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Publications (10 of 640) Show all publications
Chen, M., Xue, S., Liu, L., Li, Z., Wang, H., Tan, C., . . . He, S. (2019). A highly stable optical humidity sensors based on nano-composite film. Sensors and actuators. B, Chemical, 287, 329-337
Open this publication in new window or tab >>A highly stable optical humidity sensors based on nano-composite film
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2019 (English)In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 287, p. 329-337Article in journal (Refereed) Published
Abstract [en]

We report a highly stable humidity sensor based on nanocomposite film obtained by depositing Au nanoparticles on the surface of 3-mercaptopropionic acid (MPA) capped CdTe quantum dots (QDs) and then modifying NaOH (CdTe@Au/NaOH). The CdTe@Au/NaOH film will form compound salts that can be dissolved or crystallized with humidity changes, resulting in a significant absorption variation of green light, which is very benefit for water vapor detection. In this study, we systematically investigated the influence on the performance of humidity sensing by varying the thickness of Au layer as well as the concentration of NaOH. Our results show that the quickest response-recovery time (˜less than 30 s) was found in the sensing film with the Au layer thickness of 20 nm and NaOH concentration of 1M, which can be ascribed to the combined effects of the better morphology and the yield of compound salts. The repeatable response and recovery measurements demonstrate that the designed sensors exhibit an ultralow humidity detection level with fast response-recovery time, high stability and reproducibility at room temperature. The simplicity, low fabrication cost, and wide working range of the humidity sensor will pave the way for its application in environments and gas detection.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Nano-composite film, Optical humidity sensors, Quantum dots, Transmission
National Category
Other Chemistry Topics
Identifiers
urn:nbn:se:kth:diva-246419 (URN)10.1016/j.snb.2019.02.051 (DOI)000461341700041 ()2-s2.0-85061797327 (Scopus ID)
Note

QC 20190401

Available from: 2019-04-01 Created: 2019-04-01 Last updated: 2019-04-03Bibliographically approved
Sun, F., Guo, S., Li, B., Liu, Y. & He, S. (2019). An Acoustic Metamaterial Lens for Acoustic Point-to-Point Communication in Air. Paper presented at IMENTE A, 2012, J APPL PHYS LETT, V100, Xu, 2014, SCIENTIFIC REPORTS, V4, ynolds D. D., 1981, Engineering Principles of Acoustics: Noise and Vibration Control, brovnitskii Yu. I., 2014, ACOUSTICAL PHYSICS, V60, P371 jumdar A., 2005, Journal of Optical and Fiber Communications Reports, V2, P345 ang Xue, 2014, APPLIED PHYSICS LETTERS, V104, ilbin T G, 2010, Geometry and Light: The Science of Invisibility, u Jie, 2013, SCIENTIFIC REPORTS, V3, nchis L., 2013, PHYSICAL REVIEW LETTERS, V110, o Fen, 2013, JOURNAL OF APPLIED PHYSICS, V113, Tinghua, 2012, ACOUSTICAL PHYSICS, V58, P642 Qiannan, 2012, APPLIED PHYSICS LETTERS, V101, en Huanyang, 2007, APPLIED PHYSICS LETTERS, V91, mmer Steven A., 2007, NEW JOURNAL OF PHYSICS, V9, nano Juan C., 2006, OPTICS EXPRESS, V14, P9627 Borui, 2018, APPLIED PHYSICS EXPRESS, V11, Borui, 2017, APPLIED PHYSICS EXPRESS, V10, n Fei, 2017, JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, V142, P1213 Guancong, 2016, SCIENCE ADVANCES, V2, mmer Steven A., 2016, NATURE REVIEWS MATERIALS, V1, ure Cedric, 2016, APPLIED PHYSICS LETTERS, V108, brovnitskii Yu. I., 2015, ACOUSTICAL PHYSICS, V61, P255 i Jun, 2012, NATURE COMMUNICATIONS, V3, ang Zixian, 2012, PHYSICAL REVIEW LETTERS, V108,. Acoustical Physics, 65(1), 1-6
Open this publication in new window or tab >>An Acoustic Metamaterial Lens for Acoustic Point-to-Point Communication in Air
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2019 (English)In: Acoustical Physics, ISSN 1063-7710, E-ISSN 1562-6865, Vol. 65, no 1, p. 1-6Article in journal (Refereed) Published
Abstract [en]

Acoustic metamaterials have become a novel and effective way to control sound waves and design acoustic devices. In this study, we design a 3D acoustic metamaterial lens (AML) to achieve point-to-point acoustic communication in air: any acoustic source (a speaker) in air enclosed by such an AML can produce an acoustic image where the acoustic wave is focused (the field intensity is at a maximum, and the listener can receive the information), while the acoustic field at other spatial positions is low enough that listeners can hear almost nothing. Unlike a conventional elliptical reflective mirror, the acoustic source can be moved around inside our proposed AML. Numerical simulations are given to verify the performance of the proposed AML.

Place, publisher, year, edition, pages
PLEIADES PUBLISHING INC, 2019
Keywords
acoustic metamaterials, focusing, Eaton lens
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-252419 (URN)10.1134/S1063771019010111 (DOI)000467043300001 ()2-s2.0-85065415437 (Scopus ID)
Conference
IMENTE A, 2012, J APPL PHYS LETT, V100, Xu, 2014, SCIENTIFIC REPORTS, V4, ynolds D. D., 1981, Engineering Principles of Acoustics: Noise and Vibration Control, brovnitskii Yu. I., 2014, ACOUSTICAL PHYSICS, V60, P371 jumdar A., 2005, Journal of Optical and Fiber Communications Reports, V2, P345 ang Xue, 2014, APPLIED PHYSICS LETTERS, V104, ilbin T G, 2010, Geometry and Light: The Science of Invisibility, u Jie, 2013, SCIENTIFIC REPORTS, V3, nchis L., 2013, PHYSICAL REVIEW LETTERS, V110, o Fen, 2013, JOURNAL OF APPLIED PHYSICS, V113, Tinghua, 2012, ACOUSTICAL PHYSICS, V58, P642 Qiannan, 2012, APPLIED PHYSICS LETTERS, V101, en Huanyang, 2007, APPLIED PHYSICS LETTERS, V91, mmer Steven A., 2007, NEW JOURNAL OF PHYSICS, V9, nano Juan C., 2006, OPTICS EXPRESS, V14, P9627 Borui, 2018, APPLIED PHYSICS EXPRESS, V11, Borui, 2017, APPLIED PHYSICS EXPRESS, V10, n Fei, 2017, JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA, V142, P1213 Guancong, 2016, SCIENCE ADVANCES, V2, mmer Steven A., 2016, NATURE REVIEWS MATERIALS, V1, ure Cedric, 2016, APPLIED PHYSICS LETTERS, V108, brovnitskii Yu. I., 2015, ACOUSTICAL PHYSICS, V61, P255 i Jun, 2012, NATURE COMMUNICATIONS, V3, ang Zixian, 2012, PHYSICAL REVIEW LETTERS, V108,
Note

QC 20190716

Available from: 2019-07-16 Created: 2019-07-16 Last updated: 2019-07-16Bibliographically approved
Xu, B., Zhao, K., Ying, Z., Sjoberg, D., He, W. & He, S. (2019). Analysis of Impacts of Expected RF EMF Exposure Restrictions on Peak EIRP of 5G User Equipment at 28 GHz and 39 GHz Bands. IEEE Access, 7, 20996-21005
Open this publication in new window or tab >>Analysis of Impacts of Expected RF EMF Exposure Restrictions on Peak EIRP of 5G User Equipment at 28 GHz and 39 GHz Bands
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2019 (English)In: IEEE Access, E-ISSN 2169-3536, Vol. 7, p. 20996-21005Article in journal (Refereed) Published
Abstract [en]

Above 6 GHz, radio frequency (RF) electromagnetic field (EMF) exposure from the mobile communication user equipment (UE) should be assessed in terms of incident power density, rather than specific absorption rate as below 6 GHz. Such regulatory RF EMF restrictions will constrain the transmit power of the UE and its peak equivalent isotropically radiated power (EIRP). This paper provides an analysis of the peak EIRP levels of UE containing code-book-based beamforming arrays at 28 GHz and 39 GHz. Different types of antenna elements, incremental element spacing, 4- and 8-element array configurations, and realistic housing integration are considered. The analysis and results show that in realistic housing integration, the 3GPP requirements on minimum peak EIRP can be generally met under the expected RF EMF exposure restrictions.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2019
Keywords
5G, antenna array, EIRP, RF EMF exposure, incident power density, millimeter wave, user equipment
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-247854 (URN)10.1109/ACCESS.2019.2897271 (DOI)000460554100001 ()2-s2.0-85062913955 (Scopus ID)
Note

QC 20190326

Available from: 2019-03-26 Created: 2019-03-26 Last updated: 2019-05-16Bibliographically approved
Li, J., Liu, H., Zhang, S., Zhang, Y. & He, S. (2019). Compact broadband circularly-polarised antenna with a backed cavity for UHF RFID applications. IET Microwaves, Antennas & Propagation, 13(6), 789-795
Open this publication in new window or tab >>Compact broadband circularly-polarised antenna with a backed cavity for UHF RFID applications
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2019 (English)In: IET Microwaves, Antennas & Propagation, ISSN 1751-8725, E-ISSN 1751-8733, Vol. 13, no 6, p. 789-795Article in journal (Refereed) Published
Abstract [en]

A compact broadband circularly-polarised (CP) antenna is designed with a novel method for universal ultra-high-frequency (UHF) radio-frequency identification (RFID) readers. It is composed of a compact ring-shaped patch which aims to decrease the size of the antenna. A quadrature 3 dB coupler placed below the ground plane creates 90 degrees phase differences to generate the CP radiation of the antenna. To improve the performance of the proposed antenna and minimise its size, the authors use a coupling feeding method, an FR4 dielectric slab, and a metal cavity. The coupled feeding is implemented to eliminate the mismatching between the long probe and the ring-shaped patch, and to improve the gain over the operating band. The introduction of an FR4 dielectric slab and a cavity can reduce the antenna size and improve the impedance matching and axial-ratio (AR) bandwidth. The antenna with a backed cavity can increase the front-to-back ratio remarkably and improve the CP performance further. The measured results show that the antenna with a low profile (0.45 lambda(0) x 0.45 lambda(0) x 0.06 lambda(0) at 915 MHz) has the impedance bandwidth of 30.2% (730-990 MHz) and 3 dB AR bandwidth of 24.2% (760-970 MHz). Both the impedance and the AR bandwidth cover the worldwide UHF RFID band.

National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-252971 (URN)10.1049/iet-map.2018.5321 (DOI)000468055500013 ()2-s2.0-85065993526 (Scopus ID)
Note

QC 20190812

Available from: 2019-08-12 Created: 2019-08-12 Last updated: 2019-08-12Bibliographically approved
Liu, Y., Guo, S. & He, S. (2019). Illusion Optics: Disguising with Ordinary Dielectric Materials. Advanced Materials, 31(6), Article ID 1805106.
Open this publication in new window or tab >>Illusion Optics: Disguising with Ordinary Dielectric Materials
2019 (English)In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 31, no 6, article id 1805106Article in journal (Refereed) Published
Abstract [en]

Illusion devices are usually designed using transformation optics. Here, a new method is proposed to achieve optical illusions without external devices by elaborately manipulating the scattering potential of an object. In contrast to the conventional transformation optics method, which completely replaces one object by the image of another object using complementary\restoring media and a superlens, the method described here is more of a cosmetic operation for an object, which modifies the scattering pattern of the object to mimic another object by exchanging their scattering potentials in two symmetrical areas in the wave vector domain. Only positive isotropic nonmagnetic materials are introduced in the present method, which is impossible using the conventional method because superlenses require negative-index materials. Both numerical simulations and experimental demonstrations are used to verify the performance of the illusion devices of this method.

Place, publisher, year, edition, pages
WILEY-V C H VERLAG GMBH, 2019
Keywords
illusion optics, isotropic dielectric materials, scattering potential, wave vector domains
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-246266 (URN)10.1002/adma.201805106 (DOI)000459630600009 ()30548888 (PubMedID)2-s2.0-85058405420 (Scopus ID)
Note

QC 20190326

Available from: 2019-03-26 Created: 2019-03-26 Last updated: 2019-05-13Bibliographically approved
Fei, C., Hong, X., Zhang, G., Ji, D., Wang, Y. & He, S. (2019). Improving the Performance of Long Reach UOWC With Multiband DFT-Spread. IEEE Photonics Technology Letters, 31(16), 1315-1318
Open this publication in new window or tab >>Improving the Performance of Long Reach UOWC With Multiband DFT-Spread
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2019 (English)In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 31, no 16, p. 1315-1318Article in journal (Refereed) Published
Abstract [en]

In this letter, a multiband discrete-Fourier-transform spread (DFT-spread) is introduced to reduce the peak-to-average-power ratio (PAPR) of discrete multitone (DMT)-based underwater optical wireless communication (UOWC) system. The performance of different multiband DFT-spread DMT schemes in a wide underwater transmission range (from 5 to 55 m at a fixed transmission data rate of 5.6 Gb/s) is experimentally investigated. The measured results show that the 1-band DFT-spread and 2-band DFT-spread DMT can significantly improve the system performance compared with the conventional clipping DMT, while the 1-band DFT-spread gives the best performance. Due to the single carrier frequency domain equalization-like characteristic, the 1-band DFT-spread exhibits a relatively uniform signal-to-noise ratio (SNR) profile, which shows the robustness to high frequency fading in the band-limited UOWC system. These intrinsic advantages could jointly ease the bit error rate (BER) deterioration in a long reach UOWC system. Furthermore, the measured data rate-distance product has reached 308 Gb/s*m (i.e., 55-m * 5.6 Gb/s), which to the best of our knowledge is the largest for the single modulation format.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2019
Keywords
Underwater optical wireless communication (UOWC), multiband DFT-spread, discrete multi-tone (DMT), visible laser diode (LD)
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-255725 (URN)10.1109/LPT.2019.2923527 (DOI)000476811600002 ()2-s2.0-85069793626 (Scopus ID)
Note

QC 20190814

Available from: 2019-08-14 Created: 2019-08-14 Last updated: 2019-08-14Bibliographically approved
Shi, K. Z., Bao, F. L., He, N. & He, S. (2019). Near-field heat transfer between graphene-Si grating heterostructures with multiple magnetic-polaritons coupling. International Journal of Heat and Mass Transfer, 134, 1119-1126
Open this publication in new window or tab >>Near-field heat transfer between graphene-Si grating heterostructures with multiple magnetic-polaritons coupling
2019 (English)In: International Journal of Heat and Mass Transfer, ISSN 0017-9310, E-ISSN 1879-2189, Vol. 134, p. 1119-1126Article in journal (Refereed) Published
Abstract [en]

Near-field thermal radiation (NFTR) between two graphene-covered Si grating (G/Si grating) heterostructures consisting of multilayered G/Si grating cells is investigated, in comparison with that between single-G/Si-grating-cell structures. The calculations are based on the scattering theory utilizing rigorous coupled-wave analysis (RCWA). It is found that strong magnetic polaritons (MPs) can be induced in the single G/Si grating cell, and coupling of multiple MPs can be observed in multilayered G/Si grating heterostructures, which leads to a broader band of high photon-tunnelling probabilities in the phase space. As a result, when the thickness of each grating layer is fixed, the heat flux of the 4-G/Si grating heterostructures, with chemical potential μ = 0.1 eV and grating period L x = 80 nm, is 1.65- and 9.12-fold larger than those of the 1-G/Si grating and only Si grating structures at d = 100 nm, respectively. When the total thickness of the entire G/Si grating heterostructure is fixed, the 1-G/Si grating model performs better than 2- or 4-G/Si grating models because higher loss inherited from additional graphene sheets would reduce the momenta of the near-unity energy transmission coefficient in the k-space.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Graphene-Si grating heterostructures, Multiple magnetic polaritons, Near-field thermal radiation, Surface plasmon polaritons
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-246435 (URN)10.1016/j.ijheatmasstransfer.2019.01.037 (DOI)000462418300094 ()2-s2.0-85061693692 (Scopus ID)
Note

QC 20190329

Available from: 2019-03-29 Created: 2019-03-29 Last updated: 2019-04-24Bibliographically approved
Sun, X., Ji, Z. & He, S. (2019). SHG- enhanced NIR- excited in vitro photodynamic therapy using composite nanoparticles of barium titanate and rose Bengal. RSC Advances, 9(14), 8056-8064
Open this publication in new window or tab >>SHG- enhanced NIR- excited in vitro photodynamic therapy using composite nanoparticles of barium titanate and rose Bengal
2019 (English)In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, no 14, p. 8056-8064Article in journal (Refereed) Published
Abstract [en]

Near infrared (NIR) light excited photodynamic therapy (PDT) has been considered as a possible way to increase the therapy depth. Besides the traditional two-photon excited PDT and upconversion PDT by rare-earth ion materials, SHG has drawn much attention recently to act as an additional choice to achieve NIR light excited PDT. Herein, by using the electrostatic absorption method, barium titanate and rose Bengal composite nanoparticles (BT@PAH/RB/PAH, BT-RB) were synthesized. Compared with rose Bengal (RB) molecules and a mixture of barium titanate nanoparticles and RB (BT + RB), BT-RB nanoparticles were shown to be able to produce more reactive oxygen species (ROS) ex vivo and in vitro. Afterwards, the SHG-enhanced localized PDT was applied on Hela cells, in which BT-RB nanoparticles showed a better performance than BT + RB. Our work has shown that the SHG-enhanced PDT has good prospects and the close combination of harmonic nanoparticles and photosensitizers may facilitate the development of novel reagents for NIR light excited PDT.

Place, publisher, year, edition, pages
Royal Society of Chemistry, 2019
National Category
Other Chemistry Topics
Identifiers
urn:nbn:se:kth:diva-249899 (URN)10.1039/c9ra00432g (DOI)000462646000057 ()2-s2.0-85062895044 (Scopus ID)
Note

QC 20190423

Available from: 2019-04-23 Created: 2019-04-23 Last updated: 2019-04-23Bibliographically approved
Guo, T., Sun, Y., Evans, J., Wang, N., Fu, Y. & He, S. (2019). Thermal management with a highly emissive and thermally conductive graphite absorber. AIP Advances, 9(2), Article ID 025224.
Open this publication in new window or tab >>Thermal management with a highly emissive and thermally conductive graphite absorber
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2019 (English)In: AIP Advances, ISSN 2158-3226, E-ISSN 2158-3226, Vol. 9, no 2, article id 025224Article in journal (Refereed) Published
Abstract [en]

Thermal management on a variety of length scales is essential for many industrial, solar and computational systems. Here we explore the thermal properties of a nearly perfect graphite absorber with both high emissivity and thermal conductivity which is fabricated by simple one-step etching. The hemispherical reflectance of the absorber is around 1% in the visible range and the normal specular reflectance is less than 1% from 1.5 mu m to 10 mu m. The thermal conductivity of the absorber is measured above 630 Wm(-1) K-1, which is 2.5 times larger than the aluminum used in commercial heat sinks. Heat dissipation testing indicates that a device is 3.7 +/- 2 degrees cooler with the graphite absorber as the heat spreader than a pristine graphite sheet and 9.1 +/- 2 degrees cooler than an Au-coated graphite sheet, primarily due to improved radiation cooling. A theoretical analysis accounts for the results. Further analysis suggests that the radiative heat dissipation is more prominent in the low-convection environment, especially for a convection coefficient below 10 Wm(-2) K-1. 

Place, publisher, year, edition, pages
AMER INST PHYSICS, 2019
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-247851 (URN)10.1063/1.5086064 (DOI)000460029500087 ()2-s2.0-85062261906 (Scopus ID)
Note

QC 20190326

Available from: 2019-03-26 Created: 2019-03-26 Last updated: 2019-04-04Bibliographically approved
Gong, C., Liu, W., He, N., Dong, H., Jin, Y. & He, S. (2019). Upconversion enhancement by a dual-resonance all-dielectric metasurface. Nanoscale, 11(4), 1856-1862
Open this publication in new window or tab >>Upconversion enhancement by a dual-resonance all-dielectric metasurface
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2019 (English)In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372, Vol. 11, no 4, p. 1856-1862Article in journal (Refereed) Published
Abstract [en]

Upconversion nanoparticles (UCNPs) have drawn much attention in the past decade due to their superior physicochemical features and great potential in biomedical and biophotonic studies. However, their low luminescence efficiency often limits their applications. Here, we demonstrated a dual-resonance all-dielectric metasurface to enhance the signals emitted by upconversion nanoparticles (NaYF4:Yb/Tm). An averaged upconversion signal enhancement of around 400 times is detected experimentally. The electric and magnetic dipole resonances of the metasurface are designed to enhance the local excitation field and the quantum efficiency of the upconversion nanoparticles, respectively. Furthermore, the collection efficiency is enhanced due to the directional emission of the UCNPs on the metasurface. Our approach provides a powerful tool to extend the sensing application potential of upconversion nanoparticles.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2019
National Category
Nano Technology
Identifiers
urn:nbn:se:kth:diva-246285 (URN)10.1039/c8nr08653b (DOI)000459910900034 ()30637422 (PubMedID)2-s2.0-85060399075 (Scopus ID)
Note

QC 20190325

Available from: 2019-03-25 Created: 2019-03-25 Last updated: 2019-04-04Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-3401-1125

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