No abstract

Botryosphaeria dothidea is an important fungal pathogen that causes apple ring rot, which can significantly reduce apple yield. Fungicide applications are the main control measure of apple ring rot worldwide. Pyraclostrobin is a quinone outside inhibitor (QoI) fungicide that has yet to be registered for control of B. dothidea in China. Baseline sensitivity of B. dothidea to pyraclostrobin (EC50 of mycelial growth inhibition) was assessed for 97 isolates collected in Shandong Province. The EC50 values ranged from 0.7010 to 7.1378 μg/ml with the mean value of 3.0870 μg/ml and displayed a unimodal frequency distribution. After cultured on fungicide-free PDA medium or on apples for multiple generations, the B. dothidea–resistant isolates (RST) remained resistant to pyraclostrobin, but exhibited similar virulence as the susceptible isolates (ST). Cross-resistance investigation revealed that pyraclostrobin was not cross-resistant to tebuconazole, flusilazole, carbendazim, and iprodione. Field evolution showed that pyraclostrobin at 200 and 250 g a.i./ha provided greater than 80% control efficacy against apple ring rot disease when applied as a therapeutic or preventive fungicide. The efficacy was similar to fungicides that have been registered for apple.

To provide continuous guiding information is one of the basic functions in road guide sign system. The representation model of guiding information based on road network topology is presented first in this paper; the meaning of guiding path in guide sign system is introduced then; the analysis model for finding continuous guiding path and the assessment index for guiding continuity is constructed. As an example, the road guide sign system in Guangzhou Zhujiang New Town is analyzed by the present model. It shows that the analysis model is feasible.

In coded-structured light three dimensional system, system calibration plays a vital role for the measurement accuracy. The camera calibration method is very mature, but the study about projector calibration is less. Therefore, this paper proposes a projector calibration method with simple calibration process and high accuracy. This method combines the Zhang’?s plane model calibration method with orthogonal phase shift coding. In calibration process, this paper uses phase shift coding pattern to establish the relationship of projector image and camera corner point coordinates. According to the image coordinates in the projector’?s perspective, we program and calculate the projector’?s internal and external parameters matrix based on the Zhang’?s plane model calibration toolbox. The results show that the proposed method is simple and flexible, the maximum relative error of the calibration parameters is 0.03%, and it meets the requirements of system calibration in medical or industrial fields.

Point cloud registration is necessary to acquire full-view data in coded SL three-dimensional measurement, based on single-view measured data. Aiming at surface feature of metal parts or human body, matching point pair construction principle, and transition matrix optimization method are analyzed. First, auxiliary-stereo-target registration principle and device are presented to establish matching point pair, and least-squares ill solution and iterative misconvergence caused by coplanar matching points can be avoided. Second, ICP method is adopted for acquiring transition matrix, and then mismatch point pair rejection method based on orthogonal Gray code principle is designed to increase iterative convergence. Experimental results show, registration error is about 0.8mm, close to that of global camera method and higher than that of surface method. This method has no influence on measured surface, and simplifies measurement device.