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991.
针对直线倒立摆的控制问题,利用拉格朗日方法对实际物理模型进行线性化处理建立数学模型,为了提高控制精度,将不确定外扰和未建模动态视为一个综合扰动项,运用扩张状态观测器对系统状态和综合扰动项进行观测,设计了基于扩张状态观测器的直线倒立摆状态反馈稳摆控制器;用能量反馈方法和bang-bang控制器实现倒立摆起摆到稳摆的切换。通过无干扰和有干扰状态直线倒立摆起摆到稳摆过程的实验研究,表明系统能够有效的抑制外界干扰,具有较强的鲁棒性。 相似文献
992.
ABSTRACTStudy on dynamic tensile properties and atomic chain fabrication of single nanowire, for understanding its dynamic tensile properties and unique physical properties of atomic chain to fabricate atom scale devices, is one of frontier research issues in nano-scale science. However, how to assemble single nanowire on a tensible micro-structure becomes one of the most difficult problems, which severely restricts the development of this research field. In this paper, after the ultrahigh tensible microelectrode chip is fabricated by micro-electromechanical systems technology, hexamethyldisilazane is utilized to improve hydrophobicity of the chip, and then a micro-droplet dielectrophoresis experimental platform and technology is developed to assemble single nanowire on the sensible microelectrode. Experimental results show that accurate and efficient assembly of single Cu nanowire is realized, which contributes greatly to the further research of dynamic tensile properties and atomic chain fabrication. And for guiding the assembly experiments, finite element technology is also utilized to analyze the local micro electro-field around the microelctrodes during dieletrophoresis experiments. 相似文献
993.
双弹簧是燃料组件定位格架的重要零件,根据双弹簧成形工艺和毛坯尺寸的分析计算,确定了两种工艺和排样设计,同时设计了一付双弹簧斜楔滑块打弯成形进模,经试冲表明,采用新的成形级进模生产的产品,其各项成形指标均达到技术要求。 相似文献
994.
995.
针对飞机工装橡胶压模设计步骤繁琐,效率低下等问题,在深入分析橡胶压模结构和归纳总结橡胶压模类型的基础上,总结已有的设计流程,并在三维CAD 平台CATIA 上,利用CAA 开发工具实现橡胶压模快速设计系统,实现了模具体的快速生成,模芯的快速装配。并应用于某大型航空企业的工装设计中,取得了良好的效果。 相似文献
996.
以某综合体育馆钢桁架施工为例,针对该工程施工现场作业场地有限,无法进行桁架的整体吊装的情况,采用打断分片吊装在空中焊接后实现整体拼装的方法,并介绍了该钢桁架施工技术的具体工艺流程及其操作要点,对钢桁架技术的发展和创新具有积极的促进作用。 相似文献
997.
Dual-arm robots provide efficient approach for automated execution of complex assembly operations. With bimanual-manipulation, a dual-arm robot can simultaneously control relative motion and interaction of assembly counterparts in a dexterous human-like manner. This requires, however, sophisticated programming and control algorithms for arms cooperation. This paper addresses the development of an advanced industrial dual-arm robot system with novel capabilities, such as easy and rapid commissioning, compliance control of bimanual interaction in all assembly process phases, as well as intuitive planning and programming. The robot can be leased and easily integrated in assembly environment sharing the same workspace with human workers. 相似文献
998.
Cheviri Ghanashyam;Rajeev K. Sinha;Aseefhali Bankapur; 《Small Methods》2024,8(1):2301086
A transportable reversible assembly of gold nanoparticles (AuNPs) in an aqueous environment addresses the need for in situ surafce-enhanced Raman spectroscopy (SERS) hotspot creation for biological applications. Usually, light-directed AuNP assembly methods use higher laser powers and surfactants and are, hence, unsuitable for biological applications. Here, surface plasmon polaritons-assisted dynamic assembly of AuNPs are demonstrated at laser power density as low as 100 nW µm−2. The AuNP assembly with multiple controllable hotspots is generated in an Au–water interface for solution-based SERS measurements. The major advantage of the method is that the interparticle nanogap is tunable to achieve analyte and AuNP-specific optimum SERS enhancement. The SERS intensity is reproducible on multiple reassembly cycles and assembly attempts, proving repeatability in the produced nanogap pattern. The assembly experiments reveal the influence of AuNP surface charge and the resulting polarizability on the SPP forces. The developed system and method can detect sulforhodamine 101 (SR101) dye molecules at concentrations as low as 10−10 m. Further, the SERS measurements on double-stranded DNA suggest that the molecules are oriented in a fashion to expose adenosine to the enhanced field, leading to its dominance in the recorded spectra. 相似文献
999.
Meihe Yuan Yuhang Dong Zhaoyue Lv Jinqiao Liu Mingxing Liu Mengdi Xu Xiaocui Guo Chi Yao Dayong Yang 《Advanced functional materials》2024,34(17):2312880
Developing artificial material systems to rationally interfere with organelles is emerging as a promising route to regulate the behaviors and fate of cells, thus providing new therapeutic strategies. Herein, a DNA nanoparticles (DNPs)-based material system is reported, which achieves controlled sequential assembly inside cells, and realizes specific interference toward mitochondria. Two types of DNPs are synthesized via radical polymerization, followed with cascade hybridization chain reaction of hairpin DNA with Cyanine5 (Cy5) for mitochondrial targeting, and with complementary sequences for base pairing, respectively. DNPs with Cy5 (Cy5-DNPs) first entered cells to target mitochondria, and the other DNPs with complementary sequences entered cells after an interval to sequentially assemble with Cy5-DNPs into aggregates via base pairing. Mitochondrial interference is achieved, including increased reactive oxygen species, decreased membrane potential, abnormal elevation of Ca2+ level, decreased adenosine triphosphate, and attenuated cellular migration rate. In particular, by regulating the intervals of two types of DNPs entering cells, the mitochondrial interference degree is controllably modulated. This work achieves regulated organelles interference via the precise controlled self-assembly of DNA nanostructures inside cells, which is envisioned to have great potential in precision biomedicine. 相似文献
1000.
Huayang Wang Haowen Qian Wen Li Ke Wang Hao Li Xihuang Zheng Pan Gu Senbin Chen Mingdong Yi Jiangping Xu Jintao Zhu 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(23):2208288
In this work, it is reported that large-area (centimeter-scale) arrays of non-close-packed polystyrene-tethered gold nanorod (AuNR@PS) can be prepared through a liquid–liquid interfacial assembly method. Most importantly, the orientation of AuNRs in the arrays can be controlled by changing the intensity and direction of electric field applied in the solvent annealing process. The interparticle distance of AuNR can be tuned by varying the length of polymer ligands. Moreover, the AuNR@PS with short PS ligand are favorited to form orientated arrays with the assistance of electric field, while long PS ligands make the orientation of AuNRs difficult. The orientated AuNR@PS arrays are employed as the nano-floating gate of field-effect transistor memory device. Tunable charge trapping and retention characteristics in the device can be realized by electrical pulse with visible light illumination. The memory device with orientated AuNR@PS array required less illumination time (1 s) at the same onset voltage in programming operation, compared to the control device with disordered AuNR@PS array (illumination time: 3 s). Moreover, the orientated AuNR@PS array-based memory device can maintain the stored data for more than 9000 s, and exhibits stable endurance characteristic without significant degradation in 50 programming/reading/erasing/reading cycles. 相似文献