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Search Results: 1 - 10 of 360078 matches for " 王远军 "
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基于泰勒展开的线性多步法构造方法的研究
A Study on Construction for Linear Multi-Step Methods Based on Taylor Expansion
 [PDF]

黄志, 胡志,
Advances in Applied Mathematics (AAM) , 2015, DOI: 10.12677/AAM.2015.44042
Abstract: 本文在前人对常微分方程初值问题的线性多步法公式研究的基础上,对于线性多步法公式中基于泰勒展开的构造方法进行了探究。我们尝试使用加权平均法构造得出了一个新的公式,随后对此给出了实例进行检验,并对构造生成新公式的原先两个公式和新公式进行了对照分析。经数值实验,该方法具有可行性,某些所得新公式在求解常微分方程初值问题中具有较高稳定性和较小误差。
Following the previous literature on multi-step formulae for initial value problems of ODEs (ordi-nary differential equations), we study the construction for linear multi-step methods based on Taylor expansion in this paper. We try the weighted average method and derive a new formula. Then we check this new method in an example, and compare the original two formulae and con-structed new formula. Via such numerical experiment, this method is reliable. Some constructed new formulae can have relatively high stability and small error while solving ODEs initial value problems.
近十年来我国能源消费变化及未来发展趋势
Decade Change of Energy Consumption and Its Development Trend in China
 [PDF]

, 吉威宁, 崔武, 武洪强, 苑中显
Sustainable Energy (SE) , 2013, DOI: 10.12677/SE.2013.32003
Abstract: 本文对我国最近十年以来能源消费总量及能源结构的变化情况进行了讨论,并与世界能源发展状况作了对比。汇总了我国分部门近年来的耗能数据,并着重分析了钢铁、水泥和有色冶金等重点行业的能耗变化。将我国一些重点工业产品的单位能耗水平及单位GDP能耗水平与国际水平进行了比对。最后,结合国家能源战略,讨论了我国未来的能源发展趋势。
The decade change of the total energy consumption and the energy structure of Chinais discussed and compared to the world’s energy data. The subdivision of the energy consumption to different branches is paid attention. Among the industrial enterprises, steel, cement and nonferrous metallurgy have been especially emphasized for their big role in terms of the energy cost. The Chinese energy consumption per capita for some typical products as well as per unit GDP is also compared to those international levels. Finally, taking into account of the national energy strategy, the energy development trend in the future ofChinais discussed briefly.
超临界火电机组实时仿真的水和水蒸气模型
,广
重庆大学学报 , 2005, DOI: 10.11835/j.issn.1000-582X.2005.10.013
Abstract: 以热力学基础理论为依据,推导出过热水蒸气热力参数的数学模型,该模型包括水蒸气的比焓、比容、定压比热以及比熵公式.在1985年国际水蒸气骨架表允差范围内,对于水蒸气比焓公式,其压力适用范围为0~90MPa;对于水蒸气比容公式,其压力适用范围为0~40MPa,而模型中使用的温度范围均为273.15~1073.15K.该模型适用于超临界火电机组实时仿真,便于工程实用.
露天矿采场路面抑尘剂研制及性能表征
胡树, 李利,
金属矿山 , 2013,
Abstract: 基于露天采场路面扬尘特点及机理的分析,确定抑尘剂组分。通过吸湿剂、凝并剂、表面活性剂单体选择试验,初步确定单体及浓度范围。基于正交试验,以失水率为评价指标,确定了最优配方,并对其自然环境下的吸湿放湿性、抗风吹等性能进行了测试。结果表明,研究出的抑尘剂具有较好的吸湿、保水性能,干燥条件下,表面强度高,固结性能好,具有较好的防尘抑尘性能,且材料来源广泛、制备简单、成本低,具有较好的应用前景。
计算边坡安全系数的坡向离心法
正中,牟声,
岩土力学 , 2009,
Abstract: 边坡稳定分析方法发展最引人注目,它是经典土力学最早试图解决而至今仍未圆满解决的课题。在常用边坡分析方法的基础上,从边坡失稳机制出发,提出一种更方便的安全系数计算方法——坡向离心法。该法通过不断增大水平加速度,直至边坡失稳为止,依据水平加速度与重力加速度失稳影响机制求得安全系数。通过算例与传统极限平衡法和有限元强度折减法相比较,并对各物理参数进行敏感性分析。结果表明,坡向离心法在边坡工程稳定分析中的应用是切实可行的,其弹性模量和泊松比对该法所求安全系数影响不大。
基于属性层次模型的柴油机故障证据融合方法
,徐久,严志
- , 2018, DOI: 10.13195/j.kzyjc.2017.0214
Abstract: 针对证据理论在覆盖率高的柴油机故障诊断中容易出现证据融合误差的问题,提出一种基于属性层次模型的证据融合方法.首先,通过余弦相似度改进目标层权重算法,得到反映目标层不同证据源差异的本质差异因子;然后,采用贝叶斯网络规则改进属性层权重算法,计算相关联的属性层证据源熵值权重;最后,通过故障层次关联特性和CWAA算子修正证据理论融合规则,将不同层次属性权重有效融合,减少系统复杂性引起的诊断误差.在R6105AZLD柴油机台架上的实验结果表明,引入所提方法后的诊断准确度和鲁棒性大幅提高.
基于多属性群决策的柴油机故障证据融合方法
,徐久,严志
大连海事大学学报 , 2018,
Abstract: 鉴于复杂机械系统中故障信息的不完备及不确定性造成证据理论在故障诊断决策级阶段融合的准确性问题,提出基于多属性群决策的故障证据融合方法.利用多属性群决策的属性分析,计算基于元素属性集合的决策体差异权重,以减小融合证据源的差异;结合柴油机目标故障的相似依赖关系,利用目标故障的可信度权重对冲突焦元信息再分配,旨在提高证据融合的准确性.对R6105AZLD柴油机台架试验结果表明:本文方法可大幅提高诊断准确度和鲁棒性.
In view of accuracy of evidence theory in the stage of fault diagnosis decision fusion by incompleteness and uncertainty of fault information in complex mechanical systems, the method of fault evidence fusion based on multi-attribute group decision making was proposed. By using attribute analysis of multi-attribute group decision making, the weight of decision body based on element attribute set was calculated to reduce the difference of fusion evidence sources. Based on the similarity dependence of the target fault of the diesel engine, by using the reliability weight of the target fault, the conflicting focal element was redistributed to improve the accuracy of the evidence fusion. The results of R6105AZLD diesel engine bench test show that the proposed method can greatly improve diagnostic accuracy and robustness.
麦秸全量还田下太湖地区两种典型水稻土稻季氨挥发特性比较
,德建,张刚,
环境科学 , 2013,
Abstract: 利用原状土柱在田间试验条件下,比较了麦秸还田下乌栅土和黄泥土稻季氮素氨挥发损失规律,每种试验土壤均设对照、氮肥、氮肥加麦秆这3个处理,同步测定施肥后氨挥发、田面水铵态氮浓度与pH、以及表层土壤Eh.结果表明,乌栅土氨挥发速率及其累积氨挥发量显著高于黄泥土,两种土壤的稻季平均氨挥发的氮素损失量分别为41.8kg·hm-2和11.2kg·hm-2,分别占氮肥用量的15.2%和3.8%;在3个施肥时期中,分蘖肥期氨挥发损失率最高,乌栅土和黄泥土分别占氮肥用量的29.4%和8.3%;麦秸还田显著增加了氮肥的氨挥发损失,麦秸还田下乌栅土和黄泥土稻季氨挥发损失比单施氮肥处理分别增加了19.8%和20.6%.两种土壤氨挥发速率均与田面水NH4+-N浓度、pH呈正相关关系,但与表层土壤Eh的关系还需进一步研究.
唾液腺核素显像方法的优化
程弘,马宏星,
- , 2016, DOI: 10.16118/j.1008-0392.2016.04.017
Abstract: 目的探讨唾液腺核素显像方法的优化。方法 对148例疑似干燥综合征(Sjgren's syndrome, SS)患者 进行唾液腺核素显像,其中58例用30分钟法,90例用15分钟法,以实验室检查作为对比组,临床诊断作为标准,分别进行统计学分析。结果 在灵敏度、特异度以及准确率30分钟法分别为97.62%(41/42)、26.67%(5/16)、78.95%(46/58),15分钟法为93.85%(61/65)、84.00%(21/25)、91.11%(82/90)。30分钟法与实验室检查提示特异度差异有统计学(P<0.05),15分钟法与实验室检查差异无统计学意义;30分钟法与15分钟法提示在特异度以及准确率上有统计学差异。结论 15分钟法能显著减少患者图像采集时间、提高检查准确率,值得在临床推广。
Objective To explore the optimization of salivary gland scintigraphy. Methods One hundred and forty eight patients with suspected Sjgren's syndrome(SS) underwent scintigraphic salivary gland imaging, including 59 cases using 30min method and 90 cases using 15min method. With clinical diagnosis as gold standard and laboratory results as controls, the sensitivity, specificity and accuracy of two scintigraphic methods were evaluated. Results The sensitivity, specificity, accuracy of 30min method were 97.62%(41/42),26.67%(5/16) and 78.95%(46/58); and those of 15min method were 93.85%(61/65),84.00%(21/25) and 91.11%(82/90), respectively. There were significant differences between 30min method and laboratory examination in specificity and sensibility (P<0.05); while no differences between 15min method and laboratory examination. There were also significant differences in specificity and accuracy between 30min method and 15min method. Conclusion Scintigraphy of salivary gland imaging with 15min method is more accurate and less time-consuming than that of 30min method in diagnosis of SS
医学图像细微结构增强方法研究进展
Research progress of details enhancement methods in medical images

,靳珍怡,
- , 2018, DOI: 10.7507/1001-5515.201705055
Abstract: 有效的医学图像增强方法可以增强感兴趣目标或区域以及抑制背景及噪声区域,从而改善图像的质量,在减少噪声的同时保持原有的几何纹理结构,基于增强后的图像可以更方便地诊断疾病。本文针对当前医学图像细微结构增强方法展开研究,主要包括锐化增强方法、粗糙集与模糊集增强、多尺度几何增强以及基于微分算子的增强方法。最后给出几种常用的图像细节增强定量评价指标,并探讨了医学图像细微结构增强进一步的研究方向。
Effective medical image enhancement method can not only highlight the interested target and region, but also suppress the background and noise, thus improving the quality of the image and reducing the noise while keeping the original geometric structure, which contributes to easier diagnosis in disease based on the image enhanced. This article carries out research on strengthening methods of subtle structure in medical image nowadays, including images sharpening enhancement, rough sets and fuzzy sets, multi-scale geometrical analysis and differential operator. Finally, some commonly used quantitative evaluation criteria of image detail enhancement are given, and further research directions of fine structure enhancement of medical images are discussed.
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