检索结果-南通市图书馆

Prediction and control of surface roughness for the milling of Al/SiC metal matrix composites based on neural networks

引用

Advances in Manufacturing 2020年第4期8卷 486-507页

作者： Guo Zhou Chao Xu Yuan Ma Xiao-Hao Wang ping-fa feng Min Zhang Tsinghua-Berkeley Shenzhen Institute Tsinghua UniversityShenzhen 518055GuangdongPeople's Republic of China Shenzhen International Graduate School Tsinghua UniversityShenzhen 518055GuangdongPeople's Republic of China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084.People's Republic of China

In recent years,there has been a significant increase in the utilization of Al/SiC particulate composite materials in engineering fields,and the demand for accurate machining of such composite materials has grown *** this paper,a feed-forward multi-layered artificial neural network(ANN)roughness prediction model,using the Levenberg-Marquardt backpropagation training algorithm,is proposed to investigate the mathematical relationship between cutting parameters and average surface roughness during milling Al/SiC particulate composite *** experiments were conducted on a computer numerical control(C N C)milling machine with polycrystalline diamond(PCD)tools to acquire data for training the ANN roughness prediction *** cutting parameters were considered in these experiments:cutting speed,depth of cut,feed rate,and volume fraction of *** parameters were also used as inputs for the ANN roughness prediction *** output of the model was the average surface roughness of the machined workpiece.A successfully trained ANN roughness prediction model could predict the corresponding average surface roughness based on given cutting parameters,with a 2.08%mea n relative ***,a roughness control model that could accurately determine the corresponding cutting parameters for a specific desired roughness with a 2.91%mean relative error was developed based on the ANN roughness prediction ***,a more reliable and readable analysis of the influence of each parameter on roughness or the interaction between different parameters was conducted with the help of the ANN prediction model.

关键词： Al/SiC metal matrix composite(MMC) Surface roughness Prediction Control Neural network

来源：

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

Scaling analysis of current influence on Hastelloy surface roughness in electro-polishing process

引用

Rare Metals 2019年第2期38卷 142-150页

作者： feng feng Xiang-Song Zhang Ti-Ming Qu Yan-Yi Zhang Xiang Qian Bin-Bin Liu Jun-Long Huang ping-fa feng Division of Advanced Manufacturing Graduate School at Shenzhen Tsinghua University The State Key Laboratory of Tribology Department of Mechanical Engineering Tsinghua University Department of Physics Tsinghua University

In this study, a series of Hastelloy tapes were electro-polished, and the dividing method was used to carry out a detailed investigation on the influence of polishing current(I) on root mean square(R_q) at various image scales(L). The electro-polishing is found to be effective mainly at L smaller than 10μm, where the R_q–I relationship could be fitted by an exponential decay function with a residual roughness value. An approximate model of electro-polishing process was established to interpret the exponential decay function. This study provides a quantified insight into the electro-polishing process, which could help to obtain more understanding of its mechanism.

关键词： Surface roughness Scaling analysis Root mean square Atomic force microscopy Electro-polishing

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Modeling the optimal compensation capacitance of a giant magnetostrictive ultrasonic transducer with a loosely-coupled contactless power transfer system

引用

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2022年第10期23卷 757-770页

作者： Tian LAN ping-fa feng Jian-jian WANG Jian-fu ZHANG Hui-lin ZHOU State Key Laboratory of Tribology Department of Mechanical EngineeringTsinghua UniversityBejing 100084China'China China Ordnance Industry Navigation and Control Technology Research Institute Beijing 10089China

The giant magnetostrictive rotary ultrasonic processing system(GMUPS)with a loosely-coupled contactless power transfer(LCCPT)has emerged as a high-performance technique for the processing of hard and brittle materials,owing to its high power density.A capacitive compensation is required to achieve the highest energy efficiency of GMUPS to provide sufficient vibration amplitude when it works in the resonance *** this study,an accurate model of the optimal compensation capacitance is derived from a new electromechanical equivalent circuit model of the GMUPS with LCCPT,which consists of an equivalent mechanical circuit and an electrical *** phase lag angle between the mechanical and electrical circuits is established,taking into account the non-negligible loss in energy conversion of giant magnetostrictive material at ultrasonic *** change of system impedance characteristics and the effectiveness of the system compensation method under load are *** idle vibration experiments and machining tests are conducted to verify the developed *** results show that the GMUPS with optimal compensation capacitance can achieve the maximum idle vibration amplitude and smallest cutting *** addition,the effects of magnetic conductive material and driving voltages on the phase lag angle are also evaluated.

关键词： Rotary ultrasonic machining Giant magnetostrictive transducer(GMT) Loosely-coupled contactless power transfer(LCCPT) Electromechanical equivalent circuit Optimal compensation capacitance

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A First-principles Calculation of Structures and Stability of Al_(13)I Cluster

引用

Chinese Journal of Structural Chemistry 2006年第2期25卷 232-239页

作者： LI Gui-fa PENG ping YANG feng HAN Shao-Chang School of Materials Science ＆ Engineering Hunan University Changsha 410082 China

Using first-principles pseudo-potential plane wave method, the energetics, geometrical and electronic structures of three Al13I cluster isomers were calculated. The calculation results of the binding energy indicate Al13I cluster is more stable than Al13 cluster although its electrons are not a magic number as in Alia cluster, and among Al13I cluster isomers the ＂Bridge＂ structure is the most stable, the second is the ＂Ontop＂ structure, and the worst is the ＂Hollow＂ structure. By analyzing the geometrical structures of Al13I cluster isomers, it is found that after I atom and Al13 cluster combine the geometrical structures of Al13 moieties are changed besides Al13I Hollow cluster, in which the Alia moiety is still a regular icosahedron. For Al13I Ontop cluster, the Al13 moiety has a shrinking trend to I, whereas in Al13I Bridge cluster it is distorted. Mulliken population analysis shows for the interaction of electrons between Al-I atoms in Al13I cluster not only there exists an ionic bonding but there is a covalent bonding. Part of electrons in the Alia cluster transfer to I as Al13 cluster and I atom combine. The order of the strength of covalent bonding between Al13 moiety and I in Al13I cluster isomers is Al13IBridge〉Al13IHollow〉Al13I Ontop. Further analysis of electric structures of Al13 and Al13I clusters indicates a higher stability of Al13I cluster than Al13 cluster can be attributed to the s-p hybridization of 3s and 3p electrons of Al in Al13 moiety induced by 1 doped, which leads to fewer electrons N（EF） at EF in Al13I and a larger energy gap △EH-L between HOMO and LUMO levels in Al13I cluster. The distinguish of structural stability of Al13I cluster isomers mainly originates from their different magnitudes .in decrease of N（EF） and increase of △EH-L relative to Al13 cluster. The fewest N（EF） and the largest △EH-L are responsible for the high stability of Al13I Bridge cluster.

关键词： Al13I cluster structural stability electronic structure,pseudo-potential plane-wave method

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Cyclic oxidation behavior of NiCoCrAlY/YSZ@Ni composite coatings fabricated by laser cladding

引用

Journal of Iron and Steel Research International 2020年第10期27卷 1226-1235页

作者： Hai-zhong Zheng Pei-feng Zhou Gui-fa Li ping Peng School of Materials Science and Engineering Beihang UniversityBeijing 100191China School of Material Science and Engineering Nanchang Hangkong UniversityNanchang 330063JiangxiChina School of Material Science and Engineering Hunan UniversityChangsha 410082HunanChina

Composite coating on GH4169 alloy is prepared by laser cladding yttria-stabilized zirconia(YSZ)@Ni core-shell powdersmixed with NiCoCrAlY alloy *** cyclic oxidation behavior of the coatings,especially the growth process of theoxide layer,is investigated based on experimental research and first-principle *** results indicate that theoxidation resistance of coated GH4169 alloy is beer than that of uncoated GH4169 *** coating has three layers:acellular dendrite outer layer,a planar YSZ interlayer,and an inner layer composed of Cr2O3 formed during laser *** oxidation at 1000 and 1050℃,as the oxidation time increases,the cellular dendrite outer layer becomes thicker,andthe planar yttria-stabilized zirconia interlayer becomes *** the planar interlayer and Cr2O3 inner layer,and Al2O3 layer ***,cracks formed in the intcrface of Al2O3/Cr2O3 owing to thcir weak interface strength,whichled to the failure of the composite coating.

关键词： Laser cladding NiCoCrAlY/YSZ@Ni composite coating Cyelic oxidation-Oxidation mechanism.Crack nucleation

来源：

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

Metastable seed-crystals: epitaxial growth of branched-array organic heterostructure nanowires

引用

Science China Chemistry 2025年

作者： Jin feng Zhen-Yu Geng Ting-Yao Song Ying-Xin Ma Chuan-Zeng Wang Wei Zhang Hong-Tao Lin Jin Zhou Shu-ping Zhuo Shu-Hai Chen Xue-Dong Wang School of Chemistry and Chemical Engineering Shandong University of Technology Institute of Functional Nano & Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon-Based Functional Materials & DevicesSoochow University College of Chemistry and Chemical Engineering Hunan Normal University

Tunable light–matter interactions are exhibited by organic low-dimensional crystals, making these crystals a promising platform for organic photonics. However, the precise synthesis of organic low-dimensional crystals remains challenging due to the stochastic nature of molecular nucleation processes. Herein, the directed nucleation process is driven by the introduction of metastable seed-crystals as the trunk, which ultimately leads to branched-array organic heterostructures. The successful formation of organic heterostructures with high-density branched arrays is attributed to the highest attachment energy (Eatt（023）=-104.25 kcal mol-1) of the exposed （023） crystal plane during the seed-crystal growth route. Significantly, these as-prepared heterostructures inherently have an ultralow lattice mismatch ratio η of 0.7%between trunk and branch, which contributes to the multi-channel photon transportation. Therefore, this work provides valuable insights into a versatile synthetic strategy for accessing low-dimensional heterostructures for integrated optoelectronics.

关键词：

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Unraveling the mechanism of action of Shangxia Liangji formula for treating insomnia:a metabolomics and network pharmacology approach

引用

Traditional Medicine Research 2025年第2期10卷 16-29页

作者： Xia-Jie Quan Hao Liang Yong-Hong Tang Li Jiang Xiong-Ying Ji feng-Ying Zhang ping Zhang Bo Ouyang Department of Information The Affiliated Nanhua HospitalHengyang Medical SchoolUniversity of South ChinaHengyang 421002China Department of Neurology The Affiliated Nanhua HospitalHengyang Medical SchoolUniversity of South ChinaHengyang 421002China Department of Gastroscopy The Affiliated Nanhua HospitalHengyang Medical SchoolUniversity of South ChinaHengyang 421002China Department of Traditional Chinese Medicine The Affiliated Nanhua HospitalHengyang Medical SchoolUniversity of South ChinaHengyang 421002China

Background:Insomnia is a prevalent clinical condition and Shangxia Liangji formula(SXLJF)is a well-established method of ***,the specific mechanism of action of SXLJF remains ***:The mouse model of insomnia was established by intraperitoneal injection of ***-two mice were randomly divided into a negative control group,model group,SXLJF group(18.72 g/kg/day),and positive control group(diazepam,2 mg/kg)and treated with the corresponding drugs for 7 consecutive *** open field test and pentobarbital-induced sleeping test were ***-MS-based untargeted metabolomics and network pharmacology were applied to explore the potential targets of SXLJF for treating ***,key targets were validated using ***:Behavioral tests demonstrated that SXLJF reduced the total distance,average velocity,central distance,and sleep latency,and prolonged sleep *** and network pharmacology revealed potential targets,signaling pathways,metabolic pathways,and metabolites associated with the anti-insomnia effects of ***,tyrosine hydroxylase(TH)and tyrosine metabolism emerged as crucial metabolic pathways and targets,***-qPCR results supported the role of TH in the mechanism of SXLJF in treating ***:In conclusion,TH and tyrosine metabolism may represent significant targets and pathways for SXLJF in treating insomnia.

关键词： Shangxia Liangji formula insomnia metabolomics network pharmacology tyrosine hydroxylase tyrosine metabolism

来源：

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

Ohba's Conjecture is True for Graphs K_(t+2,3,2*(k-t-2),1*t)

引用

Acta Mathematicae Applicatae Sinica 2015年第4期31卷 1083-1090页

作者： Yu-fa SHEN feng WANG Guo-ping ZHENG Li-hua MA Department of Mathematics Hebei Normal University of Science and Technology Center for Mathematics of Hebei Province Hebei Normal University Applied Mathematics Institute Hebei University of Technology

A graph G is called chromatic-choosable if its choice number is equal to its chromatic number, namely ch（G） = X（G）. Ohba＇s conjecture states that every graph G with 2X（G）＋ 1 or fewer vertices is chromatic- choosable. It is clear that Ohba＇s conjecture is true if and only if it is true for complete multipartite graphs. Recently, Kostochka, Stiebitz and Woodall showed that Ohba＇s conjecture holds for complete multipartite graphs with partite size at most five. But the complete multipartite graphs with no restriction on their partite size, for which Ohba＇s conjecture has been verified are nothing more than the graphs Kt＋3,2.（k-t-l）,l.t by Enotomo et al., and gt＋2,3,2.（k-t-2）,l.t for t ≤ 4 by Shen et al.. In this paper, using the concept of f-choosable （or Lo-size-choosable） of graphs, we show that Ohba＇s conjecture is also true for the graphs gt＋2,3,2.（k-t-2）,l.t when t ≥ 5. Thus, Ohba＇s conjecture is true for graphs Kt＋2,3,2,（k-t-2）,l＊t for all integers t 〉 1.

关键词： list coloring chromatic-choosable graphs Ohba's conjecture f-choosable complete multipartitegraphs

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Radio jets and galaxies as cosmic string probes

引用

Frontiers of physics 2012年第4期7卷 461-470页

作者： fa-Bo feng Department of Astronomy Nanjing UniversityNanjing 210093China

The lensing effect of a cosmic string is studied, and some new methods are proposed to detect the cosmic string. The technique for using jets as extended gravitational lensing probes was first explored by Kronberg. We use the ＂alignment-breaking parameter＂ nc as a sensitive indicator of gravitational distortion by a wiggly cosmic string. Then, we applied the non-constant deflection angle to jets, and na of a specific jet is just related to the projected slope of the jet. At least three jets in the sample of Square Kilometer Array （SKA） would have significant signals （na 〉 10°） if the wiggly infinite cosmic string existed. The distortion of elliptical object is also studied and used to do a statistical research on the directions of axes and ellipticities of galaxies. In the direction of the string, we find that galaxies appear to be more elliptical for an observer and the distribution of apparent ellipticity changes correspondingly. The ellipticity distribution of current SDSS spiral sample has the signal- to-noise ratio up to 8.48 which is large enough for astronomical observations. The future survey, such as Large Synoptic Survey Telescope （LSST） and Dark Energy Survey （DES） would weaken the requirement of special geometry in the data processing. As a result, all kinds of distributions, including ellipticity axis distribution, would serve as probes to detect wiggly strings in the near future. In brief, if a wiggly cosmic string existed, these signals would be convenient to be observed with the future weak lensing survey or other surveys in the deep space. If there was no lensing signal in these distributions, it would give the upper limit of the abundance of infinite strings.

关键词： gravitational lensing jets and outflows cosmic string galaxy

来源：

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

Entropy　and　Entanglement　of　the　Electromagnetically　Induced　Transparency　System

引用

Chinese Physics Letters 2004年第6期21卷 1071-1074页

作者： LIUXiao-Juan faNGMao-fa ZHOUQing-ping DepartmentofPhysics HumanNormalUniversityChangsha410081 AnhuiInstituteofOpticsandFineMechanics ChineseAcademyofSciencesHefei230031

We study the entropy and the entanglement of an electromagnetically induced transparency system. The quantum entanglement between the atom and the two quantized laser fields is discussed by using quantum reduced entropy and that between the two quantized laser fields by using quantum relative entropy. We also examine whether influences of EIT on entropy and quantum entanglement of the system considered occur or not. Our results show that the minimum value of the atomic reduced entropy may be regarded as an entropy criterion on the electromagnetically induced transparency occurring.

关键词： Optics quantum optics and lasers

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：