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排序方式: 共有5373条查询结果,搜索用时 15 毫秒
51.
基于神经网络的钞票真假识别研究 总被引:3,自引:1,他引:2
利用神经网络与光电检测的技术研制了钞票真假识别系统.介绍了系统的结构组成、工作原理、软件系统、神经网络的优化设计、实验及测试结果.经实践验证,其识别结果稳定可靠,可应用于金融智能防伪点钞机与ATM机中. 相似文献
52.
Miriam R. B. Porzberg Laust Moesgaard Catrine Johansson Udo Oppermann Jacob Kongsted Jasmin Mecinovi 《Molecules (Basel, Switzerland)》2022,27(3)
Epigenetic readout of the combinatorial posttranslational modification comprised of trimethyllysine and asymmetric dimethylarginine (H3K4me3R8me2a) takes place via biomolecular recognition of tandem Tudor-domain-containing protein Spindlin1. Through comparative thermodynamic data and molecular dynamics simulations, we sought to explore the binding scope of asymmetric dimethylarginine mimics by Spindlin1. Herein, we provide evidence that the biomolecular recognition of H3K4me2R8me2a is not significantly affected when R8me2a is replaced by dimethylarginine analogues, implying that the binding of K4me3 provides the major binding contribution. High-energy water molecules inside both aromatic cages of the ligand binding sites contribute to the reader–histone association upon displacement by histone peptide, with the K4me3 hydration site being lower in free energy due to a flip of Trp151. 相似文献
53.
Xing Zhang Shao-Yuan Su Xuan-Ting Chen Ling-Yi Shen Qi-Long Zhang Xin-Long Ni Hong Xu Zhi-Yong Wang Carl Redshaw 《Molecules (Basel, Switzerland)》2022,27(8)
In comparison with the numerous studies that have centered on developing molecular frameworks for the functionalization of fluorescent materials, less research has addressed the influence of the side chains, despite such appendages contributing significantly to the properties and applications of fluorescent materials. In this work, a new series of cationic fluorescent probes with AIE characteristics have been developed, which exhibit unique sensitivity for charge-diffusion anions, namely HSO3−, via the interactions of ions and the cooperation of the controllable hydrophobicity. The impact of the alkyl chain length attached at the cationic probes suggested that the fluorescent intensity and sensitivity of the probes could be partially enhanced by adjusting their aggregation tendency through the action of the hydrophobic effect under aqueous conditions. DLS and SEM images indicated that different particle sizes and new morphologies of the probes were formed in the anion-recognition-triggered self-assembly process, which could be attributed to the composite effect of electrostatic actions, Van der Waals forces and π-π stacking. 相似文献
54.
A new protein molecularly imprinted polymer (MIP) was prepared with grafting polyvinyl alcohol as assistant recognition polymer chains (ARPCs). The ARPCs and acrylamide monomers were interpenetrated and then polymerized on the surface of macroporous acrylate adsorbent spheres. The template BSA was removed by treatment with 2.00 mol L-1 potassium chloride (KCl) solution and the adsorbed proteins were detected with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). 0.150, 0.500, and 2.00 mo... 相似文献
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Novel acetylenes carrying urea groups, 1-(4-ethynylphenyl)-3-(4-nitrophenyl) urea (1), 1-(4-propargyl)-3-(4-nitrophenyl) urea (2), were synthesized and polymerized with rhodium catalyst. Polymers [poly(1) and poly(2)] with moderate molecular weights were obtained in good yields. The anion sensing ability of poly(1) and poly(2) was estimated using the tetra-n-butylammonium (TBA) salts of a series of anions in DMF. Upon the addition of F-, the color of the DMF solution of poly(1) and poly(2) immediately turned to a different color, while the color of solution changed slightly upon addition of Cl-, HSO4-, Br-, and NO3-, indicating the F- sensing ability of poly(1) and poly(2). The 1H-NMR titrations of poly(1) revealed that the colorimetric response of poly(1) was triggered by the urea/F- interaction through the hydrogen bonding and/or deprotonation process. The absorption spectra titration and Hill plot analysis were carried out to measure the F- binding ability, and the Hill coefficient in the poly(1)/F- complexation was found to be 5.8. This result clearly indicated that this binding mode between poly(1) and F- was based on a positive homotropic allosterism. 相似文献
57.
Giacomo Picci Matthew T. Mulvee Claudia Caltagirone Vito Lippolis Antonio Frontera Rosa M. Gomila Jonathan W. Steed 《Molecules (Basel, Switzerland)》2022,27(4)
Three novel bis-urea fluorescent low-molecular-weight gelators (LMWGs) based on the tetraethyl diphenylmethane spacer—namely, L1, L2, and L3, bearing indole, dansyl, and quinoline units as fluorogenic fragments, respectively, are able to form gel in different solvents. L2 and L3 gel in apolar solvents such as chlorobenzene and nitrobenzene. Gelator L1 is able to gel in the polar solvent mixture DMSO/H2O (H2O 15% v/v). This allowed the study of gel formation in the presence of anions as a third component. An interesting anion-dependent gel formation was observed with fluoride and benzoate inhibiting the gelation process and H2PO4−, thus causing a delay of 24 h in the gel formation. The interaction of L1 with the anions in solution was clarified by 1H-NMR titrations and the differences in the cooperativity of the two types of NH H-bond donor groups (one indole NH and two urea NHs) on L1 when binding BzO− or H2PO4− were taken into account to explain the inhibition of the gelation in the presence of BzO−. DFT calculations corroborate this hypothesis and, more importantly, demonstrate considering a trimeric model of the L1 gel that BzO− favours its disruption into monomers inhibiting the gel formation. 相似文献
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59.
针对货车运行故障动态图像检测,提出无故障目标识别工作模式,解决货车枕簧丢失故障的自动识别问题。利用Haar特征提取枕簧特征信息,基于AdaBoost算法选取特征并构建层叠分类器,等比缩放搜索窗口检测货车图像,最终分选出无故障的枕簧图像,从而大大地减少了待识别图像的数量,显著地提高了人工识别效率。实验表明,该算法使用的特征简单,搜索策略高效,不受枕簧位置、缩放和旋转的影响,抗噪能力强,对分辨率低、局部遮挡、光照不足或过度曝光等质量较差的图像仍具有很强的适应性,所提出的方案能够满足全天候条件下的货车枕簧目标识别,为货车故障动态图像检测的工程化应用奠定了基础。 相似文献
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