Search

To observe the expression of HPA, bFGF and VEGF in nasopharyngeal angiofibroma, and then explore its significance of inducing angiogenesis in the tumor's expansibility growth.The expression of heparanase, bFGF, VEGF and CD105 were examined in 30 (I - II period 9 cases, III - IV period 21 cases) samples from nasopharyngeal angiofibroma and 20 inferior turbinate tissues by immunohistochemical staining technique. The microvascular density (MVD) were measured by the immunohistostaining of CD105. The MVD was analyzed with the clinical stage.The positive rates of the HPA, bFGF and VEGF expression in JNA tissues were significantly higher than that in inferior turbinate group (P0.05). The positive rates of HPA, bFGF and VEGF expression in III - IV period were obviously higher than that in I - II period (P0.05). The expression of bFGF and VEGF in JNA tissues was respectively positive correlated with the HPA (r = by 0.499, 0.582, P0.05); In JNA tissues, the mean MVD in both HPA and bFGF positive group was higher than each one single positive group or both negative express group (P0.05). And the mean MVD in both HPA and VEGF positive group was higher than each one single positive group or both negative express group (P0.05).HPA can induce angiogenesis to promote tumor growth by releasing bFGF and VEGF. Targeting the HPA can be a new direction in JNA adjuvant treatment.

Take the fruit harvest robot experimental platform as background to research on the strategy of advancing harvest efficiency. Sample continuous and real-time fruit image by image processing, preprocess to detect the objective fruit, and then create an image coordinate system. Calculate oscillation frequency of the objective fruit with curve fitting of sample value. At the same time, get the depth of the objective fruit with visual and calculate the movement time of the Direct-acing joint to achieve the control of the end effector. The research will reduce the locating time, advance harvest efficiency of the harvest robot when spherical fruits like apple are oscillating.

The vision system of apple harvesting robot was researched and designed to make it possible for realizing automatic harvesting of apple. The vision system model is studied. The vision system of apple harvesting robot was designed by two aspects, including hardware composition and soft architecture. The VFW method was employed to realize the real-time image acquisition. The recognition of vision system is developed using the combination method of regional growth algorithm and color characteristics. The preliminary orientation of apple target was calculated by finding its centroid. At last, the performance of this version system was evaluated. The results showed that the developed vision system of apple harvesting robot successfully achieved the recognition and orientation of apple target. It was conclude that this version system was effective for realizing the automatic harvesting of apple.

This paper presents a direction of arrival (DOA) estimation algorithm in the presence of sensor mutual coupling, gain and phase uncertainties for a special nonuniform linear array (NLA). Based on our NLA model, more general linear array geometry can be exploited to improve upon estimation capacity, and the DOAs can be accurately estimated without any calibration sources. Moreover, our algorithm can also be applied to nonuniform circular array (NCA). Simulation results demonstrate the effectiveness of the algorithm.

A dual speed loop cascade control structure using the DC tachometer motor to constitute the inner speed loop, and using the rate gyro to constitute the outer stabilized loop is presented since there is shortcome in single speed loop servo control composed of rate gyro for LOS stabilization in opto-electronic tracking platform system. The functions of reducing inner friction disturbance and bating carrier turbulence are designed respectively. The aspects of the system performance and robustness are analyzed and compared with single speed loop control structure in detail. The inner speed loop adopts PI tuner to overcome the influence of nonlinearities caused by friction and mechanical resonances and a time optimal self-tuning PID control algorithm is developed to bate the carrier disturbance in outer stabilized loop. The proposed control structure and scheme based on DSP have been realized in a four-axis opto-electronic stabilized tracking platform. Experimental results can achieve higher stabilized precision and perfect control performance. The proposed control structure and method is effective and practicable in real practical applications.

In the robot vision system of the apple harvesting robot, the key is to recognize and locate the apple. To solve recognition questions such as high error rate, too much calculation and time consuming, a new recognizing method, support vector machine (SVM) is applied to improve recognition accuracy and efficiency. At first, vector median filter is used to remove the color images noise of apple fruit. Secondly, segmentation of the images based on region growing method and color properties is done. Then, color properties and shape properties of color image are extracted, and classification method of SVM for recognition of apple fruit is used. Experimental results indicate that the classification performance of support vector machine is better than that of neural networks. Recognition rate of apple fruit based on SVM of color and shape properties is higher than that of only using the color or shape properties.

The output power of photovoltaic (PV) power generation system is the nonlinear function of insolation, temperature and load, and thus the perturbation step of perturbation and observation (P&O) method should be regulated according to PV module working condition to improve the MPPT effect. P&O with fuzzy control, which can implement variable perturb step control, has good control effect, however this method is too complex for practical use. The relation of the perturbation step and the output power of PV module is analyzed that shows the step around maximum power point (MPP) should become small enough to eliminate power oscillation. This paper proposes a variable perturbation step P&O method according to this conclusion. This method utilizes the relation of the output power vs. voltage of PV module as the judge of step change. Simulation and experimental results show the proposed method has good stable and dynamic characteristics applied in PV power generation system.

A novel two-mode maximum power point tracking (MPPT) method, which combine with short-circuit current(SC) method and perturbation and observation (P&O) method, is presented to reduce the power pulsation around MPP and increase the usage effect of photovoltaic (PV) module. Two methods are used in different PV working points: short-circuit current method and Perturbation and Observation method. The PV module approach to MPP quickly under the control of short-circuit current based on linearity relationship between the short-circuit current and the optimal current of MPP when isolation changes, and then Perturbation and Observation method can make the PV module work near closely to MPP with small power pulsation. A novel method of short-circuit current acquired on line is presented to dissolve traditional SC disturbing the PV module working in this paper. Experimental results reveal that the PV power generation system has good steady performance and transient characteristics under the control of the presented method.

The output power of photovoltaic (PV) module is the function of module temperature and solar insolation, so it is necessary to track maximum power point (MPP) all the time. Among of presented MPPT methods, perturbation and observation (P&O) method has drawn more attractions due to its simple and high efficiency. However the PV module works around MPP, the output power of PV module will oscillate around it. The characteristics of PV modulewhich are discussed in detail, show different features of MPP sides is the reason of power oscillation. A novel asymmetric fuzzy control method, which adjusts the perturbation step according to the PV module work, is presented to reduce the power oscillation. Experimental results show the presented method can track MPP rapidly under solar insolation changing and reduce remarkable power oscillation.

A novel MPPT method, which adjusts the perturbation step according to the work point of photovoltaic (PV) module, is proposed to reduce the power oscillation around MPP. There is the nonlinear relation between the output power of photovoltaic module with temperature and load. The perturbation step is constant in traditional perturbation and observation (P&O) MPPT method. There is serious power oscillation around MPP under the control of P&O method. P&O with fuzzy control, which can implement variable perturb step control, has good control effect, however this method is too complex for practical use. The relation of the perturbation step and the output power of PV module is analyzed, which shows the step around maximum power point (MPP) should become small enough to eliminate power oscillation. This paper proposes a simple variable perturbation step P&O method according to this conclusion. This method utilizes the relation of the output power and voltage of PV module as the judge of step changing. Simulation and experimental results show the proposed method has good stable and dynamic characteristics, which is applied in PV power generation system.

A novel controller module based on DSP and CPLD is introduced according to the characteristic and requirement of servo control system. The hardware and software are discussed in detail. The high-speed DSP is acted as core for digital servo controller. The CPLD is adopted to achieve peripheral signal processing and control for logic and sequence. A function library is built according to C++ class structure and can be applied randomly. The experimental results show that the controller has the advantages of high reliability, opening structure, simple operation and can be applied with flexibility according to engineer requirement.

In this paper, the de-noising problem of night vision images is studied for apple harvesting robots working at night. The wavelet threshold method is applied to the de-noising of night vision images. Due to the fact that the choice of wavelet threshold function restricts the effect of the wavelet threshold method, the fuzzy theory is introduced to construct the fuzzy threshold function. We then propose the de-noising algorithm based on the wavelet fuzzy threshold. This new method can reduce image noise interferences, which is conducive to further image segmentation and recognition. To demonstrate the performance of the proposed method, we conducted simulation experiments and compared the median filtering and the wavelet soft threshold de-noising methods. It is shown that this new method can achieve the highest relative PSNR. Compared with the original images, the median filtering de-noising method and the classical wavelet threshold de-noising method, the relative PSNR increases 24.86%, 13.95%, and 11.38% respectively. We carry out comparisons from various aspects, such as intuitive visual evaluation, objective data evaluation, edge evaluation and artificial light evaluation. The experimental results show that the proposed method has unique advantages for the de-noising of night vision images, which lay the foundation for apple harvesting robots working at night.

In this chapter, an anisotropic damage model is established in strain space to describe the behavior of jointed rock masses under compression-dominated stress fields. The research work focuses on rate-independent and small-deformation behavior during isothermal processes. It is emphasized that the damage variables should be defined microstructurally rather than phenomenologically for jointed rock masses, and a secondorder “fabric tensor” is chosen as the damage variable. Starting from it, a one-parameter damage-dependent elasticity tensor is deduced based on tensorial algebra and thermodynamic requirements; An equivalent state is developed to exclude the macroscopic stress/strain explicitly from the relevant constitutive equations. Finally, some numerical results are worked out to illustrate the mechanical behavior of this model. In order to eliminate the complexity and arbitrariness in the formulation of phenomenological anisotropic model, systematic micromechanical analysis has been done on damage elasticity, damage evolution laws and micromechanics of different types of microdefects.

This paper gives a fault tree analysis on the operation of a carrying manipulator in a storehouse of solidified nuclear waste. By means of improving the man-computer interface and judging program for operation settings, and other measures, the operation validity of the manipulator is raised, and the working safety is insured. The validity of this method is proved by practice.