin-xin XU Wan-hai 《中国海洋工程:英文版》 SCIE EI CSCD 2019年第2期226-236,共11页
How to reconstruct a dynamic displacement of slender flexible structures is the key technology to develop smart structures and structural health monitoring (SHM), which are beneficial for controlling the structural vi... How to reconstruct a dynamic displacement of slender flexible structures is the key technology to develop smart structures and structural health monitoring (SHM), which are beneficial for controlling the structural vibration and protecting the structural safety. In this paper, the displacement reconstruction method based on cubic spline fitting is put forward to reconstruct the dynamic displacement of slender flexible structures without the knowledge of modeshapes and applied loading. The obtained strains and displacements are compared with the results calculated by ABAQUS to check the method’s validity. It can be found that the proposed method can accurately identify the strains and displacement of slender flexible structures undergoing linear vibrations, nonlinear vibrations, and parametric vibrations. Under the concentrated force, the strains of slender flexible structures will change suddenly along the axial direction. With locally densified measurement points, the present reconstruction method still works well for the strain concentration problem. 展开更多
关键词 DISPLACEMENT RECONSTRUCTION CUBIC SPLINE FITTING slender flexible structures linear vibrations PARAMETRIC vibrations nonlinear vibrations
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基于柔性化的电子产品自动化测试系统设计 预览
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作者 李永利 《装备制造技术》 2019年第3期141-143,158共4页
随着电子技术的飞速发展,电子产品的自动化测试技术也得到快速发展。伴随着社会个性化需求的增加,为了满足电子产品的多配置、小批量的特性需求,本文在自动化测试的基础上,引入柔性测试方案,使电子产品的性能测试更加自动化、智能化。
关键词 电子产品 自动化测试 柔性
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A Modi ed Iterated Greedy Algorithm for Flexible Job Shop Scheduling Problem
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作者 Ghiath Al Aqel Xinyu Li Liang Gao 《中国机械工程学报:英文版》 SCIE EI CAS CSCD 2019年第2期157-167,共11页
The flexible job shop scheduling problem(FJSP) is considered as an important problem in the modern manufacturing system. It is known to be an NP-hard problem. Most of the algorithms used in solving FJSP problem are ca... The flexible job shop scheduling problem(FJSP) is considered as an important problem in the modern manufacturing system. It is known to be an NP-hard problem. Most of the algorithms used in solving FJSP problem are categorized as metaheuristic methods. Some of these methods normally consume more CPU time and some other methods are more complicated which make them di cult to code and not easy to reproduce. This paper proposes a modified iterated greedy(IG) algorithm to deal with FJSP problem in order to provide a simpler metaheuristic, which is easier to code and to reproduce than some other much more complex methods. This is done by separating the classical IG into two phases. Each phase is used to solve a sub-problem of the FJSP: sequencing and routing sub-problems. A set of dispatching rules are employed in the proposed algorithm for the sequencing and machine selection in the construction phase of the solution. To evaluate the performance of proposed algorithm, some experiments including some famous FJSP benchmarks have been conducted. By compared with other algorithms, the experimental results show that the presented algorithm is competitive and able to find global optimum for most instances. The simplicity of the proposed IG provides an e ective method that is also easy to apply and consumes less CPU time in solving the FJSP problem. 展开更多
关键词 ITERATED GREEDY Flexible JOB SHOP SCHEDULING problem DISPATCHING rules
有机和杂化阻变材料与器件 预览
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作者 陈威林 高双 +3 位作者 伊晓辉 尚杰 刘钢 李润伟 《功能高分子学报》 CAS CSCD 北大核心 2019年第4期434-447,共14页
阻变存储器具有功耗低、微缩性好、可大规模三维堆积、与互补金属氧化物半导体(CMOS)工艺兼容等诸多优势,可以满足高性能信息存储的关键要求。采用有机及杂化阻变材料作为存储介质构建器件,通过分子设计及合成策略不仅可实现器件的轻量... 阻变存储器具有功耗低、微缩性好、可大规模三维堆积、与互补金属氧化物半导体(CMOS)工艺兼容等诸多优势,可以满足高性能信息存储的关键要求。采用有机及杂化阻变材料作为存储介质构建器件,通过分子设计及合成策略不仅可实现器件的轻量化和柔性集成,还可以灵活地调控分子的电学特征以及器件的存储性能。本文全面综述了有机及杂化阻变材料与器件的最新进展,特别关注它们在电学性能调控和柔性存储性能方面的设计原则,并对有机及杂化阻变材料与柔性存储器件的当前挑战及未来发展前景进行了讨论。 展开更多
关键词 有机材料 有机-无机杂化材料 阻变 非易失性存储器 柔性
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Flexible and reusable cap-like thin Fe2O3 film for SERS applications
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作者 Jiangtao Xu Xiaoting Li +3 位作者 Yuxiang Wang Ronghui Guo Songmin Shang Shouxiang Jiang 《纳米研究:英文版》 SCIE EI CAS CSCD 2019年第2期381-388,共8页
Cap-like α-Fe2O3 films are fabricated and deposited onto quartz fabric by using radio frequency magnetron sputtering and annealing.The treated fabric sample in this study shows highly sensitive surface-enhanced Raman... Cap-like α-Fe2O3 films are fabricated and deposited onto quartz fabric by using radio frequency magnetron sputtering and annealing.The treated fabric sample in this study shows highly sensitive surface-enhanced Raman scattering (SERS) and excellent flexibility,reproducibility and stability.In addition,the sample can be recovered after a washing process with an organic solvent and repeatedly used.The sensitive SERS performance is attributed to chemical enhancement through a charge transfer process.Moreover,the SERS performance is also found to be dependent on the light coupling effect.When the light absorbance rate of the α-Fe2O3 films increases at a wavelength near that of laser light,the film shows excellent sensitivity due to light coupling effect. 展开更多
关键词 Α-FE2O3 QUARTZ fabric FLEXIBLE surface-enhanced RAMAN scattering (SERS) RAMAN sensor
基于黑磷烯/氧化石墨烯双介质层的柔性电容式压力传感器 预览
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作者 聂萌 郭安琪 +1 位作者 陈佳琦 徐峰 《传感技术学报》 CAS CSCD 北大核心 2019年第4期481-484,共4页
设计并制备了由黑磷烯/氧化石墨烯双层材料为介质层的电容式柔性压力传感器,该传感器结构以ITO为电容上下极板,PET为柔性基底,并对该传感器进行了系统的性能测试与分析。着重研究了该传感器在不同压力量程内的灵敏度,进而分析了其温度... 设计并制备了由黑磷烯/氧化石墨烯双层材料为介质层的电容式柔性压力传感器,该传感器结构以ITO为电容上下极板,PET为柔性基底,并对该传感器进行了系统的性能测试与分析。着重研究了该传感器在不同压力量程内的灵敏度,进而分析了其温度漂移特性。测试结果表明,以黑磷烯/氧化石墨烯薄膜为双介质层的电容式柔性压力传感器在0~3.12 kPa压力量程内灵敏度可达到1.60 kPa -1 。同时,对该传感器和以氧化石墨烯薄膜为单介质层的传感器进行了弯曲应变性能的对照实验,可知具有双介质层的传感器结构能够显著提高传感器的输出特性。 展开更多
关键词 柔性 电容式压力传感器 黑磷烯 氧化石墨烯 灵敏度
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碳纤维支撑柔性碳硫复合电极的制备、物性及电池性能研究 预览
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作者 李亚东 李伟平 +2 位作者 王琴 郑道光 王建新 《无机材料学报》 SCIE EI CAS CSCD 北大核心 2019年第4期373-378,共6页
锂硫电池作为极具潜力的下一代二次电池受到广泛关注。然而,对于含硫正极的研究仍处于实验探索阶段,商业化的碳纤维毡应用于硫正极鲜有报道。本研究制备了锂硫电池用碳纤维支撑柔性碳硫复合电极,并对其进行了物性及电池性能的研究。结... 锂硫电池作为极具潜力的下一代二次电池受到广泛关注。然而,对于含硫正极的研究仍处于实验探索阶段,商业化的碳纤维毡应用于硫正极鲜有报道。本研究制备了锂硫电池用碳纤维支撑柔性碳硫复合电极,并对其进行了物性及电池性能的研究。结果发现,碳纤维毡具有多孔隙的三维网络结构,与具有微孔结构的多孔碳共同构成正极支撑体,能够物理固定正极材料,有助于提高电池的能量密度和锂硫正极的导电性,界面电阻由原来的97.9Ω降到22.6Ω。进一步研究表明,碳纤维毡做集流体的样品在首圈0.05C倍率下,具有996.7mAh/g的放电比容量,在2C高倍率下循环140圈后仍保持666.7mAh/g的放电比容量,而铝箔样品仅为772.9和471.6mAh/g。同时,本研究使用的LA132水系粘结剂、super-P导电剂价格低廉,球磨制备工艺可规模化生产、安全环保,可以为锂硫电池工业化生产和应用提供参考。 展开更多
关键词 锂硫电池 碳纤维支撑 柔性 传统铝箔
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超浅水浮式波浪能发电装置弹性系泊系统及水动力性能的数值与模型试验研究
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作者 黄硕 盛松伟 +2 位作者 游亚戈 张运秋 王振鹏 《太阳能学报》 EI CAS CSCD 北大核心 2019年第3期715-723,共9页
超浅水环境下浮式波浪能发电装置系泊系统性能的优劣直接影响装置在极限海况下的生存性和工作海况下的波浪能俘获性。针对波能装置运动特点和岛屿周边海域经济性开发的需要,设计一套适合超浅水环境的自动对浪型多点弹性系泊系统,并在系... 超浅水环境下浮式波浪能发电装置系泊系统性能的优劣直接影响装置在极限海况下的生存性和工作海况下的波浪能俘获性。针对波能装置运动特点和岛屿周边海域经济性开发的需要,设计一套适合超浅水环境的自动对浪型多点弹性系泊系统,并在系泊线中加入非线弹性拉伸材料--高弹性索。首先以鹰式波浪能装置为系泊对象,给出混合高弹性索和聚酯纤维系泊系统2种设计方案,通过对比分析,发现高弹性索可有效降低锚泊线的最大张力和普通锚链的用量,减轻系泊系统重量。混合高弹性索系泊系统用于超浅水环境下的浮式波浪能装置更具优越性。在此基础上,对极限工况下混合高弹性索系泊鹰式和细长体波浪能装置水动力性能进行时域耦合和水池模型试验研究。研究表明混合高弹性索多点弹性系泊系统能满足一般浮式波浪能装置在浅水大漂移载荷等恶劣海况下对锚泊系统的要求。 展开更多
关键词 波浪能装置 系泊系统 弹性 浅水 水动力
Debris flow impact on flexible barrier:effects of debrisbarrier stiffness and flow aspect ratio
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作者 SONG Dong-ri ZHOU Gordon G.D +1 位作者 CHOI Clarence Edward ZHENG Yun 《山地科学学报:英文版》 SCIE CSCD 2019年第7期1629-1645,共17页
Conventionally,flexible barriers are rated based on their ability to resist a free-falling boulder with a particular input energy.However,there is still no well-accepted approach for evaluating performance of flexible... Conventionally,flexible barriers are rated based on their ability to resist a free-falling boulder with a particular input energy.However,there is still no well-accepted approach for evaluating performance of flexible barrier under debris flow impact.In this study,a large-nonlinear finite-element model was used to back-analyze centrifuge tests to discern the effects of impact material type,barrier stiffness,and flow aspect ratio(flow height to flow length)on the reaction force between the impacting medium and flexible barrier.Results show that,in contrast to flexible barriers for resisting rockfall,the normal impact force induced by the highly frictional and viscous debris is insensitive to barrier stiffness.This is because the elongated distributions of kinetic energy are mainly dissipated by the internal and boundary shearing,and only a small portion is forwarded to the barrier.Furthermore,a new stiffness number is proposed to characterize the equivalent stiffness between a debris flow or a boulder,and a flexible barrier.Under the circumstance of an extremely elongated debris flow event,i.e.,low aspect ratio,the load on a barrier is dominated by the static component and thus not sensitive to the barrier stiffness. 展开更多
关键词 Debris FLOW FLEXIBLE BARRIER IMPACT STIFFNESS FLOW aspect ratio
Comparison Between Different Finite Element Analyses of Unbonded Flexible Pipe via Different Modeling Patterns
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作者 庞国良 陈超核 +1 位作者 沈义俊 刘夫永 《上海交通大学学报:英文版》 EI 2019年第3期357-363,共7页
Three kinds of models based on the same flexible pipe with 8 layers have been separately created to investigate the effects of different modeling approaches on numerical simulation results of finite element(FE)models ... Three kinds of models based on the same flexible pipe with 8 layers have been separately created to investigate the effects of different modeling approaches on numerical simulation results of finite element(FE)models for unbonded flexible pipes.Then the mechanical property of the unbonded flexible pipe under tension,torsion and bending load has been analyzed and compared via ABAQUS software on the basis of three created models.The research shows that different modeling methods of flexible pipes make a great difference in the results.Especially,modeling simplifications of the carcass and pressure armor have a great impact on the accuracy of the results.Model 3,in which the carcass is simulated by spiral isot ropic shell and other layers are Simula ted by solid element,possesses good adaptability,which has been proved by comparing the experiment data and other models.This paper can offer a reference for the FE modeling methods,selection and mechanical property analysis of unbonded flexible pipe. 展开更多
关键词 UNBONDED flexible pipe NUMERICAL simulation methods FINITE element(FE)analysis
Effects of Flexibility and Suspension Configuration of Main Shaft on Dynamic Characteristics of Wind Turbine Drivetrain
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作者 Jianjun Tan Caichao Zhu +2 位作者 Chaosheng Song Huali Han Yao Li 《中国机械工程学报:英文版》 SCIE EI CAS CSCD 2019年第2期224-238,共15页
The current research of wind turbine drivetrain is mainly concentrated in dynamic characteristics of gearbox with a specific suspension of main shaft, such as one-point and two-point suspension. However, little attent... The current research of wind turbine drivetrain is mainly concentrated in dynamic characteristics of gearbox with a specific suspension of main shaft, such as one-point and two-point suspension. However, little attention is paid to the e ects of these suspension configurations on the dynamic responses of wind turbine gearbox. This paper investigates the influences of suspension configurations of main shaft on the dynamic characteristics of drivetrain. For evaluating the dynamic behaviors of drivetrain with multi-stage transmission system more realistically, a dynamic modeling approach of drivetrain is proposed based on Timoshenko beam theory and Lagrange’s equation. Considering the flexibility and di erent suspension configurations of main shaft, time-varying mesh sti ness excitation, time-varying transmission error excitation and gravity excitation, etc., a three-dimensional dynamic model of drivetrain is developed, and the dynamic responses of drivetrain are investigated. Results show that with the one-point suspension of main shaft, the resonance frequencies in gearbox, especially at the low-speed stage, obviously shift to the higher frequency range compared to the gearbox without main shaft, but this trend could be inversed by increasing main shaft length. Meanwhile, the loads in main shaft, main shaft bearing and carrier bearing are greatly sensitive to the main shaft length. Hence, the load sharing is further disrupted by main shaft, but this e ect could be alleviated by larger load torque. Comparing to the one-point suspension of main shaft, there occurs the obvious load reduction at the low-speed stage with two-point suspension of main shaft. However, those advantages greatly depend on the distance between two main bearings, and come at the expense of increased load in upwind main shaft unit and the corresponding main bearing. Finally, a wind field test is conducted to verify the proposed drivetrain model. This study develops a numerical model of drivetrain which is able to evaluate the e ects of di ere 展开更多
关键词 WIND TURBINE drivetrain Flexible shafts SUSPENSION CONFIGURATION Dynamic RESPONSES Experimental study
Optimization of Ethylene Glycol Doped PEDOT:PSS Transparent Electrodes for Flexible Organic Solar Cells by Drop-coating Method
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作者 Hui-Qin Cui Rui-Xiang Peng +4 位作者 Wei Song Jian-Feng Zhang Jia-Ming Huang Li-Qiang Zhu Zi-Yi Ge 《高分子科学:英文版》 SCIE CAS CSCD 2019年第8期760-766,共7页
Fabrication of flexible transparent electrodes(FTEs) is one of the core technologies in the field of flexible electronics. Among multiple choices of FTEs, poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonic acid)(P... Fabrication of flexible transparent electrodes(FTEs) is one of the core technologies in the field of flexible electronics. Among multiple choices of FTEs, poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonic acid)(PEDOT:PSS) has shown its promising application in roll-to-roll manufacturing. A simple yet effective method for substantially boosting the conductivity of these conducting polymer films without causing large-domain aggregations is by adding ethylene glycol(EG) as dopant. Herein, we investigated in detail the effects of the secondary solvent of ethylene glycol(EG) on the optical and electrical characteristics of PEDOT:PSS films. The modified PEDOT:PSS FTEs were deposited using drop-coating techniques as it had greater compatibility for large-area samples than the conventional spin-coating method did. The 6% EG-doped PEDOT:PSS FTE via drop-coating method achieved a high figure of merit(FoM) value of 47.24 and the devices fabricated using the optimal PEDOT:PSS FTE yielded a high power conversion efficiency(PCE) of 8.89%, mostly attributed to the modified PEDOT:PSS films that had excellent optical and electrical characteristics with low surface roughness. These results suggested that EG-doping could effectively boost the conductivity of PEDOT:PSS films and that the modified PEDOT:PSS FTE is suitable for roll-to-roll manufacturing in the future. 展开更多
关键词 PEDOT:PSS DOPING CONDUCTIVITY FLEXIBLE TRANSPARENT electrodes Organic solar cells
Control Algorithm Using a Revised MIP Method to Deal with Livelocks in S~4R of Petri Nets
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作者 李绍勇 吴宗礼 +3 位作者 李海林 魏先宏 蔡颖 厚彩琴 《上海交通大学学报:英文版》 EI 2019年第2期190-195,共6页
Livelocks, like deadlocks, can result in serious results in running process of flexible manufacturing systems(FMSs). Current deadlock control policies(DCPs) based on mixed integer programming(MIP) cannot detect siphon... Livelocks, like deadlocks, can result in serious results in running process of flexible manufacturing systems(FMSs). Current deadlock control policies(DCPs) based on mixed integer programming(MIP) cannot detect siphons that cause and cope with livelocks in Petri nets. This study proposes a revised mixed integer programming(RMIP) method to directly solve the new smart siphons(NSSs) associated with livelocks in a system of sequential systems with shared resources(S~4 R), a typical subclass of generalized Petri net models. Accordingly,the solved NSSs are max’-controlled by adding the corresponding control places(CPs). As a result, an original S~4 R system with livelocks can be converted into the live controlled Petri net system. The related theoretical analysis and an example are given to demonstrate the proposed RMIP and the corresponding control algorithm(CA). 展开更多
关键词 flexible manufacturing system(FMS) PETRI NETS revised mixed INTEGER programing(RMIP) livelocks live controlled PETRI net SYSTEM
Effect of vertical stress rest period on deformation behaviour of unbound granular materials:Experimental and numerical investigations 预览
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作者 Ali Alnedawi Kali Prasad Nepal +1 位作者 Riyadh Al-Ameri Mohanad Alabdullah 《岩石力学与岩土工程学报:英文版》 CSCD 2019年第1期172-180,共9页
Repeated load triaxial test is used to assess the deformation behaviour of unbound granular materials(UGMs)in flexible road pavements.Repeated load pulse characteristics(i.e.shape,loading period and rest period)are th... Repeated load triaxial test is used to assess the deformation behaviour of unbound granular materials(UGMs)in flexible road pavements.Repeated load pulse characteristics(i.e.shape,loading period and rest period)are the stress configurations used in the experimental set-up to simulate the passing axle loads.Some researchers and standard testing protocols suggest a rest period of varying durations after a loading phase.A thorough review of existing literature and practises has revealed that there is no agreement about the effect of the rest period of vertical stress pulse on the deformation behaviour of the UGMs.Therefore,the main objective of this study is to investigate the effect of repeated stress rest period on the deformation behaviour of UGMs experimentally.Experiments are conducted,both with and without rest period,using basalt and granite crushed rocks from Victoria,Australia.Furthermore,in order to gain insight into the effect of the rest period,finite element modelling is also developed.Both the experimental and modelling results show that the rest period has a noticeable effect on both resilient and permanent deformation behaviours of UGMs.It is,therefore,recommended to take extra precautions while adopting a particular standard testing protocol and to supplement the results by additional tests with different loading configurations. 展开更多
关键词 Flexible PAVEMENT Unbound GRANULAR materials(UGMs) Repeated load TRIAXIAL test Resilient MODULUS PERMANENT deformation Finite element modelling
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浅析建筑刚性防水材料与柔性防水材料检测 预览
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作者 林双庆 《江西建材》 2019年第9期32-32,34共2页
文章主要对建筑刚性防水材料与柔性防水材料的检测展开论述,以推动相关行业不断发展进步。
关键词 建筑防水 材料 柔性 刚性 检测
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柔性自动贴膜设备的开发及应用 预览
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作者 陈国强 高明 《机电工程技术》 2019年第1期27-28,118共3页
针对目前家电行业存在的,防止注塑件表面刮伤,需人工在其表面贴保护膜的现状,进行了全自动控制注塑件贴保护膜技术的系统开发及应用。该技术的应用解决了传统人工贴保护膜劳动强度大且耗费人力的弊端。实现了产品从注塑机注塑成型后无... 针对目前家电行业存在的,防止注塑件表面刮伤,需人工在其表面贴保护膜的现状,进行了全自动控制注塑件贴保护膜技术的系统开发及应用。该技术的应用解决了传统人工贴保护膜劳动强度大且耗费人力的弊端。实现了产品从注塑机注塑成型后无需人工中间操作即可自动完成贴保护膜的目的。同时,该技术的应用也为家电行业针对复杂注塑件的外饰面贴保护膜的方法提供了较为有效的参考价值,将有效替代高重复性的人工作业。 展开更多
关键词 自动 贴保护膜 柔性
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