Your conditions: 刘念
  • Design of IMPix-N1, a silicon pixel detector readout chip for multi-dimensional measurements

    Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2024-04-19

    Abstract:  In order to meet the demand for elementary particle detection and analysis in high-energy physics experiments, modern pixel detector increasingly tends to pursue the performance requirements of low power consumption, high resolution, and high readout efficiency.This paper describes a silicon pixel detector digital-analogue hybrid readout chip named IMPix-N1. The pixel array consists of 16 rows × 16 columns of pixel units, each with an area of 100 μm × 100 μm, and the pixel array part is controlled by a 1-row × 8-column pixel unit as a superpixel, which has a common logic circuit. The chip has a pixel configuration mode and three pixel address readout modes of operation, which realises the measurement, storage and readout of the time, energy and position information of the hitting particles. The time-to-digital conversion circuit (TDC) can simultaneously measure and record the arrival time TOA and the over-threshold time TOT of the particles, with a time measurement accuracy of 5 ns. The IMPix-N1 is suitable for particle detection experiments requiring high temporal and spatial resolution as well as fast data acquisition capabilities.The chip as a whole is designed using the digital-on-top methodology in TSMC 180nm process. The design is simulated to verify the digital circuit of the pixel unit, the super pixel control circuit and the peripheral digital circuits, and the before and after simulation results are consistent and meet the design requirements.

  • 基于随机森林插值的中亚夏季极端高温变化特征

    Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2020-07-02 Cooperative journals: 《干旱区研究》

    Abstract:利用中亚地区65个气象站的逐日最高气温数据,结合ERA-Interim再分析资料以及经纬度、海拔数据,构建了随机森林插值模型,并验证了其可靠性。基于该模型补全了气象站缺失值,获得完整的站点逐日最高气温数据集TStation_f,并插值得到中亚1979—2016年空间分辨率为0.75°×0.75°的逐日最高气温格点数据集TRFIM_G。基于TRFIM_G进一步分析了中亚1979—2016年夏季极端高温指数时空变化特征。结果表明:中亚区域平均极端高温指数增速在0.22—0.30℃·(10a)-1,显著增温的区域主要分布在哈萨克斯坦的西部、土库曼斯坦大部、乌兹别克斯坦东南部等地区。基于TRFIM_G得到的夏季极端高温指数增速显著大于基于TStation_f得到的结果,这表明用站点观测数据对该地区夏季极端高温趋势的估计明显偏低。本研究得到的数据集可在一定程度上弥补使用站点观测数据片面刻画中亚地区极端高温变化的缺陷,有助于更确切地引导人们在应对极端天气气候事件时采取相应的减缓和适应措施。

  • 西沙群岛草海桐(Scaevola sericea)的抗逆生物学特性

    Subjects: Biology >> Botany submitted time 2018-03-27 Cooperative journals: 《广西植物》

    Abstract:热带珊瑚岛由于光照强、季节性干旱明显、土壤贫瘠、保水能力差而少有植物生长。草海桐(Scaevola sericea)是一种典型的热带滨海植物,是西沙群岛珊瑚岛植被中的主要建群种,在海岛和海岸带防风固沙及植被生态恢复等方面发挥重要作用。该文对西沙群岛自然环境下草海桐的形态解剖学特征、抗氧化能力、抗逆性物质含量及营养元素含量等进行了研究,结果发现:草海桐具有阳生性植物特征,叶片及上表皮厚、气孔密度小、导管直径及水力导管直径大,有利于其适应珊瑚岛干旱环境;其体内的超氧化物歧化酶和过氧化氢酶活性相较于其他受胁迫植物高,脱落酸含量也较高,表明草海桐对珊瑚岛环境具有较强的适应性及抗逆性;其根际土壤养分含量偏低,但植物体内营养元素含量较高,表明草海桐对土壤养分的利用效率高。研究结果表明,草海桐能够很好地适应干旱、贫瘠的珊瑚砂环境,具有较强的抗逆及适应能力,这为草海桐的引种驯化及开发利用提供了重要基础资料。

  • 饲粮营养水平对黄羽肉鸡生长性能、肉品质和性成熟的影响

    Subjects: Biology >> Zoology submitted time 2017-10-10 Cooperative journals: 《动物营养学报》

    Abstract:本试验旨在研究饲粮营养水平对黄羽肉鸡生长性能、肉品质和性成熟的影响。采用单因子完全随机设计,将432只1日龄商品代北京油鸡随机分配到高、中和低3种营养水平组,每组4个重复,每个重复36只鸡,自由采食、饮水。饲粮按中速黄羽肉鸡的饲养标准分为3个阶段(1~5周、6~9周和10~13周),每个阶段在保持蛋白质与能量比值不变的情况下分别设置高、中和低3种营养水平。结果表明,1~5周,低营养水平组肉鸡的平均日采食量和平均日增重极显著低于中、高营养水平组(P0.05)。高营养水平组母鸡鸡冠重和鸡冠长度极显著高于中、低营养水平组(P0.05)。由此可见,对于中速型黄羽肉鸡,中营养水平的饲粮能获得较好的生长性能,高营养水平的饲粮能促进母鸡性成熟。