We mainly report an efficient approach to optimize the design of beaconless spatial laser acquisition. In order to analyze the influence of vibration environment on the beaconless spatial acquisition, a demonstration of an efficient method will be presented to simulate the level of satellite platform vibration. An important power spectral density (PSD) model of satellite platform vibration used by the European Space Agency is introduced. Then through LABVIEW, a simulated vibration waveform is generated, and the simulated PSD has a basic consistency with the in-orbit measurement spectral line, referring to the design of the filter, generating the Gaussian white noise sequence, filtering the pseudorandom signal and the whole processing procedure of parameter matching. The variation interval of the vibration amplitude is from −100 to 40 μrad. Then, the model of beaconless acquisition is proposed, which uses the spiral scan pattern, laser with a divergence angle of 80 μrad scan in an uncertainty cone (UC), and also the scan coupled with the simulated vibration is given. Through the beaconless acquisition program, the vibration is suppressed between −10.7 and 5.9 μrad; when the overlap factor is selected as 10%, it does not produce any leakage scanning area. It can be used for a wide variety of platforms. This new method will be good for analysis and test of beaconless spatial acquisition algorithm. Finally, the description of acquisition duration, which mainly includes the fast steering mirror spiral scan and the mechanical rotary table step scan, is introduced. And the corresponding optimal selection method of sub-region is proposed; the design of 1.6-mrad scanning pattern with 7 × 7 sub-regions in the 8-mrad acquisition UC is given. Through the actual measurement, the acquisition time is 18.21 s, the tracking error is better than 0.4 μrad.

Objective The current study was to evaluate the prevalence of increased carotid artery intimal-medial thickness (IMT) and carotid plaque in young individuals and factors associated with increased IMT and carotid plaque were also assessed. Methods Individuals between 18 and 44 years old who underwent an annual health examination and without cardiovascular disease were included. The value of IMT ≥0.1 cm was defined as increased IMT and IMT ≥0.15 cm was defined as carotid plaque. Based on the IMT, participants were divided into normal and abnormal groups. Results A total of 551 individuals were included and the mean age was 38.9 years old, with women accounting for 32.5% (n=179) and 238 (43.2%) individuals with abnormal IMT. Those with abnormal IMT was older, more likely to be male and smoking, had higher blood pressure (BP) and body mass index (BMI). Individuals with abnormal MIT also had worse lipid profiles, higher serum levels of fasting plasma glucose (FPG), HbA1c, homocysteine, and uric acid. Age, male sex, elevated systolic and diastolic BP, BMI, HbA1c, FPG, triglyceride, total cholesterol, LDL-C, homocysteine, and uric acid were positively correlated with IMT, while HDL-C was negatively correlated with IMT. Factors associated with increased IMT and carotid plaque included age, male sex, BMI, triglyceride, LDL-C, homocysteine, uric acid, and smoking. Conclusion Among apparent healthy young individuals, the prevalence of increased IMT was high and there were several factors associated with increased IMT. Further studies are needed to evaluate how to be better in preventing the development of subclinical atherosclerosis among young individuals.

The causes of voids in the soldering layer during vacuum reflow soldering of semiconductor laser devices are investigated, as are the movement and change laws of bubbles in the voids under different reflow chamber settings. An ultrasonic scanner is used to test and experiment with a series of 1064 nm wavelength semiconductor lasers. A technique for detecting the void rate based on the wavelength difference is proposed based on the association between the device wavelength, junction temperature, and voids. The average void rate error when comparing measured and calculated values is just 1.5%, demonstrating the validity of this estimation technique for defining the void rate of the device and providing a theoretical and practical reference to analyze the void rate of the device.

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