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A two-stage low noise amplifier(LNA) with high gain and low power is proposed by analyzing the characteristics of GaAs pHEMT devices. A two-stage structure is used to increase the gain of the low noise amplifier, a shared current structure is presented to reduce the power consumption of the amplifie...

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Based on a technology of 0.15 μm GaAs high electron mobility transistor (pHEMT), a 19~21 GHz high linearity power amplifier MMIC was demonstrated in this paper. In the scenario of signal transmission with high peak-to average power ratio（PAPR）,the efficiency and linearity of power amplifier（PA）have...

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<sec><title>目的</title>评估1990至2021年“一带一路”共建国家40岁及以上人群下肢外周动脉疾病（LEPAD）的负担情况和不公平性，为疾病防治提供依据。</sec><sec><title>方法</title>利用2021年全球疾病负担数据库，分析155个“一带一路”共建国家40岁及以上人群的LEPAD年龄标化患病率、死亡率和伤残损失生命年（YLD）率，变化趋势使用估计年变化百分比（EAPC）衡量。采用不平等斜率指数和集中指数量化国家间LEPAD负担的绝对不公平和相对不公平。</se...

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A transcritical CO₂ heat-pump air-conditioning system has effective heating performance at low temperatures, and the variation of dynamic parameters during operation significantly affects the thermal comfort inside the passenger cabin. To study the comfort of the passenger com...

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ObjectiveA 2-UPS/RRR parallel mechanism was created for the rehabilitation of the ankle.MethodsThe mechanism’s three-dimensional model was created using SolidWorks software, and a moveable platform with an adjustable center of rotation was designed in accordance with various ankle rotation centers o...

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目的探讨喀什地区黑热病患者的流行病学和临床特征，以提高诊疗水平。方法对2013年1月至2023年12月喀什地区第一人民医院收治的71例黑热病患者的临床资料进行回顾性分析。结果71例黑热病患者中，0岁～5岁患者最多，占52.11%（37/71），男女比例为 0.92： 1，患者发病多在冬春季。临床特征主要表现为发热、乏力、食欲下降以及脾脏、肝脏增大。实验室检查主要为三系减少，血清白球比倒置、转氨酶升高、C反应蛋白及降钙素原升高。抗rK39抗体检测的阳性率为100%（23/23），骨髓镜检的阳性率为91.38%（53/58），肝组织病原宏基因组高通量测序（mNGS）检出杜氏利什曼原虫1例。常见的并...

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In order to investigate the effect of pore structure on the compression properties of porous titanium, the compression process of porous titanium was simulated by finite element method. The influence of different pore structure parameters such as porosity, pore size and pore shape on the compression...

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目的 探讨磁共振血管壁成像（vessel wall imaging，VWI）多序列与DSA评估大脑中动脉（middle cerebral artery，MCA）狭窄率的差异，明确最优序列的诊断价值。 方法 回顾性收集2022年3月1日—2023年8月31日在秦皇岛市第一医院接受VWI及DSA检查且证实MCA-M1段狭窄或闭塞的患者影像及临床资料。利用组内相关系数（intra-class correlation coefficient，ICC）评估VWI 5种序列[三维快速自旋回波序列扩展回波链采集技术（3D fast spin echo with an extended echo trai...

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At present, 3D model classification has been a research hotspot. Massive 3D models not only have diversity in each class, but also have similarities between classes, which seriously affect the classification accuracy of 3D models. We propose a 3D model classification method based on contrastive lear...

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3D model retrieval based on representative views was proposed. On the view representation of the 3D model, in order to fully represent the model and reduce redundant information, we firstly adopt Light Field Descriptor (LFD) to generate 2D views, and then use K-MEANS to get representative views from...

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In the 3D target detection technology based on point cloud, there are problems like high cost of point cloud calculation and large gap between target scales, which lead to low target detection efficiency. In response, this paper proposes a 3D object detection algorithm based on fusion sampling and g...

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ObjectiveTo solve the problem of accurate fruit segmentation in complex orchard environment. MethodA novel method for 3D reconstruction citrus fruit trees and fruit semantic segmentation of was proposed. First, the implicit 3D representation of the fruit tree was learned from multi-view images using...

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In order to solve the problem that the center position of the belt layer is offset during transmission, a 3D sensor based belt layer deviation correction algorithm is proposed in this paper. Firstly, the contour data collected by 3D sensor is preprocessed to make the data smoother. Secondly, in the...

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To improve the performance of two-dimensional direction-of-arrival (DOA) estimation of signals, a three-dimensional sparse array structure and its coupled tensor decomposition-based DOA estimation method was proposed. By utilizing the second-order statistics of the signals from these subarrays, a vi...

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