检索结果-南通市图书馆

Numerical Simulation of Spray Characteristics of an Effervescent Atomizer

在线全文

学校读者我要写书评

暂无评论

International Journal of Plant Engineering and Management 2009年第2期14卷 108-112页

作者： xiao Ji-ming TU Yong-tao LI peng-yang TANG xiao-peng Xi'an University of Technology Xi'an 710048 China

Using fluid dynamics software Fluent, the spray characteristics of an effervescent atomizer in a downstream flow field was simulated and analyzed, the results show that on the cross sections of the atomizer downstream flow field, the distribution of the atomized droplet size is small and mainly concentrated about Sauter mean diameter （ SMD）, and the distribution of the axial velocity is large, but mainly concentrated about the gas peak velocity in the closer nozzle axis area; the gas peak velocity of the atomized droplet increases, while the droplet SMD decreases with increase of the nozzle caliber and the air pressure; with the increase of the flow rate of cuttingfluid, the atomized droplet SMD increases, while the gas peak velocity rises first and then decreases, but the decrease trend is very small after the air pressure is more than 0. 4 MPa. The simulation results have significance in guiding for designing and applying the effervescent atomizer.

关键词： minimal quantity lubrication effervescent atomization spray characteristics numerical simulation

在线全文

学校读者我要写书评

暂无评论

基于谓词分类的语义缓存查询裁剪

华南理工大学学报（自然科学版） 2008年第1期36卷 44-49页

作者：李东杨小鹏罗鹏飞华南理工大学计算机科学与工程学院广东广州510640 华南理工大学软件学院广东广州510006

为了解决传统查询裁剪在时间和空间上的高复杂性,提出了一种基于谓词分类的语义缓存查询裁剪算法.首先从语义上将谓词分成范围谓词和约束谓词两类,并分别对这两类谓词进行"满足"、"相交"和"包含"的定义;然后基于谓词分类提出了一种新的... 详细信息

为了解决传统查询裁剪在时间和空间上的高复杂性,提出了一种基于谓词分类的语义缓存查询裁剪算法.首先从语义上将谓词分成范围谓词和约束谓词两类,并分别对这两类谓词进行"满足"、"相交"和"包含"的定义;然后基于谓词分类提出了一种新的查询裁剪算法,并对算法的复杂度进行了分析.模拟实验结果表明,所提出的裁剪算法是有效的,特别是在处理查询和缓存相交的情况下,与基于谓词模型的传统串型裁剪算法和基于逻辑规则的裁剪算法相比,文中算法可明显改善查询裁剪效率.

关键词：查询裁剪语义约束式范围式语义缓存

Electrochemical conversion of methane to bridge the gap in the artificial carbon cycle

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2025年第1期100卷 286-308页

作者： Yuhao peng Yuefeng Song Ihar Razanau Juanxiu xiao Wei xiao Di Hu Guoxiong Wang College of Chemistry and Molecular Sciences Hubei Key Laboratory of Electrochemical Power Sources Wuhan University State Key Laboratory of Catalysis Dalian National Laboratory for Clean Energy iChEM (Collaborative Innovation Center of Chemistry for Energy Materials) Dalian Institute of Chemical Physics Chinese Academy of Sciences Laboratory of Physical-Chemical Technologies SSPA Scientific and Practical Materials Research Centre of NAS of Belarus State Key Laboratory of Marine Resources Utilization in South China Sea Collaborative Innovation Center of Marine Science and Technology School of Marine Science and Engineering Hainan University Department of Chemical and Environmental Engineering University of Nottingham Ningbo China

Methane, an abundant one-carbon（C1） resource, is extensively used in the industrial production of vital fuels and value-added chemicals. However, current industrial methane conversion technologies are energy-and carbon-intensive, mainly due to the high activation energy required to break the inert C–H bond, low selectivity, and problematic side reactions, including CO2emissions and coke deposition. Electrochemical conversion of methane（ECM） using intermittent renewable energy offers an attractive solution, due to its modular reactor design and operational flexibility across a broad spectrum of temperatures and pressures. This review emphasizes conversion pathways of methane in various reaction systems, highlighting the significance and advantages of ECM in facilitating a sustainable artificial carbon cycle. This work provides a comprehensive overview of conventional methane activation mechanisms and delineates the complete pathways of methane conversion in electrolysis contexts. Based on surface/interface chemistry, this work systematically analyzes proposed reaction pathways and corresponding strategies to enhance ECM efficiency towards various target products, including syngas, hydrocarbons, oxygenates, and advanced carbon materials. The discussion also encompasses opportunities and challenges for the ECM process, including insights into ECM pathways, rational electrocatalyst design, establishment of benchmarking protocols, electrolyte engineering, enhancement of CH4conversion rates, and minimization of CO2emission.

关键词： Activation energy

Reduced mesencephalic astrocyte-derived neurotrophic factor expression by mutant androgen receptor contributes to neurodegeneration in a model of spinal and bulbar muscular atrophy pathology

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第9期20卷 2655-2666页

作者： Yiyang Qin Wenzhen Zhu Tingting Guo Yiran Zhang Tingting Xing peng Yin Shihua Li xiao-Jiang Li Su yang Guangdong Key Laboratory of Non-human Primate Research Key Laboratory of CNS Regeneration(Ministry of Education)Guangdong–HongKong–Macao Institute of CNS RegenerationJinan UniversityGuangzhouGuangdong ProvinceChina

Spinal and bulbar muscular atrophy is a neurodegenerative disease caused by extended CAG trinucleotide repeats in the androgen receptor gene,which encodes a ligand-dependent transcription facto *** mutant androgen receptor protein,characterized by polyglutamine expansion,is prone to misfolding and forms aggregates in both the nucleus and cytoplasm in the brain in spinal and bulbar muscular atrophy *** aggregates alter protein-protein interactions and compromise transcriptional *** this study,we reported that in both cultured N2a cells and mouse brain,mutant androgen receptor with polyglutamine expansion causes reduced expression of mesencephalic astrocyte-de rived neurotrophic *** n of mesencephalic astrocyte-derived neurotrophic factor amelio rated the neurotoxicity of mutant androgen receptor through the inhibition of mutant androgen receptor *** down endogenous mesencephalic astrocyte-derived neurotrophic factor in the mouse brain exacerbated neuronal damage and mutant androgen receptor *** findings suggest that inhibition of mesencephalic astrocyte-derived neurotrophic factor expression by mutant androgen receptor is a potential mechanism underlying neurodegeneration in spinal and bulbar muscular atrophy.

关键词： androgen receptor mesencephalic astrocyte-derived neurotrophic factor mouse model neurodegeneration neuronal loss neurotrophic factor polyglutamine disease protein misfolding spinal and bulbar muscular atrophy transcription factor

Observation of acoustic hybrid topological phases induced by the p-d orbital interactions

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 132-139页

作者： xiao Xiang Feng Gao Yu-Gui peng peng Wu Zong-Lin Li Xue-Feng Zhu School of Physics and Innovation Institute Huazhong University of Science and Technology

In spinless systems,growing attention has recently been attracted to synthetic gauge fields,which redefine the fundamental crystal symmetries by utilizing the projective algebraic ***,synthetic gauge fields have been commonly investigated in single orbital systems,and explorations on hybrid orbitals remain elusive in ***,we report the experimental observation of hybrid topological phases induced by hybrid synthetic gauge flux,which is formed by the interaction between p and d orbitals embedded in acoustic *** breaking the translation symmetries of Lxand/or Ly,we unambiguously demonstrate the first-order M?bius edge states and higher-order corner *** work establishes a platform for seeking exotic topological phases induced by hybrid-orbitals interactions and initializing the framework of hybrid-orbitalsrelated topological *** applications can be anticipated in scenarios such as high-quality sensing and robust wave trapping due to the stepwise energy distribution of the hybrid topological phase.

关键词： topological insulator synthetic gauge field projective symmetry corner states

Expression of hepatocyte growth factor and its receptor c-Met in lens-induced myopia in guinea pigs

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Medical Journal 2013年第23期126卷 4524-4527页

作者： LI Xiu-juan yang xiao-peng WAN Guang-ming WANG Yu-ying ZHANG Jin-song Department of Ophthalmology the First Affiliated Hospital of Zhengzhou University Zhengzhou Henan 450052 China Department of Medical Equipment the First Affiliated Hospital of Zhengzhou University Zhengzhou Henan 450052 China

Background Myopia is a common disorder and the incidence has increased yearly,but its pathogenesis remains *** aim of this study was to investigate the possible role of hepatocyte growth factor （HGF） and its receptor c-Met in the development of lens-induced myopia in guinea *** Sixty one-week-old guinea pigs were *** right eyes were treated with-10.0 diopters （D） lenses as the lens-induced myopia group; the left eyes remained untreated as the control *** weeks later,refractive status and axial length were determined by streak retinoscopy and A-scan ultrasonography,*** guinea pigs were killed and both eyes *** changes were observed by hematoxylin and eosin *** expression levels of HGF,c-Met,and matrix metalloproteinase 2 （MMP-2） mRNA and protein in the posterior sclera were analyzed by RT-PCR and Western blotting,*** The lens-induced myopia group became myopic with a significant increase in axial length and a significant decrease in *** with the control group,the posterior retina and sclera were thinner in the lens-induced myopia *** expression levels of HGF and MMP-2 mRNA and protein and of phosphorylated c-Met protein were significantly higher in the posterior sclera of the lens-induced myopia group than in the control group （all P ＜0.05）.In the lens-induced myopia group,the expression level of MMP-2 in the posterior sclera positively correlated with the expression level of HGF （r=0.902,P ＜0.05） and phosphorylated c-Met （r=0.885,P ＜0.05）.Conclusion HGF/c-Met might play a role in the development of lens-induced myopia in guinea pigs by upregulating the expression of MMP-2.

关键词： myopia sclera hepatocyte growth factor MMP-2

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

有限厚无限大平板超导体模型场分布的严格解

物理学报 2007年第9期56卷 5033-5036页

作者：杨鹏飞白晋涛杨小鹏西北大学光子学与光子技术研究所陕西广播电视大学榆林市分校榆林719000 榆林市工业学校

给出了有限厚无限大平面板超导体模型场分布的严格解,确证了文献中近似结果的有效性.

关键词：严格解 Jacobi椭圆函数超导

在线全文

学校读者我要写书评

暂无评论

稳健的相干干扰抑制算法

信号处理 2017年第12期33卷 1555-1561页

作者：刘力杨小鹏北京理工大学信息与电子学院雷达技术研究所北京100081 卫星导航电子信息技术教育部重点实验室(北京理工大学) 北京100081

针对自适应波束形成在干扰位置扰动以及存在相干干扰时的性能下降问题,提出了一种稳健的相干干扰抑制算法。该算法首先估计出相干干扰的来波方向,然后以期望方向增益最大,旁瓣方向增益最小为条件建立波束权矢量求解的优化问题,并利用干... 详细信息

针对自适应波束形成在干扰位置扰动以及存在相干干扰时的性能下降问题,提出了一种稳健的相干干扰抑制算法。该算法首先估计出相干干扰的来波方向,然后以期望方向增益最大,旁瓣方向增益最小为条件建立波束权矢量求解的优化问题,并利用干扰零陷展宽方向增益的二范数小于控制系数作为约束条件来克服干扰扰动。与已有的自适应算法相比,本文所提方法求解权矢量不需要采样数据协方差矩阵求逆过程,对快拍数要求低,能有效控制零限宽度和深度,对转发式相干干扰和干扰平台抖动具有良好的抗干扰效果。仿真结果证明了所提方法的有效性和稳健性。

关键词：波达方向估计稳健性相干干扰波束形成零限展宽

在线全文

学校读者我要写书评

暂无评论

基于导数约束的互谱降秩自适应波束形成

北京理工大学学报 2011年第9期31卷 1095-1099页

作者：刘永旭杨小鹏龙腾北京理工大学雷达技术研究所北京100081

在导数约束基础上,提出了一种对阵列导向矢量失配稳健的互谱降秩自适应波束形成算法.通过在期望方向上设置多个线性导数约束,对阵列接收数据进行利用互谱能量的降秩处理,然后进行自适应波束形成.该算法不仅能够在导向矢量失配情况下获... 详细信息

在导数约束基础上,提出了一种对阵列导向矢量失配稳健的互谱降秩自适应波束形成算法.通过在期望方向上设置多个线性导数约束,对阵列接收数据进行利用互谱能量的降秩处理,然后进行自适应波束形成.该算法不仅能够在导向矢量失配情况下获得较好的性能,并且弥补了传统稳健自适应波束形成算法运算量大的缺点.仿真分析表明,所提出的算法具有较好的稳健性能.

关键词：阵列信号处理自适应波束形成导数约束稳健性降秩