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Dual-frequency piezoelectric micromachined ultrasound transducer based on polarization switching in ferroelectric thin films

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Microsystems & Nanoengineering 2023年第5期9卷 233-243页

作者： Jin Soo Park Soo Young Jung dong Hun kim Jung Ho Park Ho Won Jang Tae Geun kim Seung-Hyub Baek Byung Chul Lee Bionics Research Center Korea Institute of Science and TechnologySeoul 02792Republic of Korea Department of Electrical Engineering Korea UniversitySeoul 02841Republic of Korea Center for Electronic Materials Korea Institute of Science and TechnologySeoul 02792Republic of Korea Department of Material Science and Engineering Seoul National UniversitySeoul 08826Republic of Korea Division of Bio-Medical Science and Technology KIST SchoolUniversity of Science and Technology(UST)Seoul 02792Republic of Korea KHU-KIST Department of Converging Science and Technology Kyung Hee UniversitySeoul 02447Republic of Korea

Due to its additional frequency response,dual-frequency ultrasound has advantages over conventional ultrasound,which operates at a specific frequency ***,a tunable frequency from a single transducer enables sonographers to achieve ultrasound images with a large detection area and high *** facilitates the availability of more advanced techniques that simultaneously require low-and high-frequency ultrasounds,such as harmonic imaging and image-guided *** this study,we present a novel method for dual-frequency ultrasound generation from a ferroelectric piezoelectric micromachined ultrasound transducer(PMUT).Uniformly designed transducer arrays can be used for both deep low-resolution imaging and shallow high-resolution *** switch the ultrasound frequency,the only requirement is to tune a DC bias to control the polarization state of the ferroelectric *** vibration of the PMUT membrane strongly depends on the polarization state,producing low-and high-frequency ultrasounds from a single excitation *** strategy for dual-frequency ultrasounds meets the requirement for either multielectrode configurations or heterodesigned elements,which are integrated into an ***,this technique significantly reduces the design complexity of transducer arrays and their associated driving circuits.

关键词： piezoelectric ferroelectric enable

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鼠李糖脂发酵条件优化和采油应用研究

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深圳大学学报（理工版） 2010年第4期27卷 482-489页

作者：夏文杰董汉平俞理中国科学院渗流流体力学研究所河北廊坊065007

铜绿假单胞菌WJ-1是从内蒙古自治区蒙古林油藏地层水中经筛选和驯化得到的一株兼性厌氧高产生物表面活性剂的烃降解菌株.经薄层层析、高效液相色谱及红外光谱分析,发现该菌株发酵的表面活性剂主要为鼠李糖脂(rhamnolipid,RL).运用单因... 详细信息

铜绿假单胞菌WJ-1是从内蒙古自治区蒙古林油藏地层水中经筛选和驯化得到的一株兼性厌氧高产生物表面活性剂的烃降解菌株.经薄层层析、高效液相色谱及红外光谱分析,发现该菌株发酵的表面活性剂主要为鼠李糖脂(rhamnolipid,RL).运用单因素实验和正交实验对菌株WJ-1合成RL的发酵条件进行优化,获得最佳培养基,碳源为葵籽油80g/L,氮源为NaNO310g/L、K2HPO42g/L、CaCl20.12g/L、MgSO40.24g/L、FeSO40.12g/L、Na2MoO40.08g/L和酵母膏1.2g/L.菌体生长最适pH为7.0,最适温度为37℃;RL合成最适pH为7.5,最适温度为34℃,最适发酵时间为90～100h.在最优条件下使用3T智能发酵罐发酵,RL的产量达到55.1g/***粗品能将水表面张力从72.14mN/m降至25.01mN/m,临界胶束浓度为22mg/L.物理模拟驱油试验表明,铜绿假单胞菌WJ-1产出的RL在微生物采油上将有良好应用前景.

关键词：微生物采油铜绿假单胞菌生物表面活性剂鼠李糖脂驱油物理模拟

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Stability for Leipholz’s Type of Laminated Box Columns with Nonsymmetric Lay-Ups on Elastic Foundation

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Advances in Applied Mathematics and Mechanics 2015年第2期7卷 158-179页

作者： Nam-Il kim Jaehong Lee Department of Architectural Engineering Sejong University98 Kunja DongKwangjin KuSeoul 143-747Korea

The stability behavior of the Leipholz’s type of laminated box columns with nonsymmetric lay-ups resting on elastic foundation is investigated using theﬁnite el-ement *** on the kinematic assumptions consistent with the Vlasov beam theory,a formal engineering approach of the mechanics of the laminated box column-s with symmetric and nonsymmetric lay-ups is *** extended Hamilton’s principle is employed to obtain the elastic stiffness and mass matrices,the Rayleigh damping and elastic foundation matrices,the geometric stiffness matrix due to dis-tributed axial force,and the load correction stiffness matrix accounting for the uni-formly distributed nonconservative *** evaluation procedures for the critical values of divergence andﬂutter loads with/without internal and external damping ef-fects are brieﬂy *** examples are carried out to validate the present theory with respect to the previously published ***,the inﬂuences of theﬁber angle change and damping on the divergence andﬂutter loads of the laminated box columns are parametrically investigated.

关键词： Leipholz column laminate stability divergence ﬂutter ﬁnite element analysis

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Heterogeneous self-healing assembly of MXene and graphene oxide enables producing free-standing and self-reparable soft electronics and robots

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Science Bulletin 2022年第5期67卷 501-511,M0004页

作者： Jia-Nan Ma Yong-Lai Zhang Yu-Qing Liu dong-dong han Jiang-Wei Mao Jia-Rui Zhang Wu-Chao Zhao Hong-Bo Sun State Key Laboratory of Integrated Optoelectronics College of Electronic Science and EngineeringJilin UniversityChangchun 130012China State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision InstrumentTsinghua UniversityBeijing 100084China State Key Laboratory of Supramolecular Structure and Materials College of ChemistryJilin UniversityChangchun 130012China

Self-healing materials(SHMs)with unique mechanical and electronic properties are promising for self-reparable electronics and ***,the self-healing ability of emerging two-dimensional(2D)materials,for instance,MXenes,has not been systematically investigated,which limits their applications in self-healing ***,we report the homogeneous self-healing assembly(homoSHA)of MXene and the heterogeneous self-healing assembly(hetero-SHA)of MXene and graphene oxide(GO)under moisture *** self-healing mechanism has been attributed to the hydration induced interlayer swelling of MXene and GO and the recombination of hydrogen bond networks after water *** multiform hetero-SHA of MXene and GO not only enables facile fabrication of free-standing soft electronics and robots,but also endows the resultant devices with damage-healing *** proof-of-concept demonstrations,free-standing soft electronic devices including a generator,a humidity sensor,a pressure sensor,and several robotic devices have been *** hetero-SHA of MXene and GO is simple yet effective,and it may pioneer a new avenue to develop miniature soft electronics and robots based on 2D materials.

关键词： MXene elf-healing Graphene oxide Soft electronics Soft robots

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分子间相互作用对芳杂环聚合物PBO光谱性能影响的理论研究

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华东理工大学学报（自然科学版） 2007年第2期33卷 205-210页

作者：庄启昕冯东东吴平平韩哲文华东理工大学材料科学与工程学院超细材料制备与应用教育部重点实验室上海200237 上海三爱富新材料股份有限公司上海200241

采用量子化学计算方法AM1-ZINDO/CI对芳杂环聚合物PBO的光物理性能进行研究。结果表明:PBO分子链共轭平面结构间的面面相互作用,影响到前沿分子轨道的电子跃迁方式,从而导致聚集态电子光谱相对于理论单分子链存在红移现象。由含3个单元... 详细信息

采用量子化学计算方法AM1-ZINDO/CI对芳杂环聚合物PBO的光物理性能进行研究。结果表明:PBO分子链共轭平面结构间的面面相互作用,影响到前沿分子轨道的电子跃迁方式,从而导致聚集态电子光谱相对于理论单分子链存在红移现象。由含3个单元的PBO聚集态分子模型模拟计算显示,PBO分子链共轭平面结构间的面面相互作用使得电子光谱最大吸收峰由383.06 nm红移至407.19 nm。结合同系线性规律,推导出PBO聚合物聚集态的电子光谱最大吸收峰为425.33 nm,从本征结构上解释了PBO聚集态电子光谱的光谱性质。

关键词：量子化学光物理性能芳杂环聚合物

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Formation of photo-reactive heterostructure from a multicomponent amorphous alloy with atomically random distribution

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Journal of Materials Science & Technology 2022年第14期109卷 245-253页

作者： Hae Jin Park Hee Jin Lee Tae Kyung kim Sung Hwan Hong Wei-Min Wang Taek Jib Choi Ki Buem kim Department of Nanotechnology and Advanced Materials Engineering Sejong University209 Neung dong-roGwangjin-guSeoul 05006Republic of Korea Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Ministry of EducationShandong UniversityJinan 250061China

In this study,metallic glass is designed tunable for promising functional applications via a facile and stable,one-step *** approach about alloy design and process is based on the unique properties of the Ti-Cu-Ni-Sn metallic glass that are afforded by the varying oxygen affinities of the four constituent *** metallic glass exhibits homogeneous nucleation of oxides and uniform formation of the various metal *** alloy design and hydrothermal synthesis to customize the metallic glasses are the most critical factors that determine the characteristics of the metal oxides and the resulting nanostructures and photoelectrode *** enables the desired element to be selectively grown via a facile single-step *** results provide a promising road map for the application of metallic glasses to photoelectrochemical(PEC)solar water splitting,as well as various other new possibilities.

关键词： Metallic glass Alloy design Hydrothermal synthesis Metal oxide Water splitting

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基于PRESENT算法的RFID安全认证协议

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通信学报 2015年第S1期36卷 65-74页

作者：张兴韩冬曹光辉贾旭辽宁工业大学电子与信息工程学院辽宁锦州121001

物联网中RFID技术的应用非常广泛,但是RFID系统的安全性却存在着很大隐患。在RFID系统中标签与读写器间的通信信道是最易受到攻击,传输数据的完整性与保密性得不到保障,因而需要加强RFID系统通信的安全机制。考虑到RFID系统的硬件条件... 详细信息

物联网中RFID技术的应用非常广泛,但是RFID系统的安全性却存在着很大隐患。在RFID系统中标签与读写器间的通信信道是最易受到攻击,传输数据的完整性与保密性得不到保障,因而需要加强RFID系统通信的安全机制。考虑到RFID系统的硬件条件与成本限制,需要建立一个适合RFID系统的安全认证协议,来解决在RFID系统中信息传输所遇到的安全问题。PRESENT算法是轻量级的分组加密算法,将PRESENT结合到RFID系统的安全认证协议中,形成了新的RFID安全认证协议PRSA(PRESENT based RFID security authentication)。此协议可以增强RFID系统的安全性而又不会占用过多的硬件资源,从而能够适用于低成本的RFID系统的通信安全。

关键词：物联网 RFID系统安全认证协议 PRESENT算法

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自适应控制深度学习和知识挖掘图像分类

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沈阳工业大学学报 2018年第3期40卷 334-339页

作者：王春华韩栋黄淮学院动画学院河南驻马店463000 黄淮学院信息工程学院河南驻马店463000

针对传统分类方法的局限性,提出了一种深度学习结合知识挖掘的零样本图像自适应控制图像分类算法.利用对图像属性的深度学习来实现图像深层次特征及属性的学习和预测,基于图像的属性-类别映射使分类器性能有较大差异,通过稀疏表示模型... 详细信息

针对传统分类方法的局限性,提出了一种深度学习结合知识挖掘的零样本图像自适应控制图像分类算法.利用对图像属性的深度学习来实现图像深层次特征及属性的学习和预测,基于图像的属性-类别映射使分类器性能有较大差异,通过稀疏表示模型挖掘图像类别和属性之间的关系并设计自适应控制的属性分类器实现对图像的分类操作.结果表明,与DBN和SVM算法相比,在监督模式和零样本模式下,该算法具有较高的属性预测准确度.在零样本情况下对Shoes数据集进行分类时,该算法具有最高的准确分类识别率,比其他算法的分类识别率提高了15%.

关键词：深度学习知识挖掘卷积神经网络图像分类零样本支持向量机深度置信网络分类器

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复杂服役工况下取向硅钢的磁特性与铁心材料选型

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材料导报 2019年第14期33卷 2413-2418页

作者：程灵杨富尧马光孟利陈新韩钰董瀚钢铁研究总院冶金工艺研究所北京100081 全球能源互联网研究院有限公司先进输电技术国家重点实验室北京102211

本工作基于直流偏置量和励磁信号波形精确可控的软磁测量系统,研究了交直流混合激励条件下0.20mm、0.23mm、0.27mm及0.30mm规格共14个高牌号取向硅钢的磁性能及磁致伸缩性能,并考虑取向硅钢在复杂工况下的磁特性,针对受高压直流输电地... 详细信息

本工作基于直流偏置量和励磁信号波形精确可控的软磁测量系统,研究了交直流混合激励条件下0.20mm、0.23mm、0.27mm及0.30mm规格共14个高牌号取向硅钢的磁性能及磁致伸缩性能,并考虑取向硅钢在复杂工况下的磁特性,针对受高压直流输电地中电流影响较大的交流变压器、直流偏磁与高次谐波工况同时存在的换流变压器以及含谐波工况的一般交流电力变压器开展了铁心材料选型研究。结果表明,对于正常工况下铁损相同的取向硅钢材料,厚规格、低磁感取向硅钢在直流偏磁条件下损耗及励磁电流更小,而薄规格取向硅钢在谐波工况下的损耗更低,并进一步揭示了造成该现象的原因。针对上述三类电力变压器,分别提出了不同铁损、公称厚度、磁感应强度及表面张力取向硅钢材料在铁心材料中的选用建议。

关键词：取向硅钢电力变压器磁特性材料选型

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Experiences with Constructed Wetland Systems in Korea

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Journal of Ocean University of China 2006年第4期5卷 345-350页

作者： kim Youngchul Hwang Gilson Lee Jin-Woo Park Je-Chul kim dong-Sup Kang Min-Gi Chang In-Soung Department of Environmental Engineering Hanseo University Seosan Chungnam 356-820 Korea Water Environment Research Center Ansan Korea Dohwa Consulting Engineers Co. Ltd Seoul Korea Department of Environmental Engineering Kumho University Gumi Korea Korea Water Resource Corporation Daejeon Korea Department of Environmental Engineering Hanseo University Seosan Chungnam 356-820 Korea Department of Environmental Engineering Hoseo University Asan Korea

In spite of the low temperature during the winter season and the high land environment, the wetland treatment system is gaining popularity in Korea because of its lower construction cost and simplicity in operation and maintenance. Many different types of wetland treatment systems have been built during the last 10 years, among which the free water surface wetland has been predominant. Most of the large-scale systems are government projects for improving the water quality of the streams flowing into the estuary dikes and reservoirs. The covering plants used in this system are different in different areas but cattails and reeds or their combinations are common. Constructed wetlands in Korea can be characterized by their shallow depths and short hydraulic residence times. There is no established flow pattern and configuration rules for constructing wetlands, but many efforts have been made with a view to improving their ecological function. Flow control is the most difficult problem in designing a riverbed or riparian wetland. There have been scores of flow rate control devices developed for wetlands, but none of them guarantee wetlands’ safety against flooding. In earlier wetland construction, the building materials were mainly soil. Recently, strong and durable building materials such as rocks, gravel beds, concrete and steel are used at vulnerable places to protect them from erosion. Our investigation indicated that the wetland system would be an appropriate technology because it is not only cheaper to construct, but also requires less maintenance work. However, we suffer from the reduced effectiveness in performance during the winter. We need to evaluate the partial treatment accomplished during 6 to 7 months per year.

关键词： constructed wetland wastewater treatment wetland system

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