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Search Results: 1 - 10 of 305198 matches for " 王州 "
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直升机齿轮箱故障诊断方法
A New Method for Fault Diagnosis of Helicopter Gearbox

李耀华,
- , 2018,
Abstract: 为有效诊断直升机齿轮箱故障,研究建立了基于直升机齿轮箱振动信号的小波包熵ABC-BP神经网络故障诊断模型。模型以小波波包分析与信息熵分析方法为基础,提取齿轮箱振动信号的小波包熵作为神经网络的特征输入向量,引入人工蜂群优化BP神经网络,将BP神经网络的误差函数作为人工蜂群的适应度,选择适应度最优的个体参数作为神经网络的权值和阈值,不仅降低模型输入维度,还提高了诊断精度。最后基于实验数据进行了验证,结果表明该诊断模型具有较好的故障诊断效果。
To improve the fault diagnosis efficiency of helicopter gearbox, the information entropy and ABC-BP neural network are adopted in this paper. Combining wavelet packet and information entropy, the wavelet packet entropy of vibration signal of gearbox is extracted as the characteristic input vector of neural network, then the BP neural network is used for pattern recognition and fault classification of the characteristic parameters of gearbox, and artificial bee colony (ABC) is introduced in the optimization of BP neural network. The error function of BP neural network as the artificial bee colony fitness, individual parameters of optimal fitness degree are choose as the weights and thresholds of neural network. This method not only reduces the model input dimension, but also improves the diagnostic accuracy. Finally, the experimental results show that the diagnosis model has good effect
基于13项形态学指标的远东黑蜂形态变异分析
Morphometric Analysis of Far East Blank Bee Based on 13 Indexes of Morphometry
 [PDF]

, 薛运波, 张发, 金水华, 李兴安
Hans Journal of Agricultural Sciences (HJAS) , 2014, DOI: 10.12677/HJAS.2014.45014
Abstract:
为了积累远东黑蜂的形态学数据,和以此数据为依据表征远东黑蜂,本研究首先通过显微图像分析方法分别测定了10群远东黑蜂样本和10群欧洲黑蜂样本各自的13项尺度类形态学指标;其次,通过F-分析比较了远东黑蜂样本测定值均数与欧洲黑蜂样本测定值均数的离散程度,通过t-检验比较了远东黑蜂样本测定值均数与欧洲黑蜂样本测定值均数的差异性。远东黑蜂样本的吻长度、第四蜡镜宽度、第四蜡镜面积测定值均数,都明显地小于欧洲黑蜂样本的相应测定值均数(P < 0.05);相反,它们之间的第三背板宽度、第四背板长度、第四背板宽度、第四蜡镜长度、前翅长度、前翅宽度、前翅面积、前翅肘脉指数、后腿跗节长度以及后腿跗节宽度测定值均数,都没有差异(P > 0.05)。这提示,相对于欧洲黑蜂,远东黑蜂具有明显的形态学体征:短的吻长度,短的第四蜡镜宽度和小的第四蜡镜面积。
A Microscopic image analysis was conducted to collect a set of morphometric data for characterizing morphological features of Far East Blank Bee. First of all, we measured 13 indexes of morphometry of 10 colonies of both Far East Blank Bee and Apis mellifera mellifera, respectively. Then we compared discreteness of means of measured values between them, and compared difference of the means between them. Compared to samples of colonies of Apis mellifera mellifera in the measurements of proboscis length, width and surface area of wax mirror IV, samples of colonies of Far East Blank Bee are showed with shorter proboscis, shorter wax mirror IV, and smaller surface area of wax mirror IV (P < 0.05, respectively). On the contrary, compared to samples of the former with the measurements of the others, samples of the latter are not showed with significant differ-ence of measurements, including width of tergum III, both length and width of tergum IV, length of wax mirror IV, length, width, surface area, cubital index of forewing, and both length and width of metabasitarsus hindleg (P > 0.05, respectively). The present analysis could distinguish the mor-phometric difference between the samples of colonies of both Far East Blank Bee and Apis mellifera mellifera.
工业过程的一类时变模型的建立与控制方法研究
李宛, 京春
自动化学报 , 2006,
Abstract: ?电渣重熔过程是典型的时变系统。电渣重熔炉冶炼质量高的原因在于过程熔速控制均匀。本文通过现场运行数据采集与仿真分析,详细解析了电渣重熔炉过程中诸多参数之间的相互关系,提出并实现了电渣重熔炉的时变系统模型,并成功的应用于邢台机械轧辊集团铸钢分厂美国康萨克15吨电渣炉技改项目上。通过现场6个月的实际运行,控制效果良好,部分参数甚至优于原控制系统。
NO参与Spd诱导白三叶抗氧化酶活性及其基因表达
晓娟,,彭燕
草业学报 , 2015, DOI: 10.11686/cyxb20150417
Abstract: 以‘拉丁诺’白三叶为试材,采用药理学实验,探讨一氧化氮(NO)信号在外源亚精胺(Spd)诱导抗氧化酶活性及其基因表达中的作用。研究结果显示,20μmol/L的外源Spd可显著提高白三叶叶片硝酸还原酶(NR)和一氧化氮合酶(NOS)活性,诱导白三叶离体叶片NO积累,并且具有时间效应,在处理第2h达到最大值;50μmol/LNO清除剂牛血红蛋白(Hb)、5mmol/L硝酸还原酶(NR)抑制剂偏钒酸钠(NaVO3)以及200μmol/L一氧化氮合酶(NOS)抑制剂NG-硝基-L-精氨酸甲酯盐酸盐(L-NAME)处理均可不同程度地逆转Spd诱导的NO含量的升高。外源Spd亦可提高白三叶叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和抗坏血酸过氧化物酶(APX)的活性及其基因的相对表达量,而Hb、NaVO3和L-NAME不同程度地抑制了Spd诱导的SOD、POD、CAT、APX酶活性及其基因表达。以上结果表明:Spd可能通过激活硝酸还原酶和一氧化氮合酶途径诱导产生NO,且NO信号参与了Spd调控白三叶叶片抗氧化酶活性及其基因表达。
火焰模拟方法的研究综述
,顾耀林
中国图象图形学报 , 2007, DOI: 10.11834/jig.20071103
Abstract: 火焰等无规则物体的模拟近年来成为计算机动画领域中的一个研究热点,回顾了该领域中火焰模拟的各种模型的发展情况,总结了该研究方向所采用的各类方法,并结合各种模型的特点分门别类地详细展开。其方法总体上可以分为粒子系统方法、数学物理方法和纹理技术方法,讨论了各自方法的优缺点、适用范围和效果特征;展望了未来发展的3个重点:火焰细节、控制机制和模拟速度;并对这个方向的研究前景进行了必要的探讨。
中国粉虱科二新纪录种记述(半翅目:粉虱科)
吉锐,杜予
昆虫分类学报 , 2015,
Abstract:
三维涡流计算中最少变量数边界积分方程的一个注记
方蜀,泽毅
电子学报 , 2002,
Abstract: 本文回顾了求解三维电磁场涡流问题的数值计算方法,其中最少变量数边界积分方程法(BoundaryIntegralEquationsofMinimumOrderMethod)具有很多优点.但提出该方法的论文以及后续论文中的边界积分方程中存在一些错误,本文给出了边界积分方程的极限推导过程,改正了这些错误.
‘杨格尔’与‘京秀’葡萄胚珠发育过程中活性氧代谢的比较研究
张朝红,跃进,西平,杨亚
园艺学报 , 2007,
Abstract: 以盛花后不同时期的无核葡萄品种杨格尔和有核葡萄品种京秀的胚珠为材料,测定胚珠中超氧阴离子和过氧化氢(h2o2)含量及活性氧清除酶活性的变化。结果表明:在两品种胚珠发育过程中均呈一直上升的趋势,在胚珠发育的中后期无核品种扬格尔产生速率明显大于有核品种京秀;胚珠中h2o2含量表现先升后降再升的趋势,但再升时无核品种扬格尔显著大于有核品种京秀;胚珠内活性氧清除酶超氧化物歧化酶(sod)、过氧化氢酶(cat)、抗坏血酸过氧化物酶(asa-pod)及无核品种扬格尔的过氧化物酶(pod)表现先升后降的趋势,无核品种扬格尔的酶活性在胚珠败育后明显下降,有核品种京秀仍在较高的水平,且有核品种的pod活性先快速上升后一直保持缓慢上升的趋势。胚珠内活性氧类物质及活性氧清除酶类的变化趋势与无核葡萄杨格尔幼胚败育有一定相关。
50例危重新生儿T细胞亚群及免疫抗体的检测
成秀,,谢琴,莉佳
第三军医大学学报 , 2007,
Abstract:
西藏野生宽叶韭的繁育更新特性研究
Reproductive development characteristics of Tibetan wild Allium hookeri Thwaites

忠红,,关志华,
- , 2017,
Abstract: 【目的】明确西藏野生宽叶韭的繁育更新特性。【方法】通过实地观察,分析宽叶韭的无性繁殖及开花结实特性,测定宽叶韭种子的形态特征、吸水与发芽规律;以温度(4,10,15,17.5,20,22.5,25,30,35,40 ℃)和贮藏时间(14个月和2个月)为考察因素,研究其对宽叶韭种子发芽率的影响。【结果】(1)西藏野生宽叶韭为冬季倒苗型,可分蘖无性繁殖和种子有性繁殖;(2)开花结实期为8-10月份,平均每花序有小花56.33个,开放授粉下小花结实率98.72%,每小花结籽1~4粒不等,结1粒种子的小花占83.48%,结2粒种子的占15.42%,结3~4粒种子的极少;套袋自交下小花结实率18.35%,每小花有种子1~5粒不等,结1粒种子的小花占73.17%,结2粒种子的占23.78%,结3~5粒种子的极少;(3)种子椭球形,横径1.93 mm,纵径3.41 mm,百粒质量0.987 7 g;(4)在20 ℃恒温下浸种以4 h为宜,最长不超过30 h,否则种子内含物大量外渗,可能影响种子发芽;(5)种子常温下贮藏1年以后发芽率急剧下降,短期贮藏(2个月)对发芽率无影响,发芽适温为15~25 ℃,长期置于10 ℃下也能达到很好的发芽效果。【结论】西藏野生宽叶韭具有性和无性2种繁殖方式,开放授粉和套袋自交均能结籽,种子发芽适温为15~25 ℃。
【Objective】This paper explored the reproductive development and seed characteristics of Tibetan wild Allium hookeri Thwaites.【Method】Through field observation,asexual reproduction,flowering characteristics,morphological characteristics,water absorption and seed germination of A.hookeri were examined.Effects of temperature (4,10,15,17.5,20,22.5,25,30,35,and 40 ℃) and storage time (14 months and 2 months) on germination rate of A.hookeri seeds were also investigated.【Result】(1) Tibetan wild A.hookeri withered during the winter,and reproduced asexually by tillering and sexual reproduction through seeds.(2) The flowering and fruiting period was from August to October.There were 56.33 flowers per inflorescence with setting rate of 98.72% in open pollination status.There were 1 to 4 seeds per flower,83.48% with 1 seed,15.42% with 2 seeds,and very small amount with 3-4 seeds.The setting percentage was 18.35% with bagged self-pollination method.There were 1 to 5 seeds per flower,73.17% with 1 seed,23.78% with 2 seeds,and very small amount with 3-5 seeds.(3) The seeds were oval,and the transverse and longitudinal diameters were 1.93 mm and 3.41 mm,respectively.The weight per 100 seeds was 0.987 7 g.(4) Optimum duration for seed presoaking at 20 ℃ was 4 hours.The maximum time for seed presoaking should not exceed 30 hours,otherwise the hydroquinone extracts would infiltrate and seed germination was affected.(5) Germination rate declined sharply after 1 year in storage at normal temperature,while short-term storage for no more than 2 months had no significant effect.The optimum germination temperature was 15-25 ℃,and storage at 10 ℃ for a long time also had highly positive effect on germination.【Conclusion】Tibetan wild A.hookeri can propagate both sexually and asexually.Both cross pollination and selfing through bagging can produce seeds.Optimum temperature for germination is 15 to 25 ℃.
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