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Search Results: 1 - 10 of 274657 matches for " 张龙 "
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典型地质模型2D与3D重力正演模拟对比研究
Comparative Study on 2D and 3D Gravity Forward Modeling of Typical Geological Model
 [PDF]


Advances in Geosciences (AG) , 2015, DOI: 10.12677/AG.2015.54029
Abstract: 本文典型地质模型三维重力正演模拟研究是在二维重力正演方法总结的基础上,对地质模型作三维重力正演探究。其中所建的地质模型以球体为主。分别导出了二维与三维重力布格异常,重力异常各阶导数公式。在MATLAB环境下实现了模型的二维与三维重力异常曲线图。结合二维重力正演的分析方法,本文对模型进行了三维重力正演分析,对比讨论了三维重力正演与二维重力正演的优缺点,得到了二维重力正演只能反应地质体垂直切片的重力信息,三维重力正演可以就反映出地质体的整个重力信息,小的局部地质体可以通过高阶导数分析得出其规模形状的结论。
The study of three-dimensional gravity forward of typical geological model was based on the two- dimensional gravity forward method. The sphere is presented as the main geological model, which derives two-dimensional and three-dimensional gravitational Bouguer anomaly, the gravitational anomaly formula of every derivative respectively. The two-dimensional and three-dimensional gravity anomaly curve was achieved in the MATLAB environment. Combining with the analytical method of two-dimensional gravity forward modeling, this paper conducted a three-dimensional gravity forward modeling analysis, as well as compared and discussed the advantages and disad-vantages of two-dimensional gravity forward and three-dimensional gravity forward, and then got the results that two-dimensional gravity forward can only reflect gravity information of geological vertical slice, while three-dimensional gravity forward can reflect gravity information of the whole geological body. Small local geological body can obtain its size and shape through analyzing high- order derivative.
李代数Der(Cq)∝Cq 的导子代数
The Derivation Algebra of Lie Algebra Der(Cq)∝Cq
 [PDF]

, 申冉
Pure Mathematics (PM) , 2015, DOI: 10.12677/PM.2015.51001
Abstract:
本文给出了李代数Der(Cq)∝Cq的导子代数结构。证明了其有一维外导子。
In this paper, the derivation algebra of Lie algebra we give is Der(Cq)∝Cq. We prove its outer derivation is one dimension.
基于BP神经网络的高阶FIR多阻带滤波器优化设计
Study on Optimal Design of High-Order FIR Filter with Multi-Band Stop Based on BP Neural Network
 [PDF]

, 李德超, 玉环
Advances in Energy and Power Engineering (AEPE) , 2014, DOI: 10.12677/AEPE.2014.21001
Abstract:
本文对传统BP神经网络算法加以改进,以余弦基函数作神经元的输出函数,克服了传统BP神经网络收数速度慢、学习步长低的致命缺陷。通过对线性相位FIR滤波器幅频特性和搭建余弦基神经网络模型对二者进行研究,并通过仿真研究得出该算法在高阶多阻带滤波器设计中的具有很强的优越性。
This paper improves the traditional neural network and conquers its disadvantages of the slow convergence speed and the low learning efficiency with cosine basis functions as output functions of neural network unit. It studies on the amplitude-frequency characteristic of the FIR filters with linear phase by putting up models of neural network based on the cosine basis functions, and drawing the conclusion of relationship between them. The simulation results show that the algorithm has advantages over the design field of high-order FIR filter with multi-band stop.
国内外蝗害治理技术现状与展望

应用昆虫学报 , 2011,
Abstract: 本文首先概述了国内外蝗虫发生与为害的态势,总结了现阶段我国蝗虫发生与为害的主要特点:即农田飞蝗暴发频繁而且严重,草原土蝗的发生时常造成严重的经济损失,而且侵入城市干扰市民生活,我国与周边国家之间蝗虫过境迁移频繁,使用化学农药污染环境和农产品;分析了国内外蝗虫防治对策与技术的发展现状,重点介绍了应急防治和可持续治理对策、生物防治技术、生态治理技术、信息技术、化学防治技术和施药技术等方面的进展;提出了我国蝗害绿色防控技术体系的主要内容、技术和目标;介绍了国家农业行业科研专项“我国迁移性蝗害绿色防控技术研究与示范”的主要目标和任务,预计通过此项目的实施,将促进我国蝗灾可持续治理水平的提高。
CLL-2000J新型变电站当地功能及集控系统

电力系统自动化 , 1994,
Abstract:
自动驾驶型道路交通事故责任主体认定研究

- , 2018,
Abstract: 自动驾驶技术的发展引发了既有道路交通事故责任主体认定规则的热论。较于传统道路交通事故而言,自动驾驶技术参与道路交通仅仅引发了汽车生产者和人类驾驶者共担注意义务、共享机动车支配力的事实,并未从根本上突破既有的道路交通事故处理规则。在L1—L3层级的自动驾驶型道路交通事故中,遇险而系统未能及时发出请求或告知人类驾驶者时,汽车生产者和人类驾驶者构成以累积因果关系呈现的无意思联络的数人侵权,引发对外连带责任的承担。遇险而系统已经及时发出请求或告知人类驾驶者后,人类驾驶者成为唯一的责任主体。在L4—L5层级的自动驾驶型道路交通事故中,汽车生产者完全掌握机动车运行支配,彻底取代人类驾驶者,成为唯一的责任主体。
参照经验与综合情境:对河北定州农民种地实践的一种解释
Reference Experience and Comprehensive Circumstances: An Interpretation to Peasant’s Farming Practice in Dingzhou


- , 2018,
Abstract: 在农民种地实践和行动逻辑方面有“道义小农”和“经济理性”的经典理论。这一经典论述成为部分研究者探讨当代中国农民行动逻辑的理论基础。但“道义小农”与“经济理性”的理论可作为分析工具,却不应成为我们对农民认识的限制。本文在田野调查的基础上提出,农民在种地实践中是否改变自己的种地行为,既非完全受生存伦理制约,也非完全由经济理性影响,而是在充分考虑参照经验基础上进行的选择,其所遵循的是一种实践逻辑。现实经验提醒我们要关注农民身处的综合情境,关注不同农村和农民所处具体环境的特殊性。这样才能更好地认识中国当代农民的农业实践活动以及农业现代化的转型过程。
:The “moral economy” and “economic rationality” are classic theories to interpret peasants’ farming tendency. They became theoretical basis of discussions about contemporary peasant’s logic in farming performance. This article argues that those theories can be used as analytical tools, but should not be restriction to our understanding of peasants. “Moral economy” or “economic rationality” cannot fully explain the logic that guiding peasants’ agricultural behaviors. Their farming performances are based on fully concern about reference experience. It is the logic of practice which guides peasant’s agricultural behavior. This suggests us that we should pay attention to the comprehensive circumstances which peasants faced with. Thus we can get a better understanding of the contemporary Chinese peasants and also China’s agricultural modernization process
农村土地流转中优先权的实践建构――对河北定州一农地流转案例的分析
陆益,
南京农业大学学报(社会科学版) , 2018,
Abstract: 在农村土地流转实践中,土地流转优先权虽有法律条文的规定,但主要是社会建构的结果。在河北定州的一起农村土地流转案例中,资本角色、政府角色和农户角色分别采取了"依法建构""政策动员"和"趋同从众"等行动策略,并分别建构了"村里人"优先、"支持家乡建设与发展"以及"价格优势"等土地流转优先权的社会意义,通过这种社会建构顺利实现了大规模土地流转目标。从实践建构论的视角来解读农村土地流转中优先权的建构过程,得到的启示是:农村土地的属性是复杂的,既有权属关系问题,也存在社会边界问题。因此,农村土地流转不仅仅要明确权属关系,关键还是要解决土地流转后的乡村产业和社会的整合问题。
As the progress of agriculture and rural modernization going on in the new era, problems in land subcontract will become more and more significant. In the rural land subcontract practice, the priority of subcontract is regulated in the law, mainly being the result of social construction. In the case of rural land subcontract in Dingzhou City, Hebei Province, the capital role, government roles and peasant households act respectively under the strategy of "constructing according to the law", "policy mobilization" and "convergence", and the social meanings of "villagers’ priority", "supporting hometown development" and "price advantage" were constructed respectively. Through the social construction, the large scale of land subcontract is achieved. The enlightenment of rural land subcontract priority construction is that the nature of rural is very complicated, containing property right issues, and also relating to social boundary. Therefore, not only should we clarify the property right relationship in land subcontract, but also resolve the social and industrial integration following the land subcontract in rural society
东亚飞蝗前翅感受器的类型与分布初步研究
,
华北农学报 , 2006, DOI: 10.3321/j.issn:1000-7091.2006.z1.029
Abstract: 利用扫描电镜对东亚飞蝗(Locustamigratoriamanilensis)成虫前翅感受器的外部细微结构及分布进行了观察.根据感受器的外部细微结构和分布特点,将东亚飞蝗成虫前翅感受器分为3种类型。类型Ⅰ:感受器长30~80μm,直径一般为5~10μm,基部略有膨大,表面比较光滑,主要分布在前翅背面的前缘脉域和臀脉域的基部,数量(512.6±36.0)个,以及前翅腹面的前缘脉域,中脉域和臀脉域的基部,数量(1278.8±67.8)个;类型Ⅱ:感受器长100~300μm,直径为3~5μm,着生于膨大的毛窝中,主要分布在前翅背面的前缘脉和亚前缘脉上,数量(107.8±5.4)个,以及前翅腹面的前缘脉和径脉上,数量(57.4±2.6)个。类型Ⅲ:感受器长20~40μm,直径为5~10μm,着生于膨大的毛窝中,表面有纵纹,顶部呈弧形弯曲,主要分布在前翅背腹面的肘脉和径分脉上,背面数量(95.4±2.9)个;腹面数量(38.2±1.5)个。另外,对前翅背腹面间的感受器数量的显著性比较,发现前翅背腹面间的感受器数量极显著差异(P<0.01)。对雌雄性成虫前翅感受器数量的显著性比较,发现雌虫背面的类型Ⅰ感受器和腹面的类型Ⅲ感受器的数量与雄虫有显著差异(P<0.05),其余类型感受器的数量在雌雄虫间均没有显著差异。
有机改性纳米碳酸钙的制备与性能研究
Preparation and Characterization of Nano and Organically Modified Calcium Carbonate
 [PDF]

秦岩, , 饶志
Material Sciences (MS) , 2014, DOI: 10.12677/MS.2014.43013
Abstract:

本文研究了以碳化法结合有机包覆制备纳米碳酸钙的工艺与性能。以氧化钙和二氧化碳为原料,柠檬酸为表面控制剂,并添加适量的分散剂对其进行表面改性,制备出有机改性的纳米碳酸钙。通过多种仪器手段对所制备的样品进行了形貌、粒径、元素、化学成分等定量与定性分析。结果表明,所制备的球形碳酸钙颗粒的粒径从十几纳米到几十纳米不等,存在软团聚现象,粒径分布窄,表面存在有离子键合的有机物。
This research studied the preparation technology and properties of nanometer calcium carbonate by carbonization and organic coated method. Calcium oxide and carbon dioxide were used as raw materials, citric acid was used as the surface control agent, and appropriate amount of dispersing agent was used as surface modification to prepare organically modified nano-calcium carbonate. The product was quantitatively and qualitatively analyzed by a variety of instruments, such as the morphology of the sample, size, elements and chemical composition. The results showed that the prepared calcium carbonate’s average particle size was 60 nm; there was a slight soft reunion phenomenon; particle size distribution was narrow; surface has ionic bonded organic matter.

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