基于实例的产品快速设计技术

以齿轮传动机构设计为例,从零件造型、装配、更改方案快速设计,直到最终得到零件图,说明现代机械设计方法 和手段的具体实现。     

Ultrafast Zn2+ Intercalation and Deintercalation in Vanadium Dioxide

Although rechargeable aqueous zinc‐ion batteries have attracted extensive interest due to their environmental friendliness and low cost, they still lack suitable cathodes with high rate capabilities, which are hampered by the intense charge repulsion of bivalent Zn²⁺. Here, a novel intercalation pseudocapacitance behavior and ultrafast kinetics of Zn²⁺ into the unique tunnels of VO₂ (B) nanofibers in aqueous electrolyte are demonstrated via in situ X‐ray diffraction and various electrochemical measurements. Because VO₂ (B) nanofibers possess unique tunnel transport pathways with big sizes (0.82 and 0.5 nm² along the b‐ and c‐axes) and little structural change on Zn²⁺ intercalation, the limitation from solid‐state diffusion in the vanadium dioxide electrode is eliminated. Thus, VO₂ (B) nanofibers exhibit a high reversible capacity of 357 mAh g^?1, excellent rate capability (171 mAh g^?1 at 300 C), and high energy and power densities as applied for zinc‐ion storage.     

Surface-functionalized pomelo peel-derived biochar with mercapto-1,2,4-triazloe for selective elimination of toxic Pb (II) in aqueous solutions

A novel biochar adsorbent (GP-AMT) is prepared by functionalizing biochar derived from pomelo peel to eliminate Pb (II) from water. GP-AMT was characterized by FTIR, SEM, BET, TGA and XPS. GP-AMT has a large specific area and is multiaperture. The adsorption performance was studied. At the pH = 5, the maximum uptake amount of Pb(II) on GP-AMT reached 420 mg/g. The sorption behavior of GP-AMT obeys with Langmuir and pseudo second-order formula, which shows that the adsorbing property of GP-AMT is uniform chemical sorption. Thermodynamic studies attested that the sorption was an irreversible endothermic course. GP-AMT demonstrated excellent selectivity and reproducibility. After 5 cycles, it still has an excellent sorption property. XPS and zeta potential analysis revealed that the adsorbing nature of GP-AMT for heavy metal ions was coordination and ion exchange. In conclusion, surface modification of biochar can significantly improve its sorption capacity, selectivity and regenerative ability for Pb(II), and reduce the pomelo peel waste pollution.     

晶体弹塑性接触的微观机制

用分子动力学和金属固体的镶嵌原子模型研究了ｆｃｃ晶体Ｃｕ探针－基体微观接触的加载卸载规律、系统能量特性、基体微观应力场分布以及塑性失稳的缺陷形成机制。计算结果显示，在表面开始接触时，存在不稳定的突然粘着接触（ｊｕｍｐ－ｔｏ－ｃｏｎｔａｃｔ）。在压入状态（ｉｎｄｅｎｔａｔｉｏｎ）晶体的原子应力分布与宏观Ｈｅｒｔｚ理论的应力场相似。对弹性卸载，探针－基体分离的粘着拉应力接近Ｇｒｉｆｆｉｔｈ理论断裂强度     

Variational Inference Based Kernel Dynamic Bayesian Networks for Construction of Prediction Intervals for Industrial Time Series With Incomplete Input

Prediction intervals (PIs) for industrial time series can provide useful guidance for workers. Given that the failure of industrial sensors may cause the missing point in inputs, the existing kernel dynamic Bayesian networks (KDBN), serving as an effective method for PIs construction, suffer from high computational load using the stochastic algorithm for inference. This study proposes a variational inference method for the KDBN for the purpose of fast inference, which avoids the time-consuming stochastic sampling. The proposed algorithm contains two stages. The first stage involves the inference of the missing inputs by using a local linearization based variational inference, and based on the computed posterior distributions over the missing inputs the second stage sees a Gaussian approximation for probability over the nodes in future time slices. To verify the effectiveness of the proposed method, a synthetic dataset and a practical dataset of generation flow of blast furnace gas (BFG) are employed with different ratios of missing inputs. The experimental results indicate that the proposed method can provide reliable PIs for the generation flow of BFG and it exhibits shorter computing time than the stochastic based one.      

基于信令分析的BT流量预识别方法

P2P（Peer-to-Peer）系统在内容共享、即时通信、流媒体等领域获得了广泛应用。然而,P2P流量消耗了大部分网络带宽,造成网络拥堵,实现对P2P流量的有效识别和管理成为了一个十分热门的话题。针对BT的信令协议,分析了从Tracker服务器、DHT网络及通过PEX协议,获取节点列表的过程,提出通过相应报文中节点列表的解析,来达到BT流量预识别的方法。该方法能准确预知BT数据流的发生,较准确地对BT流量进行识别,并且有效减少系统开销。     

噪声影响的泛空间上的学习理论关键定理

关键定理是统计学习理论的重要组成部分,但目前其研究主要集中在概率空间上且假设样本不受噪声的影响。鉴于此,提出了泛空间上样本受噪声影响的期望风险泛函、经验风险泛函以及经验风险最小化原则的定义,给出并证明了泛空间上样本受噪声影响的学习理论的关键定理。     

Hyperpath-based vehicle routing and scheduling method in time-varying networks for airport shuttle service

It is very significant for a reasonable vehicle routing and scheduling in city airport shuttle service to decrease operational costs and increase passenger satisfaction. Most of the existing reports for such problems assumed that the travel time was invariable. However, the ever-increasing traffic congestion often makes it variable. In this study, considering the time-varying networks, a vehicle routing and scheduling method is proposed, where the time-varying feature enables the traveler to select a direction among all the Pareto-optimal paths at each node in response to the knowledge of the time window demands. Such Pareto-optimal paths are referred to hyperpaths herein. To obtain the hyperpaths, an exact algorithm is designed in this study for addressing the bi-criteria shortest paths problem, where the travel time comes to be discontinuous time-varying. Given the techniques that generate all Pareto-optimal solutions exhibiting exponential worst-case computational complexity, embedded in the exact algorithm, a computationally efficient bound strategy is reported on the basis of passenger locations, pickup time windows and arrival time windows. As such, the vehicle routing and scheduling problem viewed as an arc selection model can be solved by a proposed heuristic algorithm combined with a dynamic programming method. A series of experiments by using the practical pickup data indicate that the proposed methods can obtain cost-saving schedules under the condition of time-varying travel times.

     

Disturbance Observer‐Based Elegant Anti‐Disturbance Control for Stochastic Systems with Multiple Disturbances

Disturbance observer‐based elegant anti‐disturbance control (DOBEADC) scheme is proposed for a class of stochastic systems with nonlinear dynamics and multiple disturbances. The stochastic disturbance observer based on pole placement is constructed to estimate disturbance which is generated by an exogenous system. Then, composite DOBC and controller is designed to guarantee the composite system is mean‐square stable and its performance satisfies a prescribed level. Finally, simulations on an A4D aircraft model show the effectiveness of the proposed approaches.