|
Records |
Links |
|
Author |
Ryabchun, Sergey; Tong, Cheuk-Yu Edward; Blundell, Raymond; Gol'tsman, Gregory |
|
|
Title |
Stabilization scheme for hot-electron bolometer receivers using microwave radiation |
Type |
Journal Article |
|
Year |
2009 |
Publication |
IEEE Trans. Appl. Supercond. |
Abbreviated Journal |
IEEE Trans. Appl. Supercond. |
|
|
Volume |
19 |
Issue |
1 |
Pages |
14-19 |
|
|
Keywords |
HEB, mixer, Allan variance, stabilization, radiometer equation |
|
|
Abstract |
We present the results of a stabilization scheme for terahertz receivers based on NbN hot-electron bolometer (HEB) mixers that uses microwave radiation with a frequency much lower than the gap frequency of NbN to compensate for mixer current fluctuations. A feedback control loop, which actively controls the power level of the injected microwave radiation, has successfully been implemented to stabilize the operating point of the HEB mixer. This allows us to increase the receiver Allan time to 10 s and also improve the temperature resolution of the receiver by about 30% in the total power mode of operation. |
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
|
Editor |
|
|
|
Language |
|
Summary Language |
|
Original Title |
|
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
1051-8223 |
ISBN |
|
Medium |
|
|
|
Area |
|
Expedition |
|
Conference |
|
|
|
Notes |
|
Approved |
no |
|
|
Call Number |
RPLAB @ lobanovyury @ |
Serial |
559 |
|
Permanent link to this record |
|
|
|
|
Author |
Meledin, Denis; Pavolotsky, Alexey; Desmaris, Vincent.; Lapkin, Igor; Risacher, Christophe; Perez, Victor; Henke, Douglas; Nystrom, Olle; Sundin, Erik; Dochev, Dimitar; Pantaleev, Miroslav; Fredrixon, Mathias; Strandberg, Magnus; Voronov, Boris; Goltsman, Gregory; Belitsky, Victor |
|
|
Title |
A 1.3-THz balanced waveguide HEB mixer for the APEX telescope |
Type |
Journal Article |
|
Year |
2009 |
Publication |
IEEE Trans. Microw. Theory Techn. |
Abbreviated Journal |
|
|
|
Volume |
57 |
Issue |
1 |
Pages |
89-98 |
|
|
Keywords |
HEB, mixer, waveguide, balanced, NbN |
|
|
Abstract |
In this paper, we report about the development, fabrication, and characterization of a balanced waveguide hot electron bolometer (HEB) receiver for the Atacama Pathfinder EXperiment telescope covering the frequency band of 1.25–1.39 THz. The receiver uses a quadrature balanced scheme and two HEB mixers, fabricated from 4- to 5-nm-thick NbN film deposited on crystalline quartz substrate with an MgO buffer layer in between. We employed a novel micromachining method to produce all-metal waveguide parts at submicrometer accuracy (the main-mode waveguide dimensions are 90×180 μm). We present details on the mixer design and measurement results, including receiver noise performance, stability and “first-light†at the telescope site. The receiver yields a double-sideband noise temperature averaged over the RF band below 1200 K, and outstanding stability with a spectroscopic Allan time more than 200 s. |
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
|
Editor |
|
|
|
Language |
|
Summary Language |
|
Original Title |
|
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0018-9480 |
ISBN |
|
Medium |
|
|
|
Area |
|
Expedition |
|
Conference |
|
|
|
Notes |
|
Approved |
no |
|
|
Call Number |
RPLAB @ lobanovyury @ |
Serial |
554 |
|
Permanent link to this record |
|
|
|
|
Author |
Kawamura, J.; Blundell, R.; Tong, C.-Y. E.; Papa, D. C.; Hunter, T. R.; Paine, S. N.; Patt, F.; Gol'tsman, G.; Cherednichenko, S.; Voronov, B.; Gershenzon, E. |
|
|
Title |
Superconductive hot-electron-bolometer mixer receiver for 800-GHz operation |
Type |
Journal Article |
|
Year |
2000 |
Publication |
IEEE Trans. Microw. Theory Techn. |
Abbreviated Journal |
IEEE Trans. Microw. Theory Techn. |
|
|
Volume |
48 |
Issue |
4 |
Pages |
683-689 |
|
|
Keywords |
NbN HEB mixers, LO power, local oscillator power, saturation, linearity, dynamic range |
|
|
Abstract |
In this paper, we describe a superconductive hot-electron-bolometer mixer receiver designed to operate in the partially transmissive 350-μm atmospheric window. The receiver employs an NbN thin-film microbridge as the mixer element, in which the main cooling mechanism of the hot electrons is through electron-phonon interaction. At a local-oscillator frequency of 808 GHz, the measured double-sideband receiver noise temperature is TRX=970 K, across a 1-GHz intermediate-frequency bandwidth centered at 1.8 GHz. We have measured the linearity of the receiver and the amount of local-oscillator power incident on the mixer for optimal operation, which is PLO≈1 μW. This receiver was used in making observations as a facility instrument at the Heinrich Hertz Telescope, Mt. Graham, AZ, during the 1998-1999 winter observing season. |
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
|
Editor |
|
|
|
Language |
|
Summary Language |
|
Original Title |
|
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0018-9480 |
ISBN |
|
Medium |
|
|
|
Area |
|
Expedition |
|
Conference |
|
|
|
Notes |
|
Approved |
no |
|
|
Call Number |
RPLAB @ lobanovyury @ |
Serial |
573 |
|
Permanent link to this record |
|
|
|
|
Author |
Gershenzon, E. M.; Gershenzon, M. E.; Gol'tsman, G. N.; Karasik, B. S.; Semenov, A. D.; Sergeev, A. V. |
|
|
Title |
Light-induced heating of electrons and the time of the inelastic electron-phonon scattering in the YBaCuO compound |
Type |
Journal Article |
|
Year |
1987 |
Publication |
JETP Lett. |
Abbreviated Journal |
JETP Lett. |
|
|
Volume |
46 |
Issue |
6 |
Pages |
285-287 |
|
|
Keywords |
YBCO HTS HEB |
|
|
Abstract |
For the first time, measurements have been made on the electron energy relaxation time due to the electron--phonon interaction in films of the YBaCuO superconductor. The results indicate a significant intensification of the electron--phonon interaction in this compound as compared with normal superconducting metals. |
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
|
Editor |
|
|
|
Language |
|
Summary Language |
|
Original Title |
|
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
|
ISBN |
|
Medium |
|
|
|
Area |
|
Expedition |
|
Conference |
|
|
|
Notes |
|
Approved |
no |
|
|
Call Number |
|
Serial |
1706 |
|
Permanent link to this record |
|
|
|
|
Author |
Gershenzon, E. M.; Gershenzon, M. E.; Gol'tsman, G. N.; Semenov, A. D.; Sergeev, A. V. |
|
|
Title |
Nonselective effect of electromagnetic radiation on a superconducting film in the resistive state |
Type |
Journal Article |
|
Year |
1982 |
Publication |
JETP Lett. |
Abbreviated Journal |
JETP Lett. |
|
|
Volume |
36 |
Issue |
7 |
Pages |
296-299 |
|
|
Keywords |
HEB |
|
|
Abstract |
|
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
|
Editor |
|
|
|
Language |
|
Summary Language |
|
Original Title |
|
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
|
ISBN |
|
Medium |
|
|
|
Area |
|
Expedition |
|
Conference |
|
|
|
Notes |
Неселективное воздействие электромагнитного излучения на сверхпроводящую пленку в резистивном состоянии |
Approved |
no |
|
|
Call Number |
|
Serial |
1717 |
|
Permanent link to this record |
|
|
|
|
Author |
Pentin, Ivan; Finkel, Matvey; Maslennikov, Sergey; Vakhtomin, Yuri; Smirnov, Konstantin; Kaurova, Nataliya; Goltsman, Gregory |
|
|
Title |
Superconducting hot-electron-bolometer mixers for the mid-IR |
Type |
Journal Article |
|
Year |
2017 |
Publication |
Rus. J. Radio Electron. |
Abbreviated Journal |
Rus. J. Radio Electron. |
|
|
Volume |
|
Issue |
10 |
Pages |
|
|
|
Keywords |
IR NbN HEB mixers |
|
|
Abstract |
The work presents the result of development of the NbN superconducting hot-electron-bolometer (HEB) mixer. The sensitive element of the mixer is directly coupled to mid-IR radiation, and doesn’t have planar metallic antenna. Investigations of noise characteristics of NbN HEB mixer were performed at the frequency 28.4 THz (λ = 10.6 µm) by using gas-discharge CW CO2-laser without consideration of optical and electrical losses in the heterodyne receiver. The noise temperature of NbN HEB mixer with the size of the sensitive element 10 µm × 10 µm was 2320 K (~ 1.5hν/kB) at the heterodyne frequency of 28.4 THz. The noise temperature was determined by measuring the Y-factor taking into account the term which describes fluctuations of zero-point oscillations in accordance with the fluctuation-dissipation theorem of Calle-Welton. Isothermal method was used to estimate the absorbed heterodyne radiation power which was 9 µW at the optimal operating point for the minimum noise temperature of NbN HEB mixer. |
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
|
Editor |
|
|
|
Language |
Russian |
Summary Language |
|
Original Title |
|
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
1684-1719 |
ISBN |
|
Medium |
|
|
|
Area |
|
Expedition |
|
Conference |
|
|
|
Notes |
http://jre.cplire.ru/jre/oct17/9/abstract.html (Russian) Гетеродинный приемник со сверхпроводниковым смесителем на эффекте электронного разогрева для среднего инфракрасного диапазона |
Approved |
no |
|
|
Call Number |
|
Serial |
1747 |
|
Permanent link to this record |
|
|
|
|
Author |
Vystavkin, A. N. |
|
|
Title |
Estimation of noise equivalent power and design analysis of an andreev reflection hot-electron microbolometer for submillimeter radioastronomy |
Type |
Journal Article |
|
Year |
1999 |
Publication |
Rus. J. Radio Electron. |
Abbreviated Journal |
Rus. J. Radio Electron. |
|
|
Volume |
|
Issue |
10 |
Pages |
|
|
|
Keywords |
HEB, detector, bolometer |
|
|
Abstract |
Results of theoretical estimations and measurements of characteristics of an Andreev reflection hot-electron microbolometer for submillimeter radioastronomy made by different researchers are reviewed and analysed. Peculiarities and characteristics of the microbolometers using two types of microthermometer for measurement of the electron temperature increment under influence of the radiation: the SIN-junction and the transition-edge sensor (TES) with electrothermal feedback – are compared. Advantages of the microbolometer with the second type of the microthermometer when the TES is used simultaneously as the absorber of radiation are shown. Methods of achievement of the best noise equivalent power of the microbolometer in such version as well as methods of the matching the microbolometer with the incident radiation flow using planar antennas and with the channel of output signal measurement using a SQUID-picoammeter are considered. |
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
|
Editor |
|
|
|
Language |
|
Summary Language |
|
Original Title |
|
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
|
ISBN |
|
Medium |
|
|
|
Area |
|
Expedition |
|
Conference |
|
|
|
Notes |
|
Approved |
no |
|
|
Call Number |
|
Serial |
496 |
|
Permanent link to this record |
|
|
|
|
Author |
Karasik, B. S.; Il'in, K. S.; Pechen, E. V.; Krasnosvobodtsev, S. I. |
|
|
Title |
Diffusion cooling mechanism in a hot-electron NbC microbolometer mixer |
Type |
Journal Article |
|
Year |
1996 |
Publication |
Applied Physics Letters |
Abbreviated Journal |
Appl. Phys. Lett. |
|
|
Volume |
68 |
Issue |
16 |
Pages |
2285-2287 |
|
|
Keywords |
HEB mixer, diffusion cooling channel, diffusion channel |
|
|
Abstract |
|
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
|
Editor |
|
|
|
Language |
|
Summary Language |
|
Original Title |
|
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0003-6951 |
ISBN |
|
Medium |
|
|
|
Area |
|
Expedition |
|
Conference |
|
|
|
Notes |
|
Approved |
no |
|
|
Call Number |
|
Serial |
262 |
|
Permanent link to this record |
|
|
|
|
Author |
Karasik, B. S.; Elantiev, A. I. |
|
|
Title |
Noise temperature limit of a superconducting hot-electron bolometer mixer |
Type |
Journal Article |
|
Year |
1996 |
Publication |
Applied Physics Letters |
Abbreviated Journal |
Appl. Phys. Lett. |
|
|
Volume |
68 |
Issue |
6 |
Pages |
853-855 |
|
|
Keywords |
HEB mixer noise temperature, Johnson noise, thermal fluctuation noise, noise bandwidth |
|
|
Abstract |
|
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
|
Editor |
|
|
|
Language |
|
Summary Language |
|
Original Title |
|
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0003-6951 |
ISBN |
|
Medium |
|
|
|
Area |
|
Expedition |
|
Conference |
|
|
|
Notes |
|
Approved |
no |
|
|
Call Number |
|
Serial |
260 |
|
Permanent link to this record |
|
|
|
|
Author |
Floet, D. Wilms; Baselmans, J. J. A.; Klapwijk, T. M.; Gao, J. R. |
|
|
Title |
Resistive transition of niobium superconducting hot-electron bolometer mixers |
Type |
Journal Article |
|
Year |
1998 |
Publication |
Applied Physics Letters |
Abbreviated Journal |
Appl. Phys. Lett. |
|
|
Volume |
73 |
Issue |
19 |
Pages |
2826 |
|
|
Keywords |
HEB |
|
|
Abstract |
|
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
|
Editor |
|
|
|
Language |
|
Summary Language |
|
Original Title |
|
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0003-6951 |
ISBN |
|
Medium |
|
|
|
Area |
|
Expedition |
|
Conference |
|
|
|
Notes |
|
Approved |
no |
|
|
Call Number |
|
Serial |
543 |
|
Permanent link to this record |
|
|
|
|
Author |
Siddiqi, I.; Prober, D. E. |
|
|
Title |
Nb–Au bilayer hot-electron bolometers for low-noise THz heterodyne detection |
Type |
Journal Article |
|
Year |
2004 |
Publication |
Applied Physics Letters |
Abbreviated Journal |
Appl. Phys. Lett. |
|
|
Volume |
84 |
Issue |
8 |
Pages |
1404 |
|
|
Keywords |
HEB, mixers, dynamic range, saturation, LO power, local oscillator power, Nb |
|
|
Abstract |
The sensitivity of present Nb diffusion-cooled hot-electron bolometer (HEB) mixers is not quantum limited, and can be improved by reducing the superconducting transition temperature TC. Lowering TC reduces thermal fluctuations, resulting in a decrease of the mixer noise temperature TM. However, lower TC mixers have reduced dynamic range and saturate more easily due to background noise. We present 30 GHz microwave measurements on a bilayer HEB system, Nb–Au, in which TC can be tuned with Au layer thickness to obtain the maximum sensitivity for a given noise background. These measurements are intended as a guide for the optimization of THz mixers. Using a Nb–Au mixer with TC = 1.6 K, we obtain TM = 50 K with 2 nW of local oscillator (LO) power. Good mixer performance is observed over a wide range of LO power and bias voltage and such a device should not exhibit saturation in a THz receiver. |
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
|
Editor |
|
|
|
Language |
|
Summary Language |
|
Original Title |
|
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0003-6951 |
ISBN |
|
Medium |
|
|
|
Area |
|
Expedition |
|
Conference |
|
|
|
Notes |
|
Approved |
no |
|
|
Call Number |
|
Serial |
571 |
|
Permanent link to this record |
|
|
|
|
Author |
Fu, K.; Zannoni, R.; Chan, C.; Adams, S. H.; Nicholson, J.; Polizzi, E.; Yngvesson, K. S. |
|
|
Title |
Terahertz detection in single wall carbon nanotubes |
Type |
Journal Article |
|
Year |
2008 |
Publication |
Applied Physics Letters |
Abbreviated Journal |
Appl. Phys. Lett. |
|
|
Volume |
92 |
Issue |
3 |
Pages |
033105 |
|
|
Keywords |
HEB, single wall, carbon nanotube, CNT, SWNT, SWCNT, terahertz detection, THz |
|
|
Abstract |
It is reported that terahertz radiation from 0.69 to 2.54 THz has been sensitively detected in a device consisting of bundles of carbon nanotubes containing single wall metallic carbon nanotubes, quasioptically coupled through a lithographically fabricated antenna, and a silicon lens. The measured data are consistent with a bolometric detection process in the metallic tubes and the devices show promise for operation well above 4.2 K. |
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
|
Editor |
|
|
|
Language |
|
Summary Language |
|
Original Title |
|
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0003-6951 |
ISBN |
|
Medium |
|
|
|
Area |
|
Expedition |
|
Conference |
|
|
|
Notes |
NEP is not shown |
Approved |
no |
|
|
Call Number |
|
Serial |
566 |
|
Permanent link to this record |
|
|
|
|
Author |
Hajenius, M.; Baselmans, J. J. A.; Baryshev, A.; Gao, J. R.; Klapwijk, T. M.; Kooi, J. W.; Jellema, W.; Yang, Z. Q. |
|
|
Title |
Full characterization and analysis of a terahertz heterodyne receiver based on a NbN hot electron bolometer |
Type |
Journal Article |
|
Year |
2006 |
Publication |
J. Appl. Phys. |
Abbreviated Journal |
|
|
|
Volume |
100 |
Issue |
7 |
Pages |
074507 |
|
|
Keywords |
HEB |
|
|
Abstract |
|
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
|
Editor |
|
|
|
Language |
|
Summary Language |
|
Original Title |
|
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0021-8979 |
ISBN |
|
Medium |
|
|
|
Area |
|
Expedition |
|
Conference |
|
|
|
Notes |
|
Approved |
no |
|
|
Call Number |
RPLAB @ s @ |
Serial |
385 |
|
Permanent link to this record |
|
|
|
|
Author |
Burke, P. J.; Schoelkopf, R. J.; Prober, D. E.; Skalare, A.; Karasik, B. S.; Gaidis, M. C.; McGrath, W. R.; Bumble, B.; LeDuc, H. G. |
|
|
Title |
Mixing and noise in diffusion and phonon cooled superconducting hot-electron bolometers |
Type |
Journal Article |
|
Year |
1999 |
Publication |
J. Appl. Phys. |
Abbreviated Journal |
|
|
|
Volume |
85 |
Issue |
3 |
Pages |
1644-1653 |
|
|
Keywords |
HEB, mixer |
|
|
Abstract |
|
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
|
Editor |
|
|
|
Language |
|
Summary Language |
|
Original Title |
|
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0021-8979 |
ISBN |
|
Medium |
|
|
|
Area |
|
Expedition |
|
Conference |
|
|
|
Notes |
|
Approved |
no |
|
|
Call Number |
|
Serial |
556 |
|
Permanent link to this record |
|
|
|
|
Author |
Zorin, M.; Lindgren, M.; Danerud, M.; Karasik, B.; Winkler, D.; Gol'tsman, G.; Gershenzon, E. |
|
|
Title |
Nonequilibrium and bolometric responses of YBaCuO thin films to high-frequency modulated laser radiation |
Type |
Journal Article |
|
Year |
1995 |
Publication |
J. Supercond. |
Abbreviated Journal |
J. Supercond. |
|
|
Volume |
8 |
Issue |
1 |
Pages |
11-15 |
|
|
Keywords |
YBCO HTS HEB |
|
|
Abstract |
Picosecond nonequilibrium and slow bolometric responses to infrared radiation from a patterned high-T c superconducting (HTS) film in resistive and normal states deposited onto LaAlO3, NdGaO3, and MgO substrates were investigated using both pulse and modulation techniques. The response time of 35 ps to a laser pulse of 17 ps FWHM has been observed. The intrinsic response time of the fast process is expected to be about a few picoseconds. The modulation technique, being free from the disadvantages of pulse methods (poor sensitivity, limited dynamic range), makes the detailed study of a number of relaxation processes possible. Besides the nonequilibrium response, two kinds of bolometric processes, namely phonon transport through the film-substrate interface and phonon thermal diffusion in a substrate, manifest themselves in certain frequency dependences. |
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
|
Editor |
|
|
|
Language |
|
Summary Language |
|
Original Title |
|
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0896-1107 |
ISBN |
|
Medium |
|
|
|
Area |
|
Expedition |
|
Conference |
|
|
|
Notes |
|
Approved |
no |
|
|
Call Number |
|
Serial |
1630 |
|
Permanent link to this record |