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An innovative method for synthesizing optimum difference patterns of the spherical sensor array is introduced, along with a sidelobe tapering technique. Firstly, we suggest employing the spherical harmonics of degree ±1 to synthesize the spherical array difference pattern; secondly, we study the mapping relationship between the difference pattern of the spherical sensor array and the difference pattern of the uniformly spaced linear array (ULA) with odd-numbered elements; finally, we enhance the Zolotarev difference pattern, which is a counterpart to the Dolph–Chebyshev sum pattern that traditionally allows synthesis only for ULA with even-numbered elements. Our modification extends its applicability to synthesize difference patterns for ULA with odd-numbered elements. Leveraging the optimal difference pattern, a generalized Bayliss difference pattern synthesis method designed for the ULA with odd-numbered elements is further proposed. To illustrate the effectiveness of our approach, we present several design examples through experimental simulation.

Objective To analyze the comprehensive factors causing adverse reactions to apheresis platelet donation(ARAPD), so as to provide references for effective prevention of ARAPD. Methods The 272 cases of ARAPD from 2012 to 2019 in Lanzhou were statistically analyzed, and factors that induced ARAPD were studied. Statistical analysis were performed according to the gender, nationality, occupation, age, weight, donation units, and number of donations. Results As to the factors inducing ARAPD, anticoagulant reactions accounted for the first(32.4%, 88/272). Women and students were prone to develop ARAPD. Among all age groups, 18~25 years old were most likely to develop ARAPD(53.68%, 10 572/35 265). The incidence of ARAPD were significantly different by ages and weights(P

Objective To study the current situation of apheresis platelets collection in various regions of Gansu province by comparing and analyzing relevant data from blood stations in 14 prefecture-level cities of Gansu province. Methods The units of collected platelets and rate of double-dose collection in 13 regional blood stations and 1 provincial blood center from 2016 to 2020, as well as the clinical supply and demand was statistically analyzed. Results From 2016 to 2020, the total units of platelets collected by 13 blood stations and 1 blood center in Gansu increased from 11 255 U to 15 270 U, with the increase rate at 35.7% in 5 years, and mainly were collected by the provincial blood center (74.57%, 50 253/ 67 392). Although the rate of double-dose collection in the province showed a steady upward trend, only 3 blood stations realized annual double-dose collection more than 20%. There was still a gap of about 10% between supply and clinical needs. Conclusion Although the number of platelet collections and units in each blood station in Gansu is on the rise in general, the units collected varies in each blood station. Therefore, further measures need to be taken from the aspects of publicity, recruitment, optimizing the collection process, improving the rate of double-dose collection, retention of regular blood donors and regional coordination to increase the collection units, narrow down the regional gap and ensure the balance between supply and demand.

During the replanting operation of a seedling tray, the end-effector needs to repeatedly grab the qualified plug seedlings in the supply tray and release them to the target tray for replanting, and in the process of grasping, the end-effector may cause some mechanical damage to the plug seedlings, thus affecting their quality. Therefore, in order to be able to adjust the position of the hand claw grasping point according to the morphological characteristics of the plug seedlings and select the optimal grasping point, this paper proposes research on the optimal grasping angle algorithm for plug seedlings based on machine vision. Firstly, a rotatable three-jaw end-effector is designed, which uses a three-jaw structure for grasping the burrowing seedlings. The three claws are driven with a telescopic cylinder to carry out clamping and relaxing actions. The rotation of the three claws is controlled with the stepper motor to adjust the optimal grasping position. Secondly, based on the pre-processing of an image of the hole tray seedling, the extraction of feature points in the region of interest, and the calculation of localization, the angle between the angular bisector of the cotyledon leaf blade of the hole tray seedling and the horizontal positive direction is solved. In this paper, two methods are designed to calculate the coordinates of feature points: one is the geometric method and the other is the center-of-mass method. Finally, the optimal grasping angle is calculated by analyzing the angle between the angular bisector of the cotyledon leaf blade and the horizontal positive direction of the cavity seedlings. According to the test, the average calculation error of the proposed algorithm is 3.12 degrees, and the average calculation time is 0.512 sec/sheet, which meet the requirements of the replanting operation.

Currently, the performance analysis of positioning algorithms and optimization of ground station deployment schemes are predominantly based on pure TOA or TDOA measurement information, and the relevant theoretical analysis is primarily the geometric analysis of optimal station deployment for fixed point targets, with few placement ranges and amount of station constraints. In practice, however, there are typically several measurements from TOA and TDOA stations, with a focus on positioning precision within a certain region or line trajectory, as well as the necessity for constraints on the ground station placement range. This paper proposes an efficient method for hybrid source localization using TOA and TDOA measurement information, establishes a mathematical model for hybrid source localization based on TOA and TDOA measurement information, derives and simulates the Gauss–Newton iterative localization algorithm with the least squares criterion, and performs a theoretical analysis of the least squares error and CRLB boundary to improve the accuracy of target localization in the aforementioned scenarios. Taking the average CRLB value of target line trajectory positioning error as the objective function, the ground station placement scheme of TOA- and TDOA-receiving sensors is optimized by utilizing a Genetic Algorithm with strong global optimization capability under the constraints of station placement range and station quantities, and a station placement geometry with better performance than typical station placement is obtained. Meanwhile, we summarize the general placement principles for TOA and TDOA hybrid source localization of target line trajectories.