Autor: Gu, X. - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: The influence of ship rolling motion on take-off aerodynamic characteristics of aircraft
Autorzy:: He, Z.
Sun, X.
Gu, X.
Tematy:: ship rolling motion
ski-jump take-off
Meshless method
WALE turbulence model
aerodynamic characteristics; Pokaż więcej
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:: https://bibliotekanauki.pl/articles/259257.pdf Link otwiera się w nowym oknie
Opis:: Ship motion is an important factor affecting on the safety of ski-jump take-off. The simplified frigate ship SFS1 was numerically simulated, and the results were compared with the experimental data, the feasibility of the calculation method was verified; Meshless method and WALE turbulence model were used to simulate the process of aircraft skijump take-off, aerodynamic characteristics under different rolling conditions during the aircraft ski-jump take-off process were presented. The results showed that: the influence of ship rolling motion on lift coefficient, drag coefficient and pitching moment was small, side force and rolling moment were greatly affected by rolling motion; the region of downwash with the maximum speed was about 10 m from the bow; the safety of ski-jump take-off was greatly affected when aircraft was close to the bow within 20 m.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Ship Course Following and Course Keeping in Restricted Waters Based on Model Predictive Control
Autorzy:: Liu, H.
Ma, N.
Gu, X. C.
Tematy:: Ship Movement, Multiple-Input Multiple-Output (MIMO)
Very Large Crude Carrier (VLCC)
Model Predictive Control (MPC)
Linear Quadratic Regulator (LQR)
course
restricted waters
safety at sea; Pokaż więcej
Wydawca:: Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Powiązania:: https://bibliotekanauki.pl/articles/116264.pdf Link otwiera się w nowym oknie
Opis:: Ship navigation safety in restricted water areas is of great concern to crew members, because ships sailing in close proximity to banks are significantly affected by the so-called ship-bank interaction. The purpose of this paper is to apply the optimal control theory to help helmsmen adjust ships’ course and maintain the target course in restricted waters. To achieve this objective, the motion of a very large crude carrier (VLCC) close to a bank is modeled with the linear equations of manoeuvring and the influence of bank effect on the ship hydrodynamic force is considered in the model. State-space framework is cast in a Multiple-Input Multiple-Output (MIMO) system, where the offset-free model predictive control (MPC) is designed for course following and the linear quadratic regulator (LQR) is used for course keeping. Simulation results show that the control methods effectively work in ship course following and course keeping with varying ship-bank distances and water depths. The advantage of adopting speed variation as the second control input is obvious.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Numerical study of hydrodynamic derivatives and course stability under ship-bank interaction
Autorzy:: Liu, H.
Ma, N.
Gu, X. C.
Tematy:: safety at sea
ship-bank interaction
Reynolds-Averaged Navier-Stokes (RANS)
hydrodynamic derivatives
hydrodynamics
Planar Motion Mechanism (PMM)
Circulating Water Channel (CWC)
User Defined Functions (UDF); Pokaż więcej
Wydawca:: Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Powiązania:: https://bibliotekanauki.pl/articles/116925.pdf Link otwiera się w nowym oknie
Opis:: Since ship-bank interaction affects the manoeuvrability of a ship navigating close to a bank, the determination of hydrodynamic derivatives is of great importance to assess the ship manoeuvrability. To obtain the hydrodynamic derivatives of the KVLCC2 model ship with different water depths and ship-bank distances, the simulation of PMM tests are carried out using an unsteady Reynolds-Averaged Navier–Stokes (RANS) based solver. Hybrid dynamic mesh technique is proposed to realize the simulation of pure yaw tests in confined water. Studies on the grid convergence and time-step-size convergence are firstly performed. Hydrodynamic derivatives for the ship in different water depths and ship-bank distances are compared. The course stability is investigated based on time-domain simulations and eigenvalue analysis, and the results show that the ship-bank interaction and shallow water effect have a remarkable influence on the course stability.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Selective flotation of siderite and quartz from a carbonate-containing refractory iron ore using a novel amino-acid-based collector
Autorzy:: Gu, X.
Zhu, Y.
Li, Y.
Han, Y.
Tematy:: flotation
quartz
hematite
siderite
refractory iron ores
molecular simulation; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/110222.pdf Link otwiera się w nowym oknie
Opis:: A novel and highly-efficient amino-acid-based collector, α-ethylenediamine lauric acid (α-EDA-LA), was studied to selectively beneficiate carbonate-containing refractory hematite ores. Single mineral and synthetic mixture flotation tests were carried out to investigate its floating performance. Zeta potential, fourier transform infrared spectroscopy (FTIR) and Density Functional Theory-based molecular simulation were used to identify the adsorption mechanism. The flotation results showed that quartz could be collected effectively at pH 11.0-12.0 in the reverse flotation. For siderite, the recovery peaked at 83.4% at pH 8.0, where siderite presented different floatability from magnetite and hematite. Exploiting such difference, the separation of siderite could be achieved. Zeta-potential measurements showed that α-EDA-LA adsorption on the surfaces of siderite and quartz decreased the corresponding zeta potentials at pH of 8.0-10.0 and 8.0-12.0, respectively. This means the adsorption overcome the electrostatic repulsion between α-EDA-LA and the mineral surfaces. The molecular simulation indicated that no chemisorption took place between α-EDA-LA and quartz. FTIR analysis suggested that α-EDA-LA was adsorbed on quartz via hydrogen bonding. The adsorption of α-EDA-LA on siderite surface was dominated by chemisorption, while further enhanced by hydrogen bonding. This study filled the gap in the research on siderite flotation reagents and its adsorption mechanism.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: A generalized equivalent temperature model in a time-varying environment
Uogólniony model temperatury równoważnej w zmiennym w czasie otoczeniu
Autorzy:: Sun, L.
Gu, X.-H.
Song, P.
Di, Y.
Tematy:: przyspieszone badania starzenia
temperatura równoważna
przechowywanie w warunkach naturalnych
krzywa degradacji
oringi nitrylowe
accelerated degradation test
equivalent temperature
nature storage
degradation path
rubber Orings; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Powiązania:: https://bibliotekanauki.pl/articles/301556.pdf Link otwiera się w nowym oknie
Opis:: Accelerated degradation test at high temperature level is a common method to accelerate the degradation of products by elevating temperature, and the obtained degradation data are then used to obtain the estimate of the performance at normal temperature after extrapolating the degradation through accelerating model. However, the normal temperature is ever-changing rather than constant. Therefore, a generalized equivalent temperature model based on power law degradation path is proposed to establish a connection between accelerated degradation data and degradation data at normal temperature. The model takes the equal degradation measure as a principle and the conclusion is demonstrated that the increments of the degradation under the same magnitude, same time and different orders of temperature stresses are same. The result shows that the empirical equivalent temperature model is a special case of the proposed model. The accuracy of the proposed model is finally demonstrated by a case study of nitrile rubber O-rings.
Przyspieszone badania degradacji (badania starzeniowe) prowadzone w warunkach wysokiej temperatury stanowią powszechnie stosowaną metodę przyspieszania starzenia produktów poprzez podwyższanie temperatury. Otrzymane w takich badaniach dane degradacyjne wykorzystuje się do szacowania wydajności produktu w temperaturze normalnej na zasadzie ekstrapolacji. Głównym ograniczeniem tej metody jest fakt, że normalna temperatura nie jest stała lecz zmienia się w czasie. Dlatego też, aby skorelować dane z przyspieszonej degradacji z danymi dotyczącymi starzenia w normalnej temperaturze, zaproponowaliśmy uogólniony model temperatury równoważnej oparty na krzywej degradacji opisanej prawem potęgowym. W modelu przyjęto zasadę równego stopnia degradacji i wykazano, że przyrosty degradacji przy tej samej wartości i czasie działania naprężeń termicznych różnego rzędu są takie same. Wyniki pokazują, że empiryczny model temperatury równoważnej jest szczególnym przypadkiem proponowanego przez nas modelu. Trafność opisanego w pracy modelu wykazano na podstawie studium przypadku dotyczącego uszczelek nitrylowych, tzw. oringów.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Flotation behavior and separation mechanism of quartz and iron minerals in α-bromolauric acid reverse flotation system
Autorzy:: Han, Y.
Guo, W.
Zhu, Y.
Wei, Y.
Gu, X.
Tematy:: quartz
separation
reverse flotation
iron minerals
α-Bromolauric acid; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Powiązania:: https://bibliotekanauki.pl/articles/949733.pdf Link otwiera się w nowym oknie
Opis:: A new type collector α-Bromolauric acid (α-BLA) had been proved to be an efficient collector for quartz flotation. However, the effects of α-BLA on the flotation behavior of iron minerals and quartz-iron separation had not been investigated. In this study, collector α-BLA was synthesized in the laboratory. The flotation behavior of quartz, hematite and magnetite under α-BLA reverse flotation system were investigated and the separation mechanism of quartz-irons was studied by contact angle, zeta-potential and infrared spectroscopy. The results showed that the optimum flotation pH was 11.5 for quartz, 6.45 for hematite and 6.97 for magnetite. The best α-BLA concentrations was 75 mg/dm3 for quartz flotation, 125 mg/dm3 for hematite and magnetite flotation. The activator CaCl2 had little effect on the flotation of hematite and magnetite, but the minimum dosage 50 mg/dm3 of activator CaCl2 was necessary for quartz flotation. On the contrary, starch had no effect on the flotation of quartz, while the recoveries of magnetite and hematite tended to be 0% as starch concentration more than 80 mg/dm3. The separation mechanism of quartz from iron minerals under α-BLA reverse flotation system was that the starch could be selectively adsorbed on the surface of hematite and magnetite in the form of strong hydrogen bond adsorption. However, the same adsorption of starch did not occur on the surface of quartz, so the α-BLA can be successfully adsorbed on the surface of activated quartz to make the quartz strongly hydrophobic, and then to be floated out.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Effect of Ageratina adenophora on hepatic and pulmonic pathological lesions in horses
Autorzy:: Gu, X.L.
Dai, F.Y.
Xiao, X.
Li, G.Z.
Zhang, L.M.
Qu, W.J.
Tematy:: Ageratina adenophora
liver
lung
horse
toxicity; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/2087129.pdf Link otwiera się w nowym oknie
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Hybrid methodology of degradation feature extraction for bearing prognostics
Metodyka hybrydowa ekstrakcji cech degradacji do zastosowań w prognozowaniu czasu życia łożysk
Autorzy:: Gu, H.
Zhao, J.
Zhang, X.
Tematy:: ekstrakcja cech
degradacja
sygnał
łożysko
feature extraction
degradation
signal
bearing; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Powiązania:: https://bibliotekanauki.pl/articles/302055.pdf Link otwiera się w nowym oknie
Opis:: Hybrid methodology of degradation feature extraction was presented which may enable prediction of remaining useful life of a product. In this methodology, firstly, the signal was de-noised by wavelet analysis. Then the autoregressive model was used to remove the discrete frequencies from de-noised signal. Further, the residual signal which mainly contained impulsive fault signal was enhanced by minimum entropy deconvolution filter. The kurtosis was extracted which was taken as the feature for prognostics. At last, the empirical mode decomposition was used to reduce fluctuation of feature value and to extract the trend content. A case study was presented to verify the effectiveness of the proposed method.
Przedstawiono hybrydową metodę ekstrakcji cech degradacji, która umożliwia przewidywanie pozostałego okresu użytkowania produktu. W tej metodyce, sygnał został najpierw odfiltrowany z wykorzystaniem analizy falkowej. Następnie, za pomocą modelu autoregresyjnego usunięto z pozbawionego szumów sygnału częstotliwości dyskretne. W dalszej kolejności, sygnał resztkowy, który zawierał głównie impulsowy sygnał uszkodzenia został wzmocniony z zastosowaniem filtru dekonwolucji minimum entropii. Obliczono kurtozę, którą przyjęto jako cechę w procesie prognozowania. Na koniec, zastosowano empiryczną dekompozycję sygnału (EMD) w celu zmniejszenia wahań wartości cechy oraz w celu ekstrakcji trendu. Studium przypadku demonstruje efektywność proponowanej metody.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Speech emotion recognition based on sparse representation
Autorzy:: Yan, J.
Wang, X.
Gu, W.
Ma, L.
Tematy:: speech emotion recognition
sparse partial least squares regression SPLSR
SPLSR
feature selection and dimensionality reduction; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/177778.pdf Link otwiera się w nowym oknie
Opis:: Speech emotion recognition is deemed to be a meaningful and intractable issue among a number of do- mains comprising sentiment analysis, computer science, pedagogy, and so on. In this study, we investigate speech emotion recognition based on sparse partial least squares regression (SPLSR) approach in depth. We make use of the sparse partial least squares regression method to implement the feature selection and dimensionality reduction on the whole acquired speech emotion features. By the means of exploiting the SPLSR method, the component parts of those redundant and meaningless speech emotion features are lessened to zero while those serviceable and informative speech emotion features are maintained and selected to the following classification step. A number of tests on Berlin database reveal that the recogni- tion rate of the SPLSR method can reach up to 79.23% and is superior to other compared dimensionality reduction methods.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Study on Fluorescence Characteristic of a Complex Probe οf CdSe Quantum Dots Coupling with Thiazole Orange
Autorzy:: Fei, X.
Jia, G.
Wang, J.
Gu, Y.
Tematy:: 73.63.Kv
78.55.-m
78.67.-n; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1537765.pdf Link otwiera się w nowym oknie
Opis:: CdSe quantum dots were synthesized using thioglycolic acid as stabilizer in aqueous solution under $N_{2}$. The UV-vis spectrometry and fluorescence spectra indicate that the bimodal quantum dots were formed and the optical band gaps are about 650 nm and 750 nm, respectively. The quantum dots coated with TO were prepared in room temperature, and the fluorescence characteristic was studied. The result showed that the peak shift of quantum dots fluorescence spectra can mainly be due to the change of the capping layer, resulting in the confinement energy change. This is vital for the investigating on of the forming process and mechanisms of the combination of thiazole orange dye and quantum dots.
Dostawca treści:: Biblioteka Nauki

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