特征模型融合研究

特征模型为特定领域内软件需求的组织和复用提供了有效的手段.为了构建特征模型,领域分析人员要对领域内尽可能多的应用软件进行系统化分析,识别共性和变化性需求,并根据需求之间的依赖关系抽象和组织需求.随着软件系统复杂性的不断提高,特征模型的规模有日益增加的趋势,特征模型的构建也随之成为了一件十分困难的工作,亟需自动化方法的支持.一种可行的方式是将领域内已有的多个特征模型自动融合为一个较大规模的特征模型,并由人工对融合结果进行微调.现有研究提出了6种特征模型的自动化融合方法.文中在现有研究的基础上,提出了一个特征模型融合的概念框架,并根据此框架对6种方法进行了比较和分析.文中还进一步指出了现有研究亟需解决的3个问题,并针对每个问题提出了可能的研究思路和设想.     

Spectral Characteristics and Its Regularity of Rare Earth Ions in Inorganic Microporous Material Ⅲ．Spectral Characteristics of Ce~（3＋） in Zeolite Hosts

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Screener3D:a gaseous time projection chamber for ultra-low radioactive material screening

In experiments searching for rare signals,back-ground events from the detector itself are some of the major factors limiting search sensitivity.Screening for ultra-low radioactive detector materials is becoming ever more essential.We propose to develop a gaseous time projection chamber(TPC)with a Micromegas readout for radio screening.The TPC records three-dimensional tra-jectories of charged particles emitted from a flat sample placed in the active volume of the detector.The detector can distinguish the origin of an event and identify the particle types with information from trajectories,which significantly increases the screening sensitivity.For a particles from the sample surface,we observe that our proposed detector can reach a sensitivity higher than 100 p Bq m-2 within two days.     

Lagrage插值——极差法计算不同食物氨基酸互补的相互比例

为了提高食物的蛋白质生物价,可以采用两种或两种以上食品混合食用的方法,使限制氨基酸互相弥补,只要混合食物的氨基酸评分高于各单个食品,一般可以认为混合食物的生物价高于各单个食品。     

多源遥感数据与水文过程模型的土壤水分同化方法研究

提出一种基于集合卡尔曼滤波的一维数据同化系统,对不同深度土壤层的水分含量进行同化,该系统的模型算子为分布式水文模型,观测算子是积分方程模型和条件温度指数模型.于2008年6月1日至7月2日在黑河流域进行了同化实验,结果表明,集合卡尔曼滤波能较好地处理强非线性问题,与单独DHSVM模型模拟土壤水分含量相比,同化的表层和根层土壤水分含量精度有明显提高,其中盈科站表层的均方根误差和平均误差分别减小了0.021 7和0.032 9,根层的均方根误差和平均误差分别减小了0.019 3和0.025;临泽站的精度也有明显提高,表明多源遥感数据的同化在地表土壤水分含量的估计中具有较大的潜力.     

高压液相色谱-氢化物发生-原子荧光光谱(HPLC-HG-AFS)联用技术检测水产品中硒的赋存形态

目的 采用高压液相色谱-氢化物发生-原子荧光光谱联用技术(HPLC-HG-AFS)对水产品中硒的赋存形态检测进行研究。方法 通过实验优化流动相、提取剂、提取时间及其仪器条件, 建立HPLC-HG-AFS联用技术检测水产品中硒形态的分析方法。用去离子水在70 ℃水浴下超声提取1 h, 流动相为pH 6.0的40 mmol/L(NH4)2HPO4溶液, 阴离子交换柱分离, HG-AFS检测。结果 样品加标量在0.10、1.00 mg/kg时的回收率均在86.6%以上, 相对标准偏差均小于5%。结论 本研究证明使用该方法测定水产品中的硒形态较为准确、可靠, 为科学评价水产品质量、进一步细化富硒水产品的判定标准和鉴别其真伪提供技术手段, 为科学有效地开展其风险评估提供技术支撑和数据支持。     

Beam-Switching Antenna Based on Plane Dipole Structure

A novel method for designing a beam-switching antenna with the plane dipole is presented. The antenna is composed of double dipoles placed at the center of an active square structure that is divided in four equal sectors by metallic sheets. Metallic patches at the outside of the structure are used to enhance the radiation performance of the antenna. In each step, the diodes in one sector are on, whereas other diodes are off. The sector with off-state diodes defines the direction of the radiation pattern. An antenna model is designed on the substrate of FR4. The proposed antenna operates from 4.8 GHz to 5.5 GHz with gain of 6.3 dBi and F/B (front to back ratio) of 13.2 dBi when the operating frequency is 5.2 GHz. The antenna radiation pattern can be swept in the entire azimuth plane in four steps with a 3 dB beamwidth of 90. The results reveal that the antenna could be used in the base station of the wireless communication systems.     

基于16S rRNA基因的不同基原、不同产地甘草微生物群落特征分析

目的 探究4批不同基原、不同产地的甘草微生物群落信息。方法 参照《中国药典》2020年版四部,对甘草药材中的需氧菌总数、霉菌和酵母菌总数、耐热菌总数以及控制菌进行检查,并对致病菌平板上的菌落进行革兰染色,同时进行甘草药材的16S rRNA基因测序及数据分析。结果 甘草药材中的需氧菌总数、霉菌和酵母菌总数、耐热菌总数对数值分别为4.15～4.95、2.40～4.85、1.67～3.15;经热处理(100℃、30 min)后发现其需氧菌总数对数值的下降百分比分别为100.00%、24.10%、40.20%、66.26%;各甘草中耐胆盐革兰阴性菌可能总数较高,但均未检测到大肠埃希菌和沙门菌。16S rRNA基因测序共获得19 phylum、40 class、68 order、137 family、236 genus,其中GC-2获得最多的phylum (18)、class (36)、order (58), GC-1和GC-3获得最多的family (121), GC-1获得最多的genus (162)。多样性分析结果表明,甘草药材中污染微生物主要分布于3个门、3个属,不同基原、不同产地的甘草...     

京西稻米中脂肪酸构成与评价

目的 评定京西稻米中脂肪酸的构成,丰富北京市特色食物成分数据库.方法 依据GB5009.168—2016《食品安全国家标准食品中脂肪酸的测定》中的气相色谱法测定20批次北京市不同区域京西稻米中脂肪酸的含量,并评定其脂肪酸的构成.结果 京西稻米中脂肪酸种类多达14种,总脂肪酸含量为0.514～1.327 g/100 g....     

Ginsenoside 20(R)-Rg3 stimulates glucose uptake in C2C12 myotubes via CaMKK-AMPK pathways

Based upon preliminary study showing stimulation of glucose uptake by 20(R)-Rg₃, a stereoisomer of 20(S)-Rg₃ ginsenoside found in red ginseng, we investigated the action mechanism of 20(R)-Rg₃ in differentiated C2C12 myotubes. It was found that 20(R)-Rg₃ stimulated translocation of glucose transporter 4 (GLUT4) and glucose uptake in a concentration-dependent manner. In addition, 20(R)-Rg₃ phosphorylated AMP-activated protein kinase (AMPK) and Ca²⁺/Calmodulin-dependent protein kinase kinase (CaMKK) in time- and concentration-dependent manners. In the meantime, 20(R)-Rg₃-induced glucose uptake and translocation of GLUT4 were attenuated in the presence of compound C (an AMPK inhibitor) or STO-609 (a CaMKK inhibitor). Taken together, this study is the first to demonstrate that 20(R)-Rg₃ stimulated the glucose uptake via translocation of GLUT4 and this effect was seemed to be mediated by CaMKK-AMPK pathways in C2C12 myotubes.