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Subsurface damage pattern and formation mechanism of monocrystalline β-Ga_(2)O_(3) in grinding process

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Frontiers of Mechanical Engineering 2022年第2期17卷 117-127页

作者： Xin YANG Renke KANG Shang GAO Zihe WU xianglong zhu Key Laboratory for Precision and Non-Traditional Machining Technology of Ministry of Education Dalian University of TechnologyDalian 116024China

Monocrystalline beta-phase gallium oxide (β-Ga_(2)O_(3)) is a promising ultrawide bandgap semiconductor material. However, the deformation mechanism in ultraprecision machining has not yet been revealed. The aim of this study is to investigate the damage pattern and formation mechanism of monocrystalline β-Ga_(2)O_(3)in different grinding processes. Transmission electron microscopy was used to observe the subsurface damage in rough, fine, and ultrafine grinding processes. Nanocrystals and stacking faults existed in all three processes, dislocations and twins were observed in the rough and fine grinding processes, cracks were also observed in the rough grinding process, and amorphous phase were only present in the ultrafine grinding process. The subsurface damage thickness of the samples decreased with the reduction in the grit radius and the grit depth of cut. Subsurface damage models for grinding process were established on the basis of the grinding principle, revealing the mechanism of the mechanical effect of grits on the damage pattern. The formation of nanocrystals and amorphous phase was related to the grinding conditions and material characteristics. It is important to investigate the ultraprecision grinding process of monocrystalline β-Ga_(2)O_(3). The results in this work are supposed to provide guidance for the damage control of monocrystalline β-Ga_(2)O_(3)grinding process.

关键词： monocrystalline beta-phase gallium oxide grinding process subsurface damage nanocrystals amorphous phase

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Feasibility Study on Magnetorheological Finishing of Thin Copper Substrate

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Chinese Journal of Mechanical Engineering 2024年第6期37卷 173-182页

作者： Bo Pan Renke Kang Yunfei Zhang Kailong Li Dongxing Du Xiaoguang Guo Chao Wang Jiang Guo xianglong zhu Wen Huang Key Laboratory for Precision and Non‑Traditional Machining Technology of Ministry of Education Dalian University of TechnologyDalian 116024China Institute of Mechanical Manufacturing Technology China Academy of Engineering PhysicsMianyang 621999China

Thin copper substrates with high accuracy are highly required in precision physical ***,even using double-sided lapping,the flatness is still limited due to the accuracy of lapping plate,process vibration and so ***,as a subsequent process,this paper employs magnetorheological finishing(MRF)to further improve the ***,thin copper substrates,which are sensitive to the stress,deformed easily with uneven material removal on the ***,MRF is adopted on machining thin copper substrate for the first time considering deformation induced by stress.A finite element model is established to evaluate the deformation by residual stress,and the results show that the deformation tends to be more serious with the increase of the material *** to the simulation results,the material removal is optimized considering both deformation and efficiency,and a series of experiments are conducted on aΦ100×2.8 mm workpiece to verify the simulation *** experimental results show that the flatness is further improved from peak to valley(PV)6.6μm to PV 2.3μm with optimized processing ***,the feasibility of magnetorheological finishing on thin copper substrate is demonstrated.

关键词： Magnetorheological finishing Thin copper substrate Flatness Deformation

Kinetic and Sensitive Analysis of Tyrosinase Activity Using QD-Dopaquinone Electron Transfer Complexes

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Kinetic and Sensitive Analysis of Tyrosinase Activity Using ...

Kinetic and Sensitive Analysis of Matrix Metalloprotease 2 Based on Activatable T1-Recovery

第八届全国化学生物学学术会议

作者： xianglong zhu Jinhao Gao State Key Laboratory of Physical Chemistry of Solid Surfaces The Key Laboratory for Chemical Biology of Fujian ProvinceDepartment of Chemical BiologyCollege of Chemistry and Chemical EngineeringXiamen University

＜正＞The nanoscale size and unique optical properties of semiconductor quantum dots （QDs）have made attractive as central photoluminescent scaffolds for a variety of biosensing *** are highly sensitive to charge-tra... 详细信息

关键词： Quantum dot Fluorescence quenching Tyrosinase Electron accepter Dopaquinone

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Kinetic and Sensitive Analysis of Matrix Metalloprotease 2 B...

SnoRNAs: The promising targets for anti-tumor therapy

中国化学会第30届学术年会

作者： xianglong zhu Jinhao Gao State Key Laboratory of Physical Chemistry of Solid Surfaces The Key Laboratory for Chemical Biology of Fujian Province Department of Chemical Biology College of Chemistry and Chemical Engineering Xiamen University

Matrix Metalloprotease 2(MMP-2) is an important enzyme critical to extracellular matrix remodeling, especially cancer invasiveness, metastasis, and angiogenesis. Sensitive detection of MMP-2 activity in vitro and on cellular level is of great significance to medical diagnostics and prior treatment. Herein, we demonstrate an activatable T MRI strategy by using FeO-pep-Gd as NP-substrates for kinetic analysis of MMP-2. As the schematic representation, MMP-2 cleaved the peptide which links FeO and Gd-chelates, releasing the latter from the local magnetic field along with T-relaxation recovery. In addition, we introduced signal amplification into the sensing system to prove sensitivity effectively. This enzyme responding system based on T recovery was also explored on MMP-2 overexpressed HT-1080 human fibrosarcoma cells to evaluate its sensing capacity.

关键词： Matrix metalloprotease 2 cancer metastasis nanoparticle substrate T1 recovery enzymatic activity signal amplification

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Journal of Pharmaceutical Analysis 2024年第11期14卷 1588-1602页

作者： Xiaoyun Hu Wanlin Cui Min Liu Fangxiao Zhang Yingqi Zhao Mingrong Zhang Yuhang Yin Yalun Li Ying Che xianglong zhu Yuxuan Fan Xiaolan Deng Minjie Wei Huizhe Wu Department of Pharmacology School of PharmacyChina Medical UniversityShenyang110122China Liaoning Key Laboratory of Molecular Targeted Anti-tumor Drug Development and Evaluation Liaoning Cancer Immune Peptide Drug Engineering Technology Research CenterKey Laboratory of Precision Diagnosis and Treatment of Gastrointestinal TumorsMinistry of EducationChina Medical UniversityShenyang110122China Scientific Experimental Center School of PharmacyChina Medical UniversityShenyang110122China The Second Department of Infectious Diseases The First Affiliated Hospital of China Medical UniversityShenyang110001China Department of Anorectal Surgery The First Affiliated Hospital of China Medical UniversityShenyang110001China Department of Systems Biology Beckman Research Institute of City of HopeMonroviaCA91016USA Shenyang Kangwei Medical Laboratory Analysis Co. Ltd.Shenyang110000China

Recently,small nucleolar RNAs(snoRNAs)have transcended the genomic“noise”to emerge as pivotal molecular markers due to their essential roles in tumor *** evidence indicates a strong association between snoRNAs and critical clinical features such as tumor pathology and drug ***,snoRNA research has concentrated on two classical mechanisms:2'-O-ribose methylation and *** review specifically summarizes the novel regulatory mechanisms and functional patterns of snoRNAs in tumors,encompassing transcriptional,post-transcriptional,and post-translational *** further discuss the synergistic effect between snoRNA host genes(SNHGs)and snoRNAs in tumor *** importantly,snoRNAs extensively contribute to the development of tumor cell resistance as oncogenes or tumor suppressor ***,we provide a comprehensive review of the clinical diagnosis and treatment associated with snoRNAs and explore their significant potential as novel drug targets.

关键词： snoRNA Cancer snoRNA host gene Multidrug resistance Targeted therapy Tumor immune microenvironment

Kinetic and Sensitive Analysis of Tyrosinase Activity Using Electron Transfer Complexes:In Vitro and Intracellular Study

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Kinetic and Sensitive Analysis of Tyrosinase Activity Using ...

中国化学会第29届学术年会

作者： xianglong zhu Juan Hu Jinhao Gao State Key Laboratory of Physical Chemistry of Solid Surfaces The Key Laboratory for Chemical Biology of Fujian ProvinceDepartment of Chemical BiologyCollege of Chemistry and Chemical EngineeringXiamen University

Tyrosinase is an important marker of human diseases such as neurodegeneration associated with Parkinson’s disease and *** detection of tyrosinase activity in vitro and inside cells is of great significance to medical diagnostics and skin disorders *** this work,QDs functionalized with tyrosine and zwitterionic molecules construct a nanometer scale scaffold to test tyrosinase activity in vitro and inside *** oxidizes tyrosine to dopachrome and switches on the electron-transfer access which relates to fluorescence *** process curves reveal the enhanced enzymatic activity on conjugated nanoparticle-substrate,which leads to highly sensitive detection of tyrosinase as low as 1 *** is also demonstrated that QD-Tyr conjugates can sensitively probe intracellular tyrosinase in melanoma cells,which may promise the potential applications in diseases monitoring and medical diagnostics.

关键词： tyrosinase quantum dots fluorescence quenching enzymatic activity electron-transfer

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资本结构研究之动态权衡理论新证据

财经科学 2015年第8期 56-66页

作者：陶启智朱翔龙李亮西南财经大学金融学院

本文研究了并购交易对中国主并公司资本结构的影响,以检验关于动态权衡理论的假设。针对2000—2010年发生的158宗并购交易,通过托宾模型预测了主并公司在并购发生前后的最优杠杆率,并在此基础上研究了并购对杠杆率偏差的影响。结果显示... 详细信息

本文研究了并购交易对中国主并公司资本结构的影响,以检验关于动态权衡理论的假设。针对2000—2010年发生的158宗并购交易,通过托宾模型预测了主并公司在并购发生前后的最优杠杆率,并在此基础上研究了并购对杠杆率偏差的影响。结果显示,主并公司在并购前存在着资本结构对于最优值的偏差;主并公司运用并购来矫正该偏差,由于矫正过度,它们在并购交易完成后的长期内继续消除这种偏差。基于对经典研究方法的三点改进,本文结果显著支持动态权衡理论,并且比先前的研究更加符合经验证据。稳健性检验揭示,中国上市公司在资本结构方面的行为模式与美国上市公司高度一致。

关键词：资本结构公司并购主并公司杠杆率偏差

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磨削加工颤振稳定性研究综述

机械工程学报 2023年第21期59卷 15-33页

作者：朱子俊朱祥龙董志刚康仁科鲍岩大连理工大学高性能精密制造全国重点实验室大连116024

在磨削难加工材料制成或具有薄壁、大长径比、复杂曲面结构的零部件时,磨削系统颤振会直接影响零部件表面加工质量和轮廓精度,从而影响使用寿命。但是目前对磨削颤振系统产生机理,稳定性模型建立与分析的研究仍有不足。深入开展磨削加... 详细信息

在磨削难加工材料制成或具有薄壁、大长径比、复杂曲面结构的零部件时,磨削系统颤振会直接影响零部件表面加工质量和轮廓精度,从而影响使用寿命。但是目前对磨削颤振系统产生机理,稳定性模型建立与分析的研究仍有不足。深入开展磨削加工过程中颤振稳定性研究对于提升加工质量、保障磨削系统稳定运行具有重要意义。围绕磨削颤振机理、磨削稳定性建模与求解方法和应用进行综述,首先分析磨削系统稳定性的主要影响因素,深入讨论颤振的成因和磨削系统动力学建模进展;然后,从频域、时域、实验等方面重点分析磨削稳定性模型的求解方法,比较并归纳各种求解方法的过程原理、研究现状与优缺点;最后总结稳定性分析应用方法与现状,并对磨削加工颤振稳定性研究未来的发展方向进行展望。

关键词：磨削颤振稳定性分析动力学建模

湿式机械化学磨削单晶硅的软磨料砂轮及其磨削性能

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机械工程学报 2023年第3期59卷 328-336页

作者：张瑜康仁科高尚黄金星朱祥龙大连理工大学精密与特种加工教育部重点实验室大连116024

针对干式机械化学磨削(Mechanical chemical grinding,MCG)单晶硅过程中易产生磨削烧伤、粉尘多、加工环境差等问题,研制一种可用于湿式MCG单晶硅的新型软磨料砂轮,并对砂轮的磨削性能及其磨削单晶硅的材料去除机理进行研究。根据湿式... 详细信息

针对干式机械化学磨削(Mechanical chemical grinding,MCG)单晶硅过程中易产生磨削烧伤、粉尘多、加工环境差等问题,研制一种可用于湿式MCG单晶硅的新型软磨料砂轮,并对砂轮的磨削性能及其磨削单晶硅的材料去除机理进行研究。根据湿式机械化学磨削单晶硅的加工原理和要求,制备出以二氧化硅为磨料、改性耐水树脂为结合剂的新型软磨料砂轮。采用研制的软磨料砂轮对单晶硅进行磨削试验,通过检测加工硅片的表面/亚表面质量对湿式MCG软磨料砂轮的磨削性能进行分析,并与传统金刚石砂轮、干式MCG软磨料砂轮的磨削性能进行对比。采用X射线光电子能谱仪对磨削前后硅片的表面成分进行检测,分析湿式MCG加工硅片过程中发生的化学反应。结果表明,采用湿式MCG软磨料砂轮加工硅片的表面粗糙度Ra值为0.98 nm,亚表面损伤层深度为15 nm,湿式MCG软磨料砂轮磨削硅片的表面/亚表面质量远优于传统金刚石砂轮,达到干式MCG软磨料砂轮的加工效果,可实现湿磨工况下硅片的低损伤磨削加工。在湿式MCG过程中,单晶硅、二氧化硅磨粒与水发生了化学反应,在硅片表面生成易于去除的硅酸化合物,硅酸化合物进一步通过砂轮磨粒与硅片间的机械摩擦作用被磨粒从单晶硅表面去除,在机械与化学作用复合作用下实现硅片超低损伤磨削加工。

关键词：机械化学磨削硅片软磨料砂轮表面粗糙度亚表面损伤