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A novel type of nonlinear robust control strategy is proposed in view of uncertain nonlinear factors, such as hysteresis, creep, and high-frequency vibration, of piezoelectric actuators (PEAs). This strategy can be used for the precise trajectory tracking of PEAs. The Bouc–Wen dynamic model is reasonably simplified to facilitate engineering application. The hysteresis term is summarized as an unknown term to avoid its nonlinear parameter identification. The controller robustness is achieved due to the nonsingular terminal sliding mode control, and the online estimation of unknown disturbances is realized because of the delay estimation technology; thus, no prior knowledge of the unknown boundary of the system is required. The precision robust differentiator is used to estimate the speed and acceleration signals in real time on the basis of the obtained displacement signals. The closed-loop stability of the system is proved by the Lyapunov criterion. Experimental results show that the proposed control strategy performs better than the traditional time-delay estimation control in terms of control accuracy and energy conservation. Therefore, the proposed control strategy can play an important role in the micro/nanofield driven by PEAs.

The electric power distribution grid directly serves the ordinary users, the stability and reliability of which are crucial to production and life. The traditional operation and maintenance of the distribution grid is based on experience and cannot scientifically predict the state of line faults. In this paper, stepwise regression is used to screen out 8 key influencing factors of line faults, and principal component analysis is performed to find the risk value of each line; so that establishes multiple linear and exponential regression equations for the line risk value. According to the existing data, the risk of the line is predicted, and the GABP neural network model is built so as to accurately predict the risk value of the line.

In order to deal with the energy crisis and environmental pollution, renewable energy power generation in the world has been rapid development. At present, the most widely used is solar energy and wind energy, but also caused a serious problem of abandoning light and wind. Hydrogen energy has become an ideal carrier of electric energy storage due to its high efficiency, clean and renewable characteristics. Electrolytic water hydrogen production technology with renewable energy as power source is one of the most promising energy conversion methods. This paper briefly analyzes the current situation of power generation and consumption of renewable energy in China in recent years, and then expounds the characteristics, principles, development status and improvement methods of alkaline, proton exchange membrane and high temperature solid oxide electrolytic water hydrogen production technology, and demonstrates its application prospect in the field of renewable energy power generation and energy storage with examples.

An automobile intelligent auxiliary control system performance for comity pedestrians is analysed. For safety reasons, a car safety distance model which can distinguish pedestrians at the front zebra crossing line is proposed. The important features of the active protective comity pedestrian integrated control system are derived, which can accurately identify pedestrians or cyclists in front of you and distinguish safety behaviour characteristics. According to the system feedback, active protection measures are adopted. A control system based on the combination of infrared radar probe ranging system and image processing recognition system is studied. The innovative research on car avoiding pedestrians focuses on both the behaviour characteristics of the driver and the pedestrian. Dual protection of longitudinal anti-collision comity pedestrians and horizontal pedestrian protection early warning protection can be carried out through the system. The intelligent auxiliary control system is a control system that can ensure the safety of pedestrians at non-traffic signal intersections. The system embodies more intelligent and humane, and also provides innovative ideas for the research and development of new products.

Low- and medium-frequency noise from ship cabins is difficult to control effectively. Excessive noise can seriously affect the acoustic stealth performance of ships. A novel membrane-type acoustic metamaterial is proposed in this paper with light weight and good sound insulation performance at low frequencies. The sound insulation performance of the metamaterial structure is analysed by using the acoustic-solid coupling module in COMSOL software. Then, the ability to change the sound insulation performance of membrane-type acoustic metamaterials with cell structure and material parameters is obtained. The research results in this paper provide powerful technical support for noise control in ship cabins.

Various novel SrBi2Ta2O9:Tm3+ blue-emitting materials were achieved via solid-state synthesis. The structure and phase purity of prepared SrBi2Ta2O9:xTm3+ (x = 0.005-0.30 mol) were examined by X-ray powder diffraction. The surface morphology of SrBi2Ta2O9:0.01Tm3+ were studied by scanning electron microscopy. Photoluminescence properties were systematically explored under the monitoring emission (λem = 468 nm) and excitation (λex = 303 nm) spectra. The optimum mole ratio of as-synthesized phosphors was 0.01 mol. The concentration quenching mechanism in the SrBi2Ta2O9 host was due to electric multipole interaction. Particularly, the chromaticity coordinates (0.1334, 0.0474) of SrBi2Ta2O9:0.01Tm3+ are near to those of the commercial BaMgAl10O17:Eu2+. These results validated the SrBi2Ta2O9:Tm3+ phosphor can be utilized good blue-emitting candidate for W-LEDs.

A series of Ca2YTaO6: Tm3+ blue-emitting phosphors were firstly prepared by the solid-state method. The phase formations and purity of Ca2YTaO6: xTm3+ (x = 0.3%-5% mol) were verified by X-ray powder diffraction. The morphological characteristics of Ca2YTaO6: 0.005Tm3+ were detected by scanning electron microscopy (SEM). Photoluminescence properties were discussed by emission (λem = 460 nm) and excitation (λex = 359 nm) spectra. The critical doping concentration of the products was 0.005 mol. The proposed concentration quenching mechanism in Ca2YTaO6 materials was the electric multipole interaction. Besides, the color coordinates (0.1408, 0.0891) of Ca2YTaO6: 0.005Tm3+ were located in blue region. The results suggested the Ca2YTaO6: Tm3+ phosphors can be promising blue-emitting components for the WLED applications.

Carbon nanofibers (CNFs) were used as admixtures to modify traditional concrete, and carbon nanofibers reinforced concrete (CNFC) with fiber volume fraction of 0%, 0.1%, 0.2%, 0.3% and 0.5% were prepared. The dynamic splitting tensile tests of concrete with different fiber volume contents under five loading rates were carried out by using the Φ100 mm split Hopkinson pressure bar (SHPB) test device. Based on the observation and analysis of the failure modes of the specimens, combined with the energy change rate of incident wave, the failure characteristics of CNFC under dynamic splitting tensile load are expounded. The results show that: the addition of CNFs has a certain inhibition effect on the dynamic splitting tensile failure of concrete; the failure modes of the specimens are the central failure along the loading direction; with the increase of the energy change rate of incident wave, the damage degree of the specimen is gradually aggravated.

Using the slotting method to process the interface of ordinary mortar, based on ordinary mortar specimens, new and old mortar bonding specimens were prepared, and the bond strength test was carried out. The effect of interface roughness on the bonding strength of VAE rubber powder modified mortar and styrene-acrylic emulsion modified mortar was tested, and then the interfacial bonding properties of polymer modified mortar were studied. The test results show that the bonding strength of polymer-modified mortar increases with the increase of interface roughness; in engineering applications, the interface can be properly chiseled to increase the interface roughness, which is beneficial to the bonding of polymer-modified mortar firm. At the same time, the application prospects of VAE rubber powder modified mortar in the field of concrete anti-corrosion, and the application prospect of styrene-acrylic emulsion modified mortar in the repair and freeze-thaw damage of concrete structure and anti-seepage treatment are prospected.

We in order to study the influence of intake parameters on the combustion and emission of natural gas-diesel dual-fuel Marine engine, AVL_FIRE simulation software was used to build a high pressure cycle model of combustion chamber based on 4190ZLC-2 Marine medium-speed diesel engine. The accuracy of the model was verified by comparing the simulation data with the cylinder pressure curve obtained from bench test. The influence of intake parameters on combustion and emission performance was studied by model simulation. The results show that the combustion quality can be improved by increasing the intake temperature, and the power performance and economy can be improved by appropriate intake temperature. Increasing the intake pressure has the effect of supercharging, appropriately increasing the intake pressure can obtain better power and emission, and can also avoid the rough operation of dual-fuel diesel engine and reduce the noise

Low-frequency acoustic scatterings from a finite cylindrical shell are numerically analyzed by FEM. The simulation results show that the acoustic-scattering field in waveguide has lots of frequency-related sidelobes, while no sidelobes exist in free space at low frequencies. The simulation also indicates that the module value in waveguide can be almost 20 dB larger than that in free space at low frequency, which is caused by the ocean boundaries. We also demonstrate that when the incident wave direction is normal to the target at low frequency, the target strength will be maximum and the distribution of the acoustic-scattering field is axisymmetric about the incident waving direction. Meanwhile, the acoustic-scattering field is also related to the impedance of the seabed, and the change of the impedance makes just a little contribution to the scattering field. Finally, the influence of different target locations is analyzed, including the targets near the sea surface, seabed and the middle region of the ocean waveguide, respectively. From simulation results, it is evident that the distribution of the acoustic-scattering field at low frequency has a little difference, which is smaller than 0.5 dB with various target locations, and the change is frequency and boundary-related.

In this paper, through the electromechanical control modification of 4190 ZLC-2 diesel, the electronic fuel injection model is established by AMESim simulation software, and the high pressure circulation model of butanol/diesel dual fuel engine is established by AVL-FIRE software, the appropriate initial parameters module and corresponding boundary conditions are set. At the condition of low-temperature combustion through exhaust gas recirculation (EGR), in the optimization scheme studying the influence of butan blending ratio and EGR rate on diesel engine emissions. The result shows that the addition of butanol can improve the low temperature combustion, reducing the formation of CO and soot. The introduction of EGR can achieve low temperature combustion and significantly reduce NO emissions. The optimal parameter set for parameter matching is obtained: B20/EGR12.5 %.

The discourse system is an important carrier of ideology, and ideology must rely on the discourse system to express and disseminate. The discourse system of ideological and political education carries the content and expression of ideological and political education, and the degree of its improvement and the role it plays directly determine the effectiveness of curriculum ideological and political education. The research on discourse in ideological and political education in foreign language education mainly focuses on what the connotation of discourse in ideological and political education is, which elements it includes, how it operates and plays a role in teaching practice, how educators complete discourse conversion and carry out effective discourse dissemination, and so on. Through these researches, the discourse system of ideological and political education in foreign language education is established. Combined with Marxist theory, discourse criticism theory, and communication theory, the basic concepts and content of the discourse system of ideological and political education are clarified, and the basic elements and operation process of the discourse system of ideological and political education are analyzed.

This paper presents a comprehensive optimization approach for enhancing the performance of a methanol/diesel Exhaust Gas Recirculation (EGR) engine. Initially, a hybrid fuel engine combustion chamber model was developed using AVL-FIRE software, and the simulated results were compared with the values obtained from bench tests. An orthogonal experimental design was employed to optimize five key factors, namely methanol blending ratio, EGR rate, injection advance angle, intake pressure, and intake temperature. Evaluation indexes were established, with indicated power and NO emissions assigned weights of 0.35 and 0.65, respectively. The optimal parameter combinations were determined as follows: methanol blending ratio (a1=20%), EGR rate (a2=12.5%), injection advance angle (a3=16.6°CA), intake temperature (a4 = 315.15 K), and intake pressure (a5=0.173 MPa). The indicated power of the optimized configuration reached 47.8 kW, slightly lower than the original 55 kW, while the NO emission mass fraction decreased to 1.9×10-4%, representing a significant reduction of 77.6% compared to the original value of 8.5×10-4%. This optimization methodology demonstrates the effective reduction of NO emissions without compromising power performance in methanol/diesel EGR engines.

In order to further investigate the performance of the butanol-diesel dual-fuel engine, this paper uses the 4190ZLC-2 marine medium-speed diesel engine as a prototype and establishes a dual-fuel engine high-pressure cycle model using AVL-FIRE simulation software. The injection advance angle was set to 16.6°, 18.6°, 20.6° and 22.6° respectively, and its effect on the performance of the dual-fuel engine was investigated by varying the injection advance angle. The results show that as the injection advance angle increases, the incylinder pressure and temperature also increase. When the injection advance angle is 22.6°CA, compared with the original engine, CO emission is reduced by 16.8%, NO emission is increased by 7.4%, carbon smoke emission is reduced by 16.9%, and the indicated power is 52.6kW, which is increased by 1.8%.

Fatigue analysis of hybrid wind turbine towers between cut in wind speed and cut out wind speed are demonstrated. Nominal stress method and miner liner accumulated damage theory are adopted. Through the analysis of the results, comparative research on effect of parameters of aspect ratio, height ratio and unequal legs for fatigue properties of hybrid wind turbine towers. The results show that the optimal range of aspect ratio of hybrid towers is 1/6~1/4, the optimal range of height ratio of hybrid towers is 0.60~0.67. Fatigue analysis of hybrid towers, should select the right junction of leeward towers and the S-N curve from EN 1993-1-9.The effect of unequal legs for fatigue properties of hybrid towers can be neglected.

Positive psychology is capable of not only meeting the developing requirements of humans, but also establishing effective scientific virtues. Under the impact of positive psychology, colleges and universities have exerted certain positive effects and social values in conducting mental health education for college students, thereby optimizing the overall mode of mental health education and realizing its high efficacy and scientificization. This essay provides a comprehensive analysis of the significance of mental health education to the development of college students, adopts a positive psychology stance, and examines relevant research strategies in an effort to enhance the mental health of college students.

Past research has shown that because tourism itself is a product of a gendered society, its processes are gendered in terms of construction, presentation, and consumption. This study examines how these websites shape the image of the Mosuo people and the Mosuo culture by analyzing texts in Chinese tourism websites. Ten representative Chinese tourism websites were selected for this study, and all relevant texts that could be retrieved were analyzed manually. All samples selected were officially published and represent only the attitudes of the tourism websites. The results of the study show that there are a large number of feminized or sexualized descriptions in the texts about the Mosuo people and the Mosuo culture provided by Chinese tourism websites. The language used on tourism websites is shaped by discourses of patriarchy and sexuality and is intended for heterosexual male tourists.

The limitation of seismic resolution makes the interpretation of fault end locations based on seismic data unclear, and often can only be predicted qualitatively by human, which makes the combination relationship of breakpoints near or below seismic resolution unclear. The breakpoint combination rate is generally low, which affects the development injection and recovery relationship and remaining oil distribution.