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Soft metamaterial with programmable ferromagnetism

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Microsystems & Nanoengineering 2022年第6期8卷 217-223页

作者： Kerem Kaya Emre Iseri Wouter van der Wijngaart Division of Micro and nanosystems KTH Royal Institute of TechnologyStockholm 10044Sweden

Magnetopolymers are of interest in smart material applications;however,changing their magnetic properties post synthesis is *** this study,we introduce easily programmable polymer magnetic composites comprising 2D lattices of droplets of solid-liquid phase change material,with each droplet containing a single magnetic dipole *** composites are ferromagnetic with a Curie temperature defined by the rotational freedom of the particles above the droplet melting *** demonstrate magnetopolymers combining high remanence characteristics with Curie temperatures below the composite degradation *** easily reprogram the material between four states:(1)a superparamagnetic state above the melting point which,in the absence of an external magnetic field,spontaneously collapses to;(2)an artificial spin ice state,which after cooling forms either;(3)a spin glass state with low bulk remanence,or;(4)a ferromagnetic state with high bulk remanence when cooled in the presence of an external magnetic *** observe the spontaneous emergence of 2D magnetic vortices in the spin ice and elucidate the correlation of these vortex structures with the external bulk *** also demonstrate the easy programming of magnetically latching structures.

关键词： composites composite ferromagnetic

Linear-grating hybridized electromagnetic-triboelectric nanogenerator for sustainably powering portable electronics

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Nano Research 2016年第4期9卷 974-984页

作者： Kewei Zhang Ya Yang Beijing institute of Nanoenergy and nanosystems Chinese Academy of Sciences Beijing 100083 China

Utilizing a nanogenerator to scavenge mechanical energy from our living environment is an effective method to solve the power source issue of portable electronics. We report a linear-grating hybridized electromagnetic-triboelectric nanogenerator for scavenging the mechanical energy generated from sliding motions to sustainably power certain portable electronics. The hybridized nano- generator consists of a slider and a stator in the structural design, and possesses a 66-segment triboelectric nanogenerator （TENG） and a 9-segment electromagnetic generator （EMG） in the functional design. At a sliding acceleration of 20 m/s2 the hybridized nanogenerator can deliver maximum powers of 102.8 mW for the TENG at a loading resistance of 0.4 Mr2 and 103.3 mW for the EMG at a loading resistance of 6 kf2. With an optimal hybridized combination of the TENG with a transformer and the EMG with a power management circuit, a 10 mF capacitor can be easily charged to 2.8 V in 20 s. A packaged hybridized nanogenerator with a light weight of 140 g and small dimensions of 12 cm× 4 cm× 1.6 cm excels in scavenging low-frequency sliding energy to sustainably power portable electronics.

关键词： energy harvesting hybridized nanogenerator conjunction operation sliding motion self-powered electronics

Tiny MEMS-Based Pressure Sensors in the Measurement of Intracranial Pressure

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Tsinghua Science and Technology 2014年第2期19卷 161-167页

作者： Yanhang Zhang Zhaohua Zhang Bo Pang Li Yuan Tianling Ren the institute of Microelectronics Tsinghua University the Beijing institute of Nanoenergy and nanosystems Chinese Academy of Sciences

This study presents a tiny pressure sensor which is used to measure the Intracranial Pressure （ICP）. The sensor is based on the piezoresistive effect. The piezoresistive pressure sensor is simulated and designed by using nonlinear programming optimizing and Finite Element Analysis （FEA） tools. Two kinds of sensor sizes are designed in the case of childhood and adult. The sensors are fabricated by Microelectro Mechanical Systems （MEMS） process. The test results yield sensitivities of 1.033x 10-2 mV/kPa for the childhood type detection and 1.257x 10-2 mV/kPa for the adult detection with sensor chip sizes of 0.40x0.40 mm2 and 0.50x0.50 mm2, respectively. A novel method for measuring ICP is proposed because of the tiny sizes. Furthermore, relative errors for sensitivity of pressure sensors are limited within 4.76%. Minimum Detectable Pressure （MDP） reaches 128.4 Pa in average.

关键词： intracranial pressure tiny sensors finite element analysis

A low power 2.5-5 GHz low-noise amplifier using 0.5-μm GaAs pHEMT technology

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Journal of Semiconductors 2012年第10期33卷 62-65页

作者：彭洋洋陆科杰隋文泉 Nanoelectronic Platform Zhejiang-California Nanosystems InstituteZhejiang University

A two-stage 2.5-5 GHz monolithic low-noise amplifier（LNA） has been fabricated using 0.5-μm enhanced mode AlGaAs/GaAs pHEMT *** achieve wide operation bandwidth and low noise figure,the proposed LNA uses a wideband matching network and a negative feedback *** results from 2.5 to 5 GHz demonstrate a minimum of 2.4-dB noise figure and 17-dB *** input and output return loss exceeded -10-dB across the *** power consumption of this LNA is 33 *** to the author＇s knowledge,this is the lowest power consumption LNA fabricated in 0.5-μm AlGaAs/GaAs pHEMT with the comparable performance.

关键词： LNA GaAs pHEMT MMIC microwave

Micro packaged MEMS pressure sensor for intracranial pressure measurement

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Journal of Semiconductors 2015年第6期36卷 76-79页

作者：刘雄姚言马嘉豪张龑航王谦张兆华任天令 Beijing institute of Nanoenergy and nanosystems Chinese Academy of Sciences institute of Microelectronics Tsinghua University

This paper presents a micro packaged MEMS pressure sensor for intracranial pressure measurement which belongs to bioMEMS. It can be used in lumbar puncture surgery to measure intracranial pressure. Minia- turization is key for lumbar puncture surgery because the sensor must be small enough to allow it be placed in the reagent chamber of the lumbar puncture needle. The size of the sensor is decided by the size of the sensor chip and package. Our sensor chip is based on silicon piezoresistive effect and the size is 400 × 400 μm2. It is much smaller than the reported polymer intracranial pressure sensors such as liquid crystal polymer sensors. In terms of package, the traditional dual in-line package obviously could not match the size need, the minimal size of recently reported MEMS-based intracranial pressure sensors after packaging is 10 × 10 mm2. In this work, we are the first to introduce a quad flat no-lead package as the package form of piezoresistive intracranial pressure sensors, the whole size of the sensor is minimized to only 3 × 3 mm2. Considering the liquid measurement environment, the sensor is gummed and waterproof performance is tested; the sensitivity of the sensor is 0.9 × 10-2 mV/kPa.

关键词： intracranial pressure measurement lumbar puncture surgery bioMEMS quad flat no-lead package waterproof test

GaAs pHEMT multi-band/multi-mode SP9T switch for quad-band GSM and UMTS handsets applications

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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第4期12卷 317-322页

作者： Xiao-ying WANG Wen-ting GUO Yang-yang PENG Wen-quan SUI Zhejiang California International nanosystems institute (ZCNI) Zhejiang University Hangzhou 310029 China

A multi-band/multi-mode single-pole nine-throw (SP9T) switch for GSM/UMTS (global system for mobile communications/universal mobile telecommunication system) systems is *** switch consists of a GaAs 0.5μm pseudomorphic high-electron mobility transistor (pHEMT) radio frequency (RF) switches module and Si complementary metal-oxide-semiconductor (COMS) digital module with an encoder and a DC boost *** isolation and high linearity are achieved by a series-shunt switch structure and the DC boost circuit,*** switch shows a measured insertion loss of 0.4 dB at 0.8 GHz for GSM transmit arms,0.7 dB at 0.9 GHz and 0.9 dB at 1.8 GHz for GSM receive arms,and 0.6 dB at 1.8 GHz for UMTS *** switch introduces 2nd and 3rd harmonic suppression levels less than 64 dBc at 37 dBm input *** between transmit and receive terminals are more than 48 dB when one transmit arm is *** size of the RF switches module is 1.5 mm×1.1 mm,and the size of the digital module is 1.3 mm×0.63 mm with gold bonding wires connecting these two modules.

关键词： GSM UMTS Single-pole nine-throw (SP9T) pHEMT Encoder DC boost

Fully enclosed hybrid electromagnetic-triboelectric nanogenerator to scavenge vibrational energy

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Nano Research 2016年第8期9卷 2226-2233页

作者： Ting Quan Ya Yang Beijing institute of Nanoenergy and nanosystems Chinese Academy of Sciences National Center for Nanoscience and Technology Beijing 100083 China

We propose a fully enclosed hybrid nanogenerator consisting of five elec- tromagnetic generators （EMGs） and four triboelectric nanogenerators （TENGs）. Under a vibration frequency of 15.5 Hz, one TENG can deliver a high output voltage of approximately 24 V and a low output current of approximately 24 μA, whereas one EMG can deliver a low output voltage of approximately 0.8 V and a high output current of approximately 0.5 mA. By integrating five rectified EMGs in series and four rectified TENGs in parallel, the hybrid nanogenerator can be used to charge a home-made Li-ion battery from 1 to 1.9 V in 6.3 h. By using the hybrid nanogenerator to scavenge the vibrational energy produced by human hands, a temperature-humidity sensor can be sustainably powered by the nanogenerator, which is capable of charging the 200 ~F system power capacitor from 0 to 2 V in 15 s, and sustainably power the sensor in 29 s.

关键词： hybrid nanogenerator electromagnetic triboelectric vibration energy Li-ion battery

Effect of HTS Superconductors on Homogeneity of Measurement Field in Low Field Nuclear Magnetic Resonance Detection

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Chinese Physics Letters 2010年第8期27卷 250-252页

作者：董慧张懿 KRAUSE Hans-Joachim 谢晓明 State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences Shanghai 200050 institute of bio- and nanosystems Forschungszentrum Jiilich. D-52425 Jiilieh Germany Graduate University of the Chinese Academy of Sciences Beijing 100049

In recent years, superconducting quantum interference devices （SQUIDs） have been demonstrated to be useful in the low field nuclear magnetic resonance （NMR） measurements. The high temperature superconducting （HTS） SQUID used in our experiments has a frequency-independent sensitivity of 40-50fT/Hz^1/2. When a liquid nitrogen cooled LC circuit is employed to form a tuned circuit with the SQUID, the sensitivity of the system can be further enhanced. The LC circuit consists of a capacitor and a coil made of copper wire or HTS tape, which is inductively coupled to the SQUID. However, the homogeneity of the measurement field deteriorates because of the HTS tape coil in the proximity of the sample. In contrast, the thin film SQUID with a washer area of 1 cm^2 has no effect on the NMR signal. Therefore, the impairment of the measurement field homogeneity in the case of different superconducting elements nearby is discussed by examining the free induction decay signals at 9 kHz. It is found that a square superconducting film with an area of i cm^2 may compensate for the inhomogeneity of the measurement field after the adjustment of its position.

关键词： HIGH temperature superconductors NUCLEAR magnetic resonance SUPERCONDUCTING quantum interference devices PHYSICS experiments LIQUID nitrogen SENSITIVITY analysis

The effect of nitrogen annealing on lithium ion intercalation in nickel-doped lithium trivanadate

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Science Bulletin 2016年第8期61卷 587-593页

作者： Yaguang Liu Cuiping Zhang Chaofeng Liu Huanqiao Song Xihui Nan Guozhong Cao Beijing institute of Nanoenergy and nanosystems Chinese Academy of Sciences Department of Materials and Engineering University of Washington

The communication reports an exploratory experimental study on the effects of nitrogen annealing on lithium ion intercalation in nickel-doped lithium trivana- date cathodic electrodes for lithium ion batteries. It shows good rate performance with discharge capacities of 348.6, 252.6, 191.9 and 96.7 mAh g-1 at 0.2, 0.5, 1 and 5 C, respectively. Nitrogen annealing resulted in the formation of parasitic secondary-phase LiVzO5 and appreciably increased tetravalent vanadium ions compensated with oxygen vacancies, which would enhance the electronic conductivity and lithium ion diffusivity and promote the interface interaction and deintercalation process, and thus lead to the enhanced lithium ion intercalation properties. The possible impacts of the parasitic secondary-phase LiV205 on the lithium ion intercalation performance have also been discussed.

关键词： Nitrogen annealing Nickel-dopedlithium trivanadate Oxygen vacancies Parasiticsecondary phase