踏板式自行车的结构强度、刚度的计算与分析

本文对国内、外两种踏板式自行车的结构强度,刚度进行了计算与分析,结论是沈阳自行车研究所设计的踏板式自行车比国外的踏板式自行车更安全,更舒适。此项研究对改进自行车的车型和结构设计有参考价值。     

The influence of speed,cyclists’ age,pedaling frequency,and observer age on observers’ time to arrival judgments of approaching bicycles and e-bikes

Given their potential to reach higher speed levels than conventional bicycles, the growing market share of e-bikes has been the reason for increased concerns regarding road safety. Previous studies have shown a clear relationship between object approach speed and an observers’ judgment of when the object would reach a predefined position (i.e., time to arrival, TTA), with higher speed resulting in longer TTA estimates. Since TTA estimates have been linked to road users’ decisions of whether or not to cross or turn in front of approaching vehicles, the higher potential speeds of e-bikes might result in an increased risk for traffic conflicts. The goal of the two experiments presented in this paper was to examine the influence of speed and a variety of other factors on TTA estimation for conventional bicycles and for e-bikes. In both experiments, participants from two age groups (20–45 years old and 65 years or older) watched video sequences of bicycles approaching at different speeds (15–25 km/h) and were asked to judge the TTA at the moment the video was stopped. The results of both experiments showed that an increase in bicycle approach speed resulted in longer TTA estimates (measured as the proportion of estimated TTA relative to actual TTA) for both bicycle types (η_p²_Exp.1 = .489, η_p²_Exp.2 = .705). Compared to younger observers, older observers provided shorter estimates throughout (Exp. I: M_Diff = 0.35, CI [0.197, 0.509], η_p² = .332, Exp. II: M_Diff = 0.50, CI [.317, 0.682], η_p² = .420). In Experiment I, TTA estimates for the conventional bicycle were significantly shorter than for the e-bike (M_Diff = 0.03, CI [.007, 0.044], η_p² = .154), as were the estimates for the elder cyclist compared to the younger one (M_Diff = 0.05, CI [.025, 0.066], η_p² = .323). We hypothesized that the cause for this effect might lie in the seemingly reduced pedaling effort for the e-bike as a result of the motor assistance it provides. Experiment II was able to show that a high pedaling frequency indeed resulted in shorter TTA estimates compared to a low one (M_Diff = 0.07, CI [0.044, 0.092], η_p² = .438). Our findings suggest that both the e-bikes’ potential to reach higher speeds and the fact that they reduce the perceived cycling effort increase the risk of TTA misjudgments by other road users.     

城市低碳交通发展策略研究--以深圳市为例

通过解析城市低碳交通的内涵,提出了低碳交通发展的主要路径,以深圳市为例,其发展低碳交通时应该采取“空间减碳、方式减碳、技术减碳、管理减碳”四位一体的综合战略。     

电动自行车用VRLA电池循环特性的研究

分别研究了电动车用VRLA电池组在85%DoD和全放电循环模式下的平均电压、不均衡率和电池容量的变化规律。试验结果表明:蓄电池长期85%DoD循环,会产生电池容量衰减问题,多次全放电可有效恢复。含添加剂M的蓄电池,容量衰减和不均衡率等指标得到明显改善。蓄电池最终失效是由失水引起的。因此,采用合适的循环模式,可以减少失水,有效地延长使用寿命。     

Advancing Multicomponent Strategies to Macrobicyclic Peptides

Macrocyclization of peptides is typically used to fix specific bioactive conformations and improve their pharmacological properties. Recently, macrobicyclic peptides have received special attention owing to their capacity to mimic protein structures or be key components of peptide-drug conjugates. Here, we describe the development of novel synthetic strategies for two distinctive types of peptide macrobicycles. A multicomponent macrocyclo-dimerization approach is introduced for the production of interconnected β-turns, allowing two macrocyclic rings to be formed and dimerized in one pot. Also, an on-resin double stapling strategy is described for the assembly of lactam-bridged macrobicycles with stable tertiary folds.