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1

The importance of low-carbon landscape design in rural tourism landscape

Li Jun, Gan Jialiang

Ecological Chemistry and Engineering. S

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2022

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Vol. 29, nr 3

319--332

EN

The paper aims to study the importance of low-carbon landscape design based on rural tourism landscape. First of all, after sorting out and researching the relevant reviews of low-carbon landscapes, taking rural landscapes as the research object, a rural landscape planning and design framework based on the perspective of low-carbon construction is proposed. Then, Xiwuli Village is used as an example to carry out the application practice of specific strategies and the carbon emissions before and after the planning and design are calculated and compared. After the low-carbon planning and design of the rural landscape, the net carbon footprint and the total carbon footprint were significantly reduced, confirming the low-carbon effect of the planning and design strategy. Finally, according to the actual situation of the scenic spot, it points out the principles and policy suggestions that must be followed in the development of low-carbon rural tourism. Experiments show that: the net carbon footprint and total carbon footprint are significantly reduced, which proves the actual effect of low-carbon design and the effect of low-carbon planning and design strategy.

2

Short-term wind power combined prediction based on EWT-SMMKL methods

Li Jun, Ma Liancai

Archives of Electrical Engineering

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2021

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Vol. 70, nr 4

801--817

EN

Since wind power generation has strong randomness and is difficult to predict, a class of combined prediction methods based on empirical wavelet transform (EWT) and soft margin multiple kernel learning (SMMKL) is proposed in this paper. As a new approach to build adaptive wavelets, the main idea is to extract the different modes of signals by designing an appropriate wavelet filter bank. The SMMKL method effectively avoids the disadvantage of the hard margin MKL method of selecting only a few base kernels and discarding other useful basis kernels when solving for the objective function. Firstly, the EWT method is used to decompose the time series data. Secondly, different SMMKL forecasting models are constructed for the sub-sequences formed by each mode component signal. The training processes of the forecasting model are respectively implemented by two different methods, i.e., the hinge loss soft margin MKL and the square hinge loss soft margin MKL. Simultaneously, the ultimate forecasting results can be obtained by the superposition of the corresponding forecasting model. In order to verify the effectiveness of the proposed method, it was applied to an actual wind speed data set from National Renewable Energy Laboratory (NREL) for short-term wind power single-step or multi-step time series indirectly forecasting. Compared with a radial basic function (RBF) kernel- based support vector machine (SVM), using SimpleMKL under the same condition, the experimental results show that the proposed EWT-SMMKL methods based on two different algorithms have higher forecasting accuracy, and the combined models show effectiveness.

3

Evaluation of the diference in water quality between urban and suburban rivers based on self organizing map

Jiang Yaqi, Gui Herong, Li Chen, Chen Jiayu, Chen Chen, Wang Chunlei, Zhao Honghai, Guo Yan, Xu Jiying, Li Jun, Qiu Huili

Acta Geophysica

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2021

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Vol. 69, no. 5

1855--1864

EN

Urban rivers play an important role in maintaining the urban aquatic ecological environment, and there are bound to be differences in the water environment quality and pollution sources due to different locations of urban rivers. Therefore, this paper selects the urban river (Tuo River) and the suburban river (Bian River) in Suzhou City, Anhui, China, as the research objects. Based on the understanding of the hydrogeochemical characteristics of these two rivers, the self-organizing map is used to identify the main control factors that affect the water quality of the two rivers. The results showed that both the Bian river and Tuo river were weakly alkaline. The average content of conventional ions in Tuo river is less than that of Bian river (except HCO3 −); the water of Bian river was of Na–SO4–Cl type, and the water of Tuo river was mainly of Na–HCO3 type, with the minority was of Na–SO4–Cl type; Silicate weathering is an important source of conventional ions in the water of these two rivers; agricultural non-point source pollution is the main source of pollutants in Bian river, while Tuo river was mainly affected by natural factors, and human activities had little impact.

4

Calculation of the dynamic characteristics of ship’s aft stern tube bearing considering journal deflection

Yang Hongjun, Li Jun, Li Xiaolong

Polish Maritime Research

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2020

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nr 1

107--115

EN

Dynamic properties are vital for the working reliability of aft stern tube bearings. However, the determination of such properties currently involves several simplifications and assumptions. To obtain its dynamic characteristics accurately, the aft stern tube bearing was divided into several bearing segments. The oil film reaction force was considered in the calculation of shaft alignment, and the journal deflection and actual oil film thickness were obtained accordingly. Subsequently, the perturbed Reynolds equation was solved using the finite difference method when the dynamic characteristics of journal bearings with finite width were evaluated. Then, a calculation program was developed and verified by comparing with the results of other studies. Finally, the dynamic characteristics were calculated under different revolutions. The results showed that the stiffness at the vertical direction of the aft stern tube bearing was several times that of the horizontal direction and varied with the revolutions of the shafting system. These findings can provide the foundation for the precise calculation of the journal trajectory under dynamic conditions, as well as for the evaluation of the oil film thickness. Moreover, the results led to favorable conditions for the accurate calculation of the shafting whirling vibration.

5

Dominant species drive seasonal dynamics of the fish community in the Min estuary, China

Li Jun, Kang Bin

Oceanological and Hydrobiological Studies

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2020

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Vol. 49, No. 1

34--48

EN

Fishery resources are currently facing multiple stresses such as overfishing, pollution and climate change. Looking into processes and mechanisms of the dynamic fish community through detailed quantitative analyses contributes to effective conservation and management of fishery resources. The Min estuary plays an important role in maintaining fisheries in southeastern coastal China, therefore the fish community in the brackish area was investigated and analyzed in this study. A total of 127 species belonging to 91 genera, 49 families and 14 orders were sampled in 2015. Eight indices reflecting four aspects of fish communities were determined, i.e. species richness, species evenness, heterogeneity and taxonomy. Differences between the indices were nonsignificant, suggesting that the use of a single diversity descriptor could not provide a full explanation. Nine dominant species in the Min estuary showed seasonal turnover by rational use of resources and co-occurring species showed correspondingly adequate habitat preferences and feeding habits to avoid competition. The species Harpadon nehereus occurred as the dominant species in three seasons except spring. High values of niche overlap among common or rare species and lower values of niche overlap among all dominant species effectively brought the diversity of the fish community into a state of equilibrium.

6

Identifcation of gas bearing reservoirs based on the simultaneous inversion of NMR dual TW logging data

Li Jianwei, Zou Youlong, Li Jun, Pan Heping, Hu Song, Su Junlei, Wang Lei, Liu Jun, Guo Yue

Acta Geophysica

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2020

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Vol. 68, no. 3

667--674

EN

In this paper, we propose a method for obtaining two-dimensional T1–T2 spectrum from simultaneous inversion of the MRIL-Prime tool, dual-TW logging data, in order to improve the accuracy in identifying gas-bearing reservoirs. This paper was accomplished by analyzing the theoretical feasibility of the method, verifying its efectiveness by numerical simulation, and then applying the method to actual logging interpretations to identify gas-bearing reservoirs. The practical application results show that this method can circumvent misidentifcation of reservoirs due to the presence of large pores—a known issue with using a one-dimensional diferential spectrum—and efectively identify gas-bearing reservoirs with low resistivity.

7

Review of Lattice Boltzmann Method Applied to Computational Aeroacoustics

Shao Weidong, Li Jun

Archives of Acoustics

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2019

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Vol. 44, No. 2

215--238

EN

This paper presents the research studies carried out on the application of lattice Boltzmann method (LBM) to computational aeroacoustics (CAA). The Navier-Stokes equation-based solver faces the difficulty of computational efficiency when it has to satisfy the high-order of accuracy and spectral resolution. LBM shows its capabilities in direct and indirect noise computations with superior space-time resolution. The combination of LBM with turbulence models also work very well for practical engineering machinery noise. The hybrid LBM decouples the discretization of physical space from the discretization of moment space, resulting in flexible mesh and adjustable time-marching. Moreover, new solving strategies and acoustic models are developed to further promote the application of LBM to CAA.