Showing papers by "Harbin Engineering University published in 2001"
TL;DR: Manganous hexacyanoferrate (MnHCF) supported on graphite powder was dispersed into methyltrimethoxysilane-derived gels to yield a conductive composite, which was used as electrode material to construct a renewable three-dimensional MnHCF-modifed electrode.
Abstract: Manganous hexacyanoferrate (MnHCF) supported on graphite powder was dispersed into methyltrimethoxysilane-derived gels to yield a conductive composite, which was used as electrode material to construct a renewable three-dimensional MnHCF-modifed electrode. MnHCF acts as a catalyst, graphite powder ensures conductivity by percolation, the silicate provides a rigid porous backbone, and the methyl groups endow hydrophobicity and thus limit the wetting section of the modified electrode. Cyclic voltammetry was exploited to investigate the dependence of electrochemical behavior on supporting electrolytes containing various cations. The chemically modified electrode can electrocatalytically oxidize L-cysteine, and exhibits a distinct advantage of polishing in the event of surface fouling, as well as simple preparation, good chemical and mechanical stability, and good repeatability of surface renewal.
42 citations
TL;DR: The chemically modified NiHCF-modified carbon ceramic electrode presented a good electrocatalytic activity toward the oxidization of thiosulfate and thus was used as an amperometric sensor for thiosolfate in the photographic waste effluent.
39 citations
TL;DR: In this article, the processing and technique of preparing nitrided iron ultrafine powder by the twice-nitriding method was studied, and the experimental results showed that γ′-Fe 4 N powder prepared by two-neighboring is highly pure, ultrafine and single phase.
30 citations
TL;DR: In this paper, a shadowing lemma for hyperbolic control flows is proved, and it is shown that hyper-bolic chain control sets are closures of control sets, which is the same as the shadowing theorem for control flows.
Abstract: A shadowing lemma for hyperbolic control flows is proved. A consequence is that hyperbolic chain control sets are closures of control sets.
26 citations
29 Jul 2001
TL;DR: Experiments prove that premature convergence can be overcome effectively by controlling PD during the GA's operation, and propose a kind of population diversity measurements and their computational formulas.
Abstract: Proposes a kind of population diversity (PD) measurements and their computational formulas. A quantitative relation between them is proved. The gene and individual are considered as separate units to investigate PD. A fuzzy genetic algorithm is designed using PD measurements developed, in which the fuzzy controller is used to adjust crossover rate and mutation rate dynamically to maintain the proper PD during the GA's operation. Experiments prove that premature convergence can be overcome effectively by controlling PD during the GA's operation.
24 citations
TL;DR: Based on white-light Michelson interferometric fiber optic sensing technique, a fiber optic two-dimensional (2D) strain sensing system is presented in this paper, which employs a light emitting diode (LED) as a broadband optical source and a single mode fiber that was fabricated in definite length as the strain sensor heads.
Abstract: Based on white-light Michelson interferometric fiber optic sensing technique, a fiber optic two-dimensional (2-D) strain sensing system is presented. The system employs a light emitting diode (LED) as a broadband optical source and a single mode fiber that was fabricated in definite length as the strain sensor heads. The light signals are guided by the same lead in and lead out fiber, so the changing caused by the environmental temperature fluctuation of the fiber path can automatically be compensated. The two independent fiber optic strain sensors were embedded in the cubic concrete specimens along the main axial (horizontal) direction and the vertical direction. The sensor gauge length is 103 and 115 mm, respectively. And its resolution is about ±5 micro strain (μ e ). It is in agreement with the conventional extensometer in the range of 0–6000 μ e .
22 citations
TL;DR: In this paper, a theoretical model has been developed to study the mechanical behaviors of the interface between an embedded optical fiber with coating material and a linear strain matrix, and the results show that the longitudinal stress and strain in the fiber optic sensor are different from that distributed in the host material and depend on the strain distribution and embedded length of the optical fiber as well as the material properties of the fiber coating.
22 citations
16 citations
01 Jan 2001
TL;DR: In this paper, a double-shell Structure with a hemi-spherical cap on the ends of the double shell was analyzed using FEM software ANSYS and BEM software SYSNOISE, where the normal modes and its frequency response, surface sound intensity distribution and sound pressure and sound energy flow in near field, the radiated sound power and radiation efficiency of sound power were given when the double-hell Structure is immersed in water, excited by point force source.
Abstract: The numerical analyses of vibration and sound radiation from a submerged elastic ring-stiffened double-shell with hemi-spherical cap on ends have been carried out by using FEM software ANSYS and BEM software SYSNOISE. The normal modes and its frequency response, surface sound intensity distribution and sound pressure and sound energy flow in near field, the radiated sound power and radiation efficiency of sound power are given when the double-shell Structure is immersed in water, excited by point force source. The directivity of sound in far field and the vibrational modes of this double-shell are also calculated.
11 citations
TL;DR: In this paper, the problems of scattering of plane SH-wave by a cylindrical hill of arbitrary shape is studied based on the methods of conjunction and division of solution zone.
Abstract: The problems of scattering of plane SH-wave by a cylindrical hill of arbitrary shape is studied based on the methods of conjunction and division of solution zone. The scattering wave function is given by using the complex variable and conformal mapping methods. The conjunction boundary conditions are satisfied. Furthermore appling orthogonal function expanding technique, the problems can finally be summarized into the solution of a series of infinite algebraic equations. At last, numerical results of surface displacements of a cylindrical arc hill and of a semi-ellipse hill are obtained. And those computational results are compared with the results of finite element method (FEM).
9 citations
TL;DR: In this article, a fiber-optic pre-embedded concrete bar (PECB) sensor for practical engineering construction of concrete structures is designed, taking into account the effects of the fiber protective coating.
Abstract: A fiber-optic pre-embedded concrete bar (PECB) sensor for use in the practical engineering construction of concrete structures is designed. Taking into account the effects of the fiber protective coating, a model is established. Based on the model, the temperature characteristics of fiber-optic PECB sensors are analyzed. Compared with the theoretical analyses, the temperature behavior of three typical cement-based matrix materials: cement paste, cement–sand mixture material and concrete pre-embedded bar sensors have been tested by using a white light fiber-optic interferometer sensing system.
TL;DR: In this paper, a large size PbWO4 crystal was grown by Czochralski method and the dopant Fe3+ in the raw material and the annealing technology affected the transmittance at 420 nm.
TL;DR: In this article, a photocell detects a laser beam passing through the propellant strand, and the cross-section of the laser beam is regulated so that the laser energy varies linearly along the height of the strand.
TL;DR: The fundamental functions of the signal processing circuits used in optical current sensing systems are: measuring the quantities of the Faraday rotation, compensating the fluctuations of optical intensity caused by the optical sources, band-pass filtering the signals to enhance the signal-to-noise ratio of the system outputs, and amplifying the signal to the assigned voltages as mentioned in this paper.
01 Jan 2001
TL;DR: In this paper, the ideal steady state programming with constant coolant average temperature and fresh steam pressure for marine PWR nuclear power plant is discussed and the feasibility of the ideal STP is proved.
Abstract: The ideal steady state programming with constant coolant average temperature and fresh steam pressure for marine PWR nuclear power plant is discussed It is necessary to regulate the coolant flow vs reactor load when the ideal steady state programming was carried out The optimum means to vary the motor speed of main coolant pump is using the AC transducer Through the evaluation of the core thermal limits and the heat transfer experiment of steam generator, the feasibility of the ideal steady state programming was proved
TL;DR: In this paper, the authors investigated robust control of lift feedback fin stabilizer on ship, the system math model is set up when a lift feedback stabilizer is adopted and the controller is designed by considering mixed sensitivity problem S/KS and the weighting function, at the same time, system simulation and its result are analyzed according to a ship.
TL;DR: In this paper, a fiber-optic slide sensor was designed for robust hands or intelligent mechanical clamping apparatuses, and the theoretical characteristic functions of the slide sensor were deduced and the experimental results were confirmed theoretical results.
01 Jan 2001
TL;DR: In this paper, the authors established the dynamic models of strap-down minehunting sonar array on moving base using the dynamics theory of rigid body and the ship motion and modeling theory.
Abstract: The dynamic models of strap-down minehunting sonar array on moving base are established using the dynamics theory of rigid body and the ship motion and modeling theory. Defining necessary coordinates, we expressed the velocity and angular velocity vector of the three shafts and the inertia matrix under the condition of parallel displacement and rotating of the coordinates. According to the momentum moment theorem the dynamic models of sonar array are carried out. At the same time, the characteristics of the models are analyzed. The simulation results indicate the correctness of the models. This gives the basis to design the stabilizing control system with high precision.
TL;DR: In this paper, the effect of reflection-induced phase retardance on the sensitivity of bulk glass current sensors was investigated theoretically by using a Jones' Matrix method, and it was shown that the theoretically expected maximum sensitivity may be approximately realized if the reflectioninduced phase degradation at each reflection is controlled less than 0.24 rad, provided the linear birefringence inside the sensing head is small.
01 Jan 2001
TL;DR: By using spatial directional information collected by combine sensor, the Coherent Interference Energy Suppress (CIES) technology, which can effectively suppress coherent interference and detect linear spectrum signal and wide-band continuous-spectrum signal as well, is presented as discussed by the authors.
Abstract: Comparing with traditional underwater acoustic system which only utilizes pressure information, combine sensor system processes pressure together with particle velocity information of sound field. More information certainly brings nicer processing result. By using spatial directional information collected by combine sensor, the Coherent Interference Energy Suppress (CIES) technology, which can effectively suppress coherent interference and detect linear spectrum signal and wide-band continuous-spectrum signal as well, is presented. Current research has shown favorite result, and further research is going on.
Journal Article•
TL;DR: In this paper, the results of experimental investigation on heat transfer and fluid pre-sure drop of spirally fluted titanium-tubes for steam con-densation are reported and analyzed based on a lot of experimental data.
Abstract: The results of experimental investigation on heat transfer and fluid pre ssure drop of spirally fluted titanium-tubes for steam con densation are reported and analyzedBased on a lot of experimental data,the empirical correlations of single-phase heat transfer coefficient,condensation heat transfer coeffic ient and pressure drop factors are givenThe results of experiments showed that s pirally fluted titanium-tube are better choice on heat transfer enhancement for the miniaturization of naval ste am condensers
Journal Article•
TL;DR: Based on the building of the time sequence model of fiber optic gyro drift data, the filter results are analyzed and fitted by Allan variance analyzing methods and Least Squares methods.
Abstract: Based on the building of the time sequence model of fiber optic gyro drift data, the fiber optic gyro drift data are processed using Kalman fiter, and the filter results are analyzed and fitted by Allan variance analyzing methods and Least Squares methods Then the error coefficients of drift data and data of filter output are obtained
Journal Article•
TL;DR: In this paper, the headsprings of core competence are the integration of core resources, which are divided into go-aheadism and passive core resources Chinese corporations are lack of goaheadism management ability in cultivating core competences by enhancing management.
Abstract: The headsprings of core competence are the integration of core resources, which are divided into go－aheadism and passive core resources Chinese corporations are lack of go－aheadism management ability in cultivating core competences By the end of this paper, cultivating core competences by enhancing management is suggested
TL;DR: In this article, the authors considered the statistical problem of the scattering of wideband pulses by a random layered medium at normal incidence in the framework of the wave approach in the space-time domain.
Abstract: The statistical problem of the scattering of wideband pulses by a random layered medium at normal incidence is considered in the framework of the wave approach in the space—time domain. Simulated correlation functions and power spectral densities of the backscattered field are presented. They extend the earlier findings concerning the backscattered field formation and also confirm and refine a number of conclusions drawn earlier from the behavior of the field’s statistical moments. The simulation technique is free from approximations commonly used in the statistical analysis of the propagation problems and can be used to study the statistical properties of the scattered field in a wide range of time intervals, as well as to find the limits of applicability of the approximate methods.
01 Jan 2001
TL;DR: In this article, a sliding mode control law is designed for the vehicle's motion, and the issues of propeller thrust distribution and control saturation are considered, and simulation results show that the strategy has nice performance of positioning and tracking ability.
Abstract: The concern of this paper is focused on the motion trajectory control of a six degree of freedom (DOF) underwater vehicle. First, the reasons that result in coupling between variables are given. Then, the vehicle's model is presented in view of reducing controls' side effects. A sliding mode control law is designed for the vehicle's motion. The issues of propeller thrust distribution and control saturation are considered. Simulation results show that the strategy has nice performance of positioning and tracking ability.
Journal Article•
TL;DR: In this article, a two-dimensional time-domain nonlinear strip theory is developed for predicting nonlinear hydrodynamic pressures and associated ship motions in large amplitude regular waves, which is solved with time domain free-surface Green function and source distributions on instantaneous wetted hull surface in incident wavesImproved numerical model and scheme are employed to avoid divergence and enhance efficiency during simulation procedures.
Abstract: A two-dimensional time-domain nonlinear strip theory is developed for predicting nonlinear hydrodynamic pressures and associated ship motions in large amplitude regular wavesThe problem is solved with time-domain free-surface Green function and source distributions on instantaneous wetted hull surface in incident wavesImproved numerical model and scheme are employed to avoid divergence and enhance efficiency during simulation proceduresThe emphasis is placed on the nonlinear hydrodynamic pressures on instantaneous body surface under incident waves and the consistence of ship motions and hydrodynamic forces that are achieved with a differential numerical schemeThe drawbacks of linear strip theory in predicting hydrodynamic pressures are pointed out with the comparisons of predicted and model test resultsThe nonlinear phenomena of hydrodynamic pressures with wave heights and the distributions of the positive and negative hydrodynamic pressures are illustrated with predicted results of a Wigley shipThe primary calculation shows encouraging prospect for further development of the theory and its application
23 Feb 2001
TL;DR: Based on the Michelson interferometer, fiber optic quasi-distributed strain-sensing techniques are demonstrated in this article, where related problem about the spatial division limitation of fiber optic sensors is discussed.
Abstract: Strain, deformation and temperature measurements constitute the most interesting parameters to be monitored in smart structures. White-light interferometry offers these performances even for long-term measurements. Based on the Michelson interferometer, fiber optic quasi-distributed strain-sensing techniques are demonstrated in this paper. Related problem about the spatial division limitation of fiber optic sensors is discussed.
26 Sep 2001
TL;DR: A novel coding method based on fuzzy vector quantization for polluted image by Gaussian white-noise is presented, which can not only achieve high compression ratio but also remove noise dramatically.
Abstract: In this paper a novel coding method which based on fuzzy vector quantization for polluted image by Gaussian white-noise is presented. By restraining the high frequency component of wavelet image, the noise is significantly removed. Then it could be coded by fuzzy vector quantization technique. The simulation result shows that this method can not only achieve high compression ratio but also remove noise dramatically.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.