Browsing by Author "Zhang, Yong"

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Assessment of the feasibility of vessel trains in the ocean shipping sector
(2024-05) Liu, Lei; Liu, Kaiyuan; Shibasaki, Ryuichi; Zhang, Yong; Zhang, Mingyang
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
This paper introduces the concept of vessel train, a new mode in maritime transport offering both environmental and economic advantages. The study provides a framework for analyzing the economic feasibility of vessel train in ocean shipping, focusing on four different scenarios to evaluate its impact on navigation speed and productivity for both round-trip and year-long operations. Using the container ship route from Yangshan Port to the Port of Piraeus as a case study, the research compares vessel train with traditional shipping methods by categorizing shipping costs. It also includes a sensitivity analysis considering factors like route length, frictional resistance reduction, and variations in the container freight index, fuel prices, and carbon tax rates. The findings indicate that vessel train can reduce transportation costs and fuel emissions. The paper concludes that vessel train could significantly contribute to a competitive and sustainable future in shipping.
The dissipative Talbot soliton fiber laser
(2024-03-15) Zhang, Heze; Du, Yueqing; Zeng, Chao; Sun, Zhipei; Zhang, Yong; Zhao, Jianlin; Mao, Dong
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Talbot effect, characterized by the replication of a periodic optical field in a specific plane, is governed by diffraction and dispersion in the spatial and temporal domains, respectively. In mode-locked lasers, Talbot effect is rarely linked with soliton dynamics since the longitudinal mode spacing and cavity dispersion are far away from the self-imaging condition. We report switchable breathing and stable dissipative Talbot solitons in a multicolor mode-locked fiber laser by manipulating the frequency difference of neighboring spectra. The temporal Talbot effect dominates the laser emission state-in the breathing state when the integer self-imaging distance deviates from the cavity length and in the steady state when it equals the cavity length. A refined Talbot theory including dispersion and nonlinearity is proposed to accurately depict this evolution behavior. These findings pave an effective way to control the operation in dissipative optical systems and open branches in the study of nonlinear physics.
Functionalization mediates heat transport in graphene nanoflakes
(2016-04-29) Han, Haoxue; Zhang, Yong; Wang, Nan; Samani, Majid Kabiri; Ni, Yuxiang; Mijbil, Zainelabideen Y.; Edwards, Michael; Xiong, Shiyun; Sääskilahti, Kimmo; Murugesan, Murali; Fu, Yifeng; Ye, Lilei; Sadeghi, Hatef; Bailey, Steven; Kosevich, Yuriy A.; Lambert, Colin J.; Liu, Johan; Volz, Sebastian
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
The high thermal conductivity of graphene and few-layer graphene undergoes severe degradations through contact with the substrate. Here we show experimentally that the thermal management of a micro heater is substantially improved by introducing alternative heat-escaping channels into a graphene-based film bonded to functionalized graphene oxide through amino-silane molecules. Using a resistance temperature probe for in situ monitoring we demonstrate that the hotspot temperature was lowered by ∼28°C for a chip operating at 1,300 W cm-2. Thermal resistance probed by pulsed photothermal reflectance measurements demonstrated an improved thermal coupling due to functionalization on the graphene-graphene oxide interface. Three functionalization molecules manifest distinct interfacial thermal transport behaviour, corroborating our atomistic calculations in unveiling the role of molecular chain length and functional groups. Molecular dynamics simulations reveal that the functionalization constrains the cross-plane phonon scattering, which in turn enhances in-plane heat conduction of the bonded graphene film by recovering the long flexural phonon lifetime.
Is the spatial-temporal dependence model reliable for the short-term freight volume forecast of inland ports? A case study of the Yangtze River, China
(2021-09-08) Liu, Lei; Zhang, Yong; Chen, Chen; Hu, Yue; Liu, Cong; Chen, Jing
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
The purpose of this study is to investigate whether spatial-temporal dependence models can improve the prediction performance of short-term freight volume forecasts in inland ports. To evaluate the effectiveness of spatial-temporal dependence forecasting, the basic time series forecasting models for use in our comparison were first built based on an autoregression integrated moving average model (ARIMA), a back-propagation neural network (BPNN), and support vector regression (SVR). Subsequently, combining a gradient boosting decision tree (GBDT) with SVR, an SVR- GBDT model for spatial-temporal dependence forecast was constructed. The SVR model was only used to build a spatial-temporal dependence forecasting model, which does not distinguish spatial and temporal information but instead takes them as data features. Taking inland ports in the Yangtze River as an example, the results indicated that the ports’ weekly freight volumes had a higher autocorrelation with the previous 1–3 weeks, and the Pearson correlation values of the ports’ weekly cargo volume were mainly located in the interval (0.2–0.5). In addition, the weekly freight volumes of the inland ports were higher depending on their past data, and the spatial-temporal dependence model improved the performance of the weekly freight volume forecasts for the inland river. This study may help to (1) reveal the significance of spatial correlation factors in ports’ short-term freight volume predictions, (2) develop prediction models for inland ports, and (3) improve the planning and operation of port entities.