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1

Volcanic ash cloud detection from MODIS image based on CPIWS method

Liu L., Li Ch., Lei Y., Yin J., Zhao J.

Acta Geophysica

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2017

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Vol. 65, no. 1

151--163

EN

Volcanic ash cloud detection has been a difficult problem in moderate-resolution imaging spectroradiometer (MODIS) multispectral remote sensing application. Principal component analysis (PCA) and independent component analysis (ICA) are effective feature extraction methods based on second-order and higher order statistical analysis, and the support vector machine (SVM) can realize the nonlinear classification in low-dimensional space. Based on the characteristics of MODIS multispectral remote sensing image, via presenting a new volcanic ash cloud detection method, named combined PCA-ICA-weighted and SVM (CPIWS), the current study tested the real volcanic ash cloud detection cases, i.e., Sangeang Api volcanic ash cloud of 30 May 2014. Our experiments suggest that the overall accuracy and Kappa coefficient of the proposed CPIWS method reach 87.20 and 0.7958%, respectively, under certain conditions with the suitable weighted values; this has certain feasibility and practical significance.

2

Vertical distribution of nearshore flow velocity

Li Ch., Fu X., Li R., Dai L., Chen P.

Polish Maritime Research

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2016

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S 1

104--108

EN

In this paper, a new exponential formed vertical distribution of nearshore flow velocity is constructed, which is simpler in form and more suitable for engineering application. The physical meaning of the new formula is more specific than that of Soulsby. Compared with those logarithmic formed ones, the new one does not need the maximum velocity and only needs the mean velocity in vertical, which gives it better engineering practicability. Apply the new formula to Jiangsu coastal area and compare the results with that of Soulsby whose results show the new formula agrees better with the measured flow velocity, which reasonably reflects the basic principles of vertical distribution of flow velocity.

3

Phase Transformation And Mechanical Properties Of Ti-12.1Mo-1Fe Alloy With Nano-Sized Precipitation

Lee D.-G., Seo J., Li Ch., Lee Y.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 2B

1393--1396

EN

Microstructural characterization and aging hardening behaviors of a new designed Ti-12.1Mo-1Fe alloy during solution treatment and aging were investigated in the present study. It is well known that when β-Ti alloys are generally under solution treatment or aging, α phases and ω phases appear or disappear dependent on heat treatment temperature and holding time. It is very necessary to understand the phase transformation phenomenon and to control the microstructure because these phases can control the drastic changes of the mechanical and physical properties of these alloys. According to the calculated [Mo]eq value and the microstructural observation, the β-transus temperature was about 780°. After the solution treatment, this alloy was composed of the β-phase and the microstructure mainly consisted of the equiaxed β grains with the average size of 25 μm. ω phases which were precipitated during aging process, played a more important role to the hardening effect than α phases. The highest hardness value of Ti-12.1Mo-1Fe alloy showed in the condition of the aging temperature of 450°. The hardening due to ω-phase precipitation can lead to a high hardness about 480 Hv but the coarse α-phase result in hardness below 300 Hv.

4

Remote Sensing Monitoring of Volcanic Ash Clouds Based on PCA Method

Li Ch., Dai Y., Zhao J., Zhou S., Yin J., Xue D.

Acta Geophysica

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2015

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Vol. 63, no. 2

432--450

EN

Volcanic ash clouds threaten the aviation safety and cause global environmental effects. It is possible to effectively monitor the volcanic ash cloud with the aid of thermal infrared remote sensing technology. Principal component analysis (PCA) is able to remove the inter-band correlation and eliminate the data redundancy of remote sensing data. Taking the Eyjafjallajokull volcanic ash clouds formed on 15 and 19 April 2010 as an example, in this paper, the PCA method is used to monitor the volcanic ash cloud based on MODIS bands selection; the USGS standard spectral database and the volcanic absorbing aerosol index (AAI) are applied as contrasts to the monitoring result. The results indicate that: the PCA method is much simpler; its spectral matching rates reach 74.65 and 76.35%, respectively; and the PCA method has higher consistency with volcanic AAI distribution.

5

BTR-4 borehole thermal response testing equipment and application research

Sun Y., Wang Q., Li Ch., Chen Ch., Guo W.

Zeszyty Naukowe. Górnictwo / Politechnika Śląska

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2009

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z. 287

255-261

EN

. An equipment for in-situ testing the mean thermal conductivity of formation and borehole resistance is introduced in this paper, which provide a new approach to test the parameters of rock and soil for designing the ground source heat pump system(GSHPS). The parameters are tested under heat extraction situation of a single U-pipe heat exchanger and heat injection situation of a double U-pipe heat exchanger by using the device, and the conclusions are drawn that the mean thermal conductivity of formation of heat injection situation is larger than heat extraction situation, the calculating result of thermal conductivity of line source model is greater than cylinder source model, and the borehole thermal resistance of the double U-pipe is less than the single U-pipe heat exchanger.

PL

W artykule zaprezentowano aparaturę do badań in-situ średniej wartości przewodnictwa cieplnego i oporu cieplnego skał w otworach. Umożliwia ona nowe podejście do oceny parametrów skał i gruntów dla potrzeb projektowania systemów pomp ciepła (GSHPS). Stwierdzono między innymi, iż średnia wartość przewodnictwa cieplnego zmierzona w reżimie iniekcji ciepła jest wyższa od tejże, określonej w reżimie poboru ciepła. Wartości obliczone dla modelu źródła liniowego są wyższe niż dla modelu cylindrycznego.