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1

The impact of LNG carrier transit on fairway capacity

Li M., Mou J., XinSheng Z., Gong S.

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2018

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nr 56 (128)

63--70

EN

Liquefied natural gas (LNG), as one of the main sources of clean energy, has witnessed great growth in marine transportation in recent years. Due to the potential catastrophic consequences in case of a vessel traffic accident, the guidelines of the design of an LNG Port and the regulation of traffic management require that a mobile safety zone be set up for the transit of an LNG carrier, that is, a moving safety area around the carrier that excludes other ship traffic. To study the impact of a safety zone on channel capacity, this paper has presented a mathematical model to calculate the impact ratio of a large LNG ship on channel capacity considering different speeds and sailing modes. As a case study, an approach channel to a new LNG port that was developed in Yueqing bay, Zhejiang province, East China, has been analyzed during the concept design of the port with the aim of receiving ships with a capacity of 145,000 m3 . Based on the model, the impact ratio on the whole channel and the segmented channel when a carrier arrives at and leaves the berth has been calculated. The methodology can support the job of port design and vessel traffic management to improve the capacity, efficiency and safety of a waterway.

2

The cavitation nuclei transient characteristics of Lennard-Jones fluid in cavitation inception

Fu Q., Zhang B., Zhao Y., Zhu R., Liu G., Li M.

Polish Maritime Research

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2018

|

S 2

75--84

EN

In the field of ocean engineering, cavitation is widespread, for the study of cavitation nuclei transient characteristics in cavitation inception, we applied theoretical analysis and molecular dynamics (MD) simulation to study Lennard-Jones (L-J) fluid with different initial cavitation nuclei under the NVT-constant ensemble in this manuscript. The results showed that in cavitation inception, due to the decrease of liquid local pressure, the liquid molecules would enter the cavitation nuclei, which contributed to the growth of cavitation nuclei. By using molecular potential energy, it was found that the molecular potential energy was higher in cavitation nuclei part, while the liquid molecular potential energy changes greatly at the beginning of the cavitation nuclei growth. The density of the liquid and the surface layer changes more obvious, but density of vapor in the bubble changes inconspicuously. With the growth of cavitation nuclei, the RDF peak intensity increased, the peak width narrowed and the first valley moved inner. When cavitation nuclei initial size reduced, the peak intensity reduced, the corresponding rbin increased. With the decrease of the initial cavitation nuclei, the system pressure and total energy achieved a balance longer, and correspondingly, they were smaller. In addition, at the beginning of the cavitation nuclei growth, the total energy and system pressure changed greatly.

3

A novel method to extract vanadium from high-grade vanadium slag: non-salt roasting and alkaline leaching

Liu B., Meng L., Zheng S., Li M., Wang S.

Physicochemical Problems of Mineral Processing

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2018

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Vol. 54, iss. 3

657--667

EN

A new method using non-salt roasting-alkaline leaching to treat vanadium slag was proposed in this study. The V(III) in vanadium slag is oxidized to V(V) by roasting and the latter can be effectively leached out as vanadate by alkaline leaching. This method possesses distinct advantage of being able to treat high-grade vanadium slag. For the South Africa high-grade vanadium slag, the maximum vanadium recovery of 98% was achieved when the reaction conditions were roasting temperature of 850 °C, roasting time of 2 h, alkali concentration of 30 wt.%, leaching temperature of 210 °C, and leaching time of 2 h. The roasting and leaching mechanisms have been well elucidated based on the XRD and SEM analysis results. The phases transitions of vanadium slag were clearly presented. This work has laid the foundation for the industrial application of non-salt roasting-alkaline leaching and provided new insights into effective extraction of high-grade vanadium slag.

4

A numerical upper bound formulation with sensibly-arranged velocity discontinuities and orthotropic material strength behaviour

Li M., Füssl J., Lukacevic M., Eberhardsteiner J., Martin C. M.

Journal of Theoretical and Applied Mechanics

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2018

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Vol. 56 nr 2

417--433

EN

Numerical limit analysis allows for fast estimates of the collapse load of structures exhibiting ideal plastic material behaviour. In numerical upper bound formulations, the description of the unknown velocity field can be extended by introducing velocity discontinuities between finite elements. Through these additional degrees of freedom, localised failure modes may be approximated more accurately and better upper bounds can be obtained. In the existing formulations, such discontinuities are typically introduced between all elements and the description is restricted to isotropic failure behaviour. In this work, a general 3D upper bound formulation is briefly proposed, allowing the consideration of both isotropic and orthotropic yield functions within finite elements as well as at velocity discontinuities. The concept of “projecting” a stress-based orthotropic yield function onto a certain discontinuity is presented, giving a traction-based yield function which allows for a consistent description of the material strength behaviour across the interface. The formulation is verified by means of two classical examples, the rigid strip footing and the block with asymmetric holes. Furthermore, based on the computation of potential orientations of plastic flow localisation, a simple concept for a sensible arrangement of velocity discontinuities is proposed. It is shown that this concept performs very well for isotropic as well as anisotropic material strength behaviour. A feature of the present work is that, velocity jumps are allowed only across the prescribed finite element interfaces determined from the sensible discontinuity arrangement. Good upper bounds similar to those in the existing works are obtained with far fewer degrees of freedom.

5

An ant-based filtering random-finite-set approach to simultaneous localization and mapping

Li D., Zhu J., Xu B., Lu M., Li M.

International Journal of Applied Mathematics and Computer Science

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2018

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Vol. 28, no. 3

505--519

EN

Inspired by ant foraging, as well as modeling of the feature map and measurements as random finite sets, a novel formulation in an ant colony framework is proposed to jointly estimate the map and the vehicle trajectory so as to solve a feature-based simultaneous localization and mapping (SLAM) problem. This so-called ant-PHD-SLAM algorithm allows decomposing the recursion for the joint map-trajectory posterior density into a jointly propagated posterior density of the vehicle trajectory and the posterior density of the feature map conditioned on the vehicle trajectory. More specifically, an ant-PHD filter is proposed to jointly estimate the number of map features and their locations, namely, using the powerful search ability and collective cooperation of ants to complete the PHD-SLAM filter time prediction and data update process. Meanwhile, a novel fast moving ant estimator (F-MAE) is utilized to estimate the maneuvering vehicle trajectory. Evaluation and comparison using several numerical examples show a performance improvement over recently reported approaches. Moreover, the experimental results based on the robot operation system (ROS) platform validate the consistency with the results obtained from numerical simulations.

6

A comprehensive and practical reliability allocation method considering failure effects and reliability costs

Yu H., Zhang G., Ran Y., Li M., Wang Y.

Eksploatacja i Niezawodność

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2018

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Vol. 20, no. 2

244--251

EN

In view of the drawbacks in existing allocation methods which are incomplete considerations and poor practicality, a comprehensive fuzzy allocation method considering failure effects and reliability costs is proposed. Fuzzy linguistics and triangular fuzzy numbers are used to evaluate the uncertainty and subjective factors in allocation process. The traditional risk priority numbers (RPNs) are modified to overcome the shortages which are the same factor weights and equal difference of failure effects in original methods. State of the arts, components intricacy and working conditions are used to construct the reliability costs model, which solves the difficulties of costs statistics and avoids the sophisticated calculations which exist in current allocation methods. The relationship between reliability costs and potential risk of subsystem is studied and the value range of it is given in this paper. A case example is given to illustrative the scientificity and practicability of proposed allocation method.

PL

Ze względu na niedostatki istniejących metod alokacji, które nie dają pełnego obrazu problematyki i mają słabe zastosowanie w praktyce, w artykule zaproponowano kompleksową metodę alokacji opartą na logice rozmytej, uwzględniającą skutki uszkodzeń i koszty niezawodności. W pracy wykorzystano lingwistykę rozmytą i trójkątne liczby rozmyte do oceny niepewności i czynników subiektywnych w procesie alokacji. Zmodyfikowano tradycyjny wskaźnik liczby priorytetowej ryzyka (RPN), co pozwoliło na poprawę mankamentów charakteryzujących oryginalną metodę, t.j. takie same współczynniki wagowe i równoważność skutków uszkodzeń o różnym stopniu ciężkości. Na podstawie wiedzy o stanie techniki, złożoności komponentów i warunkach pracy, skonstruowano model kosztów niezawodności, który rozwiązuje trudności dotyczące sporządzania statystyki kosztów i pozwala uniknąć skomplikowanych obliczeń stosowanych w obecnych metodach alokacji. Zbadano związek między kosztami niezawodności a potencjalnym ryzykiem podsystemu, oraz podano jego zakres wartości. Prezentowane studium przypadku demonstruje możliwe zastosowania i efektywność proponowanej metody.

7

Fabrication of Nano- and Micron- Sized Spheres of CL-20 by Electrospray

Yan S., Li M., Sun L., Jiao Q., Huang R.

Central European Journal of Energetic Materials

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2018

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Vol. 15, no. 4

572--589

EN

The application of hexanitrohexaazaisowurtzitane (CL-20) in energetic materials will be expanded by its use as superfine particles. A method of fabricating nano- and micron-sized spheres of CL-20 by using electrospray is discussed. The effects of the precursor solution and the experimental conditions on the morphology and the crystal phase of the CL-20 particles are introduced. A variety of solvents was used to dissolve raw CL-20 for the preparation of the precursor solution with different CL-20 contents. The conductivity and viscosity of the precursor solutions were tested before the electrospray process. The electrostatic parameters were adjusted by changing the voltage and the distance between the nozzle and the plate. The morphology, crystal phase, mechanical sensitivity, density, and thermal stability of the raw CL-20 and the as-sprayed CL-20 samples were determined using scanning electron microscopy, X-ray diffraction, and differential scanning calorimetry (DSC). Furthermore, the density and the mechanical sensitivity were tested for the raw and the as-sprayed CL-20. DSC tests were conducted to compare the thermal stability and reactivity of the samples.

8

Different Ignition Responses of Powdery and Bulky 1,3,5-Triamino-2,4,6-trinitrobenzene (TATB) Based Polymer-bonded Explosives under Ultra-high Voltage Electrostatic Discharge

Lyu Z., Long X., Li Z., Dai X., Deng C., He S., Li M., Yao K., Wen Y.

Central European Journal of Energetic Materials

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2018

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Vol. 15, no. 2

283--298

EN

The electric spark induced ignition mechanism for explosives needs further study. The ignition of powdery and bulky TATB by electrostatic discharge (ESD) was investigated. Up to 200 kV ultra-high voltage ESD was applied to powdery and bulky explosives of two TATB-based polymer-bonded explosives (named PBX-1 and PBX-2). The results showed that the spark sensitivities of powdery and bulky explosives are extremely different for the same formulation. The 50% ignition voltages of powdery PBX-1 and PBX-2 were 10.8 kV and 8.5 kV, respectively, while the values for the bulky samples (tablets) were not less than 200 kV. Both heat and the electric field can be transmitted into the powdery samples, on the other hand only the electric field can be transmitted into the bulk samples. The electric field has a smaller contribution while the heat has a larger contribution to the ignition during an ESD, i.e., the thermal effect plays a main role in the ignition process. Our experimental results are in good agreement with recent results calculated by density functional theory.

9

Generalized Stockwell transform and SVD-based epileptic seizure detection in EEG using random forest

Zhang T., Chen W., Li M.

Biocybernetics and Biomedical Engineering

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2018

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Vol. 38, no. 3

519--534

EN

Purpose: Visual inspection of electroencephalogram (EEG) records by neurologist is the main diagnostic method of epilepsy but it is particularly time-consuming and expensive. Hence, it is of great significance to develop automatic seizure detection technique. Methods: In this work, a seizure detection approach, synthesizing generalized Stockwell transform (GST), singular value decomposition (SVD) and random forest, was proposed. Utilizing GST, the raw EEG was transformed into a time–frequency matrix, then the global and local singular values were extracted by SVD from the holistic and partitioned matrices of GST, respectively. Subsequently, four local parameters were calculated from each vector of local singular values. Finally, the global singular value vectors and local parameters were respectively fed into two random forest classifiers for classification, and the final category of a testing EEG was voted based on sub-labels obtained from the trained classifiers. Results: Four most common but challenging classification tasks of Bonn EEG database were investigated. The highest accuracies of 99.12%, 99.63%, 99.03% and 98.62% were achieved using our presented technique, respectively. Conclusions: Our proposed technique is comparable or superior to other up-to-date methods. The presented method is promising and able to handle with kinds of epileptic seizure detection tasks with satisfactory accuracy.

10

Biomechanical evaluation of tendon connection with novel suture techniques

Chen Z., Wang J., Wei J.- S., Hou Z.-Y., Li M., Chen Q.-X

Acta of Bioengineering and Biomechanics

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2018

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Vol. 20, no. 1

135--141

EN

Achilles tendon rupture is a severe injury with poor curative effect due to its anatomical characteristic and mechanical peculiarity. Internal fixation of limited loop (IFLL) with steel-wire has been applied on patients with tendon rupture to fix the broken ends before physical rehabilitation. The purpose of this study is to investigate the biomechanical property and radiological characteristic of such suture technique for the repairment of tendon rupture. Methods: Tendons of pigs’ hint feet were separated for the biomechanical study. Suture surgery was performed according to the protocol of IFLL. Biomechanical Testing Machine was adopted to conduct the biomechanical tensile load examination. The maximal load, elastic modulus and tendon stiffness of the stitched tendons with or without reinforcement were examined. Results: The maximum tensile load of the stitched tendons using IFLL reached 1/4 of the uninjured tendon’s maximum tensile load, indicating that such suture technique is capable of providing enough tension for the ruptured tendon. Surprisingly, tendons fixed with titanium wire showed the highest load tension, which was comparable to the undamaged tendon. Therefore, we found the biomechanical basis of using IFLL in effectively connecting the rupture ends of tendons. Conclusions: In conclusion, we provide biomechanical evidence for the use of IFLL in treatment of Achilles tendon rupture, by providing enough strength for the ankle function. Such suture technique could help the patients with better rehabilitation and reduced in-hospital stay after Achilles tendon injury.

11

Effects of preparation methods of mixed calcium and zinc thermal stabilizers derived from dimer fatty acid and tung-oil based C22 triacid on properties of PVC

Li M., Wang M., Li S., Huang K., Mao W., Xia J.

Polish Journal of Chemical Technology

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2017

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Vol. 19, nr 2

78--87

EN

Calcium and zinc salts of dimer fatty acids (DFA-Ca and DFA-Zn) were synthesized using direct neutralization and metathesis technologies, respectively. The adduct of maleic anhydride and methyl eleostearate (MAME) was also converted to the corresponding zinc soap (C22TA-Zn) and calcium soap (C22TA-Ca) by the two different synthetic routes. Mixed Ca/Zn salts between DFA-Ca and DFA-Zn, and between C22TA-Zn and C22TA-Ca were used as thermal stabilizers for poly(vinyl chloride) (PVC). The PVC thermal stability was determined using Congo red test, discoloration test, torque rheological analysis and TGA. Dynamic mechanical properties were also tested. Results indicated that the DFA-Ca/DFA-Zn thermal stabilizer from direct neutralization technology was found to be superior to that of the metathesis product. The C22TA-Ca/C22TA-Zn thermal stabilizer from direct neutralization method had overall superior thermal stability, and displayed modulus and glass transition comparable to that of metathesis product. Direct neutralization method was more excellent and convenient than metathesis technology.

12

Design, preparation and properties of novel flame retardant thermosetting vinyl ester copolymers based on castor oil and industrial dipentene

Mao W., Li S., Li M., Huang K., Xia J.

Polish Journal of Chemical Technology

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2017

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Vol. 19, nr 3

1--8

EN

A novel bio-based flame-retardant thermosetting vinyl ester resin monomer was synthesized from castor oil. The chemical structures of the monomer was characterized by FTIR and 1H-NMR. In order to improve its rigidity and expand its application in the field of bio-based materials, it was mixed with certain proportions of another reactive bio-based VER monomer, which had rigid and strong polar groups, and then a series of copolymers were prepared with thermal curing method. Then their tensile property, hardness, morphology of fractured surface, flame retardant property, DMA and thermostability were all investigated. The results indicated that the copolymers had relatively high tensile strength of 11.2 MPa, and the limiting oxygen index is above 23% in all prepared copolymers. DMA demonstrates that the glass transition temperature of the cured resins is up to 56.1°C. Thermogravimetric analysis shows that the copolymers have excellent thermal stability.

13

Characterization and Application of Al/Ni Reactive Multilayers in Exploding Foils

Wang T., Zeng Q., Li M.

Central European Journal of Energetic Materials

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2017

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Vol. 14, no. 3

547--558

EN

A self-propagating reaction achieved by initiating an Al/Ni reactive multilayer foil can generate significant heat. The interdiffusion rate of the reactants plays an important role in the foils properties and is mainly affected by premixing and the bilayer thickness. The present research aims to characterize Al/Ni multilayer foils and to investigate their influence on an exploding foil initiator. Samples with different bilayer thicknesses were fabricated by magnetron sputtering. The heat released and the flame velocity were characterized. Foils with a stored energy of about 1100 J/g were prepared and the heat released revealed the existence of a 4 nm premixing layer. The analytical model proposed by Mann was employed to match the measured flame velocities; the fitted model showed good agreement with the experimental results. To make a comparison, Cu and Al/Ni exploding foils with the same bridge size were fabricated and tested in the identical discharge circuit. The results showed that the energy deposition ratio of an Al/Ni foil was 67-69%, while the value for Cu was only 39-45%, which indicated that Al/Ni multilayers could effectively increase the energy utilization of an initiator. Larger average flyer velocities were also observed with the Al/Ni initiators.

14

Wpływ dodatku nanokrzemionki na mikrostrukturę i właściwości autoklawizowanego betonu komórkowego

Li M., Qian X., Peng H., Wu Z

Cement Wapno Beton

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2017

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R. 22/84, nr 4

320--327

PL

Praca dotyczy modyfikacji autoklawizowanego betonu komórkowego [ABK] dodatkiem nanokrzemionki. Wprowadzenie nanokrzemionki spowodowało wzrost wytrzymałości ABK nawet o ponad 20% dla 4,8% dodatku nanokrzemionki, pomimo tego, że wzrósł również stosunek wodno/spoiwowy mieszanek. Obecność nanokrzemionki spowodowała również spadek przewodnictwa cieplnego ABK nawet o 15% dla 4,8% dodatku nanokrzemionki. Powodem tego były zarówno zmiany porowatości i jej rozkładu jak również spadek przewodnictwa cieplnego samej nienapowietrzonej matrycy ABK modyfikowanej nanokrzemionką. Wyniki pokazały również, że obecność nanokrzemionki powoduje wzrost ilości i stopnia wykrystalizowania tobermorytu oraz fazy C-S-H.

EN

Different contents of silicon dioxide nanoparticles [SDN] were used in autoclaved aerated concrete [AAC]. Introduction of SDN results in compressive strength increase up to over 20% for 4.8% SDN dosage, despite increased water/solid ratio in the presence of SDN. SDN presence causes also decrease in thermal conductivity up to over 15% for 4.8% dosage of SDN. This is due to both changes in porosity and pore structure as well as decreased thermal conductivity of SDN modified unaerated hardened matrix. The results showed that SDN increase the amount and degree of crystallinity of tobermorite and C-S-H phase.

15

Application of MODWT and log-normal distribution model for automatic epilepsy identification

Li M., Chen W., Zhang T.

Biocybernetics and Biomedical Engineering

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2017

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Vol. 37, no. 4

679--689

EN

In this paper, a novel approach based on the maximal overlap discrete wavelet transform (MODWT) and log-normal distribution (LND) model was proposed for identifying epileptic seizures from electroencephalogram (EEG) signals. To carry out this study, we explored the potentials of MODWT to decompose the signals into time-frequency sub-bands till sixth level. And demodulation analysis (DA) was investigated to reveal the subtle envelope information from the sub-bands. All obtained coefficients were then used to calculate LDN features, scale parameter (s) and shape parameter (m), which were fed to a random forest classifier (RFC) for classification. Besides, some experiments have been conducted to evaluate the performance of proposed model in the consideration of various wavelet functions as well as feature extractors. The implementation results demonstrated that our proposed technique has yielded remarkable classification performance for all the concerned problems and outperformed the reported methods in terms of the universality. The major finding of this research is that the proposed technique was capable of classifying EEG segments with satisfied accuracy and clinically acceptable computational time. These advantages have make our technique an attractive diagnostic and monitoring tool, which helps doctors in providing better and timely care for the patients.

16

Water- and N-Induced Changes in Soil C:N:P Stoichiometry and Its Implications for N Limitation of a Desert Steppe Species, Glycyrrhiza uralensis

Huang J., Yu H., Zhang F., Li M., Lin H.

Polish Journal of Ecology

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2016

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Vol. 64, nr 2

241--254

EN

Changes in precipitation patterns and the deposition of atmospheric nitrogen (N) increase the possibility of altering soil carbon (C):N:phosphorus (P) stoichiometry through their effects on soil C and nutrient dynamics, especially in water- and N-limited ecosystems. We conducted separate 2-year watering and N addition experiments, and examined soil C:N:P stoichiometry, relative growth rate, and leaf N resorption traits of Glycyrrhiza uralensis Fisch in a desert steppe of northwestern China. Our objectives were to determine how soil C:N:P stoichiometry responded to climate change, and its indications for plant growth and N resorption. The results showed that additional water increased N loss and thus decreased N availability, resulting in high N resorption from senescing leaves of G. uralensis. N addition increased N availability, consequently reducing plant N dependence on leaf resorption. High relative growth rates occurred with intermediate N:P and C:N ratios, while high N resorption occurred with a low N:P ratio but a high C:N ratio. Our results indicate that soil C:N:P stoichiometry also could be a good indicator of N limitation for desert steppe species. Altered soil C:N:P stoichiometry affects the N strategy of plants, and will be expected to further influence the structure and function of the desert steppe community in the near future.

17

The Response of Wetland Plant Communities to Disturbance : Alleviation through Symmetric Disturbance and Facilitation

Xu F., Li M., Zhou D., Liu X., Wang R., Guo W.

Polish Journal of Ecology

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2016

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Vol. 64, nr 3

327--338

EN

The study pays attention to disturbances in early successional communities of wetland vegetation. We conducted artificial disturbances in a community of Suaeda salsa and Phragmites australis in the Yellow River Delta (China). Eight types of disturbances combining mowing treatments with species treatments were applied. Removal of the standing litters of P. australis or not was defined as mowing treatments, and removal of two species solo or both was defined as species treatments. We sampled 80 quadrats from the treatments plots at different intervals after the disturbance to investigate plant height, abundance, aboveground biomass, the distance between plants to reflect the effect of disturbance on composition, structure, productivity, and function of the plant communities. The strategies of seedling emergence and height growth differed as the canopy changed. Biomass contribution of different species, combined with disturbance intensity, was the main factors that affected the productivity. Homogeneity of disturbance was better for maintaining the functions of plant community in compared with the competitiveness (C), stress-tolerance (S) and ruderality (C-S-R) signatures with the control. Facilitations were reflected by the stagger arrangements in relative growth rates of the two species and in plant-plant interactions calculated by a modified function of competition. Adapting to symmetric disturbance and developing facilitative interactions are important requirements for early succession terrestrial vegetation to establish and stabilize in the seriously saline environments of wetlands.

18

Effects of various typical electrodes and electrode gels combinations on MRI signal-to-noise ratio and safety issues in EEG-fMRI recording

Gao D., Li M., Li J., Liu Z., Yao D., Li G., Liu T.

Biocybernetics and Biomedical Engineering

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2016

|

Vol. 36, no. 1

9--18

EN

To compare the effects of typical Ag/AgCl electrodes and electrode gels on MR images and assess safety hazards for patients during the electroencephalogram (EEG) data simultaneously with functional MRI (fMRI) recordings. So the measurements were conducted to compare the effects of three electrodes, three electrode gels and their combinations on the signal-to-noise ratio (SNR) of MR images at 3 T. Local temperature variation of the phantom for all conditions was also measured in the scanner. Results show that combination of silver-plated copper electrode and electrode gel (composed of carbomer as its main ingredient, with 85% moisture) is best for EEG-fMRI experiments. A sintered Ag/AgCl electrode could also be used as the material of EEG cap if infra-slow EEG-events need to be acquired in EEG-fMRI recording. Additionally, there is no significant heat induction detected. Overall, the methods and results of this study can be used for selecting appropriate EEG electrodes and electrode gels in EEG-fMRI experiments.

19

Automatic epilepsy detection using wavelet-based nonlinear analysis and optimized SVM

Li M., Chen W., Zhang T.

Biocybernetics and Biomedical Engineering

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2016

|

Vol. 36, no. 4

708--718

EN

Aiming at the problems of low accuracy, poor universality and functional singleness for seizure detection, an effective approach using wavelet-based non-linear analysis and genetic algorithm optimized support vector machine (GA-SVM) is proposed to deal with five challenging classification problems in this study. Instead of the traditional discrete wavelet transform (DWT), we attempt to explore the ability of double-density discrete wavelet transform (DD-DWT) to decompose the original EEG into specific sub-bands. The Hurst exponent (HE) and fuzzy entropy (FuzzyEn) are extracted as input features and then fed into two classifiers. On using these ranking non-linear features, the GA-SVM configured with fewer features is found to achieve the prominent classification performance for various combinations such as AB-CD-E, A-D-E, ABCD-E, C-E and D-E, achieving accuracies of 99.36%, 99.60%, 99.40%, 100% and 100%, respectively. The results have indicated that our scheme is not only appropriate in solving problems with multiple classes but also of lower complexity and better expansibility. These characteristics would make this method become an attractive alternative for actual clinical diagnosis.

20

The Static Unbalance Analysis and Its Measurement System For Gimbals Axes of an Inertial Stabilization Platform

Yang H., Zhao Y., Li M., Wu F.

Metrology and Measurement Systems

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2015

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Vol. 22, nr 1

51--68

EN

To reduce the influence of the static unbalance on an infrared missile guidance system, a new static unbalance measure system for the gimbals axes has been developed. Considering the coupling effects caused by a mass eccentricity, the static balance condition and measure sequence for each gimbal axis are obtained. A novel static unbalance test approach is proposed after analyzing the dynamic model of the measured gimbal axis. This approach is to drive the measured gimbal axis to do sinusoidal reciprocating motion in a small angle and collect its drive currents in real time. Then the static unbalance of the measured gimbal axis can be obtained by the current multi-cycle integration. Also a measuring system using the proposed approach has been developed. A balanced simulator is used to verify the proposed approach by the load and repeatability tests. The results show the proposed approach enhances the efficiency of the static unbalance measurement, and the developed measuring system is able to achieve a high precision with a greater stability.