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1.
利用收集到的降水雨滴谱资料与多普勒雷达的观测资料,将Parsivel激光降水粒子谱仪计算的回波强度与雷达观测的回波强度作以比较,结果表明:两者具有较好的一致性,雷达观测到的回波强度有低估的现象,并且降水强度越强,回波强度越大,雷达低估的现象越为明显。经过回波修正后,用统计的Z-I关系式估算的降水量与Parsivel测得的降水量更为接近,可以提高雷达定量估算降水的准确性。  相似文献   

2.
利用常规天气图资料、地面观测资料、南昌多普勒天气雷达资料和闪电定位资料,对2004—2008年新余雷电过程的气候概况、天气影响系统和雷达回波产品等进行研究分析,结果表明:(1)新余雷电具有明显月分布特征,主要集中在7—8月;雷电的日变化主要集中在13:00—20:00,17:00出现次数最多,而夜间到上午则很少出现。(2)有利于新余发生雷电的天气影响系统有:地面冷锋和西南倒槽、高空低槽和切变线、低空急流和副热带高压。(3)南昌站单站有利于产生雷电天气的物理量参数有10个,满足其中5个以上就有可能出现雷电天气。(4)雷电天气的雷达回波产品主要有:回波顶高度ET,基本反射率CR,垂直积分液态水含量VIL。(5)雷电天气预警信号的发布标准有3种:一般雷电发布雷电黄色预警信号;较强雷电发布雷电橙色预警信号;强雷电发布雷电红色预警信号。  相似文献   

3.
2008-06-25安阳出现了一次强对流天气,濮阳新一代天气雷达及时捕捉到了这次天气的全过程。通过强对流回波的组成、移动、变化等分析了这次强对流系统的发展演变过程及其雷达回波特征,重点讨论了多普勒雷达产品基本特征,并采用多个反射率产品、剖面产品、速度产品等综合分析了该风暴的三维结构。  相似文献   

4.
5.
文章利用地面常规观测资料、ECMWF ERA5再分析资料、三维闪电定位资料及雷达资料对乌兰察布市2021-07-05出现的一次强对流天气进行了详细的分析和研究。文章主要分析了高低空环流形势、地面形势场和物理量场的演变特征,以及强对流天气发生时,雷达回波特征和闪电特征,为本地强对流天气的预报提供有利的依据。  相似文献   

6.
文章利用NCEP全球再分析资料和常规观测资料对2016-03-19漳州市的一次强冰雹天气过程进行分析,得出此次冰雹过程是在有利大尺度环流背景下的一次中尺度对流天气过程。当径向速度出现中气旋特征、垂直累积液态水含量出现跃增现象时,预示着即将出现冰雹天气。研究成果对冰雹的短时预报有着较好的指示意义,可更好地提供冰雹的预警预报服务。  相似文献   

7.
多普勒天气雷达径向干扰回波的识别与消除   总被引:1,自引:0,他引:1  
多普勒天气雷达在探测气象目标物同时,除了目标物的回波外,一些非目标物的同频电磁波有时也会被散射进入雷达接收系统形成杂波,被称为径向干扰回波。径向干扰回波是污染雷达回波资料的重要因素之一,严重影响雷达资料的定量应用。文章介绍了如何对径向干扰回波进行识别,并给出3种订正方法,即插值法、中值滤波法和多功能插值法,并对这3种方法进行了对比,分析了各种订正方法的优点和局限。实例分析表明通过以上对基数据的处理方法能够对径向干扰回波进行有效的识别和订正,从而获取更准确的雷达基产品及后期导出的二次雷达产品。  相似文献   

8.
多普勒天气雷达回波数据质量检测及控制方法   总被引:1,自引:0,他引:1  
本文提出了一种基于天气雷达回波强度和速度数据的质量检测方法。通过采集天气雷达按统一的参数进行标定后的晴空标准地物回波强度作为模版,与实时采集的回波强度进行比较和误差分析,以及通过移相来自动检测速度数据理论值和实测值的误差大小,对回波强度数据和速度数据质量进行检测和校正,以此来实现对天气雷达回波数据的质量控制。  相似文献   

9.
根据长沙CINRAD WSR-98D天气雷达在2006-04-11获取的雷达资料,利用新一代多普勒天气雷达的部分基本产品和二次产品对飑线过程进行分析,总结了一些能有效识别飑线的特征.  相似文献   

10.
当前,新一代天气雷达得到了广泛应用,可以满足社会生产生活的基本要求。文章分析了雷达回波异常产生的原因及解决措施,希望为气象观测措施制定,提供有价值的建议。  相似文献   

11.
针对在大吨位沉船打捞中的升沉补偿技术,提出了一种基于韩国“世越”号沉船打捞的双驳抬吊半主动升沉补偿打捞系统,模拟了双驳共66组带有半主动升沉补偿器(SAHC)系统在类似历史海况下对沉船位姿和缆绳拉力的补偿过程。建立了半主动升沉补偿液压系统、缆绳系统与沉船运动的数学模型,以及负载-缆绳-补偿系统的耦合系统,推导了驳船各吊点的升沉补偿量。通过MATLAB/Simulink仿真系统的负载特性、缆绳拉力和沉船位姿变化。证明半主动升沉补偿对削弱负载位移和减轻缆绳拉力同时有显著作用,为实际沉船打捞中应用半主动升沉补偿技术提供了理论依据和技术参考。  相似文献   

12.
Awareness on the mechanical properties of agricultural products is necessary in order to estimate and predict the deformation of viscoelastic materials under external loads for system design, transport, processing and packaging. The aim of this study was to evaluate three theories (i.e. Hooke, Hertz and Boussinesq) on the apparent modulus of elasticity of some apple varieties i.e. Golden Delicious, Red Delicious and Granny Smith. The theoretical results were analyzed in a factorial experiment with completely randomized design with 9 treatments and 15 replicates. The results showed the practical usability of Hertz’s theory with better prediction accuracy whilst the Boussinesq’s theory showed a significant difference of predicted modulus of elasticity compared to other theories and the values reported in some publications. Although, the Hook’s theory enables the identification of a bio-yield point on its force–deformation curve, but Hertz’s theory was recommended as the most appropriate method due to easiness of working on a cylindrical sample of apple and the closer agreement with reality. Based on the results of this study, Golden Delicious and Granny Smith varieties had the lowest and the highest modulus of elasticity as 2.211 MPa and 3.431 MPa, respectively. This difference shows the firmness of apple varieties and different tissue responses to external loads and forces accordingly.  相似文献   

13.
基于特型选尺法求解二素数副的解答图原理,将其等差刻度尺改进为非等差刻度尺,可使相同长度的刻度尺扩大解答范围,或使相同解答范围时缩短其刻度尺的长度,增强了求解哥古猜想解答的简便性,适应了求解者的所需用况。  相似文献   

14.
基于参考文献[1]及[2]的特型选尺法求解二素数副的解答图原理,介绍了其解答图的新结构形式,拓展了解答图的应用范围,实现了一个解答图求解五种或九种解答值的功效,提高了解答图的利用程度,适应了求解者的所需用况。  相似文献   

15.
李昭  冯蕾 《现代仪器》2013,(1):25-29
随着超声技术的不断发展,超声在桥本甲状腺炎的诊断中发挥出越来越重要的作用。利用超声检查不仅可直观提供病灶形态信息、血流分布信息、组织硬度信息,同时还可以引导穿刺活检,做出定性诊断,为早期鉴别甲状腺结节良恶性提供帮助。本文就桥本甲状腺炎的超声诊断研究进展予以综述。  相似文献   

16.
基于人们视觉生理变化规律,从机床的形态和色彩演变可以看出,视觉生理对产品的形态和色彩感到满意后,会出现“看腻”的现象,逐渐失去了平衡,产生要求新的内容补充以取得平衡的欲望.但新的平衡要具有新的内容,而不是旧平衡内容的简单重复.  相似文献   

17.
为了提高汽车在雨天和雪天行驶时驾驶员的能见度,专门设置了风窗玻璃刮水器系统。本文主要简述风窗玻璃刮水系统及其设计方法。  相似文献   

18.

The studied hypothesis is that the herbicide glyphosate (GLY) can affect the oxidative balance in the hydrophobic intracellular medium in non-target Chlorella vulgaris cells. Analytical GLY and RoundUp (RUP) supplementation, affected the growth profile. A significant 42% decrease in the cellular biomass in stationary (St) phase was observed in cultures supplemented with either 5 µM of GLY or RUP, as compared to control cultures. The treatment with 0.3 µM of GLY generated non-significant effects on the oxidation rate of 2’, 7’ dichlorofluorescein diacetate (DCFH-DA), neither in exponential (Exp) nor in St phase of development, as compared to control cultures. However, the treatment with either 5 µM GLY or 0.3 and 5 µM RUP lead to a significant decrease in the DCFH-DA oxidation rate, as compared to control cultures. The lipid radical (LR) generation rate, detected by Paramagnetic Resonance Spectroscopy (EPR), was significantly increased in the presence of RUP, in Lag and Exp phase of growth. The non-enzymatic antioxidants, α-Tocopherol (α-T) and β-Carotene (β-C), are aimed to protect membranes against the damage produced by the radical reactions. The content of β-C was not significantly affected, as compared to control cultures, by any of the treatments, in both growth phases of cellular development. The content of α-T was significantly decreased by the supplementation with either 0.3 or 5 µM of RUP or 5 µM GLY. The LR/α-T ratio, used as indicator of the oxidative balance in the hydrophobic cellular media, was significantly different between samples obtained from control and RUP-exposed microalgae in both, Exp and St phase of development, with either 0.3 or 5 μM RUP. The data presented here showed evidence that suggested that oxidative balance in the hydrophobic environment was affected by either GLY or RUP.

  相似文献   

19.
基于近似极小值原理的插电式混合动力汽车实时控制策略   总被引:2,自引:0,他引:2  
将发动机的瞬时油耗拟合成由一次函数和二次函数组成的分段函数形式,将电池瞬时等效油耗拟合成由两个二次函数组成的分段函数形式,在此基础上,通过对Hamilton函数的分析,提出通过简化最优控制变量搜索空间来缩短寻优时间的近似极小值原理实时控制策略,并将该策略的等效油耗优化效果和计算时间分别与基于规则的CD-CS模式控制策略和基于极小值原理的最优控制策略进行对比。结果表明,上述提出的实时控制策略在等效油耗优化效果方面接近基于极小值原理的最优控制策略,而明显优于基于规则的CD-CS模式控制策略,在计算时间方面接近基于规则的CD-CS模式控制策略,而明显短于基于极小值原理的最优控制策略。  相似文献   

20.
Background: Huang-Pu-Tong-Qiao formula (HPTQ), a traditional Chinese herbal formula, has a variety of pharmacological effects. It has been used to treat Alzheimer’s disease (AD) for decades. This study aimed to screen differentially expressed proteins in the hippocampus of AD model rats treated with HPTQ. Proteomic studies of the effects of HPTQ on AD are key to understanding the therapeutic mechanisms of HPTQ and identifying potential therapeutic targets. Methods: We hence used the isobaric tags for relative and absolute quantification (ITRAQ) approach to investigate the differentially expressed proteins in the hippocampus of AD model rats before and after HPTQ administration and to identify the potential therapeutic target proteins of HPTQ. In this study, the learning and memory abilities of AD rats were examined by the Morris water maze test. After HPTQ administration, the differentially expressed proteins in the hippocampus of AD rats were quantified and analyzed in silico. Furthermore, western blotting was used to verify the expression of related proteins. Results: The Morris water maze results showed that HPTQ could improve the learning and memory ability of AD model rats. The proteomics analysis results showed that 57 proteins were differentially expressed, of which 35 were up-regulated and 22 were down-regulated. Bioinformatics analysis indicated that proteins with altered expression after HPTQ treatment were involved in several biological processes that have the potential to exert neuroprotective effects. These included promoting the translation of ribosomes, improving the deposition of amyloid-beta (Aβ), regulating autophagy, regulating neuronal synaptic function and plasticity, and alleviating oxidative stress. Conclusion: In conclusion, we identified several potential therapeutic target proteins and related mechanistic pathways of HPTQ in the treatment of AD, laying the foundation for further investigation of the therapeutic effects of HPTQ.  相似文献   

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