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Doping engineering of iron oxide nanoparticles towards high performance and biocompatible T_(1)-weighted MRI contrast agents

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Rare Metals 2024年第1期43卷 298-308页

作者： Xue Xu Ping-Li Dong Yu-Yun Chai Run Yang Zhen-Hui Ma Chi-Chong Lu Department of Chemistry College of Chemistry and Materials EngineeringBeijing Technology and Business UniversityBeijing 100048China Department of Physics Beijing Technology and Business UniversityBeijing 100048China

Extremely small-sized iron oxide nanoparticles(IONPs) are of great interest in magnetic resonance imaging(MRI) due to their biosafety as an alternative to clinical gadolinium(Ⅲ) complexes-based contrast *** when the particle size is less than 10 nm,it has strong diffusion ability and deep penetration distance in tumor *** doping can significantly enhance the T_(1)contrast effect of nanoparticles by regulating the surface exposed ***,the nucleation and growth processes of multi-component synthesis systems are complex and difficult to be accurately controlled,leading to great challenges in the synthesis of ultra-small-sized nanoparticles with different components and ***,extremely smallsized superparamagnetic gadolinium-doped iron oxide nanoparticles(GdIONPs,Gd_(x)Fe_(3-x)O_(4) NPs) with adjustable doping amount and controllable size in the range of 3.5-7.5 nm were synthesized by thermal ***,as-synthesized GdIONPs were surface modified with a highly water-soluble and biocompatible carboxyl-polyethylene glycol-phosphoric acid ligand with high binding ***_(0.65)Fe_(2.35)O_(4) NPs exhibited very high r_(1) relaxivity of 10.6 mmol^(-1)·L·s^(-1) in terms of all metal concentrations and 49.0 mmol^(-1)·L·s^(-1) in terms of gadolinium alone,respectively,3 and 14 times higher than clinical T_(1) contrast agents(Gd-DTPA).GdIONPs can continuously obtain high resolution images of blood vessels,and can be used as an efficient and multifunctional contrast agent for MR T_(1)*** stable and efficient doping strategy provides an easy and effective method to individually optimize the magnetic properties of complex oxides and their relaxation effects for a variety of biomedical applications.

关键词： Iron oxide nanoparticles small size Magnetic resonance imaging Substitutional doping Gd dopant

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A low power cyclic ADC design for a wireless monitoring system for orthopedic implants

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Journal of Semiconductors 2009年第8期30卷 147-152页

作者：陈怡李福乐陈虹张春王志华 Tsinghua National Laboratory for Information Science and Technology Institute of MicroelectronicsTsinghua University

This paper presents a low power cyclic analog-to-digital convertor （ADC） design for a wireless monitoring system for orthopedic implants. A two-stage cyclic structure including a single to differential converter, two multiplying DAC functional blocks （MDACs） and some comparators is adopted, which brings moderate speed and moderate resolution with low power consumption. The MDAC is implemented with the common switched capacitor method. The 1.5-bit stage greatly simplifies the design of the comparator. The operational amplifier is carefully op- timized both in schematic and layout for low power and offset. The prototype chip has been fabricated in a United Microelectronics Corporation （UMC） 0.18-μm 1P6M CMOS process. The core of the ADC occupies only 0.12 mm2. With a 304.7-Hz input and 4-kHz sampling rate, the measured peak SNDR and SFDR are 47.1 dB and 57.8 dBc respectively and its DNL and INL are 0.27 LSB and 0.3 LSB, respectively. The power consumption of the ADC is only 12.5 μW in normal working mode and less than 150 nW in sleep mode.

关键词： monitoring system low power consumption small size analog to digital convertor single to differential convertor

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A review of soldering by localized heating

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China Welding 2023年第2期32卷 1-15页

作者：崔鹏杨婉春彭飞祝温博杨帆李明雨 Sauvage Laboratory for Smart Materials School of Materials Science and EngineeringHarbin Institute of Technology(Shenzhen)Shenzhen 518055China State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China

In recent years,the rapid development of the new energy industry has driven continuous upgrading of high-density and high-power *** the packaging and assembly process,the problem of differentiation of the thermal needs of different modules has become increasingly prominent,especially for small-size solder joints with high heat dissipation in high-power *** soldering is con-sidered a suitable choice to selectively heat the desired target while not affecting other heat-sensitive *** paper reviews several local-ized soldering processes,focusing on the size of solder joints,soldering materials,and current state of the *** localized solder-ing process was discovered to have unique *** requirements for small-size solder joints are met by laser soldering,microres-istance soldering,and self-propagating soldering;however,laser soldering has difficulty meeting the requirements for large heat dissipation,microresistance soldering requires the application of pressure to joints,and self-propagating soldering requires ignition ***,for small-size solder junctions,selective wave soldering,microwave soldering,and ultrasonic soldering are not *** the magnetic field can be focused on a tiny area and the output energy of induction heating is large,induction soldering can be employed as a significant trend in future research.

关键词： localized soldering high heat dissipation small size induction soldering focused heating

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Multi-Channel Monolithic Integrated Optic Fiber Bragg Grating Sensor Interrogator

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Photonic Sensors 2011年第3期1卷 281-288页

作者： Edgar A. MENDOZA Yan ESTERKIN Cornelia KEMPEN Zongjian SUN Redondo Optics Inc. 811 North Catalina Avenue Suite 1100 Redondo Beach CA 90277 USA

Fiber Bragg grating （FBG） is a mature sensing technology for the measurement of strain, vibration, acoustics, acceleration, pressure, temperature, moisture, and corrosion. It has gained rapid acceptance in civil, aerospace, chemical and petrochemical, medicine, aviation and automotive industries. The most prominent advantages of FBG are： small size and light weight, distributed array of FBG transducers on a single fiber, and immunity to radio frequency interference. However, a major disadvantage of FBG technology is that conventional state-of-the-art FBG interrogation system is typically bulky, heavy, and costly bench top instruments that are typically assembled from off-the-shelf fiber optic and optical components integrated with a signal electronics board into an instrument console. Based on the industrial need for a compact FBG interrogation system, this paper describes recent progress towards the development of miniature fiber Bragg grating sensor interrogator （FBG-TransceiverTM） system based on multi-channel monolithic integrated optic sensor microchip technology. The integrated optic microchip technology enables monolithic integration of all functionalities, both passive and active, of conventional bench top FBG sensor interrogator system, packaged in a miniaturized, low power operation, 2 cmx5 cm small form factor （SFF） package suitable for long-term structural health monitoring in applications where size, weight, and power are critical for operation.

关键词： Integrated optics monolithic fiber sensors structural health monitoring small size light weight low power

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